Neuropsychological assessment and the Disability Rating Scale (DRS): a concurrent validity study.

Assessment of current level of functioning among clients with traumatic brain injury (TBI) often guides the establishment of realistic outcome goals for post-acute rehabilitation. Further, data generated from neuropsychological testing provide a clinician with a better understanding of a client's pattern of cognitive strengths and weaknesses. The Disability Rating Scale (DRS) is commonly used by TBI rehabilitation facilities to assess a client's general level of functioning in terms of impairment, disability, and handicap. Previous studies have used clients' neuropsychological test results to predict future level of functioning. These studies have shown mixed results regarding the predictive validity of the test findings; however, they usually employ only a limited number of tests for prediction representing a limited number of cognitive domains. Using a concurrent validity design, the present study investigated the bivariate associations between various neuropsychological testing domains (i.e. intellectual, academic, language, visuoperceptual, memory, and executive functioning) and level of functioning as indexed by the DRS. Participants were administered the DRS and the neuropsychological evaluation during the initial part of post-acute rehabilitation. Composite scores were derived for each of the neuropsychological domains. Most participants were categorized as sustaining a severe TBI. The mean age and education of this predominately male sample was 28.84 years (SD = 9.13) and 11.83 years (SD = 1.7), respectively. Results revealed a significant positive relationship between performances in intellectual, executive, academic, and visuoperceptual domains and level of functioning.

Canine bronchoconstriction, gas trapping, and hypoxia with methacholine.

The effects of an intravenous methacholine infusion on cardiovascular-pulmonary function were measured in seven mongrel dogs (22.0 +/- 2.8 kg), anesthetized with chloralose and urethan and beta-adrenergically blocked with propranolol. In a volume-displacement plethysmograph, physiological measurements were made at base line and 25 min after establishing a methacholine infusion (0.1-1.0 mg X kg-1 X h-1). Methacholine significantly (P less than 0.05) increased airways resistance (1.9 +/- 0.8 to 8.2 +/- 2.9 cmH2O X l-1 X s), decreased static lung compliance (84.7 +/- 18.5 to 48.2 +/- 9.4 ml/cmH2O), depressed arterial PO2 (81 +/- 17 to 56 +/- 10 Torr), and lowered blood pressure (132 +/- 10 to 69 +/- 18 Torr) and cardiac output (5.7 +/- 1.9 to 4.1 +/- 1.2 l/min). These effects persisted during a further 80 min of methacholine infusion conducted in five of the animals. During the initial 25-min period of methacholine, the end-expired volume (volume-displacement Krogh spirometer) rose in all animals, indicating an increase in functional residual capacity from 997 +/- 115 to 1,623 +/- 259 ml (P less than 0.0005). Analysis of pulmonary pressure-volume curves revealed no change in total lung capacity but an increase in residual volume from 489 +/- 168 to 1,106 +/- 216 ml (P less than 0.001). Thus methacholine caused 617 ml of gas trapping, which was not detected by the Boyle's law principle, presumably because gas was trapped at high transpulmonary pressure. We suggest that intravenous methacholine-induced canine bronchoconstriction, which causes gas trapping and hypoxia, may be a useful animal model of clinical status asthmaticus.

Impact of freestanding emergency centers on hospital emergency department use.

This study was conducted to determine whether hospital emergency department (ED) use has been affected by the presence of freestanding emergency centers (FECs) in hospitals' service areas. A sample of FECs was drawn and hospitals in their service areas identified. ED visits to those hospitals from 1970 to 1980 were compared with those of a comparison group of hospitals not studied. The presence of FECs did not lead to a decline in ED visits to hospitals in their service areas. The study documented that FECs are located near hospitals that are larger than average and that have busier EDs. Because of the relative newness of FEC development, future studies of this type should be conducted. This study could not answer the question of whether FECs caused the growth of hospital ED visits to slow. It did not attempt to measure the impact FECs have on private medical practices or determine whether FECs attract currently underserved patient groups.

Vanadium in photosynthesis of Chlorella fusca and higher plants.

The influence of vanadium compounds (vanadate, vanadyl citrate) on photosynthesis in Chlorella fusca and in algal and spinach chloroplasts has been investigated. It was found that: 1. At moderately high concentrations (at least 0.1 mM) both vanadate and vanadyl citrate enhance photosynthetic O2 production in intact C. fusca cells. At lower V concentration (about 2 microM) only vanadate stimulates photosynthesis. The increase is dependent on culture conditions and on light intensity. 2. Up to 1 mM V, neither vanadium compound influences PS II activity, either in intact cells or in algal or spinach chloroplasts. 3. The PS I reaction in algal and spinach chloroplasts is maximally enhanced (3-fold) in presence of vanadium (20 microM). The increase is independent of light intensity. 4. Cr(VI), Mo(VI), and W(VI) (1 mM) stimulate photosynthesis in intact C. fusca cells, but do not influence the photosystems of isolated chloroplasts. Vanadium is suggested to act as a redox catalyst in the electron transport from PS II to PS I.

Potentiation of endotoxicity by carrageenan.

Carrageenan can potentiate the lethal effects of endotoxin by 100- to more than 3,000-fold.