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P Pohjanpelto

Publications and source records attributed to P Pohjanpelto.

At least 19 recordsLinked to original sources
PubMed2001

Factors predicting interferon treatment response in patients with chronic hepatitis c: late viral clearance does not preclude a sustained response.

OBJECTIVES: Because of the suboptimal efficacy, cost, and adverse effects of interferon in chronic hepatitis C (HCV), predictors have been sought to detect patients with a good treatment response. Also, markers for determining a poor response early in the course of therapy, such as the lack of early viral clearance, have been proposed. METHODS: Ninety-seven patients with chronic hepatitis C were enrolled to receive leukocyte alpha-interferon according to a stepped-care management protocol. The final virological treatment response was evaluated in 74 patients after a 6-month post-treatment follow-up. The relationship between pretreatment and during-treatment variables and the long-term response was assessed. RESULTS: Non-1 viral genotype, higher pretreatment ALT levels, and lower gamma-glutamyl transferase (GGT)/ALT ratios and GGT as well as younger age were significantly associated with a sustained response; a trend was also detected for lower serum ferritin levels. Normalization of ALT by 3 months was also a significant predictor of a long-term response. Of the 27 patients carrying the HCV genotype 3a, seven (26%) were still HCV RNA positive at 6 months. Of these patients, however, five (19%) still achieved a sustained virological response after treatment for up to 12 months. CONCLUSIONS: In contrast to some previous reports, our results suggest that a late viral clearance after 6 months of interferon monotherapy may not preclude a favorable long-term response after a 12-month treatment, especially in patients carrying a non-1 HCV genotype. A low pretreatment GGT/ALT ratio is a predictor of a good treatment response.

Adolescent↗
PubMed2000

Leukocyte interferon-alpha in the treatment of chronic hepatitis C in Finland.

BACKGROUND: To evaluate the efficacy of leukocyte interferon in previously untreated patients with chronic hepatitis C, 97 patients were enrolled in a prospective study in Finland with a stepped-care management protocol. METHODS: The treatment was initiated with 3 million units of interferon-alpha subcutaneously three times a week. At 3 months, if the serum alanine aminotransferase was still abnormal, the dose was doubled. If serum hepatitis C virus (HCV) RNA had turned negative at 6 months, the treatment was stopped; if it was still positive, treatment was continued for up to 12 months. All patients were followed up after treatment for 6 months. Altogether, 74 patients completed the treatment and follow-up periods. RESULTS: Of all the originally enrolled patients 36% (35 of 97) achieved sustained virologic response, defined as HCV RNA negativity 6 months after the end of treatment. The commonest HCV genotype among these patients was 3a, and as many as 52% of such patients achieved sustained virologic response. Thirty-two per cent of the patients had HCV genotype 1a, 1b, or a mixture of these; a sustained response was achieved in only 6% of such patients but in 50% of patients with a non-1 genotype. Adverse effects caused treatment cessation for 10% of the patients and IFN dose reduction for 20%. CONCLUSIONS: Monotherapy with human leukocyte interferon resulted in sustained virologic response in 36% of patients with chronic hepatitis C. In those infected with a HCV genotype other than 1, the sustained virologic response rate was 50%.

Adult↗
PubMed1996

Phosphorylation of Okazaki-like DNA fragments in mammalian cells and role of polyamines in the processing of this DNA.

In mammalian cells DNA synthesis is more complicated than in prokaryotes and less well understood. Here we incubated intact mammalian cells (polyamine auxotrophic Chinese hamster ovary cells and primary human fibroblasts) with [32P]orthophosphate and found that, besides high molecular weight DNA, a species of low molecular weight DNA, approximately 450 bp in size, became efficiently labeled. The short DNA was labeled first, and in pulse-chase experiments the labeling was transient. The isolated small DNA fragments (RNase A-treated) were phosphorylated by T4 polynucleotide kinase specific for polynucleotides with 5'-OH ends. A polynucleotide kinase phosphorylating these DNA pieces was also detected in nuclear extracts of the cells. Treatment with alkaline phosphatase removed most of the 32P label incorporated into the small DNA in vivo. Labeling with deoxyribonucleosides did not reveal these fragments. We hypothesize that the low molecular weight DNA represents Okazaki fragments and that the mammalian DNA replication machinery includes a polynucleotide kinase phosphorylating the 5'-termini of Okazaki fragments. This would imply a novel step in DNA synthesis. We also show that depriving cells of polyamines reversibly blocks synthesis of high molecular weight DNA and leads to accumulation of the short DNA pieces, suggesting a role for polyamines in joining the Okazaki fragments.

Alkaline Phosphatase↗
PubMed1996

Hepatitis C genotypes in Finland determined by RFLP.

Genotyping of hepatitis C virus (HCV) is important because of its clinical and epidemiological implications. We report here the distribution of HCV genotypes in various patient groups in Finland using a rapid and reliable HCV typing method based on restriction fragment length polymorphism (RFLP) of the amplified DNA from the 5' non-coding region of the genome. The reaction product from the primary, diagnostic PCR (nested, one tube system) was used in genotyping. From 264 Finnish sera we identified HCV genotypes 1a (14%), 1b (24%), 2b (20%). 3a (41%) and 1a + 1b (1%). Only one patient with genotype 2a was identified. From four Egyptian blood donors, types 1b and 4 were found. Genotype 3a was more often associated with i.v. drug abuse and younger age profile (less than 30 years).

Adult↗
PubMed1994

Flow cytometric analysis of the cell cycle in polyamine-depleted cells.

Polyamines are found in all cells but their function is not fully understood. We have studied the effect of polyamines on the passage of cells through the cell cycle using a polyamine auxotrophic mutant, CHO-P22, which has no detectable ornithine decarboxylase activity. The ability of these cells to grow without serum allows efficient polyamine depletion. A flow cytometric analysis of DNA content and bromodeoxyuridine labeling showed that without added polyamines the cells accumulated in S-phase, the rate of DNA synthesis was retarded, and the entry into mitosis was blocked. Addition of polyamines to cultures deprived of polyamines induced cells in all phases of the cell cycle to reinitiate cycling. Earlier studies have shown that cells with damaged DNA are blocked from entering into mitosis but caffeine can partly overcome this block and induce premature chromosome condensation. Polyamine-depleted CHO-P22 cells responded to caffeine in the same way as cells with damaged DNA. These results show that polyamine depletion in CHO-P22 cells primarily affects DNA synthesis. The finding that polyamine-starved cells continuously take up bromodeoxyuridine without a corresponding increase in the amount of DNA is compatible with extensive repair of erroneous and/or damaged DNA. Polyamine auxotrophic Chinese hamster ovary (CHO) cells might be useful in studies on the regulation of mitosis in mammalian cells.

Animals↗
PubMed1992

A rapid and quantitative solution hybridization method for detection of HBV DNA in serum.

A sensitive and convenient solution hybridization technique was adapted for the semiquantitative detection of hepatitis B virus DNA in serum. The assay utilizes 35S-isotope as label and biotin-avidin interaction for collection of the hybrids onto microtitre plate wells. Results are obtained as numerical values, which allow quantification. 10(6) molecules of HBV DNA/ml serum could be detected by a 3-h hybridization followed by a 2-h collection reaction. By analyzing 500 microliters of serum, 30 (88%) of 34 patient sera positive for HBeAg were also positive for HBV DNA and 17 HBsAg-positive sera, 16 of which were anti-HBe-positive, were DNA-negative. The amount of HBV DNA varied from 5 x 10(6) to 3 x 10(9) molecules/ml. The solution hybridization method which was developed allows fast and accurate quantification of HBV DNA in serum providing an estimate of the virus titre.

DNA, Viral↗
PubMed1992

Risk factors connected with hepatitis C infections in Finland.

Risk factors of 160 hepatitis C virus antibody (anti-HCV) positive patients, found in our serological routine, were analyzed. 89% of the patients had been exposed to blood (64% had a history of i.v. drug abuse, 24% had used whole blood or blood products, 0.6% had a profession connected with blood exposure). 8.1% of the patients had lived or travelled in Southern countries, notably in Africa and in the Eastern Mediterranean, 0.6% had an anti-HCV positive sex partner. 2.5% of the patients had no known risk factors.

Adult↗
PubMed1991

Low prevalence of hepatitis C antibodies in chronic liver disease in Finland.

High prevalence of hepatitis C antibodies (anti-HCV) have been found in the Middle- and Southern European countries in connection with chronic liver diseases. In a study of Finnish chronic liver disease patients no anti-HCV antibodies were found in 22 autoimmune chronic active hepatitis, in 5 chronic persistent hepatitis and in 38 alcoholic liver disease patients. 2/30 primary biliary cirrhosis patients were anti-HCV positive. As a comparison 3/9 patients with acute community acquired non-A non-B hepatitis and 28/48 i.v. drug addicts had anti-HCV antibodies. The results indicate that HCV infections in Finnish chronic hepatitis patients are rare.

Adult↗
PubMed1991

Characteristics and outcome of acute infection with hepatitis B virus in children with cancer.

After an outbreak of hepatitis B virus (HBV) infection in a unit of pediatric oncology, the clinical outcome and HBV markers were followed in 1 child with chronic and 10 children with acute HBV infection for 12 months. Four children had acute hepatitis with jaundice whereas 7 of the infections were subclinical. Ten children had antecedent malignancies and 1 had aplastic anemia. Four patients died of causes unrelated to the hepatitis after periods of 2, 4, 8 and 10 months. All 3 children who were not immunosuppressed at the time of contracting the HBV infection quickly turned negative for hepatitis B surface antigen (HBsAg), whereas only 2 of 8 patients who were immunosuppressed by chemotherapy eventually became HBsAg-negative. The latter 8 patients were also hepatitis B e antigen (HBeAg)-positive. Two of them quickly cleared HBeAg, but 6 remained HBeAg-positive throughout the follow-up. In 6 of 9 patients HBsAg was also detected in saliva. These results suggest that children who are receiving anticancer chemotherapy have an increased risk of remaining HBeAg-positive and secreting HBsAg and possibly HBV in their saliva, which makes them particularly infective.

Acute Disease↗
PubMed1990

Deprivation of a single amino acid induces protein synthesis-dependent increases in c-jun, c-myc, and ornithine decarboxylase mRNAs in Chinese hamster ovary cells.

Genes of higher eucaryotic cells are considered to show only a limited response to nutritional stress. Here we show, however, that omission of a single essential amino acid from the medium caused a marked rise in the mRNA levels of c-myc, c-jun, junB and c-fos oncogenes and ornithine decarboxylase (ODC) in CHO cells. There was no general accumulation of mRNAs in amino acid-starved cells, since the gamma-actin, beta-tubulin, protein kinase C, RNA polymerase II, and glyceraldehyde-3-phosphate dehydrogenase mRNAs and the total poly(A)+ mRNA were not increased. The levels of c-myc, ODC, and c-jun mRNAs were elevated more by amino acid starvation than by inhibition of protein synthesis with cycloheximide, which is known to increase the levels of these mRNAs. Importantly, however, cycloheximide present during amino acid starvation reduced the rise in the levels of the mRNAs down to the level obtained with cycloheximide alone. This implies that protein synthesis is required for the accumulation of c-myc, ODC, and c-jun mRNAs in amino acid-deprived cells. The junB and c-fos mRNAs, instead, were increased to the same extent or less by amino acid starvation than by cycloheximide treatment. The accumulation of the c-myc mRNA in amino acid-starved cells was due to both stabilization of the mRNA and increase of its transcription. The rise in the c-jun mRNA level seemed to be caused merely by stabilization of the mRNA. Further, despite the inhibition of general protein synthesis, amino acid starvation led to an increase in the synthesis of c-myc polypeptide. The results suggest that mammalian cells have a specific mechanism for registering shortages of amino acids in order to make adjustments compatible with cellular growth.

Animals↗
PubMed1988

Polyamine depletion of cells reduces the infectivity of herpes simplex virus but not the infectivity of Sindbis virus.

The effect of polyamines on the viral growth was examined using cell strains that could be effectively depleted of polyamines. In order to avoid the polyamines present in serum we used a polyamine auxotrophic Chinese hamster ovary cell line P22 growing in serum-free medium and Vero cells growing in low serum medium. The final yield of an enveloped RNA virus, Sindbis, in P22 cells was not decreased by depletion of cellular polyamines although the onset of the viral replication was delayed. In contrast the final yield of an enveloped DNA virus, Herpes simplex virus (HSV), was considerably reduced in Vero cells, depleted of polyamines by alpha-difluoromethylornithine, an inhibitor of polyamine synthesis. However, the number of HSV particles detected by electronmicroscopy was not decreased. Southern blot analysis of HSV-DNA from the polyamine depleted and the control cells showed changes in the relative abundance of the DNA fragments suggesting that impairment in DNA synthesis may have caused the decreased infectivity of HSV.

Animals↗
PubMed1987

Alterations in amounts and covalent modifications of low-molecular-weight chromosomal proteins in Chinese hamster ovary cells during polyamine depletion.

The effect of polyamine depletion on phosphorylation and ADP-ribosylation of low-Mr chromosomal proteins was studied in intact, mutant Chinese hamster ovary cells (CHO-P22) devoid of ornithine decarboxylase activity. When starved of polyamines for 6 days, severe polyamine deficiency develops and the cells gradually stop growing. The rate of DNA synthesis was retarded to 16% of the control value and to 29% in density-inhibited cells. The synthesis of high-mobility-group (HMG) proteins was decreased by 65% in polyamine-depleted cells and by 40% in density-inhibited cells. The synthesis of core histones was decreased by 40% both in polyamine-depleted and density-inhibited cells. In polyamine-depleted cells the molar ratio of the higher-Mr HMG proteins (HMG 1 + 2) to the lower-Mr HMG proteins (HMG 14 + P) was about one-half of that found in cells grown in the presence of putrescine or in density-inhibited cells. In contrast to HMG proteins, no major differences were found in the content of core histones in these cell populations. In the perchloric acid-soluble fraction of nuclear proteins, 32P was incorporated mainly into histone H1, HMG P and a protein migrating more slowly than HMG 1 (protein P1). Specific changes in the 32P-labeling and migration of a number of protein bands, including histone H1, was observed in polyamine-depleted cells as compared to cells grown in the presence of putrescine or to density-inhibited cells. ADP-ribosylation experiments using [3H]adenosine showed a different pattern of label distribution; the higher-Mr HMG proteins from polyamine-depleted cells contained about one-half the amount of label found in the proteins from control cells. The lower-Mr HMG proteins and histone H1 were the preferentially labeled proteins in polyamine-depleted cells. Labeling of core histones with [32P]orthophosphate or [3H]adenosine did not differ markedly in the two cell populations. The results obtained using intact polyamine auxotrophic cells indicated that polyamine depletion is connected with more severe alterations in amounts and covalent modifications (phosphorylation and ADP-ribosylation) of HMG chromosomal proteins and histone H1 than core histones.

Adenosine Diphosphate Ribose↗
PubMed1986

Control of ornithine decarboxylase in Chinese hamster ovary cells by polyamines. Translational inhibition of synthesis and acceleration of degradation of the enzyme by putrescine, spermidine, and spermine.

We have recently isolated, without using any inhibitors, a mutant of Chinese hamster ovary cell line which greatly overproduces ornithine decarboxylase in serum-free culture. Addition of polyamines (putrescine, spermidine, or spermine, 10 microM) or ornithine (1 mM), the precursor of polyamines, to the culture medium of these cells caused a rapid and extensive decay of ornithine decarboxylase activity. At the same time the activity of S-adenosylmethionine decarboxylase showed a less pronounced decrease. Notably, the polyamine concentrations used were optimal for growth of the cells and caused no perturbation of general protein synthesis. Spermidine and spermine appeared to be the principal regulatory amines for both enzymes, but also putrescine, if accumulated at high levels in the cells, was capable of suppressing ornithine decarboxylase activity. The amount of ornithine decarboxylase protein (as measured by radioimmunoassay) declined somewhat more slowly than the enzyme activity, but no more than 10% of the loss of activity could be ascribed to post-translational modifications or inhibitor interaction. Some evidence for inactivation through ornithine decarboxylase-antizyme complex formation was obtained. Gel electrophoretic determinations of the [35S]methionine-labeled ornithine decarboxylase revealed a rapid reduction in the synthesis and acceleration in the degradation of the enzyme after polyamine additions. No decrease in the amounts of the two ornithine decarboxylase-mRNA species, hybridizable to a specific cDNA, was detected, suggesting that polyamines depressed ornithine decarboxylase synthesis by selectively inhibiting translation of the message.

Adenosylmethionine Decarboxylase↗
PubMed1986

Phosphorylation of a low Mr high mobility group protein in Chinese hamster ovary cells.

Phosphorylation of high mobility group (HMG) chromatin proteins was studied both in intact Chinese hamster ovary cells (strain CHO-P22) and in vitro conditions using isolated HMG proteins from the same cells and purified protein kinases. Prominent phosphorylation of serine in a low Mr HMG protein designated as HMG P was observed in unsynchronized cells. Of the three protein kinases tested, only nuclear type II protein kinase phosphorylated HMG P in vitro. The phosphorylated amino acid was phosphoserine. Cyclic nucleotide dependent protein kinases did not phosphorylate HMG P but phosphorylated HMG 14 with a preference for cGMP-dependent protein kinase. 32P-labeling of HMG 17 was not observed in intact cells or in vitro.

Amino Acid Sequence↗
PubMed1986

Influence of exfoliation syndrome on prognosis in ocular hypertension greater than or equal to 25 mm. A long-term follow-up.

Data on 144 patients who in 1969-1973 were found to have ocular hypertension greater than or equal to 25 mmHg without glaucomatous damage were collected retrospectively. Intraocular pressure-lowering treatment was prescribed with few exceptions. Thirteen out of 37 patients (35%) with exfoliation syndrome developed glaucomatous damage during the follow-up periods ranging from 5 to 14 years (mean 9.4 years). The corresponding result for patients without exfoliation syndrome was 20 out of 111 subjects (18%, mean follow-up 11.7 years, range 5-15 years). Low average intraocular pressure during the follow-up seemed to prevent the eyes from developing glaucomatous damage. This was especially evident for eyes with the exfoliation syndrome. The long-term effect of medical therapy on the pressure level of hypertensive eyes was often negligible.

Aged↗