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Biomedical subjects

D K Gauthier

Publications and source records attributed to D K Gauthier.

14 recordsLinked to original sources
PubMed2001

Effects of rotational stress of different duration on NK cell activity, proinflammatory cytokines, and POMC-derived peptides in mice.

Previous studies have shown that the same stressor, depending on intensity, controllability, or duration, can have different effects on the immune system. The purpose of this study was to determine the effect of 10- and 20-min rotation on natural killer (NK) cell activity and also to establish if changes in body temperature, proinflammatory cytokine (IL-1beta, IL-6, and TNF-alpha) levels, and proopiomelanocortin (POMC)-derived peptide (ACTH and beta-endorphin) levels parallel the changes in NK cell activity in mice. We found that 10-min rotation significantly increased NK cell activity as compared to both the control (home cage) group and the 20-min-rotation group, while NK cell activity in the 20-min group was not significantly changed compared to the control group. Both 10 and 20 min of rotational stress decreased body temperature and induced significant changes in the proinflammatory cytokine and POMC-derived peptide levels as compared to the control group. The pattern of proinflammatory cytokine expression was quite different between the 10- and 20-min rotation groups. All three proinflammatory cytokines were expressed sequentially (at 0 h after rotation TNF-alpha, at 6 h IL-1beta and IL-6, and at 24 h IL-6) in the 10-min rotation group, while the 20-min rotation group had a small increase in IL-1beta (6.7 +/- 1.8 pg/ml) at 0 h and increased levels of IL-6 at 6 and 24 h. There was a dissociation of ACTH and beta-endorphin expression in both groups resulting in significantly more beta-endorphin (p < 0.05) in the 10-min group at 6 h and significantly more ACTH (p < 0.04) in the 20-min group at 6 h. IL-1beta and beta-endorphin have both been shown to have a direct stimulatory effect on NK cell activity. Therefore, we suspect that the significant increase in both IL-1beta and beta-endorphin at 6 h in the 10-min-rotation group may be involved in the increased NK cell activity observed at 24 h in the 10-min-rotation group.

Adrenocorticotropic Hormone↗
PubMed2000

Immunotherapy of a murine T cell lymphoma localized to the brain.

Mouse YC8 T cell lymphoma was used as a model to determine whether an effective immunotherapy procedure could be devised for the treatment of lymphoma localized to the brain. Implantation of 5 x 10(4) YC8 cells into the left cerebral hemisphere induced rapid loss of the animal's body weight. Severe loss of weight and early deaths were observed in the untreated control group. Although resistance can be conferred to the brain by immunization of naive BALB/c mice, adoptive chemoimmunotherapy procedures were surprisingly not effective in inducing remissions in animals with lymphoma confined to the brain. Even passive transfer of effector cells from immunized, tumor resistant donor animals combined with systemic IL-2 treatment did not impart resistance to recipients with brain tumors. However, regression of the intracranial tumor and apparent cures could be accomplished, when ex vivo cultured effector cells were transferred intravenously.

Adoptive Transfer↗
PubMed2000

Using peer feedback to improve handwashing and glove usage among Thai health care workers.

BACKGROUND: Without protective practices such as Universal Precautions, health care workers are at substantial risk for bloodborne infection, especially in areas such as Thailand with high prevalence of HIV infection. The purpose of this study was to evaluate the effectiveness of a peer feedback program (PFP) on handwashing and glove wearing (HW/GW) among Thai health care workers. METHODS: Subjects (N = 91) were randomly assigned to receive PFP versus no treatment. By using a checklist, peer observers rated HW/GW compliance in their coworkers during patient care. For 1 month, the investigator posted a report of compliance behaviors from each 3 days of observations. HW/GW was also assessed by the investigator by direct observation at 1 month before the intervention, during the intervention period, and 1 month after the intervention. RESULTS: Baseline HW/GW rates for the PFP and control groups were 49.2% and 61.5%, respectively. The PFP group had a significantly higher adjusted compliance rate than the control group during the intervention period (P =.0001). However, there was no significant difference in the compliance scores obtained 1 month after the intervention. CONCLUSIONS: The PFP was effective during the intervention period, but there was no retention of effect. Therefore, adjunct methods should be sought to promote retention of effect.

Adult↗
PubMed1999

Psychoneuroendocrine immunology: perception of stress can alter body temperature and natural killer cell activity.

Psychoimmunology has been credited with using the mind as a way to alter immunity. The problem with this concept is that many of the current psychoimmunology techniques in use are aimed at alleviating stress effects on the immune system rather than at direct augmentation of immunity by the brain. Studies in animals provide a model that permits us to approach the difficulties associated with gaining an understanding of the CNS-immune system connection. A particular advantage of using animals over humans is that psychological and social contributions play a less prominent role for animals than for human subjects, since the animals are all inbred and reared under identical controlled conditions. If the insightful information provided by animal studies is correct, then psychotherapy for the treatment of diseases might be made more effective if some aspect of this knowledge is included in the design of the treatment. We emphasize conditioning as a regimen and an acceptable way to train the brain to remember an output pathway to raise immunity. We propose that a specific drug or perception (mild stress, represented by rotation, total body heating or handling) could substitute and kindle the same output pathway without the need for conditioning. If this view is correct, then instead of using conditioning, it may be possible to use an antigen to activate desired immune cells, and substitute a drug or an external environmental sensory stimulus (perception) to energize the output pathway to these cells. Alternatively, monitoring alterations of body temperature in response to a drug or perception might allow us to follow how effectively the brain is performing in altering immunity. Studies with animals suggest that there are alternative ways to use the mind to raise natural or acquired immunity in man.

Animals↗
PubMed1998

The effect of therapeutic touch on pain and anxiety in burn patients.

The purpose of this single-blinded randomized clinical trial was to determine whether therapeutic touch (TT) versus sham TT could produce greater pain relief as an adjunct to narcotic analgesia, a greater reduction in anxiety, and alterations in plasma T-lymphocyte concentrations among burn patients. Therapeutic touch is an intervention in which human energies are therapeutically manipulated, a practice conceptually supported by Rogers' (1970) theory of unitary human beings. Data were collected at a university burn centre in the south-eastern United States. The subjects were 99 men and women between the ages of 15 and 68 hospitalized for severe burns, and they received either TT or sham TT once a day for 5 days. Baseline data were collected on day 1, data were collected before and after treatment on day 3, and post-intervention data were collected on day 6. Instruments included the McGill Pain Questionnaire, Visual Analogue Scales for Pain, Anxiety and Satisfaction with Therapy, and an Effectiveness of Therapy Form. Blood was drawn on days 1 and 6 for lymphocyte subset analysis. Medication usage for pain in mean morphine equivalents, and mean doses per day of sleep, anxiety and antidepressant medications were recorded. Subjects who received TT reported significantly greater reduction in pain on the McGill Pain Questionnaire Pain Rating Index and Number of Words Chosen and greater reduction in anxiety on the Visual Analogue Scale for Anxiety than did those who received sham TT. Lymphocyte subset analyses on blood from 11 subjects showed a decreasing total CD8 + lymphocyte concentration for the TT group. There was no statistically significant difference between groups on medication usage.

Adolescent↗
PubMed1994

Colonization of mechanical ventilation bags during use.

BACKGROUND: Colonization of patients' mechanical ventilation bags was examined to evaluate two criteria (days in use and appearance) for replacing the disposable adapter that interfaces with the patient. METHODS: Adapters used 1 to 2, 3 to 4 and 6 to 7 days formed groups I, II, and III, respectively (n = 29 to 67 per group). Another group (IA) contained 33 adapters used 1 to 2 days from patients intubated at least 7 days. Appearance of adapters was noted and adapters were swab cultured on nonselective medium. RESULTS: Analysis of variance indicated a difference in log colony-forming units per adapter between groups I and II (p = 0.032), but colony-forming units per adapter varied widely. Group III had a lower mean colony-forming unit count than group II. Groups I and II differed in variables other than days of use, but these confounding variables were eliminated by substituting group IA for group I. When adapter appearance versus colonization was examined by chi 2 test, a significant difference was found between adapters that looked "clean" and those with precipitate or with mucus or blood. CONCLUSIONS: For the subjects studied, colonization of adapters increased significantly between 1 to 2 and 3 to 4 days of use but varied widely. Appearance may be more useful than days in use as a criterion for changing adapters.

Adult↗
PubMed1994

Use of image analysis to measure handwashing effectiveness.

BACKGROUND: This study tested a unique quantification technology (image analysis of fluorescent particles) for the measurement of handwashing effectiveness, comparing an automated system with traditional manual handwashing. In this instance, handwashing "effectiveness" was defined as ability of the technique to remove surface soil, as opposed to removal of microorganisms. METHODS: Sixty-five subjects washed their hands by manual handwashing (day 1) and automated handwashing (day 2). Hands were coated with an oil-based fluorescent suspension, photographed under controlled conditions, washed for 10 seconds, and rephotographed. Photographs from before and after handwashing were subjected to image analysis. RESULTS: Manual handwashing removed 73.1% of the particles; the automated method removed 23.2%. Parameters for use of image analysis as a technique to examine removal of gross contamination from the hands are given in the text. CONCLUSIONS: Although this method will not replace traditional culture methods for examining microbial removal, it is useful for measuring removal of particles (gross contamination) from skin or other surfaces. Under the conditions tested, manual handwashing was found to be decidedly superior to use of an automated system for removal of oil-based soil on the hands.

Automation↗
PubMed1991

Monitoring universal precautions: a new assessment tool.

OBJECTIVES: Two pilot studies were conducted to produce efficacy data on an observational tool designed to assess the use of Universal Precautions (UP) in patient care settings. The instrument addresses barrier precautions, hand-washing, handling of sharps, and avoidance of unprotected mouth to mouth resuscitation. DESIGN: The Universal Precautions Assessment Tool was submitted to a panel of 3 experts to establish consensual validity. It was pilot tested by 2 simultaneous observers to establish interrater reliability. SETTING: Pilot Study I was conducted in 3 different units within a 100-bed U.S. Army hospital. Pilot Study II was conducted in the emergency department of a large university-based hospital. PARTICIPANTS: Subjects observed were registered nurses providing acute patient care. RESULTS: Two simultaneous raters calculated UP compliance rates of 76.4% and 78.6%, respectively, for 9 nurses in Pilot Study I, and 62% and 65%, respectively, for 5 nurses in Pilot Study II. The intraclass correlation coefficient for the raters' scores in Pilot Study I was 0.992 with a 95% confidence interval (0.979, 0.997). Consensual validity was established. CONCLUSIONS: The instrument has acceptable interrater reliability under the conditions used. Limitations to use include the possibility of a Hawthorne effect and the fact that assessing proper implementation of UP occasionally relies on a "judgment call" by the observer. With test conditions adjusted to minimize these limitations and with proper consideration of sample size, the tool can be used by researchers and by monitors of hospital quality control to measure UP compliance of caregivers individually or collectively.

Cooperative Behavior↗
PubMed1990

Trauma: the acute response.

Moderate to severe trauma is followed by a local response, which involves changes in cell function and an inflammatory reaction, and a systemic response coordinated by the nervous and endocrine systems. Early post-trauma alterations in cells are due primarily to decreased oxygen supply and include 1) the shifting of electrolytes and water, either into or out of cells, and 2) the production or release of various local tissue factors. These tissue factors produce changes in blood flow, increased vascular permeability, and other local manifestations of inflammation. Trauma activates nervous and hormonal pathways which help to restore blood volume and maintain the function of essential organs. The effects of these responses on cellular oxygen consumption and body temperature are described. Examples of respiratory system involvement in response to trauma in the lungs or elsewhere are given. These include increased capillary permeability in the lungs, pulmonary emboli, and damage from smoke and heat inhalation.

Emergencies↗
PubMed1989

Anti-HIV antibody testing: procedures and precautions.

Prudent use of screening tests for infection with human immunodeficiency virus (HIV) and interpretation of test results require an understanding of the body's immune response to HIV infection, the serologic assays currently available, and the problems associated with false-positive and false-negative test results. The methodologies of the enzyme immunoassay (enzyme-linked immunosorbent assay [ELISA]) and the Western blot assay are presented, and efficacies of these tests are evaluated. Tests for the detection of anti-HIV antibodies that are, at this time, primarily restricted to research use but that show promise for adaptation to screening (such as the ELISA with recombinant antigen) also are discussed, as is the alternative of testing for HIV antigens or HIV-specific DNA. From a personal perspective, any test for HIV infection is accompanied by certain benefits and risks. These can be discussed with the patient in the framework of pretest and posttest counseling.

AIDS Serodiagnosis↗
PubMed1970

Nitrate reductase and soluble cytochrome c in Spirillum itersonii.

The addition of nitrate to cultures of Spirillum itersonii incubated under low aeration produced a diauxic growth pattern in which the second exponential phase was preceded by the appearance of nitrite in the medium. The organism also grew anaerobically in the presence of nitrate. Nitrate reductase activity could be demonstrated in cell-free extracts by use of reduced methyl viologen as the electron donor. The enzyme was located in the supernatant fraction after centrifugation of extracts for 2 hr at 40,000 x g, and it sedimented as a single peak when centrifuged in a sucrose gradient. Nitrate reductase activity was found in cells grown with low aeration without nitrate, but was increased about twofold by addition of nitrate. Enzyme activity was negligible in cells grown with high aeration. The proportion of soluble cytochrome c was increased two- to threefold in cells grown with nitrate. The specific activities of nitrate reductase and soluble cytochrome c rose when nitrate or nitrite was added to cell suspensions incubated with low aeration; nitrite was more effective than nitrate during the early stages of incubation. A nitrate reductase-negative mutant synthesized increased amounts of soluble cytochrome c in response to nitrate or to nitrite in the cell suspension system. It is concluded that enhanced synthesis of soluble cytochrome c does not require the presence of a functional nitrate reductase.

Cell-Free System↗