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Featured researches published by Arto Pakarinen.


The New England Journal of Medicine | 1993

Polycystic ovaries and hyperandrogenism in women taking valproate for epilepsy

Jouko I. T. Isojärvi; Timo Laatikainen; Arto Pakarinen; Kaisa Juntunen; Vilho V. Myllylä

Background Reproductive endocrine disorders are more common among women with epilepsy than among normal women. These disorders have been attributed to epilepsy itself, but could be related to antiepileptic-drug therapy. Methods We studied 238 women with epilepsy who were seen regularly at the Outpatient Department of the University Hospital, Oulu, Finland. Their mean age was 33 years (range, 18 to 45), and the mean duration of therapy was 9 years (range, 0 to 31). Twenty-nine (12 percent) were treated with valproate, 120 (50 percent) with carbamazepine, 12 (5 percent) with valproate and carbamazepine, and 62 (26 percent) with other medications; 15 (6 percent) were untreated. Vaginal ultrasonography was performed to determine ovarian size, and serum sex-hormone concentrations were measured in 41 women with epilepsy and menstrual disturbances, 57 women with epilepsy and regular menstrual cycles, and 51 normal women. Results Menstrual disturbances were present in 13 of the women receiving valproate alone (45...


European Journal of Applied Physiology | 2003

Muscle hypertrophy, hormonal adaptations and strength development during strength training in strength-trained and untrained men

Juha P. Ahtiainen; Arto Pakarinen; Markku Alen; William J. Kraemer; Keijo Häkkinen

Hormonal and neuromuscular adaptations to strength training were studied in eight male strength athletes (SA) and eight non-strength athletes (NA). The experimental design comprised a 21-week strength-training period. Basal hormonal concentrations of serum total testosterone (T), free testosterone (FT) and cortisol (C) and maximal isometric strength, right leg 1 repetition maximum (RM) of the leg extensors were measured at weeks 0, 7, 14 and 21. Muscle cross-sectional area (CSA) of the quadriceps femoris was measured by magnetic resonance imaging (MRI) at weeks 0 and 21. In addition, the acute heavy resistance exercises (AHRE) (bilateral leg extension, five sets of ten RM, with a 2-min rest between sets) including blood samples for the determination of serum T, FT, C, and GH concentrations were assessed before and after the 21-week training. Significant increases of 20.9% in maximal force and of 5.6% in muscle CSA in NA during the 21-week strength training period were greater than those of 3.9% and −1.8% in SA, respectively. There were no significant changes in serum basal hormone concentrations during the 21-week experiment. AHRE led to significant acute decreases in isometric force and acute increases in serum hormones both at weeks 0 and 21. Basal T concentrations (mean of 0, 7, 14 and 21 weeks) and changes in isometric force after the 21-week period correlated with each other (r=0.84, P<0.01) in SA. The individual changes in the acute T responses between weeks 0 and 21 and the changes in muscle CSA during the 21-week training correlated with each other (r=0.76, P<0.05) in NA. The correlations between T and the changes in isometric strength and in muscle CSA suggest that both serum basal testosterone concentrations and training-induced changes in acute testosterone responses may be important factors for strength development and muscle hypertrophy.


Journal of Strength and Conditioning Research | 2005

Short vs. long rest period between the sets in hypertrophic resistance training: influence on muscle strength, size, and hormonal adaptations in trained men.

Juha P. Ahtiainen; Arto Pakarinen; Markku Alen; William J. Kraemer; Keijo Häkkinen

Acute and long-term hormonal and neuromuscular adaptations to hypertrophic strength training were studied in 13 recreationally strength-trained men. The experimental design comprised a 6-month hypertrophic strength-training period including 2 separate 3-month training periods with the crossover design, a training protocol of short rest (SR, 2 minutes) as compared with long rest (LR, 5 minutes) between the sets. Basal hormonal concentrations of serum total testosterone (T), free testosterone (FT), and cortisol (C), maximal isometric strength of the leg extensors, right leg 1 repetition maximum (1RM), dietary analysis, and muscle cross-sectional area (CSA) of the quadriceps femoris by magnetic resonance imaging (MRI) were measured at months 0, 3, and 6. The 2 hypertrophic training protocols used in training for the leg extensors (leg presses and squats with 10RM sets) were also examined in the laboratory conditions at months 0, 3, and 6. The exercise protocols were similar with regard to the total volume of work (loads 3 sets 3 reps), but differed with regard to the intensity and the length of rest between the sets (higher intensity and longer rest of 5 minutes vs. somewhat lower intensity but shorter rest of 2 minutes). Before and immediately after the protocols, maximal isometric force and electro-myographic (EMG) activity of the leg extensors were measured and blood samples were drawn for determination of serum T, FT, C, and growth hormone (GH) concentrations and blood lactate. Both protocols before the experimental training period (month 0) led to large acute increases (p < 0.05–0.001) in serum T, FT, C < and GH concentrations, as well as to large acute decreases (p < 0.05–0.001) in maximal isometric force and EMG activity. However, no significant differences were observed between the protocols. Significant increases of 7% in maximal isometric force, 16% in the right leg 1RM, and 4% in the muscle CSA of the quadriceps femoris were observed during the 6-month strength-training period. However, both 3-month training periods performed with either the longer or the shorter rest periods between the sets resulted in similar gains in muscle mass and strength. No statistically significant changes were observed in basal hormone concentrations or in the profiles of acute hormonal responses during the entire 6-month experimental training period. The present study indicated that, within typical hypertrophic strength-training protocols used in the present study, the length of the recovery times between the sets (2 vs. 5 minutes) did not have an influence on the magnitude of acute hormonal and neuromuscular responses or long-term training adaptations in muscle strength and mass in previously strength-trained men.


Neurology | 2004

Effect of epilepsy and antiepileptic drugs on male reproductive health.

Jouko I. T. Isojärvi; E. Löfgren; K. S.T. Juntunen; Arto Pakarinen; M. Päivänsalo; I. Rautakorpi; L. Tuomivaara

Background: Men with epilepsy have reduced fertility, and antiepileptic drugs may affect semen quality. Moreover, animal studies suggest that valproate (VPA) may be associated with testicular atrophy. Objective: To evaluate reproductive function in men with epilepsy. Methods: Sixty men with epilepsy and 41 control men were evaluated for their reproductive health. Fifteen men were taking carbamazepine (CBZ) and 18 men oxcarbazepine (OXC) for partial epilepsy, and 27 men were taking VPA for generalized epilepsy. Reproductive hormones were assayed from serum samples, semen analysis and ultrasonography of the testicles were performed, and testicular volume was calculated. Results: Men on CBZ had low serum dehydroepiandrosterone sulfate concentrations (p < 0.001), and men on VPA had high concentrations of serum androstenedione (p < 0.001). The frequency of morphologically abnormal sperm was higher among CBZ-treated (p < 0.01), OXC-treated (p < 0.05), and VPA-treated men (p < 0.01) than among the control men. Moreover, both CBZ and VPA were associated with poor motility of sperm (p < 0.05). In addition, the frequency of abnormally low sperm concentration was high in men on CBZ (p < 0.001), and the frequency of any sperm abnormality was high in men on VPA (p < 0.01). The VPA-treated men with abnormal sperm had smaller testicular volumes than the control men (p = 0.003). Conclusions: CBZ, OXC, and VPA are associated with sperm abnormalities in men with epilepsy. In addition, VPA-treated men with generalized epilepsy who have abnormal sperm may have reduced testicular volume.


Neurology | 2001

Reproductive effects of valproate, carbamazepine, and oxcarbazepine in men with epilepsy

J. Rättyä; J. Turkka; Arto Pakarinen; M. Knip; M. Kotila; O. Lukkarinen; Vilho V. Myllylä; Jouko I. T. Isojärvi

Background: Recent observations have indicated that reproductive endocrine disorders are common among women taking valproate (VPA) for epilepsy, but it is not known whether respective abnormalities develop in men taking VPA for epilepsy. Carbamazepine (CBZ) may induce endocrine disorders in men with epilepsy, but the endocrine effects of oxcarbazepine (OXC) are not known. Methods: Reproductive endocrine function was evaluated in 90 men taking VPA (n = 21), CBZ (n = 40), or OXC (n = 29) as monotherapy for epilepsy and in 25 healthy control men. Results: Twelve men (57%) taking VPA had increased serum androgen levels. The mean serum level of androstenedione was high in patients taking VPA. Serum levels of dehydroepiandrosterone sulfate were low, and serum concentrations of sex hormone–binding globulin (SHBG) were high in men taking CBZ. The endocrine effects of OXC seemed to be dose-dependent, because serum hormone levels were normal in patients with low OXC doses (<900 mg/day), but serum concentrations of testosterone, gonadotropins, and SHBG were high in patients with a daily OXC dose ≥900 mg. Conclusions: VPA increases serum androgen concentrations in men with epilepsy. The endocrine effects of CBZ and OXC were different, because CBZ appears to decrease the bioactivity of androgens, whereas OXC does not.


Annals of Neurology | 1999

Valproate-induced hyperandrogenism during pubertal maturation in girls with epilepsy.

Leena Vainionpää; Johanna Rättyä; M. Knip; Juha S. Tapanainen; Arto Pakarinen; Peter Lanning; A. Tekay; Vilho V. Myllylä; Jouko I. T. Isojärvi

Valproate is effective for treatment of a variety of seizure types both in adults and in children with epilepsy, but it induces obesity and polycystic ovaries in a considerable proportion of adult women, particularly when the medication is started before the age of 20. In the present study we evaluated reproductive endocrine function in 41 girls, 8 to 18 years old, taking valproate for epilepsy and in 54 healthy control girls. Among the girls taking valproate, 16 were prepubertal, 11 were pubertal, and 14 were postpubertal, and the corresponding numbers were 20, 13, and 21 in the control group. The mean serum testosterone concentrations of prepubertal, pubertal, and postpubertal girls taking valproate were significantly higher than those of the control girls at the same pubertal stage. Hyperandrogenism, defined as serum testosterone levels higher than the mean + 2SD in the control girls at the same pubertal stage, was seen in 38% of prepubertal, 36% of pubertal, and 57% of postpubertal girls taking valproate. In addition, postpubertal girls taking valproate were more obese than the controls and the mean serum insulin‐like growth factor binding protein‐1 concentration of pubertal and postpubertal hyperandrogenic girls taking valproate was lower than in valproate‐treated girls without hyperandrogenism. Valproate may induce hyperandrogenism in girls with epilepsy during the sensitive period of pubertal maturation, and the frequency of hyperandrogenism increases with pubertal development. This emphasizes the importance of careful endocrine observation of girls taking valproate for epilepsy. Ann Neurol 1999;45:444–450


Journal of Strength and Conditioning Research | 2005

Acute hormonal responses to submaximal and maximal heavy resistance and explosive exercises in men and women.

Vesa Linnamo; Arto Pakarinen; Paavo V. Komi; William J. Kraemer; Keijo Häkkinen

The purpose of this study was to examine acute hormonal and neuromuscular responses in men and women to 3 heavy resistance but clearly different exercise protocols: (a) submaximal heavy resistance exercise (SME), (b) maximal heavy resistance exercise (HRE), and (c) maximal explosive resistance exercise (EE). HRE included 5 sets of 10 repetition maximum (10RM) situps, bench press, and bilateral leg extensions (David 210 machine) with a 2-minute recovery between the sets. In SME, the load was 70%, and in EE, the load was 40% from that used in HRE. A significant increase (p < 0.05) in serum growth hormone (GH) was observed after HRE both in men and women, but the increase was greater (p < 0.05) in men than in women. Serum testosterone (T) increased significantly (p < 0.05) only during HRE in men. Since GH and T are anabolic hormones, the acute exercise-induced response during HRE may play an important role in the long-term anabolic adaptation processes related to muscle hypertrophy and maximal strength development.


The American Journal of Medicine | 2001

Altered ovarian function and cardiovascular risk factors in valproate-treated women.

Jouko I. T. Isojärvi; Erik Taubøll; Arto Pakarinen; Johan van Parys; Johanna Rättyä; Hanne F. Harbo; Per O Dale; Bart C.J.M. Fauser; Leif Gjerstad; Riitta Koivunen; M. Knip; Juha S. Tapanainen

PURPOSE Polycystic ovaries and menstrual disturbances seem to be common among women taking valproate for epilepsy. The purpose of the present study was to assess the frequency of valproate-related metabolic and endocrine disorders in different groups of women with epilepsy. SUBJECTS AND METHODS Seventy-two women with epilepsy and 52 control subjects from centers in three European countries (Finland, Norway, and the Netherlands) participated in the study. Thirty-seven of the women with epilepsy were taking valproate monotherapy and 35 carbamazepine monotherapy. RESULTS The frequency of polycystic ovaries or hyperandrogenism, or both, among valproate-treated women with epilepsy was 70% (26 of 37) compared with 19% (10 of 52) among control subjects (P <0.001). They were found in 79% (11 of 14) of obese and 65% (15 of 23) of lean women on valproate, and in 20% (7 of 35) of carbamazepine-treated women. The obese valproate-treated women with polycystic ovaries or hyperandrogenism, or both, had hyperinsulinemia and associated unfavorable changes in serum lipid levels consistent with insulin resistance. CONCLUSIONS Polycystic ovaries and related hyperandrogenism are frequently encountered in both obese and lean women taking valproate for epilepsy. The use of valproate is associated with risk factors for cardiovascular disease in obese women.


European Journal of Applied Physiology | 1988

Neuromuscular and hormonal responses in elite athletes to two successive strength training sessions in one day

Keijo Häkkinen; Arto Pakarinen; Markku Alen; Heikki Kauhanen; Paavo V. Komi

SummaryAcute neuromuscular and endocrine adaptations to weight-lifting were investigated during two successive high intensity training sessions in the same day. Both the morning (I) (from 9.00 to 11.00 hours) and the afternoon (II) (from 15.00 hours to 17.00 hours) training sessions resulted in decreases in maximal isometric strength (p<0.01 and <0.05), shifts (worsening) in the force-time curve in the absolute scale (p<0.05 and ns.) and in decreases in the maximal integrated EMG (p<0.01 and <0.05) of the selected leg extensor muscles. Increases in serum total (p<0.05) and free testosterone (p<0.01) and in cortisol (p<0.01) concentrations were found during training session II. These were followed by decreases (p<0.001 andp<0.01 and ns.) in the levels of these hormones one hour after the termination of the session. The responses during the morning training session were different with regard to the decreases in serum total testosterone (p<0.05), free testosterone (ns.) and cortisol (p<0.05). Only slight changes were observed in the levels of luteinizing hormone and sex hormone-binding globulin during the training sessions. Increases (p<0.01) took place in somatotropin during both training sessions. The present findings suggest that high intensity strengthening exercises may result in acute adaptive responses in both the neuromuscular and endocrine systems. The diurnal variations may, however, partly mask the exercise-induced acute endocrinological adaptations in the morning. Recording of muscle activation and muscle strength and analysis of certain serum hormone concentrations with sufficient frequency during the training process may be useful in optimizing and controlling the contents of individual training sessions and the full training program.


Epilepsia | 2002

Serum Insulin and Leptin Levels in Valproate‐associated Obesity

Virpi Pylvänen; Mikael Knip; Arto Pakarinen; Mervi Kotila; Jukka Turkka; Jouko I. T. Isojärvi

Summary:  Purpose: Weight gain is an important adverse effect of valproate (VPA) therapy, and it is associated with hyperinsulinemia and hyperandrogenism in women with epilepsy. Leptin is considered a signaling factor regulating body weight and energy metabolism. In human subjects, obesity is in general associated with elevated serum leptin levels, suggesting decreased sensitivity to leptin. The present study aimed at evaluating the role of insulin and leptin in VPA‐related obesity.

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Keijo Häkkinen

University of Jyväskylä

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Markku Alen

Oulu University Hospital

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Paavo V. Komi

University of Jyväskylä

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Antti Mero

University of Jyväskylä

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Mikael Knip

University of Helsinki

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