Search PubMed⌕ Search

Biomedical subjects

T J Ryan

Publications and source records attributed to T J Ryan.

At least 37 records · Page 2Linked to original sources
PubMed2001

Survey of the Asp f 1 allergen in office environments.

Sick Building Syndrome remains a prevalent problem with patient complaints similar to typical allergy symptoms. Unlike household allergens typically found in domestic reservoirs, the allergen from a common fungus like Aspergillus fumigatus (i.e., Asp f 1) is conceivably widespread in the work environment. This project surveyed airborne levels of the Asp f 1 allergen in office and non-industrial occupational environments, as well as the dust reservoirs of A. fumigatus believed to be responsible for those levels. Airborne and bulk dust samples were collected, extracted, and assayed for Asp f 1. Concurrently, bulk dusts collected from the same locations were selectively cultured for A. fumigatus, and mesophilic fungi and bacteria. Samples were collected during both wet and dry climatological conditions from paired wet and dry building locations to examine the possibility of Asp f 1 increases due to fungal growth blooms. Very low levels of Asp f 1 were detected but only in the airborne samples (2/120 positive samples, with 3.6 ng/m3 and 1.8 ng/m3; LOD < 1.2 ng/m3). No dust samples showed even detectable traces of the allergen (LOD = 5 ng/g dust). Although A. fumigatus counts from dusts fluctuated significantly with exterior moisture events, analysis of wet versus dry period samples showed no differences in Asp f 1 levels. These results indicate that even in the presence of measurable fungal concentrations, background levels of Asp f 1 are low. Nonindustrial office buildings devoid of indoor air quality issues were not observed to have significant levels of the Asp f 1 allergen in the geographical region studied.

Air Pollutants, Occupational↗
PubMed2001

Health for all.

Explore the source record for details and available documents.

Attitude of Health Personnel↗
PubMed2001

Impact of underuse, overuse, and discretionary use on geographic variation in the use of coronary angiography after acute myocardial infarction.

BACKGROUND: Geographic variation in the use of medical procedures has been well documented. However, it is not known whether this variation is due to differences in use when procedures are indicated, discretionary, or contraindicated. OBJECTIVES: To examine whether use of coronary angiography after acute myocardial infarction (AMI) according to appropriateness criteria varied across geographic regions and whether underuse, overuse, or discretionary use accounted for variation in overall use. DESIGN: Retrospective cohort study using data from the Cooperative Cardiovascular Project. SETTING: Ninety-five hospital referral regions. PATIENTS: There were 44,294 Medicare patients hospitalized with AMI during 1994 or 1995, classified according to appropriateness for angiography. MAIN OUTCOME MEASURE: Variation in use of angiography, as measured by the difference between high and low rates of use across regions. RESULTS: Across regions, variation in the use of angiography was similar for indications judged necessary; appropriate, but not necessary; or uncertain. Variation was lowest for indications judged unsuitable (difference between high rate and low rate across regions = 16.3%; 95% CI = 12.6%; 20.6%). The primary cause of variation in the overall rate of angiography was due to use for indications judged appropriate, but not necessary or uncertain. When variation associated with these indications was accounted for, the difference between the resulting high and low overall rates was 10.8% (9.4%, 12.4%). In contrast, variation in the overall rate remained high when underuse in necessary situations or overuse in unsuitable situations was accounted for. CONCLUSIONS: Across regions, practice was more similar for patients categorized unsuitable for angiography than for patients with other indications. Variation in overall use of angiography appeared to be driven by utilization for discretionary indications rather than by underuse or overuse. If equivalent rates across geographic areas are judged desirable, then greater effort must be directed toward defining care for patients with discretionary indications.

Aged↗
PubMed2000

Relation between operator and hospital volume and outcomes following percutaneous coronary interventions in the era of the coronary stent.

CONTEXT: Studies have found an association between physician and institution procedure volume for percutaneous coronary interventions (PCIs) and patient outcomes, but whether implementation of coronary stents has allowed low-volume physicians and centers to achieve outcomes similar to their high-volume counterparts is unknown. OBJECTIVE: To assess the relationship between physician and hospital PCI volumes and patient outcomes following PCIs, given the availability of coronary stents. DESIGN, SETTING, AND PARTICIPANTS: Analysis of data from Medicare National Claims History files for 167 208 patients aged 65 to 99 years who had PCIs performed by 6534 physicians at 1003 hospitals during 1997. Of these procedures, 57.7% involved coronary stents. MAIN OUTCOME MEASURES: Rates of coronary artery bypass graft (CABG) surgery and 30-day mortality occurring during the index episode of care, stratified by physician and hospital PCI volume. RESULTS: Overall unadjusted rates of CABG during the index hospitalization and 30-day mortality were 1.87% and 3.30%, respectively. After adjustment for case mix, patients treated by low-volume (<30 Medicare procedures) physicians had an increased risk of CABG vs patients treated by high-volume (>60 Medicare procedures) physicians (2.25% vs 1.55%; P<.001), but there was no difference in 30-day mortality rates (3.25% vs 3.39%; P =.27). Patients treated at low-volume (<80 Medicare procedures) centers had an increased risk of 30-day mortality vs patients treated at high-volume (>160 Medicare procedures) centers (4.29% vs 3.15%; P<. 001), but there was no difference in the risk of CABG (1.83% vs 1. 83%; P =.96). In patients who received coronary stents, the CABG rate was 1.20% vs 2.78% for patients not receiving stents, and the 30-day mortality rate was 2.83% vs 3.94%. Among patients who received stents, those treated at low-volume centers had an increased risk of 30-day mortality vs those treated at high-volume centers, whereas those treated by low-volume physicians had an increased risk of CABG vs those treated by high-volume physicians. CONCLUSION: In the era of coronary stents, Medicare patients treated by high-volume physicians and at high-volume centers experience better outcomes following PCIs.

Aged↗
PubMed2000

Molecular modeling and site-directed mutagenesis define the catalytic motif in human gamma -glutamyl hydrolase.

Human gamma-glutamyl hydrolase (hGH) is a central enzyme in folyl and antifolylpoly-gamma-glutamate metabolism, which functions by catalyzing the cleavage of the gamma-glutamyl chain of substrates. We previously reported that Cys-110 is essential for activity. Using the sequence of hGH as a query, alignment searches of protein data bases were made using the SSearch and TPROBE programs. Significant similarity was found between hGH and the glutamine amidotransferase type I domain of Escherichia coli carbamoyl phosphate synthetase. The resulting hypothesis is that the catalytic fold of hGH is similar to the folding of this domain in carbamoyl phosphate synthetase. This model predicts that Cys-110 of hGH is the active site nucleophile and forms a catalytic triad with residues His-220 and Glu-222. The hGH mutants C110A, H220A, and E222A were prepared. Consistent with the model, mutants C110A and H220A were inactive. However, the V(max) of the E222A hGH mutant was reduced only 6-fold relative to the wild-type enzyme. The model also predicted that His-171 in hGH may be involved in substrate binding. The H171N hGH mutant was found to have a 250-fold reduced V(max). These studies to determine the catalytic mechanism begin to define the three dimensional interactions of hGH with poly-gamma-glutamate substrates.

Amino Acid Motifs↗
PubMed2000

Appropriateness of coronary angiography after myocardial infarction among Medicare beneficiaries. Managed care versus fee for service.

BACKGROUND: Previous studies have documented that cardiac procedures are performed less frequently in patients enrolled in managed-care plans than in those with fee-for-service coverage. However, it is not known whether this difference is due to less frequent use of cardiac procedures when they are indicated or to less frequent use when they are not indicated. METHODS: We compared the use of coronary angiography after acute myocardial infarction among Medicare beneficiaries who had traditional fee-for-service coverage with the use among Medicare beneficiaries enrolled in managed-care plans. The analysis was adjusted for differences in demographic and clinical characteristics of the patients and for characteristics of the hospitals to which they were admitted. We studied more than 50,000 beneficiaries in seven states and evaluated their care according to guidelines proposed by the American College of Cardiology and the American Heart Association (ACC-AHA). RESULTS: Among the 44 percent of patients in both groups who had ACC-AHA class I indications (those for which angiography is useful and effective), more fee-for-service beneficiaries than managed-care enrollees underwent angiography (46 percent vs. 37 percent, P<0.001). The rate of angiography was very low among patients with class I indications who were admitted to hospitals without angiography facilities (31 percent in the fee-for-service group and 15 percent in the managed-care group, P<0.001). Among patients with class III indications (those for which angiography is not effective), the rate of use was low in both groups (approximately 13 percent). CONCLUSIONS: In situations in which angiography is thought to be useful, it is used less often among Medicare beneficiaries enrolled in managed-care plans than among those with fee-for-service coverage. Moreover, rates of use among patients with class I indications are fairly low in both groups, suggesting that there is room for improving the care of elderly patients with myocardial infarction, especially those admitted to hospitals without angiography facilities.

Aged↗
PubMed2000

Safety and efficacy of percutaneous coronary interventions performed immediately after diagnostic catheterization in northern new england and comparison with similar procedures performed later.

"Ad hoc" percutaneous coronary interventions (PCIs)-those performed immediately after diagnostic catheterization-have been reported in earlier studies to be safe with a suggestion of higher risk in certain subgroups. Despite increasing use of this strategy, no data are available in recent years with new device technology. We studied use of an ad hoc strategy in a large regional population to determine its use and outcomes compared with staged procedures. A database from the 6 centers performing PCIs in northern New England and 1 center in Massachusetts was analyzed. During 1997, excluding only patients requiring emergency procedures or those with a prior PCI, 4,136 PCIs were performed, 1,748 (42.3%) of these being ad hoc procedures. Patients having ad hoc procedures were less likely to have peripheral vascular disease, renal failure, prior myocardial infarction, or coronary artery bypass surgery, congestive heart failure, or poor left ventricular function, and more likely to have received preprocedural intravenous heparin or nitroglycerin or to have required an urgent procedure. Narrowings treated during ad hoc procedures were less frequently types B and C or in saphenous vein grafts. Adjusted rates of clinical success were not different between ad hoc and non-ad hoc procedures (93.7% vs 93.6%); there was no difference in the incidence of death (0.6% vs 0.5%), emergency (0. 9% vs 0.8%) or any (1.4% vs 0.8%) coronary artery bypass surgery, or myocardial infarction (2.6% vs 2.0%). As currently practiced in our region, ad hoc intervention is used selectively with outcomes similar for ad hoc and non-ad hoc procedures.

Angina Pectoris↗
PubMed2000

Quality of life after coronary revascularization in the United States and Canada.

Cardiac procedures are performed less frequently in Canada than in the United States (US), yet rates of cardiac death and myocardial infarction are similar. We therefore sought to compare long-term symptoms and quality of life in Canadian and American patients undergoing initial coronary revascularization. The 161 patients enrolled in the Bypass Angioplasty Revascularization Investigation at the Montreal Heart Institute were compared with 934 patients enrolled at 7 US sites. Patients' outcomes were documented for 5 years after random assignment to percutaneous transluminal coronary angioplasty or coronary artery bypass graft surgery. Functional status was assessed using the Duke Activity Status Index. Canadian patients were significantly younger and had more angina at study entry. Death and nonfatal myocardial infarction were not significantly different between Canadian and US patients after adjustment for baseline risk. Canadian patients had significantly greater improvements in functional status at 1-year follow-up (Duke Activity Status Index score + 13.5 vs. + 6.0, p = 0.002), but this difference progressively narrowed over 5 years. Angina was equally prevalent in Canadian and US patients at 1 year (16% vs. 19%), but significantly more prevalent in Canadian patients at 5 years (36% vs. 16%, p = 0.001). Repeat revascularization procedures were performed less often over 5 years among Canadian patients (26% vs. 34%, p = 0.08), especially coronary artery bypass graft surgery after initial percutaneous transluminal coronary angioplasty (18% vs. 32%, p = 0.03). These results suggest more anginal symptoms are required in Canada before coronary revascularization, but as a result Canadians receive greater improvements in quality of life after the procedure.

Angina Pectoris↗
PubMed2000

Ultrastructure of the reproductive system of the black swamp snake (Seminatrix pygaea). II. Annual oviducal cycle.

This article is the first ultrastructural study on the annual oviducal cycle in a snake. The ultrastructure of the oviduct was studied in 21 females of the viviparous natricine snake Seminatrix pygaea. Specimens were collected and sacrificed in March, May, June, July, and October from one locale in South Carolina during 1998-1999. The sample included individuals: 1) in an inactive reproductive condition, 2) mated but prior to ovulation, and 3) from early and late periods of gravidity. The oviduct possesses four distinct regions from cranial to caudal: the anterior infundibulum, the posterior infundibulum containing sperm storage tubules (SSTs), the uterus, and the vagina. The epithelium is simple throughout the oviduct and invaginations of the lining form tubular glands in all regions except the anterior infundibulum and the posterior vagina. The tubular glands are not alveolar, as reported in some other snakes, and simply represent a continuation of the oviducal lining with no additional specializations. The anterior infundibulum and vagina show the least amount of variation in relation to season or reproductive condition. In these regions, the epithelium is irregular, varying from squamous to columnar, and cells with elongate cilia alternate with secretory cells. The secretory product of the infundibulum consists largely of lipids, whereas a glycoprotein predominates in the vagina; however, both products are found in these regions and elsewhere in the oviduct. In the SST area and the anterior vagina, tubular glands are compound as well as simple. The epithelium of the SST is most active after mating, and glycoprotein vacuoles and lipid droplets are equally abundant. When present, sperm form tangled masses in the oviducal lumen and glands of the SST area. The glands of the uterus are always simple. During sperm migration, a carrier matrix composed of sloughed epithelial cells, a glycoprotein colloid, lipids, and membranous structures surround sperm in the posterior uterus. During gravidity, tubular glands, cilia, and secretory products diminish with increasing development of the fetus, and numerous capillaries abut the basal lamina of the attenuated epithelial lining of the uterus.

Animals↗
PubMed2000

Predictors of mortality for patients undergoing cardiac valve replacements in New York State.

BACKGROUND: The objective of this study was to identify the mortality rates and significant independent risk factors for mortality for each of six valve replacement groups. METHODS: A total of 14,190 patients who underwent valve replacement in New York State from 1995 to 1997 were classified into six major groups and significant independent risk factors for inpatient mortality were identified for each of the groups using stepwise logistic regression. RESULTS: Mortality rates ranged from 3.33% for isolated aortic valve surgical procedures to 18.72% for multiple valve replacements with coronary artery bypass graft operations. The number of years in excess of age 55 was a significant multivariate predictor of mortality for all six groups of patients. Shock was a significant predictor for five of the six groups, and in each of those groups it was the risk factor with the highest odds ratio. CONCLUSIONS: Significant patient risk factors are relatively consistent across different types of valve replacement procedures. The probability of survival from valve surgical procedures is highly dependent on the patient's preoperative profile and the type of valve operation.

Aged↗
PubMed2000

Glutamyl hydrolase. pharmacological role and enzymatic characterization.

gamma-Glutamyl hydrolase (GH, EC 3.4.19.9) is a lysosomal and secreted glycoprotein that hydrolyzes the gamma-glutamyl tail of antifolate and folate polyglutamates. Tumor cells that have high levels of GH are inherently resistant to classical antifolates, and further resistance can be acquired by elevations in GH following exposure to this class of antitumor agents. The highest level of expression in normal tissues occurs in the liver and kidney in humans. When panels of tumors are compared with normal tissues, GH expression is elevated in cancerous hepatic and breast tissue. A second poly-gamma-glutamate hydrolyzing enzyme, glutamate carboxypeptidase II, is a transmembrane protein whose active site is on the outside of the cell, occurring in the prostate gland, small intestine, brain, kidney, and tumor neovasculature. It is a high-affinity (nanomolar), low-turnover, zinc co-catalytic enzyme. In contrast, GH is a low-affinity (micromolar), high-turnover enzyme that has a cysteine at the active site. Data are presented suggesting that Cys110 is the nucleophile that attacks the gamma-amide linkage and causes hydrolysis. GH is being evaluated as an intracellular target for inhibition in order to enhance the therapeutic activity of antifolates and fluorouracil.

Animals↗
PubMed2000

Dermatology in the developing world. Needs and solutions.

Dermatologists, who have assets far in excess of most of the people of the world, have the opportunity to contribute globally to the forces of social progress. This article addresses the dermatologic needs of the developing world and discusses how the needs of these areas, including rural areas in the United States, should be addressed.

Dermatology↗
PubMed2000

A comparison of short- and long-term outcomes for balloon angioplasty and coronary stent placement.

OBJECTIVES: We sought to compare patient outcomes for coronary stent placement and balloon angioplasty. BACKGROUND: Since 1994, the number of patients treated only with balloon angioplasty has decreased nationally, whereas the use of coronary stents as an alternative has grown tremendously. The objectives of this study were to compare short- and long-term survival and subsequent revascularization rates for patients undergoing single-vessel balloon angioplasty and coronary stent placement. METHODS: New York's Coronary Angioplasty Registry was used to identify New York patients undergoing either balloon angioplasty or stent placement between July 1, 1994, and December 31, 1996. Statistical models were used to compare risk-adjusted short- and long-term survival and subsequent coronary artery bypass graft surgery (CABG) and percutaneous coronary interventions (PCIs). RESULTS: No significant differences were found in adjusted in-patient mortality, but patients who had balloon angioplasty were, on average, 1.36 times more likely to have died at any time during the two-year period after the index procedure (p = 0.003). The adjusted in-patient CABG rate was significantly higher for balloon angioplasty (2.72% vs. 1.66%, p<0.0001), and the adjusted two-year CABG rate was also significantly higher for balloon angioplasty (10.81% vs. 7.25%, p<0.001). The adjusted two-year rate for subsequent PCIs was also significantly higher for balloon angioplasty (19.6% vs. 14.3%, p<0.0001). Although measures were taken to eliminate or minimize the effect of selection bias, it should be noted that patients with stents were healthier at hospital admission than patients who had balloon angioplasty. CONCLUSIONS: Stent placement is associated with significantly lower risk-adjusted long-term mortality, CABG and subsequent PCI rates, as compared with balloon angioplasty.

Aged↗
PubMed2000

Short- and long-term mortality for patients undergoing primary angioplasty for acute myocardial infarction.

OBJECTIVES: The goal of this study was to learn more about the risk factors and short- and long-term outcomes for primary angioplasty. BACKGROUND: Primary angioplasty (direct angioplasty without antecedent thrombolytic therapy) has been an effective alternative to thrombolytic therapy for patients with acute myocardial infarction (AMI). However, most reported studies have been compromised by small sample sizes and short observation times. METHODS: New York's coronary angioplasty registry was used to identify New York patients undergoing angioplasty within 6 h of AMI between January 1, 1993 and December 31, 1996. Statistical models were used to identify significant risk factors for in-patient and long-term survival and to estimate long-term survival for all patients as well as various subsets of patients undergoing primary angioplasty. RESULTS: The in-hospital mortality rate for all primary angioplasty patients was 5.81%. When patients in preprocedural shock (who had a mortality rate of 45%) were excluded, the in-hospital mortality rate dropped to 2.60%. Mortality rates for all primary angioplasty patients at one year, two years and three years were 9.3%, 11.3% and 12.6%, respectively. Patients treated with stent placement did not have significantly lower risk-adjusted in-patient or two-year mortality rates. CONCLUSIONS: Primary angioplasty is a highly effective option for AMI.

Aged↗
PubMed2000

An evaluation of the gamma interferon test for detecting bovine tuberculosis in cattle 8 to 28 days after tuberculin skin testing.

The gamma interferon (IFN -gamma) test was evaluated for its ability to diagnose bovine tuberculosis in cattle that 8 to 28 days previously had a positive caudal fold skin test. The sensitivity of the test was determined in a group of 163 Mycobacterium bovis -infected cattle from 21 herds. The specificity was estimated in a group of 213 cattle which had reacted to a caudal fold test, but were from 82 herds that had no evidence of infection with M bovis. The sensitivity and specificity of the IFN -gamma test was 85 and 93 per cent respectively. No significant differences in the sensitivity and specificity of the test were observed between blood samples that were cultured on the day of collection and those cultured the day after collection. These findings support the use of the IFN -gamma test as a practical serial test that can be used to complement the caudal fold skin test.

Animals↗
PubMed2000

Larva therapy in wound management.

The use of maggots for wound debridement has a long history and has lately gained ground in several countries. We collected prospective data to examine the current use of larva therapy (LT) in the UK. Quantitative information was collected on 70 patients treated in nine hospitals. LT is used primarily to treat leg ulcers and generally involves three applications of larvae at two to three day intervals. This method is judged effective in wound debridement and promotes the growth of granulation tissue. Wound exudate, odour, infection and pain are all reduced by the treatment. Adverse reactions are infrequent but include pain, bleeding, pyrexia and influenza-like symptoms. Prevention of hospital admission and surgery, reduced need for antibiotics and reduced hospital stay are all identified as outcomes of LT. The nurse practitioners who used LT believed it to have an important role in wound management. A randomized clinical trial, comparing LT with other debriding agents, is required for evaluation of cost effectiveness.

Debridement↗