Small-sized neurons of trigeminal ganglia express multiple voltage-sensitive calcium channels: A qualitative immunohistochemical study.

The cell bodies of pseudounipolar neurons of the trigeminal ganglia have been presumed to play a supportive role to neurites, which transmit various sensations like pain from the periphery to the brain stem. However, several studies have recently shown that these neuronal cell bodies could modulate the afferent stimuli by up-regulating various ion channels and also by increasing the synthesis of neuropeptides like calcitonin gene-related peptide (CGRP). Since voltage-sensitive calcium ion channels (VSCCs) determine neuropeptides/ neurotransmitters released by neurons, the aim of the present study was to localize the various VSCCs (N-, P/Q-, L-, T- and R-types) in the trigeminal ganglia neurons by immunohistochemistry. The results showed that all the VSCCs are expressed by the cell bodies of neurons though the small-sized neurons showed higher expression of these channels. The small-sized neurons were identified by immunohistochemical localization of CGRP, the most common neuropeptide for pain transmission in the trigeminal ganglia neurons. Some of these channels (N, P/Q and T types) were also expressed on the cell surface though previous electrophysiological studies have shown the expression of all the channels on the cell surface. It is suggested that the cell bodies could play a more active role than hereto ascribed to these, in the modulation of sensory stimuli.

HLA class I profile in Asian Indian patients with pulmonary tuberculosis.

HLA class I antigen profile was studied in 153 unrelated patients with pulmonary tuberculosis (PTB), 40 family contacts and 289 healthy individuals by the NIH microlymphocytotoxicity test to find out the role of HLA-A, -B, -C alleles in influencing susceptibility to PTB and its various clinical groups. HLA-A2 was found to be significantly increased in the total patient group as compared to controls (38.6% vs 26.3%, p < 0.01, RR = 1.76). The increase of HLA-A2 was more pronounced in the sputum negative patients (59.4%, pc < 0.001, RR = 4.1) suggesting its possible role in the mediation of CD8+ suppressor T cell activity against Mycobacterium tuberculosis, resulting in the development of limited disease in these patients. Further, HLA-B18 was found to be decreased in patients as compared to controls (2.6% vs 7.3%, p < 0.05, RR = 0.34). None of the class I antigens was associated with the dynamics of chemotherapy or disease severity as assessed by the extent of lung involvement on chest X-ray examination.