Biomedical subjects

S M Hasany

Publications and source records attributed to S M Hasany.

8 recordsLinked to original sources

PubMed1992

Toxicity and pharmacokinetics of intravitreally injected ciprofloxacin in rabbit eyes.

To assess the toxicity of intraocular injection of ciprofloxacin, 22 New Zealand white rabbits received midvitreal injections of 100, 200, 400, 800 or 3200 micrograms of ciprofloxacin in 0.1 mL of distilled water (39 eyes) or 0.1 mL of distilled water only (5 eyes). The ocular pharmacokinetics of intravitreally injected ciprofloxacin was determined by aqueous humour and vitreous sampling 1, 2, 4, 8, 12, 18 or 24 hours after midvitreal injection of 100 micrograms of the drug in one eye each of 25 New Zealand white rabbits. The samples were analysed by means of a disc diffusion bioassay. No ocular damage was noted on ophthalmoscopy at any of the concentrations tested. Histologic study showed mild, transient vacuolation of the nerve-fibre layer in all eyes, including the control eyes, 2 hours after injection; at 24 hours no vacuolation was evident except at concentrations of 800 and 3200 micrograms, at which plexiform layer damage was evident. Peak aqueous and vitreous levels of ciprofloxacin were obtained at 1 hour (0.59 and 27.26 micrograms/mL respectively); the vitreous level fell to below 1.0 micrograms/mL 12 hours after injection. We conclude that intravitreally injected ciprofloxacin may be a safe and useful antibiotic in the treatment of aminoglycoside-resistant bacterial endophthalmitis.

Animals↗

PubMed1979

Glucose oxidation in fresh guinea pig cornea.

The rate of glucose oxidation of fresh corneas of guinea pigs at different ages has been determined. Full-thickness corneal discs, 4 mm in diameter, were incubated in radioactive glucose solution. The quantity of the released CO2 was expressed in terms of the corneal discs, their dry weights, and DNA and protein contents. The rate of glucose metabolized to CO2 per hour was about 300 pmol/microgram DNA for guinea pigs weighing approximately 800 g. Glucose oxidation decreased as the age of the animals increased. Our results compared well with those obtained in other species. We therefore feel that the guinea pig should be a suitable model for research on the metabolism of corneas.

Animals↗

PubMed1979

A corneal model for studying the interaction between the endothelium and sensitized lymphocytes.

We wished to develop a simple model for morphological studies on the interaction between the corneal endothelium and specifically sensitized lymphocytes. Rabbits were transplanted with orthotopic allogeneic skin or corneal grafts. After the onset of the transplantation reaction, lymphoid cells from the recipient's spleen or preauricular lymph nodes were harvested and placed on the endothelial surfaces of the donor and recipient corneas which were incubated in tissue culture medium at 37 degree C for 4 hours before being examined by vital staining or scanning electron microscopy. Compared to the recipient, the donor endothelium contained more lymphoid cell aggregates and more corneal cells were damaged. The in vitro model seemed suitable for studying the cytotoxic behaviour of sensitized lymphocytes confronting the corneal endothelium.

Animals↗

PubMed1979

Does the number of cells in the cornea decrease with age? A biochemical study.

We used biochemical techniques to investigate whether the cornea becomes more acellular with age. Guinea pigs of different body weights (age) were killed. From each cornea, a central full-thickness button (4 mm in diameter) was punched out. The DNA content of the corneal buttons was determined. Using spleen cells, the DNA content per diploid cell of guinea pig was also estimated. It was found that as the body weights of the animals increased, the amount of DNA per corneal disc decreased. This indicated that as the animal grows older the total cellular content of the cornea is reduced.

Aging↗

PubMed1979

Biochemical analysis of the cornea stored in steroid medium.

We wished to measure changes in the tissue mass and the deoxyribonucleic acid and protein content of guinea pig corneas stored for up to 21 days in tissue culture medium with or without 1 microM hydrocortisone. Full-thickness discs 4 mm in diameter were cut from the corneas for measurement of the three variables. Whether the disc came from a steroid-treated cornea or not, and whether it came from a fresh cornea, hydrocortisone did not appear to have any adverse effect on the features studied.

Animals↗

PubMed1978

Can steroid reduce endothelial damage in stored corneas? Effect on cell viability and ultrastructure.

We studied the effect of steroid on the viability and integrity of the endothelium of variously stored corneas of different species of animals and man. Paired corneas of rodents and humans were used,--one cornea (experimental) being treated with steroid and the other (control) not. Rat and guinea pig corneas were kept at 37 degrees C for one hour in phosphate buffered saline with or without hydrocortisone 21-sodium succinate (10-6M). Human corneas were kept at 4 degrees C for 4 days in M-K medium with or without hydrocortisone 21-sodium succinate (10-6M). The viability of the endothelia (rat and guinea pig) was tested with para Nitro Blue Tetrazolium and trypan blue dye exclusion tests. The ultrastructural changes in the control and experimental endothelial (guinea pig and human) were examined by scanning electron microscopy. Viable cells P less than 0.001) were more numerous and ultrastructural alteration less in the endothelia of the steroid treated corneas compared to the controls.

Animals↗

PubMed1977

The prevention of autolysis in stored corneas by lysosome stabilization. A histochemical study.

We wished to determine if dexamethasome, acting as a lysosome stabilizer, could reduce the release and activation of the lysosomal acid hydrolases, and thus retard autolysis of stored corneas. One cornea (experimental) of a rabbit was soaked in a 2 per cent steroid solution and the other cornea (control) in physiological saline for 3 hours at 23 degrees C. The experimental and control corneas were then processed histochemically to show the localization of the lysosomal marker enzymes beta-glucuronidase and acid phosphatase. Compared to the controls the steroid treated corneas showed reduced enzyme activity suggesting that autolysis during storage had been retarded.

Acid Phosphatase↗

PubMed1975

Histochemical localization of hydrolytic enzymes during corneal graft reaction.

We studied hydrolytic enzymes in the graft bed during the corneal graft reaction. Two enzymes, beta-glucuronidase and acid phosphatase, were used as the markers of lysosomal hydrolytic enzymes. These were traced histochemically at various times before and after the onset of the graft reaction in a corneal xenograft model. Results showed a relationship between the degree of graft opacity, cellular infiltration and enzyme localization. It appeared that during the early stages of graft reaction, the granulocytes, and during the late stages, the agranulocytes were the main source of the enzymes.

Acid Phosphatase↗