Modeling of relationships between pharmacokinetics and blockade of agonist-induced elevation of intraurethral pressure and mean arterial pressure in conscious dogs treated with alpha(1)-adrenoceptor antagonists.

Fiduxosin is a new alpha(1)-adrenoceptor antagonist targeted for the treatment of symptomatic benign prostatic hyperplasia. The purpose of this study was to determine and compare the potencies of the alpha(1)-adrenoceptor antagonists terazosin, doxazosin, tamsulosin, and fiduxosin, based on relationships between plasma drug concentrations and blockade of phenylephrine (PE)-induced intraurethral (IUP) and mean arterial pressure (MAP) responses after single oral dosing in conscious male beagle dogs. Magnitude of blockade and plasma concentrations were evaluated at selected time points over 24 h. All drugs produced dose-dependent antagonism of PE-induced IUP and MAP responses. When IUP and MAP blockade effects were plotted against drug plasma concentrations, direct relationships were observed that were well described by the sigmoidal maximal effect model. IUP IC(50) values for terazosin, doxazosin, tamsulosin, and fiduxosin were 48.6, 48.7, 0.42, and 261 ng/ml, respectively. MAP IC(50) values were 12.2, 13.8, 1.07, and 1904 ng/ml, respectively. Uroselectivity index values, defined as MAP IC(50)/IUP IC(50), were 0.25, 0.28, 2.6, and 7.3, respectively. These results extend previous observations with terazosin in this model, showing that doxazosin exhibits a uroselectivity index comparable to terazosin, consistent with the lack of alpha(1)-adrenoceptor subtype selectivity or uroselectivity of these drugs. Tamsulosin, an alpha(1a)-/alpha(1d)-subtype selective agent, had an index value approximately 10-fold greater than the nonselective drugs. Based on its pharmacokinetic profile and a relative uroselectivity 29-fold greater than the nonselective drugs, fiduxosin is expected to exhibit greater selectivity for urethral compared with vascular alpha(1)-adrenoceptors in human and should be a novel, long-acting, uroselective alpha(1)-adrenoceptor antagonist.     

The synthesis and localization of alternatively spliced fibronectin EIIIB in resting and thrombin-treated megakaryocytes

There are several species of alternatively spliced fibronectin (FN). One of these, FN EIIIB, is primarily present in embryonic and in proliferating and migrating cells and is believed to be important for cell maturation. We have studied the synthesis, localization, and secretion of this FN isoform in isolated guinea pig megakaryocytes, nonmegakaryocytic bone marrow cells, and platelets. There was 7.5 times more general FN in megakaryocytes than in nonmegakaryocytic cells based on the analysis of equivalent amounts of protein. FN EIIIB was detected by Western blotting in megakaryocytes but not in nonmegakaryocytic cells present in bone marrow. Neither megakaryocytes nor platelets secreted FN EIIIB, while megakaryocytes secreted 25.3% +/- 4.6% general FN and platelets secreted about 61% general FN in response to thrombin. Analysis of immunostained cells by confocal microscopy revealed that FN EIIIB had been redistributed to the surface of megakaryocytes in response to thrombin. Synthesis was studied by metabolic labeling, and megakaryocytes were shown to synthesize FN and FN EIIIB. Thus, megakaryocytes and platelets are among a small number of adult cells and tissues that synthesize and contain FN EIIIB. The expression of FN EIIIB on the megakaryocyte surface may influence migration and maturation.     

Enhanced electron transfer mediated detection of hydrogen peroxide using a silver nanoparticle–reduced graphene oxide–polyaniline fabricated electrochemical sensor

The current study aims at the development of an electrochemical sensor based on a silver nanoparticle–reduced graphene oxide–polyaniline (AgNPs–rGO–PANI) nanocomposite for the sensitive and selective detection of hydrogen peroxide (H₂O₂). The nanocomposite was fabricated by simple in situ synthesis of PANI at the surface of rGO sheet which was followed by stirring with AEC biosynthesized AgNPs to form a nanocomposite. The AgNPs, GO, rGO, PANI, rGO–PANI, and AgNPs–rGO–PANI nanocomposite and their interaction were studied by UV-vis, FTIR, XRD, SEM, EDX and XPS analysis. AgNPs–rGO–PANI nanocomposite was loaded (0.5 mg cm⁻²) on a glassy carbon electrode (GCE) where the active surface area was maintained at 0.2 cm² for investigation of the electrochemical properties. It was found that AgNPs–rGO–PANI–GCE had high sensitivity towards the reduction of H₂O₂ than AgNPs–rGO which occurred at −0.4 V vs. SCE due to the presence of PANI (AgNPs have direct electronic interaction with N atom of the PANI backbone) which enhanced the rate of transfer of electron during the electrochemical reduction of H₂O₂. The calibration plots of H₂O₂ electrochemical detection was established in the range of 0.01 μM to 1000 μM (R² = 0.99) with a detection limit of 50 nM, the response time of about 5 s at a signal-to-noise ratio (S/N = 3). The sensitivity was calculated as 14.7 μA mM⁻¹ cm⁻² which indicated a significant potential as a non-enzymatic H₂O₂ sensor.

The current study aims at the development of an electrochemical sensor based on a silver nanoparticle–reduced graphene oxide–polyaniline (AgNPs–rGO–PANI) nanocomposite for the sensitive and selective detection of hydrogen peroxide (H₂O₂).     

Divergent outcomes of gut microbiota alteration upon use of spectrum antibiotics in high sugar diet-induced diabetes in rats

Background: A sugar rich diet induces inflammation and insulin resistance (IR) mainly through gut microbiota alteration. Gut dysbiosis increases lipopolysaccharide (LPS) and reduces propionate and butyrate levels to impair the insulin signalling cascades by different molecular pathways, which progresses into IR. The present study was designed to investigate the effect of spectrum specific antibiotics on the modulation of gut microbiota and its signalling pathways to prevent diet-induced diabetes. Methods: Healthy male Wistar rats were divided into a non-diabetic group with a control diet (CD), a diabetic group with a high sucrose diet (HSD) and two antibiotic fed groups (linezolid and cefdinir; administered by oral gavage) along HSD. Physiological, biochemical, inflammatory and microbiome parameters were examined. Results: Cefdinir administration in HSD rats reduced fasting glucose, serum triglyceride, and cholesterol levels compared to HSD alone. In addition, cefdinir reduced serum LPS by decreasing the population of Gram-negative phyla, that is, Bacteroidetes and Proteobacteria in the fecal content. Furthermore, cefdinir treatment decreased hepatic/ileal/colonic Tlr4, Nlr1, and Nf-κB at the mRNA level. Moreover, cefdinir-treated rats had shown increased fecal butyrate and propionate and reduced acetate levels compared to HSD alone. Cefdinir treatment also induced ileal/colonic Gpr43 and Glut4 at the mRNA level after 12 weeks of administration. Conclusions: Taken together, these data suggest that administration of a Gram-negative spectrum antibiotic, that is, cefdinir, has modulated the gut microbiota, and reduced serum LPS and triglycerides, which prevented the progression of IR and inflammation in HSD rats.

A sugar rich diet induces inflammation and insulin resistance (IR) mainly through gut microbiota alteration.     

Young red blood cells; observations about the cytometric and morphologic alterations in the beginning of their life

Summary A recently described separation technique consisting of a combination of counterflow centrifugation and subsequent density (Percoll) scparation was tested for its ability to enrich red cell populations with young cells in comparison to either separation technique alone. The relative age of every fraction was determined by HbAlc measurements, resulting in the lowest HbAlc for the combination method. Conventional reticulocyte counting and floweytometric counting with thiazole orange indicated that in the youngest fractions the combination method showed the highest reticulocyte counts. There was a good correlation between manual and flowcytometric counting results. Radio-iron studies showed a two-fold enrichment with young cells in the fraction with the lowest HbAIc acquired by the combination technique in comparison to the other two methods. Cytometric measurements showed that the fractions with the lowest HbAlc were the ones with the highest MCV and MCH and the lowest MCHC. Besides loss of their RNA-material, young cells already seem to loose water and haemoglobin like older cells, resulting in a decrease of MCV and MCH and in increase in MCHC. It is concluded that combining counterflow centrifugation with subsequent density fractionation results in superior enrichment with young cells in comparison to the results of each method alone.