Acute stress differentially affects corticotropin-releasing hormone mRNA expression in the central amygdala of the "depressed" flinders sensitive line and the control flinders resistant line rats

Preclinical and clinical evidence suggests that neuropeptides play a role in the pathophysiology of mood disorders. In the present study, we investigated the involvement of the peptides corticotropin-releasing hormone (CRH), neuropeptide Y (NPY) and nociceptin/orphanin FQ (N/OFQ) and of their receptors in the regulation of emotional behaviours. In situ hybridization experiments were performed in order to evaluate the mRNA expression levels of these neuropeptidergic systems in limbic and limbic-related brain regions of the Flinders Sensitive Line (FSL) rats, a putative genetic animal model of depression. The FSL and their controls, the Flinders Resistant Line (FRL) rats, were subjected to one hour acute restraint and the effects of the stress exposure, including possible strain specific changes on these neuropeptidergic systems, were studied. In basal conditions, no significant differences between FSL and FRL rats in the CRH mRNA expression were found, however an upregulation of the CRH mRNA hybridization signal was detected in the central amygdala of the stressed FRL, compared to the non stressed FRL rats, but not in the FSL, suggesting a hypoactive mechanism of response to stressful stimuli in the "depressed" FSL rats. Baseline levels of NPY and N/OFQ mRNA were lower in the FSL rats compared to the FRL in the dentate gyrus of hippocampus and in the medial amygdala, respectively. However, the exposure to stress induced a significant upregulation of the N/OFQ mRNA levels in the paraventricular thalamic nucleus, while in the same nucleus the N/OFQ receptor mRNA expression was higher in the FSL rats. In conclusion, selective alterations of the NPY and N/OFQ mRNA in limbic and limbic-related regions of the FSL rats, a putative animal model of depression, provide further support for the involvement of these neuropeptides in depressive disorders. Moreover, the lack of CRH activation following stress in the "depressed" FSL rats suggests a form of allostatic load, that could alter their interpretation of environmental stimuli and influence their behavioural response to stressful situations.     

Epidemiological considerations in sudden hearing loss: a study of 183 cases

Summary We have studied certain epidemiological problems not often encountered in the literature, involving patients with sudden hearing loss. We performed a retrospective cross-sectional study on 183 patients at the University of Padova and found that: (a) age at the onset of the hearing loss incurred is closely associated with the presence of concomitant diseases; (b) partial or total recovery of hearing is strongly predicated by the variables of age at onset and the interval between onset of hearing loss and the beginning of treatment given. We have also used polar-coordinate diagrams to show that cases of sudden hearing loss tend to be cyclic and are more prevalent in the central months of each season.     

Production of Transforming Growth Factor Alpha by Hamster Eosinophils

Previously it was demonstrated that malignant transformation of the Syrian hamster cheek pouch mucosa is associated with the expression of TGF-alpha. Therefore in situ hybridization and immunohistochemistry was used to investigate the cellular sources of TGF-alpha production in this model system. Surprisingly one cell type in the inflammatory infiltrate present in the connective tissue adjacent to the transformed epithelium represented a major source of TGF-alpha mRNA. Detailed analysis of these cells revealed that they were eosinophils. In addition to TGF-alpha mRNA, about 40% of the eosinophils associated with the oral tumors exhibited TGF-alpha product reactive with a monoclonal antibody against the C terminus of the mature TGF-alpha peptide. Normal hamster bone marrow eosinophils also exhibited TGF-alpha mRNA and product by in situ hybridization and immunohistochemistry. These results suggest that the eosinophil represents a biologically significant source of TGF-alpha.     

Lack of inducible nitric oxide synthase leads to increased hepatic apoptosis and decreased fibrosis in mice after chronic carbon tetrachloride administration

The role of nitric oxide (NO) in liver injury and fibrosis is unclear. The purpose of this study was to determine whether inducible NO synthase deficiency (iNOS(-/-)) affects liver injury and fibrosis produced in mice by chronic carbon tetrachloride (CCl(4)) administration. Wild-type (WT) or iNOS(-/-) mice were subjected to biweekly CCl(4) injections over 8 weeks, whereas controls were given isovolumetric injections of olive oil. Serum aminotransferases were lower after CCl(4) in the iNOS(-/-) than in the WT mice, which correlated with decreased necrosis on liver histology. There was increased apoptosis, a lower number of stellate cells, and a lesser degree of fibrosis after CCl(4) in the iNOS(-/-) as compared with the WT mice. alpha(1)(I) collagen messenger RNA (mRNA) was markedly increased after CCl(4) in the WT and to a significantly lesser extent in the iNOS(-/-) mice. Liver matrix metalloproteinase-9 (MMP-9) mRNA and MMP-2 mRNA were increased more in the WT than in the iNOS(-/-) mice after CCl(4). Also tissue inhibitor metalloproteinase 1 (TIMP-1) mRNA was increased to a much greater extent in the WT than in the iNOS(-/-) mice after CCl(4) (P < 0.05). However, MMP-9 and TIMP-1 protein, determined by western blot, were similarly increased after CCl(4) in both groups of mice. CONCLUSION: NO protects against CCl(4)-induced apoptosis. In the absence of iNOS, there is decreased necrosis, increased apoptosis, and reduced liver fibrosis.     

Multiple Mutations Associated with Emergent Variants Can Be Detected as Low-Frequency Mutations in Early SARS-CoV-2 Pandemic Clinical Samples

Genetic analysis of intra-host viral populations provides unique insight into pre-emergent mutations that may contribute to the genotype of future variants. Clinical samples positive for SARS-CoV-2 collected in California during the first months of the pandemic were sequenced to define the dynamics of mutation emergence as the virus became established in the state. Deep sequencing of 90 nasopharyngeal samples showed that many mutations associated with the establishment of SARS-CoV-2 globally were present at varying frequencies in a majority of the samples, even those collected as the virus was first detected in the US. A subset of mutations that emerged months later in consensus sequences were detected as subconsensus members of intra-host populations. Spike mutations P681H, H655Y, and V1104L were detected prior to emergence in variant genotypes, mutations were detected at multiple positions within the furin cleavage site, and pre-emergent mutations were identified in the nucleocapsid and the envelope genes. Because many of the samples had a very high depth of coverage, a bioinformatics pipeline, “Mappgene”, was established that uses both iVar and LoFreq variant calling to enable identification of very low-frequency variants. This enabled detection of a spike protein deletion present in many samples at low frequency and associated with a variant of concern.