Search PubMed⌕ Search

Biomedical subjects

J J Collins

Publications and source records attributed to J J Collins.

At least 127 records · Page 7Linked to original sources
PubMed1994

Communication to workers of epidemiology study results: an industry approach.

Communication to workers of epidemiology study results is gaining increasing emphasis because of the need to notify study subjects and the responsibility to warn workers of potential workplace hazards. Industry has a unique responsibility in this regard both for ethical reasons and for gains in improving workers' knowledge of workplace hazards. We describe our recent efforts to notify 9648 workers potentially interested in the results of an epidemiology study that found increased rates for cancer. We found that both study and nonstudy subjects were equally interested the findings. We conclude that most workers view the notification as evidence of the company's commitment to maintain a safe workplace, and are pleased that the company undertook the study and reported the results to them. Unfavorable comments comprised less than 1% of the responses.

Accidents, Occupational↗
PubMed1994

Management of mild aortic stenosis during coronary artery bypass graft surgery.

A small proportion of patients with significant coronary artery disease referred for coronary artery bypass graft (CABG) surgery have coexistent congenital or valvular disease that, if isolated, would be inadequately severe to justify surgery. While there is general agreement that CABG should be performed for obstruction of major epicardial arteries even without ischemic symptoms in patients having aortic valve replacement (AVR) for aortic stenosis (AS), there has been little or no consideration of whether "mild-to-moderate" AS should be treated by valve repair or AVR at the time of CABG. Between 1975 and 1992, we performed AVR for symptoms or signs of severe AS without significant ischemia on 44 patients with previous CABG. None of these patients were considered to have serious AS at the time of CABG surgery 8 to 164 months (68 months) previously. At aortic surgery, ages ranged from 52 to 83 years (73); 38% were female. In 20 patients with available data, transvalvular gradients ranged from 0 to 23 (12) mmHg at CABG and 29 to 95 (62) mmHg at AVR. Aortic valve areas at CABG ranged from 0.9 to 2.2 (1.5) cm2 and at AVR ranged from 0.3 to 1.7 (0.7) cm2. Appearance of symptoms and signs of severe AS occurred in 16% by 3 years; 45% by 4 years; and 75% by 5 years after CABG surgery. These data observations suggest that mild, asymptomatic valve deformity may progress to symptomatic, hemodynamically severe AS within a short time after CABG surgery, well before recurrent symptoms of coronary obstructive disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Two-day therapy with cefuroxime axetil is effective for urinary tract infections in children.

Short-course therapy for pediatric urinary tract infection (UTI) remains controversial. The present study was undertaken to compare the effectiveness of cefuroxime axetil (Ceftin) as short-course (2-day) versus conventional (10-day) therapy for uncomplicated pediatric UTIs. In a randomized, controlled, prospective study, we enrolled 50 children, 2-11 years of age, to receive oral cefuroxime axetil, 125 mg twice a day, for either 2 or 10 days. UTI was defined as at least 10(5) colonies/ml of a single pathogen isolated on clean catch, or at least 10(4) colonies/ml on a catheterized specimen. A 10-fold or greater reduction in colony count of the initially isolated organism (3-5) days after stopping therapy was considered a bacteriologic success, as long as the absolute colony count was below the threshold for UTI described above. Patients were followed for 15 months with multiple repeat urine cultures and radiologic studies. Twenty-five of the 50 patients enrolled were withdrawn, including 12 for initially inadequate colony counts. Eight of 12 patients in the short-course group (67%), versus 12 of 14 in the conventional-therapy group (86%), were initial bacteriological successes, a nonsignificant difference. All 37 initially isolated uropathogens were sensitive to cefuroxime axetil in vitro. Cefuroxime axetil is an effective antimicrobial for uncomplicated pediatric UTIs. Two-day therapy with cefuroxime axetil appears to be as effective as 10-day therapy, although sample size was limited in this study.

Administration, Oral↗
PubMed1994

Aortic valve endocarditis. Determinants of early survival and late morbidity.

BACKGROUND: Aortic valve surgery for endocarditis remains a high-risk procedure. The objective of this study was to analyze the interaction between the various subsets of endocarditis (native, prosthetic, healed, and active), timing of surgery, and their influence on early and late outcomes. METHODS AND RESULTS: During a 20-year period starting January 1972, 200 patients underwent aortic valve replacement for infective endocarditis (age range, 13 to 88 years; median, 53 years). There were 51 (26%) females, and 109 (55%) were in New York Heart Association functional class IV before surgery. Native valve endocarditis (NVE) and prosthetic valve endocarditis (PVE) were present in 132 (66%) and 68 (34%) patients, respectively. Surgery was required in 120 (60%) during the active phase (AE) and 80 (40%) during the healed phase (HE) of endocarditis. The main indication for surgery in the healed group was progressive congestive heart failure. The indications for the active group were congestive heart failure (68%), continuing active sepsis (70%), echocardiographic vegetation (28%), peripheral emboli (30%), and arrhythmias (13%). Streptococcal infections predominated in NVE, staphylococcal in PVE and AE; culture-negative endocarditis predominated in the healed group. Isolated aortic valve surgery was performed in 68% of the patients, and concomitant procedures (32%) included mitral valve and coronary bypass procedures. The overall operative mortality (OM) was 12.5%. The OM was 7.5% and 22% for NVE and PVE, respectively (P = .004), and 7% for HE versus 15% for AE (P = .06). The OM for early PVE was 33% versus 18% for late PVE (P < .05). Multivariate logistic regression analysis identified PVE and New York Heart Association functional class IV to be independent predictors for early death. Recurrent endocarditis occurred 26 times in 24 patients (11 early, 13 late), with three operative deaths in the early group, all due to residual staphylococcal infections. Freedom from recurrent endocarditis was significantly different between HE (96 +/- 3% and 86 +/- 6% at 5 and 10 years, respectively) and AE (89 +/- 3% and 83 +/- 4%, respectively (P = .02). Long-term survival for discharged patients was 81 +/- 3% and 63 +/- 5% at 5 and 10 years, respectively, with no significant difference between NVE, PVE, AE, and HE. CONCLUSIONS: These data suggest that for active endocarditis, surgery should be delayed to achieve a healed status provided there is no pressing need for immediate surgery. Patients with staphylococcal endocarditis, particularly on a prosthesis, should be operated on sooner and should be covered with antibiotics for an extended period to prevent recurrent PVE. This study stresses the need for aggressive antibiotic prophylaxis, particularly in the presence of a prosthesis.

Aortic Valve↗
PubMed1994

Rapid noninvasive diagnosis and surgical repair of acute ascending aortic dissection. Improved survival with less angiography.

Angiography has been considered the gold standard for the diagnosis of acute dissection of the ascending aorta, but it may increase mortality by imposing an unnecessary delay before surgical repair. In addition, coronary angiography has often been considered essential as well. From 1988 to 1993, 37 patients (median age 61 years, 30 men and 7 women) had acute dissection of the ascending aorta. All of the initial 15 patients (group I) had angiography, even through the diagnosis of aortic dissection had already been made noninvasively in 14; six (40%) of 15 died, three of aortic rupture and none of complications of coronary artery disease. Among the next 22 patients (group II), 21 had a noninvasive diagnosis of acute dissection of the ascending aorta (eight by echocardiography; 13 by computed tomography), and 19 (86%) were operated on without angiography; two died (9%, p = 0.03 versus group I) and neither death was due to aortic rupture or coronary artery disease. Overall, either root or selective coronary angiography was attempted in 18 of 37 patients, but it documented coronary artery disease in only two patients (11%). Coronary artery disease was found in four other patents at autopsy; three of them, including two that died of aortic rupture, had angiography that failed to reveal the coronary artery disease. Noninvasive diagnosis of acute dissection of the ascending aorta is reliable and avoids the risks and delays inherent in invasive angiography. Rapid noninvasive diagnosis of aortic dissection and avoidance of routine angiography appear to improve survival by expediting surgical intervention and thus decreasing the risk of aortic rupture.

Acute Disease↗
PubMed1994

The long-term results of mitral valve reconstruction for the "floppy" valve.

The myxomatous degenerated, prolapsed, or floppy mitral valve is the most common etiology of mitral regurgitation in North American populations. We performed mitral valve reconstruction for this diagnosis in 252 patients from 1984 to 1993. There were 165 males and 87 females ranging in age from 23 to 84 years (mean 64 years); 93 (37%) were > or = 70 years. One hundred eighty-six were New York Heart Association Functional Class III or IV and 29% (72) underwent concomitant coronary bypass operation. Operations included posterior leaflet resection, anterior leaflet resection treatment of chordal pathology by shortening or Gore-Tex replacement, and ring annuloplasty. There were five operative deaths for an operative mortality of 2%. The operative risk in patients under 70 years was 1 of 159 (0.6%) and 4 of 93 (4%) in patients older than 70 years. Ninety percent of patients are asymptomatic in a follow-up period extending 10 years, while structural valve degeneration requiring reoperation at 5 years was 85%. From 1990 to 1993 there has been a less than 5% absolute incidence of structural valve degeneration. Mitral valve reconstruction for complicated floppy mitral valve is feasible and offers excellent early and medium-term results.

Adult↗
PubMed1994

Long-term results of mitral valve reconstruction for regurgitation of the myxomatous mitral valve.

The myxomatous, degenerated, prolapsed or "floppy" mitral valve is the most common cause of mitral regurgitation in North America. Mitral valve reconstruction for mitral regurgitation was carried out in 219 consecutive patients with a myxomatous mitral valve from 1984 to 1993. Of the 139 men and 80 women, 23 to 84 years of age (mean 63 years), 36% of patients were 70 years of age or older, 77% were in New York Heart Association functional class III or IV, and 29% had coronary artery disease necessitating coronary bypass. The most common operation was posterior leaflet resection (161 patients [73%]). The anterior leaflet was resected in 14 patients, and both the anterior and posterior leaflets were resected in 15 patients. A variety of other techniques were used, including commissuroplasty and use of annuloplasty rings. A flexible Duran ring was used in 111 patients (51%), a Carpentier-Edwards ring in 44 patients (20%), and no ring was used in 64 patients (29%). Five operative deaths occurred (2.3%); four of the five deaths occurred in patients 70 years of age or older (5.1%); and one in 141 patients (0.7%) was younger than 70 years of age. In the late postoperative period (mean follow-up 2 years), 90% of patients had no symptoms, two had endocarditis, and seven patients had thromboemboli (transient in four, permanent in three). Structural valve degeneration requiring reoperation occurred late in 12 patients; eight were in posterior leaflet resection and two in anterior or anterior and posterior; six of 12 had no annuloplasty ring. The incidence of structural valve degeneration was less than 5% from 1990 to 1993. No systolic anterior motion of the mitral valve was seen with postoperative echocardiography before discharge. Actuarial analysis at 5 years for overall survival was 86% +/- 5%, freedom from infectious valve degeneration 97% +/- 2%, and freedom from thromboembolism 94% +/- 3%. Freedom from structural valve degeneration overall was 83% +/- 4%, with a flexible ring it was 89% +/- 6%, with a rigid ring it was 88% +/- 6%, and with no ring it was 67% +/- 12% (p = 0.03). Mitral valve reconstruction for complicated myxomatous disease of the mitral valve, regardless of leaflet involvement, is feasible and offers excellent early and late results.

Actuarial Analysis↗
PubMed1993

Dioxin exposure.

Explore the source record for details and available documents.

Carcinogens, Environmental↗
PubMed1993

Perspective on the content of worker notifications.

The concept of worker notification has evolved over the years to a prevailing view that workers should be notified of all epidemiologic studies that make use of their medical information. To adequately communicate health information to workers, epidemiologists must consider the intended audience along with its need for risk information that is scientifically valid and clearly outlines areas of uncertainty. This goal is facilitated by full disclosure to workers of information pertinent to the planning, conduct, and interpretation of research efforts. Subjectivity in choosing unanticipated research findings for inclusion in worker notifications may permit bias toward a personal viewpoint, but this can be minimized by prestudy agreement on appropriate criteria for selecting which research findings to communicate. Epidemiologic theory and principles of causal inference should guide the development of appropriate criteria. The timeliness of worker communications has received limited attention, and workers have often been the "last to know" about important studies. This may influence workers' receptivity to the risk message. Sponsoring organizations should ensure that an acceptable communications plan is included in research protocols and that the plan accords priority to notifying workers about study results.

Causality↗
PubMed1993

Open-loop and closed-loop control of posture: a random-walk analysis of center-of-pressure trajectories.

A new conceptual and theoretical framework for studying the human postural control system is introduced. Mathematical techniques from statistical mechanics are developed and applied to the analysis and interpretation of stabilograms. This work was based on the assumption that the act of maintaining an erect posture could be viewed, in part, as a stochastic process. Twenty-five healthy young subjects were studied under quite-standing conditions. Center-of-pressure (COP) trajectories were analyzed as one-dimensional and two-dimensional random walks. This novel approach led to the extraction of repeatable, physiologically meaningful parameters from stabilograms. It is shown that although individual stabilograms for a single subject were highly variable and random in appearance, a consistent, subject-specific pattern emerged with the generation of averaged stabilogram-diffusion plots (mean square COP displacement vs time interval). In addition, significant inter-subject differences were found in the calculated results. This suggests that the steady-state behavior of the control mechanisms involved in maintaining erect posture can be quite variable even amongst a population of age-matched, anthropometrically similar, healthy individuals. These posturographic analyses also demonstrated that COP trajectories could be modelled as fractional Brownian motion and that at least two control systems-a short-term mechanism and a long-term mechanism-were operating during quit standing. More specifically, the present results suggest that over short-term intervals open-loop control schemes are utilized by the postural control system, whereas over long-term intervals closed-loop control mechanisms are called into play. This work strongly supports the position that much can be learned about the functional organization of the postural control system by studying the steady-state behavior of the human body during periods of undisturbed stance.

Adult↗
PubMed1993

Decrease in operative risk of reoperative valve surgery.

We analyzed the risk of valve re-replacement in 640 patients reoperated on between 1980 and 1992. This represented 17% of total valve operations (640/3,764) during that period. A univariate and logistic multivariate analysis was carried out for four sequential periods for the 640 re-replacement patients to determine if changing methods of perfusion and myocardial protection affected recent results. There were 323 female and 317 male patients with a mean age of 58 years (range, 17 to 84 years). Ninety-seven (15%) had coronary artery bypass grafting, 135 (21%) were 70 years old or older, 377 (59%) were in New York Heart Association functional class III or less, and 263 (41%) were in functional class IV. The aortic valve was re-replaced in 245, the mitral valve in 289, and both aortic and mitral synchronously in 106. Four periods were analyzed: 1980 through 1982, 1983 through 1985, 1986 through 1988, and 1989 through 1992. The overall operative mortality was 65 of 640 patients (10%), falling from 12/73 (16%) in 1980 through 1982 to 23/268 (8%) in 1989 through 1992 (p = 0.05). Univariate and multivariate logistic analysis documented that New York Heart Association functional class was highly significant for operative mortality; operative mortality was 4% for functional classes I through III, and 19% for functional class IV (p < or = 0.001). The requirement for coronary bypass was of borderline significance (p = 0.05), and year of operation was also significant. Mortality for re-replacement of aortic valve fell from 15% to 10%, double valve from 20% to 9%, and mitral valve from 16% to 6%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

The mortality experience of workers exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin in a trichlorophenol process accident.

Epidemiologic studies on dioxin, specifically 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), have not consistently found an increased cancer risk. This study examines mortality rates for 754 employees at a chemical plant after an accident in 1949 in which 122 workers developed chloracne from high exposure to TCDD. We also examined exposure to 4-aminobiphenyl, a potential bladder carcinogen. Although the numbers are small, and confounding factors cannot be ruled out, workers exposed to 4-aminobiphenyl who developed chloracne from the accident had increased mortality rates from soft tissue sarcoma, bladder cancer, and respiratory cancer. All soft tissue sarcomas occurred among workers with potential 4-aminobiphenyl exposure, whereas no soft tissue sarcomas occurred among workers with TCDD exposure alone. In these workers, exposure to TCDD alone at levels great enough to cause chloracne was not associated with increased cancer rates.

Accidents, Occupational↗
PubMed1993

Aortic valve replacement in the elderly. Effect of gender and coronary artery disease on operative mortality.

BACKGROUND: Aortic valve replacement remains the treatment of choice for aortic valve disease, even in the extreme elderly who may present with advanced symptoms. Defining risk factors for short-term survival was the object of this study. METHODS AND RESULTS: This was a retrospective analysis of 717 patients at least 70 years of age who underwent aortic valve replacement alone or with coronary artery bypass graft between 1980 and 1992. Age range was 70 to 95 years, and mean age was 77 years; there were 529 septuagenarians (74%); 188 were octogenarians (26%); 326 were women (45%); and 386 patients (54%) had aortic valve replacement and coronary artery bypass graft. Atrial fibrillation/flutter or heart block was present in 16%, and 34% of patients were in New York Heart Association (NYHA) functional class IV. Aortic stenosis was present in 88%, and mechanical prostheses were used in 22% of patients. There were 47 deaths, giving an overall operative mortality of 6.6%, with 4.2% for aortic valve replacement and 8.8% for aortic valve replacement and coronary artery bypass graft (P = .01). The operative mortality for aortic valve replacement was 2.9% versus 10.3% for aortic valve replacement and coronary artery bypass graft in women (P = .006). The corresponding values for men were 5.6% and 7.4% (P = .31). Multivariate logistic regression showed coronary artery bypass graft and NYHA class IV to be significant predictors of operative mortality in women. The significant predictors in men were NYHA class IV, atrial fibrillation/flutter or heart block rhythm, and the use of mechanical prosthesis. Age was not a predictor of operative mortality in either sex. CONCLUSIONS: Aortic valve replacement carries an acceptable mortality rate in elderly patients. Female gender was a significant predictor of operative mortality in the concomitant coronary artery bypass graft group; however, gender was not a predictor of operative mortality in the isolated aortic valve replacement group. Advance stage of the disease process represented by NYHA class IV was a significant predictor of mortality for the whole group, stressing the need for earlier referral for surgery.

Aged↗
PubMed1992

Surgical treatment of adult atrial septal defect: early and long-term results.

OBJECTIVES: The purpose of this study is to determine the early and late results of the surgical repair of atrial septal defect in adults. BACKGROUND: Progressively limiting, untreated atrial septal defect can lead to the early death of middle-aged adults. Recently it has been suggested that the closure of atrial septal defects might be accomplished with interventional cardiac techniques. Although the long-term results of the transcatheter closure are as yet unknown, the outcome of surgical therapy has been shown to be beneficial for almost 40 years. METHODS: Between 1971 and 1991, 166 consecutive patients underwent surgical repair of a secundum or sinus venosus atrial septal defect, or both, at the Brigham and Women's Hospital, Boston. There were 120 women and 46 men in this group; the mean age was 44 years and 58 (35%) of the patients were > or = 50 years old. The average pulmonary to systemic flow ratio was 3.0, and 57 patients had a peak systolic pulmonary artery pressure > 30 mm Hg. RESULTS: There were two operative deaths (early mortality rate 1.2%), and 13% of the patients had a perioperative complication. One hundred fifty-three of the 164 survivors were followed up for a mean of 90 months (range 2 to 247). There were eight late deaths (late mortality rate 4.9%) and a late morbidity rate of 12.4% (in most cases due to arrhythmias). The 5- and 10-year survival rates are 98% and 94%, respectively, and the probability of event-free survival (with no morbidity or mortality) at 5 years is 97% and at 10 years is 92%. CONCLUSIONS: The results indicate that the surgical correction of atrial septal defect in adults is safe and efficacious as confirmed by 20 years of follow-up.

Adult↗