Tissue samples were collected at random from cattle (Bos taurus) and buffalo (Bubalus bubalis) from an abattoir of the district of Lahore and were analyzed for the presence of Mycobacterium avium subsp. paratuberculosis and Mycobacterium bovis through acid-fast staining and polymerase chain reaction (PCR). Body condition of animals and diarrhea were recorded. Most of the animals were emaciated. Diarrhea was noticed in 15.6% of buffaloes and 19.2% of cattle. Intestinal pathology was observed in 29% of buffaloes and 32.8% of cattle. Number of mesenteric lymph node (MLN) showing gross lesions was a bit higher (35.6%) in cattle than buffalo (31.2%). Acid-fast staining of tissue scraping smears revealed the presence of acid-fast bacilli (AFB) in 17.4% intestinal and 16.4% MLN tissue samples in buffalo, while in cattle 19.2% intestinal and 17.8% MLN were found positive for AFB. In buffaloes, PCR confirmed 12.8% intestinal and 12.4% MLN positive samples for M. avium subsp. paratuberculosis. However, in cattle, PCR analysis demonstrated 14.2% positive results for M. avium subsp. paratuberculosis in both MLN and intestinal tissue samples. PCR also confirmed M. bovis in 5.8% of cattle and 5% of buffalo MLN and intestinal tissues. PCR positive tissue samples for M. avium subsp. paratuberculosis were from those animals which were emaciated, having diarrhea, and severe gross lesions. AFB were also detected in tissue scraping smears of these animals. It is concluded that infection by various mycobacterium species can be differentiated by PCR, which is not possible by acid-fast staining technique.

Key pointsr Acutely isolated rat magnocellular neurosecretory cells (MNCs) display reversible hypertrophy when exposed to hypertonic saline (325 mosmol kg −1 ) for tens of minutes.r Osmotically evoked hypertrophy is prevented by agents that block Na + channels, TRPV1 channels (which mediate an osmotically evoked depolarization in these cells), L-type Ca 2+ channels, and exocytotic fusion and is associated with an increase in whole-cell capacitance.r Exposure to hypertonic saline activates phospholipase C leading to a decrease in plasma membrane phosphatidylinositol 4,5-bisphosphate.r Inhibition of phospholipase C or protein kinase C prevents osmotically evoked hypertrophy and activation of protein kinase C evokes hypertrophy in the absence of an increase in osmolality.r These results suggest that osmotically evoked hypertrophy is triggered by an increase in MNC action potential firing, leading to Ca 2+ influx, the activation of phospholipase C, an increase in diacylglycerol, and the activation of protein kinase C. AbstractThe magnocellular neurosecretory cells of the hypothalamus (MNCs) synthesize and secrete vasopressin or oxytocin. A stretch-inactivated cation current mediated by TRPV1 channels rapidly transduces increases in external osmolality into a depolarization of the MNCs leading to an increase in action potential firing and thus hormone release. Prolonged increases in external osmolality, however, trigger a reversible structural and functional adaptation that may enable the MNCs to sustain high levels of hormone release. One poorly understood aspect of this adaptation is somatic hypertrophy. We demonstrate that hypertrophy can be evoked in acutely isolated rat MNCs by exposure to hypertonic solutions lasting tens of minutes. Osmotically evoked hypertrophy requires activation of the stretch-inactivated cation channel, action potential firing, and the influx of Ca 2+ . Hypertrophy is prevented by pretreatment with a cell-permeant inhibitor of exocytotic fusion and is associated with an increase in total membrane capacitance. Recovery is disrupted by an inhibitor of dynamin function, suggesting that it requires endocytosis. We also demonstrate that hypertonic solutions cause a decrease in phosphatidylinositol 4,5-bisphosphate in the plasma membranes of MNCs that is prevented by an inhibitor of phospholipase C (PLC). Inhibitors of PLC or protein kinase C (PKC) prevent osmotically evoked hypertrophy, and treatment with a PKC-activating phorbol ester can elicit hypertrophy in the absence of changes in osmolality. These studies suggest that increases in osmolality cause fusion of internal membranes with the plasma membrane of the MNCs and that this process is mediated by activity-dependent activation of PLC and PKC.L. Shah and V. Bansal have contributed equally to this work.