Constant light alters serum hormone levels related to thyroid function in male CD-1 mice

ABSTRACT

Disruptions to the circadian rhythm can lead to altered metabolism. Modification of thyroid function may be a reason why circadian misalignment may contribute to future metabolic disorders. We investigated whether circadian disruption through constant light (LL) can lead to variations in hormone levels associated with thyroid function. Mice were exposed to LL or a 12:12 Light:Dark (LD) cycle for 6 weeks; then glucose tolerance and thyroid hormone levels were measured at ZT 6 and ZT 18. There was day/night variation in glucose tolerance, but LL had no effect. LL reduced TSH, increased fT4, and abolished day/night variation in fT3 and leptin. These findings illustrate that LL alters thyroid-related hormones, providing evidence of a link between circadian disruption and thyroid function.     

Methotrexate enhances 3T3-L1 adipocytes hypertrophy

Methotrexate (MTX) is broadly used in the treatment of chronic inflammatory diseases such as rheumatoid arthritis (RA). The prevalence of metabolic syndrome (MeS) in patients with this condition is relatively high. Given the importance of adipose tissue in the development of obesity metabolic complications, this study aimed to investigate the effect of methotrexate on preadipocyte proliferation, adipogenesis, and glucose uptake by adipocytes. 3T3-L1 preadipocytes proliferation was evaluated by sulforhodamine B staining and ³H-thymidine incorporation, after 24 or 48 h of treatment with MTX (0.1 and 10 μM). Preadipocytes were induced to differentiate with an appropriate adipogenic cocktail in the presence or absence of MTX. Adipogenesis was determined by measuring lipid accumulation after staining with oil red O. ³H-Deoxyglucose (³H-DG) uptake was determined by liquid scintillation counting. MTX treatment reduced culture protein content in a concentration-dependent manner and ³H-thymidine incorporation (P?<?0.05). MTX (0.1 μM) treatment increased lipid accumulation and basal ³H-DG uptake by adipocytes (P?<?0.05). In 0.1 μM MTX-treated adipocytes, insulin stimulation did not result in an increase of ³H-DG uptake, contrarily to what was observed in control cells. These results demonstrate that methotrexate interferes with adipocyte proliferation and promotes the hypertrophic growth of adipocytes. These molecular effects may have implications on metabolic profile of RA patients treated with MTX.     

Impact of unilateral spatial neglect on chronic patient's post-stroke quality of life

Abstract

Background: Unilateral spatial neglect (USN) is the prevalent feature in patients with right-sided stroke. It is diagnosed through the behavior inattention test (BIT) and has a negative impact on patients affecting both their functional capacity and quality of life.

Objective: Here, we aimed to evaluate the impact of USN on the quality of life of patients in the chronic phase of stroke.

Methods: This is a cross-sectional study with stroke patients with USN. After confirming the presence of stroke through neuroimaging examinations and of USN through the BIT, patients’ quality of life was evaluated by using the EUROQOL scale. Spearman’s correlation was used to validate the correlation between patients’ USN and quality of life, with a p?<?.05 representing significant results.

Results: Eighteen individuals were included. When correlating the value of each domain of the EUROQOL scale with the results of the BIT, we observed a negative correlation between mobility (r?=?–0.97; p?=?.000), self-care (r?=?–0.82; p?=?.013), usual activities (r?=?–0.87; p?=?.005); pain or discomfort (r?=?–0.88; p?=?.004), anxiety or depression (r?=?–0.97; p?=?.000), and EUROQOL total score (r?=?–0.97, p?=?.000).

Conclusion: After a correlation between the overall EUROQOL and BIT scores, we suggest that the higher the USN degree is in stroke patients, the worse their perceived quality of life tends to be.     

Cardiomyocyte dysfunction during the chronic phase of Chagas disease

Chagas disease, which is caused by the parasite Trypanosoma cruzi, is an important cause of heart failure. We investigated modifications in the cellular electrophysiological and calcium-handling characteristics of an infected mouse heart during the chronic phase of the disease. The patch-clamp technique was used to record action potentials (APs) and L-type Ca²⁺ and transient outward K⁺ currents. [Ca²⁺]_i changes were determined using confocal microscopy. Infected ventricular cells showed prolonged APs, reduced transient outward K⁺ and L-type Ca²⁺ currents and reduced Ca²⁺ release from the sarcoplasmic reticulum. Thus, the chronic phase of Chagas disease is characterised by cardiomyocyte dysfunction, which could lead to heart failure.     

Adaptation of the 3H-Leucine Incorporation Technique to Measure Heterotrophic Activity Associated with Biofilm on the Blades of the Seaweed Sargassum spp.

The ecological interaction between microorganisms and seaweeds depends on the production of secondary compounds that can influence microbial diversity in the water column and the composition of reef environments. We adapted the ³H-leucine incorporation technique to measure bacterial activity in biofilms associated with the blades of the macroalgae Sargassum spp. We evaluated (1) if the epiphytic bacteria on the blades were more active in detritus or in the biofilm, (2) substrate saturation and linearity of ³H-leucine incorporation, (3) the influence of specific metabolic inhibitors during ³H-leucine incorporation under the presence or absence of natural and artificial light, and (4) the efficiency of radiolabeled protein extraction. Scanning electron microscopy showed heterogeneous distribution of bacteria, diatoms, and polymeric extracellular secretions. Active bacteria were present in both biofilm and detritus on the blades. The highest ³H-leucine incorporation was obtained when incubating blades not colonized by macroepibionts. Incubations done under field conditions reported higher ³H-leucine incorporation than in the laboratory. Light quality and sampling manipulation seemed to be the main factors behind this difference. The use of specific metabolic inhibitors confirmed that bacteria are the main group incorporating ³H-leucine but their association with primary production suggested a symbiotic relationship between bacteria, diatoms, and the seaweed.     

Reproductive measures and chick provisioning of Cory's Shearwater Calonectris diomedea borealis in the Azores

Capsule Timing of breeding influenced wing-length at fledging, and egg size may be an indicator of fledging weight and the amount of food received by chicks.

Aims To investigate chick growth, temporal patterns of chick food provisioning and the importance of indices of parental condition or quality, egg size and hatching date, to predict nestling body mass and wing-length at fledging, and compare breeding and chick feeding characteristics between colonies in the northeast Atlantic.

Methods A survey of Cory's Shearwater nests was carried out at Vila islet. A sample of 52 chicks, ringed and weighed at hatching, was selected to study chick growth and food provisioning.

Results Hatching success (51%) was much lower than fledging success (87%). Both hatching date and egg size contributed to explain wing-length at fledging, but hatching date, which was negatively correlated with wing-length at fledging, had the most important contribution (22%). There was some indication that egg size may explain variation in fledging weight and the amount of food received by chicks. Food delivery and feeding frequency of chicks varied throughout the chick development stage and three phases were distinguished: (1) 0–29 days, the highest feeding frequency values and a linear increase in food delivery; (2) 30–69 days, an oscillation in food delivery and medium feeding frequencies; (3) 70–90+ days, a sharp decrease in both food delivery and feeding frequency.

Conclusion Variation in food availability did not seem sufficient to override the overall importance of indices of parental quality in determining reproductive measures and chick provisioning. Breeding and feeding characteristics were similar between colonies in the northeast Atlantic, with variability in chick provisioning higher further south.