Flow analysis of the Cleveland Clinic centrifugal pump.

An implantable ventricular assist blood pump is being developed by the Cleveland Clinic Foundation in cooperation with the NASA Lewis Research Center. At the nominal design condition, the pump provides blood flow at the rate of 5 L/min at a pressure rise of 100 mmHg and a rotation speed of 3000 RPM. Bench testing of the centrifugal pump in a water/glycerin mixture has provided flow and pressure data at several rotative speeds. A one-dimensional empirically based pump flow analysis computer code developed at NASA Lewis Research Center has been used in the design process to simulate the flow in the primary radial pump stage. The computer model was used to size key impeller and volute geometric parameters that influence pressure rise and flow. Input requirements to the computer model include a simple representation of the pump geometry. The model estimates the flow conditions under design and off-design operating conditions at the impeller leading and trailing edges, and the volute inlet and exit. Output from the computer model is compared to flow and pressure data obtained from bench testing.

Hungarian multicentre epidemiologic study of the warning and initial symptoms (prodrome, aura) of epileptic seizures.

We carried out a Hungarian multicentre study to assess the frequency of the occurrence of warning symptoms preceding epileptic seizure. The data of 562 patients with epilepsy out of a total of 1124 were analysed on the basis of questionnaires filled in under standard conditions. About 50% of the patients experienced warning symptoms before a smaller or greater part of their seizures. Their appearance was fairly consistent and became mainly manifested in the form of headache, epigastric sensation and dysphoria. In relation to epileptological basic data, it was found that warning symptoms appeared primarily in focal epilepsies and among them they mainly preceded generalized tonic clonic and complex partial seizures. Between the warning symptom and the onset of the seizure there was usually a longer interval during which (and generally also during the warning symptom) the patient remained able to act. About 20% of the patients enrolled in the study tried to inhibit the onset or mitigate the course of the seizure and about 10% judged their spontaneous activity carried out in that direction to be successful. The frequency of the occurrence of independent prognostic symptoms not followed by a seizure was relatively low, and among epileptics with warning symptoms the incidence of seizures occurring without a preceding event was not high either. Based on our experiences, we have drawn the conclusion that, in a significant part of epileptic patients, the warning symptoms render possible the supplementation of the therapy by the development of seizure-inhibiting or seizure-avoiding behaviour or activity.

Assessing the sedative (adverse) effects of antiallergic drugs by quantitative electroencephalography: effects of setastine a non-sedating antihistaminic drug.

In order to assess the effects of Loderix (setastine) on the EEG ten healthy male volunteers were investigated in double-blind, placebo-controlled, cross-over arrangement. In addition to the test compound (Loderix) volunteers were treated with vehicle and with two referent drugs (terfenadine, Teldane, and chloropyramine HCl, Suprastin) possessing sedative effects of very different degrees. The different effects of the referent drugs on the central nervous system (CNS) were precisely indicated by the posterior alpha/theta ratio in the EEG. This marker parameter was affected by Loderix in the same direction as by Teldane and in the opposite direction as compared to Suprastin. In addition, Loderix increased the beta frequency range in the median areas of both hemispheres, moreover, it increased the total EEG power. The latter changes raise the question if Loderix has an "own" action on the EEG. (The observed "own" effect could not even be brought into connection with decrease of the vigilance level). The results strengthen the view that the action of Loderix on the EEG is similar to that of induced by Teldane, a drug very favourable in respect of the sedative side effects. Moreover, the drug did not affect the EEG power spectra in a direction that referred to sedative action. The spectral parameters in the "pharmaco" EEG recordings seem to be useful in the objective definition of the central (psychotropic) side-effects of drugs. This is a methodical achievement of the present study.

Correlations between night sleep duration and seizure frequency in temporal lobe epilepsy.

Correlations between occurrence of complex partial seizures and altered sleep duration were analyzed in a small but strongly homogeneous population of temporal lobe epilepsy patients. Sleep deprivation and oversleep were determined individually; 682 epileptic seizures occurring on 4,995 days were related to occasional alterations of night sleep duration. The seizure-inducing effect of an actual relative sleep deprivation was 67-100% in four cases and 49-64% in four cases. Oversleep had no consistent seizure-provoking effect. Relative sleep deprivation may have a seizure-provoking effect, especially in temporal lobe epilepsy. This information may be used to instruct epileptic patients concerning sleep hygiene which might improve the efficacy of antiepileptic drug (AED) treatment, even if no change is made in medication.

Place of phenytoin in treatment of resistant epilepsy.

A retrospective therapeutical follow-up of 64 therapy-resistant epileptics treated by phenitoin (DPH) is made chronically. In the study 232 treatment periods of at least two years' duration were analyzed. Distribution of DPH therapeutic combinations was evaluated according to the type of epilepsy, seizure form, seizure frequency, elements of patient compliance, and results of serum level measurements. According to the author's opinions DPH is still one of the most effective agents in the treatment of resistant epilepsy, but in most cases as a constant component of antiepileptic bitherapy. Its pharmacokinetic features and optimal dosage show great individual variability, larger than that of other drugs and, in cases of combined drug regimens, interactions may more frequently be expected.

Life events and seizure frequency in epileptics: a follow-up study.

On the basis of 2227 examinations of 272 epileptic patients the connection between the seizure frequency and life events of negative or positive emotional nature was analysed. Negative life events went with a deterioration, positive factors with a decrease of seizure frequency in most cases. Results of antiepileptic serum measurements suggest that emotional factors exert their effect by influencing the patient's compliance. Supposed intrapsychic patho-mechanisms of this connection are briefly discussed. Authors' results stress the importance of psychic care of epileptics simultaneously with medical treatment.

Ability of deutan color defectives to perform simulated air traffic control tasks.

Air traffic controllers perform a variety of tasks which require them to identify, discriminate, and name colors. Qualification standards for this occupation require applicants and incumbents to have normal color vision. The validity of this standard has been questioned and is currently under review. In this study, 22 deutans and 78 normals were tested on a set of tasks which simulated critical tasks performed daily by air traffic controllers. The four tasks included discriminating red from black pencil marks on flight progress strips, color-naming of 1 degree and 0.1 degree discs, and identification of colored line segments embedded in a multicolored background. Deutans classified as mild were found to perform all tasks as well as normals. Moderate deutans performed only the large disc color-naming task as well as normals, whereas severe deutans performed none of the tasks as well as normals. Different methods for scoring the color vision tests were explored to determine their value as predictors of task performance. The D-15 relative error score was found to be the single best predictor of performance on the tasks (r-square = 0.602). It is concluded that mild deutan color defectives have adequate color vision for safe performance of several critical air traffic control tasks. Moderate and severe deutans do not. In addition, the results of several methods for scoring color vision tests can be used to predict group, but not individual, performance with high reliability.

Adverse tax rulings affect exemptions for clergy and religious.

Recent court cases illustrate the federal government's changing position toward automatic tax exemptions for members of religious institutes who are employed outside their institute. Before 1977, the IRS seemed inclined to assume that members acted as agents for their institute and that their income would not be taxable. In Fogarty v. U.S. the court ruled that a priest's income from a university teaching position was taxable because he was not acting as an agent for the Jesuits. In Schuster v. Commissioner, the court held for the government, stating that the "triangle relationship" among employee, outside third-party employer, and principal/religious institute was insufficient to warrant the necessary agency relationships. Samson v. U.S. questioned whether Sr. Mary K. Samson's county hospital work constituted "employment" for FICA tax purposes. The court concluded the tax was assessable on her wages because she was a county employee. It denied a rehearing after a dissenting judge concluded that past rulings were inconsistent and had little bearing on FICA taxation. The legal view of religious tax exemption is much narrower than 10 years ago. Catholic institutes must closely analyze the relationship between their members and outside third-party employers to avoid taxation. They must legally assert their control over their members' actions before the employment is in effect.

The ability of protan color defectives to perform color-dependent air traffic control tasks.

Air traffic controllers perform a variety of tasks which require them to identify, discriminate and name colors. Qualification standards for this occupation require applicants to have normal color vision. Although the validity of this standard has been questioned, Adams and Tague recently presented evidence in this Journal (1985;62:744-50) that protanopes cannot perform color-dependent air traffic control tasks reliably. In our study, the results of 7 severe and 2 moderate protans are compared to those of 78 normals on a set of tasks which simulated critical tasks performed daily by air traffic controllers. The four tasks included discriminating red from black pencil marks on flight progress strips, color-naming of 1(0) and 0.1(0) discs, and identification of colored line segments embedded in a multi-colored background. The severe protans we tested performed none of the tasks as well as normals. While the performance of the moderate protans was better, statistical conclusions could not be drawn. Our set of tasks bears many similarities to the set used by Adams and Tague and it appears we were trying to answer the same questions. The results of the two studies are similar and the conclusions are the same: severe protans cannot perform color-dependent air traffic control tasks reliably.

Natural antibodies in healthy adults.

The serum of 100 adults living in Budapest was examined for isohaemagglutinin titre with haemaglutination, for staphylococcal-antitoxin titre with haemolysis inhibition and for bacterial antibody titre against 17 different groups of bacteria with passive haemagglutination. Antibody levels in males, except for certain bacterial antibodies, were somewhat lower than in females. The antibody titres, especially in men, decreased gradually from 20 to 50 years of age and were usually lower in Rh negative than in Rh positive persons.

Determination of the molecular weight of IgM by thin-layer chromatography combined with immunodiffusion in normal and pathological conditions.

An immunodiffusion method combined with thin-layer chromathography was elaborated for the assessment of the molecular weight of IgM. Sera from 100 normal individuals as well as from 162 patients with different types of paraproteinaemia, 100 patients with uveitis and 55 venous umbilical cord sera were analysed. Presence of 75 IgM, besides the usual 19S IgM was detected in 21% of the normal sera, in 27% of the paraproteinaemic sera, in 30% of the uveitic sera and in 5.4% of venous umbilical cord sera. IgM level in the sera was determined by radial immunodiffusion. The authors didn't find correlation between the presence of 7S IgM and different levels of IgM.