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J E Campion

Publications and source records attributed to J E Campion.

6 recordsLinked to original sources
PubMed1982

Mixed lymphocyte reactivity in cattle.

Mixed lymphocyte reactivity (MLR) in cattle was assessed by measuring the extent of cellular proliferation between allogeneic lymphocytes in an in vitro test system. To test for involvement of the bovine major histocompatibility system (BoLA) the MLR tests were done using full-sibling cattle families which had been generated through the use of embryo transfer systems. The results showed that the responses in the MLR tests were associated with the BoLA antigen sharing status between the individuals being tested. Since the tests, were done using full-sibling combinations, this result suggests genetic linkage between the MLR controlling antigens and the BoLA complex.

Animals↗
PubMed1978

Retinal abnormalities in the Siamese cat.

Ganglion cell density maps of the retinas of Siamese cats show the same major features of ganglion cell distribution as are found in normally pigmented cats, in particular the area centralis and visual streak. In the retinas of the seven Siamese cats investigated, however, the areas centralis was "underdeveloped" when compared with the normally pigmented cat. The peak ganglion cell density was lower and the ganglion cells usually larger than at the area centralis of the normally pigmented cat, and the characteristic blood vessel pattern around the area centralis was less developed. One animal showed a marked blood vessel abnormality, a vessel crossing the area centralis in each retina. In another animal, the distribution of ganglion cells appeared abnormal throughout the retina. Medium-sized, possibly X-type ganglion cells were lacking from all retinal areas, overall cell numbers were low and the distribution of ganglion cells showed a prominent visual streak.

Animals↗
PubMed1978

The nasotemporal division of retina in the Siamese cat.

By sectioning one optic tract in Siamese kittens and allowing sufficient time for the affected ganglion cells to degenerate and disappear, we have obtained maps of the distribution of ipsi- and contralaterally projecting ganglion cells in the retina of the Siamese cat. As previous work predicted, many ganglion cells in the Siamese cat retina project contralaterally which, in the normally pigmented cat, would project ipsilaterally. The transition from the pattern of projection typical of nasal retina (all contralateral) to that typical of temporal retina (most ipsilateral) is much more gradual in the Siamese cat than in the normally pigmented cat, and is centred 1.7-3 mm temporal to the area centralis, instead of at the area centralis. In the Siamese cat only a few ganglion cells at the area centralis project ipsilaterally, as against nearly 50% in the normally pigmented cat. The proportion of ipsi-projecting cells reaches the 50% level 1.7-3.0 mm into temporal retina, and overall the zone of transition may be several millimetres wide, as against about 0.2-0.5 mm in in the normall pigmented cat. Evidence is presented that the degree of the abnormality of nasotemporal division varies between individual Siamese cats and that the abnormality is more severe among large or "giant" cells than among the population as a whole.

Animals↗
PubMed1978

Estimate of the number of myelinated axons in the cat's optic nerve.

The number of myelinated axons in the cat's optic nerve has been estimated from a partial count of sections of the nerve examined by electron microscopy. The average count obtained from four nerves was 128,600 (range 112,800-147,200). This figure is within 10% of a previous estimate of the number of ganglion cells in the cat's retina, but is 33% lower than the only previous estimate of the number of these axons based directly on electron microscopy. Possible sources of the discrepancy are discussed. The functional implications of this total, in the context of earlier work on ganglion cell topography, are also discussed.

Animals↗