Mild Temperature Increase Research Articles

Studying Thermopriming-Mediated Short- and Long-Term Acquired Thermotolerance in Arabidopsis thaliana.

High temperature is one of the most devastating environmental factors that severely impede plant growth multi-laterally and threatens global food security. Global warming and the predicted steady rise in temperature emphasize the urgent need to improve heat stress resilience of crop plants to meet the growing food demand. Although known for several years, a memory-based mechanism termed "priming-induced stress tolerance" or "acquired stress tolerance" has gained the attention of the plant science community in recent years. Thermopriming is one such phenomenon that enhances the plant tolerance to subsequent heat stress and promotes growth. The memory of the foregoing mild increase in temperature is captured and retained as dormant signals, which upon exposure to subsequent high temperature aids in mounting a faster, stronger, and sensitized response. Such acquired thermotolerance is more effective than the basal endurance of the plant due to altered molecular regulatory networks. Thereupon, thermopriming can be used as a convenient tool to study and improve plant response to heat stress. In this chapter, the protocol to study thermopriming-mediated short- and long-term acquired thermotolerance is described in detail.

Hidden Dynamics of Noble-metal-bound Thiol Monolayers Revealed by SERS-monitored Entropy-driven Exchange of Cysteine Isotopologues

Vibrational spectroscopy coupled with isotopic labeling provides insight into the dynamics of various molecular processes. Here, a newfound approach in surface-enhanced Raman scattering (SERS) spectroscopy to study noble metal-anchored thiol monolayers is demonstrated for a pair of L-cysteine isotopologues competing for binding to silver nanoparticles (AgNPs): Cys-cabn (all 12C/14N) and Cys-CABN (all 13C/15N). As predicted by our DFT calculations, a distinct difference in the Raman shift value (>50 cm−1) of the ν(C = O) band was observed for these two AgNP-anchored isotopologues. SERS intensity ratio of these two peaks allowed for quantitative monitoring of an exclusively entropy-driven exchange of Cys molecules between the surface and the solution, revealing a reversible and rapid activation after a mild temperature increase (50 °C). This behavior is attributed to the collective phase transition within the monolayer. This work highlights unexplored potential of SERS spectroscopy coupled with isotopic exchange to study dynamic phenomena within a metal-anchored layer.

Sensitive microscale thermophoresis assay for rapid ochratoxin A detection with fluorescently labeled engineered aptamer.

Ochratoxin A (OTA) is a widespread mycotoxin that causes contamination in a variety of foodstuffs and environments, inducing great health risks to humans and animals. Rapid and sensitive detection of OTA is necessary for food safety, environmental health, and risk assessment. Herein, we report an aptamer microscale thermophoresis (MST) assay for OTA, with the unique merits of ratiometric analysis, rapid measurement, simple operation, high sensitivity, low sample consumption, and high throughput. A fluorescein (FAM)-labeled high-affinity DNA aptamer with a G-quadruplex and duplex structure was used as the recognition element for OTA, and MST, which measures the fluorescence responses of the sample solution inside capillaries to a mild temperature increase generated by infrared laser heating, was employed for signal generation. Upon OTA binding, the FAM-labeled aptamer probe underwent changes in conformation and stability, and the bound and unbound aptamer probes showed significant differences in their MST signals. To achieve sensitive detection of OTA with a large signal change, we systematically characterized aptamers with different stem lengths, which had large effects on the MST responses of the aptamer probes to OTA. We found that a 32-mer aptamer with FAM label at the 3' end gave a sensitive MST response to OTA, allowing OTA detection within seconds with a detection limit of 0.98 nM under optimal experimental conditions. This aptamer MST assay shows potential in real sample analysis and broad applications.

Ayurvedic Management on Covid-19: A Case Report

Severe acute respiratory syndrome, also known as SARS-Cov-2 or Covid-19, first emerged in march 2020. It has many of the same symptoms as influenza, including a dry cough, headache, body ache, mild increase in body temperature, trouble in breathing, low oxygen levels, nausea, and vomiting. Clinical results of early-stage Covid-19 patients receiving Ayurvedic treatment. Ashwagandha ghan vati and Giloye ghan vati with herbal immune tea or Kahda of Tulsi leaves, ginger, Haldi, Giloye, and Mulaithi, among other ingredients, were used as the first line of treatment. This conventional approach lasted for seven days and included a liquid diet of fresh mosambi and fresh coconut water as well as complete bed rest. The improvement of the Covid -19 afflicted patient's greatest recovery was successfully discovered with the use of a 7-day protocol therapy. Deep breathing exercises, Bhastrika, and Anuloma-Viloma in particular, gave the lungs the vigour they needed to enhance the respiratory system.

Agranulocytosis following intravenous immunoglobulin administration in a patient with Guillain-Barré Syndrome triggered by COVID-19: A case report

Neutropenia during recovery after coronavirus disease 2019 (COVID-19), as well as neutropenia after intravenous immunoglobulin (IVIG) administration are very rare hematological abnormalities. We report the first case of agranulocytosis following IVIG administration in patients with Guillain-Barre syndrome (GBS) triggered by COVID-19. A 62-year-old female patient was admitted to the Emergency Department due to progressive limb weakness and sensory disturbances that began two weeks before admission. Five weeks before admission she was treated for COVID-19 and has fully recovered. She was diagnosed with Guillain-Barre syndrome (GBS), and treatment with IVIG was started. Twenty hours after the first dose of IVIG, blood analysis showed neutropenia and thrombocytopenia, and after the fifth dose she developed agranulocytosis followed by mild increase in body temperature. Granulocyte colony-stimulating factor (G-CSF) was administered and after 12 hours the leukocyte lineage recovered. According to the previous findings, neutropenia after IVIG administration might be related to CD11b, and COVID-19 is associated with an increase in immature neutrophil populations in the later stages of the disease defined by their expression of CD11b. Meanwhile, some finding suggests that corticosteroid pretreatment prevent neutropenia after IVIG administration, which might be important because many patients with post-COVID GBS have been treated with corticosteroids for COVID-19.

Multi-depth evolution characteristics of soil moisture over the Tibetan Plateau in the past 70 years using reanalysis products

Soil moisture (SM) is a crucial component of the hydrological cycle. Both the spatial–temporal distribution and the variation characteristics of SM are effective indicators of regional land surface water resource homogeneity and heterogeneity. With consideration of the crucial role of the Tibetan Plateau (TP) in the hydrological process in Asia, this study investigated the fluctuation of multi-depth soil moisture across the TP during 1950–2020 on a monthly scale against the background of global warming by using ERA5 reanalysis datasets. The correlation and potential causality between soil moisture and associated driving factors were explored. Our research revealed that the soil moisture across the TP shows a slight wetting trend at 0–100 cm depth for the past 70 years against the background of climate warming and increasing precipitation. Additionally, the wetting region (variation trend ≥ 0.005 m3/m3 per decade) had sufficient water supplementation from precipitation and a mild soil temperature increase. By comparison, there is a noteworthy warming tendency and falling precipitation in the sparsely distributed drying region (variation trend ≤ −0.005 m3/m3 per decade). In terms of vertical variation features, the temporal dynamic fluctuation of soil moisture and soil temperature evidently decreases as the depth increases, suggesting high sensitivity of the surface layer soil to atmospheric conditions. Precipitation and snowmelt preliminarily proved to be the dominant drivers causing spatial and temporal variations in soil moisture (occupying over 70% of the TP region), and bidirectional causality (ranging between 15.52% and 50.56%) was found between soil moisture and these two parameters. In summary, this study explored the spatial–temporal fluctuation in the evolutionary characteristics of SM, which is expected to advance our understanding of soil moisture dynamics under the conditions of climate change across the TP.

Development and Evaluation of a Serum Transfusion Process in the Thorny Devil Stick Insect (Eurycantha calcarata)

The thorny devil stick insect (Eurycantha calcarata) is a common invertebrate maintained under human care. Blood (hemolymph) transfusions are a widely used therapeutic tool in other species, but investigation in terrestrial arthropods remains scarce. Study objectives were development and evaluation of a serum transfusion process in the thorny devil stick insect. Twenty-five clinically healthy adult insects (9.9–23.0 g) were enrolled and baseline body weights were collected. Hemolymph collection was not successful in males, thus, all were recipient only (n = 12, MR). Females were divided into donor (n = 4, FD) or donor and recipient (n = 9, FDR) groups. Females were manually restrained and up to 1 mL of hemolymph was collected from the abdominal segment caudal to the proximal hindlimb using an 18 g hypodermic needle and passive collection via gravity. Hemolymph was quantified, centrifuged, and the serum separated. Insects were then injected superficially at the lateral aspect of the abdomen with 0.01 mL/g FD serum (MR), lactated Ringer's solution (LRS) equal to collected hemolymph volume (FD), or a combination of FDR serum and LRS equal to collected hemolymph volume (FDR). Response to stimulation, surface temperature, and righting reflex and mortality were serially assessed for up to 24 h and 7 days, respectively, following injection. In FD, median (range) injected LRS dose was 0.04 (0.03–0.06) mL/g. In FDR, median (range) injected serum, LRS, and combined serum and LRS dose was 0.03 (0.02–0.04), 0.01 (0–0.04), and 0.04 (0.02–0.06) mL/g, respectively. A mild temperature increase (maximum +2.9°C) (MR n = 10, FD n = 3, FDR n = 8) and delayed righting reflex (MR n = 4, FD n = 3, FDR n = 7) occurred in a subset of insects following injection. Two deaths occurred at 2 min (n = 1, FDR) and 96 h (n = 1, FD) post-injection. This is the first report of serum transfusions in thorny devil stick insects, and while largely successful, minor to severe transfusion reactions may occur.

HsfA7 coordinates the transition from mild to strong heat stress response by controlling the activity of the master regulator HsfA1a in tomato.

Plants respond to higher temperatures by the action of heat stress (HS) transcription factors (Hsfs), which control the onset, early response, and long-term acclimation to HS. Members of the HsfA1 subfamily, such as tomato HsfA1a, are the central regulators of HS response, and their activity is fine-tuned by other Hsfs. We identify tomato HsfA7 as capacitor of HsfA1a during the early HS response. Upon a mild temperature increase, HsfA7 is induced in an HsfA1a-dependent manner. The subsequent interaction of the two Hsfs prevents the stabilization of HsfA1a resulting in a negative feedback mechanism. Under prolonged or severe HS, HsfA1a and HsfA7 complexes stimulate the induction of genes required for thermotolerance. Therefore, HsfA7 exhibits a co-repressor mode at mild HS by regulating HsfA1a abundance to moderate the upregulation of HS-responsive genes. HsfA7 undergoes a temperature-dependent transition toward a co-activator of HsfA1a to enhance the acquired thermotolerance capacity of tomato plants.

Combination therapy with PD-1 blockade and radiofrequency ablation for recurrent hepatocellular carcinoma: a propensity score matching analysis

Background This study aimed to evaluate whether combined therapy with PD-1 blockade (anti-PD-1) and radiofrequency ablation (RFA) is superior to RFA monotherapy for recurrent hepatocellular carcinoma (HCC). Methods A total of 127 patients who underwent anti-PD-1 plus RFA treatment (n = 41) or RFA alone (n = 86) for recurrent HCC were included in this retrospective study. A matched cohort comprising 40 patients from each group was selected after propensity score matching analysis. Clinical data including post-RFA HCC recurrence (primary endpoint), overall survival (OS) (secondary endpoint), adverse events, and toxic effects were retrospectively analyzed. Results The 1-year recurrence-free survival rates for the anti-PD-1 plus RFA and RFA groups were 32.5% and 10.0% after propensity score matching. There were statistically significant differences between the two groups in terms of the recurrence-free survival rate (p = 0.001) and OS rate (p = 0.016). Tumor number, tumor-node metastasis (TNM) stage, antiviral therapy, and anti-PD-1 treatment were demonstrated to be important factors associated with 1-year recurrence-free survival probability by univariate and multivariate analyses. Univariate and multivariate analyses demonstrated that tumor number, TNM stage and anti-PD-1 treatment were significant prognostic factors for OS. RFA treatment-related adverse events included pleural effusions that require drainage and a mild or moderate increase in body temperature. Grade 3 or higher events related to anti-PD-1 treatment occurred in 12.8% (6) of patients and were infrequent. Conclusions Combination therapy with anti-PD-1 plus RFA was superior to RFA alone in improving survival in patients with recurrent HCC.

Warm nights disrupt transcriptome rhythms in field-grown rice panicles

In rice, a small increase in nighttime temperature reduces grain yield and quality. How warm nighttime temperatures (WNT) produce these detrimental effects is not well understood, especially in field conditions where the typical day-to-night temperature fluctuation exceeds the mild increase in nighttime temperature. We observed genome-wide disruption of gene expression timing during the reproductive phase in field-grown rice panicles acclimated to 2 to 3 °C WNT. Transcripts previously identified as rhythmically expressed with a 24-h period and circadian-regulated transcripts were more sensitive to WNT than were nonrhythmic transcripts. The system-wide perturbations in transcript levels suggest that WNT disrupt the tight temporal coordination between internal molecular events and the environment, resulting in reduced productivity. We identified transcriptional regulators whose predicted targets are enriched for sensitivity to WNT. The affected transcripts and candidate regulators identified through our network analysis explain molecular mechanisms driving sensitivity to WNT and identify candidates that can be targeted to enhance tolerance to WNT.

Experimental model of occluded biliary metal stent recanalization using irreversible electroporation via a tubular catheter

Purpose To demonstrate the feasibility of irreversible electroporation (IRE) for treating biliary metal stent occlusion in an experimental liver model. Methods and materials IRE was performed using an expandable tubular IRE-catheter placed in nitinol stents in the porcine liver. A 3-electrode IRE-catheter was connected to an IRE-generator and one hundred 100μs pulses of constant voltage (300, 650, 1000, and 1300 V) were applied. Stent occlusion was simulated by insertion of liver tissue both ex vivo (n = 94) and in vivo in 3 pigs (n = 14). Three scenarios of the relationship between the stent, electrodes, and inserted tissue (double contact, single contact, and stent mesh contact) were studied. Electric current was measured and resistance and power calculated. Pigs were sacrificed 72 h post-procedure. Harvested samples (14 experimental, 13 controls) underwent histopathological analysis. Results IRE application was feasible at 300 and 650 V for the single and double contact setup in both ex vivo and in vivo studies. Significant differences in calculated resistance between double contact and single contact settings were observed (ex-vivo p ˂ 0.0001, in-vivo p = 0.02; Mann–Whitney). A mild temperature increase of the surrounding liver parenchyma was noted with increasing voltage (0.9–5.9 °C for 300–1000 V). The extent of necrotic changes in experimental samples in vivo correlated with the measured electric current (r 2 = 0.39, p = 0.01). No complications were observed during or after the in-vivo procedure. Conclusion Endoluminal IRE using an expandable tubular catheter in simulated metal stent occlusion is feasible. The relationship of active catheter electrodes to stent ingrowth tissue can be estimated based on resistance values.

Structural stability of SARS-CoV-2 virus like particles degrades with temperature

SARS-CoV-2 is a novel coronavirus which has caused the COVID-19 pandemic. Other known coronaviruses show a strong pattern of seasonality, with the infection cases in humans being more prominent in winter. Although several plausible origins of such seasonal variability have been proposed, its mechanism is unclear. SARS-CoV-2 is transmitted via airborne droplets ejected from the upper respiratory tract of the infected individuals. It has been reported that SARS-CoV-2 can remain infectious for hours on surfaces. As such, the stability of viral particles both in liquid droplets as well as dried on surfaces is essential for infectivity. Here we have used atomic force microscopy to examine the structural stability of individual SARS-CoV-2 virus like particles at different temperatures. We demonstrate that even a mild temperature increase, commensurate with what is common for summer warming, leads to dramatic disruption of viral structural stability, especially when the heat is applied in the dry state. This is consistent with other existing non-mechanistic studies of viral infectivity, provides a single particle perspective on viral seasonality, and strengthens the case for a resurgence of COVID-19 in winter.

Diagnostic reliability of clinical signs in cows with traumatic reticuloperitonitis and abomasal ulcers

BackgroundClinical signs of traumatic reticuloperitonitis and abomasal ulcer are often similar making the disorders difficult to differentiate. The goal of our study was to compare the frequency of individual clinical signs of cows with traumatic reticuloperitonitis and cows with abomasal ulcers and determine their diagnostic significance. The frequency of the findings “rectal temperature, heart rate, respiratory rate, demeanour, signs of colic, arched back, abdominal guarding, bruxism, scleral vessels, rumen motility, foreign body tests, percussion auscultation, swinging auscultation and faecal colour” of cows with traumatic reticuloperitonitis (TRP, n = 503) and cows with type 1 (U1, n = 94), type 2 (U2, n = 145), type 3 (U3, n = 60), type 4 (U4, n = 87) and type 5 (U5, n = 14) abomasal ulcer were compared, and the reliability indices “diagnostic sensitivity and specificity, positive and negative predictive values and positive likelihood ratio” were calculated. A total of 182 healthy cows served as controls (control group).ResultsNone of the cows in the control group had colic, rumen atony or melena, 99% had no abnormalities in demeanor and appetite and did not have a rectal temperature of ≤38.6 or > 40.0 °C, a heart rate > 100 bpm or a respiratory rate > 55 breaths per min, and 95% did not have an arched back or bruxism. The control group was therefore ideal for comparative purposes. Many signs such as mild increase in rectal temperature, scleral congestion and positive foreign body test were non-diagnostic because they occurred in healthy as well as in ill cows. Likewise, differentiation of cows with TRP and abomasal ulcer was not possible based on single clinical variables; a detailed history and a comprehensive assessment of all clinical findings were required for this.ConclusionsThe findings of the present study serve as a guide for the veterinarian in the differentiation of cows with traumatic reticuloperitonitis and abomasal ulcer.

The heat shock transcription factor HSF-1 protects Caenorhabditis elegans from peroxide stress

Cells induce conserved defense mechanisms that protect them from oxidative stress. How these defenses are regulated in multicellular organisms is incompletely understood. Here, we show that the heat shock transcription factor HSF-1 protects the nematode Caenorhabditis elegans from the oxidative stress caused by environmental peroxide. In response to a heat shock or a mild temperature increase, HSF-1 protects the nematodes from subsequent peroxide stress in a manner that depends on HSF-1’s transactivation domain. At constant temperature, HSF-1 protects the nematodes from peroxide stress independently of its transactivation domain, likely by inducing the expression of asp-4/cathepsin and dapk-1/dapk. Thus, two distinct HSF-1-dependent processes protect C. elegans from peroxide stress.

Mild experimental increase in testis and epididymis temperature in men: effects on sperm morphology according to spermatogenesis stages.

A mild increase in testicular and epididymal temperatures in men, bulls and rams (pendulous scrotum) inhibits spermatogenesis and increases the percentage of sperm with an abnormal morphology. However, the stages of spermatogenesis that are most sensitive to a mild increase in testicular temperature in men are unknown. The aim of the present study was to explore the effects of a mild induced increase in testicular and epididymal temperature (i.e., testicular temperature maintained below the core body temperature) on sperm morphology in humans depending on the physiological time of spermatogenesis and epididymal transit. Five healthy volunteers were enrolled in an experimental study in which testicular and epididymal temperatures were increased by maintaining the testes in a supra-scrotal position with a specially designed underwear worn 15±1 h a day for 120 consecutive days. Semen collection was scheduled on specific days depending on spermatogenic stages and epididymal transit. Sperm morphology and the multiple anomalies index (MAI) were analysed before, during and after heating. This mild induced increase in testicular and epididymal temperatures resulted in a significant rise in the percentage of morphologically abnormal spermatozoa on day 34 of heating, which remained elevated throughout the heating period and persisted until 45 days after cessation of heating. The MAI was significantly increased on day 20 throughout the heating period and persisted 45 days after cessation of heating. An increase in the percentage of anomalies in the sperm head, acrosome or tail occurred on days 34 and/or 45 of heating. Abnormal sperm morphology and MAI reverted to control values 73 days after cessation of heating. A mild sustained increase in testicular and epididymal temperature in man leads morphological abnormalities in spermatozoa mainly due to an impairment of spermiogenesis and meiosis.

Shifts in dimethylated sulfur concentrations and microbiome composition in the red-tide causing dinoflagellate <i>Alexandrium minutum</i> during a simulated marine heatwave

Abstract. The biogenic sulfur compounds dimethyl sulfide (DMS), dimethyl sulfoniopropionate (DMSP) and dimethyl sulfoxide (DMSO) are produced and transformed by diverse populations of marine microorganisms and have substantial physiological, ecological and biogeochemical importance spanning organism to global scales. Understanding the production and transformation dynamics of these compounds under shifting environmental conditions is important for predicting their roles in a changing ocean. Here, we report the physiological and biochemical response of a robust strain of Alexandrium minutum, a dinoflagellate with the highest reported intracellular DMSP content, exposed to a 6 d increase in temperature mimicking mild and extreme coastal marine heatwave conditions (+4 and +12 ∘C). Under mild temperature increases (+4 ∘C), A. minutum growth was enhanced, with no measurable physiological stress response. However, under a very acute increase in temperature (+12 ∘C) triggering thermal stress, A. minutum growth declined, photosynthetic efficiency (FV∕FM) was impaired, and enhanced oxidative stress was observed. These physiological responses indicative of thermal stress were accompanied by increased DMS and DMSO concentrations followed by decreased DMSP concentration. At this temperature extreme, we observed a cascading stress response in A. minutum, which was initiated 6 h after the start of the experiment by a spike in DMS and DMSO concentrations and a rapid decrease in FV∕FM. This was followed by an increase in reactive oxygen species (ROS) and an abrupt decline in DMS and DMSO on day 2 of the experiment. A subsequent decrease in DMSP coupled with a decline in the growth rate of both A. minutum and its associated total bacterial assemblage coincided with a shift in the composition of the A. minutum microbiome. Specifically, an increase in the relative abundance of the operational taxonomic units (OTUs) matching Oceanicaulis (17.0 %), Phycisphaeraceae SM1A02 (8.8 %) and Balneola (4.9 %) as well as a decreased relative abundance of Maribacter (24.4 %), Marinoscillum (4.7 %) and Seohaeicola (2.7 %) were primarily responsible for differences in microbiome structure observed between temperature treatments. These shifts in microbiome structure are likely to have been driven by either the temperature itself, the changing physiological state of A. minutum cells, shifts in biogenic sulfur concentrations, the presence of other solutes, or a combination of all. Nevertheless, we suggest that these results point to the significant effect of extreme heatwaves on the physiology, growth and microbiome composition of the red-tide causing dinoflagellate A. minutum, as well as potential implications for biogenic sulfur cycling processes and marine DMS emissions.

Toward time-resolved laser T-jump/X-ray probe spectroscopy in aqueous solutions

Most chemical and biochemical reactions in nature and in industrial processes are driven by thermal effects that bring the reactants above the energy barrier for reaction. In aqueous solutions, this process can also be triggered by the laser driven temperature jump (T-jump) method, in which the water vibrational (stretch, bend, or combination) modes are excited by a short laser pulse, leading to a temperature increase in the irradiated volume within a few picoseconds. The combination of the laser T-jump with X-ray spectroscopic probes would add element-specificity as well as sensitivity to the structure, the oxidation state, and the spin state of the intermediates of reactions. Here, we present preliminary results of a near infrared pump/X-ray absorption spectroscopy probe to study the ligand exchange of an octahedral aqueous Cobalt complex, which is known to pass through intermediate steps yielding tetrahedral chlorinated as final species. The structural changes of the chemical reaction are monitored with great sensitivity, even in the presence of a mild local increase in temperature. This work opens perspectives for the study of non-light-driven reactions using time-resolved X-ray spectroscopic methods.

Combined effects of benzophenone-3 and temperature on gene expression and enzymatic activity in the aquatic larvae Chironomus riparius

Climate change and pollution are two of the main environmental problems living organisms currently face. Temperature can modify a toxicant's effects and the organism's response to it. Global warming is expected to increase the temperature of freshwater ecosystems. In this work, we analyzed the effect of a mild temperature increase on the acute response of the aquatic larvae Chironomus riparius to the ultraviolet filter benzophenone-3 (BP3). This substance is commonly used in sunscreens and other commercial products and can reach the environment in different ways. We exposed larvae to BP3 at 18.5 or 23 °C for 8 or 24 h and analyzed the acute response at the molecular level. By quantitative real-time polymerase chain reaction (q-PCR), we studied altered messenger RNA (mRNA) levels of genes related to the endocrine system (EcR, InR and Met), detoxification mechanisms (Cyp4d2, Cyp6b7, GST d6, GST o1 and MRP-1) and stress response (Hsp22, Hsp27, Hsp70, HYOU and Gp93). Moreover, enzyme activity was evaluated, with a focus on glutathione-S-transferase (GST), phenoloxidase (PO) and acetylcholinesterase (AChE). Results showed that temperature affected the acute response of this organism by modifying the expression of EcR, Cyp6b7, GST d6, GST o1, MRP-1, Hsp22, Hsp27 and Hsp70 genes. These results suggest that even mild temperature change can affect the response of this organism to BP3 influencing short-term progress of the population. Although longer exposures are required to determine the ability of C. riparius to manage the pollutants in this novel environmental conditions, in order to know the possible mechanisms of detoxification or adaptation that may develop. This research represents a first step in the analysis of multi-stress response in this animal, and opens new possibilities in the toxicity evaluation of this organism in line with the real scenario that organisms face today.

Increase of core temperature affected the progression of kidney injury by repeated heat stress exposure.

An epidemic of chronic kidney disease of unknown etiology (Mesoamerican nephropathy) has emerged in hot regions of Central America. We have demonstrated that dehydration associated with recurrent heat exposure causes chronic kidney disease in animal models. However, the independent influence of core body temperature on kidney injury has not been explored. In the present study, we tested the hypothesis that kidney injury could be accelerated by increasing body temperature independent of external temperature. Wild-type mice were exposed to heat (39.5°C, 30 min, 2 times daily) with or without the mitochondrial uncoupling agent 2,4-dinitrophenol (DNP) for 10 days. Core temperature, renal function, proteinuria, and renal histological and biochemical analyses were performed. Isolated mitochondria markers of oxidative stress were evaluated from kidney tissue. DNP increased body core temperature in response to heat by 1°C (42 vs. 41°C), which was transient. The mild increase in temperature correlated with worsening albuminuria (R = 0.715, P < 001), renal tubular injury, and interstitial infiltration of monocytes/macrophages. Tubular injury was marked in the outer medulla. This was associated with a reduction in kidney tissue ATP levels (nonheated control: 16.71 ± 1.33 nmol/mg and DNP + heat: 13.08 ± 1.12 nmol/mg, P < 0.01), reduced mitochondria, and evidence for mitochondrial oxidative stress. The results of the present study suggest that kidney injury in heat stress is markedly worsened by increasing core temperature. This is consistent with the hypothesis that clinical and subclinical heat stroke may play a role in Mesoamerican nephropathy.

Experimental mild increase in testicular temperature has drastic, but reversible, effect on sperm aneuploidy in men: A pilot study

In mammals testicular and epididymal temperature increase impairs spermatogenesis. This experimental study investigates the effects of a mild testis temperature increase (i.e. testis temperature remains below core body temperature) on sperm aneuploidy in men. In 5 fertile volunteers a testicular temperature increase was induced by maintaining the testes at suprascrotal position using specially designed underwear for 15 ± 1 h daily for 120 consecutive days. After heating men were followed for next 180 days. A control group (27 men) was recruited. Semen samples were collected before, during and after heating period and analyzed for chromosomes X, Y and 18 for aneuploidy using FISH. A total of 234,038 spermatozoa were studied by FISH. At day 34 of heating, mean sperm aneuploidy values were not modified. From day 34 of heating until day 45 post heating, FISH evaluation was not possible due to the drastic fall of sperm count. At day 45 post-heating total sperm aneuploidy percentage was twice higher than before heating whereas. Sex disomy (sperm XY18), sex chromosome nullisomy (sperm 18) were significantly higher than controls. These effects were completely reversed at 180 days post heat exposure. Conclusion: A mild rise in testicular temperature significantly increases sperm aneuploidies, reflecting an effect on the meiosis stage of spermatogenesis. The effect of heating was reversible and suggests that recovery of aneuploidy to normal values requires at least two cycles of spermatogenesis. Nonetheless, the low number of volunteers was a limitation of this pilot study and warrants further research on larger population.