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Biomedical subjects

J Perkins

Publications and source records attributed to J Perkins.

At least 55 records · Page 3Linked to original sources
PubMed1997

Mammographic screening: results from the 1996 National Breast Health Survey.

OBJECTIVE: To establish the extent of women's knowledge of mammographic screening, particularly in relation to the national screening program, BreastScreen Australia, and to estimate the proportion of women who are participating in screening both within and outside BreastScreen Australia. DESIGN AND SETTING: Validated prospective telephone survey of women aged 30-69 years selected at random from across Australia. PARTICIPANTS: 2935 women with no previous breast cancer diagnosis. RESULTS: The adjusted response rate was 64%. Almost 90% of women had heard of the national program; only 1% correctly stated that screening is for asymptomatic women. 60% correctly identified the current recommended age of starting screening is about 50 years of age; 26% thought screening should begin at about 40 years of age. Approximately 60% correctly reported that the recommended screening interval is every two years; 27% thought screening should be done annually. 55% reported ever having had a mammogram, and 37% reported having had at least one screening mammogram. Among women in the target age group (50-69 years) about 70% reported ever having had a screening mammogram, and about 50% reported having had a screening mammogram within the national program in the last two years. Among women aged 40-49 years, 29% reported ever having had a screening mammogram, and 22% reported having been screened in the last two years. CONCLUSIONS: Awareness of the national screening program is high, but some women do not know the purpose of screening, the target age group and the recommended screening interval. Compliance with screening is good among women in the target age group; many women in their 40s are also participating in screening.

Adult↗
PubMed1997

Expansion of donor hepatocytes after recombinant adenovirus-induced liver regeneration in mice.

Hepatocyte transplantation is a potential form of therapy for patients with genetic hepatodeficiency disorders. Unfortunately, hepatocellular transplantation has been limited because of the relatively low numbers of donor cells that can ultimately take up residence in the host liver. To give the donor cells a proliferative stimulus, a recombinant adenovirus vector that expresses a nonsecreted urokinase (urokinase-type plasminogen activator) was transduced into the livers of recipient animals before transplantation. Because urokinase production in hepatocytes causes the slow turnover of hepatocytes, 2 days after adenovirus-mediated gene transfer into the livers of recipient mice, 2 x 10(6) congenic donor cells tagged with beta-galactosidase (beta-Gal) reporter were implanted via the portal vein. As a result, on average, 8.6% of the recipient hepatocytes in the livers were derived from donor cells--a 20-fold increase compared with control animals in which no proliferative stimulus was present.

Adenoviridae↗
PubMed1996

Effects of a child abuse prevention unit in health classes in four schools.

The purpose of this study was to assess changes in parenting attitudes among high school students as an effect of a child abuse prevention unit taught in a required health class. Attitudes were measured using the Adult-Adolescent Parenting Inventory (AAPI), which was administered as a pretest-posttest. This was a primary prevention approach targeting students before they become parents. The unit consisted of an overview of child abuse, normal developmental expectations of children, anger management, and positive parenting techniques. Students from 4 schools participated in the study, and most students in the sample (N = 585) demonstrated healthy parenting attitudes. Low scores on multiple scales at pretest were recorded for 3.6% of the sample. Effect of intervention was measured using paired t tests, and a positive and statistically significant effect of intervention was noted, especially in 2 of 4 schools. Low-scoring students increased scores significantly although not up to mean pretest levels for the whole sample. Recommendations for further community health nursing research and educational initiatives are supported by these findings.

Adolescent↗
PubMed1996

Interpretation of facial expressions of emotion: the influence of eyebrows.

The contribution of the eyebrow component (eyebrow density and eyebrow position) in interpretation of facial displays of emotions was explored. In Study 1, college students (N = 60) and children (N = 60), ages 6-9 years, listened to vignettes consisting of one or two sentences and selected the facial expression that best matched the vignette. A main effect for eyebrow density as well as interactions for Density x Age and Density x Emotion were found. Also, a main effect for eyebrow position and interactions for Position x Age, Position x Emotion, and Position x Age x Emotion were significant. Study 2 was conducted to better understand whether findings regarding eyebrow position were a function of mistaking the intended emotion portrayed in the vignettes. Using a within-subject design, responses from 60 children, age 6-9 years, were compared for trials when the emotion was designated and when emotion was not designated. A main effect for designation of emotion was not found; however, an interaction effect for Designation x Emotion was significant.

Adolescent↗
PubMed1995

Adenovirus-mediated urokinase gene transfer induces liver regeneration and allows for efficient retrovirus transduction of hepatocytes in vivo.

Retrovirus-mediated gene transfer into hepatocytes in vivo results in long-term gene expression. Limitations include the need to remove two-thirds of the liver and the relatively low frequency of gene transfer. To increase gene transfer without surgical hepatectomy, mouse hepatocytes were transduced in vivo with a recombinant adenovirus that transiently expressed urokinase, resulting in high rates of asynchronous liver regeneration. During the regenerative phase, in vivo retroviral-mediated gene transfer in hepatocytes resulted in 5- to 10-fold greater transduction efficiencies than that obtained by conventional partial hepatectomy. In 3-4 weeks, the architecture and microscopic structure of the recipient livers were normal. The two-viral system of achieving permanent transgene expression from hepatocytes in vivo offers an alternative approach to current ex vivo and in vivo gene-transfer models.

Adenoviridae↗
PubMed1995

A modified urokinase plasminogen activator induces liver regeneration without bleeding.

Direct retrovirus-mediated hepatic gene transfer results in permanent gene expression; however, gene transfer requires surgical hepatectomy (to stimulate cell division) and has been inefficient. We recently used recombinant adenovirus vectors that transiently expressed urokinase from mouse hepatocytes to induce hepatocellular regeneration in place of a partial hepatectomy. The adenovirus method allowed for five-fold more efficient retrovirus transduction in vivo compared to the conventional partial hepatectomy approach. The major problem with the urokinase-mediated hepatic regeneration was the transient secretion of urokinase into the bloodstream that led to hypocoagulation. To circumvent this side-effect, the urokinase protein was modified by adding amino-terminal and carboxy-terminal endoplasmic reticulum retention signals. The recombinant urokinase molecules expressed from adenoviral vectors remained in hepatocytes, were enzymatically active, and resulted in similar rates of hepatic regeneration as found with the secreted urokinase. Modified urokinase-mediated liver regeneration was equally capable of allowing retrovirus-mediated gene transfer in vivo. Thus, the method of direct retrovirus transduction of hepatocytes becomes clinically relevant as the technology becomes safer.

Adenoviridae↗
PubMed1995

Cloning and characterization of the Bacillus subtilis birA gene encoding a repressor of the biotin operon.

The Bacillus subtilis birA gene, which regulates biotin biosynthesis, has been cloned and characterized. The birA gene maps at 202 degrees on the B. subtilis chromosome and encodes a 36,200-Da protein that is 27% identical to Escherichia coli BirA protein. Three independent mutations in birA that lead to deregulation of biotin synthesis alter single amino acids in the amino-terminal end of the protein. The amino-terminal region that is affected by these three birA mutations shows sequence similarity to the helix-turn-helix DNA binding motif previously identified in E. coli BirA protein. B. subtilis BirA protein also possesses biotin-protein ligase activity, as judged by its ability to complement a conditional lethal birA mutant of E. coli.

Amino Acid Sequence↗
PubMed1995

Factor XII deficiency and cardiopulmonary bypass.

Factor XII initiates the intrinsic coagulation cascade and may affect the fibrinolytic system. Routine coagulation tests used during cardiopulmonary bypass (CPB) are abnormal in factor-XII-deficient patients and are useless for monitoring anticoagulation in these patients. A factor-XII-deficient patient requiring CPB is described. The baseline celite activated clotting time (ACT) was greater than 1400 seconds and the thrombin time was 12.4 seconds (control, 11.9 seconds). Two units of plasma were given resulting in an ACT of 173 seconds. Following 300 units/kg of heparin and during CPB, the ACT ranged from 670-596 seconds with the thrombin time greater than 200 seconds. Plasma provides exogenous factor XII allowing an endpoint on the ACT test and may protect against possible postoperative hypofibrinolytic complications. A commercially available modified thrombin time may also be useful and provide an endpoint during high-dose heparinization.

Aged↗
PubMed1995

Strain related variations in adenovirally mediated transgene expression from mouse hepatocytes in vivo: comparisons between immunocompetent and immunodeficient inbred strains.

High efficiency gene transfer and gene expression in hepatocytes in vivo can be achieved using recombinant adenoviral vectors. However, the persistence of gene expression in different experimental animal models has been variable. To determine if similar differences could be observed in a single species, persistence of gene expression was studied in inbred strains of mice using a recombinant adenoviral vector that expresses human alpha 1-antitrypsin. Marked variability in the persistence of gene expression ranging from several weeks (C3H/HeJ and Balb/c) to more than 3 months [C57Bl/6, B10.A(2R) and B10.BR] was observed when this vector was transduced in different strains of inbred mice. This variability did not correlate with H-2 type. To evaluate the role of T and B cell immunity in the persistence of gene expression, congenic C3H-scid and Balb/c-scid mice were studied and found to have indefinite gene expression from transduced hepatocytes. These animals unlike their immunocompetent counter-parts were able to undergo secondary transduction of hepatocytes with a different recombinant adenoviral vector. These findings suggest that as yet unidentified genetic loci influence the persistence of adenovirus-mediated hepatic gene expression in vivo, and these effects are mediated at least in part, by the antigen specific immune system.

Adenoviridae↗
PubMed1994

Making interdisciplinary education effective for rehabilitation students.

Interdisciplinary education has been recommended as a way of preparing students for team practice after graduation. There is debate in the literature over the best way to implement interdisciplinary education sessions, and many factors can influence their effectiveness. This paper is a case description report of a pilot project developed to promote interdisciplinary learning. The Northern Studies Stream of McMaster University's School of Occupational Therapy and Physiotherapy in Ontario, Canada developed a project that combined students from the occupational therapy and physiotherapy programs for small group tutorials held during clinical placements. The project incorporated suggestions from the literature in order to encourage cooperation and interdisciplinary learning. Participants were mature, second-degree students with similar levels of clinical experience. The sessions were a required part of the academic course, but were ungraded. Tutorials focused on issues relevant to clinical practice for both groups and were facilitated by faculty from both professions. Evaluation was positive, suggesting student characteristics (eg, level of experience and maturity) and session design features that may be helpful in planning future interdisciplinary education experiences.

Humans↗
PubMed1993

Accumulation and intracellular compartmentation of lithium ions in Saccharomyces cerevisiae.

Accumulation of Li+ in Saccharomyces cerevisiae X2180-1B occurred via an apparent stoichiometric relationship of 1:1 (K+/Li+) when S. cerevisiae was incubated in the presence of 5 and 10 mM LiCl for 3 h. Other cellular cations (Mg2+, Ca2+ and Na+) did not vary on Li+ accumulation, although lithium chemistry dictates a degree of similarity to Group I and II metal cations. Compartmentation of Li+ was mainly in the vacuole which accounted for 85% of the Li+ accumulated after a 6-h incubation period. The remainder was located in the cytosol with negligible amounts being bound to cell fragments including the cell wall. Transmission electron microscopy of Li(+)-loaded cells revealed enlarged vacuoles compared with control cells. This asymmetric cellular distribution may therefore enhance tolerance of S. cerevisiae to Li+ and ensure that essential metabolic processes in the cytosol are not disrupted.

Cell Compartmentation↗
PubMed1993

Use of organic solvents and potential worker exposure in the motor vehicle manufacturing industry.

This survey was designed to assist with planning epidemiologic studies of the effects of solvent exposure among motor vehicle manufacturing workers. The objectives were to identify subgroups of workers with solvent exposure, and to evaluate the availability of data for a job-exposure matrix (JEM). Of 65 plants selected, 31 (48%) participated. Participant plants represent all production activities initially included in the survey, and employ 97,655 hourly workers. About 14% of these workers use organic solvents (direct exposure), and 19% work in the proximity of solvent-using operations (indirect exposure). However, only 3% have direct exposure, and 6% have indirect exposure to large-volume (> or = 100 gallons/month)/high-frequency (hourly)-use solvents. The highest solvent exposure prevalence occurs in plants manufacturing engines and power train components and in metal degreasing/cleaning and painting tasks, and entails exposure to petroleum fractions, aromatic hydrocarbons, alcohols, and ketones. A JEM can be developed using plant records on job titles, work histories, production scheduling, and plant engineering, and using the corporate computerized personnel and industrial hygiene databases. However, information on solvent use and on exposure is adequate only for recent time periods.

Automobiles↗
PubMed1993

Inter-rater agreement in the assessment of solvent exposure at a car assembly plant.

This study investigated the feasibility and the reproducibility of a retrospective assessment of solvent exposure in the painting operations of a car assembly plant. Five industrial hygienists (the raters) reviewed summary documents on plant operations and solvent exposure levels, developed from plant records and interviews. The raters independently reviewed 695 department-job-year combinations compiled from 29 work histories and used semi-quantitative scores to rate solvent exposure. Inter-rater agreement was evaluated by computing the percent concordance index and the intraclass correlation coefficient (rI). There was discordance among raters, a large proportion of which pertained to low exposure levels (1-5 ppm). The computation of the rI is sensitive to the distribution of exposure levels. A low rI can be observed for a rare exposure even if the percent concordance is high. Inter-rater agreement was good for cumulative exposure scores computed for frequent exposures: coatings (rI = 0.67), aromatic hydrocarbons (rI = 0.66), and petroleum distillates (rI = 0.62).

Automobiles↗
PubMed1993

Multi-modal hemispatial deficits after left hemisphere stroke. A disorder of attention?

We report a patient who, after suffering infarcts involving the left temporo-parietal and left anterior cingulate regions, performed significantly worse on a variety of motor, language and sensory tasks when he acted in or attended to right hemispace. Performance on a number of tasks was better when acting in near as compared with far peri-personal space and with his head deviated to the left as compared with the right. Additionally, performance with the 'unaffected' left hand was often worse in right as compared with left hemispace. We propose that his deficits are attributable to a disruption of a left hemisphere-specific attentional system which normally serves to regulate the activation and articulation of left hemisphere processing modules.

Adult↗