Nucleotide metabolic mismatches in mammalian hearts: implications for transplantation

Introduction

Human donor organ shortages have led surgeons and scientists to explore the use of animals as alternative organ sources. Acute thrombovascular rejection (AVR) is the main hurdle in xenotransplantation. Disparities in nucleotide metabolism in the vessels of different species may contribute significantly to the microvascular component of AVR.

Methods

We evaluated the extent of nucleotide metabolism mismatch in selected organs and endothelial cells of different mammals with particular focus on the changes in activity of ecto-5’-nucleotidase (E5’N) elicited by exposure of porcine hearts or endothelial cells to human blood (ex vivo) or human plasma (in vitro).

Results

E5’N activity in the rat heart was significantly higher than in other species. We noted a significant difference (p<0.001) in E5’N activity between human and pig endothelial cell lines. Initial pig aortic endothelial E5’N activity decreased in vitro after a three-hour exposure to human and porcine plasma while remaining constant in controls. Ex vivo perfusion with fresh human blood for four hours resulted in a significant decrease of E5’N activity in both wild type and transgenic pig hearts overexpressing human decay accelerating factor (p<0.001).

Conclusions

This study provides evidence that mismatches in basal mammalian metabolic pathways and humoral immunity interact in a xenogeneic environment. Understanding the role of nucleotide metabolism and signalling in xenotransplantation may identify new targets for genetic modifications and may lead to the development of new therapies extending graft survival.     

Ultrasound as visual feedback in speech habilitation: Exploring consultative use in rural British Columbia,Canada

Ultrasound has shown promise as a visual feedback tool in speech therapy. Rural clients, however, often have minimal access to new technologies. The purpose of the current study was to evaluate consultative treatment using ultrasound in rural communities. Two speech‐language pathologists (SLPs) trained in ultrasound use provided consultation with ultrasound in rural British Columbia to 13 school‐aged children with residual speech impairments. Local SLPs provided treatment without ultrasound before and after the consultation. Speech samples were transcribed phonetically by independent trained listeners. Eleven children showed greater gains in production of the principal target // after the ultrasound consultation. Four of the seven participants who received more consultation time with ultrasound showed greatest improvement. Individual client factors also affected outcomes. The current study was a quasi‐experimental clinic‐based study. Larger, controlled experimental studies are needed to provide ultimate evaluation of the consultative use of ultrasound in speech therapy.     

The Healthy Brains and Behavior Study: objectives,design, recruitment,and population coverage

Violence is increasingly viewed as a public health issue that may be ameliorated by health‐based interventions. The Healthy Brains and Behavior Study (HBBS) aims to identify environmental and biological risk factors for aggression in late childhood and to reduce aggression through psychological and nutritional treatments. Utilizing a cross‐disciplinary collaborative research approach, the HBBS has both human and animal components. The human component has two stages consisting of risk assessment followed by treatment. The risk assessment is based on 451 community‐residing children aged 11–12 years and their caregivers, during which genetic, brain imaging, neuroendocrine, psychophysiology, environment toxicology, neurocognitive, nutrition, psychological, social and demographic risk variables are collected. Children who met criteria (N = 219) for problematic aggressive behaviors were assigned to one of four treatment groups: cognitive‐behavior therapy (CBT) alone, nutritional supplements alone, both CBT and nutrition, or treatment‐as‐usual. Treatment duration was 12 weeks and all children whether in treatment or not were followed‐up at three, six, and 12 months. The animal component assessed the effects of dietary omega‐3 fatty acids on the development of aggression. This study contributes knowledge on how biological factors interact with social factors in shaping proactive and reactive aggression and assesses the efficacy of treatment approaches to reduce childhood aggression. Copyright © 2013 John Wiley & Sons, Ltd.     

Effects of social and spatial contexts on young latinas’ methamphetamine use initiation

ABSTRACT

In this article, we examine methamphetamine (meth) use initiation as influenced by Latinas’ social positions within institutions (e.g., family and economy). We conducted ethnographic fieldwork in five women’s residential substance use treatment facilities in Los Angeles County with women who considered meth to be their primary drug of choice. Using an urban ethnographic framing, we demonstrate the effects of low-income young Latinas’ spatial- and social-context rendered vulnerability to abuse and neglect, and the resulting emotional distress, on meth use initiation. When considering pathways to substance use intervention for vulnerable Latina girls and women, clinicians, researchers, and policy makers need to understand substance use pathways as dynamic processes to cope with psychosocial stress while living in communities with easy access to illicit substances such as methamphetamine.     

Gradient of microglial activation in the brain of SIV infected macaques

Brains of macaques inoculated with macrophage-tropic, neurovirulent virus 7F, with lymphocyte-tropic SIV mac239, or with dual-tropic SIVmac239/1yE, were examined for microglial activation, astrocyte activation, apoptosis and neuron loss. The brain one animal inoculated with neurovirulent virus 7f showed massive microglial activation as assessed by expression of the major histo-compatibility complex class II (MHC-II). In this animal very numerous, large microglial nodules expressing MHC-II were concentrated in the basal pons and internal capsule. These microglial nodules contained cells undergoing apoptosis detected by in situ end labeling of fragmented DNA. In this animal, neuron loss was apparent near the microglial nodules. In the animals inoculated with SIVmac239 or SIVmac239/17E, pathologic changes such as perivascular cuffing and formation of microglial nodules were absent. However, increased expression of MHC-11 by microglial cells was also concentrated in white matter of the basal pons, midbrain and internal capsule. These results indicate the microglial activation in SIV-infected macaques follows a ventral to dorsal gradient regardless of viral tropism. These results also show that the type and severity of neuropathological changes in SIV-infected macaques is highly dependent on the tropism of the inoculated virus.     

Myosin-V stepping kinetics: a molecular model for processivity

Myosin-V is a molecular motor that moves processively along its actin track. We have used a feedback-enhanced optical trap to examine the stepping kinetics of this movement. By analyzing the distribution of time periods separating discrete approximately 36-nm mechanical steps, we characterize the number and duration of rate-limiting biochemical transitions preceding each such step. These data show that myosin-V is a tightly coupled motor whose cycle time is limited by ADP release. On the basis of these results, we propose a model for myosin-V processivity.     

Biliary giardiasis in a patient with human immunodeficiency virus

A 41-year-old man with human immunodeficiency virus (HIV) (CD4 count, 446/mm3) developed a protracted course of abdominal pain, weight loss, and increasing liver function tests after undergoing a metronidazole treatment regimen for Giardia enteritis. Three months later, endoscopic retrograde cholangiography (ERCP) showed dilated common and intrahepatic bile ducts and luminal irregularities of the common bile duct. Seven months after the onset of his acute diarrhea, a repeat ERCP with aspiration demonstrated many Giardia trophozoites and cysts in the bile and continued structural abnormalities consistent with cholangiopathy. A 10-day course of high-dose intravenous metronidazole did not resolve these signs or symptoms. A gallbladder ultrasound showed a thickened wall. Laparoscopic cholecystectomy led to resolution of abdominal pain and normalization of serum alkaline phosphatase over an 8-month period. Gallbladder histopathology revealed chronic cholecystitis, but no parasites were seen on hematoxylin and eosin staining or with Giardia antigen enzyme immunoassay testing of the gallbladder. The patient refused to undergo a follow-up ERCP, but a right upper quadrant ultrasound and computed tomography of the abdomen were normal.     

Application of a Best Practice Approach Using Resonant Mass Measurement for Biotherapeutic Product Characterization

Characterizing and quantifying subvisible particles in protein drug products is critical to ensuring product quality. A variety of analytical methods are used to detect and make meaningful measurements of subvisible particles. Resonant mass measurement (RMM) is a novel technology that characterizes the subvisible particle content of samples on a particle-by-particle basis. The technology presents great promise in the study of therapeutic protein products. As an emerging tool in the biopharmaceutical field, the best practices and limitations of RMM for protein products have not been well established. One key challenge of particle analysis is producing robust and reliable data, with high precision and accuracy, for particle characterization. In this study, we develop a set of possible best practices for RMM using a model protein system. We test the effects of these practices on the repeatability and reproducibility of particle measurements. Additionally, we present the data collected under a rigorously controlled set of operating conditions at 3 collaborating sites as well as a summary of the resulting optimal practices. In employing these practices, we successfully obtained improved relative standard deviation values and achieved high reproducibility and repeatability in both sizing and concentration measurement results over a broad range of sample volumes.