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Biomedical subjects

S Mansour

Publications and source records attributed to S Mansour.

At least 55 records · Page 3Linked to original sources
PubMed1992

Limited immunotoxic potential of technical formulation of the herbicide atrazine (AAtrex) in mice.

Immunotoxicity of the technical atrazine formulation, AAtrex, was examined in C57Bl/6 female mice following a sublethal exposure to equivalent 1/2-1.64 LD50 doses of the herbicide. Animal weight was not affected by the herbicide exposure. No dose-related changes could be concluded for fluctuations in organ weight, changes in the spleen cell number and cell viability. Furthermore, cytofluorometric studies showed no significant changes in the frequency of L3T4-positive and Lyt-2-positive T-cells. Functional in vitro assays of mitogen activation showed no marked effects of AAtrex exposure on lymphocyte stimulation by lipopolysaccharide (LPS), phytohemagglutinin (PHA) and concanavalin A (Con-A). In addition, sublethal exposure to AAtrex did not affect interleukin-2 (IL-2) production by splenic cells. Furthermore, no dose-related effect could be concluded from a transient suppression of a primary humoral IgM response to sheep erythrocytes (SRBC) as well as from a transient inhibition of a specific T-cell response to alloantigens in mixed lymphocyte reaction (MLR). Exposure to equiv. 1/2-1/16 LD50 doses augmented phagocytic activity of peritoneal macrophages, without any visible AAtrex dose-related effect. Normal humoral and cellular responses were restored at 14-40 days after the herbicide exposure. Overall, transient and reversible immunosuppression of humoral-mediated and cell-mediated responses and activated macrophage phagocytic activity could not be attributed to the direct chemical-related effect of sublethal exposure to AAtrex.

Animals↗
PubMed1991

Evaluation of the immunomodulatory potential of diethyl dithiocarbamate derivatives.

The cytotoxicity, immunotoxicity and immunomodulatory potential of four dithiocarbamate derivatives were assessed and compared with the effects of Immuthiol (diethyl dithiocarbamate, DE-DTC) in mice. Cellular stimulation and cell viability were examined after in vitro exposure of spleen lymphocytes to selected DTC analogues: N-methyl-D-glucamine dithiocarbamate (NMG-DTC), dimethyl dithiocarbamate (DM-DTC), dibuthyl dithiocarbamate (DB-DTC) and diisobuthyl dithiocarbamate (DIB-DTC). Lymphocyte activation by plant and bacterial mitogens: concanavalin A (Con A), phytohaemagglutinin (PHA), lipopolysaccharide (LPS) and allogeneic stimulation of cells in mixed lymphocyte reaction (MLR) were examined in vitro in the presence of 10(-4)-10(-9) g/ml DE-DTC and other selected DTC derivatives. No direct in vitro lymphoproliferative activity of DTC derivatives was observed, although a relatively stronger cytotoxicity with DE-DTC and DM-DTC was noted. In addition, the in vivo effects of DTC derivatives were examined by cytofluorometric profile of splenic and bone marrow cells as well as in mitogenic and allogenic responses, after i.v. exposures of animals to two subsequent (25 mg/kg b.w.) doses of the chemical. Less cytotoxic DIB-DTC, NMG-DTC and DB-DTC expressed weak in vivo immunostimulatory potential when compared with the effect of DE-DTC, whereas the effects of DM-DTC on alloantigenic and mitogenic lymphocyte stimulation were comparable with the known effects of DE-DTC. Cytofluorometric studies showed that the number of cytotoxic/suppressor T-cells (Ts) and helper T-cells (Th) in the cell was increased by DE-DTC and NMG-DTC only. In addition, DM-DTC appeared to affect the Ts/Th ratio. DE-DTC did not affect the B-cell subpopulation, whereas other derivatives induced marked modifications of the pre-B-cell subpopulations in bone marrow. Our data suggest that in vivo the immunostimulatory effect of DM-DTC could be accompanied with major changes in bone marrow B-cell frequency and alteration of spleen Ts/Th ratio.

Adjuvants, Immunologic↗
PubMed1991

Hepatitis B infection in Sana'a City, Republic of Yemen. Prevalence among pregnant women and materno-foetal transmission.

A cross-sectional study was carried out on 130 pregnant women, chosen randomly from those admitted to the labour ward of Al-Thawra general hospital in Sana'a City, Republic of Yemen. This study was conducted to determine the prevalence of HBsAg among pregnant women and estimate the maternofoetal transmission. The prevalence of HBsAg among studied women was 15.4%, however, 6.9% showed inconclusive positive results. The materno-foetal transmission was documented in 50% of positive HBsAg women. Hepatitis B infection among studied women was usually acquired after 20 years of age. Logistic regression model with stepwise forward selection, demonstrated that maternal age, past history of blood transfusion and abortions were contributing factors for +ve HBsAg maternal status, while parity and past history of abortions were contributing factors in materno-foetal transmission.

Adolescent↗
PubMed1991

Study on the pathogenicity of some Nocardia spp isolated from tap water of Ismailia City, Egypt.

All actinomycetes isolated from canal water, Ismailia water plant and tap water were identified into 5 genera. All Nocardia isolates were identified into 3 species. Two of which, Nocardia transvalensis and Nocardia otitidus-caviarus were recorded in tap water. These species are pathogenic for human kind and animals. The pathogenicity of these isolates was tested on Swiss Albino mice. Symptomatic changes and death of mice inoculated with Nocardia suspension were recorded. The main symptoms were erythema, enduration and inflammation together with abcesses and an increase in the size of the spleen (spleenomegally). It is concluded from these experiments that: i) All Nocardia species isolated from tap water are pathogenic, at least for mice, ii) these isolates could present health hazards to human kind and needs an urgent investigation.

Animals↗
PubMed1990

Lymphokine release as measurement of anti-mouse hepatitis virus type 3 (MHV3) cellular reactions in various mouse lines exhibiting differential susceptibilities to MHV3-induced paralysis.

We found that susceptibility to Murine Hepatitis Virus, type 3 (MHV3)-induced paralysis is controlled by genes of the H-2 complex. In this article, we compared MHV3 antigen specific cellular reactions, in congenic mice harbouring different H-2 genes (or gene). In a first set of experiments, paralysis susceptible (B10.A x A/J)F1, partly susceptible (B10.AQR x A/J)F1 and resistant (B10.Q x A/J)F1 hybrids were infected with live MHV3. Three weeks or more post-infection (p. i.), the spleens and peritoneal exudate (PE) cells from the mice were put into culture. Killed MHV3 was added to cultures, and antigen specific lymphokine production and utilization were measured: IL-1 production by PE cells after 24 hr in culture, IL-2 production by splenocytes after 24 hr in culture, IL-2 utilization (as appraised by splenocyte proliferation) after 96 hr in culture. No clearcut difference, resulting from genetic disparity, could be observed in the antigen-specific responses. In a second set of experiments, mice were primed with ultra-violet radiation killed MHV3. In that case, increases of IL-1 production by PE cells, of IL-2 production by splenocytes and splenocyte proliferation were always observed, compared to PE cells and splenocytes from non-primed (control) donor mice. However, in latter case, addition of MHV3 antigen to cultures did not result in augmentation of antigen specific IL-2 production and utilization. Here again, no genetic effect was observed. We conclude from these results that MHV3 infection elicited strong lymphokine responses, but that antigen-specific IL-1 and IL-2 production did not correlate with the susceptibility to MHV3-induced paralysis.

Animals↗
PubMed1990

Total count of microorganisms contaminating water supply system of Ismailia City, Egypt.

The efficiency of water purification in the French and the British systems of Ismailia city was evaluated concerning the contaminating microorganisms. Counting of microbial contaminants was based on the phenotypic characters of the colony type. Colony-types of eubacteria, eumycetes, Micromonospores and Streptomyces enumerated in the crude water and the different steps of purification. Total counts of microflora in both systems were higher than the counts in canal water. Meanwhile, microbial isolates were higher in the French system than that of the British one. The increased counts in tap water, compared with canal water, were recorded in winter for bacteria and in spring for fungi. These data showed variations in the microbial total counts according to: plant system, steps of purification, chlorination season and type of microbes.

Bacteria↗
PubMed1988

Structural changes in tracheal nerves and muscle associated with in vivo sensitization of guinea pigs.

The ultrastructure of guinea-pig tracheal smooth muscle and its innervation were studied in control and antigen (ovalbumin) sensitized animals. There was a reduction in the frequency and in the proportion of membrane occupied by gap junctions in sensitized muscle. In addition, there was a decrease in the proportion of varicosities with small granular vesicles relative to other nerve varicosities and to the number of smooth muscle cells. Earlier functional studies in vitro (Mansour and Daniel, 1987) did not reveal altered function of adrenergic nerves or adrenoceptors concentration-response curves to a wide variety of agonists and showed few changes. These studies suggest that inflammatory mediators released during antigen-sensitization may regulate the density of gap junctions and influence nerve structure. These studies also suggest that procedures to evaluate directly cell-to-cell coupling and nerve function after sensitization are needed.

Animals↗
PubMed1988

Enhancement of antigen-specific interleukin 2 production by adding liposomes to rabies antigens for priming.

Antigen-specific IL-2 production was assessed, using splenocytes from rabies immune mice incubated for 24 h with rabies virus antigen. The antigenic material used for in vivo priming was either purified glycoprotein from rabies virus, or the inactivated virus. The time between priming, harvesting and restimulation of the splenocytes was 7 days. It was found that when antigenically inert liposomes were injected, together with antigenic material, to the prospective splenocyte donor mice, IL-2 production was enhanced. This augmentation was observed particularly when priming was performed with the inactivated rabies virus.

Animals↗
PubMed1987

Protection from mouse hepatitis virus type 3-induced acute disease by an anti-nucleoprotein monoclonal antibody. Brief report.

Fusion of MHV-3-immune splenocytes from MHV-3-resistant A/J murine strain, with NS myeloma cells produced several hybridomas. Among eight hybridoma clones, the 1E7A4H1 clone secreted kappa IgG2a apparently directed against the nucleoprotein of the MHV-3 virion. The monoclonal antibody was able to neutralize the in vitro cytopathic effect of MHV-3 on cultured L2 cells, and was detected by indirect immunofluorescence on MHV-3-infected cultured YAC cells. In addition, it conferred a significant protection against MHV-3-induced acute disease, if injected intraperitoneally to C57BL/6 mice before inoculation with MHV-3.

Animals↗
PubMed1987

Responsiveness of isolated tracheal smooth muscle from normal and sensitized guinea pigs.

Studies of the responsiveness of strips of tracheal smooth muscle and the changes after sensitization of ovalbumin were carried out. The hypothesis that there might be a generalized or a selective change of airway smooth muscle responsiveness to sensitization was examined in vitro. Agonists acting on muscarinic receptors, alpha 1-, alpha 2-, and beta-adrenoceptors, purine receptors, histamine and serotonin receptors, and leukotriene and prostaglandin receptors were tested, as well as mediators released from local nerves by field stimulation and procedures such as elevation of potassium or addition of Ca2+ ionophores which do not involve specific receptors. Sensitivity to serotonin increased significantly in sensitized animals. Total magnitude of the contraction and subsequent relaxation responses to field stimulation also increased significantly. Neither of these changes was large in magnitude. Although there were a few minor changes in sensitivity (pD2) or in maximum responses, the hypothesis of important changes in responses of any sort in tracheal muscle after sensitization was rejected. The question was raised whether this general absence of changed responsiveness in vitro reflected (i) the failure of sensitization to induce generalized smooth muscle hyperresponsiveness, (ii) the loss of the mechanisms of such responsiveness in vitro, or (iii) the inadequacy of in vitro techniques to assess responsiveness present in vivo.

Adenosine↗
PubMed1986

Maintenance of tone, role of arachidonate metabolites, and effects of sensitization in guinea pig trachea.

A study was made of the mechanisms underlying production of resting active tension in guinea pig tracheal smooth muscle and the changes with active sensitization to ovalbumin. The same types of tissues were also analyzed as to their responses to arachidonate. Responses for each tissue were expressed in relation to a scale between zero active tension and maximum active tension in response to carbachol. A variety of selective and nonselective inhibitors of cyclooxygenase or 5-lipoxygenase were shown to affect active tension in a manner consistent with the conclusion that a cyclooxygenase product, probably prostaglandin F(PGF2 alpha) and not thromboxanes was chiefly responsible. The inhibition of active tension produced by cyclooxygenase inhibition was shown to be related to the initial active tension, such that tissues with greater resting active tension had greater reductions in tone. No differences of major importance were found as to the mechanisms underlying tone production in control and sensitized tissues. The tension changes in response to exogenous arachidonate were also found to be dependent on the initial level of active tension; when this was low, tension increased, when it was high, tension decreased or did not change. Effects of inhibitors on these responses were again consistent with the conclusion that primarily excitant prostaglandins, not thromboxanes, were produced. Some suggestive evidence for production of excitatory and inhibitory nonprostaglandin metabolites was obtained. No difference of major importance between control and sensitized tissues was observed in the magnitude or underlying mechanism of production of active tension.

5,8,11,14-Eicosatetraynoic Acid↗
PubMed1986

Mechanisms of response to antigen in isolated guinea pig trachea after active sensitization.

A study was made of the responses of guinea pig tracheal muscle in vitro after sensitization by either subcutaneous or intraperitoneal administration of antigens. No difference was observed in the responses of strips from either group to cumulative or single doses of antigen. The responses of the tracheal muscle to antigen were analyzed as to magnitude (relative to maximal carbachol responses), time to peak contraction, and time to half decay. Pyrilamine, an H1-receptor antagonist, slowed the onset of contraction and decay. The latter result suggested a role for histamine in controlling the release of or the response to other mediators and the former was consistent with previous evidence that histamine release augments the initial response. An inhibitor of 5'-lipoxygenase and cyclooxygenase (5,8,11,14-eicosatetraynoic acid), indomethacin, and the slow-reacting substance of anaphylaxis (SRS-A) antagonist FPL-55712 all shortened the time to half decay of the contraction, presumably by different mechanisms. The release and actions of leukotrienes may have been limited by eicosatetraynoic acid and FPL55712, respectively, but the action of indomethacin suggests a modulating role for prostanoids in leukotriene action or release. Nordihydroguaiaretic acid both reduced the maximum response and accelerated decay of this response, suggesting that the maximum response depends upon leukotriene release. Cromoglycate, methysergide, and an inhibitor of thromboxane synthetase were without effect. Both tetrodotoxin and atropine delayed the time to peak contraction and tetrodotoxin also delayed the decay of the contraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Effect of phosphonic analogues of glutamic acid on glutamate decarboxylase.

Among the phosphonic analogues of glutamic acid, only 4-amino-4-phosphono butyric acid, the compound which shows the highest affinity for pyridoxal phosphate, inhibits competitively both Escherichia coli and rat brain glutamate decarboxylases. Phosphinothricin, 2-amino-4-(methylphosphino)butyric acid, is a strong inhibitor of the mammalian enzyme.

Animals↗
PubMed1985

Microcephaly, hypergonadotropic hypogonadism, short stature, and minor anomalies: a new syndrome.

Four sibs, three males and one female, had microcephaly, hypergonadotropic hypogonadism, short stature, and multiple congenital anomalies. They had five normal sibs and consanguineous parents. Findings in the affected sibs also included a narrow forehead, synophrys, micrognathia, abnormally folded pinnae, early loss of teeth in three, cubitus valgus in two, genu valgum, gynecomastia, and undescended testes in one. All sibs had normal chromosomes. Results of tests for growth hormone release and adrenocortical function were normal. Luteinizing hormone releasing hormone (LHRH) and human chorionic gonadotropin (hCG) stimulation tests were consistent with primary gonadal failure. Testicular biopsy, performed on two affected males, was normal in one and showed focal atrophy with decreased spermatogenesis in the other. The patients manifest a phenotype different from all other known types of hypergonadotropic hypogonadism and appear to represent a new MCA/MR syndrome.

Adrenocorticotropic Hormone↗
PubMed1983

An evaluation of soft-tissue changes resulting from Le Fort I maxillary surgery.

The soft-tissue profile response to maxillary surgery (impaction and advancement) at the Le Fort I level was evaluated. Data were derived from quality-controlled preoperative and postoperative cephalograms of nongrowing patients with their lips in repose. A standardized tracing technique was used, and this was followed by landmark identification and digitization. Computer measurement of the linear distance of each cephalometric point from horizontal and vertical reference lines was then obtained. Soft-tissue change to hard-tissue change ratios, as well as single and multiple regression equations, were calculated from a patient pool representing fourteen impactions and seven advancements. The results demonstrated many statistically significant correlations. The soft-tissue response to maxillary surgery appeared to be predictable, and the anticipated changes following both impaction and advancement surgical procedures were summarized. Prediction schemes for soft-tissue change evaluation were presented and tested, with a mean error value of approximately 22 percent. In addition, the results of this study led to the following abbreviated conclusions: For the impaction group, (1) the upper lip closely followed the movement of the maxillary central incisor in the horizontal plane, (2) the mandibular soft tissue followed the skeletal mandibular autorotation on an approximately 1:1 basis, (3) the lower border of the upper lip moved superiorly approximately 40 percent of the vertical maxillary change, and (4) there was a superior vertical change in all of the maxillary soft-tissue points. For the advancement group, (1) a progressive increase in the horizontal soft-tissue movement from the tip of the nose to the free end of the upper lip was observed and (2) vertical change in the soft-tissue and horizontal movement of the mandibular soft tissue was unpredictable.

Adolescent↗