Search PubMed⌕ Search

Biomedical subjects

M Sultan

Publications and source records attributed to M Sultan.

At least 19 recordsLinked to original sources
PubMed2002

Spectrophotometric determination of acyclovir in some pharmaceutical formulations.

A simple and reliable spectrophotometric method has been developed for the determination of acyclovir in pharmaceutical formulations. The method is based on its oxidative coupling reaction with 3-methylbenzothiazolin-2-one hydrazone (MBTH) in the presence of FeCl3 as an oxidant to produce deep-green colored species measurable at 616 nm. The absorbance-concentration plot is linear over the range 20-200 microg ml(-1) with minimum detectability of 1.06 microg ml(-1) (4.71 x 10(-6) M). The molar absorptivity was 9.41 x 10(2) l mol(-1) cm(-1) with correlation coefficient (n = 7) of 0.9998. The different experimental parameters affecting the development and stability of the color were studied carefully and optimized. The proposed method was applied successfully to the determination of acyclovir in its dosage forms. The percentage recoveries +/-SD (n = 9) were 98.63 +/- 0.34, 99.61 +/- 0.58, 99.35 +/- 0.58 and 99.72 +/- 0.86 for tablets, ophthalmic ointment and cream, respectively. A proposal of the reaction pathway was presented.

Acyclovir↗
PubMed2002

Binary tree-structured vector quantization approach to clustering and visualizing microarray data.

MOTIVATION: With the increasing number of gene expression databases, the need for more powerful analysis and visualization tools is growing. Many techniques have successfully been applied to unravel latent similarities among genes and/or experiments. Most of the current systems for microarray data analysis use statistical methods, hierarchical clustering, self-organizing maps, support vector machines, or k-means clustering to organize genes or experiments into 'meaningful' groups. Without prior explicit bias almost all of these clustering methods applied to gene expression data not only produce different results, but may also produce clusters with little or no biological relevance. Of these methods, agglomerative hierarchical clustering has been the most widely applied, although many limitations have been identified. RESULTS: Starting with a systematic comparison of the underlying theories behind clustering approaches, we have devised a technique that combines tree-structured vector quantization and partitive k-means clustering (BTSVQ). This hybrid technique has revealed clinically relevant clusters in three large publicly available data sets. In contrast to existing systems, our approach is less sensitive to data preprocessing and data normalization. In addition, the clustering results produced by the technique have strong similarities to those of self-organizing maps (SOMs). We discuss the advantages and the mathematical reasoning behind our approach.

Algorithms↗
PubMed1999

Idiotypic regulation in Schistosomiasis mansoni.

The role of anti-idiotype Ab2 in regulation of the immune response in schistosomiasis was studied. Positive Ab2 could be detected among the newborns of infected mothers and experimentally S. mansoni- infected mice. Negative anti-idiotypic antibodies were observed among children above 3 years and control mice. Increasing levels of anti-idiotypic antibodies were detected among S. mansoni infected children and adults. Higher mean anti-idiotype A2 levels were found among patients with hepatosplenomegaly than those with intestinal manifestations. The kinetics of anti-idiotype Ab2 among the S. mansoni- infected mice started from the end of the first week after infection up to 8 weeks. It was continuous, but with undulating levels. Moreover, the anti-idiotype antibody was able to stimulate lymphocyte proliferation at 8 weeks post infection.

Adult↗
PubMed1996

[Reliability of needle biopsy of solitary thyroid nodules in view of surgical indications].

To evaluate the accuracy of fine-needle biopsy in the management of the solitary thyroid nodules, 320 biopsies without aspiration were performed in 212 patients, iteratively in 91 cases. Among the 212 initial biopsies, 93 smears were found presumably benign (43.9%), 6 malignant (2.8%), 49 benign implying cytologic control (23.1%), 24 suspicious with decision to operate (11.3%), 40 inadequate (18.9%). On 67 surgical indications (malignant or suspicious cytology, or clinical data), 59 operations were performed. The 11 diagnosed cancers (5.2% of the patients; 18.6% of the operations) correspond to six malignant and five suspicious cytologies at the first or second biopsy. On 145 cases without decision to operate, 125 were clinically surveyed, with sometimes another biopsy (mean survey: 27.6 months; range: 6-80 months), and it was never necessary to modify the initial expectancy attitude. Our results, rather similar to those related by most of the previous publications, confirm that the fine-needle biopsy is a reliable and effective means for the etiologic diagnosis of thyroid nodules and the indications for operative intervention. It spares many patients from a useless operation and is worthy to take a leading place in exploring these nodules.

Biopsy, Needle↗
PubMed1996

[Presence of ophthalmopathy in all cases of Basedow disease?].

In order to evaluate the frequency of ophthalmopathy in Graves' disease, we used a progression criterion, the variation of the eyeball protrusion, in a group of 145 patients initially examined at the time when thyrotoxicosis was diagnosed, before any treatment. By the means of a systematic measure of the protrusion with the Hertel's exophthalmometer at every consultation, we calculated for each patient the variation of protrusion (delta PO) between each annual mean value and the initial value. The mean survey was 6.4 years (range 1-18 years). For the whole group, we observed, after a slight increase (0.3 mm) during the first year, a progressive decrease, which reached about 4 mm at the 12th year and kept an afterwards (p < 0.01 at 3 years; p < 0.001 afterwards). The percentage of cases in which the decrease was significant related to the initial value (> or = 2 mm) rose regularly to reach 100% at the 16th year. These results seem to give evidence of the constant nature of ophthalmopathy at the initial stage of Graves' hyperthyroidism.

Eye Diseases↗
PubMed1995

Ultrasonic preparation and obturation of root-end cavities.

This study evaluated the preparation of root-end cavities using an ultrasonically activated file, and the obturation of such cavities. In the first part, the root canals of 40 extracted teeth were prepared to size 40 and irrigated with NaOCl and EDTA. The root ends were resected and the teeth inoculated with Enterococcus faecalis, incubated for 10 days and divided into four groups: control; saline; irrigation; hand instrumentation performed via a retrograde approach up to size 50 using saline irrigant; ultrasonic instrumentation with prebent size 40 K-flex file inserted into a Piezon Master using saline irrigant. The teeth were fixed, sectioned longitudinally and viewed under scanning electron microscopy. Bacterial and smear layer scores were obtained at 1, 3, and 5 mm from the resected end. The bacterial scores for control and saline groups were similar; the scores for each instrumentation group were significantly lower than the control group (P<0.001). In addition, there were significantly fewer bacteria in the ultrasonic group compared with the hand instrument group (P<0.001). The smear layer scores for control and saline groups were similar, and significantly lower than in either instrumentation group (P<0.001). In the second part, root-end cavities were ultrasonically prepared in 20 extracted teeth. Ten cavities were filled with amalgam, and 10 with thermoplasticized gutta-percha and Grossman's sealer. After 24-h storage, the root ends were immersed in dye for 48 h. Cross-sectional slices of the obturated part of the root were evaluated using both light and confocal microscopy for dye leakage along the interface of filling material and dentine. There were no statistical differences between the leakage of amalgam and gutta-percha root-end fillings, nor between the two methods of microscopy.

Dental Alloys↗
PubMed1995

Women's empowerment and reproductive choices.

The authors use data from the 1990-1991 Pakistan Demographic and Health Survey to examine some variables indicating women's empowerment and to analyze the impact of such variables on reproductive choices. They conclude that "most Pakistani women are unaccustomed to the idea of planning children; for them, having children is a phenomenon as simple and common as most other issues of life. Among others who desire a specific number of children, the majority end up having more. It is because socio-cultural influences lead women to have a large family size. Our analysis also denotes similar results, and hence most of the empowerment variables used in this analysis do not explain the variation in the dependent variable as was expected." A comment by Khaleda Manzoor (pp.1,148-50) is included.

Asia↗
PubMed1994

[Late onset hyperandrogenism caused by 3-beta-hydroxysteroid dehydrogenase deficiency].

OBJECTIVES: Clinical manifestations of hyperandrogenism, including hirsutism and acne with or without dysmenorrhoea are well recognized in late onset hyperandrogenism due to deficiency in 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD), yet the frequency of this deficiency in patients with post-puberty hirsutism is not well established. We therefore evaluated retrospectively this deficiency state in women who consulted our unit for manifestations suggestive of hyperandrogenism from 1990 to 1992. METHODS: We included 32 women with clinical manifestations of hyperandrogenism for whom a partial deficit in 3 beta-HSD could be searched for on the basis of hormone assays. Their mean age was 27.5 years (range 14 to 46) and the clinical manifestation was hirsutism in 21 cases, acne in 13, alopecia in 5 and dysmenorrhoea in 11. Diagnostic tests included adrenal stimulation with 0.25 mg beta 1-24 corticotrophin and immunoradioassay of plasma levels of 17-hydroxypregnenolone (17-OHPreg), 17-hydroxyprogesterone (17-OHP), dehydroepiandrosterone (DHA) and cortisol (F). Pang's criteria for the diagnosis of partial deficiency in 3 beta-HSD were retained. We defined deficiency in 3 beta-HSD as certain when the 4 following criteria were present 60 minutes after stimulation: 17-OHPreg > 17.5 ng/ml; DHA > 20 mg/ml; 17-OHPreg/17-OHP > 9; 17-OHPreg/F.10(-3) > 53. Diagnosis was considered probable when only 3 criteria were met and was excluded in all other cases. RESULTS: Positive diagnosis of deficiency in 3 beta-hydroxysteroid dehydrogenase was made in 4 of the 32 patients and probable in 4 others. CONCLUSION: Based on our series of patients, late onset hyperandrogenism due to 3 beta-hydroxysteroid dehydrogenase deficiency would thus appear to be a relative frequent deficiency state. Since therapeutic measures can be taken, this deficiency should be carefully searched for in all young patients presenting with manifestations suggesting hyperandrogenism.

3-Hydroxysteroid Dehydrogenases↗
PubMed1994

Complications of plombage in a Cuban exile.

Collapse of the affected lung, or plombage, was a common operative treatment for tuberculosis in the United States in the 1930s and 40s. Due to the lack of antitubercular drugs, this practice continued in Cuba into the 1950s. After 41 years the plombage material in an exile patient was found to be infected. This resulted in the bronchopleural fistula which required a pectoralis muscle flap to close. Physicians should be aware that many Cuban exiles have been treated for tuberculosis via plombage and are at risk for similar complications.

Bronchial Fistula↗
PubMed1989

The effect of postplacental insertion of the spiked and the standard Lippes loop on uterine involution.

The spiked Lippes loop was inserted in 53 women and the standard loop in 55 women immediately following the delivery of the placenta after normal vaginal delivery. A group of 50 recently delivered women with no IUD was studied as a control. The cases were followed up for 1 year. Ultrasonic scanning was performed during the 6th week after insertion for 47 cases with the spiked loop and 43 cases with the standard loop. All loops were correctly positioned within the uterine cavity except in two cases; one using the spiked and the other using the standard loop. The loops were found displaced downwards and as there was excessive bleeding, the devices were removed. Regarding the effect of the IUD on uterine involution, it was found that the fundus to internal os length for the cases with IUDs was shorter than that among the controls, also this length among the standard loop users was significantly shorter than that of the controls (P less than 0.01). Postplacental IUD insertion did not delay uterine involution, on the contrary, it helped involution. Regarding the effect of lactation, the fundus to internal os length for the fully lactating women either using a loop or not, was found to be significantly shorter than that of the non-lactating cases (P less than 0.002).

Adult↗
PubMed1988

[Improvement of the prognosis of Basedow's disease by using high doses of carbimazole].

The influence of synthetic antithyroid drug dosage on the course of Graves' disease was evaluated by comparing two groups of matched patients treated with carbimazole. Thirty-seven patients received a rapidly degressive treatment (60 mg/day initially rapidly reduced without replacement thyroid hormone therapy), and 36 patients received a prolonged treatment in high doses (60 mg daily for 6 months with progressive reduction of dosage over 5 months and replacement therapy). There was a highly significant difference in the actuarial curves of patients without relapse during 36 months: 82 per cent in patients with high doses, as against 38 per cent in patients with rapidly degressive treatment (log rank: chi 2 = 7.67, P less than 0.01). The anti-TSH receptor antibody titers decreased more rapidly in patients under prolonged treatment with high doses than in those with the rapidly degressive treatment. It is concluded that carbimazole in high doses is more immunosuppressive than in rapidly degressive doses and that it improves the prognosis of Graves' disease.

Adult↗