Effect of nitration on protein tyrosine phosphatase and protein phosphatase activity in neuronal cell membranes of newborn piglets

Protein tyrosine phosphatase predominantly determines the status of protein tyrosine kinase-dependent phosphorylation of specific proteins and controls the survival and death of neurons. Previous studies have shown that protein tyrosine phosphatase activity is decreased during hypoxia in cortical membranes of the newborn piglet. We have also shown that nitric oxide (NO) free radicals are generated during hypoxia, and may result in modification of protein tyrosine phosphatase via peroxynitrite-mediated modification. The present study tests the hypothesis that the hypoxia-induced decrease in protein tyrosine phosphatase activity is NO-mediated. To test this hypothesis, in vitro experiments were conducted by measuring protein tyrosine phosphatase activity in the presence of an NO donor, sodium nitroprusside (SNP), or peroxynitrite. Since 3-nitrotyrosine is produced as a consequence of peroxynitrite reactions, we have also examined the effect of 3-nitrotyrosine on protein phophatase activity. Cerebral cortical P(2) membranes were prepared from seven normoxic newborn piglets and each sample was divided into three aliquots: a control group, a SNP group (exposed to 200 microM SNP), and a peroxynitrite group (exposed to 100 microM peroxynitrite). Protein tyrosine phosphatase activity was determined spectrophotometrically in the presence or absence of 2 microM bpV(phen), a highly selective inhibitor of protein tyrosine phosphatase. The protein tyrosine phosphatase activity was 198+/-25 nmol/mg protein/h in the normoxic group, 177+/-30 nmol/mg protein/h in the SNP group (p=NS versus normoxic) and 77+/-20 nmol/mg protein/h in the peroxynitrite group (p<0.001 versus normoxic). The results show that peroxynitrite but not SNP exposure results in decreased protein tyrosine phosphatase activity in vitro. Furthermore 3-nitrotyrosine (100 microm), a product of peroxynitrite, decreased the enzyme activity from 926+/-102 to 200+/-77 (p<0.001). We conclude that protein tyrosine phosphatase regulation is mediated by peroxynitrite. We propose that hypoxia-induced NO production leading to peroxynitrite formation is a potential mechanism of protein tyrosine phosphatase inactivation in vivo. The NO-induced decrease in protein tyrosine phosphatase and protein phosphatase activity, leading to Bcl-2 protein phosphorylation and loss of its antiapoptotic activity may be a NO-mediated mechanism of programmed cell death in the hypoxic brain.     

Comparison of Vitek Yeast Biochemical Card with conventional methods for speciation of Candida

The ability of the Vitek Yeast Biochemical Card to identify yeast isolates was compared with conventional methods. Of the fifty yeast isolates tested same species identification was obtained in thirty-four isolates. The Vitek yeast biochemical card identified 13 isolates which could not be identified by the conventional tests. Though the Vitek Yeast biochemical card gave a good rapid identification the high cost of each test severely limits its routine use in most of the laboratories.     

Immobilisation stress induced analgesia in diabetic rats

Stress is known to produce analgesia. The pain threshold is altered in diabetes. We studied the effect of 1 hr of immobilisation stress on pain threshold in male Wistar rats. The same effect was tested in streptozotocin induced diabetic rats. The pain threshold of tail flick, vocalisation and vocalisation after discharge increased in the control group after the stress procedure. Significant analgesia was also obtained in diabetic rats, for flick and after discharge pain threshold. However the vocalisation threshold was not altered, probably due to the antagonistic action of glucose on opiate receptor at the level of brain stem.     

EFFICACY OF SUCRALFATE IN PREVENTING GASTROINTESTINAL SIDE EFFECTS OF NSAIDs

To find out the efficacy of sucralfate in preventing gastrointestinal side effects of non-steroidal anti-inflammatory drugs (NSAIDs) a prospective, randomised single blind study was conducted from 1989 to 1992. Patients with osteoarthritis, rheumatoid arthritis and other long standing painful conditions, who were expected to receive NSAIDs for over three months, were recruited into the study. All medicines were discontinued for a period of 10–15 days prior to initial endoscopic assessment. NSAID therapy was started and the patients were randomised to receive either placebo (group A) or sucralfate (group B) in addition. Patient were reassessed clinically every week and an endoscopic examination was repeated after 6–8 weeks of follow-up. A total of 176 patients were studied in group A (n=91) and group B (n=85). At the end of 8 weeks gastrointestinal symptoms were present in 30.6% and 26.4% patients of group A and B respectively. Endoscopic assessment showed superficial lesions in 36.5% and 18.7% while endoscopic ulcer in 2.4% and 1.1% patients of groups A and B respectively. Thus in patients receiving chronic NSAID therapy, simultaneous administration of sucralfate reduces the incidence of superficial gastric lesions but has no significant effect on symptoms or ulcer formation.KEY WORDS: Gastropathy, Sucralfate, Nonsteroidal anti-inflammatory drugs     

Neuro-otological profile of Episodic Vertigo

Episodic Vertigo Comprises a large group of patients seen in any neurootology unit. A total of 118 subjects were reviewed who attended the neurootology unit. Vertigo of shorter duration was noted in 78 and of longer duration in 40 cases. 51 cases showed bilateral neurosensory deafness, 15 cases had bilateral and another one case had unilateral conductive loss. Spinovestibular tests were abnormal in all cases of vertigo of short duration but only 29 cases showed abnormal reflex in patients with a long duration of illness. Thermal vestibulometry revealed hyporeflexia in 33 cases, directional preponderance in 30 cases and 4 cases showed hyperreflexia 28 cases had peripheral lesions while 81 cases had central lesions. The acute cases showed significant improvement on follow up except cases with abnormality in thermal vestibulometry . The cases with positional nystagmus showed improvement with head and body balance exercises expect in those who received treatment with vestibulosedative and vestibular suppersive drugs. Hearing loss remained the same except in patients with middle ear disorders.     

Persistent congenital milia with naevus spilus

We are reporting a case of solitary persistent left-sided endoareolar congenital milia in association with no serious malformation or abnormality of any structure except the presence of naevus spilus, on the back of the ipsilateral forearm.     

THE ROLE OF RAPID SLIDE CULTURE IN THE DIAGNOSIS AND MANAGEMENT OF PULMONARY TUBERCULOSIS

Rapid slide culture method using human blood medium was utilized for the primary culture of Mycobacterium tuberculosis and the results obtained were compared with results of smear examination of sputum specimens from fresh cases of pulmonary tuberculosis. Smear and rapid slide culture results of a total of 320 patients were analyzed. Slide culture was positive in 104 cases whereas smears were positive in 90 cases. Early culture confirmation in 7 days coupled with positivity better than smear examination, makes rapid slide culture a better method for diagnosis.KEY WORDS: Mycobacterium tuberculosis, Rapid slide culture, Bacteriological techniques, Colony count microbial