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991.
Mukherjee K Chava AK Mandal C Dey SN Kniep B Chandra S Mandal C 《Journal of cellular biochemistry》2008,105(3):724-734
We have previously demonstrated induction of O-acetylated sialoglycoproteins on lymphoblasts of childhood acute lymphoblastic leukaemia (ALL). These molecules promote survival of lymphoblasts by preventing apoptosis. Although O-acetylated sialoglycoproteins are over expressed, the status of O-acetylation of gangliosides and their role in lymphoblasts survival remains to be explored in ALL patients. Here, we have observed enhanced levels of 9-O-acetylated GD3 (9-O-AcGD3) in the lymphoblasts of patients and leukaemic cell line versus disialoganglioside GD3 in comparison to the normal cells. Localization of GD3 and 9-O-AcGD3 on mitochondria of patient's lymphoblasts has been demonstrated by immuno-electron microscopy. The exogenous administration of GD3-induced apoptosis in lymphoblasts as evident from the nuclear fragmentation and sub G0/G1 apoptotic peak. In contrast, 9-O-AcGD3 failed to induce such apoptosis. We further explored the mitochondria-dependent pathway triggered during GD3-induced apoptosis in lymphoblasts. GD3 caused a time-dependent depolarization of mitochondrial membrane potential, release of cytochrome c and 7.4- and 8-fold increased in caspase 9 and caspase 3 activity respectively. However, under identical conditions, an equimolar concentration of 9-O-AcGD3 failed to induce similar effects. Interestingly, 9-O-AcGD3 protected the lymphoblasts from GD3-induced apoptosis when administered in equimolar concentrations simultaneously. In situ de-O-acetylation of 9-O-AcGD3 with sodium salicylate restores the GD3-responsiveness to apoptotic signals. Although both GD3 and 9-O-acetyl GD3 localize to mitochondria, these two structurally related molecules may play different roles in ALL-disease biology. Taken together, our results suggest that O-acetylation of GD3, like that of O-acetylated sialoglycoproteins, might be a general strategy adopted by leukaemic blasts towards survival in ALL. 相似文献
992.
Background
Scapular hypoplasia, elevation, and rotation (SHEAR) deformity and posterior subluxation of the humeral head are common tertiary sequelae of obstetric brachial plexus injuries (OBPI). Interpretations of images from bilateral computed tomography (CT) scans of the upper extremities are critical to the diagnosis and treatment plan for patients with these bony deformities resulting from OBPI.Methods
We conducted a retrospective study to investigate the accuracy of radiologic reports in the diagnosis of SHEAR or posterior subluxation of the humeral head in OBPI patients. CT studies from 43 consecutive patients over a 33-month period were used in the study. For each patient, we compared the results from the radiologic report to those from a clinical examination given by the attending surgeon and to measurements taken from the CT studies by biomedical researchers.Results
A comparison of SHEAR measured from the 3-D CT images to the diagnoses from the radiologists, revealed that only 40% of the radiological reports were accurate. However, there was a direct correlation between the use of the 3-D CT images and an accurate SHEAR diagnosis by the radiologists (p < 0.0001). When posterior subluxation was measured in the affected and contralateral shoulders, 93% of the patients that had greater than a 10% difference between the two shoulders did not have their deformity diagnosed. The radiological reports diagnosed 17% of these patients with a 'normal' shoulder. Only 5% of the reports were complete, accurately diagnosing SHEAR in addition to posterior subluxation.Conclusion
Due to the low incidence rate of OBPI, many radiologists may be unfamiliar with the sequelae of these injuries. It is therefore critical that radiologists are made aware of the importance of an accurate measurement and diagnosis of the SHEAR deformity. Due to their lack of completeness, the radiological reports in this study did not significantly contribute to the clinical care of the patients. In order for OBPI patients to receive the highest standard of care, the final diagnosis from their radiological imaging should be deferred to a brachial plexus specialist who is experienced with these types of injuries. 相似文献993.
Dhali A Karunakaran M Mech A Nath N Prakash B Rajkhowa C Mishra DP 《Animal : an international journal of animal bioscience》2008,2(6):879-882
The study describes the standardization of a suitable semen cryopreservation protocol for the first time in mithun (Bos frontalis) and birth of the first mithun calf through artificial insemination. The semen samples were collected from adult bulls through the rectal massage method and cryopreserved in liquid nitrogen using tris-egg yolk-glycerol diluent. The diluted semen samples were packaged in 0.50 ml straws and kept at 5°C for 4 h for equilibration. Following the equilibration, the straws were frozen into liquid nitrogen vapour for 10 min and then plunged into liquid nitrogen for storage. It was observed that the progressive motility (%) decreased significantly (P < 0.01) in cryopreserved semen (43.3 ± 4.1) compared with fresh samples (76.6 ± 3.3). The percentages of live spermatozoa (P < 0.01) and spermatozoa with intact acrosome (P < 0.05) also decreased significantly in cryopreserved semen (54.0 ± 3.3 and 64.6 ± 5.3) compared with fresh samples (79.3 ± 2.6 and 85.3 ± 1.8). Simultaneously, the total morphological abnormality (%) was found to be significantly (P < 0.01) higher in cryopreserved samples (15.46 ± 2.68) than in fresh semen (3.85 ± 0.63). A total of three mithun cows were inseminated using the cryopreserved semen. All the cows conceived following insemination and gave birth to healthy calves. The study revealed that mithun semen can be cryopreserved efficiently using tris-egg yolk-glycerol diluent, which can be further used for artificial insemination. 相似文献
994.
An efficient and cost effective non-conventional adsorbent has been prepared from seaweed Laminaria japonica by crosslinking with epichlorohydrin. Its adsorption behavior for trivalent and divalent metal ions was studied and it was found to exhibit excellent selectivity towards several metal ions. As a typical example, binary mixture of Pb(II) and Zn(II) was studied by using a packed column, indicating that the Pb(II) ion can be easily separated from its mixture with a concentration factor of 74 times. The maximum adsorption capacity for Pb(II), Cd(II), Fe(III) was found to be 1.35, 1.1, 1.53 mol kg(-1), respectively, while 0.8 7 mol kg(-1) for both La(III) and Ce(III) from the single metal ion solution according to the adsorption isotherm. The obtained values are comparable to the commercially available synthetic chelating resins. 相似文献
995.
The identification of MHC restricted epitopes is an important goal in peptide based vaccine and diagnostic development. As
wet lab experiments for identification of MHC binding peptide are expensive and time consuming, in silico tools have been
developed as fast alternatives, however with low performance. In the present study, we used IEDB training and blind
validation datasets for the prediction of peptide binding to fourteen human MHC class I and II molecules using Gibbs motif
sampler, weight matrix and artificial neural network methods. As compare to MHC class I predictor based on sequence
weighting (Aroc=0.95 and CC=0.56) and artificial neural network (Aroc=0.73 and CC=0.25), MHC class II predictor based on
Gibbs sampler did not perform well (Aroc=0.62 and CC=0.19). The predictive accuracy of Gibbs motif sampler in identifying
the 9-mer cores of a binding peptide to DRB1 alleles are also limited (40¢), however above the random prediction (14¢).
Therefore, the size of dataset (training and validation) and the correct identification of the binding core are the two main
factors limiting the performance of MHC class-II binding peptide prediction. Overall, these data suggest that there is
substantial room to improve the quality of the core predictions using novel approaches that capture distinct features of
MHC-peptide interactions than the current approaches. 相似文献
996.
997.
Combined dark and photo-fermentation was carried out to study the feasibility of biological hydrogen production. In dark fermentation,
hydrogen was produced by Enterobacter cloacae strain DM11 using glucose as substrate. This was followed by a photo-fermentation process. Here, the spent medium from the
dark process (containing unconverted metabolites, mainly acetic acid etc.) underwent photo-fermentation by Rhodobacter sphaeroides strain O.U.001 in a column photo-bioreactor. This combination could achieve higher yields of hydrogen by complete utilization
of the chemical energy stored in the substrate. Dark fermentation was studied in terms of several process parameters, such
as initial substrate concentration, initial pH of the medium and temperature, to establish favorable conditions for maximum
hydrogen production. Also, the effects of the threshold concentration of acetic acid, light intensity and the presence of
additional nitrogen sources in the spent effluent on the amount of hydrogen produced during photo-fermentation were investigated.
The light conversion efficiency of hydrogen was found to be inversely proportional to the incident light intensity. In a batch
system, the yield of hydrogen in the dark fermentation was about 1.86 mol H2 mol−1 glucose; and the yield in the photo-fermentation was about 1.5–1.72 mol H2 mol−1 acetic acid. The overall yield of hydrogen in the combined process, considering glucose as the preliminary substrate, was
found to be higher than that in a single process. 相似文献
998.
Mitra BN Yasuda T Kobayashi S Saito-Nakano Y Nozaki T 《Cell motility and the cytoskeleton》2005,62(2):84-99
Phagocytosis plays an important role in the pathogenicity of the intestinal protozoan parasite Entamoeba histolytica. We compared the morphology of phagosomes and the kinetics of phagosome maturation using conventional light and electron microscopy and live imaging with video microscopy between the virulent E. histolytica and the closely-related, but non-virulent E. dispar species. Electron micrographs showed that axenically cultivated trophozoites of the two Entamoeba species revealed morphological differences in the number of bacteria contained in a single phagosome and the size of phagosomes. Video microscopy using pH-sensitive fluorescein isothiocynate-conjugated yeasts showed that phagosome acidification occurs within 2 min and persists for >12 h in both species. The acidity of phagosomes significantly differed between two species (4.58 +/- 0.36 or 5.83 +/- 0.38 in E. histolytica or E. dispar, respectively), which correlated well with the differences in the kinetics of degradation of promastigotes of GFP-expressing Leishmania amazonensis. The acidification of phagosomes was significantly inhibited by a myosin inhibitor, whereas it was only marginally inhibited by microtubules or actin inhibitors. A specific inhibitor of vacuolar ATPase, concanamycin A, interrupted both the acidification and degradation in phagosomes in both species, suggesting the ubiquitous role of vacuolar ATPase in the acidification and degradation in Entamoeba. In contrast, inhibitors against microtubules or cysteine proteases (CP) showed distinct effects on degradation in phagosomes between these two species. Although depolymerization of microtubules severely inhibited degradation in phagosomes of E. histolytica, it did not affect degradation in E. dispar. Similarly, the inhibition of CP significantly reduced degradation in phagosomes of E. histolytica, but not in E. dispar. These data suggest the presence of biochemical or functional differences in the involvement of microtubules and proteases in phagosome maturation and degradation between the two species. 相似文献
999.
Effect of acute, chronic-predictable and chronic-unpredictable stress on memory and acetylcholinesterase (AChE) was investigated in rats. The animals were subjected to 3 type of stressors--(1) acute immobilization stress, (2) chronic-predictable stress i.e., immobilization daily for 5 consecutive days and (3) chronic-unpredictable stress that included reversal of light/dark cycle, over-night fasting, forced-swimming, immobilization and forced exercise in random unpredictable manner daily for 5 consecutive days. Learning and memory function was studied by single trial Passive avoidance test. AChE activity was assayed spectrophotometrically in the detergent (DS) and salt (SS) soluble fractions in different brain regions. Learning was obtained in acute and chronic-predictable stress groups but not in chronic-unpredictable group. Acute, chronic-predictable and chronic-unpredictable stress caused significant decrease in AChE activity in the DS fraction of cortex, hippocampus and hypothalamus as compared to control. Results indicate that AChE in DS fraction is predominantly affected in stressed and stressed-trained group but cognition is affected only by chronic-unpredictable stress. In acute and chronic-predictable groups the decreased AChE activity in the hippocampal DS fraction during learning may be responsible to maintain cognitive function by enhancing the cholinergic activity. 相似文献
1000.
Mandal A Chakraborti T Choudhury R Ghosh B Ghosh AN Das S Chakraborti S 《Molecular and cellular biochemistry》2005,270(1-2):79-87
Treatment of microsomes (preferentially enriched with endoplasmic reticulum) isolated from bovine pulmonary artery smooth muscle tissue with H2O2 (1 mM) markedly stimulated matrix metalloproteinase activity and also inhibited Na+ dependent Ca2+ uptake. Electron micrograph revealed that H2O2 (1 mM) does not cause any damage to the microsomes. MMP-2 and TIMP-2 were determined to be the ambient protease and corresponding antiprotease of the microsomes. Pretreatment with vitamin E (1 mM) and TIMP-2 (50 g/ml) reversed the effect produced by H2O2 (1 mM) on Na+ dependent Ca2+ uptake in the microsomes. However, H2O2 (1 mM) caused changes in MMP-2 activity and Na+ dependent Ca2+ uptake were not reversed upon pretreatment of the microsomes with a low concentration of 5 g/ml of TIMP-2 which otherwise reversed MMP-2 (1 g/ml) mediated increase in 14C-gelatin degradation and inhibition of Na+ dependent Ca2+ uptake. Combined treatment of the microsomes with a low dose of MMP-2 (0.5 g/ml) and H2O2 (0.5 mM) inhibited Na+ dependent Ca2+ uptake in the microsomes compared to the respective low dose of either of them. Direct treatment of TIMP-2 (5 g/ml) with H2O2 (1 mM) abolished the inhibitory effect of the inhibitor on 14C-gelatinolytic activity elicited by 1 g/ml of MMP-2. Thus, one of the mechanisms by which H2O2 activates MMP-2 could be due to inactivation of TIMP-2 by the oxidant. The resulting activation of MMP-2 subsequently inhibits Na+ dependent Ca2+ uptake in the microsomes. (Mol Cell Biochem 270: 79–87, 2005) 相似文献