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PubMed1990

Regeneration of Freezing-Tolerant Spring Wheat (Triticum aestivum L.) Plants from Cryoselected Callus.

A cryoselection protocol has been developed that provides freezing-tolerant callus that, in turn, can regenerate plants with enhanced cold hardiness. Tolerant calli were selected from spring wheat (Triticum aestivum L.) callus by immersion in liquid nitrogen without addition of cryoprotectants. Less than 15% of the calli survived the initial challenge, whereas 30 to 40% of previously selected calli survived subsequent exposure. Seed progeny from five of 11 regenerant (R2) lines tested exhibited significantly enhanced tolerance to freezing at -12 degrees C. Thus, cryoselection appears to involve at least in part, selection for genetic rather than epigenetic variants. Analysis of one callus line indicated that cryoselection did not induce significant alterations in lipid composition, adenylate energy charge, or freezing point. An increase in the soluble sugar component was detected. Changes were also detected in the protein complement of microsomal membrane and soluble protein extracts of cryoselected callus. In all, seven unique proteins ranging from 79 to 149 kilodaltons were identified. The results demonstrate that freezing tolerant callus can be isolated from a heterogeneous population by cryoselection, and factors that contribute to hardiness at the callus level are biologically stable and can contribute to tolerance at the whole plant level.

Journal Article↗
PubMedDate not supplied

Cold urticaria associated with acute serologic toxoplasmosis.

Cold urticaria is defined as a urticarial and/or angioedematous reaction of the skin to contact with cold objects, water or air. Types of urticaria associated with infectious diseases, such as mononucleosis, rubeola, varicella, syphilis, hepatitis, and HIV infection have been reported. We present the case of a patient who developed cold urticaria associated with acute serologic toxoplasmosis. The patient was a 34-year-old man who for the previous 2 months had presented cutaneous pruritus accompanied by several papular lesions in parts of the skin exposed to cold as well as those in contact with cold water. The result of an "ice-cube test" was positive. Serologic tests for Toxoplasma gondii showed an IgG level of 68 UI/ml and were positive for IgM, while a test for cryoglobulins was positive. One month later cryoglobulins were negative and a serologic test for T. gondii showed an IgG concentration of 75 UI/ml and positive IgM. Three months later cryoglobulins were still negative, IgG for T. gondii was 84 UI/ml, and IgM was positive. After 6 months cryoglobulins were still negative, IgG level was 68 UI/ml and IgM was still slightly positive. In the final evaluation, 14 months later, IgG level was 32 UI/ml and IgM was negative. The patient continues to present clinical manifestations of cold urticaria, although he has experienced some improvement and his tolerance to cold has increased after treatment with cetirizine.

Acute Disease↗
PubMed2002

Male sterility thermal thresholds in Drosophila: D. simulans appears more cold-adapted than its sibling D. melanogaster.

Numerous different criteria may be used for analysing species thermal adaptation. We compared male sterility thresholds in the two most investigated cosmopolitan siblings, D. melanogaster and D. simulans. A survey of various populations from Europe and North Africa evidenced consistent differences between the two species, and a detailed analysis was made on flies from Marrakech. Sharp sterility thresholds were observed in both species but at different temperatures: D. simulans appeared more tolerant to cold than its sibling (difference 1 degrees C) but more sensitive to heat (difference 1.5 degrees C). When transferred to an optimum temperature of 21 degrees C, D. simulans males, sterilized by a low temperature, recovered more rapidly than males of D. melanogaster; the reverse was true on the high temperature side. The analysis of progeny number also revealed the better tolerance of D. simulans males to cold but a lesser tolerance to heat. From these observations, we might expect that D. simulans should be more successful in cold temperate countries than its sibling, while ecological observations point to the contrary. Our data clearly show the difficulty of comparing ecophysiological data to field observations, and also the need of extensive comparative life history studies in closely related species.

Adaptation, Physiological↗
PubMed2000

Early steps in cold sensing by plant cells: the role of actin cytoskeleton and membrane fluidity.

Many plants acquire freezing tolerance through cold acclimatization (CA), a prolonged exposure to low but non-freezing temperatures at the onset of winter. CA is associated with gene expression that requires transient calcium influx into the cytosol. Alfalfa (Medicago sativa) cells treated with agents blocking this influx are unable to cold-acclimatize. Conversely, chemical agents causing increased calcium influx induce cold acclimatization-specific (cas) gene expression in alfalfa at 25 degrees C. How low temperature triggers calcium influx is, however, unknown. We report here that induction of a CA-specific gene (cas30), calcium influx and freezing tolerance at 4 degrees C are all prevented by cell membrane fluidization, but, conversely, are induced at 25 degrees C by membrane rigidification. cas30 expression and calcium influx at 4 degrees C are also prevented by jasplakinolide (JK), an actin microfilament stabilizer, but induced at 25 degrees C by the actin microfilament destabilizer cytochalasin D (CD). JK blocked the membrane rigidifier-induced, but not the calcium channel agonist-induced cas30 expression at 25 degrees C. These findings indicate that cytoskeleton re-organization is an integral component in low-temperature signal transduction in alfalfa cell suspension cultures, serving as a link between membrane rigidification and calcium influx in CA.

Actins↗
PubMed1998

Post pupariation cold storage of three species of flies: increasing chilling tolerance by acclimation and recurrent recovery periods.

Three species of flies were examined for chilling tolerance from the end of the pupariation to the onset of adult eclosion for the purpose of determining applicability for cold storage. For the housefly, Musca domestica (Diptera, Muscidae), survival to eclosion was affected by developmental stage/age, length of storage, and storage temperature. Houseflies that were closest to having experienced pupariation or the onset of eclosion were the least cold tolerant. For flies stored at 7 or 10 degrees C, age groups placed directly into storage at 36-72 and 36-48 h postpupariation, respectively, had significantly higher poststorage eclosion than younger or older age groups. Death was observed after only 2 or 3 days with the chilling intolerant groups while mid-aged groups survived 10-12 days under cold storage conditions. Damage could be reduced by giving the mid-aged groups chilled at 7 or 10 degrees C recurrent 2- or 3-h recovery periods every 4 days at 28 degrees C. Examination of O2 consumption throughout the housefly pupal and pharate adult stages showed that the most chilling tolerant groups also had the lowest metabolic activity. Combining a prestorage 17-h slow cooling acclimation interval with the recurrent recovery periods increased eclosion of adults 20% for the 12- to 24-h group after 21 days storage at 7 degrees C. Two blowfly species, Lucilia cuprina and Lucilia sericata (Diptera, Calliphoridae), survived 10 degrees C storage best when given a weekly 4-h recovery period. Survival at 90 days poststorage was nearly 50% for L. cuprina and 80% for L. sericata. Increasing survival under subambient temperatures for all three species appears to relate to whether there is a stage of development which allows cold-induced lowering of metabolism that results in a dormant status best characterized as hibernal quiescence. This study indicates that periodic warming during cold storage increases survival by allowing a chilling intolerant stage to develop to a more tolerant stage and/or by eliminating accumulated toxic metabolites.

Adaptation, Biological↗
PubMed1998

Effects of rearing temperature on body weight and abdominal fat in male and female rats.

Thermoregulatory mechanisms are influenced by the temperature of the postnatal environment. Animals reared in cool environments are more tolerant of cold as adults, whereas those reared in warm conditions are more tolerant of heat. Because diet-induced and thermoregulatory thermogenesis share common features, studies examined the impact of rearing temperature on weight gain and fat accumulation. Rats reared at 18 degrees C gained more weight and accumulated more fat in abdominal depots than animals reared at 30 degrees C when both were housed at a common temperature, responses that were exacerbated by ad libitum access to sucrose. Male rats reared at 30 degrees C were less affected by sucrose than 18 degrees C-reared males, whereas female rats reared at 18 or 30 degrees C were similarly susceptible. During exposure to 18 degrees C, fat accumulation in abdominal depots increased in males but decreased in females. These data suggest that early temperature exposure influences weight gain and fat accumulation in later life, a difference that is most apparent when animals are housed at a common temperature.

Abdomen↗
PubMed1995

Changes in motoneuron membrane potential and reflex activity induced by sudden cooling of isolated spinal cords: differences among cold-sensitive, cold-resistant and freeze-tolerant amphibian species.

The effects of sudden cooling of the spinal cord were studied in three species of amphibians--a cold-sensitive tropical toad (Bufo marinus), a cold-resistant, aquatic, hibernating frog (Rana pipiens, northern leopard frog) and a freeze-tolerant frog (Rana sylvatica, wood frog). Ventral root (motoneuron) potentials were recorded from isolated, hemisected spinal cords of each species mounted in a sucrose-gap recording apparatus and superfused with HCO3(-)-buffered Ringer's solution at room temperature (21 degrees C). In the toad, sudden cooling to 6-8 degrees C produced large, sustained motoneuron depolarizations that returned slowly to baseline levels and were accompanied by extensive paroxysmal activity. Larger, but shorter-lasting, motoneuron depolarizations associated with only a limited amount of paroxysmal activity were generated by rapid cooling of the leopard frog spinal cord. Small, brief motoneuron depolarizations followed by a hyperpolarization, or hyperpolarizations not preceded by depolarizations, were seen in cooled wood frog spinal cords. The wood frog displayed a large amount of spontaneous motoneuron activity, but little paroxysmal activity in response to sudden cooling. Following prolonged cooling, rewarming the spinal cords of all three species resulted in motoneuron hyperpolarizations that slowly decayed towards the baseline value. The amplitude of the rewarming-induced response was larger and longer in toad motoneurons than in leopard frog and wood frog motoneurons. At room temperature, a single supramaximal dorsal root stimulus evoked a depolarizing ventral root potential in toad and leopard frog motoneurons that was decreased in amplitude and prolonged when the spinal cords were cooled to 8 degrees C or below. In contrast, at room temperature, the ventral root reflex in the wood frog was followed by a distinct hyperpolarization. Cooling the wood frog spinal cord only slightly reduced the amplitude of the ventral root potential. In contrast, the evoked hyperpolarization was blocked by sudden cooling and also by the addition of dihydro-ouabain to the Ringer's solution. The motoneuron hyperpolarizations induced by sudden cooling in the wood frog were converted to depolarizations when Cl- in the superfusate was replaced with isethionate. The depolarizations elicited by sudden cooling were reduced by the addition of kynurenate in all three species. A dose-response curve generated by short applications of L-glutamate demonstrated that wood frog motoneurons were less sensitive than leopard frog motoneurons to L-glutamate. In summary, three species of amphibians, differing in their adaptations to the temperature of their environments, vary in their responses to sudden reductions in temperature. The relationship of these responses to their environmental adaptations remains to be determined.

Animals↗
PubMed1989

Synthesis of Freezing Tolerance Proteins in Leaves, Crown, and Roots during Cold Acclimation of Wheat.

Protein synthesis was studied in leaves, crown, and roots during cold hardening of freezing tolerant winter wheat (Triticum aestivum L. cv Fredrick and cv Norstar) and freezing sensitive spring wheat (T. aestivum L. cv Glenlea). The steady state and newly synthesized proteins, labeled with [(35)S]methionine, were resolved by one- and two-dimensional polyacrylamide gels. The results showed that cold hardening induced important changes in the soluble protein patterns depending upon the tissue and cultivar freezing tolerance. At least eight new proteins were induced in hardened tissues. A 200 kilodalton (kD) (isoelectric point [pl] 6.85) protein was induced concomitantly in the leaves, crown, and roots. Two proteins were specifically induced in the leaves (both 36 kD, pl 5.55 and 5.70); three in the crown with M(r) 150 (pl 5.30), 45 (pl 5.75), and 44 kD (pl > 6.80); and two others in the roots with M(r) 64 (pl 6.20) and 52 kD (pl 5.55). In addition, 19 other proteins were synthesized at a modified rate (increased or decreased) in the leaves, 18 in the crown and 23 in the roots. Among the proteins induced or increased in hardened tissues, some were expressed at a higher level in the freezing tolerant cultivars than in the sensitive one, indicating a correlation between the synthesis and accumulation of these proteins and the degree of freezing tolerance. These proteins, suggested to be freezing tolerance proteins, may have an important role in the cellular adaptation to freezing.

Journal Article↗
PubMed1999

A Danish adaptation of the Pain Coping Questionnaire for children: preliminary data concerning reliability and validity.

The aim of this study was to determine the reliability and validity of a Danish translation of the Pain Coping Questionnaire (PCQ) for children in Danish children. The PCQ was translated using a translation-back-translation method. The subjects were 352 healthy children and 40 children with juvenile arthritis (JA), aged 8-17 y. Sixteen of the JA children were divided into a high-pain group (n = 7) and a low-pain group (n = 9). The results were factor analysed using principal component analysis with varimax rotation. Clinical pain intensity was measured using visual analogue scales (VAS) from the Varni/Thompson Pediatric Pain Questionnaire. Experimental pain was induced using a cold pressor pain paradigm and outcome measures were pain intensity, pain discomfort and tolerance to cold pressor pain. A seven-factor solution emerged as the most consistent factor structure. Four subscales, Seeking Social Support (SSS), Cognitive Distraction (CD), Externalizing (EXT) and Internalizing/Catastrophizing (INT), corresponded with the parallel subscales proposed by Reid et al. (Pain 1998; 76: 83-96). Two subscales, Positive Self-Statements (PSS) and Behavioral Distraction (BD), were composed of four of the five items from the previously proposed subscales. One subscale, Information Seeking/Problem Solving (IP), consisted of items from two subscales proposed by Reid et al., i.e. Information Seeking and Problem Solving. Internal consistencies of the subscales were acceptable, with reliability coefficients ranging from 0.60 (BD) to 0.83 (IP) and with test-retest reliabilities between 0.59 and 0.78. Low-pain JA patients showed significantly higher levels of BD than High-pain JA patients (p<0.05). Greater utilization of PSS and BD was associated with less patient-reported present pain and less average everyday pain (p<0.05-0.01), and greater utilization of INT was significantly associated with higher experimental pain intensity (p<0.01). These preliminary findings provide support for the reliability and validity of the Danish modification of the PCQ in a Danish population and for the hypothesis that paediatric pain-coping strategies are associated with the intensity of clinical and experimental pain.

Adaptation, Psychological↗
PubMed2006

[Experimental study on tolerance time limits from warm ischemia to cold preservation of liver grafts].

OBJECTIVE: To investigate the tolerance time limits from warm ischemia to cold preservation of liver grafts. METHODS: Orthotopic liver transplantations (OLTs) were performed on Bama miniature swine. Morphological and functional changes of the liver grafts and biliary tracts after 10 minutes of warm ischemia followed by different durations of cold preservation and its reversibility were investigated. RESULTS: When the grafts were subjected to 10 minutes of warm ischemia followed by less than 16 hours of cold preservation, all animals could survive 1 week and there was no animal death from biliary necrosis. However, when the cold preservation time exceeded 16 hours, the incidence of biliary necrosis was significantly increased (P<0.05), and recipient death from bile leaks occurred. With further prolongation of the cold preservation time, primary graft nonfunction and intraoperative or early postoperative deaths occurred and the living animals all developed biliary necrosis. When compared with the less than 16 hours cold preservation group, the morphological scores and apoptosis index of the epithelial cells of bile ducts in grafts after reperfusion were significantly elevated in the more than 16 hours cold preservation group (P<0.05) and the activity of Na+-K+-ATPase and Ca2+-ATPase of bile ducts in grafts were also significantly reduced (P<0.05). Liver function tests showed that the recoveries of AST, AST, GGT and ALP were quicker in the 16 hours cold preservation group then those over 16 hour preservation ones. Correlation analysis revealed that the incidence of biliary necrosis was significantly correlated with the morphological score (r = 0.972) and with the apoptosis index of the epithelial cells of bile ducts in grafts after reperfusion (r = 0.931) and also correlated negatively (P<0.01) with the activity of Na+-K+-ATPase (r = -0.973) and Ca2+-ATPase (r = -0.973). CONCLUSIONS: It is concluded that with 10 minutes of warm ischemia, cold preservation of the grafts should not be longer than 16 hours in order to avoid early biliary necrosis, and the corresponding tolerance time limit of the livers to the cold preservation was less than 20 hours.

Animals↗
PubMed1975

Reduced urinary noradrenaline excretion during rest, exercise and cold stress in trained rats: a comparison between physically-trained rats, cold-acclimated rats and warm-acclimated rats.

Physically trained rats were compared with cold-acclimated rats. Trained as well as cold-acclimated rats showed cardiac and adrenal hypertrophy. Cardiac noradrenaline (NA) content was increased in both groups of rats but only the trained rats had an increased cardiac NA concentration. The adrenal NA content was increased in both groups but only the trained rats had an increased adrenal content of adrenaline (A). The spleen of trained rats had an increased NA content, while that of cold-acclimated rats had a decreased NA content. The submandibular glands of cold-acclimated rats were enlarged and had an increased NA content. Trained as well as cold-acclimated rats had lower urinary NA excretions during rest, after exercise and during cold stress when compared with controls. However, only the trained rats had a reduced net increment in NA excretion after exercise, whereas there was no difference between the increments of cold-acclimated and control rats. Six months after cessation of training, ex-trained rats still had an increased heart ratio and a reduced urinary NA excretion after exercise. It is suggested that physical training induces "cross tolerance" to cold stress, while cold-acclimation does not lead to "cross tolerance" to acute exercise.

Acclimatization↗
PubMed2003

Mass spectrometric approach for identifying putative plasma membrane proteins of Arabidopsis leaves associated with cold acclimation.

Although enhancement of freezing tolerance in plants during cold acclimation is closely associated with an increase in the cryostability of plasma membrane, the molecular mechanism for the increased cryostability of plasma membrane is still to be elucidated. In Arabidopsis, enhanced freezing tolerance was detectable after cold acclimation at 2 degrees C for as short as 1 day, and maximum freezing tolerance was attained after 1 week. To identify the plasma membrane proteins that change in quantity in response to cold acclimation, a highly purified plasma membrane fraction was isolated from leaves before and during cold acclimation, and the proteins in the fraction were separated with gel electrophoresis. We found that there were substantial changes in the protein profiles after as short as 1 day of cold acclimation. Subsequently, using matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS), we identified 38 proteins that changed in quantity during cold acclimation. The proteins that changed in quantity during the first day of cold acclimation include those that are associated with membrane repair by membrane fusion, protection of the membrane against osmotic stress, enhancement of CO2 fixation, and proteolysis.

Acclimatization↗
PubMedDate not supplied

Solute accumulation in heat seedlings during cold acclimation: contribution to increased freezing tolerance.

Accumulation of sugars, amino acids and glycinebetaine in leaf tissues during cold acclimation was simultaneously monitored and compared in three wheat cultivars that have different freezing tolerance. Freezing tolerance was the decreasing order of cv. Norstar (NO) > cv. Chihokukomugi (CH) > or = cv. Haruyutaka (HA). During cold acclimation, there was a significant increase in osmotic concentration in the three cultivars. The increase was largely due to the increase in soluble sugars and the extent of the increase was the greatest in NO and the least in HA. While there was a considerable increase in glucose, fructose and sucrose during the first week of cold acclimation, the increase in raffinose occurred only after the second week. The total sugar content was the order of NO > CH > HA after 4 weeks of cold acclimation. Proline increased in all cultivars after 1 week of cold acclimation but a prolonged cold acclimation resulted in different profiles: no further increase occurred in HA while an additional increase occurred in other two cultivars. In all three cultivars, a noticeable increase of glycinebetaine occurred only after the second week of cold acclimation with the amount being the order of NO > CH > HA. It is concluded that a substantial part of the increase in osmotic concentration during cold acclimation was due to the increase in sugars, but the extent of the contribution of each compatible solute is cultivar-specific and can be associated with the degree of the maximum freezing tolerance attainable.

Acclimatization↗
PubMed2004

Cold acclimation and abscisic acid induced alterations in carbohydrate content in calli of wheat genotypes differing in frost tolerance.

The effect of cold and abscisic acid (ABA) treatment on soluble carbohydrate content was compared in callus cultures of wheat genotypes differing in frost tolerance. The effect of 5A chromosome substituted from the frost tolerant < > to the sensitive < > on cold-induced carbohydrate accumulation was also determined. Following cold hardening, the increase in sucrose and fructan level in calli of tolerant varieties was significantly higher than those of the sensitive ones. In 5A substitution line higher sucrose and fructan content was detected than in recipient < >. Tendentiously, cold stress caused higher degree of changes in carbohydrate content than the exogenously applied ABA did. Comparing the accumulation pattern of the components of WSC measured in vitro to the previously published in vivo results it can be concluded that in the case of sucrose and fructans it was similar, while for the reducing sugars it was different. The regulatory role of chromosome 5A either in the development of freezing tolerance or carbohydrate accumulation was confirmed in dedifferentiated calli, as well.

Abscisic Acid↗
PubMed2001

Extension of ischemic tolerance of porcine livers by cold preservation including postconditioning with gaseous oxygen.

BACKGROUND: Transplantation of organs from nonheartbeating donors was recommended to reduce organ shortage. In vitro experiments with rat livers have shown that the warm ischemic tolerance of the liver may be extended by persufflation with gaseous oxygen during cold storage. The qualification of this method for procurement of livers harvested after cardiac arrest was tested in an in vivo approach with pigs. METHODS: Livers from 15 donor pigs were explanted, heparinized, flushed with and stored in University of Wisconsin solution for 4 hr at 4 degrees C, and then implanted into 15 recipients. The organs were dissected immediately after cardiac arrest (group 1) or after 60 min of warm ischemia (groups 2 and 3). Group 2 livers received 75,000 IU of superoxide dismutase together with the flush solution and were persufflated with gaseous oxygen via the venous vascular system during cold storage. Main end point was survival after 5 days. Additionally, metabolic, functional and inflammatory criteria were measured in the blood. RESULTS: All animals of the groups 1 and 2 survived, all animals of group 3 died within 3 hr after reperfusion. In all groups the blood parameters reflected significant damage of the livers. However, the ischemic damage was comparable in the groups 1 and 2 whereas the livers of group 3 exhibited significantly higher levels of aspartate alanine aminotransferase and lactate dehydrogenase, and a significantly elongated partial thromboplastin time 1 hr after reperfusion (P=0.016). CONCLUSIONS: Venous systemic oxygen persufflation in combination with antioxidative medication is a promising new method of resuscitating ischemically altered livers from nonheartbeating donors for successful transplantation.

Animals↗
PubMed1995

Quantitative assessment of differential sensory nerve block after lidocaine spinal anesthesia.

BACKGROUND: Recent technology allows for quantitative and selective measurement of A beta, A delta, and C fiber nerve transmission. To gain further insight into the physiology of differential block after lidocaine spinal anesthesia, the function of these different fibers was quantitatively measured over time, and these measurements were correlated with regression of anesthesia to pinprick, touch, cold, and tolerance of tetanic electrical current (equivalent to surgical incision). METHODS: Six volunteers received lidocaine spinal anesthesia with 50 mg lidocaine (5% in dextrose). Cutaneous current perception thresholds at 2,000, 250, and 5 Hz, which stimulate A beta, A delta, and C fibers, respectively, were determined at L2-L3 (medial aspect above knee) before and every 10 min after spinal anesthesia. Dermatomal levels to pinprick, touch, and cold were assessed every 5 min after spinal anesthesia. Tolerance to tetanic electrical stimulus was assessed at L2-L3 every 10 min after spinal anesthesia. RESULTS: Differential block was demonstrated by the sequential return of sensation to touch, pinprick, and cold at L2-L3. Recovery of function of A beta, A delta, and C fibers correlated with return of sensation to touch (R2 = 0.7, p = 0.03), pinprick (R2 = 0.75, p = 0.02), and cold (R2 = 0.67, p = 0.04) respectively. Loss of tolerance of surgical anesthesia corresponded to return of A beta current perception thresholds to baseline, whereas current perception thresholds for A delta and C fibers were still increased to greater than baseline (p = 0.025). CONCLUSIONS: Differential sensory block during spinal anesthesia is due to different recovery profiles of A beta, A delta, and C fibers. Return of A beta current perception thresholds to baseline correlated with duration of surgical anesthesia as assessed with an electrical stimulation model.

Anesthesia Recovery Period↗
PubMed1986

The efficacy and tolerance of intranasal interferons: studies at the Common Cold Unit.

Intranasal sprays of interferons (IFNs) given one day before and for three days after virus challenge can protect human volunteers from infection with rhinoviruses, coronavirus, and influenza. Longer dosage of IFN gives rise to nasal symptoms and signs such as bloodstained nasal discharge. More effective IFNs and regimes are therefore needed. IFN beta is active but the degree to which it will irritate the nose is unknown. Combining IFNs with synthetic antiviral drugs can produce synergistic increases in antiviral activity. It is suggested that these increases may be exploited in future experiments.

Administration, Intranasal↗