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Biomedical subjects

R G Cornell

Publications and source records attributed to R G Cornell.

34 records · Page 2Linked to original sources
PubMedDate not supplied

Lack of effect of aspartame or of L-phenylalanine on photically induced myoclonus in the baboon, Papio papio.

The effects of large doses of L-phenylalanine and of aspartame on seizure susceptibility and severity have been assessed in baboons Papio papio from Senegal which show photosensitive epileptic responses similar to primary generalised epilepsy in man. L-Phenylalanine, 50, 150 or 450 mg/kg, or aspartame, 300 or 1000 mg/kg, were administered orally. Peak plasma L-phenylalanine concentrations of approximately 2000 mumoles/l occurred 1-4 h after the highest dose of L-phenylalanine or aspartame. The plasma L-phenylalanine to large neutral amino acid ratio increased approximately 30-fold at this time. Compared with water administration there were no changes in epileptic responses 1-5 h after either treatment. In this primate model of epilepsy acute increases in plasma phenylalanine concentration are neither pro- nor anticonvulsant.

Administration, Oral↗
PubMedDate not supplied

A study of vital rates near a nuclear reactor.

Radiation exposure from the Big Rock Point nuclear reactor in Charlevoix County, Michigan was investigated by studying vital rates for that county and nearby counties in comparison with other matching counties, for periods before and after the reactor began operation. None of the variables studied showed any unusual change in pattern for Charlevoix county after the rector's operation was initiated, but the trend in low-weight births was higher in Charlevoix county than in adjacent counties, whose trends were in turn higher than for the matching counties. However, no other important significant differences were found among those tested statistically, therefore, an examination of these vital rates did not substantiate an association between the proximity of the reactor and the occurrence of pathology. Nevertheless, further study should be conducted to explain the pattern of low-weight births.

Humans↗
PubMedDate not supplied

National experience with extracorporeal membrane oxygenation for newborn respiratory failure. Data from 715 cases.

In a national registry, data were collected on 715 newborn patients with severe respiratory failure supported by extracorporeal membrane oxygenation (ECMO) in 18 neonatal centers. This represents almost all infants treated with ECMO between 1980 and 1987. Eighty-one percent of the patients survived. This result is statistically significantly better than any other treatment which produces less than 78.4% survival. The most common diagnoses were meconium aspiration (310 patients, 91% survived), respiratory distress syndrome (96 patients, 78% survived), diaphragmatic hernia (121 patients, 65% survived), and sepsis (64 patients, 72% survived). Average pre-ECMO characteristics were: age 59 hours; PaO2 42 torr, PaCO2 41 torr, pH 7.40; ventilator settings FiO2 1.0, pressure 45/4 cmH2O, rate 93. Technical complications occurred in 23.1%, and physiologic complications occurred in 65.6%. Results improved with experience. Survival rate for the first ten patients from each center was 73.5% compared to 83.7% for all subsequent patients. Survival rate did not, however, significantly differ after an institutional experience of 20 patients. These observations were made on a large cohort that could not be accumulated at an individual center. These results indicate that ECMO and lung rest is appropriate and successful treatment for newborn respiratory failure unresponsive to other means of management, and that almost all respiratory failure is reversible in near-term neonates.

Female↗
PubMedDate not supplied

Integrating stratum-specific likelihood ratios with the analysis of ROC curves.

Data used to construct receiver operating characteristic (ROC) curves and to calculate the area under the curve (ROC AUC) can be used to derive stratum-specific likelihood ratios (SSLRs) with their 95% confidence intervals (95% CIs). The purpose of this study was to determine whether useful information can be obtained by adding SSLRs to the analysis of ROC curves. The authors analyzed four previously reported sets of data: 1) serum creatine kinase (SCK) for diagnosing acute myocardial infarction (AMI) in the coronary care unit (CCU); 2) SCK in the evaluation of chest pain in the emergency center (EC); 3) four predictor variables in the diagnosis of strep throat; and 4) the ordinal assessment of computed tomographic (CT) images. Use of SCK in the CCU produced four strata that had posttest probabilities that were highly discriminating, whereas SCK in the EC resulted in only two strata with limited discriminating ability. In either study the cutpoint at which the SSLR changed from less than to greater than 1.0 was higher than the reported upper normal for the test, thereby quantitating spectrum bias. The maximum number of strata of predictor signs and symptoms for strep throat was three rather than the five used in previous studies. With a larger sample size or pooling, four strata could probably be developed. With CT images, "definitely normal," "probably normal," and "questionable" were collapsed to one negative stratum. "Probably abnormal" became the true "questionable" stratum and "definitely abnormal" was the only positive stratum. The authors conclude that additional useful information is obtained by deriving stratum-specific likelihood ratios as part of the analysis of an ROC curve.

Humans↗
PubMedDate not supplied

The Michigan Ambulatory Medical Care Survey: results and utility relative to the National Survey.

Percentage distributions for variables in the Michigan Ambulatory Medical Care Survey (MAMCS), both for the Detroit Standard Metropolitan Statistical Area (SMSA) and the State as a whole, are compared with those from the National Ambulatory Medical Care Survey (NAMCS). The MAMCS data are a subset of the NAMCS data, since the MAMCS was carried out by augmenting the NAMCS in Michigan. Differences in the impact of survey results for the three areas are examined in the context of planning and developing ambulatory health care services. A specific application of survey data is examined, namely, its use in planning the Health Care Institute of Wayne State University and the Detroit Medical Center. The survey results for the three areas are similar enough to warrant the use of data from the national survey in the planning and evaluation of health services locally, although special studies of a few items such as X-ray usage may be needed. To reestablish local credibility for national results, or to detect changes in patterns which may develop, another Statelevel survey is suggested at the time of a census. Based on the experience with the MAMCS, augmentation of the NAMCS or other national surveys would be used in other States.

Ambulatory Care Facilities↗