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Biomedical subjects

H Rintamäki

Publications and source records attributed to H Rintamäki.

At least 19 recordsLinked to original sources
PubMed2001

Outdoor clothing: its relationship to geography, climate, behaviour and cold-related mortality in Europe.

It has been suggested, that the inhabitants of northern European regions, who experience little cold-related mortality, protect themselves outdoors by wearing more clothing, at the same temperature, than people living in southern regions where such mortality is high. Outdoor clothing data were collected in eight regions from 6583 people divided by sex and age group (50-59 and 65-74 years). Across Europe, the total clothing worn (as assessed by dry thermal insulation and numbers of items or layers) increased significantly with cold, wind, less physical activity and longer periods outdoors. Men wore 0.14 clo (1 clo = 0.115 m2 K W-1) more than women and the older people wore 0.05 clo more than the younger group (both P < 0.001). After allowance for these factors, regional differences in insulation and item number were correlated (r = -0.74, P = 0.037; r = -0.74, P = 0.036 respectively), but not those in clothing layers (r = -0.21; P = 0.61), with indices of cold-related mortality. Cold weather most increased the wearing of gloves, scarves and hats. The geographical variation in the wearing of these three together items more closely matched that in cold-related mortality (r = -0.89, P = 0.003). A possible explanation for this may be that they protect the head and hands, where stimulation by cold greatly increases peripheral vasoconstriction causing a rise in blood pressure that procedure haemoconcentration and raised cardiovascular risk.

Aged↗
PubMed2001

Effects of whole body cooling on sensory perception and manual performance in subjects with Raynaud's phenomenon.

Patients with Raynaud's phenomenon (RP) have abnormal digital vasoconstriction in response to cold. The aim of the study was to investigate the effects of cooling on sensory perception and manual performance in healthy male subjects and subjects with RP. There were two groups of subjects with primary RP: 12 subjects fulfilled the criteria of Lewis (L) and the other 12 the more critical criteria of Maricq (M). Control group (C) consisted of 19 healthy men. Subjects were exposed to 5 degrees C for 60 min. Skin temperatures were measured. Finger dexterity, pinch strength, abduction/adduction of fingers, pressure perception threshold and vibration perception threshold were tested during the exposure every 15 min. At the beginning of the exposure the mean (S.E.) finger temperature was 2.5 (1.2) degrees C (P<0.05) lower in M than in C. Manual performance and sensory perception were impaired due to the cooling, the impairment being significantly greater in M than in C. Responses of L were between those of M and C. In a given finger temperature vibration and pressure sensibility and manual performance were lower in M and L than in C. In conclusion, cold exposure decreased sensory perception and manual performance in the subjects with RP to a lower level than in the healthy subjects. Non-thermal factors may also decrease performance in RP.

Adult↗
PubMed2001

Effects of metabolic rate on thermal responses at different air velocities in -10 degrees C.

The effects of exercise intensity on thermoregulatory responses in cold (-10 degrees C) in a 0.2 (still air, NoWi), 1.0 (Wi1), and 5.0 (Wi5) m x s(-1) wind were studied. Eight young and healthy men, preconditioned in thermoneutral (+20 degrees C) environment for 60 min, walked for 60 min on the treadmill at 2.8 km/h with different combinations of wind and exercise intensity. Exercise level was adjusted by changing the inclination of the treadmill between 0 degrees (lower exercise intensity, metabolic rate 124 W x m(-2), LE) and 6 degrees (higher exercise intensity, metabolic rate 195 W x m(-2), HE). Due to exercise increased heat production and circulatory adjustments, the rectal temperature (T(re)), mean skin temperature (Tsk) and mean body temperature (Tb) were significantly higher at the end of HE in comparison to LE in NoWi and Wi1, and T(re) and Tb also in Wi5. Tsk and Tb were significantly decreased by 5.0 m x s(-1) wind in comparison to NoWi and Wi1. The higher exercise intensity was intense enough to diminish peripheral vasoconstriction and consequently the finger skin temperature was significantly higher at the end of HE in comparison to LE in NoWi and Wi1. Mean heat flux from the skin was unaffected by the exercise intensity. At LE oxygen consumption (VO2) was significantly higher in Wi5 than NoWi and Wi1. Heart rate was unaffected by the wind speed. The results suggest that, with studied exercise intensities, produced without changes in walking speed, the metabolic rate is not so important that it should be taken into consideration in the calculation of wind chill index.

Adult↗
PubMed2001

Poor dental status increases acetaldehyde production from ethanol in saliva: a possible link to increased oral cancer risk among heavy drinkers.

Epidemiological data support evidence that poor dental status increases oral cavity cancer risk especially among heavy alcohol consumers, but the causality of this finding is unclear. The enzymatic conversion of ethanol by the physiological oral microflora may lead to an accumulation of the highly carcinogenic intermediate acetaldehyde. This study was conducted to evaluate the role of dental status on the microbial production of acetaldehyde from ethanol in saliva. The microbial acetaldehyde production from ethanol was related to the dental score in 132 volunteers. After adjustment for smoking, alcohol consumption, age and gender, poor dental status was shown to lead to an approximately twofold increase in salivary acetaldehyde production from ethanol (P=0.02). Our results could be an important factor underlying the role of poor dental hygiene and status in oral cancer risk associated with ethanol drinking.

Acetaldehyde↗
PubMed2001

Serum concentrations of collagen degrading enzymes and their inhibitors after downhill running.

In the present study the release of proteins degrading extracellular matrix compounds to circulation was measured after damaging exercise in humans. Muscle damage was induced by downhill running; furthermore, the exercise was performed at both cold temperature (5 degrees C) and room temperature (22 degrees C) to study also the possible effect of environmental temperature on serum concentrations of matrix metalloproteinases MMP-2 and MMP-9, tissue inhibitors of metalloproteinases TIMP-1 and TIMP-2, and MMP-2/TIMP-2 complex, and muscle damage monitored by serum creatine kinase measurements. Results were compared with those obtained from patients having rhabdomyolysis, myositis and Becker muscular dystrophy. The present study demonstrates an acute increase in serum concentrations of MMP-9, TIMP-1, and MMP-2/TIMP-2 complex, but no changes in serum MMP-2 concentrations in response to eccentric exercise. Serum creatine kinase activity data suggest greater muscle damage after downhill running in a cold environment than at room temperature. The present observations about at most slight changes in serum MMP and TIMP concentrations and lack of their correlation to increased serum creatine kinase after exercise indicate that serum measurements of MMPs and TIMPs do not sensitively respond to exercise induced skeletal muscle damage and extracellular matrix regeneration. On the other hand, severe skeletal muscle damage, such as rhabdomyolysis, myositis and Becker muscular dystrophy, seemed to have an effect on serum MMP and TIMP concentrations.

Adult↗
PubMed2001

Blood pressure and endocrine responses of healthy subjects in cold pressor test after acutely increased dietary sodium intake.

The objective of the study was to compare blood pressure and endocrine responses in a cold pressure test in young healthy subjects who had shown increased blood pressure during an acutely increased sodium intake. Subjects (n = 53) added 121 mmol sodium into their normal diet for one week. If the mean arterial pressure had increased by a minimum of 5 mmHg compared to the control measure, they were selected for the experiments. The selected subjects (n = 8) were given 121 mmol supplemental sodium d-1 for 14 days after which they immersed the right hand into a cold (+10 degrees C) water bath for 5 min. The blood pressure increased (P < 0.05) during the test and was independent of the sodium intake. The plasma noradrenaline increased from 2.41 +/- 0.38 nmol l-1 to 2.82 +/- 0.42 nmol l-1 (P < 0.05) with normal diet and from 1.85 +/- 0.29 nmol l-1 to 2.40 +/- 0.37 nmol l-1 (P < 0.05) with high sodium diet. The starting concentrations and the endpoint concentrations were statistically similar. The plasma levels of natriuretic peptides (NT-proANP, ANP and BNP) did not change during the test, and the concentrations were independent of the sodium diet. To conclude, acutely increased sodium intake does not change blood pressure or hormonal responses in a cold pressor test in young healthy subjects.

Adult↗
PubMed2001

Effect of regular winter swimming on the activity of the sympathoadrenal system before and after a single cold water immersion.

This study deals with the adaptation of the sympathoadrenal responses to an acute cold water immersion in ordinary winter swimmers. Hormonal responses were determined at the beginning of the winter swimming period in the autumn and after regular swimming for one and three months. Water temperature in the river was 10 degrees C at the beginning and 4 degrees C after one and three months. The mean duration of the test immersion was 36 s. Plasma catecholamine levels determined before the test immersion decreased with the winter swimming period for one month (NA, p < 0.001, A, p < 0.01). The test immersion significantly increased noradrenaline levels (p < 0.001). Plasma adrenaline and serum cortisol levels were increased or decreased by the immersion. After 1 month's swimming the test immersion to 4 degrees C increased noradrenaline to a similar level than the immersion to 10 degrees C at the beginning. Regularly practiced winter swimming for three months led to diminished catecholamine levels measured immediately after the test immersion (p < 0.01). The results suggest that cold adaptation induced by winter swimming attenuates the catecholamine responses to cold water. Adrenaline responses are also affected by its level prior to the immersion.

Adaptation, Physiological↗
PubMed2000

Blood pressure responses to whole-body cold exposure: effect of carvedilol.

OBJECTIVE: The aim of this study was to test the effects of carvedilol on blood pressure (BP) and heart rate (HR) during whole-body cold exposure in hypertensive and normotensive subjects. METHODS: Ten hypertensive and twelve normotensive subjects were exposed to cold (-15 degrees C, wind 3.5 m/s) three times for 15 min with a 1-week interval between the exposures. The study design was made according to a randomised double-blind, crossover method. Before the cold exposures the subjects ingested carvedilol or placebo once a day (carvedilol 12.5 mg/day for 2 days and then 25 mg/day for 5 days) for 1 week. The systolic (SBP) and diastolic (DBP) blood pressure and HR were measured every 3 min during the test procedures using an indirect ambulatory blood pressure monitor device (ABPM-02, Meditech Co.). RESULTS: In the hypertensive group, the cold exposure increased SBP/DBP from 119/75 mmHg to 143/96 mmHg during carvedilol treatment (P<0.001) and from 132/85 mmHg to 159/106 mmHg during placebo (P<0.001). In the normotensive group the cold exposure increased SBP/DBP from 112/72 mmHg to 142/93 mmHg during carvedilol treatment (P<0.001) and from 121/75 mmHg to 147/98 mmHg during placebo (P<0.001). In the hypertensive group, the levels of SBP, DBP and MAP (mean arterial pressure) were significantly lower with carvedilol than with placebo during the cold exposure although carvedilol did not affect the cold-induced rise of the BP. The BPs were lower also with carvedilol in the normotensive group than the placebo during the cold exposure, but the differences were smaller than in the hypertensive group. Carvedilol decreased the BP more the higher the initial mean SBP/DBP was with placebo during the cold exposure. CONCLUSION: Carvedilol reduced the BP during the cold exposure, especially in the hypertensive subjects but also in normotensive ones, without effect on the cold-induced rise of the BP.

Adrenergic beta-Antagonists↗
PubMed2000

Face temperature and cardiorespiratory responses to wind in thermoneutral and cool subjects exposed to -10 degrees C.

The effects of the thermal state of the body (slightly cool and neutral) and moderate wind speeds on face temperature, blood pressure, respiratory function and pain sensation during cold exposure were studied on eight healthy male subjects. They were dressed in cold-protective clothing and preconditioned at + 20 degrees C (TN) and -5 degrees C (CO) for 60 min, then exposed to -10 degrees C and 0 m x s(-1) (NoW), 1 (W1) and 5 (W5) m x s(-1) wind for 30 min. Thus, each individual was exposed six times. The exposure to wind entailed a combination of strong cooling of the bare face and mild body cooling. The forehead, cheek and nose temperatures decreased during cold exposure, and the decrease was greater at higher air velocities (P < 0.0001). All subjects reported pain sensations at 5 m x s(-1). At the end of exposure only the nose temperature was significantly lower in CO than in TN subjects; it was about 2 degrees C and reached 0 degrees C in two experiments. The systolic and diastolic blood pressure (SBP and DBP, respectively) increased significantly by 7.7 and 5.9 mmHg, respectively, during preconditioning at -5 degrees C, but did not change at + 20 degrees C. SBP and DBP increased during exposure to -10 degrees C in TN by approximately 9 mmHg. However, the total average increase of blood pressure (1-90 min) was similar in TN and CO (SBP 15 mmHg and DBP 13 mmHg). SBP and DBP increased more during exposure to 5 m x s(-1) at -10 degrees C than NoW. Blood pressure responses as observed in this study (SBP and DBP up to 51 and 45 mmHg, respectively) are potential health risks for hypertensive individuals and angina patients. Respiratory functions (FVC, FEV1) were reduced by about 3% by the cold (-5 and -10 degrees C) compared to pre-experiment values. Furthermore, the Wind Chill Index seems to underestimate the cooling power of 5 m x s(-1) at -10 degrees C of bare skin (e.g. face). Therefore it needs to be revised and we suggest that it is expanded to include risk levels for pain sensation.

Adult↗
PubMed2000

Thermal responses to cold wind of thermoneutral and cooled subjects.

The effects of initial thermal state on thermoregulatory responses to cold (-10 degrees C) in a 0.2 (still air), 1.0, and 5.0 m. S(-1) wind speed were studied. Eight young male subjects were first preconditioned in thermoneutral (+20 degrees C, TN) or cool (-5 degrees C, CO) environment for 60 min. After preconditioning the subjects were exposed to wind at -10 degrees C in a standing position, facing the wind, for 30 min. Precooling decreased mean skin temperature (Tsk) by 4.0 (SEM 0.1) degrees C (P < 0.001) and increased heat flux by 57 (SEM 2) W x m(-2) (P < 0.001) in comparison to TN. Cooling rate of Tsk was faster (P < 0.001) in TN than in CO at every wind speed. Even so, Tsk ended up at a lower level in CO (P < 0.001-0.01) than in TN at every wind speed. Local skin temperatures of hand, finger, foot and toe were significantly lower in CO than in TN at the end of all exposures to wind. Heat flux from the skin was 8% higher (NS) in TN at 5.0 m x s(-1) wind speed in comparison to CO. A 5.0 m x s(-1) wind speed increased oxygen consumption significantly (P < 0.001) in both CO and TN in comparison to still air. At 5.0 m x s(-1) wind speed the general thermal sensation was the same (cold) in both TN and CO, despite the higher Tsk in TN. In conclusion, Tsk decreased more rapidly in TN, probably due to rapid skin vasoconstriction and redistribution of circulation to the central body. Probably for the same reason, dry heat loss from the skin was at nearly the same level in both TN and CO. Although the initial thermal state did not affect the amount of heat loss, it significantly affected the peripheral temperatures and thermal sensations and should therefore be taken into consideration in the prediction of thermophysiological responses to wind.

Adult↗
PubMed2000

Thermal effects of emollients on facial skin in the cold.

Ointments are traditionally used in Finland for protection against facial frostbite. Recent epidemiological reports showed unexpectedly, however, that the use of ointments is a statistically considerable risk factor for frostbite of the face and ears. The effects of 4 different emollients on facial temperature were studied in 46 acute cold exposures. The voluntary test persons sat in a cold chamber after emollients were applied thickly on half of the face, while the other half acted as an untreated control. Thermistors and an infrared scanner were used to measure skin temperature of symmetrical areas of the face. The thermal sensations on the corresponding sites were also recorded. Test emollients more often had an objectively cooling than a warming effect on facial skin. However, white petrolatum often produced a subjectively warming skin sensation. "Protective" ointments may cause a false sensation of safety, leading to increased risk of frostbite due to neglect of other protective measures.

Adult↗
PubMed2000

Prediction of duration limited exposure for participants wearing chemical protective clothing in the cold.

The suitability of the IREQ (insulation required) index for predicting the thermal responses of 6 participants wearing chemical protective clothing was tested during exercise at -20 and -25 degrees C. IREQ was used to calculate duration limited exposure (DLE). Measured DLE correlated (r =0.899, p <0.001) with the predicted DLE. In exposures exceeding 40 min, however, the predicted DLE tended to be 10-20 min too short compared to the measured one. During short exposures the prediction was 5-20 min too long. The results show that IREQ overestimated the cold strain in participants wearing chemical protective clothing during cold exposures longer than 40 min. Nevertheless, predicted DLE never exceeded measured times and thus the prediction was always safe from the occupational point of view.

Adult↗
PubMed2000

Increased salivary acetaldehyde levels in heavy drinkers and smokers: a microbiological approach to oral cavity cancer.

The pathogenetic mechanisms behind alcohol-associated carcinogenesis in the upper digestive tract remain unclear, as alcohol is not carcinogenic. However, there is increasing evidence that a major part of the tumour-promoting action of alcohol might be mediated via its first, toxic and carcinogenic metabolite acetaldehyde. Acetaldehyde is produced from ethanol in the epithelia by mucosal alcohol dehydrogenases, but much higher levels derive from microbial oxidation of ethanol by the oral microflora. In this study we investigated factors that might alter the composition and quantities of the oral microflora and, consequently, influence microbial acetaldehyde production. Information about dental health, smoking habits, alcohol consumption and other factors was obtained by a questionnaire from 326 volunteers with varying social backgrounds and health status, e.g. oral cavity malignancy. Paraffin-induced saliva was collected and the microbial production of acetaldehyde from ethanol was measured. Smoking and heavy drinking were the strongest factors increasing microbial acetaldehyde production. Whether poor dental status may alter local acetaldehyde production from ethanol remained unanswered. Bacterial analysis revealed that mainly gram-positive aerobic bacteria and yeasts were associated with higher acetaldehyde production. Increased local microbial salivary acetaldehyde production due to ethanol among smokers and heavy drinkers could be a biological explanation for the observed synergistic carcinogenic action of alcohol and smoking on upper gastrointestinal tract cancer. It offers a new microbiological approach to ethanol-associated carcinogenesis at these anatomic sites.

Acetaldehyde↗
PubMed2000

Stretch- and H-reflexes of the lower leg during whole body cooling and local warming.

BACKGROUND: This study was undertaken to evaluate if possible changes in stretch- and H-reflexes could be related to the changes in the EMG activity of the cooled lower leg muscles observed during a stretch-shortening cycle exercise. METHODS: Eight subjects wearing shorts and jogging shoes were exposed once to 27 degrees C and twice to 10 degrees C for 60 min each. During the second exposure to 10 degrees C, the subject's lower legs were kept warm (10 degrees Clw) with electrical pillows. After the exposures Achilles tendon reflex (stretch reflex) was induced and the EMG activity of the triceps surae was measured. Immediately after reflex measurements the EMG activity of the triceps surae and tibialis anterior during a drop-jump (stretch-shortening cycle) was measured. After similar thermal exposures electrically induced H-reflex from the calf was measured. RESULTS: During the preactivity and stretch phases the EMG activity of the triceps surae increased after the exposure to 10 degrees C, whereas during the shortening phase it decreased. During the shortening phase cooling, on the contrary, increased the activity of tibialis surae anterior. These changes disappeared at 10 degrees Clw. At 10 degrees C the maximum EMG-amplitude of triceps surae during stretch reflex decreased (p<0.05), reflecting suppressed muscle spindle activity. Suppressed spindle activity causes the agonist to be unfacilitated and the antagonist muscle contraction to be uninhibited, which was seen in the present study as decreased agonist and increased antagonist EMG activity during the shortening phase at 10 degrees C. The Hmax/Mmax-ratio, H-reflex latency and amplitude increased at 10 degrees C (p<0.05), reflecting increased motoneuron pool excitability. This in part may explain the increased EMG activity during the preactivity and stretch phases. CONCLUSION: Cooling-induced increase in the excitability of the motoneuron pool and suppression of muscle spindle activity seem to be responsible of the EMG activity changes during the stretch-shortening cycle, consequently decreasing muscular performance.

Adult↗
PubMed2000

Predisposing factors and prevention of frostbite.

This review focuses on the physiological, behavioural and environmental factors which predispose to frostbite. Also prevention of frostbite is summarised. Predisposing factors may increase heat loss, decrease heat production, decrease the insulation of the clothing, make people especially susceptible to cold or make them to behave inadequately. Marked increase in convective or conductive heat loss is often the immediate reason for frostbite. Wind (as described by wind chill index) increases convective heat loss and touching of metal objects increases conductive cooling. Poor insulation of the clothing is also a common reason of frostbite. The insulation can be insufficient when clothing is wet, tight, permeable to wind or does not cover the cold sensitive body parts. Individual factors predisposing to frostbite are inadequate behaviour, low physical fitness, fatigue, dehydration, earlier cold injuries, sickness or poor circulation in peripheral parts of the body. Frostbite is often associated with the use of alcohol. To prevent frostbite, it is necessary to recognise cold risks, practise tasks in the cold, eat and drink well, have physical exercise, have sufficient clothing (also spare clothing), change into dry clothing if necessary and take care of companions. In the cold it is not advisable to get fatigued until exhaustion, sweat excessively, use tight and/or wet clothing, drink alcohol, smoke and expose oneself unnecessarily to wind, metals or fluids.

Adaptation, Physiological↗
PubMed2000

Sequelae of moderate finger frostbite as assessed by subjective sensations, clinical signs, and thermophysiological responses.

The aim of the study was to investigate prevalence and qualities of sequelae following moderate finger frostbite. The study material comprised 30 subjects, who had suffered second-degree frostbite (73% contact frostbite) 4-11 years before this study. In clinical tests 66% of the subjects had an elevated tendency for vasospasm, yet only 20% suffered from white fingers. However, no marked traces of frostbite-related alterations were observed in systemic cardiovascular reflex tests or in X-ray examinations of the frostbite area. Subjective assessments revealed a high prevalence of sequelae (63%), although the primary frostbite was moderate and local. The sequelae in the frostbite area included hypersensitivity to cold (53%), numbness of fingers (40%), and declined sensitivity of touch (33%). Also working ability was lowered due to frostbite sequelae (13%). In cold air provocation tests, the skin temperature of the frostbitten areas decreased more quickly and reached lower values than in healthy control subjects. In conclusion the suffered frostbite was associated with an increased tendency for vasospasm. Subjective sensations of the frostbitten area were associated with thermophysiological changes. The sequelae were reported to worsen in the cold environment thus emphasizing the probable occupational limitations of even moderate cold injury.

Adult↗