Anatomical studies on the optic chiasma in the Indian buffalo (Bubalus bubalis).

The optic chiasma of the buffalo was a transversely oval body, averaging 9.0 +/- 0.89 X 12.3 +/- 0.48 X 5.0 +/- 0.48 mm. Its shape was like a letter "X". This was located 2--3 mm cranial to the pituitary. Following unilateral enucleation, the degenerating myelinated fibres were noted throughout the optic chiasma, and in both the optic tracts. The degeneration in the contralateral optic tract was more dense. By enumerating the degenerating fibres in the remnant optic nerve, in the ipsilateral and contralateral optic tracts it was noted that 57.34% of the optic nerve fibres crossed over and only 12.29% of the fibres remained uncrossed.

Anatomical studies on the optic tract (tractus opticus) of the Indian buffalo (Bubalus bubalis).

The optic tract of the buffalo was found to begin from the posterolateral angle of the chiasma, from where it extended laterally for about 8 mm. Each tract was round in its initial portion, but was flattened subsequently. In its course to the corpus geniculatum laterale (CGL), it swept round the homolateral cerebral peduncle. The tract fibres entered the CGL chiefly on its ventrolateral aspect. The optic fibres appeared to enter the CGL as individual fibres. The fibres in the optic tract were mostly myelinated. There were 253823 +/- 27534-254800 +/- 29232 myelinated fibres in it. There was no fascicular arrangement of these fibres. The calibre of the myelinated fibres in the optic tract varied from 1-12 microns. A fibre diameter analysis revealed an unimodal distribution of these fibres with a peak at 2 microns. Thinner fibres predominated in the peripheral portion of the optic tract. In the central portion, fibres of larger diameter were seen in greater numbers.

Anatomical studies on the corpus geniculatum laterale in the Indian buffalo (Bubalus bubalis).

The CGL of the buffalo was convex, swung in a semicircle around the thalamus and was covered by the fibres of the optic tract. It was distinctly laminated, possessing a maximum number of 5 cellular laminae. The individual cell layers were separated from each other by clearly defined myelin interlayers. Laminae I and II were magnocellular and Laminae III, IV and V were parvicellular. No significant difference was found in the diameters of the neurons of the corresponding laminae of the two sides of CGL of the same specimen. From degeneration studies it was observed that the retina projected contralaterally to laminae I, III and V and ipsilaterally the input was to laminae II and IV with little or no overlap.

Contact Hypersensitivity to Topical Antimicrobial and Antifungal Agents.

To find out the incidence of hypersensitivity to antimicrobial drugs patch tests with various commercially available antimicrobial agents were carried out in 112 patients suspected of contact sensitivity to these substances. Eighty eight patients showed positive reaction to one or more drugs. H incidence of contact sensitivity was observed with neomycin (48%), nitrofurazone (460/o) and bromsalicyl chloranilide (45%), while gentian violet gentamicin and povidone iodine were found to be the least sensitizers (5%, 6% and 70/o - respectively). Multiple hypersensitivity (four or more drugs) was observed in 25 patients and a large number of them had ulcers at the time of study or in the past.