PubMed Health⌕ Search

Biomedical subjects

P Ahuja

Publications and source records attributed to P Ahuja.

At least 19 recordsLinked to original sources
PubMed2005

Decreased glutathione transferase levels in rd1/rd1 mouse retina: replenishment protects photoreceptors in retinal explants.

Currently much attention is focused on glutathione S transferase (GST)-induced suppression of apoptosis. The objective of our studies was therefore to see if GST isoenzymes rescue photoreceptors in retinal explants from rd1/rd1 mice, in which photoreceptors degenerate rapidly. Eyes from C3H rd1/rd1 and +/+ mice were collected at various time points between postnatal day (PN) 2 and PN28. Localization and content of alpha-GST and mu-GST was investigated by immunofluorescence and semi-quantitative Western blot analysis, respectively. In addition, PN2 and PN7 retinal explants were cultured till PN28, during which they were treated with 10 ng/ml alpha-GST or mu-GST. The spatiotemporal expression of both GST isoforms was closely similar: early presence in ganglion cell layer after which staining became restricted to Muller cells (particularly in the endfeet) and horizontal cell fibers in both rd1/rd1 and +/+. Doublets of alpha-GST and mu-GST were detected by Western blot analysis. Densitometry of these bands indicated steady reduction of alpha-GST content in rd1/rd1 retina starting from the second postnatal week. When alpha-GST and mu-GST were added exogenously to rd1/rd1 explants, photoreceptor rescue was produced that was more prominent in PN2 than in PN7 explants and more effective by alpha-GST than mu-GST. We propose that alpha-GST neuroprotection is mediated by reduction of tissue oxidative stress.

Animals↗
PubMed2001

Lens epithelium-derived growth factor (LEDGF) delays photoreceptor degeneration in explants of rd/rd mouse retina.

Lens epithelium derived growth factor (LEDGF) has been shown to rescue embryonic chick photoreceptor cells from serum starvation and heat stress, light damaged photoreceptor cells in Lewis rats, and photoreceptor cells in RCS rats. The aim of our study is to study the rescue effect of LEDGF on photoreceptor cells in the rd/rd mouse using our long-term serum free organ culture. At the end of this culture period of 21-26 days LEDGF treated rd mouse retina showed an increased photoreceptor survival compared to the untreated controls. LEDGF has no effect on expression and localization of opsin and arrestin in the rod photoreceptor cells when RPE is present. The protective potency of LEDGF on the retinal photoreceptor cells is similar to that of BDNF. LEDGF is known to activate heat shock proteins (Hsps) and the elevated Hsps are also reported to suppress apoptosis.

Aging↗
PubMed2001

Reduced uptake as a mechanism of zinc tolerance in Oscillatoria anguistissima.

Oscillatoria anguistissima could tolerate 50 ppm ZnSO4 x 7H2O, and a zinc-tolerant strain with maximum tolerance concentration (MTC) of 100 ppm ZnSO4 x 7H2O was obtained by stepwise transfer to higher concentrations. The adaptation was irreversible even after three generations in metal-free medium. In the presence of metal, the tolerant strain grew with a shorter lag period of 4 days as against 6 days in the case of the wild strain. The tolerant strain had higher MTC than that of the wild strain for other metals also, viz., Ni2+, Co2+, Cu2+ and Cd2+. The zinc resistance in the tolerant strain was a result of reduced uptake, since around 42% of the total metal was present on the surface as against only 30% in the wild strain. The calcium-stimulated uptake, as observed in the wild strain, was absent in the tolerant strain. Ultrastructural comparisons revealed no structural change in the tolerant strain on exposure to zinc, whereas in the wild strain a thick extracellular matrix was observed.

Adaptation, Physiological↗
PubMed2001

Mouse retina explants after long-term culture in serum free medium.

The neonatal mouse retina remains viable as an explant in serum-supplemented growth media for more than 4 weeks. Interpretation of drug effects on this tissue is compromised by the enigmatic composition of the serum. We sought to remove this ambiguity by culturing neonatal as well as late postnatal mouse retina in serum-free nutrient medium. In this study three important observations were made, (1) there is histotypic development of neonatal as well as preservation of late postnatal mouse retinal structure during long-term culture in serum-free medium, although the late postnatal tissue tends to show some loss of cells in the outer nuclear layer. (2) Protein expression in explant photoreceptor cells was similar to that in the litter-matched ones, except for green cone opsin and interphotoreceptor retinoid-binding protein, although mRNA of the latter is present at similar amounts as in age-matched in vivo controls. (3) Cells of the inner retina stained by antibodies to calcium-binding proteins display some novel sprouting of processes. The results show that the mouse retina can be cultured as an explant for more than 4 weeks in a serum-free medium. This represents an important step forward because, (1) the possibility of interference of drug effects by unknown serum factors has been eliminated; and (2) the spent culture medium can be analyzed to investigate biomolecules released by the retina in vitro.

Animals↗
PubMed1999

Sorption and desorption of cobalt by Oscillatoria anguistissima.

Oscillatoria anguistissima rapidly adsorbs appreciable amounts of cobalt from the aqueous solutions within 15 min of initial contact with the metal solution. O. anguistissima showed a high sequestration of cobalt at low equilibrium concentrations, and it followed the Freundlich model of adsorption. The adsorption is a strongly pH-dependent and temperature-independent phenomenon. The presence of Mg2+ and Ca2+ (100-200 ppm) resulted in decline in Co2+ adsorption capacity of Oscillatoria biomass. Sulphate and nitrate (0. 75-10 mM) drastically reduced the extent of Co2+ biosorption. The biosorption of cobalt is an ion-exchange process as the Co2+ binding was accompanied by release of a large amounts of Mg2+ ions. Na2CO3 (1.0 mM) resulted in about 76% desorption of Co2+ from the loaded biomass.

Adsorption↗
PubMed1997

Oscillatoria anguistissima: a promising Cu2+ biosorbent.

Oscillatoria anguistissima rapidly adsorbs Cu2+ from aqueous solution. The adsorption of Cu2+ followed Freundlich Isotherm, and the amount of Cu2+ removed from solution increased with increasing Cu2+ concentration. The adsorption is pH dependent, and maximum Cu2+ removal occurs at pH 5. Of the various pretreatments, HCl treatment of the biomass increased the capacity for Cu2+ removal. Presence of Mg2+ and Ca2+ resulted in decline in the Cu2+ adsorption capacity of Oscillatoria cells. This species could also effectively remove Cu2+ from mine water containing 68.4 microg/ml of Cu2+ at pH 3.45.

Adsorption↗
PubMed1994

p-Aminobenzene sulphonyl morpholine, compound 82/208 a new anticonvulsant agent.

p-Aminobenzene sulphonyl morpholine, compound 82/208, was evaluated for acute toxicity and anticonvulsant action in mice against tonic seizures induced by supramaximal electroshock and pentylene tetrazole and strychnine induced seizures and for its effect on blood pressure and respiration in cat. Diphenyl hydantoin (DPH) was used as reference standard. Compound 82/208 exhibited anticonvulsant activity against electroshock induced seizures and PTZ induced tonic seizures in mice. The compound had several distinct advantages over DPH in experimental evaluation in mice.

Animals↗