PubMed Health⌕ Search

Biomedical subjects

U Pathak

Publications and source records attributed to U Pathak.

5 recordsLinked to original sources
PubMed2002

In vivo protection by amifostine and DRDE-07 against sulphur mustard toxicity.

The study was aimed at investigating the prophylactic efficacy of orally administered amifostine and a newly synthesized compound, S-2(2-amino-ethylamino)ethyl phenyl sulphide (DRDE-07), against dermally applied sulphur mustard (SM) in mice and rats. The LD50 values of amifostine and DRDE-07 were determined following oral and intraperitoneal routes and the LD50 of SM diluted in PEG-300 was determined following dermal route. Amifostine or DRDE-07 (equivalent to their 0.05 LD50, 0.10 LD50 and 0.20 LD50) dissolved in water was fed to mice and rats and, after 30 min, various doses of SM were applied to the hair-clipped area of the skin and were observed for 14 days for mortality. The protection index (PI) was calculated as a ratio of LD50 with treatment to LD50 without treatment. The estimated percutaneous LD50 of SM was found to be 8.1 and 2.4 mg/kg for female mice and male rats, respectively. A dose-related protection was observed with all the three doses of both compounds. Thirty minutes prior, the administration of amifostine in female mice offered a PI of 3.0 at the lowest pretreatment dose (52.5 mg/ kg) followed by PI of 6.7 and 9.5 at 105 and 210 mg/kg pretreatment doses, respectively. DRDE-07 offered better protection against SM in female mice, i.e., a PI of 4.8 at pretreatment dose of 62.5 mg/kg, a PI of 12.0 at the dose of 124.7 mg/kg and a PI of 27.0 at the dose of 249.4 mg/kg. In male rats, DRDE-07 gave a PI of about 3.0 at all the three pretreatment doses (80, 160 and 320 mg/kg), whilst amifostine offered a PI of 3.1 at the highest pretreatment dose (452 mg/kg). The present study showed that oral administration of both amifostine and DRDE-07 was effective as a prophylactic agent for protecting against SM toxicity, and that DRDE-07 offered better protection.

Administration, Cutaneous↗
PubMed2001

Protective effects of amifostine and its analogues on sulfur mustard toxicity in vitro and in vivo.

Sulfur mustard (bis(2-chloroethyl)sulfide, SM) is a highly reactive bifunctional alkylating agent that forms sulfonium ions in the body. SM alkylates DNA, leading to DNA strand breaks and cell death in a variety of cell types and tissues. Although several approaches have been proposed to challenge the toxic action(s) of SM, no satisfactory treatment regimen has evolved. The synthetic aminothiol amifostine, earlier known as WR-2721 (S-2-(3-aminopropylamino)ethyl phosphorothioate), has been extensively used as a chemical radioprotector for the normal tissues in cancer radiotherapy and chemotherapy. SM is known as a radiomimetic agent and this prompted us to evaluate the protective efficacy of amifostine (2.5 mM) and three of its analogues, DRDE-06 (S-2 (3-aminopropylamino) ethyl phenyl sulfide), DRDE-07 (S-2 (2-aminoethylamino) ethyl phenyl sulfide), and DRDE-08 (S-2 (4-aminobutylamino) ethyl phenyl sulfide), against SM toxicity in rat liver slices. Of the four agents tested, a 30-min pretreatment of amifostine and DRDE-07 enhanced the LC50 (a concentration producing 50% leakage of lactate dehydrogenase (LDH) or alanine aminotransferase (ALT)) of SM by 5.9- and 3.3-fold for LDH and 10.2- and 5.5-fold for ALT, respectively. Except DNA fragmentation, both these agents significantly attenuated the loss of intracellular K(+) and mitochondrial integrity (MTT assay), depletion of GSH levels, and histopathology produced by a toxic concentration (80 microM) of SM. However, when amifostine and DRDE-07 were introduced 2 h after SM, no significant protection was observed. SM (77.5 or 155 mg/kg) was also applied dermally on female albino mice and challenged by 0.20 LD50 (po) of amifostine, DRDE-06, DRDE-07, or DRDE-08 at -30 min, 0 min, or +6 h. Protection was observed only when the agents were administered at -30 min or 0 min; posttreatment (+6 h) did not offer any protection. The magnitude of in vivo protection was in the following order: DRDE-07 >or= amifostine > DRDE-08 > DRDE-06. Gas chromatographic analysis showed that there was no direct chemical interaction between SM and the antidotes. The po LD50s of amifostine, DRDE-06, DRDE-07, and DRDE-08 were 1049, 1345, 1248, and 951 mg/kg, respectively. Both in vitro and in vivo data indicate promising roles of amifostine and DRDE-07 as prophylactic agents against SM poisoning.

Amifostine↗
PubMed1994

Infant growth charts.

Detection and monitoring childhood growth disorders requires the correct use of growth charts. A check on the accuracy of every point plotted on Gairdner-Pearson growth charts of premature infants in a hospital paediatric department was carried out. Errors beyond set limits were recorded. Of 611 points plotted on the growth charts of 50 premature infants who were at least 1 year of age at the time of the study, there were 173 (28.5%) points plotted in error. Altogether 94.7% of the errors occurred when plotting the age along the horizontal (X) axis of the growth chart, irrespective of whether weight, length, or head circumference was being measured. There was no evidence that the errors caused appreciable changes in clinical management. Potential sources of error identified were failure to adjust for prematurity correctly, inaccuracy in calculating age, and the use of the logarithmic scale. These errors could be serious and it is important that there should be greater vigilance in using growth charts. The use of age calculators or improved chart design is recommended. Assessment of the use of other growth charts in different settings is also suggested.

Anthropometry↗
PubMedDate not supplied

Evaluation of analogues of DRDE-07 as prophylactic agents against the lethality and toxicity of sulfur mustard administered through percutaneous route.

Sulfur mustard (SM), chemically bis (2-chloroethyl) sulfide is a bifunctional alkylating agent that causes serious blisters on contact with human skin. Although several antidotes have been reported for the systemic toxicity of SM in experimental animals none of them are approved so far and decontamination of SM immediately by physical or chemical means is recommended as the best protection. Two compounds amifostine [S-2(3-aminopropylamino) ethyl phosphorothioate] and DRDE-07 [S-2(2-aminoethylamino) ethyl phenyl sulfide] gave very good protection as an oral prophylactic agent against SM the in mouse model, but in the rat model the protection was only moderate. In the search for more effective and less toxic compounds, a number of analogues of DRDE-07 were synthesised and their protective efficacy was evaluated in mouse and rat models. The LD50 of S-aryl substitution was between 1 and 2 g kg(-1) and S-alkyl substitution was more than 2 g kg(-1). In the mouse model, DRDE-07, DRDE-10, DRDE-21, DRDE-30 and DRDE-35 gave about 20 fold protection, and DRDE-23 and DRDE-38 gave less protection of 4.8 and 9.0 fold respectively, against percutaneously administered SM. In the rat model, DRDE-07, DRDE-09, DRDE-10 and DRDE-21 gave about two fold protection. Percutaneously administered SM (19.33 mg kg(-1)) significantly depleted the hepatic GSH content in mice. Pretreatment with DRDE-21 significantly elevated the levels. A 4.4 fold increase in % DNA fragmentation was observed 7 days after SM administration (19.33 mg kg(-1)) in mice. Pretreatment with DRDE-07, DRDE-09, DRDE-10, DRDE-21, DRDE-30 and DRDE-35 significantly protected the mice from SM induced DNA damage. The histopathological lesions in liver and spleen induced by percutaneously administered SM was reduced by pretreatment with DRDE-07, DRDE-09, DRDE-10 and DRDE-21. These analogues may prove as prototypes for the designing of more effective prophylactic drug for SM.

Administration, Oral↗