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At least 865 records · Page 48Linked to original sources
PubMed1999

Dynamic force responses in electrically stimulated triceps surae muscles: effects of fatigue and temperature.

To elicit dynamic force responses (unfused tetani) in isometric triceps surae muscles, low frequency electrical stimulation ranging from 12.5 to 30.0 Hz was applied. The fusing frequency (FF) and the relative dynamic force amplitude (DF) at the 20% and 40% maximum voluntary contraction (MVC) levels were calculated as parameters to determine effects of muscle fatigue (n = 6) and local muscle cooling. In the fatigued muscle (15 min plantar flexion at a 20% MVC level), the FF and DF increased when the fatigue was induced by voluntary contraction (FF increased from 19.6 to 22.5 Hz at 20% MVC) and also when induced by electrical stimulation (FF increased from 19.2 to 23.3 Hz). Cooling of the muscles showed an inverse effect on both parameters, indicating contractile slowing. The responsible physiological mechanisms as well as practical applications, using low frequency stimulation to monitor degenerative changes in muscles, are discussed.

Adult↗
PubMed2005

[A patient who for one year shared his apartment with his dead lady-friend's corpse].

A 58-year old unemployed painter had for one year shared his apartment with his lady-friend's corpse and not talked to anyone about her death. When admitted to our hospital, loss of drive, initiative, interest, psychomotor activity and emotional response as well as poverty of speech were the main clinical features. Not having been able to care for his own vital needs such as food, shelter and protection against cold temperature, he was neglected and suffered from frost-bites. We diagnosed a schizophrenia simplex and initiated neuroleptic treatment using olanzapine. During the course of treatment there was some improvement regarding affect and psychomotor activity, his loss of drive and initiative and indifference regarding his own situation in life did hardly improve.

Antipsychotic Agents↗
PubMed2006

Heat strain and gross efficiency during endurance exercise after lower, upper, or whole body precooling in the heat.

The maximal power that muscles can generate is reduced at low muscle temperatures. However, in prolonged heavy exercise in the heat, a high core temperature may be the factor limiting performance. Precooling has been shown to delay the attainment of hyperthermia. It is still unclear if the whole body should be cooled or if the active muscles should be excluded from cooling in order to maintain muscle power. An experiment was performed to compare thermal strain and gross efficiency following whole body or partial body cooling. Eight well-trained participants performed 40 min of 60% VO2max cycling exercise in a 30 degrees C, 70% relative humidity climatic chamber after four different precooling sessions in a water perfused suit: N (no precooling), CC (45 min whole body precooling), WC (45 min lower body precooling), and CW (45 min upper body precooling). The uncooled body part was warmed in such a way that the core temperature did not differ from that in session N. Gross efficiency was used to compare performance between the sessions since it indicates how much oxygen is needed for a certain external load. The gross efficiency did not differ significantly between the sessions. Differences in heat loss and heat storage were observed during the first 20 min of exercise. The evaporative heat loss in session WC (305 +/- 67 W) and CW (284 +/- 68 W) differed from session N (398 +/- 77 W) and CC (209 +/- 58 W). More heat was stored in session CC (442 +/- 125 W) than in sessions WC (316 +/- 39 W), CW (307 +/- 63 W), and N (221 +/- 65 W). It was confirmed that precooling reduces heat strain during exercise in the heat. No differences in heat strain and gross efficiency were observed between precooling of the body part with the exercising muscles and precooling of the tissues elsewhere in the body.

Adolescent↗
PubMed1983

Coronary rheothermia: a quasi non-invasive method for controlling bypass patency.

A method based on the principle of thermodilution was developed for a quasi non-invasive permeability control of aortocoronary bypass. An epivascularly-attached thermistor records the cooling of the bypass wall when, following the intravenous injection of 5 to 10 ml of a NaCl solution at 4 degrees C, a bolus of cooled blood passes through the bypass. During cardiosurgical intervention, the thermistor is attached to the venous bridge by one or 2 sutures. The efferent cable goes through the thorax wall and is coupled to a subcutaneously implanted telemetric amplifier unit. The influence of the vessel wall on the perivascular temperature signal, as compared to the intravascular one, was studied in acute and chronic animal experiments. In acute experiments the perivascular peak of temperature was found to be lower than the intravascular one. Continuous measurements over 9 days showed variations in the perivascular signals which must have been due to changes in the thermal capacity of the tissue coupled to the thermistor as well as to changes in resistance caused by a variable extent of scarred area and by the varying water content of the wound bed. These variables will continue to keep rheothermia within the limitations of a method with primarily binary results (= bypass: open or closed). Given stable coupling conditions after full development of the scar around the thermistor, the signal falsification by the then constantly coupled tissue capacity becomes calculable such as to obtain semiquantitative results which, theoretically should vary predominantly with cardiac output.

Animals↗
PubMed2003

Seasonal reproduction and delayed sexual maturity in mound-building mice Mus spicilegus.

In the mound-building mouse, Mus spicilegus, which is found from Central to Eastern Europe, reproduction is seasonal and limited to spring and summer. In autumn, the mice build voluminous mounds composed of vegetable matter covered with earth, where juvenile animals (autumnal individuals) over-winter in groups without reproducing. Autumnal animals delay reproduction until the next spring when they are 6 months old. The influence and interactions of environmental (short light period and cold temperature (C conditions) compared with long light period and temperate temperature (T conditions)) and social factors (lack of odours from breeding adults (NB conditions) compared with presence of odours from breeding adults (B conditions)) on reproduction and sexual maturation were studied. Forty groups of three autumnal individuals (two males and a female or two females and a male) were placed in four experimental conditions (CB, CNB, TB and TNB), corresponding to interactions between environmental and social factors (n = 10 groups for each condition). Of the 40 groups only one initiated reproduction during the 18 weeks of cohabitation. Subsequently, animals were separated and isolated for 1 month and then paired with unfamiliar partners. Reproduction was monitored for an additional month, and 24 out of 39 females reproduced. In addition, of eight reproducing pairs placed in C conditions and 10 reproducing pairs maintained in T conditions, all but one pair continued reproduction. It was concluded that the delay in reproduction observed in autumnal individuals was the result of the social effects of living in groups as opposed to the environmental conditions of winter.

Animals↗
PubMed2004

FRIGIDA-related genes are required for the winter-annual habit in Arabidopsis.

In temperate climates, the prolonged cold temperature of winter serves as a seasonal landmark for winter-annual and biennial plants. In these plants, flowering is blocked before winter. In Arabidopsis thaliana, natural variation in the FRIGIDA (FRI) gene is a major determinate of the rapid-cycling vs. winter-annual flowering habits. In winter-annual accessions of Arabidopsis, FRI activity blocks flowering through the up-regulation of the floral inhibitor FLOWERING LOCUS C (FLC). Most rapid-flowering accessions, in contrast, contain null alleles of FRI. By performing a mutant screen in a winter-annual strain, we have identified a locus, FRIGIDA LIKE 1 (FRL1), that is specifically required for the up-regulation of FLC by FRI. Cloning of FRL1 revealed a gene with a predicted protein sequence that is 23% identical to FRI. Despite sequence similarity, FRI and FRL1 do not have redundant functions. FRI and FRL1 belong to a seven-member gene family in Arabidopsis, and FRI, FRL1, and at least one additional family member, FRIGIDA LIKE 2 (FRL2), are in a clade of this family that is required for the winter-annual habit in Arabidopsis.

Amino Acid Sequence↗
PubMed1993

Peroxisome biogenesis in the yeast Hansenula polymorpha is controlled by a complex set of interacting gene products.

We have studied the genetic interactions between mutant alleles in 12 genes, designated PER1-PER12, which are essential for peroxisome biogenesis in the yeast Hansenula polymorpha. Recessive mutations in any of these genes determined three different morphological phenotypes: (i) complete absence of peroxisomes (Per-); (ii) presence of small peroxisomes in conjunction with a major fraction of peroxisomal matrix proteins in the cytosol (Pim-); and (iii) presence of peroxisomes with aberrant crystalline matrix substructure (Pss-). Extensive complementation analysis showed many cases of noncomplementation--that is, diploids that contained both wild-type and mutant alleles of two different PER genes were unable to grow on methanol and showed peroxisomal defects. The observed cases of unlinked noncomplementation appeared to be gene and allele specific and were predominantly observed at lower temperatures (cold sensitive). The genetic results obtained were used to formulate a model of PER gene product interactions. In this model, five PER gene products are key or core components of the complex. Other PER gene products appear to play a more peripheral role.

Alleles↗
PubMed1984

Effects of cooling in infant rats on growth, maturation, sleep patterns and responses to food deprivation.

The confounding effects of undernourishment and body cooling, resulting from maternal separation, were investigated by separating food and warmth deprivation. Rat pups aged 3-16 d were deprived of food for alternate 24-h periods by removal from the lactating mother. Some of the pups were placed with a foster mother, who kept them warm, whereas others were put in an empty cage at 22 degrees which resulted in a sharp drop in body temperature. Pups which were kept warm showed great fluctuations in weight between periods of starvation and feeding. The cooled pups lost less weight during deprivation but also recovered less on refeeding. The resultant growth rate was much lower in non-fostered (i.e. cooled) than in fostered pups. Up to the age of 8 d, cooled pups failed to raise their body temperature above that of the surroundings and did not digest the milk in their stomachs. Although, thereafter, they were able to raise their temperature to 26 degrees and to digest stomach contents, the extra energy expended resulted in more severe growth restriction. One-third of the pups died at 16 d but the rest were quickly rehabilitated by ad lib. feeding and showed a normal growth rate, although they remained smaller than the controls. The development of nipples, hair, eye opening and vaginal opening was related more to chronological age than to weight. A side effect of cooling was an almost complete abolition of active (REM) sleep, which is normally very high in infants; a slight rebound increase in active sleep was seen at 21 d. Direct as well as side effects of cooling may thus be responsible for some of the observed consequences of maternal separation.

Animals↗
PubMedDate not supplied

Effects of a novel ice-cooling technique on work in protective clothing at 28 degrees C, 23 degrees C, and 18 degrees C WBGTs.

This study tested a new ice cooling system that permits ice cooling system recharge without personal protective clothing removal. Six male volunteers (22.1 +/- 1.2 years) underwent tests with the new ice cooling system (COOL) and without (NOCL) at a moderate work rate (450 W) in three environments of 28, 23, and 18 +/- 1 degrees C wet bulb globe temperature. Walks at 28 degrees C were carried out first with NOCL and COOL counterbalanced, then test order and environment were counterbalanced. At 28 degrees C, mean work time in COOL significantly increased by 37.5 min (188%) over NOCL (p < 0.05). At 23 degrees C mean work time in COOL was significantly increased by 44.3 min (171%) compared with NOCL (p < 0.05). Mean work times at 18 degrees C were not significantly different, although all subjects completed the 120 minutes of work in COOL compared with a mean work time of 109 +/- 20 min for NOCL. During rest, mean reductions in rectal temperature were significantly greater in COOL than NOCL (p < 0.05) at 28 and 23 degrees C. Mean heart rate calculated for the same point in both treatments was significantly lower for COOL at 28, 23, and 18 degrees C (p < 0.05). Thermal comfort rating was significantly different at 18 and 23 degrees C (p < 0.05). This new design seemed to provide comparable cooling to conventional vests and also provides greater practicality for field use. Even in experimental form the suit demonstrated increased productivity due to extended tolerance time.

Adult↗
PubMed1967

On chilling.

Explore the source record for details and available documents.

Body Temperature↗
PubMed1998

Efficacy of a water-cooled garment for auxiliary body cooling in heat.

The efficacy of a water-cooled jacket for auxiliary body cooling was examined under a simulated hot environment. The personal garment comprised of a water re-circulating three-layered vest of cotton fabric lined with 2 mm diameter latex tubing and inter-spaced coating of rubberized solution. Four subjects wearing the water-cooled jacket were tested in the environment chamber (30, 35 and 40 degrees C DB, 50-60% RH, air velocity 0.3, 0.6 and 0.9 m/s, with corresponding average effective temperature of 26 +/- 2.3, 33 +/- 1.1 and 36 +/- 1.5 degrees C). The inlet water temperature was maintained at 10-12 degrees C, with flow rates of 2.6 +/- 0.3, 4.3 +/- 0.3 and 5.1 +/- 0.3 l/h). At 30 degrees C DB, variation in water flow had marginal effect on microclimate, while at higher temperatures (35 and 40 degrees C DB), the re-circulating cooled water had noticeable effects in lowering microclimate, trunk and other skin temperatures, and maintaining the body core within 36.7 +/- 0.2 to 37.5 +/- 0.2 degrees C, over 2 h exposure at 35 and 40 degrees C DB. The observation indicates that the water-cooled jacket provided auxiliary cooling to maintain comfortable microclimate, skin and body core temperatures. This enabled subjects to sustain comfortable heat balance over 2 h heat exposure without any noticeable heat strain.

Adult↗
PubMed1994

Mycotic disease in the common New Zealand gecko (Hoplodactylus maculatus).

Two adult female geckoes (Hoplodactylus maculatus) from the National Wildlife Centre, Mt Bruce, Masterton, died within the period of a month and were presented to the Department of Veterinary Pathology and Public Health at Massey University for necropsy. The first gecko had numerous 1-2 mm diameter punctate ulcers of the skin over the ventral and dorsal regions of the body. The second animal had slight discolouration of some of the scales. Skin swabs were taken from each case for culture. There were no other gross lesions apparent at necropsy. Histologically, the only lesions in the first gecko were areas of epidermal and dermal ulceration involving fungi and bacteria. In the second gecko, there was limited inflammation in the skin, but in the lungs there was necrosis of the pulmonary septae and constituent muscle bundles caused by fungi whose septate mycelia extended into adjacent large blood vessels and caused mycotic thrombi; hyphae were also found in the spleen and liver. Paecilomyces sp. septate fungus was recovered from both geckoes and Pseudomonas spp. and a mixed Gram-negative flora were recovered from the cutaneous lesions on culture. The death of the first gecko was considered to be due to widespread ulcerative dermatitis, while that of the second gecko was thought to be due to mycotic pneumonitis and mycotic septicaemia. It is believed that environmental factors, such as cold temperature and high humidity, contributed to a reduction in the immune response in the affected geckoes, with the consequent development of overwhelming fungal infections.

Journal Article↗
PubMedDate not supplied

Exposure hypothermia and the winter sports SCI participant.

Sensation is impaired in the individual with a complete spinal cord injury and it can be compromised in those with incomplete lesions. Quadriplegics and high paraplegics are, therefore, susceptible to environmental temperature changes (partially poikilothermics). Physicians have assumed that SCI persons engaged in winter sports activities are sensitive to exposure hypothermia. To test this premise, participants were examined within five minutes following their arrival from the ski slopes. Sublingual temperature, pulse and respirations were obtained from nine participants. Exposure hypothermia was found in one-third of the selected individuals. We concluded that exposure hypothermia is one of the complications to look for in the winter sports SCI participant, and that cases could be misdiagnosed if physiological knowledge of the SCI person is lacking.

Adult↗
PubMedDate not supplied

Increasing the systemic temperature during regional hyperthermia: effect of a cooling strategy on tumour temperatures and side-effects.

In the application of regional hyperthermia, optimization of the temperature distribution remains necessary. One of the tools that might be used is a modest increase in the systemic temperature to diminish cooling by blood perfusion. This study investigates (1) if it is feasible to increase the systemic temperature by applying other cooling strategies, without inducing unacceptable systemic stress, and (2) whether a rise in systemic temperature results in improvement of tumour temperatures. Eleven patients with locally advanced cervical carcinoma and 12 patients with locally advanced prostate carcinoma were treated with our Coaxial TEM regional hyperthermia system. In this system, the temperature of the open water bolus can be easily adjusted. Two cooling methods were applied alternately, one with a relatively low water temperature (method A), the other with a higher water bolus temperature in combination with extensive head/chest cooling by a hand shower (method B). Method B resulted in significantly higher systemic temperatures, for both patient groups separately (0.8, respectively, 0.5 degrees C) and for the total patient group (0.7 degrees C). Additionally, all tumour index temperatures were higher. For the combined group (for T50: 0.4 degrees C) and for the cervix group (for T50: 0.7 degrees C), it reached statistical significance. The raise in core temperature led to a significantly higher increase in heart rate. For the group of cervix patients, higher systemic temperatures resulted in more treatment-limiting systemic stress. For the prostate patients, systemic stress was not an important issue. Since the raise in systemic temperature did not influence the overall tolerance of treatment, method B could be applied to this group. However, the increases in tumour temperatures were small, and potential hazards of systemic temperature increase should be considered.

Adult↗