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Biomedical subjects

D Anderson

Publications and source records attributed to D Anderson.

At least 91 records · Page 5Linked to original sources
PubMed2000

Comparison of polyvinyl alcohol fixative with three less hazardous fixatives for detection and identification of intestinal parasites.

Polyvinyl alcohol (PVA) containing the fixative mercuric chloride is considered the "gold standard" for the fixation of ova and parasites in the preparation of permanently stained smears of stool specimens. However, mercuric chloride is potentially hazardous to laboratory personnel and presents disposal problems. We compared three new alternative, nontoxic fixatives with PVA, analyzing ease of sample preparation and quality of smears. Sixty-eight fresh stool specimens were divided into aliquots and placed in each of four different fixatives: PARASAFE (PS) (Scientific Devices Laboratory, Inc., Des Plaines, Ill.), ECOFIX (EC) (Meridian Diagnostics, Inc., Cincinnati, Ohio), Proto-Fix (PF) (Alpha-Tec Systems, Inc., Vancouver, Wash.), and low-viscosity PVA fixative (PVA) (Meridian). Specimens were processed and stained according to each manufacturer's directions. Parasites were found in 31 of 68 slide preparations with PVA, 31 with PF, 30 with EC, and 30 with PS. Blastocystis hominis and Iodamoeba bütschlii were preserved in a readily identifiable state by all methods of fixation. However, some parasites were more easily identified with some of the fixatives because of differences in parasite distortion. For example, Entamoeba histolytica (Entamoeba dispar) was detected in 13 stools fixed with PF, 7 with PVA, and 6 with EC but none with PS. Likewise, Chilomastix mesnili was identified in 13 specimens fixed with PF, 8 with EC, and 5 with PVA but only 1 with PS, while Entamoeba coli was seen much less frequently with PS than with the other three fixatives. A dirty background was observed in 41% of specimens prepared with PS, whereas background quality was acceptable with other fixatives. Sample preparation was most rapid with PS, although the EC method involved the fewest steps. In conclusion, PVA and PF produced the least parasite distortion, while PS proved unsatisfactory for the identification of E. histolytica, E. coli, and C. mesnili. Both PF and EC appear to be acceptable, environmentally safe substitutes for PVA.

Animals↗
PubMed2000

Osteoclasts expressing the measles virus nucleocapsid gene display a pagetic phenotype.

Osteoclasts (OCLs) in Paget's disease are markedly increased in number and size, have increased numbers of nuclei per multinucleated cell, and demonstrate increased resorption capacity and increased sensitivity to 1,25-(OH)(2)D(3), the active form of vitamin D. These cells also contain nuclear inclusions, reminiscent of those seen in paramyxovirus-infected cells, which cross-react with antibodies to measles virus nucleocapsid (MVNP) antigen. To elucidate the role of MV in the abnormal OCL phenotype of Paget's disease, we transduced normal OCL precursors with retroviral vectors expressing MVNP and the MV matrix (MVM) genes. The transduced cells were then cultured with 1,25-(OH)(2)D(3) for14 or 21 days to induce formation of OCL-like multinucleated cells. The MVNP-transduced cells formed increased numbers of multinucleated cells, which contained many more nuclei and had increased resorption capacity compared with multinucleated cells derived from empty vector-transduced (EV-transduced) and MVM-transduced or normal bone marrow cells. Furthermore, MVNP-transduced cells showed increased sensitivity to 1, 25-(OH)(2)D(3), and formed OCLs at concentrations of 1, 25-(OH)(2)D(3) that were 1 log lower than that required for normal, EV-transduced, or MVM-transduced cells. These results demonstrate that expression of the MVNP gene in normal OCL precursors stimulates OCL formation and induces OCLs that express a phenotype similar to that of pagetic OCLs. These results support a potential pathophysiologic role for MV infection in the abnormal OCL activity and morphology that are characteristic of pagetic OCLs.

Bone Marrow Cells↗
PubMed2000

Enhanced RANK ligand expression and responsivity of bone marrow cells in Paget's disease of bone.

Paget's disease is characterized by highly localized areas of increased osteoclast (OCL) activity. This suggests that the microenvironment in pagetic lesions is highly osteoclastogenic, or that OCL precursors in these lesions are hyperresponsive to osteoclastogenic factors (or both). To examine these possibilities, we compared RANK ligand (RANKL) mRNA expression in a marrow stromal cell line developed from a pagetic lesion (PSV10) with that in a normal stromal cell line (Saka), and expression in marrow samples from affected bones of Paget's patients with that in normal marrow. RANKL mRNA was increased in PSV10 cells and pagetic marrow compared with Saka cells and normal marrow, and was also increased in marrow from affected bones compared with uninvolved bones from Paget's patients. Furthermore, pagetic marrow cells formed OCLs at much lower RANKL concentrations than did normal marrow. Anti-IL-6 decreased the RANKL responsivity of pagetic marrow to normal levels, whereas addition of IL-6 to normal marrow enhanced RANKL responsivity. Thus, RANKL expression and responsivity is increased in pagetic lesions, in part mediated by IL-6. These data suggest that the combination of enhanced expression of RANKL in affected bones and increased RANKL sensitivity of pagetic OCL precursors may contribute to the elevated numbers of OCLs in Paget's disease.

Antibodies↗
PubMed2000

Trainee characteristics and perceptions of HIV/AIDS training quality.

HIV/AIDS education and training have played a vital role in keeping health providers up to date on emerging developments and approaches. This study reports findings from seven HIV/AIDS education and training projects. Participants in more than 600 training sessions described themselves, their professional background, and their general reasons for taking the training. Immediately following the training, they also rated the quality of their educational experience along several dimensions. Trainee characteristics were related to assessments of training quality, using a regression decision-tree analytic approach. Although effect sizes were generally small, quality ratings of the HIV/AIDS training experiences were associated with certain projects, basic trainee demographic characteristics, professional background, and experience in the HIV field. Greater understanding about participant characteristics can provide clues about how these training experiences are perceived and processed and may inform decision making about instructional HIV/AIDS curricula.

Adult↗
PubMed2000

Alcohol and drug abuse in sexual and nonsexual violent offenders.

According to a literature review by Marshall (1996), presently available data have not clarified the proportion of sexual offenders who would meet diagnostic criteria for addictive problems. Our own literature review failed to find published studies comparing sexual offenders to nonsexual violent offenders on standardized measures of substance abuse. Our study is a preliminary investigation of the differences between sexual offenders (rapists: n = 72; child molesters: n = 34) and nonsexual violent offenders (n = 24) on measures of alcohol and drug abuse. The findings indicate that sexual offenders were more likely to abuse alcohol than were nonsexual violent offenders. Nonsexual offenders were significantly more likely to have had a history of other forms of substance abuse. The results are considered in terms of theories of alcohol's contribution to aggressive behavior and sexual aggression. Implications for assessment and treatment of sexual offenders are discussed.

Adult↗
PubMed2000

Hes6 acts in a positive feedback loop with the neurogenins to promote neuronal differentiation.

During the development of the vertebrate nervous system, neurogenesis is promoted by proneural bHLH proteins such as the neurogenins, which act as potent transcriptional activators of neuronal differentiation genes. The pattern by which these proteins promote neuronal differentiation is thought to be governed by inhibitors, including a class of transcriptional repressors called the WRPW-bHLH proteins, which are similar to Drosophila proteins encoded by hairy and genes in the enhancer of split complex (E-(SPL)-C). Here, we describe the isolation and characterization of Hes6, which encodes a novel WRPW-bHLH protein expressed during neurogenesis in mouse and Xenopus embryos. We show that Hes6 expression follows that of neurogenins but precedes that of the neuronal differentiation genes. We provide several lines of evidence to show that Hes6 expression occurs in developing neurons and is induced by the proneural bHLH proteins but not by the Notch pathway. When ectopically expressed in Xenopus embryos, Hes6 promotes neurogenesis. The properties of Hes6 distinguish it from other members of the WRPW-bHLH family in vertebrates, and suggest that it acts in a positive-feedback loop with the proneural bHLH proteins to promote neuronal differentiation.

Amino Acid Sequence↗
PubMed2000

Effects of iron salts and haemosiderin from a thalassaemia patient on oxygen radical damage as measured in the comet assay.

Thalassaemia is a group of genetic diseases where haemoglobin synthesis is impaired. This chronic anaemia leads to increased dietary iron absorption, which develops into iron overload pathology. Treatment through regular transfusions increases oxygen capacity but also provides iron through the red cells' haemoglobin. An essential treatment, in parallel with transfusions, is the use of chelating agents to remove the excess iron deposited in tissues. These deposits are found in the liver, spleen, heart, and pancreas and are associated with cardiac failure and diabetes. The deposits in these tissues of patients have been isolated as haemosiderin. Thalassaemia patients are particularly at risk of free radical induced damage. Thus, the present study has investigated, as a model system, human cells in vitro in the Comet assay in the presence of free radicals. This assay measures DNA damage, particularly DNA strand breakage. The effects of iron overload on cells oxidatively stressed with hydrogen peroxide (H(2)O(2)) have been determined as well as the effect of the chelating agent, deferoxamine. Iron overload was simulated with ferric (FeCl(3)) and ferrous chloride (FeCl(2)), ferrous sulphate (FeSO(4)) and haemosiderins. Both human lymphocytes from a male and a female donor and human adenocarcinoma colonic cells showed an increase in DNA damage in the Comet assay after treatment with H(2)O(2). Ferric chloride produced an increase in DNA damage in human colonic cells, but little or no damage in human lymphocytes. Ferrous chloride also produced weak DNA damage in human lymphocytes, but ferrous sulphate produced a dose-related response. Deferoxamine produced no DNA damage. When H(2)O(2) was combined with FeCl(3), FeCl(2), or FeSO(4), the DNA damage produced was as least as great as or slightly greater than with H(2)O(2) alone. When deferoxamine was combined with H(2)O(2) and FeSO(4) there was a consistent decrease in response. There was little or no decrease in response when deferoxamine was combined with H(2)O(2) and FeCl(3) or FeCl(2), but at high (100-300microm) doses there were changes in the appearance of cellular DNA from Comet tails to dense centres surrounded by a diffuse area. This was probably as a consequence of chelation processes. Haemosiderin produced no damage. The three fractions of haemosiderin examined were of three different densities and from a Thai patient where the oxyhydroxide phase is the ferrihydrite. The colour change was similar to that for FeCl(3), but the level of the ferric ion in the haemosiderin was possibly too low in the sample to produce a response. The next stage is to examine peripheral lymphocytes from thalassaemic patients, with and without chelation therapy, whose cells may be more sensitive to simulated iron overload and to lower levels of haemosiderin. Teratogenesis Carcinog. Mutagen. 20:11-26, 2000.

Caco-2 Cells↗
PubMed2000

Outpatient treatment of pulmonary embolism with dalteparin.

BACKGROUND: Pulmonary embolism is a common complication of deep vein thrombosis. It has been established that low molecular weight heparin may be used to treat deep vein thrombosis or pulmonary embolism and randomized studies have established that outpatient management of deep vein thrombosis with low molecular weight heparin is at least as effective as in-hospital management with unfractionated heparin. METHODS: This was a prospective cohort study of eligible patients with pulmonary embolism managed as outpatients using dalteparin (200 U/kg s/c daily) for a minimum of five days and warfarin for 3 months. Outpatients included those managed exclusively out of hospital and those managed initially for 1-3 days as inpatients who then completed therapy out of hospital. Reasons for admission included hemodynamic instability; hypoxia requiring oxygen therapy; admission for another medical reason; severe pain requiring parenteral analgesia or high risk of major bleeding. Patients were followed for three months for clinically apparent recurrent venous thromboembolism and bleeding. RESULTS: Between three teaching hospitals, a total of 158 patients with pulmonary embolism were identified. Fifty patients were managed as inpatients and 108 as outpatients. Of the outpatients, 27 were managed for an average of 2.5 days as inpatients and then completed dalteparin therapy as outpatients. The remaining 81 patients were managed exclusively as outpatients with dalteparin. For all outpatients the overall symptomatic recurrence rate of venous thromboembolism was 5.6% (6/108) with only 1.9% (2/108) major bleeds. There were a total of four deaths with none due to pulmonary embolism or major bleed. CONCLUSIONS: This prospective study suggests that outpatient management of pulmonary embolism is feasible and safe for the majority of patients.

Adult↗
PubMed2000

Population of households in England to 2021.

This article outlines the methodology and results of the Department of the Environment, Transport and the Regions (DETR) 1996-based household projections for England, and its regions. It examines differences between this round of projections and the previous 1992-based round. The 1996-based projections indicate that between 1996 and 2021 a growth of 3.8 million households can be expected in England, if recent trends continue. Both the national and subnational methodology and results are covered.

Adolescent↗
PubMed2000

Risk factors for diethylstilbestrol-associated clear cell adenocarcinoma.

OBJECTIVE: To assess the influence of postnatal factors on the development of clear cell adenocarcinoma in women exposed to diethylstilbesterol (DES), particularly factors related to exogenous or endogenous hormone exposures, and to reassess the relation of season of birth. METHODS: For the analysis of postnatal factors, 244 cases were compared with 244 age-matched DES-exposed women. Information was obtained from telephone interviews, with questions asked in reference to an index age, the age at which clear cell adenocarcinoma was diagnosed. For the analysis of season of birth, 604 cases, living or deceased, were compared with 1749 DES-exposed women. RESULTS: Neither oral contraceptive (OC) use nor pregnancy was associated with risk of clear cell adenocarcinoma: the odds ratios (OR) were 1.1 (95% confidence interval [CI] 0.7, 1.8) for OC use and 1.3 (95% CI 0.7, 2.3) for pregnancy. The OR for fall season of birth relative to all other seasons was 1.2 (95% CI 0.9, 1.4). CONCLUSION: Pregnancy and OCs do not increase risk of DES-associated clear cell adenocarcinoma. In addition, season of birth does not appear to be a material factor; the previous finding of an increased risk for fall season of birth is most likely not valid and probably a chance finding due to small sample size.

Adenocarcinoma, Clear Cell↗
PubMed2000

Effects of HIV/AIDS education and training on patient care and provider practices: a cross-cutting evaluation.

Initial and continuing training in HIV/AIDS service provision is a critical way to enable the nation's health providers to use state-of-the-art developments and perspectives. Typically, the efficacy of HIV/AIDS training programs is evaluated using assessments administered to trainees immediately following the training. This study reports cross-cutting findings from telephone interviews conducted with 218 trainees an average of 8 months after training. Long-term training effects are examined in three domains: (a) general perspectives on HIV/AIDS; (b) health care provider service provision; and (c) changes in procedures and operations at the health care system level. The findings show the different ways that the training experience had long-term positive and observable effects in these three domains. In some cases, background characteristics and job positions predicted the specific type of reported training effects. The pattern of results suggests ways in which training methods can be targeted to specific audiences.

Acquired Immunodeficiency Syndrome↗
PubMed2000

Do characteristics of HIV/AIDS education and training affect perceived training quality? Lessons from the evaluation of seven projects.

Initial and continuing HIV/AIDS education and training has been a critical way to bring the nation's health providers up to date on emerging developments and approaches. This study reports cross-cutting findings from seven HIV/AIDS education and training projects. Trainers described over 600 training sessions from these projects in terms of their structural characteristics and design elements, while trainees described these sessions on several dimensions related to training quality. Training characteristics were compared to trainee assessments of training quality. Using a decision-tree analytic approach for major training attributes, considerable support emerged for links between training characteristics and perceived quality of the HIV/AIDS training experience. More favorable quality ratings were associated with certain projects, the training setting, the types of trainees served by the training, the intended training impact, discussion of special populations, and training methods involving interactive learning. With increased knowledge regarding how these educational experiences relate to the ways they are perceived and processed, more targeted approaches to training design on HIV/AIDS can be developed.

Adult↗
PubMed2000

Abusive behavior is barrier to high-reliability health care systems, culture of patient safety.

Addressing abusive behavior in the medical workplace presents an important opportunity to deliver on the national commitment to improve patient safety. Fundamentally, the issue of patient safety and the issue of abusive behavior in the workplace are both about harm. Undiagnosed and untreated, abusive behavior is a barrier to creating high reliability service delivery systems that ensure patient safety. Health care managers and clinicians need to improve their awareness, knowledge, and understanding of the issue of workplace abuse. The available research suggests there is a high prevalence of workplace abuse in medicine. Both administrators at the blunt end and clinicians at the sharp end should consider learning new approaches to defining and treating the problem of workplace abuse. Eliminating abusive behavior has positive implications for preventing and controlling medical injury and improving organizational performance.

Agonistic Behavior↗
PubMed1999

Cytogenetic damage and ras p21 oncoprotein levels from patients with chronic obstructive pulmonary disease (COPD), untreated lung cancer and healthy controls.

The purpose of the present communication was to determine in patients with chronic obstructive pulmonary disease (COPD), untreated lung cancer and healthy controls if there was a possible association between the disease state and biomarkers of cytogenetic damage and ras p21 oncoprotein levels, and if various exogenous confounding factors such as smoking habit and endogenous ones (sex, cancer in the immediate family) could affect these biomarkers. The individuals in all groups were as well-matched as possible for age to determine if this could be eliminated as a confounder. Peripheral blood and plasma were collected from 20 COPD patients, 31 cancer patients and 20 healthy controls. Chromosomal aberrations (CA), sister chromatid exchanges (SCE) and high frequency SCE cells (HFC) were examined from the blood and ras p21 oncoproteins from the plasma. These parameters were used as biomarkers of genotoxic anomalies. All the biomarkers were examined for their relationship to the confounding factors. Results were analysed by a t-test, analysis of variance (ANOVA) and stepwise multivariate regression analysis. There was an increase in CA, although not statistically so, in COPD and cancer patients by comparison with healthy controls, but there was a statistically significant increase in SCE, HFC and ras p21 oncoproteins. There was also a statistically significant difference between respiratory volume parameters in COPD patients and controls. Respiratory parameters were not measured in cancer patients. Ras p21 oncoproteins were also statistically significantly increased in the COPD and cancer patients, suggesting that the disease state alone might be sufficient to increase the oncoproteins, or that some of the COPD patients were in the process of developing cancer or perhaps some would die from COPD before cancer developed. Smoking was shown to have a marked effect on all parameters investigated. Ex-smokers showed less effects. Since age was very well controlled, there was little effect due to age. There was an effect due to sex, but cancer in the immediate family had little effect on any of the parameters.

Adult↗
PubMed1999

IL-2 plasmid therapy of murine ovarian carcinoma inhibits the growth of tumor ascites and alters its cytokine profile.

We have evaluated whether i.p. murine ovarian tumors could be treated with an IL-2 plasmid DNA complexed with the cationic lipid, (+/-)-N-(2-hydroxyethyl)-N,N-dimethyl-2, 3-bis(tetradecyloxy)-1-propanaminium bromide/dioleoylphosphatidylethanolamine (DMRIE/DOPE). Reporter gene studies were initially conducted in which mice bearing i.p. murine ovarian teratocarcinoma (MOT) were injected i.p. with reporter gene plasmid DNA (pDNA):DMRIE/DOPE. Histochemical analyses revealed that transfection occurred primarily in the tumor cells of the ascites, with only a minority of other ascitic cells or surrounding tissues transfected. IL-2 levels in the MOT ascites were determined after i. p. injection of either IL-2 pDNA:DMRIE/DOPE or recombinant IL-2 protein. IL-2 was detected in tumor ascites for up to 10 days after a single i.p. injection of IL-2 pDNA:DMRIE/DOPE, but was undetectable 24 h after a single i.p. injection of IL-2 protein. In an antitumor efficacy study, MOT tumor-bearing mice injected i.p. with IL-2 pDNA:DMRIE/DOPE on days 5, 8, and 11 after tumor cell implant had a significant inhibition of tumor ascites (p = 0.001) as well as a significant increase in survival (p = 0.008). A cytokine profile of the MOT tumor ascites revealed that mice treated with IL-2 pDNA:DMRIE/DOPE had an IL-2-specific increase in the levels of IFN-gamma and GM-CSF. Taken together, these findings indicate that i. p. treatment of ovarian tumors with IL-2 pDNA:DMRIE/DOPE can lead to an increase in local IL-2 levels, a change in the cytokine profile of the tumor ascites, and a significant antitumor effect.

Animals↗
PubMed1999

Examination of ras oncoproteins in human plasma from healthy controls and workers exposed to petroleum emissions, including benzene-related compounds.

Ras oncoproteins in blood plasma from workers exposed to petroleum emissions and unexposed controls were examined from Polish and Estonian samples. Twenty-four workers and 35 unexposed controls were examined from Poland and 97 exposed and 40 unexposed controls from Estonia. Of the Estonian workers, 50 were exposed to benzene in a benzene production plant and 47 to polyaromatic hydrocarbons and benzene in a cokery. Blood plasma proteins were separated by gel electrophoresis, transferred to a nitrocellulose membrane by Western blotting and detected by chemiluminescence using a monoclonal antibody as the primary antibody. There were no statistically significant differences between the exposed and the control groups in either the Polish or the Estonian samples.

Air Pollutants, Occupational↗
PubMed1999

Therapeutic plasma exchange: an update from the Canadian Apheresis Group.

In 1997, the Canadian Apheresis Group reviewed data on 103,416 plasma exchange procedures that had been collected since 1980. Although the number of plasma exchanges gradually increased (from 3189 to 8208 per year), the pattern changed. In 1981, the five most frequent indications for plasma exchange resulted in 55% of all such procedures; by 1997, the five most frequent indications for plasma exchange resulted in 81.1% of all such procedures. During this period, three conditions that were originally among the most frequent indications for plasma exchange became among the least frequent. This paper reviews the published evidence that supports or refutes the use of plasma exchange in the category of the five most frequent indications from 1981 to 1997: thrombotic thrombocytopenic purpura, myasthenia gravis, chronic inflammatory demyelinating polyneuropathy, Waldenstrom macroglobulinemia, the Guillain-Barre syndrome, rheumatoid arthritis, systemic lupus erythematosus, and multiple sclerosis. For most disorders, use of plasma exchange procedures is correlated with published evidence, and the changing patterns of plasma exchange use by members of the Canadian Apheresis Group reflect published evidence. Annual center-by-center reviews of use of plasma exchange may also have influenced practice patterns.

Acute Disease↗