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Biomedical subjects

S Ahmed

Publications and source records attributed to S Ahmed.

At least 181 records · Page 10Linked to original sources
PubMed2000

Thoraco-lumbar duplication of the spine. Case report and embryology review.

OBJECT: We present a case of an asymptomatic and neurologically normal 6-year-old girl who was noted to have a gross spinal abnormality. METHODS: Neuroimaging demonstrates gross thoraco-lumbar spine duplication, which is at the severe end of the split cord malformation (SCM) group of congenital abnormalities. Despite the position of the neural structures, the clinical condition has so far not suggested that any surgical intervention is indicated, though the girl's later growth spurts may still unmask features of a tethered spinal cord. CONCLUSIONS: We present a brief review of the literature dealing with theories of embryogenesis relating to SCM, the common clinical and radiological features, and finally the surgical options available.

Child↗
PubMed2000

Construction of a neourethra in girls: follow-up results.

Female urethral injuries may cause serious morbidity with loss of the entire urethra in some cases. We review the results of construction of a neourethra by the flipped anterior bladder-tube technique in five girls aged 3-18 years (mean 8 years). All had pelvic fractures and had their initial management elsewhere; four were run over by motor vehicles and one suffered a pelvic gunshot injury. Three patients came with a suprapubic cystostomy, one was totally incontinent, and another had a urethrovaginal fistula. Three had an associated vaginal injury. All five patients underwent construction of a neourethra using a flipped anterior bladder-wall tube (FABWT) and have been followed for 18-80 months (mean 44 months). All patients were continent in the daytime and three passed urine spontaneously. Two were managed by clean intermittent catheterization (CIC), one per urethram and other via a continent abdominal stoma (Mitrofanoff). The FABWT technique should be considered as an option in the management of females with severe urethral injury.

Adolescent↗
PubMed2000

Fanconi's anemia with solitary crossed renal ectopia, vesicoureteric reflux, and genital abnormalities.

Fanconi's anemia is an autosomal recessive disease, the main feature being pancytopenia secondary to bone-marrow hypoplasia. However, multiple congenital abnormalities may be encountered, urogenital malformations being common. We describe a patient with solitary crossed renal ectopia, vesicoureteric reflux, hypospadias, and unilateral undescended testis with absent vas deferens.

Child, Preschool↗
PubMed2000

Bladder-wall abscess in a girl with neurogenic bladder.

We report a case of a bladder-wall abscess in a patient with myelodysplasia and a neurogenic bladder. The aetiology of the abscess was obscure, but the patient had recurrent urinary tract infections and was being managed by clean intermittent catheterisation.

Abscess↗
PubMed2000

Lumpectomy margins, reexcision, and local recurrence of breast cancer.

BACKGROUND: The diagnosis of breast cancer is often made by excisional biopsy without margin assessment for mammographic findings or palpable masses. Many patients treated with breast conservation undergo reexcision to obtain clear margins although the relationship between clear margins and local recurrence remains controversial. METHODS: Patients undergoing breast conservation and adjuvant radiation therapy with complete follow-up over 5 years were studied. Factors associated with obtaining clear histopathologic margins and undergoing reexcision to obtain clear margins were studied in relation to the risk of local recurrence. RESULTS: Clear biopsy margins were associated with diagnosis by fine-needle aspiration cytology (fine-needle aspiration 42%, spot localization 11%, excisional biopsy 10%; P <0.001). Reexcision was significantly related to diagnostic method (spot localization 63%, excisional biopsy 36%, fine-needle aspiration 10%; P <0.001), first margin status (clear 0%, close 11%, positive 46%, unknown 48%; P <0.001), patient age (54 years for reexcised patients and 58 for non-reexcised patients; P <0.001), and tumor size (mean tumor size 1. 4 cm for reexcised patients and 1.7 cm for non-reexcised patients; P = 0.003). Patients undergoing reexcision were significantly more likely to be diagnosed by spot localization, have nonnegative excisional biopsy margins, be younger, and have smaller tumors than patients not undergoing reexcision. Local recurrence was not significantly related to margin status (8% with clear margins, 7% with positive margins, 19% with close margins, and 11% with unknown margins) or reexcision (10% local recurrence rate for patients with negative final margins after reexcision and 12% with positive, close or unknown first margin without reexcision). Estrogen receptor status was the only variable related to local recurrence in Cox proportional hazards model (P = 0.009). Estrogen receptor negative patients with nonnegative margins experienced a 20% rate of local recurrence compared with 10% for estrogen receptor negative patients with negative margins and 7% for estrogen receptor positive patients regardless of margin status (P = 0.021). CONCLUSIONS: Clear excision margins are facilitated by preoperative diagnosis by fine-needle cytology. For patients with nonnegative margins, reexcision was more commonly performed in young patients with small tumors diagnosed by spot localization biopsy. The relationship of local recurrence to margins and reexcision was not statistically significant. Estrogen receptor negative tumors with nonnegative margins had a significantly higher rate of local recurrence than estrogen receptor negative tumors with clear margins and estrogen receptor positive tumors regardless of margin status.

Adult↗
PubMed2000

Effects of lisinopril and amlodipine on antioxidant status in experimental hypertension.

The objective of this investigation was to compare changes in antioxidant status (together with other metabolites relevant to hypertension) in plasma and cardiac tissue from spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY), following 8 weeks of treatment with lisinopril (angiotensin converting enzyme inhibitor) or amlodipine (Ca(2+) channel antagonist) respectively. There was no significant difference in the levels of total antioxidant capacity, retinol, urea, albumin or triglyceride in plasma from SHR or WKY rats, with or without lisinopril or amlodipine treatment. However in SHR rats, levels of alpha-tocopherol were substantially reduced in both plasma (-54% WKY, P<0.01) and cardiac tissue (-43% WKY, P<0.05). Treatment with lisinopril ameliorated reduced levels of plasma alpha-tocopherol in SHR rats, but not in cardiac tissue. Amlodipine treatment had no effect on alpha-tocopherol levels in plasma or cardiac tissue in SHR rats. In SHR rats total cholesterol levels were significantly lower thanWKY controls (-36%, P<0.001). This effect was reversed in lisinopril treated SHR rats (+27%, P<0.01). Plasma high density lipoprotein (HDL) and low density lipoprotein (LDL) cholesterol were reduced in untreated SHR rats (P<0.025) when compared to WKY controls; neither lisinopril nor amlodipine treatment significantly altered these parameters. These findings suggest possible alternative mechanisms of action for lisinopril, and reinforce its use in hypertensive patients or patients with left ventricular hypertrophy.

Amlodipine↗
PubMed2000

Spectrofluorimetric analysis of certain 4-quinolone in pharmaceuticals and biological fluids.

A highly sensitive spectrofluorimetric procedure is developed for the analysis of certain 4-quinolone antibiotics: sparfloxacin (I), oxolonic acid (II), flumequine (III) and enrofloxacin (IV) in their pharmaceutical dosage forms or in biological fluids. This procedure is based upon the intrinsic fluorescence in acetonitrile for sparfloxacin or upon the highly enhanced fluorescence obtained by the interaction of the drugs with AlCl3. The optimum pH for the maximum fluorescence intensity is 8-8.5 for I, 5-6 for II, III and pH 3.5 for IV. The different experimental parameters that affect the fluorescence intensity were carefully studied and incorporated into the procedure.

Calibration↗
PubMed2000

Evaluation of the efficacy of Lawsonia alba in the alleviation of carbon tetrachloride-induced oxidative stress.

The hepatoprotective activity of the 50% ethanol extract of the bark of Lawsonia alba syn. L. inermis was investigated against the carbon tetrachloride-induced oxidative stress. Pretreatment of rats with doses of 250 and 500 mg/kg of the plant extract significantly (P < 0.001) lowered serum transaminases (GOT and GPT) and LDH levels, respectively, in a dose dependent manner against the significant (P < 0.001) rise of these damage marker enzymes when challenged with CCl4 (1 ml/kg, orally). Parallel to these changes, the plant extract prevented CCl4-induced oxidative stress by significantly maintaining the levels of reduced glutathione (GSH), its metabolizing enzymes and simultaneously inhibiting the production of free radicals. Pretreatment of rats with the extract also inhibited the peroxidation of microsomal lipids in a dose-dependent manner.

Animals↗
PubMed2000

New contraceptive methods.

As the number of abortion procedures performed each year reaches nearly 1 million, the incentive to decrease the incidence of unwanted pregnancy in the United States is high. Better education regarding women's health issues and enhanced contraceptive development are necessary to impact this long-standing problem. Several new contraceptive products are likely to become available in years to come to increase the number of choices that women and their health care providers have for pregnancy prevention. These products include long-acting implants, the levonorgestrel intrauterine device, patches, and the vaginal ring. This article surveys the near future of male and female contraception.

Administration, Cutaneous↗
PubMed2000

Comparative assessment of chemical and gamma-irradiation procedures for implantable glucose enzyme electrodes.

Chemical and gamma-irradiation sterilisation were examined in this study for implantable needle electrodes. Exposure to isopropyl alcohol (IPA) led to response elevation, but time-dependent exposures up to 30 min variously to chlorhexidine, H2O2, HCl, HCl/IPA, and alcoholic iodine/potassium iodide, all caused substantial time-dependent response degradation. Sterility was not assessed for such electrodes. High dose (30 KGy) gamma-irradiation also compromised sensor response, with exposed electrodes exhibiting approximately 30% reduction in response, comparable in magnitude to 10 min exposure to chemical sterilisation. However, a lower dose (25 KGy) gamma-irradiation was well tolerated and subsequent microbiological testing (following contamination with Streptococcus epidermidis and Staphylococus aureus) proved device sterility with no culture growth following 7 days incubation at 37 degrees C in brain heart infusion medium.

2-Propanol↗
PubMed2000

A conserved checkpoint pathway mediates DNA damage--induced apoptosis and cell cycle arrest in C. elegans.

To maintain genomic stability following DNA damage, multicellular organisms activate checkpoints that induce cell cycle arrest or apoptosis. Here we show that genotoxic stress blocks cell proliferation and induces apoptosis of germ cells in the nematode C. elegans. Accumulation of recombination intermediates similarly leads to the demise of affected cells. Checkpoint-induced apoptosis is mediated by the core apoptotic machinery (CED-9/CED-4/CED-3) but is genetically distinct from somatic cell death and physiological germ cell death. Mutations in three genes--mrt-2, which encodes the C. elegans homolog of the S. pombe rad1 checkpoint gene, rad-5, and him-7-block both DNA damage-induced apoptosis and cell proliferation arrest. Our results implicate rad1 homologs in DNA damage-induced apoptosis in animals.

Animals↗
PubMed2000

A genome-based study of consanguinity in three co-resident endogamous Pakistan communities.

In a study based on 173 individuals drawn from three endogamous, co-resident communities in the province of Punjab, the Awan, Khattar and Rajpoot, an analysis of 10 autosomal single tandem repeats on chromosomes 13 and 15 revealed distinctive genetic profiles in each community. A total of 99 different alleles were detected, with 28 alleles (28.3%) shared by all three communities. The mean private allele frequency was 7.7%. There was a reduction in heterozygosity and high average inbreeding effects (FIS and/or HS), particularly in the Awan, indicating genetic isolation and a high cumulative level of autozygosity. Genotyping with eight Y-chromosome STRs resulted in the construction of six haplotypes, one each for the Awan and the Khattar but four for the Rajpoot, suggesting marked variation in the patterns of male founder effects in the history of each community. The lower than expected levels of homozygosity observed at a number of loci may be indicative of cosegregation of the STRs with nearby early development genes subject to selection.

Alleles↗
PubMed2000

The effect of birth interval on malnutrition in Bangladeshi infants and young children.

This study was undertaken to investigate the independent effect of the length of birth interval on malnutrition in infants, and children aged 6-39 months. Data for this study were drawn from a post-flood survey conducted during October-December 1988 at Sirajganj of the Sirajgani district and at Gopalpur of the Tangail district in Bangladesh. The survey recorded the individual weights of 1887 children. Cross-tabulations and logistic regression procedures were applied to analyse the data. The proportion of children whose weight-for-age was below 70% (moderate-to-severely malnourished) and 60% (severely malnourished) of the NCHS median was tabulated against various durations of previous and subsequent birth intervals. The odds of being moderately or severely malnourished were computed for various birth intervals, controlling for: the number of older surviving siblings; maternal education and age; housing area (a proxy for wealth); age and sex of the index child; and the prevalence of diarrhoea in the previous 2 weeks for the index child. About one-third of infants and young children were moderately malnourished and 15% were severely malnourished. The proportion of children who were under 60% weight-for-age decreased with the increase in the length of the subsequent birth interval, maternal education and housing area. The proportion of malnourished children increased with the number of older surviving children. Children were at higher risk of malnutrition if they were female, their mothers were less educated, they had several siblings, and either previous or subsequent siblings were born within 24 months. This study indicates the potential importance of longer birth intervals in reducing malnutrition in children.

Adult↗
PubMed2000

Lupene-type triterpenes from Periploca aphylla.

Two new lupane derivatives, 3beta,6alpha-dihydroxylup-20(29)-ene (1) and 6alpha-hydroxylup-20(29)-en-3beta-octadecanoate (2), have been isolated from the stems of Periploca aphylla, in addition to beta-sitosterol and lupeol. The structures of 1 and 2 were determined by spectral and chemical methods. Compound 1 showed strong inhibition of alpha-glucosidase type VI and a moderate antibacterial activity.

Bacillus cereus↗
PubMed2000

Effects of pH and dose on nasal absorption of scopolamine hydrobromide in human subjects.

PURPOSE: The present study was conducted to evaluate the effects of formulation pH and dose on nasal absorption of scopolamine hydrobromide, the single most effective drug available for the prevention of nausea and vomiting induced by motion sickness. METHODS: Human subjects received scopolamine nasally at a dose of 0.2 mg/0.05 mL or 0.4 mg/0.10 mL, blood samples were collected at different time points, and plasma scopolamine concentrations were determined by LC-MS/MS. RESULTS: Following administration of a 0.2 mg dose, the average Cmax values were found to be 262+/-118, 419+/-161, and 488+/-331 pg/ mL for pH 4.0, 7.0, and 9.0 formulations, respectively. At the 0.4 mg dose the average Cmax values were found to be 503+/-199, 933+/-449, and 1,308+/-473 pg/mL for pH 4.0, 7.0, and 9.0 formulations, respectively. At a 0.2 mg dose, the AUC values were found to be 23,208+/-6,824, 29,145+/-9,225, and 25,721+/-5,294 pg x min/mL for formulation pH 4.0, 7.0, and 9.0, respectively. At a 0.4 mg dose, the average AUC value was found to be high for pH 9.0 formulation (70,740+/-29,381 pg x min/mL) as compared to those of pH 4.0 (59,573+/-13,700 pg x min/mL) and pH 7.0 (55,298+/-17,305 pg x min/mL) formulations. Both the Cmax and AUC values were almost doubled with doubling the dose. On the other hand, the average Tmax, values decreased linearly with a decrease in formulation pH at both doses. For example, at a 0.4 mg dose, the average Tmax values were 26.7+/-5.8, 15.0+/-10.0, and 8.8+/-2.5 minutes at formulation pH 4.0, 7.0, and 9.0, respectively. CONCLUSIONS: Nasal absorption of scopolamine hydrobromide in human subjects increased substantially with increases in formulation pH and dose.

Absorption↗
PubMed2000

Myrica nagi attenuates cumene hydroperoxide-induced cutaneous oxidative stress and toxicity in Swiss albino mice.

In recent years, considerable efforts have been made to identify new chemopreventive agents which could be useful for man. Myrica nagi, a subtropical shrub, has been shown to possess significant activity against hepatotoxicity and other pharmacological and physiological disorders. We have shown a chemopreventive effect of Myrica nagi on cumene hydroperoxide-induced cutaneous oxidative stress and toxicity in mice. Cumene hydroperoxide treatment at a dose level of 30 mg/animal/0.2 ml acetone enhances susceptibility of cutaneous microsomal membrane for iron-ascorbate-induced lipid peroxidation and induction of xanthine oxidase activity which are accompanied by decrease in the activities of cutaneous antioxidant enzymes such as catalase, glutathione peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase and depletion in the level of cutaneous glutathione. Parallel to these changes a sharp decrease in the activities of phase II metabolizing enzymes such as glutathione S-transferase and quinone reductase has been observed. Application of Myrica nagi at doses of 2.0 mg and 4.0 mg/kg body weight in acetone prior to that of cumene hydroperoxide (30 mg/animal/0.2 ml acetone) treatment resulted in significant inhibition of cumene hydroperoxide-induced cutaneous oxidative stress and toxicity in a dose-dependent manner. Enhanced susceptibility of cutaneous microsomal membrane for lipid peroxidation induced by iron ascorbate and xanthine oxidase activities were significantly reduced (P<0.05). In addition the depleted level of glutathione, the inhibited activities of antioxidants, and phase II metabolizing enzymes were recovered to a significant level (P<0.05). The protective effect of Myrica nagi was dose-dependent. In summary our data suggest that Myrica nagi is an effective chemopreventive agent in skin and capable of ameliorating cumene hydroperoxide-induced cutaneous oxidative stress and toxicity.

Animals↗
PubMed2000

Multiple P2Y receptor subtypes in the apical membranes of polarized epithelial cells.

Apical ATP, ATP, UTP and UDP evoked transient increases in short circuit current (I(SC), a direct measure of transepithelial ion transport) in confluent Caco-2 cells grown on permeable supports. These responses were mediated by a population of at least three pharmacologically distinct receptors. Experiments using cells grown on glass coverslips showed that ATP and UTP consistently increased intracellular free calcium ([Ca(2+)](i)) whilst sensitivity to UDP was variable. Cross desensitization experiments suggested that the responses to UTP and ATP were mediated by a common receptor population. Messenger RNA transcripts corresponding to the P2Y(2), P2Y(4) and P2Y(6) receptors genes were detected in cells grown on Transwell membranes by the reverse transcriptase - polymerase chain reaction. Identical results were obtained for cells grown on glass. Experiments in which I(SC) and [Ca(2+)](i) were monitored simultaneously in cells on Transwell membranes, confirmed that apical ATP and UTP increased both parameters and showed that the UDP-evoked increase in I(SC) was accompanied by a [Ca(2+)](i)-signal. Ionomycin consistently increased [Ca(2+)](i) in such polarized cells but caused no discernible change in I(SC). However, subsequent application of apical ATP or UTP evoked a small rise in I(SC) but no rise in [Ca(2+)](i). UDP evoked no such response. As well as evoking increases in [Ca(2+)](i), the ATP/UTP-sensitive receptors present in Caco-2 cells thus allow direct control over ion channels in the apical membrane. The UDP-sensitive receptors, however, appear to simply evoke a rise in [Ca(2+)](i).

Adenosine Triphosphate↗