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At least 451 records · Page 25Linked to original sources
PubMed1992

The effect of dietary sodium on right ventricular failure-induced ascites, gain and fat deposition in meat-type chickens.

Experiments were carried out using various levels of sodium (Na+) from NaCl or NaHCO3 to determine: 1) the level of Na+ required to induce ascites alone or in combination with cold temperature and 2) the effect of Na+ on weight gain and fat deposition in broiler chickens. In experiment 1, there were no cases of ascites using levels of Na+, from NaCl at 0.14% to 0.44% in the feed from day 3 or using added Na+, from NaCl at 0.0% to 0.12% in the water from day 3 with a level of 0.14% in the feed. There was no significant difference in 21 or 42 day body weight, feed conversion, or right ventricle:total ventricle (RV:TV) ratio between treatment groups. Day 3 to 4 body weight gains were significantly increased in all treatment groups with added Na+ (p less than 0.01). In experiment 2, with levels of added Na+, from NaCl, at 0.0% to 0.12% in the water with a level of 0.20% in the feed there were two cases of ascites, one at day 7 and one at day 40 at the 0.12% level. There were no significant differences in body weight at days 21 or 42 or in the RV:TV ratios between groups. Feed conversions were improved (p less than 0.01) with the lowest and highest levels of Na+ and a significant increase in day 3 to 4 body weight gain, with increasing Na+ in all treatment groups, was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed2003

Changes in Escherichia coli transcriptome during acclimatization at low temperature.

Upon cold shock Escherichia coli transiently stops growing and adapts to the new temperature (acclimatization phase). The major physiological effects of cold temperature are a decrease in membrane fluidity and the stabilization of secondary structures of RNA and DNA, which may affect the efficiencies of translation, transcription, and replication. Specific proteins are transiently induced in the acclimatization phase. mRNA stabilization and increased translatability play a major role in this phenomenon. Polynucleotide phosphorylase (PNPase) is one of the cold-induced proteins and is essential for E. coli growth at low temperatures. We investigated the global changes in mRNA abundance during cold adaptation both in wild type E. coli MG1655 and in a PNPase-deficient mutant. We observed a twofold or greater variation in the relative mRNA abundance of 20 genes upon cold shock, notably the cold-inducible subset of csp genes and genes not previously associated with cold shock response, among these, the extracytoplasmic stress response regulators rpoE and rseA, and eight genes with unknown function. Interestingly, we found that PNPase both negatively and positively modulated the transcript abundance of some of these genes, thus suggesting a complex role of PNPase in controlling cold adaptation.

Adaptation, Physiological↗
PubMed2005

Effect of repeated exposures to cold on cognitive performance in humans.

The effects of repeated exposure to cold temperature on cognitive performance were examined in 10 male subjects who were exposed to control (25 degrees C) and cold (10 degrees C) conditions on 10 successive days. A cognitive test battery (ANAM-ICE) was administered each day to assess complex and simple cognitive functioning accuracy, efficiency and response time. Rectal (T(rect)) and skin temperatures, thermal sensations, metabolic rate (M) and cardiovascular reactivity were also recorded. With the used cold exposure, inducing cold sensations and discomfort, superficial skin cooling (6-7 degrees C) and a slightly lowered T(rect) (0.4 degrees C) we observed three distinct patterns of cognitive performance: 1) negative, reflected in increased response times and decreased accuracy and efficiency; 2) positive, reflected in decreased response time and increased efficiency; and 3) mixed, reflected in a pattern of increases in both accuracy and response time and decreases in efficiency, and a pattern of decreases in both accuracy and response time. T(rect), thermal sensations, diastolic blood pressure (DBP) and heart rate (HR) were independent predictors of decreased accuracy, but also decreased response time. Cognitive performance efficiency was significantly improved and response times shorter over the 10-d period both under control and cold exposures suggesting a learning effect. However, the changes in cognitive performance over the 10-d period did not differ markedly between control and cold, indicating that the changes in the thermal responses did not improve performance. The results suggest that cold affects cognitive performance negatively through the mechanisms of distraction and both positively and negatively through the mechanism of arousal.

Acclimatization↗
PubMed1992

Ca(2+)-calmodulin regulated effectors of microtubule stability in bovine brain.

Stable microtubules (as defined by resistance to Ca2+, drug or cold temperature induced disassembly) form in abundance during tubulin assembly in brain crude extracts. We have previously shown that, in rat brain crude extracts, all microtubule stabilizing activity could be ascribed to a single Ca(2+)-calmodulin binding and Ca(2+)-calmodulin regulated protein, called "stable tubule only polypeptide", STOP145 [Pirollet, F., Rauch, C. T., Job, D., & Margolis, R. L. (1989) Biochemistry 28, 835-842]. We have now performed an exhaustive study of STOP-like effectors in bovine brain high-speed supernatants. All activity binds to cation exchangers and to Ca(2+)-calmodulin affinity columns. The activity can be resolved into two peaks on sizing columns. The first eluted peak contains a prominent 220-kDa protein. The second peak contains an apparently homogeneous 20-kDa polypeptide. A monoclonal antibody specific to rat brain STOP145 recognizes the 220-kDa protein, but not the 20-kDa species. The 220-kDa protein can be purified on a STOP antibody column and accounts for the bulk of stabilizing activity in the first peak. The 20-kDa protein does not bind to STOP antibody affinity columns. Sequence analysis of oligopeptide fragments of the 20-kDa protein shows 100% homology with bovine myelin basic protein (MBP). Anti-MBP antibodies recognize the 20-kDa, but not the 220-kDa species. We conclude that the 220-kDa protein is the bovine equivalent to rat brain STOP145 and that the 20-kDa species is MBP. Microtubule stabilization by MBP and STOP220 is abolished in the presence of Ca(2+)-calmodulin, and inhibition curves are similar for both proteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1977

Effect of epinephrine upon irreversible disposal and recycling of glucose in dogs.

Irreversible utilization and recycling of glucose during epinephrine-induced hyperglycemia were studied in adrenal-demedullated dogs exposed to neutral or cold ambient temperature. Whatever the ambient temperature, most of the extra glucose mobilized by epinephrine is recycled rather than irreversibly utilized by the peripheral tissue.

Adrenalectomy↗
PubMed2006

TRPA1 is a substrate for de-ubiquitination by the tumor suppressor CYLD.

Certain TRP cation channels confer the ability to sense environmental stimuli (heat, cold, pressure, osmolarity) across physiological and pathophysiological ranges. TRPA1 is a TRP-related channel that responds to cold temperatures, and pungent compounds that include the cold-mimetic icilin and cannabinoids. The initial report of TRPA1 as a transformation-associated gene product in lung epithelia is at odds with subsequent descriptions of a tissue distribution for TRPA1 that is restricted to sensory neurons. Here, we report that the human TRPA1 protein is widely expressed outside the CNS, and is indeed dys-regulated during oncogenic transformation. We describe that TRPA1 associates with the tumor-suppressor protein CYLD. TRPA1 is a novel substrate for the de-ubiquitinating activity of CYLD, and this de-ubiquitination has the net effect of increasing the cellular pool of TRPA1 proteins. Oncogenic mutations in the CYLD gene may therefore be predicted to alter cellular levels of TRPA1.

Calcium Channels↗
PubMed1971

The independence of electrogenic sodium transport and membrane potential in a molluscan neurone.

1. The current-voltage relations of the Anisodoris giant neurone (G cell) were studied in the presence and absence of Na pump activity.2. Inhibition of the electrogenic Na pump with ouabain had no effect on either the presence at warm temperatures (10-15 degrees C), or absence at cold temperatures (0-5 degrees C), of inward-going rectification.3. Abolition of inward-going rectification in the warm, by replacement of external K with Rb, did not affect the electrogenic Na pump.4. The current generated by the electrogenic pump was essentially constant between the membrane potentials of - 30 and - 100 mV.5. The potential produced by the electrogenic pump can be predicted by a modification of the constant field equation.6. It is estimated that the energy required to extrude Na was between 3160 and 3700 cal/g-atom, and that uncoupled Na efflux during pump activity was typically between 0.2 and 4.0 p-mole/cm(2).sec.

Acetylcholine↗