Evaluation of the Radiation Shielding Properties of a Tellurite Glass System Modified with Sodium Oxide

In this study, the X-ray and gamma attenuation characteristics and optical properties of a synthesized tellurite–phosphate–sodium oxide glass system with a composition of (85 − x)TeO₂–10P₂O₅–xNa₂O mol% (where x = 15, 20, and 25) were evaluated. The glass systems we re fabricated by our research group using quenching melt fabrication. The shielding parameters of as-synthesized systems, such as the mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), effective atomic number (Z_eff), half-value layer (HVL), tenth value layer (TVL), mean free path (MFP), and effective electron density (N_eff) in a wide energy range between 15 keV and 15 MeV, were estimated using well-known PHY-X/PSD software and recently developed MIKE software. Herein, the optical parameters of prepared glasses, such as molar volume (V_M), oxygen molar volume (V_O), oxygen packing density (OPD), molar polarizability (αm), molar refractivity (R_m), reflection loss (R_L), and metallization (M), were estimated using MIKE software. Furthermore, the shielding performance of the prepared glasses was compared with that of commonly used standard glass shielding materials. The results show that the incorporation of sodium oxide into the matrix TeO₂/P₂O₅ with an optimum concentration can yield a glass system with good shielding performance as well as good optical and physical properties, especially at low photon energy.     

Age-dependent alteration in muscle regeneration: the critical role of tissue niche

Although adult skeletal muscle is composed of fully differentiated fibers, it retains the capacity to regenerate in response to injury and to modify its contractile and metabolic properties in response to changing demands. The major role in the growth, remodeling and regeneration is played by satellite cells, a quiescent population of myogenic precursor cells that reside between the basal lamina and plasmalemma and that are rapidly activated in response to appropriate stimuli. However, in pathologic conditions or during aging, the complete regenerative program can be precluded by fibrotic tissue formation and resulting in functional impairment of the skeletal muscle. Our study, along with other studies, demonstrated that although the regenerative program can also be impaired by the limited proliferative capacity of satellite cells, this limit is not reached during normal aging, and it is more likely that the restricted muscle repair program in aging is presumably due to missing signals that usually render the damaged muscle a permissive environment for regenerative activity.     

Differentiation of human adult CD34+ stem cells into cells with a neural phenotype: role of astrocytes

It has recently been reported that adult hematopoietic stem cells can differentiate into neural cells, opening new frontiers in therapy for neurodegenerative diseases. In this study, adult human hematopoietic stem cells (HSCs) were isolated via magnetic bead sorting, using a specific CD34 antibody and cultured with human astrocyte culture conditioned medium (ACM). In order to evaluate their differentiation into neurons and/or astrocytes, ACM-treated cultures were probed for the expression of several neural markers. We observed morphological modifications and, after 20 days of treatment, cell morphology displayed extending processes. Immunocytochemistry, Western blotting and RT-PCR showed the expression of neuronal markers such as neurofilaments, neuron specific enolase (NSE) and NeuN in ACM-treated HSCs cultured in poly-L-lysine-coated dishes. On the contrary, when the same ACM-treated cells were grown on a plastic substrate, they expressed high levels of glial fibrillary acidic protein (GFAP), with only weak expression of neuronal markers. Nestin, a neural progenitor cell marker, was present in treated cells, regardless of the substrate. These results demonstrate that astrocytes can generate a suitable microenvironment for inducing HSCs to differentiate into neural cells. Therefore, adult bone marrow may represent a readily accessible source of cells for treating neurodegenerative diseases.     

“Alarm-corrected” ergonomic armrest use could improve learning curves of novices on robotic simulator

Surgical Endoscopy - In robotic surgery, the professional ergonomic habit of using an armrest reduces operator fatigue and increases the precision of motion. We designed and validated a pressure...     

Midazolam does not reduce emergence delirium after sevoflurane anesthesia in children

Background: Behavioral disturbance in children following sevoflurane anesthesia is a relatively frequent event. The aim of this study was to evaluate whether a higher dose of preoperatively administered rectal midazolam compared with a lower would alleviate this phenomenon. Furthermore the impact of these two doses of midazolam on sedation at induction of anesthesia was compared. Methods: A total of 115 children presenting for minor surgery under anesthesia were included in the study. The children were randomized to receive rectally either 1 mg·kg⁻¹ midazolam (group H) or 0.5 mg·kg⁻¹ midazolam (group L). General anesthesia was induced with propofol or sevoflurane and maintained with 1.5% sevoflurane in the inspiratory limb. Prior to the start of surgery a regional block was performed to ensure adequate pain relief. Behavior on emergence was assessed using a three point scale. In case of severe agitation propofol was administered IV. Results: The children in group H were significantly better sedated preoperatively (P < 0.01). There was no significant difference in emergence behavior: 42.1% of children in group H compared with 36.2% of children in group L exhibited severe agitation requiring sedation with propofol (P = 0.37). However, regardless of the preoperative dose of midazolam more children under the age of 36 months (61.4%) were severely distressed at emergence compared with older children (16.7%) (P < 0.01). Conclusions: A higher dose of 1 mg·kg⁻¹ rectal midazolam results in much better sedated children on induction of anesthesia than 0.5 mg·kg⁻¹. This, however, does not result in a reduced incidence of emergence delirium after sevoflurane anesthesia. Regardless of the premedication negative behavioral changes occur more frequently in children younger than 3 years of age.     

Timing of CMV‐specific effector memory T cells predicts viral replication and survival after allogeneic hematopoietic stem cell transplantation

The aim of this study was to characterize timing, kinetic, and magnitude of CMV‐specific immune response after hematopoietic stem cell transplantation (HSCT) and its ability to predict CMV replication and clinical outcomes. Using cell surface and intracellular cytokine staining by flow cytometry, CMV‐specific T‐cell response was measured in blood, while CMV viral load and chimerism were determined by real‐time PCR. Patients that reconstituted CMV‐specific T‐cell response within 6 weeks after Allo‐SCT showed a more robust immune response (CD8⁺: 0.7 cells/μl vs. 0.3/μl; P‐value = 0.01), less incidence of CMV replication (33% vs. 89.5%; P‐value = 0.007), reduced viral loads (1.81 log copies/ml vs. 0 copies/ml; P‐value = 0.04), and better overall survival (72%; CI: 0.53–0.96 vs. 42% CI: 0.24–0.71; P‐value = 0.07) than patients with a delayed immune reconstitution. Viremic patients had significantly higher transplant‐related mortality than nonviremic patients after 1 year (33% CI: 0.15–0.52 vs. 0% CI: 0.05–0.34; P‐value = 0.01). Risk factors independently associated with viral replication were receptor pretransplant CMV‐positive serostatus (P‐value = 0.02) and acquiring CMV‐specific T‐cell response after 6 weeks post‐transplantation (P‐value = 0.009). In conclusion, timing of acquiring a positive CMV‐specific T‐cell immune response after transplantation may identify patients with different risk for viral replication and different clinical outcomes, including survival.     

Two Stages Conversion of Failed Laparoscopic Adjustable Gastric Banding to Laparoscopic Roux-En-Y Gastric Bypass. A Study of One Hundred Patients

Introduction

Conversion to laparoscopic gastric bypass (LRYGB) appears to be the treatment of choice after failed LAGB. To reduce the risk of postoperative complications, some surgeons routinely adopt a two-stage strategy. The purpose of this study was to analyze our institution’s experience with the two-stage procedure for LAGB conversion to LRYGB

Materials and Methods

The bariatric database of our institution was reviewed to identify patients who had undergone conversion of LAGB to LRYGB from November 2007 to June 2012.

Results

One hundred patients were included. Of these, 62 (62 %) required conversion to LRYGB for inadequate weight loss or weight regain and 38 for band-related complications. All the procedures were performed in two stages and laparoscopically. The average time between band removal and LRYGB was 17.3 months. The mean follow-up after LRYGB was 31?±?18.7 months. The mean BMI prior to LRYGB conversion was 45.3?±?5.2. Early complications occurred in 15 patients (15 %), while late complications occurred in only 3 patients (3 %). The average %EWL at 24 months and 48 months after conversion was 70.1 and 69.4 %, respectively.

Conclusion

Although a two-stage conversion strategy increases the number of operations and hospital stay without decreasing the rate of early complications compared to one-stage conversion; it has shown to be associated with low rates of GJA stenosis and excellent %EWL.     

Nifedipine Reduces the Colonic Motor Response to Eating in Patients with the Irritable Colon Syndrome

Patients with the irritable colon syndrome have an exaggerated and/or prolonged colonic motor response to eating. This is believed to be the cause of their postprandial complaints. Since the flux of calcium ions across cell membranes plays a major role in the contractions of the gastrointestinal smooth muscle, we investigated the effect of nifedipine, a calcium channel blocker, on the gastrocolonic response in nine patients with the irritable colon syndrome. Colonic myoelectric and contractile activity was recorded during fasting and after a 1000-cal mixed meal, either with or without nifedipine (20 mg sublingually) administration. Nifedipine reduced the postprandial increase of both spike potential activity and motility index. This effect of acute administration of the drug provides rational support to test nifedipine in clinical trials as a possible means for treating the irritable colon syndrome.