Biomedical subjects
Publications and source records attributed to M A Malik.
A new approach to the one-step synthesis of cadmium selenide (CdSe) quantum dots is reported using the air stable complex cadmium imino-bis(diisopropylphosphine selenide); the ligand is readily prepared from elemental selenium and the precursor, quantum dots of comparable quality to those prepared by conventional methods are obtained.
OBJECTIVE: To investigate whether estimation of thyrotrophin (TSH) and thyroxine (T4) is significant to assess the thyroid status of diabetic patients. MATERIALS AND METHODS: Fifty patients with type 1 diabetes (25 male and 25 female) aged 9-50 years were included. The mean duration of diabetes was 6.7 +/- 4.3 years. Clinically they were not suffering from any systemic disease or endocrine ailment. Twenty-six, age and sex matched, normal controls were also included. The TSH and and T4 were estimated in the sera of all the subjects using the commercially available ELISA kits. RESULTS: The mean +/- SD concentration of TSH was raised significantly (p < 0.001) in the patients as compared to the controls, whereas the T4 concentration was comparable. Furthermore, 30% diabetics showed significantly elevated TSH concentration than the controls. CONCLUSION: It is proposed that the estimation of TSH in the patients with type 1 diabetes may be useful in the early identification of thyroid dysfunction.
This study determined whether the effect of all-trans-retinoic acid (t-RA) on markers of cholinergic differentiation in a murine septal cell line, SN56.B5.G4, differed depending upon the cell's proliferative status. To develop a model of non-proliferating cells, aphidicolin, a DNA alpha-polymerase inhibitor, was used. Cessation of proliferation by aphidicolin increased intracellular choline and acetylcholine (ACh) levels in the absence of change to choline acetyltransferase (ChAT) activity and mRNA and vesicular ACh transporter (VAChT) mRNA. Importantly, the response to t-RA differed depending upon proliferative status. Consistent with previous reports, t-RA increased ChAT and VAChT mRNA, ChAT activity and intracellular ACh levels in proliferating SN56 cells with no effect on intracellular choline levels. When cells were treated with t-RA while undergoing proliferative arrest, an additive effect of combined treatment was observed on ACh levels; nevertheless, this was only accompanied by an increase in choline levels, VAChT and ChAT mRNAs, but not ChAT activity. Indeed, aphidicolin treatment completely suppressed the t-RA-induced increase in ChAT activity observed in proliferating cells. To explore the response to t-RA in post-mitotic cells, a sequential treatment of aphidicolin and t-RA was employed. t-RA treatment was ineffective in increasing ACh and choline levels, over and above that observed with the aphidicolin treatment alone. Comparable to the combined treatment, sequential treatment lead to an increase in ChAT mRNA without any increase in ChAT activity. In conclusion, both the magnitude and the mechanism(s) of action whereby t-RA enhances the cholinergic phenotype of SN56 cells is dependent upon the cell's proliferative status.
The photochemical reactions of bis(diethyl-diselenocarbamato)copper(II), Cu(Et2dsc)2, complex have been studied in toluene, CH2Cl2, CHCl3 and chloroalkane/EtOH mixed solvents. Charge-transfer irradiation induces intramolecular oxidation of the ligand and reduction of copper(II) to copper(I) as evidenced by EPR and UV-Vis spectra of the complex as well as quantum yield results. When photolysis is carried out in CHCl3 or CH2Cl2 or in the solvent mixture CHCl3/EtOH resp. CH2Cl2/EtOH of lower than 1:1 EtOH content, the primary photoproduct CuI(Et2dsc) is further oxidised in a dark reaction with the chloroalkane producing the corresponding paramagnetic mixed-ligand CuII(Et2dsc)Cl complex in equilibrium with its chloride-bridged and EPR silent, dimeric form Cu2(Et2dsc)2Cl2. At low concentration of EtOH the equilibrium is shifted to the dimeric form whereas at higher than 1:1 EtOH content in the mixed solvent CHCl3/EtOH it is shifted to CuII(Et2dsc)Cl. A reaction mechanism is proposed and the role of ethanol is discussed.
After recovery from persistent diarrhea, some children have recurrent episodes of diarrhea and associated problems. We undertook this study to identify the risk factors responsible for this relapse. All patients reporting at 1 month follow up since discharge, with > 7 diarrheal days, or inadequate weight gain compared to the weight at discharge, constituted the failure group. All others constituted the non-failure group. Various risk factors were studied in 21 cases (failure group), and 42 controls (non-failure group). Univariate analysis revealed a significant association of hospital stay < 5 days (OR 10.6; 95% CI 3.13-36), working mothers (OR 8.5; 95% CI 2.5-27), poor socioeconomic status (OR 4.5; 95% CI 1.4-14) and presence of younger sibling (OR 3.69, 95% CI 1.1-12.6) with failed outcome. On logistic regression analysis, only hospital stay < 5 days (OR 11.7; 95% CI 1.02-134.68) and female children (OR 17.65; 95% CI 1.26-246) remained significant. We therefore conclude, that a short hospital stay, limited optimal contact and limited health education adversely affects the outcome. Pediatricians should be more cautious while managing female children.
Age may have a different contribution to normal lung function values in those aged less than 25 years, as compared to older individuals. We report regression equations predicting ventilatory parameters in this age group, as none have been reported from Pakistan. The study was conducted on students of King Edward Medical College Lahore, Pakistan. Participants had never smoked and reported no respiratory symptoms. In addition to anthropometric data, forced expiratory volume in 1 sec (FEV1), forced vital capacity (FVC), peak expiratory flow (PEF) and forced expiratory flow at 50% of FVC (FEF50) were measured. Equations predicting normal values of these parameters were derived using SPSS (Chicago, Illinois, U.S.A.) P < or = 0.05 was treated as statistically significant. Of the students, 519 took part in the study. All four parameters correlated significantly (P < 0.001) and positively with height. FEF50 had a negative correlation with age in both sexes (P < 0.05). The correlation of other parameters with age was variable and not statistically significant. On multiple regression, height featured as an independent predictor in equations for all parameters. The contribution of age as an independent predictor of ventilatory function was, once again, variable. Independent variables were retained in the raw form as their transformation did not improve the goodness of fit of the derived equations. Only height and age emerged as independent predictors of ventilatory function. Values derived from the equations presented in this study were less than those for height and age matched white Caucasians. Such differences were greater than the 'Asian correction factors'.
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Lead exposure was assessed in a random cohort of 70 male papier mâché workers and compared with 35 age and sex matched controls. Blood-lead levels in workers were significantly higher than in controls (Mean 68.07 +/- 44.64 ug/dl vs 25.52 +/- 16.56 ug/dl respectively; P < 0.001). Urinary lead was also higher in workers (128.53 +/- 52.61 ug/l) compared to controls (91.18 +/- 27.06, P < 0.001), but excretion of urinary coproporphyrin in the two groups was not significantly different (102.78 +/- 153.42 vs 70.03 +/- 27.06 ug/l, P > 0.05). Blood levels bore a significant correlation with age but did not bear any correlation with the duration of exposure. Various modes of exposure to lead included hand mixing of paints, skin application of the paint to match shades and making point of the brush using lips and the tongue.
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Following the identification of an index case of occupational asthma, we assessed the respiratory morbidity in 12 workers exposed to aliphatic polyamines in a chemical factory and in 60 unexposed workers in three other workplaces. Many amine workers reported symptoms of chronic cough (7/12), chronic phlegm (9/12), wheezing (4/12) and exertional breathlessness (3/12). These were significantly more frequent in exposed than in unexposed workers (P < 0.01). They also had significantly greater diurnal variation in peak expiratory flow rates (DV-PEFR) than the unexposed workers (P < 0.01). All four amine workers with wheezing reported onset of symptoms after employment at the factory, and all had DV-PEFR greater than 15%, compared to only one control worker (P < 0.01). A second case of occupational asthma was confirmed by bronchial challenge test. The study indicated a very high risk of asthma and chronic airways disease and a need for stringent measures to protect the health of industrial workers exposed to aliphatic amines in Singapore.
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Thyroid microsomal antibody (MsAb) was estimated in 48 patients with Graves' disease (15 newly diagnosed, 15 on drugs for about 4 weeks and 18 euthyroid with drug treatment) and twenty age and sex matched controls. The diagnosis of Graves' disease (GD) was based on clinical history, physical examination and thyroid function tests, viz. 131I uptake, thyroid scintigram and serum T3, T4 and TSH levels. MSAb was positive in 93.3% of newly diagnosed as well as hyperthyroid GD patients on drugs. Eighty-three percent euthyroid GD patients and 20% normal controls also showed MSAb positivity. The titres of newly diagnosed patients were significantly raised (P < 0.05) than those of euthyroid patients and controls indicating the diagnostic as well as prognostic significance of MSAb in Graves' disease.
The morphological responses of individual osteoblasts as they attached and spread on hydroxyapatite, bovine bone, alumina with rough and polished surfaces, and tissue culture polystyrene in vitro were examined with scanning electron microscopy. Depending on the surface tested two different morphological sequences were observed during 2 h of adhesion. On alumina, both rough and smooth, bone, and tissue culture polystyrene the cells were round after 0.5 h, and spread radially during the next 1.5 h until they were almost flat, with a nuclear bulge. On hydroxyapatite, however, the cells were flat and circular at 0.5 h, and the edge of the cytoplasm was hardly discernable. This morphology did not change much during the subsequent 1.5 h. The observed cellular morphological response may be related to the bioreactivity of hydroxyapatite.
Glycaemic index of local staple foods was determined. In first phase, the post prandial blood glucose response of isocaloric portion of wheat chapati and gram flour (baisen) chapati, were compared in 11 type II diabetic patients as a part of mixed meal in fasting state, alternately. The glycaemic index of baisen chapati was 39 as compared with wheat chapati. In second phase of the study, 22 type II diabetic patients were given isocaloric portions of wheat chapati and boiled rice as a part of mixed meal alternately. The glycaemic index of rice was 98 as compared with wheat chapati. This study favours the belief that baisen chapati is better and refutes that rice is bad for diabetics. It also upholds that glycaemic index is useful for planning a diabetic diet.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.