A new scope for orlistat: Effect of approved anti-obesity drug against experimental microsporidiosis.

As the current therapies for intestinal microsporidiosis are either inconsistent in their efficacies or hampered by several adverse effects, alternative antimicrosporidial agents are being sought. The present study is the first that was designed to evaluate the potency of orlistat, an approved anti-obesity drug, against intestinal microsporidiosis caused by both Enterocytozoon bieneusi and Encephalitozoon intestinalis. Results were assessed through studying fecal and intestinal spore load, intestinal histopathological changes, viability, and infectivity of spores from treated animals. Results showed that orlistat has promising antimicrosporidia potential, with better results in E. intestinalis than E. bieneusi. The animals that received orlistat showed statistically significant decrease in the fecal and intestinal spore load, when compared to the corresponding control infected nontreated mice. The results were insignificant compared to fumagillin and albendazole. Light microscopic examination of stained intestinal sections revealed amelioration of the pathological changes and decreased inflammatory cells detected in the control infected nontreated mice. Spores encountered from stool of orlistat-treated E. bieneusi and E. intestinalis mice showed low viability and significant reduction of infectivity versus their control. Thus, considering the results of the present work, orlistat proved its effectiveness against the intestinal microsporidial infection.

Protection against Fasciola gigantica using paramyosin antigen as a candidate for vaccine production.

Yet no vaccine to protect ruminants against liver fluke infection has been commercialized. In an attempt to develop a suitable vaccine against Fasciola gigantica (F. gigantica) infection in rabbits, using 97 kDa Pmy antigen. It was found that, the mean worm burdens and bile egg count after challenge were reduced significantly by 58.40 and 61.40%, respectively. On the other hand, immunization of rabbits with Pmy induced a significant expression of humoral antibodies (IgM, total IgG, IgG1, IgG2 and IgG4) and different cytokines (IL-6, IL-10, L-12 and TNF-alpha). Among Ig isotypes, IgG2 and IgG4 were most dominant Post-infection (PI) while, recording a low IgG1 level. The dominance of IgG2 and IgG4 suggested late T helper1 (Th1) involvement in rabbit's cellular response. While, the low IgG1 level suggested Th2 response to adult F. gigantica worm Pmy. Among all cytokines, IL-10 was the highest in rabbits immunized with Pmy PI suggesting also the enhancement of Th2 response. It was clear that the native F. gigantica Pmy is considered as a relevant candidate for vaccination against fascioliasis. Also, these data suggested the immunoprophylactic effect of the native F. gigantica Pmy which is mediated by a mixed Th1/Th2 response.

Evaluation of monolithic HPLC columns for various pharmaceutical separations: method transfer from conventional phases and batch to batch repeatability.

Methods developed on conventional particle-packed C18 columns for pilocarpine, propranolol, glibenclamide, glimepiride, insulin and their respective degradation products or related compounds were transferred from the conventional Superspher 100RP-18e column to Chromolith Performance RP-18e columns. All transfers were successful applying the same chromatographic conditions, except for insulin where the acetonitrile content of the mobile phase was reduced by 0.5%. The intraday and interday precisions for both retention time and peak area were evaluated over a wide concentration range. Results were found to be equal, or slightly better on Chromolith Performance with RSD%<1.1% in all cases. Monolithic batch to batch repeatability of both retention time and peak area, compared for monolithic columns from different batches gave an RSD% of less than 1.3%. The separation of each drug and its related products was investigated on monolithic columns at flow rates from 1 to 9 ml/min, and superior resolution was always obtained using monolithic over conventional columns at the same flow rate. A total of seven monolithic columns from four different batches were used in this study.

Comparison of the recovery spread in analytical development and routine quality control--based on the ICH quality guideline Q2B.

In the present study, a simulation was performed for the ICH Q2B guideline for assessing the accuracy. By means of an experimental data set a permutation has been performed to investigate in which interval experimental mean recovery can be expected to scatter just by random effects. A good agreement has been found between the experimental intervals obtained by means of a permutation and the statistically derived confidence intervals. These findings could be confirmed with additionally generated virtual data sets with a true mean of 100% and a true standard deviation of 0.7%.

Evaluation of monolithic C18 HPLC columns for the fast analysis of pilocarpine hydrochloride in the presence of its degradation products.

Monolithic Performance C18 HPLC columns (Chromolith Performance RP-18e, Merck) were applied for the determination of pilocarpine hydrochloride in the presence of its degradation products isopilocarpine, pilocarpic acid and isopilocarpic acid. The method was validated using a set of six monolithic columns and compared to a conventional C18 column. The separation of pilocarpine from its degradation products was investigated on monolithic columns at different flow rates from 1 to 9 ml/min. Superior resolution was obtained using monolithic columns over the conventional C18 column at the same flow rate of 1 ml/min with a total run time of 9 min compared to 13.5 min for the conventional C18 column. Comparable resolution to that obtained in the C18 column (but with better peak symmetry) was obtained at a flow rate of 4 ml/min, although the total run time was reduced to 3.5 min. The precision for both retention time and peak area was investigated over a wide concentration range and found to be equal, or slightly better on Chromolith Performance compared to the conventional column. The overall RSDs% ranged from 0.5% to 1.16% for the conventional column, while for monolithic columns ranged from 0.38% to 0.87% at a flow rate of 1 ml/min and from 0.38% to 0.89% at a flow rate of 4 ml/min. Monolithic column to column reproducibility (n = 6) was measured. The RSDs% ranged from 0.34% to 0.68% for retention time and from 0.3% to 0.94% for peak areas. The detection and quantitation limits on monolithic columns at both flow rates (1 and 4 ml/min) were found to be 0.17 microg/ml and 0.5 microg/ml, compared to 0.31 microg/ml and 1 microg/ml on the conventional column. Monolithic silica rods have also shown the advantage of reducing the time to wash and to re-equilibrate the column. The method showed good linearity and recovery and was found to be suitable for the analysis of pilocarpine hydrochloride formulations.

Impact of hepatitis C on renal transplantation: a long-term study.

Viral hepatitis, especially "C" type (HCV), is an important cause of morbidity and mortality among recipients of renal transplants. In a retrospective long-term study, we reviewed 399 renal transplant patients (133F, 266M) who received 415 kidneys during the past eight-years. We evaluated their HCV infection and liver status. Stored sera (frozen at 80 C) as well as fresh sera collected at the time of transplant and/or at the last observation were used. The donors were cadavers in 386 and living related in 29 renal transplants. The mean follow-up period was 74 months (range 24-124 months). At the time of transplantation 105 recipients (26%) were HCV positive. A the last follow-up 105 (26%) recipients remained positive, 12 (2.8%) seroconverted from negative to positive due to graft and/or blood transfusion and 277 remained negative. Liver biopsy was obtained from 71 to 117 (60.6%) HCV +ve patients. Liver biopsy showed normal histology in 57 (80%) patients, chronic active hepatitis in 42 (59%) patients according to scoring of Knodle's classification. Recurrence of glomerulonephritis in renal allografts occurred in 21 patients. Membrano proliferative glomerulonephritis ( PGN) occurred in nine patients; seven (78%) of them were HCV +ve compared to 29% HCV +ve in the whole group (117/399) (P< 0.001). The actuarial patient and graft survival was similar in HCV-ve and HCV +ve patients. We conclude that HCV is an important cause of liver disease in renal allograft recipients, it might be the cause of recurrence of MPGN, however, it affects neither patients nor graft survival.

Thymus histogenesis in the lizard, Chalcides ocellatus.

Different stages of thymus morphogenesis and thymocyte differentiation have been studied at the ultrastructural level in the lizard, Chalcides ocellatus. On stage 36 of embryonic development, the thymus primordium was composed principally of undifferentiated epithelial cells and some lymphoid stem-cells. From stage 37 to 38, the lymphoid stem-cells differentiate into lymphoblasts and then transform into typical lymphocytes. A clasmotosis phenomenon seems to be involved in this transformation. In the developing cortical regions, lymphoblasts accumulated rapidly, stretching the epithelial cells which become stellate in shape. From stage 39 to 40, a phase of intense proliferation occurs and numerous lymphocytes die in the thymic tissue and are phagocytosed by macrophages. On stage 41, the presence of interdigitating cells in the medullary area completed cortico-medullary differentiation. On neonatal and juvenile lizards, small cortical thymocytes differentiated and the thymus possessed all characteristic of an adult thymus. Thus, at birth, the histogenesis of the lizard thymus was achieved and the only further modification consisted in a gain of weight.

Study of the prevalence of specific human IgG against H. pylori among medical personnel.

The relationship between H. pylori and diseases of gastroduodenal mucosa has been well established. Previous studies suggested a fecal-oral transmission which should place health care personnel who are in close contact with patients at a higher risk. This study was conducted on two groups, the first consisted of 50 medical personnel (28.12 +/- 10.6 years) [34 doctors (30.1 +/- 3.2 years) and 16 nurses (25 years)]. The second consisted of 33 adult healthy volunteers who served as a control group (32.1 +/- 10.6 years). There was high prevalence rates of H. pylori among medical personnel (86%) as well as normal controls (90.9%). H. pylori colonization increased with age in both groups. H. pylori antibody positive doctors had a significantly longer duration of work than H. pylori antibody negative ones (P < 0.05). The prolonged duration of work in medical personnel increased H. pylori antibody positivity. Also, H. pylori antibody positive nurses had a significantly shorter duration of work--i.e. need less time to acquire positivity--than H. pylori antibody positive doctors (P < 0.05). From this study we conclude that H. pylori antibody positive status is very common in both medical personnel and normal population. The longer the duration of exposure to patients in medical personnel the higher the possibility to acquire H. pylori antibody positivity. However, doctors need more years of contact than nurses to acquire H. pylori antibodies.

Characterization of a cell surface adhesion molecule expressed by a subset of developing chick neurons.

We have isolated a 105-kDa membrane glycoprotein expressed by subsets of developing chick neurons. This glycoprotein, identified by the JC7 monoclonal antibody, is present on the surface of axons and cell bodies of developing spinal motor neurons, dorsal root ganglion sensory neurons, sympathetic and parasympathetic neurons, and a small subset of brain neurons. Late in development the JC7 antigen is expressed at high levels on CNS nonneuronal glial-like cells. When attached to latex beads this glycoprotein can mediate homophilic adhesion and when used as a culture substrate stimulates a highly branched pattern of neurite outgrowth from dorsal root ganglion explants. The JC7 antigen appears to be identical to the SC1, BEN, and DM antigens. Its limited distribution, adhesive qualities, and ability to stimulate neurite outgrowth suggest it may play a role in the selective growth of neural processes during development.

Calcium-activated proteolysis of intracellular domains in the cell adhesion molecules NCAM and N-cadherin.

One of the consequences of increased intracellular calcium in response to a variety of physiological stimuli is the calcium activation of cytosolic proteases. Unlike lysosomal proteases with broad specificity, these calcium-activated neutral proteases show limited proteolysis of a restricted set of substrate proteins suggesting they may play a regulatory role in cellular physiology. In this study we show that the neural cell adhesion molecules NCAM-180 and N-cadherin are substrates for such endogenous calcium-activated neutral proteases. In contrast, a third neural cell adhesion molecule G4/L1 was not susceptible to calcium-activated proteolysis. The threshold for activation of NCAM and N-cadherin proteolysis is in the micromolar range of calcium suggesting that NCAM and N-cadherin are substrates for a mu-type calpain (calpain I). The site recognized by this protease is within intracellular domains of NCAM-180 and N-cadherin which are important for their interaction with cytoskeletal components. These results suggest that calcium-activated proteolysis at these sites in vivo could disrupt the linkage between extracellular ligand binding to these adhesion molecules and the normal intracellular effectors of such extracellular binding events.

Immunological changes during pregnancy in the viviparous lizard, Chalcides ocellatus.

Splenic cells from pregnant and non-pregnant viviparous lizards (Chalcides ocellatus) were stimulated in vitro with the mitogens, concanavalin A (Con A), phytohemagglutinin (PHA) and Escherichia coli lipopolysaccharide (LPS). Cell cultures from pregnant animals were significantly less responsive to Con A and PHA than comparable cultures from non-pregnant animals. The response was depressed during the first period of pregnancy and remained low in magnitude until parturition. By contrast, the response of maternal splenic cells to LPS was reduced in pregnant lizards only during advanced pregnancy. The drastic decrease in mitogenic responsiveness was associated with marked involution of the maternal spleen. These findings strongly suggest that pregnancy impairs the immunoreactivity of viviparous lizards. Possible mechanisms for this impairment and the relationship to circulating levels of sex hormones are discussed.

In vitro effect of aflatoxin B1 on the transcriptional activity of DNA template, chromatin and soluble DNA-dependent RNA polymerases in buffalo liver.

The effect of aflatoxin B1 on the DNA template and DNA-dependent RNA polymerases in buffalo liver was studied. Aflatoxin B1 inhibited both Mg2+- and Mn2+-activated RNA polymerases in a dose-dependent manner. At 10 micrograms the inhibition of both enzymes was almost complete. The inhibitory effect on the solubilized enzymes was higher than the chromatin-bound, suggesting a direct effect at the enzyme level. On the other hand, incubating DNA or deoxyribonucleoprotein (DNP) with 2 micrograms aflatoxin reduces its transcriptional capacity with a greater effect on the Mg2+-activated RNA polymerase than the Mn2+-activated enzyme. These results suggest that aflatoxin B1 inhibits in vitro transcription in buffalo liver at both enzyme and template levels.

Isolation, purification and characterization of enzyme(s) responsible for conversion of sterigmatocystin to aflatoxin B1.

The cell-free extract prepared from Aspergillus flavus ATCC 5517/A 228 showed activity in converting sterigmatocystin to aflatoxin B1. The extract was purified on Ultrogel AcA-54 and resulted in ten protein peaks, one of which (peak VI) showed activity in sterigmatocystin conversion. The protein in this peak gave one protein band using polyacrylamide gel (PAG)-disc electrophoresis. For further purification, protein(s) in peak VI were applied on DEAE-Sephadex A-50 and two protein peaks were detected. Only one peak showed enzyme activity which showed homogeneity as one band on PAGE and sodium dodecyl sulphate (SDS)-PAGE. The optimum temperature for the enzyme activity was 28 degrees C and the optimum pH was 8. The maximum conversion resulted from the action of 0.6 mg enzyme protein on 48 X 10(-8) mol sterigmatocystin. Zn2+, Co2+ and Mn2+ enhanced the enzyme activity, while ethylenediaminetetraacetic acid, parahydroxymercuric benzoate and phenylmethylsulphonic fluoride inhibited the enzyme activity in a dose-dependent manner. Amino-acid analysis showed the presence of 22 amino acids, three of which are unknown. The enzyme has a molecular weight of 64,000 daltons (by gel filtration) and 70,000 daltons (by SDS-PAGE).

Detection of Thy-1+ cells in the developing thymus of the lizard, Chalcides ocellatus.

The ontogenic appearance of Thy-1+ cells was studied in the thymus of the lizard, Chalcides ocellatus, by indirect immunofluorescence using a rabbit antibrain antiserum produced against surface determinants shared by both the thymus and the brain lizards. Thymic Thy-1+ cells were first detected at stage 37. They increased rapidly reaching adult numbers by stage 41. Apparently Thy-1+ cells differentiate from lymphoid precursors arriving at the thymus analage before stage 37. The results are compared to those found during the differentiation of Thy-1+ thymocyte in murine thymus and agree with former reports on the thymic development in Chalcides using rabbit antisera against adult thymocyte marker(s).

Ontogeny of con A responsiveness and mixed leucocyte reactivity in the lizard, Chalcides ocellatus.

The immune system of phylogenetically key animals will contribute significantly to our understanding of the evolution of immune response in higher vertebrates. Reptiles, being evolutionary precursors of both birds and mammals, represent a pivotal group and thus a study of their immune system is of special significance. Here we described the emergence of T-cell immune capability in the viviparous lizard (Chalcides ocellatus) throughout embryonic development (stages 36-41 of Zada and El Deeb, 1984) and in newborns. The response of embryonic thymocytes (5 X 10(5) cells/ml) to Con A (5 micrograms/ml in culture) was first detected at stages 36-37, increased gradually during successive stages and then declined at birth to yield low responses in newborn lizards. In addition, embryonic thymocytes cultured in two-way MLR, using several combination sets, were significantly responsive at all stages. Our results reveal a degree of immunological T-cell maturation during reptitilian embryonic life which is similar to results in amphibians and mammals, but not clear with respect to fish and birds where comparative information still somewhat limited.