Biomedical Ti–Mo Alloys with Surface Machined and Modified by Laser Beam: Biomechanical,Histological, and Histometric Analysis in Rabbits

Purpose: In vivo bone response was assessed by removal torque, hystological and histometrical analysis on a recently developed biomedical Ti‐15Mo alloy, after surface modification by laser beam irradiation, installed in the tibia of rabbits. Materials and Methods: A total of 32 wide cylindrical Ti‐15Mo dental implants were obtained (10 mm × 3.75 mm). The implants were divided into two groups: 1) control samples (Machined surface – MS) and 2) implants with their surface modified by Laser beam‐irradiation (Test samples – LS). Six implants of each surface were used for removal torque test and 10 of each surface for histological and histometrical analysis. The implants were placed in the tibial metaphyses of rabbits. Results: Average removal torque was 51.5 Ncm to MS and >90 Ncm to LS. Bone‐to‐implant‐contact percentage was significantly higher for LS implants both in the cortical and marrow regions. Conclusions: The present study demonstrated that laser treated Ti‐15Mo alloys are promising materials for biomedical application.     

Physicochemical Evaluation of Acid–Base Disorders After Liver Transplantation and the Contribution From Administered Fluids

Objectives

To analyze the mechanism of acid–base disorders in liver transplant recipients and to examine the relationship between these disorders and the fluids administered during surgery.

Methods

This prospective study in a university-affiliated hospital intensive care unit (ICU) included 52 patients admitted to the ICU from December 2009 to January 2011. We examined the contributions of inorganic ion differences, lactate, unmeasured anions, phosphate, and albumin to metabolic acidosis. In addition to laboratory variables, we collected demographic and clinical data.

Results

Metabolic acidosis (standard base excess ≤ −2.0 mmol/L) was identified in 37 (71.2%) patients during the immediate postoperative period. The inorganic ion difference was the main determinant of acidosis, accounting for −6.17 mEq/L of acidifying effect. The acidemia was attenuated mainly by the alkalinizing effect of albumin reduction, which contributed +6.03 mEq/L. There was an inverse proportional relationship between the quantity of saline solution used during surgery and the inorganic ion difference during the immediate postoperative period.

Conclusions

Hyperchloremia is the primary contributor to metabolic acidosis in liver transplant recipients. Possibly the use of chloride-rich solutions increases the incidence of this disorder.     

Laser Doppler anemometry measurements of steady flow through two bi-leaflet prosthetic heart valves

Introduction

In vitro hydrodynamic characterization of prosthetic heart valves provides important information regarding their operation, especially if performed by noninvasive techniques of anemometry. Once velocity profiles for each valve are provided, it is possible to compare them in terms of hydrodynamic performance. In this first experimental study using laser doppler anemometry with mechanical valves, the simulations were performed at a steady flow workbench.

Objective

To compare unidimensional velocity profiles at the central plane of two bi-leaflet aortic prosthesis from St. Jude (AGN 21 - 751 and 21 AJ - 501 models) exposed to a steady flow regime, on four distinct sections, three downstream and one upstream.

Methods

To provide similar conditions for the flow through each prosthesis by a steady flow workbench (water, flow rate of 17L/min. ) and, for the same sections and sweeps, to obtain the velocity profiles of each heart valve by unidimensional measurements.

Results

It was found that higher velocities correspond to the prosthesis with smaller inner diameter and instabilities of flow are larger as the section of interest is closer to the valve. Regions of recirculation, stagnation of flow, low pressure, and flow peak velocities were also found.

Conclusions

Considering the hydrodynamic aspect and for every section measured, it could be concluded that the prosthesis model AGN 21 - 751 (RegentTM) is superior to the 21 AJ - 501 model (Master Series). Based on the results, future studies can choose to focus on specific regions of the these valves.     

Phototherapy and resistance training prevent sarcopenia in ovariectomized rats

The aim of this study was to histologically and biochemically analyze the effects of light-emitting diode therapy (LEDT) associated with resistance training to prevent sarcopenia in ovariectomized rats. Forty female Wistar rats (12 months old, 295–330 g) were bilaterally ovariectomized and divided into four groups (n?=?10 per group): control–sedentary (C), resistance training (T), LEDT–sedentary (L), and LEDT plus resistance training (LT). Trained rats performed a 12-week water-jumping program (3 days per week) carrying a load equivalent to 50–80 % of their body mass strapped to their back. Depending on the group protocol, the LED device (850 nm, 100 mW, 120 J/cm², spot size 0.5 cm²) was used either as the only method or after the resistance training had been performed. The device was used in the single point contact mode (for 10 min). The irradiated region was the center of the greater trochanter of the right femur and the middle third of the rectus femoris muscle was subsequently analyzed histomorphometrically. Significant increases (p?<?0.05) were noted for the muscle volume of the T (68.1?±?19.7 %), the L (74.1?±?5.1 %), and the LT (68.2?±?11.5 %) groups compared to the C group (60.4?±?5.5 %). There were also significant increases in the concentrations of IGF-1, IL-1, and TNF-α in the muscles of the treated groups (p?<?0.05). Animals in the LT group showed a significant increase in IL-6 compared to T, L, and C groups (p?<?0.05). These findings suggest that resistance training and LEDT can prevent sarcopenia in ovariectomized rats.     

Leptin as a link between the immune system and kidney‐related diseases: leading actor or just a coadjuvant?

Food intake and nutritional status modify the physiological responses of the immune system to illness and infection and regulate the development of chronic inflammatory processes, such as kidney disease. Adipose tissue secretes immune‐related proteins called adipokines that have pleiotropic effects on both the immune and neuroendocrine systems, linking metabolism and immune physiology. Leptin, an adipose tissue‐derived adipokine, displays a variety of immune and physiological functions, and participates in several immune responses. Here, we review the current literature on the role of leptin in kidney diseases, linking adipose tissue and the immune system with kidney‐related disorders. The modulation of this adipose hormone may have a major impact on the treatment of several immune‐ and metabolic‐related kidney diseases.     

Double-masked randomized clinical trial evaluating the effect of a triclosan/copolymer dentifrice on periodontal healing after one-stage full-mouth debridement

Background: This study evaluates the effect of triclosan/copolymer dentifrice on the 6‐month clinical response of patients with generalized severe chronic periodontitis (GSCP) treated with one‐stage, full‐mouth ultrasonic debridement (FMUD). Methods: Thirty patients diagnosed with GSCP (≥8 teeth presenting probing depth [PD] ≥5 mm and bleeding on probing [BOP]) were selected and randomly allocated to a control group (n = 15) subjected to FMUD and daily use of a placebo dentifrice or to a test group (n = 15) subjected to FMUD and daily use of a triclosan/copolymer dentifrice. Patients were analyzed for the following parameters: full‐mouth plaque index (FMPI), full‐mouth BOP score (FMBS), gingival recession, PD, and clinical attachment level (CAL). Patients were evaluated at 3 and 6 months by a calibrated and masked examiner. Results: Initially, the groups presented similar periodontal conditions, with no significant differences in any of the parameters evaluated (P >0.05). In both groups, improvements in all periodontal parameters (P <0.05) were seen at the completion of the experimental period. Additionally, the test group showed lower FMPI (3 months) and FMBS (3 and 6 months) than the control group (P <0.05). Moreover, the CAL gain was significantly greater in the test group, especially at initially deep pockets (PD ≤7 mm). Whereas in the control group the CAL gain in deep pockets was 2.7 ± 0.6 mm, in the test group the CAL gain was 3.6 ± 1.4 mm (P <0.05). Conclusion: Within the limits of the present study, the use of triclosan/copolymer dentifrice promoted additional clinical benefits in the treatment of GSCP treated by one‐stage FMUD.