Effect of gap junction uncoupler heptanol on resistance arteries reactivity in experimental models of diabetes, hyperlipemia and hyperlipemia-diabetes

The understanding of the involvement of the gap junctions (GJ) in the vascular reactivity is an ongoing effort. In this study we questioned on impact of pathologies such as diabetes, hyperlipemia, and simultaneous hyperlipemia-diabetes on GJ involvement in the contractile/relaxant response of the mesenteric resistance arteries. To this purpose, four groups of Golden Syrian hamsters were used: (i) diabetics (D), injected by streptozotocin, (ii) hyperlipemics (H), fed the standard chow of the species supplemented with 3% cholesterol and 15% butter, (iii) simultaneously hyperlipemic-diabetics (HD), and (iv) controls (C), age-matched normal healthy animals. At 24 weeks after the beginning of the experiment, the vascular reactivity of the resistance arteries was measured by the myograph technique in the presence/absence of 1 mM Heptanol (Hep) and of vasoconstrictors and vasodilators. The results showed that: (i) in pathological conditions 1 mM Hep significantly impaired the constrictor response of the hamster resistance arteries to both 10(-5) M NA (noradrenaline, agonist of alpha(1)-adrenoceptors) and 64.1 mM K+ (potassium ion, the major intracellular cation). The impairment occur in the group range: HD < H < D < C being the highest at the simultaneous insult of hyperlipemia and diabetes; (ii) independently of the pathological condition, 1 mM Hep abolishes both endothelium-dependent and independent relaxation of the hamster resistance arteries. At 1 mM Hep we noticed a reversible effect on endothelium-dependent relaxation that may be partially restored (in normal) in the presence of L-arginine. It is hoped that these results may contribute to understanding of the involvement of GJ in vascular pathology/dysfunction.     

Optic nerve bilateral atrophy in a suprachiasmatic astrocytoma

The paper presents a clinical case of a 5 years old child with bilateral optic atrophy and the specific diagnosis and treatment problems of this case. The image investigations have a major part in establishing the positive diagnosis: computerized tomography, magnetic resonance imaging and the elective treatment belongs to the field of neurosurgery.     

Volcanic Tuff as Secondary Raw Material in the Production of Clay Bricks

The present work examines an innovative manufacturing technique for fired clay bricks, using tuff as a secondary raw material. Samples were made of clay and tuff (0–30 wt.%) fired at 900 to 1100 °C. The chemical and mineralogical compositions and physical and thermal analyses of raw materials were investigated by using SEM-EDS, RX and DTA-TG curves. The samples were analysed from the mineralogical, technological and mechanical points of view. The result show that the tuff’s presence in the clay mixtures considerably reduced the shrinkage of the product during the firing process, and the manufactured samples were of excellent quality. The compressive strength of the bricks varied from 5–35.3MPa, being influenced by the tuff content, clay matrix properties and firing temperatures. Finally, the heat demand for increasing the temperature from room to the firing temperature of the sample with 10% tuff content was 22%.     

Food Habits and Lifestyle of Romanians in the Context of the COVID-19 Pandemic

The pandemic caused by the SARS-CoV-2 virus has produced significant changes in socio-cultural life, diet, and interpersonal relationships across the world’s population. The present study aims to identify changes in lifestyle and diet among the Romanian population one year after the onset of the COVID-19 pandemic. An online questionnaire with 58 items (addressing the following aspects: socio-demographic and anthropometric data, current eating habits, and lifestyle changes) was distributed using institutional mailing lists and social media. A total number of 2040 respondents participated in the study, of whom 1464 were women, and 576 men. Among the respondents, 1598 came from urban areas and 442 from rural areas. The processing of the collected data showed significant changes in the behavior of the respondents caused by the pandemic situation with psycho-affective changes in some cases. The number of people who had anxiety, depression and nervousness increased by up to 20%. The majority of respondents (over 57%) were up to 30 years old, either students (43.50%) or employees going to workplaces (33.20%). Analyzing eating habits, we found that diet modification was needed to increase the daily consumption of fruits, vegetables, fish, and seafood. Regarding weight status during the pandemic, we noticed that 34.7% of normal-weight respondents said that they gained weight while 49.7% of overweight people and 52.5% of obese people said that they gained weight (p < 0.0001). Regarding psycho-emotional behavior, 11.81% of the surveyed women stated that they frequently had depressive states during the pandemic period and 11.63% of the men stated that they frequently presented depressive states during the pandemic (p = 0.005).     

Characterization of Titanium Alloy Obtained by Powder Metallurgy

Ti-based alloys are an important class of materials suitable especially for medical applications, but they are also used in the industrial sector. Due to their low tribological properties it is necessary to find optimal technologies and alloying elements in order to develop new alloys with improved properties. In this paper, a study on the influence of sintering treatments on the final properties of a titanium alloy is presented. The alloy of interest was obtained using the powders in following weight ratio: 80% wt Ti, 8% wt Mn, 3% wt Sn, 6% wt Aluminix123, 2% wt Zr and 1% wt graphite. Two sintering methods were used, namely two-step sintering (TSS) and multiple-step sintering (MSS), as alternatives to conventional sintering which uses a single sintering dwell time. Evolution of sample morphology, composition and crystalline structure with sintering method was evidenced. The lower values for the friction coefficient and for the wear rate was attained in the case of the sample obtained by TSS.     

High-resolution crystal structure reveals molecular details of target recognition by bacitracin

Bacitracin is a metalloantibiotic agent that is widely used as a medicine and feed additive. It interferes with bacterial cell-wall biosynthesis by binding undecaprenyl-pyrophosphate, a lipid carrier that serves as a critical intermediate in cell wall production. Despite bacitracin’s broad use, the molecular details of its target recognition have not been elucidated. Here we report a crystal structure for the ternary complex of bacitracin A, zinc, and a geranyl-pyrophosphate ligand at a resolution of 1.1 Å. The antibiotic forms a compact structure that completely envelopes the ligand’s pyrophosphate group, together with flanking zinc and sodium ions. The complex adopts a highly amphipathic conformation that offers clues to antibiotic function in the context of bacterial membranes. Bacitracin’s efficient sequestration of its target represents a previously unseen mode for the recognition of lipid pyrophosphates, and suggests new directions for the design of next-generation antimicrobial agents.     

Sim one, do one, teach one: considerations in designing training curricula for surgical simulation

Although there is considerable interest in the use of simulation for the acquisition of fundamental surgical skills through goal-directed practice in a safe environment, there is little evidence guiding educators on how best to implement simulation within surgical skills curricula. This article reviews the application of the expert performance model in surgery and the role of simulation in surgical skills acquisition. The focus is on implementation of deliberate practice, highlighting the principles of part-task training, proficiency-based training and overtraining. With resident and educator time at a premium, the identification of an optimally effective and efficient training strategy has significant implications for how surgical skills training is incorporated into residency programs, which is critical in today's environment.     

Arterial wave reflections and mortality in haemodialysis patients--only relevant in elderly, cardiovascularly compromised?

BACKGROUND: Chronic kidney disease (CKD) patients have a 3-30-fold increased risk of death compared with the general population. This mortality difference is even more pronounced in younger subjects. Two markers of aortic stiffness--aortic pulse wave velocity (PWV) and augmentation index (AIx)--have been prospectively related to all-cause and cardiovascular (CV) mortality in end-stage renal disease (ESRD) populations. The aims of our study were first, to confirm the important deleterious effect of arterial stiffness in uraemia and second, to assess the impact on survival of increased AIx in a relatively young non-diabetic dialysis population, with minimal CV disease. METHODS: Ninety-two patients (mean age 42.6 +/- 11.2 years) were included in the study and followed for a period of 61 +/- 25 months. None of the patients had diabetes mellitus, and only 3.3% had prior history of CV disease. AIx was determined by applantation tonometry using a SphygmoCor device (AtCor, PWV Inc., Westmead, Sydney, Australia). RESULTS: Mean AIx in our study population was 19.9 +/- 13.7%; other significant haemodynamic parameters were: systolic blood pressure (SBP) 129 +/- 24 mmHg, pulse pressure 35.3 +/- 17.5 mmHg with 27.2% of the study population receiving angiotensin-converting enzyme inhibitors (ACE-I). On univariate analysis, in our group AIx correlated with: body weight (P < 0.001), radial SBP (P < 0.001) and haemoglobin levels (P < 0.05). There was no correlation between AIx and any of the echocardiographic parameters. In the stepwise multiple regression analysis, the only independent predictors for AIx were weight (P < 0.001), SBP (P < 0.001) and haemoglobin (P < 0.05) with the model explaining 33% of the AIx variability (adjusted R(2) = 0.33). During the follow-up period, 15 deaths were recorded. In the Cox analysis (P = 0.014; chi square 20.7 for the model) the only independent predictors for all-cause mortality were age (P = 0.001), left ventricular mass index (P = 0.032) and ACE-I therapy (P = 0.039) while AIx did not reach statistical significance. There was no difference in patients' survival when divided by AIx tertiles, assessed by the log rank test (P = 0.78). CONCLUSION: Our results fail to support the notion that an increased effect of wave reflections on central arteries is a strong and independent predictor of mortality in all ESRD patients on haemodialysis. The effect of arterial wave reflections might be in fact dependent on patient age and concurrent comorbidity status.