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Biomedical subjects

N Khan

Publications and source records attributed to N Khan.

251 records · Page 14Linked to original sources
PubMedDate not supplied

Prevalence and clinical presentation of glucose-6-phosphate dehydrogenase deficiency in Pakistani Pathan and Afghan refugee communities in Pakistan; implications for the use of primaquine in regional malaria control programmes.

Glucose-6-phosphate dehydrogenase (G-6-PD) deficiency surveys in Afghan refugees and a local community in the North-West Frontier Province, Pakistan, showed that this trait was most common among Pathan and Uzbak refugees (15.8% and 9.1% respectively). The prevalence among Pakistani Pathans was 7.0%, and that in Tajik and Turkoman refugees was 2.9% and 2.1% respectively. Hospital studies showed that the type of G-6-PD deficiency in Pathans could cause severe haemolytic crises. The potentially fatal side effects of primaquine treatment in the Pathan communities, and the high risk of re-infection, render the anti-relapse treatment policy for Plasmodium vivax obsolete. However, epidemic conditions of P. falciparum malaria may justify the use of primaquine as a gametocidal drug, administered as a single dose, during the transmission season. These findings necessitate revision of the recommendations for the use of primaquine in the area.

Adolescent↗
PubMedDate not supplied

Linked parallel synthesis and MTT bioassay screening of substituted chalcones.

A 644-membered library of chalcones was prepared by parallel synthesis using the Claisen-Schmidt base-catalyzed aldol condensation of substituted acetophenones and benzaldehydes. The cytotoxicity of these chalcones was conveniently determined upon the crude products directly in 96-well microtiter test plates by the conventional MTT assay. This method revealed seven chalcones of IC(50) less than 1 microM of which 4'-hydroxy-2,4,6,3'-tetramethoxychalcone (5a) was the most active [IC(50) (K562), 30 nM]; it causes cell cycle arrest at the G(2)/M point and binds to tubulin at the colchicine binding site.

Acetophenones↗
PubMedDate not supplied

Lesions and identification of crystalline precipitates of glycoprotein IIb-IIIa antagonists in the rat kidney.

Two glycoprotein IIb-IIIa antagonists (xemilofiban, SC-54684A, and orbofiban, SC-57099B), which are platelet aggregation inhibitors, caused crystalline precipitates in the kidney tubules of rats at high dosages. Dogs were not affected. Depending on the degree of the precipitation, which was dosage dependent, and the location, which differed somewhat between the two compounds, the lesions varied from acute obstruction with tubule cell necrosis, nephron dilation, and sudden death with no inflammation to severe chronic pyogranulomatous inflammation. In order to understand the relevance of the lesions, it was important to identify the precipitates. This was technically challenging because the crystals were water soluble (dissolving in routine fixing and staining techniques) and were present in insufficient quantity to physically isolate. Techniques were devised to evaluate the crystals in situ in unstained frozen sections prepared without directly embedding the tissues in supporting medium, which interfered with the analyses. The crystals were analyzed in situ by infrared and Raman spectroscopy and time-of-flight secondary ion mass spectroscopy (TOF-SIMS). Uroliths found in the renal pelvis of one animal were analyzed by liquid chromatography/mass spectrometry. The resulting spectra showed that the crystals were the de-esterified acids of the parent compounds. This knowledge allowed us to predict that the crystalline precipitates would not be a hazard to humans because of the large multiples of the human dosage at which they occurred and because of differences in renal physiology between rats, dogs, and humans.

Alanine↗
PubMedDate not supplied

Barriers to control of blood glucose in diabetes mellitus.

The purpose of this study was to characterize the barriers to tight control of diabetes mellitus. The study collected data from multiple sources at a primary health care clinic in an academic teaching hospital serving an urban population, including patients' charts, structured interviews with patients, a survey of physicians' general perspectives and beliefs concerning diabetes mellitus, and a physician's structured review of barriers to tight control for individual patients. One hundred thirty-five patients with scheduled appointments were eligible for the study, of whom 94% had had a recent hemoglobin A1C (HbA1C). Seventy-seven of 88 patients (88%) who presented for their appointments consented to the interview, 48 of 50 providers (96%) returned useable surveys, and providers completed individual assessments for 96 patients (71%). Patients had a mean age of 61 years, an average of 7.60 diagnoses, and an average of 8.96 prescriptions. Their diabetes control was less than ideal, with less than 15% having normal or near normal control and almost a quarter having poor control. Correlations of HbA1C with age and show rate were seen. Physicians' assessments showed that motivation and understanding of diabetes and compliance with diet and medications correlated with diabetes control. Neither patient knowledge nor physician knowledge appeared to be a problem, nor did either correlate with diabetes control. The number of barriers to control were many, with over half of the patients having five or more barriers. Tight control of blood glucose is felt to be an important aspect of quality care for diabetic patients. In this study, a representative sample of diabetic patients had less than ideal diabetes control. This population was receiving their care in an urban setting and had many comorbid illnesses and many barriers to control. Age, motivation, understanding of the disease, show rate, and compliance with diet and medications had statistical correlations with diabetes control. In order to improve the quality of care for diabetic patients, barriers to care must be addressed.

Adult↗
PubMedDate not supplied

Antioxidant status of the hypertrophic heart of Dahl hypertensive rat as a model for evaluation of antioxidants.

Development of hypertension, myocardial hypertrophy and the cardiac antioxidant status of male Dahl salt-sensitive (DSS) genetically hypertensive rats was evaluated and compared to that of normotensive Dahl salt-resistant (DSR) controls. In order to obtain exaggerated and more severe hypertension, half of the animals (10 per group) were Na loaded (8% NaCl diet) for 6 weeks. The myocardial antioxidant status was estimated in tissue homogenates on the basis of tissue glutathione (GSH), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). The results showed that 6 weeks of hypertension resulted in left ventricle myocardial hypertrophy, documented by weight, morphometry and morphological changes. The compromised myocardial antioxidant status of the DSS rats was defined by significantly decreased GSH-Px and glutathione activity (13% and 41%, respectively) as compared to DSR rats. SOD in DSS myocardium was increased by 47% compared to that in DSR myocardium, an effect that is considered a compensatory mechanism to the oxidative stress. All of the above changes were exaggerated by NaCl loading. It was concluded that DSS rats, on either a normal or high NaCl diet, displayed decreased antioxidant capacity, which is most likely genetically determined. Before the Dahl rat can be considered as a suitable model for testing new cardiac antioxidants, a full characterization of the level of cardiac oxygen free radicals is required.

Analysis of Variance↗
PubMedDate not supplied

Thyroid function in haemodialysed patients of Gassim, Saudi Arabia: TRH stimulation.

To study the hypophysical-pituitary-thyroid axis in Saudi patients on (RDT), 200 units of TRH were given intravenously predialysis to each of 21 such subjects. As expected (TSH) rose promptly within 30 minutes followed by a gentle decline at 60 minutes. A more gentle rise was also noted in T3 which continued for the 60 minutes of observation. Rather unexpectedly, T4 level was noted to show a reciprocal decline. To our knowledge, this pattern has not been defined in literature. In 12 patients (GH) was noted to rise promptly within 30 minutes followed by a gentle decline at 60 minutes. (LH) and (FSH) did not follow any definite pattern as observed for T3 and T4. Since the oral preparation of TRH is now available, can (TRH) be effectively used to treat renal dwarfism?

Follicle Stimulating Hormone↗
PubMedDate not supplied

Caries prevalence, oral hygiene and orthodontic status of Saudi Bedouin children.

The objectives of the study were to determine caries prevalence, oral hygiene and orthodontic status of Bedouin children in a desert around Al-Qasseem Region of Saudi Arabia. One hundred and fifty three children were examined for caries, oral hygiene and orthodontic status with mirror and explorer utilizing natural light. These children were divided into two groups for analyses. The primary dentition group consisted of 77 children, 39 (50.6%) male and 38 (49.4%) female with a mean age of 4.0 (+/- 1.4) years. The mixed dentition group consisted of 76 children, 67 (88.2%) male and 9 (11.8%) female with a mean age of 9.7 (+/- 2.9) years. In Primary dentition group, 16 (20.8%) children were caries positive and mean DMFT was 0.91 (+/- 2.42). There was a highly significant relation (p < .001) between oral hygiene and caries. In the mixed dentition group, 15 (19.7%) children were caries positive. The mean DMFT and DMFT scores for these children were 0.72 (+/- 1.96) and 0.74 (+/- 1.48) respectively. There was a significant relation (P > .01) between oral hygiene and caries. One hundred and fifty one (98.6%) children had class I molar relation and 2 (1.4%) children had class II molar relation. Anterior open bite, anterior crossbite and posterior crossbite were found in one case (0.7%) each. The caries experience of these Bedouin children was low both in terms of prevalence and severity. There was a significant relation between oral hygiene and caries. The orthodontic problems were almost nonexistent in the study population.

Arabs↗
PubMedDate not supplied

Infective endocarditis: a prospective study of 60 consecutive cases.

Sixty cases of infective endocarditis were studied prospectively between May, 1985 and December, 1988. There were 40 males and 20 females with a mean age of 28 years. Endocarditis was found on normal valves in 13 patients, on rheumatic valves in 30, on congenital lesions in 8, on prosthetic valves in 4 and on mitral valve prolapse in 5 cases. Positive blood cultures were detected in 35 patients (58%). In addition bone marrow culture was positive in 1 and valves removed on surgery grew causative organisms in eight. Thus the total culture positive cases were 44 (73%). The commonest infective organism was Streptococcus viridans. Uncommon organisms accounted for 10 cases (17%). Two dimensional echocardiography (2D-Echo) was done in all cases and vegetations were detected in 48 patients (80%). 2 D-Echo was helpful not only in the detection of vegetations but also in the demonstration of other complications of endocarditis like ring abscesses, ruptured chordae, ulceration of aortic root, interventricular septum abscess, and mitral xenograft obstruction. Early surgery was performed in 31 patients. In this group of patients severe heart failure was present in 21, embolization in 10, persistence of fever in 15 and large vegetations in 19. Of the 29 patients treated medically, 2 died. The mortality in the surgical group was seen in 5 (16%) with a mean follow-up of 15 months. The major reason for a large number of our patients undergoing surgery is the fact that this is a referral Center and patients were sent later or when there was a failure of medical treatment.

Adult↗
PubMedDate not supplied

Echocardiographic studies during stress testing using cold pressor test combined with hand grip exercise in asymptomatic patients with severe aortic regurgitation.

The aim of this study was to evaluate stress combining a cold pressor test and hand grip exercise during echocardiographic investigation of predominantly young asymptomatic patients with severe aortic regurgitation. Thirty five patients were catheterised and divided into two groups. Group A (16 cases) with abnormal ejection fraction by angiocardiography (less than 50%) and Group B (19 cases) with normal ejection fraction (greater than or equal to 50%). The above stress test altered significantly the blood pressure and heart rate in both groups. However, echocardiographic end systolic diameter, end diastolic diameter and fractional shortening were significantly worse during stress test only in Group A but not in Group B. In addition when an end systolic diameter greater than or equal to 48 mm is used as a predictor of abnormal ejection fraction, its sensitivity (100%) and specificity (83%) during stress is only marginally superior to the results obtained at rest. Similarly fractional shortening decrease of 10% or more during stress was no better than resting end systolic diameter parameter. The modified peak systolic pressure-end systolic volume slope demonstrated diminished systolic function in Group A in comparison to Group B. In conclusion, in young asymptomatic patients with severe aortic regurgitation, stress testing altered the echocardiographic parameters significantly in group A patients with abnormal ejection fraction but not in group B patients with normal ejection fraction. However, echocardiographic data during stress testing is not significantly superior to resting end systolic diameter in predicting abnormal ejection fraction.

Adult↗
PubMedDate not supplied

Long term results of valvar replacement in Kuwaitis.

The long term follow-up of 59 Kuwait citizens who underwent valve replacement is presented. There was an early mortality of 12% and late mortality of another 12% with actuarial survival of 76% at five years. These values compare well with earlier Western series. The mean age of 26 is about half that reported in the Western literature. The ratio of mitral valve involvement (pure or mixed) to aortic valve involvement is 2.5:1 indicating that rheumatic heart disease is still prevalent. However, no case was operated during rheumatic activity. Anticoagulation therapy was well tolerated among the Bedouin community with acceptable thromboembolic and bleeding complications. There was high foetal wastage with only two live births out of six pregnancies. Valve malfunctions, haemolysis and subacute bacterial endocarditis complications are also discussed and were little different from other series.

Adolescent↗
PubMedDate not supplied

Use of sweet snacks, soft drinks and fruit juices, tooth brushing and first dental visit in high DMFT 4-6 year olds of Riyadh region.

A total of 68 children, 4-6 years old and equally distributed by gender were selected for the study. Information about use of sweet snacks, soft drinks and fruit juices/drinks, tooth brushing/cleaning, and first dental visit of the children was obtained through a self-administered questionnaire completed by the parents of the selected children. Sixty (88.2%) children were given sweetened snacks. Fifty one (75%) children were using canned soft drinks and packed fruit juices. Twenty eight (41.2%) children were not brushing/cleaning their teeth. The mean age of first dental visit among the study children was 63 (S.D 16.9) months. It may be concluded that the lack of dietary discipline and good oral hygiene habits were most probably responsible for caries in these children.

Beverages↗