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Biomedical subjects

S M Saleh

Publications and source records attributed to S M Saleh.

At least 19 recordsLinked to original sources
PubMed2001

PKC-gamma phosphorylation of connexin 46 in the lens cortex.

PURPOSE: To identify the role of PKC-gamma in control of and phosphorylation of connexin 46 (Cx46) in the lens cortex. METHODS: The association between PKC-gamma and Cx46 was determined by co-immunoprecipitation from whole lens. Phosphorylation of Cx46 and activity of PKC-gamma were determined using Western blots, PKC activity assays, and inhibition of PKC activity by addition of isoform-specific PKC pseudosubstrate inhibitors. RESULTS: Co-localization of PKC-gamma and Cx46 was observed in the bow regions and cortical regions of rat lens. PKC-gamma was not observed in the nuclear region and Cx46 was not observed in the epithelial layer. PKC-alpha was not found in lens cortex or nuclear regions. PKC-gamma could be co-immunoprecipitated with Cx46 from lens cortical regions. Cx46 was phosphorylated on both serine and threonine. No tyrosine phosphorylation was observed. The PKC-gamma specific pseudosubstrate inhibitor caused a 73% inhibition of serine phosphorylation on Cx46 at 1 microM, and, 36% inhibition of threonine phosphorylation at the same concentration. Inhibition of phosphorylation of Cx46 with PKC-alpha pseudosubstrate inhibitor was not observed. CONCLUSIONS: PKC-gamma may phosphorylate Cx46, primarily on serine in whole lens. A role for PKC-gamma in control of lens cortical gap junctions is suggested.

Animals↗
PubMed2001

Src-class kinases act within the agrin/MuSK pathway to regulate acetylcholine receptor phosphorylation, cytoskeletal anchoring, and clustering.

Synaptogenesis at the neuromuscular junction requires agrin-induced stable localization of acetylcholine receptors (AChRs) at the endplate. The effects of agrin are transduced by the muscle-specific receptor tyrosine kinase (MuSK). This study provides evidence that Src-class protein tyrosine kinases mediate the effects of agrin-activated MuSK to regulate clustering and anchoring of AChRs in skeletal muscle. MuSK was complexed with both Src and Fyn in the C2 mouse muscle cell line. These associations were enhanced by agrin and by increasing protein tyrosine phosphorylation with pervanadate. Coupling between MuSK and the Src-class kinases in vivo appeared to be caused by a phosphotyrosine-SH2 domain interaction because binding of MuSK to the SH2 domains of Fyn and Src in vitro was specific, enhanced by phosphorylation, and dependent on MuSK autophosphorylation. In addition, Src and Fyn phosphorylated MuSK. AChR phosphorylation, stimulated by agrin or pervanadate, was inhibited by blocking Src-class kinases with PP1. Furthermore, agrin-induced clustering and cytoskeletal anchoring of AChRs was dependent on Src-family kinases. These data support the conclusion that Fyn and Src act downstream of MuSK to regulate the stable localization of AChRs at the neuromuscular endplate during agrin-induced synaptogenesis.

Agrin↗
PubMed1995

High prevalence of hepatitis C in Egyptian patients with chronic liver disease.

The highest prevalence rates of hepatitis C virus infection in the world have been recently reported among Egyptian blood donors and frequent recipients of transfusions and other blood products. This is the first report, however, demonstrating hepatitis C as the most frequent association with chronic liver disease in Egypt. Of 1023 patients referred to the Liver Institute in Menoufia governorate for evaluation of chronic liver disease, 752 (73.5%) had antibodies to hepatitis C compared with 168 (16.4%) with hepatitis B surface antigen. Hepatitis C antibody was more common in patients with active schistosomiasis and patients without hepatitis B surface antigenaemia. Of 100 patients having liver biopsies, histological findings consistent with chronic viral hepatitis or its complications were found in 89 and antibody to hepatitis C was present in 75 (84.3%) of these patients with chronic hepatitis, active cirrhosis or hepatocellular carcinoma. These data pointing to the importance of hepatitis C as a cause of chronic liver disease in Egypt emphasise the necessity of studies delineating its routes of transmission in this country.

Chronic Disease↗
PubMed1994

Hepatitis C virus-polymerase chain reaction of routinely processed liver biopsies.

The aim of the study was to evaluate the specificity and sensitivity of detection of hepatitis C virus (HCV)-RNA in formalin-fixed paraffin-embedded (FFPE) liver biopsies by polymerase chain reaction (PCR). Routinely processed FFPE diagnostic needle liver biopsies as well as stored serum samples from 43 patients with liver disease were tested for HCV-RNA by reverse transcription-nested PCR using the same sets of primers and following strict anticontamination measures. Twenty-nine cases were positive and 14 were negative for serum HCV-RNA. Tissue HCV-RNA was detected in 17 out of the 29 serum HCV-RNA-positive cases but not in any of the 14 serum HCV-RNA-negative cases. Compared to serum-PCR, tissue-PCR was 100% specific, 58.6% sensitive, and 72% efficient. HCV-RNA was detected more frequently in biopsies stored for less than 1 year, than in those stored for more than 1 year (P = 0.046). In biopsies stored for up to 1 year detection of HCV-RNA by PCR was 81.8% sensitive and 90.9% efficient. Short (< 0.5 cm) liver biopsies were as sufficient for nucleic acid extraction and amplification as long (> 0.5 cm) ones. It is concluded that following strict anticontamination measures, HCV-RNA detection by PCR in routinely fixed, processed, and stored diagnostic liver biopsies provides a valuable adjunct to diagnosis of HCV infection. In this study, this option was free from contamination problems, even though routine batch histological processing schedules were used.

Base Sequence↗
PubMed1993

Evaluation of direct and indirect methods in diagnosis of chronic intestinal schistosomiasis in Menoufia Governorate.

A comparative study of Kato thick smear method, modified Ritchie concentration technique (MRCT), rectal snip biopsy and indirect haemagglutination (IHA) test were done on fifty patients with chronic intestinal schistosomiasis from Menoufia governorate, an area of Nile Delta endemic for schistosomiasis. Study revealed that a single kato-preparation was not sufficient to determine correctly the prevalence of Schistosoma mansoni infection particularly in chronic cases (22%), the accuracy was maximized by examining stool samples obtained from the same patient by MRCT (46%). Rectal snip biopsy and IHA test showed high positivity rate of 80% and 74% respectively. It is recommended to combine stool examination by MRCT with either rectal snip or IHA test according to the condition of patient as the former can not be performed on routine basis.

Adolescent↗
PubMed1992

Application of Corynebacterium cutis lysate as an immune stimulant in cattle.

An ultrasonicated lysate of Corynebacterium cutis (Ultracorn, Virbac, France) was administered to 10-day-old calves, 5-month-old calves, and pregnant dams kept under Egyptian environmental conditions. Ninety-five calves and 50 dams were used in the study. All animals were treated with 2 ml/100 kg body weight of killed C cutis. Its effects on body weight gain and on calf mortality and morbidity were recorded. The results obtained showed that treated calves had greater weight gains, reduced susceptibility to common viral pathogens, and lower mortality. When given simultaneously with rinderpest vaccine, an immunopotentiating or adjuvant effect was seen. Thus, treated calves had higher neutralizing antibody titers to rinderpest as compared with untreated calves. When administered to pregnant cows in the last month of pregnancy, the offspring of these animals had higher birth weight, better weight gain, and reduced morbidity.

Adjuvants, Immunologic↗
PubMed1984

Immunoconglutinin and suppression of an induced immune response by plasma from rats infected with Trypanosoma brucei rhodesiense.

Fresh plasma from rats infected with Trypanosoma brucei rhodesiense, incubated with splenic lymphocytes from rats previously immunized with sheep blood cells, suppressed the capacity of the splenic lymphocytes to produce antibody as was indicated by reductions in the numbers of hemolytic Jerne plaques produced by the treated cells. The effect was maximal in plasma samples drawn on the sixth to eighth day of infection when they contained elevated amounts of soluble immune complex, high titers of immunoconglutinin (IK), and reduced titers of lytic complement. We suggest that the active plasma may have affected the antibody-producing cells by one or both of two mechanisms. Soluble antigen-antibody complexes may have interacted with Fc receptors of activated lymphocytes to suppress antibody production. Alternatively, complement-fixing soluble immune complexes may have reacted with C3b receptors of the lymphocytes. These lymphocytes coated with the antigen for IK could then be injured by immunoconglutination.

Animals↗
PubMed1983

Anemia and thrombocytopenia from Corynebacterium parvum-stimulated resistance against malaria, trypanosomiasis, and babesiosis.

Nonspecific immunity (NSI) was manifested in rats injected intravenously with killed Corynebacterium parvum and challenged with Trypanosoma lewisi, Plasmodium chabaudi, or Babesia rodhaini. The NSI became evident some 5 days after infection as a suppressed parasitemia, a more rapid recovery from patent infection and as enhanced survival among rats infected with B. rodhaini. The C. parvum injections produced anemia and thrombocytopenia with splenomegaly and signs of glomerulonephritis in rats. The signs became evident about 5 days after injection and were accompanied by reduced titers of lytic complement, elevated titers of antibody against fibrinogen products (Anti-F), antibody against soluble serum antigen of malaria and babesiosis (ABSA), and antibody against the third component of fixed complement or immunoconglutinin (IK). These were the autoantibodies associated with anemia and reduced parasitemia of infection-induced NSI. In as much as immunoconglutination of blood cells or parasites coated with complement fixing immune complexes was implicated as a functional mechanism in infection-induced NSI, it is possible that these same factors might function in C. parvum induced NSI.

Anemia↗
PubMed1983

Immune complexes and immunoconglutinin interactions associated with altered lymphocyte activity in Plasmodium chabaudi infections.

Fresh plasma from rats infected with Plasmodium chabaudi, incubated with splenic lymphocytes from rats immunized 5 days previously with sheep blood cells, suppressed the capacity of the spleen cells to produce antibody against the sheep cells as was indicated by reductions in the numbers of hemolytic Jerne plaques formed by the treated cells. The effect was maximal in plasma of rats drawn on the 7th day of infection at a time the rats experienced a hemolytic crisis. Serologic studies indicated that the active plasma contained elevated titers of antibody against fibrinogen products, antibody against the soluble serum antigens elaborated during blood infections and antibody against the third component of fixed complement (C3) or immunoconglutinin. Titers of lytic complement were reduced and amounts of soluble immune complex precipitated with polyethylene glycol 6000 were elevated. The active plasma may have affected the antibody producing cells by one or both of two mechanisms. Soluble antigen-antibody complexes could have interacted with Fc receptors of activated lymphocytes to alter their function. Alternatively, the complexes may have fixed complement and interacted with receptors for fixed C3 on the lymphocyte membrane. Such cells, being coated with the antigen for immunoconglutinin, could be altered by immunoconglutination. Inasmuch as the immune complexes in the active plasma were generated in vivo, it would seem unlikely that the plasma would contain significant amounts of complex that had not fixed complement. With immunoconglutinin present in the plasma, alteration of the cells by immunoconglutination seems a more likely possibility.

Animals↗
PubMed1977

The slide agglutination test for the diagnosis of filariasis in camels.

The slide agglutination test was adapted for the diagnosis of filariasis in camels, using an antigen prepared from the microfilariae by a simple lytic technique. The preliminary results were satisfactory as the test detected 86 per cent of the infected animals. Only 6 per cent of the healthy camels with no blood parasites or microfilariae in their blood gave positive results and no positive reactions were obtained from 18 animals suffering from Trypanosoma infection.

Agglutination Tests↗
PubMedDate not supplied

Schistosomiasis as an important determining factor for the response of Egyptian patients with chronic hepatitis C to therapy with recombinant human alpha-2 interferon.

The aim of the present study was to compare the response to recombinant human alpha-2 interferon therapy in 2 groups of Egyptian patients having chronic hepatitis C with or without associated schistosomiasis. Group 1 included 36 patients with associated intestinal schistosomiasis, and group 2 included 24 patients without schistosomiasis. All patients had abnormal serum aminotransferase levels and were negative for hepatitis B surface antigen and anti-hepatitis core antibody, but positive for hepatitis C virus antibody in serum. All patients received interferon at a dose of 3 million units subcutaneously 3 times a week for 6 months and were followed up clinically, biochemically and haematologically during this treatment period and for 6 months thereafter. A second liver biopsy was obtained from every patient after the completion of interferon therapy. Both the percentage of complete response with return to normal of alanine aminotransferase levels during therapy and the overall response rate at 6 months (when patients with a partial response were also included as responders) were significantly lower (P < 0.001) in group 1 (14% and 33% respectively) than in group 2 (63% and 71% respectively). The liver histology also improved significantly in group 2 (46%) compared with group 1 (14%) after completion of therapy (P < 0.05). On the other hand the overall relapse rate in responders, by 6 months after cessation of therapy, was significantly higher (P < 0.05) in group 1 (92%) than in group 2 (59%). These results show that the presence of associated schistosomiasis has to be considered as an important factor in determining the response of Egyptian patients with chronic hepatitis C to therapy with interferon.

Adult↗