Pirkko Huttunen

The occurrence of brown adipose tissue in outdoor workers.

SummaryHistochemical reactions and activities of mitochondrial enzymes in adipose tissue around the neck arteries and in pericardium were studied in men who had been outdoor workers in northern Finland. The purpose was to study the occurrence of brown fat in workers having been exposed to cool or cold ambient temperature. Indoor workers of the same age were used as controls.Histochemically, no mitochondrial enzyme reactions were seen in the adipose tissues taken from the indoor workers, whereas some outdoor workers had some multilocular adipose tissue, mostly around the neck arteries. Biochemical parameters also showed increased enzyme activities of aerobic energy metabolism in the adipose tissue of these people.The present results suggest that working in the cold can retain brown adipose tissue in “strategic” places in human adults.

Effects of marathon running on running economy and kinematics

Abstract The present study was designed to investigate interactions between running economy and mechanics before, during, and after an individually run marathon. Seven experienced triathletes performed a 5-min submaximal running test on a treadmill at an individual constant marathon speed. Heart rate was monitored and the expired respiratory gas was analyzed. Blood samples were drawn to analyze serum creatine kinase activity (S-CK), skeletal troponin I (sTnI), and blood lactate (B-La). A video analysis was performed (200 frames · s−1) to investigate running mechanics. A kinematic arm was used to determine the external work of each subject. The results of the present study demonstrate that after the marathon, a standardized 5-min submaximal running test resulted in an increase in oxygen consumption, ventilation, and heart rate (P < 0.05), with a simultaneous decrease in the oxygen difference (%) between inspired and expired air, and respiratory exchange ratio (P < 0.05). B-La did not change during the marathon, while sTnI and S-CK values increased (P < 0.05), peaking 2 h and 2 days after the marathon, respectively. With regard to the running kinematics, a minor increase in stride frequency and a similar decrease in stride length were observed (P < 0.01). These results demonstrate clearly that weakened running economy cannot be explained by changes in running mechanics. Therefore, it is suggested that the increased physiological loading is due to several mechanisms: increased utilization of fat as an energy substrate, increased demands of body temperature regulation, and possible muscle damage.

Effects of long‐term whole‐body cold exposures on plasma concentrations of ACTH, beta‐endorphin, cortisol, catecholamines and cytokines in healthy females

Objective. Cold therapy is used to relieve pain and inflammatory symptoms. The present study was designed to determine the influence of long‐term regular exposure to acute cold temperature. Two types of exposure were studied: winter swimming in ice‐cold water and whole‐body cryotherapy. The outcome was investigated on humoral factors that may account for pain alleviation related to the exposures. Material and methods. During the course of 12 weeks, 3 times a week, a group of healthy females (n = 10) was exposed to winter swimming (water 0–2°C) for 20 s and another group (n = 10) to whole‐body cryotherapy (air −110°C) for 2 min in a special chamber. Blood specimens were drawn in weeks 1, 2, 4, 8 and 12, on a day when no cold exposure occurred (control specimens) and on a day of cold exposures (cold specimens) before the exposures (0 min), and thereafter at 5 and 35 min. Results. Plasma ACTH and cortisol in weeks 4–12 on time‐points 35 min were significantly lower than in week 1, probably due to habituation, suggesting that neither winter swimming nor whole‐body cryotherapy stimulated the pituitary‐adrenal cortex axis. Plasma epinephrine was unchanged during both experiments, but norepinephrine showed significant 2‐fold to 3‐fold increases each time for 12 weeks after both cold exposures. Plasma IL‐1‐beta, IL‐6 or TNFα did not show any changes after cold exposure. Conclusions. The main finding was the sustained cold‐induced stimulation of norepinephrine, which was remarkably similar between exposures. The frequent increase in norepinephrine might have a role in pain alleviation in whole‐body cryotherapy and winter swimming.

Long-term alcohol consumption and brown adipose tissue in man.

SummaryThe purpose of the present work was to study whether long-term alcohol consumption in man affects the develeopment of brown adipose tissue. The adipose tissue around the thoracic aorta and common carotid arteries was collected at medicolegal autopsies on adults with a positive record of heavy alcohol consumption. Adults without any evident history of alcohol consumption served as controls. Histochemical reactions of the oxidative mitochondrial enzymes, cytochrome oxidase and succinate dehydrogenase were studied in samples of this adipose tissue and the activities of the enzymes were measured biochemically.There was histological evidence of some multilocular adipose tissue around the thoracic aorta and common carotid arteries of the alcohol consumers, whereas the adipose tissue from the non-drinkers was mostly unilocular resembling white adipose tissue. Histochemical evidence of brown adipose tissue was found in all alcohol consumers, but also in some of the controls. Biochemical cytochrome oxidase (CYO) and succinate dehydrogenase measurements in isolated mitochondria showed activity in 70% of the cases of drinkers and in one of the eight controls. Activity of CYO was measurable in the mitochondria from two other controls. The protein content of the samples from the alcoholics was twice that of the controls. The results suggest that chronic alcohol intake may induce a change in the white adipose tissue around the thoracic aorta and common carotid arteries of human adults into brown fat.

Resistance exercise-induced hormonal responses in men, women, and pubescent boys

PURPOSE This study was designed to investigate the acute plasma catecholamine (CA) response to resistance exercise and its association with serum testosterone (TES), cortisol (COR), and growth hormone (GH) concentration changes. METHODS Six men, six women, and six adolescent boys (14 +/- 0 yr) performed five sets of 10 knee extensions with 40% of one-repetition maximum followed by two sets performed to exhaustion. Arterialized venous blood was sampled before, during, and after the exercise for the hormone analysis. External work performed (Wext), average EMG normalized for maximal EMG, exercise-induced maximal voluntary contraction decline, and plasma volume change (deltaPV) were also determined. RESULTS No differences between groups were observed in Wext relative to lean body mass, average EMG, or in exercise-induced fatigue. Plasma norepinephrine (NE) concentrations were similar in the three groups. However, peak plasma epinephrine (E) increase from preexercise was about twice as high in boys (5.0 +/- 2.6 nmol.L-1 as in men (2.5 +/- 0.8 nmol.L-1] and in women (2.1 +/- 0.6 nmol.L-1) (P < 0.05). The deltaPV could explain a significant increase in serum TES concentration in men, and increases in GH concentrations in every group, but not that of COR observed only in boys. No correlation between the CA concentration changes and those of the other hormones were observed even if the groups were combined. CONCLUSION No associations between the CA and the other hormone responses were observed. However, the results may suggest a trend for higher stress response to this particular exercise in the boys than in adults.

Increased Urinary Concentration of Catecholamines in Hypothermia Deaths

Observations are presented on 24 hypothermia deaths, either accidental or suicidal. Most cases occurred in dry, cold circumstances, the air temperature being below 0 degree C. More cases were seen in early winter, suggesting a lack of acclimatization to the cold. Purple skin and swelling of the ears and nose (mild frostbite) were the most frequent external signs of exposure. Frequent internal signs were stomach ulcerations or hemorrhagic gastritis and small degenerative foci in the myocardium. High blood alcohol (about 200 mg/dL) was the most common contributory factor, but psychotropic drugs were detected in a few cases. The total urinary catecholamine content was increased in the hypothermia deaths, with levels of 0.20 +/- 0.16 microgram/mL (mean +/- standard deviation) versus 0.07 +/- 0.07 microgram/mL in sudden natural deaths and 0.02 +/- 0.02 microgram/mL in rapid violent deaths. Adrenaline was more abundant than noradrenaline. It is suggested that urine catecholamine measurements can give useful information for the diagnosis of acute hypothermia.

Hypothermia markers: serum, urine and adrenal gland catecholamines in hypothermic rats given ethanol

The effect of ethanol (2 g/kg) on body temperature and catecholamine (CA) secretion in the cold (-20 degrees C) was investigated in adult male and female rats. The temperature dropped more rapidly in the females, being approximately 10 degrees C after 3 h as compared with 18 degrees C in the males. Controls received the same dose of ethanol but were kept at +20 degrees C. Increased concentrations of adrenaline (A) and noradrenaline (NA) were already observed in the serum and urine of the females after 0.5 h of exposure, but at 1 h in the males. Serum values were low in the females after 2 and 3 h and urine values high in connection with the deep hypothermic state. The urine values of the males were also high at the end of exposure, when they, too, were hypothermic. Depletion of amines was observed in the adrenals during the hypothermia phase, while CA concentrations tended to rise in the serum of the rats kept in the warm. The CA index (A:NA) was generally > 1 in both the serum and urine of the cold-exposed rats. The results show that female rats are less resistant to hypothermia than males, as indicated by their more rapid drop in body temperature and exhaustion of CA secretion. It is also apparent that urine CAs are worth measuring in cases of accidental hypothermia and possibly also other types of stress. An elevated CA index (> 1) seems to be an additional marker of hypothermia, showing a proportionally greater increase in the secretion of A than NA during cold stress.

Anatomical localization in hippocampus of tetrahydro-β-carboline-induced alcohol drinking in the rat

Guide cannulae for unilateral or bilateral micro-injection were implanted stereotaxically into the dorsal hippocampus of the male adult Sprague-Dawley rat. Following post-operative recovery, the animals individual preference for ethyl alcohol in concentrations from 3-30% (v/v) was tested over a 9-day period by a three-bottle, two-choice technique. Following this pre-screen, 3.0 microliter of 1,2,3,4-tetrahydro-beta-carboline (TH beta C) hydrochloride, a benzodiazepine receptor antagonist, was infused in a concentration of 25-200 ng into the hippocampus of each unrestrained rat twice a day for three to six days. After the first two days of infusion, the 9-day preference test for alcohol drinking was begun and continued identically as in the earlier test. A third alcohol preference test during which no injections were given was conducted at an interval of two weeks following the second. The micro-injection of TH beta C into certain sites in the hippocampus enhanced alcohol consumption from 0.5-2.0 g/kg during the 9-day test interval. The magnitude of this elevated intake was dependent on the site of infusion and was more pronounced when intermediate concentrations of 7-12% alcohol were offered to the rat. At sites in coronal planes encompassing AP 3.0 and AP 3.5, the micro-injection of TH beta C enhanced alcohol drinking significantly in 75% of the animals; however, when delivered at sites in coronal planes AP 1.0 through AP 2.5, TH beta C augmented alcohol drinking significantly in 15% of the rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic alcohol intake induces the oxidative capacity of brown adipose tissue in the rat

The present study was carried out to elucidate the effect of long-term alcohol intake on the oxidative capacity of brown adipose tissue in the rat. Rats housed at room temperature were given water containing 10% ethanol for six months, while controls received water alone. Fully cold-acclimated rats (exposed to +4 degrees C for 6 weeks) served as the second control group. Alcohol did not alter the food intake of the rats compared with the controls kept at room temperature, but it did cause a mean decrease of 8 ml in fluid consumption. There was no difference in the increase in body weight between the groups housed at room temperature. Body weight of the rats exposed to cold did not change during cold acclimation. No morphological liver changes were observed in alcohol-fed rats, but some changes related to long-term alcohol consumption were found in the myocardium. Chronic alcohol intake increased the quantity of brown adipose tissue and its protein content but changes were not as great as in the cold-acclimated rats nor did alcohol increase protein content per unit of the adipose tissue as did cold. On the other hand, the specific activity of mitochondrial cytochrome oxidase increased by 90% and that of succinate dehydrogenase by 130% in alcohol-fed rats, whereas specific activities of these enzymes displayed little or no change in the cold-acclimated rats. Results suggest that chronic alcohol ingestion induces the oxidative capacity of the interscapular brown adipose tissue in the rat, increasing the mass of BAT and specific activities of mitochondrial enzymes.

Winter swimming improves general well-being

Objectives. This study deals with the effects of regular winter swimming on the mood of the swimmers. Methods. Profile of Mood State (POMS) and OIRE questionnaires were completed before (October) and after (January) the fourmonth winter swimming period. Results. In the beginning, there were no significant differences in the mood states and subjective feelings between the swimmers and the controls. The swimmers had more diseases (about 50%) diagnosed by a physician. Tension, fatigue, memory and mood negative state points in the swimmers significantly decreased with the duration of the swimming period. After four months, the swimmers felt themselves to be more energetic, active and brisk than the controls. Vigour-activity scores were significantly greater (p < 0.05). All swimmers who suffered from rheumatism, fibromyalgia, or asthma, reported that winter swimming had relieved pains. Conclusion. Improvement of general well-being is thus a benefit induced by regular winter swimming. (Int J Circumpolar Health 2004; 63(2):140–144)