Degradability of cross-linked polyurethanes based on synthetic polyhydroxybutyrate and modified with polylactide

In many areas of application of conventional non-degradable cross-linked polyurethanes (PUR), there is a need for their degradation under the influence of specific environmental factors. It is practiced by incorporation of sensitive to degradation compounds (usually of natural origin) into the polyurethane structure, or by mixing them with polyurethanes. Cross-linked polyurethanes (with 10 and 30%wt amount of synthetic poly([R,S]-3-hydroxybutyrate) (R,S-PHB) in soft segments) and their physical blends with poly([d,l]-lactide) (PDLLA) were investigated and then degraded under hydrolytic (phosphate buffer solution) and oxidative (CoCl2/H2O2) conditions. The rate of degradation was monitored by changes of samples mass, morphology of surface and their thermal properties. Despite the small weight losses of samples, the changes of thermal properties of polymers and topography of their surface indicated that they were susceptible to gradual degradation under oxidative and hydrolytic conditions. Blends of PDLLA and polyurethane with 30 wt% of R,S-PHB in soft segments and PUR/PDLLA blends absorbed more water and degraded faster than polyurethane with low amount of R,S-PHB

A practical laboratory method to determine ceftazidime-avibactam-aztreonam synergy in patients with New Delhi Metallo-beta-lactamase (NDM) producing Enterobacterales infection

Background: In response to infection with New Delhi Metallo-beta-lactamase (NDM) producing Enterobacterales, combination antimicrobial therapy with ceftazidime/avibactam (CAZ/AVI) plus aztreonam (ATM) has been explored. This study evaluated a practical laboratory method of testing for clinically significant synergy between CAZ/AVI+ATM in NDM producing Enterobacterales. Methods: Minimum inhibitory concentration (MIC) of clinical NDM producing isolates were determined for ATM alone and CAZ/AVI+ATM using broth dilution. Restoration of ATM breakpoint following the addition of CAZ/AVI was explored. A CAZ/AVI E-test/ATM disc method was compared to broth dilution. Results: Of 43 isolates, 33/43 (77%) isolates were ATM resistant (median [range] MIC=56 [16 – 512] mg/L). Addition of CAZ/AVI restored the ATM breakpoint (MIC <4mg/L) in 29/33 (89%) of resistant isolates. Overall, the E-test/disc method correlated with findings from broth dilution in 35/43 (81%) of cases. E-test/disc sensitivity was 77% and specificity 85%. Positive predictive value was 92% and negative predictive value 61%. Conclusion: CAZ/AVI+ATM demonstrated significant synergy in most ATM resistant NDM producing Enterobacterales. The E-test/disc method is a quick, reproducible, and reliable method of testing for clinically relevant synergy in the microbiology laboratory

Romantic Name for a Deadly Condition: Kissing Aneurysms of the Pericallosal Artery – A Case Report

Background: Kissing aneurysms are two independent but adjacent aneurysms protruding from two contralateral arterial locations. This report describes a successfully treated case of kissing aneurysms at the Department of Neurosurgery, Medical University of Gdansk. Case: A 45-year-old asymptomatic woman was diagnosed with unruptured bilateral aneurysms located in the pericallosal-callosomarginal division. Her medical history included a previous intracranial aneurysm and arterial hypertension. The patient underwent a successful treatment by surgical clipping and was discharged in good condition; neither disability nor neurologic deficit was noticed upon discharge. Surgical wound healing was complicated by an infection and resulted in a reoperation for the patient. Conclusion: The etiology of kissing aneurysms is still unknown and the best treatment method stills remains unclear. Thus, every case has to be carefully and individually assessed by an interdisciplinaryteam. As a result, patient transfer to an experienced neurosurgical center could be beneficial

Pak1 regulates focal adhesion strength, myosin IIA distribution, and actin dynamics to optimize cell migration

p21-activated kinases are essential for spatial and temporal coordination of cytoskeletal dynamics with cellular adhesion during cell migration

A Small-Molecule Inhibitor of T. gondii Motility Induces the Posttranslational Modification of Myosin Light Chain-1 and Inhibits Myosin Motor Activity

Toxoplasma gondii is an obligate intracellular parasite that enters cells by a process of active penetration. Host cell penetration and parasite motility are driven by a myosin motor complex consisting of four known proteins: TgMyoA, an unconventional Class XIV myosin; TgMLC1, a myosin light chain; and two membrane-associated proteins, TgGAP45 and TgGAP50. Little is known about how the activity of the myosin motor complex is regulated. Here, we show that treatment of parasites with a recently identified small-molecule inhibitor of invasion and motility results in a rapid and irreversible change in the electrophoretic mobility of TgMLC1. While the precise nature of the TgMLC1 modification has not yet been established, it was mapped to the peptide Val46-Arg59. To determine if the TgMLC1 modification is responsible for the motility defect observed in parasites after compound treatment, the activity of myosin motor complexes from control and compound-treated parasites was compared in an in vitro motility assay. TgMyoA motor complexes containing the modified TgMLC1 showed significantly decreased motor activity compared to control complexes. This change in motor activity likely accounts for the motility defects seen in the parasites after compound treatment and provides the first evidence, in any species, that the mechanical activity of Class XIV myosins can be modulated by posttranslational modifications to their associated light chains

p21-activated kinase signaling in breast cancer

The p21-activated kinases signal through a number of cellular pathways fundamental to growth, differentiation and apoptosis. A wealth of information has accumulated at an impressive pace in the recent past, both with regard to previously identified targets for p21-activated kinases that regulate the actin cytoskeleton and cellular stress pathways and with regard to newly identified targets and their role in cancer. Emerging data also provide new clues towards a previously unappreciated link between these various cellular processes. The present review attempts to provide a quick tutorial to the reader about the evolving significance of p21-activated kinases and small GTPases in breast cancer, using information from mouse models, tissue culture studies, and human materials

Influence of polyurethanes based on synthetic poly([R,S]-3-hydroxybutyrate) on micoorganisms growth

W pracy przedstawiono wyniki badań oddziaływania nowych alifatycznych poliuretanów (PUR), otrzymanych z udziałem ataktycznego poli([R,S]-3- hydroksymaślanu (a-PHB), na wzrost Staphylococcus aureus, Escherichia coli i Candida albicans wokół próbek polimerów. Strefa zahamowania wzrostu mikroorganizmów oznaczona została także dla handlowego, biomedycznego poliuretanu - ChronoThane T oraz dla czystego rozpuszczalnika, użytego do syntezy poliuretanów (N,N-dimetyloformamidu). Najbardziej wrażliwym na działanie materiału poliuretanowego w warunkach prowadzenia doświadczenia był szczep Staphylococcus aureus, najmniej zaś - Candida albicans. Wykluczono wpływ czystego rozpuszczalnika na wzrost mikroorganizmów. Natomiast ChronoThane T tylko w niewielkim stopniu ograniczył ich wzrost. Stwierdzono więc, że obecność poli([R,S]- 3-hydroksymaślanu w strukturze poliuretanów wpłynęła na ich właściwości biostatyczne.In the present study the influence of novel aliphatic polyurethanes (PUR), based on atactic poly([R,S]-3- hydroxybutyrate) (a-PHB), on growth of Staphylococcus aureus, Escherichia coli and Candida albicans in the area around polymer samples has been estimated. For comparison measurement of zone of inhibition was also performed for ChronoThane T – the medical grade aliphatic polyurethane and for pure solvent - N,N-dimethylformamide used in the synthesis of polyurethanes. Staphylococcus aureus was the most sensitive microorganism to polymer material in conditions of investigation whereas Candida albicans – the most resistant. The influence of pure solvent on microorganisms growth was excluded and ChronoThane T only in small degree restricted bacterial vitality so it was concluded that presence of poly([R,S]-hydroxybutyrate) in polymer structure was responsible for biostatic properties of obtained polyurethanes