Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.10.2 (focal adhesion kinase)
 44,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The role of calcium in initiating smooth muscle contraction is widely accepted. The sources of this calcium are thought to be located both intracellularly and extracellularly. We have recently developed a method by which the cellular localization of calcium in smooth muscle can be determined. This method involves exposing the tissue to 45Ca, rapidly freezing and vacuum dehydrating the tissue, and preparing the tissue for electron microscopic autoradiography (EM ARG). In the present study the distribution of calcium in control and potassium-contracted tissue of the rabbit vas deferens was compared. No significant differences in distribution were observed in the two treatments. This finding provides morphological support for the hypothesis that the calcium used in potassium-induced contraction is primarily of extracellular origin. In addition, significant sequestration by intracellular organelles does not occur during a potassium contraction. In other experiments, the effect of rinsing tissue in cold calcium prior to freezing was investigated. From these data is appears that calcium is removed from the cytoplasmic matrix, plasma membrane, and organelles in a nonuniform manner. Further investigation into these findings should enable us to characterize more precisely the intracellular redistribution of calcium that occurs as a result of a variety of physiological manipulations.
 ...
PMID:The cellular distribution of calcium in freeze-dried rabbit vas deferens using EM autoradiography. 397 81

This study examined both the thermal and metabolic responses of individuals in cool (30 degrees C, n = 9) and cold (18 degrees C, n = 7; 20 degrees C, n = 2) water. Male volunteers were immersed up to the neck for 1 h during both seated rest (R) and leg exercise (LE). In 30 degrees C water, metabolic rate (M) remained unchanged over time during both R (115 W, 60 min) and LE (528 W, 60 min). Mean skin temperature (Tsk) declined (P less than 0.05) over 1 h during R, while Tsk was unchanged during LE. Rectal (Tre) and esophageal (Tes) temperatures decreased (P less than 0.05) during R (delta Tre, -0.5 degrees C; delta Tes, -0.3 degrees C) and increased (P less than 0.05) during LE (delta Tre, 0.4 degrees C; Tsk, 0.4 degrees C). M, Tsk, Tre, and Tes were higher (P less than 0.05) during LE compared with R. In cool water, all regional heat flows (leg, chest, and arm) were generally greater (P less than 0.05) during LE than R. In cold water, M increased (P less than 0.05) over 1 h during R but remained unchanged during LE. Tre decreased (P less than 0.05) during R (delta Tre, -0.8 degrees C) but was unchanged during LE. Tes declined (P less than 0.05) during R (delta Tes, -0.4 degrees C) but increased (P less than 0.05) during LE (delta Tes, 0.2 degrees C). M, Tre, and Tes were higher (P less than 0.05), whereas Tsk was not different during LE compared with R at 60 min.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Comparison of thermal responses between rest and leg exercise in water. 403 May 69

In 10 women, external cold and heat exposures were performed both in the middle of luteal phase (L) and in the early follicular phase (F) of the menstrual cycle. Serum progesterone concentrations in L and F averaged 46.0 and 0.9 nmol X l-1, respectively. The experiments took place between 3:00 and 4:30 A.M., when the L-F core temperature difference is maximal. At neutral ambient temperature, esophageal (Tes), tympanic (Tty), rectal (Tre), and mean skin (Tsk) temperatures averaged 0.59 degrees C higher in L than in F. The thresholds for shivering, chest sweating, and cutaneous vasodilation (heat clearance technique) at the thumb and forearm were increased in L by an average of 0.47 degrees C, related to mean body temperature [Tb(es) = 0.87Tes + 0.13 Tsk] and to Tes, Tty, Tre, or Tsk. The above-threshold chest sweat rate and cutaneous heat clearances at the thumb and forearm were also enhanced in L, when related to Tb(es) or time. The metabolic rate, arm blood flow, and heart rate at thermoneutral conditions were increased in L by 5.0%, 1.1 ml X 100 ml-1 X min-1, and 4.6 beats X min-1, respectively. The concomitant increase in threshold temperatures for all autonomic thermoregulatory responses in L supports the concept of a resetting of the set point underlying the basal body temperature elevation in L. The effects of the increased threshold temperatures are counteracted by enhanced heat loss responses.
 ...
PMID:Influence of menstrual cycle on shivering, skin blood flow, and sweating responses measured at night. 407 97

This study examined the effect of acute cold exposure on coagulation (PTT) and fibrinolysis (ELT), and the effect of cooling on subsequent exercise-induced coagulation and fibrinolytic responses. Ten male volunteers were tested at 5 degrees C and 28 degrees C on alternate days. Each subject began by sitting quietly for 60 min. Each then exercised on a cycle ergometer at 50 W for 5 min followed by 150 W for 10 min. Venous blood samples were taken before rest, after rest, and after exercise for each temperature on each of the two days. PTT, ELT, and hematocrit (HCT) were determined at each interval. Rectal temperature (Tre) and mean skin temperature (Tsk) were assessed at 15-min intervals throughout. Tsk was stable under neutral conditions but declined rapidly in the cold environment. Tre response was more complex but was significantly different for one contrast only (CE less than NE). ELT was shortened to 74, 62, and 44% while HCT increased to 107, 107, and 111% of pretest values for CR, NE, and CE, respectively. No significant change was noted for PTT. It is concluded that acute cold exposure as well as exercise stress results in an increase in ELT activity of blood; simultaneous enhancement of the coagulation status of the blood in response to stress is not inextricably linked to an elevation of fibrinolytic activity, a result that questions the importance of the Hageman factor dependent pathway between coagulation and fibrinolysis.
 ...
PMID:Coagulation and fibrinolytic responses to exercise and cold exposure. 673 80

A conflict was contrived between thermal and non-thermal drives in humans to study the effects of varying degrees of voluntary suppression of behavioral temperature regulation. Five, young, near-nude males were paid 2, 5, 10, 20 or 40 cents per min to expose themselves to increasing cold (15 degrees to 0 degree C in 2 hours), after being instructed to terminate the exposure as soon as the cold discomfort exceeded the monetary reward. The duration of voluntary cold exposure was approximately linearly related to the logarithm of monetary reward. Reported cold discomfort was greater with high than with low rates of reward. Although V02 approached summit metabolism, the capacity for shivering did not appear to limit cold tolerance. Subjects adopted various strategies for coping with the conflict but, in general, greatest cold tolerance was recorded in subjects of large body mass and willing to tolerate low Tsk.
 ...
PMID:Human thermoregulatory behavior during a conflict between cold discomfort and money. 683 37

The effect of cold exposure on the sympathoadrenal system in primates was studied with and without ketamine anesthesia in eight adult rhesus monkeys. Each monkey was placed in a primate chair at a thermoneutral temperature (25 degrees C) for 1 h (control) followed by cold exposure (12 degrees C) for 3 h or placed in a circulating water bath (28 degrees C) to induce a decrease in core temperature (Tre) to 35 and 33 degrees C. Plasma catecholamines were analyzed by high-pressure liquid chromatography with electrochemical detection (60-65% recovery, coefficient of variation = 15%). The 3-h cold exposure was associated with a 175% increase above control levels of norepinephrine (NE) and a 100% increase in epinephrine (E). Decreases were evident in Tre (0.5 degree C), mean skin temperature (Tsk, 5.5 degrees C), and mean body temperature (Tb, 2.0 degrees C). Continuous infusion of ketamine (0.65 mg . kg-1 . min-1) resulted in no change in the plasma levels of NE and E from the control levels. Tre, Tsk, and Tb all showed greater declines with the addition of ketamine infusion to the cold exposure. Water exposure (28 degrees C) under ketamine anesthesia resulted in a drop in Tre to 33 degrees C within 1 h. Plasma levels of NE and E were unchanged from control values at Tre of 35 and 33 degrees C. The data suggest that the administration of ketamine abolished both the thermoregulatory response and the catecholamine response to acute cold exposure.
 ...
PMID:Sympathoadrenal responses to cold and ketamine anesthesia in the rhesus monkey. 685 96

The thermal and metabolic responses to exercise were studied in a cold environment with and without a wind. Six men and two women rode a cycle ergometer for 90 min at 55-60% VO2max in a -20 degrees C environment. Subjects were exposed to a 4.1 m . s-1 wind on two of the four exposures. The subjects wore regulation cross-country ski uniforms. An additional vest was worn on 2 d, 1 d with the wind and 1 d without the wind. Total insulation for the ski uniform (Icl+a) was 1.59 clo and 1.77 clo with the vest. Final Tre, Tsk, and Tb were significantly lower, and radiative and convective heat loss, heat loss from body storage, and tissue insulation (It) were significantly greater when exercising in the wind. The addition of the vest increased only Tsk. Both metabolic rate and heart rate increased significantly during exercise, but no significant differences were observed between wind and no-wind conditions. The subjects responded to the increased cooling effect of the wind by increasing It, however, this response was not sufficient to prevent loss of stored heat and Tre from falling. It was concluded that the exercise intensity must be 10 METS or greater to maintain thermal balance when exercising in a -20 degrees C environment with a 4.1 m . s-1 wind if Icl+a = 1.59 clo.
 ...
PMID:Effects of wind on the thermal and metabolic responses to exercise in the cold. 707 Feb 56

Sublingual temperature (Tor), average skin temperature (Tsk), and skin heat flow (Hsk) were determined in a field study for six Greek sponge divers and seven nondiving controls during head-out immersions at water temperature of 21 degrees C. Wetsuits kept Tsk at 22-28 degrees C for 1-3 h until Tor fell to 36.5-35.5 degrees C and violent shivering [metabolic rate (M) = 100-150 W . m-2] ended the test. At a steady Tsk, immediately before shivering, overall tissue insulation (It), calculated as (Tor--Tsk)/Hsk, was linearly related to mean subcutaneous fat thickness (MFT) in both groups without statistical difference between them. The onset of shivering, as detected by a sharp increase of M, occurred at the same Tor for a Tsk of about 26 degrees C, and the relationship of M vs. Tor (i.e., metabolic sensitivity) was the same for both groups. Contrary to other groups accustomed to diving in cold water, the use of a wetsuit for a long time has evidently prevented cold adaptation in these divers.
 ...
PMID:Thermal insulation and shivering threshold in Greek sponge divers. 708 18

The effects of altering skin and core temperature by cold exposure and exercise on substrate mobilization and utilization were examined. Six subjects between the ages of 22-27 years rested and exercised in neutral and cold environments to produce 1) a neutral core and neutral skin temperature, 2) a neutral core and cold skin temperature, and 3) a cold core and cold skin temperature. Free fatty acid (FFA), glucose (GL), Lactate (LA), hemoglobin (Hb), and hematocrit (Hct) concentrations were measured along with heart rate (HR), respiratory exchange ratio (R) and oxygen consumption (VO2) after 30, 60, and 90 min of exposure to each condition. FFA, GL, LA, Hb, and Hct concentrations increased significantly during rest when both mean skin temperature (Tsk) and rectal temperature (Tre) were reduced. Plasma FFA concentration was also significantly elevated and R values were reduced during exercise when both Tsk and Tre were lowered compared to exercise in a neutral environment. No significant differences in substrate concentration, hemoconcentration, or R values were observed when Tsk alone was reduced at rest or during exercise. It is concluded that a preferential utilization of fat occurs during exercise in the cold when both Tsk and Tre are reduced compared to exercise in a neutral environment.
 ...
PMID:The effects of rest and exercise in the cold on substrate mobilization and utilization. 715 40

The study was conducted on 20 high-altitude natives (HAN-I) 19-32 years old, to evaluate the changes in autonomic responses during their 2-months sojourn on the plains, and on return to high altitude (HA). The autonomic indices measured were heart rate HR), blood pressure (BP), oral temperature (Tor), mean skin temperature (Tsk), respiratory rate (RR), Cold pressor response (CPR), HR-response to tilt at 70 degree, and alpha index (AI) of EEG (occipital). These indices were recorded periodically during the 2 months of their stay on the plains, and thereafter on return to altitude for a period of 1 month. For comparison, the same responses were studied on 10 lowlanders (LL) on the plains and on induction to HA along with HAN-I. The study was repeated at altitude, once on 10 HAN who had never been to the plains (HAN-II) and on 10 acclimatised lowlanders. The results suggest that the relative parasympathetic dominance observed in natives at HA showed a gradual decrease during their sojourn on the plains, probably due to the elevation in sympathetic activity. On return to high altitude, they showed further increase in sympathetic excitation, as observed in LL on acute induction, but the magnitude of this response was less in natives. However, they showed a trend to faster return of autonomic responses to their initial level compared to LL.
 ...
PMID:Autonomic responses of high-altitude natives during sojourn at plains and on return to altitude. 725 93


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>