Biomedical subjects
R Cohen
Publications and source records attributed to R Cohen.
Rorschach correlates of time estimation.
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Health care system and medical education in Canada. 1. Review of the health care context in a time of change.
Over the past three decades Canada has developed an exemplary system of universal health care. However, current financial constraints threaten to undermine the very foundation of the system that represents Canada's respect for social justice. The first of these two articles (Part 1) discusses the unique characteristics of the system, a comparative view of universal health care systems, the reaction of the medical profession to governmental control, and finally the funding and manpower shortages that are compelling a review of the values and organization that have sustained the system thus far. The second article (Part 2) reviews the organization and funding of medical education and the impact of some critical changes in the health care system on postgraduate medical education. Issues related to new licensure and certification requirements, changing population demographics and approaches to health care delivery, manpower needs, and the attitude and expectations of the public are discussed.
Health care system and medical education in Canada. 2. Impact of changes in the health care system on medical education.
Over the past three decades Canada has developed an exemplary system of universal health care. However, current financial constraints threaten to undermine the very foundation of the system that represents Canada's respect for social justice. The first of these two articles (Part 1) discusses the unique characteristics of the system, a comparative view of universal health care systems, the reaction of the medical profession to governmental control, and finally the funding and manpower shortages that are compelling a review of the values and organization that have sustained the system thus far. The second article (Part 2) reviews the organization and funding of medical education and the impact of some critical changes in the health care system on postgraduate medical education. Issues related to new licensure and certification requirements, changing population demographics and approaches to health care delivery, manpower needs, and the attitude and expectations of the public are discussed.
Effects of awareness and motor involvement on autonomic conditioning in chronic schizophrenics.
Chronic schizophrenics under neuroleptic medication were compared with normals, matched for age and education, in two conditioning experiments. Both experiments employed a differential paradigm with long conditional stimulus--unconditional stimulus (CS-UCS) intervals. Skin resistance (SR) and finger pulse or heart rate (HR) were recorded. In Experiment 1, half of the subjects were trained in categorizing the to-be conditional stimuli. In a further step, half of the subjects were informed about the CS-UCS contingency. The UCS was an electric shock. Information improved discrimination of SR responses only of normals, and discrimination training had no effect at all on autonomic responses. In Experiment 2, only electrodermal responders were included. Each subject was tested in two sessions, using a loud tone as UCS in one, and a reaction time signal in the other. Again, half of the subjects wee informed about the contingency. Information improved discrimination of SR responses of both diagnostic groups. Decelerations of HR following CS onset showed informed schizophrenics to discriminate better with the loud tone UCS than with the reaction time signal. General autonomic responsivity seems to determine not only discriminative conditioning of schizophrenic patients but also the reports of awareness and the effects of manipulations of awareness. However, when subjects are matched for electrodermal responsivity and are equivalent in terms of SR response conditioning, patients react to information about the contingency with enhanced HR deceleration to the CSs, possibly reflecting a heightened sensitivity of the cardiovascular system.
Alzheimer's disease. How memory fails: a theoretical model.
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The antibiotic treatment of acute otitis media and sinusitis in children.
The development of resistance among the bacterial pathogens causing acute otitis media and sinusitis in children is causing considerable concern. Although normally a mild infection, acute otitis media can produce serious complications with sequelae that can have long-lasting effects. High levels of resistance are now being seen in the three principal pathogens. Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Most clinical trials comparing the efficacy of different antibiotics have failed to show differences in clinical efficacy. To overcome this problem, alternative methods of assessing antibiotics have been developed including the "in-vivo sensitivity test" proposed by Howie and retrospective analyses of treatment failures. The treatment of sinusitis is complicated by the difficulty in establishing a clear differential diagnosis. To date, no definitive trials of bacteriologic efficacy in children have been published.
Effect of an abnormal sperm chromatin structural assay (SCSA) on pregnancy outcome following (IVF) with ICSI in previous IVF failures.
A high DNA fragmentation index (DFI) when performing the sperm chromatin structural (SCSA) assay was claimed to be so specific for male subfertility that even IVF and ICSI did not result in live pregnancies. The present study was designed to corroborate or refute these findings. The SCSA test was performed on the male partner from couples failing to have a successful pregnancy despite at least 2 previous IVF attempts. In contrast to the aforementioned studies, ongoing pregnancies were found despite working with a group of recalcitrant patients. Nevertheless, a high DFI score was associated with a trend for lower ongoing pregnancy rates especially related to a high miscarriage rate. Other more recent studies seem to support our conclusions. A high DFI score should influence a patient to choose IVF as a therapeutic modality sooner, especially with ICSI.
Role of complement activation in hypersensitivity reactions to doxil and hynic PEG liposomes: experimental and clinical studies.
Pegylated liposomal doxorubicin (Doxil) and 99mTc-HYNIC PEG liposomes (HPL) were reported earlier to cause hypersensitivity reactions (HSRs) in a substantial percentage of patients treated i.v. with these formulations. Here we report that (1) Doxil, HPL, pegylated phosphatidylethanolamine (PEG-PE)-containing empty liposomes matched with Doxil and HPL in size and lipid composition, and phosphatidylglycerol (PG)-containing negatively charged vesicles were potent C activators in human serum in vitro, whereas small neutral liposomes caused no C activation. (2) Doxil and other size-matched PEG-PE and/or PG-containing liposomes also caused massive cardiopulmonary distress with anaphylactoid shock in pigs via C activation, whereas equivalent neutral liposomes caused no hemodynamic changes. (3) A clinical study showed more frequent and greater C activation in patients displaying HSR than in non-reactive patients. These data suggest that liposome-induced HSRs in susceptible individuals may be due to C activation, which, in turn, is due to the presence of negatively charged PEG-PE in these vesicles.
Port-access bilateral internal mammary artery grafting for left main coronary artery disease: canine feasibility study.
BACKGROUND: To extend the applications of minimal access cardiac surgery, an endovascular cardiopulmonary bypass (CPB) system that allows cardioplegia delivery and cardiac venting was used to perform bilateral internal mammary artery (IMA) bypass grafting in six dogs. METHODS: The left IMA (LIMA) was taken down thoracoscopically from three left lateral chest ports, followed by the right IMA (RIMA) from the right side. One left-sided port was extended medially 5 cm with or without rib resection, to expose the pericardium. Both IMAs were divided and exteriorized through the left anterior mediastinotomy. Flow and pedicle length were satisfactory in all cases. Femoral-femoral bypass was used and the heart arrested with antegrade delivery of cardioplegic solution via the central lumen of a balloon catheter inflated to occlude the ascending aorta. All anastomoses were made through the mediastinotomy under direct vision. In five studies the RIMA was attached to the left anterior descending artery (LAD) and the LIMA to the circumflex, and in one study the RIMA was tunneled through the transverse sinus to the circumflex and the LIMA was anastomosed to the LAD. All animals were weaned from CPB in sinus rhythm without inotropes. CPB duration was 108 +/- 27 minutes (mean +/- SD) and the clamp duration was 54 +/- 10 minutes. RESULTS: Preoperative and postoperative cardiac outputs were 2.9 +/- 0.71/min and 2.4 +/- 0.31/min, respectively (p = NS), and corresponding pulmonary artery occlusion pressures were 6 +/- 3 mmHg and 7 +/- 2 mmHg, respectively (p = NS). All 12 grafts were demonstrated to be fully patent. Postmortem examination revealed well aligned pedicles and correctly grafted target vessels. CONCLUSION: This canine model demonstrates the potential for a less invasive approach to the surgical management of left main coronary artery disease in humans.
Cognitive orientation for patients in group psychotherapy.
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Comparison of immunoassays for tumor markers CA 19-9, CA 15-3 and CA 125: data from an international quality assessment scheme.
Data collected in the 1993 and 1994 cycles of an international external quality assessment (EQA) program and in a national multicenter collaborative study were cumulatively analyzed to evaluate the standardization of the methods currently in use for the assay of mucinous tumor markers CA 19-9, CA 15-3 and CA 125. On average the between-laboratory variability was 15.2 and 16.0 CV% for CA 15-3 and CA 125 respectively; the between-laboratory variability found for CA 19-9 was markedly worse (mean 28.3 CV%). The variability component attributable to systematic differences between different methods/kits was relatively small for CA 15-3 and CA 125 (18% and 24% of the total variability) but markedly larger for CA 19-9 (48% of the total variability). The agreement of CA 19-9 results worsened in the last few years when new nonisotopic techniques became available. The precision of the methods/kits most used in the survey ranged from 9.9 to 13.3 CV% for CA 125 and from 11.6 to 13.9 CV% for CA 15-3. For these two tumor markers the precision of the traditional IRMAs does not appear different from that of the new fully automated nonisotopic techniques. The precision of CA 19-9 methods was on average worse (from 11.7 to 19.6 CV%) although two automated systems exhibited a precision better than that of IRMAs. In conclusion, the results of this study indicate that CA 15-3 and CA 125 are satisfactorily assayed whereas CA 19-9 assay appears affected by larger differences between methods and by poorer precision of laboratories and kits.
Recombinant DNA technology: a 20-year occupational health retrospective.
During the past 20 years of recombinant DNA research and its commercial applications, neither unique occupational-health risks nor adverse effects from accidental occupational recombinant microorganisms has been reported. Such injuries as acid splashes, CNS-depressant effects from over-exposure to solvents, and infections may occur in all types of chemistry and microbiology laboratories. Because of the relative inexperience with the emerging technology of gene therapy, however, including possible vector replication or recombination, further vigilance in monitoring the safety of their applications is required.
Comparison of maternal absenteeism and infant illness rates among breast-feeding and formula-feeding women in two corporations.
PURPOSE: A comparison was made between breast-feeding and formula-feeding among employed mothers. Absenteeism directly related to child care was examined. DESIGN: This quasi-experimental study followed convenience samples of breast-feeding and formula-feeding mothers until their infants were weaned or reached 1 year of age. SETTING: Two corporations with established lactation programs were used. One had approximately 100 births annually among 2400 female employees, and the other had approximately 30 births annually among 1200 female employees. SUBJECTS: A sample of 101 participants, 59 feeding breast milk and 42 using commercial formula, was composed of employees returning from maternity leave for a medically uncomplicated birth. INTERVENTION: The programs provided counseling by a lactation professional for all participants and facilities to collect and store breast milk. MEASURES: Confidential participant diaries provided descriptive data on infant illnesses and related absenteeism that the lactation consultant verified with health care providers and through employer attendance records. ANALYSIS: Attribute counts of illnesses and absenteeism were reported as percentages. Single degree of freedom chi square tests were used to compare rates between nutrition groups. RESULTS: Approximately 28% of the infants in the study had no illnesses; 86% of these were breast-fed and 14% were formula-fed. When illnesses occurred, 25% of all 1-day maternal absences were among breast-fed babies and 75% were among the formula-fed group. CONCLUSIONS: In this study fewer and less severe infant illnesses and less maternal absenteeism was found in the breast-feeding group. This was not an experimental study. Participants were self-selected, and a comparison group was used rather than a true control group. Corroboration of these findings from larger experimental studies is needed to generalize beyond these groups.
The impact of two corporate lactation programs on the incidence and duration of breast-feeding by employed mothers.
PURPOSE: The goal of this study was to examine the impact of two corporate lactation programs on breast-feeding behavior among employed women. DESIGN: Breast-feeding behavior was measured for up to one year among women who had given birth during 1989, 1990, 1991, and 1992 and compared with national norms. SETTING: The study was conducted at two corporations: a utilities company with 11,000 employees of which 22% were female with approximately 100 births each year and a space corporation with 3,900 employees of which 31% were female with approximately 30 births per year. SUBJECTS: Participants were 187 employees returning to work following maternity leave for a medically uncomplicated birth. INTERVENTION: Participants collected and stored breast milk using the worksite breast pump room at scheduled times during the workshift and were counseled by a lactation professional throughout the study. MEASURES: A questionnaire was used to establish breast-feeding behavior. Duration was reported by the lactation professional. RESULTS: Since program inception, 75% of the participants who returned to work while breast-feeding continued until their child was six months old. This represented 139 of the 187 mothers at the two companies. Average duration of breast-feeding overall was 8.1 months. DISCUSSION: Participants were able to maintain a breast-feeding regimen for at least six months at rates equivalent to the statistical norms for women who are not employed outside the home. This was not an experimental study. Participants were self-selected and there was no control group. On a year-to-year basis, the numbers of participants were relatively small.(ABSTRACT TRUNCATED AT 250 WORDS)
Computerized data enhance hazardous materials incidence response.
The use of data processing to enhance job performance in emergency situations has had only limited application. In 1984, Middlesex Borough developed the first computerized hazardous material response program in New Jersey. A task force was formed to identify resources, needs, solutions and to actually put the program in place. Training programs and field drills were conducted for emergency personnel. Priority selection was based on risk assessment by the inspection staff. A system was developed that would be compatible with the federal emergency computer so as to broaden the information base. In 1985, the first full year of operation, there were three major emergencies in the Borough. In each case, the responders had an instantaneous computer printout providing data for rapid decisions, as well as a computer sketch of the plant and all its facilities. This enabled a higher level of protection for the public, the affected industry and the emergency responders.
[Quality specifications and allowable standards for validation of methods used in clinical biochemistry].
The purpose of this work is to provide, for a large number of analysis in the field of clinical biochemistry, appropriate criteria for the evaluation of the performance of in vitro diagnostic methods. Based on a first set of data established in 1986 and the experience cumulated by organisers in charge of internal and external quality assessment surveys, an expert group has proposed acceptable limits for a large list of analysis (n = 116). Data are reported and presented in tables divided into 7 chapters including: general biochemistry, enzymes, proteins, tumour markers, hormones, drugs (and toxic), and urinary analysis. For each analysis are given: analytical and reference ranges, three concentration levels for control specimens to be used during evaluations and the range of values within which they can be chosen, reproducibility and repeatability limits expressed as CV%. Maximal tolerable systematic error and inaccuracy are given for control and biological specimens and compared to those obtained using a reference or validated method. These data are essential for evaluations using the protocol designed by the SFBC and can serve as quality criteria for the choice and validation of in vitro diagnostic systems.
Switch to non-CFC inhaled corticosteroids: a comparative efficacy study of HFA-BDP and CFC-BDP metered-dose inhalers.
Inhaled corticosteroids, such as beclomethasone dipropionate (BDP), recommended for the treatment of persistent, mild, moderate, or severe asthma, have traditionally been administered via chlorofluorocarbon (CFC) propellant. The imminent phasing out of CFCs from pharmaceutical preparations due to the Montreal Protocol means patients will have to switch to a CFC-free alternative. One such preparation is hydrofluoroalkane-BDP (HFA-BDP), a press-and-breathe metered-dose inhaler. This 8-week, open-label, multicentre study assessed asthma control in patients switching from CFC-BDP to HFA-BDP (QVAR). Patients with asthma, stabilised on 400-1600 micrograms/day CFC-BDP, were randomised to HFA-BDP (354 patients; 75%) at half their current daily dose of CFC-BDP, or to CFC-BDP (119 patients; 25%). HFA-BDP efficacy was found to be equivalent to that of CFC-BDP in that no statistically significant difference was observed between the two groups in the mean change from baseline in a.m. PEF (95% CI within +/- 11 l/min). No statistically significant differences were observed between the two groups for increased asthma symptoms or acute asthma episodes. We conclude that asthma control was maintained over 8 weeks, with few asthma exacerbations, in patients switching from previous CFC-BDP therapy to HFA-BDP at half the dose.