Alcohol-induced metabolomic differences in humans.

Alcohol consumption is one of the world's major risk factors for disease development. But underlying mechanisms by which moderate-to-heavy alcohol intake causes damage are poorly understood and biomarkers are sub-optimal. Here, we investigated metabolite concentration differences in relation to alcohol intake in 2090 individuals of the KORA F4 and replicated results in 261 KORA F3 and up to 629 females of the TwinsUK adult bioresource. Using logistic regression analysis adjusted for age, body mass index, smoking, high-density lipoproteins and triglycerides, we identified 40/18 significant metabolites in males/females with P-values <3.8E-04 (Bonferroni corrected) that differed in concentrations between moderate-to-heavy drinkers (MHD) and light drinkers (LD) in the KORA F4 study. We further identified specific profiles of the 10/5 metabolites in males/females that clearly separated LD from MHD in the KORA F4 cohort. For those metabolites, the respective area under the receiver operating characteristic curves were 0.812/0.679, respectively, thus providing moderate-to-high sensitivity and specificity for the discrimination of LD to MHD. A number of alcohol-related metabolites could be replicated in the KORA F3 and TwinsUK studies. Our data suggests that metabolomic profiles based on diacylphosphatidylcholines, lysophosphatidylcholines, ether lipids and sphingolipids form a new class of biomarkers for excess alcohol intake and have potential for future epidemiological and clinical studies.

Supervised machine learning techniques for the classification of metabolic disorders in newborns.

MOTIVATION: During the Bavarian newborn screening programme all newborns have been tested for about 20 inherited metabolic disorders. Owing to the amount and complexity of the generated experimental data, machine learning techniques provide a promising approach to investigate novel patterns in high-dimensional metabolic data which form the source for constructing classification rules with high discriminatory power. RESULTS: Six machine learning techniques have been investigated for their classification accuracy focusing on two metabolic disorders, phenylketo nuria (PKU) and medium-chain acyl-CoA dehydrogenase deficiency (MCADD). Logistic regression analysis led to superior classification rules (sensitivity >96.8%, specificity >99.98%) compared to all investigated algorithms. Including novel constellations of metabolites into the models, the positive predictive value could be strongly increased (PKU 71.9% versus 16.2%, MCADD 88.4% versus 54.6% compared to the established diagnostic markers). Our results clearly prove that the mined data confirm the known and indicate some novel metabolic patterns which may contribute to a better understanding of newborn metabolism.

Prevalence of markers of hepatitis B in the adult German population.

The prevalence of hepatitis B virus markers was investigated in 5305 individuals considered to be representative for the adult German population. After adjustment of the data according to the age and sex distribution in the whole German population an anti-HBc prevalence of 8.71% (95% confidence interval, 7.94-9.48%) and an HBsAg carrier rate of 0.62% (95% confidence interval, 0.40-0.84%) were calculated. Anti-HBc prevalence increased with age from 4.12% in the youngest group to 15.66% in the 61-70-year-old. The percentage of HBsAg carriers showed a maximum of 1.12% in the 41-50-year-old individuals and decreased significantly in the older age groups. 1.40% (95% confidence interval, 1.08-1.72%) of individuals had anti-HBc only. There was a trend to higher rates of this pattern in males than in females; a significantly higher percentage of persons with anti-HBc only was found in anti-HBc-positive individuals below 31 years than in older individuals. Five participants with anti-HBc only (7.7%, or about 0.1% of the whole population) showed HBV-DNA despite the absence of HBsAg. 3.1% of anti-HBc positive individuals where also positive for anti-HCV, that was significantly higher than the percentage of anti-HCV-positives among persons without any HBV marker (0.46%). This study provides a comprehensive picture of the current hepatitis B situation in Germany, showing new data especially on the distribution of HBsAg in the general population and on the subgroup of individuals with anti-HBc only.

High genetic variability of the group-specific a-determinant of hepatitis B virus surface antigen (HBsAg) and the corresponding fragment of the viral polymerase in chronic virus carriers lacking detectable HBsAg in serum.

Chronic carriers of hepatitis B virus (HBV) usually show hepatitis B surface antigen (HBsAg) in their sera, which is considered the best marker for acute and chronic HBV infection. In some individuals, however, this antigen cannot be detected by routine serological assays despite the presence of virus in liver and peripheral blood. One reason for this lack of HBsAg might be mutations in the part of the molecule recognized by specific antibodies. To test this hypothesis, the HBV S gene sequences were determined of isolates from 33 virus carriers who were negative for HBsAg but showed antibodies against the virus core (anti-HBc) as the only serological marker of hepatitis B. Isolates from 36 HBsAg-positive patients served as controls. In both groups, a considerable number of novel mutations were found. In isolates from individuals with anti-HBc reactivity only, the variability of the major hydrophilic loop of HBsAg, the main target for neutralizing and diagnostic antibodies, was raised significantly when compared with the residual protein (22. 6 vs 9.4 mutations per 1000 amino acids; P<0.001) and with the corresponding region in the controls (22.6 vs 7.5 exchanges per 1000 residues; P<0.001). A similar hypervariable spot was identified in the reverse transcriptase domain of the viral polymerase, encoded by the same nucleotide sequence in an overlapping reading frame. These findings suggest that at least some of the chronic low-level carriers of HBV, where surface antigen is not detected, could be infected by diagnostic escape mutants and/or by variants with impaired replication.

Sensitive and accurate quantitation of hepatitis B virus DNA using a kinetic fluorescence detection system (TaqMan PCR).

The laboratory diagnosis of hepatitis B virus (HBV) infection is based mainly on serological assays. Yet the detection and quantitation of viral DNA is necessary when addressing directly the question of infectivity or when monitoring the viral load during therapy. Standard hybridization assays allow for exact quantitation, but their sensitivity is limited to 10(5)-10(6) viral genomes per ml of serum. The most sensitive tests for HBV DNA are nested PCR systems, which recognize virtually one molecule of the target DNA per reaction. However, these assays only provide very coarse quantitative statements. To take advantage of both methods, a new assay for HBV DNA is described based on the commercial TaqMan system. This assay is capable of quantifying HBV DNA from the theoretical lower limit up to 10(10) genome equivalents per ml of serum and, thus, covers the complete range of naturally occurring states of infections. The method was calibrated on the basis of serial plasmid dilutions and compared with a well-established nested PCR system. More than 100 HBV positive sera and serial dilutions of the Eurohep standard for both ad and ay subtypes were analyzed. The assay reliably detected all HBV positive samples. It shows minimal run-to-run deviations, allows for quantitation that covers eight orders of magnitude, and finally, completely avoids the risk of cross-contamination by PCR products. Thus, this technique combines the sensitivity of PCR amplification and the quantitation potential of hybridization tests and it is time efficient and safer.

Characterization of a human pancreatic secretory trypsin inhibitor mutant binding to Legionella pneumophila as determined by a quartz crystal microbalance.

We describe the isolation from a large phagemid library of a human pancreatic secretory trypsin inhibitor (hPSTI) mutant that binds to Legionella pneumophila. To gain further insight into the binding kinetics of the isolated hPSTI mutant, an immunosensing system based on a quartz crystal microbalance (QCM) was used. In contrast to ELISA procedures, k(on) and k(off) rates could be derived from the QCM sensograms. Thus, it is possible to characterize specific intermolecular interactions between proteins and phages isolated from large phage display libraries by QCM.

A novel deletion mutant of hepatitis B virus surface antigen.

HBsAg is the most important serological marker for acute or chronic hepatitis B. Nevertheless, there are reports of HBsAg-negative virus carriers, either with anti-HBc as the only marker for hepatitis B virus (HBV) infection or even positive for anti-HBs and anti-HBc. We report isolates from a patient, in which a deletion in the HBs-gene was associated with persisting viremia in the presence of anti-HBs. The 62-year-old female, infected most likely by her husband, had detectable markers of chronic active hepatitis B, such as HBsAg, HBeAg, and anti-HBc-IgM, for 2 years. The patient then seroconverted to anti-HBs, although HBeAg and anti-HBc-IgM remained detectable. At this time, semiquantitative polymerase chain reaction showed about 10(4) viral genomes per milliliter of serum. Direct sequencing of the amplified products revealed a major population of DNA molecules with a deletion of nucleotide 31 of the HBs-gene, which up to now has not been described. This deletion led to a frame-shift and introduced a stop-codon after 21 amino acids of the sHBsAg. We suspect that this deletion, and the resulting HBsAg lacking the major epitopes recognized by specific antibodies, could favor ongoing viral replication, despite the presence of anti-HBs. However, because the reading frame of the polymerase was also severely damaged by this deletion, it is assumed that a minor population of intact genomes was present to help in the formation of virus particles.

[High percentage of isolated anti-HBc-positive persons among prisoners]. / Hoher Prozentsatz isoliert anti-HBc-positiver Personen unter Strafgefangenen.

PURPOSE: Is the result "isolated Anti-HBc" higher among prisoners than in the normal population and can testing for HBV-DNA clarify the results? PATIENTS AND METHODS: In Berlin, 519 prisoners were serologically tested in 1994 for hepatitis-B and -C because of intravenous drug abuse and alcohol disease or signs of hepatitis. Beside virus antigen and antibodies, HBV-DNA was also measured by hybridisation technique or PCR. RESULTS: 50.3% of all individuals showed markers of hepatitis-B and 36.8% of hepatitis-C. 19.2% of persons with hepatitis B markers were positive for anti HBc only, i.e. more than twice as many than in the normal population. 90% of the isolated anti-HBc-positive Persons were also anti-HCV positive, which is nearly double the number of individuals with other patterns of HBV markers. Half of them were tested for HBV-DNA. Whereas the hybridisation technique failed to detect HBV-DNA, 36% of sera were found positive by HBV-PCR. CONCLUSION: This study shows again that the result "anti-HBc alone" is relatively frequent especially among prisoners. This pattern often seems associated with concurrent HCV-infection and in one third of the cases correlated with a chronic hepatitis-B. The result of an isolated anti-HBc should therefore always lead to further testing of anti-HCV and HBV-DNA by PCR.

Latent Lyme neuroborreliosis: presence of Borrelia burgdorferi in the cerebrospinal fluid without concurrent inflammatory signs.

Borrelia burgdorferi, the etiologic agent of Lyme borreliosis, was isolated from the CSF of a patient with elevated serum IgG antibody titers against B burgdorferi and a history of multiple tick bites. The absence of concurrent inflammatory signs of CSF as well as intrathecal antibody production indicates a phase of latent Lyme neuroborreliosis in which no tissue infection or reaction has yet occurred. Bilateral tinnitus was the only clinical symptom in this patient. The persistence of the bilateral tinnitus after antibiotic therapy did not support a causal relationship between this symptom and the borrelial infection.

Rheumatoid arthritis masquerading as polymyalgia rheumatica: report of two cases.

Polymyalgia rheumatica is a syndrome rather than a specific entity. The cases of two elderly patients are reported. These patients presented with typical polymyalgia rheumatica, but later were shown to have rheumatoid arthritis. Rheumatoid arthritis in the elderly may first masquerade as polymyalgia rheumatica.

Silicone lymphadenopathy and synovitis. Complications of silicone elastomer finger joint prostheses.

We report two complications of silicone elastomer finger joint prostheses. In one patient, the prostheses broke, with silicone particles present in synovium ("detritic synovitis"). In another patient, silicone particles were found in an axillary lymph node five years after insertion of prostheses in the ipsilateral hand (prostheses were intact at the time). Microscopically, silicone particles in synovium and lymph node were identical to particles abraded from a new prosthesis.