Biomedical subjects

J M Bos

Publications and source records attributed to J M Bos.

11 recordsLinked to original sources

PubMed2001

Cost-effectiveness of HIV screening of patients attending clinics for sexually transmitted diseases in Amsterdam.

OBJECTIVE: To estimate the cost-effectiveness of universal HIV screening of patients attending a clinic for sexually transmitted diseases (STD) in Amsterdam. DESIGN: Cost effectiveness analysis. METHODS: A Bernoulli model for the secondary transmission of HIV was linked with epidemiological data on infection with HIV and other STD in patients attending a STD clinic in Amsterdam from 1991 to 1997. This gave estimates of the number of secondary HIV infections caused by attenders of the STD clinic. Combined with data on the health and monetary benefits of averting HIV infection and costs of HIV screening, we assessed the cost-effectiveness of HIV-screening of attenders of the STD clinic. RESULTS: Increased risk for HIV infection was found in STD clinic attendees infected with other STD. (odds ratio, 2.07). The risk differed for specific STD: the highest odds ratios were found for syphilis and gonorrhoea. Screening of all attendees was estimated at net costs of 82,552 Euro per secondary infection averted. The cost-effectiveness ranges between 680 Euro and 9335 Euro per life-year gained, depending on the value of key parameters used in the model. CONCLUSION: Compared to other interventions in infectious diseases control in the Netherlands, screening of STD clinic attendees for HIV has an acceptable cost-effectiveness.

Ambulatory Care Facilities↗

PubMed2001

Health economics of a hexavalent meningococcal outer-membrane vesicle vaccine in children: potential impact of introduction in the Dutch vaccination program.

The cost-effectiveness of universal vaccination of infants with a new hexavalent meningococcal B outer-membrane vesicle vaccine is projected for The Netherlands by applying decision analysis. The societal perspective is taken and direct and productivity costs (friction costs method) are considered. Future costs and effects are discounted at 4% (base year 1998). In this simulation model, vaccination would prevent 19 deaths and eight cases with severe long-term sequelae per year, rendering 526 additional quality adjusted life years (QALYs) per year. Yearly costs of acute phase of illness due to meningococcal infections in children are estimated at 1,426,634, while the future costs due to sequelae are estimated at 3,801,121 per year. Of all these costs, the vaccination program could prevent 3,334,052 per year. The program costs of meningococcal vaccination are estimated at 11,601,356, resulting in a cost-effectiveness ratio (CER) of 15,721 per QALY. These results are sensitive to the vaccine dose price (conservatively estimated at 10), efficacy, and coverage of meningococcal sero-subtypes.

Bacterial Outer Membrane Proteins↗

PubMed2001

Calcium channel blockers in the management of preterm labor and hypertension in pregnancy.

Calcium channel blockers (CCBs) have the ability to inhibit contractility in smooth muscle cells. CCBs have an already established role in the treatment of non-pregnant hypertension and angina pectoris. Some epidemiological studies found an association between the use of CCBs and an increase in cardiovascular mortality, malignancy, and gastrointestinal bleeding. More recent studies with many more patients and a longer follow-up did not find these associations. In obstetrics CCBs have become increasingly popular for the management of preterm labor and pregnancy-induced hypertensive disorders. Meta-analysis shows that use of nifedipine in comparison with betamimetics is associated with a more frequent successful prolongation of pregnancy in case of preterm labor, resulting in significantly fewer admissions of newborns to the neonatal intensive care unit (NICU), and is associated with a lower incidence of respiratory distress syndrome. No adverse fetal side effects in humans have been reported with the use of nifedipine for obstetric indications. Nifedipine is an effective and safe drug to use when tocolytic therapy is indicated for preterm labor. In preeclampsia nifedipine effectively lowers blood pressure and can be a good alternative for (di) hydralazine.

Breast Feeding↗

PubMed2001

The economics of HIV vaccines: projecting the impact of HIV vaccination of infants in sub-Saharan Africa.

OBJECTIVES: (i) To project vaccine parameters, economic consequences and market size associated with HIV-1 vaccination of infants in sub-Saharan Africa through the Expanded Program on Immunisation (EPI); and (ii) to assess threshold values for price and effectiveness. STUDY DESIGN AND METHODS: Cost-effectiveness analysis using a decision-analysis model linking epidemiological data with economic information. Epidemiological data on the burden of disease of HIV were obtained from the World Health Organization (WHO) and the Joint United Nations Programme on HIV/AIDS. The decision analysis model was constructed using estimates of lifetime chances of HIV infection. To assess threshold values for price and effectiveness, a maximum value for cost effectiveness in developing countries of $US100 was used in the base case. One-way and multivariate sensitivity analysis was performed on relevant parameters, assessing the impact of these parameters on the results of our analysis. In the base case, health benefits and consequences were discounted at a rate of 3%. STUDY PERSPECTIVE: Societal. RESULTS: According to our model, introduction of an HIV-1 vaccine in the EPI would result in the vaccination of 8717112 infants in sub-Saharan Africa per year. This corresponds to the prevention of 1839355 cases of HIV per year, gaining 16461800 disability-adjusted life years (DALYs). The cost-effectiveness ratio of the intervention would be $US3.4 per DALY gained (1998 values) at a vaccine price in the base case of $US5. At the same price the estimated size of the market would be approximately $US44536111 per year. CONCLUSION: If technological and financial problems associated with the development of an HIV vaccine can be solved, HIV vaccination in Africa could be both cost effective and potentially profitable.

AIDS Vaccines↗

PubMed2000

Traffic accident reduction by monitoring driver behaviour with in-car data recorders.

People who are aware of being observed tend to modify their behaviour. This phenomenon could potentially be used to encourage individuals to behave more safely when driving if there were means of providing feedback to the drivers about their behaviour on the road. So-called 'vehicle data recorders' offer such a means of providing behavioural feedback by confronting drivers with their recorded driving actions. A field trial of a 'matched experimental/control group design with intervention' was planned with the objective of investigating whether this feedback mechanism would reduce the number of road traffic accidents in everyday driving conditions. In the study, seven experimental vehicle fleets were involved, which varied widely in terms of the kind of transport sector concerned, the type of vehicles used, and the traffic circumstances in which the vehicles are operated. Each fleet was matched with at least one control vehicle fleet, taking into account those relevant traffic safety characteristics. In total, accident and exposure data were collected for 840 vehicles of which 270 equipped with a recorder. During an observation period representing a total of about 3,100 vehicle years, these vehicles were involved in 1,836 road accidents. Analysis of the effects of the use of data recorders in these fleets resulted in an average estimated accident reduction of some 20%. The analysis shows that the actual savings vary depending on the transport sector involved and on the prior level of the fleet's safety record. Further studies are needed to identify the more promising application of such a use of traffic data recorders as a means of reducing road accidents.

Accidents, Traffic↗

PubMed1999

Using cluster random assignment to measure program impacts. Statistical implications for the evaluation of education programs.

This article explores the possibility of randomly assigning groups (or clusters) of individuals to a program or a control group to estimate the impacts of programs designed to affect whole groups. This cluster assignment approach maintains the primary strength of random assignment--the provision of unbiased impact estimates--but has less statistical power than random assignment of individuals, which usually is not possible for programs focused on whole groups. To explore the statistical implications of cluster assignment, the authors (a) outline the issues involved, (b) present an analytic framework for studying these issues, and (c) apply this framework to assess the potential for using the approach to evaluate education programs targeted on whole schools. The findings suggest that cluster assignment of schools holds some promise for estimating the impacts of education programs when it is possible to control for the average performance of past student cohorts or the past performance of individual students.

Bias↗

PubMed1999

Economic evaluation of influenza vaccination. Assessment for The Netherlands.

OBJECTIVE: The objective of this study was to determine the costs associated with influenza and the cost effectiveness (net costs per life-year gained) of influenza vaccination in The Netherlands. DESIGN AND SETTING: The economic evaluation comprised a cost-of-illness assessment and a cost-effectiveness analysis, both of which were conducted from the healthcare perspective in The Netherlands. The modelling framework for the economic evaluation linked epidemiological aspects of influenza (e.g. incidence, mortality, years of life lost) to vaccination coverage and healthcare resource use. Healthcare resource use was specified for hospitalisations, general practitioner visits and drugs. INTERVENTION: The intervention assessed in the cost-effectiveness analysis was influenza vaccination. MAIN OUTCOME MEASURES AND RESULTS: The costs of influenza were estimated to be 31 million euros (EUR) for the influenza season 1995/96 in The Netherlands (EUR1 approximately $US1.1). For the extended programme in 1997/98, i.e. all elderly people, the cost-effectiveness ratio was estimated at EUR1820 per life-year gained. Sub-group analysis demonstrated that the programme had a more favourable cost effectiveness among the chronically ill elderly population (cost saving) than among the rest of the elderly population (EUR6900 per life-year gained). CONCLUSION: Influenza vaccination has a cost-effectiveness ratio that is better than or comparable to that of other implemented Dutch programmes in the prevention of infectious diseases.

Cost-Benefit Analysis↗

PubMed1996

Enhanced thrombin sensitivity of a factor VIII-heparin cofactor II hybrid.

Generation of thrombin at a site of vascular injury is a key event in the arrest of bleeding. In addition to the conversion of fibrinogen into the insoluble fibrin, thrombin can initiate a number of positive and negative feedback mechanisms that either sustain or down-regulate clot formation. We have modulated the thrombin sensitivity of human blood coagulation factor VIII, an essential cofactor in the intrinsic pathway of blood coagulation. We have substituted an acidic region of factor VIII corresponding to amino acid sequence Asp712-Ala736 by amino acid sequence Ile51-Leu80 of the thrombin inhibitor heparin cofactor II. Functional analysis of the resulting factor VIII-heparin cofactor II hybrid, termed des-(868-1562)-factor VIII-HCII, revealed an increase in procoagulant activity as measured in a one-stage clotting assay. Incubation of purified des-(868-1562)-factor VIII-HCII with different amounts of thrombin showed that this protein was more readily activated by thrombin when compared with des-(868-1562)-factor VIII, a control protein lacking amino acid sequence Ile51-Leu80 of heparin cofactor II. This was manifested by an increase in the second order rate constant of activation by thrombin for des-(868-1562)-factor VIII-HCII (12.0 +/- 0.48 x 10(6) M-1 s-1) compared with des-(868-1562)-factor VIII (1.77 +/- 0.21 x 10(6) M-1 s-1). Our data suggest that amino acid sequence Ile51-Leu80 of heparin cofactor II endows factor VIII with increased sensitivity towards thrombin which results in accelerated clot formation.

Amino Acid Sequence↗

PubMed1976

Large-scale use of freeze-dried smallpox vaccine prepared in primary cultures of rabbit kidney cells.

A lyophilized smallpox vaccine made from infected monolayer cultures of primary rabbit kidney cells was used together with a calf lymph vaccine in a field trial in Lombok, Indonesia, in 1973. About 60 000 children below 15 years of age were vaccinated: some 50 000 with the tissue culture vaccine and about 10 000 with calf lymph vaccine. Similar results were obtained with both vaccines in primary vaccinees and in revaccinees as regards the take rate, pock reactions, and serious secondary reactions.

Adolescent↗

PubMed1972

Cutaneous responses to smallpox revaccination with calf lymph and the effect of fluorocarbon purification of the vaccine.

For several years the routine smallpox revaccination procedures at a central inoculation unit were arranged to assess the relation between vaccine titre (pock count) and success. Calf lymph batches were applied, diluted and undiluted, over a log titre range of 7.0-9.8. The dose-effect relationship did not appear to fit a linear equation on a log-probit scale, except in the lower part of the titre range. Plotted on this scale, the take rates of nearly all vaccine specimens of the required strength (> 10(8) PFU/ml) were lower than anticipated by linear extrapolation from low titres. Differences between batches were noted. These findings relate to pulp processing without purification. Fluorocarbon extraction of the calf skin harvest resulted in a 4-fold increase of vaccine volume with commensurate virus dilution; it also gave clearly higher take rates than parallel nonpurified vaccine specimens, whether at original strength or at 4-fold dilution.

Animals↗

PubMedDate not supplied

A voice-enabled, structured medical reporting system.

Kurzweil Applied Intelligence received a research grant from the National Institute of Standards and Technology (NIST) Advanced Technology Program to develop a prototype voice-enabled, structured medical reporting system. In typical usage, the physician dictates to the system, which then uses automatic speech recognition and medical knowledge bases to produce a structured report. This report can then be formatted and viewed on a computer screen, stored in databases of patient information, transmitted to other systems, used to support outcome studies, or viewed on a Web browser. The output reports are structured according to two standard, platform-independent formats: SGML and CORBA. These formats represent the data in a way that can be read by both computers and humans, and efficiently communicated to a wide range of databases and communications protocols.

Information Storage and Retrieval↗