Search PubMed⌕ Search

Biomedical subjects

A Sharma

Publications and source records attributed to A Sharma.

At least 721 records · Page 40Linked to original sources
PubMed1992

The blood group and haemoglobin types of the Santals.

A total of 488 blood samples from tribal as well as non-tribal donors of Bihar and West Bengal were analysed for presence of abnormal haemoglobin variants. Out of 488 samples ABO and Rh blood groups were studied in 468 samples. Predominance of group B was noted in both the tribal and non-tribal groups and absence of Rh(d) was noted in non-tribal population with the exception of the tribals where 4.42% Rh(d) gene was found. Incidence of haemoglobin E gene was very low in most cases but relatively higher in non-tribal populations, while the range of raised haemoglobin A2 varied from 5.84% to 8.80%.

ABO Blood-Group System↗
PubMed1992

Identification of a 10-base pair protein binding site in the promoter of the hamster H3.2 gene required for the S phase dependent increase in transcription and its interaction with a Jun-like nuclear factor.

The hamster histone H3.2 promoter contains an AP-1-like element (referred to as site X) that contains the sequence CGAGTCA. This site differs from the Jun/AP-1 consensus sequence by one base and is also similar to the cyclic AMP response element. Similar AP-1/cyclic AMP response element-like sites have been found in the promoters of other histone H3 genes and are known to bind proteins either in vivo or in vitro. Using site directed mutagenesis, we demonstrate that a 10-base pair region which encompasses site X is a positive control element that is necessary for the S phase dependent increase in H3.2 transcription in cells synchronized by serum stimulation or aphidicolin block. DNase I footprint analysis shows that mutating site X eliminates v-Jun and hamster cellular factor(s) binding. Further in vitro analysis with gel retardation assays reveals that the flanking sequence of this site is necessary for the formation of an H3.2 specific complex that can be distinguished from complexes formed with a collagenase or SV40 AP-1 element. Antibodies specific to the different members of the Jun and Fos family of transcription factors show that, in gel retardation assays, a Jun-like factor is a component of the H3.2 specific complex. However, the H3.2 specific complex exhibits different reactivity toward the Jun and Fos specific antibodies as compared to complexes formed with a collagenase AP-1 element. We hypothesize that a unique protein complex, containing a component related to the AP-1 family of transcription factors, binds to the AP-1-like motif of the hamster H3.2 promoter and may be involved in the S phase dependent regulation of transcription.

Animals↗
PubMed1992

Cytotoxic effects of Sumicidin, a type II synthetic pyrethroid, on mice in vivo at 6, 12 and 24 h after exposure.

The ability of Sumicidin, a synthetic pyrethroid, to induce cytotoxicity in Swiss albino mice was evaluated before completion of the first cell division following oral exposure. Mice were administered orally different concentrations (32.50, 75 and 150 mg/kg body wt) of Sumicidin in a single dose. Mitotic index and chromosomal aberrations were screened after 6, 12 and 24 h following exposure. The frequency of dividing cells decreased significantly, indicating mitostatic action. The frequency of chromosomal aberrations was directly related to the concentrations used and the duration after exposure, and was significant at all concentrations. The highest frequency of aberrations was observed 24 h after exposure.

Animals↗
PubMed1992

Nutritional status of children of urban leprosy patients staying at preventoria based on biochemical parameters.

Measurements of nutritionally relevant biochemical and endocrine variables were made on 60 apparently healthy children (group A) whose parents suffered from leprosy and who had been separated at the age of 4 years and brought up in preventoria. Most of the measurements were also made on a comparison group of healthy children from the same poor socio-economic class (group B). In both groups the serum concentrations of cholesterol and triglycerides were well below those found in Western populations. Almost all the children in both groups were anaemic, but serum iron and ferritin levels were satisfactory. Folate and vitamin B12 levels were measured in group A only and were low in a significant proportion. Deficiency of these water-soluble vitamins may be a cause of the anaemia. Low albumin levels were found in 40% of group A children, compared with 2% in group B. The concentrations of calcium and magnesium were lower and that of phosphate higher in group A than in B. In both groups one-third of the children had low levels of serum zinc. Fifteen per cent of group A children had biochemical evidence of vitamin A deficiency, but none were deficient in vitamin E. Levels of total T3 and total T4 were below the lower limit of normal in a substantial proportion of children in both groups. Concentrations of parathyroid hormone were increased in parallel with the low values for serum calcium. Radiological studies of ossification centres in 57 group A children showed delayed maturation in 11 cases. The relevance of these findings to previous studies of the children of lepers in India is discussed.

Adolescent↗
PubMed1992

Chronic corneal perforations.

We report the etiological profile and management with simple patch, tarsorrhaphies, conjunctival flaps, tissue adhesive, or penetrating keratoplasty of 104 chronic corneal perforations in a North India population. Chronic corneal perforations were observed in infective keratitis, degenerative keratolysis, neurotrophic keratitis, chemical burns, dry eyes, collagen vascular diseases, and following cataract extraction. A two-stage tissue adhesive application and adhesive-assisted debridement of epithelial lining at the cornea surface of perforation were important factors in healing. Although penetrating keratoplasties brought comparable anatomical and functional success in these cases, in developing countries, where facilities for keratoplasty and availability of corneal donor is poor, detection and management of small perforations in diseased cornea with tissue adhesive is recommended.

Adolescent↗
PubMed1992

Oral aluminium phosphide poisoning in Indian children.

Aluminium phosphide, due to its low cost, easy availability and highly toxic nature, is emerging as a common self-poisoning agent in adults. In children, besides accidental ingestion, it is usually given by their parents who themselves have taken it with suicidal intentions. Seven such cases in children are reported. Since prevention is the only logical approach there is an urgent need to take appropriate steps to prevent further loss of lives.

Adolescent↗
PubMed1992

Measurement of ventricular size in term and preterm infants.

Real time ultrasonography was done in neonates to establish the norms for ventricular size and to see if there is a correlation between ventricle size and gestational age. A total of 153 normal infants admitted to our nursery after September, 1989 were taken up for the study. First ultrasound was performed within six days of birth. Sonography was done with 3.5 MHz transducer through anterior and lateral fontanelle. Results revealed that there is a significant difference in the mean value of falx to lateral wall of the cortex, ventricular index and ratio (VI/FC) of preterm and term infants. The ventricular size of small for gestational age infants is significantly different from appropriate gestational age infant of corresponding gestational ages. The percentile chart of VI for Indian infants is comparable to that of western infants.

Anthropometry↗
PubMed1991

Synthesis, isolation, and characterization of endogenous beta-galactoside-binding lectins in human leukocytes.

Galaptin, a beta-galactoside-binding lectin, was isolated from human buffy coat cells (peripheral leukocytes) and spleen by affinity chromatography. The molecular weight (32K) of the native buffy coat galaptin was similar to that for splenic galaptin. Their subunit molecular weight (14.5K), pI (4.60-4.85), and amino acid composition were identical. Both galaptins showed the presence of a single polypeptide when subjected to reversed-phase HPLC. Monospecific rabbit polyclonal antiserum raised against the 14.5-kDa subunit of splenic galaptin reacted with a 14.5-kDa polypeptide present in buffy coat cells, Epstein-Barr virus-immortalized B lymphoblastoid cells, and HL-60 promyelocytic leukemia cells. However, galaptin was not synthesized in vitro by buffy coat cells. Rather, a monomeric beta-galactoside-binding protein of Mr 15.5-16.5K that is immunologically distinct from galaptin was synthesized. This galactoside-binding protein was separable from galaptin by polyacrylamide gel electrophoresis and by anion-exchange chromatography. In contrast, immunoprecipitation experiments confirmed that galaptin was synthesized by the B lymphoblastoid cells. cDNA corresponding to the B lymphoblastoid cell mRNA encoding galaptin was amplified by the polymerase chain reaction. The amplified product was partially sequenced, and 299 nucleotides were identified. The derived amino acids corresponded to residues 6-65, 84-114, and 118-126 found to be present in human splenic galaptin. Immunohistochemical analyses revealed that galaptin was distributed throughout the cytoplasm of B lymphoblastoid cells rather than being localized to the cell surface.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1991

Modifying role of Phyllanthus emblica and ascorbic acid against nickel clastogenicity in mice.

Nickel, a major environmental pollutant is known for its clastogenic and carcinogenic potential. Dietary inhibitors of mutagenesis and carcinogenesis are of particular importance since they may have a role in cancer prevention. In the present investigation, aqueous extract of edible dried fruits of Phyllanthus emblica, a well known medicinal plant, was fed to Mus musculus for seven consecutive days prior to treatment with different doses of nickel chloride (10, 20 and 40 mg/kg body wt.); the fruit extract significantly reduced the frequency of CA/cell, the percentage of aberrant cells and the frequency of micronuclei induced by all doses of nickel in the bone marrow cells of mice. Ascorbic acid, a major constituent of the fruit, fed for 7 consecutive days in equivalent concentration as that present in the fruit, however, could only alleviate the cytotoxic effects induced by low doses of nickel; at the higher doses it was ineffective. The greater efficacy of the fruit extract could be due to the interaction of its various natural components rather than to any single constituent. The study assumes importance in view of the widespread human exposure to nickel compounds.

Animals↗
PubMed1991

Use of a digital brain atlas to compare the distribution of NGF- and bFGF-protected cholinergic neurons.

The effectiveness of basic fibroblast growth factor and nerve growth factor in preventing the lesion-induced disappearance of septal cholinergic neurons was compared by using a computerized data-acquisition system and a digital brain atlas that yielded quantitative and distributional information. Adult rats were given unilateral partial transections of the fimbria and then received daily intraventricular injection of one of the growth factors for 15 days. Given the high degree of co-localization of nerve growth factor receptors with choline acetyltransferase in these areas, cholinergic neurons were identified by nerve growth factor receptor immunoreactivity. Their locations were plotted in the context of a three-dimensional brain atlas permitting the analysis of relative distributions of cholinergic neurons in control brains and those of animals treated with each growth factor. The cholinergic cell disappearance induced by the partial fimbrial transection was restricted to the medial septal nucleus and the vertical limb of the diagonal band of Broca. Within the affected areas cholinergic cell disappearance increased gradually in severity from anterior to posterior levels of the septal nucleus. Both growth factors prevented the disappearance of cholinergic cell bodies in medial septal nucleus and vertical limb of the diagonal band. In lesioned control animals the unilateral cell disappearance amounted to 53.5% of the number of cholinergic neurons of the unlesioned side. Nerve growth factor and basic fibroblast growth factor reduced this disappearance to 13% and 28%, respectively. The distribution of cholinergic cells was the same in animal treated with each growth factor, suggesting that the two growth factors protect the same population of cholinergic neurons.

Brain↗
PubMed1991

Synthesis and carbohydrate-binding activity of poly(ethyleneglycol)-Ricinus communis agglutinin I conjugates.

The synthesis of poly(ethyleneglycol) (PEG)-lectin conjugates was investigated to provide new reagents for evaluation as biological response modifiers. PEG was activated with 1,1'-carbonyldiimidazole (CDI), followed by conjugation with Ricinus communis I (RCAI) lectin. The resulting conjugates were heterodisperse with respect to molecular weight. Carbohydrate-binding activity was retained. The conjugates were separated by affinity chromatography into fractions differing in apparent carbohydrate-binding affinity. Conjugation of RCAI with PEG 4 (mol.wt. 3350) or PEG 6 (mol.wt. 8000) appeared to provide less hindrance of the lectin binding site compared to conjugates prepared with PEG 20 (mol.wt. 20,000). Results of free amine assays indicated that higher ratios of PEG to RCAI in conjugates correlated with loss of low-affinity binding and retention of high-affinity binding. The data showed the feasibility of preparing PEG-lectin conjugates for in vivo use.

Binding Sites↗
PubMed1991

Lipoprotein-cyclodextrin interaction.

Interaction of cyclodextrins with native and isolated lipoproteins was studied by electrophoretic and spectroscopic means. Reaction between these two biomolecules resulted in the formation of soluble and insoluble complexes. Cyclodextrin-mediated precipitation of lipoproteins was strongly affected by the concentration of the oligosaccharide and the presence of guest molecules capable of being entrapped within the cyclodextrin cavity. Lipoprotein precipitation by cyclodextrins was observed under acidic, neutral as well as alkaline conditions. The ionic strength of the medium did not significantly affect this interaction. Under appropriate experimental conditions, most types of cyclodextrins were able to form complexes with the various lipoprotein classes. The ability of cyclodextrins to precipitate lipoproteins was in the order of beta-cyclodextrin greater than alpha-cyclodextrin greater than gamma-cyclodextrin and hydroxyalkylated beta-cyclodextrin. Among the lipoproteins, the order of reactivity with a given cyclodextrin was: low density lipoproteins greater than high density lipoproteins greater than very low density lipoproteins. Competitive studies using L-phenylalanine and methanol, both of which form inclusion complexes with cyclodextrins, reveal that molecular encapsulation plays an important role in the stabilization of beta-cyclodextrin-lipoprotein complexes. The present data also suggests that the binding of cyclodextrins to lipoproteins may involve the formation of exclusion complexes.

Binding, Competitive↗
PubMed1991

Karyotype studies of patients with gonadal tumors.

Chromosomes from the peripheral blood of 10 patients with gonadal tumors were studied to detect any inherent chromosomal defect. Aneuploidy, breakages and loss of chromosome X were observed. In all cases the karyotype was compatible with the phenotype.

Adenocarcinoma, Mucinous↗
PubMed1991

The Bradyrhizobium japonicum nolA gene and its involvement in the genotype-specific nodulation of soybeans.

Several soybean genotypes have been identified which specifically exclude nodulation by members of Bradyrhizobium japonicum serocluster 123. We have identified and sequenced a DNA region from B. japonicum strain USDA 110 which is involved in genotype-specific nodulation of soybeans. This 2.3-kilobase region, cloned in pMJS12, allows B. japonicum serocluster 123 isolates to form nodules on plants of serogroup 123-restricting genotypes. The nodules, however, were ineffective for symbiotic nitrogen fixation. The nodulation-complementing region is located approximately 590 base pairs transcriptionally downstream from nodD2. The 5' end of pMJS12 contains a putative open reading frame (ORF) of 710 base pairs, termed nolA. Transposon Tn3-HoHo mutations only within the ORF abolished nodulation complementation. The N terminus of the predicted nolA gene product has strong similarity with the N terminus of MerR, the regulator of mercury resistance genes. Translational lacZ fusion experiments indicated that nolA was moderately induced by soybean seed extract and the isoflavone genistein. Restriction fragments that hybridize to pMJS12 were detected in genomic DNAs from both nodulation-restricted and -unrestricted strains.

Amino Acid Sequence↗
PubMed1991

Extracapsular cataract extraction in Nepal. 2-year outcome.

We evaluated the 2-year outcome of extracapsular cataract surgery with posterior chamber intraocular lens insertion by a single fellowship-trained surgeon in Kathmandu, Nepal. Six hundred ten eyes were followed up for 2 years. Patients underwent manual irrigation and aspiration with the insertion of a modified J loop posterior chamber intraocular lens. Almost half of the patients had uncorrected visual acuities of 20/50 or better after surgery. Sight-threatening complications in seven eyes (1.2%) included retinal detachment, corneal decompensation, and endophthalmitis. Although this rate is comparable to that in developed countries, 21% of patients had posterior capsular opacification at follow-up. Extracapsular cataract surgery with intraocular lens insertion may be an alternative to intracapsular cataract surgery in developing nations, where aphakic spectacles are expensive, not easily obtainable, or difficult to replace.

Aged↗