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Biomedical subjects

M Mansour

Publications and source records attributed to M Mansour.

At least 109 records · Page 6Linked to original sources
PubMed1988

Augmentation of cytotoxic activity by mitogens in rheumatic heart disease.

Natural killer cell activity and alterations in cytotoxicity after culture with streptococcal blastogen A and phytohemagglutinin (PHA) were examined in patients with inactive rheumatic heart disease (RHD) and control patients. Natural cytotoxic activity of mononuclear cells (MNC) did not differ between RHD and control patients with either peripheral blood or tonsils. In cultured blood MNC the level of cytotoxic activity stimulated by blastogen A was significantly greater in patients with RHD at all effector:target cell ratios. These differences in cytotoxic activity were not observed with cultured tonsillar MNC. In similar experiments with a different group of patients, culture with PHA or blastogen A both produced a significantly greater increase in cytotoxic activity in blood MNC from patients with RHD. The increase was significantly lower with PHA than with blastogen A. The ability of mitogens to differentially augment cytotoxic activity in cells from the blood of patients with RHD implies that a population of cells exists in these patients that could be activated during acute rheumatic fever to play a role in pathogenesis.

Adolescent↗
PubMed1987

A substrate amplification system for enzyme-linked immunoassays. Demonstration of its general applicability to ELISA systems for detecting antibodies and immune complexes.

Self recently described a substrate system for alkaline phosphatase (AP)-dependent ELISAs which markedly increased sensitivity, compared to using p-nitrophenyl phosphate. This increase is achieved by having AP, the primary enzyme, produce an activator for a secondary enzyme-substrate system, within which marked amplification occurs. We adapted this technique to study antibodies to casein, bovine serum albumin, ovalbumin, and cardiolipin in the sera of patients with systemic lupus erythematosus (SLE) and normal individuals. The new substrate system yielded titres 30-50-fold higher than those with p-nitrophenyl phosphate (Sigma 104, p-NPP). In addition, when used in a solid-phase C1q binding assay we were able to use a 1 : 100,000 dilution of AP-conjugated anti-human IgG with the amplified substrate, compared to the 1 : 1000 dilution needed with p-NPP. This system is extremely valuable because of its flexibility. It can either be very sparing of limited samples, or if the added sensitivity is not needed, 100-fold less AP conjugate may be used. Thus rare or expensive conjugates can be significantly conserved.

Animals↗
PubMed1987

Compartmentalization of cells bearing "rheumatic" cell surface antigens in peripheral blood and tonsils in rheumatic heart disease.

Monoclonal antibodies that recognize "rheumatic" antigens of peripheral blood non-T cells were used to study the compartmentalization of such cells in peripheral blood and tonsils of individuals with rheumatic heart disease (RHD) and suitable control subjects. The peripheral blood of most (71%) of the 42 individuals with RHD contained cells reacting with monoclonal antibody 83S19.23 or 256S.10, whereas these cells were present in only 17% of the 41 control subjects (P less than .02). However, none of 21 individuals with RHD had such cells in their tonsils, although they were present in the tonsils of 50% of the 40 control subjects (P less than .03). These results may reflect a failure in RHD or organ-specific homing of cells with the epitopes recognized by the antibodies. The presence of these cells in tonsils may be important in the immune response to streptococcal pharyngeal infection, and their absence in RHD may be involved in the unusual immune responses characteristic of this disease.

Adolescent↗
PubMed1987

Lymphocyte subpopulations in rheumatic heart disease.

Monoclonal antibodies and indirect immunofluorescence techniques were used to compare the distribution of lymphocyte subpopulations of tonsil and peripheral blood from patients with rheumatic heart disease and age and socioeconomically matched patients undergoing tonsillectomy for chronic recurrent tonsillitis, but who had no evidence of rheumatic fever or rheumatic heart disease. The proportions of B cells (BA-1+), total T cells (Lyt-3), inducer/helper T cells (T4+) and cytotoxic/suppressor T cells (T8) were determined. No significant differences were apparent between rheumatic heart disease and control groups in resting cells from tonsils or blood. Cells undergoing proliferation in response to streptococcal blastogen A were identified by similar techniques. These tonsillar preparations from patients with rheumatic heart disease generated a smaller proportion of T8+ cultured cells and a greater T4/T8 ratio of cultured cells in response to group A streptococcal blastogen A than did nonrheumatic subjects.

Adenoids↗
PubMed1986

Dynamics of the ureterovesical junction: interaction between diuresis and detrusor instability at the ureterovesical junction in pigs.

In pigs under general anesthesia, the mutual relation between ureterovesical flow and detrusor activity was evaluated with juxtavesical ureteral perfusion pressure measurements and cystometry. At constant bladder filling volume ureterovesical perfusion could provoke detrusor activity, which was positively related to the perfusion rate, and which disappeared after perfusion was stopped. During such involuntary detrusor activity ureterovesical perfusion pressure might increase significantly more than intravesical pressure. It is concluded that ureterovesical flow causes distension of detrusor muscle bundles around the ureteric hiatus, which may trigger local and general detrusor activity in an unstable bladder. During such detrusor activity, due to forces in the bladder wall, resistance to outflow from the upper urinary tract could be significantly more impaired than is reflected by the increase of intravesical pressure at cystometry. The clinical implications are discussed.

Animals↗
PubMed1986

Assessment of the persistence of hexachlorobenzene in the ecosphere.

Various degradation tests were carried out to assess the persistence of hexachlorobenzene (HCB) in the ecosphere. HCB was irradiated with light of various wave-lengths in organic solvents and in water, partly after addition of H2O2 or metal oxides. Photolysis to various dehalogenated products occurred at different rates, depending on concentration and irradiation time; HCB adsorbed on a silica gel was mineralized by light to CO2. A negligible amount of 14C-labelled HCB was mineralized to 14CO2 in various biodegradation tests. In an outdoor lysimeter experiment, 14C residues were found in all parts of wheat plants grown from seeds treated with 14C-HCB. Besides the parent compound and bound residues in plants and soil, very small amounts of soluble polar metabolites were present in the plants; the main product of this group, isolated from roots, was conjugated pentachlorothiophenol. Wheat grown in soil with 14C-HCB residues contained unchanged HCB and bound residues.

Biodegradation, Environmental↗
PubMed1985

Solution of the multiple dosing problem using linear programming.

A system theoretical approach to drug concentration-time data analysis is introduced after the discussion of some relevant concepts as they are used in system theory. The merits of this approach are demonstrated in multiple dosing problem. It is shown that dosage minimization without stringent constraints does not result in the desired therapeutic effect. In a different optimization the discrepancy between the actual and the desired time-histories of the relevant substance's plasma concentration is minimized. It is shown that both of these optimizations can be reduced to linear programming problems which are easily solvable with today's computers. These methods are demonstrated in a case study of dopaminergic substitution in Parkinson's disease where computer simulations show them to yield excellent results. Finally, the limits of this approach are also discussed.

Biometry↗
PubMed1985

Interruption of the inferior vena cava for the prevention of recurrent pulmonary embolism.

Pulmonary embolism in high-risk patients may be minimized by inferior vena caval interruption by ligation, plication, intraluminal filters, or intraluminal balloons. Vena caval filter implantation is the least traumatic of all surgical methods of preventing pulmonary embolism. These nonocclusive methods are preferred to minimize the possible sequelae of venous insufficiency. The prevention of septic emboli requires complete ligation of the inferior vena cava. The transvenous approach to caval interruption by intraluminal filters is particularly useful in severely ill patients. When major surgical procedures are performed for the purpose of caval interruption, the intra-abdominal approach has greater associated mortality and morbidity than does the retroperitoneal approach. The Mobin-Uddin and Kim-Ray Greenfield filters are at present the most frequently used modalities for prevention of fatal pulmonary embolism when intervention is required. In large series of patients where intraluminal caval filters have been utilized, there has been an operative mortality of under 1 per cent, with an incidence of recurrent emboli of under 2 per cent, and an incidence of venous stasis sequelae of approximately 20 per cent. Some clinicians prefer the Greenfield filter over the Mobin-Uddin umbrella because of greater ease and flexibility of placement. In general, however, both transvenous intraluminal filters have been used effectively with acceptable mortality and morbidity, and the device used might properly be determined by the experience of the surgeon.

Anticoagulants↗
PubMed1984

Cell proliferation in carcinoma in bilharzial bladder: influence of pre-operative irradiation and clinical implications.

Cell proliferation in carcinoma in the bilharzial bladder was studied in 92 patients in terms of the in vitro labeling index (LI), cell density (CD) and labeled cell density (LCD) using the in vitro 3H-Tdr technique. Cell proliferation was much greater in high than in low grade tumors and in deep than in superficial parts of the tumor, but was much less dependent on cell type; transitional cell cancer had the highest activity followed by squamous cell and adenocarcinoma. The probability of local recurrence after cystectomy decreased markedly when the LI exceeded 5.0%. The influence of the following three pre-operative radiotherapy regimens was studied: split-course (SC): the initial course consisted of 20 Gy in 10 treatments with a similar course was given after one week, hyper-fractionation using 17 treatments 0.6 Gy each on two successive days, this 2-day course of 20 Gy was repeated after one week, and concentrated irradiation consisting of two treatments, 6.0 Gy each with a gap of one week. Cystectomy was performed 14-20 days after treatment in all groups. Preoperative irradiation was generally associated with an increased probability of local control. The unfavorable influence of a high pretreatment LI was not noted after pre-operative irradiation. The CD was also reduced in proportion to the pretreatment LI. It is proposed that the response to irradiation was proportional to the initial proliferation activity and hence the prognostic significance of tumor grade and pretreatment LI was masked. Postirradiation tumor volume reduction was a strong predictor of treatment outcome. Concentrated irradiation was the least efficient pre-operative irradiation regimen and was associated with the least tumor volume reduction.

Carcinoma↗
PubMed1983

Increased sodium-lithium countertransport in college students with elevated blood pressure.

Blood pressure screening was carried out on a university campus to identify early hypertension or high-normal BP in young adults. Compared with normotensive control subjects of a similar age, drawn from the same population, persons identified as being at the upper end of the BP distribution had significantly increased levels of sodium-lithium countertransport. This difference persisted when other potential confounding variables, eg, overweight, sex, ethnicity, sodium excretion, and age, were taken into account. A positive family history was associated with slightly higher levels of sodium-lithium countertransport, although the effect could be explained by higher present levels of BP. These data suggest that abnormalities of cation transport are present early in the course of the development of hypertension. Measurement of transport levels may provide an estimate of risk of hypertension and allow identification of susceptible persons.

Adult↗
PubMed1980

Non-invasive evaluation of left ventricular function through systolic time intervals following oral administration of SB 7505 in man.

An investigation on the effect of diisobutyric ester of N-methyl-dopamine (SB 7505) on systolic time intervals (STI), heart rate (HR), systolic arterial pressure (SAP), diastolic arterial pressure(DAP), saluretic activity was carried out on 8 male volunteer in-patients who had normal renal, gastrointestinal, cardiac and hepatic functions and were free from other serious illness. SB 7505 was administered orally at three doses of 50, 100 and 150 mg. HR, SAP and DAP either showed no variations or marginal insignificant shifts. STI decreased evidencing a dose-related positive inotropic effect like digitalis, but shorter than digitalis. SB 7505 also showed diuretic action with all three doses investigated. The positive inotropic effect and diuretic activity point to the possible usefulness of SB 7505 in treating some heart and kidney diseases.

Administration, Oral↗