Test Controller Design, Implementation, and Performance for a Magnetic Suspension Continuous Flow Ventricular Assist Device

A new continuous flow ventricular assist device using full magnetic suspension has been designed, constructed, and tested. The magnetic suspension centers the centrifugal pump impeller within the clearance passages in the pump, thus avoiding any form of contact. The noncontact operation is designed to give very high expected mechanical reliability, large clearances, low hemolysis, and a relatively small size compared to current pulsatile devices. A unique configuration of magnetic actuators on the inlet side and exit sides of the impeller provides full 5 axis control and suspension of the impeller. The bearing system is divided into segments which allow for 3 displacement axes and 2 angular control axes. The controller chosen for the first suspension tests consists of a decentralized set of 5 proportional integral derivative (PID) controllers. This document describes both the controller and an overview of some results pertaining to the magnetic bearing performance. The pump has been successfully operated in both water and blood under design conditions suitable for use as a ventricular assist device.     

The speech evoked potential in normal subjects and patients with cerebral hemispheric lesions

The present study deals with observations on the “speech evoked potential”-a late positive potential evoked by word repetition. These potentials, evoked by “silent” repetition of polysyllabic words, were averaged and recorded from the scalp overlying the inferior frontal regions on both sides in 20 normal healthy subjects of ages ranging from 13–58 years. The potential had a triphasic negative, positive, negative morphology and was present over both hemispheres in left as well as right handed subjects. The main positive deflection and mean latencies of 219.2 msec and 221.6 msec and mean amplitude of 6.2 μv and 6.5 μv respectively on the left and right sides. Though there were interindividual variations in latency, amplitude and morphology, there was a high degree of intraindividual similarity and reproducibility in subjects. The variations in these parameters with age, sex and handedness are discussed. In 10 patients with cerebral lesions, the evoked potential was normal in 5 cases with right frontal lesions and showed abnormalities in 3 of 5 cases with left frontal lesions. The speech evoked potential may be useful in the further study of electrical correlates of speech output in speech disorders.     

Mast cell in leprosy

Mast cell distribution in the affected skin and in the apparently normal skin at least 10 cm away from the lesion was studied in 250 leprosy patients. These cells were found and were more numerous in the apparently normal skin of established cases of leprosy as well amongst indeterminate group. Absence of mast cells was conspicuous in 16.7% LL, 41.7% BB, 40.9% BT, and 68.0% TT lesions. It is suggested that mast cells might play a role in the early stages of the disease and in postreactional connective tissue proliferation.     

Comparison over short term of mortality and morbidity of mechanical and bioprosthetic heart valves in the Indian population

Background  

Choice of heart valve in the developing countries is an unsettled issue due to illiteracy and noncompliance related increase in incidences of stuck valve and anticoagulant related bleeding and as such international guidelines may not be wholly applicable. The aim of our study was to compare outcomes after mitral, aortic or double valve replacements with mechanical versus bioprosthetic valves.     

PAMPA permeability, plasma protein binding, blood partition, pharmacokinetics and metabolism of formononetin, a methoxylated isoflavone

Formononetin (FMN) is a methoxylated isoflavone which is the major constituent in red clover and in commercially available extracts of this plant. In this study, we investigated the parallel artificial membrane permeability assay (PAMPA) permeability, protein binding, blood uptake characteristics, pharmacokinetics and metabolism of FMN. The permeability study samples were analyzed by HPLC-PDA method; whereas the pharmacokinetic study, protein binding and whole blood partitioning samples were analyzed by LC-MS/MS method. The PAMPA permeability of FMN was found to be high at pH 4.0 and 7.0. Plasma protein binding of FMN was found to be 93.61 ± 0.44% and 96.14 ± 0.15% at the tested concentration of 50 and 150 ng/mL, respectively. FMN reached equilibrium fast between red blood cells (RBCs) and plasma, and the partition coefficients between RBCs and plasma (K_RBC/PL) were independent of the initial rat blood concentrations of FMN. The bioavailability of unchanged/free FMN was found to be poor, i.e. approximately 3%. FMN was found to have a high clearance (5.13 L/h/kg) and a large apparent volume of distribution (14.16 L/kg). Circulating conjugates (glucuronides/sulfates) of FMN and daidzein (DZN) were quantified using enzymatic hydrolysis of plasma samples. The levels of isoflavone glucuronides/sulfates were found to be much greater than that of the corresponding aglycones.     

Relook TURBT in superficial bladder cancer: its importance and its correlation with the tumor ploidy

ObjectiveTo evaluate various prognostic factor predictors of residual growth in Relook transurethral resection of bladder tumor (TURBT) in superficial bladder cancer. Also, to evaluate the role of Relook TURBT along with the ploidy for prediction of recurrence and stage progression in these patients.Material and MethodsFifty patients with superficial bladder cancer underwent TURBT after complete evaluation. Ploidy of the tumor specimen was evaluated by flow cytometry. After 4 to 6 weeks of initial TURBT, these patients underwent Relook TURBT. Final treatment was given after the results of the histological evaluation of these specimens. Patients who underwent bladder sparing treatment were followed-up.ResultsOf the patients, 28.5% had residual tumor in Relook TURBT. Growth was found to be at the same site in 66.7% and at a different site 33.3%; 75% had single while 25% had multiple residual growth. Residual malignant tissue had a statistically significant correlation with size of the tumor (>3 cm), appearance (solid tumor), number (>3), grade (high), and multiple previous resections. Overall, the up-migration of stage and grade leads to change in treatment in 41.6%; 5 underwent radical cystectomy and 1 opted for radiotherapy; in 2 patients, intravesical BCG was given. In follow-up of mean 11.5 months, 16.6% had recurrence. Presence of residual growth in Relook TURBT along with number, size, morphology, and multiple previous resections were found to have significant correlation with the recurrence in these patients. Ploidy and grade of the tumor were not found to have correlation.ConclusionsMultiple, more than 3 cm, solid high grade tumor with > 3 previous resections were predictors of presence of residual tumor in Relook TURBT. Presence of residual growth is a significant risk factor for recurrence. Ploidy was not found to be significantly correlated with recurrence.     

Etomidate, propofol and the neurosteroid THDOC increase the GABA efficacy of recombinant alpha4beta3delta and alpha4beta3 GABA A receptors expressed in HEK cells

General anesthetics, once thought to exert their effects through non-specific membrane effects, have highly specific ion channel targets that can silence neuronal populations in the nervous system, thereby causing unconsciousness and immobility, characteristic of general anesthesia. Inhibitory GABA_A receptors (GABA_ARs), particularly highly GABA-sensitive extrasynaptic receptor subtypes that give rise to sustained inhibitory currents, are uniquely sensitive to GABA_AR-active anesthetics. A prominent population of extrasynaptic GABA_ARs is made up of α4, β2 or β3, and δ subunits. Considering the demonstrated importance of GABA receptor β3 subunits for in vivo anesthetic effects of etomidate and propofol, we decided to investigate the effects of GABA anesthetics on “extrasynaptic” α4β3δ and also binary α4β3 receptors expressed in human embryonic kidney (HEK) cells. Consistent with previous work on similar receptor subtypes we show that maximal GABA currents through “extrasynaptic” α4β3δ receptors, receptors defined by sensitivity to EtOH (30 mM) and the β-carboline β-CCE (1 μM), are enhanced by the GABA_AR-active anesthetics etomidate, propofol, and the neurosteroid anesthetic THDOC. Furthermore, we show that receptors formed by α4β3 subunits alone also show high GABA sensitivity and that saturating GABA responses of α4β3 receptors are increased to the same extent by etomidate, propofol, and THDOC as are α4β3δ receptors. Therefore, both α4β3 and α4β3δ receptors show low GABA efficacy, and GABA is also a partial agonist on certain binary αβ receptor subtypes. Increasing GABA efficacy on α4/6β3δ and α4β3 receptors is likely to make an important contribution to the anesthetic effects of etomidate, propofol and the neurosteroid THDOC.