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Biomedical subjects

M Hasan

Publications and source records attributed to M Hasan.

At least 109 records · Page 6Linked to original sources
PubMed1989

A study on the relative bioavailability of a sustained-release formulation of diclofenac sodium.

The bioavailability of an in vitro sustained-release formulation of diclofenac sodium was compared with a conventional product in six healthy male volunteers. The administration of a single dose (100 mg) of either formulation in a crossover design revealed significant differences in the extent of absorption as assessed by AUC. The relative bioavailability of the sustained-release formulation was found to be 53% compared with the conventional product. The Cmax for the sustained release formulation (0.54 +/- 0.29 micrograms ml-1) was significantly much lower than the corresponding value for the conventional formulation (4.12 +/- 0.91). However, the tmax for the sustained release formulation (3.6 +/- 2.1 h) was not significantly different from the corresponding value for the conventional formulation (2.5 +/- 0.4 h). Although the sustained release formulation showed serum concentration-time profiles characteristic of sustained products in vivo, it failed to attain therapeutic drug levels. The in vivo results were found inconsistent with the in vitro availability of the drug.

Adult↗
PubMed1988

Dose-related neurochemical changes in the levels of gangliosides and glycogen in various regions of the rat brain and spinal cord following methyl parathion administration.

The aim of the present study was to evaluate the neurochemical changes in the levels of gangliosides and glycogen of the cerebral hemisphere, cerebellum, brain stem and spinal cord following the intraperitoneal (ip) injection of the organophosphate pesticide methyl parathion (1.0 mg, 1.5 mg and 2.0 mg/kg) to each rat of the experimental group daily for 7 days. A remarkable dose-related depletion in the concentration of gangliosides was discernible in all the regions of the CNS. Also, the contents of glycogen exhibited a decrement in different parts of the brain with all the 3 dose-schedules following methyl parathion toxicosis. The results suggest that the levels of gangliosides and glycogen are affected dose-dependently in various regions of the rat brain and spinal cord.

Animals↗
PubMed1988

Jaccoud's arthropathy--diagnostic and therapeutic implications.

A case of isolated chronic severe aortic regurgitation with Jaccoud's arthropathy involving the foot is presented. The interesting feature of the case is the absence of history of acute rheumatic arthritis at any stage of the illness. The diagnostic and possible therapeutic significance of this otherwise uncommon and benign condition are discussed.

Adult↗
PubMed1988

Comparative bioavailability and in vitro characterization of two brands of diclofenac sodium enteric-coated tablets.

A bioavailability study and an in vitro characterization were conducted on two brands of diclofenac sodium enteric-coated tablets marketed in Jordan. The two brands were found similar in weight variation and content uniformity and both met the BP requirements of disintegration for enteric-coated tablets. The in vitro dissolution, according to the USP XXI method, revealed that brand B had significantly faster dissolution (99% of the drug dissolved in 1 h). The bioavailability was carried out on eight healthy male volunteers who received a single dose (2 x 50 mg) of each product in a crossover design. Blood samples were obtained over a 10 h interval and drug serum concentrations were determined using a sensitive HPLC assay. The two brands did not significantly differ with respect to peak serum concentration (4.4 and 4.5 micrograms.ml-1 for A and B, respectively) or to the lag time between dosing and the appearance of the drug in serum (1.06 and 0.88 h for A and B, respectively). Further, the two brands were not found significantly different with respect to the extent of absorption as indicated by the area under serum concentration-time curve (6.31 and 5.91 micrograms.h.ml-1 for A and B, respectively). Brand B, however, exhibited a significantly earlier time to attain peak serum concentration (1.2 h) compared to brand A (2.4 h). The difference in the tmax values is consistent with the in vitro dissolution pattern for the two brands.

Adult↗
PubMed1987

Relation between transport maxima and inhibition of organic cation excretion in the chicken kidney.

The ability of several organic cations to inhibit differentially the renal excretion of two prototypical organic cations, tetraethylammonium (TEA) and N1-methylnicotinamide (NMN), was investigated using the Sperber technique in chickens. TEA and NMN excretion were inhibited by the following organic cations in order of decreasing potency: quinine, TEA and NMN. The respective competitive potency of these substances was related inversely to their maximum tubular transport rates (Tm). Regardless of inhibitor used (quinine, TEA or NMN), NMN excretion was always inhibited more easily than TEA excretion. In addition, TEA excretion was suppressed more easily than cimetidine excretion by the competitive inhibitor quinine. The Tm of cimetidine was determined to be less than the Tm of TEA, which in turn is less than that of NMN. These results indicate that the Tm of an organic cation is related inversely to its inhibitory potency and related directly to its susceptibility to inhibition, reflecting different affinities of organic cations for the same carrier-mediated transport system.

Animals↗
PubMed1986

Sulphinpyrazone and the platelet serotoninergic mechanism in ischaemic heart disease.

A double blind study in 25 patients with ischaemic heart disease and 20 matched healthy controls examined the effect of sulphinpyrazone on the uptake of serotonin by platelets and the basal concentrations of serotonin in platelets. Uptake was measured using tritium labelled serotonin and basal concentrations estimated spectrophotofluorometrically. Serotonin uptake was significantly increased both in the patients with chronic stable angina of effort and in those with a history of myocardial infarction six months or more previously. Sulphinpyrazone reduced serotonin uptake from 94.25 (SE 8.65) to 57.86 (5.37) cpm/10(8) platelets after 24 weeks of treatment in the group with stable angina and from 137.45 (16.26) to 68.08 (8.38) cpm/10(8) platelets in the myocardial infarction group. Raised basal concentrations in the two groups were also reduced by sulphinpyrazone. Placebo had no effect on serotonin uptake or basal concentrations in either group of patients. The ability of sulphinpyrazone to inhibit uptake and reduce basal concentrations of serotonin in patients with ischaemic heart disease may be yet another mechanism through which this drug exerts its beneficial antiplatelet effect.

Adult↗
PubMed1986

Isolation and estimation of gangliosides in discrete regions of the forebrain: effects of estrogen on regional lipid profiles.

The main aim of the present study was to evaluate the neurochemical changes in the levels of gangliosides, total lipids, phospholipids, cholesterol, esterified fatty acids and triglyceride of the hypothalamus, hippocampus, amygdaloid nucleus, midline nuclei of thalamus, gyrus cinguli and olfactory bulbs following the intramuscular administration of ethinylestradiol (100 mcg) to each female rabbit daily for 30 days. Remarkable increment in the concentration of gangliosides was discernible in hippocampus, amygdaloid nucleus and olfactory bulbs. Interestingly, these levels showed significant decrement in the hypothalamus. The contents of total lipids, triglyceride and esterified fatty acids exhibited significant decrease in the hypothalamus. On the other hand, these levels showed a remarkable increment in olfactory bulbs with a significant elevation in the levels of phospholipids. The concentration of phospholipids was, however, markedly depleted in amygdaloid nucleus. The contents of esterified fatty acids exhibited decrement in hippocampus but the midline nuclei of thalamus showed increment. A significant elevation was also discernible in the levels of triglyceride in gyrus cinguli. The results suggest that the lipid contents are affected differentially in the various parts of the brain.

Animals↗
PubMed1986

Organophosphate dichlorvos induced dose-related differential alterations in lipid levels and lipid peroxidation in various regions of the fish brain and spinal cord.

The effect of dichlorvos (DDVP) (0-0, dimethyl 2:2-dichlorovinyl phosphate), on various lipid fractions and lipid peroxidation in the discrete areas of the brain and spinal cord were studied in the fresh water teleost (Heteropneustes fossilis). Fishes were exposed to three different doses (3.0, 6.0 and 9.0 ppm) of DDVP daily for 7 days. Dose-related increase in the levels of total lipids, cholesterol and esterified fatty acids was detected in the fore brain, optic lobes, cerebellum, medulla oblongata and spinal cord. However, phospholipids were significantly decreased in the aforementioned regions of the central nervous system. The rate of lipid peroxidation was significantly increased in all the regions of the CNS.

Animals↗