Negative impacts of social isolation on behavior and neuronal functions are recovered after short-term social reintroduction in zebrafish.

Recently, social isolation measures were crucial to prevent the spread of the coronavirus pandemic. However, the lack of social interactions affected the population mental health and may have long-term consequences on behavior and brain functions. Here, we evaluated the behavioral, physiological, and molecular effects of a social isolation (SI) in adult zebrafish, and whether the animals recover such changes after their reintroduction to the social environment. Fish were submitted to 12 days of SI, and then reintroduced to social context (SR). Behavioral analyses to evaluate locomotion, anxiety-like and social-related behaviors were performed after SI protocol, and 3 and 6 days after SR. Cortisol and transcript levels from genes involved in neuronal homeostasis (c-fos, egr, bdnf), and serotonergic (5-HT) and dopaminergic (DA) neurotransmission (thp, th) were also measured. SI altered social behaviors in zebrafish such as aggression, social preference, and shoaling. Fish submitted to SI also presented changes in the transcript levels of genes related to neural activity, and 5-HT/DA signaling. Interestingly, most of the behavioral and molecular changes induced by SI were not found again 6 days after SR. Thus, we highlight that SR of zebrafish to their conspecifics played a positive role in social behaviors and in the expression of genes involved in different neuronal signaling pathways that were altered after 12 days of SI. This study brings unprecedented data on the effects of SR in the recovery from SI neurobehavioral alterations, and reinforces the role of zebrafish as a translational model for understanding the neurobiological mechanisms adjacent to SI and resocialization.

JM-20 potently prevents the onset of caffeine-induced anxiogenic phenotypes in zebrafish (Danio rerio).

Anxiety is among the most prevalent mental disorders present in the general population. Benzodiazepines are the most commonly prescribed drugs for the treatment of anxiety. Using zebrafish as a model organism, we investigated the anxiolytic activity of JM-20, a novel hybrid molecule with a 1,5-benzodiazepine ring fused to a dihydropyridine moiety. Firstly, we carried out some assays to analyze the possible toxicity mediated by JM-20. For this, zebrafish were exposed to different JM-20 concentrations (0-5 µM) for 96 h. Then, using the novel tank test, we evaluated both locomotor and anxiety-like behavior of the animals. Furthermore, brain, liver and plasma were removed to assess toxicity parameters. JM-20 exposure did not cause changes on novel tank, and also did not alter brain viability, hepatic LDH and plasma ALT levels. Afterward, we investigated whether a pre-exposure to JM-20 would prevent the anxiogenic effect evoked by caffeine. In the novel tank test, caffeine significantly decreased the time spent at the top, as well as the number of transitions to the top area. Moreover, caffeine decreased both the total and average time spent in the lit area, as well as increased the number of risk episodes evaluated by the light-dark test. Whole-body cortisol levels were also increased by caffeine exposure. Interestingly, pre-treatment with JM-20 abolished all alterations induced by caffeine. The anxiolytic effect profile of JM-20 was similar to those found for diazepam (positive control). Our findings show, for the first time, the anxiolytic effect of JM-20 in zebrafish, and its relationship with cortisol regulation.

Short exposure to ethyl and methylmercury prompts similar toxic responses in Drosophila melanogaster.

Methylmercury (MeHg) and ethylmercury (EtHg) are important mercury organic forms in terms of human poisoning. Since the comparative effects of compounds are mainly in vitro, this study was designed to investigate the toxicities induced by MeHg and EtHg in an in vivo study using adult Drosophila melanogaster (D. melanogaster). Firstly, we performed a survival curve, where the flies were fed on a medium containing MeHg and EtHg at concentrations ranging from 2.5 to 200 µM, until the end of their lifespan. After that, the concentrations 25 and 200 µM of MeHg and EtHg were chosen to be tested in a short exposure for 5 days. The analysis of survival by Kaplan-Meier plot revealed that all concentrations of MeHg and EtHg reduced significantly the lifespan of the flies. Short exposure to both concentrations of MeHg and EtHg impaired the ability of flies in the climbing assay and induced lipid peroxidation. Only the flies exposed to the highest concentration had viability loss, thiol depletion, and increased reactive species (RS) and Hg levels in the whole body. Our findings indicate that MeHg and EtHg exhibit similar toxic effects in vivo, and that oxidative stress is a phenomenon behind the toxicity of both mercurials. The data obtained also reinforce the use of D. melanogaster as a useful organism for basic toxicological research.

When eating makes you sick - Gastric stump obstruction caused by a phytobezoar. A case report and literature review.

INTRODUCTION AND IMPORTANCE: Bezoars result from undigested material having an incidence of 0.4-1% (Gunner et al., 2012). Impaired gastrointestinal motility is one of the risk factors. The aim of this article is to highlight the importance of this commonly disregarded entity as well as the different treatment modalities available. CASE PRESENTATION: A 68-year-old female presented to our emergency department complaining of colicky lower left abdominal pain associated with vomiting and absence of bowel movements for the past 4 days. She had a previous history of a subtotal gastrectomy due to gastric cancer. The physical examination revealed a lower left quadrant palpable mass. Abdominopelvic CT scan showed distension of the gastric remnant with anastomotic obstruction caused by a bezoar. Attempted endoscopic dissolution of the bezoar was unsuccessful. The patient then underwent surgery enterotomy proximal to the obstruction with extraction of the mass. CLINICAL DISCUSSION: Bezoars are responsible for 0.4%-4% of cases of mechanical gastrointestinal obstruction (Dikicier et al., 2015). Contrast-enhanced CT scan is the best diagnostic test with a sensitivity and specificity of 90% and 57%, respectively (Kim et al., 2003). Treatment options differ according to the type, size and location of the bezoar as well as clinical presentation. Conservative measures such as chemical dissolution and endoscopic fragmentation and extraction can be used with surgery being usually required for a bezoar-induced gastrointestinal obstruction. CONCLUSION: The clinical findings of bezoar-induced ileus do not differ from the other different causes of mechanical intestinal obstruction. Hence, a high grade of suspicion and an early radiological exam are the keys for a prompt diagnosis and treatment.

Wilkie's Syndrome: An Unexpected Finding.

Wilkie's syndrome is a rare pathology caused by extrinsic compression of the third part of the duodenum by the superior mesenteric artery (SMA) at its origin. The symptoms are variable and non-specific consisting of postprandial abdominal pain, nausea and vomiting, early satiety, anorexia, and weight loss. A contrast-enhanced CT scan is the standard imaging modality. Surgery is reserved for severe cases or those unresponsive to pharmacological treatment. We present a case of a 66-year-old woman with a history of prolonged postprandial abdominal pain, nausea, and substantial weight loss (30 kg in four months). Laboratory tests revealed acute renal failure with hypokalemia due to severe dehydration. She underwent an abdominal-pelvic CT scan that showed enlargement of the second and third parts of the duodenum, without an identifiable cause, followed by an upper gastrointestinal (GI) endoscopy that showed a dilated duodenum until D2 and inability of progression to D3, without mucosal abnormalities. Her MRI revealed considerable gastric and proximal duodenum distension with compression of D3 by the SMA. The patient underwent a laparoscopic duodenojejunostomy with intra-operative findings consistent with the diagnosis. The procedure and the postoperative period were uneventful, and the patient was discharged on the ninth postoperative day. Gastrografin study made at day six postop showed normal progression of the oral contrast. At the outpatient reevaluation one month postop, she remained asymptomatic and with progressive weight gain. Wilkie's syndrome is a rare form of intestinal obstruction, which is commonly disregarded. Its non-specific symptoms make it a challenging diagnosis and imply a high clinical suspicion. Among the different surgical options, duodenojejunostomy presents the best outcomes.

Methylglyoxal disturbs DNA repair and glyoxalase I system in Saccharomyces cerevisiae.

Methylglyoxal (MG) is a highly reactive aldehyde able to form covalent adducts with proteins and nucleic acids, disrupting cellular functions. In this study, we performed a screening of Saccharomyces cerevisiae (S. cerevisiae) strains to find out which genes of cells are responsive to MG, emphasizing genes against oxidative stress and DNA repair. Yeast strains were grown in the YPD-Galactose medium containing MG (0.5 to 12 mM). The tolerance to MG was evaluated by determining cellular growth and cell viability. The toxicity of MG was more pronounced in the strains with deletion in genes engaged with DNA repair checkpoint proteins, namely Rad23 and Rad50. MG also impaired the growth and viability of S. cerevisiae mutant strains Glo1 and Gsh1, both components of the glyoxalase I system. Differently, the strains with deletion in genes encoding for antioxidant enzymes were apparently resistant to MG. In summary, our data indicate that DNA repair and MG detoxification pathways are keys in the control of MG toxicity in S. cerevisiae.

Cecal Perforation by a Large Gallstone: An Unusual Diagnosis.

Cholecystocolic fistulas are uncommon, with rare cases of colonic obstruction described in the literature and even rarer cases of intestinal perforation due to gallstones. We describe a case of a 73-year-old man who presented to our ED with complaints of diffuse abdominal pain, vomiting, constipation, and fever for the past week. Abdomen CT showed signs of acute perforated appendicitis. An exploratory laparotomy was proposed which revealed cecal perforation caused by a 3 cm gallstone. A right colectomy was performed with primary anastomosis, without cholecystectomy or fistula repair. The postoperative period was complicated due to an anastomotic dehiscence on day 12 with the need for a re-laparotomy with an ileotransverse colostomy confection. The patient was in the ICU care for five days and was discharged on the 13th day after the second intervention.  The clinical presentation of gallstone ileus is nonspecific and vague often leading to a delay in the diagnosis and treatment. CT scan has the best specificity and sensibility for the diagnosis but abdominal X-ray may show the pathognomonic Rigler´s triad. The surgical treatment consists of removing the gallstone with or without simultaneous cholecystectomy and fistula repair. Reports of colonic perforation due to gallstones are very scarce, which makes this a very low suspicion diagnosis. The ideal surgical approach is not established. The morbidity of these cases can reach 50%.