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Biomedical subjects

G R Rao

Publications and source records attributed to G R Rao.

At least 19 recordsLinked to original sources
PubMed2004

Right prosubiculum amyloid plaque density correlates with anosognosia in Alzheimer's disease.

BACKGROUND: Anosognosia is a common manifestation of Alzheimer's disease. There is an association between impaired awareness and frontal-executive cognitive deficits. Anosognosia is also correlated with decreased metabolism in the right hemisphere, particularly in frontal lobe regions. OBJECTIVE: To investigate pathological correlates of anosognosia in Alzheimer's disease. DESIGN: 41 subjects followed longitudinally in the University of Pittsburgh memory disorders clinic and with necropsy verified Alzheimer's disease were divided into two groups, based on previous clinical assessment: +Aware (n = 23) and -Aware (n = 18). A subset analysis matching subjects for dementia severity using mini-mental state examination scores was also carried out (13 +Aware; 13 -Aware). Histopathological data from necropsy brain tissue consisted of senile plaque (SP) and neurofibrillary tangle (NFT) counts (regional density) from four different brain regions in the right and left hemispheres: superior and middle frontal gyri (SMF), superior temporal isocortex (ST), the prosubiculum of the hippocampus (PRO), and the entorhinal cortex (EC). RESULTS: SP density was greater in the right PRO region of -Aware subjects (F = 6.54, p = 0.015) than +Aware subjects. Significant differences between SP or NFT density were not observed in any other regions. In the subset analysis matching for dementia severity, SP density was again greater in the right PRO region of -Aware subjects than in the other regions (F = 12.72, p = 0.002). CONCLUSIONS: Increased SP density in the right PRO region suggests that selective pathological involvement of this area contributes to awareness deficits in Alzheimer's disease. The putative role of the PRO in self appraisal may reflect its interconnections with other medial temporal and prefrontal regions.

Aged↗
PubMed1997

Vibrational analysis of substituted benzonitriles. I. Vibrational spectra, normal coordinate analysis and transferability of force constants of monohalogenated benzonitriles.

The Raman and Fourier--transform infrared spectra of p- and o-fluorobenzonitriles, p-, m- and o-chlorobenzonitriles and p-, m- and o-bromobenzonitriles were measured. Raman polarisation measurements were made wherever possible. A normal coordinate analysis was carried out for both the in-plane and out-of-plane vibrations of these molecules along with m-fluorobenzonitrile using a 71-parameter modified valence force field. An overlay least-squares-technique was employed to refine the force constants using 269 frequencies of nine molecules. The reliability of the force constants so obtained was tested by making a zero-order calculation for both in-plane and out-of-plane vibrations of p-, m- o-dicyanobenzenes and their deuterated isomers; 2-chloro, 6-fluorobenzonitrile, s-trichlorobenzonitrile, p- and m-methoxybenzonitriles and m-nitrobenzonitrile; and for the in-plane vibrations of p-, m-, o-aminobenzonitrile and 2-chloro, 5-aminobenzonitrile. Unambiguous vibrational assignments of all the fundamentals were made using the potential energy distributions and eigenvectors.

Halogens↗
PubMed1997

Vibrational analysis of substituted benzonitriles. II. Transferability of force constants--the case of dicyanobenzenes.

A zero-order normal coordinate analysis was made for p-, m- and o-dicyanobenzenes and their deuterated isomers by transferring the force constants from Part I. The observed and calculated frequencies agree with an average error of 18.7 cm-1, demonstrating the transferability of the force field obtained in Part 1. On the basis of the calculated potential energy distributions and eigen vectors, several assignments suggested by earlier workers have been revised.

Models, Chemical↗
PubMed1997

Vibrational analysis of substituted benzonitriles. IV. Transferability of force constants--the case of some aminobenzonitriles.

A zero-order normal coordinate analysis was made for the n-plane vibrations of p-, m- and o-aminobenzonitrile and 2-chloro, 5-aminobenzonitrile by transferring the force constants from our earlier work. The observed and calculated frequencies agree with an average error of 19.3 cm-1. Unambiguous vibrational assignments of in-plane fundamentals of the four molecules have been made, and several assignments suggested by earlier workers have been revised.

Models, Chemical↗
PubMed1997

Vibrational analysis of substituted benzonitriles. III. Transferability of force constants--the case of some halogeno-, methoxy- and nitro-benzonitriles.

A zero-order normal coordinate analysis of both the in-plane and out-of-plane vibrations was made for 2-chloro, 6-fluorobenzonitrile, s-trichlorobenzonitrile, p- and m-methoxybenzonitriles and m-nitrobenzonitrile, transferring the force constants from our earlier work. The observed and calculated frequencies agree with an average error of 16.8 cm-1, demonstrating the transferability of the force constants obtained previously. On the basis of calculated potential energy distributions and eigenvectors, several assignments suggested by earlier workers have been revised.

Anisoles↗
PubMed1997

A novel autophosphorylation mediated regulation of nitrite reductase in Candida utilis.

The assimilatory nitrite reductase catalyses the conversion of nitrite to ammonia. The enzyme from Candida utilis has been previously purified to homogeneity and shown to be a heterodimer consisting of 58 kDa and 66 kDa subunits. The enzyme has also been shown to be induced by nitrate and repressed by ammonium ions. The levels of nitrite reductase mRNA, its protein and the enzyme activity were modulated together indicating that the primary level of regulation of this enzyme existed at the transcriptional level. Here we report that the 58 kDa and 66 kDa subunits of the enzyme were differentially phosphorylated under the induced and repressed conditions, indicating a second level of regulation. The highly phosphorylated 66 kDa subunit was shown to be dephosphorylated by calf intestinal alkaline phosphatase. The enzymatic activity associated with the native enzyme also decreased due to the dephosphorylation. Each of the subunits could undergo autophosphorylation at serine/threonine residues as demonstrated by thin layer chromatography and recognition by antibodies to phosphoamino acids. The presence of similar phosphorylated subunits under in vivo conditions has also been demonstrated. A model has been proposed to explain the post-translational regulation of the enzyme.

Amino Acids↗
PubMed1996

Purification and characterization of assimilatory nitrite reductase from Candida utilis.

Nitrate assimilation in many plants, algae, yeasts and bacteria is mediated by two enzymes, nitrate reductase (EC 1.6.6.2) and nitrite reductase (EC 1.7.7.1). They catalyse the stepwise reduction of nitrate to nitrite and nitrite to ammonia respectively. The nitrite reductase from an industrially important yeast, Candida utilis, has been purified to homogeneity. Purified nitrite reductase is a heterodimer and the molecular masses of the two subunits are 58 and 66 kDa. The native enzyme exhibits a molecular mass of 126 kDa as analysed by gel filtration. The identify of the two subunits of nitrite reductase was confirmed by immunoblotting using antibody for Cucurbita pepo leaf nitrite reductase. The presence of two different sized transcripts coding for the two subunits was confirmed by (a) in vitro translation of mRNA from nitrate-induced C. utilis followed by immunoprecipitation of the in vitro translated products with heterologous nitrite reductase antibody and (b) Northern-blot analysis. The 66 kDa subunit is acidic in nature which is probably due to its phosphorylated status. The enzyme is stable over a range of temperatures. Both subunits can catalyse nitrite reduction, and the reconstituted enzyme, at a higher protein concentration, shows an activity similar to that of the purified enzyme. Each of these subunits has been shown to contain a few unique peptides in addition to a large number of common peptides. Reduced Methyl Viologen has been found to be as effective an electron donor as NADPH in the catalytic process, a phenomenon not commonly seen for nitrite reductases from other systems.

Candida↗
PubMed1996

HPV 16 DNA sequences in different grades of cervical lesions.

A simple rapid method for isolation of genomic DNA from cervical scrape cells has been standardized. Sufficient amount of good quality genomic DNA was isolated from each cervical scrape specimen. Total 120 cervical scrape specimens from wide spectrum of cervical lesions were analysed for the presence of HPV 16 DNA by Southern hybridization using 32P labelled HPV 16 DNA as probe under stringent conditions. Viral DNA sequences were detected in 78 of the specimens. About 36% (5 out of 14) of normal cervical smears and 59% (46 out of 78) of inflammatory cervical smears had the viral DNA sequences. Except a lone sample, the rest 27 samples of different grades of dysplasia specimens and squamous cell carcinoma samples had viral DNA sequences. Due to development of sensitive Southern hybridization method, the presence of HPV 16 DNA could be detected in high percentage of specimens belonging to the inflammatory cervical specimens.

DNA, Viral↗
PubMed1994

Stability of copper tolerance in Thiobacillus ferrooxidans.

A strain of Thiobacillus ferrooxidans MAL-4-1 was adapted to grow at higher concentrations of copper by repeated subculturing in the presence of increasing levels of added cupric ions in 9K medium. The strains adapted to copper were found to be more efficient in bioleaching of copper from concentrates. When copper tolerant strains were back cultured repeatedly in 9K medium without cupric ions, the initially developed metal tolerance was observed to be lost. This indicates that the copper tolerance developed is stress-dependent and not a permanent trait of the adapted strain.

Copper↗
PubMed1994

Studies on Cassia pollen grains of India.

The aerial distribution of the pollen grains Cassia species was found to be predominant in Kerala and Tamil Nadu, the adjacent states of South India. The present study deals with the allergenicity and biochemical aspects of four different species of Cassia which were found to be dominant in the atmosphere of India. The pollen grains of Cassia occidentalis were found to be the most and Cassia roxburghii the least reactive of the four different species studied. The individual analysis of the reactive patients also showed the possibilities of cross-reactivity. The protein, carbohydrate and amino acids of these members were analysed. The results obtained are useful as a step towards standardisation of allergen extracts of Cassia species and are also worthy of further investigations both in relation to cross-reactivity and characterisation of allergens.

Adolescent↗
PubMed1994

Accurate transcription initiation by RNA polymerase II from Candida utilis.

An in vitro transcription system from Candida utilis is described. The template used is a hybrid plasmid containing Saccharomyces cerevisiae CYC1 promoter linked to a synthetic 377-bp G-minus casette (1). In vitro transcriptions are carried out in the presence of RNase. T1. Under these conditions only the transcripts that are resistant to RNase T1 accumulate. Using this protocol, it has been shown that in the absence of cytosolic factors RNA polymerase II (pol II) from C. utilis initiated RNA synthesis randomly. But both C. utilis and S. cerevisiae cell-free extracts could direct pol II from C. utilis to initiate transcription accurately. Results also indicated that the general transcription factors are functionally interchangeable between S. cerevisiae and C. utilis.

Candida↗
PubMed1994

Superhelical density of goat mitochondrial DNA: fluorimetric studies.

EtBr binding to DNA has been used to determine the superhelical density of Goat mtDNA. The differential binding of closed circular and nicked circular DNA is estimated by simple fluorescence measurements, which is a function of state of DNA supercoiling. The method is simple and quick over the cesium chloride density gradient centrifugation studies.

Animals↗
PubMed1993

Surface Chemistry of Thiobacillus ferrooxidans Relevant to Adhesion on Mineral Surfaces.

Thiobacillus ferrooxidans cells grown on sulfur, pyrite, and chalcopyrite exhibit greater hydrophobicity than ferrous ion-grown cells. The isoelectric points of sulfur-, pyrite-, and chalcopyrite-grown cells were observed to be at a pH higher than that for ferrous ion-grown cells. Microbe-mineral interactions result in change in the surface chemistry of the organism as well as that of the minerals with which it has interacted. Sulfur, pyrite, and chalcopyrite after interaction with T. ferrooxidans exhibited a significant shift in their isoelectric points from the initial values exhibited by uninteracted minerals. With antibodies raised against sulfur-grown T. ferrooxidans, pyrite- and chalcopyrite-grown cells showed immunoreactivity, whereas ferrous ion-grown cells failed to do so. Fourier transform infrared spectroscopy of sulfur-grown cells suggested that a proteinaceous new cell surface appendage synthesized in mineral-grown cells brings about adhesion to the solid mineral substrates. Such an appendage was found to be absent in ferrous ion-grown cells as it is not required during growth in liquid substrates.

Journal Article↗
PubMed1991

Education, fertility and contraception among Hindus and Roman Catholics in Goa.

Differences in age at marriage, fertility and contraceptive use are related to religious background, individual educational level and community level education. In general, the effects of community education are weak compared to individual level of education, but differences exist between Hindus and Roman Catholics.

Adult↗