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Biomedical subjects

I Constable

Publications and source records attributed to I Constable.

9 recordsLinked to original sources
PubMed1992

Changes in retinal pigment epithelial cell autofluorescence and protein expression associated with phagocytosis of rod outer segments in vitro.

The accumulation of autofluorescent lipofuscin was quantified in cultured human retinal pigment epithelial (RPE) cells phagocytosing bovine rod outer segments (BROS) and the expression of proteins in these cells was investigated. Results showed a steady increase in autofluorescence of RPE cells over a 4-week period as measured by fluorophotometric flow cytometry. A significantly greater increase in autofluorescence was found in the cultured RPE cells from a 7-year-old donor compared with those from a 47-year-old donor. Within both groups the BROS-challenged cells had significantly higher fluorescence readings than the control cells which were not challenged. Autoradiography of 35S-labelled proteins separated by polyacrylamide gel electrophoresis (PAGE) revealed a small distinct band at 102 kDa in BROS-challenged RPE cells of both bovine and human origin that did not appear in control or microsphere-phagocytosing RPE cells. The intensity of the signal was unrelated to the duration of the challenge period.

Aging↗
PubMed1992

Induced chorioretinal venous anastomosis in experimental retinal branch vein occlusion.

Iatrogenic retinal vein to choroidal vein anastomoses were created using laser photocoagulation in six of seven dog eyes in which a partial branch retinal vein occlusion had previously been created photochemically. A similar attempt to create an anastomosis was made in six control eyes in which no branch vein occlusion was present. In the eyes in which a branch retinal vein had been created, a venous chorioretinal anastomosis appeared to be present by 3 to 6 weeks. In three control eyes similar venous anastomosis was created; however this took 6 to 8 weeks to develop and was of much smaller calibre than the one that developed in the presence of a partial branch retinal vein occlusion. No adverse complications were noted in the period of the study (3 months). This study demonstrates that chorioretinal venous anastomoses can be created and may be of use in the treatment of partial retinal vein occlusions that show signs of progression.

Anastomosis, Surgical↗
PubMed1992

HLA DQA tissue typing of cadaveric eye bank donor material with polymerase chain reaction.

It has been suggested that the provision of HLA matched tissue for corneal transplantation would be beneficial for graft survival especially in high risk patients. In this study we report the application of a polymerase chain reaction (PCR) based tissue typing procedure to type cadaveric donor material. Using beta-globin gene amplification as a test system we found that cornea, corneal rim, conjunctiva, sclera, rectus muscle, optic nerve and neural retina were all suitable for PCR amplification but DNA extracted from pigment epithelial cells and from the iris could not be amplified. HLA DQA typing results of 9 samples identified 5 alleles and 7 genotypes. In two cases the antigens detected by serology reflected the alleles detected by PCR. In a third case in which the class II serological typing was inconclusive we detected two DQA alleles by PCR. These alleles were consistent with those which would be predicted to be present on the basis of known linkage disequilibrium between HLA-Cw, B, DR and DQ. In this study we have shown that PCR based tissue typing is more sensitive and gives more detailed typing results than serology and would be suitable to type cadaveric donor material on a routine basis.

Alleles↗