Epidemiology of heart failure in rural Chhattisgarh, India.

Background Cardiovascular diseases, including heart failure (HF), are leading causes of death and disability in India. However, most studies in India only include urban populations or rural regions with improved access and may not represent the poorest patients or regions. We studied the epidemiology of HF patients admitted to a secondary care hospital in rural Chhattisgarh, India.

Lessons learned from academic medical centers' response to the COVID-19 pandemic in partnership with the Navajo Nation.

Introduction: Structural forces that drive health inequalities are magnified in crises. This was especially true during the COVID-19 pandemic, and minority communities were particularly affected. The University of California San Francisco and Health, Equity, Action, Leadership Initiative jointly sent volunteer teams of nurses and doctors to work in the Navajo Nation during the COVID-19 pandemic.

A new mechanism of oxidation in ultrahigh molecular weight polyethylene caused by squalene absorption.

Although synovial fluid lipids were found to absorb in ultrahigh molecular weight polyethylene (UHMWPE) total joint implants in vivo, their effect on the oxidation of the polymer was not known. Current understanding of the oxidation and oxidative stability of UHMWPE joint implants is focused on the presence or elimination of radiation-induced free radicals, which are long-lived and can react with oxygen over the long term. Recently, we found unexplained oxidation in irradiated and melted UHMWPE components that were exposed to bodily fluids then stored on the shelf despite being free of detectable free radicals at the time of implantation.

The elimination of free radicals in irradiated UHMWPEs with and without vitamin E stabilization by annealing under pressure.

Radiation crosslinking of ultrahigh molecular weight polyethylene (UHMWPE) has been used to decrease the wear of joint implant bearing surfaces. While radiation crosslinking has been successful in decreasing femoral head penetration into UHMWPE acetabular liners in vivo, postirradiation thermal treatment of the polymer is required to ensure the oxidative stability of joint implants in the long term. Two types of thermal treatment have been used: (i) annealing below the melting point preserves the mechanical properties but the residual free radicals trapped in the crystalline regions are not completely eliminated, leading to oxidation in the long-term and (ii) annealing above the melting point (melting) eliminates the free radicals but leads to a decrease in mechanical properties through loss of crystallinity during the melting process.

A surface crosslinked UHMWPE stabilized by vitamin E with low wear and high fatigue strength.

Wear particle-induced periprosthetic osteolysis has been a clinical problem driving the development of wear resistant ultrahigh molecular weight polyethylene (UHMWPE) for total joint replacement. Radiation crosslinking has been used to decrease wear through decreased plastic deformation; but crosslinking also reduces mechanical properties including fatigue resistance, a major factor limiting the longevity of joint implants. Reducing UHMWPE wear with minimal detriment to mechanical properties is an unaddressed need for articular bearing surface development.

Transient overexpression of sonic hedgehog alters the architecture and mechanical properties of trabecular bone.

Bone formation and remodeling involve coordinated interactions between osteoblasts and osteoclasts through signaling networks involving a variety of molecular pathways. We hypothesized that overexpression of Sonic hedgehog (Shh), a morphogen with a crucial role in skeletal development, would stimulate osteoblastogenesis and bone formation in adult animals in vivo. Systemic administration of adenovirus expressing the N-terminal form of Shh into adult mice resulted in a primary increase in osteoblasts and their precursors.

Effect of cross-link density on the high pressure crystallization of UHMWPE.

Ultrahigh molecular weight polyethylene (UHMWPE) is a bearing surface material for total joint implants. It is radiation cross-linked for high wear resistance and is melted or treated with vitamin E for oxidative stability. We investigated high pressure crystallization (HPC) of irradiated UHMWPE as an alternative method to improve the mechanical strength while stabilizing the residual free radicals from radiation cross-linking.