Biomedical subjects

F Mahmoud

Publications and source records attributed to F Mahmoud.

13 recordsLinked to original sources

PubMed2001

A versatile functional-anatomic image fusion method for volume data sets.

We describe and validate a volumetric three-dimensional registration method, and compare it to our previously validated two-dimensional/three-dimensional method. CT/MRI and SPECT data from 14 patients were interactively fused using a polynomial warping technique. Registration accuracy was confirmed visually and by a nonsignificant F value from multivariate analysis of the transformed landmarks, a significant difference of the squared sum of intensity differences between the transformed/untransformed and the reference volume both at the 0.05 (p > 0.05) confidence level and an average 31% improvement of the correlation coefficient and cross correlation. For the two-dimensional/three-dimensional method, ROI center-to-center distance ranged from 1.42 to 11.32 mm (for liver) with an average of 6.13 mm +/- 3.09 mm. The average ROI overlap was 92.51% with a 95% confidence interval of 90.20-96.88%. The new method is superior because it operates on the true three-dimensional volume. Both methods give good registration results, take 10 to 30 min, and require anatomic knowledge.

Humans↗

PubMed2001

Lymphocyte subpopulation frequency and presence of anti-cardiolipin and anti-nuclear antibodies in peripheral blood of Kuwaiti women experiencing recurrent pregnancy loss.

Recurrent pregnancy loss (RPL) is often associated with elevated levels of serum antiphospholipid antibodies, which contribute to the pathology of the disorder by promoting formation of thromboses, leading to placental infarction and fetal loss. Patients with recurrent pregnancy loss also exhibit pathological alterations in composition and activity of peripheral blood lymphocytes, which may be indicative of an autoimmune processes. This investigation examines the correlation between levels of anticardiolipin antibody (AC) and specific subsets of the lymphocyte repertoire in RPL patients, with the objective of further characterising the immunological basis for RPL. Non-pregnant Kuwaiti women with a history of RPL were subdivided into two cohorts based on presence or absence of elevated plasma antibodies to cardiolipin. Whole blood from these individuals was analysed by flow cytometry for selected lymphocyte subsets and compared with a non-RPL control population. When compared with controls and low AC titre subjects, women with a high AC titre exhibited significantly elevated percentages of pathogenic CD5+ B cells; two categories of activated T cells including CD4+CD25+ and CD8+CD25; NK cells and CD3+NK cells; naive (CD4+CD45RA+) cells; and transitional (CD45RO+CD45RA+) cells. In conclusion, women with elevated levels of AC antibodies possess substantially higher levels of activated T cells and pathogenic B cells, suggesting a fundamental predisposition to immune-mediated rejection of the fetus by these patients. Further characterisation of this phenomenon may allow development of novel intervention methods for management of RPL.

Journal Article↗

PubMed2001

Pregnancy-associated changes in peripheral blood lymphocyte subpopulations in normal Kuwaiti women.

It has recently been reported that healthy pregnancy is associated with systemic immunosuppression. The aim of this study was to evaluate the numbers and distribution of lymphocyte subpopulations in normal, healthy pregnant Kuwaiti women. Thirty-four healthy normotensive women in the 3rd trimester of pregnancy were studied using flow cytometry to define lymphocyte subpopulations and were compared with 16 non-pregnant women. A decrease in the absolute numbers of lymphocytes was observed affecting T cells (CD3+, CD4+, CD8+), B cells (CD19+), and natural killer cells (CD16+/CD56+). When analyzed as a percentage of the total lymphocyte population, there was a significant decrease in B cells and an increase in CD4+ T cells. The T cell population revealed increased expression of CD25 on CD4+ and CD8+ cells, of HLA-DR on CD8+ cells, and of CD54 on CD4+ T cells. The reduced number of lymphocytes suggests that Kuwaiti females may be immunosuppressed in the 3rd trimester of pregnancy. The presence of activated CD4+ T cells could indicate the expression of a regulatory suppressor T cell population, as Treg cells are CD4+CD25+, and suppressor T cells are thought to be CD8+. Future work is required to explore the significance of these T cell populations in pregnancy.

Adult↗

PubMed2000

In vitro effects of Ginkgolide B on lymphocyte activation in atopic asthma: comparison with cyclosporin A.

The effects of Ginkgolide B (BN52021) on in vitro activation responses of human peripheral blood mononuclear cells (PBMC) from asthmatic patients was measured using 2-channel flow cytometric analysis of activation-associated cell surface antigens or ELISA assays for cytokines known to be expressed by PBMC during T1 or T2 immunological activation. BN52021 is an anti-inflammatory extract of Ginkgo biloba and has been used therapeutically. It is a known inhibitor of platelet activating factor (PAF), which is important in the pathogenesis of asthma, and may synergise with cyclosporin A (CyA) to inhibit pathogenic immune activation in asthmatics. We compared the inhibitory effects of BN52021 and CyA (1 microM each) on activation of PBMC of asthmatic patients stimulated by phorbol myristate acetate and calcium ionophore. Inhibition of production of the cytokines IL-4 and IL-5 by BN52021 was insignificant compared to CyA. However, BN52021 significantly reversed the increase in activation-associated CD45RA expression, with a trend towards decreased expression of HLA-DR. Lymphocyte activation markers were not significantly altered by CyA. Since they appear to have differing effects on activated cells, the anti-inflammatory effects of CyA and BN52021 in atopic asthma is potentially additive. The present approach may be useful for preliminary evaluation of novel therapeutic modalities for asthma treatment.

Adult↗

PubMed1999

Elevated B-lymphocyte levels in lesional tissue of non-arthritic psoriasis.

Psoriasis is a chronic inflammatory skin disorder characterized clinically by maculopapular skin lesions and on the cellular level by increased T-lymphocyte activation in the peripheral blood and migration of activated T-lymphocyte into the lesions. The lymphocyte subpopulations in peripheral blood from 21 Kuwaiti patients showed elevated levels of the T-lymphocyte activation marker CD25, as well as increased expression of HLA-DR compared with a group of age and sex-matched controls, confirming published findings on psoriasis. In addition, there was a tendency towards a significant increase in the CD4+/CD45RO+ (memory cell) population that was also consistent with peripheral T-lymphocyte activation. Immunohistological studies showed a heavy infiltrate of all cell types into the lesional tissue including, as expected, activated T-lymphocytes. An unexpected finding was significantly higher levels of B-lymphocytes infiltrating the psoriatic lesions; they numerically exceeded the T-lymphocyte infiltrate. This has previously been reported only in cases of psoriasis with concurrent arthritis. None of the subjects had arthritis, suggesting an immunopathological variant of psoriasis possibly specific to this population group.

Adult↗

PubMed1999

Differential expression of interferon gamma by mitogen-stimulated peripheral blood mononuclear cells among Kuwaiti psoriasis patients.

Most diseases exhibit characteristic profiles of cytokine expression, broadly subdivided into Th1, involving primarily cell-mediated responses, of which Interferon-gamma (INF-gamma), Interleukin-2 (IL-2) and Tumor Necrosis Factor-alpha (TNF-alpha) are hallmarks, and Th2 processes, which often involve activation of the humoral arm of the immune system, resulting in elevated levels of IL-4, IL-5 and IL-10. Psoriasis, a disorder characterized by disfiguring skin lesions and elevated levels of activated CD4+ T helper lymphocytes in both peripheral blood and lesional tissue, exhibits a profile of cytokine expression that includes high levels of TNF-alpha and IFN-gamma, with low IL-5 and IL-10, indicating that immunologically, the pathogenesis of the disease is Th1. In this study, we report the results of an investigation of peripheral blood mononuclear cell cytokine expression among Kuwaiti psoriasis patients; we demonstrated two patterns of IFN-gamma production which may suggest differing pathogeneses. Whole, haparinized blood was donated by 17 patients with active psoriasis and 11 healthy control subject. Mononuclear cells were isolated by density centrifugation and cultured for 3 days in the presence or absence of a mitogen (PHA). Supernatants were assayed for IFN-gamma (a Th1 marker) and IL-10 (a Th2 marker) by enzyme-linked immunoabsorption assay (ELISA). IFN-gamma expression by both PHA-stimulated and unstimulated cultures from psoriatics significantly exceeded that of controls (p < 0.001), whereas no significant differences in IL-10 expression were noted between psoriatic and control subjects. Stimulation indices (cytokine concentration in PHA-stimulated/unstimulated cultures, SI) for psoriatic subjects were significantly higher than those of controls for IFN-gamma (p = 0.000), but not for IL-10. Ratios of SI (SI IFN-gamma/SL IL-10) for the psoriatic subjects also were significantly greater for the psoriatic subjects than for the controls (p = 0.003). However, within the psoriatic group, eight patients failed to show the expected elevation of IFN-gamma/IL-10 ratio as a result of high unstimulated levels of IFN-gamma production. The divergence of IFN-gamma expression within the psoriatic group may indicate two different modes of T lymphocyte activation contributing to the pathogenesis of psoriasis in this study.

Adult↗

PubMed1998

Peripheral T-cell activation in non-segmental vitiligo.

Vitiligo is a hypopigmentary dermatosis of probable autoimmune origin. Previously reported aberrations in peripheral blood mononuclear cells (PBMC), especially T cells and T cell subsets, have been inconsistent. Lymphocyte subpopulations were examined using flow cytometry and monoclonal antibodies against CD4, CD8, CD20, CD25, CD45RA, and HLA-DR in 34 patients with non-segmental vitiligo. Twelve patients had not received any previous treatment and 22 had previously received at least one course of PUVA therapy that was discontinued at least four months prior to our study. Compared to matched controls, we found significant increases in CD25 and HLA-DR in vitiligo patients (p = 0.000). An inverse correlation was observed between HLA-DR and patient status with regard to treatment (p = 0.001). These results suggest a role for T cells in the pathogenesis of vitiligo and imply that previous PUVA therapy may be reflected by an alteration in circulating DR +ve cells.

Adult↗

PubMed1993

Short and medium term outcomes after rollerball endometrial ablation for menorrhagia.

OBJECTIVE: To review prospectively the intraoperative, short and medium term outcomes of patients treated by rollerball endometrial ablation during the learning curve for this relatively new procedure. PATIENTS AND TECHNIQUES: Seventy-seven women with menorrhagia (71 with dysfunctional bleeding; six with additional small intramural myomas) underwent hysteroscopic rollerball endometrial ablation by coagulation diathermy during 1.5% glycine irrigation, after a two-month period of hormonal suppression. OPERATIVE AND SHORT-TERM EFFECTS: These were recorded at operation and six-week follow-up. No serious short-term complications were recorded. Objective measurement of intraoperative blood loss was always less than 20 mL. One woman experienced uterine perforation with a narrow cervical dilator which did not interfere with the ablation, and two patients had mild postoperative uterine infections. One patient experienced persistent postoperative pain. MEDIUM-TERM OUTCOME: This was recorded at each visit, or by telephone, and confirmed by questionnaire at one year. Twenty-five per cent achieved complete amenorrhoea, 29% staining only, 30% light periods, 10% "normal" or erratic periods and 6% were unchanged. Five patients underwent a second ablation, and three of these later underwent hysterectomy. Measured menstrual blood loss fell from 104 +/- 19 mL (mean +/- standard error of mean) to 1.7 +/- 1.1 mL at six months in 18 women. Other menstrual symptoms were also often dramatically reduced. Of those women with dysmenorrhoea, 33% were cured and 43% markedly improved; of those with midcycle pain, 28% were cured and 53% markedly improved; of those with significant premenstrual symptoms, 13% were cured, 47% markedly improved, 11% unchanged, and 6% were worse. CONCLUSIONS: This new procedure is a safe and effective treatment for menorrhagia caused by dysfunctional uterine bleeding, with impressive ancillary benefits for dysmenorrhoea, midcycle pain and premenstrual tension. It is often called minimally invasive surgery, but it must be recognised that it is not minor surgery.

Adult↗

PubMed1977

Kinetics of early insulin response by the isolated and perfused rat pancreas. Suggestion for two different actions of glucose on the insulin releasing process.

The permissive action of glucose (or glyceraldelhyde) is necessary to the glucagon induced insulin release. By collecting every 15 seconds the venous effluent of the perfused and isolated rat pancreas it was observed that the insulin response to glucagon (2 microgram/ml) was immediate if the pancreas was preperfused with low concentration of glucose (5 mM) or glyceraldelhyde (2,5 mM). On the other hand glucagon alone elicited no response, and the insulin discharge occurred 60 to 90 seconds after the addition of glucose (5 mM) or glyceraldelhyde (2,5 mM) this time being probably allowed to the metabolism of the sugar. The pancreatic response to 15 mM glucose occurred also 60 to 90 seconds after the stimulus. On the other hand when the medium contained a low concentration of glucose (or glyceraldelhyde) increasing the glucose concentration by 10 mM provoked an immediate insulin release. This suggests that glucose has two actions differing by their lag phase. One, "permissive", apparent after some delay, mimicked by glyceraldelhyde, necessary for glucagon induced insulin release, is mediated probably by the metabolic products of the sugar. The second, "triggering", initiates instantaneously the insulin release but appears dependent on the first action.

Animals↗

PubMed1977

Value of serum copper measurement in acute leukaemia of childhood.

Serum copper level (SCL) determination was carried out on sixteen normal children and on 16 with acute leukaemia. A significant increase in SCL was observed in cases of leukaemia than in normal controls. Drop of SCL occurs in cases who respond to quadruple chemotherapy, while those who failed to respond showed persistantly high serum copper level.

Acute Disease↗

PubMed1977

Birth weight in relation to maternal socio-economic status.

On an attempt to illustrate the influence of maternal socio-economic status on birth weight, this study was carried out on 689 full term new borns. The weight, age, parity, income and occupation of their mothers were compared to the birth weight. A correlation was also performed between birth weight and the presentation of the babies and the ante-natal care offered to their mothers. A positive correlation was only found to be present between birth weight and family income below 10 pounds/month. A similar correlation was noticed between birth weight and the interpregnancy interval up to 30 months. The presentation of the foetus might be of influence on birth weight only in cephalic and breeck presentation. The age of the mother, occupation, weight were negatively correlated with birth weight.

Birth Weight↗

PubMed1975

Kinetics of the early insulin response of the perfused rat pancreas to various metabolites and tolbutamide.

The collection every 15 seconds of the portal effluent of the isolated and perfused rat pancreas permitted the following observations: while the insulin response to tolbutamide (250 or 125 mug/ml) occurred immediately, that to glucose (15 mM), or to 1-leucine (15 mM) was delayed by 60-90 seconds. The response to d-glyceraldehyde occurred slightly but significantly more quickly than that of glucose. The response to alpha-keto-isocaproate was an intense and immediate one. Isovalerate elicited no insulin discharge. These results suggest that d-glucose and l-leucine have to be metabolized to stimulate insulin secretion and that alpha-keto-isocaproate seems to be a direct and specific signal.

Animals↗

PubMed1972

Herpes gestationis.

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Dermatitis Herpetiformis↗