Testicular 3 beta-hydroxysteroid dehydrogenase/delta 5-4 isomerase in the hypophysectomized rat: effect of treatment with 5 alpha-dihydrotestosterone.

The in-vivo regulatory effect of androgens on steroidogenesis was investigated. Adult (2 to 3 months old) hypophysectomized rats were treated intratesticularly with increasing doses of 5 alpha-dihydrotestosterone (DHT; 10-200 micrograms/100 g body weight) or vehicle (50 microliters dimethyl sulphoxide; DMSO) in the contralateral testis. Intratesticular testosterone concentrations were extremely low in hypophysectomized rats 15-20 days after surgery. Treatment with DHT caused a dose-dependent inhibition of testicular 3 beta-hydroxysteroid dehydrogenase/delta 5-4 isomerase (3 beta-HSD) 2 h later, and this effect was apparent at the dose of 20 micrograms/100 g body weight (P less than 0.01). The inhibitory effect of 3 beta-HSD was not due to a possible interference of DHT in the enzyme assay, since various concentrations of the androgen (0.1-100 mumol/l) were ineffective as inhibitors of 3 beta-HSD. The highest dose of DHT used in this study (200 micrograms/100 g body weight) resulted in a rapid (1-2 h) and transient (4-6 h) inhibition (approximately 80%) of 3 beta-HSD activity. Pretreatment of rats with the antiandrogen cyproterone acetate (5 mg/rat) or the protein synthesis inhibitor cycloheximide (10 mg/rat) did not affect the enzyme activity of testes injected with DMSO, but counteracted the inhibitory effect of DHT on 3 beta-HSD activity in the contralateral testis. The results presented suggest that the inhibitory effect of the non-aromatizable androgen DHT is receptor-mediated and involves the synthesis of a factor(s) that modulates 3 beta-HSD activity.     

Glucagon induces the plasma membrane insertion of functional aquaporin-8 water channels in isolated rat hepatocytes

Although glucagon is known to stimulate the cyclic adenosine monophosphate (cAMP)-mediated hepatocyte bile secretion, the precise mechanisms accounting for this choleretic effect are unknown. We recently reported that hepatocytes express the water channel aquaporin-8 (AQP8), which is located primarily in intracellular vesicles, and its relocalization to plasma membranes can be induced with dibutyryl cAMP. In this study, we tested the hypothesis that glucagon induces the trafficking of AQP8 to the hepatocyte plasma membrane and thus increases membrane water permeability. Immunoblotting analysis in subcellular fractions from isolated rat hepatocytes indicated that glucagon caused a significant, dose-dependent increase in the amount of AQP8 in plasma membranes (e.g., 102% with 1 micromol/L glucagon) and a simultaneous decrease in intracellular membranes (e.g., 38% with 1 micromol/L glucagon). Confocal immunofluorescence microscopy in cultured hepatocytes confirmed the glucagon-induced redistribution of AQP8 from intracellular vesicles to plasma membrane. Polarized hepatocyte couplets showed that this redistribution was specifically to the canalicular domain. Glucagon also significantly increased hepatocyte membrane water permeability by about 70%, which was inhibited by the water channel blocker dimethyl sulfoxide (DMSO). The inhibitors of protein kinase A, H-89, and PKI, as well as the microtubule blocker colchicine, prevented the glucagon effect on both AQP8 redistribution to hepatocyte surface and cell membrane water permeability. In conclusion, our data suggest that glucagon induces the protein kinase A and microtubule-dependent translocation of AQP8 water channels to the hepatocyte canalicular plasma membrane, which in turn leads to an increase in membrane water permeability. These findings provide evidence supporting the molecular mechanisms of glucagon-induced hepatocyte bile secretion.     

Isotope Ratio Mass Spectrometry (IRMS) Versus Laser-Assisted Ratio Analyzer (LARA)

This study was carried out to compare the measurements and the diagnostic accuracy of the traditional expensive IRMS and the new economical LARA system using two doses of [¹³C]urea + two different test meals in patients undergoing upper gastrointestinal endoscopy, both before and after anti-Helicobacter treatment. A total of 354 dyspeptic patients underwent endoscopy with gastric biopsies to diagnose H. pylori infection by CLO-test and histology. No patients had taken antibiotics, bismuth, or antisecretory drugs in the 4 weeks before testing. After overnight fasting, breath samples were collected simultaneously in both plastic and glass tubes at baseline and at 30 and 60 min after urea ingestion. In 237 patients 100 mg [¹³C]urea + Ensure and in 117 patients 75 mg [¹³C]urea + citric acid were given. The test was also performed with the two urea dosages and meals in 67 and 64 infected patients, respectively, four weeks after anti-Helicobacter therapy. H. pylori was considered eradicated when both biopsy-based tests were negative. A value >5 was considered positive. Breath samples with insufficient CO₂ levels at both 30 and 60 min were excluded from final analysis (N = 37 in pre- and N = 8 in posttreatment). There was excellent agreement between overall values of the two machines with both [¹³C]urea 100 mg + Ensure and [¹³C]urea 75 mg + citric acid. The 95% CI of the difference against the mean was wider with the former (mean –1.3, +6.3, and –9.4) than with the latter urea dosage and test meal (mean –1.2, +5.2 and –8.1). LARA and IRMS were equally effective (P = NS) in distinguishing infected from uninfected patients before therapy using both doses of [¹³C]urea and test meals (sensitivity ranged from 95% to 99% and specificity from 95% to 97%). This good performance was maintained in the posttreatment phase (sensitivity ranged from 90% to 100% and specificity from 90% to 97%), without any statistical difference among the various combinations (P = NS). The LARA system is a valid alternative to IRMS in the diagnosis of H. pylori infection. Both machines provide highly reliable results after 30 min, so that the 60 min sample can be avoided. The dose of 75 mg + citric acid suffices to ensure an accurate UBT. The test performed with both devices and [¹³C]urea dosages is very effective also for posttherapy evaluation of H. pylori status.     

Is Rhodnius prolixus (Triatominae) invading houses in central Brazil?

Sylvatic triatomines of the genus Rhodnius commonly fly into houses in Latin America, maintaining the risk of Chagas disease transmission in spite of control efforts. In the recent past, adult bugs collected inside houses in central Brazil were identified as R. prolixus, a primary disease vector whose natural geographical range excludes this region. Three nearly sibling species (R. neglectus, R. nasutus, and R. robustus), secondary vectors with limited epidemiological significance, occur naturally south of the Brazilian Amazon. The specific status of Rhodnius specimens found inside houses in central Brazil is therefore an epidemiologically important (and still debated) issue. We used wing and head geometric morphometrics to investigate the taxonomic status of 230 adult specimens representing all four 'R. prolixus group' species (19 populations from palm trees, domiciles, and reference laboratory colonies). Discriminant analyses of shape variation allowed for an almost perfect reclassification of individuals to their putative species. Shape patterning revealed no consistent differences between most specimens collected inside houses in central Brazil and R. neglectus, and showed that R. robustus and R. neglectus occur sympatrically (and fly into houses) in southern Amazonia. Furthermore, all Brazilian specimens clearly differed from our reference R. prolixus population. Using geometric morphometrics, we confidently ascribed individual triatomines to their species within the problematic 'R. prolixus group', illustrating the potential value of this approach in entomological surveillance. Our results strongly support the idea that R. neglectus, and not R. prolixus, is the species invading houses in central Brazil.     

The CB1 cannabinoid receptor mediates glucocorticoid-induced effects on behavioural and neuronal responses during lactation

It has been shown that glucocorticoids can modulate oxytocin (OT) secretion and disrupt maternal behaviour. Because the CB1 receptor (CB1R) has been implicated in some rapid glucocorticoid-induced actions, the present study aimed to evaluate the possible involvement of CB1Rs in maternal behaviour and neuronal activation during lactation. For this purpose, lactating female rats were pre-treated with dexamethasone (DEX) or saline, followed by treatment with AM251, a CB1R antagonist, or vehicle 90 min later. All of the experiments were performed 30 min after the administration of AM251 or vehicle. To evaluate maternal behaviour, the pups were returned to their home cages to the side of the cage opposite the previous nest after 12 h of separation and were filmed for the next 30 min. Aggressive behaviour was evaluated for 10 min following the placement of a male rat in the home cage. For the evaluation of behavioural performance, lactating rats were subjected to a T-maze and open-field tests. The amount of weight gained by the pups was evaluated 15 min after the onset of suckling to determine the amount of milk that they had obtained from the dam. In the central nervous system of lactating rats, c-Fos-positive nuclei were counted in the medial preoptic area, in both the ventral (v) and dorsal (d) parts of the median preoptic nucleus and in the bed nucleus of the stria terminalis (BNST). The number of neurons that were double-labelled for c-Fos/OT was counted in the medial magnocellular subdivision of the paraventricular nucleus, in the periventricular hypothalamic nucleus and in the supraoptic nucleus of the lactating rats. The results show that DEX had the following effects: (1) decreased the amount time the dam spent licking the pups, the amount of time the dam spent in an arched-nursing position and full maternal behaviour; (2) increased the latency to the first attack and decreased front attacks; (3) increased anxiety-like behaviour; and (4) decreased weight gain in the pups. In addition, DEX decreased neuronal activation in all of the investigated hypothalamic and forebrain areas. AM251 administration reversed these parameters, indicating that the behavioural effects and neuronal responses produced by DEX in lactating rats are likely to be mediated by CB1Rs.     

Pharmacokinetics of cannabidiol in children with refractory epileptic encephalopathy

Growing interest in the clinical use of cannabidiol (CBD) as adjuvant therapy for pediatric refractory epileptic encephalopathy emphasizes the need for drug treatment optimization. The aim of this study was to characterize the pharmacokinetics of CBD in pediatric patients with refractory epileptic encephalopathy receiving an oil‐based oral solution. To evaluate CBD concentrations, six serial blood samples per patient were collected after the morning dose of CBD, at least 21 days after the beginning of treatment. Twelve patients who received a median (range) dose of 12.2 (5.3‐19.4) mg/kg/d (twice daily) were included in the analysis. Median (range) CBD time to maximum plasma concentration, maximum plasma concentration, and area under the concentration versus time curve up to 6 hours after dosing were 3.2 hours (1.9‐6.2), 49.6 ng/mL (14.4‐302.0), and 226.3 ng ? h/mL (70.5‐861.3), respectively. CBD systemic exposure parameters were in the lower range of previous reports in pediatric patients receiving doses in a similar range. Most of our patients (83%) showed little CBD plasma level fluctuation during a dosing interval, comparable to that encountered after oral administration of an extended release drug delivery system. CDB administration was generally safe and well tolerated, and a novel levothyroxine‐CBD interaction was recorded. Similar to other studies, large interindividual variability in CBD exposure was observed, encouraging the use of CBD therapeutic drug monitoring.     

PLP1 gene analysis in 88 patients with leukodystrophy

Pelizaeus–Merzbacher disease (PMD) is caused in most cases by either duplications or point mutations in the PLP1 gene. This disease, a dysmyelinating disorder affecting mainly the central nervous system, has a wide clinical spectrum and its causing mutations act through different molecular mechanisms. Eighty‐eight male patients with leukodystrophy were studied. PLP1 gene analysis was performed by the Multiplex Ligation‐dependent Probe Amplification technique and DNA sequencing, and, in duplicated cases of PLP1, gene dosage was completed by using array‐CGH. We have identified 21 patients with mutations in the PLP1 gene, including duplications, short and large deletions and several point mutations in our cohort. A customized array‐CGH at the Xq22.2 area identified several complex rearrangements within the PLP1 gene region. Mutations found in the PLP1 gene are the cause of PMD in around 20% of the patients in this series.     

Relationship between children physical activity,inflammatory mediators and lymphocyte activation: possible impact of social isolation (COVID-19)

Sport Sciences for Health - Lifestyle and body composition may be simultaneously responsible for immune response modulation. This study aimed to compare plasmatic adipokines concentration and...     

Effect of new thiazolidine derivatives LPSF/GQ-02 and LPSF/GQ-16 on atherosclerotic lesions in LDL receptor-deficient mice (LDLR−/−)

BackgroundAtherosclerotic cardiovascular disease is a chronic inflammatory condition. Thiazolidinediones (TZDs) are used to enhance sensitivity to insulin and have demonstrated a protective effect over a variety of cardiovascular markers and risk factors. Controversially, the TZDs are associated with the development of heart failure. Thus, lines of research have invested in the search for new molecules in order to obtain more selective and less harmful treatment alternatives for the pathogenesis of atherosclerosis and its risk factors.MethodsAnimals were fed a diet rich in fat for 10 weeks. In the last 2 weeks, animals received either pioglitazone, LPSF/GQ-02, or LPSF/GQ-16 daily through gavage. At the end of the treatment, blood was collected for biochemical analysis and the aortas were dissected for subsequent analyses.ResultsNo changes in the blood lipid profile were found following the use of the drugs in comparison to the control. However, the new thiazolidine derivatives were more efficient in improving insulin resistance in comparison to pioglitazone and the control group. Morphometric analyses revealed that neither pioglitazone nor LPSF/GQ16 led to satisfactory effects over atherosclerosis. However, LPSF/GQ-02 led to a reduction in area of the atherosclerotic lesions. Ultrastructural analyses revealed extensive degeneration of the endothelium and an increase in apoptotic cells in the subendothelial space following the use of pioglitazone and LPSF/GQ-16. However, LPSF/GQ-02 caused minimal cell alterations in the aortic endothelium. Regarding markers, endothelial nitric oxide synthase (eNOS) and matrix metalloproteinase 9 (MMP-9), LPSF/GQ-16, and pioglitazone exerted similar effects, increasing the expression of MMP-9, and had no effect on the expression of eNOS compared with the control group. On the other hand, LPSF/GQ-02 was effective in reducing the expression of MMP-9 and increased eNOS significantly.ConclusionsThe results suggest that the new thiazolidine derivative LPSF/GQ-02 is a promising candidate for the treatment of atherosclerosis.