Vascular effects of midazolam, flumazenil, and a novel imidazobenzodiazepine MP-III-058 on isolated rat aorta

Hypotensive influences of benzodiazepines and other GABAA receptor ligands, recognized in clinical practice, seem to stem from the existence of "vascular" GABAA receptors in peripheral blood vessels, besides any mechanisms in the central and peripheral nervous systems. We aimed to further elucidate the vasodilatatory effects of ligands acting through GABAA receptors. Using immunohistochemistry, the rat aortic smooth muscle layer was found to express GABAA γ2 and α1-5 subunit proteins. To confirm the role of "vascular" GABAA receptors, we investigated the vascular effects of standard benzodiazepines, midazolam, and flumazenil, as well as the novel compound MP-III-058. Using two-electrode voltage clamp electrophysiology and radioligand binding assays, MP-III-058 was found to have modest binding but substantial functional selectivity for α5β3γ2 over other αxβ3γ2 GABAA receptors. Tissue bath assays revealed comparable vasodilatory effects of MP-III-058 and midazolam, both of which at 100 µmol/L concentrations had efficacy similar to prazosin. Flumazenil exhibited weak vasoactivity per se, but significantly prevented the relaxant effects of midazolam and MP-III-058. These studies indicate the existence of functional GABAA receptors in the rat aorta, where ligands exert vasodilatory effects by positive modulation of the benzodiazepine binding site, suggesting the potential for further quest for leads with optimized pharmacokinetic properties as prospective adjuvant vasodilators.

Oxidative stress status assessment of rats' brains injury following subacute exposure to K-oximes

Oxidative stress status and morphological injuries in the brain of Wistar rats induced by repeated application of selected acetylcholinesterase reactivators - asoxime, obidoxime, K027, K048, K074, and K075 were evaluated. Each oxime in a dose of 0.1 of LD50/kg im was given 2x/week for 4 weeks. Markers of lipid peroxidation (malondialdehyde, MDA), and protein oxidation (advanced oxidation protein products, AOPP), as well as the activity of antioxidant enzymes (catalase, CAT, superoxide dismutase, SOD, glutathione reductase, GR, and glutathione peroxidase, GPx), were estimated in the brain tissue homogenates on day 35 of the study. Brain alterations were carefully quantified by semiquantitative grading scales - brain damage score (BDS). Oxidative stress parameters, MDA and AOPP were significantly highest in the asoxime-, obidoxime- and K075-treated groups (p < 0.001). The activity of SOD and CAT was significantly elevated in the obidoxime-, K048-, and K075-treated groups (p < 0.001). Besides, GR was markedly decreased in the obidoxime- and K074-treated groups (p < 0.01), while treatment with K048, K074 and K075 induced extremely high elevation in GPx levels (p < 0.001). In the same groups of rats, brain alterations associated with polymorphonuclear cell infiltrate were significantly more severe than those observed in animals receiving only asoxime or K027 (p < 0.001). The presented results confirmed that treatment with different oximes significantly improved the oxidative status and attenuated signs of inflammation in rats' brains. Presented results, together with our previously published data can help to predict likely adverse systemic toxic effects, and target organ systems, which are crucial for establishing risk categories, as well as in dose selection of K-oximes as drug candidates.

Clinicopathological Characteristics, Treatment Patterns, and Outcomes in Patients with Laryngeal Cancer

BACKGROUND

Various factors can affect the survival of patients with laryngeal cancer (LC). In this retrospective study, we assessed clinicopathological features, their prognostic value, and treatment modalities for patients with confirmed squamous cell LC.

METHODS

We collected patient data on demographics, clinicopathological characteristics, treatment patterns, and outcomes. The primary endpoints were overall survival (OS), disease-specific survival (DSS), disease-free survival (DFS), and locoregional control (LRC). We assessed survival using the Kaplan-Meier method and Cox regression model analyses of potential prognostic parameters.

RESULTS

After a median follow-up of 76 months, 28 (33.3%) patients had a recurrence. The median OS was 78 months, with an event recorded in 50% of patients. The DSS median was not reached (NR) with a survival rate of 72.6%, the DFS survival rate was 66.7% with median NR, and the LRC survival rate was 72.6% with median NR. After conducting a multivariate analysis of significant variables, we found that only recurrence and lymphatic invasion had an independent effect on OS and recurrence in DSS, while subsite impacted DFS and LRC.

CONCLUSIONS

Survival trends were consistent with other studies, except for OS. Recurrence, lymphatic invasion, and subsite location were significant factors that impacted patient survival.

Effect of hydrogen sulphide containing mineral water on experimental osteoporosis in rats

Background/Aim: Sulphur mineral water is widely used in the treatment of musculoskeletal diseases. Hydrogen sulphide is an important regulator of bone metabolism and its application in the treatment of osteoporosis is intensively researched. The aim of this study was to analyse biochemical and histological effects of H2S containing mineral water of "Mlječanica" spring on ovariectomy-induced experimental osteoporosis in rats. Methods: In this experiment a 14-week-old Wistar female rats were used. The animals undergone bilateral ovariectomy (OVX groups) as an experimental model for oestrogen-deficient osteoporosis. After six weeks, animals were divided into control and the experimental group. Rats from the experimental group treated with H2S (SW group) containing mineral water ad libitum during five weeks. Biochemical parameters for monitoring sulphur water effects were concentration in serum of osteocalcin, alkaline phosphatase, calcium and phosphorus. Histological analyses of the left tibia coloured with haematoxylin-eosin were carried out. Results: Regarding the biochemical parameters, a statistically significant increase was observed in the OVX group for osteocalcin, alkaline phosphatase calcium and phosphorus compared to the sham-operated (CNT) group (p < 0.01). In SW + OVX, alkaline phosphatase was statistically significantly decreased (p < 0.01) and serum osteocalcin and phosphorus increased (p < 0.01). Calcium values were increased without significance. In the OVX + SW group, histological analyses showed numerous osteoblasts along the trabecular endosteum and the growth of young chondrocytes in the central bone zone and their migration to the peripheral parts. Conclusion: Drinking the H2S containing "Mlječanica" mineral water has led to decreased alkaline phosphatase, increased osteocalcin and phosphorus concentration in serum and stimulated the bone reparation in osteoporotic rats.

Protective Effects of Simvastatin on Endotoxin-Induced Acute Kidney Injury through Activation of Tubular Epithelial Cells' Survival and Hindering Cytochrome C-Mediated Apoptosis

Increasing evidence suggests that apoptosis of tubular cells and renal inflammation mainly determine the outcome of sepsis-associated acute kidney injury (AKI). The study aim was to investigate the molecular mechanism involved in the renoprotective effects of simvastatin in endotoxin (lipopolysaccharide, LSP)-induced AKI. A sepsis model was established by intraperitoneal injection of a single non-lethal LPS dose after short-term simvastatin pretreatment. The severity of the inflammatory injury was expressed as renal damage scores (RDS). Apoptosis of tubular cells was detected by Terminal deoxynucleotidyl transferase-mediated dUTP Nick End Labeling (TUNEL assay) (apoptotic DNA fragmentation, expressed as an apoptotic index, AI) and immunohistochemical staining for cleaved caspase-3, cytochrome C, and anti-apoptotic Bcl-xL and survivin. We found that endotoxin induced severe renal inflammatory injury (RDS = 3.58 ± 0.50), whereas simvastatin dose-dependently prevented structural changes induced by LPS. Furthermore, simvastatin 40 mg/kg most profoundly attenuated tubular apoptosis, determined as a decrease of cytochrome C, caspase-3 expression, and AIs (p  <  0.01 vs. LPS). Conversely, simvastatin induced a significant increase of Bcl-XL and survivin, both in the strong inverse correlations with cleaved caspase-3 and cytochrome C. Our study indicates that simvastatin has cytoprotective effects against LPS-induced tubular apoptosis, seemingly mediated by upregulation of cell-survival molecules, such as Bcl-XL and survivin, and inhibition of the mitochondrial cytochrome C and downstream caspase-3 activation.

Simvastatin Inhibits Endotoxin-Induced Apoptosis in Liver and Spleen Through Up-Regulation of Survivin/NF-κB/p65 Expression

Endotoxemia is associated by dysregulated apoptosis of immune and non-immune cells. We investigated whether simvastatin has anti-apoptotic effects, and induces hepatocytes and lymphocytes survival signaling in endotoxin-induced liver and spleen injuries. Wistar rats were divided into the groups pretreated with simvastatin (20 or 40 mg/kg, orally) prior to a non-lethal dose of lipopolysaccharide (LPS), the LPS group, and the control. The severity of tissue inflammatory injuries was expressed as hepatic damage scores (HDS) and spleen damage scores (SDS), respectively. The apoptotic cell was detected by TUNEL (Terminal deoxynucleotidyl transferase dUTP Nick End Labeling) and immunohistochemical staining (expression of cleaved caspase-3, and anti-apoptotic Bcl-xL, survivin and NF-κB/p65). Simvastatin dose-dependently abolished HDS and SDS induced by LPS (p < 0.01), respectively. Simvastatin 40 mg/kg significantly decreased apoptotic index and caspase-3 cleavage in hepatocytes and lymphocytes (p < 0.01 vs. LPS group, respectively), while Bcl-XL markedly increased accordingly with simvastatin doses. In the simvastatin, groups were determined markedly increased cytoplasmic expression of survivin associated with nuclear positivity of NF-κB, in both hepatocytes and lymphocytes (p < 0.01 vs. LPS group). Cell-protective effects of simvastatin against LPS seemed to be mediated by up-regulation of survivin, which leads to reduced caspase-3 activation and inhibition of hepatocytes and lymphocytes apoptosis.

Simvastatin Protects Cardiomyocytes Against Endotoxin-induced Apoptosis and Up-regulates Survivin/NF-κB/p65 Expression

This study is aimed to investigate whether simvastatin induces cardiomyocytes survival signaling in endotoxin (lipopolysaccharide, LSP)-induced myocardial injury, and if so, further to determine a role of survivin in simvastatin-anti-apoptotic effect. Wistar rats were pretreated with simvastatin (10–40 mg/kg po) before a single non-lethal dose of LPS. In myocardial tissue, LPS induced structural disorganization of myofibrils with significant inflammatory infiltrate (cardiac damage score, CDS = 3.87 ± 0.51, p < 0.05), whereas simvastatin dose-dependently abolished structural changes induced by LPS (p < 0.01). Simvastatin in 20 mg/kg and 40 mg/kg pretreatment, dose dependently, attenuated myocardial apoptosis determined as apoptotic index (28.8 ± 4.5% and 18.9 ± 3.5, p < 0.05), decreased cleaved caspase-3 expression (32.1 ± 5.8%, p < 0.01), along with significant Bcl-xL expression in the simvastatin groups (p < 0.01). Interestingly, in the simvastatin groups were determined significantly increased expression of survivin (p < 0.01), but in negative correlation with cleaved caspase-3 and apoptotic indices (p < 0.01). Simvastatin has a cardioprotective effects against LPS induced apoptosis. The effect may be mediated by up-regulation of survivin via activation of NF-κB, which leads to reduced activation of caspase-3 and consequent apoptosis of cardiomyocytes in experimental sepsis.

Developmental Changes of Lymphoid Tissue in the Harderian Gland of Laying Hens

The Harderian gland of 110 laying hens was histologically investigated from the time of hatching to the period of 10 months of age. Tissue sections were stained with haematoxylin and eosin, periodic acid-schiff (PAS) and methyl green-pyronin technique. The research shows that lymphoid tissue is colonised by three types of cells: heterophils, lymphocytes and plasma cells. The number of these cells is directly dependent on the bird’s age. During the lifetime of the hens there gradually comes a shift in the dominance of these three cell types. Lymphoid nodules are detected only in 40-day-old chickens, while later in adult birds the Harderian gland is the organ which contains the largest number of mature plasma cells. Some plasma cells contain Russell bodies with different size and shape.