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Biomedical subjects

D McKee

Publications and source records attributed to D McKee.

At least 19 recordsLinked to original sources
PubMed1997

Phosphatidylcholine coated chest drains: are they better than conventional drains after open heart surgery?

INTRODUCTION: Inadequate thoracic drainage after open heart surgery has serious deleterious consequences. Thrombus formation within the chest drains is primarily responsible for the occlusion of chest drains. Chest drains coated with derivatives of phosphatidylcholine (PC), commonest phospholipid on cell membranes, potentially have a less thrombogenic surface. MATERIALS AND METHODS: In a prospective randomised double blind study, we compared PC-coated drains (Group I, n = 25) with non coated drains (Group II, n = 26) after open heart surgery. Drain performance, post-operative complications and clinical course were compared. RESULTS: PC-coated drains had a significantly shorter period of drainage, 20.4 +/- 1.0 versus 28.9 +/- 3.7 h (P < 0.05). Otherwise, mean volume drained, number clots removed from drain and the ease of drainage of the two types of drains were similar. There were no significant differences in the incidence of post-operative pericardial effusions, dysrhythmias, ambulation time and hospital stay. CONCLUSIONS: We conclude that the PC coated drains may be of importance in cases where prolonged drainage is anticipated otherwise they have no significant advantage.

Adult↗
PubMed1996

Myocardial dysfunction after successful resuscitation from cardiac arrest.

OBJECTIVE: To investigate the functional and metabolic changes in the myocardium after successful resuscitation from cardiac arrest. DESIGN: Prospective, randomized, sham-controlled study. SETTING: Animal laboratory at a university center. SUBJECTS: Domestic pigs. INTERVENTIONS: Electric induction of ventricular fibrillation by alternating current delivered to the right ventricular endocardium through a pacing electrode. Electric defibrillation was attempted after an interval of 12 mins of ventricular fibrillation, which included 4 mins of untreated ventricular fibrillation and 8 mins of precordial compression in 13 animals, seven of which were successfully resuscitated. Seven additional animals were randomized to serve as "sham" controls, in which cardiac arrest was not induced. MEASUREMENTS AND MAIN RESULTS: Left ventricular pressure-volume relationships utilizing the conductance method were obtained in conjunction with conventional hemodynamic and metabolic measurements at baseline and during a 6-hr interval after successful cardiac resuscitation. Progressive and striking increases in left ventricular volumes were observed after successful cardiac resuscitation. The end-diastolic volume increased from a prearrest level of 89 +/- 21 mL to a maximum of 154 +/- 53 mL (p<.05) at 360 mins after successful resuscitation. The time-coincident end-systolic volume increased from 54 +/- 21 to 126 +/- 54 mL (p<.05), such that the ejection fraction was reduced from 0.41 +/- 0.10 to 0.20 +/- 0.07 ( p<.05). Ventricular dilation was associated with marked reductions in stroke volume and ventricular work. However, compensatory increases in heart rate maintained cardiac output at levels that sustained adequate systemic oxygen delivery. The slope of the end-systolic pressure-volume relationships progressively decreased from 5.04 +/- 1.88 to 2.00 +/- 0.57 mm Hg/mL (p<.05) at 360 mins after successful resuscitation. The volume intercept at left ventricular pressure of 100 mm Hg increased from 43 +/- 19 to 94 +/- 51 mL (p=.03). Both the decrease in the slope and the increase in the volume intercept were characteristic of progressive impairment in contractile function. The rate of left ventricular pressure decrease was unchanged. Accordingly, no substantial changes in lusitropic properties were identified. Despite large increases in end-diastolic volume, the end-diastolic pressure remained unchanged. CONCLUSION: Postresuscitation myocardial dysfunction in this animal model was characterized by impaired contractile function, decreased work capability, and ventricular dilation.

Animals↗
PubMed1995

Assessment of alcohol and other drug disorders in the seriously mentally ill.

Brief assessment methods are needed to determine the presence of alcohol and drug problems in persons with severe mental illness. The purposes of this study were to determine the prevalence of alcohol and other drug problems in a rural population of 253 clients with severe mental illness and to determine the accuracy of case manager responses to specific alcohol and drug assessment questions about their clients. Clients were assessed for the presence of past and present alcohol and drug disorders by means of a face-to-face diagnostic interview. The specific questions the case managers were asked to complete were designed to assess the quantity and frequency of recent alcohol and drug use and the presence of three criteria for alcohol or drug dependence and to differentiate present versus past history of substance problems. On the basis of the Diagnostic Interview Schedule- Revised, 35 percent of the clients met current DSM-III-R alcohol or drug criteria for abuse, dependence, or both. There were differences between client and case manager reports on the clients' use of alcohol, marijuana, cocaine, narcotics, and unprescribed tranquilizers in the last year. The best predictor of a client's present alcohol or drug problem was whether the case manager thought that the client had substance use problems at some time in his or her life (sensitivity = 0.86, specificity = 0.75). This report provides additional evidence that case manager reports are a valid method of determining the prevalence of substance use problems in persons with severe mental illness.

Adult↗
PubMed1995

Mechanisms of myocardial hypercarbic acidosis during cardiac arrest.

During the global myocardial ischemia of cardiac arrest and during regional myocardial ischemia due to local impairment of coronary blood flow, intramyocardial carbon dioxide tensions (Pmco2) of ischemic myocardium increase to levels exceeding 400 Torr. The mechanism of such myocardial hypercarbic acidosis is as yet incompletely understood, specifically whether these increases in Pmco2 are due to increased oxidative metabolism, decreased CO2 removal, or buffering of metabolic acids. We therefore measured Pmco2 and the total CO2 content of rat hearts harvested before, during, and after resuscitation from cardiac arrest. Pmco2 significantly increased from an average of 63 to 209 Torr during a 4-min interval of untreated ventricular fibrillation. This was associated with concurrent decreases in intracellular pH from an average of 7.03 to 6.02 units. The total CO2 content of the myocardium simultaneously decreased from 17.0 to 16.5 mmol/kg. Accordingly, increases in Pmco2 and [H+] were observed in the absence of increases in the total CO2 content and therefore the calculated myocardial bicarbonate. These observations in the rat model implicate buffering of metabolic acids by bicarbonate rather than increases in CO2 production or decreases in CO2 removal as the predominant mechanism accounting for myocardial hypercarbia.

Acidosis↗
PubMed1993

Glycogen branching enzyme deficiency in adult polyglucosan body disease.

Branching enzyme activity was assayed in muscle, peripheral nerve, and leukocytes from 2 Ashkenazi-Jewish patients with adult polyglucosan body disease and 1 African-American and 3 Caucasian patients with the same clinical and pathological features. Branching enzyme activity was normal in the muscle specimens from both Jewish and non-Jewish patients. However, the activity was markedly decreased not only in the leukocytes from the 2 Jewish patients (confirming previous findings), but also in peripheral nerve specimens, whereas it was normal in nerve tissue and leukocytes from all non-Jewish patients. These data confirm a branching enzyme deficiency in a subgroup of patients with adult polyglucosan body disease, and show that the defect is tissue-specific, suggesting that adult polyglucosan body disease has more than one biochemical basis.

1,4-alpha-Glucan Branching Enzyme↗
PubMed1993

Staffing patterns in rural community support programs.

OBJECTIVE AND METHODS: Rural mental health programs are thought to have difficulty recruiting and retaining qualified staff and to have excessively large caseloads per staff member. The authors surveyed 12 community support programs in small cities and rural areas of Wisconsin to determine staff size and characteristics, staff-to-client ratios, and the relative use of paraprofessional staff and professional staff, excluding psychiatrists. RESULTS: The programs surveyed had an average of 5.6 full-time-equivalent caregiving staff and an average caregiver-to-client ratio of 1 to 13. Caregiving staff were predominantly female, had been in the mental health field a mean of 8.8 years, and received an average salary of $20,732. Although program directors indicated that about one-fifth of staff left in the previous year, they reported little difficulty recruiting staff. Thirty-eight percent of all caregivers were paraprofessionals; in several programs, more than half the caregivers were paraprofessionals. Use of paraprofessionals is more common in rural programs; thus caregivers in those programs are likely to have lower levels of salary and experience. CONCLUSIONS: The community support programs in the sample employed experienced caregivers and had staff-to-client ratios that were close to the ratio recommended for such programs by Wisconsin legislation. The survey findings suggest that claims of acute staffing problems in rural community support programs need to be examined more closely, with attention to the relationship between staff characteristics and client outcomes.

Adult↗
PubMed1992

Validity of case manager reports of clients' functioning in the community: independent living, income, employment, family contact, and problem behaviors.

Validity of case manager reports of client functioning in the community was assessed by examining the correspondence between case manager reports and client reports of several widely-used indicators of client well-being, including independent living, income, employment, family contact, and problem behaviors. Effects of how well case managers knew their clients and of using telephone interviews vs. self-administered questionnaires to gather case manager data were also investigated. Data were gathered from 6 case managers and 55 of their seriously mentally ill clients in a rural Wisconsin Community Support Program. Indicators of independent living and employment displayed reasonably good agreement and support the use of case manager reports in research. Indicators of income and problem behaviors produced lower levels of client-case manager agreement at least in part because client reports proved an inadequate criterion for these measures.

Activities of Daily Living↗
PubMed1990

Comparing a Christian physicians' support group with the Balint Group.

The influence of religious beliefs on physicians' social attitudes and medical practices is not as yet adequately discussed in the literature. This paper describes a Christian physician support group and contrast it with the more traditional Balint model support group. Issues of membership, leadership, and use of the group are discussed. The potential use and misuse of religiously oriented support groups are outlined. Thirteen Christian physician members of a study group were given questionnaires regarding participation in and expectations of the group. They were asked to comment on the extent to which their religious convictions influenced their practice of medicine. Participants discussed a wide range of issues both personal and professional. They benefited from the opportunity to share views with others who brought a spiritual perspective to patient care. Members stated that their spiritual beliefs influenced their attitudes toward social issues, such as abortion and divorce, and their practice of medicine, for example, by praying with and for their patients. The group provided a safe place to explore these beliefs.

Adult↗
PubMed1990

Unmeasured anion during severe sepsis with metabolic acidosis.

It is assumed that the development of metabolic acidosis during sepsis is secondary to lactic acidosis. We assessed the composition of the anion gap during severe sepsis induced by cecal perforation in rats. In the first experiment, cardiac output, arterial blood gases, and arterial lactate were measured over a 6 hr interval in five septic rats and in five rats serving as sham-operated controls. The cardiac output decreased from 331 +/- 32 to 172 +/- 9 ml/kg/min (P less than 0.01) in the septic rats. Although the arterial lactate was increased to 2.1 +/- 0.2 mEq/L in septic rats compared to 0.8 +/- 0.1 mEq/L in sham rats (P less than 0.01), the HCO3- was decreased to 16.5 +/- 0.6 mEq/L in septic rats versus 23.8 +/- 1.10 mEq/L in sham rats (P less than 0.01). We further investigated this bicarbonate deficit in a second study in which arterial blood was sampled at 6 hr for blood gases, and plasma Na+, K+, Cl-, HCO3-, lactate, pyruvate, beta-hydroxybutyrate, acetoacetate, citrate, creatinine, albumin, and amino acids in five septic and five sham rats. The serum anion gap was calculated as [(Na(+) + K+) - (Cl(-) + HCO3-)]. The anion gap was 21.6 +/- 1.6 mEq/L in the septic animals as compared to 13.2 +/- 0.5 mEq/L in the sham animals (P less than 0.01). There were no differences in the concentration of pyruvate, beta-hydroxybutyrate, acetoacetate, citrate, creatinine, albumin, or amino acids.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1987

Effect of Duchenne muscular dystrophy on enzymes of energy metabolism in individual muscle fibers.

Individual muscle fibers from patients with Duchenne muscular dystrophy at an early stage in their disease, and from apparently normal boys of similar age, were analyzed for 13 enzymes of energy metabolism. This approach avoided the serious problems with muscle homogenate assays from increases in nonparenchymal components and permitted assessment of disease changes in different fiber types. Some enzymes of glycogenolysis (phosphorylase, phosphoglucomutase, and pyruvate kinase) were decreased in dystrophic fibers of all types. Phosphofructokinase was decreased in presumptive type II fibers. Lactate dehydrogenase was increased in type I fibers and essentially unchanged in type II. Phosphoglucoisomerase was near normal. Two enzymes of glucose metabolism not involved in glycogenolysis, hexokinase and glycogen synthase, were near normal, but a third, fructose bisphosphatase, was sharply reduced. Two enzymes of oxidative metabolism, citrate synthase, and beta-hydroxyacyl CoA dehydrogenase, were unchanged or increased. Two enzymes of high energy phosphate transfer, creatine kinase and adenylokinase, were only marginally affected. The net result is to leave the type II fibers, which normally exert the greatest force, with a severe deficit in the glycogenolytic enzyme machinery to maintain that force.

Adenylate Kinase↗
PubMed1980

Enzyme levels in individual rat muscle fibers.

Individual muscle fibers from the rat anterior tibialis and soleus muscles were each analyzed in duplicate for lactate dehydrogenase (LDH, EC 1.1.1.27), malate dehydrogenase (MDH, EC 1.1.1.37), 3-hydroxyacyl-CoA dehydrogenase (EC 1.1.1.35), fumarate hydrotase (EC 4.2.1.2), glycogen phosphorylase (EC 2.4.1.1), 6-phosphofructokinase (EC 2.7.1.11), pyruvate kinase (EC 2.7.1.40), fructose-bisphosphatase (EC 3.1.3.11), and creatine kinase (EC 2.7.3.2). A few fibers were also analyzed for adenylate kinase (EC 2.7.4.3). In general, there was a wide and almost continuous spectrum of coordinated enzyme activities. In the tibialis muscle, two fiber groups could be clearly distinguished on the basis of MDH activity. The high MDH group had on the average lower LDH activity, but there was a great deal of overlap in LDH between the two groups. Less overlap was observed for phosphorylase and fructose-bisphosphatase, both inversely related to MDH. Only one main group of fibers (presumably slow twitch) was found in the soleus muscle, although enzyme activities also covered a wide range. These soleus fibers were clearly distinguished from the high MDH tibialis group by much lower activities of LDH, pyruvate kinase, and fructose-bisphosphatase.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1980

Gallium scanning in Paget's disease of bone: effect of calcitonin.

Calcitonin has been used in the treatment of Paget's disease of bone, and serum alkaline phosphatase level and 24 hr urinary hydroxyproline excretion have been used to follow therapeutic response. The radionuclide bone scan has been used as a visual indicator; however, there is some uncertainty as to its value in following changes in disease activity. Four patients with both serial technetium phosphate bone scans and serial gallium studies were studied. In each case the beneficial effect of calcitonin was demonstrated more accurately with gallium than with technetium diphosphonate. Since biochemical changes in Paget's disease are believed to be mediated at the cellular level and gallium uptake depends on cellular activity, it is proposed that gallium uptake is a more appropriate measure of the activity of Paget's disease than a noncellular marker such as a technetium-containing bone scan agent.

Calcitonin↗
PubMed1977

Evaluation of 99mTc diphosphonate kinetics and bone scans in patients with Paget's disease before and after calcitonin treatment.

Eleven patients with Paget's disease of bone underwent serial total body bone scars before and after therapy with calcitonin. All patients studied showed improvement clinically as well as biochemically. Scan improvement was noted in patients with mild disease. Patients with severe disease showed either to change or only slight improvement on the serial bone scars The scan was of greatest value in determining the extent of disease, especially in 3 patients in whom biochemical values were normal. A single pulse injection of 50 M.R.C. units of salmon calcitonin produced a significant increase in the blood clearance of 99mTc diphosphonate. The mechanism of this effect is not clear from this study.

Bone and Bones↗