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Biomedical subjects

R Patel

Publications and source records attributed to R Patel.

At least 271 records · Page 15Linked to original sources
PubMed1994

Infections due to nontuberculous mycobacteria in kidney, heart, and liver transplant recipients.

Infections due to nontuberculous mycobacteria (NTM) in solid-organ transplant recipients are infrequent but may be a major cause of morbidity. We describe four cases of NTM infection in solid-organ transplant recipients. The manifestations included a nodule secondary to Mycobacterium kansasii infection in a heart transplant recipient, a cutaneous lesion and a pulmonary nodule secondary to M. kansasii infection in a renal transplant recipient, tenosynovitis secondary to Mycobacterium chelonae infection in a renal transplant recipient, and cutaneous lesions secondary to M. chelonae infection in a liver transplant recipient. We also summarize previously reported cases of NTM infections in solid-organ transplant recipients; common manifestations of NTM infections in solid-organ transplant recipients include cutaneous lesions of the extremities, tenosynovitis, and joint infection. Histopathologic examination of aspirates or biopsy specimens from involved areas and staining and culture for mycobacteria are essential for diagnosis. Treatment of NTM infection most commonly involves surgery, reduction in doses of immunosuppressive medications, and/or therapy with antimycobacterial medications; these treatments are often associated with a good outcome.

Adult↗
PubMed1994

The cell cycle effects and induction of apoptosis by 5-bromouridine in cultures of human leukaemic MOLT-4 and HL-60 cell lines and mitogen-stimulated normal lymphocytes.

5-Bromouridine (BrUrd) and several analogues of this antimetabolite exhibit antiviral activity and are potent inhibitors of the human immunodeficiency virus. The antitumour activity of BrUrd, however, in comparison with 5-fluorouridine or 5-fluorouracil, is less pronounced. Because BrUrd is incorporated into RNA and can be detected immunocytochemically and analysed by cytometry, it may prove useful as an RNA precursor to assay cell transcriptional activity. The aim of the present study was to evaluate the cell cycle effects of BrUrd incorporation in human lymphocytic leukaemic MOLT-4 and HL-60 cells and mitogenically stimulated normal peripheral blood lymphocytes. BrUrd suppressed cell proliferation and induced cell death; when measured after 72 h of treatment, the LD50 was 10 and 20 microM for HL-60 and MOLT-4, respectively, and LD90 was 100 microM, for both cell lines. BrUrd was maximally incorporated by the cells progressing through S phase of the cycle and the S phase cells were most severely perturbed by the drug, which was detected in RNA but not in DNA. Suppression of the S phase traverse of MOLT-4, HL-60 and normal lymphocytes was seen at > or = 30 microM BrUrd concentration. Also sensitive was the cell traverse through G2+M which, in the case of lymphocytes, HL-60 and MOLT-4 cells, was perturbed at > or = 30, > or = 200 and 500 microM BrUrd concentrations, respectively. Transition of lymphocytes from G0 to G1 was little affected at < 100 microM, and, although suppressed, was still observed even at 500 microM BrUrd concentration. Apoptosis of HL-60 cells and lymphocytes was observed at > or = 50 microM BrUrd after 24 h of incubation; death of MOLT-4 cells had mixed features of apoptosis and necrosis and resembled the 'mitotic' or 'reproductive cell death' as described in other cell systems. The cytostatic and cytotoxic effects of BrUrd should be taken into consideration when using this antimetabolite as an antiviral agent in the clinic or as an RNA precursor in assays of cell transcriptional activity.

Antimetabolites↗
PubMed1994

Detection of cytomegalovirus DNA in sera of liver transplant recipients.

We prospectively studied the utility of the amplification of cytomegalovirus (CMV) DNA in the sera of liver transplant recipients in order to predict symptomatic CMV infection, thus enabling preemptive therapy with antiviral agents. Serum samples obtained at biweekly intervals from 20 sequential liver transplant recipients for at least 8 weeks following transplantation were tested by the PCR amplification procedure. Results were correlated with blood and urine cultures, histopathological findings from infected organs, and clinical manifestations. Six patients (30%) developed symptomatic CMV infection; in five (83%) of these patients, CMV DNA was detected prior to symptomatic CMV infection, and in one (17%) of these patients, CMV DNA was detected at the time of symptomatic CMV infection. CMV DNA was detected a mean of 13 days (range, 0 to 23 days) prior to the onset of symptomatic CMV infection. In addition, CMV DNA was detected in the sera of four of five patients with asymptomatic viremia and two patients with asymptomatic viruria. Lastly, the PCR was negative for sera from seven patients with no evidence of CMV infection. We found that PCR was able to detect the presence of CMV DNA in the sera of liver transplant recipients at a sensitivity of 92% and a specificity of 100% for CMV infection, while the sensitivity and specificity for symptomatic infection were 100 and 57%, respectively.

Base Sequence↗
PubMed1994

The eating attitudes and behaviours of Asian and British schoolgirls: a pilot study.

This study set out to examine dietary, weight and eating attitudes of 12-18 year old British and Asian girls. Ninety-six subjects from a state school completed the Eating Attitudes Test (EAT-26), the Binge Eating Questionnaire (BEQ) and a questionnaire concerning the perceived level of integration into British society. The mean EAT-26 score was higher than any other study has found using a school population. No significant correlation was found between age and EAT-26 score, and there was no significant difference between the Asian and British mean EAT-26 scores. The EAT-26 scores were not significantly higher in girls from families of higher socioeconomic class compared to those from lower socioeconomic class. There was however some support for the prediction that resentment in the Asian girls was expressed in higher EAT-26 scores. No significant group difference was found between Asian and British girls with regard to vomiting behaviour. The results are discussed in terms of the literature on eating disorders.

Acculturation↗
PubMed1994

Initiation of growth inhibition by TGF beta 1 is unlikely to occur in G1.

Type beta transforming growth factors represent a family of polypeptides that modulate growth and differentiation. They exert their effect on target cells through interaction with multiple cell surface receptors. Transforming growth factor-beta 1 has a strong inhibitory action on cell division in mink lung CC164 cells, a process that is initiated by immediate induction of junB and phosphorylation of nuclear protein followed by a reduced expression of cdk4. However, its signal transduction pathways are still unresolved. In this study we report a detailed analysis of cell kinetic events following addition of transforming growth factor-beta 1 to mink lung CCL64 cells. We show that transforming growth factor-beta 1 reduces [3H]thymidine incorporation after a delay of 8 hours, which reaches its nadir at 16 hours. The reduced growth rate is maintained for at least 48 hours as shown by flow cytometric analysis of DNA content. Using time-lapse video microscopy it was shown that control cells double on average every 14.4 hours, whereas the transforming growth factor-beta 1-treated cells have a doubling time of on average 20.3 hours. The difference in intermitotic time is a consequence of a prolonged G1 phase (a shift from 7.5 to 13.5 hours on average). However, changes in intermitotic times occur only after cells have undergone division in the presence of transforming growth factor-beta 1 and treated cells finish the ongoing cell cycle exactly like control cells. From these findings we conclude that transforming growth factor-beta 1 may change cell cycle parameters by interfering with cellular events prior to G1.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

The prevalence of eye disease in Leicester: a comparison of adults of Asian and European descent.

Random samples of people aged 40 years and over were drawn from lists of patients registered with two neighbouring inner-city general practices: one predominantly with Asian patients and the other predominantly with European patients. The people selected were invited to attend specially arranged eye clinics for examination by an ophthalmologist and an optician. We examined 377 people and found that, compared to people of European descent, Asians had a significantly higher prevalence of age-related cataract: 30% compared to 3% in people aged under 60 years and 78% compared to 54% in those aged 60 years and over. The age of onset of cataract seems to be earlier in Asians. After adjustment for age, there were no statistically significant ethnic differences in the prevalences of open-angle glaucoma, macular degeneration or diabetic retinopathy.

Adult↗
PubMed1993

Activation of phosphatidylinositol 3-kinase and phosphatidylinositol 4-kinase during rat parotid acinar cell proliferation.

We have recently shown that beta-adrenergic agonist, isoproterenol-induced parotid acinar cell proliferation is in part mediated by elevated levels of surface galactosyltransferase which undergoes interaction with the EGF-R. The receptor subsequently undergoes autophosphorylation on the tyrosine residues in a manner similar to its 'receptor-ligand' interaction (Purushotham et al. (1992) Biochem. J. 284, 767-776). In this study, we provide evidence for phosphatidylinositol 3-kinase and 4-kinase as cytoplasmic signalling proteins involved in both the isoproterenol and EGF-stimulated signal transduction upon in vitro and in-vivo stimulation of parotid acinar cells. Total cell lysate activity for the PtdIns 4-kinase was 2- and 3-fold higher than unstimulated control cells, while the PtdIns 3-kinase was 1.4- and 2.8-fold higher following stimulation by isoproterenol or EGF, respectively. Increases of 6- and 2-fold in phosphatidylinositol 3-kinase were observed in anti-phosphotyrosine-antibody-immunoprecipitated cell lysates upon in-vitro growth stimulation with isoproterenol or EGF, respectively. There was an increase in tyrosine phosphorylation of the holoenzyme and association of the p85 subunit of phosphatidylinositol 3-kinase with EGF-R in response to both isoproterenol and EGF treatments. This corresponded with the mobilization of p85 from the cytoplasm to the plasma membrane upon growth stimulation. These results further implicate the phosphoinositide metabolites in the second messenger signalling pathways of isoproterenol-induced rat parotid cell proliferation. The parallel utilization of EGF indicate that the post-transductional mechanisms of isoproterenol-induced acinar cell proliferation are similar to the growth-factor-mediated activation of intracellular signalling pathways for cell growth.

1-Phosphatidylinositol 4-Kinase↗
PubMed1993

Characterization and N-terminal amino acid sequences of beta-(1-4)endoxylanases from Streptomyces roseiscleroticus: purification incorporating a bioprocessing agent.

Streptomyces roseiscleroticus produces extracellular xylanases when cultured on a liquid xylan medium. Purified xylanases are used to facilitate bleaching of kraft pulps in the pulp and paper industry. Downstream processing and purification of xylanases from S. roseiscleroticus is difficult unless red pigments produced by the bacterium are removed. We report that the bioprocessing agent, Biocryl BPA-1000, removes these pigments allowing purification of four xylanases by HPLC employing cation exchange, hydrophobic interaction, and gel filtration. The xylanases have been named Xyl1, Xyl2, Xyl3, and Xyl4 according to their order of elution from the cation exchange column. The purified xylanases have been characterized according to their molecular weights, pH and temperature stabilities, N-terminal amino acid sequences, and hydrolysis action patterns on oat spelt xylan. The molecular weights by mass spectroscopy for Xyl1-Xyl4 are 33,647, 33,655, 21,070, and 46,855, respectively. All four xylanases exhibit pH optima between 5.0 and 7.0 and temperature optima between 50 and 60 degrees C. The N-terminal amino acid sequences are compared to sequences from Streptomyces lividans, Streptomyces 36A, and a Chainia sp. The N-terminal amino acid sequence of Xyl1 appears to be unique, but sequences from Xyl2, 3, and 4 bear strong homology to xylanases cloned from S. lividans. Xyl3 is also homologous to xylanases from Streptomyces 36A, and a Chainia sp. Predominant products of arabinoxylan hydrolysis by the purified xylanases included xylotriose, tetraose, and pentaose. None of the xylanases purified from S. roseiscleroticus produced xylose.

Amino Acid Sequence↗
PubMed1993

An improved motorcycle helmet design for tropical climates.

Approximately 20% of all fatal traffic crashes in India involve riders of motorized two-wheelers. Head protection of two-wheeler riders is therefore a very important issue. This paper reports the results of a survey of patterns of motorcycle helmet use in Delhi, and the design details of a more comfortable helmet. The survey results were used as guidelines for designing a safer helmet, with a better ventilating system, to promote wider use. In the new design additional protection is provided on the sides of the helmet, since our earlier studies showed that more head injuries occur on the side of the head than on the top. A low-cost locking device has also been developed with which the helmet can be secured to the vehicle when not in use. All these design features are incorporated into a stylized product form. The new design is being marketed by a Delhi-based manufacturer and has received a very favourable response in the market.

Journal Article↗
PubMed1993

Comparison of patients with enterococcal bacteremia due to strains with and without high-level resistance to gentamicin.

Patients with enterococcal bacteremia due to strains with and without high-level gentamicin resistance (HLGR; MIC, > 2,000 mg/L) were compared. Between 1986 and 1991, there were 178 episodes of enterococcal bacteremia: 47 and 131 episodes, respectively, due to enterococcal strains with and without HLGR. Sixty-two, 57, and 59 episodes, respectively, were in patients with transient bacteremia (a single positive blood culture), bacteremia (two or more positive blood cultures), and polymicrobial bacteremia. Nosocomial bacteremia accounted for 61.7% and 51.1% of episodes due to strains with and without HLGR, respectively. All isolates were strains of Enterococcus faecalis except for 13 strains of Enterococcus faecium, 4 of Enterococcus avium, and 3 of Enterococcus durans. Although the mortality was slightly higher among patients infected with strains with HLGR than among those infected with strains without HLGR (38.3% vs. 30.5%, respectively), there was no statistical difference. The mortality rate was adversely affected by old age (P < .01) and rapidly and ultimately fatal underlying conditions (P < .001). The addition of gentamicin to the treatment regimens had no effect on mortality.

Adolescent↗
PubMed1993

Bacteremia due to Enterococcus avium.

Enterococcus avium, formerly "group Q streptococcus," has rarely been reported as a pathogen in humans. To determine the clinical significance of this organism, we reviewed the records of all patients whose blood cultures were positive for E. avium who were seen at our institution from 1986 through 1991 and identified nine cases of bacteremia due to E. avium. All isolates were believed to be clinically significant. Five of nine cases developed in patients with significant gastrointestinal illnesses. The remaining clinical scenarios included intravenous catheter sepsis and factitious disorders. E. avium bacteremias were polymicrobial in seven cases; in six cases, the coisolates were gastrointestinal organisms. These observations suggest that E. avium bacteremia most often originated from a gastrointestinal tract source. We conclude that, though rare, E. avium can be pathogenic in humans and that E. avium bacteremia is associated with gastrointestinal abnormalities.

Adult↗
PubMed1993

Effects of N-acetylglucosamine on carbohydrate fermentation by Streptococcus mutans NCTC 10449 and Streptococcus sobrinus SL-1.

We have investigated the ability of two species of streptococci isolated from the human oral cavity (Streptococcus mutans NCTC 10449 and Streptococcus sobrinus SL-1) to metabolize N-acetylglucosamine (GlcNAc), a naturally occurring amino sugar present in saliva and human glycoproteins, when provided as the sole fermentable carbohydrate and determined the effects of the presence of GlcNAc on the fermentation of other carbohydrates. S. mutans used GlcNAc at concentrations of up to 10 mM to increase cell numbers, but S. sobrinus was unable to ferment the amino sugar alone and its uptake only occurred in the presence of a fermentable carbohydrate. GlcNAc had a marked inhibitory effect on the ability of S. sobrinus to produce lactic acid from glucose, sucrose, and fructose, at the same time increasing the lag period and doubling time of batch-grown cells. Such patterns of inhibition were found with S. mutans, but the effects were less than those seen in S. sobrinus. In mixed culture studies of the two species, S. sobrinus became the predominant organism when 10 mM glucose was supplied as the sole fermentable carbohydrate, with a concomitant decrease in the numbers of S. mutans cells, but supplementation of the broth with 10 mM glucose and 10 mM GlcNAc resulted in the emergence of S. mutans as the predominant organism. S. mutans and S. sobrinus grown in media containing glucose possessed the ability to transport glucose and GlcNAc, probably via the same glucose-phosphotransferase system at similar rates. However, intracellular levels of N-acetylglucosamine-6-phosphate deacetylase and glucosamine-6-phosphate deaminase were markedly higher in S. mutans grown on glucose and GlcNAc than in S. sobrinus: 34 and 398 and 8 and 17 nmol of NADPH formed per mi per mg of protein for S. mutans and S. sobrinus, respectively. We propose that GlcNAc inhibited growth of S. sobrinus in media containing glucose and GlcNAc by competing with glucose for the glucose phosphotransferase, depleting intracellular levels of phosphoenolpyruvate, and possessing, in contrast to S. mutans, low levels of N-acetyl-glucosamine-6-phosphate deacetylase and glucosamine-6-phosphate deaminase activity. Together, these data suggest that in dental plaque, S. sobrinus when exposed to GlcNAc will have a reduced ability to compete with S. mutans for dietary carbohydrates, contributing to the greater frequency of isolation of S. mutans from human populations.

Acetylglucosamine↗
PubMed1993

Altered left atrial compliance after atrial appendectomy. Influence on left atrial and ventricular filling.

Previous studies have shown regional differences in atrial distensibility. We studied 12 open-chest dogs to test the hypothesis that left atrial compliance is decreased after removal of the left atrial appendage and to determine the effect of altered atrial compliance on atrial reservoir and conduit function. Sonomicrometer crystal pairs were used to measure the long- and short-axis diameters of the left atrium over a wide range of intracardiac pressures and volumes obtained by intravenous hetastarch infusion both before and after suture ligation of the left atrial appendage (appendectomy). Pulmonary venous flow was measured with an ultrasonic flowmeter, and transmitral flow velocities were measured with transesophageal Doppler echocardiography. After appendectomy, the diastolic pressure-volume relation was shifted upward and to the left in six of seven dogs. The mean dynamic stiffness constant of the left atrial diastolic pressure-volume relation was significantly greater after appendectomy than before (0.20 +/- 0.11 [mean +/- SD] versus 0.14 +/- 0.08 ml-1, p < 0.01); the mean y intercept was slightly, but significantly, less after appendectomy (0.6 +/- 0.3 versus 1.3 +/- 0.6 mm Hg, p < 0.05). The left atrial reservoir volume (maximum minus minimum left atrial volume) was significantly less after appendectomy at matched left atrial pressures. The systolic to diastolic flow integral ratio of pulmonary venous flow (JFTI/KFTI), an index of the relative reservoir to conduit functions of the left atrium, increased significantly with volume infusion only before appendectomy; at matched left atrial pressure, JFTI/KFTI was significantly less afterwards.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Bar-code technology applied to drug-use evaluation.

Bar-code technology was used to determine: (1) patterns in histamine H2-receptor antagonist use and (2) the occurrence of adverse drug effects and drug interactions associated with the use of these agents in critically ill patients. Patients at Henry Ford Hospital (Detroit) receiving histamine H2-receptor antagonists over a two-month period were evaluated. Clinical information was collected in the intensive care units by using a bar-code system. The data-capture menu was based on drug-use-evaluation criteria for H2-receptor antagonists. Data collected in the scanning wands were uploaded into a computer database and were analyzed at the end of the study. Data were collected for 207 patients. Cimetidine was the predominant H2-receptor antagonist used, and the predominant indication was stress-ulcer prophylaxis. Dosing trends followed accepted guidelines for cimetidine dosage adjustment in renal and hepatic failure. Two drug interactions and six adverse drug reactions occurred. Pharmacists made 92 recommendations to the medical staff regarding modification in therapy, involving 32% of the patients. Data collection required an average of 10 minutes per day each for three pharmacists. H2-receptor antagonist use patterns were evaluated in intensive care units through the application of bar-code technology. The speed and efficiency of this automated tool facilitated collection of a large amount of data.

Clinical Pharmacy Information Systems↗