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Biomedical subjects

S S Rao

Publications and source records attributed to S S Rao.

At least 19 recordsLinked to original sources
PubMed1991

Acute and subacute inhalation toxicity studies of a new broad spectrum insect repellent, N,N-diethylphenylacetamide.

N,N-Diethylphenylacetamide (DEPA) is an inexpensive, long-acting and broad spectrum insect repellent. The acute LC50 for a 4-h exposure of DEPA aerosol was found to be 1.451 mg l-1 (1.290-1.633) in male and 1.375 mg l-1 (1.307-1.447) in female rats. DEPA did not cause delayed deaths. Acute exposure to 0.9 LC50 revealed that liver might be a target organ for DEPA toxicity. On subacute exposures to 0.2, 0.6 and 0.8 LC50 for 6 h per day, 5 days a week for 2 weeks, there was no significant change in the 0.2 LC50 group, as evaluated by the body weight gain and organ body weight ratio. The minimal changes observed in the 0.6 LC50 group were of reversible type as the animals recovered on cessation of exposure. A massive concentration of 0.8 LC50 produced lethal effects. The study shows that DEPA has a low mammalian toxicity by inhalation as was found earlier with cutaneous application of the insect repellent.

Acetamides↗
PubMed1991

Distribution and metabolism of insect repellant N,N-diethylphenylacetamide on oral exposure in rats.

Oral toxicity, distribution and metabolism of a new multi-insect repellant, N,N-diethylphenylacetamide (DEPA) was studied in rats. On administration of DEPA (851 mg/kg body wt.) labelled with 14C blood, liver, stomach and stomach contents had 2.65, 3.97, 12.07 and greater than 50.66% radioactivity, respectively, after 20 min. Gas chromatographic analysis showed presence of both DEPA and its metabolite N-ethylphenylacetamide (EPA) in blood, liver, kidneys and lungs while only DEPA was present in stomach and stomach contents. EPA, phenylacetamide and conjugated phenylacetic acid were excreted along with unmetabolized parent compound in urine of rats when a low oral dose of DEPA (70 mg/kg body wt.) was administered. Activities of erythrocyte cholinesterase and carbonic anhydrase did not change significantly upon acute oral exposure to DEPA.

Acetamides↗
PubMed1991

Empowering low-income black families of handicapped children.

A qualitative study of four black, low-income, single mothers used in-depth interviews and participant observation to evaluate their interactions with outreach agency professionals. Three perceived aspects (disrespect, focus on deficits, and discounting parenting style differences) were associated with exclusionary (unempowering) relationships. A reciprocal and supportive approach was associated with collaborative (empowering) relationships. Implications of these findings for professionals serving minority families are discussed.

Adult↗
PubMed1991

Insect repellent N,N-diethylphenylacetamide: an update.

N,N-diethylphenylacetamide (DEPA) has repellent activity against hematophagous insects including mosquitoes, black flies, horse flies, muscoid flies, rat fleas, and ticks, as well as land leeches and cockroaches. The efficacy of DEPA is comparable to that of N,N-diethyl-3-methylbenzamide (DEET) in both laboratory and field tests. Toxicological studies indicate that DEPA is safe for human use. Different formulations as well as fabrics impregnated with DEPA are effective for personal protection from insect bites.

Acetamides↗
PubMed1979

Characterization of a gonadal factor involved in the control of FSH secretion.

This communication presents evidence for the existence in the ovine testis of proteinaceous factors which suppress LH as well as FSH. Isolation of these factors has been achieved by using three different procedures: cytosol preparation, metaphosphoric acid extraction and ultrafiltration. Chromatography of cytosol or metaphosphoric acid extract on Sephadex G-75 resulted in separation into three protein fractions designated as G-75-I, II and III in order of their elution. When administered to castrated male rats, Fraction G-75-I suppressed circulatory levels of LH (53% inhibition, P less than 0.05) without altering FSH. The most retarded fraction, G-75-III, suppressed FSH (29% inhibition, P less than 0.001) without any concomitant change in LH. When fraction G-75-III was further fractionated on Sephadex G-25, three components were found and two, G-25-II and G-25-III, were biologically active. These fractions were homogeneous on polyacrylamide disc-gel electrophoresis. The FSH-suppressing factor (inhibin) was heat labile and susceptible to trypsin digestion, indicating that it is proteinaceous. Treatment with urea did not reveal any subunits. The molecular weight of this factor, as determined by gel filtration and SDS-urea gel electrophoresis was estimated to be around 1400-1500. The absence of sialic acid and the molecular weight data suggested that the isolated material was a simple protein and probably a small peptide. Gel filtration on Sephadex G-75 of the metaphosphoric acid extracts of liver, kidney, testis and ovary revealed an identical elution pattern for ovarian and testicular inhibin.

Animals↗
PubMed1979

Histological grading and sequential morphological changes during the production of acute duodenal ulcers.

A method of grading histological changes in the duodenum and the sequential morphological appearances during the development of acute duodenal ulceration is described. After s.c. infusion of ulcerogenic doses of gastric secretagogues, rats were killed hourly and the duodenal lesions were graded from 1, which was the earliest change seen consisting of focal necrosis of the tips of villi to 6, which showed perforation of duodenal ulcer. For the first 4 h the duodenum was normal but after this there was progressive necrosis of the mucosa and submucosa, and inflammatory-cell infiltration. From 18 h rats were shown to have duodenal ulcers with or without perforation.

Acute Disease↗