Search PubMed⌕ Search

Biomedical subjects

J Donnelly

Publications and source records attributed to J Donnelly.

At least 73 records · Page 4Linked to original sources
PubMed1995

Effect of impact stress on microbial recovery on an agar surface.

Microbial stress due to the impaction of microorganisms onto an agar collection surface was studied experimentally. The relative recovery rates of aerosolized Pseudomonas fluorescens and Micrococcus luteus were determined as a function of the impaction velocity by using a moving agar slide impactor operating over a flow rate range from 3.8 to 40 liters/min yielding impaction velocities from 24 to 250 m/s. As a reference, the sixth stage of the Andersen Six-Stage Viable Particle Sizing Sampler was used at its operating flow rate of 28.3 liters/min (24 m/s). At a collection efficiency of close to 100% for the agar slide impactor, an increase in sampling flow rate and, therefore, in impaction velocity produced a significant decline in the percentage of microorganisms recovered. Conversely, when the collection efficiency was less than 100%, greater recovery and lower injury rates occurred. The highest relative rate of recovery (approximately 51% for P. fluorescens and approximately 62% for M. luteus) was obtained on the complete (Trypticase soy agar) medium at 40 and 24 m/s (6.4 and 3.8 liters/min), respectively. M. luteus demonstrated less damage than P. fluorescens, suggesting the hardy nature of the gram-positive strain versus that of the gram-negative microorganism. Comparison of results from the agar slide and Andersen impactors at the same sampling velocity showed that recovery and injury due to collection depends not only on the magnitude of the impaction velocity but also on the degree to which the microorganisms may be embedded in the collection medium.(ABSTRACT TRUNCATED AT 250 WORDS)

Aerosols↗
PubMed1995

Genetic and biochemical normalization in female carriers of Duchenne muscular dystrophy: evidence for failure of dystrophin production in dystrophin-competent myonuclei.

We studied 19 symptomatic female carriers of the Duchenne muscular dystrophy (DMD) gene. Most of these dystrophinopathy patients had had an erroneous or ambiguous diagnosis prior to dystrophin immunofluorescence testing. We assessed clinical severity by a standardized protocol, measured X-chromosome inactivation patterns in blood and muscle DNA, and quantitated the dystrophin protein content of muscle. We found that patients could be separated into two groups: those showing equal numbers of normal and mutant dystrophin genes in peripheral blood DNA ("random" X-inactivation), and those showing preferential use of the mutant dystrophin gene ("skewed" X-inactivation). In the random X-inactivation carriers, the clinical phenotype ranged from asymptomatic to mild disability, the dystrophin content of muscle was > 60% of normal, and there were only minor histopathologic changes. In the skewed X-inactivation patients, clinical manifestations ranged from mild to severe, but the patients with mild disease were young (5 to 10 years old). The low levels of dystrophin (< 30% on average) and the severe symptoms of the older patients suggested a poor prognosis for those with skewed X-inactivation, and they all showed morphologic changes of dystrophy. The random inactivation patients showed evidence of biochemical "normalization," with higher dystrophin content in muscle than predicted by the number of normal dystrophin genes. Seventy-nine percent of skewed X-inactivation patients (11/14) showed genetic "normalization," with proportionally more dystrophin-positive nuclei in muscle than in blood. In 65% of the skewed X-inactivation patients, dystrophin was not produced by dystrophin-positive nuclei; an average of 20% of myofiber nuclei were genetically dystrophin-positive but did not produce stable dystrophin. Biochemical normalization seems to be the main mechanism for rescue of fibers from dystrophin deficiency in the random X-inactivation patients. In the skewed X-inactivation patients, genetic normalization is active, but production failure of dystrophin by dystrophin-normal nuclei may counteract any effect of biochemical normalization. In the skewed X-inactivation patients, the remodeling of the muscle through cycles of degeneration and regeneration led to threefold increase in the number of dystrophin-competent nuclei in muscle myofibers (3.3 +/- 4.6), while dystrophin content was on the average 1.5-fold less then expected (-1.54 +/- 3.38). Our results permit more accurate prognistic assessment of isolated female dystrophinopathy patients and provide important data with which to estimate the potential effect of gene delivery (gene therapy) in DMD.

Adult↗
PubMed1994

Impaction onto a Glass Slide or Agar versus Impingement into a Liquid for the Collection and Recovery of Airborne Microorganisms.

To study impaction versus impingement for the collection and recovery of viable airborne microorganisms, three new bioaerosol samplers have been designed and built. They differ from each other by the medium onto which the bioaerosol particles are collected (glass, agar, and liquid) but have the same inlet and collection geometries and the same sampling flow rate. The bioaerosol concentrations recorded by three different collection techniques have been compared with each other: impaction onto a glass slide, impaction onto an agar medium, and impingement into a liquid. It was found that the particle collection efficiency of agar slide impaction depends on the concentration of agar in the collection medium and on the sampling time, when samples are collected on a nonmoving agar slide. Impingement into a liquid showed anomalous behavior with respect to the sampling flow rate. Optimal sampling conditions in which all three new samplers exhibit the same overall sampling efficiency for nonbiological particles have been established. Inlet and collection efficiencies of about 100% have been achieved for all three devices at a sampling flow rate of 10 liters/min. The new agar slide impactor and the new impinger were then used to study the biological factors affecting the overall sampling efficiency. Laboratory experiments on the total recovery of a typical environmental microorganism, Pseudomonas fluorescens ATCC 13525, showed that both sampling methods, impaction and impingement, provided essentially the same total recovery when relatively nonstressed microorganisms were sampled under optimal sampling conditions. Comparison tests of the newly developed bioaerosol samplers with those commercially available showed that the incorporation of our research findings into the design of the new samplers yields better performance data than data from currently available samplers.

Journal Article↗
PubMed1993

Aerosol penetration and leakage characteristics of masks used in the health care industry.

BACKGROUND: Historically, surgical masks have been worn to protect patients from being infected by large, pathogen-containing aerosol droplets emitted by health care personnel. Today, emphasis has shifted from solely protecting the patient to protecting the health care worker as well. As a result of new procedures used in operating rooms and clinical areas, aerosolized hazardous agents in the submicrometer size range are being produced, posing a potential threat to health care workers. METHODS: Eight surgical masks were tested for aerosol particle penetration through their filter media and through induced face-seal leaks. RESULTS: The percentage of filter penetration ranged from 20% to nearly 100% for submicrometer-sized particles. In comparison, a dust-mist-fume respirator used in industrial settings had significantly less penetration through its filter medium. When the surgical masks had artificially induced face-seal leaks, the concentration of submicrometer-sized particles inside the mask increased slightly; in contrast, the more protective dust-mist-fume respirator showed a fourfold increase in aerosol penetration into the mask with an artificial leak 4 mm in diameter. CONCLUSION: We conclude that the protection provided by surgical masks may be insufficient in environments containing potentially hazardous submicrometer-sized aerosols.

Aerosols↗
PubMed1993

Disagreements in discharge planning: a normative phenomenon.

The process of discharge planning is often impeded by disagreements among family members and others involved. A discharge plan must be negotiated to meet the varying needs of participants within the context of regulatory and organizational mandates. Under such circumstances, disagreements in decision making can be anticipated, particularly for family members, who must readjust roles and relationships in the face of the crisis of illness. Support for this conceptual formulation is found in the literature, particularly in two studies that evaluated the incidence of disagreements in discharge planning caseloads. In both studies, disagreements occurred in at least one-third of the cases, with most disagreements involving family members. Neither study found substantial disagreement among professionals. Social workers who provide discharge planning services in hospitals clearly are dealing with substantial levels of disagreements among principals in the process; in fact, disagreement needs to be accepted as a normative phenomenon in such planning. This article discusses the sources of family disagreements related to discharge planning, identifies the implications for social work practice, and uses a family systems perspective to articulate an approach to intervention.

Decision Making↗
PubMed1992

Improving self-care among older patients with type II diabetes: the "Sixty Something..." Study.

A 10-session, self-management training program was designed specifically for persons over 60 years of age having Type II diabetes. It targeted social learning variables, especially problem-solving skills and self-efficacy, found to be related to diabetes self-care in earlier correlational research. One hundred two adults were randomized to immediate or delayed intervention conditions. At posttest, subjects in the immediate intervention condition showed significantly greater reductions in caloric intake and percent of calories from fat than control subjects. The intervention also produced greater weight reductions and increases in the frequency of glucose testing than did the control condition. Improvements among immediate intervention subjects were generally maintained at a 6-month follow-up. Intervention results from subjects receiving delayed intervention closely replicated those for immediate intervention subjects. We conclude that a relatively short-term program can improve self-management skills of older diabetic adults, and that there is an important need for such interventions.

Aged↗
PubMed1991

Cryopreserved platelets have decreased adhesive capacity.

The technique of freezing blood platelets has proven very useful in transfusion support of some patients who have become alloimmunized by prior transfusions. Although transfused frozen platelets have an acceptable life span in vivo, functional defects have been found when these cells were tested in vitro. The adhesive properties of frozen platelets were investigated by use of a modified Baumgartner chamber to perform paired perfusion studies of fresh versus frozen platelets or fresh versus 5-day-stored platelets from the same whole blood unit. Platelets were either frozen in liquid nitrogen with dimethyl sulfoxide as the cryopreservative or stored under standard blood bank conditions for 5 days. The freeze-thaw recovery of platelets was 73 +/- 8 percent. Frozen platelets exhibited a significant decrease in platelet adhesion as compared to fresh platelets from the same unit; adhesion of frozen platelets was only 53 percent of that of fresh platelets (p = 0.04). A slight, but insignificant decrease was noted with platelets stored for 5 days (86%, p = 0.197). These findings indicate that frozen-thawed platelets have a significant defect in adhesive capacity as compared to fresh platelets, and that platelets stored under blood bank conditions for 5 days maintain adhesive capacity well.

Blood Platelets↗
PubMed1991

The hemodynamics of thrombus formation in arteries.

Alterations in arterial blood flow are thought to predispose to thrombus formation, but the exact relationships have not been fully elucidated. The effect of varying blood flows on the accumulation of thrombotic material within arteries was investigated, with use of shear rate as an index of flow across the luminal surface. Partially denuded rabbit aortas were perfused with fresh nonanticoagulated human blood for 3 minutes, with an in vitro recirculating apparatus, Indium 111-labeled platelets, and fibrinogen I 125. Shear rates ranged from zero to 1500 sec-1, correlating with the hemodynamics of various segments of the human arterial tree. A significant correlation was observed between shear rate and platelet deposition, ranging from 5.2 +/- 2.8 x 10(6) platelets/cm2 of vessel surface area at zero shear to a maximum of 64.7 +/- 8.3 x 10(6) platelets/cm2 at a shear rate of 1500 sec-1 (F = 5.01, p less than 0.05). Fibrin deposition paralleled that of platelets, ranging from 28.2 +/- 7.6 micrograms/cm2 at zero shear to 354.1 +/- 62.7 micrograms/cm2 at a shear rate of 1500 sec-1 (F = 5.91, p less than 0.05). These results suggest that shear rate is a most important determinant of platelet and fibrin deposition on altered arterial surfaces.

Animals↗
PubMed1991

Transsexualism.

Explore the source record for details and available documents.

Follow-Up Studies↗
PubMed1991

'The Barn'.

An exciting new concept in operating theatre suite design is being pioneered at the Robert Jones and Agnes Hunt Orthopaedic Hospital. Jane Donnelly visited 'The Barn' in February and reports on how the work is progressing.

Humans↗
PubMed1989

Diabetes-specific social learning variables and self-care behaviors among persons with type II diabetes.

This study assessed the relationship between diabetes-specific social learning factors and diabetes self-care. Predictor variables were collected within the categories of knowledge (e.g., behavioral demonstrations, pencil-and-paper tests), beliefs/expectations (e.g., self-efficacy, self-motivation), skills (e.g., problem-solving and refusal skills), and environmental support (e.g., barriers to adherence, family support). Different results emerged across the three areas of the regimen assessed: diet, exercise, and glucose testing. Multiple-regression analyses revealed that the social learning variables consistently improved the prediction of self-care beyond that attributable to demographic variables but that the categories of social learning variables most closely related to self-care varied across regimen areas. These findings suggest that programs to enhance diabetes self-care could beneficially focus on life-style behaviors and employ strategies to increase regimen-related expectations and diabetes-specific social and problem-solving skills.

Adult↗