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Biomedical subjects

R Chaudhary

Publications and source records attributed to R Chaudhary.

At least 37 records · Page 2Linked to original sources
PubMed1998

Microdissection of pig chromosomes: dissection of whole chromosomes, arms and bands for construction of paints and libraries.

Chromosome microdissection is an important means to efficiently generate a large number of markers from a desired region of a genome. The present study was designed to initiate microdissection and amplification of DNA from whole chromosomes, arms, or bands of porcine chromosomes. The following pig (SSC) chromosomes/segments were scraped: SSC1p, SSC1q26-q2.13, SSC2q11-q14, SSC4q12-q25, SSC13, SSC13q12-q31, SSC13q32-q43, SSC13q32-q43, SSC15, and SSC16q21-q23. After amplification and PCR-labelling, the DNA from the dissected segments were painted back to normal metaphase chromosomes to test their identity. Microdissection of some of the segments (on SSC4, 13 and 15) coincides with the mapping of economically important traits. As a first step towards generation of markers, microcloning of amplified product from SSC1p and SSC15 was carried out. The libraries were screened with a (GT)15 oligonucleotide probe. Future prospects of such a work in farm animals are discussed.

Animals↗
PubMed1998

Comparison of six sets of PCR primers from two different genomic regions for amplification of GB virus C/hepatitis G virus RNA.

Forty-four clinical samples positive for GB virus C (GBV-C)/hepatitis G virus (HGV) were tested with six primer sets, four from the 5' untranslated region (5'-UTR) and two from the NS5a genomic region. Two of the 5'-UTR primer sets, when used in a single-round 60-cycle PCR, detected between 86.4 and 97.7% of the positive samples, while two different sets from the same area, when used in a nested PCR, amplified between 97.7 and 100% of the positive specimens. Both sets from the NS5a region, when used in a single-round PCR, detected 95.5% of the GBV-C/HGV-positive samples. Parallel testing with two PCR sets, one from the 5'-UTR and a second from NS5a, may eliminate false-negative results attributable to the genetic heterogeneity of the virus.

DNA Primers↗
PubMed1997

Transforaminal and posterior decompressions of the lumbar spine. A comparative study of stability and intervertebral foramen area.

STUDY DESIGN: Ten fresh, cadaveric, two-vertebrae, functional spinal units were used to study the pathoanatomy, intervertebral foraminal area, and flexibility changes after posterior and transforaminal decompression. OBJECTIVES: To determine the feasibility of an endoscopic transforaminal approach as an alternative to conventional approaches, to establish the adequacy of transforaminal decompression without destabilizing the spine, and to study the structural changes in the spine after decompressions. SUMMARY OF THE BACKGROUND DATA: Posterior decompression entails major dissection and excision of bone and ligaments to access the spinal canal. Posterior decompression may be complicated by acute or chronic spinal instability, and the adequacy of lateral decompression is highly subjective. METHODS: The functional spinal units were mounted in quick-setting epoxy blocks. Pre- and postoperative computed tomography scans were taken to study changes in the foraminal area. Pre- and postoperative flexibility and anatomic studies were performed to compare the results. RESULTS: A 45.5% increase in the intervertebral foraminal area was possible, there was no flexibility change, and minimal anatomic damage to the spine was noted after transforaminal decompression. A 34.2% increase in the intervertebral foraminal area and a significant increase in extension and axial rotation flexibility were noted after the posterior decompression. CONCLUSION: Transforaminal decompression produced a significantly larger increase in the intervertebral foraminal area than posterior decompression, without increasing the range of motion or neutral zone in any direction. Because there was no violation of the anatomic integrity of the spine in the transforaminal approach, the risk of surgically induced instability was minimized. Endoscopic transforaminal decompression is a feasible alternative to current approaches.

Adult↗
PubMed1997

FISH mapping of seven cDNA sequences in the pig.

Fluorescence in situ hybridization (FISH) technique was applied to localize seven clones derived from a porcine (SSC) intestinal directionally cloned cDNA library. The size of the clones ranged from 1.1 to 1.3 kb. Three of the clones corresponded to histidyl-tRNA synthetase (HARS), immunoglobulin alpha (IGA) and lysozyme (LYZ) and mapped to SSC2q28-q29, 7q2.6 and 5p11 respectively. The available human-pig comparative painting data and sequence homology comparisons assisted in a tentative identification of the other three clones as glutathione-S-transferase (GST), glutathione-S-transferase mu (GSTM1) and immunoglobulin lambda gene cluster (IGL@). These clones mapped to SSC14q21, 5q2.4 and 14q22-q23 respectively. The remaining clone representing an EST mapped to 1p24-p25. These localizations contribute to the transcript map in pig and are significant as comparative markers. Difficulties associated with the mapping of small sequences using FISH are discussed.

Animals↗
PubMed1996

Pigs with the dominant white coat color phenotype carry a duplication of the KIT gene encoding the mast/stem cell growth factor receptor.

Comparative mapping data suggested that the dominant white coat color in pigs may be due to a mutation in KIT which encodes the mast/stem cell growth factor receptor. We report here that dominant white pigs lack melanocytes in the skin, as would be anticipated for a KIT mutation. We found a complete association between the dominant white mutation and a duplication of the KIT gene, or part of it, in samples of unrelated pigs representing six different breeds. The duplication was revealed by single strand conformation polymorphism (SSCP) analysis and subsequent sequence analysis showing that white pigs transmitted two nonallelic KIT sequences. Quantitative Southern blot and quantitative PCR analysis, as well as fluorescence in situ hybridization (FISH) analysis, confirmed the presence of a gene duplication in white pigs. FISH analyses showed that KIT and the very closely linked gene encoding the platelet-derived growth factor receptor (PDGFRA) are both located on the short arm of Chromosome (Chr) 8 at band 8p12. The result revealed an extremely low rate of recombination in the centromeric region of this chromosome, since the closely linked (0.5 cM) serum albumin (ALB) locus has previously been in situ mapped to the long arm (8q12). Pig Chr 8 shares extensive conserved synteny with human Chr 4, but the gene order is rearranged.

Animals↗
PubMed1995

Extensive mtDNA diversity in horses revealed by PCR-SSCP analysis.

The hypervariable D-loop region of mitochondrial DNA (mtDNA) was amplified with the polymerase chain reaction using total horse DNA samples. Analysis of single strand conformation polymorphism (SSCP) of denatured amplification products was carried out by native polyacrylamide (8%) gel electrophoresis followed by silver staining. As many as 15 distinct SSCP variants were revealed when screening a total of 78 maternally unrelated horses representing five different breeds. All breeds showed a high degree of polymorphism and the estimated probability (PImt) that two maternally unrelated individuals have, by chance, identical SSCP variants varied between 0.14 and 0.30. We detected no heteroplasmy or deviations from strict and stable maternal inheritance when examining four maternal lineages, each represented by six to eight horses, separated by up to five generations from a common ancestral mare. The study establishes a simple screening method for detecting equine mtDNA types, which can be applied for tracing maternal genealogies and for association studies.

Animals↗
PubMed1994

Effects of sarcoplasmic reticulum calcium pump inhibitors on vascular smooth muscle.

A dysfunctioning of Ca2+ pump ATPase in the sarcoplasmic reticulum in vascular smooth muscle has been proposed as a contributing factor for the development of genetic hypertension. In this study, we determined whether in vitro inhibition of the sarcoplasmic reticulum Ca2+ pump in vascular smooth muscle tissues and cultured cells isolated from aortas of spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats would elicit the known alterations of contractile function and cell growth. We found the following common vascular effects of thapsigargin and cyclopiazonic acid, which are known to be selective inhibitors of sarcoplasmic reticulum Ca(2+)-ATPase in a number of tissues including smooth muscle: (1) Both sarcoplasmic reticulum Ca2+ pump inhibitors diminished agonist-induced transient contraction in Ca(2+)-free medium (ie, contraction due to intracellular release of Ca2+) and enhanced nifedipine-sensitive contraction on readmission of Ca2+ (ie, Ca2+ influx via L-type channels); and (2) thapsigargin and cyclopiazonic acid inhibited the attachment of cultured aortic muscle cells to the substrate in a similar degree in both SHR and WKY cells, but SHR cells were more sensitive than WKY cells to the inhibition of cell proliferation by these two agents. The first effect may provide an explanation for several contractile abnormalities known to be associated with elevated cytosolic Ca2+ concentration, whereas the second effect suggests that elevation of cytosolic Ca2+ in aortic smooth muscle cells is not necessarily associated with or sufficient to account for the accelerated cellular proliferation in SHR. These results, however, further stress the functional importance of impairment of Ca2+ regulation in vascular smooth muscle cells in genetic hypertension.

Animals↗
PubMed1993

In situ hybridization mapping and restriction fragment length polymorphism analysis of the porcine albumin (ALB) and transferrin (TF) genes.

In situ hybridization analyses were conducted on porcine metaphase chromosomes using porcine liver albumin (ALB) and transferrin (TF) cDNA probes. The ALB gene was assigned to the q12 band of chromosome 8 and the TF gene to the q31 band of chromosome 13. For the latter, a statistically significant secondary peak was observed on the 6p15 band. However, the TF probe predominantly hybridized to the 13q31 band, indicating that this band is the most likely site of the TF gene. Since the TF gene belongs to linkage group V, this linkage group can now be assigned to chromosome 13. The TF and ALB probes were also used for restriction fragment length polymorphism (RFLP) analysis. A screening of 10 unrelated animals revealed TaqI RFLPs for both ALB and TF. Family studies indicated that the ALB and TF polymorphisms were controlled by three and two alleles, respectively.

Alleles↗
PubMed1993

Localization of the ceruloplasmin (CP) gene to the q32-q33 bands of chromosome 13 in pigs by in situ hybridization.

Ceruloplasmin (CP) is a copper-binding protein in vertebrate plasma. In the present study, the porcine ceruloplasmin gene was localized to the 13q32-q33 bands by in situ hybridization, using a human CP cDNA probe. This confirmed the localization of the porcine linkage group V to chromosome 13. The CP locus is closely linked to the transferrin locus in pigs. Their relative physical order on chromosome 13 is discussed. Comparisons are made with the order of these two loci in other mammalian species.

Animals↗
PubMed1993

The gene for bovine interferon gamma (IFNG) maps to the q22-q24 bands of chromosome 5 in cattle.

A approximately 700 bp bovine IFNG cDNA probe was used for the chromosomal localization of the IFNG gene in cattle using in situ hybridization technique. This locus has previously been assigned to chromosome 5 by analysis of a somatic cell hybrid panel. The in situ hybridization results obtained in the present study allow us to map the locus at the 5q22-q24 bands. Relative location of the IFNG gene and the class II cytokeratin and HOX3 gene clusters in cattle and humans is discussed.

Animals↗
PubMed1993

Mutational screening of the Wilms's tumour gene, WT1, in males with genital abnormalities.

Several lines of evidence suggest that the Wilms's tumour susceptibility gene, WT1, has an important role in genital as well as kidney development. WT1 is expressed in developing kidney and genital tissues. Furthermore, mutations in WT1 have been detected in patients with the Denys-Drash syndrome (DDS), which is characterised by nephropathy, genital abnormalities, and Wilms's tumour. It is possible that WT1 mutations may cause genital abnormalities in the absence of kidney dysfunction. We tested this hypothesis by screening the WT1 gene for mutation in 12 46,XY patients with various forms of genital abnormality. Using single strand conformation polymorphism (SSCP) we did not detect any WT1 mutations in these patients. However, in addition to the 12 patients, three DDS patients were also analysed using SSCP, and in all three cases heterozygous WT1 mutations were found which would be predicted to disrupt the DNA binding activity of WT1 protein. These results support the notion that DDS results from a dominant WT1 mutation. However, WT1 mutations are unlikely to be a common cause of male genital abnormalities when these are not associated with kidney abnormalities.

Base Sequence↗
PubMed1992

Localization of the citrate synthase (CS) gene to the p12-p13 bands of chromosome 5 in pigs by in situ hybridization.

Citrate synthase (CS) is a key enzyme of the Krebs tricarboxylic acid cycle. A 1.4 kb porcine CS cDNA probe was used to chromosomally localize the CS gene in pigs by in situ hybridization. Two in situ hybridization experiments were conducted. Although the first experiment indicated a distinct signal on the 5p12-p13 bands, a secondary signal was observed on the 13q24-q32 bands. Hence, a second in situ hybridization experiment was conducted at higher stringency. The results demonstrated a consistent signal on the 5p12-p13 bands, and the signal on chromosome 13 was scattered with no prominent secondary peak. The CS gene was therefore assigned to the p12-p13 bands of chromosome 5 in pigs.

Animals↗
PubMed1991

Tear film profile in dry eye.

Tear film profile was studied in 100 consecutive patients with dry eye along with 100 age and sex matched controls. The frequency of abnormal tear function tests observed in patients with dry eye and controls was: marginal tear strip 93% and 11%, rose bengal staining 89% and 0%, lissamine green staining 87% and 0%, BUT 79% and 14%, Schirmer test 79% and 3% and fluorescein staining 69% and 0%, respectively. No significant difference was observed between tear pH of patients with dry eye and that of normal healthy subjects. A new, simple and effective objective criteria of confirming and grading dry eye based upon a points scoring system derived from the results of various tear film tests is suggested.

Adolescent↗