Progress on development of the Nimbus-University of Pittsburgh axial flow left ventricular assist system

Nimbus Inc. (Rancho Cordova, CA) and the University of Pittsburgh have completed the second year of development of a totally implanted axial flow blood pump under the National Institutes of Health Innovative Ventricular Assist System Program. The focus this year has been on completing pump hydraulic development and addressing the development of the other key system components. Having demonstrated satisfactory pump hydraulic and biocompatibility performance, pump development has focused on design features that improve pump manufacturability. A controller featuring full redundancy has been designed and is in the breadboard test phase. Initial printed circuit layout of this circuit has shown it to be appropriately sized at 5 x 6 cm to be compatible with implantation. A completely implantable system requires the use of a transcutaneous energy transformer system (TETS) and a diagnostic telemetry system. The TETS power circuitry has been redesigned incorporating an improved, more reliable operating topography. A telemetry circuit is undergoing characterization testing. Closed loop speed control algorithms are being tested in vitro and in vivo with good success. Eleven in vivo tests were conducted with durations from 1 to 195 days. Endurance pumps have passed the 6 month interval with minimal bearing wear. All aspects of the program continue to function under formal quality assurance.     

Benefits of high-dose i.v. immunoglobulin in patients with severe steroid-dependent asthma

STUDY OBJECTIVE: To determine the efficacy of IV immunoglobulin (IVIg) in severe asthma to reduce steroid requirements. DESIGN: Pre- and posttreatment measurements were analyzed using Dunnett's multiple comparison procedure. SETTING: Hospital clinical research center. PATIENTS: Eleven adolescents and adults with severe, steroid-dependent asthma enrolled over a 14-month period. INTERVENTIONS: IVIg was administered at a dose of 2 g/kg every 4 weeks for a total of seven infusions. MEASUREMENTS AND RESULTS: Steroid requirements, pulmonary function including lung volumes, symptom scores, bone densitometry, and airway reactivity monitored by methacholine challenge were followed over the course of 7 months. A significant decrease in steroid usage was achieved. Despite substantial steroid reduction, the patients demonstrated improvement in their pulmonary function and symptom scores. The responses to methacholine challenge were unaffected by IVIg treatment. CONCLUSIONS: IVIg provides a potentially important adjunctive therapy in severe asthma, reducing oral steroid requirements and steroid side effects without deterioration of lung function.     

Coronary surgery on the beating heart under extracorporeal circulation in high-risk patients. An acceptable compromise?

Coronary artery surgery with cardioplegia in high risk patients carries a risk of myocardial ischaemia and, without cardiopulmonary bypass, is not always technically feasible. The authors assessed an alternative, surgery on the beating heart with haemodynamic assist by cardiopulmonary bypass in 43 consecutive patients with poor left ventricular function (mean ejection fraction: 0.26), evolving myocardial ischaemia or acute myocardial infarction, old age (mean: 79.5 years) and comorbid conditions. Results were assessed mainly on clinical criteria. In addition, 9 patients had pre- and post-cardiopulmonary bypass measurements of markers of myocardial ischaemia (troponine Ic) and systemic inflammation (interleukines 6 and 10, elastase). In 6 cases, right atrial biopsy was analysed for expression of messenger ribonucleic acid coding for heat shock protein (HSP) 70; the data were compared with those of patients operated under warm blood cardioplegia. There was one cardiac death and one myocardial infarction. Myocardial conservation was confirmed by the minimal increase in troponine Ic levels and the significant increase in HSP 70 in RNA suggesting myocardial adaptation to stress. On the other hand, the minimal concentrations of mediators of inflammation were not significantly changed. In selected high risk patients, coronary revascularisation on the beating heart under cardiopulmonary bypass could be a valuable alternative. It conserves the potentially deleterious effects of cardiopulmonary bypass but peroperative global myocardial ischaemia, an important factor in the aggressivity of cardiac surgery, is eliminated.     

Liver disease in polyglandular autoimmune disease type one: clinicopathologic study of three patients and review of the literature

We report the findings from liver biopsies of three patients with polyglandular autoimmune disease type 1. The livers in two patients had histologic features of chronic hepatitis that eventuated in bridging fibrosis and cirrhosis over a period of several years. Nonspecific lobular and portal tract inflammation was present in the liver biopsy of the third patient. Although these patients did not have liver-specific autoantibodies, the liver disease in polyglandular autoimmune disease type 1 possibly represents an expression of autoimmune hepatitis.     

High-performance concrete with recycled stone slurry

Presently large amounts of slurry are generated in natural stone processing plants with an important impact on the environment and humans. This paper describes this impact and presents test results showing the feasibility of using this industrial by-product in high-performance concrete production as a substitute of fine aggregates. Test results show that this industrial by-product is capable of improving hardened concrete performance up to 16%, enhancing fresh concrete behaviour and can be used in architectural concrete mixtures containing white cement.     

The action of anabolic steroids on bone in experimental animals

Anabolic steroids are currently used in the treatment of established osteoporosis. It has been demonstrated that, at least partly, anabolic steroids increase bone density by stimulating bone formation. Very little is known about how anabolic steroids affect bone in experimental animals. Because bone studies in animals have been performed only with the anabolic steroid nandrolone, or its long-acting ester nandrolone decanoate (ND), we present a general overview in this paper of the effect of these anabolic agents in various steroid-affected animal models for osteoporosis, viz. gonadectomized rats, heparin-treated mice and intact or ovariectomized dogs. In rats and mice these agents increase longitudinal and periosteal bone growth and bone mass, thus demonstrating their anabolic action. They also decrease trabecular bone resorption in ovariectomized and orchidectomized rats, which indicates that they have anti-catabolic effects. In ovariectomized rats, ND was found to increase the mechanical strength of cortical bone, which is an important property in a drug that is intended to be used in treating established osteoporosis. In elderly dogs, ND was found to stimulate endosteal bone formation. These findings indicate that nandrolone and ND have beneficial effects on bone in both oestrogen and androgen-deficient animals.     

Qualitative and quantitative assessment of exposure to geomagnetic field variations on the functional status of the human brain

The comparison of functional dynamics of human brain with reference to qualitative and quantitative characteristics of local geomagnetic field (GMF) variations was conducted. It was showed that just local GMF variations can be a principal reason of modulation the human brain's functional state. The steady and unsteady states of human brain can be determined: by geomagnetic disturbances before the observation period; by structure and doses of GMF variations; by different combinations of qualitative and quantitative characteristics of GMF variations. The optimal level of GMF activity, manifested in periodic oscillations in certain amplitude-frequency range is demanded for steady brain's functional state. The decrease of optimal GMF activity level and the appearance of aperiodic disturbances of GMF can be a reason of unsteady brain's state.