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Biomedical subjects

P K Basu

Publications and source records attributed to P K Basu.

At least 109 records · Page 6Linked to original sources
PubMed1979

Anticomplementary activity of cornea, vitreous and chorioretina in rabbits.

We wished to determine if inhibitors of the complement system are present in different rabbit ocular tissues. Soluble extracts of cornea, vitreous humor and chorioretina in different dilutions were incubated with normal human serum (as source of complement). The ability of the latter to lyse sheep erythrocytes sensitized with antisheep rabbit hemolysin was assessed. The cornea did not show any inhibition of complement. The vitreous humor exhibited very low inhibitory activity. The extracts of the uveo-retinal tissue contained heat-labile and heat-stable factors capable of cleaving C3 and factor B.

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

An analysis of corneal transplantation: I--graft clarity.

A retrospective review has been undertaken of the clarity results of 378 keratoplasties performed by 6 Toronto corneal surgeons between January 1970 and December 1974. Lamellar keratoplasties were included in the data related to herpes simplex only. In herpes simplex penetrating grafts gave better vision than lamellar grafts. The following factors were statistically important with respect to graft clarity: age of recipient, type of corneal disease, peroperative corneal vessels, first or subsequent graft, pre- and/or postoperative glaucoma, postoperative anterior synechiae, combined procedure, vitreous loss, previous cataract surgery, and follow-up time. The following factors were statistically unimportant with respect to graft clarity: donor age, time from death to enucleation (median 2.8 hours), time from enucleation to use (median 24 hours), sex of donor and recipient, interrupted or running suture, use of microscope, penetrating or lamellar graft in herpes simplex, postoperative astigmatism, and division of postoperative anterior synechiae. Silk (compared with nylon), larger grafts and combined procedures all increased the incidence of graft rejection. Repeat grafts were associated with more preoperative corneal vascularization.

Adolescent↗
PubMed1979

An analysis of corneal transplantation: II--postoperative astigmatism.

An analysis of 153 penetrating keratoplasties was undertaken. The same surgical technique was used in all cases. Three factors had a statistically significant effect on postoperative astigmatism, as measured by keratometry. (1) Astigmatism decreased with increasing follow-up time (P less than 0.05). (2) Vitreous loss at the time of the keratoplasty increased the amount of postoperative astigmatism (P less than 0.05). (3) Females had more postoperative astigmatism than males (P less than 0.05), but this was probably related to a tendency for females to have a greater incidence of postoperative anterior synechiae (P just greater than 0.05), and the fact that all 6 cases of vitreous loss were in females. There was an almost significant trend toward postoperative anterior synechiae being associated with increased astigmatism (P just greater than 0.05), and there was also a trend toward the division of these synechiae reducing the amount of astigmatism. Fifteen of the 153 penetrating grafts were done in cases of herpes simplex. These were compared with 11 lamellar grafts done for herpes simplex, and there was a statistically insignificant trend toward more postoperative astigmatism in penetrating grafts.

Astigmatism↗
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

Does a barbiturate drug given in lethal dose enter the cornea?

We wished to see whether sodium phenobarbital (one of the commonest drugs used to commit suicide) given in a lethal dose would enter the cornea. Guinea pigs and rabbits were killed with an overdose of the drug. Using gas chromatography we were able to detect the drug not only in the vascular ocular tissues and the intraocular fluids but also in the avascular tissues such as the cornea.

Animals↗
PubMed1979

The anticomplementary activity of the rabbit lens.

We wished to determine if inhibitors of the complement system are present in the normal rabbit lens. Soluble less extract in various dilutions was incubated with normal human serum (as source of complement). The residual hemolytic activity was measured using sheep erythrocytes sensitized with antisheep rabbit hemolysin. The lens extract was found to contain two heat stable anticomplementary factors of different molecular weights capable of cleaving C2 and C4. Gel filtration showed that one of these factors was located in the alpha-crystalline region. It is suggested that the anticomplementary factors in the lens may be related to a natural mechanism for the modulation of complement mediated lens injury.

Adult↗
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

Ocular toxoplasmosis in three consecutive siblings.

Ocular toxoplasmosis in consecutive siblings is rare. We report positive ocular and serologic findings in three consecutive teenaged siblings. Results of immunologic studies that were performed on members of the family failed to reveal deficiencies.

Adolescent↗
PubMed1978

Effects of cigarette smoking on intraocular pressure and vision.

In a survey of 426 patients of Toronto ophthalmologists the correlations of reported smoking habits with (1) intraocular pressure and (2) visual acuity were examined. Average tonometer readings were closely similar in smokers, ex-smokers, and non-smokers, and multiple regression analysis showed similar age coefficients for the 3 categories. However, in women (but not in men) there was also a significant coefficient related to total cigarette exposure (puff-pack-years). It is suggested that this was due to recent smoking rather than a permanent effect on tonometer pressures, pointing the need to standardise this aspect of ocular pressure measurements. Visual acuity showed similar age coefficients in smokers, ex-smokers, and non-smokers, with no independent effect of exposure to cigarette smoke.

Adult↗
PubMed1978

Blood flow in rabbit eyes after keratectomy and corneal transplantation.

We used radio-labelled microspheres to study the distribution of blood flow in different regions of rabbit eyes with inflamed corneas resulting from trauma or allograft reaction. The blood flow in the cornea, the anterior uvea and the regional lymph nodes draining it was increased, but total flow in the eye did not increase. More blood went to the anterior uvea at the expense of the rest of the eye. Blood flow at the limbus was higher in the inflamed corneas than in the controls.

Animals↗
PubMed1978

Prediction of graft fate from cytopathology of recipient button.

We wished to know whether the fate of human corneal grafts could be predicted from the cytological study of recipient's corneal buttons removed at operation. We counted the number of different inflammatory cells in 168 full-thickness corneal buttons, and related the findings to the operative results retrospectively. If inflammatory cells, particularly polymorphonuclear cells are present in significant numbers in the corneal button the chance of a successful graft is reduced by about 20 per cent (P less than 0.05).

Cornea↗
PubMed1978

Are serum antibody, complement or K-cell dependent cellular cytotoxicity involved in corneal graft rejection?

Having shown that complement independent cellular cytotoxicity (CICC) plays a part in destroying the donor cell we wished to see if serum antibody cytotoxicity (SAC), complement dependent cellular cytotoxicity (CDCC) or K-cell mediated cellular cytotoxicity (KCC) might not also be involved in the rejection of corneal grafts. Rabbits were grafted with allo- and xenogreneic corneas. At various times, lymphoid cells and sera were collected from a recipient and a control animal. The donor's corneal cells and those of the control animal were cultivated in vitro, and then labelled with 51chromium. The recipient and control lymphoid cells and sera and/or complement were mixed with the labelled cells. A 51chromium release assay was done after incubation. The test was negative for SAC, CDCC, and KCC and we feel that they have no major part in the rejection of corneal grafts.

Animals↗
PubMed1978

The predictive value of leucocyte migration inhibition test in human keratoplasty.

We compared the results of penetrating keratoplasty in 18 patients whose preoperative or immediate postoperative leucocyte migration inhibition (LMI) tests were positive (greater than 20% inhibition) with those in 15 patients whose LMI tests were negative. A negative LMI test indicated a greater chance of avoiding graft rejection (P less than 0.005), and of ending up with a clear graft (P less than 0.05).

Cell Migration Inhibition↗