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SARS-CoV-2 in Childhood Cancer in 2020: A Disease of Differences.
Heat stress reduces the reproductive capacity of bulls raised in tropical climate. However, the reestablishment of scrotal thermoregulation and the dynamics of sperm defects emergence after stress are not completely known in buffaloes. Thus, the study aimed to evaluate the effect of short-term heat stress over scrotal thermoregulation and sperm attributes, relating them to spermatogenesis stages. Five buffalo bulls went through scrotal insulation during 48 h (from day 0 to day 2). Semen samples were collected every 7 days (from day -7 to day 49) and analyzed about the progressive motility, viability, and sperm morphology. Heat stress significantly destabilized scrotal thermoregulation (P less then 0.001). Scrotal temperature was from 4.2 to 6.3 °C lower than the core body temperature, except on insulation days (P less then 0.001), and returned to the basal condition five days after the removal of the stressing stimulus. More significant deleterious effects were observed in sperm morphology than in cell concentration, motility, and viability. The chronology of morphologic defects expression demonstrated tail defects (days 7-14), cytoplasmic droplets (days 14-28), and head defects (day 28), returning to pre-insulation condition 35 days after the thermal challenge. Thus, hyperthermia harmed more intensely spermatozoa in epididymal transit, elongated spermatids, and secondary spermatocytes. It is concluded that water buffalo bulls present a peculiar manifestation of sperm morphology after short-term stress, indicating an important difference related to the bovine species. Therefore, during the andrological evaluation of buffalo bulls, it is necessary to avoid the allometric extrapolation between these species.In the event of a marked rise in body temperature, it is often necessary to reduce the temperature quickly. One method to rapidly drop body temperature is cold water immersion. Because carbon dioxide (CO2)-rich water causes cutaneous vasodilation, it may be that CO2-rich water reduces body temperature faster than fresh water. To test that idea, I compared the effects of CO2-rich and tap water immersion on auditory canal temperature (Tac) after passive heating. Nine healthy male subjects participated in the study. Subjects were first immersed for 15 min in a tap water bath at 40 °C to raise body temperature. They then moved to a tap water or CO2-rich water bath at 30 °C to reduce body temperature. CH6953755 Immersion in 40 °C tap water caused Tac to rise 0.64 ± 0.11 °C in the tap water session and 0.71 ± 0.25 °C in the CO2-rich water session (P > 0.05). During the 30 °C water immersion, Tac declined and was significantly lower in CO2-rich water than in tap water. Cooling rates were 0.06 ± 0.04 °C/min in tap water and 0.11 ± 0.05 °C/min in CO2-rich water (P less then 0.05). In addition, both thermal sensation (3.2 ± 1.0 vs. 2.1 ± 0.9; P less then 0.01) and thermal comfort (1.2 ± 0.4 vs. 2.1 ± 0.8; P less then 0.01) were significantly better in CO2-rich water than tap water. These results suggest that CO2-rich water immersion reduces Tac 1.7 times faster than tap water immersion, and that CO2-rich water immersion cools the body more comfortably than tap water immersion.Different organisms (mainly poikilotherms) are subject to environmental fluctuations that could affect their normal physiological functioning (e.g., by destabilization of biomembranes and rupture of biomolecules). As a result, animals regulate their body temperature and adapt to different environmental conditions through various physiological strategies. These adaptations are crucial in all organisms, although they are more relevant in those that have reached a great adaptive diversity such as scorpions. Within scorpions, the genus Urophonius presents species with winter activity, being this a peculiarity within the Order and an opportunity to study the strategies deployed by these organisms when facing different temperatures. Here, we explore three basic issues of lipid remodeling under high and low temperatures, using adults and juveniles of Urophonius achalensis and U. brachycentrus. First, as an indicator of metabolic state, we analyzed the lipidic changes in different tissues observing that low temperatures generate higher quantities of triacylglycerols and fewer amount of structural lipids and sphyngomielin. Furthermore, we studied the participation of fatty acids in adaptive homeoviscosity, showing that there are changes in the quantity of saturated and unsaturated fatty acids at low temperature (mainly 160, 180, 181 and 182). Finally, we observe that there are quantitative and qualitative variations in the cuticular hydrocarbons (with possible water barrier and chemical recognition function). These fluctuations are in some cases species-specific, metabolic-specific, tissue-specific and in others depend on the ontogenetic state.The thirteen-lined ground squirrel (Ictidomys tridecemlineatus) is assumed to be an obligate hibernator - commencing and terminating hibernation on a circannual rhythm, regardless of environmental conditions - but, until now, this assumption had never been fully tested. We housed three groups of captive-born ground squirrels from Aug. 2017 to Aug. 2018 under constant photoperiod (12 h L12 h D) at 5, 16 or 25 °C, and monitored hibernation using body temperature loggers. At 5 and 16 °C all animals hibernated from autumn to spring with no differences in date of first/last torpor or duration of interbout euthermic periods (IBE), but torpor bout duration was 25% shorter at 16 °C. One of 4 animals housed at 25 °C did not hibernate. For the other three 25 °C animals, the first torpor date did not differ from the other groups, but the last torpor bout (5 Feb.) occurred almost 8 weeks earlier. These animals aroused from torpor more frequently and IBE lasted significantly longer, so the total time spent torpid was less than 50% of the other groups. Unlike the 5 or 16 °C animals, 25 °C animals re-entered torpor in late spring 2018. Taken together these data suggest that this species is an obligate hibernator, but that high ambient temperatures can accelerate the endogenous circannual hibernation rhythm.
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