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Biomedical subjects

M S Nair

Publications and source records attributed to M S Nair.

At least 19 recordsLinked to original sources
PubMed2001

Triterpenoids from Dysoxylum malabaricum.

Two triterpenes 21R,23R-epoxy-21alpha-ethoxy-24S,25-dihydroxyapotirucall-7-en-3-one and 24R-acetoxy-3beta,25-dihydroxycycloartane were isolated from the leaves of Dysoxylum malabaricum together with eight known compounds lupeone, lupeol. sitosterol, dipterocarpol, cycloart-25-ene-3beta,24-diol, 24R,25-dihydroxycycloartan-3-one, 3beta,24R,25-trihydroxycycloartane and ergosta-5,24(24(1))-diene-3beta,4beta,20S-triol. The complete 1H and 13C NMR spectral assignment of the new apotirucallene triterpenoid has been achieved by 1H-1H COSY, HMQC and HMBC experiments.

India↗
PubMed1993

Bioconversion of arteannuin B to artemisinin.

Arteannuin B, which co-occurs with artemisinin, the potent antimalarial principle of the Chinese medicinal herb Artemisia annua (Asteraceae), has been converted to the latter using crude and semi-purified cell-free extracts of the leaf homogenates of the plant. Detection procedures to quantitate this bioconversion, including one that is novel which uses gcms, are detailed.

Artemisinins↗
PubMed1982

Isolation and structural elucidation of an ichthyocrinotoxin from the smooth trunkfish (Lactophrys triqueter Linnaeus).

An ichthyocrinotoxin has been isolated from the skin secretion of the smooth trunkfish, Lactophrys triqueter Linnaeus (family Ostraciidae). A crystalline toxin was isolated and identified as the choline chloride ester of palmitic acid. The toxin has a minimum lethal concentration of 2 ppm and an LC50 of 3.5 ppm using mosquito fish as the test organism. A trace quantity of the choline ester chloride of heptadecanoic acid was identified as a minor component of the toxin.

Animals↗
PubMedDate not supplied

Electrical impedance cardiography using artificial neural networks.

This study evaluates the use of artificial neural networks to estimate stroke volume from pre-processed, thoracic impedance plethysmograph signals from 20 healthy subjects. Standard back-propagation was used to train the networks, with Doppler stroke volume estimates as the desired output. The trained networks were then compared to two classical biophysical approaches. The coefficient of determination (R2 x 100%) between the biophysical approaches and the Doppler was 8.20% and 9.90%, while it was 77.38% between the best neural network and the Doppler. Among these methods, only the neural network residuals had a significant zero mean Gaussian distribution (alpha=0.05). Our results indicate that an invertible relationship may exist between thoracic bioimpedance and stroke volume, and that artificial neural networks may offer a potentially advantageous approach for estimating stroke volume from thoracic electrical impedance, both because of their ease of use and their lack of confounding assumptions.

Adult↗
PubMedDate not supplied

Carcinoma gall bladder presenting as hemobilia.

A 60-year-old man presented with recurrent bouts of melena, requiring multiple transfusions. Upper GI endoscopic evaluation demonstrated fresh bleeding from the ampulla of Vater. Ultrasonography and CT scan suggested a gall bladder mass without evidence of metastases. Laparotomy confirmed a mass confined to the lumen of the gall bladder. The patient underwent cholecystectomy. Histological examination showed papillary adenocarcinoma of the gall bladder extending up to the muscularis propria.

Adenocarcinoma, Papillary↗