PubMed Health⌕ Search

Biomedical subjects

A Soliman

Publications and source records attributed to A Soliman.

At least 37 records · Page 2Linked to original sources
PubMed1992

Studies on the effect of NAD(H) on nitrogenase activity in Rhodospirillum rubrum.

The effect of NAD(P) and analogs of this nucleotide on nitrogenase activity in Rhodospirillum rubrum has been studied. Addition of NAD+ to nitrogen fixing Rsp. rubrum leads to inhibition of nitrogenase. NADP+ has the same effect but NADH or analogs modified in the nicotinamide portion do not cause inhibition. In contrast to ammonium ions, addition of NAD+ leads to inhibition of nitrogenase in cells that have been N-starved under argon. The inhibitory effect of NAD+ is more pronounced at lower light intensities. Addition of NAD+ also leads to inhibition of glutamine synthetase, a phenomenon also occurring when "switch-off" is produced by the addition of effectors such as ammonium ions or glutamine. It is also shown that NAD+ is taken up by Rsp. rubrum cells.

NAD↗
PubMed1991

Low- and high-activity forms of glutamine synthetase from Rhodospirillum rubrum: sensitivity to feed-back effectors and activation of the low-activity form.

Glutamine synthetase from Rhodospirillum rubrum can be isolated in two forms, with low and high activity, respectively, depending on the concentration of combined nitrogen in the medium before harvest. The two forms have been studied with respect to their dependence on Mn2+ and Mg2+ in both the transferase and the biosynthetic assay. There is no difference in pH optimum between the forms in the biosynthetic assay. In addition the pH-optima for the two cations studied are very close, 7.4 (Mg2+) and 7.2 (Mn2+). It also shows that the activity of the low-activity form is higher than that of the high-activity form in the Mn(2+)-dependent biosynthetic assay. The two forms of Rsp. rubrum glutamine synthetase have also been studied with respect to their sensitivity towards feed-back effectors. In the transferase assay both forms are inhibited to essentially the same degree by alanine, glycine, histidine, AMP, CTP and UTP, CTP being the most effective of the nucleotides and of the amino acids alanine causes the highest inhibition. In the biosynthetic assay these effectors show different degrees of inhibition on the two different forms; the high-activity form being the most sensitive. The results are discussed in relation to properties of glutamine synthetase from Escherichia coli and other phototropic bacteria in which regulation of glutamine synthetase is known to be due to adenylylation. It is also shown that the low-activity form of Rsp. rubrum glutamine synthetase can be activated in crude extracts in a reaction that is inhibited by glutamine.

Enzyme Activation↗
PubMed1991

Verrucae treated by levamisole.

To assess the role of levamisole in treatment of different types of warts, a double-blind study was conducted on 40 patients with different types of warts. Patients were divided into two equal groups, A and B. Group A received levamisole 5 mg/kg body weight on 3 consecutive days every 2 weeks for a period up to 5 months, while patients of group B received placebo for the same period. In group A, 12 patients showed complete cure (60%), two showed partial cure (10%), and the remaining six patients showed no response (30%). In group B, complete cure was achieved only in one case. The higher cure rate was observed in plane and common warts, while plantar warts showed no improvement with levamisole treatment.

Administration, Oral↗
PubMed1991

[Ultrasonography in the study of lesions of the menisci and the collateral ligaments of the knee. Findings in 48 surgically treated patients].

The authors report the results of the study of 48/112 patients who underwent US examination of the knee for gonalgia. Meniscopathy or capsular-ligamentous lesions were clinically suspected. US results were compared with arthroscopic or athrotomic findings; the latter two methods were considered as the reference gold standard. US exhibited 81.2% overall diagnostic accuracy, thus confirming its limitations, more evident than those of arthroscopy and arthrography, CT and MR imaging. Major limitations of US were its failed recognition of meniscal tears smaller than 5-6 mm, and its failed distinction of degenerative meniscopathies from common meniscal fractures (with the exception of 2 cases). Moreover, US did not allow cruciate ligament lesions to be demonstrated; however, in all these cases, US did demonstrate increased capsular thickness (greater than 3 mm at the lower margin of femoral condyle). This indirect sign, together with roudness of parameniscus and capsular-ligamentous limitans (at the hemirhyme), and the direct sign of inhomogeneous hyperechogenicity of the meniscal triangle (normally hypoechoic) contributed to raising overall diagnostic accuracy of US to 89.9%. In the 5 patients with a suspected lesion of the medial collateral ligament examined within 48 hours from trauma, US gave 2 false-positive results in 2 cases where forced abduction test was also positive. Massive edema and swelling of adjacent structures prevented the correct evaluation of ligament limitans. In these 2 cases, a lesion in the anterior cruciate ligament was found at surgery; one of them was associated with a meniscal lesion already diagnosed at US. Both parameniscal and popliteal cysts were correctly diagnosed with US. Due to the well-known limitations of clinics in the diagnosis of knee pain, US could be suggested as the examination of choice to evaluate suspected meniscopathy or ligamentous lesions, thanks to its low cost and short execution time. The use of US could also spare the patients more invasive examinations--e.g., arthroscopy and arthrography--and more expensive ones--e.g., CT and MR imaging.

Adolescent↗
PubMed1990

Catecholamines increase lymphocyte beta 2-adrenergic receptors via a beta 2-adrenergic, spleen-dependent process.

We investigated the mechanisms underlying the increase in mononuclear leukocyte (MNL) beta 2-adrenergic receptor (AR) number and responsiveness after acute infusion of catecholamines. Infusion of isoproterenol and epinephrine, but not of norepinephrine, acutely increased MNL beta-AR density, and this was blocked by the beta 2-selective antagonist ICI 118,551 but not by the beta 1-selective antagonist bisoprolol, suggesting a beta 2-AR-mediated effect. Infusion of isoproterenol but not of norepinephrine also induced a lymphocytosis, with an increase in the number of circulating suppressor/cytolytic T (Ts/c)- and natural killer (NK)-cells but a decrease in helper T (Th)-cells, leading to a decreased Th-Ts/c-cell ratio. beta-AR density was higher in Ts/c-cells than in Th-cells. After isoproterenol infusion, beta-AR density was elevated in all lymphocyte subsets but not in monocytes or platelets, suggesting a lymphocyte-specific phenomenon. Infusion of isoproterenol in splenectomized patients did not alter lymphocyte subset composition and only slightly increased beta 2-AR density. In healthy subjects lymphocyte proliferation in response to various mitogens was attenuated after infusion of isoproterenol but not of norepinephrine; this effect was abolished in splenectomized patients. We conclude that the elevated MNL beta-AR density after acute exposure to beta-adrenergic agonists is caused by a release of lymphocyte subsets from the spleen into the circulation and/or by an exchange of lymphocyte subsets between the spleen and the circulation, whereby freshly released splenic lymphocytes appear to carry more beta-AR than those found in the circulation. This appears to impair immune responsiveness in a dual manner, by decreasing the Th-/Ts/c-cell ratio and by rendering lymphocytes more sensitive to the antiproliferative effects of catecholamines via a higher beta-AR density.

Adult↗
PubMed1989

Purification and partial characterization of glutamine synthetase from the photosynthetic bacterium Rhodospirillum rubrum.

Glutamine synthetase (L-glutamate: ammonia ligase (ADP-forming), EC 6.3.1.2) from the photosynthetic bacterium Rhodospirillum rubrum grown under nitrogen fixing conditions has been purified to homogeneity. The purification procedure involves affinity chromatography on ADP-agarose type 2 as the major purification step. The recovery in the purification is 70%. The specific activity of the purified enzyme is about 10-times higher in the gamma-glutamyl transferase assay than in the coupled biosynthetic assay. The molecular weight was determined to 530,000 by native gradient polyacrylamide gel electrophoresis and to 500,000 by gel filtration. The subunits have an apparent molecular weight of 52,000. Glutamine synthetase isolated from Rsp. rubrum which had been exposed to ammonium ions ('switch-off') before harvest had about 20% of the transferase activity compared with the enzyme purified from nitrogen-starved cells. The low-activity form showed two bands on sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

Chromatography, Affinity↗
PubMed1988

Postmenopausal endometrial patterns and serum estradiol concentrations.

Eighty postmenopausal women were subjected to endometrial biopsy. Inadequate biopsy was recorded in 30 cases. In the remaining cases (n = 50) the correlation between endometrial patterns and serum estradiol (E2) was performed. These cases were presenting with uterine bleeding (n = 38) or minor gynecological symptoms (n = 12). Proliferative endometrium was the predominant endometrial pattern whereas endometrial malignancy was only present in 15.8% of the bleeding cases. Serum E2 was significantly elevated in cases having malignant endometrium or adenomatous hyperplasia compared to cases having other endometrial patterns. Serum E2 measurement is recommended as a simple screening test for the detection of postmenopausal endometrial hyperplasia and/or malignancy.

Biopsy↗
PubMed1987

Alpha-ecdysone, a new bracken fern factor responsible for neoplasm induction in the Egyptian toad (Bufo regularis).

Neoplastic lesions were induced in 10 out of 58 experimental toads (Bufo regularis) force-fed with alpha-ecdysone, which naturally occurs in the leaves of bracken fern (Pteris aquilina). The results of this study prove that alpha-ecdysone may be one of the factors responsible for the carcinogenicity of bracken fern plant fed to cattle and other experimental animals.

Animals↗
PubMed1987

Voices in unison: stressful events in the lives of children in six countries.

A 20-event, 7-point scale on the stressfulness of selected unpleasant experiences was administered to 1814 children in Australia, Canada, Egypt, Japan, the Philippines, and the U.S.A. (two groups). Responses indicated that, among these 3rd through 9th graders, there is a remarkable degree of agreement not only in the stress ratings but also in the reported incidences of life events. Granted certain cultural contrasts, the overall findings gave credence to the presence of widespread, common perceptions and attitudes among children. The worlds of the young and of the grown-ups may overlap with each other much less than usually believed.

Child↗
PubMed1978

Experimental scleroma. A histopathological study.

Klebsilla rhinoscleromatis suspension was experimentally inoculated into the nose and maxillary sinus of eight adult healthy rabbits. Two normal litter-mates served as controls. The animals were killed at varying intervals up to five months following the inoculation. Histopathological examination of the upper and lower respiratory tracts revealed a consistent pulmonary peribronchial and perivascular granulomatous reaction with a Mikulic cell-like appearance. The reaction was present in all the inoculated rabbits and increased in severity as the survival period was prolonged. The significance of these findings in the aetiopathogenesis of scleroma and to scleroma in humans is discussed.

Animals↗
PubMedDate not supplied

Effect of combined low dose praziquantel and oxamniquine on different stages of schistosome maturity.

Combined low doses of praziquantel and oxamniquine were tested against different stages of Schistosoma mansoni in infected Swiss albino mice. The effect of combination therapy (1/3 the curative dose of praziquantel plus 1/3 the curative dose of oxamniquine) was compared with the effect of each drug alone, in reduced or full dose. Comparison with infected untreated controls was also made. Drug effects were evaluated on different growth stages of schistosomes by administering the drugs 24 h before infection and 4 h, 1, 2, 3, 4 and 5 weeks after infection. Animals were killed 8 weeks after infection. Worm burden, distribution, tissue egg load and oogram pattern were used in assessing drug efficacy. A potentiating effect was observed in animals receiving combination therapy. The combination regimen was most effective 4 h after infection, producing 96% worm reduction; eggs were not detected in the liver or intestine. Five weeks after infection the same regimen resulted in 98% reduction in the tissue egg load.

Animals↗