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Biomedical subjects

T Berg

Publications and source records attributed to T Berg.

At least 127 records · Page 7Linked to original sources
PubMed1997

Distribution of hepatitis C virus genotypes in German patients with chronic hepatitis C: correlation with clinical and virological parameters.

BACKGROUND/AIMS: The hepatitis C virus genotypes have been shown to be differently distributed between distinct geographical areas and to be associated with different clinical presentations. In the present study we investigated the distribution of HCV genotypes in 379 German patients with chronic hepatitis C in relation to age, sex, route of infection, liver histology and viremia. METHODS: Typing of HCV was done using restriction fragment length polymorphism analysis as well as a DNA enzyme immunoassay. HCV RNA concentrations were determined by quantitative polymerase chain reaction. Liver biopsies were performed in 187 patients and the histological activity was graded by the Knodell score. RESULTS: Seventy percent were infected with genotype 1 (20% subtype 1a, 80% subtype 1b), 4% with genotype 2 and 26% with genotype 3 (all subtype 3a). Genotype 3a and 1a infection was significantly associated with intravenous drug abuse. In contrast, genotype 1 predominated in patients with post-transfusion hepatitis and infection of unknown origin. A changing relative prevalence of HCV genotypes in relation to age was also observed. Patients with genotype 3 infection showed significantly lower HCV RNA levels and a lower mean histological activity score as compared to patients with genotype 1 and genotype 2. However, using multivariate analysis, only age and mode of transmission but not histological activitiy score were shown to be independent variables. CONCLUSIONS: Our study confirms previous reports from other countries that HCV variants can be classified into a relatively small number of discrete genotypes, and that the subtype 1b clearly predominates. However, we found evidence that there is a changing relative prevalence of HCV genotypes in relation to age, and that the mode of transmission is reflected in the predominance of certain genotypes.

Adolescent↗
PubMed1997

Use of mosses (Hylocomium splendens and Pleurozium schreberi) as biomonitors of heavy metal deposition: from relative to absolute deposition values.

Concentrations of 48 elements in the ground growing mosses Hylocomium splendens and Pleurozium schreberi have been compared with wet deposition data for the same elements at 13 Norwegian sites. Significant positive correlations were found for V, Fe, Co, As, Y, Mo, Cd, Sb, Ce, Sm, Er, Tl and Pb in Hylocomium splendens, and for Mg, V, Fe, Co, As, Se, Y, Mo, Cd, Sb, Tl and Pb in Pleurozium schreberi. Regression equations for transforming moss concentration data to absolute deposition rates have been calculated for those of the above elements which are of interest from a pollution point of view. The concentration levels of Li, Be, Mg, Ca, Zn, Ge, As, Se, Sr, Y, Zr, Sn, Cs, Ba, La, Ce, Pr, Nd, Sm, Ho, Yb, Hf, Ta and U were similar in the two moss species. Hylocomium splendens had highest concentrations of Cr, Fe, Co, Ni, Cu, Ga, Nb, Mo, Sb, Eu, Gd, Tb, Dy, Er, Tm, Lu, W, Tl, Pb and Th, whereas V, Mn, Rb and Cd were highest in Pleurozium schreberi. No variations were observed in the concentrations of the studied elements during the sampling season.

Journal Article↗
PubMed1997

Signalling pathways in bradykinin- and nitric oxide-induced hypotension in the normotensive rat; role of K+-channels.

1. Bradykinin and nitric oxide (NO) are potent hypotensive agents. In the present study, the role of K+-channels in the signalling pathways responsible for their hypotensive action was investigated in normotensive, anaesthetized rats. The rats were treated with ion-channel inhibitors before administration of bradykinin (2.8, 5.6, 28 and 56 nmol kg(-1), i.v.) followed in some of the protocols by nitroprusside (1.1, 3.5, 7, 14, and 28 nmol kg(-1), i.v.). 2. No attenuation of the hypotensive response to bradykinin was detected for inhibitors of the Na-K-Cl-cotransporter (30 micromol kg(-1) furosemide), the ATP-sensitive K+-channel (40 micromol kg(-1) glibenclamide), high conductance Ca2+-activated K+-channel (180 micromol kg(-1) tetraethylammonium, 54 micromol kg(-1) tetrabutylammonium, 35 nmol kg(-1) iberiotoxin, 35 nmol kg(-1) charybdotoxin) or the low conductance Ca2+-activated K+-channel (74 nmol kg(-1) apamin). 3. However, the voltage-sensitive K+-channel (I(A)) inhibitor 4-aminopyridine (4.05-40.5 micromol kg(-1)) induced a concentration-dependent (P<0.0001) attenuation of the hypotensive response (P<0.0001). Bradykinin had no effect on heart rate in anaesthetized rats and this observation was not altered by pretreatment with 4-aminopyridine. 4. 4-Aminopyridine (53 micromol kg(-1)) also significantly attenuated the hypotensive response to nitroprusside (P<0.0003) without altering the heart rate concentration-response curve. Of the two Ca2+-activated K+-channel inhibitors tested on nitroprusside-induced hypotension, tetrabutylammonium induced a slight attenuation (P<0.0101), whereas iberiotoxin had no effect. 5. We therefore concluded that, although the acute hypotensive response to bradykinin in the normotensive rat is not mediated through nitric oxide synthesis, the hypotensive response to both agents was mediated through opening of voltage-sensitive K+-channels (I(A)), resulting in a decrease in peripheral vascular resistance.

Animals↗
PubMed1997

alpha-Mannosidosis: functional cloning of the lysosomal alpha-mannosidase cDNA and identification of a mutation in two affected siblings.

a-Mannosidosis (MIM 248500) is an autosomal recessive lysosomal storage disorder resulting from deficient activity of lysosomal alpha-mannosidase (LAMAN) (EC 3.2.1.24). The disease is characterized by massive intracellular accumulation of mannose-rich oligosaccharides with resulting mental retardation, hearing loss, immune deficiency and skeletal changes. We report here the purification and characterization of human placenta LAMAN. The enzyme is synthesized as a single-chain precursor which is processed into three glycopeptides of 70, 42 and 15 kDa. The 70 kDa peptide is further partially proteolysed into three more peptides that are joined by disulfide bridges. The laman cDNA sequence was assembled from overlapping fragments obtained by PCR on human fibroblast and human lung cDNA. The deduced amino acid sequence contains a putative signal peptide of 48 amino acids followed by a polypeptide sequence of 962 amino acids. Northern blot analyses revealed a single transcript of approximately 3.5 kb present in all tissues examined but at varying levels. Two affected siblings of Palestinian origin were homozygous for a mutation that causes a His-->Leu replacement at a position which is conserved among class 2 alpha-mannosidases from several species.

Amino Acid Sequence↗
PubMed1997

Diamond-Blackfan anaemia in a girl with a de novo balanced reciprocal X;19 translocation.

A 7 year old girl is described with congenital hypoplastic anaemia (Diamond-Blackfan anaemia, DBA) and an apparently balanced reciprocal translocation, 46,XX,t(X;19)(p21;q13). The girl has associated features including short stature, unilateral kidney hypoplasia, and a branchial cyst. Fluorescent in situ hybridisation (FISH) studies with 19q specific cosmids showed that the chromosome 19 breakpoint is located between the RYR1 and the XRCC11 loci spanning a physical region of 5 Mb. There is no family history of DBA and the parents and two healthy sibs have normal karyotypes. This is the first report of a balanced translocation associated with DBA and we suggest that the distinct phenotype has resulted from a de novo disruption of a functional gene. DBA can be inherited as an autosomal trait and our observation may indicate a candidate gene for the disorder in the 19q13 region.

Blood Transfusion↗
PubMed1997

Amplification of kinin-induced hypotension by nitric oxide synthesis in spontaneously hypertensive rats.

We studied the role of nitric oxide and adrenergic activation in the blood pressure (BP) response to exogenous bradykinin in spontaneously hypertensive rats (SHR) compared with normotensive Wistar-Kyoto rats (WKY). Rats were pretreated with the nitric oxide synthase inhibitor N omega-nitro-L-arginine methyl ester (L-NAME), the alpha-adrenergic receptor antagonist phentolamine together with L-NAME, or phentolamine alone. Sham-injected rats were used as controls. All rats subsequently received bradykinin (3, 6, and 30 micrograms/kg i.v.). Bradykinin induced a concentration-dependent fall in BP in both WKY and SHR (P < .0005). The change in BP was greater in SHR than WKY (P < .0001). BP before bradykinin administration was elevated in the L-NAME group in both strains. In WKY, L-NAME or L-NAME plus phentolamine did not alter the delta BP concentration-response curve to bradykinin (P = NS), whereas in SHR, the delta BP concentration-response curve was attenuated (P < .0048). The attenuation was observed for the two lower bradykinin doses (P < .0005) but not the highest. In SHR, phentolamine alone reduced BP before bradykinin to the same level as in WKY controls, and its delta BP concentration-response curve was not different from that of the normotensive controls or L-NAME and L-NAME plus phentolamine SHR groups. No difference was observed in the duration of the hypotensive response in SHR compared with WKY. The present results confirm that in normotensive rats, the hypotensive effect of bradykinin was mediated by an unknown mechanism other than through the release of nitric oxide. However, in SHR, this mechanism was amplified by additional activation of nitric oxide synthesis. This bradykinin-activated nitric oxide production may be a pressure-induced mechanism to counteract the hypertensive condition.

Adrenergic alpha-Antagonists↗
PubMed1996

GB virus C infection in patients with chronic hepatitis B and C before and after liver transplantation.

Recently, a novel virus, tentatively designated GB virus (GBV-C) was identified in patients with hepatitis. The frequency of this novel virus infection was therefore investigated in 58 patients with chronic hepatitis B virus (HBV) infection and in 74 patients with chronic hepatitis C virus (HCV) infection who had received orthotopic liver transplantation (OLT) because of decompensated liver cirrhosis. Before OLT, GBV-C sequences were found by reverse transcription nested polymerase chain reaction with primers derived from the helicase-like region in six (10%) of the HBV- and in six (8%) of the HCV-infected patients. Specificity of the polymerase chain reaction products was confirmed in eight of them by direct sequencing. Pretransplant GBV-6 viremia was associated with posttransplant viremia in 75% of patients. The comparison of GBV-C nucleotide and amino acid sequences within the helicase-like region revealed that pre- and posttransplant sequences differed only in 0-7 nucleotide exchanges, and with the exception of one, all of them were silent mutations. After OLT, 29% of the HBV- infected and 12% of the HCV-infected patients became GBV-C positive,indicating a high rate of "de novo" GBV-C infection. By correlating the GBV-C status with the frequency of the occurrence of graft hepatitis in both groups of patients, it became evident that posttransplant GBV-C viremia did not increase the risk for this clinical condition. However, we found a significantly higher percentage of hepatocellular carcinoma in patients with pre-OLT GBV-C/HCV coinfection compared with patients with HCV infection alone (5/6 vs. 16/68;P<0.01).

Adult↗
PubMed1996

Liver cell uptake and degradation of soluble immunoglobulin G immune complexes in vivo and in vitro in rats.

Immune complexes were formed between dinitrophenylated human serum albumin (DNP-HSA) and polyclonal rabbit immunoglobulin G (IgG) anti-DNP antibodies at antibody excess. The antigen was labelled with isotope (125I-tyramine-cellobiose) or fluorochrome, (6-[fluorescein-5-(and-6)-carboxamido] hexanoic-acid, succinimidyl ester). The radiolabelled antigen, native or antibody complexed, was given intravenously to rats. Radioactivity was measured in various organs at 1 hour following injection. The liver was the main site for removal of the antigen as well as of the immune complexes. Within the liver, immune complexes were mainly associated with nonparenchymal liver cells, the total recovery from Kupffer cells being about 10 times greater than from the liver endothelial cells. The uncomplexed radiolabelled antigen was readily degraded by both cells types. After IgG complexing, the degradation decreased, both in Kupffer cells and in liver endothelial cells. In vitro experiments with isolated liver cells, showed that IgG complexing increased antigen uptake to about the same extent in Kupffer cells and in liver endothelial cells. The degradation of both antigen and immune complexes was less efficient in vitro than in vivo. Immune complex uptake in vitro was shown also by confocal fluorescence microscopy in Kupffer cells and in liver endothelial cells. Also in vitro, only minor uptake was found in the hepatocytes. We conclude that both liver endothelial cells and Kupffer cells are involved in the hepatic handling of soluble IgG immune complexes, but we found no evidence for substantial uptake by hepatocytes.

Animals↗
PubMed1996

Viral dynamics of hepatitis C early after orthotopic liver transplantation: evidence for rapid turnover of serum virions.

The pathogenesis of hepatitis C virus (HCV) infection is likely to be associated with viral replication in vivo, but little is known concerning the dynamics of HCV turnover. We performed serial measurements of serum HCV-RNA levels following orthotopic liver transplantation (OLT) in nine patients with HCV-positive cirrhosis. Serum HCV-RNA levels were determined by quantitative polymerase chain reaction before, immediately after, and for up to 1 month after OLT. There was a rapid decline in HCV-RNA levels from 3.1 +/- 1.3 x 10(5) copies/ mL (mean +/- SEM) preoperatively to 0.15 +/- 0.6 x 10(5) copies/mL on the first and 0.16 +/- 0.6 x 10(5) copies/mL on the second postoperative day (mean viral half-life, 4.0 +/- 0.5 h). Thereafter, HCV-RNA levels increased in all but one patient, and by postoperative day 8 reached 3.6 +/- 1.3 x 10(5) copies/mL, exceeding the preoperative levels irrespective of the use or not of rescue immunosuppressive therapy including steroid bolus administration. In most patients, serum virions continued to increase averaging 11.6 +/- 2.8 x 10(5) copies/mL on the 30th postoperative day. These findings indicate that the half-life of HCV is quite short, and that extrahepatic viral replication contributes little to the total virus pool in serum. Furthermore, the marked HCV replication beginning as early as the third postoperative day strongly suggests that the liver graft is rapidly reinfected by HCV after OLT.

Adult↗
PubMed1996

Famciclovir therapy for recurrent hepatitis B virus infection after liver transplantation.

Between November 1993 and June 1995 18 patients received oral famciclovir (3 x 500 mg) for treatment of hepatitis B virus (HBV) reinfection after liver transplantation. Reinfection was defined as the reoccurrence of HBsAg in the serum. In the first 15 patients, famciclovir therapy was initiated after clinical signs of graft hepatitis, whereas the last 3 patients received treatment immediately after HBV-DNA was detected. Famciclovir was well-tolerated in all patients. HBV-DNA values were decreased to undetectable levels in 8 out of 18 patients. Clinical status improved in 7 patients, whereas 5 patients remained unchanged and 6 patients progressed to deteriorating graft function and death. When famciclovir was initiated early after reinfection, a response rate of approximately 66% was observed. Late onset of therapy in patients with fulminant hepatitis generally failed to provide any clinical benefit.

2-Aminopurine↗
PubMed1996

Hepatitis GBV-C sequences in patients infected with HCV contaminated anti-D immunoglobulin and among i.v. drug users in Germany.

BACKGROUND/AIMS: A novel virus, GB virus-C (GBV-C), with a genome organization similar to those of the Flaviviridae family was identified in sera of patients diagnosed with hepatitis. Up to now little has been known about the prevalence of GBV-C sequences in German hepatitis C virus infected patients. METHODS: We investigated two groups of patients chronically infected with hepatitis C virus: (i) Women infected in 1978/79 with HCV-contaminated anti-D immunoglobulin batches in former Eastern Germany, and (ii) i.v. drug users infected with different HCV subtypes. Nested polymerase chain reaction products amplified with GBV-C specific primer pairs within the helicase region were sequenced directly and compared with the GBV-C sequences reported recently. RESULTS: GBV-C sequences of the putative NS 3 gene region were shown to occur in two randomly selected anti-D immunoglobulin batches of 1978 (GI and GII) and two sera of HCV-infected women drawn in 1979. In patient 3, the HCV-infected erythrocyte donor in 1978, specific GBV-C sequences were also evident in serum drawn in 1990. In the high-risk group of i.v. drug users, 49% were GBV-C RNA positive. Among the 21 GBV-C positive samples, 11 were coinfected with HCV subtype 3a and 10 with subtype 1 b. All isolates showed an overall homology to the GBV-C sequence reported by Simons of 75-81% at the nucleotide level and 94-100% at the amino acid level. CONCLUSION: GBV-C sequences are detectable in the anti-D immunoglobulin batches which caused a hepatitis C virus outbreak in 1979, and a first hint of its transmission to recipients was shown. The detection of GBV-C in patient serum drawn 12 years after the onset of chronic liver disease confirms the persistence of the novel virus described here. In the group of i.v. drug users a high frequency of GBV-C sequences (49%) was shown, and the considerable variability of the nucleotide sequences indicates the existence of different GBV-C genotypes/subtypes.

Adolescent↗
PubMed1996

Responsiveness to interferon alpha treatment in patients with chronic hepatitis C coinfected with hepatitis G virus.

BACKGROUND/AIMS: Patients with chronic hepatitis C are often coinfected with the new identified Flaviviridae-like agent, termed hepatitis G virus (HGV). The aim of the study was to investigate the responsiveness of hepatitis G virus to interferon alpha and to evaluate whether a hepatitis G virus coinfection negatively influences the outcome of treatment in chronic hepatitis C. METHODS: One hundred and fifteen patients with histologically proven chronic hepatitis C were treated with interferon alpha and investigated for the presence of hepatitis G virus coinfection by nested polymerase chain reaction with primers from the helicase region of hepatitis G virus. All patients received at least 3 MU (range 3-6) interferon alpha thrice weekly for at least 6 months (mean 8, range 6-12). Polymerase chain reaction products of seven pre- and post-treatment hepatitis G virus positive patients were directly sequenced for identification of sequence variability during the follow-up. RESULTS: Eighteen (16%) patients were coinfected with hepatitis G virus. Although nine (50%) of these patients became HGV RNA negative during interferon alpha therapy, only three patients (17%) remained HGV RNA negative at the end of follow-up (mean 24 months). The rate of sustained response of chronic hepatitis C was not significantly different between patients with hepatitis C virus infection and HCV/HGV coinfection (19% vs 28%). Severity of liver disease as determined by alanine aminotransferase levels, histology and hepatitis C virus viremia was not significantly different in patients with hepatitis C virus or HCV/HGV coinfection. Sequence analysis of the helicase region revealed that our isolates all belonged to the hepatitis G virus and not to the GBV-C like genotype. No amino acid exchanges during the observation period of up to 48 months were observed, indicating that this region is highly conserved. CONCLUSIONS: The responsiveness of hepatitis G virus to interferon alpha in chronic HCV/HGV coinfected patients is similar to that observed in chronic hepatitis C. Hepatitis G virus coinfection seems not to interfere with the efficacy of interferon alpha treatment in patients with chronic hepatitis C.

Adult↗
PubMed1996

Treatment of pain in pediatric oncology: a Swedish nationwide survey.

Pain treatment is a crucial aspect in the care of children with cancer and there are many studies demonstrating inefficient pain treatment. In this study, questionnaires dealing with pain treatment of children with malignant diseases were sent to all (47) pediatric departments in Sweden. The aims of this nationwide survey were to evaluate the extent and causes of pain, the use of methods for pain evaluation (e.g. analysis of type of pain and monitoring of pain intensity), principles of pain management, side effects of pain treatment and the educational needs of physicians and nurses regarding these issues. The response rate was 100%. Answers from physicians and nurses reveal that pain is a common symptom during different periods of cancer treatment. Pain due to treatment and procedures is a greater problem than pain due to the malignant disease itself. Instruments for the measurement of pain intensity and analysis of the type of pain are still rarely used. Most physicians (63%) follow the analgesic 'ladder' principle recommended by World Health Organization (WHO). According to a majority of physicians and nurses (72%), pain could be treated more effectively than it is presently, and 64% state that they need more time for the management of pain. Both physicians and nurses state that they need additional education in different areas of pain evaluation and pain treatment. Swedish treatment practices for the management of pediatric cancer pain roughly follow the published guidelines, but many improvements are still necessary.

Adolescent↗