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Biomedical subjects

R Kamel

Publications and source records attributed to R Kamel.

At least 19 recordsLinked to original sources
PubMed2006

Design of a transdermal delivery system for aspirin as an antithrombotic drug.

Aspirin has become the gold standard to which newer antiplatelet drugs are compared for reducing risks of cardiovascular diseases, while keeping low cost. Oral aspirin has a repertoire of gastrointestinal side effects even at low doses and requires high frequent dosing because it undergoes extensive presystemic metabolism. Transdermal delivery offers an alternative route that bypasses the gut and may be more convenient and safer for aspirin delivery especially during long-term use. This study comprised formulation of aspirin in different topical bases. Release studies revealed that hydrocarbon gel allowed highest drug release. In vitro permeation studies revealed high drug permeation from hydrocarbon gel. Several chemical penetration enhancers were monitored for augmenting the permeation from this base. Combination of propylene glycol and alcohol showed maximum enhancing effect and, hence, was selected for biological investigation. The biological performance of the selected formulation was assessed by measuring the inhibition of platelet aggregation relevant to different dosage regimens aiming to minimize both drug dose and frequency of application. The results demonstrated the feasibility of successfully influencing platelet function and revealed that the drug therapeutic efficacy in transdermal delivery system is dose independent. Biological performance was re-assessed after storage and the results revealed stability and persistent therapeutic efficacy.

Administration, Cutaneous↗
PubMed1999

Assessment of splenic functions in patients with hepato-splenic schistosomiasis using non-invasive techniques.

This study was carried out on forty cases, classified into 3 groups; group I: 10 healthy controls subjects, group II: 20 patients with hepatosplenic schistosomiasis and group III: 10 bilharzial patients who underwent total splenectomy. All cases were subjected to clinical examination, abdominal ultrasonography, rectal snips and laboratory investigations which included: stool and urine analysis, complete blood picture, IHAT for bilharziasis, liver function tests, viral markers, estimaton of T-lymphocyte subpopulations (CD(+)3, CD(+)4, & CD(+)8) by flow Cytometry, silver stained blood films to detect argyrophilic inclusions and 99mTc sulphur colloid splenic scan which was applied to group II only. The present results revealed varying degrees of hypersplenism (anaemia, leukopenia & thrombocytopenia) in GII. Seventy percent of this group was positive for HbsAg, HCV or both in association with schistosomiasis. Abnormal red blood cells (acanthocytes, target cells, pitted cells & normoblasts) and inclusion bodies (Howell Jolly bodies, argyrophilic inclusions & pappenhiemer bodies) were detected with different values in GIII. CD(+)4 cells were moderately reduced in GII while they were markedly decreased in GIII. CD(+)8 cells were elevated in GII and returned nearly to the normal values in GIII with decrease in number of total T-lymphocytes. Most patients of GII showed marked squestration of 99mTc labelled R.B.Cs. in the spleen with reversed hepatic/splenic ratio (normally hepatic/splenic ratio is over two). IHAT showed positivity in 90% of patients in GII while it was 50% in GIII. Although total splenectomy improved the haematological pattern and the cytopenias, which are prominent features in hepatosplenic schistosomiasis, yet the immunological profile was still altered. So, it is recommended to perform segmental splenectomy with retention of a normal mass of functioning residual spleen to preserve more immunological function and to protect against life-threatening occurrence of post-splenectomy sepsis.

Adult↗
PubMed1998

Human portal serum stimulates cell proliferation in immature Schistosoma mansoni.

Schistosomula of Schistosoma mansoni were incubated in RPMI 1640 medium containing 10% fetal calf serum, 10% human portal venous or 10% human peripheral venous sera in the presence of bromodeoxyuridine (BrdU) in order to measure differences in cell proliferation. The rates of cell proliferation as expressed by BrdU labelling indices (BLI) were determined as a function of time of incubation by immunohistochemistry using monoclonal antibody to BrdU. Compared to schistosomula cultured in the presence of RPMI plus 10% fetal calf serum, BLIs were increased by 60% in the presence of human portal, but not in peripheral serum. This stimulatory effect was substantially reproduced by a fraction of portal serum with a molecular weight range between 1 and 50 kDa. However, in the presence of human peripheral venous serum, either whole or fractionated, schistosomula showed no significant difference compared to RPMI plus 10% fetal calf serum alone. Furthermore, human portal serum fractions of molecular weight greater than 50 kDa also revealed no significant difference relative to control. The results indicate that portal venous serum component(s) of a molecular weight range higher than most simple nutrients can greatly stimulate the rate of cell proliferation of Schistosoma mansoni schistosomula.

Animals↗
PubMed1990

Endoscopic transnasal surgery in antrochoanal polyp.

The current treatment of antrochoanal polyp is simple avulsion of the nasal part with or without removal of the antral part. The antral part is removed through a Caldwell-Luc antrostomy, inferior meatal antrostomy, or middle meatal antrostomy. In this study, endoscopic surgery was performed in 22 cases of antrochoanal polyps where the antral part was removed through the middle meatus. Two new instruments were designed to help complete removal of the antral part of the polyp through the maxillary ostium. Some points of controversy concerning the antrochoanal polyp are discussed according to the diagnostic and therapeutic endoscopic findings. Endoscopic follow-up of these cases for periods ranging between 6 and 30 months, with an average of 20 months, showed no recurrence. It was concluded that endoscopic surgery of the antrochoanal polyp through the middle meatus could be performed as an outpatient procedure, and is safe and reliable.

Adolescent↗
PubMed1989

Cytokines and immunoglobulin in rheumatic heart disease: production by blood and tonsillar mononuclear cells.

Rheumatic fever and rheumatic heart disease are considered to result from abnormal immune responses after Group A streptococcal pharyngitis. Production of interleukin 1 (IL-1), tumor necrosis factor-alpha (TNF), interleukin 2 (IL-2) and immunoglobulin (Ig) by blood and tonsillar mononuclear cells from rheumatic or healthy children was measured after stimulation in vitro by pokeweed mitogen (PWM) or the streptococcal extracellular product, blastogen A (BLA). Tonsillar cells from patients with rheumatic heart disease produced significantly less IL-1, TNF, IL-2, and Ig than control tonsillar cells. In contrast, blood mononuclear cell cultures from rheumatic children produced more TNF and IL-2 than controls. Our findings suggest that abnormal regulation of cytokine and Ig production may contribute to the pathogenesis of acute rheumatic fever and rheumatic heart disease.

Cells, Cultured↗
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

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↗
PubMed1986

Clinical and immunological results of segmental splenectomy in schistosomiasis.

We evaluated segmental splenectomy in 51 patients who required splenectomy to relieve the symptoms of schistosomal splenomegaly, and compared their course with that of 44 patients who underwent total splenectomy in an unrandomized study. We describe a minor modification of our initial technique. Patients having segmental splenectomy had a similar postoperative course to those having total splenectomy. Conversion of a segmental to a total splenectomy was required in two cases due to technical faults. No regrowth of the spleen has occurred in up to 4 years of observation. We noted an increased percentage of T lymphocytes with an increased ratio of T helper to T suppressor cells in patients having segmental splenectomy. Our cumulative experience supports adoption and wider evaluation of segmental splenectomy in schistosomiasis.

Adolescent↗
PubMed1985

Stimulation of Schistosoma mansoni oviposition in vitro by animal and human portal serum.

UNLABELLED: Coupled adult pairs of Schistosoma mansoni were incubated in medium containing either peripheral or portal serum from rat, rabbit, hamster or humans. Daily egg production was measured. In all cases egg production was significantly increased for pairs in the presence of portal sera compared with that in the presence of peripheral sera. Fractionation of rabbit portal serum according to molecular weight demonstrated that the most active component(s) were in the range of 2,000 to 50,000. These fractions were as effective in stimulating oviposition as whole portal serum. CONCLUSIONS: 1) portal serum factor(s) that stimulate S. mansoni oviposition are present in susceptible and non-susceptible hosts; 2) the molecular weight range for the active components is larger than would be expected for simple carbohydrates, amino acids or free fatty acids absorbed from the gastrointestinal tract.

Adult↗
PubMed1983

Liver collagen-type characterization in human schistosomiasis. A histological, ultrastructural, and immunocytochemical correlation.

Liver biopsies of four patients with hepatosplenic schistosomiasis, two patients with schistosomiasis and chronic active hepatitis, two patients with chronic active hepatitis and four control patients with no clinical evidence of either disease, were examined by standard light microscopic techniques, electron microscopy and immunocytochemical staining for collagen type I, III and B. Pure schistosomiasis showed the classical "clay-pipe stem fibrosis" and granulomata composed of eosinophils, macrophages and lymphocytes. In that group, the hepatocellular damage was less conspicuous than in the groups with chronic hepatitis and was usually confined to the granulomatous or fibrotic areas. Destruction of the normal architecture and infiltration by macrophages and lymphocytes with severe damage of hepatocytes was found only in the cases of chronic active hepatitis, with or without associated schistosomiasis. Increased collagen deposits were demonstrated in all three groups. Types I, III and B were found in the enlarged portal triads and fibrotic septa. The intranodular or intralobular collagen stained negatively for type I and strongly positive for types III and B.

Collagen↗
PubMed1982

Segmental splenectomy in schistosomiasis.

Segmental splenectomy was performed in 5 patients with hepatosplenic schistosomiasis mansoni and symptomatic splenomegaly. The aim was to preserve a functional remnant comprising 20-30 per cent of the bulk of a greatly enlarged spleen. The operative technique involved devascularization of anatomic segments and suture of an omental patch to the residual spleen. This procedure was simple, well tolerated and effective in relieving abdominal discomfort and cytopenias. The residual spleens showed normal uptake of 99Tc-sulphur colloid. If long term observation confirms the value of segmental splenectomy in hepatosplenic schistosomiasis, it may become appropriate therapy for those patients with symptomatic splenomegaly who do not require portal decompression.

Adolescent↗
PubMed1980

Suppression splenic T lymphocytes in human hepatosplenic Schistosomiasis mansoni.

Splenic suppressor cell activity was evaluated in 10 patients with advanced hepatosplenic Schistosomiasis mansoni undergoing elective splenectomy. We used cell mixing experiments to assess the effect of mitomycin-C-treated spleen cells on antigen and mitogen-induced 3H-thymidine incorporation of responder cells. The suppressor to responder ratio was 1.0. Spleen cells from 7 of 10 patients caused at least 20% suppression of phytohemagglutinin-induced 3H-thymidine incorporation of one or more populations of responder cells (spleen cells, autologous and allogeneic peripheral blood mononuclear cells)Responses of peripheral blood mononuclear cells to streptokinase-streptodornase and schistosome soluble egg and worm antigen preparations also were inhibited by co-cultured spleen cells. An inverse correlation was apparent between the spleen cell response to PHA and the suppressor activity of that spleen cell population (r = -0.74, p less than 0.05). Cell purification procedures showed that the active suppressor splenic cell was non-adherent and rosetted neuraminidase-treated sheep erythrocytes. This splenic suppressor T lymphocyte may modulate splenic and peripheral blood lymphocyte responses in patients with hepatosplenic schistosomiasis.

Adolescent↗
PubMed1980

A fully automated, continuous-flow radioimmunoassay for methotrexate.

We describe a fully automated continuous-flow radioimmunoassay for methotrexate. [125I]Histamine-labeled methotrexate was used as tracer. Anti-methotrexate serum was coupled to a magnetizable solid-phase and the bound and free fractions were separated with an electromagnetic field. The assay is precise (CV less than 2.5%) and rapid (30 samples per hour), incubation volume is small (about 160 micro L), and incubation brief (10 min). The accurate timing inherent in the system obviates the need to attain equilibrium, so that assay of each sample takes only 15 min. The assay is sensitive (1--100 microgram/L). There is no significant carryover between samples of high and low concentration. Results by the automated method correlated well with those by both a manual assay in which the same reagents and separation technique are used (r - 0.99) and a competitive protein-binding assay (r = 0.96).

Autoanalysis↗
PubMed1979

Concurrent responses of peripheral blood and splenic mononuclear cells to antigenic and mitogenic stimulation in human hepatosplenic schistosomiasis.

Lymphocyte reactivity and its control was assessed in human hepatosplenic schistosomiasis, a disease in which host hypersensitivity may contribute to long-term morbidity. Antigen- and mitogen-induced incorporation of [3H]thymidine was evaluated in peripheral blood and splenic mononuclear cells of 15 patients at the time of splenectomy. The response to phytohemagglutinin (PHA) was depressed in the peripheral blood of 42% and in the spleen cells of 70% of these patients. Significant stimulation was noted, however, upon culture of blood with soluble schistosome egg antigen (SEA) in 80% and of spleen cells in 100% of the patients whose respective responses to PHA were depressed. The contribution of adherent cells to the overall response of mononuclear cells was evaluated by depletion techniques. A significant and specific decrease in the response of the resulting thymus-derived (T) lymphocyte-enriched splenic mononuclear cells to SEA was noted. These studies suggest preferential preservation of the response of circulating and splenic lymphocytes to SEA despite impairment of PHA reactivity in human hepatosplenic schistosomiasis, which may be causally related to the advanced disease of this group of patients. Moreover, activity of helper adherent cells was consistently restricted to the splenic T-lymphocyte response induced by the specific antigen SEA.

Adolescent↗