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Biomedical subjects

J Hassi

Publications and source records attributed to J Hassi.

At least 37 records · Page 2Linked to original sources
PubMed1998

Heat balance at -5 degrees C after cold water immersion.

Two different possible behaviors at -5 degrees C after cold water immersion were studied. A test subject wearing winter clothing walked (5 km/h) on a treadmill for 45 minutes at -5 degrees C and at a wind velocity of 3 m/s with dry clothing, immediately after a thorough immersion in 5 degrees C water, or after immersion and wringing, freezing, and beating of the clothing (to remove ice). A marked heat debt (ca. 1000 kJ) was measured at the end of the cold water immersion. Attempts to dry the clothing caused an additional heat debt of ca. 300 kJ. After 45 minutes walking, the difference in heat depth between the treatments was nearly the same as before the exercise. The difference in clothing weight was only 0.9 kg between the two treatments after walking. Beating frozen clothing items could remove ice corresponding to only 0.7% of the wet weight of the clothing. Results suggest that after cold water immersion in winter, the undressing procedure could not be recommended. Instead, after initially removing boots, mittens, and hat, the subject should start walking. The water accumulated in boots and mittens should be poured out when necessary.

Adult↗
PubMed1997

Chronic Chlamydia pneumoniae infection is associated with a serum lipid profile known to be a risk factor for atherosclerosis.

Chlamydia pneumoniae infection has been associated with coronary heart disease. To evaluate the mechanisms of this association, we studied whether chronic C. pneumoniae infection affects serum lipid values similarly to acute infections. Triglyceride, total and HDL cholesterol concentrations, and C. pneumoniae antibodies were measured from paired serum samples of 415 Finnish males taken 3 years apart. Chronic infection, defined as persistent IgG and IgA antibodies, was found in 20%, and the antibodies were negative (IgG < 32 and IgA < 16 in both samples) in 15% of the cases studied. The serum triglyceride and total cholesterol concentrations were higher in the subjects with a chronic C. pneumoniae infection than in the subjects with no antibodies (1.23 versus 1.03 mmol/L and 6.41 versus 6.31 mmol/L, respectively). The HDL cholesterol concentrations and the ratios of HDL cholesterol to total cholesterol were significantly decreased in the subjects with chronic infection (1.24 versus 1.36 mmol/L, P = .026; and 0.19 versus 0.22, P = .018, respectively). Chronic C. pneumoniae infection seems to be associated with a serum lipid profile considered to increase the risk of atherosclerosis. This finding supports the hypothesis that infections play a role in the pathogenesis of atherosclerosis.

Adolescent↗
PubMed1997

Chlamydia pneumoniae and Helicobacter pylori infections in Sámi and Finnish reindeer herders.

The Sámi people in northernmost Finland have lower mortality from cardiovascular diseases than the main population of Finland. Chronic infections caused by Chlamydia pneumoniae and Helicobacter pylori, both quite recently discovered gram-negative bacteria, have been associated with atherosclerosis. We studied the prevalence of these infections in Sámi and Finnish men by analysing the C. pneumoniae and H. pylori specific serum IgG and IgA antibodies using microimmune fluorescence and enzyme linked immunosorbent assay methods, respectively. The frequency of C. pneumoniae IgG antibodies and the age adjusted geometric mean titres differed significantly between these groups. The Finns were more often sero-positive than the Sámi (76% vs. 67%, respectively), the age adjusted geometric mean titre being 71.6 in the Finns and 38.3 in the Sámi; p = 0.001. No significant difference was found in the H. pylori IgG and IgA antibody prevalences, nor in the geometric mean titres between these groups. The difference in cardiovascular mortality between the Sámi and Finns may be partly explained by the lower incidence of chlamydial infections in the Sámi.

Adult↗
PubMed1995

Association of blood cadmium to the area of residence and hypertensive disease in Arctic Finland.

The association of cadmium exposure with area of residence, blood pressure, and arterial hypertensive disease was examined in 230 reindeer herders in northernmost arctic Finland. Blood cadmium concentration averaged 10.0 nmol/l, and was three times higher in smokers than in nonsmokers (16.7 vs. 5.5 nmol/l). Concentrations increased from the southwestern to the northeastern area west of the Kola Peninsula, Russia, both in nonsmokers (3.1 vs. 6.8 nmol/l) and smokers (10.8 vs. 32.0 nmol/l). High cadmium levels were most common in the northeast: 32% of the values were at least 15 nmol/l, 10% at least 45 nmol/l (health-based limit of WHO), and 3% at least 90 nmol/l (the critical limit for renal damage). High cadmium concentration was associated with a rise in blood pressure; the rise was particularly pronounced in subjects with hypertensive diseases. These associations were not affected by age, body mass index, smoking, and alcohol consumption. The results suggest that cadmium exposure may have harmful health effects in arctic Finland and emphasize the importance of reducing pollution from industrial sources in the Kola Peninsula.

Adult↗
PubMed1995

High serum alpha-tocopherol, albumin, selenium and cholesterol, and low mortality from coronary heart disease in northern Finland.

OBJECTIVES: The mortality from coronary heart disease (CHD) is exceptionally low in northernmost Finland, the Sámi (formerly known as Lapp) area. To clarify the reasons for this, the levels of serum cholesterol, other classic risk factors, and major antioxidants, alpha-tocopherol, retinol, albumin and selenium were determined in males living in the low-mortality area and in a reference area. DESIGN: A health survey amongst reindeer herdsmen living in the three northernmost communes of Finland (the Sámi area) and in the six neighbouring communities to the south (the reference area). The mortality from CHD in the two areas was determined from death certificates issued during the period 1981-1990. SUBJECTS: A total of 350 participants of the health survey, mean age 46 (SD 14) years. RESULTS: The mortality from CHD was 17% lower in the Sámi area than in the reference area [95% confidence interval (CI) for the difference: 4-29]. Subjects living in the low-mortality area showed higher serum-lipid-adjusted alpha-tocopherol (18.4 vs. 16.1 mumol L-1; 95% CI for difference: 0.7-3.9; P < 0.001), albumin (46.9 vs. 46.2 g L-1; 0.2-1.3; P < 0.02), selenium (1.59 vs. 1.47 mumol L-1; 0.02-0.22; P < 0.02), cholesterol (6.76 vs. 6.34 mmol L-1; 0.12-0.72; P < 0.001) and LDL cholesterol (4.76 vs. 4.45 mmol L-1; 0.05-0.57; P < 0.02) than those in the reference area. The HDL cholesterol:cholesterol ratio was lower in the Sámi area than in the reference area (0.20 vs. 0.21; -0.02-0.00; P < 0.04). The Sámis showed higher serum selenium than the Finns. Serum alpha-tocopherol increased with the consumption of reindeer meat and serum selenium increased with fish consumption. CONCLUSIONS: Alpha-tocopherol, albumin and selenium may play a role in the low mortality from CHD observed in northernmost Finland. The favourable serum antioxidant status in northerners may be credited to the local diet.

Adult↗
PubMed1995

Cooling-induced changes in muscular performance and EMG activity of agonist and antagonist muscles.

The effect of whole body cooling on the muscular performance and electromyographic (EMG) activity of agonist and antagonist muscles during dynamic exercise was studied. Eleven slightly clothed male subjects were exposed to ambient temperatures of 27 degrees C and 10 degrees C for 60 min. After the exposures the subjects performed an overhead ball throwing test. Five balls, weighing from 0.3 kg to 3.0 kg were thrown and the velocity of the balls was measured. The EMG activity of two agonist-antagonist muscle pairs (m. triceps brachii--m. deltoideus and m. rectus abdominis--m. erector spinae) were measured during throwing. Cooling decreased mean skin temperature by 6.3 +/- 0.5 degree C (mean +/- SE). The temperature of m. triceps brachii decreased by 4.0 +/- 1.6 degrees C and 1.8 +/- 0.6 degrees C from the depth of 20 and 30 mm underneath the skin surface, respectively. The corresponding values of m. deltoideus were 5.1 +/- 0.4 degrees C and 3.2 +/- 0.8 degrees C. The cooling-induced decrement in ball velocity varied from 9.4 +/- 3.3% (0.3-kg ball) to 5.6 +/- 2.8% (3.0-kg ball) (p < 0.001-0.01). After cooling, the time to reach the maximal level of integrated electromyographic (IEMG) activity in m. triceps brachii (agonist) was increased (30-42%, p < 0.05-0.001). Moreover, cooling decreased the mean IEMG activity m. triceps brachii, while the activity of m. deltoideus (antagonist) was increased. The alteration was significant (p < 0.05-0.001) with the three lightest balls.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Cold and mortality from ischaemic heart disease in northern Finland.

Mortality from ischaemic heart disease (IHD) in northern Finland was examined on a regional basis, correlating that observed in the general male population with environmental temperature and individual risk factors (smoking, serum lipids and blood pressure) as available from a health survey of 571 rural men. The age-adjusted mortality from IHD increased by 5% (95 C.I. 1-9%) per 1 degree C decline in January mean temperature, but this finding was largely due to high mortality in a single commune (Kittilä). The probability that a subject was living in this high mortality area increased by a factor of 16 (95% C.I. 4-58) per 1 degree C decline in temperature and was 5-fold in smokers as compared with non-smokers. The findings conform with previous reports claiming that climate is one factor contributing to regional differences in IHD.

Adult↗
PubMed1995

High serum concentrations of vitamin E and cholesterol and low mortality from ischaemic heart disease in northern Finland.

The regional mortality from ischaemic heart disease varies from low to high in northern Finland. To clarify the reasons for this 361 men engaged in reindeer herding who lived in the northernmost part of the country, the Sámi area, or a neighbouring reference area were investigated. The mortality from IHD in the general population was lower in the Sámi area than the reference area. The serum lipid-adjusted vitamin E (alpha tocopherol) and cholesterol showed reverse trends, being higher in the Sámi area. Serum vitamin E increased with the consumption of reindeer meat. A diet-associated good vitamin E status may be one factor in the anomalous, low mortality from IHD in the North in a population with high serum cholesterol.

Cholesterol↗
PubMed1994

Season and mental illness in an Arctic area of northern Finland.

The seasonal variation in mental disturbances was examined in 1251 reindeer herding males in an arctic area of northern Finland using the psychiatric section of the Cornell Medical Index questionnaire (CMI-MR). The mean age of subjects was 43 years. One third of them were full-time reindeer herders and 1/10 were Lapps. The prevalence of mental disorders (CMI-MR at least 5) was estimated at 14%, and it showed peaks in spring and autumn. The pattern was repeated for different varieties of illness, except for depression which showed a single cycle with the highest prevalence in the light season. The authors conclude that mental disorders in the arctic are most common in spring and autumn, and they question the common belief in mid-winter as the most common season for mental disorders.

Adolescent↗
PubMed1994

Snowmobile driving and symptoms of the locomotive organs.

The role of snowmobile driving as a factor in symptoms of the locomotive organs was examined in 1,793 reindeer herding men using a postal questionnaire. Thirty-eight % of the respondents reported troubles in the upper limbs and shoulders which according to their own judgement were caused by snowmobile driving, and 34% reported such symptoms in the knees and 42% in the back. Aching, pain or tenderness upon movement in at least one joint during the current year, inquired by independent questions, were reported by 46% of the men. The prevalence of joint symptoms felt in the elbow (reported by 15% of the subjects), wrist (13%), fingers (10%), shoulder (22%) and knees (20%) increased by a factor of 1.6-2.5 from those driving a snowmobile 1-20 days a year to those driving 150 days or more. The findings confirm earlier reports of increased occurrence of symptoms in the locomotive organs in snowmobile drivers and justify technical and other preventive measures.

Adult↗
PubMed1993

Responses to whole body and finger cooling before and after an Antarctic expedition.

Eight subjects, who were indoor workers and not habitually exposed to cold, spent 53 days in Antarctica. They did mainly geological field work often requiring the use of bare hands. The effects of the expedition on responses to a whole body cold exposure test, a finger blood flow test and a cold pressor test were studied. After the expedition, during whole-body cooling the time for the onset of shivering was delayed by 36 min (P < 0.001) and forearm and thigh temperatures were 1.5 degrees C higher (P < 0.05) at the end of exposure. During local cooling of the finger with 10 degrees C perfusion, finger vascular resistance was 14.9 (SEM 6.6) mmHg.ml-1.min.100 ml (P < 0.05) lower and finger temperature 3.9 (SEM 0.8) degrees C higher (P < 0.01). However, the decrease in rectal temperature during whole-body cooling was unaltered and the response to a cold pressor test was unchanged. The data would indicate that partial acclimatization to cold had been developed. Changes in forearm temperature were correlated with the duration of cold exposure of the hands (P < 0.05) and finger vascular resistance and finger temperature were correlated with responses to cooling before the expedition (P < 0.001 and P < 0.01, respectively). Because the ambient temperature was not clearly lower in Antarctica in comparison to Finland, the reason for the changes developed seems to be the increased exposure to the outdoor climate in Antarctica.

Adult↗
PubMed1993

Gross efficiency of muscular work during step exercise at -15 degrees C and 21 degrees C.

In an effort to assess the effect of ambient temperature on the gross efficiency (Effg) of step exercise 12 subjects performed a modified step test either at -15 degrees C or 21 degrees C ascending to three different heights (corresponding to light, moderate and heavy work), for 20 min each with a frequency of 18 steps min-1. Heart rate (HR), rectal temperature, skin temperatures and heat flux from skin were continuously measured. Oxygen consumption was measured during the last 5 min of each step height and perceptions of thermal sensation were recorded. The results indicate that, while using conventional clothing adequate in these temperatures, Effg is altered in a contradictory manner. At -15 degrees C Effg increased with increasing work load, whereas at 21 degrees C it decreased when the work load increased. The highest Effg (heavy work at -15 degrees C and light work at 21 degrees C) values are reflected as rather similar rectal temperatures. (37.4-37.7 degrees C) and identical mean skin temperatures (32.8 degrees C) as well as the same (slightly warm) thermal sensation of the legs. At -15 degrees C the lowest Effg in light work was probably due to the need to warm up the muscles. At 21 degrees C, on the contrary, the activation of heat dissipation systems was probably responsible for the lowest Effg in heavy work.

Adult↗
PubMed1992

Blood mercury and serum selenium concentrations in reindeer herders in the arctic area of northern Finland.

163 healthy reindeer herders living in the arctic area of northern Finland were investigated for blood mercury and serum selenium concentrations. More than ten percent of the subjects had blood mercury above the upper normal limit. High organic and total organic mercury levels were most common in the northeastern part of the country. High organic and total mercury and selenium values were more common in the Lapps than the Finns. Blood mercury levels increased with increasing fish consumption. The pollution in the northeastern part of this country probably leads to the increased formation of organic mercury, and its enrichment in the food chain. The association of high selenium with high mercury probably reduces the toxicity of the latter.

Analysis of Variance↗
PubMed1992

Rewarming of feet by lower and upper body exercise.

The capacity of different types of exercise to rewarm the body, especially the feet, was studied. Six healthy male subjects wearing winter clothing (2.4 clo, 0.37 degrees C.m2.W-1) were exposed on three occasions to -15 degrees C for 120 min. For the first 60 min the subjects were cooled while sitting motionless and for the latter 60 min they were submitted to cycle ergometer exercise (CE), arm ergometer exercise (AE) or step exercise (ST). The rate of work in CE (about 350 W) served as a reference value for AE and ST. The cooling resulted in an average 1.7 (SEM 0.03) degrees C decrease in mean body temperature (Tb) corresponding to a 425 (SEM 9) kJ heat debt. The ST increased most effectively mean skin, rectal and lower body skin temperatures as well as dry heat loss. The ST increased Tb by 0.83 (SEM 0.16) degrees C, CE by 0.10 (SEM 0.11) degrees C and AE by only 0.07 (SEM 0.12) degrees C. At the end of the exercise the foot temperature was approximately 6 degrees C higher in ST than in CE. The superior rewarming by ST was apparently due to its low mechanical efficiency. Because the increase in Tb could not explain all the changes in foot temperatures, increased circulation and metabolism of the feet would also appear to have been involved.

Adult↗