Hypotension caused by intravenous infusion of rifampicin and its relation to the administration schedule

It was shown in studies on animals that bolus administration of rifampicin induced hypotension whose severity depended on the rate of the antibiotic administration. When the antibiotic was administered in the 5-, 10- or 15-minute regimen in a dose of 10 mg/kg the maximum decrease in blood pressure was 44, 34 or 21% of the initial level and the maximum antibiotic concentration attained in the blood was 34.4, 27.2 or 22.6 micrograms/ml, respectively. With the infusion for 30 minutes, the maximum antibiotic concentration in the blood was 17.6 micrograms/ml and the blood pressure did not undergo any significant changes. When the rate of the antibiotic infusion was high there was pharmacokinetic heterogeneity of the blood serum and biophase which could lead to unpredictable results. After repeated administrations of rifampicin to the same animals pronounced tachyphylaxis to the antibiotic was noted, which manifested itself in decreasing of hypotension, though the serum antibiotic level was 1.5 to 2 times higher that the initial one. It was concluded that administration of rifampicin in the therapeutic dose equal to 10 mg/kg for 30 minutes was the most sparing regimen for the antibiotic bolus intravenous infusion. Gradual increase in the antibiotic dose and administration rate in patients is possible under careful control of blood pressure and pharmacokinetic studies.     

Towards Clinical Molecular Diagnosis of Inherited Cardiac Conditions: A Comparison of Bench-Top Genome DNA Sequencers

Background

Molecular genetic testing is recommended for diagnosis of inherited cardiac disease, to guide prognosis and treatment, but access is often limited by cost and availability. Recently introduced high-throughput bench-top DNA sequencing platforms have the potential to overcome these limitations.

Methodology/Principal Findings

We evaluated two next-generation sequencing (NGS) platforms for molecular diagnostics. The protein-coding regions of six genes associated with inherited arrhythmia syndromes were amplified from 15 human samples using parallelised multiplex PCR (Access Array, Fluidigm), and sequenced on the MiSeq (Illumina) and Ion Torrent PGM (Life Technologies). Overall, 97.9% of the target was sequenced adequately for variant calling on the MiSeq, and 96.8% on the Ion Torrent PGM. Regions missed tended to be of high GC-content, and most were problematic for both platforms. Variant calling was assessed using 107 variants detected using Sanger sequencing: within adequately sequenced regions, variant calling on both platforms was highly accurate (Sensitivity: MiSeq 100%, PGM 99.1%. Positive predictive value: MiSeq 95.9%, PGM 95.5%). At the time of the study the Ion Torrent PGM had a lower capital cost and individual runs were cheaper and faster. The MiSeq had a higher capacity (requiring fewer runs), with reduced hands-on time and simpler laboratory workflows. Both provide significant cost and time savings over conventional methods, even allowing for adjunct Sanger sequencing to validate findings and sequence exons missed by NGS.

Conclusions/Significance

MiSeq and Ion Torrent PGM both provide accurate variant detection as part of a PCR-based molecular diagnostic workflow, and provide alternative platforms for molecular diagnosis of inherited cardiac conditions. Though there were performance differences at this throughput, platforms differed primarily in terms of cost, scalability, protocol stability and ease of use. Compared with current molecular genetic diagnostic tests for inherited cardiac arrhythmias, these NGS approaches are faster, less expensive, and yet more comprehensive.     

Emodin Suppresses Migration and Invasion through the Modulation of CXCR4 Expression in an Orthotopic Model of Human Hepatocellular Carcinoma

Accumulating evidence(s) indicate that CXCL12-CXCR4 signaling cascade plays an important role in the process of invasion and metastasis that accounts for more than 80% of deaths in hepatocellular carcinoma (HCC) patients. Thus, identification of novel agents that can downregulate CXCR4 expression and its associated functions have a great potential in the treatment of metastatic HCC. In the present report, we investigated an anthraquinone derivative, emodin for its ability to affect CXCR4 expression as well as function in HCC cells. We observed that emodin downregulated the expression of CXCR4 in a dose-and time-dependent manner in HCC cells. Treatment with pharmacological proteasome and lysosomal inhibitors did not have substantial effect on emodin-induced decrease in CXCR4 expression. When investigated for the molecular mechanism(s), it was observed that the suppression of CXCR4 expression was due to downregulation of mRNA expression, inhibition of NF-κB activation, and abrogation of chromatin immunoprecipitation activity. Inhibition of CXCR4 expression by emodin further correlated with the suppression of CXCL12-induced migration and invasion in HCC cell lines. In addition, emodin treatment significantly suppressed metastasis to the lungs in an orthotopic HCC mice model and CXCR4 expression in tumor tissues. Overall, our results show that emodin exerts its anti-metastatic effect through the downregulation of CXCR4 expression and thus has the potential for the treatment of HCC.     

From feces to data: A metabarcoding method for analyzing consumed and available prey in a bird‐insect food web

Diets play a key role in understanding trophic interactions. Knowing the actual structure of food webs contributes greatly to our understanding of biodiversity and ecosystem functioning. The research of prey preferences of different predators requires knowledge not only of the prey consumed, but also of what is available. In this study, we applied DNA metabarcoding to analyze the diet of 4 bird species (willow tits Poecile montanus, Siberian tits Poecile cinctus, great tits Parus major and blue tits Cyanistes caeruleus) by using the feces of nestlings. The availability of their assumed prey (Lepidoptera) was determined from feces of larvae (frass) collected from the main foraging habitat, birch (Betula spp.) canopy. We identified 53 prey species from the nestling feces, of which 11 (21%) were also detected from the frass samples (eight lepidopterans). Approximately 80% of identified prey species in the nestling feces represented lepidopterans, which is in line with the earlier studies on the parids' diet. A subsequent laboratory experiment showed a threshold for fecal sample size and the barcoding success, suggesting that the smallest frass samples do not contain enough larval DNA to be detected by high‐throughput sequencing. To summarize, we apply metabarcoding for the first time in a combined approach to identify available prey (through frass) and consumed prey (via nestling feces), expanding the scope and precision for future dietary studies on insectivorous birds.     

Respiratory uncoupling in skeletal muscle delays death and diminishes age-related disease

Age-related disease, not aging per se, causes most morbidity in older humans. Here we report that skeletal muscle respiratory uncoupling due to UCP1 expression diminishes age-related disease in three mouse models. In a longevity study, median survival was increased in UCP mice (animals with skeletal muscle-specific UCP1 expression), and lymphoma was detected less frequently in UCP female mice. In apoE null mice, a vascular disease model, diet-induced atherosclerosis was decreased in UCP animals. In agouti yellow mice, a genetic obesity model, diabetes and hypertension were reversed by induction of UCP1 in skeletal muscle. Uncoupled mice had decreased adiposity, increased temperature and metabolic rate, elevated muscle SIRT and AMP kinase, and serum characterized by increased adiponectin and decreased IGF-1 and fibrinogen. Accelerating metabolism in skeletal muscle does not appear to impact aging but may delay age-related disease.     

Variations in carotenoid content and acyl chain composition in exponential,stationary and biofilm states of Staphylococcus aureus,and their influence on membrane biophysical properties

Bacteria are often found in close association with surfaces, resulting in the formation of biofilms. In Staphylococcus aureus (S. aureus), biofilms are implicated in the resilience of chronic infections, presenting a serious clinical problem world-wide. Here, S. aureus biofilms are grown under flow within clinical catheters at 37 °C. The lipid composition and biophysical properties of lipid extracts from these biofilms are compared with those from exponential growth and stationary phase cells. Biofilms show a reduction in iso and anteiso branching compensated by an increase in saturated fatty acids compared to stationary phase. A drastic reduction in carotenoid levels is also observed during biofilm formation. Thermotropic measurements of Laurdan GP and DPH polarization, show a reduction of lipid packing at 37 °C for biofilms compared to stationary phase. We studied the effects of carotenoid content on DMPG and DPPG model membranes showing trends in thermotropic behavior consistent with those observed in bacterial isolates, indicating that carotenoids participate in modulating lipid packing. Additionally, bending elastic constant (k_c) measurements using vesicle fluctuation analysis (VFA) show that the presence of carotenoids can increase membrane bending rigidity. The antimicrobial peptide Magainin H2 was less activity on liposomes composed of stationary phase compared to biofilms or exponential growth isolates. This study contributes to an understanding of how Staphylococcus aureus modulates the composition of its membrane lipids, and how those changes affect the biophysical properties of membranes, which in turn may play a role in its virulence and its resistance to different membrane-active antimicrobial agents.     

Synthesis of functionalized amino acid derivatives as new pharmacophores for designing anticancer agents

A new series of functionalized amino acid derivatives N-substituted 1-N-(tert-butoxycarbonyl)-2,2-dimethyl-4-phenyl-5-oxazolidine carboxamide (1-17) and 1-N-substituted-3-amino-2-hydroxy-3-phenylpropane-1-carboxamide (18-34) were synthesized and evaluated for their in vitro cytotoxicity against human cancer cell lines. Compound 6 has shown interesting cytotoxicity (IC₅₀ = 5.67 μm) in ovarian cancer, while compound 10 exhibited promising cytotoxicity in ovarian (IC₅₀ = 6.1 μm) and oral (IC₅₀ = 4.17 μm) cancers. These compounds could be of use in designing new anti-cancer agents.