[Computer-assisted diagnosis of rare diseases]. / Computerunterstützte Diagnosefindung bei seltenen Erkrankungen.

To establish a comprehensive diagnosis is by far the most challenging task in a physician's daily routine. Especially rare diseases place high demands on differential diagnosis, caused by the high number of around 8000 diseases and their clinical variability. No clinician can be aware of all the different entities and memorizing them all is impossible and inefficient. Specific diagnostic decision-supported systems provide better results than standard search engines in this context. The systems FindZebra, Phenomizer, Orphanet, and Isabel are presented here concisely with their advantages and limitations. An outlook is given to social media usage and big data technologies. Due to the high number of initial misdiagnoses and long periods of time until a confirmatory diagnosis is reached, these tools might be promising in practice to improve the diagnosis of rare diseases.

Lifibrol enhances the low density lipoprotein apolipoprotein B-100 turnover in patients with hypercholesterolemia and mixed hyperlipidemia.

Lifibrol (4-(4'-tert-butylphenyl)-1-(4'carboxyphenoxy)-2-butanol), a new hypocholesterolemic drug, effectively reduces total cholesterol (CH), low density lipoprotein (LDL)-CH, and apolipoprotein (apo) B in experimental animals and in humans. The impact of Lifibrol on the metabolism of apoB-100 containing lipoproteins in patients with hyperlipoproteinemia using endogenous labeling with stable isotopes is examined. Kinetic studies were performed in four male hypercholesterolemic individuals (type IIa) before and on treatment with 450 mg of Lifibrol daily for 4 weeks, and in five male individuals suffering from mixed hyperlipidemia (type IIb) before and on therapy for 12 weeks. Kinetic parameters were estimated by multicompartmental modeling. Lifibrol therapy reduced total CH by 16% (P = 0.012) in all patients, increased triglycerides (TG) by 11% (not significant) in type IIa patients and decreased TG by 34% (P = 0.059) in type IIb patients. During Lifibrol therapy, LDL apoB-100 concentrations decreased by 19% (P = 0.011) in all patients. The decrease in LDL apoB concentrations with Lifibrol therapy was due to an overall increase (75%, P = 0.006) of the fractional catabolic rates (FCR) of LDL apoB. This increase was partially attenuated by a 33% increase in LDL apoB production rate (PR) (P = 0.041). The overall production of apoB increased only slightly. Our data suggest that the major mechanism by which Lifibrol lowers LDL-CH is an increase in receptor-mediated catabolism of LDL rather than a decrease in hepatic apoB production.

An interactive Web site providing major histocompatibility ligand predictions: application to HIV research.

EpiMatrix/HIV, a tool that is currently available on the World Wide Web, enables researchers to screen HIV proteins for potential MHC ligands. We have performed a comparison of EpiMatrix predictions to 158 published allotype-specific HLA-associated peptides (MHC ligands) derived from 133 proteins. The top 10 ranked EpiMatrix predictions for each of the 158 HLA allotype-protein pairs were selected for comparison with these published ligands. EpiMatrix correctly identified 134 of 158 published ligands (85%). The algorithm is now available for use by the HIV research community at the URL http:/(/)www.EpiMatrix.com/HIV.

[Secondary disorders of lipid metabolism, metabolic syndrome and familial combined hyperlipidemia]. / Sekundäre Fettstoffwechselstörungen, metabolisches Syndrom und familiär kombinierte Hyperlipidämie.

Secondary hyperlipoproteinemias are found in connection with other primary organic diseases. Typical examples are those seen with diabetes mellitus, liver and kidney diseases. In addition there are changes induced by hormonal dysfunctions such as hypothyroidism, by the use of oral contraceptives or in postmenopausal women. During pregnancy there is a physiological transient increase in lipoproteins. In addition to primary organic diseases there are a number of exogenous factors such as obesity, malnutrition and alcohol abuse causing hyperlipidemia. The relation between hypertension and hyperlipidemia described as familial dyslipidemic hypertension is less well known. Obesity, hypertension, dyslipidemia, hyperuricemia and impaired glucose tolerance are the basic conditions of the metabolic syndrome. Familial combined hyperlipidemia is a genetically determined, dyslipidemic syndrome with a high prevalence among patients with coronary artery disease and stroke. As there are some links between familial combined hyperlipidemia and secondary hyperlipoproteinemias, this disease entity is discussed together in this paper. Familial combined hyperlipidemia is metabolically, genetically and by this on a molecular level closely linked to familial dyslipidemic hypertension as well as the metabolic syndrome. The exact mechanism of this disease is currently unknown.

[Lipid lowering therapy for primary prevention of coronary heart disease--pro lipid lowering therapy]. / Lipidsenkende Therapie zur Primärprävention der koronaren Herzkrankheit--Pro lipidsenkende Therapie.

The high rate of coronary artery disease (CAD) mortality needs preventive intervention. Several studies have documented the effectiveness of LDL-cholesterol lowering in CAD primary prevention. The West of Scotland Prevention Study resulted in risk reduction by about one third through LDL-cholesterol lowering. The data indicate that specifically patients at high risk benefit from lipid reduction. High risk patients have besides high LDL-cholesterol one or more additional risk factors such as family history of premature coronary artery disease, hypertension, smoking, low HDL-cholesterol or diabetes. Therapy primarily aims at life style changes, secession of smoking and weight reduction as well as dietary changes to achieve LDL-cholesterol levels of 115-175 mg/dl (3-4.5 mmol/L), depending on the individual risk constellation. This strategy allows to reduce the number of patients needed to treat in order to prevent one CAD event (56 in isolated hypercholesterolemia) to 14-24 in high risk persons, approaching the number (n = 13) known for effective lipid lowering in secondary prevention of coronary heart disease. Given the fact that only one third of patients suffering from a myocardial is likely to survive the first year after the event, its time for physicians to identify patients at high risk for coronary artery disease. This LDL-cholesterol lowering in primary prevention is an important and successful approach in preventive medicine. The high risk strategy for coronary primary prevention has shown to be cost effective more or at least similar to the treatment of hypertension.

Quantification of apolipoprotein A-IV in human plasma by immunonephelometry.

We developed a nephelometric procedure for determining concentrations of human plasma apolipoprotein (apo) A-IV. Results obtained correlate well with those measured by an established electroimmunodiffusion assay (r = 0.98; n = 56). Intra- and interassay CVs were 2.4% and 2.0%, respectively, indicating excellent precision and reproducibility. Various conditions of sample treatment, such as adequate storage, freezing, and thawing, did not affect results significantly. However, keeping samples at room temperature for 4 days led to a slight increase in measured values. Preincubation with a cholesterinesterase-detergent mixture abolished interference from triglyceride-rich lipoproteins, allowing assay of samples containing triglycerides as great as 10 g/L. The assay is easily applicable to clinical laboratories for routine diagnostic use, as shown with hypertriglyceridemic plasmas and samples with a broad range of apo A-IV concentrations.

[Pharmacoeconomic evaluation of pravastatin in the secondary prevention of coronary heart disease in patients with average cholesterol levels. An analysis for Germany based on the CARE study]. / Pharmakoökonomische Bewertung von Pravastatin in der Sekundärprävention der koronaren Herzkrankheit bei Patienten mit durchschnittlichen Cholesterinwerten. Eine Analyse für Deutschland auf der Grundlage der CARE-Studie.

Those people who are to decide about health care systems are increasingly forced to identify unnecessary costs and achieve savings in health care. Especially for diseases with high prevalence like illnesses of the heart and the circulatory system preventive measures are very important. This economic analysis tries to clarify whether the secondary-preventive application of the HMG-CoA reductase-inhibitor pravastatin is, apart from the clinical benefit, economically justified in patients suffering from coronary heart disease with average cholesterol levels. In the case of this study, the underlying type of economic evaluation was an incremental cost-effectiveness analysis. The outcome was defined as costs per life-year saved. This retrospective study is based on the results of the CARE (Cholesterol And Recurrent Events) study which has been published elsewhere [21]. When calculating costs we took into account the perspective of 3rd party payers (public health insurance) in Germany. The calculation of cost-effectiveness was carried out for the whole study population in CARE as well as for all patients aged 60 or more years in the CARE study. This was done because the different groups vary by the numbers of avoided myocardial infarctions, strokes and loss of life years. Netcosts for pravastatin therapy, i.e. drug costs for pravastatin minus costs for avoided events, were about 9.54 Mio DM (referring to 1,000 patients treated for a period of 5 years). Net-costs for patients aged 60 or more years were 8.18 Mio DM. The effectiveness was defined as the number of life years saved and amounted to 216 years of life saved (YOLS) in the overall study group. For patients aged 60 or more years we found that 358 years were saved. The costs per life years saved (i.e. the net-costs of pravastatin therapy divided through the number of life years saved) turned out to be 44,000 DM per person in the study group. For patients over 60 the costs were 23,000 DM. Lipid-lowering with pravastatin in the secondary prevention of coronary heart disease in Germany is cost-effective. In those patients aged 60 or more yeas the use of pravastatin is even more cost-effective than in all patients included in the CARE study.

[Cost effectiveness of pravastatin in secondary coronary prevention in patients with myocardial infarct or unstable angina in Germany. An analysis on the basis of the LIPID trial]. / Kosteneffektivität von Pravastatin in der koronaren Sekundärprävention bei Patienten mit Myokardinfarkt oder instabiler Angina pectoris in Deutschland. Eine Analyse auf der Grundlage der LIPID-Studie.

Secondary coronary prevention with lipid lowering drugs has become a major issue in health policy formulation due to the large upfront investment in drug therapy. The recently completed LIPID trial with pravastatin in secondary prevention immediately raise the question whether pravastatin might be cost-effective in Germany. We conducted a cost-effectiveness analysis from the perspective of third party payers. The following costs were included in the analysis: daily treatment costs of pravastatin, non-fatal myocardial infarction, coronary bypass operations and stroke. Life years gained were obtained by applying the declining exponential approximation of life expectancy. All calculations were standardized to 1,000 treated patients. The net costs of treating 1,000 patients (i.e. drug costs minus the costs of sequelae and interventions) are DM 8.4 Mio. In addition, a total of 405 life years may be saved through treatment. The corresponding cost-effectiveness of pravastatin treatment is DM 20,674,-(DM 17,314,-, discounted by 3% p.a.).

Origin of the pandemic 1957 H2 influenza A virus and the persistence of its possible progenitors in the avian reservoir.

H2N2 influenza A viruses caused the Asian pandemic of 1957 and then disappeared from the human population 10 years later. To assess the potential for similar outbreaks in the future, we determined the antigenicity of H2 hemagglutinins (HAs) from representative human and avian H2 viruses and then analyzed the nucleotide and amino acid sequences to determine their evolutionary characteristics in different hosts. The results of longitudinal virus surveillance studies were also examined to estimate the prevalence of avian H2 isolates among samples collected from wild ducks and domestic poultry. Reactivity patterns obtained with a large panel of monoclonal antibodies indicated antigenic drift in the HA of human H2 influenza viruses, beginning in 1962. Amino acid changes were clustered in two regions of HA1 that correspond to antigenic sites A and D of the H3 HA. By contrast, the antigenic profiles of the majority of avian H2 HAs were remarkably conserved through 1991, resembling the prototype Japan 57 (H2N2) strain. Amino acid changes were distributed throughout HA1, indicating that antibodies do not play a major role in the selection of avian H2 viruses. Phylogenetic analysis revealed two geographic site-specific lineages of avian H2 HAs: North American and Eurasian. Evidence is presented to support interregion transmission of gull H2 viruses. The human H2 HAs that circulated in 1957-1968 form a separate phylogenetic lineage, most closely related to the Eurasian avian H2 HAs. There was an increased prevalence of H2 influenza viruses among wild ducks in 1988 in North America, preceding the appearance of H2N2 viruses in domestic fowl. As the prevalence of avian H2N2 influenza viruses increased on turkey farms and in live bird markets in New York City and elsewhere, greater numbers of these viruses have come into direct contact with susceptible humans. We conclude that antigenically conserved counterparts of the human Asian pandemic strain of 1957 continue to circulate in the avian reservoir and are coming into closer proximity to susceptible human populations.

Activation by malaria antigens renders mononuclear cells susceptible to HIV infection and re-activates replication of endogenous HIV in cells from HIV-infected adults.

We have tested the hypothesis that activation of T cells by exposure to malaria antigens facilitates both de novo HIV infection and viral reactivation and replication. PBMC from malaria-naive HIV-uninfected European donors could be productively infected with HIV following in vitro stimulation with a lysate of Plasmodium falciparum schizonts and PBMC from malaria-naive and malaria-exposed (semi-immune) HIV-positive adults were induced to produce higher levels of virus after stimulation with the same malaria extract. These findings suggest that effective malaria control measures might con-tribute to reducing the spread of HIV and extending the life span of HIV-infected individuals living in malaria endemic areas.

Rapid determination of apolipoprotein E phenotypes from whole plasma by automated isoelectric focusing using PhastSystem and immunofixation.

The influence of the genetic apolipoprotein (apo) E isoforms on human plasma lipoproteins is well established. There is, however, still a need for a phenotyping procedure applicable in laboratories not specialized in lipid research. To this end, we developed a rapid, automated electrophoresis method for apoE phenotyping. Either self-made or commercially available precasted gels can be used. Fresh or frozen samples corresponding to 0.1 microliter of plasma are applied automatically after lipid extraction in a urea-containing buffer onto the gel and isoelectric focusing is carried out for 45 min. Thereafter, apoE bands are precipitated by specific polyclonal antibodies and visualized by automated silver staining. The method is reliable, easily and quickly performed, and not restricted to specialized laboratories.

[Identification of elevated carbohydrate-deficient transferrin (CDT) serum level as transferrin (Tf)-D-variant by means of isoelectric focusing]. / Identifizierung eines mittels Immunturbidimetrie nach Anionenaustausch-Chromatographie erhöhten Carbohydrate-Deficient-Transferrin-(CDT-)Serumspiegels als Transferrin (Tf)-D-Variante.

Many studies have shown carbohydrate-deficient transferrin (CDT) to be a sensitive and specific marker of chronic alcohol abuse. We present the case of a 23-year-old, healthy professional soccer player who caused a car accident due to alcohol consumption. Several CDT test results were elevated above the laboratory reference range and were considered to be caused by alcohol intake at a level commensurate with misuse and thus license reapplication was refused. In addition, assuming chronic alcohol abuse, the young man suffered from increasing social isolation. He was finally referred to our out-patient clinic for further evaluation on the assumption of a liver disease. Since chronic alcohol consumption was denied, and there was no evidence of liver disease, a qualitative characterization of the transferrin isoforms was performed. Isoelectric focusing of serum transferrin revealed a pattern atypical for chronic alcohol intake but detected a genetically determined transferrin (Tf)-D-variant. The changed amino acid sequence caused an overlapping of transferrin isoforms with different degrees of sialylation, thus revealing false-positive serum CDT values. Determination of this Tf-D-variant heterozygosity resulted in his social rehabilitation and license reinstatement. Thus, where the evidence for alcohol dependency is either uncertain or uncorroborated, qualitative isoelectric focusing of transferrin is a useful method for analyzing unexplained CDT elevations, thus increasing the value of CDT as a marker for chronic alcoholic abuse.

Prediction of well-conserved HIV-1 ligands using a matrix-based algorithm, EpiMatrix.

This preliminary study was undertaken to identify new human leucocyte antigens (HLA) ligands from human immunodeficiency virus type 1 (HIV-1) which are highly conserved across HIV-1 clades and which may serve to induce cross-reactive cytotoxic T lymphocytes (CTLs). EpiMatrix was used to predict putative ligands from HIV-1 for HLA-A2 and HLA-B27. Twenty-six peptides that were both likely to bind and also highly conserved across HIV-1 strains in the Los Alamos HIV sequence database were selected for binding assays using the T2 stabilization assay. Two peptides that were also highly likely to bind (for A2 and B27, as determined by EpiMatrix) and well conserved across HIV-1 strains, and had previously been described to bind in the published literature, were also selected to serve as positive controls for the assays. Ten new major histocompatibility complex (MHC) ligands were identified among the 26 study peptides. The control peptides bound, as expected. These data confirm that EpiMatrix can be used to screen HIV-1 protein sequences for highly conserved regions that are likely to bind to MHC and may prove to be highly conserved HIV-1 CTL epitopes.

[Adrenomyeloneuropathy. A frequent cause of Addison's disease]. / Adrenomyeloneuropathie. Eine häufige Ursache des Morbus Addison.

Adrenomyeloneuropathy (AMN) is a "milder form" of adrenoleukodystrophy with a X-linked inheritance. Abnormal catabolism of the very long-chain fatty acids (VLCFA) results in Addison's disease and spastic paraparesis. The VLCFA concentration was measured in 23 of 26 patients with Addison's disease (mean age 48.5 [20-75] years) being treated at the University Hospital Marburg during May, 1991. The concentration was elevated in four of the 12 men with the disease, while it was within normal limits in the 11 women. Only two patients had paraparesis-like neurological deficits. This finding suggests that AMN is not as rare as has been supposed. It is recommended that the concentration of VLCFA be measured in all patients with Addison's disease, because an increase could have important consequences.

Lipoprotein (a), low-density, intermediate-density lipoprotein, and blood pressure in a young male population.

Both hypercholesterolemia and hypertension are risk factors for atherosclerotic vascular disease, and elevated cholesterol levels occur more frequently than expected in patients with hypertension. Elevated levels of intermediate-density lipoproteins (IDL) and low-density lipoproteins (LDL) were shown to be atherogenic, and LDL, comprising the major cholesterol-carrying fraction in human plasma, are structurally related to lipoprotein (a)[Lp(a)], a further risk factor for atherosclerosis. In the present study we investigated 200 male employees (mean age 26 +/- 7 years) to determine whether the relationship of IDL and Lp(a) to systemic blood pressure is similar to the reported correlations between total and LDL cholesterol and systemic blood pressure. To this end blood pressure was measured several times in each individual, and lipids, lipoprotein-cholesterol, apolipoprotein B (apo B), and Lp(a) were determined in fasting serum. IDL cholesterol and apo B, the main protein component of IDL and LDL correlated with blood pressure. However, levels of Lp(a) correlated neither with systolic or diastolic blood pressure nor with lipoprotein cholesterol, body weight, or age. Although IDL and Lp(a) are considered lipoprotein risk factors for atherosclerosis, levels of Lp(a), unlike IDL, are not related to blood pressure, body weight, or age. Our data suggest different metabolic and pathophysiological mechanisms of the risk factors, IDL, LDL, and Lp(a).