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Biomedical subjects

A M Patel

Publications and source records attributed to A M Patel.

At least 19 recordsLinked to original sources
PubMed2004

Appropriate consent and referral for general anaesthesia - a survey in the Paediatric Day Care Unit, Barnsley DGH NHS Trust, South Yorkshire.

BACKGROUND: In November 1998 the General Dental Council introduced guidelines for dental practitioners when referring a patient for general anaesthesia (GA). The practitioner is required to explain the risks associated with GA and the alternatives, give a detailed medical history and a clear justification for providing GA in the letter of referral. METHOD: A survey was administered on 202 parents or guardians, which aimed to investigate whether they felt that their dental practitioners had advised them of any risks of GA prior to referral. A record was also made if any reasons were given for the provision of GA in the letter of referral. RESULTS: The majority of the parents or guardians (66%) felt that they were not informed of any of the risks of GA and 25% felt that they were. From the letters of referral, 37% contained a reason for GA and 63% did not give any reason or justification for GA. CONCLUSION: There is evidence that referring practitioners do not adequately explain the risks of the anaesthetic to parents or guardians of children undergoing GA. There is also a lack of clear justification in the letters of referral for providing GA. PRACTICE IMPLICATION: It is essential that the alternatives and the risks of GA are discussed and if GA is still required, a clear justification should be contained in the letter of referral as part of informed consent. More importantly the referring practitioner should keep a contemporaneous record of this, preferably with a signature from the parent or guardian on agreement of referral.

Adolescent↗
PubMed2003

Tuberculosis-related deaths in Queensland, Australia, 1989-1998: characteristics and risk factors.

OBJECTIVE: To review factors associated with TB-related deaths in Queensland, Australia. DESIGN: Review of data for TB patients dying before treatment completion; demographic and clinico-pathological comparison of TB-related deaths with other notified patients after exclusion of losses to follow-up; matched case-control study of co-morbid conditions in patients under 75 years. RESULTS: Of 1003 tuberculosis cases notified between 1989 and 1998, 127 died before completing anti-tuberculosis treatment. Tuberculosis was the main cause of death in 53 cases, a significant contributor in 34 and unrelated in 40, giving a TB-related case fatality rate of 8.7%. Decedents were older on average, except among indigenous Australians (IA); age-adjusted case fatality rates did not vary significantly among ethnic groups. Pulmonary and disseminated TB, coexistent malnutrition, renal disease and liver disease increased the risk of death. HIV infection increased the risk of dying, but was uncommon among Queensland cases. Neither sputum smear positivity nor drug resistance was associated with risk of death. Twenty-five TB-related deaths occurred before diagnosis, with significant overrepresentation of IA. Most had serious co-morbidities and symptomatic pulmonary disease. Seven socially or geographically isolated decedents did not access documented health care for tuberculosis. CONCLUSIONS: Fatality was related to older age, disseminated disease and co-morbidity. Dying undiagnosed from tuberculosis was associated with respiratory co-morbidity and social and geographical isolation, mainly in the aged in low TB risk populations and in IA in remote regions.

Adolescent↗
PubMed2002

Torsional response and stiffening of individual multiwalled carbon nanotubes.

We report on the characterization of torsional oscillators which use multiwalled carbon nanotubes as the spring elements. Through atomic-force-microscope force-distance measurements we are able to apply torsional strains to the nanotubes and measure their torsional spring constants, and estimate their effective shear moduli. The data show that the nanotubes are stiffened by repeated flexing. We speculate that changes in the intershell mechanical coupling are responsible for the stiffening.

Journal Article↗
PubMed2001

Hypersensitivity pneumonitis: current concepts and future questions.

Hypersensitivity pneumonitis (extrinsic allergic alveolitis) caused by inhaled allergens can progress to disabling or even fatal end-stage lung disease. The only truly effective treatment is early recognition and control of exposure. Although patients produce antibody exuberantly, the immunopathogenesis involves cellular immunity--notably, CD8(+) cytotoxic lymphocytes, multinucleate giant cell granulomas, and ultimately interstitial fibrosis. Many causative agents have been recognized in occupational dusts or mists, but most current new cases arise from residential exposure to pet birds (pigeons and parakeets), contaminated humidifiers, and indoor molds. The symptoms and physical findings are nonspecific. Serum IgG containing high titers of specific antibody to the offending antigen is elevated. Pulmonary function tests show restrictive and diffusion defects with hypoxemia, especially after exercise. Occasionally, small airways disease causes obstruction. Radio-graphic changes vary according to the stage of the disease and are best evaluated by means of high-resolution computed tomography. In typical cases, the history of a known exposure and the presence of a characteristic interstitial lung disease with serologic confirmation of IgG antibody to the offending antigen suffice for diagnosis. In more obscure cases, observation of changes after a natural environmental exposure, bronchoalveolar lavage, and lung biopsy might be indicated. Among the many questions that remain are the following: What is the prevalence of hypersensitivity pneumonitis and how often is it the cause of chronic interstitial fibrosis? What is the long-term prognosis? Why do most individuals exposed to these antigens develop a vigorous antibody response whereas only a few develop the disease? How does exposure to endotoxin and cigarette smoking affect the disease? To answer these questions, standardized and validated clinical laboratory immunochemical tests are needed, in addition to a systematic approach to diagnosis, classification of disease severity, risk assessment, and management. This review is limited to the disease caused by airborne allergens and focuses on its immunopathogenesis, eliciting agents, clinical manifestations, diagnosis, management, and prognosis.

Air Pollutants↗
PubMed2001

Investigation of some commercially available spacer devices for the delivery of glucocorticoid steroids from a pMDI.

Five commercially available spacers were investigated to determine their influence on the percentage of drug retained in the spacer device, percentage fine particle fraction (FPF), percentage deposited in the induction port, mass median aerodynamic diameter (MMAD), and geometric standard deviation (GSD). Betamethasone valerate (BMV) and triamcinolone acetonide (TAA) were used as model drugs in the pressurized metered dose inhaler (pMDI) formulations containing the propellant HFA 134a. The BMV was dissolved in an ethanol/HFA 134a system, and the TAA was suspended in HFA 134a using ethanol as a dispersing agent. The metering chamber volume of the valve was either 50 microl or 150 microl. The spacer devices investigated included the ACE, Aerochamber, Azmacort, Easivent, and Ellipse spacers. Each spacer device was attached to an Andersen Cascade Impactor powered by a vacuum pump. Cascade impaction data were used to derive the percentage drug deposited in the induction port, MMAD, GSD, and FPF. The BMV particles emitted from the spacers were finer than the TAA particles because the dissolved drug precipitated as the cosolvent evaporated. The TAA particles had significantly larger MMADs because many undissolved drug particles were contained within each droplet following actuation. After evaporation of the liquid continuous phase, the suspended drug aggregated to form larger agglomerates than those particles precipitated from the BMV pMDI solution droplets. The addition of a spacer device lowered the MMAD to less than 4.7 microm for particles from both the BMV pMDI solution and the TAA pMDI suspension. The addition of a spacer device also lowered the percentage drug deposited in the induction port. The FPF was significantly increased when a spacer device was used. The MMAD significantly decreased when a spacer device was added for the two model drugs when using the 150-microl metering valves, but the difference was not statistically significant when the 50-microl valves were used (P < .05). The GSD was not influenced by the use of a spacer device. The use of a spacer device will enhance pMDI therapy by reducing the amount of drug deposited in the oropharyngeal region, which will lead to fewer instances of local and systemic side effects. In addition, the spacer devices investigated will allow a higher dose of drug to reach the deep lung, which may permit the use of lower dosage regimens with increased therapeutic efficacy.

Administration, Inhalation↗
PubMed2001

Using the Internet in the management of asthma.

The ultimate goals of managing asthma are to eliminate death, prevent or promptly treat exacerbations, and maximize the quality of life and health status of patients. Current strategies include appropriate education, trigger control, and timely access to effective pharmacotherapy and follow-up. Internet-based technologies have emerged as potentially powerful tools to enable meaningful communication and proactive partnership in care for various medical conditions. The main types of Internet-based applications for asthma management include remote monitoring and feedback between health professionals and their patients; online education and marketing for either patients or professionals; networking and collaborative research; and administrative oversight through policy making, planning, and decision support. With increased understanding of integrated disease management and the technostructural as well as psychodynamic issues related to Internet use, further refinement and evolution of the Internet and related technologies may drastically improve the way we monitor, educate, treat, and establish policies for this global problem while attending to individual or local community needs. This review presents a conceptual overview of the current challenges and use of the Internet for improving asthma management through timely and tailored education and appropriate access to health care expertise.

Asthma↗
PubMed2000

Treatment of underlying atrial fibrillation: paced rhythm obscures recognition.

OBJECTIVES: The purpose of this study was to evaluate the rate of recognition of atrial fibrillation (AF), use of warfarin and prevalence of cerebrovascular accident (CVA) in paced versus unpaced patients during admission to a tertiary care teaching hospital. BACKGROUND: The presence of AF underlying a continuously paced rhythm may be under recognized and result in a lower rate of anticoagulation and higher incidence of CVA. METHODS: The identification of AF on 12 lead electrocardiogram (ECG) and telemetry, "optimal use" of anticoagulants that is, warfarin or aspirin, when warfarin is contraindicated and history of prior CVA was studied in three groups: 1) group A with continuously paced rhythm on ECG and telemetry (n = 30), 2) group B with intermittently paced rhythm on ECG and telemetry (n = 59), and 3) group C with persistent AF and no permanent pacemaker (n = 50). RESULTS: The identification and documentation of AF was significantly lower in the continuously paced group A (20%) versus the intermittently paced group B (44%). Both groups A and B were substantially lower than unpaced controls. "Optimal use" of anticoagulants was significantly lower in group A (40%) compared with groups B (78%) and C (72%) but was not different between groups B and C. The prevalence of prior CVA was not significantly different between the three groups. CONCLUSIONS: All ECGs in patients with paced rhythm should be examined closely for underlying AF to prevent under-recognition and under-treatment with anticoagulants.

Aged↗
PubMed2000

Prevalence, pathophysiology, and treatment of patients with asthma and gastroesophageal reflux disease.

About one third of the US adult population experiences symptoms of gastroesophageal reflux on a monthly basis. Asthma is present in about 5% of the same population. This article reviews and summarizes the literature in the following areas: (1) prevalence of gastroesophageal reflux disease (GERD) in asthmatic patients based on clinical symptoms, endoscopic esophagitis, and 24-hour ambulatory esophageal pH recordings; (2) proposed pathophysiologic mechanisms linking the 2 diseases; and (3) medical and surgical treatment trial results of antireflux therapy for asthmatic patients. Asthmatic patients appear to have an increased prevalence of GERD symptoms and 24-hour esophageal acid exposure. The clinical management of these patients remains controversial. Common management approaches to GERD in asthmatic patients include medical therapy with a proton pump inhibitor and/or antireflux surgery, which improve asthma symptoms in many patients but minimally affect pulmonary function.

Adult↗
PubMed1999

Attachment of periosteal grafts to articular cartilage with fibrin sealant.

Favorable results using fibrin sealants in vascular surgery and soft tissue reconstruction have prompted investigation of these biologic adhesives for orthopedic applications. One important recent application was as a sealant for periosteal grafts applied to defects in articular surfaces, a procedure that contained injected chondrocytes cultured in vitro. The low and variable adhesive strength of autologous fibrin substances prompted our investigation of allogeneic fibrin. An in vitro test method was developed to investigate the use of a fibrin sealant for attaching periosteal (bovine) patches to articular cartilage (bovine). Dermis-dermis (porcine) adhesion also was evaluated. In tests of the periosteum-to-cartilage bond performed in a physiological environment, we determined the effects of the following variables on the adhesive shear strength: set time, source of fibrinogen (bovine versus human), and fibrinogen concentration. A specially designed test rig was developed to avoid nonshear force components. Adhesive shear strength increased with fibrin set time for both fibrinogen concentrations and sources (p <.03). The 30-min set time yielded data with less variance than the 5-min set time in all cases except with the higher human fibrinogen concentration (50-80 mg/mL). While there was a trend at each set time towards greater shear strength with increased protein concentration (50-80 mg/mL versus 25-40 mg/mL), only the 5-min trial of the bovine product provided a significant advantage (p <.006). There was no significant difference in adhesive strength between the fibrin products produced with human and bovine fibrinogen. The periosteum-cartilage adhesive strengths obtained in our model were comparable to values recorded for the dermis-dermis bonding. The greater strength at the 30-min set time suggests that a certain time period of joint immobilization might be beneficial in procedures in which grafts are glued to articular cartilage. This study has shown that adhesive strengths achieved with fibrin glues in treating skin wounds also can be achieved in the attachment of periosteal grafts to articular cartilage.

Animals↗
PubMed1999

Concerted action of cytosolic Ca2+ and protein kinase C in receptor-mediated phospholipase D activation in Chinese hamster ovary cells expressing the cholecystokinin-A receptor.

Receptor-mediated activation of phosphatidylcholine phosphatidohydrolase or phospholipase D (PLD) was studied in Chinese hamster ovary (CHO) cells expressing the cholecystokinin-A (CCK-A) receptor. Cells were labelled with [3H]myristic acid for 24 h and PLD-catalysed [3H]phosphatidylethanol formation was measured in the presence of 1% (v/v) ethanol. Cholecystokinin-(26-33)-peptide amide (CCK8) increased PLD activity both time- and dose-dependently. Maximal activation of protein kinase C (PKC) with 1 microM PMA or sustained elevation of the cytosolic free Ca2+ concentration ([Ca2+]i) with 1 microM thapsigargin increased PLD activity to 50% and 70% of the maximal value obtained with CCK8 respectively. The stimulatory effects of CCK8, PMA and thapsigargin were abolished in cells in which PKC was downregulated or inhibited by chelerythrine. PMA/Ca2+-stimulated PLD activity was absent in a homogenate of PKC-downregulated cells but could be restored upon addition of purified rat brain PKC. CCK8-induced PLD activation was inhibited by 90% in the absence of external Ca2+, demonstrating that receptor-mediated activation of PKC in itself does not significantly add to PLD activation but requires a sustained increase in [Ca2+]i. Taken together, the results presented demonstrate that, in CHO-CCK-A cells, receptor-mediated PLD activation is completely dependent on PKC, but that the extent to which PLD becomes activated depends largely, if not entirely, on the magnitude and duration of the agonist-induced increase in [Ca2+]i.

Alkaloids↗
PubMed1999

Consultation for asthma: results of a generalist survey.

BACKGROUND: There are few studies that examine referral patterns for asthma and few studies that examine the referring physicians' reasons for consultation. OBJECTIVE: The purpose of this study was to survey generalist physicians on their referral patterns for adult patients with asthma. METHODS: We mailed a questionnaire to all the staff (faculty) in the Department of Family Medicine and the Division of Community Internal Medicine at the Mayo Clinic in Rochester, Minnesota. There were 37 completed questionnaires (18 family medicine and 19 internal medicine) out of a total of 58 for a response rate of 64%. The survey asked what were reasons for consultation, whether allergists or pulmonologists were preferred, and the characteristics of a good consultation. RESULTS: We asked respondents to indicate "how often you consult a specialist for an adult asthma patient" for a variety of clinical indications. The percentage responding "always" (for the top five indications) were if the patient requests one (46%), for allergen immunotherapy (38%), for single life-threatening attack (27%), for allergy testing (14%), and for steroid-dependent asthma or poorly controlled asthma (11%). Twenty-seven percent of respondents generally consulted allergists only, 22% generally consulted pulmonologists only, 3% indicated both, while 46% had no preference. Respondents did express a preference for a pulmonologist when the reported reason for the consultation was diagnosis of asthma uncertain, chronic cough, asthma in smoker, exercise training, or for an allergist when the reported reason for consultation was allergy evaluation or immunotherapy. The respondents indicated that the top six characteristics of a good consultation were the following: clear recommendations, clinically appropriate recommendations, high patient satisfaction, including recommendations for future management scenarios, including educational content in the consultation, and calling the referring physician before requesting a secondary consultation. CONCLUSIONS: These results suggest that while consultation occurs often for severe or uncontrolled asthma, some asthma patients who may benefit from consultation may not be seeing the specialist. There were no systematic preferences for consultations with allergists versus pulmonologists for asthma although for some clinical indications pulmonologists or allergists were favored. Referring physicians value clear, clinically appropriate recommendations.

Adult↗
PubMed1998

U73122 and U73343 inhibit receptor-mediated phospholipase D activation downstream of phospholipase C in CHO cells.

The aminosteroid 1-(6-¿[17beta-3-methoxyestra- 1,3,5(10)-trien- 17-yl]-amino¿hexyl)- 1H-pyrrole-2,5-dione (U73122) and its inactive analogue 1-(6-¿[17beta-3-methoxyestra-1,3,5(10)-trien- 17-yl]-amino¿hexyl-2,5-pyrrolidine-dione (U73343) are widely used to study the involvement of G protein-coupled 1-phosphatidylinositol-phosphodiesterase, or phospholipase C, in receptor-mediated cell activation. The present work shows that both aminosteroids inhibit cholecystokinin-(26-33)-peptide amide (CCK-8)-induced phospholipase D activation equipotently in Chinese hamster ovary cells expressing the cholecystokinin-A receptor (CHO-CCK(A) cells). In addition, the two aminosteroids virtually completely inhibited thapsigargin- and 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced phospholipase D activation. Since the latter two drugs mimic inositol 1,4,5-trisphosphate-mediated Ca2+ mobilisation and 1,2-diacylglycerol-mediated protein kinase C activation. respectively, this suggests that both U73122 and U73343 act downstream of phospholipase C to inhibit receptor-mediated phospholipase D activation. U73122, but not U73343. effectively inhibited both TPA/Ca2+-stimulated phospholipase D activation and TPA/phosphatidylserine-stimulated protein kinase C activation in a homogenate of CHO-CCK(A) cells. The data presented suggest that U73122 may act at the level of protein kinase C to inhibit activation of phospholipase D. The exact site of action of U73343 is presently unknown.

Animals↗
PubMed1997

Practical considerations for managing asthma in adults.

Asthma is a common, chronic inflammatory disorder of the airways associated with pronounced health and economic consequences. Consistent and effective education that promotes an active partnership with patients remains the cornerstone for managing asthma. Identification and control of asthma triggers, regular monitoring of lung function, and adequate pharmacologic therapy are three other critical components. In this article, we describe several practical considerations for developing a collaborative, multidisciplinary approach to asthma care that emphasizes patient education and strengthens the partnership between patients and health-care professionals.

Activities of Daily Living↗
PubMed1997

Tribological evaluation of oxidized zirconium using an articular cartilage counterface: a novel material for potential use in hemiarthroplasty.

Problems with total joint replacement that have surfaced in recent years have made reconsideration of more conservative hip reconstructive procedures compelling. Moreover, procedures such as hemiarthroplasty might benefit from newly developed materials that could provide more favourable tribological performance when employed as a counterface for articulation with articular cartilage. The objective of this study was to evaluate the tribology of a new biomaterial, oxidized zirconium, with articular cartilage in a laboratory test apparatus. Oxidized zirconium components are produced by oxidizing the zirconium alloy to form a relatively thick (7 microns), adherent, abrasion-resistant ceramic surface. We found that the coefficient of friction of bovine articular cartilage rubbed against oxidized zirconium was lower than with cobalt-chromium alloy control surfaces, and that there was a trend toward less wear with oxidized zirconium. A defined layer of degraded tissue was found on the surface of the articular cartilage specimens, providing some indication of the mechanism of wear. Results of this study warrant further investigation of oxidized zirconium as the bearing surface for hemiarthroplasty.

Alloys↗
PubMed1996

Amplification and expression of EMS-1 (cortactin) in head and neck squamous cell carcinoma cell lines.

Amplification of chromosome 11q13 DNA sequences is detected in approximately 30% of primary head and neck squamous cell carcinomas (HNSCC). The amplified region includes genes for cyclin D1, hst-1, int-2, and more recently, ems-1. Ems-1 encodes an 80/85kd cytoskeletal associated protein termed cortactin, which has been shown to bind F-actin and is a pp60src substrate. We investigated 16 HNSCC cell lines for ems-1 DNA amplification and gene expression by western blotting and immunofluorescence using mAb 4F11. Amplification of ems-1 DNA was detected in 8/16 (50%) cell lines and was related directly to over-expression of cortactin by western blotting and immunofluorescence. Western blotting detected both forms of cortactin, p80 and p85, at equal intensity. Immunofluorescent staining revealed low levels of cortactin localized to the cytoplasm and surface membrane in normal bronchial epithelial cells and tumor cell cultures with single copy ems-1 DNA. In contrast, tumor cell cultures with ems-1 DNA amplification demonstrated intense, homogeneous cortactin cytoplasmic staining. These results suggest that overexpression of p80/85 may be a useful marker to identify 11q13 amplification, a molecular alteration correlated with the presence of lymph node metastasis in head and neck cancer.

Carcinoma, Squamous Cell↗