Surface pretreatments for medical application of adhesion.

Medical implants and prostheses (artificial hips, tendono- and ligament plasties) usually are multi-component systems that may be machined from one of three material classes: metals, plastics and ceramics. Typically, the body-sided bonding element is bone. The purpose of this contribution is to describe developments carried out to optimize the techniques, connecting prosthesis to bone, to be joined by an adhesive bone cement at their interface.

Research methodology.

Research aims to reach valid conclusions through scientific enquiry. Valid conclusions can only be reached if bias is minimized or eliminated. Bias can potentially take place in the design, implementation, or analysis of a study.

Spins swing like pendulums do: an exact classical model for TOCSY transfer in systems of three isotropically coupled spins 1/2.

An exact correspondence is found between the quantum dynamics of three isotropically coupled spins 1/2 and the dynamics of three coupled classical oscillators. This correspondence is demonstrated by experimentally simulating the polarization transfer functions of an isotropic mixing TOCSY experiment with a set of mechanically coupled pendulums. The extend to which the exact correspondence holds is analyzed and it is shown that it breaks down for systems consisting of more than three coupled spins.

Beliefs and attitudes of members of the American Academy of Orthopaedic Surgeons regarding the treatment of anterior cruciate ligament injury.

Purpose: The purpose of the study was to quantify the amount of agreement among orthopaedic surgeons regarding the natural history of the anterior cruciate ligament (ACL)-deficient knee, surgery, and rehabilitation, and the treatment of these patients.

Type Of Study: Physician mail survey.

Methods: Orthopaedic surgeons were randomly selected from the American Academy of Orthopaedic Surgeons (AAOS) directory.

Minimally invasive coronary artery bypass grafting in high-risk patients. Late follow-up with assessment of left internal mammary artery graft patency and flow by exercise transthoracic Doppler echocardiography.

Unlabelled: Patients with significant risk factors are at increased risk of higher mortality and morbidity (9-16%) after CABG-procedures with cardiopulmonary bypass (CPB). When catheter interventions are not applicable and conventional CABG with CPB are considered to have an unacceptable perioperative risk, these patients (n=35) were scheduled for minimally invasive coronary artery bypass grafting (MIDCAB).

Patients And Methods: The risks leading to exclusion of conventional CABG procedures were: extremely impaired LV-function (EF<20%), severe pulmonary diseases, malignant carcinoma, compromised coagulation system, age >80 years with impaired physical constitution, redo-procedures after complicated initial operation, symptomatic descending thoracic aortic aneurysm, ongoing long-term intensive care treatment with unclear prognosis.

A comparison of two time intervals for test-retest reliability of health status instruments.

Studies of test-retest reliability for health-related quality of life instruments have used varying intervals between test administrations. There is no evidence available to aid in the selection of the time interval between questionnaire administrations for a study of test-retest reliability for health status instruments. We compared the test-retest reliability at 2 days and 2 weeks for four knee-rating scales and the eight domains of the SF-36.

Suppression of subcritical crack growth in a leucite-reinforced dental glass by ion exchange.

Glass-ceramic materials are frequently used in prosthetic dentistry because of their excellent esthetics. Problematic aspects of glass ceramics are their limited strength, the scatter in their strength data, and their time-dependent strength decrease due to subcritical crack growth effects. The short-term strength level can be significantly increased by an ion-exchange process in a potassium salt.

[A new coating method for cemented femur shaft implants--biocompatibility, stability during sterlization and adhesive strength].

The main cause of aseptic loosening of cemented stems in total hip arthroplasty is the hydrolytic degradation of the metal-cement interface. In order to prevent this debonding a new multilayer method of coating the implant surface involving the use of a silica-/silane technique to create a durable adhesive bond between metal stem and bone cement has been developed. The biocompatibility of all the elements of the multilayer system was confirmed using a human osteoblast cell culture test.

Central circuitry in the jellyfish Aglantha digitale IV. Pathways coordinating feeding behaviour.

The hydromedusan jellyfish Aglantha digitale feeds on small planktonic organisms carried to the margin by tentacle flexions. During feeding, the manubrium bends across ("points") and seizes the prey with flared lips. In immobilized preparations, pointing to a source of electrical stimulation was accurate, 70% of the time, to within 15 degrees.

[A new method to optimize the adhesion between bone cement and acetabular bone in total hip arthroplasty].

Aim: In cemented total hip arthroplasty cup loosening occurs earlier than stem loosening in most of the cases. This is mainly caused by the lack of stabile adhesion between the hydrophobic bone cement and the hydrophilic bone surface of the acetabulum. The aim of this study was to develop a multilayer amphiphilic bonding system which prevents the hydrolytic debonding at the bone cement-bone interface, thus optimizing the compound stability.

Recurrent syncope in a young patient with long QT syndrome: possible relationship of atrioventricular nodal re-entrant tachycardia with neurally mediated spells?

This is a case of a 15-year-old woman with long QT syndrome (LQTS) and a history of 14 events of syncope, demonstrating that the underlying mechanism for any symptomatic episode is not necessarily based on torsades de pointes. The need for careful distinction between true ventricular tachyarrhythmia and other forms of supraventricular tachycardia in the LQTS is the subject of the article. To the knowledge of the authors, this is the first reported case of an association of LQTS with AV nodal re-entrant tachycardia.

Lifetime prediction of all-ceramic bridges by computational methods.

There has been limited use of ceramic materials for all-ceramic posterior bridges. Major reasons are the low strength, the strength scatter, and the time-dependent strength decrease of ceramics due to slow crack growth. The objective of this study was to predict the long-term failure probability and loading capability of all-ceramic bridges (Empress 1, Empress 2, In-Ceram Alumina, and ZrO(2)) by computational techniques.

[Catheter ablation of ectopic atrial tachycardia by electrical pulmonary vein disconnection].

We report a 25-year-old female patient with a long history of symptomatic paroxysmal supraventricular tachycardia. Electroanatomic activation mapping demonstrated a focal tachycardia originating in the right upper pulmonary vein, 3 cm distal to the ostium. Due to the recent experiences in the management of focal atrial fibrillation with catheter ablation, direct ablation applied inside the pulmonary vein was avoided.

[Alterations of left ventricular systolic and diastolic function in pregnant women with insulin-dependent diabetes mellitus].

Background: During pregnancy, major cardiovascular changes occur. The aim of the following study was to investigate the course of hemodynamic parameters under the increased volume load during pregnancy and delivery in women with insulin-dependent diabetes mellitus.

Methods: We examined 51 pregnant diabetic and 51 healthy pregnant women.

Elimination of low-quality ceramic posts by proof testing.

Objectives: Prosthetic posts made of zirconia ceramics are beneficial because of their esthetic advantages. The mechanical reliability of ceramic posts is limited because of the strength level and the large scatter in strength of ceramic materials. The hypothesis of this study is that the failure of ceramic posts in vivo, which occur on low-quality posts because of critical microscopic defects can be excluded using the so-called proof test technology.

A novel aid to elevation of the sinus membrane for the sinus lift procedure.

A maxillary sinus augmentation graft floor can increase vertical bone height for implant placement in patients with a pneumatized sinus. A simple technique can make this routine procedure even more predictable. After the sinus membrane has been adequately reflected, a cottonoid soaked with 1 carpule of 2% Lidocaine with 1:100,000 epinephrine and left in place for 5 to 15 minutes in each maxillary sinus can help create vasoconstriction and hemostasis.

Meniscus repair: considerations in treatment and update of clinical results.

The meniscus plays an important role in the function of the knee. Preservation of the meniscus is preferred if possible when considering treatment of a meniscus tear. A thorough understanding of the anatomy of the meniscus, the structure, the mechanics, and other factors of meniscal healing are critical when evaluating the torn meniscus for a reparative procedure.

Severely resorbed mandible: predictable reconstruction with soft tissue matrix expansion (tent pole) grafts.

Purpose: Attempts to reconstruct the severely resorbed mandible (
Material And Methods: A novel surgical approach using dental implants as "tent poles," along with bone grafting, is described, and the long-term follow-up of 64 cases is presented.

R-curve behavior of dental ceramic materials.

Some technical ceramics exhibit the R-curve effect, i.e., an increasing fracture resistance with crack extension which is a desirable material property because more energy is necessary to propagate a microscopic crack.

C/T polymorphism of the intercellular adhesion molecule-1 gene (exon 6, codon 469). A risk factor for coronary heart disease and myocardial infarction.

Background: The intercellular adhesion molecule-1 (ICAM-1) mediates the interaction of activated endothelial cells with leukocytes and plays a fundamental role in the pathogenesis of coronary atherosclerosis. ICAM-1 single-base C/T polymorphism, which determines an amino acid substitution in the ICAM-1 protein in exon 6 codon 469, has been described. Our purpose was to determine whether this C/T polymorphism influences the risk of coronary heart disease (CHD) and myocardial infarction (MI) in humans.

Left ventricular diastolic function in physiologic and pathologic hypertrophy.

Background: Patients with hypertensive heart disease and left ventricular hypertrophy demonstrate an impaired left ventricular diastolic filling pattern. The aim of this study was to find out whether physiologic left ventricular hypertrophy induced by endurance training causes disturbances in left ventricular systolic and diastolic filling.

Methods: We examined 49 athletes with left ventricular (LV) hypertrophy due to endurance training, 49 patients with LV hypertrophy due to arterial hypertension, and 26 untrained healthy control subjects by conventional echocardiography.

Detection of microscopic cracks in dental ceramic materials by fluorescent penetrant method.

Ceramic materials are used as implants and prostheses because of their excellent biocompatibility and in the dental field beyond that, because of esthetic advantages and the little plaque accumulation. A disadvantage is their sensitivity to microscopic cracks because of their brittleness. Strength-deteriorating microscopic cracks can be introduced into the ceramic surface by the manufacturing process.

Quantitative analysis of experiments on bacterial chemotaxis to naphthalene.

A mathematical model was developed to quantify chemotaxis to naphthalene by Pseudomonas putida G7 (PpG7) and its influence on naphthalene degradation. The model was first used to estimate the three transport parameters (coefficients for naphthalene diffusion, random motility, and chemotactic sensitivity) by fitting it to experimental data on naphthalene removal from a discrete source in an aqueous system. The best-fit value of naphthalene diffusivity was close to the value estimated from molecular properties with the Wilke-Chang equation.

Left ventricular hypertrophy and diastolic dysfunction in healthy pregnant women.

Objective: The purpose of this study was to examine which hemodynamic parameters change under the natural volume overload of pregnancy.

Study Design: 46 healthy pregnant women were echocardiographically examined during the course of pregnancy. To evaluate left ventricular diastolic function, mitral inflow and pulmonary venous flow profiles were used.