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Biomedical subjects

M F Davis

Publications and source records attributed to M F Davis.

18 recordsLinked to original sources
PubMed2003

Toxoplasma gondii isolates from free-ranging chickens from the United States.

Prevalence of Toxoplasma gondii infection in chickens is a good indicator of the strains prevalent in their environment because they feed from ground. The prevalence of T. gondii was determined in 118 free-range chickens from 14 counties in Ohio and in 11 chickens from a pig farm in Massachusetts. Toxoplasma gondii antibodies (> or = 1: 5) were found using the modified agglutination test (MAT) in 20 of 118 chickens from Ohio. Viable T. gondii was recovered from 11 of 20 seropositive chickens by bioassay of their hearts and brains into mice. The parasite was not isolated from tissues of 63 seronegative (< or = 1:5) chickens by bioassay in cats. Hearts, brains, and muscles from legs and breast of the 11 chickens from the pig farm in Massachusetts were fed each to a T. gondii-negative cat. Eight cats fed chicken tissues shed oocysts; the 3 cats that did not shed oocysts were fed tissues of chickens with MAT titers of 1:5 or less. Tachyzoites of 19 isolates of T. gondii from Ohio and Massachusetts were considered avirulent for mice. Of 19 isolates genotyped, 5 isolates were type II and 14 were type III; mixed types and type I isolates were not found.

Agglutination Tests↗
PubMed2002

Use of pyrolysis molecular beam mass spectrometry (py-MBMS) to characterize forest soil carbon: method and preliminary results.

The components of soil organic matter (SOM) and their degradation dynamics in forest soils are difficult to study and thus poorly understood, due to time-consuming sample collection, preparation, and difficulty of analyzing and identifying major components. As a result, changes in soil organic matter chemical composition as a function of age, forest type, or disturbance have not been examined. We applied pyrolysis molecular beam mass spectrometry (py-MBMS), which provides rapid characterization of SOM of whole soil samples. to the Tionesta soil samples described by Hoover, C.M., Magrini, K.A., Evans, R.J., 2002. Soil carbon content and character in an old growth forest in northwestern Pennsylvania: a case study introducing molecular beam mass spectrometry (PY-MBMS). Environmental Pollution 116 (Supp. 1), S269-S278. Our goals in this work were to: (1) develop and demonstrate an advanced, rapid analytical method for characterizing SOM components in whole soils, and (2) provide data-based models to predict soil carbon content and residence time from py-MBMS analysis. Using py-MBMS and pattern recognition techniques we were able to statistically distinguish among four Tionesta sites and show an increase in pyrolysis products of more highly decomposed plant materials at increasing sample depth. For example, all four sites showed increasing amounts of older carbon (phenolic and aromatic species) at deeper depths and higher amounts of more recent carbon (carbohydrates and lignin products) at shallower depths. These results indicate that this type of analysis could be used to rapidly characterize SOM for the purpose of developing a model, which could be used in monitoring the effect of forest management practices on carbon uptake and storage.

Carbon↗
PubMed2001

ER and PR in renomedullary interstitial cells during Syrian hamster estrogen-induced tumorigenesis: evidence for receptor-mediated oncogenesis.

The estrogen-induced and -dependent Syrian hamster renal tumor is the most intensively studied model in estrogen carcinogenesis. Yet, it remains confounding that the kidney of this species behaves as an estrogen target tissue. As both reproductive and urinary systems arise from the same germinal ridge, we propose that some of the germinal cells, normally destined for the uterus, migrate and establish themselves in the renal corticomedullary region in this hamster strain. These ectopically located germinal cells remain dormant unless exposed to estrogen. Supporting this contention, a subset of renal interstitial cells, primarily located in the corticomedullary region, express PR after only 2 wk and ER alpha after 1.5--3.0 months of estrogen treatment. As treatment continues, groups of cells of the renal interstitium and small and large renal tumors show ER alpha(+) and PR(+) staining. Although ER alpha and PR isoform profiles in estrogen-treated hamster kidneys are distinctly different from corresponding uterine patterns, both receptor isoform profiles in primary renal tumors closely resemble those seen in hamster uteri. Renal ER alpha protein and mRNA expression increased after 2.0 and 4.0 months of estrogen treatment and in all renal tumors examined. Using nuclear image cytometry, both early small and large renal tumors were highly aneuploid, indicating that genomic instability is probably a critical early event in estrogen carcinogenesis.

Aneuploidy↗
PubMed2001

Down-regulation of cell adhesion molecules LFA-1 and ICAM-1 after in vitro treatment with the anti-TNF-alpha agent thalidomide.

The tumor necrosis factor-alpha (TNF-alpha) inhibitor thalidomide is known to be a potent modulator of host immunity, a potential treatment for autoimmune disorders such as rheumatoid arthritis (RA) and a treatment for complications of HIV-1 infection. RA is an autoimmune disease of the joints that has been associated with hyperactivity of lymphocytes and other leukocytes, over-expression of pro-inflammatory cytokines (TNF-alpha and IL-1) and chronic debilitating inflammation. Thalidomide may play a role in RA treatment by altering leukocyte function through down-modulation of cell adhesion molecules necessary for leukocyte migration to inflammatory sites. The present study investigates down-regulation of cell adhesion molecules (ICAM-1 and LFA-1) and decreases in cell-cell contacts between human T leukemic (CEM) cells and human umbilical vein endothelial cells (HUVEC) after thalidomide exposure. CEM cells were cultured in RPMI 1640 medium with 0, 10 or 50 microg/ml thalidomide, stained with fluorescent monoclonal antibodies specific to ICAM-1 and LFA-1 and expression was measured with flow cytometry. For cell-cell adhesion measurements, monolayers of HUVEC cultured in Kaign's F-12 medium were incubated with thalidomide treated CEM cells stained with calcein AM. Specific cell adhesion between the two cell types was visualized with fluorescence microscopy. Thalidomide treatment significantly reduced cell adhesion molecule expression in a dose-dependent fashion and inhibited HUVEC/CEM cell adhesion. These data support the hypothesis that thalidomide has modulatory actions on leukocyte functions through expression of cell adhesion molecules.

Cell Adhesion↗
PubMed2000

Metacarpophalangeal pattern profile analysis in Noonan syndrome.

Metacarpophalangeal pattern (MCPP) analysis is an application of an anthropometric technique that provides a quantitative assessment of the amount and direction of abnormality in the hand skeleton. MCPP analysis was undertaken on 15 individuals (9 males, 6 females) with Noonan syndrome ranging in age from 0.1 to 36 years with a mean age at 11.6 years. The overall average Z score for the MCPP variables was -2.1 and the range was -2.5 (for metacarpal two) and -1.5 (for middle phalanx 5). The average hand pattern variability index, a measure of hand bone length relationships, was abnormal. A Pearsonian correlation analysis was used to assess similarity between the mean pattern and each of the 15 individual patterns. Nine (60%) of the fifteen individuals with Noonan syndrome had significant positive correlations (P < 0.05), indicating homogeneity or similarity in the hand patterns. A stepwise discriminant analysis was performed on Z score data from the individual hand bone measurements on the 15 subjects with Noonan syndrome and 41 healthy controls (24 females, 17 males; mean age = 13.1 years with age range of 9.6 to 18 years). This analysis produced a discriminant function with two MCPP variables (metacarpal 1 and middle phalanx 3) entering into the function and producing a correct classification rate of 93%. The two MCPP variables contributed to the overall difference between individuals with Noonan syndrome and the normative sample. The hand pattern variability index was outside of the normal range, indicating an abnormal MCPP with multivariate analysis. The MCPP analysis may be useful as a tool for diagnosis in screening subjects for Noonan syndrome.

Adolescent↗
PubMed2000

Aminolevulinic acid-induced photodynamic therapy: safe and effective ablation of dysplasia in Barrett's esophagus.

Photodynamic therapy (PDT) is a treatment in which cell damage is achieved by the action of light on a photosensitizer. The aim of this study was to assess the value of PDT in the treatment of Barrett's esophagus with low-grade dysplasia (LGD). Forty patients with dysplastic Barrett's esophagus were given aminolevulinic acid (ALA) 30 mg/kg orally followed 4 h later by laser endoscopy. Follow-up endoscopy and biopsies were performed at 1, 6 and 12 months. A macroscopic response was seen in 33 out of 40 patients, with a median decrease in columnar epithelial area of 30% (range 0-90%). Post-treatment biopsies showed no dysplasia in 39 out of 40 patients, with LGD remaining in one case. This was maintained at 6 and 12 months. There were no significant side-effects. This study demonstrates that ALA-induced PDT provides safe and effective ablation therapy for Barrett's esophagus and is particularly useful against dysplasia.

Aminolevulinic Acid↗
PubMed2000

Photodynamic therapy for dysplastic Barrett's oesophagus: a prospective, double blind, randomised, placebo controlled trial.

BACKGROUND AND AIMS: Photodynamic therapy (PDT) is a treatment in which cell damage is achieved by the action of light on a photosensitizing agent. We have assessed the potential use of PDT in the ablation of Barrett's oesophagus. METHODS: Thirty six patients with dysplastic Barrett's oesophagus receiving acid suppression medication with omeprazole were randomised to receive oral 5-aminolaevulinic acid (ALA) 30 mg/kg or placebo, followed four hours later by laser endoscopy. Follow up endoscopy was performed at one, six, 12, and 24 months. RESULTS: Of 18 patients in the ALA group, a response was seen in 16 (median decrease in area in the treated region 30%; range 0-60%). In the placebo group, a decrease in area of 10% was observed in two patients with no change in 16 (median 0%; range 0-10%; treatment v placebo, p<0.001). No dysplasia was seen in the columnar epithelium within the treatment area of any patient in the PDT group. However, in the placebo group, persistent low grade dysplasia was found in 12 patients (p<0.001). There were no short or long term major side effects. The effects of treatment were maintained for up to 24 months. CONCLUSIONS: This is the first randomised controlled trial of PDT for Barrett's oesophagus. It demonstrates that ALA induced PDT can provide safe and effective ablation of low grade dysplastic epithelium.

Adult↗
PubMed1997

Factors influencing age at referral of children with congenital heart disease.

OBJECTIVES: To chronicle current referral practices for children with congenital cardiac disease and to determine which factors (lesion, physician type, insurance, or physician location) influenced the age at referral. METHODS: Data were collected from our congenital cardiac registry for all children born from January 1, 1989, through December 31, 1994, with 1 of 4 isolated lesions: valvular aortic stenosis, secundum atrial septal defect, tetralogy of Fallot, and ventricular septal defect. Variables included insurance plan at referral, referring physician (nonpediatrician vs pediatrician), and physician location (urban vs nonurban). RESULTS: The study population included 544 children. In the neonatal period, mean age at referral was 9 days for patients with private insurance and those with managed care. Nonurban neonates were referred a mean of 5.2 days later than urban neonates. After the neonatal period, those with managed care were referred later (279 days) than those with commercial insurance (165 days). Mean nonurban referral age was 213 days vs 136 days for urban referrals (P=.008). After the neonatal period, mean age at referral increased progressively each year for those with managed care. Mean referral age by all nonpediatricians was 222 days vs 136 days for all pediatricians (P=.008), but nonurban pediatricians referred patients at a similar age as nonpediatricians. CONCLUSIONS: For neonates the major risk factor for delayed referral was nonurban location; for the whole group, major risk factors were insurance other than commercial, nonurban location, and lesion type.

Age Factors↗
PubMed1995

Bystander cardiopulmonary resuscitation. Concerns about mouth-to-mouth contact.

BACKGROUND: Bystander cardiopulmonary resuscitation (CPR) is performed on only a small percentage of patients who suffer cardiac arrest. We conducted a study to elucidate attitudes toward and potential obstacles to performance of bystander CPR. METHODS: Attitude survey of 975 people on the University Heart Center, University of Arizona, Tucson, mailing list. Participants were asked about their willingness to perform CPR under four conditions, with varying relationships (stranger vs relative or friend) and CPR techniques (chest compressions plus mouth-to-mouth ventilation [CC+V] vs chest compressions alone [CC]). RESULTS: Participants rated willingness to perform CPR and concern about disease transmission. Both relationship and CPR technique affected willingness to respond. Only 15% would "definitely" provide CC+V with strangers compared with 68% who would "definitely" perform CC. Even with relatives or friends, only 74% would "definitely" provide CC+V compared with 88% who would "definitely" provide CC. Eighty-two percent of participants were at least "moderately" concerned about disease transmission. CONCLUSION: Concerns regarding mouth-to-mouth ventilation appear to create substantial barriers to performance of bystander CPR. Intensified educational efforts and investigations of new approaches to bystander CPR are warranted.

Adult↗
PubMed1995

Relationship between mast cell degranulation and inflammation in the oral cavity.

Mast cells are granule-containing secretory cells which are distributed preferentially about the microvascular bed in oral mucosa. This work examined the contribution of mast cell mediators to inflammation in the oral cavity. Mast cells in oral tissues expressed the serine proteases, tryptase and chymase, with a minor subpopulation being chymase-negative. Mast cells contained the cytokine tumour necrosis factor-alpha (TNF) in their granules. Degranulation of mast cells was a consistent feature of inflammatory lesions (lichen planus, gingivitis, pulpitis, periapical inflammation). In lichen planus, intracellular stores of TNF were depleted, and expression of mRNA for TNF was upregulated, indicating ongoing production and release of the cytokine. The density of mast cells in tissue compartments was related to the level of expression of E-selectin, an endothelial adhesion molecule which is known to be induced in skin by TNF derived from degranulating mast cells. Further attention should be directed toward the role of mast cell products, particularly TNF, in inflammation in the oral cavity.

Cell Count↗
PubMed1984

An overview and analysis of the Health Style campaign.

In 1981, the Office of Health Information and Health Promotion of the U.S. Department of Health and Human Services launched a national health promotion media campaign titled Health Style. The purposes of the Health Style campaign were: to increase public awareness of the effects of life-style on health; to enable persons to assess which life-style changes would be most conducive to their health; to stimulate information-seeking behavior and; to foster the development of local health promotion activities and referral networks. The campaign was implemented in nine test communities across the United States. This article: provides an overview of the campaign; examines strategies used to implement the campaign in three local communities and; presents the findings of evaluations conducted at both the national and local levels. A summary of lessons learned from the Health Style campaign experience is included in the article.

Colorado↗
PubMedDate not supplied

Welfare reform: a women's health perspective.

Welfare reform programs currently being considered and implemented by the federal government and the states pose serious risks to poor women's health. Many of the proposed reforms, such as inflexible work requirements and time limits that threaten to reduce or eliminate current benefits, will make it more difficult for women to leave abusive relationships and will exacerbate the risks associated with violence against women. Other proposals target women's reproductive behavior. Programs that, for example, deny welfare benefits to teen mothers or to children born to women on welfare, increase the emotional stress experienced by poor pregnant women and may effectively coerce some women to seek abortions they would not otherwise choose. Benefit cuts also exacerbate the well-documented ill effects of poverty on children and families. The goals of welfare reform-increasing work participation and reducing poverty-can be more effectively achieved by means that do not pose these serious health risks to poor women.

Adolescent↗
PubMedDate not supplied

Occupational health and safety information systems in the pharmaceutical industry.

This chapter outlines a health and safety management system that encompasses all of the work environments in a pharmaceutical company, including the laboratory, manufacturing, sales, and corporate forces. It discusses information flow and integration to address physical, biological, and chemical hazards present.

Computer Communication Networks↗