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Biomedical subjects

P Koskinen

Publications and source records attributed to P Koskinen.

At least 19 recordsLinked to original sources
PubMed1999

Prevention of cardiac allograft arteriosclerosis by protein tyrosine kinase inhibitor selective for platelet-derived growth factor receptor.

BACKGROUND: Increased immunoreactivity of platelet-derived growth factor (PDGF)-AA, -Ralpha, and -Rbeta in intimal cells correlates with the development of cardiac allograft arteriosclerosis, a condition for which there is little or no current therapy. Therefore, we hypothesized that PDGF may have a rate-limiting role in the development of this disease. METHODS AND RESULTS: The hypothesis was tested in a rat model of heterotopic cardiac and aortic allografts using dark agouti (AG-B4, RT1(a)) donors and Wistar-Furth (AG-B2, RT1(u)) recipients. The recipients received CGP 53716, a selective PDGF-R protein tyrosine kinase inhibitor, 50 mg. kg-1. d-1, or vehicle for 60 days. Cardiac allograft recipients also received background cyclosporin A immunosuppression. Our results demonstrate that CGP 53716 significantly reduced the incidence and intensity of arteriosclerotic lesions in rat cardiac and aortic allograft recipients. When rat coronary smooth muscle cells were stimulated in vitro with PDGF-AA or -BB in the presence of interleukin-1beta or tumor necrosis factor-alpha, CGP 53716 significantly inhibited only AA-ligand-induced but not BB-ligand-induced replication. Concomitantly, in quantitative reverse transcriptase-polymerase chain reaction, interleukin-1beta or tumor necrosis factor-alpha stimulation specifically upregulated the expression of PDGF-Ralpha mRNA but not of other ligand or receptor genes in cultured smooth muscle cells. CONCLUSIONS: We conclude that a PDGF-AA/Ralpha-dependent cycle is induced in the generation of allograft arteriosclerosis that may be inhibited by blocking of signaling downstream of PDGF-R.

Animals↗
PubMed1999

Prediction of pre-eclampsia with maternal mid-trimester total renin, inhibin A, AFP and free beta-hCG levels.

We wanted to study if maternal serum mid-trimester total renin, inhibin A, AFP or free beta-hCG levels predict the development of pre-eclampsia. Maternal serum alpha-fetoprotein (AFP) and human chorion gonadotrophin (beta-hCG) were evaluated in the screening programme for Down syndrome in 4356 patients prospectively. Data on pregnancy outcome were available in 1242 women. Pregnancy-induced hypertension (PIH) developed in 69 women, 282 women with uneventful pregnancy outcome were selected for controls. Serum total renin and inhibin A levels were measured retrospectively in the trisomy screening samples of 69 and 30 patients who later developed PIH, and in 282 and 7 patients, respectively, who had an uneventful pregnancy outcome. No significant differences were found in the levels of maternal mid-trimester serum total renin, inhibin A or free beta-hCG levels between PIH and healthy women. The multiples of the median (MoM) of AFP values were significantly higher in the subgroup of patients who later developed severe pre-eclampsia than in patients with mild pre-eclampsia or gestational hypertension and healthy pregnant women. Maternal mid-trimester serum levels of total renin, inhibin A and free beta-hCG are not predictive for development of PIH. High mid-trimester serum AFP values may help in the prediction of severe pre-eclampsia.

Adult↗
PubMed1999

Obesity regulates bioavailable testosterone levels in women with or without polycystic ovary syndrome.

OBJECTIVE: To evaluate [1] the effects of levels of sex hormone-binding globulin (SHBG), albumin, and total testosterone on the distribution of testosterone between SHBG-bound and non-SHBG-bound fractions; [2] the independent effects of polycystic ovary syndrome (PCOS) and body mass index on serum levels of total testosterone, non-SHBG-bound testosterone, SHBG, and albumin; and [3] the usefulness of levels of total testosterone and non-SHBG-bound testosterone and of the free androgen index in the diagnosis of PCOS. DESIGN: Retrospective clinical study. SETTING: An academic research environment. PATIENT(S): Forty-three women with oligomenorrhea and PCOS. Twenty-five women with regular menstrual cycles and without hirsutism served as controls. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Levels of non-SHBG-bound testosterone, total testosterone, SHBG, and albumin in serum. RESULT(S): Levels of total testosterone and non-SHBG-bound testosterone, and the free androgen index were higher in patients with PCOS than in healthy controls. PCOS did not have an effect on the levels of SHBG or albumin, or on the percentage of non-SHBG-bound testosterone. Levels of SHBG and albumin were inversely related to body mass index. The percentage and concentration of non-SHBG-bound testosterone and the free androgen index were directly related to body mass index. Hirsutism did not have an effect on any outcome measure. CONCLUSION(S): The distribution of total testosterone into SHBG-bound and non-SHBG-bound fractions is associated with body mass index, not with PCOS. The high levels of non-SHBG-bound testosterone and the high free androgen index in patients with PCOS reflect mainly high levels of total testosterone. Thus, the measurement of levels of non-SHBG-bound testosterone and the calculation of the free androgen index provide no further information in the diagnosis of PCOS beyond that provided by the measurement of levels of total testosterone.

Adult↗
PubMed1999

Suppression of GH secretion in pituitary gigantism by continuous subcutaneous octreotide infusion in a pubertal boy.

We describe a 12-y-old boy with excessive growth hormone and prolactin secretion presumably due to diffuse somatotroph hyperplasia. Until mid-puberty, his growth rate was under reasonable control, with high-dose octreotide injections every 8 h combined with a dopamine agonist. As his growth velocity started to increase, the efficacy of continuous s.c. octreotide infusion on GH secretion was tested. Similar total daily doses (600 microg) of octreotide were administered either by incremental s.c. injections at 8 h intervals, or by continuous s.c. infusion, two-thirds of the amount during night-time to control the presumed high nocturnal growth hormone (GH) peaks of the pubertal growth spurt. An overnight GH profile showed inadequate suppression of GH levels by incremental injections, while continuous s.c. infusion efficiently brought down the GH secretion. Another somatostatin analogue, lanreotide as a single depot injection was not effective. A 6-mo trial on the s.c. infusion regimen significantly reduced growth hormone secretion (as judged by IGF-I and IGFBP3 concentrations), and normalized growth velocity overcoming the pubertal growth spurt. It also caused a decrease in the pituitary size in magnetic resonance images. We conclude that the efficacy of octreotide infusion in suppressing GH secretion is superior to incremental injections with the same dose.

Child↗
PubMed1999

Effect of hyperbaric conditions on plasma stress hormone levels and endothelin-1.

To study a generalized stress reaction as well as endothelin-1 concentrations during moderate hyperbaria and hyperbaric oxygen (HBO2), eight professional divers were exposed to air (O2 21%, AIR) and oxygen (O2 100%, HBO2) at 2.5 atm abs for 60 min in separate sessions. Plasma concentrations of epinephrine, norepinephrine, dihydroxyphenylglycol (metabolite of norepinephrine), cortisol, ADH, renin, aldosterone, pro-ANP, and endothelin-1 were analyzed before, during, and 20 min after the treatments. Endothelin-1 increased significantly (6% during HBO2 and 18% during AIR, and 30 and 34% after the treatments, respectively, P = 0.032). There was no statistically significant difference in the changes of mean norepinephrine and dihydroxyphenylglycol levels between the treatments, although both seemed to change slightly during the treatments, but not over the baseline (time effect P = 0.031 and P = 0.011, respectively). Cortisol levels decreased significantly (P = 0.001) during the treatments. No significant changes were found in other analyzed hormones. The authors concluded that a) HBO2, and hyperbaric air at 2.5 atm abs do not induce a generalized hormonal stress reaction, and b) endothelin-1 increases during HBO2 and hyperbaric air at 2.5 atm abs.

Aldosterone↗
PubMed1998

Effect of ethanol drinking, hangover, and exercise on adrenergic activity and heart rate variability in patients with a history of alcohol-induced atrial fibrillation.

To elucidate the mechanism of alcohol-induced atrial fibrillation (AF) we studied the heart rate variability and parameters of the adrenergic system during alcohol intake, hangover, and exercise in 6 men (mean age 43 years) prone to alcohol-induced AF, together with 6 age-matched controls. The ambulatory (15 hour) electrocardiogram was recorded and blood samples were taken for lymphocytic beta adrenoceptor, plasma catecholamine, and cyclic adenosine monophosphate (cAMP) measurements before and after alcohol intake (blood alcohol 1.5 per thousand), during hangover, and after a standardized bicycle exercise test. The beta-adrenoceptor density in lymphocytes was unchanged in the control group after alcohol intake or during hangover. Each of the AF patients had an increase in beta-adrenoceptor density after ethanol drinking (mean increase 29%, p <0.05). The hangover or exercise beta-receptor values did not differ from those in corresponding controls. Plasma adrenaline concentration tended to decrease and noradrenaline to increase after drinking and during hangover in both groups. Plasma cAMP levels were lower in patients after drinking than in controls (p <0.05). The exercise values of the adrenergic parameters were very similar in AF patients whether or not preceded by alcohol. Analysis of ambulatory electrocardiography showed a very low rate of ectopic beats in both AF patients and controls. Analysis of heart rate variability revealed a tendency toward an increase in sympathetic/parasympathetic component ratio (low-frequency/high-frequency ratio) in AF patients, but not in controls, after ethanol drinking. In conclusion, no signs of arrhythmogenic cardiac disease were detected in patients with AF to explain the tendency toward AF. Increases in beta-adrenoceptor density and low-frequency/high-frequency ratio during ethanol intoxication in patients with AF suggest an exaggerated sympathetic reaction.

Adrenergic beta-Agonists↗
PubMed1998

Associations between human aldosterone synthase (CYP11B2) gene polymorphisms and left ventricular size, mass, and function.

BACKGROUND: Aldosterone has direct and indirect effects on the heart, and genetic variations in aldosterone synthesis could therefore influence cardiac structure and function. Such variations might be associated with polymorphisms in the gene encoding aldosterone synthase (CYP11B2), the enzyme catalyzing the last steps of aldosterone biosynthesis. METHODS AND RESULTS: A Finnish population sample of 84 persons (44 women) aged 36 to 37 years was studied by M-mode and Doppler echocardiography to assess left ventricular size, mass, and function. Subjects were genotyped through the use of the polymerase chain reaction for two diallelic polymorphisms in CYP11B2: one in the transcriptional regulatory region (promoter) and the other in the second intron. In multiple regression analyses, the CYP11B2 promoter genotype predicted statistically significant variations in left ventricular end-diastolic diameter (beta=.40, P<.0001), end-systolic diameter (beta=.33, P=.0009), and mass (beta=.17, P=.023). These effects were independent of potentially confounding factors, including sex, body size, blood pressure, physical activity, smoking, and ethanol consumption. Genotype groups also differed in a measure of left ventricular diastolic function, the heart rate-adjusted atrial filling fraction (P=.018). Increased dietary salt, which is known to predict increased left ventricular mass, had this effect only in association with certain CYP11B2 genotypes (P<.001). CONCLUSIONS: Genetic variations in or near the aldosterone synthase (CYP11B2) gene strongly affect left ventricular size and mass in young adults free of clinical heart disease. These polymorphisms may also influence the response of the left ventricle to increases in dietary salt.

Adult↗
PubMed1998

Alcohol, cardiac arrhythmias and sudden death.

Studies in experimental animals have shown varying and apparently opposite effects of alcohol on cardiac rhythm and conduction. Given acutely to non-alcoholic animals, ethanol may even have anti-arrhythmic properties whereas chronic administration clearly increases the animals' susceptibility to cardiac arrhythmias. Chronic heavy alcohol use has been incriminated in the genesis of cardiac arrhythmias in humans. The evidence has come from clinical observations, retrospective case-control studies, controlled studies of consecutive admissions for arrhythmias, and prospective epidemiological investigations. Furthermore, electrophysiological studies have shown that acute alcohol administration facilitates the induction of tachyarrhythmias in selected heavy drinkers. The role of alcohol appears particularly conspicuous in idiopathic atrial fibrillation. Occasionally, ventricular tachyarrhythmias have also been provoked by alcohol intake. Several lines of evidence suggest that heavy drinking increases the risk of sudden cardiac death with fatal arrhythmia as the most likely mechanism. According to epidemiological studies this effect appears most prominent in middle-aged men and is only partly explained by confounding traits such as smoking and social class. The basic arrhythmogenic effects of alcohol are still insufficiently delineated. Subclinical heart muscle injury from chronic heavy use may be instrumental in producing patchy delays in conduction. The hyperadrenergic state of drinking and withdrawal may also contribute, as may electrolyte abnormalities, impaired vagal heart rate control, repolarization abnormalities with prolonged QT intervals and worsening of myocardial ischaemia or sleep apnoea. Most of what we know about alcohol and arrhythmias relates to heavy drinking. The effect of social drinking on clinical arrhythmias in non-alcoholic cardiac patients needs to be addressed further.

Alcohol Drinking↗
PubMed1998

Long-term effects of allogeneic bone marrow transplantation (BMT) on pituitary, gonad, thyroid and adrenal function in adults.

To evaluate the late-effects of allogeneic bone marrow transplantation (BMT) on endocrine function 20 adults (10 females, 10 males) with hematological malignancies were studied after a mean of 3.2 years (range 1.0-10.0) following BMT. The mean age of patients at the time of BMT was 39 years. Dynamic tests of the hypothalamic-pituitary axis included growth hormone releasing hormone (GHRH), gonadotropin releasing hormone (GnRH) and thyrotropin releasing hormone (TRH) stimulations with measurements of serum growth hormone (GH), follicle stimulating hormone (FSH), luteinizing hormone (LH), thyrotropin (TSH) and prolactin (PRL) responses. Adrenal function was assessed with the adrenocorticotropin (ACTH) test. Five patients (25%) had a subnormal GH response to GHRH stimulation, but all had a normal serum insulin-like growth factor I (IGF-I) value. There was an inverse nonlinear relationship between the body mass index (BMI; kg/m2) and GH response but no relation between the GH response and total body irradiation (TBI), intrathecal treatment or occurrence of graft-versus-host disease. In females, serum FSH and LH basal levels and responses to GnRH, in spite of oestrogen substitution therapy in 9/10 patients, indicated ovarian failure and early menopause. Most responses to GnRH were delayed. All males had elevated serum basal FSH levels indicating damage in seminiferous tubulus and infertility. Serum basal LH was elevated only in four males but testosterone values were all within normal limits. However, the mean free androgen index (FAI) was in the low normal range, and two subjects had abnormally low FAI. Serum free thyroxine (fT4) levels were normal in all but one, but an exaggerated TSH response to TRH occurred in seven patients (35%). Four of them had received TBI and one total nodal irradiation suggesting radiation-induced damage to the thyroid gland. In 19 of the 20 patients, adrenal function judged with ACTH test was normal. We conclude that functional impairments of the hypothalamus-pituitary-gonad/thyroid axis are common while disturbances in GH, adrenal and prolactin occur less often in patients after intensive treatment and BMT. Typically, the target organ is more commonly affected than the hypothalamus-pituitary axis. In spite of normal serum testosterone and LH values, serum FAI may reveal androgen deficiency.

Adolescent↗
PubMed1998

The hypothalamus-pituitary-gonad axis and testicular function in male patients after treatment for haematological malignancies.

OBJECTIVE: The effect of aggressive chemotherapy on the hypothalamus-pituitary-gonad axis and on testicular function was assessed in nine male patients who had received chemotherapy only (CT, group I) and in 10 males after allogeneic bone marrow transplantation (BMT, group II). The mean time from CT or BMT to the assessment was 3.7 (range, 1.0-11.7) years. DESIGN: The responses of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were assessed by the gonadotropin-releasing hormone (GnRH) test and, in addition, serum basal values for testosterone and sex hormone binding globulin (SHBG) were measured and the free androgen index (FAI) was calculated. In 13/19 patients the human chorionic gonadotropin (hCG) test was performed. RESULTS: In group I, only one patient had an abnormal basal FSH value, but all (100%) had pathologically poor responses to the GnRH test. In contrast, all baseline FSH values were raised in group II (mean, 18; range, 11-30 U L-1), indicating toxic injury to the seminiferous tubules. Also in group II the responses to GnRH weer low throughout the test (90%) and there were no clear peak values. In group II, the basal FSH and its maximum response to GnRH were significantly more affected than in group I (P < 0.001). The difference may be due to the effect of the conditioning regimen. Serum basal LH was raised in three of the patients in group I and they also had abnormal releasing test responses. In group II, baseline LH was abnormal in four patients, but the responses to GnRH were normal. However, the maximum responses to the releasing test was significantly more affected in group II (P = 0.024). Serum testosterone levels were normal in all test subjects in both study groups. However, in two patients in both groups, the serum free androgen index was below the low reference limit, and an impaired response of serum testosterone to hCG stimulation was common (60%). CONCLUSIONS: A toxic injury in the testis is common in haematological patients, especially after high-dose chemoradiotherapy. Serum basal testosterone usually remains normal, but even then subnormal serum free androgen index, impaired testosterone response to hCG injection and abnormal response in LH may indicate a deficient androgen status. It may well be that testosterone replacement therapy should be considered in these cases.

Adult↗
PubMed1998

Serum eosinophil cationic protein in the evaluation of asthma severity in children.

To assess the sensitivity and specificity of serum eosinophil cationic protein (ECP) in the diagnosis of asthma and evaluation of asthma severity, we conducted a prospective study to compare parameters of asthma severity, peripheral blood eosinophilia, and serum ECP concentrations in 88 children presenting to a university hospital outpatient clinic with suspected (n=59) or recently diagnosed asthma (n=29). Serum ECP correlated significantly (r[s]=0.676, P = 0.0001) with peripheral eosinophil counts, but only weakly with asthma severity (r[s]=0.21, P=0.046). Serum ECP was significantly higher in atopic children (25+/-11 microg/l) than in nonatopic children (16+/-15 microg/l) (P=0.01). Bronchial hyperresponsiveness had no significant correlation (r[s]= -0.21, P=0.30) with serum ECP. Lung function test results had no (peak flow) or only a weak (FEV1) correlation with serum ECP. In distinguishing between children with and without asthma or in assessing asthma severity, serum ECP is not superior to the peripheral blood eosinophil count. The diagnostic sensitivity and specificity of ECP in serum for detecting symptomatically active asthma, evaluated against the cutoff level of ECP in serum of 16 mg/l, were 54% and 71%, respectively.

Adolescent↗
PubMed1998

Serum total renin levels after ovarian electrocautery in women with polycystic ovary syndrome.

Recent observations have suggested an enhanced activity of the ovarian renin-angiotensin system in polycystic ovary syndrome (PCOS). Owing to technical restrictions, the direct measurement of ovarian renin-angiotensin activity is impossible. The measurement of total renin (active renin + prorenin) in serum is particularly valuable for analyzing the ovarian renin-angiotensin system, as 90% of circulating renin is in the form of prorenin and ovaries are the major extrarenal source of prorenin in females. Also, the renin synthesized by ovaries is in the form of prorenin. In the present study we hypothesized that ovarian trauma caused by electrocautery 'impairs' the activity of the ovarian renin-angiotensin system, which in turn would interrupt the endocrine vicious cycle of PCOS, and restore normal ovarian function. To test this, we examined the effect of ovarian electrocautery on serum levels of total renin in 11 oligomenorrheic women, aged 25 to 36 years, with PCOS and anovulatory infertility. Against our basic hypothesis the serum total renin levels remained unaltered after ovarian electrocautery, while the serum levels of luteinizing hormone, testosterone and androstenedione declined. The mechanism that induces ovulation without altering total renin levels in serum remains to be resolved.

Adult↗
PubMed1997

Cytomegalovirus infection-enhanced cardiac allograft vasculopathy is abolished by DHPG prophylaxis in the rat.

BACKGROUND: A wealth of clinical and experimental evidence exists for cytomegalovirus (CMV) infection as an accelerating factor in the development of cardiac allograft vasculopathy. In this study, the impact of 9-(1,3-dihydroxy-2-propoxymethyl) guanine (DHPG) on rat CMV infection-enhanced cardiac allograft vasculopathy is investigated. METHODS AND RESULTS: Heterotopic rat cardiac allografts were performed from the DA to the WF rat strain, and the recipients were immunosuppressed with cyclosporine A 2 mg.kg-1.d-1 s.c. for a period of 90 days until the end of experiment. Two groups of recipients were infected intraperitoneally with 10(5) plaque-forming units of rat CMV, whereas one group was left noninfected and used as controls. One group of rat CMV-infected rats was treated with DHPG with an initial dose of 20 mg/kg i.p. and a maintenance dose of 10 mg/kg i.p. twice a day from 1 day before transplantation to 30 days after transplantation. Compared with noninfected rats, rat CMV infection was associated with a significant increase in intimal thickening, from 0.68 +/- 0.10 to 1.30 +/- 0.12 score units (P < .01), and double the number of vessels affected (P < .01). DHPG treatment significantly reduced intimal thickening in rat CMV-infected rats, from 1.30 +/- 0.12 to 0.68 +/- 0.13 score units (P < .01), and halved the number of vessels affected (P < .01). CONCLUSIONS: The present results demonstrate that DHPG prophylaxis entirely abolishes the accelerating effect of rat CMV infection on cardiac allograft vasculopathy in immunosuppressed rat recipients, which is consistent with our earlier findings demonstrating a similar effect in nonimmunosuppressed rat aortic allografts. Taken together, these results suggest that DHPG might be useful in the prevention of CMV-accelerated cardiac allograft vasculopathy among heart transplant recipients.

Animals↗
PubMed1997

Effects of acute alcohol ingestion on heart rate variability in patients with documented coronary artery disease and stable angina pectoris.

The effects of acute alcohol intake (ethanol blood concentration 1.3 +/- 0.4%) on heart rate variability were evaluated with 24-hour Holter recordings in 20 patients with stable coronary artery disease in a juice-controlled experiment. In the frequency domain analysis, the high-, low-, and very low frequency components were significantly decreased after alcohol: these changes last longer than the elimination of alcohol.

Adult↗
PubMed1997

Visualization of clinical data with neural networks, case study: polycystic ovary syndrome.

In medicine, the use of neural networks has concentrated mainly on classification problems. Clinicians are often interested in knowing what a patient's status is compared with other similar cases. Compared with biostatistics neural networks have one major drawback: the reliability of the classification is difficult to express. Therefore, clear visualization of the measurements can be more helpful than the calculated probability of a disease. The self-organizing map is the most widely used neural network for data visualization. Although, visualization can be attached to almost any feed-forward network as well. In this paper, we describe a topology-preserving feed-forward network and compare it with the self-organizing map. The two neural network models are used in a case study on the diagnosis of polycystic ovary syndrome, which is a common female endocrine disorder characterized by menstrual abnormalities, hirsutism and infertility.

Adolescent↗
PubMed1997

Heart failure ketosis.

OBJECTIVE: To assess whether blood ketone bodies are increased in congestive heart failure (CHF). METHODS: Thirteen patients with CHF and 11 cardiac patients without CHF took part in the study. Blood acetoacetate and b-hydroxybutyrate levels and the pertinent metabolic and hormonal milieu were measured during 20 h fast and after 2 h glucose infusion. RESULTS: The averaged blood ketone body and free fatty acid levels were significantly higher during the fast and also remained higher after glucose infusion in patients with CHF than in the control group. The areas under ketone body concentration time curve over the last 8 h of the fast were 3522 +/- 662 mumol L-1 h-1 (SE) and 1789 +/- 192 mumol L-1 h-1 in patients with and without CHF, respectively (P = 0.022). Circulating noradrenaline and growth hormone were higher but glucagon lower in patients with CHF than in the controls (P < 0.05 for all differences) whereas the glucose and insulin concentrations were comparable in the study groups. At the time of peak ketonaemia the glucagon-to-insulin ratio was lower in patients with CHF than in patients without CHF (P = 0.04). CONCLUSIONS: These data suggest that severe CHF is a ketosis-prone state. Augmented supply of free fatty acids for ketogenesis due to increased stress hormone-related lipolysis is one likely mechanism.

3-Hydroxybutyric Acid↗