Biomedical subjects

A Ropponen

Publications and source records attributed to A Ropponen.

5 recordsLinked to original sources

PubMed2005

Effects of oral and transdermal estradiol administration on levels of sex hormone-binding globulin in postmenopausal women with and without a history of intrahepatic cholestasis of pregnancy.

SHBG, the most important transport protein for sex steroids, is produced in the liver under the control of estrogen action. In a randomized, double-blind, prospective crossover study we compared basal levels of serum SHBG and their responses to increasing doses of oral and transdermal estradiol (E2), followed by E2 plus oral progestin (medroxyprogesterone acetate [MPA]), in 40 postmenopausal women with or without a history of intrahepatic cholestasis of pregnancy (ICP), which could affect the synthesis of SHBG. Serum samples collected at baseline, on the last day of each E2 period, and on the last day of the E2 plus MPA combination were assayed for SHBG and E2. Basal levels of SHBG showed no difference between the study groups. Oral but not transdermal E2 increased SHBG concentrations by 67-171% in the control group, but the response was smaller (42-121%) in the ICP group. Addition of MPA decreased SHBG levels by 14-18% in both groups during both treatments. In conclusion, a history of ICP is associated with blunted responses of SHBG to oral estrogen.

Administration, Cutaneous↗

PubMed2005

CD45RA and RO isoforms have distinct effects on cytokine- and B-cell-receptor-mediated signalling in human B cells.

The common leucocyte antigen, CD45, is widely expressed on the surface of lymphocytes. In T and B cells, CD45 has an important role in the early events of receptor signalling. However, the role of various CD45 isoforms in B-cell receptor (BCR)- and cytokine-induced signalling and proliferation is still unclear. In the present study, we establish two follicular lymphoma cell lines expressing either CD45RA (HF28RA) or CD45R0 (HF28R0) isoforms. It was observed that the two isoforms had distinct effects on BCR- or cytokine-induced cellular proliferation. BCR stimulation significantly increased the proliferation of HF28R0 cells, in contrast to a decreased proliferation of HF28RA cells. Moreover, proliferation of HF28R0 cells significantly increased after the addition of interleukin-2 (IL-2), IL-4, IL-6, IL-10, IL-12, IL-13, IL-15, interferon-gamma and tumour necrosis factor-alpha cytokines, whereas most of these cytokines significantly inhibited the proliferation of HF28RA cells. In addition, the cell lines had their individual cytokine mRNA expression profiles after BCR stimulation. We also analysed the effect of CD45 isoforms on intracellular signalling after BCR stimulation. It was found out that the kinetics of ERK1/2 MAP kinase phosphorylation was clearly faster in HF28R0 than in HF28RA cells. The phosphorylation of other analysed MAP kinases or PTKs was very similar in the cell lines.

B-Lymphocytes↗

PubMed2004

Levels of serum C-reactive protein during oral and transdermal estradiol in postmenopausal women with and without a history of intrahepatic cholestasis of pregnancy.

Liver dysfunction may affect the production and release of C-reactive protein (CRP). We designed a double-blind prospective crossover study involving 40 postmenopausal women with or without a history of intrahepatic cholestasis of pregnancy (ICP), where we compared the basal levels of CRP and their responses to increasing doses of oral and transdermal estradiol (E2), followed by addition of oral medroxyprogesterone acetate (MPA). Serum samples collected at baseline, on the last day of each E2 period, and on the last day of the E2 + MPA combination were assayed for CRP, estrogens, and liver enzymes. There was no difference in basal CRP between the study groups. Both regimens (oral and transdermal E2) were accompanied by significant rises in estrone and E2 concentrations; the former were 16 times higher during the oral than during the transdermal regimen. Oral E2 elevated CRP dose dependently, and this response was unaffected by a history of ICP or the use of MPA. The activities of liver transaminases varied but were in normal ranges during E2 use, in women with and without a history of ICP. In conclusion, the synthesis of CRP is not affected by a history of ICP. It is readily and dose dependently stimulated by oral but not by transdermal E2 in as soon as 2 wk.

Administration, Cutaneous↗

PubMed2003

Genetic evidence of heterogeneity in intrahepatic cholestasis of pregnancy.

BACKGROUND AND AIMS: The aim of this study was to investigate the genetic aetiology of intrahepatic cholestasis of pregnancy (ICP) and the impact of known cholestasis genes (BSEP, FIC1, and MDR3) on the development of this disease. PATIENTS AND METHODS: Sixty nine Finnish ICP patients were prospectively interviewed for a family history of ICP, and clinical features were compared in patients with familial ICP (patients with a positive family history, n=11) and sporadic patients (patients with no known family history of ICP, n=58). For molecular genetic analysis, 16 individuals from two independently ascertained Finnish ICP families were genotyped for the flanking markers for BSEP, FIC1, and MDR3. RESULTS: The pedigree structures in 16% (11/69) of patients suggested dominant inheritance. Patients with familial ICP had higher serum aminotransferase levels and a higher recurrence risk (92% v 40%). Both segregation of haplotypes and multipoint linkage analysis excluded BSEP, FIC1, and MDR3 genes in the studied pedigrees. Additionally, the MDR3 gene, previously shown to harbour mutations in ICP patients, was negative for mutations when sequenced in four affected individuals from the two families. CONCLUSIONS: These results support the hypothesis that the aetiology of ICP is heterogeneous and that ICP is due to a genetic predisposition in a proportion of patients. The results of molecular genetic analysis further suggest that the previously identified three cholestasis genes are not likely to be implicated in these Finnish ICP families with dominant inheritance.

ATP Binding Cassette Transporter, Subfamily B↗

PubMed2001

Repeatability of lifetime exercise reporting.

The purpose of the study was to determine the reliability of lifetime exercise data obtained through a structured interview. Interviews were conducted in 1992-1993 and repeated in 1997 in 150 monozygotic male twins, aged 35-69 years, from the population-based Finnish Twin Cohort. Exercise mode, frequency, duration, intensity and period of participation were solicited for each regularly performed exercise from 12 years of age to the present. Questions related to the most common exercise mode reported in the initial interview were repeated in all subjects and the entire exercise interview was repeated in a subgroup of 38 subjects. The repeatability was highest for exercise years and mean hours/ week by mode for the most commonly performed exercise (Mean ICC=0.63-0.90), and for the sum of all lifetime exercises reported (Mean ICC = 0.69-0.73). The lowest repeatability was found for exercise intensity (Mean Kappa = 0.33-0.48). Similarly poor reliability was found for whether or not exercise was performed at a competitive level (Mean Kappa = 0.25-0.63). Overall, the structured interview of lifetime exercise was most repeatable for years of exercise and mean hours/week. Thus, these exposure variables should be considered in retrospective studies of exercise effects.

Adult↗