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Biomedical subjects

C S Ross

Publications and source records attributed to C S Ross.

15 recordsLinked to original sources
PubMed2004

A model for cardiopulmonary bypass redesign.

INTRODUCTION: A portion of patients undergoing cardiac surgery may develop focal and/or subtle brain injuries secondary to cardiac surgery. There is evidence that, in some cases, these injuries may be related to cardiopulmonary bypass (CPB). Embolism and hypoperfusion are the dominant mechanisms for focal neurologic injuries among coronary artery bypass graft (CABG) surgery patients. Recent studies suggest that these mechanisms may also produce the more prevalent subtle neurological deficits. The aim of our current work is to obtain a thorough understanding of the processes of care associated with the production of embolic activity, cerebral hypoperfusion, and hemodynamic aberrations that often occur during CPB. METHODS: We developed a system for simultaneous recording of physiologic parameters, embolic activity in the CPB circuit and in the cerebral arteries, and near infrared regional cerebral oxyhemoglobin saturation (NIRS) during cardiac surgery. All data were synchronized with a video recording of the surgical procedure. Periods of embolic activity and NIRS were subsequently related to surgical and CPB processes of care through a systematic review of the patient's surgical case video. RESULTS: To date, we have enrolled 47 patients undergoing coronary and/or valvular procedures. We have observed wide variation across patients in detected cerebral embolic counts, NIRS and physiologic parameters. We have identified increased embolic counts in the CPB circuit related to specific processes and events such as the method of venous drainage, the entrainment of air in the venous line, the injection of medications into the CPB circuit and blood sampling from the CPB circuit. A portion of detected changes in NIRS were related to periods of hypotension and positioning of the heart during the construction of distal coronary artery grafts on the posterior coronary artery vessels. SUMMARY: Use of this model provides the surgical team with detailed information regarding the contribution of CPB to the creation of precursors of neurological injury. This system provides meaningful data to guide the surgical team in the redesign of the CPB system and associated techniques.

Brain Injuries↗
PubMed2001

Lowest hematocrit on bypass and adverse outcomes associated with coronary artery bypass grafting. Northern New England Cardiovascular Disease Study Group.

BACKGROUND: Cardiac surgery patients' hematocrits frequently fall to low levels during cardiopulmonary bypass. METHODS: We investigated the association between nadir hematocrit and in-hospital mortality and other adverse outcomes in a consecutive series of 6,980 patients undergoing isolated coronary artery bypass graft surgery. The lowest hematocrit during cardiopulmonary bypass was recorded for each patient. Patients were divided into categories based on their lowest hematocrit. Women had a lower hematocrit during bypass than men but both sexes are represented in each category. RESULTS: After adjustment for preoperative differences in patient and disease characteristics, the lowest hematocrit during cardiopulmonary bypass was significantly associated with increased risk of in-hospital mortality, intra- or postoperative placement of an intraaortic balloon pump and return to cardiopulmonary bypass after attempted separation. Smaller patients and those with a lower preoperative hematocrit are at higher risk of having a low hematocrit during cardiopulmonary bypass. CONCLUSIONS: Female patients and patients with smaller body surface area may be more hemodiluted than larger patients. Minimizing intraoperative anemia may result in improved outcomes for this subgroup of patients.

Aged↗
PubMed2000

Mediastinitis and long-term survival after coronary artery bypass graft surgery.

BACKGROUND: Mediastinitis is a dreaded complication of coronary artery bypass surgery (CABG). The long-term effect of mediastinitis on mortality after CABG has not been well studied. METHODS: We examined the survival of 15,406 consecutive patients undergoing isolated CABG surgery from 1992 through 1996. Patient records were linked to the National Death Index. Mediastinitis was defined as occurring during the index admission and requiring reoperation. RESULTS: Mediastinitis occurred in 193 patients (1.25%). Patients with mediastinitis were older and more likely to have had emergency surgery, diabetes, peripheral vascular disease, chronic obstructive pulmonary disease, and preoperative dialysis-dependent renal failure. Patients with mediastinitis were also more likely to be severely obese and had somewhat lower preoperative ejection fraction. After multivariate adjustment for these factors, the first year post-CABG survival rate was 78% with mediastinitis and 95% without, and the hazard ratio for mortality during the entire follow-up period was 3.09 (CI 95% 2.28, 4.19; p < 0.0001). CONCLUSIONS: Mediastinitis is associated with a marked increase in mortality during the first year post-CABG and a threefold increase during a 4-year follow-up period.

Adult↗
PubMed1999

Transperineal 125iodine implantation for treatment of clinically localized prostate cancer: 5-year tumor control and morbidity.

PURPOSE: To evaluate the efficacy and toxicity of transperineal 125I implants for clinically localized prostate cancer in elderly men in a community cancer setting. METHODS AND MATERIALS: From 1988 to 1993, 206 patients, median age 77 years, with localized (Stage T1 and T2), low-grade (Gleason score < or = 7) prostate cancer were treated using pre-planned 125I transperineal implants. Patients were followed for biochemical freedom from disease, overall survival, and treatment-associated morbidity. RESULTS: The 5-year actuarial biochemical freedom from failure rate for all patients available for follow-up was 63%. Specifically, biochemical freedom from failure was 76% in patients with pretreatment PSA < or = 10 ng/ml, compared to 51% of patients with values > 10 ng/ml (median observation time 35 months). Actuarial freedom from failure for patients with PSA < or = 4 ng/ml was 84%. Stage and Gleason score did not predict outcome. PSA nadir was the strongest predictor of long-term biochemical disease-free survival (p < 0.001) with only 2 failures in 62 patients who achieved a posttreatment PSA nadir < or = 0.5 ng/ml. CONCLUSION: Transperineal 125I implants for early prostate cancer are efficacious and feasible for certain populations of elderly patients with favorable prognostic indicators in the community cancer setting. Patients with poor prognostic indicators at diagnosis do not appear to be candidates for treatment with implant alone. ( 1999 El.vit r 'Cio;noo lnc

Aged↗
PubMed1999

MediCaring: development and test marketing of a supportive care benefit for older people.

OBJECTIVES: To develop an alternative healthcare benefit (called MediCaring) and to assess the preferences of older Medicare beneficiaries concerning this benefit, which emphasizes more home-based and supportive health care and discourages use of hospitalization and aggressive treatment. To evaluate the beneficiaries' ability to understand and make a choice regarding health insurance benefits; to measure their likelihood to change from traditional Medicare to the new MediCaring benefit; and to determine the short-term stability of that choice. DESIGN: Focus groups of persons aged 65+ and family members shaped the potential MediCaring benefit. A panel of 50 national experts critiqued three iterations of the benefit. The final version was test marketed by discussing it with 382 older people (men > or = 75 years and women > or = 80 years) in their homes. Telephone surveys a few days later, and again 1 month after the home interview, assessed the potential beneficiaries' understanding and preferences concerning MediCaring and the stability of their responses. SETTINGS: Focus groups were held in community settings in New Hampshire, Washington, DC, Cleveland, OH, and Columbia, SC. Test marketing occurred in New Hampshire, Cleveland, OH; Columbia, SC, and Los Angeles, CA. PARTICIPANTS: Focus group participants were persons more than 65 years old (11 focus groups), healthcare providers (9 focus groups), and family decision-makers (3 focus groups). Participants in the in-home informing (test marketing group) were persons older than 75 years who were identified through contact with a variety of services. MEASUREMENTS: Demographics, health characteristics, understanding, and preferences. RESULTS: Focus group beneficiaries between the ages of 65 and 74 generally wanted access to all possible medical treatment and saw MediCaring as a need of persons older than themselves. Those older than age 80 were mostly in favor of it. Test marketing participants understood the key points of the new benefit: 74% generally liked it, and 34% said they would take it now. Preferences were generally stable at 1 month. In multivariate regression, those preferring MediCaring were wealthier, more often white, more often living in senior housing, and using more homecare services. However, they were not more often in poor health or needing ADL assistance. CONCLUSIONS: Older persons aged more than 80 years can understand a health benefit choice; most liked the aims of a new supportive care benefit, and 34% would change immediately from Medicare to a supportive care benefit such as MediCaring,. These findings encourage further development of special programs of care, such as MediCaring, that prioritize comfort and support for the old old.

Advance Care Planning↗
PubMed1999

Construction and characterization of a glycoprotein E gene-deleted bovine herpesvirus type 1 recombinant.

OBJECTIVE: To construct and characterize a recombinant glycoprotein (g)E gene-deleted bovine herpesvirus (BHV) type 1 (BHV-1). PROCEDURE: The BHV-1 gEgene-coding region and the flanking upstream and downstream sequences were cloned. The aforementioned cloned DNA was digested with suitable enzymes to release the amino terminal two thirds of that region, and was ligated to the beta-galactosidase (beta-gal) gene. The resulting plasmid DNA was cotransfected with DNA from full-length, wild-type (WT), BHV-1 Cooper strain of the virus. Recombinant viruses expressing beta-gal (blue plaques) were plaque purified and assayed further by blot hybridization for genetic characterization and by immunoblotting for reactivity against BHV-1 gE peptide-specific rabbit polyclonal antibody. One recombinant virus, gEdelta3.1IBR, was characterized in vitro and in vivo. The ability of the recombinant virus to induce BHV-1 neutralizing antibodies in infected calves was investigated by plaque-reduction tests. RESULTS AND CONCLUSIONS: The gEdelta3.1IBR virus contained a deletion in the viral gE gene-coding sequences where a stable chimeric reporter (beta-gal) gene was inserted. One-step growth kinetics and virus yield of the recombinant and parent viruses were similar, but early after infection, the recombinant virus yield was comparatively less. After intranasal inoculation, the recombinant gEdelta3.1IBR virus replicated in the upper respiratory tract of calves, but the amount of progeny viruses produced was hundredsfold reduced, and duration of virus shedding was shorter. Results of in vivo calf experiments and serum neutralization tests indicated that deleting the gE gene has little effect on inducing neutralizing antibodies against BHV-1, but is sufficient to reduce BHV-1 virulence in calves.

Animals↗
PubMed1994

Radon and man-made vitreous fibers.

Epidemiologic studies of miners have established a causal association between radon exposure and development of lung cancer. During the past decade the focus of attention has turned to the potential risks from exposure to radon in indoor air. Governmental involvement thus far has primarily been aimed at gathering further data and issuing voluntary guidelines for radon control in the indoor environment. The federal government's most recent risk assessment for exposure to indoor radon published in 1992 concluded that exposure to indoor radon results in 13,600 radon-induced lung cancer deaths in the United States each year. As public awareness of such environmental issues continues to grow, physicians will be faced with the need to respond to inquiries regarding potential health effects. Man-made vitreous fibers are silicate glass that have a noncrystalline structure. They have been in production for more than 100 years and are used in numerous applications in residential and commercial settings. The health risks from man-made vitreous fibers that are used in residential and commercial settings are limited to skin and occasional respiratory tract irritation under circumstances of improper installation or maintenance. When glass fiber contaminates an indoor environment, proper repair measures and thorough cleaning of the indoor environment will lead to resolution of any resultant irritant symptoms.

Air Pollutants, Radioactive↗
PubMed1994

Indoor air quality medicolegal issues.

The regulatory and legal communities have begun only recently to address the medicolegal issues surrounding indoor air quality. No single governmental agency is responsible for indoor air quality issues. The focus of the federal government's indoor air quality programs is on the gathering and dissemination of information rather than on the regulation of indoor air pollution. State and local regulatory controls vary but may include antismoking ordinances, building codes, and contractor certification programs. Numerous lawsuits involving various parties and legal theories have been filed on the basis of illness allegedly related to indoor air quality. Further regulatory and legal review of indoor air problems will likely occur in the near future, particularly as a result of the characterization of environmental tobacco smoke as a class A carcinogen.

Air Pollution, Indoor↗
PubMed1990

Analysis of movement of intrathoracic neoplasms using ultrafast computerized tomography.

Twenty patients with intrathoracic neoplasms were evaluated with ultrafast (cine) computerized tomography to determine the contribution of tumor motion to geographic errors. The treatment portals were setup with conventional simulation techniques and then scanned with cine computerized tomography. Eight tomographic levels were studied, 10 images per level over 7 seconds time. Major geographic misses were detected in three patients (15%), and minor geographic misses in an additional three (15%). The greatest tumor movement was noted in lesions located adjacent to the heart or aorta or near the diaphragm. Five of six hilar lesions showed significant lateral motion (average = 9.2 mm) with cardiac contraction, and three of four lower lobe lesions showed significant craniocaudal movement with respiration. Mediastinal lesions moved an average of 8.7 mm laterally. Lesions in the upper lobes showed minimal movement (average = 2.2 mm), and tumors attached to the chest wall showed no measurable movement.

Cineradiography↗
PubMed1990

Immunosuppressive activity of FK-506 in rats: flow cytometric analysis of lymphocyte populations in blood, spleen and thymus during treatment and following drug withdrawal.

Rats were immunized systemically with sheep red blood cells (SRBC) and given either FK-506 (1 mg/kg) or drug vehicle by i.m. injection for 7 days. In animals receiving FK-506, there was suppression (87%) of the splenic plaque-forming cell response on day 4 and marked reductions in the serum antibody titre throughout the 3-week period following immunization. Sequential flow cytometric analyses of blood lymphocytes revealed statistically significant attenuation, by FK-506, of the increase in relative numbers of OX-12+ (B) cells between days 4 and 7. Following drug withdrawal, OX-12 values remained elevated, whereas in control animals a decline was observed. These changes were reflected in concomitant increases in the relative numbers of OX-19+ (CD3+), W3/25+ (CD4+) and OX-8+ (CD8+) T cells; however, due to an overall reduction in lymphocytes by day 7, absolute values were not significantly affected compared with controls. The pattern of changes in OX-6+ (MHC class II+) cells in blood was similar to that observed for B cells. FK-506 also suppressed increases in the small proportion of blood-borne OX-40+ (activated CD4+) cells and OX-39+ (interleukin-2 receptor+) cells in the 7 day period following immunization; thereafter values for activation marker expression between treatment and control groups were similar. In the spleen, there were fewer significant differences between FK-506 and control groups in the incidences of cells expressing the above markers. OX-8+ cells, however, were significantly higher in drug-treated animals on day 7, and there were also reductions in the small proportions of OX-39+ and OX-40+ cells when compared with controls. In the thymus, reversible medullary atrophy induced by FK-506 was accompanied on day 7 by increases in the incidence of CD4+ and CD8+ cells and by a concomitant reduction in OX-44+ mature, medullary thymocytes. Two weeks after drug withdrawal, the phenotypic marker expression profile had been restored to normal in blood, spleen and thymus. These data provide new information on the apparent capacity of FK-506 to interfere with T cell maturation and its influence on lymphocyte activation in vivo.

Animals↗
PubMed1990

The influence of FK-506 on the thymus: an immunophenotypic and structural analysis.

The influence of the powerful new immunosuppressant FK-506 on the thymus was investigated in Sprague-Dawley rats that were immunized with sheep erythrocytes and treated with FK-506 (1 mg/kg/day i.m.) for 7 days. Suppression of humoral immunity in drug-treated animals was accompanied by reductions in circulating lymphocytes bearing activation markers (interleukin-2 receptor beta-chain and OX40, activated CD4+ cells) and by striking thymic medullary atrophy. There were, however, no significant differences in thymic weights or in thymocyte numbers between experimental and control groups during the period of FK-506 administration. Reduction of the medullary compartment was visualized immunohistochemically, by decreases in major histocompatibility complex (MHC) class I- and MHC class II-positive cells and in CD37+ (mature medullary) thymocytes. Flow cytometric analysis of thymocytes showed that FK-506 induced increases in bright, Thy-1.1+ cells and in numbers of CD4+ and CD8+ thymocytes, whilst CD37+ cells were less numerous than in controls. Percentages of MHC class I- and MHC class II-positive cells varied little throughout the course of FK-506 administration. Evidence of selective damage to medullary epithelial cells, attributable to FK-506, was found at both the light and electron microscopic levels, whilst thymic macrophages in drug-treated rats displayed features of enhanced phagocytic activity, including ingestion of damaged epithelial cells. These FK-506-induced abnormalities were reversed within 14 days of drug withdrawal. These findings suggest that, like cyclosporin A, FK-506 reversibly disrupts the thymic microenvironment and may interfere with the function/maturation of T lymphocytes.

Animals↗
PubMedDate not supplied

Developing staff nurse experts in nursing diagnosis-based care planning.

In this article, the authors describe the Program to Increase Nursing Knowledge and Facilitate the Utilization of Nursing Diagnosis (PINK FUND) undertaken at the Medical College of Virginia Hospitals. The program prepared unit-based nurses to be facilitators for nursing diagnosis-based care planning. Major curriculum threads included theory of nursing diagnosis, planned change, and adult learning. Instructors modeled innovative instructional methodologies for participants. Program planners vigorously marketed the program to nurses within the institution. The program succeeded in preparing nurses to use the nursing process to deliver planned care. The program description will serve as a potential model for staff development educators seeking to increase staff competence in nursing care planning and documentation.

Adult↗