Biomedical subjects
Publications and source records attributed to J Main.
We report an increased prevalence of renal disease, particularly glomerulonephritis, in Upper Weardale, UK. Silica exposure during fluorspar mining and processing is a likely cause.
Hepatitis C shares common routes of infection with hepatitis B (HBV) and the human immunodeficiency virus (HIV). It is, therefore, not surprising to find that some patients with HCV are co-infected with either HIV and/or HBV. Until recently, the effects of HIV on HCV infection have not been investigated--sadly patients with HIV died long before their liver disease became problematic. However, the development of successful therapies for HIV have led to dramatic improvements in life expectancy for patients infected with this virus and in these patients, with well controlled HIV, it is becoming clear that hepatitis C may lead to the early onset of advanced liver disease. The optimal treatment for these patients is unknown but it seems likely that combination antiviral therapy will be required. The effects of HBV on HCV are also beginning to be investigated and, again, it is clear that co-infection leads to more aggressive liver disease with the two viruses interacting in poorly defined ways to increase the rate of hepatic fibrosis. Management of combined HCV/HBV infection is still under investigation and will probably involve combination therapy.
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In a patient with previously documented myocardial infarction, we assessed myocardial perfusion by using power contrast imaging and a newer intravenous echo contrast agent. The images were captured and stored digitally, and various image processing algorithms were used to assess myocardial perfusion. An apical perfusion defect was clearly visualized, and it correlated with radionuclide findings.
BACKGROUND: Previous studies of bereavement in primary care have tended to concentrate on the attitudes of general practitioners (GPs) to bereavement support and little has been documented on the views of patients. AIM: To establish the role, content, and value of a protocol designed to help the newly bereaved by examining the experiences and expectations of a group of bereaved patients within a single general practice, with a view to developing patient care within this area. METHOD: A qualitative approach was adopted using a semi-structured questionnaire, data collection, and analysis consistent with the principles of grounded theory. Patients were approached by letter and those who agreed to take part in the study were interviewed at home. RESULTS: Many of those interviewed expected some form of contact from their GP after bereavement, although the nature of the contact they would have liked varied. The majority would have appreciated a letter of sympathy and none would have objected to it. Over half expressed some form of dissatisfaction either with their GP or with the hospital. Quality of information giving and communication affected bereavement outcomes for some. The role of the GP was examined and patients responded positively to practical suggestions to improve bereavement care. CONCLUSIONS: Bereavement support was seen to be an important part of the GP role by the majority of those interviewed. As a result recommendations have been made for a protocol to support the newly bereaved.
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Evaluation of the cost-effectiveness of antibiotic regimens has become an essential part of drug selection for pharmacists and physicians. However, these evaluations can be complicated, time-consuming, and, if the data used are not based on local conditions, misleading. The computer program Dare to Compare 98 was developed to provide an analysis of empiric antibiotic regimens. The Infectious Disease Challenge portion of the program lists the commonly identified pathogens in specific infectious diseases. The Antibiogram Susceptibility Reports section generates susceptibility reports based on local antibiogram data or data from institutions nationwide that have similar demographic profiles. Susceptibility information is combined with cost data in the Quality/Cost Index section. Comparison of the quality and cost index values allows the user to determine which regimens provide the optimal microbiologic activity and cost values for treatment of a particular infectious disease based on local data. Thus Dare to Compare 98 can help pharmacists and physicians evaluate antibiotic regimens and their suitability for inclusion in formularies and disease-management algorithms.
Densities of states weighted with the diagonal matrix elements of two operators A and B, i.e., rho(A,B)(E)= summation operator(n) delta(E-E(n)), cannot, in general, be written as a trace formula, and therefore no simple extension of semiclassical trace formulas is known for this case. However, from the high resolution analysis of quantum spectra in the semiclassical regime we find strong evidence that weighting the delta functions in the quantum mechanical density of states with the product of diagonal matrix elements, , is equivalent to weighting the periodic orbit contributions in the semiclassical periodic orbit sum with the product of the periodic orbit means, (p) (p), of the classical observables A and B. Results are presented for the hydrogen atom in a magnetic field for both the chaotic and near-integrable regime, and for the circle billiard.
Semiclassical spectra weighted with products of diagonal matrix elements of operators A(alpha), i.e., g(alphaalpha')(E)= summation operator(n) /(E-E(n)), are obtained by harmonic inversion of a cross-correlation signal constructed of classical periodic orbits. The method provides highly resolved semiclassical spectra even in situations of nearly degenerate states, and opens the way to reducing the required signal lengths to shorter than the Heisenberg time. This implies a significant reduction of the number of orbits required for periodic orbit quantization by harmonic inversion.
The quantitative contributions of a mixed phase space to the mean characterizing the distribution of diagonal transition matrix elements and to the variance characterizing the distributions of nondiagonal transition matrix elements are studied. It is shown that the mean can be expressed as the sum of suitably weighted classical averages along an ergodic trajectory and along the stable periodic orbits. Similarly, it is shown that the values of the variance are well reproduced by the sum of the suitably weighted Fourier transforms of classical autocorrelation functions along an ergodic trajectory and along the stable periodic orbits. The illustrative numerical computations are done in the framework of a hydrogen atom in a strong magnetic field, for three different values of the scaled energy.
BACKGROUND: Data from randomised studies are lacking on the value of interventional procedures in the management of atheromatous renal artery stenosis. This randomised prospective trial compared the effects on blood pressure (BP) and renal function of percutaneous transluminal angioplasty vs medical therapy in hypertensive patients with both unilateral and bilateral disease. METHODS: A total of 135 eligible patients were identified, of whom 55 (44%) were randomised. Eligible patients had sustained hypertension, with a minimum diastolic BP of 95 mm Hg on at least two anti-hypertensive drugs. Renal artery stenosis was defined by renal angiography as at least 50% stenosis in the affected vessel. All patients were observed during an initial 4-week run-in period on a fixed drug regimen and subsequent changes measured from this 4-week baseline. RESULTS: Blood pressure fell during the run-in period in all groups. In patients with bilateral renal artery stenosis randomised to angioplasty, a statistically significant (P<0.05) fall in BP was observed at latest follow-up (range 3-54 months). The mean fall in BP at latest follow-up in the angioplasty group, corrected for the medical group response, was 26/10 mm Hg. In patients with unilateral renal artery stenosis, no statistically significant or clinically important differences in outcome were observed between the two groups. No significant differences or trends in serum creatinine were observed between or within any group during follow-up. Major outcome events (death, myocardial infarction, heart failure, stroke, dialysis) were similar in the angioplasty and medical groups during follow-up. In the 40/135 patients undergoing angioplasty, serious or potentially serious complications attributable to the procedure were observed in 11 patients, bleeding at the arterial site (8 patients) being the most frequent. CONCLUSIONS: In hypertensive patients with atheromatous renal artery stenosis, percutaneous renal angioplasty results in a modest improvement in systolic BP compared with medical therapy alone. This benefit was confined to patients with bilateral disease. No patient was 'cured', renal function did not improve, and intervention was accompanied by a significant complication rate.
Lamivudine, a novel cytosine analogue, exhibits potent antiviral activity against hepatitis B virus (HBV) in vitro and in vivo. The standard HBV DNA hybridization assay used in phase II clinical studies has a low sensitivity, the detection limit of HBV DNA levels being approximately 10(7) genome equivalents per ml (geq ml-1). In this work we used a semiquantitative polymerase chain reaction (PCR) assay (detection limit approximately 10(3) geq ml-1) to determine HBV DNA levels during a 24-week study of lamivudine in 51 stable chronic hepatitis B patients who were positive for hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg). Patients were randomly allocated to receive oral doses of 25, 100 or 300 mg lamivudine once daily. At week 24 the median serum concentration of HBV DNA had fallen from 10(8) to 10(4) geq ml-1, a 4-log median reduction. A trend towards more profound suppression of viral replication with an increased dose of lamivudine was observed. After 12 weeks of therapy, 12% of patients had an HBV DNA level that was undetectable in the PCR assay; this increased to 26% after 24 weeks, while in an additional 20% of patients, HBV DNA decreased to the level of detection of the PCR assay. We conclude that a 24-week course of lamivudine decreases serum HBV DNA to the level of PCR detection in 46% of patients. Such additional viral suppressive activity with higher doses and more protracted lamivudine may be of clinical utility prior to liver transplantation. Further studies are needed to define the degree of virus suppression required in clinical practice, and methods are required to increase the efficacy of virus suppression.
Three hundred million individuals worldwide have persistent hepatitis B virus infection with 1-2 million hepatitis B virus-associated deaths per year, and an estimated 1% of the world's population are infected with hepatitis C virus. Recent advances in molecular biology and host responses have led to an increased understanding of hepatitis B and C virus disease and new potential targets for therapy.
Interferon-alpha therapy has proved effective for up to 40% of patients with adult-acquired chronic hepatitis B virus (HBV) infection and for 20-25% of those with chronic hepatitis C virus (HCV) infection. Nucleoside analogues, such as lamivudine and famciclovir, are showing promise as antiviral agents for chronic HBV and the combination of interferon-alpha and ribavirin is proving to be successful therapy for 40-50% of patients with chronic HCV. In this article we review current therapy and discuss future strategies of the therapy of chronic viral hepatitis.
OBJECTIVE: To assess the attendance, outcome, compliance with treatment, and response to interferon alfa in patients with chronic hepatitis C who attended during 1995 and were treated according to a biopsy based algorithm. DESIGN: Retrospective audit of all patients with chronic hepatitis C attending outpatient clinics over one year. SETTING: The liver unit at a London teaching hospital. SUBJECTS: 255 patients with chronic hepatitis C. MAIN OUTCOME MEASURES: Patient survival, attendance, and compliance with diagnostic and therapeutic regimens. Response to interferon alfa treatment, based on loss of viraemia three months after cessation of treatment. RESULTS: A large proportion of patients (39%) with newly diagnosed chronic hepatitis C infection do not want to undergo further investigation. Of those patients who do attend for further treatment, a large proportion with severe hepatic fibrosis (42%) do not want to undergo currently available treatment. The response rate to interferon (21%) in treated patients was similar to that previously reported in a trial setting. There was no significant difference in response rates in patients with or without severe fibrosis not amounting to cirrhosis. In patients with cirrhosis there was a high incidence of hepatocellular carcinoma (18%) over a follow up period of 20 months. CONCLUSION: Current strategies aimed at investigating and treating patients with chronic hepatitis C are not acceptable to a large proportion of patients. Many patients with cirrhosis related to hepatitis C infection develop hepatic neoplasms, and management strategies to deal with this problem are urgently required.
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