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| Severe acute respiratory syndrome (SARS) is frequently complicated with acute respiratory failure. In this article, we aim to focus on the management of the subgroup of SARS patients who are critically ill. Most SARS patients would require high flow oxygen supplementation, 20-30% required intensive care unit (ICU) or high dependency care, and 13-26% developed acute respiratory distress syndrome (ARDS). In some of these patients, the clinical course can progress relentlessly to septic shock and/or multiple organ dysfunction syndrome (MODS). The management of critically ill SARS patients requires timely institution of pharmacotherapy where applicable and supportive treatment (oxygen therapy, noninvasive and invasive ventilation). Superimposed bacterial and other opportunistic infections are common, especially in those treated with mechanical ventilation. Subcutaneous emphysema, pneumothoraces and pneumomediastinum may arise spontaneously or as a result of positive ventilatory assistance. Older age is a consistently a poor prognostic factor. Appropriate use of personal protection equipment and adherence to infection control measures is mandatory for effective infection control. Much of the knowledge about the clinical aspects of SARS is based on retrospective observational data and randomized-controlled trials are required for confirmation. Physicians and scientists all over the world should collaborate to study this condition which may potentially threaten human existence. | description |
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| Lau, Arthur Chun-Wing, Yam, Loretta Yin-Chun, So, Loletta Kit-Ying | authors |
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| Discriminating between elderly and young using a fractal dimension analysis of centre of pressure. | name |
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| The aim of this project was to evaluate the use of a new analysis technique, fractal dimension analysis, for quantification of quiet stance centre of pressure (COP). By using a fractal dimension analysis of COP, it might be possible to gain more information about control during quiet stance than traditional analyses have previously allowed. The current project considered a group of young healthy participants and a group of elderly healthy participants to compare traditional measures of COP against a fractal dimension analysis of COP. Results indicated that both types of analyses are able to distinguish between eyes open and eyes closed in the elderly group. However, the fractal dimension analysis more accurately detected differences between the participant groups when standing with their eyes closed. Based on these results it is suggested that fractal dimension analysis is more informative about posture control than traditional measures. It is suggested that a fractal dimension type of analysis can be incorporated into clinical testing to identify patients with pathologies. | description |
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| Doyle, Tim L A, Dugan, Eric L, Humphries, Brendan, Newton, Robert U | authors |
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| Study of the early steps of the Hepatitis B Virus life cycle. | name |
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| Hepatitis B virus (HBV) is a human pathogen, causing the serious liver disease. Despite considerable advances in the understanding of the natural history of HBV disease, most of the early steps in the virus life cycle remain unclear. Virus attachment to permissive cells, fusion and penetration through cell membranes and subsequent genome release, are largely a mystery. Current knowledge on the early steps of HBV life cycle has mostly come from molecular cloning, expression of individual genes and studies of the infection of duck hepatitis B virus (DHBV) with duck primary duck hepatocytes. However, considering of the difference of the surface protein of HBV and DHBV both in the composition and sequence, the degree to which information from DHBV applies to human HBV attachment and entry may be limited. A major obstacle to the study HBV infection is the lack of a reliable and sensitive in vitro infection system. We have found that the digestion of HBV and woodchuck hepatitis virus (WHBV) by protease V8 led to the infection of HepG2 cell, a cell line generally is refractory for their infection [Lu et al. J Virol. 1996. 70. 2277-2285 . Lu et al. Virus Research. 2001. 73(1): 27-4].. Further studies showed that a serine protease inhibitor Kazal (SPIK) was over expressed in the HepG2 cells. Therefore, it is possible that to silence the over expressed SPIK and thus to reinstate the activity of indispensable cellular proteases can result in the restoration of the susceptibility of HepG2 cells for HBV infection. The establishing a stable cell line for study of the early steps of HBV life cycle by silencing of SPIK is discussed. | description |
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| Lu, Xuanyong, Block, Timothy | authors |
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| The Syndrome of Frontonasal Dysplasia, Callosal Agenesis, Basal Encephalocele, and Eye Anomalies - Phenotypic and Aetiological Considerations. | name |
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| We report ten sporadic cases of Brazilian patients with facial midline defects, callosal agenesis, basal encephalocele, and ocular anomalies. This very rare cluster of anomalies has been well reported before. However, only until recently it is recognized as a syndrome belonging to frontonasal dysplasia spectrum. The ten cases confirm a distinct clinical entity and help to define the phenotype more precisely than previously. Up to now etiology remains unknown, although we conjecture that it is due to a mutation in TGIF gene. | description |
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| Richieri-Costa, Antonio, Guion-Almeida, Maria Leine | authors |
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| The primary prevention of birth defects: Multivitamins or folic acid? | name |
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| Periconceptional use of folic acid alone or in multivitamin supplements is effective for the primary prevention of neural-tube defects. The Hungarian randomized and two-cohort controlled trials showed that periconceptional multivitamin supplementation can reduce the occurrence of some other structural birth defects, i.e. congenital abnormalities. These findings were supported by many, but not all observational studies. Recently there have been two main debated questions. The first one is whether the use of folic acid alone or folic acid-containing multivitamins is better. The second one is connected with the dilemma of whether high dose of folic acid (e.g. 5 mg) might be better than a daily multivitamin with 0.4 - 0.8 mg of folic acid. Comparison of the pooled data of two Hungarian trials using a multivitamin containing 0.8 mg folic acid and the data of the Hungarian Case-Control Surveillance of Congenital Abnormalities using high dose of folic acid seemed to be appropriate to answer these questions. Multivitamins containing 0.4 - 0.8 mg of folic acid were more effective for the reduction of neural-tube defects than high dose of folic acid. Both multivitamins and folic acid can prevent some part of congenital cardiovascular malformations. Only multivitamins were able to reduce the prevalence at birth of obstructive defects of urinary tract, limb deficiencies and congenital pyloric stenosis. However, folic acid was effective in preventing some part of rectal/anal stenosis/atresia, and high dose of folic acid had effect in preventing some orofacial clefts. The findings are consistent that periconceptional multivitamin and folic acid supplementation reduce the overall occurrence of congenital abnormalities in addition to the demonstrated effect on neural-tube defects. | description |
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| Czeizel, Andrew E | authors |
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| Inhibition of calmodulin-dependent phosphodiesterase induces apoptosis in human leukemic cells. | name |
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| Cytosolic extracts from a human lymphoblastoid B-cell line, RPMI-8392, established from a patient with acute lymphocytic leukemia, contain two major forms of cyclic nucleotide phosphodiesterase (PDE): Ca2+-calmodulin dependent PDE (PDE1) and cAMP-specific PDE (PDE4). In contrast, normal quiescent human peripheral blood lymphocytes (HPBL) are devoid of PDE1 activity [Epstein, P. M., Moraski, S., Jr., and Hachisu, R. (1987) Biochem. J. 243, 533-539]. Using reverse transcription-polymerase chain reaction (RT-PCR), we show that the mRNA encoding the 63-kDa form of PDE1 (PDE1B1) is expressed in RPMI-8392 cells, but not in normal, resting HPBL. This mRNA is, however, induced in HPBL following mitogenic stimulation by phytohemagglutinin (PHA). Also using RT-PCR, the full open reading frame for human PDE1B1 cDNA was cloned from RPMI-8392 cells and it encodes a protein of 536 amino acids with 96% identity to bovine, rat, and mouse species. RT-PCR also identifies the presence of PDE1B1 in other human lymphoblastoid and leukemic cell lines of B- (RPMI-1788, Daudi) and T-(MOLT-4, NA, Jurkat) cell origin. Inhibition of PDE1 or PDE4 activity by selective inhibitors induced RPMI-8392 cells, as well as the other cell lines, to undergo apoptosis. Culture of RPMI-8392 cells with an 18-bp phosphorothioate antisense oligodeoxynucleotide, targeted against the translation initiation region of the RPMI-8392 mRNA, led to a specific reduction in the amount of PDE1B1 mRNA after 1 day, and its disappearance after 2 days, and induced apoptosis in these cells in a sequence specific manner. This suggests that PDEs, particularly PDE1B1, because its expression is selective, may be useful targets for inducing the death of leukemic cells. | description |
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| Jiang, X, Li, J, Paskind, M, Epstein, P M | authors |
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| Zoidogamy in fossil gymnosperms: The centenary of a concept, with special reference to prepollen of late Paleozoic conifers. | name |
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| This year is the centenary of the surprising discovery in 1896 of zoidogamy in extant cycadophytes and Ginkgo. But by coincidence, also in the same year, the concept of prepollen was introduced. The morphology of prepollen was considered justification for the probable production of motile antherozoids in extinct gymnosperms. In this paper, the history of the prepollen concept is briefly outlined. It is emphasized that, in addition to well-known examples in pteridosperms and cordaitaleans, a prepollen condition also occurred among late Paleozoic conifers. | description |
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| Poort, R J, Visscher, H, Dilcher, D L | authors |
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| Discovery of an algal mitochondrial carbonic anhydrase: molecular cloning and characterization of a low-CO2-induced polypeptide in Chlamydomonas reinhardtii. | name |
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| In green unicellular algae, several polypeptides are induced upon exposure to limiting CO2. We report here on the localization and characterization of one of these, a 22-kDa polypeptide in Chlamydomonas reinhardtii. This nuclear-encoded polypeptide is induced in the mitochondria by a lowering of the partial pressure of CO2 in the growth medium from 5% to air CO2 levels. Sequencing of two different cDNA clones coding for the polypeptide identified it as a 20.7-kDa beta-type carbonic anhydrase (CA; carbonate dehydratase, carbonate hydro-lyase, EC 4.2.1.1). The two clones differ in their nucleotide sequences but code for identical proteins, showing that this CA is encoded by at least two genes. Northern blot hybridization reveals that mRNA transcripts are only present in cells transferred to air CO2 levels. A comparison of the deduced amino acid sequence with those of other beta-CAs shows the largest degree of similarity with CA from the cyanobacterium Synechocystis (50% identity and 66% similarity). To our knowledge, this is the first identification and characterization of a mitochondrial CA from a photosynthetic organism. | description |
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| Eriksson, M, Karlsson, J, Ramazanov, Z, Gardeström, P, Samuelsson, G | authors |
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| Use of surface-enhanced laser desorption ionization-time-of-flight to identify heat shock protein 70 isoforms in closely related species of the virilis group of Drosophila. | name |
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| The 70-kDa heat shock protein (Hsp) family in all Drosophila species includes 2 environmentally inducible family members, Hsp70 and Hsp68. Two-dimensional gel electrophoresis revealed an unusual pattern of heat shock-inducible proteins in the species of the virilis group. Trypsin fingerprinting and microsequencing of tryptic peptides using ProteinChip Array technology identified the major isoelectric variants of Hsp70 family, including Hsp68 isoforms that differ in both molecular mass and isoelectric point from those in Drosophila melanogaster. The peculiar electrophoretic mobility is consistent with the deduced amino acid sequence of corresponding hsp genes from the species of the virilis group. | description |
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| Zatsepina, Olga G, Karavanov, Alexander A, Garbuz, David G, Shilova, Victoria, Tornatore, Peter, Evgen'ev, Michael B | authors |
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| Effects of hypoxia on stress proteins in the piglet heart at birth. | name |
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| Hypoxia at birth represents a very stressful event that can result in severe lifelong consequences in different tissues, including those of the heart. Heat shock and other associated stress proteins are involved in cellular protection, but their roles are not clearly defined at the time of birth. Newborn piglets were subjected to 5% oxygen and 95% nitrogen for either 1 or 4 hours. They were allowed to recover over periods of 1 to 68 hours. The relative levels of alphaB-crystallin, HspB8, Hsp20, Hsp27, Hsp60, and Hsp70 as well as nitric oxide synthases (NOS) (endothelial NOS, inducible NOS, neuronal NOS) were examined by Western blot analysis. Surprisingly, alphaB-crystallin expression was drastically increased in animals submitted to hypoxia. The hypoxia-associated factor HIFlalpha was also strongly and rapidly overexpressed. Heme oxygenase 1 was also increased. To a lesser extent, neuronal NOS was also increased in the left ventricle of animals submitted to hypoxia. This work clearly shows that the Hsp chaperone alphaB-crystallin is strongly overexpressed in the left ventricle of animals submitted to hypoxia. This observation dissociates the response to low oxygenation of alphaB-crystallin and other stress-associated proteins including Hsp27, and it indicates that heme oxygenase is not alone among HSPs in its oxygen-related gene expression. | description |
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| Louapre, Pamela, Grongnet, Jean F, Tanguay, Robert M, David, Jean C | authors |
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| Factors governing the substrate recognition by GroEL chaperone: a sequence correlation approach. | name |
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| The chaperonin GroEL binds to a large number of polypeptides, prevents their self-association, and mediates appropriate folding in a GroES and adenosine triphosphate-dependent manner. But how the GroEL molecule actually recognizes the polypeptide and what are the exact GroEL recognition sites in the substrates are still poorly understood. We have examined more than 50 in vivo substrates as well as well-characterized in vitro substrates, for their binding characteristics with GroEL. While addressing the issue, we have been driven by the basic concept that GroES, being the cochaperonin of GroEL, is the best-suited substrate for GroEL, as well as by the fact that polypeptide substrate and GroES occupy the same binding sites on the GroEL apical domain. GroES interacts with GroEL through selective hydrophobic residues present on its mobile loop region, and we have considered the group of residues on the GroES mobile loop as the key element in choosing a substrate for GroEL. Considering the hydrophobic region on the GroES mobile loop as the standard, we have attempted to identify the homologous region on the peptide sequences in the proteins of our interest. Polypeptides have been judged as potential GroEL substrates on the basis of the presence of the GroES mobile loop-like hydrophobic segments in their amino acid sequences. We have observed 1 or more GroES mobile loop-like hydrophobic patches in the peptide sequence of some of the proteins of our interest, and the hydropathy index of most of these patches also seems to be approximately close to that of the standard. It has been proposed that the presence of hydrophobic patches having substantial degree of hydropathy index as compared with the standard segment is a necessary condition for a peptide sequence to be recognized by GroEL molecules. We also observed that the overall hydrophobicity is also close to 30% in these substrates, although this is not the sufficient criterion for a polypeptide to be assigned as a substrate for GroEL. We found that the binding of aconitase, alpha-lactalbumin, and murine dihydrofolate reductase to GroEL falls in line with our present model and have also predicted the exact regions of their binding to GroEL. On the basis of our GroEL substrate prediction, we have presented a model for the binding of apo form of some proteins to GroEL and the eventual formation of the holo form. Our observation also reveals that in most of the cases, the GroES mobile loop-like hydrophobic patch is present in the unstructured region of the protein molecule, specifically in the loop or beta-sheeted region. The outcome of our study would be an essential feature in identifying a potential substrate for GroEL on the basis of the presence of 1 or more GroES mobile loop-like hydrophobic segments in the amino acid sequence of those polypeptides and their location in three-dimensional space. | description |
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| Chaudhuri, Tapan K, Gupta, Prateek | authors |
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| Clonogenicity of human leukemic cells protected from cell-lethal agents by heat shock protein 70. | name |
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| Pretreatment of human leukemia THP-1 cells with heat shock protein Hsp70 (Hsp70) protected them from the cell-lethal effects of the topoisomerase II inhibitor, lucanthone and from ionizing radiation. Cell viability was scored in clonogenic assays of single cells grown in liquid medium containing 0.5% methyl cellulose. Colonies were observed and rapidly scored after staining with the tetrazolium salt, 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide. The frequency of abasic sites in the deoxyribonucleic acid (DNA) of THP-1 cells was reduced when these cells were treated with Hsp70. Hsp70 is presumed to have protected the cells by promoting repair of cell DNA, in agreement with previous studies that showed that Hsp70 enhanced base excision repair by purified enzymes. The shoulders of radiation dose-response curves were enhanced by pretreatment of cells with Hsp70 and, importantly, were reduced when cells were transfected with ribonucleic acid designed to silence Hsp70. Hsp70 influenced repair of sublethal damage after radiation. | description |
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| Bases, Robert | authors |
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| Expression of heat shock proteins and heat shock protein messenger ribonucleic acid in human prostate carcinoma in vitro and in tumors in vivo. | name |
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| Heat shock proteins (HSPs) are thought to play a role in the development of cancer and to modulate tumor response to cytotoxic therapy. In this study, we have examined the expression of hsf and HSP genes in normal human prostate epithelial cells and a range of prostate carcinoma cell lines derived from human tumors. We have observed elevated expressions of HSF1, HSP60, and HSP70 in the aggressively malignant cell lines PC-3, DU-145, and CA-HPV-10. Elevated HSP expression in cancer cell lines appeared to be regulated at the post-messenger ribonucleic acid (mRNA) levels, as indicated by gene chip microarray studies, which indicated little difference in heat shock factor (HSF) or HSP mRNA expression between the normal and malignant prostate cell lines. When we compared the expression patterns of constitutive HSP genes between PC-3 prostate carcinoma cells growing as monolayers in vitro and as tumor xenografts growing in nude mice in vivo, we found a marked reduction in expression of a wide spectrum of the HSPs in PC-3 tumors. This decreased HSP expression pattern in tumors may underlie the increased sensitivity to heat shock of PC-3 tumors. However, the induction by heat shock of HSP genes was not markedly altered by growth in the tumor microenvironment, and HSP40, HSP70, and HSP110 were expressed abundantly after stress in each growth condition. Our experiments indicate therefore that HSF and HSP levels are elevated in the more highly malignant prostate carcinoma cells and also show the dominant nature of the heat shock-induced gene expression, leading to abundant HSP induction in vitro or in vivo. | description |
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| Tang, Dan, Khaleque, Md Abdul, Jones, Ellen L, Theriault, Jimmy R, Li, Cheng, Wong, Wing Hung, Stevenson, Mary Ann, Calderwood, Stuart K | authors |
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| CD95-mediated alteration in Hsp70 levels is dependent on protein stabilization. | name |
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| Engagement of death receptors induces caspase activation and apoptosis. A recent study reported altered protein expression, including increased Hsp70 levels during CD95-mediated apoptosis. Here, we examined the mechanism underlying increased Hsp70 levels in cells challenged with a monoclonal antibody directed against the CD95 receptor. Levels of Hsp70 were found to increase in a dose-dependent manner, occurring independently of either heat shock factor 1 activation or the accumulation of Hsp70 messenger ribonucleic acid (mRNA), suggesting the involvement of posttranslational modifications. Inhibition of translation and de novo protein synthesis by cycloheximide resulted in Hsp70 protein levels diminishing over time in control cells, whereas its level remained constant during CD95 signaling. In addition, death receptor activation through exposure of cells to tumor necrosis factor-related apoptosis-inducing ligand did not alter Hsp70 levels. These findings demonstrate that receptor-specific signaling through the CD95 increases the stability of Hsp70 protein, rather than mRNA, when compared with control cells. The results describe a novel mechanism of heat shock protein accumulation, where increased protein stability and reduced turnover, is the mechanism by which Hsp70 accumulates in cells during CD95-mediated apoptosis. | description |
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| Concannon, Caoimhín G, FitzGerald, Una, Holmberg, Carina I, Szegezdi, Eva, Sistonen, Lea, Samali, Afshin | authors |
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| Zebrafish Hsp70 is required for embryonic lens formation. | name |
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| Heat shock proteins (Hsps) were originally identified as proteins expressed after exposure of cells to environmental stress. Several Hsps were subsequently shown to play roles as molecular chaperones in normal intracellular protein folding and targeting events and to be expressed during discrete periods in the development of several embryonic tissues. However, only recently have studies begun to address the specific developmental consequences of inhibiting Hsp expression to determine whether these molecular chaperones are required for specific developmental events. We have previously shown that the heat-inducible zebrafish hsp70 gene is expressed during a distinct temporal window of embryonic lens formation at normal growth temperatures. In addition, a 1.5-kb fragment of the zebrafish hsp70 gene promoter is sufficient to direct expression of a gfp reporter gene to the lens, suggesting that the hsp70 gene is expressed as part of the normal lens development program. Here, we used microinjection of morpholino-modified antisense oligonucleotides (MOs) to reduce Hsp70 levels during zebrafish development and to show that Hsp70 is required for normal lens formation. Hsp70-MO-injected embryos exhibited a small-eye phenotype relative to wild-type and control-injected animals, with the phenotype discernable during the second day of development. Histological and immunological analysis revealed a small, underdeveloped lens. Numerous terminal deoxynucleotidyl transferase-mediated dUTP-fluoroscein nick-end labeling (TUNEL)-positive nuclei appeared in the lens of small-eye embryos after 48 hours postfertilization (hpf), whereas they were no longer apparent in untreated embryos by this age. Lenses transplanted from hsp70-MO-injected embryos into wild-type hosts failed to recover and retained the immature morphology characteristic of the small-eye phenotype, indicating that the lens phenotype is lens autonomous. Our data suggest that the lens defect in hsp70-MO-injected embryos is predominantly at the level of postmitotic lens fiber differentiation, a result supported by the appearance of mature lens organization in these embryos by 5 days postfertilization, once morpholino degradation or dilution has occurred. | description |
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| Evans, Tyler G, Yamamoto, Yoshiyuki, Jeffery, William R, Krone, Patrick H | authors |
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| Expression of mdr49 and mdr65 multidrug resistance genes in larval tissues of Drosophila melanogaster under normal and stress conditions. | name |
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| In situ expression of 2 multidrug resistance genes, mdr49 and mdr65, of Drosophila melanogaster was examined in wild-type third instar larval tissues under physiological conditions and after heat shock or colchicine feeding. Expression of these 2 genes was also examined in tumorous tissues of lethal (2) giant larvae I(2)gl4 mutant larvae. These 2 mdr genes show similar constitutive expression in different larval tissues under physiological conditions. However, they are induced differentially by endogenous (tumorous growth) and exogenous stresses (colchcine feeding or heat shock): whereas heat shock and colchicine feeding induce mdr49, tumorous condition is accompanied by enhanced expression of mdr49 and mdr65 genes. | description |
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| Tapadia, Madhu G, Lakhotia, S C | authors |
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| HLA-DR regulation and the influence of GM-CSF on transcription, surface expression and shedding. | name |
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| Low surface HLA-DR expression is a feature in sepsis. However, the mechanisms that regulate HLA-DR expression have not been elucidated. The current study investigates regulation of HLA-DR gene transcription, post transcriptional events and shedding of surface HLA-DR, as well as the regulation of HLA-DR by GM-CSF and an immunomodulatory cytokine. Plasma and PBMC were collected from septic patients and healthy volunteers. An ELISA was developed to measure soluble HLA. PCR techniques were used to determine HLA-DR mRNA levels, and flow cytometry and fluorescent microscopy were used for measurement of surface expressed and intracellular HLA-DR. Septic patients fulfilling the criteria of the American College of Chest Physicians (ACCP) for sepsis were recruited for the study (n=70). HLA-DR was measured on three consecutive days, days seven and fourteen. Patients were excluded from the study if on immunosuppressive therapy. Results: Higher levels of shed HLA-DR were found in the plasma of septic patients compared to healthy controls. The level of HLA-DR mRNA was significantly lower in septic patients compared to healthy controls, however an increased intracellular HLA-DR expression was observed. When HL-60 cells were treated with GM-CSF, gene transcription, surface expression and shedding of HLA-DR were all up-regulated. These results indicate that the mechanisms involved in the regulation of HLA-DR in sepsis include shedding of HLA-DR from the cell surface and regulation of HLA-DR gene transcription. Post-translational processing of HLA-DR was also seen to be compromised. GM-CSF was shown to regulate HLA-DR at all these levels. | description |
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| Perry, Sara E, Mostafa, Sobhy M, Wenstone, Richard, Shenkin, Alan, McLaughlin, Paul J | authors |
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| Anti-tumorigenic and Pro-apoptotic effects of CKBM on gastric cancer growth in nude mice. | name |
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| Natural botanical products can be integrated with western medicine to optimize the treatment outcome, increase immune function and minimize the side effects from western drug treatment. CKBM is a combination of herbs and yeasts formulated based on traditional Chinese medicinal principles. Previous study has demonstrated that CKBM is capable of improving immune responsiveness through the induction of cytokine mediators, such as TNF-alpha and IL-6. In this study, we aimed to investigate the effect of this immunomodulatory drug on gastric cancer growth using a human xenograft model. Gastric cancer tissues were implanted subcutaneously into athymic nude mice followed by a 14-day or 28-day of CKBM treatment. Results showed that higher doses of CKBM (0.4 or 0.8 ml/mouse/day) produced a dose-dependent inhibitory effect on gastric tumor growth after 28-day drug treatment. This was associated with a decrease of cellular proliferation by 30% with concomitant increase in apoptosis by 97% in gastric tumor cells when compared with the control group. In contrast, CKBM showed no effect on angiogenesis in gastric tumors. This study demonstrates the anti-tumorigenic action of CKBM on gastric cancer probably via inhibition of cell proliferation and induction of apoptosis, and provides future potential targets of this drug candidate on cancer therapy. | description |
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| Shin, Vivian Yvonne, So, Wallace Hau-Leung, Liu, Edgar Shiu-Lam, Wu, Ying-Jye, Pang, Shiu-Fun, Cho, Chi-Hin | authors |
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| An Increased Risk of Osteoporosis during Acquired Immunodeficiency Syndrome. | name |
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| Osteoporosis is characterized by decreased bone mineral density and mechanistic imbalances of bone tissue that may result in reduced skeletal strength and an enhanced susceptibility to fractures. Osteoporosis in its most common form affects the elderly (both sexes) and all racial groups of human beings. Multiple environmental risk factors like acquired immune deficiency syndrome (AIDS) are believed to be one of the causes of osteoporosis. Recently a high incidence of osteoporosis has been observed in human immunodeficiency virus (HIV) infected individuals. The etiology of this occurrence in HIV infections is controversial. This problem seems to be more frequent in patients receiving potent antiretroviral therapy. In AIDS, the main suggested risk factors for the development of osteoporosis are use of protease inhibitors, longer duration of HIV infection, lower body weight before antiretroviral therapy, high viral load. Variations in serum parameters like osteocalcin, c-telopeptide, levels of elements like Calcium, Magnesium, Phosphorus, concentration of vitamin-D metabolites, lactate levels, bicarbonate concentrations, amount of alkaline phosphatase are demonstrated in the course of development of osteoporosis. OPG/RANKL/RANK system is final mediator of bone remodeling. Bone mineral density (BMD) test is of added value to assess the risk of osteoporosis in patients infected with AIDS. The biochemical markers also aid in this assessment. Clinical management mostly follows the lines of treatment of osteoporosis and osteopenia. | description |
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| Annapoorna, N, Rao, G Venkateswara, Reddy, N S, Rambabu, P, Rao, K R S Samabasiva | authors |
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| Comparative study of serum Na(+ )and K(+ ) levels in senile cataract patients and normal individuals. | name |
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| Many factors such as aging, changes in blood electrolytes levels, and possibly family history are involved in senile cataract formation. Changes in serum electrolytes levels can induce changes in aqueous electrolytes levels and effect on lens metabolism and probably cataract formation. In this paper, we study serum level of Na(+ )and K(+) in senile cataract patients and normal individuals. Methods and materials: 155 senile cataract patients scheduled for cataract surgery in eye clinic of Rasoul hospital and 155 normal individuals were selected. Serum Na(+) and K(+) levels were measured by Flame Photometry technique and means compared between two groups by t-test. Results: 1. Mean serum Na(+) level in senile cataract patients and normal individuals was 144.96 +/- 6.04 mEq/lit and 140.88 +/- 2.27 mEq/lit respectively, and there was statistically significant difference (P<0.0001). 2. Mean serum K(+) level in senile cataract patients and normal individuals was 4.20 +/- 0.34 mEq/lit and 4.15 +/- 0.32 mEq/lit respectively, and there was no statistically significant difference. Conclusion: Serum Na(+ )level in senile cataract patients was higher than normal individuals in this study. This result might suggest that diets with high Na(+) content are a risk factor for age-related cataract formation, as high Na(+) content of the diet leads to high level of serum Na(+), which in turn contributes to formation of age-related cataract. | description |
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| Mirsamadi, Mansour, Nourmohammadi, Issa, Imamian, Manuchehr | authors |
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| A review of anatomical and mechanical factors affecting vertebral body integrity. | name |
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| Background: The aetiology of osteoporotic vertebral fracture is multifactorial and may be conceptualised using a systems framework. Previous studies have established several correlates of vertebral fracture including reduced vertebral cross-sectional area, weakness in back extensor muscles, reduced bone mineral density, increasing age, worsening kyphosis and recent vertebral fracture. Alterations in these physical characteristics may influence biomechanical loads and neuromuscular control of the trunk and contribute to changes in subregional bone mineral density of the vertebral bodies. Methods: This review discusses factors that have received less attention in the literature, which may contribute to the development of vertebral fracture. A literature review was conducted using electronic databases including Medline, Cinahl and ISI Web of Science to examine the potential contribution of trabecular architecture, subregional bone mineral density, vertebral geometry, muscle force, muscle strength, neuromuscular control and intervertebral disc integrity to the aetiology of osteoporotic vertebral fracture. Interpretation: A better understanding of factors such as biomechanical loading and neuromuscular control of the trunk may help to explain the high incidence of subsequent vertebral fracture after sustaining an initial vertebral fracture. Consideration of these issues may be important in the development of prevention and management strategies. | description |
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| Briggs, Andrew M, Greig, Alison M, Wark, John D, Fazzalari, Nicola L, Bennell, Kim L | authors |
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| Elevated plasma homocysteine is positively associated with age independent of C677T mutation of the methylenetetrahydrofolate reductase gene in selected Egyptian subjects. | name |
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| This study aimed to evaluate the plasma homocysteine (tHcy) and folate levels as well as the methylenetetrahydrofolate reductase (MTHFR) C677T mutation in Egyptian subjects. Fasting total homocysteine (tHcy) and the (MTHFR) C677T mutation were evaluated in 50 healthy young control males (age 35-50 years, Gp1), 50 elderly males age ranged between 50-75 years without any cardiovascular diseases (Gp2) and 50 age matched elderly male patients (Gp3) with myocardial infarction. There was a significant elevation of plasma tHcy in the patients group and Gp2 compared to the young control group (Gp1). The total plasma homocysteine (tHcy) in the control group, Gp2 and the patients group were 17.99 +/- 9.76, 39.9 +/- 20.06 and 43.8 +/- 13.13 mumol/L respectively. The frequency of the TT genotype was 12% in the patient group compared with 8 % in the young healthy controls and elderly subjects (Gp2). The CT genotype constituted 36%, 48% and 44% in the control group, Gp2 and the patients group respectively. There was no significant difference in the occurrence of the TT genotype between the studied groups. Plasma tHcy correlated positively with age, total cholesterol, urea, creatinine, glucose levels and carotid intimal thickness (CIT). Conclusion: The MTHFR mutation does not seem to be associated with either high tHcy or the occurrence of cardiovascular diseases in the studied patients. However, elevated plasma tHcy level positively correlates with age in the studied subjects. | description |
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| El-Sammak, Mohamed, Kandil, Mona, El-Hifni, Safaa, Hosni, Randa, Ragab, Mahmoud | authors |
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| Monte Carlo Commissioning of Low Energy Electron Radiotherapy Beams using NXEGS Software. | name |
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| This work is a report on the commissioning of low energy electron beams of a medical linear accelerator for Monte Carlo dose calculation using NXEGS software (NXEGS version 1.0.10.0, NX Medical Software, LLC). A unique feature of NXEGS is automated commissioning, a process whereby a combination of analytic and Monte Carlo methods generates beam models from dosimetric data collected in a water phantom. This study uses NXEGS to commission 6, 9, and 12 MeV electron beams of a Varian Clinac 2100C using three applicators with standard inserts. Central axis depth-dose, primary axis and diagonal beam profiles, and output factors are the measurements necessary for commissioning of the code. We present a comparison of measured dose distributions with the distributions generated by NXEGS, using confidence limits on seven measures of error. We find that confidence limits are typically less than 3% or 3 mm, but increase with increasing source to surface distance (SSD) and depth at or beyond R(50). We also investigate the dependence of NXEGS' performance on the size and composition of data used to commission the program, finding a weak dependence on number of dose profiles in the data set, but finding also that commissioning data need be measured at only two SSDs. | description |
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| Both, Joseph A, Pawlicki, Todd | authors |
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| Gene Therapy: The Potential Applicability of Gene Transfer Technology to the Human Germline. | name |
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| The theoretical possibility of applying gene transfer methodologies to the human germline is explored. Transgenic methods for genetically manipulating embryos may in principle be applied to humans. In particular, microinjection of retroviral vector appears to hold the greatest promise, with transgenic primates already obtained from this approach. Sperm-mediated gene transfer offers potentially the easiest route to the human germline, however the requisite methodology is presently underdeveloped. Nuclear transfer (cloning) offers an alternative approach to germline genetic modification, however there are major health concerns associated with current nuclear transfer methods. It is concluded that human germline gene therapy remains for all practical purposes a future possibility that must await significant and important advances in gene transfer technology. | description |
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| Smith, Kevin R | authors |
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| Tyrosine kinase - Role and significance in Cancer. | name |
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| Tyrosine kinases are important mediators of the signaling cascade, determining key roles in diverse biological processes like growth, differentiation, metabolism and apoptosis in response to external and internal stimuli. Recent advances have implicated the role of tyrosine kinases in the pathophysiology of cancer. Though their activity is tightly regulated in normal cells, they may acquire transforming functions due to mutation(s), overexpression and autocrine paracrine stimulation, leading to malignancy. Constitutive oncogenic activation in cancer cells can be blocked by selective tyrosine kinase inhibitors and thus considered as a promising approach for innovative genome based therapeutics. The modes of oncogenic activation and the different approaches for tyrosine kinase inhibition, like small molecule inhibitors, monoclonal antibodies, heat shock proteins, immunoconjugates, antisense and peptide drugs are reviewed in light of the important molecules. As angiogenesis is a major event in cancer growth and proliferation, tyrosine kinase inhibitors as a target for anti-angiogenesis can be aptly applied as a new mode of cancer therapy. The review concludes with a discussion on the application of modern techniques and knowledge of the kinome as means to gear up the tyrosine kinase drug discovery process. | description |
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| Paul, Manash K, Mukhopadhyay, Anup K | authors |
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| Chloroplast Biogenesis 49 : Differences among Angiosperms in the Biosynthesis and Accumulation of Monovinyl and Divinyl Protochlorophyllide during Photoperiodic Greening. | name |
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| Various angiosperms differed in their monovinyl and divinyl protochlorophyllide biosynthetic capabilities during the dark and light phases of photoperiodic growth. Some plant species such as Cucumis sativus L., Brassica juncea (L.) Coss., Brassica kaber (DC.) Wheeler, and Portulaca oleracea L. accumulated mainly divinyl protochlorophyllide at night. Monocotyledonous species such as Avena sativa L., Hordeum vulgare L., Triticum secale L., Zea mays L., and some dicotyledonous species such as Phaseolus vulgaris L., Glycine max (L.) Merr., Chenopodium album L., and Lycopersicon esculentum L. accumulated mainly monovinyl protochlorophyllide at night.Under low light intensities meant to simulate the first 60 to 80 minutes following daybreak divinyl protochlorophyllide appeared to contribute much more to chlorophyll formation than monovinyl protochlorophyllide in species such as Cucumis sativus L. Under the same light conditions, species which accumulated mainly monovinyl protochlorophyllide at night appeared to form chlorophyll preferably via monovinyl protochlorophyllide.THESE RESULTS WERE INTERPRETED IN TERMS OF: (a) a differential contribution of monovinyl and divinyl protochlorophyllide to chlorophyll formation at daybreak in various plant species; and (b) a differential regulation of the monovinyl and divinyl protochlorophyllide biosynthetic routes by light and darkness. | description |
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| Carey, E E, Rebeiz, C A | authors |
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| Analysis of Guard Cell Viability and Action in Senescing Leaves of Nicotiana glauca (Graham), Tree Tobacco. | name |
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| In an attempt to determine whether low epidermal conductances to water vapor diffusion of senescing leaves were caused by internal changes in guard cells or by factors external to guard cells, stomatal behavior was examined in intact senescing and nonsenescing leaves of Nicotiana glauca (Graham), tree tobacco, grown in the field or in an environmental chamber. Conductances of senescing leaves were 5 to 10% of the maximum conductances of nonsenescing leaves of the same plant, yet guard cell duplexes isolated from epidermal peels of senescing leaves developed full turgor in the light in solutions containing KCl, and sodium cobaltinitrite staining showed that K(+) accumulated as turgor developed. Ninety-five per cent of the guard cells isolated from senescing leaves concentrated neutral red and excluded trypan blue. Intercellular leaf CO(2) concentrations of senescing and nonsenescing leaves of chamber-grown plants were not significantly different (about 240 microliters per liter), but the potassium contents of adaxial and abaxial epidermes of senescing leaves taken from plants grown in the field were less than half those of nonsenescing leaves. We conclude that guard cells do not undergo the orderly senescence process that characteristically takes place in mesophyll tissue during whole-leaf senescence and that the reduced conductances of senescing leaves are produced by factors external to guard cells. | description |
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| Ozuna, R, Yera, R, Ortega, K, Tallman, G | authors |
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| Relationship between Stress-Induced ABA and Proline Accumulations and ABA-Induced Proline Accumulation in Excised Barley Leaves. | name |
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| When excised second leaves from 2-week-old barley (Hordeum vulgare var Larker) plants were incubated in a wilted condition, abscisic acid (ABA) levels increased to 0.6 nanomole per gram fresh weight at 4 hours then declined to about 0.3 nanomole per gram fresh weight and remained at that level until rehydrated. Proline levels began to increase at about 4 hours and continued to increase as long as the ABA levels were 0.3 nanomole per gram fresh weight or greater. Upon rehydration, proline levels declined when the ABA levels fell below 0.3 nanomole per gram fresh weight.Proline accumulation was induced in turgid barley leaves by ABA addition. When the amount of ABA added to leaves was varied, it was observed that a level of 0.3 nanomole ABA per gram fresh weight for a period of about 2 hours was required before proline accumulation was induced. However, the rate of proline accumulation was slower in ABA-treated leaves than in wilted leaves at comparable ABA levels. Thus, the threshold level of ABA for proline accumulation appeared to be similar for wilted leaves where ABA increased endogenously and for turgid leaves where ABA was added exogenously. However, the rate of proline accumulation was more dependent on ABA levels in turgid leaves to which ABA was added exogenously than in wilted leaves.Salt-induced proline accumulation was not preceded by increases in ABA levels comparable to those observed in wilted leaves. Levels of less than 0.2 nanomole ABA per gram fresh weight were measured 1 hour after exposure to salt and they declined rapidly to the control level by 3 hours. Proline accumulation commenced at about 9 hours. Thus, ABA accumulation did not appear to be involved in salt-induced proline accumulation. | description |
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| Stewart, C R, Voetberg, G | authors |
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| Effect of calmodulin antagonists on auxin-induced elongation. | name |
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| Coleoptile segments of oat (Avena sativa var Cayuse) and corn (Zea mays L. var Patriot) were incubated in different concentrations of calmodulin antagonists in the presence and absence of alpha-naphthaleneacetic acid. The calmodulin antgonists (chlorpromazine (CP), trifluoperazine, and fluphenazine) inhibited the auxin-induced elongation at 5 to 50 micromolar concentrations. Chlorpromazine sulfoxide, an analog of chlorpromazine, did not have significant effect on the elongation of oat and corn coleoptiles. A specific inhibitor of calmodulin N-(6-aminohexyl)5-chloro-1-naphthalenesulfonamide hydrochloride (W-7, a naphthalenesulfonamide derivative) inhibited coleoptile elongation, while its inactive analog N-(6-aminohexyl)-1-naphthalenesulfonamide hydrochloride (W-5) was ineffective at similar concentrations. During a 4-hour incubation period, coleoptile segments accumulated significant quantities of (3)H-CP. About 85 to 90% of auxin-induced growth was recovered after 4 hours of preincubation with CP or 12 hours with W-7 and transferring coleoptiles to buffer containing NAA. Leakage of amino acids from coleoptiles increased with increasing concentration of CP, showing a rapid and significant increase above 20 micromolar CP. The amount of amino acids released in the presence of W-7 and W-5 was significantly lower than the amount released in the presence of CP. Both W-5 and W-7 increased amino acid release but only W-7 inhibited auxin-induced growth. Calmodulin activity measured by phosphodiesterase activation did not differ significantly between auxin-treated and control coleoptile segments. These results suggest the possible involvement of calmodulin in auxin-induced coleoptile elongation. | description |
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| Raghothama, K G, Mizrahi, Y, Poovaiah, B W | authors |
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| Starch Branching Enzymes from Maize : Immunological Characterization using Polyclonal and Monoclonal Antibodies. | name |
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| Spleen cells from mice immunized with starch branching enzymes were fused with cells from the mouse myeloma Sp2/0-AG14 cell line to form hybridomas. Those hybridomas producing antibodies against the branching enzyme were screened by the enzyme-linked immunosorbent assay using purified branching enzyme as the antigen. Three monoclonal cell lines (1A1D7, 1A1C3 and 4D2A9D8) were found to produce antibodies which showed positive enzyme-linked immunosorbent assay reactions with maize branching enzyme I in addition to branching enzymes IIa and IIb. Three other monoclonal cell lines (4D2D10, 4D2F9, and 2A6C12) were also selected which were found to produce antibodies showing positive enzyme-linked immunosorbent assay reactions with branching enzymes IIa and IIb only.Amino acid composition and peptide maps obtained after trypsin or chymotrypsin digestion show that there is no difference between branching enzyme IIa and IIb but they are significantly different from branching enzyme I which, along with immunological data, suggests that only two forms of starch branching enzyme may be present in maize kernels.Immunological cross-reaction was also found between the starch branching enzyme from maize kernels and the glycogen branching enzyme from Escherichia coli using polyclonal antibodies against starch branching enzyme I or IIa and IIb or E. coli glycogen branching enzyme, suggesting some immunological similarities between maize starch branching enzymes and E. coli glycogen branching enzyme. | description |
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| Singh, B K, Preiss, J | authors |
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| A novel method of natural cryoprotection : intracellular glass formation in deeply frozen populus. | name |
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| Correlating measurements from differential scanning calorimetry, freeze-fracture freeze-etch electron microscopy, and survival of twigs after two-step cooling experiments, we provide strong evidence that winter-hardened Populus balsamifera v. virginiana (Sarg.) resists the stresses of freezing below -28 degrees C by amorphous solidification (glass formation) of most of its intracellular contents during slow cooling (</=5 degrees C per hour). It is shown that other components of the intracellular medium go through glass transitions during slow cooling at about -45 degrees C and below -70 degrees C. This ;three glass' model was then used to predict the results of differential scanning calorimetry, freeze-fracture freeze-etch electron microscopy, and biological experiments. This model is the first definitive explanation for the resistance of a woody plant to liquid N(2) temperatures even if quench cooling (1200 degrees C per minute) begins at temperatures as high as -20 degrees C and warming is very slow (</=5 degrees C per hour). It is also the first time high temperature natural intracellular glass formation has been demonstrated. | description |
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| Hirsh, A G, Williams, R J, Meryman, H T | authors |
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| Enzymic Properties of Ribulose-1,5-bisphosphate Carboxylase/Oxygenase Purified from Rice Leaves. | name |
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| The enzymic properties of ribulose 1,5-bisphosphate (RuBP) carboxylase/oxygenase purified from rice (Oryza sativa L.) leaves were studied. Rice RuBPcarboxylase, activated by preincubation with CO(2) and Mg(2+) like other higher plant carboxylases, had an activation equilibrium constant (K(c)K(Mg)) of 1.90 x 10(5) to 2.41 x 10(5) micromolar(2) (pH 8.2 and 25 degrees C). Kinetic parameters of carboxylation and oxygenation catalyzed by the completely activated enzyme were examined at 25 degrees C and the respective optimal pHs. The K(m)(CO(2)), K(m)(RuBP), and V(max) values for carboxylation were 8 micromolar, 31 micromolar, and 1.79 units milligram(-1), respectively. The K(m)(O(2)), K(m)(RuBP), and V(max) values for oxygenation were 370 micromolar, 29 micromolar, and 0.60 units milligram(-1), respectively.Comparison of rice leaf RuBP carboxylase with other C(3) plant carboxylases showed that it had a relatively high affinity for CO(2) but the lowest catalytic turnover number (V(max)) among the species examined. | description |
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| Makino, A, Mae, T, Ohira, K | authors |
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| Correct targeting of the bean storage protein phaseolin in the seeds of transformed tobacco. | name |
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| The storage protein phaseolin accumulates during seed development in protein bodies in cotyledons of the common bean Phaseolus vulgaris. Hall et al. (In L Van Vloten-Doting, TC Hall, eds, Molecular Form and Function of the Plant Genome, 1985 Plenum Press, In press) recently reported the expression of a gene coding for phaseolin and the accumulation of phaseolin protein in developing seeds of tobacco plants regenerated from transformed callus cells. The protein did not accumulate in other organs of the plants. Mature seeds from normal and transformed tobacco plants were obtained and the subcellular distribution of phaseolin in the seeds was examined using both light and electron microscopic immunocytochemical methods. Phaseolin was found in six of seven transformed tobacco embryos examined, but was present in only one endosperm of five. When present, phaseolin was located exclusively in the protein bodies of the embryonic and endospermic cells. Furthermore, phaseolin was restricted solely to the amorphous matrix of the protein bodies and was excluded from the globoid and proteinaceous crystalloid components of these organelles. The subcellular location of phaseolin in seeds from transformed tobacco plants is similar to that seen in mature seeds of the common bean indicating that in the transformed cells the protein is targeted to the right subcellular compartment. | description |
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| Greenwood, J S, Chrispeels, M J | authors |
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| Surface properties of right side-out plasma membrane vesicles isolated from barley roots and leaves. | name |
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| Highly purified plasma membrane vesicles were obtained from roots and leaves of 7-day-old light-grown barley (Hordeum vulgare L. cv Kristina) seedlings by partitioning of crude microsomal fractions in a dextran-polyethylene glycol two-phase system. Sodium dodecylsulfate polyacrylamide gel electrophoresis showed the polypeptide composition of plasma membranes from the two organs to be qualitatively similar, but with different relative amounts of some of the polypeptides. Between 80 and 100% of the K(+),Mg(2+)-ATPase activity was latent indicating that the vesicles were sealed and right side-out. The isoelectric points of the outer surface of root and leaf plasma membranes as determined by cross-partitioning were similar and quite acidic-about pH 3.6. In contrast, the net negative surface charge density at pH 7.0 as measured by 9-aminoacridine fluorescence differed significantly, being -29 mC.m(-2) for the leaf plasma membrane and only -19 mC.m(-2) for the root plasma membrane. As isolated, both types of plasma membrane vesicles had Ca(2+) and Mg(2+) bound to the outer surface as shown by the combined use of chelators and 9-aminoacridine fluorescence; however, the leaf plasma membrane had a relatively higher proportion of Ca(2+) bound (0.57) than did the root plasma membrane (0.45). This difference probably reflects differences in the in vivo conditions as no chelator was present during the isolation procedure. Also Ni(2+) could bind to the root vesicles as indicated by the effect of Ni(2+) on 9-aminoacridine fluorescence, and by the binding of (63)Ni(2+) (44 nanomoles bound per milligram protein) at 100 micromolar NiCl(2). | description |
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