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Biomedical subjects

C M Ryan

Publications and source records attributed to C M Ryan.

97 records · Page 6Linked to original sources
PubMedDate not supplied

A 10-year experience with toxic epidermal necrolysis.

Toxic epidermal necrolysis is a devastating medication-induced desquamation disorder with a reported mortality rate of 30% to 60% in adults. Data from previously reported series suggest that age, delay in referral to a burn center, total body surface area (TBSA) involvement, and systemic steroid treatment are poor prognostic indicators. We reviewed the records of 39 patients treated in our burn center over the past 10 years and found that the mortality rate was significantly correlated with age, thrombocytopenia, and delay in presentation. Steroid treatment and TBSA involvement were not significantly related to the mortality rate. Thirty-nine adult patients with greater than 20% TBSA epithelial necrosis were cared for in our center from January 1987 to March 1998. Wounds were treated with topical antimicrobial medications and porcine xenografts in a bacteria-controlled nursing unit. We reviewed the records of these patients for 28 clinical characteristics and looked for clinical correlates of mortality by single analysis of variance. The mortality rate was 44% (17 of 39 patients); the cause of death was most commonly multiple-organ dysfunction syndrome, for which a microbial etiologic agent was not always identified. Autopsies were performed on 11 of the 17 patients who died; there was evidence of multiple-organ damage. The patients who survived and the patients who died did not differ significantly in TBSA epithelial necrosis (66%+/-6% vs 72%+/-5%, respectively), admission platelets, number of nosocomial infections, number of complications, preadmission exposure to steroids, or extent of mucosal involvement. When compared with the patients who died, the patients who survived were (1) 20 years younger (47.5+/-4.2 years vs 64.5+/-5.3 years), (2) admitted to the hospital sooner after the onset of their rash (3.5+/-0.4 days vs 5.9+/-1.0 days), (3) much less likely to experience early thrombocytopenia (platelet nadir, 154+/-24 vs 70+/-18), (4) more likely to be febrile on presentation, and (5) less likely to have been treated with antibiotics before referral to our unit. These differences were statistically significant. The most common etiologic agents were antibiotics, anticonvulsants, and nonsteroidal anti-inflammatory drugs. Our results for a group of older patients with toxic epidermal necrolysis with extensive skin involvement suggest that age, delay in hospitalization, thrombocytopenia, and early empiric antibiotic treatment are associated with a poor prognosis.

Adult↗
PubMedDate not supplied

Neuropsychological performance of young men who vary in familial risk for hypertension.

Neuropsychological performance was examined as a function of parental history of hypertension. Thirty-five normotensive offspring of two hypertensive parents (PH+/+) were compared to 35 offspring of two normotensive parents (PH-/-) and 35 offspring of one hypertensive and one normotensive parent (PH+/-) on tests of abstract reasoning, attention/mental flexibility, memory, perception, psychomotor skills, and visuospatial/constructional abilities. Results indicated that PH+/+ offspring performed more poorly than PH-/- offspring on tests of visuospatial/constructional and visuoperceptual ability; PH+/- offspring tended to score lower than PH-/- offspring on these tests. These findings were independent of age, education, diastolic blood pressure levels, average alcohol consumption, trait anxiety, and depression. Results of this study may indicate subtle central nervous system involvement associated with familial risk for hypertension.

Adolescent↗
PubMedDate not supplied

Serum cholesterol and intellectual performance.

OBJECTIVE: The current investigation sought to determine whether intellectual performance is related to serum lipid concentrations. METHODS: Subjects were 177 healthy, Caucasian adult males and females, aged 25 to 60 years, with widely varying total cholesterol concentrations. Crystallized intelligence was estimated from the Information and Vocabulary subtests of the Wechsler Adult Intelligence Scale, Revised (WAIS-R). Fluid intelligence was estimated from the WAIS-R Block Design subtest, and from a computerized version of the Letter Rotation test. RESULTS: Controlling for age, better performance on both Information and Vocabulary subtests was associated with lower total and low-density lipoprotein (LDL) cholesterol and triglyceride concentrations (r's = -.24 to -.35, p's < .005). In contrast, better performance on Block Design was correlated with higher total and LDL cholesterol (r's = .22 to .23, p's < .005). Letter rotation response latency was unrelated to serum lipids. CONCLUSION: These opposing relationships between serum cholesterol and different dimensions of intellectual performance, on the one hand, may reflect the propensity of knowledgeable individuals to consume low fat diets, and on the other hand, suggest that serum cholesterol concentration may be a correlate of brain nutrients important to mental efficiency.

Adult↗
PubMedDate not supplied

Hypoglycemia in children with insulin-dependent diabetes mellitus.

The promotion of normal growth and development and the avoidance of acute and long-term complications are overall goals in the management of a child with insulin-dependent diabetes mellitus. Recent studies provide new and pertinent information about the acute effects of hypoglycemia on such cognitive functioning as learning, memory, reading, and visuospatial skills. The effects of early onset diabetes on school performance are also discussed. This information should be incorporated by diabetes educators into the educational plan for children with IDDM, their families, and schools.

Achievement↗
PubMedDate not supplied

The metabolic basis of the increase of the increase in energy expenditure in severely burned patients.

BACKGROUND: Severe burn trauma is characterized by an elevated rate of whole-body energy expenditure. APPROACH: In this short review, we have attempted to assess the metabolic characteristics of and basis for the persistent increase in energy expenditure during the flow phase of the injury. We consider some aspects of normal energy metabolism, including the contribution of the major adenosine triphosphate (ATP)-consuming reactions to the standard or basal metabolic rate. Rate estimates are compiled from the literature for a number of these reactions in healthy adults and burned patients, and the values are related to the increased rates of whole-body energy expenditure with burn injury. RESULTS: Whole-body protein synthesis, gluconeogenesis, urea production, and substrate cycles (total fatty acid and glycolytic-gluconeogenic) account for approximately 22%, 11%, 3%, 17%, and 4%, respectively, of the burn-induced increase in total energy expenditure. CONCLUSIONS: These ATP-consuming reactions, therefore, seem to explain approximately 57% of the increase in energy expenditure. The remainder of the increase may be due, in large part, to altered Na(+)-K(+)-ATPase activity and increased proton leakage across the mitochondrial membrane.

Adenosine Triphosphate↗
PubMedDate not supplied

Ice formation in isolated human hepatocytes and human liver tissue.

Cryopreservation of isolated cells and tissue slices of human liver is required to furnish extracorporeal bioartificial liver devices with a ready supply of hepatocytes, and to create in vitro drug metabolism and toxicity models. Although both the bioartificial liver and many current biotoxicity models are based on reconstructing organ functions from single isolated hepatocytes, tissue slices offer an in vitro system that may more closely resemble the in vivo situation of the cells because of cell-cell and cell-extracellular matrix interactions. However, successful cryopreservation of both cellular and tissue level systems requires an increased understanding of the fundamental mechanisms involved in the response of the liver and its cells to freezing stress. This study investigates the biophysical mechanisms of water transport and intracellular ice formation during freezing in both isolated human hepatocytes and whole liver tissue. The effects of cooling rate on individual cells were measured using a cryomicroscope. Biophysical parameters governing water transport (Lpg = 2.8 microns/min-atm and ELp = 79 kcal/mole) and intracellular heterogeneous ice nucleation (omega het = 1.08 x 10(9) m-2s-1 and kappa het = 1.04 x 10(9) K5) were determined. These parameters were then incorporated into a theoretical Krogh cylinder model developed to simulate water transport and ice formation in intact liver tissue. Model simulations indicated that the cellular compartment of the Krogh model maintained more water than isolated cells under the same freezing conditions. As a result, intracellular ice nucleation occurred at lower cooling rates in the Krogh model than in isolated cells. Furthermore, very rapid cooling rates (1000 degrees C/min) showed a depression of heterogeneous nucleation and a shift toward homogeneous nucleation. The results of this study are in qualitative agreement with the findings of a previous experimental study of the response to freezing of intact human liver.

Cell Communication↗