Bulk phase resource ratio alters carbon steel corrosion rates and endogenously produced extracellular electron transfer mediators in a sulfate-reducing biofilm.

G20 biofilms were cultivated on 316 steel, 1018 steel, or borosilicate glass under steady-state conditions in electron-acceptor limiting (EAL) and electron-donor limiting (EDL) conditions with lactate and sulfate in a defined medium. Increased corrosion was observed on 1018 steel under EDL conditions compared to 316 steel, and biofilms on 1018 carbon steel under the EDL condition had at least twofold higher corrosion rates compared to the EAL condition. Protecting the 1018 metal coupon from biofilm colonization significantly reduced corrosion, suggesting that the corrosion mechanism was enhanced through attachment between the material and the biofilm.

Developing product quality standards for wheelchairs used in less-resourced environments.

Background: Premature failures of wheelchairs in less-resourced environments (LREs) may be because of shortcomings in product regulation and quality standards. The standards published by the International Organization for Standardization (ISO) specify wheelchair tests for durability, safety and performance, but their applicability to products used in the rugged conditions of LREs is unclear. Because of this, wheelchair-related guidelines published by the World Health Organization recommended developing more rigorous durability tests for wheelchairs.

[Maintenance of AAI(R) mode at the time of generator replacement].

Background: In isolated sinus node disease single lead atrial stimulation is recommended. However, an inherent risk includes emerging AV node disturbances with serious bradycardia in the follow-up. This possible scenario frequently results in the implantation of an additional ventricular lead.

Thermodynamic characterization of RNA duplexes containing naturally occurring 1 x 2 nucleotide internal loops.

Thermodynamic data for RNA 1 x 2 nucleotide internal loops are lacking. Thermodynamic data that are available for 1 x 2 loops, however, are for loops that rarely occur in nature. In order to identify the most frequently occurring 1 x 2 nucleotide internal loops, a database of 955 RNA secondary structures was compiled and searched.

Cathepsin L expression is directed to secretory vesicles for enkephalin neuropeptide biosynthesis and secretion.

Proteases within secretory vesicles are required for conversion of neuropeptide precursors into active peptide neurotransmitters and hormones. This study demonstrates the novel cellular role of the cysteine protease cathepsin L for producing the (Met)enkephalin peptide neurotransmitter from proenkephalin (PE) in the regulated secretory pathway of neuroendocrine PC12 cells. These findings were achieved by coexpression of PE and cathepsin L cDNAs in PC12 cells with analyses of PE-derived peptide products.

Distinct factors correlating with adverse cardiac events after major vascular surgery.

Introduction: Cardiovascular complications remain the principal cause of both morbidity and mortality after major vascular surgery. The well-known coincidence between vascular disease and coronary artery disease provided the rationale for a detailed analysis of major perioperative cardiovascular complications in their relation to preoperative and intraoperative parameter

Methods And Patients: 90 patients scheduled to undergo either femoral-popliteal bypass (n = 74) or repair of an infrarenal aortic aneurysm (n = 16) were prospectively included in the study. All patients had no signs of unstable cardiac disease and required no cardiac testing.

The value of permanent follow-up of implantable pacemakers--first results of an European trial.

A clinical study investigates the use of Home Monitoring (HM) in pacemaker therapy. For 3 months patients are supervised by daily automatic HM messages. Endpoints are the technical feasibility and the clinical benefit of HM.

Activation-induced peripheral blood T cell apoptosis is Fas independent in HIV-infected individuals.

T cell apoptosis has been proposed as an important contributor to the functional defects and depletion of T cells in HIV-infected individuals. However, the mechanisms involved in this apoptosis have not been elucidated. We recently showed that peripheral blood T cells from HIV-infected individuals are especially susceptible to Fas antigen-induced apoptosis.

Fas antigen stimulation induces marked apoptosis of T lymphocytes in human immunodeficiency virus-infected individuals.

Apoptosis (programmed cell death) of T lymphocytes has been proposed as a mechanism which plays an important role in the pathogenesis of human immunodeficiency virus (HIV) disease. Activation of Fas (CD95) can either result in costimulation of proliferation and cytokine production or in the induction of apoptosis of T lymphocytes. This raises the possibility that Fas is involved in the observed T cell apoptosis during HIV disease.

A nebulizer system for highly reproducible aerosol delivery.

The output characteristics of current nebulizer systems are influenced by factors such as inspiratory flow, temperature and relative humidity of the ambient air as well as surface tension of the nebulizing solutions. Due to the resulting alteration of droplet characteristics the delivery of aerosolized drugs is variable. A nebulizer system, the PARI IS-2, has been designed for the delivery of aerosolized potent drugs.

Right ventricular conductance to establish closed-loop pacing.

Innovations in pacing technology, which include the addition of rate-responsive features to programmable pacemakers, can improve the quality of life of patients suffering from sick sinus syndrome. Among the strategies providing rate-adaptive cardiac pacing, the most attractive is the physiological restoration of closed-loop chronotropic control. This paper describes how autonomic nervous system (ANS) control information is extracted from dynamic measures of myocardial contractile performance obtained from unipolar conductance measurements using the stimulation electrode in the right ventricular cavity.

[Dilated myocardial disease as sequela of chronic Lyme carditis].

A report is given on a 39-year-old man, who developed, after a tick bite, erythema, progressing symptoms and, after 3 years, showed the typical clinical and echocardiographic signs of a dilative cardiomyopathy. A serological test for Lyme Borreliosis was positive. Most of the symptoms disappeared after high-dose penicillin therapy.

Isolation of Legionella pneumophila serogroup 3 from pericardial fluid in a case of pericarditis.

A 43-year-old woman was hospitalized for fulminant pericarditis. During diagnostic work-up, an as yet unknown bronchial carcinoma was detected. In the pericardial exudate Legionella pneumophila serogroup 3 was demonstrated by direct fluorescent antibody technique and by culture.

[Intracardiac recording of potentials in placing a thermodilution catheter].

It is reported on methods of positioning our former described flow directed thermodilution (TD) catheter by the intracardiac ECG derived from two electrodes, one at the tip of the catheter near the temperature sensor and the other six centimeter proximally of it. The typical criterion of the intracardiac ECG in the outflow tract of the right ventricle and in the pulmonary artery are listed, especially the amplitudes, the QRS-splits, T-wave inversion and P-wave configuration.

[Lyme borreliosis--a possible cause of atrioventricular block].

Eight cases of Lyme borreliosis of clinical certainty with carditis are reported. In six patients, AV-blocks were predominant, two patients had a myopericarditis. Six acute cases were seropositive, but one case remained seronegative.

[Physiologic frequency adaptation of cardiac pacemakers using systolic time intervals].

Of the parameters in consideration for control of physiological rate responsive pacing special interest is directed to stroke volume. In search of indirect parameters which are correlated to stroke volume it is demonstrated on principle that systolic time intervals could be used. From the relation ejection time versus pre-ejection time (LVET/PEP) which is known for its correlation to stroke volume a simple algorithm is derived which is based on the realization that PEP is related to the reciprocal of cardiac output.

[A new catheter for hemodynamic studies].

It is reported on a new catheter technique for the determination of the cardiac output by means of the method of thermodilution. It consists of a thin sensorcatheter (3 Ch), which contains a microthermistor as temperature sensor and additionally two electrodes. The insertion of the catheter is carried out via puncture of the subclavian vein by means of a special introducer set, the outer sheath of which can used for injecting the cold solution.

[Possibilities for frequency adjusted heart stimulation].

In the sick sinus syndrome, in sinu-atrial conduction defects or in atrial flutter or fibrillation a stress-adapted, frequency-adapted stimulation cannot be obtained by the processing of the atrial potential. Here one depends on partly extracardiac parameters which contain informations about the metabolic and stress situation, respectively. A survey of the parameters for a frequency-adapted stimulation discussed at present is given and a critical valuation of them is carried out.

[Insertion behavior of miniature IBW-79 pressure transducers in the left heart].

It is reported on the properties of the new catheter-tip pressure transducer IBW-79 (Ch 5) for applications in the left heart. The approach to the left ventricle was carried out with the help of Seldinger-technique (Ch 10) via A. femoralis.