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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↗
PubMed1990

Effect of oral nicardipine on anorectal function in normal human volunteers and patients with irritable bowel syndrome.

Paired controlled studies were performed in 10 normal volunteers and 32 patients with irritable bowel syndrome to investigate the effect of the calcium channel blocker nicardipine, on the responses of the anorectum to rectal distension and a meal. Nicardipine was administered orally in standard (20 mg) and sustained-release (30 mg twice a day) formulations. In normal volunteers standard nicardipine had no significant effect on the rectal responses to distension but did significantly reduce the postprandial motility index (P less than 0.05). In the patients with irritable bowel syndrome, standard nicardipine caused a significant reduction in distension-induced rectal motor activity (P less than 0.05) and increased the rectal sensory thresholds for desire to defecate and discomfort (P less than 0.02). Slow-release nicardipine caused a significant reduction in distension-induced activity (P less than 0.05) but did not alter rectal sensory thresholds. Both formulations of nicardipine significantly reduced the postprandial motility index (P less than 0.05) and symptoms (P less than 0.05). In conclusion, this study confirms that calcium channel blockers may be useful in the management of irritable bowel syndrome.

Administration, Oral↗
PubMed1990

Gastrointestinal motility in patients with ulcerative colitis.

In the first study 62 patients with ulcerative colitis and 20 healthy controls were fed a test meal of mashed potatoes and baked beans containing transit markers. Mouth-to-caecum transit was significantly slower in the patients than in controls; gastric emptying, however, was similar. Patients with active colitis had proximal colonic stasis, with rapid transit through the rectosigmoid region. In the patients with quiescent colitis the colonic distribution of markers was normal. Stool weight and frequency were significantly higher in the patients with active colitis. In the second study anorectal function was assessed in 29 patients with ulcerative colitis and in 12 healthy controls by measuring interluminal pressures at multiple sites in the anus and rectum before and during serial distention of a rectal balloon. Overall, resting and maximum squeeze sphincter pressures did not differ in patients with active or quiescent colitis and controls; however, in six patients with moderately severe colitis and incontinence, maximum squeeze pressure was significantly lower than in controls. The rectal volumes required to induce sensations of wind, a desire to defaecate, and pain were significantly lower in the patients with active colitis than patients with quiescent colitis and controls. Rectal pressures in response to rectal distention were higher in patients with active colitis. During disease remission rectal sensitivity decreased and rectal compliance increased. In the third study integrated pressure activity of the sigmoid colon, rectum, and anus was studied in patients with ulcerative colitis and healthy controls before and during provocation by rectal infusion of 1500 ml of warm saline.(ABSTRACT TRUNCATED AT 250 WORDS)

Colitis, Ulcerative↗
PubMed1989

Toxicity and metabolism of a new insect repellent N,N-diethylphenylacetamide in mice, rats and guinea pigs on cutaneous application.

Cutaneous LD50 of N,N-diethylphenylacetamide (DEPA), a new multi insect repellent was 2200, 3200 and 7100 mg/kg body weight in female mice, rats and guinea pigs; and 1600 and 4000 mg/kg in male mice and rats indicating a high degree of safety on skin contact. Dermal application of DEPA to young growing rats for 21 days at a dose of 50 mg/kg did not exert any adverse effects while massive doses of 500 and 1000 mg/kg caused marked reduction of body weight gain and lowering of activities of serum alanine aminotransferase, aspartate aminotransferase and cholinesterase. Along with DEPA, N-ethylphenylacetamide, phenylacetamide and phenylacetic acid were detected in the urine of DEPA treated mice, rats and guinea pigs.

Acetamides↗
PubMed1989

Study on dermal toxicity and urinary metabolites of the new insect repellent N,N-diethylphenylacetamide in rabbits.

Dermal toxicity of the new multi-insect repellent N,N-diethylphenylacetamide (DEPA) was studied in female rabbits. LD50 of DEPA was estimated to be 3505 mg/kg b.w. On daily topical application for 21 d at a dose of 50 mg/kg b.w., dermal irritancy score and blood chemistry changes indicated that the compound is non-irritant and non-toxic. N-Ethylphenylacetamide and conjugated phenylacetic acid were identified as the urinary metabolites of DEPA by gas-liquid chromatography.

Acetamides↗
PubMed1989

Parametric modeling of somatosensory evoked potentials.

In this paper, we examine methods of characterizing somatosensory evoked potentials (SEP's) in both the time and frequency domains. We have found that the truncated impulse response (TIR) method produced an accurate time domain model of the SEP signals at model orders greatly reduced from the original state space matrix. The TIR method was valuable for smoothing signals that were slightly corrupted by noise. In this case, the simulated data sequence was close to the original data sequence in the mean squared error sense. For signals that were greatly corrupted by noise, the TIR method was not able to perform as well. Therefore, the TIR method was not a feature extraction method but was valuable for data simulation. In the frequency domain, we have used the autoregressive moving average model (ARMA) to parameterize the SEP signal. An overdetermined set of Yule-Walker equations was created to determine the autoregressive (AR) parameters of the original data with the model order established by the singular value decomposition. From these AR parameters, a residual time series was generated which was used to find the moving average parameters. The resulting ARMA model was used to produce a simulated data sequence. The frequency domain characteristics of the simulated sequence and the corresponding power spectral density of the ARMA filter were very close to the periodogram of the original data sequence. Accurate parameterization was achieved for the SEP waveforms at low filter lengths.

Algorithms↗
PubMed1989

Olsalazine or sulphasalazine in first attacks of ulcerative colitis? A double blind study.

Olsalazine (2 g/day) and sulphasalazine (3 g/day) were compared in a double blind three centre trial in 37 patients presenting with first attack of distal colitis. Sigmoidoscopic appearances, rectal biopsies, and symptom and stool diary records were used to assess benefit and adverse effects. Both groups showed a similar decrease in stool frequency (p less than 0.001). The proportion of unformed stools was also decreased, but to a lesser extent (p less than 0.05) in those taking olsalazine (78% v 55%; p less than 0.001) compared with those taking sulphasalazine (72% v 28%; p less than 0.001). There was a diminution in the proportion of stools containing blood in both groups (olsalazine: 61% v 22%; p less than 0.001/sulphasalazine: 67% v 37%; p less than 0.001). Sigmoidoscopic and histological appearances and clinical activity improved significantly and to a similar extent in both groups. Intolerance was encountered in two patients on olsalazine and four on sulphasalazine; intolerance to sulphasalazine being even higher (five of seven patients) in a preliminary study using a dose of sulphasalazine releasing the same amount of 5-aminosalicylic acid as 2 g olsalazine. Olsalazine was at least as effective as sulphasalazine in the treatment of new patients with distal colitis, and in a dose releasing an equivalent amount of 5-aminosalicylic acid was better tolerated.

Adult↗
PubMed1989

Childbirth spacing in a rural community of Delhi: profile in various marriage cohorts by decades.

Complete retrospective fertility histories of 843 ever married women of two villages in Delhi, obtained through house to house survey, were analysed to study various marriage cohorts by decades for trends of child birth spacing over a period of 60 years from 1921 to 1980. Spacing between consummation of marriage and first child birth gradually declined over the last 6 decades. For all other subsequent livebirths remained constant at an average of nearly 30 months. Irrespective of the reasons for such a trend, much more efforts are required to be put in to increase child spacing.

Adolescent↗
PubMed1988

Pleural effusions and pancreatico-pleural fistulae associated with asymptomatic pancreatic disease.

Four patients are described in whom recurrent large pleural effusions developed secondary to asymptomatic pancreatic disease. The diagnosis was made by measuring the amylase content of the pleural fluid. Endoscopic retrograde cholangiopancreatography (ERCP) and computed tomography (CT) were useful in demonstrating pancreatico-pleural fistulae. Two patients underwent laparotomy and distal pancreatectomy. One recovered spontaneously after ERCP appeared to relieve an obstruction of the pancreatic duct and the other recovered after a period of parenteral nutrition. We suggest that pleural fluid amylase content should be measured in any case of exudative pleural effusion of unknown aetiology.

Adult↗
PubMed1988

Impaired colonic fermentation of carbohydrate after ampicillin.

The aim of this study was to investigate the effect of ampicillin on the ability of the human colon to ferment carbohydrate. The effect of ingesting a drink containing 20 g of lactulose on stool output and breath hydrogen production was measured in 13 normal volunteers before and during administration of ampicillin (2 g/day). Small bowel and whole gut transit times were also measured to exclude any direct effect of ampicillin on motor activity. Ingestion of lactulose did not increase stool weight or frequency under control conditions, but during administration of ampicillin, lactulose caused increases in stool weight (p less than 0.02) and frequency (p less than 0.01), in the percentage of unformed stools (p less than 0.001), and in the excretion of galactose and fructose in stool samples collected from 2 volunteers. Administration of ampicillin also significantly reduced the area under the breath hydrogen profile (p less than 0.03). Mouth-to-cecum transit of the lactulose drink was prolonged during ampicillin ingestion (p less than 0.01) but there was no significant change in the whole gut transit time. These results suggest that ampicillin impairs colonic fermentation of carbohydrate and a diet high in unabsorbable carbohydrate increases the risk of antibiotic-associated diarrhea.

Adult↗