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W Petry

Publications and source records attributed to W Petry.

At least 19 recordsLinked to original sources
PubMed2002

[Hepatocellular carcinoma: rising incidence of hepatitis C virus-associated cases at a university clinic in Germany].

BACKGROUND AND OBJECTIVE: Hepatocellular carcinoma (HCC) ranks eighth among malignant tumors worldwide. Western countries belong to areas of low HCC prevalence, but incidence of HCC is rising. The aim of the present, retrospective study was to determine changes in the incidence rates and risk factors for HCC in Germany based on the data of a single center. PATIENTS AND METHODS: Epidemiological data of 205 consecutive patients with HCC (163 males, 42 females, mean age 64+/-1 years), admitted to the University clinic Düsseldorf between January 1988 and December 2001, were evaluated. For comparison this time period was divided into two equal intervals (1988 - 1994 and 1995 - 2001). RESULTS: The number of newly diagnosed HCC has more than doubled in the years 1995 - 2001 compared to the years 1988 - 1994. Chronic hepatitis C (HCV), hepatitis B (HBV), and chronic alcohol abuse accounted for almost 80 % of HCC. The number of HCV-associated HCC increased from 31.0 % in the years 1990 - 1995 to 44.6 % (p < 0.04) in the years 1996 - 2001, whereas the proportion of HBV-associated HCC decreased. There were no changes in the Okuda tumor stage, tumor diameter and alpha-fetoprotein levels at the time of HCC diagnosis throughout the years 1988 - 2001. More than 65 % of HCC were non-resectable at the time of HCC diagnosis due to tumor diameter or number of tumor lesions. CONCLUSION: Screening for HCC, possibly rising in its incidence, should be further improved, taking into account that chronic HCV infection is the major risk factor for HCC in Germany.

Adult↗
PubMed2001

Calcium rubidium nitrate: mode-coupling beta scaling without factorization.

The fast dynamics of viscous calcium rubidium nitrate is investigated by depolarized light scattering, neutron scattering, and dielectric loss. Fast beta relaxation evolves as in calcium potassium nitrate. The dynamic susceptibilities can be described by the asymptotic scaling law of mode-coupling theory with a shape parameter lambda=0.79; the temperature dependence of the amplitudes extrapolates to T(c) approximately equal 378 K. However, the frequencies of the minima of the three different spectroscopies never coincide, in conflict with the factorization prediction, indicating that the true asymptotic regime is unreachable.

Journal Article↗
PubMed2001

Combination therapy of active HBsAg vaccination and interferon-alpha in interferon-alpha nonresponders with chronic hepatitis B.

Treatment with interferon-alpha leads to cessation of viral replication in 30-40% of patients with chronic hepatitis B. Preliminary data suggest that therapeutic vaccination in patients with chronic HBV infection may be beneficial. The present trial was conducted to assess the efficacy of combination therapy of interferon-alpha with HBsAg vaccination in patients who previously failed to respond to interferon-alpha alone. Eighteen patients positive for HBsAg and HBeAg were included. Mean ALT was 81+/-23 units/liter and 7 (39%) patients had HBV-DNA levels >2000 pg/ml. Patients received 5 million IU interferon-alpha 2b (Intron A) thrice weekly for six months and recombinant HBsAg (Gen H-B-Vax) at the beginning and 4 and 12 weeks after initiation of interferon therapy. No serious side effects were seen during the trial period. Loss of HBeAg was seen in 39% (7/18), HBV DNA was undetectable in 50% (9/18), and ALT was normal in 56% 10/18) of patients six months after completion of therapy. Simultaneous administration of interferon-a and HBsAg vaccination in patients previously not responding to interferon alone appears to be safe, well-tolerated, and it achieved response rates similar to or even higher than interferon in treatment naive patients. This combination therapy seems to offer a new and promising approach for patients with chronic hepatitis B virus infection.

Adult↗
PubMed2000

[New developments in therapy of chronic hepatitis B. When are nucleoside analogs indicated?].

Nucleoside analogues are promising agents for the treatment of chronic hepatitis B infection (HBV-DNA-positive by hybridization assay). The drug being studied most intensively is Lamivudine (Zeffix) which has recently been approved in Germany. When given orally once daily (100 mg) Lamivudine is well-tolerated and suppresses HBV-DNA to undetectable levels in the majority of patients. Since relapse is frequent when medication is stopped long-term treatment (at least until seroconversion of HBeAg) is warranted. Indications for lamivudine monotherapy are patients with chronic hepatitis B in which interferon (IFN) is contraindicated or patients who did not respond to a previous course of interferon. Further indications are the HBV-DNA-positive cirrhosis prior to liver transplantation (OLT) and the HBV-reinfection after OLT. The main problem of long-term monotherapy with lamivudine is viral resistance. The clinical impact of the resistant mutants is often not clear. Withdrawal or even continuation of the medication may be acceptable approaches. Other nucleoside analogues like Entecavir or Adefovir are currently being tested in clinical studies. Famciclovir was investigated preferably in patients with decompensated liver disease or HBV-reinfection after OLT. Because of conflicting results the drug should only be used under study conditions. In IFN-naive patients with chronic hepatitis B (and compensated liver disease) alpha-interferon is still the first-line therapy. With a standard course of interferon 30-40% of the patients become seronegative for HBeAg as compared with 16-17% when treated with lamivudine for twelve months. Combination of lamivudine and interferon is not more effective than IFN alone. In the future combined antiviral treatment is likely to replace monotherapy.

Adenine↗
PubMed2000

[Antiviral therapy of hepatitis C].

Hepatitis C is one of the world's leading infectious diseases. The interferon-ribavirin combination therapy is the new standard for the treatment of hepatitis C in naive and relapse patients. Virological sustained response rates can be more than doubled by the IFN-ribavirin combination therapy compared to IFN-monotherapy and treatment duration can be reduced to six months in many cases. The IFN-ribavirin combination therapy has a high relative benefit in patients with unfavorable predictive parameters like high viral load, HCV genotype-1 infection and compensated liver cirrhosis. Anemia is the most important side effect of the guanosin analogue ribavirin. There are no official therapeutic recommendations for non-responder patients at present. These patients should be treated within controlled clinical trials. Monotherapy with PEG(pegylated)-interferons and combination therapies with PEG-interferons and ribavirin are the most promising future therapeutic options.

Antiviral Agents↗
PubMed1998

Solvent composition and viscosity effects on the kinetics of CO binding to horse myoglobin.

Ligand binding to myoglobin in aqueous solution involves two kinetic components, one extramolecular and one intramolecular, which have been interpreted in terms of two sequential kinetic barriers. In mixed solvents and sub-zero temperatures, the outer barrier increases and the inner barrier splits into several components, giving rise to fast intramolecular recombination. The nature of these barriers and their relation to structural relaxation are examined using the effect of solvent composition and viscosity on the kinetics of CO binding to horse myoglobin in 60% ethylene glycol/water, 75% and 90% glycerol/water, 80% and 92% sucrose/water solutions. Measurements of the corresponding solvent structural relaxation rates by frequency resolved calorimetry allow us to discriminate between solvent composition and viscosity-related effects. The outer kinetic barrier controlling ligand entry and release depends on the viscosity consistent with Kramers-Stokes law of activated escape in the presence of friction. At high cosolvent concentration, we observe deviations from Stokes law, implying a smaller microviscosity at the protein-solvent interface as compared to the bulk. The inner barrier and its coupling to structural relaxation appears to be independent of viscosity but changes with solvent composition. As a possible explanation, we discuss the role of distal water molecules in the formation of the effective inner barrier. At low temperatures, this barrier has a distributed height, depending only slightly on the nature of the cosolvent and temperature at low cosolvent concentrations. In contrast, myoglobin embedded in a sucrose glass (92% sucrose/water) exhibits a temperature-dependent and bimodal enthalpy distribution. This result demonstrates that the exchange between protonation states of His64, A0 left and right arrow A1, can take place in the glass and at temperatures as low as 80 K.

Animals↗
PubMed1998

Prognosis of chronic hepatitis C: results of a large, prospective cohort study.

The prognosis of chronic hepatitis C virus (HCV) infection is still ill-defined. The present study prospectively evaluated mortality and complications in a large cohort of patients with chronic hepatitis C. The study included 838 anti-HCV and HCV-RNA-positive patients who were followed for 50.2 +/- 26.9 months (mean +/- SD; range, 6-122 months) in a prospective protocol. During follow-up, 62 patients died (31 from liver disease and 31 from other causes), and 12 patients needed liver transplantation. When compared with a matched general population, hepatitis C increased mortality mainly when cirrhosis was present and in patients who were less than 50 years old at study entry. During follow-up, a further 30 patients developed nonlethal complications of cirrhosis. By multivariate regression, survival was decreased by cirrhosis, long disease duration, history of intravenous drug abuse, and excessive alcohol consumption, whereas interferon therapy improved survival. Alanine transaminase (ALT), bilirubin, sex, and genotype had no effect on survival. The risk of hepatocellular carcinoma (HCC) (n = 17) was increased by cirrhosis and to a lesser degree by long disease duration and high bilirubin, whereas interferon therapy, genotype, and other factors had no effect. Chronic hepatitis C is a disease with considerable mortality and morbidity when cirrhosis is present at diagnosis. Patients who acquire the infection early in life have a markedly increased mortality even when cirrhosis is absent at diagnosis. The age at diagnosis therefore should play a major role in therapeutic considerations. The present data also suggest that interferon therapy has a long-term clinical benefit, although it did not reduce the risk of liver cancer.

Adult↗
PubMed1998

Value of liver biopsy prior to interferon therapy for chronic viral hepatitis.

The present study prospectively evaluated the value of liver biopsy in patients with chronic hepatitis B (N=75) and C (N=135) prior to interferon therapy. Biopsy specimens revealed cirrhosis in 26% of patients with hepatitis B and 30% with hepatitis C. Although cirrhosis was not predictable by laboratory values in individual patients mean gamma-GT, alkaline phosphatase, and bilirubin levels were significantly higher in patients with cirrhosis compared to those without. Since cirrhosis significantly impairs the response rate to interferon therapy in hepatitis C but not in hepatitis B, liver biopsy is important for the management of chronic hepatitis C infection. In 88% of patients with serum HBV-DNA, irrespective of the serum HBeAg status, chronic active hepatitis was seen. Similarly, chronic active hepatitis was found in 84% of patients with elevated aminotransferases and hepatitis C antibodies. Thus, chronic active hepatitis was diagnosed in the majority of cases with chronic viral hepatitis, showing that this histopathological diagnosis is of little additional value for the recommendation on interferon treatment in these patients. However, none of the other grading systems of liver biopsy specimens described so far have been evaluated for their ability to predict overall prognosis or response rates to interferon therapy. Therefore, the physician is presently left with the questionable value of a procedure with well-known risks and costs in patients suitable for interferon treatment. Hence, prospective randomized controlled studies to evaluate histopathological grading systems are urgently needed to redefine the necessity of liver biopsy in this routine clinical setting.

Antiviral Agents↗
PubMed1997

Vibrational frequency shifts as a probe of hydrogen bonds: thermal expansion and glass transition of myoglobin in mixed solvents.

The contribution of hydrogen bonds to protein-solvent interactions and their impact on structural flexibility and dynamics of myoglobin are discussed. The shift of vibrational peak frequencies with the temperature of myoglobin in sucrose/water and glycerol/water solutions is used to probe the expansion of the hydrogen bond network. We observe a characteristic change in the temperature slope of the O-H stretching frequency at the glass transition which correlates with the discontinuity of the thermal expansion coefficient. The temperature-difference spectra of the amide bands show the same tendency, indicating that stronger hydrogen bonding in the bulk affects the mainchain solvent interactions in parallel. However, the hydrogen bond strength decreases relative to the bulk solvent with increasing cosolvent concentration near the protein surface, which suggests preferential hydration. Weaker and/or fewer hydrogen bonds are observed at low degrees of hydration. The central O-H stretching frequency of protein hydration water is red-shifted by 40 cm-1 relative to the bulk. The shift increases towards lower temperatures, consistent with contraction and increasing strength of the protein-water bonds. The temperature slope shows a discontinuity near 180 K. The contraction of the network has reached a critical limit which leads to frozen-in structures. This effect may represent the molecular mechanism underlying the dynamic transition observed for the mean square displacements of the protein atoms and the heme iron of myoglobin.

Animals↗
PubMed1997

Water-coupled low-frequency modes of myoglobin and lysozyme observed by inelastic neutron scattering.

Conformational changes of proteins often involve the relative motion of rigid structural domains. Normal mode analysis and molecular dynamics simulations of small globular proteins predict delocalized vibrations with frequencies below 20 cm(-1), which may be overdamped in solution due to solvent friction. In search of these modes, we have studied deuterium-exchanged myoglobin and lysozyme using inelastic neutron scattering in the low-frequency range at full and low hydration to modify the degree of damping. At room temperature, the hydrated samples exhibit a more pronounced quasielastic spectrum due to diffusive motions than the dehydrated samples. The analysis of the corresponding lineshapes suggests that water modifies mainly the amplitude, but not the characteristic time of fast protein motions. At low temperatures, in contrast, the dehydrated samples exhibit larger motional amplitudes than the hydrated ones. The excess scattering, culminating at 16 cm(-1), is suggested to reflect water-coupled librations of polar side chains that are depressed in the hydrated system by strong intermolecular hydrogen bonding. Both myoglobin and lysozyme exhibit ultra-low-frequency modes below 10 cm(-1) in the dry state, possibly related to the breathing modes predicted by harmonic analysis.

Animals↗
PubMed1997

[Hepatocellular carcinoma in Germany. Epidemiology, etiology, clinical aspects and prognosis in 100 consecutive patients of a university clinic].

Chronic hepatitis C and B are the main causes of hepatocellular carcinoma (HCC) worldwide. Little is known about the etiology of HCC in Germany which is regarded as a low-prevalence area for viral hepatitis C (HCV) and B (HBV). To assess the etiologic factors of HCC in Germany we have retrospectively analyzed the records of 100 consecutive patients with hepatocellular carcinoma in our clinic. HCC-patients with documented status on HCV/HBV-infection and daily alcohol intake (n = 55) had HCV antibodies in 53%, HBs-Ag in 20%, isolated chronic alcohol abuse in 11% and genetic hemochromatosis in 2%. In 13% of the HCC-patients no risk factor could be identified. Coinfections with HCV and HBV were not observed. Liver cirrhosis was present in 90% of the HCC-patients. In histologically confirmed HCC (n = 71) serum alpha-fetoprotein level was normal (< 8.5 ng/ml) in 20%, moderately elevated (8.5-300 ng/ml) in 48% and considerably elevated (> 300 ng/ml) in 32% of the patients. Only 31% of all patients presented with small single lesions (< or = 5 cm) without evidence for extrahepatic metastases or portal vein thrombosis. Only 30% of the HCC-patients could be treated with a curative intention (28 hepatic resections, one orthotopic liver transplantation). Patients who underwent resection had cumulative 6-month, 1-year, 2-year and 3-year survival rates of 83.8%, 65.9%, 54.3% and 24.8% respectively. Median survival time after resection was 24.8 months compared with 5.8 months in symptomatically treated patients with unresectable HCC (n = 39). Patients with hepatitis C-associated HCC were significantly older than patients with hepatitis B-associated HCC (mean values: 63.2 vs. 54.2 years). Frequency of cirrhosis, tumor stage, alpha-fetoprotein level and prognosis did not differ between groups. In conclusion hepatocellular carcinoma was predominantly associated with chronic HCV-infection. Most patients presented with normal or moderately elevated serum AFP-levels. Prognosis was poor even after hepatic resection.

Adolescent↗