Alisporivir with peginterferon/ribavirin in patients with chronic hepatitis C genotype 1 infection who failed to respond to or relapsed after prior interferon-based therapy: FUNDAMENTAL, a Phase II trial.

Alisporivir (ALV) is an oral, investigational host-targeting agent, with pangenotypic activity against hepatitis C virus (HCV). This randomized, double-blind, placebo-controlled, Phase II study explored the efficacy and safety of ALV with peginterferon-α2a/ribavirin (PR) in patients with chronic HCV genotype 1 infection in whom prior PR had failed (43% relapsers, 34% null responders and 23% partial responders). Four-hundred-and-fifty-nine patients were randomized (1:1:1:1) to ALV 600 mg once daily (QD), ALV 800 mg QD, ALV 400 twice daily (BID) or placebo plus PR for 48 weeks. When the global ALV trial programme was put on clinical hold, all patients in this study had received ≥31 weeks of randomized treatment; patients completed 48 weeks on PR alone. All ALV groups demonstrated superior rates of complete early virologic response (cEVR; primary endpoint) vs PR alone (P ≤ 0.0131), with highest cEVR rate seen with ALV 400 mg BID (74% vs 36% with PR alone; P < 0.0001). Respective SVR12 rates (key secondary endpoint) were 65% vs 26% in prior relapsers, 63% vs 5% in partial responders and 68% vs 3% in null responders. In patients who received >40 weeks of randomized treatment, the SVR12 rate was 89% for ALV 400 mg BID vs 30% for PR alone (P = 0.0053). Rates of viral breakthrough and relapse were lowest with ALV 400 mg BID. One case of pancreatitis (fully recovered) occurred with ALV/PR. Common AEs were headache, fatigue, anaemia, neutropenia and nausea. Hypertension was infrequent, but more common with ALV. ALV merits further investigation in interferon-free regimens in combination with direct-acting antiviral agents.

Decline in pulmonary function during chronic hepatitis C virus therapy with modified interferon alfa and ribavirin.

Rare interstitial lung disease cases have been reported with albinterferon alfa-2b (albIFN) and pegylated interferon alfa-2a (Peg-IFNα-2a) in chronic hepatitis C virus (HCV) patients. Systematic pulmonary function evaluation was conducted in a study of albIFN q4wk vs Peg-IFNα-2a qwk in patients with chronic HCV genotypes 2/3. Three hundred and ninety-one patients were randomly assigned 4:4:4:3 to one of four, open-label, 24-week treatment groups including oral ribavirin 800 mg/d: albIFN 900/1200/1500 µg q4wk or Peg-IFNα-2a 180 µg qwk. Standardized spirometry and diffusing capacity of the lung for carbon monoxide (DLCO) were recorded at baseline, weeks 12 and 24, and 6 months posttreatment, and chest X-rays (CXRs) at baseline and week 24. Baseline spirometry and DLCO were abnormal in 35 (13%) and 98 (26%) patients, respectively. Baseline interstitial CXR findings were rare (4 [1%]). During the study, clinically relevant DLCO declines (≥15%) were observed in 173 patients (48%), and were more frequent with Peg-IFNα-2a and albIFN 1500 µg; 24 weeks posttreatment, 57 patients (18%) still had significantly decreased DLCO, with a pattern for greater rates with albIFN vs Peg-IFNα-2a. One patient developed new interstitial CXR abnormalities, but there were no clinically relevant interstitial lung disease cases. The risk of persistent posttreatment DLCO decrease was not related to smoking, alcohol, HCV genotype, sustained virologic response, or baseline viral load or spirometry. Clinically relevant DLCO declines occurred frequently in chronic HCV patients receiving IFNα/ribavirin therapy and commonly persisted for ≥6 months posttherapy. The underlying mechanism and clinical implications for long-term pulmonary function impairment warrant further research.

Randomized trial of albinterferon alfa-2b every 4 weeks for chronic hepatitis C virus genotype 2/3.

Albinterferon alfa-2b (albIFN) is a fusion protein of recombinant human albumin/recombinant interferon (IFN)-α-2b, with ∼200-h half-life. Safety/efficacy of albIFN q4wk was evaluated in 391 treatment-naive patients with chronic hepatitis C virus (HCV) genotype 2/3. Patients were randomized 3:4:4:4 to one of four open-label treatment groups: pegylated IFN (Peg-IFN)-α-2a 180 µg qwk or albIFN 900, 1200 or 1500 µg q4wk, plus oral ribavirin 800 mg/day, for 24 weeks. Primary efficacy endpoint was sustained virologic response (SVR; HCV RNA <20 IU/mL 24 weeks post-treatment). SVR rates were as follows: 85%, 76%, 76% and 78% with Peg-IFNα-2a and albIFN 900, 1200 and 1500 µg, respectively (P = NS); corresponding rapid virologic response rates (HCV RNA <43 IU/mL at week 4) were as follows: 78%, 49% (P < 0.001), 60% (P = 0.01) and 71%. SVR rates were not influenced by interleukin 28B genotype, although rapid virologic response rates were greater with interleukin 28B CC (P = NS). Serious adverse event rates were as follows: 4%, 11%, 3% and 3% with Peg-IFNα-2a and albIFN 900, 1200 and 1500 µg, respectively. No increase in serious/severe respiratory events was noted with albIFN. Fewer absolute neutrophil count reductions <750/mm(3) occurred with albIFN (P = 0.03), leading to fewer IFN dose reductions. Haemoglobin reductions <10 g/dL were less frequent with albIFN 900 and 1200 µg vs 1500 µg and Peg-IFNα-2a (P = 0.02), leading to fewer ribavirin dose reductions. albIFN administered q4wk produced fewer haematologic reductions than Peg-IFNα-2a, but had numerically lower SVR rates (P = NS) in patients with chronic HCV genotype 2/3.

Immunosuppressive therapy and hepatitis C virus infection: the clinical course of liver disease.

In a retrospective long-term follow-up study the clinical course of liver disease was examined in renal allograft recipients with hepatitis C virus (HCV) infection and negative hepatitis B surface antigen under immunosuppressive therapy. We compared 42 anti-HCV antibody (anti-HCV) positive patients (study group) to 213 anti-HCV negative patients (control group). All patients received immunosuppressive therapy. Measurements were made of the following: aminotransferases, bilirubin, albumin, gammaglobulins, ascites, spleen diameter, HCV RNA, and anti-HCV antibody. We found all but four anti-HCV positive patients to be HCV RNA positive prior to transplantation. There were no differences in overall mortality or mortality secondary to liver disease or sepsis. Normal liver enzymes were found in 13 (31%) anti-HCV positive and in 137 (64%) anti-HCV negative patients during the whole mean observation period of 65 months (range 10-215). Aminotransferase activity decreased in anti-HCV positive and negative patients during the observation period. Liver function with regard to synthesis and excretion was normal in anti-HCV negative and anti-HCV positive patients. No signs of portal hypertension were observed in the anti-HCV positive group. Neither the different immunosuppressive regimens nor the antirejection therapy led to differences between anti-HCV positive and negative groups with respect to liver function and did not alter the clinical course. We conclude that HCV infection in patients under immunosuppressive therapy causes only a mild liver disease, as determined by clinicochemical and clinical parameters, and that mortality rate is not increased.

Complete remission of Crohn's disease after high-dose cyclophosphamide and autologous stem cell transplantation.

In a 36-year-old male with ileocolic Crohn's disease (CD) no long-lasting remission was obtained by treatment with corticosteroids, mesalazine, azathioprine and antibiotics. Surgical interventions due to relapsing fistulae and abscesses resulted in the removal of >1.5 m of small bowel and left only 40 cm of large bowel. In July 2000, a new fistula and abscess developed. The combination of corticosteroids, mesalazine, ciprofloxacin, metronidazol, azathioprine, formula diet and anti-TNF-alpha antibody largely reduced clinical activity, and resection of fistula and abscess were successful. Despite clinical remission, histology showed activity in the small bowel and the colon. In March 2001, stem cell mobilization chemotherapy with cyclophosphamide was performed. It induced an endoscopic remission for 9 months, which was maintained on azathioprine and corticosteroids. After relapse, in March 2002, high-dose chemotherapy with cyclophosphamide and reinfusion of T-cell-depleted autologous peripheral CD34+ blood stem cells were performed. This led to a complete clinical, endoscopical and histological remission for 9 months without any treatment. Thereafter, endoscopy showed initial aphthous lesions with minimal histological signs of inflammation. The patient is asymptomatic, but low-dose prednisolone and methotrexate are prophylactically given. Immunoablative chemotherapy followed by autologous peripheral blood stem cell transplantation may be a beneficial therapeutic option in complicated refractory CD.

Prefrontal cortical hypometabolism during low-dose interferon alpha treatment.

OBJECTIVE: To evaluate prospectively interferon alpha (IFN-alpha) associated effects on cerebral glucose metabolism and its correlation to neuropsychiatric symptoms during low-dose IFN-alpha-treatment. METHODS: Eleven patients treated with low-dose IFN-alpha for chronic hepatitis C were prospectively evaluated by neuropsychiatric tests and cerebral [18F]deoxyglucose positron emission tomography (FDG-PET) before and in the 12th week of treatment. PET images were spatially normalized, corrected for variance in global activity and pixel-based t-statistics were calculated for each set of PET scans using SPM96 software. Pixel-cluster with P<0.001 for hypo- or hypermetabolism were displayed in parametric images. Covariance analysis with neuropsychiatric tests was calculated for each cluster. RESULTS: In week 12 of IFN-alpha treatment, significant hypometabolism with a decrease of local activity ranging from 8 to 12% was found in all patients bilaterally in the prefrontal cortex (BA 9), which correlated in a covariate analysis with changes in depression score as measured by Beck's Depression Inventory. Additionally, hypermetabolism with a maximum increase in local activity of 6-8% was seen in all patients in putamina as well as the left occipital region (BA 18). Before IFN-alpha treatment, only 1/11 patient showed depressive symptomatology. After 3 months of treatment, 6/11 patients were classified as having mild to moderate depressive symptoms (P<0.1; Wilcoxon test). CONCLUSIONS: Low-dose IFN-alpha therapy is associated with significant prefrontal hypometabolism. This hypometabolism covaried with depression score, but was even found in clinically non-depressed patients. These findings may reflect a possible predisposing factor for IFN-alpha associated neuropsychiatric syndromes and might contribute to a pathophysiological model of affective disorders, as endogenous IFN-alpha levels are elevated in a subset of psychotic patients during acute disease.

Amplification of unknown DNA sequences by sequence-independent nested polymerase chain reaction using a standardized adaptor without specific primers.

A new procedure for sequence-independent PCR amplification of DNA fragments is described. DNA from pUC18 plasmid was used as a test DNA. It was digested with a frequently cutting restriction enzyme (Sau3A), generating sticky ends. The DNA was ligated to a synthetic, non-phosphorylated adaptor and subsequently amplified in a nested PCR using two oligonucleotides with sequences derived from the adaptor. As little as 1 fg of pUC18 DNA could be detected by this procedure. The product was analyzed on a gel and hybridized with a pUC18-specific probe. The sequence-independent nested PCR was repeated with different amounts of pUC18 DNA in the presence of an excess of non-specific DNA. In these experiments, pUC18 DNA fragments were amplified in a concentration-dependent manner. After hybridization with a digoxigenin dUTP-labelled pUC18 DNA probe, 1 fg of pUC18 DNA could still be detected. This method allows rapid screening of blood for low titred and mutated viruses in which primer binding sites are not conserved.

Quasispecies analysis in hepatitis C virus infection by fluorescent single strand conformation polymorphism.

Hepatitis C virus (HCV) results frequently in chronic hepatitis and its sequelae liver cirrhosis and hepatocellular carcinoma. Interferon-alpha is at present the most effective treatment, resulting in a sustained response in about 20-25% of patients. HCV genotype, titer and quasispecies determine the success of treatment. In this study, fluorescent single strand conformation polymorphism (f-SSCP) was evaluated for the analysis of HCV quasispecies. Two sera from a chronically HCV-infected patient, obtained 6 years apart, were examined. The hypervariable region I (HVRI) of the HCV genome was amplified by reverse transcription and PCR. The PCR products were cloned and sequenced or fluorescein-labeled and subjected to f-SSCP. Both methods demonstrated a single HCV species in the early serum and multiple quasispecies in the late serum. Single clones of the heterogeneous virus population were used to optimize conditions for f-SSCP. The most important factors were the gel temperature and virus titer. At the optimal running temperature one base exchange in 218 bases was detectable. Repeat extractions and amplifications gave identical results. Dilution of the serum containing multiple quasispecies resulted in a 'loss' of species. Provided the running temperature is optimal and virus titer is sufficient, f-SSCP is shown to be fast and reliable for HCV quasispecies analysis.

The glutamine analog acivicin as antipyrimidine. Studies on the interrelationship between pyrimidine and urea synthesis in liver.

The inhibition of cytosolic carbamoyl-phosphate synthetase II by acivicin was used to study the role of the cytosolic carbamoyl phosphate pool as the exclusive substrate source for de novo pyrimidine synthesis in rat hepatocytes. De novo pyrimidine synthesis was stimulated: 1. by uridine triphosphate deficiency (incubation with D-galactosamine) leading to a stimulation of cytosolic carbamoyl phosphate synthesis, and 2. by accumulation and efflux of mitochondrial carbamoyl phosphate (incubation with ammonium ions and L-norvaline). The stimulated orotate formation from cytosolic carbamoyl phosphate in UTP depleted cells was completely blocked by acivicin. It was not influenced by an inhibition of mitochondrial carbamoyl phosphate synthesis mediated by 4-pentenoate, since mitochondrial carbamoyl phosphate did not participate in cytosolic pyrimidine synthesis even in the presence of ammonium ion concentrations maintaining physiological rates of urea synthesis. An excess of ammonium ions led to an artificial accumulation and efflux of mitochondrial carbamoyl phosphate, which could be avoided by 4-pentenoate. The non-regulated stimulation of pyrimidine synthesis from surplus mitochondrial carbamoyl phosphate was not inhibited by acivicin. Utilization of mitochondrial carbamoyl phosphate for de novo pyrimidine synthesis presumably does not occur under physiological conditions because mitochondrial CP efflux depends on the accumulation of this metabolite in the mitochondria under experimental or pathological circumstances. Acivicin inhibition of CPS II thus cannot be bypassed by mitochondrial CP. It is suitable as inhibitor of the physiological de novo pyrimidine synthesis.

Occurrence and management of hepatitis B virus reactivation following kidney transplantation.

A 28-year-old woman was kidney transplanted. She had an inapparent hepatitis B virus (HBV) infection 2 years previously. At the time of transplantation she was hepatitis B surface antigen (HBsAg) negative, anti-HBs, anti-HBc, anti-HBe and anti-HCV antibody positive and her transaminase activities were within the normal range. The donor of the kidney allograft was HBV negative. Twelve weeks after transplantation a life-threatening liver failure occurred with a rapid rise of alanine aminotransferase (ALT) to 1427 U/l and a decrease of the prothrombin time to 25% of normal value. Anti-HBs had become negative, anti-HBc and anti-HBe titers had decreased. HBsAg became positive, associated with a HBV DNA of 3 x 10(8) genome equivalents/ml. Azathioprine and prednisone were withdrawn and foscarnet therapy was started. This therapy led to a decrease of ALT activity associated with an elimination of HBsAg and HBV DNA. Eight months after transplantation liver function tests were within the normal range. Graft rejection did not occur despite low or intermittent cessation of immunosuppressive therapy.

Re-treatment of chronic hepatitis C patients after relapse: efficacy of peginterferon-alpha-2a (40 kDa) and ribavirin.

We conducted a randomized multinational study to determine whether 48 weeks of re-treatment with peginterferon-alpha-2a (40 kDa) plus ribavirin would induce a sustained virological response (SVR) in relapsed chronic hepatitis C patients. Patients who had previously relapsed during 24 weeks of untreated follow-up, after having achieved an end-of-treatment virological response with 24 weeks of peginterferon-alpha-2a (40 kDa)/ribavirin combination therapy, within a phase III trial, were studied. Although the recommended dosage was the same as that used at the end of the initial trial, adjustments were permitted. Data on serious adverse events, or adverse events that resulted in dose reductions or discontinuations, were collected. Following re-treatment, the overall SVR rate in the 64 patients was 55%. The SVR rates in patients infected with hepatitis C virus (HCV) genotype 1 and non-1 genotypes were 51% and 63%, respectively. Early (week 12) virological responses were seen in 39 patients (61%) and were predictive of an SVR. Re-treatment was well tolerated. The most frequent adverse events recorded were fatigue (5%) and abdominal pain (3%). Dosages of peginterferon-alpha-2a (40 kDa) and/or ribavirin were modified because of adverse events in 3% and 13% of patients, and because of laboratory abnormalities in 23% and 5% of patients, respectively. Thus, a 48-week course of peginterferon-alpha-2a (40 kDa) plus ribavirin induces an SVR in 55% of patients who relapsed during follow-up after 24 weeks of combination therapy. Physicians should not hesitate to offer re-treatment to patients who relapse after an initial, 24-week course of combination therapy, or who have prematurely stopped treatment because, for example, of laboratory abnormalities.

Peginterferon {alpha}-2b and ribavirin therapy in chronic hepatitis C genotype 4: impact of treatment duration and viral kinetics on sustained virological response.

BACKGROUND: The response rates and duration of peginterferon alpha (PEG-IFN-alpha) and ribavirin combination therapy in chronic hepatitis C genotype 4, the prevalent genotype in the Middle East and Africa, are poorly documented. AIMS: To compare the efficacy and safety of 24, 36, or 48 weeks of PEG-IFN-alpha-2b and ribavirin therapy in chronic hepatitis C genotype 4. METHODS: In this prospective, randomised, double blind study, 287 patients with chronic hepatitis C genotype 4 were randomly assigned to PEG-IFN-alpha-2b (1.5 mug/kg) once weekly plus daily ribavirin (1000-1200 mg) for 24 weeks (group A, n = 95), 36 weeks (group B, n = 96), or 48 weeks (group C, n = 96) and followed for 48 weeks after completion of treatment. Early viral kinetics and histopathological evaluation of pre- and post treatment liver biopsies were performed. The primary end point was viral clearance 48 weeks after completion of treatment. RESULTS: Sustained virological response was achieved in 29%, 66%, and 69% of patients treated with PEG-IFN-alpha-2b and ribavirin for 24, 36, and 48 weeks, respectively, by intention to treat analysis. No statistically significant difference in sustained virological response rates was detected between 36 and 48 weeks of therapy (p = 0.3). Subjects with sustained virological response showed greater antiviral efficacy (epsilon) and rapid viral load decline from baseline to treatment week 4 compared with non-responders and improvement in liver histology. The incidence of adverse events was higher in the group treated for 48 weeks. CONCLUSION: PEG-IFN-alpha-2b and ribavirin for 36 or 48 weeks was more effective in the treatment of chronic hepatitis C genotype 4 than treatment for 24 weeks. Thirty six week therapy was well tolerated and produced sustained virological and histological response rates similar to the 48 week regimen.

[Hepatitis C--standard therapy]. / Hepatitis C--Standard-Therapie.

Infection with the hepatitis C virus leads to chronic hepatitis in the majority of patients. Diagnosis is based on the presence of anti-HCV antibodies and confirmed by positive HCV RNA. The natural course of the disease is slow. Cirrhosis is found in a minority of patients two decades post infection. Nevertheless, cirrhosis is much more frequently observed than in patients with hepatitis B infection. Treatment of choice is interferon-alpha. Today combination with ribavirin is recommended for most patients. In combination therapy the sustained response rate six months after stop of treatment is about 40% in naive patients with respect to virus elimination. In patients treated with high doses of interferon-a for one year the sustained response rate is comparable. The response rate is higher in patients with HCV infections of non-1 genotype and in patients with lower virus titers, e.g. less than 2 Mill. genome equivalents per ml. Interferon-a treatment also leads to an improvement of liver histology. Necro-inflammatory scores are reduced. It has also an antifibrogenic effect. Progression of fibrosis is reduced. The antiproliferative effect of interferon-a leads a lower rate of hepatocellular carcinomas, which has been demonstrated in several retrospective studies. In patients with Child A cirrhosis the time till decompensation is delayed. Because of the slow progression, the relatively low response rate and the adverse events of interferon-a and ribavirin treatment should be instituted on an individual base depending on host factors such as age, co-morbidity and stage of liver disease.

[Conservative therapy of ulcerative colitis and Crohn disease]. / Die konservative Therapie von Colitis ulcerosa und Morbus Crohn.

Basis treatment of severe ulcerative colitis and Crohn's disease comprises the systemic administration of corticosteroids. If the conditions are less severe, treatment with oral sulfasalazine or 5-aminosalicylic acid (5-ASA) can be attempted. Distal ulcerative colitis may respond to topical corticosteroids of enemas with sulfasalazine or 5-ASA. In long-term treatment with high-dose corticosteroids, azathioprine and 6-mercaptopurine may be employed to reduce the corticosteroid requirement. There ist no known generally applicable diet for the treatment or prophylaxis of these conditions.

Isolation, characterization and biological significance of hepatitis B virus mutants from serum of a patient with immunologically negative HBV infection.

BACKGROUND/AIM: A low-titered hepatitis B virus infection without immunological markers was identified in a prospective study in the serum of a kidney transplant recipient by PCR. The aim of this study was to analyze HBV genomes and their biological significance. METHODS: The genome was amplified in two overlapping fragments A and B. Sequencing of 22 clones of the A- and 12 clones of the B-fragment revealed a heterogeneous virus population. A consensus and a mutant sequence were computed, representing the complete sequence of the virus population. The two sequences were compared with 41 published genomes of the different HBV geno- and serotypes. RESULTS: Ninety-five point mutations and two deletions were identified. Two mutations were observed in all clones and 17 other mutations in three or more clones. The deletions were found in ten and seven of 22 clones. They were located in the C-gene and led to stop codons yielding truncated e- and/or core proteins. In vitro transfection of DNA constructs containing these deletions demonstrated a stop of HBV replication and of HBeAg expression. Cotransfection experiments demonstrated a dominant negative effect of the mutants containing the deletions. In addition, we describe new variants of naturally occurring HBsAg mutants that may cause HBV infection less detectable by standard HBsAg measurement assays. They were characterized by two point mutations which were observed in 9 of 12 and 13 of 22 clones of the S-gene. They significantly reduced the HBsAg expression in in vitro transfection experiments. CONCLUSION: We found a patient with low-titered HBV infection, with mutations of the 'a' epitope of the Santigen as well as with mutations leading to truncated core proteins which may cause a dominant negative effect.

De novo pyrimidine biosynthesis in isolated rat hepatocytes. Quantitative aspects of the regulation by UTP.

Quantitative aspects of de novo pyrimidine biosynthesis in rat hepatocytes were monitored. A reduction of intracellular UTP contents by different concentrations of D-galactosamine led to a dose-dependent increase of 14CO2 incorporation into the sum of all acid-soluble uracil nucleotides. In controls the rate of de novo synthesis which was calculated from the incorporation rate of 14CO2 into the sum of all acid-soluble uracil nucleotides was 0.014 mumol X h-1 X g-1 compared to 0.056 mumol X h-1 X g-1 wet weight of liver in situations of a maximally stimulated de novo synthesis. Incubation of hepatocytes with uridine led to a dose-dependent reduction of 14CO2 incorporation to less than 25% of the amount incorporated in the controls. Alterations of the CTP content had no influence on the 14CO2 incorporation. In the presence of high D-galactosamine concentrations the increase of the total amount of acid-soluble uracil nucleotides exceeded the rate of the de novo synthesis derived from the incorporation of 14CO2 into the sum of the acid-soluble uracil nucleotide pool. It was also greater than the increase of the total amount of intra- and extracellular orotate after acidic hydrolysis--even in the presence of 6-azauridine, which stimulated de novo pyrimidine biosynthesis by itself.

[Autoantibodies against islet cell antigens and type 1 diabetes after treatment with interferon-alpha]. / Autoantikörper gegen Inselzellantigene und Diabetes mellitus Typ 1 unter Interferon alpha-Kombinationstherapie.

BACKGROUND AND OBJECTIVE: The aim of this study was to study the appearance of autoantibodies against islet cells and the development of type 1 diabetes in patients with chronic hepatitis C during interferon treatment. PATIENTS AND METHODS: 74 patients (24 women, 50 men, mean age: 46 years) with HCV infection were treated with interferon, ribavirin and amantadin versus placebo, after they had failed to previous interferon therapy in a prospective, randomised trial. At the end of treatment period anti-islet cell autoantibodies (anti-GAD, anti IA-2), anti-insulin antibodies, TSH, anti-thyroid autoantibodies (TPO, thyreoglobulin, TSH-receptor antibodies) were measured. RESULTS: In two patients, GAD autoantibodies were found, but both patients were negative for IA-2 and insulin antibodies. One of the patients developed type 1 diabetes five months after start of treatment. In this patient, the anti-GAD titer was initial 0 U/ml (normal: < 1.2). The titer raised to 52,2 U/ml after the interferon monotherapy. During the second interferon treatment (in combination) the titer raised from initial 41,1 U/ml to 59,6 U/ml. The anti-GAD titer of the second patient was 0 U/ml before treatment and raised to 1,7 U/ml. This patient did not develop a type 1 diabetes. CONCLUSION: Type 1 diabetes is a rare but serious complication of interferon therapy. Repetitive treatment seems to facilitate this complication. Screening for islet antibodies before a second therapy could be useful.

Hepatic carbamoyl phosphate metabolism. Role of cytosolic and mitochondrial carbamoyl phosphate in de novo pyrimidine synthesis.

The interrelationship between the two carbamoyl phosphate pools in intact hepatocytes and intact liver was studied with respect to de novo pyrimidine synthesis by use of selective inhibitors of the mitochondrial and the cytosolic carbamoyl-phosphate synthetase. Inhibition of mitochondrial carbamoyl phosphate synthesis by 4-pentenoate was without effect on galactosamine-stimulated pyrimidine synthesis. Conditions favouring mitochondrial carbamoyl phosphate accumulation, like excess ammonium ions or L-norvaline, led to an increase in pyrimidine synthesis bypassing the feedback inhibition of cytosolic carbamoyl-phosphate synthetase by UTP. A stimulation of pyrimidine synthesis was not observed when the carbamoyl phosphate accumulation was due to aspartate deficiency in the presence of aminooxyacetate. The full response of pyrimidine synthesis to excess ammonium ions was restored, even in the presence of aminooxyacetate, when aspartate was substituted. This is explained by an inhibition of aspartate carbamoyltransferase flux [in view of the Km (aspartate = 0.7 mmol/l) of this enzyme] resulting from a 90% decrease in aspartate tissue levels. Acivicin, the inhibitor of cytosolic carbamoyl-phosphate synthetase, completely abolished the galactosamine-induced stimulation of pyrimidine synthesis, but was without effect on the stimulation of pyrimidine synthesis by ammonium ions and L-norvaline. It is concluded that experimental changes in mitochondrial carbamoyl phosphate content exert effects on de novo pyrimidine synthesis; however, it is considered unlikely that relevant amounts of mitochondrial carbamoyl phosphate are used for pyrimidine synthesis under physiological conditions. In addition the data point to a potential regulatory role of aspartate in hepatic pyrimidine synthesis.