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Biomedical subjects

K Jha

Publications and source records attributed to K Jha.

8 recordsLinked to original sources
PubMed2000

Inhibition of motility of hamster spermatozoa by protein tyrosine kinase inhibitors.

Genistein, tyrphostin and piceatannol, which are specific inhibitors of protein tyrosine kinase, were screened for their effects on the motility of intact and demembranated hamster spermatozoa. Of the three inhibitors only piceatannol inhibited the motility of intact spermatozoa. None of the inhibitors had any inhibitory effect on the reactivation of motility of demembranated hamster spermatozoa. Taken together these results indicated that a protein tyrosine kinase associated with the membrane of hamster spermatozoa was probably involved in sustenance of hamster sperm motility. Therefore in the present study a membrane-associated protein tyrosine kinase was purified from a detergent-soluble extract of plasma membranes of mature hamster spermatozoa. The purification involved cation exchange chromatography on fast protein liquid chromatography (FPLC) followed by affinity chromatography either on an antiphosphotyrosine antibody agarose or poly glu-tyr agarose column. The pure protein tyrosine kinase had an apparent molecular mass of 45 kDa. The enzyme was not inhibited by genistein or herbimycin but was inhibited by piceatannol. This is the first report on the purification of a sperm plasma membrane-associated protein tyrosine kinase, an enzyme which has also been implicated in hamster sperm motility.

Animals↗
PubMed1999

Plasma membrane-associated protein tyrosine phosphatase activity in hamster spermatozoa.

Plasma membranes of caput and cauda epididymal spermatozoa of hamster exhibited protein phosphatase activity. This membrane-associated protein phosphatase was identified as a protein tyrosine phosphatase based on its ability to hydrolyse a substrate specific for PTPase, by inhibition of its activity with a specific inhibitor of PTPase (sodium orthovanadate) and by the inability to inhibit its activity with calyculin, okadaic acid, trifluoperazine, calcium, EGTA, and EDTA, which are specific inhibitors of other protein phosphatases, namely PP-1, PP-2A, PP-2B, and PP-2C respectively. The specific activity of the protein tyrosine phosphatase both in the caput and cauda epididymal sperm plasma membranes was similar, implying that the enzyme may not be solely responsible for the differential phosphorylation of membrane proteins observed during maturation (Uma Devi et al. 1997. Mol Reprod Dev 47:341-350). Thus the significance of the PTPase activity in epididymal maturation still remains to be determined. The membrane-associated PTPase may not be essential for acquisition of motility. However, it appears that the activity is essential for the sustenance of motility since sodium orthovanadate, which specifically inhibits PTPase activity, also inhibits motility of spermatozoa and decreases the overall velocity of the spermatozoa by decreasing the average path velocity, straight line velocity, curvilinear velocity, and amplitude of lateral head displacement of the treated spermatozoa.

Animals↗
PubMed1996

The effect of induced fever on the biokinetics of norfloxacin and its interaction with probenecid in goats.

The kinetic profiles of norfloxacin were evaluated in afebrile, febrile and probenecid pre-treated (70 mg/kg orally) febrile goats after a single intravenous (i.v.) dose (5 mg/kg). Fever was induced and maintained for 12 h by injecting Escherichia coli endotoxin (0.2 microgram/kg, i.v.) and repeating it in half the dose (0.1 microgram/kg) 5 h later. The plasma pharmacokinetic values for norfloxacin were best represented using a two-compartment open model. The peak norfloxacin plasma level of 90.52 +/- 3.18 micrograms/ml attained in the probenecid pre-treated febrile goats was higher than that in the febrile (75.46 +/- 0.72 micrograms/ml) or afebrile goats (62.25 +/- 1.23 micrograms/ml). ClB and Kel values were significantly (p < 0.01) decreased in febrile compared with afebrile goats. These values were further reduced in febrile goats after probenecid pre-treatment. However, t1/2 beta was not affected by the fever-probenecid interaction. Norfloxacin may be used as an infusion with probenecid in caprine diseases where very high plasma levels are required to combat resistant organisms such as Bacteroides.

Analysis of Variance↗
PubMed1989

Indolinone derivatives as potential antimicrobial agents.

1-substituted aminomethyl-3-cyclohexylthiosemicarbazone-2-indolinones (I) were tested for their antibacterial activity against Bacillus pumilis, Bacillus brevis and Bacillus megaterium and antifungal activity against Aspergillus flavus, Aspergillus fumigatus and Aspergillus niger. The majority of the compounds were found to exhibit promising antibacterial and antifungal activities. These compounds were also screened for their antiviral action against tobacco mosaic virus in Nicotiana glutinosa plants in vivo as well as in vitro. Most of the compounds had shown significant antiviral activities both in vivo and in vitro.

Anti-Bacterial Agents↗
PubMed1987

Effect of the boiling and decanting method of Khesari (Lathyrus sativus) detoxification, on changes in selected nutrients.

It is a well-known fact that the legume Khesari (Lathyrus sativus) causes lathyrism, a disease characterized by paralysis of the lower limbs in human beings. The toxic constituent is an amino acid identified as B-Oxalyl-Amino L-Alanine (BOAA). It has been reported that if the legume is boiled for two hours and the water is then decanted, almost 85% of the toxic amino acid is eliminated. Therefore, this investigation constitutes an effort to prevent the loss of other nutrients, simultaneously to the elimination of toxicity. As has been observed, as much as half the protein content, as well as 80.36% total sugars, 63.13% reducing sugars, 86.05% amino acids, and all thiamine, riboflavin and niacin are lost from dahl (dehulled, separated cotyledons), while the respective losses from the whole seeds are 47.25%, 45.73%, 74.69% and 80.00%, and all vitamins, in just a one-hour treatment. The losses of the toxic amino acid from dahl and whole seeds are 71.46% and 68.74%, respectively. The data for losses occurring in the two-hour and three-hour treatment are also described.

Amino Acids↗