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PubMed1977

Effects of therapy on maximal walking time following femoral ligation in the rat.

Maximal walking times at a constant rate of 10 m/min were compared in normal rats, normal rats that had been exercised daily for 6 weeks, and rats that had undergone bilateral femoral artery ligation followed by 6 weeks of either an oral vasodilator, absence of sympathetic impulses to the extremities, cold exposure, or daily exercise. Rats maintained on the vasodilator could walk no farther than untreated, ligated rats. Both chronic cold exposure and sympathectomy significantly increased maximal walking distances of ligated rats and daily exercise increased maximal walking distances 7-fold. Rats that had received 6 weeks of exercise training following femoral artery ligation could walk longer than normal untrained rats; therefore, the increased exercise tolerance could not be explained solely by the restoration of normal large artery conductance by enlargement of collaterals bypassing the femoral occlusion.

Animals↗
PubMed1998

Low-oxygen stress and water deficit induce cytosolic pyruvate orthophosphate dikinase (PPDK) expression in roots of rice, a C3 plant.

Pyruvate orthophosphate dikinase (PPDK) is known for its role in C4 photosynthesis but has no established function in C3 plants. Abscisic acid, PEG and submergence were found to markedly induce a protein of about 97 kDa, identified by microsequencing as PPDK, in rice roots (C3). The rice genome was found to contain two ppdk loci, osppdka and osppdkb. We isolated osppdka cDNA, which encodes a cytosolic rice PPDK isoform of 96.6 kDa, that corresponded to the ABA-induced protein from roots. Western blot analysis showed a PPDK induction in roots of rice seedlings during gradual drying, cold, high salt and mannitol treatment, indicating a water deficit response. PPDK was also induced in the roots and sheath of submerged rice seedlings, and in etiolated rice seedlings exposed to an oxygen-free N2 atmosphere, which indicated a low-oxygen stress response. None of the stress treatments induced PPDK protein accumulation in the lamina of green rice seedlings. Ppdk transcripts were found to accumulate in roots of submerged seedlings, concomitant with the induction of alcohol dehydrogenase 1. Low-oxygen stress triggered an increase in PPDK activity in roots and etiolated rice seedlings, accompanied by increases in phosphoenolpyruvate carboxylase and malate dehydrogenase activities. The results indicate that cytosolic PPDK is involved in a metabolic response to water deficit and low-oxygen stress in rice, an anoxia-tolerant species.

Abscisic Acid↗
PubMed1980

The role of cyproheptadine in the treatment of cold urticaria.

Histamine release in cold urticaria was studied before and after therapy with cyproheptadine to determine whether any effect upon histamine release could be distinguished from end-organ receptor-site blockade. Patients were asymptomatic while taking cyproheptadine, their ice cube test reverted to normal, and only one of six patients had any swelling upon ice-water submersion of one hand for 5 min. Histamine-release curves were obtained following ice-water submersion before and after cyproheptadine therapy. All patients had significant histamine release and in five of six patients there was no evident difference in the magnitude of histamine release before or after therapy. A single patient did have diminished histamine release after therapy, but could not be restudied to be sure this was not a spurious result. Our data demonstrated that cyproheptadine is extremely effective in ameliorating the symptoms and signs of cold urticaria and that its principal effect is that of an H1 receptor antagonist, thereby blocking the effects of histamine. These data further suggest that a sufficient dose of any standard antihistamine should be similarly effective and that patients who do not tolerate cyproheptadine or do not appear to respond to it should be tried on other antihistamines of the H1 type.

Cold Temperature↗
PubMed1984

Therapeutic approaches to the common cold in children.

In a five-day, randomized, double-blind study, the efficacy and safety of a syrup containing a combination of azatadine maleate, pseudoephedrine sulfate, and dextromethorphan hydrobromide (SCH 399 syrup) were compared with those of an expectorant containing the antihistamine diphenhydramine hydrochloride in 60 children with symptoms of the common cold and associated cough. One-half teaspoonful of assigned medication was administered three or four times daily. The severity of signs and symptoms was graded on days 0, 3, and 5. At days 3 and 5, patients treated with SCH 399 experienced a significantly greater degree of relief (P less than 0.001) than did patients treated with the expectorant product. Differences between treatment groups in overall therapeutic response, as evaluated by the physician, were statistically significant (P less than 0.001) at each visit, favoring patients treated with SCH 399. More than 75% of the patients treated with SCH 399 demonstrated an excellent therapeutic response. Tolerance to both study medications was excellent.

Antitussive Agents↗
PubMed2001

Investigating the effects of anxiety sensitivity and coping on the perception of cold pressor pain in healthy women.

Research indicates that anxiety sensitivity may be related to the negative experience of pain, especially amongst women. Further evidence with chronic pain patients indicates that anxiety sensitivity may result in avoidance pain-coping strategies. However, this effect has not yet been experimentally investigated in healthy groups. Therefore, the current study sought to investigate the effect of anxiety sensitivity and coping on women's responses to pain. Thirty women who were classified as high in anxiety sensitivity and 30 women classified as low in anxiety sensitivity participated. Within each anxiety sensitivity group, half the participants (n = 15) were randomly instructed to either focus on or avoid cold pressor pain sensations. As expected, women high in anxiety sensitivity were found to report higher levels of sensory and affective pain. Also, and consistent with previous research into anxiety sensitivity, no differences were found between anxiety sensitivity groups for measures of pain threshold or pain tolerance. The pain coping instruction manipulation was found to moderate pain experience, in that the avoidance strategy resulted in higher pain ratings compared to when instructed to focus. Finally, high anxiety sensitive women reported greater pain when instructed to avoid rather than focus on cold pressor pain. These results are discussed in light of previous research and future directions for pain management.

Adaptation, Psychological↗
PubMed2005

Cyclic electron flow around PSI monitored by afterglow luminescence in leaves of maize inbred lines (Zea mays L.): correlation with chilling tolerance.

Maize (Zea mays L.) inbred lines of contrasting chilling sensitivity (three tolerant, three sensitive lines) were acclimated to 280 mumol photons m(-2) s(-1) white light at a 17 degrees C sub-optimal temperature. They showed no symptoms of photoinhibition, despite slight changes in photosystem II (PSII) fluorescence and thermoluminescence properties in two tolerant lines. A luminescence "afterglow" emission [Bertsch and Azzi (1965) Biochim Biophys Acta 94:15-26], inducible by a far-red (FR) illumination of unfrozen leaf discs, was detected either as a bounce in decay kinetics at constant temperatures or as a sharp thermoluminescence afterglow band at about 45 degrees C, in dark-adapted leaves. This band reflects the induction by warming of an electron pathway from stromal reductants to plastoquinones and to the Q(B) secondary acceptor of PSII, resulting in a luminescence-emitting charge recombination in the fraction of centres that were initially in the S(2/3)Q(B) non-luminescent state. A 5-h exposure of plants to growth chamber light shifted this luminescence emission towards shorter times and lower temperatures for several hours in the three chilling-tolerant lines. This downshift was not observed, or only transiently, in the three sensitive lines. In darkness, the downshifted afterglow band relaxed within hours to resume its dark-adapted location, similar for all maize lines. A faster dark re-reduction of P700(+) oxidized by FR light (monitored by 820-nm absorbance) and an increase of photochemical energy storage under FR excitation (determined by photoacoustic spectroscopy) confirmed that a cyclic pathway induced by white actinic light remained activated for several hours in the tolerant maize lines.

Cold Temperature↗
PubMed2005

Role of membrane transport of water and glycerol in the freeze tolerance of the rice stem borer, Chilo suppressalis Walker (Lepidoptera: Pyralidae).

Overwintering larvae of the rice stem borer, Chilo suppressalis accumulate glycerol and are freezing tolerant to about -25 degrees C. However, non-diapausing larvae cannot accumulate glycerol and are killed by freezing. We compared the extent of tissue damage, the effects of glycerol concentration, and the transport of glycerol and water in fat body tissues from these larvae at selected freezing temperatures. Tissues from overwintering larvae, but not non-diapausing larvae, survive when frozen at -20 degrees C with 0.25 M glycerol, but the protection afforded by glycerol is offset by the water-channel inhibitor mercuric chloride. Glycerol in higher concentration (0.75 M) affords some protection even to the fat body of non-diapausing larvae. Radiotracer assays of overwintering larvae show that water leaves the tissues during freezing while glycerol enters, and that mercuric chloride disrupts this process. Transport is also disrupted after lethal freezing at -35 degrees C. Therefore, membrane transport of water and glycerol is involved in the avoidance of freezing injury to fat body cells of the rice stem borer, apparently by mediating the replacement of water with glycerol in freezing-tolerant tissues.

Animals↗
PubMed2002

Transcription factors in plant defense and stress responses.

Transcriptional control of the expression of stress-responsive genes is a crucial part of the plant response to a range of abiotic and biotic stresses. Research carried out in the past few years has been productive in identifying transcription factors that are important for regulating plant responses to these stresses. These studies have also revealed some of the complexity and overlap in the responses to different stresses, and are likely to lead to new ways to enhance crop tolerance to disease and environmental stress.

Cold Temperature↗
PubMed1990

Effect of codeine on the sensations elicited by loaded breathing.

The present study examined the effect of codeine, a centrally acting opiate, on the respiratory sensations elicited in normal subjects by breathing to exhaustion against externally applied inspiratory threshold loads. Subjects were tested on two separate days following the double-blind, randomized administration of either placebo or codeine (90 mg). The intensity of the sensations of effort and discomfort experienced during two loaded breathing trials (a "high" load that was 73% of the maximum inspiratory pressure (MIP) and a "low" load that was 63% of the MIP) was evaluated using category (Borg) scores on each day of study. To verify that the dosage of codeine administered was sufficient to produce analgesia, we also determined the effect of this dosage on the time that subjects could tolerate immersion of one hand in ice water. Codeine altered neither the perceived effort nor the sense of discomfort associated with breathing against external loads and had no appreciable effect on the time to exhaustion during loaded breathing trials. This dose of codeine did, however, increase the time that ice water immersion could be tolerated and reduced the rate at which the sense of discomfort increased over time during ice water trials. These results indicate that, provided the pressure-time index of respiratory muscle contraction remains constant, analgesic doses of codeine alter neither the sensations elicited by loaded breathing nor the total time that breathing against a fatiguing inspiratory load can be tolerated.

Adult↗
PubMed2006

Simple improvement in freeze-tolerance of bakers' yeast with poly-gamma-glutamate.

We examined the effect of poly-gamma-glutamate (PGA) on the freeze-tolerance of four types of commercial bakers' yeast (freeze-tolerant, osmotic-tolerant, low-temperature-sensitive, and ordinary bakers' yeasts). The survival ratio of ordinary bakers' yeast cells frozen at -30 degrees C for 3 d in a medium (0.5% yeast extract, 0.5% peptone, and 2% glucose: YPD medium) was improved by adding more than 1% PGA to the medium; the survival ratio increased from about 10% to more than 70%. All PGA preparations, which differed in average molecular mass (50, 2,000, 4,000, 6,000, 8,000, and 10,000 kDa), showed a similar cryoprotecive effect on the cells. Similar results were also obtained with other types of bakers' yeast, sake yeast and beer yeast. When the four types of bakers' yeast cell were frozen at -30 degrees C for 3 d in dough supplemented with more than 1% PGA, the cells (after freezing and thawing) showed higher leavening ability than those frozen in dough without PGA, irrespective of the molecular mass of PGA. Thus, PGA appears to protect bakers' yeast from lethal freeze injury, leading to a high leavening ability after freezing and thawing. PGA did not decrease the original leavening ability of the bakers' yeast, and was not decomposed by the yeast cells. PGA suppressed the decrease in leavening ability during a prolonged fermentation time, probably because PGA adsorbed inhibitory metabolites accumulated in the dough. PGA could prove useful for improving the freeze-tolerance of bakers' yeast by its addition to dough.

Cold Temperature↗
PubMed1994

Low Temperature-Induced Cytoplasmic Acidosis in Cultured Mung Bean (Vigna radiata [L.] Wilczek) Cells.

Cold-induced changes in vivo in the cytoplasmic pH of suspension-cultured cells of mung bean (Vigna radiata [L.] Wilczek) were investigated by fluorescence-ratio imaging cryomicroscopy with special reference to the variations in the chilling sensitivity of cells during the growth cycle. Because of the preferential localization of the fluorophore in the cytoplasm under specified conditions and the ideal response of fluorescence to pH, fluorescein diacetate allows measurements to be made of temporal changes in cytoplasmic pH at low temperature. A remarkable difference was demonstrated in the cold-induced changes in cytoplasmic pH between cells at the early and late stages of exponential growth. The cells at the early stage of exponential growth were most sensitive to chilling, and the cytoplasmic pH decreased dramatically within a short period of incubation at 0[deg]C, decreasing from 7.4 to 6.8 after 4 h and to 6.3 after 18 h. The cells at the late stage of exponential growth were chilling tolerant, and no significant decrease in the cytoplasmic pH was observed during the incubation at 0[deg]C for 24 h or even longer. From the results presented here, it appears that cold-induced cytoplasmic acidosis is characteristic of chilling-sensitive mung bean suspension-cultured cells.

Journal Article↗
PubMed1981

The role of body mass in thermoregulation.

Inbred Fisher and Buffalo rats were raised in small and in large litters and by such litter manipulation, large- and small-bodied animals were obtained within the same strain. When the rats were exposed to extreme cold and heat, it appeared that large-bodied rats in both strains survived longer in cold and small-bodied rats survived longer in heat. The two trends were clearly evident, and individual correlations between survival time and body mass were generally significant. However, there were also irregularities in such correlations. It is concluded that this is due to the fact that body mass is only one factor determining temperature tolerance in addition to hypothalamic, endocrine, and possibly neurochemical factors not known to be correlated to body mass.

Animals↗
PubMed2005

Use of 0.06% ipratropium bromide nasal spray in children aged 2 to 5 years with rhinorrhea due to a common cold or allergies.

BACKGROUND: Rhinorrhea from common colds or allergies in children is similar to that in adults, yet there are few data on the use of ipratropium bromide nasal spray in children younger than 5 years. OBJECTIVE: To evaluate the safety and efficacy of 0.06% ipratropium bromide nasal spray in 2- to 5-year-old children with rhinorrhea from a common cold or allergies. METHODS: A total of 230 children (43 with common colds and 187 with allergies) participated in an open-label, multicenter study. Patients with a common cold received ipratropium bromide nasal spray (84 microg per nostril) 3 times daily for 4 days; those with allergies received ipratropium bromide nasal spray (42 microg per nostril) 3 times daily for 14 days. RESULTS: In the common cold and allergy groups, 91% and 90% of the parents, respectively, found that ipratropium bromide was either "very useful" or "somewhat useful." Furthermore, 67% and 91% of parents in the common cold and allergy groups, respectively, found that administration of a nasal spray was either "extremely easy" or "very easy." Symptom scores were improved from baseline in both groups. The nasal spray was well tolerated and was not associated with serious or systemic anticholinergic adverse effects. Most adverse events were infrequent and mild to moderate, and study discontinuation due to an adverse event occurred in less than 3% of patients. CONCLUSIONS: The 0.06% ipratropium bromide nasal spray, 42 or 84 microg per nostril 3 times daily, is easy to administer, safe, and effective for the control of rhinorrhea in children aged 2 to 5 years with a common cold or allergies.

Administration, Intranasal↗
PubMed2004

Phylogenetic analyses in cornus substantiate ancestry of xylem supercooling freezing behavior and reveal lineage of desiccation related proteins.

The response of woody plant tissues to freezing temperature has evolved into two distinct behaviors: an avoidance strategy, in which intracellular water supercools, and a freeze-tolerance strategy, where cells tolerate the loss of water to extracellular ice. Although both strategies involve extracellular ice formation, supercooling cells are thought to resist freeze-induced dehydration. Dehydrin proteins, which accumulate during cold acclimation in numerous herbaceous and woody plants, have been speculated to provide, among other things, protection from desiccative extracellular ice formation. Here we use Cornus as a model system to provide the first phylogenetic characterization of xylem freezing behavior and dehydrin-like proteins. Our data suggest that both freezing behavior and the accumulation of dehydrin-like proteins in Cornus are lineage related; supercooling and nonaccumulation of dehydrin-like proteins are ancestral within the genus. The nonsupercooling strategy evolved within the blue- or white-fruited subgroup where representative species exhibit high levels of freeze tolerance. Within the blue- or white-fruited lineage, a single origin of dehydrin-like proteins was documented and displayed a trend for size increase in molecular mass. Phylogenetic analyses revealed that an early divergent group of red-fruited supercooling dogwoods lack a similar protein. Dehydrin-like proteins were limited to neither nonsupercooling species nor to those that possess extreme freeze tolerance.

Cornus↗
PubMed1976

Body temperature in mice: a quantitative measure of alcohol tolerance and physical dependence.

Mice undergoing withdrawal after chronic ethanol consumption were found to be hypothermic if kept at room temperature. The extent of the hypothermia correlated well with the behavioral withdrawal symptoms and could be used as a quantitative measure of the severity and time course of the withdrawal syndrome. Placing mice in a cold environment (4 degrees C) exacerbated the hypothermia whereas placing animals at 34 degrees C reversed the hypothermia and produced hyperthermia. It was concluded that the temperature set point mechanism and the ability to regulate around this set point was disturbed in animals physically dependent on alcohol. During consumption of the ethanol-containing diets, mice exhibited tolerance to the hypothermic effects of an acutely administered dose od ethanol. Tolerance to the hypothermic effects of ethanol mirrored the development of behavioral tolerance as measured by performance on a tilting plane. Temperature and behavioral tolerance were both shown to extend well beyond the period of the withdrawal syndrome. Ethanol-treated mice were found to be cross-tolerant to the hypothermic effects of barbiturates but not to the hypothermia produced by the monoamine oxidase inhibitor, pargyline.

Animals↗
PubMed2000

[Cytotoxicity evaluation of three tear substitutes used in the treatment of dry eye syndromes].

PURPOSE: To investigate cell tolerance of three tear substitutes used in the treatment of dry eye syndromes. METHODS: Cytotoxicity tests were done on a continuous human conjunctival cell line using microplate cold light cytofluorimetry. Membrane integrity, DNA condensation and reactive oxygen species (ROS) production (hydrogen peroxyde and superoxide anion) were evaluated after 15 minutes of treatment or 15 minutes and 24 hours of cell recovery. Hyaluronic acid, hydroxypropyl methylcellulose associated with sodium perborate (HPMC) and carbomer 934P were tested at their commercial concentrations (respectively 0.18%, 0.3% and 0.3%) and after a 1/10 dilution. RESULTS: Cell viability and chromatin condensation were not altered by hyaluronic acid for all concentrations and times tested. A decrease in membrane integrity was observed with 0.3% carbomer 934P after 24 hours of cell recovery and with 0.3% HPMC after 15 minutes. This decrease was amplified after 24 hours and associated with an apoptotic phenomenon. A H(2)O(2) production was observed with HPMC associated with sodium perborate and an O(2) production was found with hyaluronic acid diluted at 1/10. CONCLUSION: Hyaluronic acid, carbomer and HPMC are in vitro well-tolerated even if HPMC induces a more important decrease of cell viability compared to the other drugs. Hyaluronic acid, with its rheologic properties, with no in vitro toxicity, seems to be efficient for dry eye patients.

Borates↗