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Biomedical subjects

P Patel

Publications and source records attributed to P Patel.

At least 199 records · Page 11Linked to original sources
PubMed1991

Patterns of epithelial migration in the unaffected ear in patients with a history of unilateral cholesteatoma.

Epithelial migration in a centrifugal manner is an established phenomenon in the normal human tympanic membrane. This pattern of migration is symmetrical in both ears of any one individual. We present a prospective study on the pattern of tympanic ink dot migration on the normal drum, in patients with a history of cholesteatoma in one ear. It was demonstrated that patients who develop cholesteatoma have a normal migratory pattern and rate in the unaffected ear. The conclusion from this study is that defective migration is not the initiating factor in the development of acquired cholesteatoma.

Cell Movement↗
PubMed1991

Brain atrophy in Werdnig-Hoffmann disease.

CT scan imaging of the brain was done in eight children with Werdnig-Hoffmann Disease. Seven of them showed generalized cerebral cortical atrophy and one had low attenuated, non-enhancing areas in the white matter involving both frontal lobes. These changes could be due to repeated episodes of hypoxic injury.

Atrophy↗
PubMed1991

The effect of distension of the urinary bladder on coronary blood flow in anesthetized dogs.

To determine whether distension of the urinary bladder reflexly affects coronary blood flow, experiments were performed in eleven dogs anaesthetized with sodium pentobarbitone. Both ureters were cannulated and the urinary bladder was distended with warm Ringer solution at a steady intravesical pressure. Arterial blood pressure was prevented from changing by a pressurized reservoir of warm Ringer solution connected to the femoral arteries. Coronary blood flow was measured with an electromagnetic flowmeter positioned around the origin of the left circumflex coronary artery. When the reflex increase in heart rate was prevented by atrial pacing in seven dogs, distension of the urinary bladder always caused a decrease in mean coronary blood flow. Similar results were obtained in all eleven dogs after administration of propranolol. The decrease in mean coronary blood flow was significantly reduced by atropine or bilateral cervical vagotomy, and was abolished by bretylium tosylate. The results showed that distension of the urinary bladder reflexly decreased mean coronary blood flow, a response involving efferent cardiac vagal and sympathetic pathways.

Animals↗
PubMed1991

Specific and nonspecific antibody responses in different segments of the respiratory tract in rats infected with Mycoplasma pulmonis.

Murine respiratory mycoplasmosis resulting from Mycoplasma pulmonis infection in rats provides a useful model for the study of immunological and inflammatory mechanisms operative in the respiratory tract. We have previously shown that LEW rats develop more severe disease than do F344 rats. To further study the production of antibody responses in chronic respiratory disease due to M. pulmonis infection, we examined the distribution and development of M. pulmonis-specific antibody-forming cells (AFC) in different segments of the respiratory tracts of infected LEW and F344 rats. In these studies, the upper respiratory nodes were the initial site of antibody production after infection and remained the major site for recovery of AFC. Since infected LEW rats had equal or higher numbers of AFC than did infected F344 rats, these results suggest that the level of local antibody production alone is not responsible for the decreased susceptibility of F344 rats to murine respiratory mycoplasmosis. The differences in total antibody responses appear to be due to the greater numbers of cells recovered from the tissues of infected LEW rats compared with those recovered from F344 rats, suggesting that LEW rats may have greater production of chemotactic factors. Also, we demonstrate that nonspecific activation and/or recruitment of B cells occurs in the respiratory tracts of both LEW and F344 rats after infection with M. pulmonis.

Animals↗
PubMed1991

Shared antigenicity and immunogenicity of type 4 pilins expressed by Pseudomonas aeruginosa, Moraxella bovis, Neisseria gonorrhoaea, Dichelobacter nodosus, and Vibrio cholerae.

Immunoblotting with polyclonal rabbit antibodies raised against pilins expressed by Pseudomonas aeruginosa, Moraxella bovis, Neisseria gonorrhoeae, Dichelobacter nodosus, and Vibrio cholerae was used to demonstrate that these polypeptides display conserved antigenic and, in most cases, immunogenic determinants. These determinants appear to be localized to the highly homologous amino-terminal domains (residues 1 to 25).

Animals↗
PubMed1991

Detection of mutations in insulin-receptor gene in NIDDM patients by analysis of single-stranded conformation polymorphisms.

We used the recently described technique of single-stranded conformation-polymorphism (SSCP) analysis to examine the insulin-receptor locus. First, the ability of the method to detect known mutations and polymorphisms in the insulin-receptor coding sequence was assessed. Regions of the insulin-receptor sequence containing 16 different nucleotide changes, 9 in patient genomic DNA and 7 as cloned cDNA in plasmids, were analyzed. All 9 patient genomic DNA mutants and 5 of 7 plasmid mutants exhibited variant SSCP patterns. To investigate the potential of the technique for screening many patients, the 5 exons that encode the tyrosine kinase domain of the insulin receptor were examined in 30 unrelated white subjects with non-insulin-dependent diabetes mellitus (NIDDM). Exons 17-21 were amplified from genomic DNA with polymerase chain reaction and subjected to SSCP analysis. Exons 19, 20, and 21 revealed no bands of aberrant migration, suggesting a high degree of conservation of these sequences. One diabetic subject had an SSCP variant in exon 18. Direct sequencing of this subject's genomic DNA revealed a heterozygous missense mutation (Lys1068----Glu1068). Five different SSCP patterns were detected in exon 17. Based on direct sequencing, these patterns were explained by combinations of three different nucleotide substitutions, two of which were common silent polymorphisms. One subject had a heterozygous missense mutation Val985---- Met985. Allele-specific oligonucleotide hybridization confirmed the presence of these mutations in the appropriate diabetic subjects and also detected the Val985 mutation in heterozygous form in 1 of 13 nondiabetic white subjects. SSCP analysis is a sensitive rapid method for screening for mutations in the insulin-receptor gene.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗
PubMed1990

ChlVPP combination chemotherapy for Hodgkin's disease: long-term results.

Two hundred and eighty-four patients with advanced Hodgkin's disease (HD) (stage II with poor prognostic features and stage III/IV) have been treated with the ChlVPP combination chemotherapy regimen (chlorambucil, vinblastine, procarbazine and prednisolone) in a single-centre unselected series. Median follow up is 92 months. Fifty-five patients had previously received radiotherapy but none had received previous chemotherapy. Eighty-five per cent of previously untreated patients and 91% of previously irradiated patients entered complete remission (CR); 71% and 68% of these respectively remain in CR at 10 years and 65% and 64% of each group respectively are alive at 10 years. On univariate analysis, age, stage, site of visceral disease and lymphocyte count predicted survival and on multivariate analysis age, absence of symptoms, absence of lung, liver or bone marrow disease and achieving a CR remained important predictors of survival. Acute toxicity was mild. The 10 year actuarial risk of acute leukaemia was 2.7%. This study adds further support to the view that chlorambucil is as effective and less toxic than mustine in combination chemotherapy for HD. We suggest that MOPP chemotherapy is no longer routinely indicated for HD.

Adolescent↗
PubMed1990

Purification and characterization of two forms of hydrogenase isoenzyme 1 from Escherichia coli.

A hydrogenase associated with dihydrogen uptake (HUP hydrogenase) was purified from an Escherichia coli mutant (strain SE1100) defective in utilization of molybdate and thus fermentative dihydrogen production. This protein had two subunits with apparent molecular weights of 59,000 and 28,000 (form 1). An immunologically cross-reactive hydrogenase was also purified from E. coli K10 grown in glucose-minimal medium and harvested at the mid-exponential phase of growth. Upon purification to homogeneity, this hydrogenase contained only one subunit with an apparent molecular weight of 59,000 (form 2). The two forms of the HUP hydrogenase exhibited similar kinetic characteristics. The electrophoretic properties of the enzyme and its response to pH suggest that this HUP hydrogenase is the HYD1 isoenzyme. The HYD1 isoenzyme was the only hydrogenase detectable during the stationary phase of growth in E. coli grown in Mo-deficient medium.

Cell Fractionation↗
PubMed1990

Chromosome 11 allele loss in sporadic insulinoma.

DNA was extracted from tissue samples of three unrelated cases of insulinoma. Chromosome 11 allele loss was investigated using several chromosome 11 specific probes which detect restriction fragment length polymorphisms. In one case, which proved informative for many of the chromosome 11 markers, allele loss was shown on both 11p and 11q. This finding is of considerable interest as the allele loss closely corresponds to that recently reported in insulinomas occurring in the familial multiple endocrine neoplasia type 1 (MEN-1) syndrome.

Adenoma, Islet Cell↗
PubMed1990

Dose-response effects of two sizes of monodisperse isoproterenol in mild asthma.

The dose-response effect of monodispersed isoproterenol of two different sizes (diameters 2.5 and 5 microns) was examined in eight mild asthmatic subjects (baseline FEV, 81.5% of predicted). Pulmonary and cardiovascular variables were measured before and following 1, 2, 4, 8, and 16 cumulative min of aerosol inhalation. Subjects inhaled 1 to 30 micrograms (2.5-microns particles) or 2 to 50 micrograms (5-microns particles) of isoproterenol. Pulmonary but not cardiac responses were significantly greater for the 2.5-microns particles as compared to equivalent doses of 5-microns particles. Pulmonary dose-related response differences were particularly marked for variables associated with small airway function (FEF25-75 and FEF75-85). These findings suggest that small particles penetrate more deeply into the lung and thereby more effectively dilate small airways and that small amounts of appropriately sized inhaled bronchodilator may produce considerable therapeutic effects.

Adult↗
PubMed1989

Prenatal sex determination by DNA amplification from maternal peripheral blood.

The polymerase chain reaction was used to amplify a Y-specific repeat sequence in peripheral blood DNA samples from 19 pregnant women who had a gestational age of 9 to 41 weeks. Y-specific sequences were amplified from all 12 women who bore a male fetus but in none of 7 women who bore a female fetus. With stringent precautions against contamination, this technique may assist prenatal diagnosis of sex-linked genetic disorders.

Blood↗