Search PubMed⌕ Search

Biomedical subjects

R Chandra

Publications and source records attributed to R Chandra.

At least 289 records · Page 16Linked to original sources
PubMedDate not supplied

In heme catabolism C2 and C4 vinyl groups reduction of cobalt protoporphyrin forms cobalt mesoporphyrin and alters the nature of action of the metalloporphyrin in vivo.

Heme is a tetrapyrrolic ring with iron as the central metal atom and acts as a prosthetic group for a number of enzymes, e.g. cytochromes and globins. It also plays an important role in the regulation of transcription, translation, protein translocation and erythroid differentiation. Thus, heme regulation is under strict control in the body. Our studies on the regulatory enzymes of heme anabolism, aminolevulinic acid synthetase (ALA-S), and of catabolism, heme oxygenase (HMOX), in the spleen has revealed that cobalt protoporphyrin acts as an inducer of HMOX. It is revealed that by alteration of side groups at C2 and C4 changes the nature of action of Co-protoporphyrin from an inducer to a strong inhibitor of HMOX activity. All the three analogues Co-protoporphyrin, Co-mesoporphyrin and Co-hematoporphyrin have been shown to induce the ALA-S activity to the similar extent. NADPH-cytochrome c reductase, a microsomal membrane bound enzyme, is required by HMOX for the enzymatic conversion of heme into biliverdin IXc and is also required for NADPH-dependent lipid peroxidation in the microsomes. It has been observed that Co-mesoporphyrin causes an inhibition of HMOX activity and consequently leads to an induced level of microsomal NADPH-dependent lipid peroxidation.

5-Aminolevulinate Synthetase↗
PubMedDate not supplied

Co-administration of melatonin reverses the tin-protoporphyrin (SnPP) induced decline of cytochrome P450 content in vivo in rats.

Melatonin (N-acetyl-5 methoxytryptamine) is a low molecular weight antioxidant and is an endogeneous defense system against the deleterious actions of the extremely reactive hydroxyl radical. Among the enzymes that participate in the antioxidant functions is cytochrome P-450, a stalwart of the detoxification system in the body. Our results revealed that tin-protoporphyrin administration brought about a marked decline in cytochrome P-450 levels. This decline was, however, reversed by the coadministration of the antioxidant, melatonin. Thus, the enhanced antioxidant status in melatonin-treated rats may act as a protective mediator of various pharmacological functions altered during tin-protoporphyrin (an antihyperbilirubemenic agent) administration to Wistar rats.

5-Aminolevulinate Synthetase↗
PubMedDate not supplied

Anorectal function and continence mechanisms in childhood encopresis.

We compared anorectal sensory and motor functions, expulsion dynamics, and continence mechanisms in 50 children with encopresis and 21 healthy control children. When expulsion dynamics were studied, 43% of boys with encopresis inappropriately contracted the muscles near the anal canal compared with 10% of girls with encopresis (p greater than 0.05) and 10% of control children of both sexes (p less than 0.05). In contrast to previous studies we demonstrated no abnormalities of thresholds of conscious rectal sensation or internal anal sphincter relaxation. In addition, children with encopresis had no demonstrable abnormalities of rectosphincteric continence mechanisms or strength of external anal sphincter contraction. We conclude that a significant number of boys with encopresis have abnormal anorectal expulsion dynamics, which may contribute to chronic fecal retention and incontinence. Abnormalities of anorectal sensory and motor function and of rectosphincteric continence mechanisms do not seem to be important in the pathogenesis of childhood encopresis.

Adolescent↗
PubMedDate not supplied

Evaluation of biofeedback in childhood encopresis.

In order to evaluate the efficacy of biofeedback for childhood encopresis, 50 children with encopresis were prospectively studied and randomized to receive biofeedback (B) or mineral oil therapy (M). Specificity of biofeedback was also evaluated by comparing outcomes of both regimens in children with normal (n = 32) and abnormal (n = 18) defecation patterns. Using a single blinded design, there were no significant differences in clinical outcomes between the 24 children receiving B and the 26 children receiving M at 3, 6, and 12 months. However, at 12 months six of nine children with abnormal defecation patterns were in remission or markedly improved after receiving B, compared to only three of nine children receiving M. In contrast, children with normal patterns appeared to respond better to M than did those receiving B (71 vs. 40% at 12 months). Biofeedback appears to warrant further evaluation in children with encopresis and abnormal defecation patterns.

Adolescent↗
PubMedDate not supplied

Long term study of random noise and signal uniformity in spin-echo brain imaging.

Random noise and MR signal uniformity were analyzed for a period of 9 months using two head coils on a 1.5 T commercial imager. Signal response from a cylindrical phantom filled with a 0.1 mmol/L CuSO4 solution was incorporated in a correction scheme and the effect of correction on uniformity and accuracy of tissue volume determination was measured. There was little change in random noise (CV < 5%) and image uniformity (CV < 15%) over the time of the study. The uniformity in a 130 cm2 region was 4% for a double saddle coil and 5.3% for a mirror coil. After correction, uniformity was improved to 1.1% for the double saddle coil and 1.2% for the mirror coil. In a 40 cm2 central region the uniformity was approximately three times better than in the 130 cm2 region. A second phantom, mimicking the relaxation times of CSF and the brain, consisted of saline encapsulated in vials of volume ranging from 35.6 ml to 249.6 ml and placed in a 0.1 mmol/L solution of MnCl2. Uniformity correction reduced the average error in volume measurement from 8.6% to 6.1%.

Adult↗
PubMedDate not supplied

AIDS awareness amongst school teachers in a rural area of India.

One hundred and eighty-two teachers from a random selection of 15 schools in a rural area of Lucknow district of northern India were interviewed to assess their awareness and knowledge about AIDS using a pretested CARC proposed questionnaire. Observations revealed that only 79.7% of the teachers had heard about AIDS, newspapers being the main source of information. Awareness amongst graduate teachers was significantly higher than non-graduates. Many believed AIDS to be mosquito-borne and less than 2% knew that condom usage make sex safer. The study reveals the need to undertake intensive health education efforts as school teachers are an important source of health-related information for rural populations.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Impact of Urban Basic Services on immunization coverage in a slum area of northern India.

The Urban Basic Services (UBS) programme was launched in some of the urban slums in the major cities of India in the year 1986. The main objective of the Urban Basic Services (UBS) Program is to improve and upgrade the quality of life of the urban poor, particularly the women and children. The major thrust area under the UBS programme includes child survival and development, learning opportunities for women and children, water and sanitation, and community organization. The present study attempts to find out the impact of the UBS Program in terms of the immunization coverage carried out in slums covered by UBS and comparing it with non-UBS slums using the 30-cluster sampling technique as suggested by WHO. The percentage of fully immunized children was higher (16.2%) in the UBS slums compared to 10.9% in non-UBS slums. The immunization coverage of children was slightly better in the UBS slums for BCG, DPT and Oral Polio Vaccines, while for measles it was 18.6% in UBS slums and 11.9% in non-UBS slums. The dropout rates for I to III doses of DPT was much higher (36.4%) in non-UBS slums as compared to 28% in UBS slums. The availability of immunization cards was found to be higher in both mothers (16.7%) and children (22.4%) in UBS slums compared to the non-UBS ones (5.2% and 8.6% respectively). The slums thus covered under the UBS program have done marginally better in immunization but it appears that to assess the overall impact of UBS, all the components of services and not merely immunization should be assessed.

Child↗
PubMedDate not supplied

Can beta-hydroxybutyrate be detected at the bedside by in vitro oxidation with hydrogen peroxide.

The diagnosis of ketoacidosis with an inordinately high plasma and urinary concentration ratio of beta-hydroxybutyrate (beta-OHB) to acetoacetate (AcAc) is difficult, because only AcAc and acetone react with the diagnostic reagents used clinically to detect ketones. The purpose of this study was to assess the validity of the claim that beta-OHB can be identified with a simple modification of the usual bedside test for ketones, using hydrogen peroxide (H2O2) and Ketostix (Ames Division, Miles Laboratories, Inc., Elkhart, Indiana). Unfortunately, the lowest detectable concentration of urinary beta-OHB was 50 mmol/L, and serum beta-OHB could not be detected at levels less than 100 mmol/L, a clinically irrelevant level. The relative insensitivity, the inapplicability to serum, and the potential hazard of the routine use of 30% H2O2 by practicing physicians or houseofficers render the method of limited value.

3-Hydroxybutyric Acid↗
PubMedDate not supplied

A familial syndrome of growth retardation, severe Fanconi-type renal disease and glomerular changes--a new entity?

Two young siblings had a syndrome of growth retardation, severe rickets, anemia, renal insufficiency, and renal tubular dysfunction, the last including acidosis, aminoaciduria, and polyuria. There was moderate psychomotor developmental delay. Neither child had cystinosis. Renal biopsy in the older child revealed severe glomerular abnormalities, with capillary wall thickening reminiscent of the hemolytic-uremic syndrome. The proximal convoluted tubules were lined with short, cuboidal cells containing mildly abnormal mitochondria. There was also thinning of brush border microvilli and basolateral infoldings, perhaps as the result of regressive changes, and interstitial fibrous tissue was moderately increased. The etiology of the tubular and glomerular changes is uncertain. We believe these patients represent a previously unreported hereditary syndrome sharing certain clinical features with severe nephropathic cystinosis.

Child, Preschool↗
PubMedDate not supplied

Evolution of membranous nephropathy from a proliferative and exudative glomerulonephritis--a report of three cases studied by serial biopsies.

Three adolescents with clinical nephrotic-nephritic picture were noted to have diffuse proliferative and exudative glomerulonephritis. Although focal membranous changes were noted in two of the initial biopsies, evolution into classical membranous glomerulopathy was seen in subsequent biopsies. This study suggests a relationship between these two different patterns of immune complex-associated glomerular injury, and confirms extrapolations made from experimental models of chronic serum sickness.

Biopsy↗