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Biomedical subjects

K Fischer

Publications and source records attributed to K Fischer.

At least 37 records · Page 2Linked to original sources
PubMed2004

Analysis of Sarcoptes scabiei finds no evidence of infection with Wolbachia.

The endosymbiont Wolbachia has been detected in a range of filarial nematodes and parasitic mites and is known to affect host reproductive compatibility and potentially evolutionary processes. PCR of Wolbachia surface protein (wsp), ftsZ and 16SrRNA genes from individual Sarcoptes scabiei mites obtained from a series of individual hosts, and database searches of an S. scabiei var. hominis EST library failed to detect Wolbachia genes. Therefore, Wolbachia appears not to be involved in the genetic subdivision observed between varieties of host-associated S. scabiei or, involved in the inflammatory disease pathogenesis of scabies unlike its activity in filarial infection.

Animals↗
PubMed2004

Genetic and environmental sources of egg size variation in the butterfly Bicyclus anynana.

By dividing families of the tropical butterfly, Bicyclus anynana, among different larval (including early pupal) and adult (including late pupal) temperatures, we investigate the genetic and environmental effects on egg size. Both sources of variation affected egg size to similar extents. As previously found in other arthropods, egg size tended to increase at lower temperatures. Our data suggest that the plastic response in egg size can be induced during the pupal stage. Females reared as larvae at the same high temperature tended to lay larger eggs when transferred to a lower temperature, either as prepupae or pupae, compared to those remaining at the high temperature. Additionally, females reared as larvae at different temperatures, but maintained at the same temperature from the early pupal stage onwards, laid larger eggs after larval growth at a low temperature. Heritability estimates for egg size were about 0.4 (parent-offspring regression) and 0.2 (variance component estimates using the full-sib families). Although there seemed to be some variation in the plastic response to temperature among families, genotype-environment interactions were nonsignificant.

Adaptation, Physiological↗
PubMed2004

Hepatitis C infection in children with haemophilia: a pilot study.

Many haemophilia patients were infected with hepatitis C virus (HCV) in childhood after transfusion with inadequately or non-virus inactivated clotting factor products. Limited information is available on the clinical course of HCV infection in children. To assess the clinical consequences of hepatitis C in these young patients we performed a pilot study of 31 patients with haemophilia, infected with HCV before the age of 13. Current median age was 20 years. Nineteen (61%) patients had chronic hepatitis C, whereas the remaining 12 patients spontaneously cleared HCV. The median duration of infection was 17 years. Among patients chronically infected with HCV, an enlarged liver and/or spleen on ultrasound was present in 59%, whereas 63% had abnormal aminotransferases and/or gamma-GT values. In conclusion, 39% of the patients infected in childhood cleared HCV spontaneously. The majority of the patients with chronic hepatitis C had ultrasound and/or laboratory abnormalities and these findings may be associated with the presence of chronic liver disease.

Adolescent↗
PubMed2004

Dose and outcome of care in haemophilia--how do we define cost-effectiveness?

Severe haemophilia (factor [F]VIII/FIX activity < 0.01 IU mL(-1)) is characterized by repeated haemarthroses resulting in severe arthropathy in adulthood. In 1958, Professor Nilsson in Sweden introduced prophylactic infusions with clotting factor concentrates at regular intervals in order to maintain clotting factor levels above 0.01 IU mL(-1) and to prevent bleeding. Since then, evidence of the long-term beneficial effects of prophylactic treatment for severe haemophilia has been increasing and it has become the recommended treatment strategy for children with severe haemophilia by both the World Health Organization and the US National Hemophilia Foundation Medical and Scientific Advisory Committee. However, the implementation of this recommendation has been hampered by issues of cost and venous access. The high costs of prophylaxis have largely prevented its use in major parts of the world. The question therefore is whether the current models of replacement of clotting factor concentrates, while certainly being effective, are also optimal. Can the data on outcome at different levels of factor replacement be used to assess their cost-effectiveness?

Adolescent↗
PubMed2003

Prophylaxis for severe haemophilia: clinical and economical issues.

Patients with severe haemophilia are treated either in case of bleeds only (on demand), or with regular infusions of clotting factor to prevent bleeds (prophylaxis). The introduction of prophylaxis has been hampered by issues of cost and viral safety. In order to compare results and treatment cost of different treatment strategies in adults, three cohorts of patients with severe haemophilia (born 1970-1980) were compared. 106 French patients were treated on demand, 49 Dutch patients were treated with intermediate dose prophylaxis, and 24 Swedish patients were treated with high dose prophylaxis. The annual number of joint bleeds, and the radiological Pettersson score were used to compare outcome, annual clotting factor consumption was used to compare costs. Prophylaxis reduced bleeds and arthropathy: patients treated on demand had a median of 11.5 joint bleeds/year and a median Pettersson score of 16 points, for intermediate dose prophylaxis median bleeds were 2.8 and Pettersson score was 7 points, and for high dose prophylaxis median bleeds were 0.5 joint bleeds and Pettersson score was 4 points. All differences were statistically significant, except the Pettersson scores in both prophylactic regimens. Treatment cost was only increased for high dose prophylaxis: mean clotting factor consumption was 1612 IU kg-1 yr-1 for on demand treatment, 1488 IU kg-1 yr-1 for intermediate dose prophylaxis, and 4012 IU kg-1 yr-1 for high dose prophylaxis. In young adults, the cost of intermediate dose prophylaxis is similar, but outcome is better than for on demand treatment. The cost of high dose prophylaxis is twofold higher, further improving outcome only slightly.

Adolescent↗
PubMed2003

Comparing outcomes of different treatment regimens for severe haemophilia.

Published retrospective reports from France, the Netherlands and Sweden were analysed for data relating to the long-term outcomes (primarily the development of arthropathy) of three regimens for the management of severe haemophilia: on-demand treatment, intermediate-dose prophylaxis and high-dose prophylaxis. The mean annual consumption of factor concentrate was also compared. These data indicate that both prophylaxis regimens resulted in significantly improved long-term outcomes, as assessed by pain, clinical and radiological assessment scores. At the same time, the most recently reported annual factor consumption levels of these young adult patients are comparable in the on-demand and intermediate-dose prophylaxis cohorts, suggesting that the improvement in long-term clinical outcomes and reduced risk of arthropathy may lead to reduced factor consumption in adult patients who received early prophylactic therapy.

Adolescent↗
PubMed2003

Health-related quality of life as outcome parameter in haemophilia treatment.

Health-related quality of life (HRQoL) is increasingly used as an outcome parameter in haemophilia treatment. Currently, only generic HRQoL instruments are used, as disease-specific instruments for haemophilia are not available. The most widely used generic instruments are the descriptive SF-36 questionnaire and the EQ-5D questionnaire for assessment of utilities, ie preference-based HRQoL. Results of both instruments show significant correlation. All haemophilia prophylaxis studies using HRQoL as an outcome report a decreased HRQoL compared with the general population, a positive effect of prophylactic treatment and a negative effect of age. Generic instruments for measuring HRQoL are able to pick up differences between groups of patients with haemophilia and enable us to make comparisons across diseases. However, in order to establish the optimal treatment strategy for severe haemophilia, further information is needed on the long-term effects of different strategies on HRQoL. In addition, haemophilia-specific HRQoL instruments should be developed in order to provide detailed information for adjustment and evaluation of treatment in individual patients.

HIV Infections↗
PubMed2003

Consensus perspectives on prophylactic therapy for haemophilia: summary statement.

Participants in an international conference on prophylactic therapy for severe haemophilia developed a consensus summary of the findings and conclusions of the conference. In the consensus, participants agreed upon revised definitions for primary and secondary prophylaxis and also made recommendations concerning the need for an international system of pharmacovigilance. Considerations on starting prophylaxis, monitoring outcomes, and individualizing treatment regimens were discussed. Several research questions were identified as needing further investigation, including when to start and when to stop prophylaxis, optimal dosing and dose interval, and methods for assessment of long-term treatment effects. Such studies should include carefully defined cohorts, validated orthopaedic and quality-of-life assessment instruments, and cost-benefit analyses.

Consensus Statements as Topic↗
PubMed2002

Effects of prophylactic treatment regimens in children with severe haemophilia: a comparison of different strategies.

Both Sweden and the Netherlands have a long experience with primary prophylaxis in children with severe haemophilia. In these countries it has been offered to all children for the last 3-4 decades. In Sweden prophylaxis is generally started at an earlier age with a higher dosage and frequency than in the Netherlands. Patients in the Netherlands receive a more individually tailored regimen, with prophylaxis now started after the first one or two joint bleeds and dosages are increased when breakthrough bleeds occur. The current study evaluated the effect prophylaxis on long-term outcomes and the consumption of clotting factor concentrates in Dutch and Swedish cohorts. Our results show that the orthopaedic outcome in the oldest groups of patients from Sweden and the Dutch cohorts were comparable, although the Swedish patients used twice as much clotting products per year. In the youngest patients, joint status is very good and further follow-up is necessary to demonstrate the benefits of either strategy. In conclusion, more individually tailored regimens aimed at preventing bleeding prevent joint damage in children with severe haemophilia, while clotting factor consumption is about half of that in previously described regimens.

Adolescent↗
PubMed2002

Pilot testing of the 'Haemo-QoL' quality of life questionnaire for haemophiliac children in six European countries.

In a multinational working group, an instrument (Haemo-QoL) to assess quality of life in children/adolescents with haemophilia and their parents has been developed. In co-operation with haemophilia treatment centres in six European countries, approximately 10 children/adolescents with haemophilia per country and their parents were asked to participate in the pilot-testing. Both self-reported and parent-reported questionnaires were provided for two age-groups of children (4-16 years). Medical data was collected from physicians from patient files. Answers to open questions from participants (58 children and 57 parents) confirmed the content of 116 of the preliminary items. Cognitive debriefing revealed that the majority of the Haemo-QoL was rated favourably, but 29 questions were recommended to be omitted and several items to be reformulated. Preliminary psychometric testing of the revised 77 item questionnaire in the same sample showed acceptable reliability and validity, which will be examined in a subsequent study with a larger patient sample.

Adolescent↗
PubMed2002

Prophylactic treatment for severe haemophilia: comparison of an intermediate-dose to a high-dose regimen.

A multicentre study was performed in Sweden and the Netherlands, comparing effects of two prophylactic regimens in 128 patients with severe haemophilia, born 1970-90. 42 Swedish patients (high-dose prophylaxis), were compared with 86 Dutch patients (intermediate-dose prophylaxis). Patients were evaluated at the date of their last radiological score according to Pettersson. Annual clotting factor consumption and bleeding frequency were registered for a period of three years before evaluation. Patients in the high-dose group were younger at evaluation (median 15.2 vs. 17.9 years), started prophylaxis earlier (median 2 vs. 5 years), and used 2.19 times more clotting factor kg-1 year-1. Patients treated with high-dose prophylaxis had fewer joint bleeds (median 0.3 year-1 vs. 3.3 year-1) and the proportion of patients without arthropathy as measured by the Pettersson score was higher (69% vs. 32%), however, the age-adjusted difference in scores (median 0 points vs. 4 points) was small and at present not statistically significant. Clinical scores and quality of life were similar. These findings suggest that, compared with intermediate-dose prophylaxis, high-dose prophylaxis significantly increases treatment costs and reduces joint bleeds over a period of 3 years, but only slightly reduces arthropathy after 17 years of follow-up.

Adolescent↗
PubMed2002

Prophylactic versus on-demand treatment strategies for severe haemophilia: a comparison of costs and long-term outcome.

A multicentre study was performed to compare clotting factor use and outcome between on-demand and prophylactic treatment strategies for patients with severe haemophilia. Data on treatment and outcome of 49 Dutch patients with severe haemophilia, born 1970-80, primarily treated with prophylaxis, were compared with those of 106 French patients, who were primarily treated on demand. Dutch patients received intermediate dose prophylaxis, for a median duration of 12.7 years. Patients primarily treated with prophylaxis had fewer joint bleeds per year (median 2.8 vs. 11.5), a higher proportion of patients without joint bleeds (29% vs. 9%), lower clinical scores (median 2.0 vs. 8.0), and less arthropathy as measured by the Pettersson score (median 7 points vs. 16 points). Mean annual clotting factor use was equal at 1,488 +/- 783 IU kg-1 year-1 (mean +/- standard deviation) for patients primarily treated with prophylaxis and 1,612 +/- 1,442 IU kg-1 year-1 for patients primarily treated on demand. These findings suggest that, compared with a primarily on-demand treatment strategy, a primarily prophylactic treatment strategy leads to better outcome at equal treatment costs in young adults with severe haemophilia.

Adult↗