Correlation of electrical impedance and temperature in tissue during freezing.

Experiments were performed correlating tissue temperature and tissue impedance in the course of freezing canine skin and palate. Tissue impedance rose gradually to high levels as the tissue froze. Tissue temperature of ?26 ° to ?30 °C corresponded closely to tissue impedance of 1 MΩ. Tissue impedance of 5 to 10 MΩ corresponded closely to temperatures of ?40 °C and colder. These observations indicated that the measurement of tissue impedance was related to tissue temperature and suggested that either or both could be used to predict tissue destruction in cryosurgery.     

Critical temperature for skin necrosis in experimental cryosurgery

To investigate the minimal lethal freezing temperature required to produce skin necrosis in dogs, multiple skin sites were frozen with cryosurgical equipment. Tissue temperatures were recorded from thermocouple sites placed at diverse distances, usually 5 mm from the edge of the freezing probe. In single freezing cycles of about 3 min duration, tissue temperatures in the range of 0 to ?60 °C were produced. Punch biopsies of the skin at the thermocouple sites 3 days after freezing injury provided tissues for estimation of viability by histologic examination.The histologic findings permitted classification of the biopsy tissue into three groups, that is, viable, borderline, or necrotic. When classified as borderline, the division between the necrotic and viable tissue was evident on the histologic slide. The viable specimens were scattered through the 0 to ?35 °C range. All specimens frozen to ?10 °C or warmer were viable. In biopsies classified as borderline, the range of viability extended from ?11 ° to ?50 °C. The necrotic biopsies covered a range of ?14 ° to ?50 °C. Cell death was certain at temperatures colder than ?50 °C. The data showed cryosurgical freezing conditions produced a range of temperatures in which viability or death of tissue may occur and that the ranges of viability and necrosis overlapped to a great extent.The wide range of temperatures at which cells were viable shows the need to achieve tissue temperatures in the range of ?50 °C in the cryosurgical treatment of cancer.     

Determination of cryothermal injury thresholds in tissues impacted by cardiac cryoablation

Despite widespread clinical use of cryoablation, there remain questions regarding dosing and treatment times which may affect efficacy and collateral injury. Dosing and treatment times are directly related to the degree of cooling necessary for effective lesion formation. Human and swine atrial, ventricular, and lung tissues were ablated using two cryoablation systems with concurrent infrared thermography. Post freeze-thaw samples were cultured and stained to differentiate viable and non-viable tissue. Matlab code correlated viability staining to applied freeze-thaw thermal cycles, to determine injury thresholds. Tissue regions were classified as live, injured, or dead based upon staining intensity at the lesion margin. Injury begins at rates of ∼10 °C/min to 0 °C, with non-viable tissue requiring cooling rates close to 100 °C/min to ∼ −22 °C for swine and significantly greater cooling to −26 °C for human tissue (p = 0.041). At similar rates, lung tissue injury began at 0 °C, with human tissue requiring significantly less cooling, to ∼ −15 °C for complete necrosis and −26 °C for swine (p = 0.024). Data suggest that there are no significant differences between swine and human myocardial response, but there may be differences between swine and human lung cryothermal tolerance.     

Bone destruction by direct cryoapplication: A temperature study in rabbits

The cortical temperature as well as the temperature in the marrow cavity of rabbit mandibular bone was measured at various distances from the cryoapplication point. The temperatures reached were correlated to previous histological and microcirculatory investigations. It was established that a bone tissue mean temperature of at least ?50 °C should be attained in order to secure total and homogeneous bone destruction.     

Cold hardiness in various organs and tissues of Rhododendron species and the supercooling ability of flower buds as the most susceptible organ

The freezing resistance of various organs and tissues was determined in 24 Rhododendron species (mainly Subgenus Tsutsutsi) having different ecological distributions. The order of hardiness for organ or tissue is as follows: leaf bud > wood ≧ bark > flower bud, and the flower bud is characterized as the most cold-susceptible organ. The relationship of killing temperature (KT) to northern distribution was the most significant in leaf buds compared to other organs and tissues. KTs of leaf buds for the most hardy species were ?45 °C (or below) and those for the most tender species were about ?23 °C, while KTs of flower buds were about ?28 °C for the former and ?16 °C for the latter. Although KTs of flower buds native to southwestern Japan were well correlated with the exothermic temperature distribution (ETD) of florets, those in the more northern species were generally lower than ETDs. The supercooling ability of flower buds appears to be sufficient to avoid the freezing stress since the extreme minimum temperature (EMT) at the northern limit of natural distribution for each tree species examined was not lower than the KT and ETD of the flower buds.     

Determination of resistance to low temperatures of winter buds on lateral shoot present in Karaerik (<Emphasis Type="Italic">Vitis vinifera</Emphasis> L.) grape cultivar

This study aims to determine the low temperature resistance of dormant buds at nodes with or without lateral shoots of Karaerik grape cultivar, and explain the relationship between the resistance and biochemical parameters in this grape cultivar. In this study, the mean values of high temperature exotherms (HTEs), low temperature exotherms (LTEs), water, reducing sugar, total soluble protein contents and antioxidant enzyme activities of dormant buds taken from nodes with or without lateral shoots were determined. The experiment has been found that buds in nodes with lateral shoots showed HTE and LTE at higher temperatures (HTE average ?6.7 °C and LTE average ?8.3 °C) than buds (HTE average ?7.9 °C and LTE average ?11.5 °C) in nodes without lateral shoots; therefore, buds in nodes with lateral shoots had less tolerance to low temperature. Additionally, lower sugar (average 41.05 mg g^?1), protein (average 1.61 mg g^?1), superoxide dismutase (average 425.27 EU g^?1 tissue), peroxidase (average 2516.1 EU g^?1 tissue) and polyphenol oxidase (average 7283.1 EU g^?1 tissue) were determined for buds taken from nodes with lateral shoots. Due to the fact that dormant buds taken from nodes with lateral shoots decreased the resistance to low temperatures, this research suggests that these lateral shoots should be excised with the summer pruning at the regions, where low temperatures caused the damages.     

Magnetic resonance imaging (MRI) as a method for determination of freezing injury in strawberry crowns

In an experiment with controlled freezing, strawberry plants were exposed to 0, ?8, ?12, ?16 and ?20°C at a freeze and thaw rate of 2 °C/hour in March/April 1996. Crowns from the cultivar ‘Korona’ were examined using magnetic resonance imaging (MRI), showing a gradual increase of signal intensity from the centre of the crowns, as a result of the temperature drop, which might be caused by lipids. The increase in signal intensity was in accordance with the tissue browning of crowns, which increased substantially when the temperature dropped below ?12 °C. A similar reaction was shown in a field experiment comparing wintercovered and not wintercovered strawberry plants. The plants which had been exposed to temperatures between ?10 and ?16 °C were severely injured. This demonstrates that MRI has a potential as an objective method to determine freeze injury in the field, by «calibrating» the MRI instrument to freezing profiles in controlled experiments.     

Survival of tissue culture cells frozen by a two-step procedure to -196 degrees C. II. Warming rate and concentration of dimethyl sulphoxide.

Chinese hamster tissue culture cells in dimethyl sulphoxide (5%) required a lower holding temperature (?35 °C) for optimal survival on slow warming from ?196 °C using a two-step cooling schedule, compared with that required (?25 °C) when warming was rapid. A lower concentration of dimethyl sulphoxide (1%) did not affect the “protection” against damage on cooling from the holding temperature to ?196 °C and thawing. The results suggest that protective agents allow cells to be cooled initially to the holding temperature and minimize damage at the holding temperature. Damage following subsequent cooling and thawing may thus occur mainly as dilution shock on rewarming. This can be minimized by allowing the cells to shrink at the holding temperature.     

Effects of hot water treatments and storage temperatures on the ripening and the use of electrical impedance as an index for assessing post-harvest changes in mango fruits

The effects of hot water treatment and storage temperature (4°C, 13°C or 22°C) on the quality and impedance of outer and inner mesocarp of mango were assessed in two experiments during storage, impedance being a potential non‐destructive measure of tissue damage following heat treatment. Fruits were subjected to equivalent heat units at 36.5°C for 60 min plus 46.5°C for 43 min or 46.5°C for 90 min by hot water treatments (hwt) on the assumption of cumulative heat effects and a base temperature of 12–13°C. Fruit reflectance decreased whereas chroma and hue angle increased over storage time and also with increase in storage temperature. The yellow colour increased with a rise in storage temperature in hot water treated mangoes. Soluble solids content of mangoes held at 22°C was highest at 5 days of storage but decreased subsequently over storage time. Impedance of all fruits decreased with increase in frequency, storage temperature and time in store. The impedance of hwt mangoes was lower than that of non‐hwt fruits 8 h after immersion, but recovered almost to control levels on day 5 at 4°C or 13°C, but decreased gradually after 5 days at 13°C. Impedance of all mangoes stored at 22°C decreased continuously during storage. Impedance was higher in the inner mesocarp than outer pulp. Impedance of hwt fruits was poorly correlated with soluble solid content and chroma but well correlated with reflectance of fruit pulp at 22°C. Changes in impedance of mangoes are discussed in relation to physiological and biochemical changes that occur during heat treatment and storage.     

Survival of tissue culture cells frozen by a two-step procedure to -196 degrees C. I. Holding temperature and time.

A two-step freezing procedure has been examined in order to separate some of the causes of damage following freezing and thawing. Different holding temperatures and times have been studied during the freezing of Chinese hamster tissue culture cells in dimethyl sulphoxide (5%, $\text{v}\text{v}$). Damage following rapid cooling to, time at, and thawing from different holding temperatures was found to increase at lower holding temperatures and at longer times. Damage on subsequent cooling from the holding temperature to ?196 °C and thawing was found to diminish at lower holding temperatures and longer times. The net result was that optimal survival from ?196 °C was obtained after 10 min at ?25 °C. Protection against the second step of cooling to ?196 °C was acquired at the holding temperature itself and was absent at ?15 °C without freezing.It seems that this technique will allow the different phases of freezing injury to be separated. These phases may include thermal shock to the holding temperature, hypertonic damage at the holding temperature and dilution shock on thawing from ?196 °C.     

Auxin and cytokinin levels in selected and temperature-induced morphologically distinct tissue lines of tobacco crown gall tumors

Two morphologically distinct tissue culture lines were selected from a tobacco (Nicotiana tabacum L. ‘Wisconsin 38’) crown gall tumor: (1) a green teratomous line producing numerous abnormal shoots, designated leafy; and (2) a white, hard, spherical tissue, designated white. These were originally isolated at 27°C, but temperature changes were also found to control these morphologies, with 33°C favoring the development of the leafy form and 21°C favoring the white form. The higher temperature was also correlated with a decrease in the endogenous levels of both auxin and cytokinin, whereas the lower temperature was correlated with an increase in the levels of these growth regulators. There was no significant difference, however, in the auxin and cytokinin levels in the two forms maintained at 27°C, suggesting that the basis for morphological changes at this temperature resides either in very subtle differences in auxin and cytokinin or in factors other than these two growth regulators.     

Effects of temperature on the growth and microstructure formation of cuttlebone from cuttlefish Sepia pharaonis

ABSTRACT

This study investigated the effects of three temperatures (20°C, 27°C, and 31°C) on the physiological performance (survival and growth) and cuttlebone micromorphological features (chamber number, chamber height and lamellae number) of cuttlefish Sepia pharaonis. We examined gross morphological characteristics of the internal calcareous cuttlebone to determine whether lamellar matrix was impacted by temperature. Juvenile survival was significantly affected by temperature (χ²?=?54.580, df?=?2, P?<?0.001). Cuttlebone weight, length and width were also positively correlated with temperature. Scanning electron microscopy revealed that a single chamber structure consists of septa, lamellae and pillars. At 20°C the chamber number of 89.0?±?10.8 was significantly higher than at 27°C with 44.8?±?3.6 or 31°C with 47.5?±?4.3 (Kruskal–Wallis [KW], χ^2?=?26.391, df?=?2, P?=?0.0001), whilst chamber height was lower at 20°C (KW χ^2?=?27.842, df?=?2, P?=?0.0001). Moreover, lamellae number varied among the treatments (KW χ^2?=?22.411, df?=?2, P?=?0.0002). Lamellae numbers at 20°C, 27°C and 31°C were 3–6, 6–9 and 5–8, respectively. The results indicated that the intrinsic lamellar matrix structure was significantly affected by temperature and that this effect may be used in cuttlebone growth studies.     

Freeze-dried plasma proteins are stable at room temperature for at least 1 year

Thirty human EDTA plasma samples from male and female subjects ranging in age from 24 to 74 years were collected on ice, processed ice cold and stored frozen at ?80 °C, in liquid nitrogen (LN2), or freeze dried and stored at room temperature in a desiccator (FDRT) or freeze dried and stored at ?20 °C for 1 year (FD-20). In a separate experiment, EDTA plasma samples were collected onto ice, processed ice cold and maintained on ice ± protease inhibitors versus incubated at room temperature for up to 96 h. Random and independent sampling by liquid chromatography and tandem mass spectrometry (LC–ESI–MS/MS), as correlated by the MASCOT, OMSSA, X!TANDEM and SEQUEST algorithms, showed that tryptic peptides from complement component 4B (C4B) were rapidly released in plasma at room temperature. Random sampling by LC–ESI–MS/MS showed that peptides from C4B were undetectable on ice, but peptides were cleaved from the mature C4B protein including NGFKSHALQLNNR within as little as 1 h at room temperature. The frequency and intensity of precursors within ± 3 m/z of the C4B peptide NGFKSHALQLNNR was confirmed by automated targeted analysis where the precursors from MS/MS spectra that correlated to the target sequence were analyzed in SQL/R. The C4B preproprotein was processed at the N terminus to release the mature chain that was cleaved on the carboxyl side of the isoprene C2 domain within a polar C terminal sequence of the mature C4B protein, to reveal the thioester reaction site, consistent with LC–ESI–MS/MS and Western blot. Random sampling showed that proteolytic peptides from complement component C4B were rarely observed with long term storage at ? 80 °C in a freezer or in liquid nitrogen (LN2), freeze drying with storage at ? 20 °C (FD-20 °C) or freeze drying and storage at room temperature (FDRT). Plasma samples maintained at room temperature (RT) showed at least 10-fold to 100-fold greater frequency of peptide correlation to C4B and measured peptide intensity compared to samples on ice for up to 72 h or stored at ? 80 °C, LN2, FDRT or FD-20 °C for up to a year.     

Seasonal changes in entrainment cues for the circadian rhythm of the supratidal amphipod Talorchestia longicornis

The supratidal amphipod Talorchestia longicornis Say has a circadian rhythm in activity, in which it is active on the substrate surface at night and inactive in burrows during the day. The present study determined: (1) the circadian rhythms in individual versus groups of amphipods; (2) the range of temperature cycles that entrain the circadian rhythm; (3) entrainment by high-temperature cycles versus light?:?dark cycles, and (4) seasonal substrate temperature cycles. The circadian rhythm was determined by monitoring temporal changes in surface activity using a video system. Individual and groups of amphipods have similar circadian rhythms. Entrainment occurred only to temperature cycles that included temperatures below 20°C (10–20, 15–20, 17–19, 15–25°C) but not to temperatures above 20°C (20–25, 20–30°C), and required only a 2°C temperature cycle (17–19°C). Diel substrate temperatures were above 20°C in the summer and below 20°C during the winter. Upon simultaneous exposure to a diel high-temperature cycle (20–30°C) and a light?:?dark cycle phased differently, amphipods entrained to the light?:?dark cycle. Past studies found that a temperature cycle below 20°C overrode the light?:?dark cycle for entrainment. The functional significance of this change in entrainment cues may be that while buried during the winter, the activity rhythm remains in phase with the day?:?night cycle by the substrate temperature cycles. During the summer, T. longicornis switches to the light?:?dark cycle for entrainment, perhaps as a mechanism to phase activity precisely to the short summer nights.     

Survival,haemolymph osmolality and tissue water of Penaeus chinensis juveniles acclimated to different salinity and temperature levels

Survival, growth, haemolymph osmolality and tissue water of Penaeus chinensis (Osbeck) juveniles (0.11 ± 0.04 g) were investigated, after they were acclimated to 10, 20, 30 and 40 ppt from 33 ppt for 14 days at 24°C, and then acclimated to 12, 18, 24 and 30°C at each salinity for 14 days. The survival of shrimp was the lowest at 10 ppt and 12°C. Growth of shrimp increased with increased temperature in the range 12–24°C, with no significant difference among four salinity levels at 18, 24 and 30°C. Haemolymph osmolality increased with increased salinity, and decreased with increased temperature. The isosmotic point computed from the linear relationship between haemolymph osmolality and medium osmolality was 664, 632, 629 and 602 mOsm/kg which is equivalent to 25.2, 24.1, 24.0 and 23.1 ppt at 12, 18, 24 and 30°C, respectively. Tissue water decreased with increased medium osmolality and haemolymph osmolality. The slope obtained from the relationship between haemolymph osmolality and medium osmolality indicated that there is an impairment of osmoregulatory ability for the P. chinensis juveniles at 12°C.     

Critically reduced frost resistance of Picea abies during sprouting could be linked to cytological changes

Frost resistance of sprouting Picea abies shoots is insufficient for survival of naturally occurring late frosts. The cellular changes during sprouting appeared to be responsible for frost damage as frost events that damaged sprouting shoots did not damage older needles and stems. Whilst resting buds showed initial frost damage at ?15.0°C, 20 days later, current year’s growth was damaged at ?5.6°C. The decrease in frost resistance in sprouting shoots of P. abies was accompanied by a significant reduction of the cellular solute concentration, indicated by much less negative Ψ_oSAT values (increase from ?2.8 to ?1.2 MPa). ψ_oSAT decreased again after the final cell volume was reached and cell wall thickening began. After bud break, ice nucleation temperature increased from ?4.7°C to ?1.5°C. This increase was probably caused by the loss of bud scales, the onset of expansion growth of the central cylinder and the development of vascular tissue permitting the spread of ice from the stem into the growing needles. The onset of mesophyll cell wall thickening coincided with the lowest frost resistances. Cell wall thickening caused an increase in the modulus of elasticity, ε, indicating a decrease in tissue elasticity and after that frost resistance increased again. Metabolic and cytological changes that evidently leave little leeway for frost hardening are responsible for the low frost resistance in current year’s growth of P. abies. This low frost resistance will be significant in the future as the risk of frost damage due to earlier bud break is anticipated to even further increase.     

White muscle 20S proteasome activity is negatively correlated to growth rate at low temperature in the spotted wolffish Anarhichas minor

The effect of temperature and mass on specific growth rate (G) was examined in spotted wolffish Anarhichas minor of different size classes (ranging from 60 to 1500 g) acclimated at different temperatures (4, 8 and 12° C). The relationship between G and 20S proteasome activity in heart ventricle, liver and white muscle tissue was then assessed in fish acclimated at 4 and 12° C to determine if protein degradation via the proteasome pathway could be imposing a limitation on somatic growth. Cardiac 20S proteasome activity was not affected by acclimation temperature nor fish mass and had no correlation with G. Hepatic 20S proteasome activity was higher at 12° C but did not show any relationship with G. Partial correlation analysis showed that white muscle 20S proteasome activity was negatively correlated to G (partial Pearson's r = ?0·609) but only at cold acclimation temperature (4° C). It is suggested that acclimation to cold temperature involves compensation of the mitochondrial oxidative capacity which would in turn lead to increased production of oxidatively damaged proteins that are degraded by the proteasome pathway and ultimately negatively affects G at cold temperature.     

Temperatures in Pigs During 3 T MRI Temperatures,Heart Rates,and Breathing Rates of Pigs During RF Power Deposition in a 3 T (128 MHz) Body Coil

Exposure to radiofrequency (RF) power deposition during magnetic resonance imaging (MRI) induces elevated body‐tissue temperatures and may cause changes in heart and breathing rates, disturbing thermoregulation. Eleven temperature sensors were placed in muscle tissue and one sensor in the rectum (measured in 10 cm depth) of 20 free‐breathing anesthetized pigs to verify temperature curves during RF exposure. Tissue temperatures and heart and breathing rates were measured before, during, and after RF exposure. Pigs were placed into a 60‐cm diameter whole‐body resonator of a 3 T MRI system. Nineteen anesthetized pigs were divided into four RF exposure groups: sham (0 W/kg), low‐exposure (2.7 W/kg, mean exposure time 56 min), moderate‐exposure (4.8 W/kg, mean exposure time 31 min), and high‐exposure (4.4 W/kg, mean exposure time 61 min). One pig was exposed to a whole‐body specific absorption rate (wbSAR) of 11.4 W/kg (extreme‐exposure). Hotspot temperatures, measured by sensor 2, increased by mean 5.0 ± 0.9°C, min 3.9; max 6.3 (low), 7.0 ± 2.3°C, min 4.6; max 9.9 (moderate), and 9.2 ± 4.4°C, min 6.1, max 17.9 (high) compared with 0.3 ± 0.3°C in the sham‐exposure group (min 0.1, max 0.6). Four time‐temperature curves were identified: sinusoidal, parabolic, plateau, and linear. These curve shapes did not correlate with RF intensity, rectal temperature, breathing rate, or heart rate. In all pigs, rectal temperatures increased (2.1 ± 0.9°C) during and even after RF exposure, while hotspot temperatures decreased after exposure. When rectal temperature increased by 1°C, hotspot temperature increased up to 42.8°C within 37 min (low‐exposure) or up to 43.8°C within 24 min (high‐exposure). Global wbSAR did not correlate with maximum hotspot. Bioelectromagnetics. 2021;42:37–50. © 2020 The Authors. Bioelectromagnetics published by Wiley Periodicals LLC on behalf of Bioelectromagnetics Society     

Variations in myocardial CPK and Na+-K+ ATPase following long-term freezing.

The activity of the soluble enzyme CPK and the membrane bound enzyme Na⁺-K⁺ ATPase as a function of storage temperature, time of storage and cryoprotectant type and concentration in canine myocardial tissue was invesigated. Activity of CPK is well preserved at ?196 °C and ?79 °C and falls off during one month storage at ?40 °, ?20 °, and 0 °C. Na⁺-K⁺ ATPase demonstrates a greater liability. After an initial cryoprotectant “activation,” activity drops. In all cases, however, addition of the cryoprotectant preserved activity better than in samples stored only in buffer.     

Temperature effects on growing, feeding, and swimming energetics in the Patagonian blennie Eleginops maclovinus (Pisces: Perciformes)

The Patagonian blennie Eleginops maclovinus is a coastal and estuarine species, important in recreational and commercial fisheries, and with aquaculture potential. This study assessed the effect of temperature on feeding and the allocation of energy in growth and swimming in a sub-Antarctic population. For growth experiments, two groups of 8 juveniles were reared at 4 and 10?°C (corresponding to winter and summer habitat temperatures, respectively) for 3?months. Swimming experiments were conducted at 5 and 10?°C, measuring the oxygen consumption before and after forced swimming for 1?min at a speed of 10 total lengths (TL)/s. Temperature affects growth. TL increased 0.09?cm at 4?°C versus 0.30?cm at 10?°C. Body mass grew 0.49?g at 4?°C versus 1.65?g at 10?°C, whereas the Fulton’s condition factor increased 0.021 at 4?°C versus 0.080 at 10?°C. The ingested food was more than twofold higher at 10 than at 4?°C, while the feces produced at 4?°C was about twofold higher. The scope between baseline and peak oxygen consumption after forced swimming was affected by temperature, being 4.51 at 5?°C and 3.03 at 10?°C. The percentage energy expenditure until the return of baseline oxygen consumption values showed a marked temperature effect, being higher at 5?°C. We propose the existence of a trade-off in the allocation of energy between swimming activity and growth, with proportionally more energy being consumed at low temperatures for swimming than for other physiological functions like growth.