Biomedical subjects

Mary T Johnson

Publications and source records attributed to Mary T Johnson.

12 recordsLinked to original sources

PubMed2006

Characterization of pulsed magnetic field therapy in a rat model for rheumatoid arthritis.

Recent studies have shown that pulsed magnetic fields (PMF) provide a practical, exogenous method for inducing cell and tissue modifications, as therapy for selected pathological states. A number of clinical studies, in vivo animal experiments and in vitro cellular and membrane research reports suggest that PMF stimulation can significantly reduce pain and accelerate the healing process. However, PMFs are still not widely used in clinical medicine. This research examines the effects of PMFs using an animal model that resembles human rheumatoid arthritis. Using serum protein electrophoresis (SPE) and joint edema evaluation, we were able to monitor disease progression and PMF therapeutic effectiveness. We have used these methods to correlate changes in an acute phase serum protein, alpha-2-macroglobulin, with other indicators of rheumatoid arthritis in Lewis rats treated daily with PMF therapy. The results indicate that PMFs may be a promising non-invasive treatment for chronic inflammatory diseases like rheumatoid arthritis.

Animals↗

PubMed2006

Localized pulsed magnetic fields for tendonitis therapy.

Energy medicine has existed for centuries in some parts of the world, but in recent years, western health care practitioners have taken a heightened interest in these therapies. Treatment by use of pulsed magnetic fields (PMF) is currently being explored in both chronic and inflammatory diseases such as cancer, epilepsy, psoriasis, rheumatoid arthritis, and tendinitis. In the U.S., PMFs have already been approved for use in treatment of bone fractures in humans and clinical trials have been conducted for lower back pain. This study presents a summary of the therapeutic potential of a localized PMF treatment for tendinitis using the Softpulse III system. This system has been used to accelerate wound healing and soft tissue swelling. It generates a specific PMF that induces an electrical field within the tendon. This induced electrical field is thought to influence the healing process by affecting the inflammatory cells that line the tendon sheath. In this study, we have used an established model of tendinitis along with a validated method for appraising edema and gait (Achilles' Functional Index), to test the hypothesis that the proposed PMF signal is effective in reducing the indicators of acute tendinitis injury. These experiments were approved by the Institutional Animal Care and Use Committee. Our findings suggest a role for the treatment of soft tissue injury using the Softpulse III therapeutic device. The symbolic stand point of PMF treatments is to push the need for a revolutionary leap, from the more dominant pharmaceutical and surgical interventions, to the advanced applications of non-invasive therapies that would minimize the medicinal risk of side effects, and eliminate the risk of complicated drug interactions.

Animals↗

PubMed2004

Th2 cytokines IL-4 and IL-13 downregulate paxillin expression in bronchial airway epithelial cells.

Asthma is characterized by infiltration and shedding of the bronchial epithelium. The Th2 cytokines IL-4 and IL-13 are involved in the cellular recruitment and infiltration seen in asthma. The effects of IL-4 and IL-13 on cell-matrix interactions and epithelial shedding are unknown. We hypothesize that bronchial airway epithelial cells (BAEC) express paxillin, a structural focal adhesion protein, and downregulation of paxillin by Th2 cytokines lead to BAEC hyperpermeability. We showed by confocal microscopy the presence of paxillin in BAEC. We demonstrated by Western blot analysis that IL-4 and IL-13 stimulation results in downregulation of paxillin production. IL-4 and IL-13 stimulation decreased epithelial cell-matrix attachment as measured by electrical cell-substrate impedance sensing system (ECIS). Our results suggest that Th2 cytokines IL-4 and IL-13 downregulate paxillin production by BAEC, thereby disrupting the cell-matrix interactions. This may help explain the epithelial shedding and epithelial membrane hyperpermeability that occurs in asthma.

Bronchi↗

PubMed2004

Effects of cold stress on spleen cell proliferation and cytokine production during chronic Toxoplasma gondii infection.

BACKGROUND: Cell-mediated immunity is critical for controlling infection and preventing reactivation during the chronic phase of Toxoplasma gondii infection. In people suffering from AIDS, T. gondii is one of the major opportunistic infectious agents. Mechanisms regulating rapid development of clinical signs in previously asymptomatic patients remain unclear; however, cofactors such as stress are suspected to play a role in the susceptibility to opportunistic infections. OBJECTIVE: This study examined the role of cold stress (CS) in splenocyte function during chronic T. gondii infection. METHODS: Control mice and mice previously infected orally with T. gondii were subjected to CS during the chronic phase (CSchr), i.e. 90 days after infection, and in vitro cell proliferation and cytokine production were measured before (day 0) and 1, 15 and 25 days after CSchr. Splenocyte proliferation and cytokine production were measured after in vitro stimulation with concanavalin A (Con-A), anti-CD3 antibody (A-CD3) and Toxoplasma lysate antigen. RESULTS: CSchr enhanced splenocyte proliferation in cells stimulated with Con-A and A-CD3, but it suppressed proliferation in cells stimulated with T. gondii antigens. Increased levels of interferon (IFN)-gamma were detected independent of the type of stimulation after CSchr and remained high throughout the experiment. CS had similar results in noninfected animals. CONCLUSION: Although an overall increase in splenocyte function occurred after nonspecific stimulation, CS suppressed primed spleen cells from responding to T. gondii antigens which could lead to reactivation of latent infection. The increase in IFN-gamma after CSchr could be a result of spleen cells being primed by released parasites by this stressor. IFN-gamma is critical in the control of parasite reactivation.

AIDS-Related Opportunistic Infections↗

PubMed2004

Effect of hydrogen peroxide on proliferation, apoptosis and interleukin-2 production of Jurkat T cells.

Hydrogen peroxide (H2O2) is well known as a cell damaging agent that is produced during normal cell metabolism of aerobic organisms. An excessive production of oxygen metabolites such as H2O2 leads to oxidative stress and disease. On the other hand, it recently was discovered that H2O2 is not only a deleterious oxidant for cells but can also play an important role as a beneficial signaling molecule in certain cells such as T lymphocytes. T lymphocytes are major regulatory cells in the inflammatory cascade and can act by releasing either toxins or beneficial signaling molecules. Understanding how to regulate the actions of H2O2 in T cells will allow for the creation of novel ways to improve the treatment of inflammatory diseases. The current study presents baseline information on the effects of H2O2 on Jurkat cells, a T cell line that we use as a T cell model for therapeutic research. We first determined the half-life of 0-80 mumolar H2O2 added to Jurkat cultures using a realtime H2O2 monitoring system. We then exposed Jurkat cells to such H2O2 concentrations and found that 50 +/- 10 mumolar H2O2 promoted interleukin-2 production in cells activated with anti-CD3 at the T cell receptor plus phorbol myristate acetate as a co-stimulatory signal. These effects were not seen in non-activated, normal Jurkat cells, where H2O2 inhibited cell proliferation and induced apoptosis in a dose-dependent way without affecting interleukin-2 production. Our data indicate that Jurkat cells can model both healthy and inflammatory T cells that respond differently to oxidative metabolites such as H2O2.

Apoptosis↗

PubMed2004

Noninvasive treatment of inflammation using electromagnetic fields: current and emerging therapeutic potential.

Magnets, electric current and time varying magnetic fields always have played a role in human medicine. Natural magnetic stones were used in ancient cultures to induce a therapeutic effect and modern clinical practice would be far less effective without nuclear magnetic resonance imaging, cardiac pacemakers, and bone growth stimulators. This paper presents a summary of natural and artificial electromagnetic field (EMF) characteristics that are currently in use or under investigation for other therapeutic applications. This background understanding provides a basis for discussion on the success and possible risks of emerging and novel EMF therapies. Although interest in energy medicine has existed for centuries in some parts of the world, in recent years this is an area of heightened interest for western healthcare practitioners. This awareness has been triggered by the growing body of knowledge on how EMFs interact with cellular systems. EMF therapy for the treatment of pain, cancer, epilepsy, and inflammatory diseases like psoriasis, tendinitis and rheumatoid arthritis is currently being explored. The long-term success of this new area of medicine is still unknown. On the one hand, it remains to be seen whether positive human outcomes with EMF therapy could be explained by enhancement of the placebo effect. Optimistically, EMF therapy has the potential to revolutionize medicine, which is currently dominated by pharmaceutical and surgical interventions. In this case, new therapeutic tools may be developed for future clinicians to provide noninvasive treatments with low risk of side effects and no problem with drug interactions.

Animals↗

PubMed2003

Autoradiographic evaluation of electromagnetic field effects on serotonin (5HT1A) receptors in rat brain.

Serotonin (5HT1A) is a chemical mediator of inflammation and the largest single neurotransmitter system of the brain. Its secretion and physiological actions mediate stress and pain, affecting both immune and nervous system functions through the hypothalamic-pituitary-adrenal axis. Serotonin receptor dysfunction is well-characterized in mental disturbances like depression and anxiety. Transcranial magnetic stimulation has been used therapeutically to treat refractory disorders like non-responsive depression and may act in part through its effect on 5HT1A receptors. Previously we have shown that in vitro, 5HT1A receptor binding to a radioactive agonist can be modulated by specific intensity and frequency electromagnetic fields (EMFs). In the present report we have used quantitative receptor autoradiography to evaluate 5HT1A receptor density in rat brain and the impact of pulsed EMF exposure on receptor binding in key brain regions. Rats used in this study had whole body exposures to either a geofield control or to pulsed EMFs to evaluate the treatment for chemically-induced tendinitis. Since the brains were exposed coincidentally as a consequence of the main experiment, we investigated the potential for EMF-induced changes in areas such as the hippocampus. This pilot study should provide a detailed understanding of magnetic field effects on stress-responsive brain regions and will lead to a more coordinated approach to the use of such modalities for therapeutic intervention in humans.

Animals↗

PubMed2003

Use of proteomics methodology to evaluate inflammatory protein expression in tendinitis.

In previous studies we established a rat model of acute tendinitis including functional and mechanical measures of healing. Achilles' tendinitis was induced by injection of collagenase, an enzyme that produces localized fiber digestion and edema formation. As quantitative measures of tissue inflammation, hypercellularity and edema were evaluated in injured tendons in comparison with controls. Using the rat tendinitis model, we have applied isotope-coded affinity tag analysis (ICAT) methodology to indicate localized tendon healing by quantitating protein expression. This novel proteomics method allows detection of subtle differences in protein levels that provide a detailed picture of tendinitis healing. The method involves a new class of chemical linkers used to differentially label cysteine residues from similar peptides in control and treated protein samples with heavy (deuterium off of backbone) and light (hydrogen off of backbone) ICAT reagents that are otherwise chemically identical. Proteins were extracted under liquid nitrogen from control untreated or injured Achilles' tendons 72 hours after collagenase-injection. These proteins were digested with endoproteinase Glu-C and trypsin and the resulting peptide mixtures were evaluated using reverse-phase C18 HPLC and Tristricine SDS-polyacrylamide gel electrophoresis. The two ICAT-modified peptide populations were mixed, affinity-purified and analyzed using microcapillary liquid chromatography and electrospray ionization tandem mass-spectroscopy. The process resulted in relative abundance and charge-to-mass ratio data used in conjunction with database searching to identify proteins expressed differentially in the two treatment groups. By analyzing different time periods in the healing process, an accurate model of the healing rat tendon can be made.

Achilles Tendon↗

PubMed2003

Characterization of a real time H2O2 monitor for use in studies on H2O2 production by antibodies and cells.

It was recently shown that antibodies catalyze a reaction between water and ultraviolet light (UV) creating singlet oxygen and ultimately H2O2. Although the in vivo relevance of these antibody reactions is unclear, it is interesting that among a wide variety of non-antibody proteins tested, the T cell receptor is the only protein with similar capabilities. In clinical settings UV is believed to exert therapeutic effects by eliminating inflammatory epidermal T cells and we hypothesized that UV-triggered H2O2 production is involved in this process. To test the hypothesis we developed tools to study production of H2O2 by T cell receptors with the long-term goal of understanding, and improving, UV phototherapy. Here, we report the development of an inexpensive, real time H2O2 monitoring system having broad applicability. The detector is a Clark oxygen electrode (Pt, Ag/AgCl) modified to detect UV-driven H2O2 production. Modifications include painting the electrode black to minimize UV effects on the Ag/AgCl electrode and the use of hydrophilic, large pore Gelnots electrode membranes. Electrode current was converted to voltage and then amplified and recorded using a digital multimeter coupled to a PC. A reaction vessel with a quartz window was developed to maintain constant temperature while permitting UV irradiation of the samples. The sensitivity and specificity of the system and its use in cell-free and cell-based assays will be presented. In a cellfree system, production of H2O2 by CD3 antibodies was confirmed using our real time H2O2 monitoring method. Additionally we report the finding that splenocytes and Jurkat T cells also produce H2O2 when exposed to UV light.

Animals↗

PubMed2002

Effect of short duration electromagnetic field exposures on rat mass.

Daily preexposure and postexposure mass measurements of 65 rats (young males and females, old males) a proprietary pulsed wound healing field, pulsed electromagnetic field, (PEMF), or their control fields for 4 h/day for 21 days. Statistical analysis of mass changes over time showed that young rats exposed to PEMF lost more mass and recovered it more slowly compared to controls (2-4% more loss) than did older PEMF exposed rats or any 60 Hz exposed rats. We conclude that daily preexposure and postexposure mass measurements are needed to adequately assess the effects of electromagnetic fields on body mass.

Achilles Tendon↗

PubMed2002

Quantitative characterization of rat tendinitis to evaluate the efficacy of therapeutic interventions.

Tendinitis is a painful soft tissue pathology that accounts for almost half of all occupational injuries in the United States. It is often caused by repeated movements and may result in loss of work and income. Current treatments for tendinitis are aimed at reducing inflammation, the major cause of the pain. Although anti-inflammatory drugs and various alternative therapies are capable of improving tendinitis, there are no quantitative scientific data available regarding their impact on inflammation. The objective of this study is to determine the time course for healing of rat tendinitis without intervention to be able to assess the efficacy of tendinitis treatments. We are interested in evaluating the therapeutic use of pulsed electromagnetic fields (PEMFs), a therapeutic modality that has been found to be beneficial for healing soft tissue injuries. Tendinitis was induced in Harlan Sprague Dawley rats by collagenase injections into the Achilles tendon, and tendons were collected for four weeks post-injury. To determine the amount of edema, we used caliper measurements of the rat ankles and quantified the tendon water content. To determine the extent of inflammation, we estimated the number of inflammatory cells on histological sections applying stereological methods. The data reveal that edema is maximal 24 hours after injury accompanied by a massive infiltration of inflammatory cells. Inflammatory cells are then gradually replaced by fibroblasts, which are responsible for correcting damage to the extracellular matrix. This natural time course of tendon healing will be used to evaluate the use of PEMFs as a possible therapeutic modality.

Animals↗

PubMed2002

The Bactericidal And Cytotoxic Effects Of Antimicrobial Wound Cleansers.

OBJECTIVE: Wound care is a part of daily activity for many athletic trainers. Knowing which cleansers are effective against the bacteria that most commonly cause infection and whether they are toxic to healthy cells enables athletic trainers to make educated decisions on which cleanser to use. We compared the bactericidal effectiveness and cytotoxicity to human fibroblast cells of 4 cleansers at various dilutions. DESIGN AND SETTING: A 4 x 4 factorial design was used for the cytotoxicity testing. The independent variables were type and dilution of cleanser. The dependent variable was cell viability of the human fibroblast cells. We used a 2 x 3 x 4 x 4 factorial design for the bacterial testing. The independent variables were type and dilution of bacteria and type and dilution of cleanser. The dependent variable was the bactericidal action of the cleanser on the bacteria. SUBJECTS: Human foreskin samples were used to obtain a line of fibroblast cells. Bacterial samples were obtained from an athletic training clinic, isolated from swabs of a whirlpool water supply valve (Pseudomonas aeruginosa) or skin surface (Staphylococcus aureus). MEASUREMENTS: We obtained bactericidal measurements by testing isolated Gram-negative (Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria. Minimum and maximum concentrations were identified according to bactericidal effectiveness. Cytotoxicity measurements were obtained from spectrophotometer readings of a neutral red assay for fibroblast cell viability. Final dilutions tested were determined by pilot testing. RESULTS: At the 1:5 dilution of product in sterile 0.9% saline, both Cinder Suds and Nitrotan and hydrogen peroxide were different from the control with regard to Pseudomonas aeruginosa. At the 1:10 dilution, both Betadine and hydrogen peroxide were different from the control with regard to Pseudomonas aeruginosa. These 2 cleansers were also different from each other. At the 1:10 dilution, only Betadine was not different from the control for the cytotoxicity testing. CONCLUSIONS: Betadine was both effective against bacteria and not harmful to human fibroblast cells at a 1:10 dilution of a commercially purchased solution.

Journal Article↗