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Biomedical subjects

S Mahadevan

Publications and source records attributed to S Mahadevan.

At least 73 records · Page 4Linked to original sources
PubMed1997

Poliomyelitis trends in Pondicherry, south India, 1989-91.

STUDY OBJECTIVES: To assess the poliomyelitis trend, including study of the epidemiological features, and to correlate this with the immunisation coverage of infants. DESIGN: Three annual lameness surveys in children aged 0-60 months employing cluster sampling methods and a series of five cross sectional surveys of immunisation coverage in children aged 12-23 months of age were undertaken. SETTING: Pondicherry, India, 1988-92. SUBJECTS: More than 10,000 children in the age group of 0-60 months took part in the three annual lameness surveys and samples of 210 children aged 12-23 months were covered each year in immunisation coverage surveys. MEASUREMENTS AND MAIN RESULTS: Altogether 50 of 11,461, 24 of 10,093, and 17 of 11,218 children surveyed during 1989, 1990, and 1991 respectively had become lame as a result of poliomyelitis, giving prevalences of 4.4, 2.4, and 1.5 per 1000 children for the three surveys. The corrected prevalences of poliomyelitis were 5.9, 3.2, and 2.0 per 1000 children during 1989, 1990, and 1991 respectively. The proportion of cases aged up to 36 months fell from 48% in 1989 to 12.5% in 1990 and 6% in 1991. The age at onset was less than 1 year in most. The median age at onset was 10.7 months. About 54% of the affected children had received three doses of oral poliomyelitis vaccine (OPV) before the onset of paralysis. In 1988 immunisation coverage for the third dose of OPV was 91% and in 1992 it was 97.6%. The drop out rate for the first versus the third dose of OPV fell from 6.3 in 1988 to 1.9% in 1992. CONCLUSION: Three successive annual lameness surveys showed that poliomyelitis was declining between 1989 and 1991. Five immunisation coverage surveys conducted from 1988 to 1992 showed high initial coverage followed by an improvement in the form of almost universal coverage for OPV.

Age Factors↗
PubMed1996

Duodenal flow of microbial and feed nitrogen in sheep fed normal soybean meal or soybean meal treated with modified zein.

The effect of protecting soybean meal from microbial degradation in the rumen on duodenal flow of microbial N and feed N was studied with sheep. The soybean meal was protected with chemically modified zein. Two groups of four wethers, each equipped with a ruminal cannula and a duodenal reentrant cannula, were fed a diet based on corn silage (1 kg of DM/d) that contained either a normal or protected soybean meal supplement. The results showed no appreciable differences between the two supplements in ruminal fluid pH, total N, and NAN concentrations; however, the concentration of total VFA was lower for protected soybean meal than for normal soybean meal. Although the flow of NAN into the duodenum was not affected, bacterial N flow was 18% lower, and feed N flow was 195% higher, for protected soybean meal than for normal soybean meal. The digestibilities of OM, ADF, and N in the digestive tract were not affected by the type of supplement. The treatment of soybean meal decreased the degradability of total feed N in the stomach by 22 percentage points, but the increased supply of feed N into the small intestine because of the treatment was at the expense of decreased bacterial synthesis of protein in the rumen, probably because of a shortage of RDP in the diet.

Animal Feed↗
PubMed1995

Transcriptional activation of the Escherichia coli bgl operon: negative regulation by DNA structural elements near the promoter.

The bgl operon of Escherichia coli is transcriptionally inactive in wild-type cells. DNA insertion sequences (IS) constitute a major class of spontaneous mutations that activate the cryptic bgl promoter. In an attempt to study the molecular mechanism of activation mediated by insertion sequences, transcription of the bgl promoter was carried out in vitro. Stimulation of transcription is observed when a plasmid containing an insertionally activated bgl promoter is used as a template in the absence of proteins other than RNA polymerase. Deletions that remove sequences upstream of the bgl promoter, and insertion of a 1.2 kb DNA fragment encoding resistance to kanamycin, activate the promoter. Point mutations within a region of dyad symmetry upstream of the promoter, which has the potential to extrude into a cruciform structure under torsional stress, also lead to activation. Introduction of a sequence with dyad symmetry, upstream of an activated bgl promoter carrying a deletion of upstream sequences, results in a fourfold reduction in transcription. These results suggest that the cryptic nature of the bgl promoter is because of the presence of DNA structural elements near the promoter that negatively affect transcription.

Base Sequence↗
PubMed1995

Increased milk production of cows in early lactation fed chemically treated soybean meal.

Holstein cows in early lactation and producing about 35 kg/d of milk were fed TMR for ad libitum intake and 1 kg/d of long alfalfa hay. Soybean meal and soybean meal treated by a novel technique were compared in diets of 15 and 17% CP in a 2 x 2 factorial design. Digestibilities of DM, CP, and ADF were significantly lower for treated soybean meal diets. Mean DMI was about 21 kg/d and was unaffected by treatment. Milk production was significantly increased during wk 7 to 16 of lactation for cows fed treated soybean meal diets. The production of SCM and milk components was greater for cows fed treated soybean meal than for cows fed soybean meal, but the differences were not significant. By wk 16, compared with wk 3 of lactation, the persistency of production of milk and lactose was markedly increased by treated soybean meal. The persistency of milk protein production was 100.5% for cows fed the diet containing treated soybean meal at 17% CP and about 97% for the other diets. The hypothesis that Met supply was limiting secretion of milk protein in cows fed treated soybean meal is discussed.

Animal Feed↗
PubMed1995

Isolation of Japanese encephalitis virus from mosquitoes collected in Sabak Bernam, Selangor, Malaysia in 1992.

Detection and isolation of Japanese encephalitis (JE) virus were attempted from female mosquitoes collected in Kampong Pasir Panjang, Sabak Bernam, Selangor, from May to November 1992. A total of 7,400 mosquitoes consisting of 12 species in 148 pools were processed and inoculated into Aedes albopictus clone C6/36 cell cultures. Of these, 26 pools showed the presence of viral antigens in the infected C6/36 cells by specific immunoperoxidase staining using an anti-JE virus polyclonal antibody. Presence of JE virus genome was confirmed in the infected culture fluid for 16 pools by using reverse transcriptase-polymerase chain reaction and JE virus-specific primers. Of these, 3 pools were from Culex tritaeniorhynchus, 4 from Culex vishnui, 3 from Culex bitaeniorhynchus, 2 from Culex sitiens, one from Aedes species, and 3 from Culex species. Isolation of JE virus from Cx. sitiens, Cx. bitaeniorhynchus, and Aedes sp. (Aedes butleri and Ae. albopictus) is reported for the first time in Malaysia.

Aedes↗
PubMed1995

The impact of permethrin impregnated bednets on the malaria vector Anopheles maculatus (Diptera: Culicidae) in aboriginal villages of Pos Betau Pahang, Malaysia.

The effect of permethrin impregnated bednets on Anopheles maculatus Theobald was studied in four villages in Pos Betau, Pahang, Malaysia from August 1990 to July 1992. Collections of mosquitos were carried out indoors and outdoors from 1900 to 0700 hours. All mosquitos were dissected for sporozoites and parity. In May 1991 two villages received bednets impregnated with permethrin at 0.5 g/m2 and two villages received placebo bednets. There was a significant difference in the sporozoite and parous rates between the treated and control villages after the distribution of bednets (p < 0.05). There was no significant difference in the bites/man/night of An. maculatus between the pre and post treatment periods in the control villages. However there was a significant difference in bites/man/night between pre and post treatment in the treated villages (p < 0.001).

Animals↗
PubMed1994

The cDNA sequence of cytochrome b5 associated with cytokinin-induced haustoria formation in Cuscuta reflexa.

A cDNA clone isolated by differentially screening a cytokinin-induced haustorial cDNA library of Cuscuta reflexa was sequenced and identified as the gene coding for cytochrome b5, based on the similarity of the deduced amino-acid sequence with that of the cauliflower (60% identity) and tobacco (78% identity) proteins. The 5'-UTR is unusually long (720 bp) and contains 14 potential start codons (ATG) and 10 short ORFs.

Amino Acid Sequence↗
PubMed1994

Cloning and sequence of a cDNA encoding a novel hybrid proline-rich protein associated with cytokinin-induced haustoria formation in Cuscuta reflexa.

A complete cDNA encoding a novel hybrid Pro-rich protein (HyPRP) was identified by differentially screening 3 x 10(4) recombinant plaques of a Cuscuta reflexa cytokinin-induced haustorial cDNA library constructed in lambda gt10. The nucleotide (nt) sequence consists of: (i) a 424-bp 5'-non coding region having five start codons (ATGs) and three upstream open reading frames (uORFs); (ii) an ORF of 987 bp with coding potential for a 329-amino-acid (aa) protein of M(r) 35,203 with a hydrophobic N-terminal region including a stretch of nine consecutive Phe followed by a Pro-rich sequence and a Cys-rich hydrophobic C terminus; and (iii) a 178-bp 3'-UTR (untranslated region). Comparison of the predicted aa sequence with the NBRF and SWISSPROT databases and with a recent report of an embryo-specific protein of maize [Jose-Estanyol et al., Plant Cell 4 (1992) 413-423] showed it to be similar to the class of HyPRPs encoded by genes preferentially expressed in young tomato fruits, maize embryos and in vitro-cultured carrot embryos. Northern analysis revealed an approx. 1.8-kb mRNA of this gene expressed in the subapical region of the C. reflexa vine which exhibited maximum sensitivity to cytokinin in haustorial induction.

Amino Acid Sequence↗
PubMed1994

Adenosine for the prehospital treatment of paroxysmal supraventricular tachycardia.

STUDY OBJECTIVE: To determine the efficacy and feasibility of adenosine for the treatment of paroxysmal supraventricular tachycardia (PSVT) in the prehospital setting. DESIGN: Prospective case series. SETTING: Large, urban, advanced life support emergency medical services system. PARTICIPANTS: One hundred twenty-nine adult patients with PSVT, as identified by paramedic personnel. Pregnant patients and those taking carbamazepine or dipyridamole were excluded. INTERVENTIONS: Dose of 12 mg adenosine by rapid i.v. push followed by a 5-mL saline flush and a repeat dose of 12 mg adenosine i.v. push if the patient's rhythm remained unchanged. MEASUREMENTS AND MAIN RESULTS: Six-second lead II rhythm strips and vital signs were documented before and 2 minutes after the administration of adenosine. Demographic information, past medical history, medications, number of adenosine doses given, and complications were recorded by the paramedic on a case-report form. One hundred six of 129 (82%) of the case-report forms included the rhythm strips from before and after adenosine administration. Actual initial rhythms were determined by a consensus panel. The initial rhythms were PSVT in 79% (84 of 106) of patients, atrial fibrillation in 12% (13 of 106), sinus tachycardia in 5% (five of 106), atrial flutter in 2% (two of 106), and ventricular tachycardia in 2% (two of 106). Eighty-five percent (71 of 84) of patients in PSVT were successfully converted to sinus rhythms; four (5.6%) of these patients required a second 12-mg dose. One patient in atrial fibrillation spontaneously converted to normal sinus rhythm and one patient in ventricular tachycardia converted after adenosine. All other patients not initially in PSVT remained in their initial rhythm. Complications occurred in 12 of 129 patients and included chest pain (five), flushing (three), shortness of breath (two), nausea (one), anxiety (one), dizziness (one), headache (one), and seizure (one). All complications were transient and required no treatment. Prior history of PSVT was the only variable associated with a higher rate of conversion (P = .029). CONCLUSION: Paramedics are able to accurately identify PSVT using a single lead. Adenosine is safe and effective treatment for PSVT in the prehospital setting. This series is the largest prehospital study of adenosine use to date.

Adenosine↗
PubMed1994

Comparative metabolism of deltamethrin and 3-phenoxybenzoic acid in chickens.

A comparative metabolism of [benzyl 14C]deltamethrin and 3-phenoxybenzoic acid (3-PBacid) was carried out in chickens. The effect of oral and intravenous route of administration was also investigated. There was no difference in the metabolic profile of [14C] portion of deltamethrin and 3-PBacid. Similarly, no effect on the nature of metabolites excreted due to mode of administration was observed. Biotransformation of orally dosed compounds did not occur in the intestine, but were absorbed and metabolized by liver (deltamethrin) and kidney (3-PBacid). 3-PBacid, the primary metabolite of deltamethrin, was readily metabolized into 3-hydroxy benzoic acid (3-HO-Bacid) which is conjugated with a variety of endogenous substances to form sulphates, glucuronides, butyl ester and peptides. HPLC and LC-Ms methods were used to ascertain the structures of metabolites.

Administration, Oral↗
PubMed1994

Studies on adult mosquito vectors of Japanese encephalitis in a pig farm in Selangor, Malaysia.

Mosquito collections were carried out for a period of one year from January to December 1992 in a pig farm in Sungai Pelek, Selangor, Malaysia. A total of 41,022 mosquitos belonging to 52 species and 20 genera were collected. Culex tritaeniorhynchus and Cx. gelidus, the important vectors, comprised 63% of all mosquitos collected. Both these species were collected in large numbers during the wet months of May and December. The other predominant species in that area were Cx. fuscocephala, Cx. quinquefasciatus, Cx. sitiens, Aedes butleri, and Armigeres subalbatus.

Animal Husbandry↗
PubMed1994

Cutaneous ulcers in typhoid fever.

Cutaneous lesions in typhoid fever are uncommon. We report cutaneous ulcers in two children (aged 10 years and 3 years) with typhoid fever.

Child↗
PubMed1994

Isolation of Japanese encephalitis virus from Culex sitiens mosquitoes in Selangor, Malaysia.

Isolation of Japanese encephalitis virus (JEV) from mosquitoes in Sabak Bernam, Selangor, Malaysia, was attempted. An aliquot of homogenate from each pool of mosquitoes, 50 per tube, was inoculated into Aedes albopictus clone C6/36 cells for virus isolation. Each cell culture was tested for the presence of viral antigen by immunoperoxidase staining using an anti-JEV polyclonal antibody. Out of 4 Culex sitiens mosquito pools, 2 pools were positive for JEV by cell culture. Presence of JEV genome in the cell cultures for Cx. sitiens was confirmed by using reverse transcriptase-polymerase chain reaction and JEV-specific primers. This is the first report on the isolation of JEV from Cx. sitiens.

Aedes↗
PubMed1993

Cleavage of 3-phenoxybenzoic acid by chicken microsomal preparations.

3-Phenoxybenzoic acid, labelled at either the 3-phenoxy[U-ring C-14] or carbonyl C-14, produced the corresponding labelled transitory metabolite 4'-hydroxy-3-phenoxybenzoic acid when incubated with chicken liver microsomal preparation. The other radioactive reaction product identified from the metabolism of the carbonyl-labelled 3-phenoxybenzoic acid was labelled 3-hydroxybenzoic acid, whereas metabolism of the [U-ring] labelled 3-phenoxybenzoic acid produced labelled hydroquinone in addition to 4'-hydroxy-3-phenoxybenzoic acid. Formation of both 4'-hydroxy-3-phenoxybenzoic acid, and its subsequent conversion to 3-hydroxybenzoic andhydroquinone were NADPH and oxygen dependent. The reaction was inhibited by carbon monoxide, but not by piperonyl butoxide or metyrapone. The inhibition by carbon monoxide suggests that the enzyme(s) involved in the cleavage is a form of P450. The enzyme(s) is a monooxygenase and has requirement for NADPH and oxygen.

2,2'-Dipyridyl↗
PubMed1993

Short course chemotherapy for tuberculosis in children.

In order to determine the efficacy of short course chemotherapy (SCC) for tuberculosis in children, 83 newly diagnosed cases in children < 12 years old were given SCC and were prospectively followed for 1-3 years. Seventy-one cases were treated for 6-9 months as they had mild to moderate involvement. Twelve cases were treated for 12 months as they had meningitis (7), disseminated tuberculosis (2), or miliary tuberculosis (3). The results showed that none of the children, at the end of follow up, showed evidence of active tuberculosis. All children tolerated the drugs well, with side effects noticed being mild, namely transient hepatitis (4), vomiting (1), and skin rash (1). It is suggested that SCC for 6-9 months using isoniazid (INH) and rifampicin along with other drugs when necessary is highly effective in most cases of tuberculosis in children and has several advantages over conventional chemotherapy of 18 months or longer duration.

Adolescent↗
PubMed1993

The prevalence of mental disorders in school-age children attending a general paediatric department in southern India.

This study was conducted over a period of 18 months in a medical college hospital in southern India. Of 313 children of age 5 and above referred for detailed psychiatric evaluation, 101 were found to have a mental disorder according to DSM-III-R criteria; the remaining had organic disorders. Children above 8 years (74%) registered higher morbidity. There was no sex difference in overall morbidity. Precipitating factors were discernible in half of these cases, of which school-related problems were found in the majority. Almost two-thirds had multiple stressors, of which chronic family and social adversity (39%) and learning disabilities (28%) were common. Mental disorders were significantly related to urban background, middle-class socioeconomic status and literate parents compared with age- and sex-matched controls. There was no significant relationship with the type of family and number of siblings. Conversion disorder (31%) was the commonest, followed by conduct disorders (16%). The symptoms, stressors, response to treatment and the transcultural aspects are also discussed.

Adolescent↗