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Biomedical subjects

M Duffy

Publications and source records attributed to M Duffy.

At least 19 recordsLinked to original sources
PubMed2002

R-134a emissions from vehicles.

We report the first study of R-134a (also known as HFC-134a and CF3CFH2) refrigerant leakage from air conditioning (AC) systems of modern vehicles. Twenty-eight light duty vehicles from five manufacturers (Ford, Toyota, Daimler Chrysler, General Motors, and Honda) were tested according to the USEPA (Federal) extended diurnal test procedure using the Sealed Housing for Evaporative Determination (SHED) apparatus. All tests were conducted using stationary vehicles with the motor and air conditioning system turned off. R-134a was measured using gas chromatography (GC) with a flame ionization detector (FID). All vehicles exhibited measurable R-134a leakage over the 2-day diurnal test. Leak rates of R-134a ranged from 0.01 to 0.36 g/day with an average of 0.07+/-0.07 g/day. When combined with leakage associated with vehicle operation, servicing, and disposal we estimate that the lifetime average R-134a emission rate from an AC equipped vehicle is 0.41+/-0.27 g/day (the majority of emissions are associated with vehicle servicing and disposal). Assuming that the average vehicle travels 10 000 miles per year we estimate that the global warming impact of R-134a leakage from an AC equipped vehicle is approximately 4-5% of that of the CO2 emitted by the vehicle. The results are discussed with respect to the contribution of vehicle emissions to global climate change.

Aerosol Propellants↗
PubMed2002

Sulfate-reducing bacteria colonize pouches formed for ulcerative colitis but not for familial adenomatous polyposis.

PURPOSE: Ileal pouch-anal anastomosis remains the "gold standard" in surgical treatment of ulcerative colitis and familial adenomatous polyposis. Pouchitis occurs mainly in patients with a background of ulcerative colitis, although the reasons for this are unknown. The aim of this study was to characterize differences in pouch bacterial populations between ulcerative colitis and familial adenomatous pouches. METHODS: After ethical approval was obtained, fresh stool samples were collected from patients with ulcerative colitis pouches (n = 10), familial adenomatous polyposis (n = 7) pouches, and ulcerative colitis ileostomies (n = 8). Quantitative measurements of aerobic and anaerobic bacteria were performed. RESULTS: Sulfate-reducing bacteria were isolated from 80 percent (n = 8) of ulcerative colitis pouches. Sulfate-reducing bacteria were absent from familial adenomatous polyposis pouches and also from ulcerative colitis ileostomy effluent. Pouch Lactobacilli, Bifidobacterium, Bacteroides sp, and Clostridium perfringens counts were increased relative to ileostomy counts in patients with ulcerative colitis. Total pouch enterococci and coliform counts were also increased relative to ileostomy levels. There were no significant quantitative or qualitative differences between pouch types when these bacteria were evaluated. CONCLUSIONS: Sulfate-reducing bacteria are exclusive to patients with a background of ulcerative colitis. Not all ulcerative colitis pouches harbor sulfate-reducing bacteria because two ulcerative colitis pouches in this study were free of the latter. They are not present in familial adenomatous polyposis pouches or in ileostomy effluent collected from patients with ulcerative colitis. Total bacterial counts increase in ulcerative colitis pouches after stoma closure. Levels of Lactobacilli, Bifidobacterium, Bacteroides sp, Clostridium perfringens, enterococci, and coliforms were similar in both pouch groups. Because sulfate-reducing bacteria are specific to ulcerative colitis pouches, they may play a role in the pathogenesis of pouchitis.

Adenomatous Polyposis Coli↗
PubMed2001

A comparative study of resident, family, and administrator expectations for service quality in nursing homes.

This article compares the service quality expectations of residents, family, and administrators within a long-term-care context. Expectations for service quality are measured using the SERVQUAL scale. The results support the reliability of the SERVQUAL instrument for nursing home residents. Resident expectations were significantly different from administrators' expectations on all dimensions of quality. The findings are interpreted in terms of expectation formation and the nature of service encounters.

Analysis of Variance↗
PubMed2000

Dating the common ancestor of SIVcpz and HIV-1 group M and the origin of HIV-1 subtypes using a new method to uncover clock-like molecular evolution.

Attempts to estimate the time of origin of human immunodeficiency virus (HIV)-1 by using phylogenetic analysis are seriously flawed because of the unequal evolutionary rates among different viral lineages. Here, we report a new method of molecular clock analysis, called Site Stripping for Clock Detection (SSCD), which allows selection of nucleotide sites evolving at an equal rate in different lineages. The method was validated on a dataset of patients all infected with hepatitis C virus in 1977 by the same donor, and it was able to date exactly the known origin of the infection. Using the same method, we calculated that the origin of HIV-1 group M radiation was in the 1930s. In addition, we show that the coalescence time of the simian ancestor of HIV-1 group M and its closest related cpz strains occurred around the end of the XVII century, a date that could be considered the upper limit to the time of simian-to-human transmission of HIV-1 group M. The results show also that SSCD is an easy-to-use method of general applicability in molecular evolution to calibrate clock-like phylogenetic trees.

Animals↗
PubMed2000

Web-based research: an innovative method for nursing research.

Although still in its infancy, the World Wide Web presents unparalleled opportunities for harnessing the power of the Internet to collect data from populations of interest in an economical and efficient manner. Web-based surveys offer a number of strengths including access to specific populations, speed of data access, and decreased data collection and data entry costs. These advantages are likely to increase as more people begin to use the Web as their primary means of communication. Nurse researchers who embrace this technology will become the pioneers in the new age of nursing research.

Computer User Training↗
PubMed1999

Advances in diagnosis, treatment, and management of orbital and periocular Wegener's granulomatosis.

Ophthalmologists are often in a position to diagnose Wegener's granulomatosis and prevent significant morbidity. The past 2 years have seen advances in diagnosis and management strategies for this condition. Orbital magnetic resonance imaging and histologic profiles have been better characterized. Perhaps the greatest advance has been the recognition of promising therapeutic alternatives to the current standard cytotoxic protocol. Trimethoprim-sulfamethoxazole or methotrexate may be valuable in selected patients with limited forms of Wegener's granulomatosis. Finally, new insights into the mechanisms of disease activation and tissue injury may lead to better treatment and long-term prognosis.

Conjunctival Diseases↗
PubMed1998

Standards for psychological services in long-term care facilities.

Psychologists in Long-Term Care (PLTC), a national network established in 1983, has developed, with input from colleagues and consumers, standards for psychological practice in long-term care facilities. These standards address provider characteristics, methods of referral, assessment practices, treatment, and ethical issues. This article describes the document's development and offers suggestions for its use.

Geriatric Assessment↗
PubMed1997

Postural dynamics and the preferred critical boundary for visually guided reaching.

How do people choose an action to satisfy a goal from among the actions that are afforded by the environment? In 3 experiments the action modes used by actors to reach for a block placed at various distances from them were observed. In each experiment, when actors were not restricted in how they could reach for the object, the transition from their reaching using only arm extension to a mode of reaching in which they used the upper torso to lean forward occurred at closer distances than each actor's absolute critical boundary, beyond which the former action was no longer afforded. In Experiments 2 and 3 actors' seated posture was varied so that the effect of postural dynamics on the distance at which actors actually chose to make the transition between action modes, the preferred critical boundary, could be examined. The results are consistent with the proposal that the preferred critical boundary reflects the relative comfort of available modes of reaching.

Adult↗
PubMed1997

Is a standard regime for anticoagulation with heparin in unstable angina adequate?

AIM: To establish the proportion of patients with unstable angina in whom adequate anticoagulation is achieved using a standard regime of intravenous heparin. METHOD: A prospective series of 108 Emergency Department attendees over a six-month period with a clinical diagnosis of unstable angina for whom anticoagulation with heparin was prescribed were included in the study. The standard regime was a 5000 unit bolus followed by an intravenous infusion of 1000 units per hour (1200 units if the patient's weight was greater than 80 kg), with subsequent adjustments being made by reference to a nomogram. The activated partial thromboplastin time (APTT) was measured at six and 12 hours after treatment began. Two commonly used criteria for adequate heparinisation were compared: 1. APTT greater than 1.5 times control and 2. APTT in the range of 60-85 seconds. RESULTS: There were valid data for 90 patients at six hours and 79 at 12 hours. Compared to the criterion for adequate anticoagulation of APTT greater than 1.5 times the control, 25% of patients were subtherapeutic at six hours and 12% at 12 hours. Compared to the criterion APTT greater than 60 seconds, 53% of patients were subtherapeutic at 6 hours and 47% at 12 hours. At 6 hours, 26% of patients were over-anticoagulated as defined as APTT greater than 85 seconds. This had reduced to 13% by 12 hours. CONCLUSIONS: In the context of recent research suggesting that an APTT of greater than 1.5 times the control is sufficient to reduce complications in unstable angina, our results demonstrate that a standard regime of heparinisation will achieve this goal in the majority of patients within 6 hours of starting heparin therapy. However, if an APTT of 60-85 seconds is the goal, this standard regime is inadequate.

Adult↗
PubMed1997

A university-affiliated community hospital inpatient geriatrics program functioning in an administrative and educational capacity.

OBJECTIVE: To demonstrate an unusual form of inpatient geriatric assessment with unique outcomes. DESIGN: A prospective evaluation of patients admitted to a community hospital-based inpatient geriatrics unit utilizing traditional members of the assessment team along with educational assessment of nurses and satisfaction profiles of patients and/or families. SETTING: A non-profit community hospital in Northeast Washington, DC. PARTICIPANTS: All patients older than age 62 admitted to the 42-bed Geriatric Unit during a 4 1/2 year time period. MEASUREMENTS: Number of total and category recommendations taken by attending physicians from the Inpatient Geriatric Assessment Team, periodic evaluation of unit nurses' geriatric knowledge base and certification, and patient satisfaction through periodic surveys. RESULTS: More than 4500 patients have been evaluated during the past 4 1/2 years. The number of recommendations taken by attending physicians has averaged 31.3 to 50.7% during four consecutive chart reviews involving the first 25 consecutive patients for the month each performed every six months (n = 100). The average age of patients evaluated was 77.2 (minimum of 62 and maximum of 97); 67% were females and 33% males. The average number of recommendations communicated per patient was 4.1, and the average number adhered to 1.6/patient. The overall knowledge base and certification in geriatric nursing has increased significantly over a 2.5-year period. Composite monthly unit patient satisfaction survey scores increased as well. CONCLUSIONS: The program is unique in its development, limitations, and outcomes. Other than the cost of limited geriatric nurse practitioner and faculty salary support, the program has been implemented using only current hospital department personnel. The role of the assessment team is to educate attending nurses and staff physicians. It has not yet been possible to measure objective outcomes. However, the current program also serves the purpose of introducing a new medical program to a community hospital in a nonthreatening way and offers opportunities for research. In addition, the program offers further opportunity for expansion and change.

Aged↗
PubMed1997

Public health nurses' decision making in Canada, Finland, Norway, and the United States.

The purpose of this study was to describe the decision-making processes of 369 public health nurses in Canada, Finland, Norway, and the United States, and to discuss any differences observed among these countries. The results indicate that public health nurses used different decision-making models on the job and that these models varied considerably. Five different decision-making models were identified, each exhibiting features of different decision-making theories. The differences between decision making of public health nurses in different countries were statistically significant. The differences in decision making appear to be due to differences in health care systems in the 4 countries and the nature of the nursing task and context.

Canada↗
PubMed1996

DNA-protein interactions at the telomeric repeats of Schizosaccharomyces pombe.

Gel retardation assays using a probe containing the repeat region of a Schizosaccharomyces pombe chromosomal telomere identified four specific DNA- protein complexes in S. pombe total protein extracts (I, I', IIa and IIb). The proteins responsible for these complexes bound to the telomeric repeat region irrespective of whether or not the repeats were in close proximity to the end of a DNA molecule, and none of them bound strongly to single-stranded DNA. The protein responsible for complex I (TeRF I) was separated from the activity responsible for complexes IIa and IIb (TeRF II) using heparin-Sepharose chromatography. Both factors were efficiently cross-competed by an oligonucleotide containing the 18 bp sequence 5'-GGTTACAGGTTACAGGTT-3', which corresponds to two complete telomeric repeat units. Mutation of the T residues at positions 4 and 11 in the oligonucleotide dramatically reduced binding by TeRF II, but had no affect on binding by TeRF I. The protein responsible for complex I' did not bind strongly to either the wild-type or mutant oligonucleotide.

Base Sequence↗
PubMed1996

Spontaneous metastasis, proliferation characteristics and radiation sensitivity of fractionated irradiation recurrent and unirradiated human xenografts.

PURPOSE: Do tumor cells which survive high dose fractionated irradiation exhibit modified metastasis activity, proliferation kinetics, and/or radiation sensitivity? To address this question experimentally, we have studied three recurrent human tumor xenograft systems. METHODS AND MATERIALS: Three models were derived from a soft tissue sarcoma (HSTS26T), a colon adenocarcinoma (HCT15), and a glioblastoma (HGL21) which had recurred after 90 Gy, 109 Gy, or 77.4 Gy administered in 30 equal doses, respectively. Their production of spontaneous metastasis and cell proliferation characteristics were studied in early generation xenografts in SCID mice, and were compared to those in their previously unirradiated counterparts. As a control, we have also studied each tumor as a post-surgical recurrence. Specimens from the irradiated recurrent and their unirradiated primary tumors were cultured in vitro and their radiation sensitivity determined by clonogenic assay. RESULTS: The three irradiated recurrent tumor systems retained the individual histological features of their unirradiated primary xenografts. A lower metastatic incidence was observed in two of the three irradiated recurrent tumor lines in comparison with their unirradiated control tumors and their surgical recurrent counterparts. No significant differences were found between the irradiated recurrent tumors and their unirradiated counterparts with respect to: volume doubling time, growth time, potential doubling time, mitotic index, PCNA index, and SF2 values. CONCLUSIONS: High dose irradiation given in 30 fractions did not increase the metastatic activity in the three human tumor xenograft systems. Furthermore, the fractionated irradiation did not significantly change their proliferation characteristics and cellular radiation sensitivity.

Adenocarcinoma↗
PubMed1996

The effect of whole-body irradiation of nude mice on the tumor transplantability and control probability of a human soft tissue sarcoma xenograft.

This study has evaluated the impact of the suppression and recovery of the residual immunity in NCr/Sed nude (nu/nu) mice after whole-body irradiation using xenotransplantability and tumor control probability as the end points. For this investigation the xenograft was a human soft tissue sarcoma (HSTS26T). Two assays, the TD50 (the number of tumor cells required to induce a tumor in 50% of the recipients) and the TCD50 (the radiation dose required to control 50% of tumors) were used. For TD50 assays, tumor cells were injected subcutaneously (sc) into the legs of control and whole-body- irradiated nude mice at 1 day or 4, 8 or 12 weeks after irradiation. For TCD50 assays, tumors were transplanted sc into the legs of nude mice which had not been irradiated or which had been given whole-body irradiation at 1 day or 12 weeks prior to transplantation. The tumors were given single-dose irradiation when they reached 6 mm mean diameter under clamp-hypoxic conditions. The results show that the TD50's of mice receiving the injection 1 day and 4 and 8 weeks after whole-body irradiation were 3.6 to >100 times lower than that of unirradiated mice. Two groups which showed a statistically significant difference in TD50 's were those which received the injection 1 day and 8 weeks after whole-body irradiation (P < 0.01 and P < 0.05, respectively). No difference was found in TD50 values between mice that received injection 12 weeks after whole-body irradiation and those which were not irradiated. The TCD50 values of tumors in nonirradiated mice and in mice which had received whole-body irradiation 1 day and 12 weeks prior to to transplantation were 26.8, 44.1 and 33.9 Gy, respectively. Significantly lower TCD50 values were found in groups of nonirradiated mice or mice which received whole-body irradiation 12 weeks prior to transplantation in comparison with the group of mice that received whole-body irradiation on day 1 (both P < 0.05). No significant difference was found between the TCD50 values of the group of mice that received whole-body irradiation 12 weeks prior to transplantation and those for nonirradiated controls. Our conclusion is that the whole-body irradiation can enhance the transplantability of the HSTS26T tumor in nude mice significantly; this enhancing effect will decrease to the pre-irradiation level by 12 weeks after whole-body irradiation. Also, the suppression and recovery of residual immunity after whole-body irradiation can influence the TCD50 values of the same tumor xenografts in nude mice significantly. The changes in TD50 and TCD50 values correlate with the depletion and recovery of the total splenic lymphoid cell number, and especially in natural killer cell activity. We recommend that further immunosuppression in nude mice is necessary when using this model system for studies of human tumors.

Animals↗