Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0009443 (cold)
 92,137 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of d-amphetamine-induced hypothermia among rats maintained at a cold ambient temperature is related to its ability to release dopamine in the dopaminergic neurons in the mesolimbic pathway. However, the physiological mechanisms which mediate the hypothermia (heat loss or a decrease in heat production) are not known. Since we have failed to demonstrate effects induced by d-amphetamine on food intake or on heat sensors on the rat's tail we conclude that these are not the mechanisms involved in hypothermia. Effects of d-amphetamine on O2 consumption and CO2 production of rats kept at various ambient temperatures were investigated in order to find out if there is any relation between a decrease in body temperature and a decrease in the Basal Metabolic Rate. Neither such relations nor any relations between levels of body temperatures and levels of motor activity were found. The problem of the peripheral mechanisms involved in d-amphetamine-induced hypothermia remain as yet unidentified.
 ...
PMID:D-Amphetamine thermal effects, metabolic rate and motor activity in rats. 59 Nov 93

In order to know the mode of action of norepinephrine in enhanced utilization of plasma free fatty acids (FFA) in cold acclimation, albumin-bound 14C-palmitate was infused intravenously at a constant rate into cold- and warm-acclimated rats under pentobarbital anesthesia with and without norepinephrine infusion. Rectal temperature, CO2 output and plasma FFA, from which the rates of FFA uptake and oxidation were calculated, were determined simultaneously. Similar fractions, that is, 7 and 5% of the total uptake of plasma FFA by the tissue were immediately oxidized in both cold- and warm-acclimated rats, respectively. Norepinephrine infusion caused a significant increase in all the parameters examined. In addition, during hormone infusion the percentage of FFA uptake oxidized was elevated from 22% in control to 50% in cold-acclimated rats. This increment was accompanied with greater increases in rectal temperature and CO2 output. Similarly, in functionally eviscerated cold-acclimated rats, norepinephrine induced a greater increase in the percentage of FFA uptake oxidized than in eviscerated controls. These results indicate that although the FFA uptake was increased simultaneously norepinephrine infusion casued a more marked acceleration of the oxidation of plasma FFA in the cold-acclimated rats than in control rats.
 ...
PMID:Effects of norepinephrine on uptake and oxidation of plasma free fatty acids in cold-acclimated rats. 60 88

The metabolism of cold and 14C-[U]-glutamine in isolated kidney tubules of normal rats was studied in vitro to establish the relative importance of glucose synthesis and complete oxidation to CO2 for the metabolism of this amino acid in vitro. These metabolic fates were estimated by drawing a complete balance of the nitrogens and of the carbon chains of the extracted glutamine and studying the formation of 14CO2 from 14C-glutamine. It was found that glucose production constitutes the major fate for glutamine metabolism with 1 mM glutamine and that glutamine oxidation constitutes less than 20% of the metabolic fate of the carbon skeleton of this amino acid. With 5 or 10 mM glutamine however, the maximal oxidation to CO2 becomes more important (25%).
 ...
PMID:The role of oxidation in the renal metabolism of glutamine by rat kidney tubules in vitro. 61 58

Nowadays, domiciliary long-term O2 therapy is given to certain patients with chronic arterial hypoxemia (PaO2 less than 55 mm Hg). However, it is important to exclude cases with severe CO2 retention (PaCO2 greater than 55 mm Hg). Hypoxemic and only slightly hypercapnic patients chiefly suffer from COLD and sometimes from a severe restrictive ventilatory disorder such as chronic bilateral pleural effusions or advanced kyphoscoliosis. The most important precondition for long-term O2 therapy is correct adjustment of all other procedures of pulmonary treatment, as well as total abstention from smoking. Common sources for domiciliary O2 therapy are bottles delivered to the patient's home weekly by the O2-producing firm. A new machine which appears to offer for greater facilities is the O2 concentrator of Rimer-Birlec (Cardiff, Wales). 2 liters O2/min are given via a naso-pharyngeal tube for 15 h per day. Without O2 during 9 h per day, the patient is able to follow appropriate employment. In domiciliary long-term O2 therapy the cost of O2 supply by the O2 concentrator is half that of bottles delivered to the home weekly. The new O2 concentrator for domiciliary long-term O2 therapy is recommended as by far the most economical source of O2. Other sources of O2 such as liquid O2 or chemically produced O2 are uneconomical for domiciliary use. Only hospitals will benefit from supplying their pipelines from a container with liquid oxygen instead of using gaseous O2 from bottles. The cost of the former is 3/4 that of the latter.
 ...
PMID:[Indications and costs of long-term oxygen therapy]. 62 39

A study was performed to examine microclimate in 14 stables belonging to 10 horsemen's teams and clubs; five of these houses were new-built. In five race-horse stables housing 16 horses each, on an average, where the optimum air temperature ranged from 10 degrees C to 12 degrees C, measurements and examinations were performed in the winter period and the following results were obtained: space per 1 horse housed 42.9 plus or minus 8.7 m-3, relative air humidity 74.3 plus or minus 3.8%, CO2 concentration 0.175 plus or minus 0.027%, NH3 concentration 0.00135 plus or minus 0.00044%. A large majority of horse stables under our conditions lack suitable ventilating equipment for winter and for cold periods. Together with the present-day building technology and with excessive space of box-type houses, this implies that microclimate conditions are unsuitable and harmful to health; in particular, this is true of cold and wet conditions. In the existing stables this problem can be solved by additional heating, preferably with the hot-air system. It is necessary that horse stables should have good thermal-insulation characteristics, with plastered brick walls 45 cm in thickness and with thermally insulated loft. Floors must be solid, hard, and plane. Modern building technology and new materials must secure all the required parameters, with due respect to all factors constituting microclimate and to purposeful layout of race horse stables. It appears desirable to issue a state standard for the construction of horse stables.
 ...
PMID:[Various indices of microclimate in the newly built and re-adapted stables for race horses]. 80 17

Unanaesthetized guinea-pigs, unadapted to cold, were used to study the effect of 20--30 min hypoxaemic hypoxia on the thermoregulatory responses to a moderately low ambient temperature. Hypoxia was produced by intravenous infusion of gaseous CO2. The rate of CO2 administration was adjusted to obtain oxygen uptake equivalent to 70% of the value found at neutral temperature. It was found that at 28 degrees C neither the internal nor the surface temperature changed significantly during hypoxia and oxygen uptake returned to its initial value 15--20 min after cessation of CO2 infusion. At 15 degreesC both the internal and surface temperature as well as oxygen uptake were reduced during hypoxia and they did not return to the initial level 60 min after cessation of CO2 infusion. The temperatures measur-d and oxygen uptake decreased further after each succesive period of CO2 infusion.
 ...
PMID:The effect of environmental temperature on thermoregulatory disturbances caused by hypoxaemic hypoxia in the guinea pig. 89 14

Spontaneously contracting myocytes were isolated from ventricles of the adult rat heart. Hearts were perfused retrogradally via the aorta for 30 minutes at 37 degrees C with Ca2+-free phosphate-buffered saline containing collagenase and hyaluronidase. The venticles were divided into pieces and incubated 15 minutes with the enzymes. Dislodged cells were decanted, diluted with cold buffer and allowed to settle. The washed cells were then sedimented through 3% Ficoll. This procedure yielded approximately 50 mg of protein from 1 gm of heart. Viability measured by trypan-glue exclusion is 90-95%. Approximately 80% of the cells were beating. Scanning electron microscopic studies suggest that the isolated myocytes are morphologically intact. The cells oxidize glucose, pyruvate, citrate and palmitate to CO2 and synthesize protein and RNA. Uptake of glucose, 2-deoxyglucose, leucine and taurine was saturable. Glucose uptake was stimulated by insulin. The cells retained LDH and CPK as well as their capacity to oxidize substrates after 24 hours at 4 degrees C or 4 hours at 37 degrees C. After 24 hours at 4 degrees C the cells resume contracting when returned to room temperature. The procedure reported here for the isolation of spontaneously contracting, adult, rat heart myocytes provides cells with a high index of viability and greater yield than previously reported methods. The cells retain metabolic activity and withstand storage for longer periods than other described preparations.
 ...
PMID:Isolation and characterization of myocytes from the adult rat heart. 91 20

Synthesis of chlorophyll always preceded the synthesis of solanine in cold-stored potatoes in the presence of dim light (30--40 lux). Isolated chloroplasts from green peelings were able to fix CO2. The evidence obtained showed a direct reduction of CO2 to formate, which was the primary product of fixation. Apart from this the chloroplasts were capable of incorporating NaH14CO3, [14C]formate, [2-14/C]glycine, [2-14C]pyruvate, [2-14C]acetate, [2-14C]mevalonate and [U-14C]serine into the solanidine moiety of the alkaloid. The intermediates in the pathway between CO2 and acetate have been identified as formate, glycine, serine and pyruvate. The localization of the enzymes involved in the reaction sequence viz. serine hydroxymethyl-transferase, and pyruvic dehydrogenase complex, in the isolated chloroplast has been established.
 ...
PMID:A novel pathway for the synthesis of solanidine in the isolated chloroplast from greening potatoes. 96 41

Threshold temperatures for shivering in acute and chronic hypercapnia were determined in guinea pigs by measuring the time course of cervical cord temperature, skin temperature, oxygen consumption (Vo2), and electrical muscle activity during cold exposure (15 degrees C). Prior to acute exposure to CO2, the shivering threshold was determined in each animal during control conditions breathing air. With increasing CO2 concentrations (5,7.5, and 15% CO2) the shivering thresholds fell to lower temperatures, decreasing by approximately 40 degrees C at 15% CO2. The shift of the shivering threshold to lower values found during acute exposure to 15% CO2 was reversed after chronic exposure to 15% CO2 for 3 days, which marks the time of metabolic adaptation to CO2.
 ...
PMID:Threshold temperatures for shivering in acute and chronic hypercapnia. 97 34

The ability of cysts of the brine shrimp, Artemia salina, to incorporate 14CO2 into organic compounds soluble in cold-trichloroacetic acid was examined over a broad range of cellular water concentrations. Carbon dioxide was not incorporated by cysts containing less than about 0.3 g H2O/g dried cysts, the "critical hydration" for CO2-fixation. This relationship held whether the cysts were hydrated from the liquid or the vapor phase. The incorporation of radioactivity was shown to be due exclusively to metabolic activity in the cellular component of the cyst. Above the critical hydration, the amount of 14CO2 incorporated was a function of cyst water content, but the kinds of metabolites labelled with this precursor, and their relative proportions, were found to be similar in cysts of greatly different hydration. Almost all of the radioactivity was associated with amino acids, Krebs cycle intermediates and related acids, and pyrimidine nucleotides. The fact that the pathway involved with CO2-fixation, and subsequent metabolism of the fixation products are all initiated in cysts containing as little as 0.3 g H2O/g is particularly noteworthy since this hydration level is well within the range of the amounts of "bound water" described in the literature for a wide array of cells and tissues.
 ...
PMID:Interrelationships between water and cellular metabolism in Artemia cysts. V. 14CO2 incorporation. 97 57


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