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Biomedical subjects

R Patel

Publications and source records attributed to R Patel.

At least 55 records · Page 3Linked to original sources
PubMed2001

Culture with BACTEC Peds Plus/F bottle compared with conventional methods for detection of bacteria in synovial fluid.

An evaluation was undertaken to determine the utility of the BACTEC Peds Plus/F bottle and the BACTEC 9240 instrument (Becton Dickinson Diagnostic Instrument Systems, Sparks, Md.) for the detection of clinically significant microorganisms in synovial fluid specimens. The Peds Plus/F bottle was used because in our laboratory the quantity of synovial fluid available for culture is frequently in the range of 0.5 to 3.0 ml. The culture results obtained with the Peds Plus/F bottle were compared to those obtained by a conventional agar plate method for a total of 805 synovial fluid specimens. Microbial growth was produced by 74 cultures (9.2%) from 60 patients, yielding a total of 77 microorganisms. Organisms were classified as pathogens (n = 62), contaminants (n = 12), or indeterminate (n = 3) on the basis of a review of the patients' medical histories. Culture using BACTEC Peds Plus/F bottle detected statistically significantly more pathogens overall (62 versus 51 pathogens [P = 0.001]) and statistically fewer contaminants overall (1 versus 11 contaminants [P = 0.006]) than culture by the agar plate method. These results indicate the superior performance of the BACTEC Peds Plus/F bottle over the conventional agar plate method for the detection of clinically significant microorganisms from synovial fluid specimens.

Arthritis, Infectious↗
PubMed2001

Detection of herpes simplex virus DNA in genital and dermal specimens by LightCycler PCR after extraction using the IsoQuick, MagNA Pure, and BioRobot 9604 methods.

We evaluated two automated systems, MagNA Pure (Roche Molecular Biochemicals, Indianapolis, Ind.) and BioRobot 9604 (Qiagen, Inc., Chatsworth, Calif.) as effective replacements for the manual IsoQuick method (Orca Research, Inc., Bothell, Wash.) for extraction of herpes simplex virus (HSV) DNA from dermal and genital tract specimens prior to analysis by LightCycler PCR. Of 198 specimens (152 genital, 46 dermal), 92 (46.2%) were positive for HSV DNA by LightCycler PCR after automated extraction of specimens with either the MagNA Pure or BioRobot 9604 instrument. The manual IsoQuick method yielded HSV DNA (total n = 95) from three additional specimens that were negative by the automated method (P = 0.25, sign test). Although the mean numbers of LightCycler PCR cycles required to reach positivity differed statistically significantly among all three of the methods of extraction, the estimated means differed by no more than 1.5 cycles (P < 0.05). Seventy (76%) of the 92 specimens that were LightCycler PCR positive by all three extraction methods were also positive by shell vial cell culture assay. HSV DNA was detected by a lower LightCycler PCR cycle number (26.1 cycles) in specimens culture positive for the virus than in culture-negative samples (33.3 cycles) (P < 0.0001). The manual IsoQuick and automated MagNA Pure and BioRobot 9604 methods provide standardized, reproducible extraction of HSV DNA for LightCycler PCR. The decision to implement a manual versus an automated procedure depends on factors such as costs related to the number of specimens processed rather than on the minimal differences in the technical efficiency of extraction of nucleic acids among these methods.

DNA, Viral↗
PubMed2001

Multiple coronary aneurysms in a patient with neurofibromatosis type 1: case report and intravascular ultrasound of aneurysm.

A 54 year old woman with neurofibromatosis type 1 (NF-1) was found to have multiple coronary aneurysms. Intraoperative intravascular ultrasound (IVUS) revealed severe coronary disease proximal to the aneurysm that had not been apparent angiographically. An IVUS picture of one of the giant coronary aneurysms is also shown. The vascular manifestations of neurofibromatosis and the causes of coronary aneurysms are reviewed.

Coronary Aneurysm↗
PubMed2001

Access to genitourinary medicine clinics in the United Kingdom.

OBJECTIVES: To assess the variability in time taken for a patient to be seen in a genitourinary (GUM) clinic in the United Kingdom having contacted that clinic by telephone and compare this with GUM physicians' expectations. METHODS: A postal questionnaire was sent to lead GUM physicians asking when they thought patients with two specific clinical scenarios would be seen in their clinics. Following this, healthcare personnel contacted individual units posing as patients with the same clinical scenarios and asked to be seen as soon as possible. RESULTS: 202/258 (78%) lead clinicians responded to the postal questionnaire. All clinics claimed to have procedures allowing patients with acute symptoms to be assessed urgently and estimated that such patients would be seen within 48 hours of the initial telephone contact. In 243 of 311 (78%) clinic contacts, the patient was invited to attend the clinic within 48 hours. For the remaining 68 contacts (22%) the patient could not be accommodated within 48 hours and, of these, 49 could not be seen for more than 1 week. CONCLUSIONS: No clinician estimated that patients with acute severe symptoms would be seen more than 48 hours after the initial telephone contact, but in reality, for 22% of the patient contacts this was the case. This study may well underestimate the difficulties the general public may have in accessing GUM services. We hypothesise that this situation could be ameliorated by establishing process standards and addressing issues of resource allocation.

Acute Disease↗
PubMed2001

Endothelial dysfunction is induced by proinflammatory oxidant hypochlorous acid.

The myeloperoxidase (MPO)-derived oxidant hypochlorous acid (HOCl) plays a role in tissue injury under inflammatory conditions. The present study tests the hypothesis that HOCl decreases nitric oxide (NO) bioavailability in the vasculature of Sprague-Dawley rats. Aortic ring segments were pretreated with HOCl (1-50 microM) followed by extensive washing. Endothelium-dependent relaxation was then assessed by cumulative addition of acetylcholine (ACh) or the calcium ionophore A23187. HOCl treatment significantly impaired both ACh- and A23187-mediated relaxation. In contrast, endothelium-independent relaxation induced by sodium nitroprusside was unaffected. The inhibitory effect of HOCl on ACh-induced relaxation was reversed by exposure of ring segments to L-arginine but not D-arginine. In cellular studies, HOCl did not alter endothelial NO synthase (NOS III) protein or activity, but inhibited formation of the NO metabolites nitrate (NO3(-) and nitrite (NO2(-). The reduction in total NO metabolite production in bovine aortic endothelial cells was also reversed by addition of L-arginine. These data suggest that HOCl induces endothelial dysfunction via modification of L-arginine.

Acetylcholine↗
PubMed2001

Dual signaling by the alpha(v)beta(3)-integrin activates cytosolic PLA(2) in bovine pulmonary artery endothelial cells.

Vitronectin, which ligates the alpha(v)beta(3)-integrin, increases both lung capillary permeability and lung endothelial Ca(2+). In stable monolayers of bovine pulmonary artery endothelial cells (BPAECs) viewed with confocal microscopy, multimeric vitronectin aggregated the apically located alpha(v)beta(3)-integrin. This caused arachidonate release that was inhibited by pretreating the monolayers with the anti-alpha(v)beta(3) monoclonal antibody (MAb) LM609. No inhibition occurred in the presence of the isotypic MAb PIF6, which recognizes the integrin alpha(v)beta(5). Vitronectin also caused membrane translocation and phosphorylation of cytosolic phospholipase A(2) (cPLA(2)) as well as tyrosine phosphorylation of the mitogen-activated protein kinase (MAPK) extracellular signal-regulated kinase (ERK) 2. The cPLA(2) inhibitor arachidonyl trifluoromethylketone, the tyrosine kinase inhibitor genistein, and the MAPK kinase inhibitor PD-98059 all blocked the induced arachidonate release. PD-98059 did not inhibit the increase of cytosolic Ca(2+) or cPLA(2) translocation, although it blocked tyrosine phosphorylation of ERK2. Moreover, although the intracellular Ca(2+) chelator MAPTAM also inhibited arachidonate release, it did not inhibit tyrosine phosphorylation of ERK2. These findings indicate that ligation of apical alpha(v)beta(3) in BPAECs caused ERK2 activation and an increase of intracellular Ca(2+), both conjointly required for cPLA(2) activation and arachidonate release. This is the first instance of a tyrosine phosphorylation-initiated "two-hit" signaling pathway that regulates an integrin-induced proinflammatory response.

Animals↗
PubMed2001

Protein kinase B/Akt activates c-Jun NH(2)-terminal kinase by increasing NO production in response to shear stress.

Laminar shear stress activates c-Jun NH(2)-terminal kinase (JNK) by the mechanisms involving both nitric oxide (NO) and phosphatidylinositide 3-kinase (PI3K). Because protein kinase B (Akt), a downstream effector of PI3K, has been shown to phosphorylate and activate endothelial NO synthase, we hypothesized that Akt regulates shear-dependent activation of JNK by stimulating NO production. Here, we examined the role of Akt in shear-dependent NO production and JNK activation by expressing a dominant negative Akt mutant (Akt(AA)) and a constitutively active mutant (Akt(Myr)) in bovine aortic endothelial cells (BAEC). As expected, pretreatment of BAEC with the PI3K inhibitor (wortmannin) prevented shear-dependent stimulation of Akt and NO production. Transient expression of Akt(AA) in BAEC by using a recombinant adenoviral construct inhibited the shear-dependent stimulation of NO production and JNK activation. However, transient expression of Akt(Myr) by using a recombinant adenoviral construct did not induce JNK activation. This is consistent with our previous finding that NO is required, but not sufficient on its own, to activate JNK in response to shear stress. These results and our previous findings strongly suggest that shear stress triggers activation of PI3K, Akt, and endothelial NO synthase, leading to production of NO, which (along with O(2-), which is also produced by shear) activates Ras-JNK pathway. The regulation of Akt, NO, and JNK by shear stress is likely to play a critical role in its antiatherogenic effects.

Adenoviridae Infections↗
PubMed2001

Medication management problems reported by subscribers to a school nurse listserv.

Given the potentially serious consequences of suboptimum medication management practices in elementary and secondary schools and the fact that this topic has been subject to little empirical inquiry, the purpose of this study was to obtain a preliminary understanding of the types of medication management problems that school nurses face, as well as the strategies they use to solve those problems. An analysis of messages related to medication management that appeared on the SCHLRN-L listserv (a 1,400-member discussion group for schools nurses) was performed. All messages sent to the listserv during a 5-month period were monitored. Any discussion thread that began during this time period and addressed the management of medications was selected for possible inclusion in the study. The result was a group of 71 threads. The listserv participants described a wide array of medication management problems and suggested numerous strategies for solving them. This study shows that serious medication management problems exist in schools and that school nurses make use of various strategies or "tricks of the trade" to handle these problems. This research highlights the need for a contribution from the pharmacy profession in this important and neglected area of drug therapy.

Adolescent↗
PubMed2001

Patients' perspectives on the burden of recurrent genital herpes.

The purpose of this study was to quantify the impact of recurrent genital herpes (RGH) on health-related quality of life, healthcare resource and workplace productivity. This was a cross-sectional survey conducted in 5 countries (Australia, Denmark, Italy, The Netherlands and UK). Patients with a confirmed history of RGH completed the MOS 36-Item Short Form Health Survey (SF-36) and the Recurrent Genital Herpes Quality of Life questionnaire (RGHQoL). Questionnaires addressing frequency of access to healthcare services and workplace productivity were also completed and patients' medical history was obtained. Scores for 6 of the 8 domains of the SF-36 were significantly lower (P<0.001) i.e. worse, compared with scores for the normal population. The RGHQoL score was significantly lower in patients experiencing more frequent or more severe recurrences. Forty-five per cent of patients estimated that their work effectiveness was reduced by between 25% and 50% due to genital herpes symptoms.

Adolescent↗
PubMed2001

Vertebral osteomyelitis and prosthetic joint infection due to Staphylococcus simulans.

Staphylococcus simulans, a coagulase-negative staphylococcus, is a common animal pathogen that is rarely encountered in human infections. We describe a 70-year-old man who developed multifocal vertebral osteomyelitis and late prosthetic joint infection caused by this pathogen. The patient was a farmer who had daily contact with cows and drank unpasteurized milk, although the portal of the pathogen's entry remains speculative. Culture of the vertebral disk biopsy specimen and cultures during resection arthroplasty yielded S. simulans. A review of the literature suggests that S. simulans may be more virulent than other species of coagulase-negative staphylococci. Accurate identification of S. simulans isolates would facilitate studies to further define its pathogenic role in human infections.

Agriculture↗
PubMed2001

Extension of a pulmonary blastoma into the left atrium.

Pulmonary tumors of embryonic origin are rare, and pulmonary blastomas are probably the most uncommon. A thorough literature search disclosed no previous reports of extension of this type of tumor into the heart. We describe a patient whose initial clinical presentation suggested an obstructive left atrial mass; however, clinical and histologic findings indicated the mass was a tumor that originated from a pulmonary blastoma that extended into the left atrium through a pulmonary vein. The unique aspect of this case is that the patient's symptoms were related to the obstructive effects of the atrial mass, not to the primary pulmonary tumor.

Cardiac Catheterization↗
PubMed2001

Rota-stenting of a calcified anomalous left coronary artery via the arm in a multi-vasculopathic patient.

Anomalous origins of the coronary arteries pose a challenge to the interventionalist. Diagnostic testing must take into account the possibility that perfusion patterns may be unusual but not pathologic, resulting in false-positive perfusion scanning. Treatment strategies must be customized to allow unusual access and passage of devices around angulations not commonly encountered. In this report, we describe a patient with severe peripheral arterial disease requiring the use of a 7 French multipurpose guide via the brachial approach for rotational atherectomy and stenting of a calcified and angulated anomalous left coronary.

Aged↗
PubMed2000

A novel high-throughput method for accurate, rapid, and economical measurement of multiple type 1 diabetes autoantibodies.

Prediction of Type 1 diabetes for study of preventive therapies requires screening the general population, where 85% of new cases occur. Even with HLA-based prescreening, nearly 20% of all children will need multiple serum autoantibody testings. High-throughput, economical, and accurate methods are therefore essential. We have developed such a radiobinding method, using 96-well microtiter plates and a novel immune complex capture method via membrane-bound Protein A. Each microtiter plate contained a standard negative control serum, and low-, medium-, and high-level positive control sera. All sera were evaluated in triplicate. This readily allowed quality control criteria both for triplicates of individual sera and for each 96-well plate. Inter-assay coefficients of variation (CVs) were all </=16%, while intra-assay CVs were all </=10%. The assay was found to be sensitive (to detect autoantibodies in patients) and specific (low reactivity in thousands of healthy volunteers). The format worked well using diverse antigens such as 35S-met-GAD65, 35S-met-ICA512/IA2, 35S-met-Phogrin, and 125I-insulin, and could be used for simultaneous screening of reactivity to both GAD65 and ICA512/IA2 in the same well. Diagnostic accuracy compared favorably with microcentrifuge tube-based Protein A-agarose GAD65 and IA2 autoantibody radiobinding assays and with acid-charcoal-polyethylene glycol (PEG) based competitive insulin autoantibody assays. In the case of 125I-insulin, comparing signal in the absence versus presence of cold insulin competitor was not necessary. Total serum volumes required were only 6 microl for GAD and ICA512, and only 15 microl for IAA. The method costs less than all other commonly used formats, and should be useful for population screening.

Adolescent↗
PubMed2000

Real-time detection of organic compounds in liquid environments using polymer-coated thickness shear mode quartz resonators

The selection of sensitive coatings is a critical task in the design and implementation of chemical sensors using coated thickness shear mode quartz crystal resonators (QCRs) for detection in liquid environments. This design or selection is performed through a study of the sorption process in terms of the partition coefficients of the analytes in the coatings. The partition coefficient, which is controlled by the chemical and physical properties of the coating materials, determines the inherent selectivity and sensitivity toward analyte molecules. The selection of the coatings is logically determined by the interactions between coating and target analyte molecules, but can also be made through a systematic variation of the coating's properties. The determination of the partition coefficients is only accurate if all contributions to the total measured frequency shifts, deltafs, of the coated QCR can be established. While mass loading is often assumed to be the dominant factor used in determining partition coefficients, viscoelastic effects may also contribute to deltafs. Both the effect of viscoelastic properties and the effect of mass loading on the sensor responses are investigated by using a network analyzer and oscillator circuit and by characterizing the total mechanical impedance of the loaded sensor. Different types of coatings including rubbery and glassy polymers are investigated, and the targeted analytes include classes of polar compounds (methanol), nonpolar compounds (toluene, xylenes), and chlorinated hydrocarbons (trichloroethylene, tetrachloroethylene, etc). It is seen that changes in viscoelastic properties due to analyte sorption may be significant enough to place the sensor in the nongravimetric regime. However, for most applications involving the detection of relatively low concentrations of organic compounds and the use of acoustically thin films, changes in the complex shear modulus of the coatings contribute less than 5% of the total shift in the series resonant frequency, depending on the coating. In that case, the measured deltafs and, hence, the calculated approximate classification and selection of the coatings for operation in a complex solution of water/analyte molecules.

Journal Article↗
PubMed2000

Enterococcal-type glycopeptide resistance genes in non-enterococcal organisms.

Although the emergence of vancomycin-resistant enterococci can be attributed, in part, to the increasing use of vancomycin in clinical practice, and glycopeptide use in animal husbandry, the origins of the enterococcal vancomycin resistance genes are not clear. The vancomycin resistance-associated genes in Enterococcus gallinarum, Enterococcus casseliflavus/flavescens, Lactobacillus spp., Leuconostoc spp., Pediococcus spp., and Erysipelothrix rhusiopathiae, are not the source of the high-level vancomycin resistance-associated genes in enterococci. There are, however, environmental organisms which have been found to have gene clusters homologous to the enterococcal vanA, vanB and vanC gene clusters; these include the biopesticide Paenibacillus popilliae, and, to a lesser extent, the glycopeptide-producing organisms Amycolatopsis orientalis and Streptomyces toyocaensis. Still, the exact sources of the enterococcal vancomycin resistance genes remain a mystery.

Anti-Bacterial Agents↗
PubMed2000

alpha(v)beta(3) integrin induces tyrosine phosphorylation-dependent Ca(2+) influx in pulmonary endothelial cells.

The endothelial alpha(v)beta(3) integrin occurs luminally, where its ligation by soluble agents may induce inflammatory signaling. We tested this hypothesis in bovine pulmonary artery endothelial cell monolayers with the use of vitronectin and cross-linking antibodies to ligate and aggregate the integrin. We quantified the endothelial cytosolic Ca(2+) concentration ([Ca(2+)](i)) according to the Fura 2 ratio imaging method in single cells of confluent monolayers. At baseline, endothelial [Ca(2+)](i) levels remained steady at 86 nmol/L for >20 minutes. Cross-linking of the alpha(v)beta(3) integrin through the sequential exposure of monolayers to anti-alpha(v)beta(3) monoclonal antibody LM609 and secondary IgG resulted in a [Ca(2+)](i) increase of 100% above baseline. This increase commenced in <0.5 minute, peaked in <2 minutes, and decayed to baseline in approximately 5 minutes. Similar responses occurred after the addition of vitronectin (400 microg/mL). In contrast, external Ca(2+) depletion blunted the cross-linking-induced [Ca(2+)](i) increase by 60%, a response that was completely inhibited when the monolayers were also pretreated with thapsigargin. Thus, the [Ca(2+)](i) increase was attributable in part to the release of Ca(2+) from endosomal stores but mostly to Ca(2+) influx across the plasma membrane. Induced aggregation of the alpha(v)beta(3) integrin enhanced tyrosine phosphorylation of phospholipase C-gamma1 and increased the accumulation of inositol-1, 4,5-trisphosphate. Genistein, a broad-spectrum tyrosine kinase inhibitor, abrogated both of these effects, as well as the alpha(v)beta(3)-induced [Ca(2+)](i) increases. We conclude that aggregation of the endothelial alpha(v)beta(3) integrin induces a rapid tyrosine phosphorylation-dependent increase in [Ca(2+)](i). This response may subserve the inflammatory role of alpha(v)beta(3) integrin in blood vessels.

Animals↗