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Biomedical subjects

A A Ismail

Publications and source records attributed to A A Ismail.

At least 109 records · Page 6Linked to original sources
PubMed1981

Evaluation of marketed and formulated furosemide tablets.

Five commercial brands of furosemide tablets were evaluated using the official and non-official tests of U.S.P. XIX. These tests include: uniformity of weight, hardness, friability and disintegration time. The results obtained showed that most of these brands failed to attain the U.S.P. requirements. The inclusion of different surface active agents in some of the new suggested formulae was proposed for improving the poor properties of such commercial furosemide tablets. In addition to the above quality control tests, dissolution rate studies of the new formulated tablets were carried out. The addition of 11.4% dioctyl sodium sulphosuccinate increased the dissolution rate up to 48.5% after 60 min. On the other hand, the same concentration of sodium lauryl sulphate caused complete tablet dissolution within 45 min. The effect of a higher concentration of sodium lauryl sulphate on the dissolution rate of furosemide has also been examined.

Furosemide↗
PubMed1980

Effect of Triiodothyronine on Bronchial Asthma. III.

In two previous communications we demonstrated that triiodothyronine (T3) improved cases of chronic bronchial asthma (CBA). In this communication we administered T3 in a dose of 40 microgram/day for a period of sixty days to twelve cases of CBA aged less than 38 years who had had the condition for more than 5 years and were not on steroids or chromoglycate. All were outpatients. Respiratory functions including vital capacity and timed expiratory volume were tested before and after the period of drug administration. Patients were also advised to record the number of attacks and amount of bronchodilators used. All patients had their % T3 uptake and thyroxine (T4) serum level examined before the experiment. Ten normal persons of matching ages and sexes had their blood examined for % T3 uptake and levels as control. The results have shown that the patients had normal % T3 uptake and T4 levels in blood. Their vital capacity increased by an average of 4.27%, their first-second expiratory volume by 17.58% (P less than 0.0025), their second-second expiratory volume by 13.74% (P less than 0.0025%), and their maximal ventilatory volume by 12.95% (P less than 0.0025). Five cases had an increase of over 20% and 5 cases had practically no increase or a mild reduction. Subjective improvement and reduction in amount of bronchodilators used correlated well with the improvement in ventilation. It is argued that T3 acts through having the capacity to increase cAMP, a main messenger in bronchodilation that is known to be deficient in asthmatics.

Adult↗
PubMed1979

Ultrastructure of intermediate lobe of the pituitary and melanocyte-stimulating hormone secretion in oestrogen-induced kidney tumours in male hamsters.

One group of male Syrian hamsters was killed after various periods of diethylstilboestrol (DES) treatment, ranging from 6 to 36 weeks. All developed renal tumours by 24 weeks. DES also induced hyperplastic and neoplastic changes in the pars intermedia of the pituitary with proliferation of MSH-secreting cells and elevated serum MSH concentration. Another group of male Syrian hamsters was given DES for 36 weeks followed by cessation of hormone treatment. The animals were killed at various intervals from 12 to 36 weeks after DES withdrawal. In these animals the DES-induced renal tumours underwent regression whilst the pituitary changes persisted until the termination of the experiment. The findings suggested that the hormone MSH may be implicated in renal carcinogenesis but plays no role in the maintenance of the established tumours.

Animals↗
PubMed1978

Studies of estrogen induced renal tumours in male Syrian hamsters. I. Cytochemical studies of lysosomal enzymes acid phosphatase and beta-glucuronidase.

The localization and concentration of lysosomal enzymes acid phosphatase and beta-glucuronidase in kidney cells of Syrian hamsters after DES administration were studied. A positive cytoplasmic reaction was demonstrated for both enzymes. Increased activity of these enzymes were observed in renal tumour in contrast to normal homologous cells. These results can be explained on the basis that lysosomal enzymes were synthesized in tumour cells at a higher rate or it may be due to the invasion of tumour tissue by hydrolase rich microphages.

Acid Phosphatase↗
PubMed1978

Purification and properties of rennin-like enzyme from Aspergillus ochraceus.

An active milk-clotting enzyme was purified some 40-fold from culture supernatant of Aspergillus ochraceus. The purification steps included ammonium sulfate precipitation, G-100 Sephadex gel filtration, and ion exchange chromatography, using DEAE Cellulose column. The enzyme exhibited milk-clotting activity and proteolytic behaviour, an optimum at pH 6.0 and in the range of 7--8.5, respectively. The purified enzyme was actively proteolytic against casein, haemoglobin, and bovine serum albumin at pH 8. The milk-clotting activity was greatly enhanced by manganous ions and by increasing concentrations of calcium chloride. Copper, zinc, and ammonium ions were potent inhibitors of the milk-curdling activity of the purified enzyme. Significant inhibition was also noted with sodium chloride at concentrations of 3% or more. Under the specified reaction condition, maximum rate of proteolysis against casein was obtained at 0.4% substrate concentration, whereas the milk-clotting time was linear proportional to dry skim milk concentration in the range of 8 to 24%. The results are discussed in comparison with other microbial milk-clotting enzymes, and limitations of applicability are also presented.

Animals↗
PubMed1978

The "Southmead System," a simple, fully-automated, continuous-flow system for immunoassays [Appendix: application to serum thyroxine radioimmunoassay].

A simple, fully-automated, continuous-flow system suitable for radioimmunoassay, enzyme immunoassay, and fluoro-immunoassay is described. The system is versatile, inexpensive, and requires only equipment and skills that already are available in most clinical chemistry laboratories. In this system, the antibody is covalently linked to solid-phase, porous particles of agarose (Sepharose, size 40-70 micrometer in the dry form). After sampling and mixing the assay reactants, the assay "cocktail" containing the solid-phase-bound antigen and the unbound fraction is directed to the separation block. Separation is achieved by use of a highly porous membrane (pore size, about 10 micrometer) and by controlling the volume of inflow and outflow a fixed and precise amount of fluid is filtered through the membrane containing only the free (unbound fraction), which can then be quantitated. The percentage of unbound fraction misclassified is negligible (less than 1.0%). Application of these principles to the assay of serum thyroxine is described in an appendix.

Autoanalysis↗
PubMed1978

Effect of oestrogen on the pituitary gland of male Syrian hamsters. I. Electron microscope studies of pars intermedia.

The ultrastructure of the pars intermedia of normal and oestrogen-treated male Syrian hamsters is described. 3 types of cell were observed in normal gland, namely, 2 types of "light" cell and a "dark" cell. Light cells were regular in shape with round or oval nuclei and could be divided into type 1 and 2 by the size of their granules 200 to 250 nm in type 1 and 100 to 150 nm in type 2. Dark cells were fewer in number, irregular in outline with highly-indented chromatin-rich nuclei and occasional secretory granules in the Golgi area. Treatment for 6 weeks with diethylstibestrol (DES) 0.6 mg in 0.2 ml distilled water subcutaneously 3 times per week failed to induce recognisable change in the pars intermedia although after 12 weeks treatment cytoplasmic changes were observed. From that time until the experiment ended after 30 weeks of treatment progressive changes indicative of enhanced synthesis of hormone were present, greater cytoplasmic volume, hypertrophy of the Golgi apparatus, marked development of endoplasmic reticulum and ribosomes, increased numbers of secretory granules and the presence of granules within granules.

Animals↗
PubMed1977

Effect of triiodothyronine on bronchial asthma. II.

Triiodothyronine (T3) administration to patients suffering from chronic bronchial asthma or patients suffering from nasopharyngeal allergy was reported to ameliorate the attacks. Twelve patients aged less than 35 years suffering from chronic bronchial asthma for more than 5 years, who were maintained on usual anti-asthmatic drugs with the exception of steroids and chromoglycate and who were not the subject of repeated attacks of bronchitis were chosen for the study. Each patient was given T3 orally as 40 micron/day divided into two doses, for a period of 60 days. The drug increased the peak flow in all cases. The increase averaged 24.6% +/- 8.48 (P less than 0.001). Three cases reported marked improvement and four were able to reduce the dose of anti-asthmatic drugs. There was no significant change in the pulse rate, ECG, body weight, blood pressure, or appetite. One patient complained of insomnia and another of increased anxiety. It is possible that T3 exerts its beneficial effect through correcting the level of C-AMP, which is known to be low in asthmatics, through improvement of body mechanism for antibody formation, or through other unidentified mechanisms.

Adult↗
PubMed1977

Cytochemical studies of respiratory enzymes in carcinoma of the cervix uteri after irradiation by radium and cobalt 60.

Enzymological studies of succinic dehydrogenase and cytochrome oxidase were made on human squamous cell carcinoma of the cervix uteri before, during and after radiation therapy by radium and 60CO. The enzymatic activities of the two enzymes were higher in cells of stage III than in the corresponding cells of stage II. In addition, after treatment, no enzymatic activity could be detected. These changes may be explained on the basis of mitochondrial damage as a result of radiation effect.

Biopsy↗
PubMed1976

Ethyl cellulose as a potential sustained release coating for oral pharmaceuticals.

This current study was motivated, and designed in an attempt to determine the possible application of the inert, pH-insensitive, ethyl cellulose polymer as a potential sustained-release coating for oral pharmaceuticals. Coating was effected using two relatively recent techniques, namely microencapsulation by phase separation coacervation, induced by temperature change, and drug entrapment by flocculation, induced by nonsolbent addition. Chloramphenicol was used as a model drug. Results of this study revealed the fact that ethyl cellulose proved to be a potential sustained-release coating for oral dosage forms. Moreover, the effect of the coating/core ratio was exhibited both qualitatively and quantitatively. This finding could help in the design of programmed or timed-release drugs. Accordingly, this study could be considered a successful attempt towards the utlization of ethyl cellulose in of the design of sustained-release oral pharmaceuticals.

Capsules↗
PubMed1976

Polysalt flocculates as a physicochemical approach in the development of controlled-release oral pharmaceuticals.

In the field of pharmaceutical formulation, polysalt flocculates have received relatively little attention in the literature. Accordingly this investigation could be considered an approach towards the development of oral controlled release dosage forms by polysalt flocculates. The polymer selected for this study was sodium carboxymethylcellulose. This was based on the fact that it forms an insoluble complex with aluminium sulphate, which could be of value in controlling the liberation of the entrapped drug. Drug entrapment was effected by polymeric flocculation, induced by the addition of a physiologically inert electrolyte. Results of this study indicated that this approach provided a physicochemical method for controlling drug release from oral pharmaceuticals, that could be claimed to replace the earlier empirical mechanical methods.

Administration, Oral↗
PubMed1976

Physiology and characterization of a fungal milk-clotting enzyme from Aspergillus flavus.

Aspergillus flavus produced extracellularly an active rennin-like enzyme when grown aerobically in whey media. The enzyme was detected at early stages of growth reaching a maximum after three to four days at 25 degrees. The activity was destroyed by heating to temperatures higher than 50 degrees, whereas the presence of skim milk during heating preserved the enzyme activity, at least, up to 70 degrees. Calcium chloride significantly stimulated the milk-clotting activity up to 1% final concentration. The clotting time was inversely proportional to protein concentration in the range 0.2-0.6 mg/ml and the enzyme exhibited marked stability when stored at 37 degrees at pH 6.

Animals↗