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Biomedical subjects

P K Agrawal

Publications and source records attributed to P K Agrawal.

18 recordsLinked to original sources

NMR spectroscopy in the structural elucidation of oligosaccharides and glycosides.

The potential of one- and two-dimensional NMR techniques for the identification of individual sugar residues, their anomeric configuration, interglycosidic linkages, sequencing and the site of any appended group, in establishing the structures of naturally occurring oligosaccharides and glycosides is presented.

Carbohydrate Sequence

A spirostane hexaglycoside from Agave cantala fruits.

A new steroidal glycoside, agaveside D, isolated from the fruits of Agave cantala was characterized as 3 beta-(alpha-L-rhamnopyranosyl-(1----2),beta-D-glycopyranosyl- (1----3)-beta-D-glucopyranosyl[beta-D-xylopyransoyl-(1----4)-alpha -L-rhamnopyranosyl-(1----2)]-beta-D-glucopyranosyl)-25R-5 alpha-spirostane on the basis of chemical degradation and spectrometry.

Carbohydrate Sequence

Steroidal glycosides from Agave cantala.

Two new steroidal glycosides, agaveside A and B, isolated from the fruits of Agave cantala were characterized as 3 beta-O-[beta-D-xylopyranosyl-(1----2),beta-D-xylopyranosyl-(1----3), beta-D-glucopyranosyl-(1----3)-[beta-D-xylopyranosyl-(1----3)-beta-D- galactopyranosyl-(1----2)]-beta-D-glucopyranosyl]-(25R)-5 alpha-spirostane and 3 beta-O-[beta-D-xylopyranosyl-(1----2), beta-D-xylopyranosyl-(1----3)-beta-D-glucopyranosyl-(1----3)- [beta-D-galactopyranosyl-(1----2)]-beta-D-glucopyranosyl]-(25R)-5 alpha-spirostane. The structures were elucidated by a combination of 13CNMR spectroscopy, chemical degradation and fast atom bombardment mass spectrometry.

Carbohydrate Conformation

Orbital paecilomycosis due to Paecilomyces lilacinus (Thom) Samson.

The first case of orbital paecilomycosis is described. Fungal hyphae were found in a KOH preparation of the granulomatous tissue, removed from the orbit, and also in histological sections. Culture of the tissue was positive for fungus which was resistant to cycloheximide (0.5 g/l). It was identified as Paecilomyces lilacinus (Thom) Samson (IMI 213487) and shown to be pathogenic for the rabbit cornea.

Adult

Mycotic keratitis due to Rhizoctonia sp.

A case of mycotic keratitis due to Rhizoctonia sp. is reported for the first time. Fungal hyphae were detected in corneal scrapings and cultures were found positive for Rhizoctonia sp. on two occasions. Species could not be identified and it has been disposed in Herb. IMI as Rhizoctonia sp. (IMI 200029). The isolate grew faster at 37 degrees C than at 28 degrees C and its pathogenicity was established in rabbit's eye.

Animals

Evaluation of the cell-mediated immune response of chickens vaccinated with Newcastle disease virus as determined by the under-agarose leukocyte-migration-inhibition technique.

The under-agarose leukocyte-migration-inhibition (LMI) assay for the evaluation of cell-mediated immunity (CMI) was developed for use in chickens. A significant CMI response was demonstrated in chickens vaccinated with Newcastle disease vaccine by using this assay. Results also indicated that the under-agarose LMI test was a reproducible and relatively easy assay to perform. Serologic antibody titers were determined to study the correlation between hemagglutination-inhibition (HI) titers and LMI levels using the HI microassay. The presence of the CMI response always correlated to the presence of the serologic immune response and vice versa. However, the quantitative level of the CMI response did not always correspond to the quantitative level of the serologic immune response. Going by results of this study, we were unable to predict humoral antibody level on the basis of a CMI response and vice versa.

Animals