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PubMed2002

Effects of temperature on intracellular Ca2+ in trout atrial myocytes.

Acute temperature change can be cardioplegic to mammals, yet certain ectotherms maintain their cardiac scope over a wide temperature range. To better understand the acute effects of temperature on the ectothermic heart, we investigated the stimulus-induced change in intracellular Ca(2+) concentration ([Ca(2+)](i); cytosolic Ca(2+) transient) in isolated rainbow trout myocytes at 7 degrees C, 14 degrees C and 21 degrees C. Myocytes were voltage-clamped and loaded with Fura-2 to measure the L-type Ca(2+) channel current (I(Ca)) and [Ca(2+)](i) during physiological action potential (AP) pulses at frequencies that correspond to trout heart rates in vivo at 7 degrees C, 14 degrees C and 21 degrees C. Additionally, [Ca(2+)](i) and I(Ca) were examined with square (SQ) pulses at slow (0.2 Hz) and physiologically relevant contraction frequencies. The amplitude of [Ca(2+)](i) decreased with increasing temperature for both SQ and AP pulses, which may contribute to the well-known negative inotropic effect of warm temperature on contractile strength in trout hearts. With SQ pulses, [Ca(2+)](i) decreased from 474+/-53 nmol l(-1) at 7 degrees C to 198+/-21 nmol l(-1) at 21 degrees C, while the decrease in [Ca(2+)](i) with AP pulses was from 234+/-49 nmol l(-1) to 79+/-12 nmol l(-1), respectively. Sarcolemmal Ca(2+) influx was increased slightly at cold temperatures with AP pulses (charge transfer was 0.27+/-0.04 pC pF(-1), 0.19+/-0.03 pC pF(-1) and 0.13+/-0.03 pC pF(-1) at 7 degrees C, 14 degrees C and 21 degrees C, respectively). At all temperatures, cells were better able to maintain diastolic Ca(2+) levels at physiological frequencies with AP pulses compared with 500 ms SQ pulses. We suggest that temperature-dependent modulation of the AP is important for cellular Ca(2+) regulation during temperature and frequency change in rainbow trout heart.

Action Potentials↗
PubMed1994

A further attenuated derivative of a cold-passaged temperature-sensitive mutant of human respiratory syncytial virus retains immunogenicity and protective efficacy against wild-type challenge in seronegative chimpanzees.

A cold-passage (cp), temperature-sensitive (ts) RSV mutant designated RSV cpts-248 (shut-off temperature 38 degrees C), which possesses host-range mutations acquired during 52 passages at low temperature in bovine tissue culture and a ts phenotype introduced by subsequent chemical mutagenesis, was found previously to be attenuated, immunogenic, and protective against wild-type challenge in seronegative chimpanzees. We sought to introduce additional attenuating mutations such as small-plaque (sp) and ts mutations into RSV cpts-248 by chemical mutagenesis with 5-fluorouracil with the intent of obtaining cpts-248 derivatives that are more attenuated in mice or chimpanzees and that are more genetically stable following replication in vivo. Ten mutants of RSV cpts-248 which had acquired a sp phenotype or a second ts mutation were generated by chemical mutagenesis. Five cpts-248 derivatives which had acquired mutations that specified a 36 degrees C shut-off temperature for plaque formation and one which had acquired only a sp phenotype were more restricted in replication in Balb/c mice than the cpts-248 parental strain. One mutant, designated RSV cpts-248/404 (shut-off temperature 36 degrees C), was 100 times more restricted in replication in the nasal turbinates of mice and 100 times more restricted in the nasopharynx of seronegative chimpanzees than its cpts-248 parent. The cpts-248/404 mutant was completely restricted in replication in the lower respiratory tract of chimpanzees even following direct intratracheal administration. The ts phenotype of the cpts-248/404 mutant was stable during replication in vivo in mice and chimpanzees.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1998

Inclement weather and the risk of hip fracture.

An association between inclement weather and hip fractures has been documented, but specific subgroups of the population at particular risk have not been identified. We obtained information that included hospitalization data on all hip fractures in Montreal from 1982 to 1992, and meteorologic data on the amount of snow, rain, and freezing rain and the temperature on each day of study. We used a cross-level design to examine the association between the rate of hip fractures and the meteorologic conditions on the day of the accident in both sexes and five age strata. There were a total of 18,455 hip fractures over the 4,018-day study period. We found a cyclical pattern in occurrence of hip fractures, with the peak occurring in mid-December among women and the first week of January among men. The pattern was less pronounced among women than men, with peak-to-trough ratios of 1.2 and 1.4, respectively. Days with lower temperatures, snow, and freezing rain were associated with increased rates of hip fracture. The meteorologic condition carrying the greatest risk was freezing rain. The association between inclement weather and hip fractures was stronger among younger persons, both women and men. After adjusting for meteorologic variables, there remained increases in winter of 5% among women and 12% among men. The residual effect of winter may be related to cold temperatures or due to an accumulation of ice and snow even on fine days. Other possible mechanisms to explain the residual effect of winter include slower reaction times and winter bone loss, both of which could affect indoor as well as outdoor falls.

Age Factors↗
PubMed2002

Physiological variation in insects: large-scale patterns and their implications.

In this paper we demonstrate how broad scale comparative physiology has an important role to play in informing a variety of assumptions made in macroecology. We do so by examining large-scale geographic variation in insect development, thermal tolerance and metabolic rate. From these studies, and those from the literature on insect water loss and thermoregulation, we show that there is often a bias to the geographic extent of available empirical data. Studies of cold hardiness are most usually undertaken at high latitudes, while investigations of upper thermal tolerances and water loss are most common in warm arid regions. Likewise, we demonstrate that much variation in insect physiological tolerances is partitioned at higher taxonomic levels, which has important implications for comparative physiology. Intriguingly, data on the full range of variables we review are available for only three species. We also show that, despite its importance, body size is regularly reported in only some kinds of investigations (metabolic rate, water loss rate), whereas in others (upper lethal temperature, cold hardiness, development) this variable is often ignored. In short, although large-scale comparative physiology can contribute considerable understanding to both physiology and ecology, there is much that remains to be done.

Animals↗
PubMed1989

Molecular and genetic organization of the suppressor of sable and minute (1) 1B region in Drosophila melanogaster.

Recessive mutations at the suppressor of sable [su(s)] locus in Drosophila melanogaster result in suppression of second site mutations caused by insertions of the mobile element 412. In order to determine whether su(s) mutations might have other phenotypes, a saturation mapping of the su(s) region was carried out. The screen yielded 76 mutations that comprise ten genetic complementation groups ordered distal to proximal as follows: l(1)1Bh, l(1)1Bi, M(1)1B, su(s), l(1)1Bk, l(1)1Ca, mul, tw, l(1)lDa and brc. Twenty-three of the mutations are su(s) alleles, and all are suppressors of the 412-insertion-caused v1 allele. Although the screen could have detected su(s) mutations causing sex-specific dominant lethality or sterility as well as all types of recessive lethality or sterility, the only other phenotype observed was male sterility that is enhanced by cold temperature. This type of sterility is exhibited only by alleles induced by base-substitution-causing mutagens. Genetic functions of the poly(A+) messages transcribed from the su(s) microregion were identified by the reintroduction of cloned sequences into embryos by P element transformation. su(s) function has been attributed to a 5-kb message. The segment of DNA encoding only this 5-kb message rescues both the suppression and cold-sensitive male sterility phenotypes of su(s). Minute (1) 1B has been provisionally identified as encoding a 3.5-kb message; lethal (1)1Bi encodes a 1-kb message; and lethal (1)1Bk encodes a 4-kb message. The possible functions of su(s) and M(1)1B are discussed.

Alleles↗
PubMed2005

Increased sensitivity to thermal pain and reduced subcutaneous lidocaine efficacy in redheads.

BACKGROUND: Anesthetic requirement in redheads is exaggerated, suggesting that redheads may be especially sensitive to pain. Therefore, the authors tested the hypotheses that women with natural red hair are more sensitive to pain and that redheads are resistant to topical and subcutaneous lidocaine. METHODS: The authors evaluated pain sensitivity in red-haired (n = 30) or dark-haired (n = 30) women by determining the electrical current perception threshold, pain perception, and maximum pain tolerance with a Neurometer CPT/C (Neurotron, Inc., Baltimore, MD). They evaluated the analogous warm and cold temperature thresholds with the TSA-II Neurosensory Analyzer (Medoc Ltd., Minneapolis, MN). Volunteers were tested with both devices at baseline and with the Neurometer after 1-h exposure to 4% liposomal lidocaine and after subcutaneous injection of 1% lidocaine. Data are presented as medians (interquartile ranges). RESULTS: Current perception, pain perception, and pain tolerance thresholds were similar in the red-haired and dark-haired women at 2,000, 250, and 5 Hz. In contrast, redheads were more sensitive to cold pain perception (22.6 [15.1-26.1] vs. 12.6 [0-20] degrees C; P = 0.004), cold pain tolerance (6.0 [0-9.7] vs. 0.0 [0.0-2.0] degrees C; P = 0.001), and heat pain (46.3 [45.7-47.5] vs. 47.7 [46.6-48.7] degrees C; P = 0.009). Subcutaneous lidocaine was significantly less effective in redheads (e.g., pain tolerance threshold at 2,000-Hz stimulation in redheads was 11.0 [8.5-16.5] vs. > 20.0 (14.5 to > 20) mA in others; P = 0.005). CONCLUSION: Red hair is the phenotype for mutations of the melanocortin-1 receptor. Results indicate that redheads are more sensitive to thermal pain and are resistant to the analgesic effects of subcutaneous lidocaine. Mutations of the melanocortin-1 receptor, or a consequence thereof, thus modulate pain sensitivity.

Adult↗
PubMed2003

[Multiplication technique of rice T(P) GMS line with double low critical temperature values using cold water irrigation].

In this paper, cold-water irrigation multiplication technique was used to solve the difficulty of multiplying rice TGMS line 96-5-2S(Oryza sative L.) with double low critical temperature values under natural air temperature condition. The results indicated that irrigating rice TGMS line 96-5-2S with different temperature underground cold water from the stage of pistil and stamen primordia differentiation to the stage of pollen filling for 15 days, and keeping the water depth 18-22 cm, the seed set rate of 96-5-2S decreased with increasing irrigating water temperature. When the average temperature of irrigation water was 18.5-19.8 degrees C, the seed set rate ranged from 40.5% to 57.6%, and the yield ranged from 3.30 t.hm-2 to 4.35 t.hm-2. While the temperature was 20.5-21.3 degrees C, the seed set rate and yield sharply decreased to 2.5-10.4% and 0.21-0.90 t.hm-2, respectively. When the average temperature was 22.3-23.5 degrees C, both the seed set rate and yield were zero. Under the same irrigation water temperature (average 19.8 degrees C) and the same irrigating period (phase IV to phase VII), the seed set rate and yield of 96-5-2S with deep water irrigation (18-22 cm) was very significantly higher than those of 96-5-2S with shallow water irrigation (7-10 cm). Under the conditions of same irrigation water temperature (average 19.8 degrees C) and same water depth (18-22 cm) but different irrigating periods (15 days from phase IV to phase VII, 20 days from phase III to phase VII, and 25 days from phase II to phase VII), the difference of seed set rate and yield of 96-5-2S between 15-day treatment and 20-25-day treatment was not significantly different. It is confident that 96-5-2S could multiply with underground cold water irrigation. The main technique index was that irrigating water temperature should be 18-20 degrees C, irrigating period should be from phase IV to phase VII, and irrigating water depth should be 18-22 cm.

Agriculture↗
PubMed1984

Effect of temperature on the occluding junctions of monolayers of epithelioid cells (MDCK).

In previous works it was demonstrated that the monolayer of MDCK cells behaves as a leaky epithelium where the electrical resistance across reflects the sealing capacity of the occluding junction. In the present work we study whether this sealing capacity can be modified by temperature and whether this is accompanied by changes in the structure of the occluding junction. Monolayers were prepared on disks of nylon cloth coated with collagen and mounted as a flat sheet between two Lucite chambers. The changes in resistance elicited by temperature were large (306% between 3 and 37 degrees C), fast (less than 2 sec), and reversible. An Arrhenius plot of conductance versus the inverse of temperature shows a broken curve (between 22 and 31 degrees C), and the activation energies calculated (3.2 and 4.0 kcal X mol-1) fall within the expected values for processes of simple diffusion. The morphology of the occluding junction was evaluated in freeze-fracture replicas by counting the number of strands and the width of the band occupied by the junction every 133 nm. In spite of the change by 306% of the electrical resistance and the phase transition, we were unable to detect any appreciable modification of the morphology of the occluding junction. Since the freeze-fracture replicas also show a density of intramembrane particles (IMP) different in the apical from that in the basolateral regions of the plasma membrane, as well as differences between face E and face P, we also investigated whether this is modified by temperature. Cold increases the population of IMP, but does not affect their polarization with the incubation time it takes to elicit changes in electrical resistance.

Animals↗
PubMed1981

Critical appraisal of complement dependent microlymphocytotoxicity assay for detecting donor-specific alloantibody pretransplant--importance of indirect immunofluorescence as a superior alternative.

The ability of complement-dependent microlymphocytotoxicity assay (CdL) to detect and discriminate between the various types of donor-specific alloantibodies was reevaluated. Data obtained with the CdL assay on purified B and T lymphocytes at warm and cold temperatures was compared to other modes of antibody-detection, i.e., indirect immunofluorescence (IF) and the noncomplement-dependent antibody-dependent cellular cytotoxicity (ADCC). Additionally, the significance of antibodies as detected by CdL and IF was ascertained by correlating with kidney transplant outcome. It became apparent that the CdL assay identified weakly reactive HLA-ABC alloantibodies as being B cell specific. Such weakly reactive HLA-ABC antibodies were also not appreciated in the presence of the cold reactive IgM antibody. Accelerated rejections were the rule in the presence of weakly reactive HLA-ABC alloantibodies indicating that their detection was highly important. The IF assay could discriminate between the antibody class, could detect weakly reactive HLA-ABC alloantibodies, and could detect noncomplement fixing antibodies (ADCC). Further, use of IF prevented us from unnecessarily denying transplants to certain recipients when a positive CdL assay resulted from an IgM antibody or poor cell viability.

Antibody Specificity↗
PubMed1991

Chilling-Induced Inactivation and Its Recovery of Tonoplast H-ATPase in Mung Bean Cell Suspension Cultures.

The processes involved in adaptation to cold temperature were examined by growing suspension cultured cells of mung bean (Vigna radiata [L.] Wilczek) at 2 degrees C for various periods of time and assaying the activities of various membrane-bound enzymes in vitro. The tonoplast H(+)-ATPase activity and the ATP-proton transport extracted from cells incubated at 2 degrees C declined rapidly and reached a minimum level after 10 hours. The inactivation was reversible within 24 hours of chilling. The recovery of the cold-inactivated H(+)-ATPase was found to proceed in two steps, a faster recovery of ATP hydrolysis activity and a slower recovery of the proton transport. The recovery was markedly inhibited by the presence of azide, but not affected by 0.578 millimolar cycloheximide. This suggested the involvement of an energy process that had no requirement for de novo synthesis of protein. The cold-induced inactivation of the H(+)-ATPase may be due to a structural alteration of the enzyme. The slower recovery of proton transport relative to ATP hydrolysis during warming suggests that the protogenic domains in the enzyme may be affected differently by chilling.

Journal Article↗
PubMed2003

Tissue- and stressor-specific differential expression of two hsc70 genes in carp.

Two genes expressing 70 kDa heat shock proteins were identified in Cyprinus carpio. The sequence similarities and the intron-interrupted structure of the coding regions indicate that carp Hsc70-1 and Hsc70-2 belong to the Hsp70 cognate subfamily. The expressions of the two hsc70 genes were followed by semi-quantitative RT-PCR. Both genes are expressed under unstressed conditions in a characteristic tissue-specific manner. Inducibility of the response to elevated temperature, cold shock, and Cd treatment was investigated in the liver and muscle, in whole-animal experiments. Both genes were insensitive to or only weakly induced by the stressors, with two exceptions: Cd treatment resulted in an 11-13-fold enhanced induction of hsc70-1 in the liver and cold shock enhanced induction of hsc70-2 in the muscle by 7.5-10-fold.

Amino Acid Sequence↗
PubMed1975

Observations on the mechanical precipitation of oxy Hb S and other mutants.

Oxyhemoglobin S exhibits greater mechanical instability than oxyhemoglobin A. The rate of precipitation of Hb S when agitated by vortexing depends upon the geometry of the tube, the volume of the hemoglobin solution, and the concentration of hemoglobin. The rate of precipitation is inversely related to concentration. Precipitation is inhibited by temperatures near 4 degrees C and alkylureas whose protective capacity is approximately proportional to the carbon chain length of the alkyl group. Blocking the beta93 -SH group with parahydroxymercuribenzoate has only a small enhancing effect on the precipitation rate. Other mutants such as Hb Gun Hill, Leiden, (both heat unstable), and C-HARLEM are also unstable. In the case of C-HARLEM, the precipitation rate is greater than that for Hb S. The heat-unstable mutants are not as well protected by cold temperatures or alkyl ureas. D2O has only a minor stabilizing effect on hemoglobin S, but NaCl and related salts markedly enhance precipitation at concentrations of 0.5 M. It is concluded that mechanical instability of oxyhemoglobins is a multifactorial process involving surface denaturation, pH, ionic strength, hydrophobic interactions, protein conformation, and primary protein structure. This phenomenon will require more extensive investigation.

Carbon Radioisotopes↗
PubMed2003

Swimming of pregnant rats at different water temperatures.

We studied the chronic effect of exercise during water immersion, associated with thermal stress (water temperature at 22, 35 and 40 degrees C) at an intensity of 80% of maximal work load supported in pregnant rats (P) and non-pregnant female rats (NP). P and NP were subdivided into three subgroups according to water temperature during exercise (P22 and NP22; P35 and NP35; P40 and NP40). The animals were submitted to daily swimming sessions of 10-15 min, for 19 days of pregnancy (P) or experimental conditions (NP). Plasma concentration of triglycerides, cholesterol, glucose, total protein, albumin and corticosterone were determined 24 h after the last exercise session. Weight gain and rectal temperature pre- and post-swimming session were also determined. The offspring were examined just after caesarian section on the 20th day of pregnancy to check weight, length and litter size. Pregnant rats showed an increase of triglycerides, reduction of glycemia, total protein and albumin and cholesterol (at 35 degrees C) when compared to non-pregnant animals. Such effects probably lead to an adequate delivery of substrate to the fetus and prepare the mother for lactation. Daily thermal stress did not modify metabolic responses to exercise in pregnant rats. Results also show a deleterious effect on offspring when the mother is exposed daily to extreme temperatures during swimming. These results suggest that water temperature (cold and hot) in swimming have to be considered to avoid damage in fetal development.

Animals↗
PubMed2005

Cryo-injury and biopreservation.

Mammalian cells appear to be naturally tolerant to cold temperatures, but the formation of ice when cells are cooled leads to a variety of damaging effects. The study of cryo-injury, therefore, becomes the study of when and how ice is formed both inside and outside the cell during cooling. Protectant chemicals are used to control or prevent ice formation in many preservation protocols, but these chemical themselves tend to be damaging. Cooling and warming rates also strongly affect the amount and location of ice that is formed. Through careful modification of these parameters successful cold preservation techniques for many cell types have been developed, but there are many more cell types that have defied preservation techniques, and the extension of cell-based techniques to tissues and whole organs has been very limited. There are many aspects to the damaging effects of ice in cells that are still poorly understood. In this brief article we review our current understanding of cellular injury and highlight the aspects of cellular injury during cryopreservation that are still poorly understood.

Cell Membrane↗
PubMed2003

[Rituximab in cold agglutinin disease].

PURPOSE: Cold agglutinin disease is a chronic auto-immune hemolytic anemia related to a lymphoproliferative disorder with a degenerative potential and no codified treatment. This rare affection is related to the production of anti-erythrocytes immunoglobulins M. They are responsible of hemolytic crises sometimes severe and vascular acrosyndrom when submitted to cold temperature. Before rituximab, a monoclonal antibody targeted against the B lymphocyte CD20 antigen, no treatment was really efficient. METHODS: We present 5 patients who have been treated with 4 weekly rituximab perfusions, and then we proceed to a review of the literature concerning the other 23 similar cases. RESULTS: With a good tolerance, the treatment allowed a remission in all the cases (4 partial, 1 complete). Among the 23 observations published, the rate of answer was 21/23 (of which 14 gave completes). CONCLUSION: Rituximab is an alternative treatment of cold agglutinin disease.

Aged↗
PubMed2006

Stored human septal chondrocyte viability analyzed by confocal microscopy.

OBJECTIVES: To analyze the effects of prolonged storage time, at warm and cold temperatures, on the viability of human nasal septal chondrocytes and to understand the implications for tissue engineering of septal cartilage. DESIGN: Basic science. SUBJECTS: Septal cartilage was obtained from 10 patients and placed in bacteriostatic isotonic sodium chloride solution. Four specimens were kept at 23 degrees C, and 4 were kept at 4 degrees C. The viability of the chondrocytes within the cartilage was assessed using confocal laser scanning microscopy every 5 days. The 2 other specimens were assessed for viability on the day of harvest. RESULTS: Viability on the day of harvest was 96%, implying minimal cell death from surgical trauma. After 1 week, cell survival in all specimens was essentially unchanged from the day of harvest. At 23 degrees C, the majority (54%) of cells were alive after 20 days. At 4 degrees C, 70% of cells survived 1 month and 38% were alive at 2 months. Qualitatively, chondrocytes died in a topographically uniform distribution in warm specimens, whereas cold specimens displayed a more irregular pattern of cell death. CONCLUSION: Septal chondrocytes remain viable for prolonged periods when stored in simple bacteriostatic isotonic sodium chloride solution, and such survival is enhanced by cold storage.

Adult↗