Biomedical subjects

James P Chambers

Publications and source records attributed to James P Chambers.

7 recordsLinked to original sources

PubMed2005

Amplification of Herpes simplex type 1 and Human Herpes type 5 viral DNA from formalin-fixed Alzheimer brain tissue.

It is known that nucleic acids from formalin-fixed tissues are not nearly as good templates for DNA amplification as those extracted from fresh tissues. However, specimens stored in most pathologic archives are initially fixed in formalin. The possibility of an infectious etiology of several diseases including Alzheimer's underscores the usefulness of archived tissue in assessing the association of infectious agents with specific pathology. In this report, we describe in detail a method resulting in robust amplification of HSV1 and Human Herpes type (HHV) 5 viral DNA targets using formalin-fixed Alzheimer brain frontal and temporal tissue as source of amplification template. Herpes simplex type 2 viral DNA was not detected in the limited samples examined in this study. Amplicons were verified by sequence analysis. Brain tissue stored in formalin longer than 1 year prior to post-formalin-fixation analysis gave rise to significantly shorter amplicons consistent with the observation that template DNA integrity decreases significantly with increasing time of storage in formalin. Thus, this report should be useful in PCR-based investigations assessing the regional presence of viral DNAs in formalin-fixed brain tissue.

Alzheimer Disease↗

PubMed2005

A microfluidic SELEX prototype.

Aptamers are nucleic acid binding species capable of recognizing a wide variety of targets ranging from small organic molecules to supramolecular structures, including organisms. They are isolated from combinatorial libraries of synthetic nucleic acid by an iterative process referred to as SELEX (Systematic Evolution of Ligands by Exponential Enrichment). Here we describe an automated microfluidic, microline-based assembly that uses LabView-controlled actuatable valves and a PCR machine, and which is capable of the selection and synthesis of an anti-lysozyme aptamer as verified by sequence analysis. The microfluidic prototype described is 1) a simple apparatus that is relatively inexpensive to assemble, making automated aptamer selection accessible to many investigators, and 2) useful for the continued "morphing" of macro-->meso-->microfabricated structures until a convergence to a few functional systems evolves and emerges, partly or completely achieving simpler, smaller and more rapid SELEX applications.

Electrophoresis, Agar Gel↗

PubMed2005

Exogenous administration of Substance P enhances wound healing in a novel skin-injury model.

Soft tissue injury accounts for approximately 44% of all wounds in both the military and civilian populations. Following injury to soft tissue, Substance P (SP) and other neuropeptides are released by cutaneous neurons and modulate the function of immunocompetent and inflammatory cells, as well as epithelial and endothelial cells. The interaction between these components of the nervous system and multiple target cells affecting cutaneous repair is of increasing interest. In this report, we describe the effects of SP on wound repair in a novel, laser-induced, skin-wound model. Gross and histologic examination of laser-induced injury revealed that exogenously administered SP affects wound healing via neurite outgrowth, in addition to adhesion molecule and neurokinin-1 receptor involvement in vivo. All SP effects were decreased by pretreatment with Spantide II, an SP antagonist. The elucidation of SP-mediating mechanisms is crucial to firmly establishing the involvement and interaction of the peripheral nervous system and the immune system in cutaneous repair. Findings presented here suggest that SP participates in the complex network of mediators involved in cutaneous inflammation and wound healing.

Animals↗

PubMed2005

Influenza A (H3N2) outbreak, Nepal.

In July 2004, an outbreak of influenza A (H3N2) was detected at 3 Bhutanese refugee camps in southeastern Nepal. Hemagglutination inhibition showed that approximately 40% of the viruses from this outbreak were antigenically distinct from the A/Wyoming/3/03 vaccine strain. Four amino acid differences were observed in most of the 26 isolates compared with the A/Wyoming/3/2003 vaccine strain. All 4 substitutions are located within or adjacent to known antibody-binding sites. Several isolates showed a lysine-to-asparagine substitution at position 145 (K145N) in the hemagglutinin molecule, which may be noteworthy since position 145 is located within a glycosylation site and adjacent to an antibody-binding site. H3N2 viruses continue to drift from the vaccine strain and may remain as the dominant strains during the 2005-2006 influenza season. Thus, the 2005-2006 Northern Hemisphere vaccine strain was changed to A/California/7/2004, a virus with all 4 amino acid substitutions observed in these Nepalese isolates.

Amino Acid Sequence↗

PubMed2004

Comparison of TaqMan and Epoch Dark Quenchers during real-time reverse transcription PCR.

Several biotechnology companies have recently introduced novel quencher fluors for use with dual-labeled fluorogenic hydrolysis probes. The Epoch Dark Quencher trade mark fluorochrome consists of a non-fluorescent moiety capable of absorption at higher wavelengths (400-650 nm). The aim of this study was to: (1) evaluate the feasibility of using Epoch Dark Quencher fluorochromes in real-time PCR pathogen detection assays that were previously optimized with TaqMan (TAMRA) quenching fluors, and (2) compare the sensitivity based on cycle threshold (CT) between probes containing either TaqMan or Epoch Dark Quencher fluors. Our data indicate Epoch Dark Quencher probes can be used in place of TaqMan probes and their performance was not better than traditional TaqMan (TAMRA) quenchers. Marginal differences observed between quenching fluorochromes may arise from concentration differences during probe synthesis.

Fluorescent Dyes↗

PubMed2003

Production of tumor necrosis factor-alpha, interleukin 1-beta, interleukin 2, and interleukin 6 by rat leukocyte subpopulations after exposure to substance P.

The interaction between components of the nervous system and multiple target cells in the cutaneous immune system has been receiving increasing attention. Recently, the involvement of neuropeptides has been demonstrated to play an important role in the inflammatory cascade. Neuropeptides such as Substance P are released by cutaneous neurons and modulate the function of immunocompetent and inflammatory cells as well as epithelial and endothelial cells. Substance P has been shown to function as a mediator for cell proliferation, cytokine production, and as an upregulator of various cell surface receptors. In this study, we show the effect of Substance P on the production of Tumor Necrosis Factor-alpha, Interleukin 1-beta, Interleukin 2, and Interleukin 6 by T-lymphocytes, macrophages and neutrophils. These data demonstrate that pathophysiological levels of Substance P induce production of cytokines in all three cell populations tested. Interestingly, T-cells demonstrated the highest percentage of cells expressing all four cytokines. In contrast, macrophages and neutrophils produced the highest absolute levels of cytokines. The elucidation of mediating mechanisms of Substance P activation of leukocytes is crucial to the understanding of the cutaneous inflammatory cascade and involvement of the peripheral nervous system on the immune system. These findings suggest that Substance P participates in the complex network of mediators that regulate cutaneous inflammation and potentially the rate of wound healing.

Animals↗

PubMed2002

Modification of sonic boom wave forms during propagation from the source to the ground.

A number of physical processes work to modify the shape of sonic boom wave forms as the wave form propagates from the aircraft to a receiver on the ground. These include frequency-dependent absorption, nonlinear steepening, and scattering by atmospheric turbulence. In the past two decades, each of these effects has been introduced into numerical prediction algorithms and results compared to experimental measurements. There is still some disagreement between measurements and prediction, but those differences are now in the range of tens of percent. The processes seem to be understood. The present understanding of sonic boom evolution will be presented along with experimental justification.

Aircraft↗