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Biomedical subjects

S Ahmed

Publications and source records attributed to S Ahmed.

At least 307 records · Page 17Linked to original sources
PubMed1997

Interactions of aldosterone antagonist diuretics with human serum proteins.

PURPOSE: The purpose of this study was to investigate the binding mechanism of aldosterone antagonist diuretics with human serum proteins, human serum albumin (HSA) and alpha 1-acid glycoprotein (AGP), as well as to identify the binding sites of the drugs on these proteins. METHODS: Binding activities of spironolactone (SP) and its pharmacologically active metabolite canrenone (CR) to serum and serum protein were examined by ultrafiltration and spectroscopic techniques. The data for the binding of these drugs to HSA were analyzed on the basis of a theoretical model of simultaneous binding of the ligands. RESULTS: The binding percentages of antagonist diuretics SP and CR to human serum proteins were 88.0% and 99.2%, respectively, at therapeutic concentrations. SP bound strongly only to HSA. In addition, the displacement results found using fluorescent probes and ultrafiltration methods demonstrated that SP bound to site I, particularly to the warfarin region on HSA, and to the basic binding site on AGP, while CR bound to the warfarin region on HSA. CONCLUSIONS: The limited results presented here stress the need for caution on coadministration of acidic drugs which bind to the warfarin region on HSA and basic drugs which bind to AGP with SP and its metabolite CR.

Blood Proteins↗
PubMed1997

Comparison of catecholamine and pressor effects in peribulbar and retrobulbar anaesthesia in cataract surgery.

Peribulbar anaesthesia is now established as an alternative to retrobulbar anaesthesia for cataract surgery. However, the larger volume of anaesthetic solution in the extraconal orbit with the peribulbar technique might carry a higher risk of systemic side-effects. To assess this risk we carried out a prospective randomised comparison of plasma catecholamine and pressor effects between the two methods of anaesthesia in 40 patients. Plasma adrenaline and noradrenaline, heart rate, blood pressure, pain and anxiety were documented before and after local anaesthesia and during surgery. There were no statistically significant differences between the responses of the two groups. Both groups demonstrated a statistically significant rise in plasma adrenaline and heart rate. However, this change was minimal compared with the effects reported after severe stress or general anaesthesia, emphasising the importance of allaying patient anxiety during local anaesthesia. We have therefore shown that the larger volume of extraconal orbital anaesthetic solution with the peribulbar technique produces no greater risk of systemic pressor effects.

Anesthesia, Local↗
PubMed1997

Gender reversal in 46XX congenital virilizing adrenal hyperplasia.

OBJECTIVE: To review the results of gender reversal in six patients with 46XX congenital virilizing adrenal hyperplasia (CVAH). PATIENTS AND METHODS: Fifty-one patients with 46XX CVAH were seen in an 8 year period; 45 were managed by conventional feminizing genitoplasty, but six underwent gender reversal and were managed as males. The clinical decision for gender reversal was made after appropriate counselling and was based primarily on parental choice, this being influenced significantly by a delayed diagnosis in four patients. Surgical management consisted of gonadectomy, excision of Müllerian structures and staged hypospadias repair/ chordee correction in four patients, and circumcision in two completely masculinized children. RESULTS: All six boys are well adjusted to their gender of rearing, with ages ranging from 3 years to 16.5 years (mean 8.5) at the time of review. Two children have normal penises and four have a satisfactory result after two-stage repair of hypospadias/chordee. CONCLUSION: Most patients with 46XX CVAH are preferably raised as females and require a feminizing genitoplasty. However, the clinical decision may be influenced by many factors, including delay in diagnosis, social bias and the premium on male rearing in certain communities. When male rearing is chosen, early gonadectomy and excision of Müllerian structures, together with staged hypospadias repair, gives satisfactory results.

Adolescent↗
PubMed1997

Buccal mucosal graft for secondary hypospadias repair and urethral replacement.

OBJECTIVE: To assess the effectiveness of buccal mucosa in the treatment of complex hypospadias. PATIENTS AND METHODS: Seventeen patients had an onlay patch of buccal mucosa to reconstruct the urethra after failed previous surgery; five had a tubed buccal mucosal graft as an urethral replacement in the 'primary' repair of severe hypospadias. RESULTS: There were no complications in 19 patients; two developed fistulae and one a stricture due to graft narrowing. There were no meatal complications. CONCLUSION: Buccal mucosa taken from the inner aspect of the lip is very suitable for reconstructing a failed hypospadias repair, especially when used as an onlay graft.

Follow-Up Studies↗
PubMed1997

Control of infection: a survey of general medical practices.

BACKGROUND: The aims of the study were (1) to assess current infection control practice within general medical practices and establish a base line; (2) to identify potential infection control problems; (3) to assess the need for local infection control guidelines or standards related to general medical practice; (4) to assess the need for educational provision. METHODS: A survey was carried out, using questionnaire and structured interviews, of all general practices (92) within a Health Board area with a patient population of 561,300. RESULTS: Forty two (46 per cent) practices participated, serving 67 per cent of the patient population. Only three (7 per cent) practices had written infection control policies and only six (14 per cent) provided training on the subject. Thirty (71 per cent) practices had autoclaves; however, performance monitoring was poor. The majority of high-risk instruments were adequately decontaminated; of the medium-risk instruments, the auriscope speculum was the item most frequently inadequately treated [36 practices (88 per cent)]. Deficiencies were identified in treatment of blood spillage, and protective clothing provision was variable. The majority, 40 (95 per cent) practices, had systems to deal with clinical waste; however, only two (5 per cent) reported use of BS7320 sharps containers on domiciliary visits. Despite the recognized dangers, 23 (55 per cent) practices resheathed needles and only six (14 per cent) had first aid guidance for needlestick injuries. Only eight (19 per cent) practices knew and recorded staff immunity to hepatitis B following vaccination. CONCLUSIONS: Some deficiencies in infection control practice were identified and the need for policy guidance and staff training was highlighted.

Family Practice↗
PubMed1997

An evaluation of the role of suction rectal biopsy in the diagnosis of intestinal neuronal dysplasia.

BACKGROUND: German pathologists have developed a consensus for histological features of intestinal neuronal dysplasia. METHODS: A blind reevaluation of ganglionic suction rectal biopsies from infants and children who initially presented with symptoms of intestinal dysmotility was made. RESULTS: 84 of 411 specimens had sufficient depth of submucosa for adequate assessment. Questionnaires or clinical interviews were employed 3-5 years after biopsy in these 84 patients to assess the relationship between histological changes and persistent symptomology. Eighteen children were lost to follow-up, 4 others had Hirschsprung's disease the study biopsy specimen having been taken from the pulled-through bowel after surgical resection of the aganglionic segment. The remaining 62 patients were divided into three groups. There were six patients in group A (both obligatory criteria) and 28 in group B (nonessential, or just one of the obligatory criteria), and 28 in group C (normal appearances). On follow-up, two of the 28 (7%) in group B, and six of the 28 (21%) in group C had persistent dysmotility symptoms. CONCLUSIONS: Histological criteria of the consensus of German Pathologists for intestinal neuronal dysplasia was unhelpful in predicting the clinical outcome and therefore, should not influence clinical management. As one of the obligatory criteria, hyperplasia of the submucosal plexus was significantly more common in neonates (< 4 weeks), it is concluded that this is an age-related variation.

Acetylcholinesterase↗
PubMed1997

Rho family GTPases and neuronal growth cone remodelling: relationship between increased complexity induced by Cdc42Hs, Rac1, and acetylcholine and collapse induced by RhoA and lysophosphatidic acid.

Rho family GTPases have been assigned important roles in the formation of actin-based morphologies in nonneuronal cells. Here we show that microinjection of Cdc42Hs and Rac1 promoted formation of filopodia and lamellipodia in N1E-115 neuroblastoma growth cones and along neurites. These actin-containing structures were also induced by injection of Clostridium botulinum C3 exoenzyme, which abolishes RhoA-mediated functions such as neurite retraction. The C3 response was inhibited by coinjection with the dominant negative mutant Cdc42Hs(T17N), while the Cdc42Hs response could be competed by coinjection with RhoA. We also demonstrate that the neurotransmitter acetylcholine (ACh) can induce filopodia and lamellipodia on neuroblastoma growth cones via muscarinic ACh receptor activation, but only when applied in a concentration gradient. ACh-induced formation of filopodia and lamellipodia was inhibited by preinjection with the dominant negative mutants Cdc42Hs(T17N) and Rac1(T17N), respectively. Lysophosphatidic acid (LPA)-induced neurite retraction, which is mediated by RhoA, was inhibited by ACh, while C3 exoenzyme-mediated neurite outgrowth was inhibited by injection with Cdc42Hs(T17N) or Rac1(T17N). Together these results suggest that there is competition between the ACh- and LPA-induced morphological pathways mediated by Cdc42Hs and/or Rac1 and by RhoA, leading to either neurite development or collapse.

ADP Ribose Transferases↗
PubMed1997

Incidence of insulin dependent diabetes mellitus in Karachi, Pakistan.

OBJECTIVES: To determine the incidence of insulin dependent diabetes mellitus (IDDM) among children aged up to 16 years residing in the city of Karachi, Pakistan, during the five years from 1989 to 1993. DESIGN: Retrospective study of incidence using hospital and clinic records. SETTING: The city of Karachi, Pakistan. SUBJECTS: Children satisfying standard criteria for the diagnosis of IDDM, attending treatment facilities for the first time during the study period. MAIN OUTCOME MEASURES: The incidence of IDDM in this population and its variation by age and sex. RESULTS: The incidence of IDDM in this population is 1.02/100000 per year, which is one of the lowest incidence rates yet reported. CONCLUSIONS: The very low incidence of IDDM, contrasted with the substantially higher incidence among migrants, supports the view that environmental factors are the major determinants of variations in the incidence of this condition between populations.

Adolescent↗
PubMed1997

The mechanism of a P-450 enzyme-aromatase; a molecular modelling perspective for the removal of the C(19) methyl and aromatisation of the steroid A ring.

The three possible mechanisms for the final step of aromatisation, as proposed by Wright and Akhtar, are studied using a molecular modelling approach utilising the 'substrate-heme complex' previously reported. The study considers the three mechanisms from a geometric point of view and concludes that only a ferroxy radical is involved in all three steps of aromatase action and not the mixture of both ferroxy and peroxy as previously suggested. The study also suggests that an alternative peroxy-based mechanism is unlikely due to the distances between reacting species. An alternative theoretical mechanism, which circumvents the production of the CHO. radical (regarded to be too small to be retained within the active site) for the final step of aromatisation is suggested involving the concerted breakup of the iron-formate complex together with hydrogen abstraction from C(1) of 3-hydroxy-estra-2,4-diene-17-one, resulting in oestrone and formic acid.

Androgens↗
PubMed1997

Evaluation of culture, histological examination, serology and the rapid urease test for diagnosis of Helicobacter pylori in patients with dyspepsia in Bangladesh.

Helicobacter pylori, a gram-negative, microaerophilic bacterium, has been established to have a causal association with chronic gastritis, peptic ulcer, gastric adenocarcinoma, and low-grade lymphoma. The present study was undertaken to evaluate the efficacy of culture, histological examination, the rapid urease test, and serology for the diagnosis of H. pylori infection. A total of 45 consecutive subjects with various upper gastrointestinal symptoms were included in this study. The rates of diagnosis of H. pylori infection were 51.1%, 55.6%, 82.2%, and 93.3%, by culture, rapid urease test (RUT), histological examination, and serology, respectively. The sensitivity, specificity, and positive and negative predictive values were 95.5%, 82.6%, 84.0%, and 95.0%, respectively for RUT; 95.5%, 30.4%, 56.8%, and 87.5% for histological examination; 100%, 13.6%, 54.8% and 100% for serology.

Adult↗
PubMed1997

Variations in living donor graft rates by dialysis clinic: effect on outcome and cost of chronic renal failure therapy.

OBJECT: Examination of nephrology practice variations in living donor renal grafts to determine their influence on organ supply, quality, and cost of chronic renal failure therapy. MATERIALS: Saskatchewan chronic dialysis, cadaveric, and living donor renal grafts in 1983-1994 inclusive. RESULTS: Saskatchewan has three dialysis (I, II, III) and one transplant clinic. In the period the renal graft incidences/million population by these dialysis clinics by organ source were; Cadaveric: 23.1, 23.2, 21.1 (p = ns). Living: 5.4, 21.7, 8.3 (I or III vs II p < 0.000, I vs III p < 0.061). Total: 28.7, 44.7, 29.4. Living donor series A is 79 grafts in patients under age 60 with primary renal disease. Series B is 20 grafts in patients with secondary renal disease or over age 59. Series A ten-year actuarial patient survival is 92% and B 44%. Series A ten-year actuarial graft survival (including regrafts) is 77% and B 39%. Rehabilitation rate in patients with functioning grafts is 88.5%. Province-wide extension of the Clinic II living-donor graft rate in 1983-1994 would have produced 160 more renal grafts or 59% of those receiving chronic dialysis in 1994. The annual maintenance for a graft with the initial grafting cost taken over five years was $10,825 and the dialysis cost $40,100. CONCLUSIONS: (1) nephrology practice variations caused a 2.5-4.0-fold difference in living donor renal graft rates, indicating patient education by the attending nephrologist influences the living donor transplantation rate, (2) with such education the combined living donor and the cadaveric organ supply virtually meets graft demand, (3) living donor renal grafts yield a better quantity and quality of life and better cost control than dialysis with their annual cost being one-quarter that for dialysis.

Actuarial Analysis↗
PubMed1997

Use of betel quid and cigarettes among Bangladeshi patients in an inner-city practice: prevalence and knowledge of health effects.

BACKGROUND: Betel quid chewing, often combined with tobacco chewing, is a common habit in the Indian subcontinent. It is associated with the development of malignancy of the oral mucosa and foregut. Among Asian communities in the United Kingdom (UK), Bangladeshis are particularly likely to retain this habit. AIM: To investigate the prevalence of betel quid chewing, smoking, and knowledge of health hazards associated with these habits among the Bangladeshi population in an east London general practice. METHOD: A bilingual postal questionnaire to all 306 adults (25 years and over) identified as being of Bangladeshi origin within one practice in east London. RESULTS: The questionnaire response rate was 46%. The prevalence of betel quid chewing was over 80% with no sex difference. Men were more likely to smoke tobacco than women (men = 57%, women = 11%, X2 = 33.3, P < 0.001), but over half the women added tobacco to their quid for chewing. Whereas over 80% of both male and female respondents identified the health risk of smoking, only one third identified oral cancer as a risk. In all, 25% of respondents started chewing in the UK. CONCLUSIONS: The low response rate is discussed. The findings indicate that the majority of Bangladeshi respondents are unaware of the health risks of a common social habit, although well informed about smoking risks. A government health warning should be introduced for betel quid sold in the UK.

Adult↗