Reversal mechanism of an individual Ni nanotube simultaneously studied by torque and SQUID magnetometry.

Using an optimally coupled nanometer-scale SQUID, we measure the magnetic flux originating from an individual ferromagnetic Ni nanotube attached to a Si cantilever. At the same time, we detect the nanotube's volume magnetization using torque magnetometry. We observe both the predicted reversible and irreversible reversal processes. A detailed comparison with micromagnetic simulations suggests that vortexlike states are formed in different segments of the individual nanotube. Such stray-field free states are interesting for memory applications and noninvasive sensing.

Cantilever magnetometry of individual Ni nanotubes.

Recent experimental and theoretical work has focused on ferromagnetic nanotubes due to their potential applications as magnetic sensors or as elements in high-density magnetic memory. The possible presence of magnetic vortex states-states which produce no stray fields-makes these structures particularly promising as storage devices. Here we investigate the behavior of the magnetization states in individual Ni nanotubes by sensitive cantilever magnetometry. Magnetometry measurements are carried out in the three major orientations, revealing the presence of different stable magnetic states. The observed behavior is well-described by a model based on the presence of uniform states at high applied magnetic fields and a circumferential onion state at low applied fields.

[Coincident manifestation of mesotheliomas of the tunica vaginalis and pleura. Case report and literature overview]. / Gleichzeitige Manifestation von Mesotheliomen der Tunica vaginalis und der Pleura. Kasuistik und Literaturübersicht.

Malignant mesotheliomas are rare entities (0.1-0.2% of all malignant tumors) possibly localized at the pleura, peritoneum, pericardium, and tunica vaginalis. Most malignant mesotheliomas are caused by asbestos inhalation. We report on a man who suffered from malignant mesotheliomas of the tunica vaginalis and of the pleura simultaneously. The development of these tumors was probably multicentric; the patient had been exposed to asbestos over a period of 22 years. We discuss the individual findings and the current literature.

[Induction of urothelial carcinoma due to chronic arsenic ingestion? A occupational medicine-toxicological excursion]. / Induktion von Urothelkarzinomen durch chronische Arseningestion? Ein arbeitsmedizinisch-toxikologischer Exkurs.

Whether chronic intoxication with arsenic can induce cancer of the urinary tract is an important question in urology and occupational medicine. Here, we consider potential exposure, and discuss the epidemiology and toxicology of arsenic. In addition, we conceptualize a possible strategy for clinical procedures.

Design and performance of a bioreactor system for mechanically promoted three-dimensional tissue engineering.

There is currently considerable interest in increasing the response of mesenchymal cells to physical forces, and numerous loading devices have been used to increase the formation of skeletal tissue in vivo and in vitro. We have developed a bioreactor system to apply cyclic strains on three-dimensional specimens over a range of 0-20,000 mustrain. The piezoelectric-driven mechanism allows the precise adjustment and control over load-related deformations of tissue, as shown by finite-element calculations of deformation of a collagen gel under load. We present the design of the bioreactor and its performance in specimens of tissue containing activated osteoblasts and chondrocytes. Biaxial tissue straining at 2,000 mustrain led to a substantial increase in the number of both types of cell compared with unstimulated controls. The synthesis of cell-specific extracellular matrix proteins increased when physiological loads (2,000 mustrain) were applied in the bioreactor, whereas higher deformations (20,000 mustrain) resulted in a reduction in proliferation and differentiation of cells. The mechanisms whereby mechanical stimulation leads to a defined cell reaction are not known, but the application of physiological micromovements in extracorporeal tissue chambers is a promising approach to the formation of hard tissue.

[Aggressive fibromatosis in the jaw and facial region with bone involvement. A review]. / Aggressive Fibromatose im Kiefer-Gesichts-Bereich mit ossärer Beteiligung. Eine Ubersicht.

BACKGROUND: Aggressive fibromatosis (AF) involving bones of the head is rare and surgery is often complicated by a high recurrence rate. Interdisciplinary treatment is of the utmost importance to avoid extensive, mutilating resection. Two cases emphasize the difficulties in the management. CASE REPORTS: A 67-year-old woman was referred to our unit with a blepharochalasis of the left upper palpebra and a palsy of the face on the left side. Her medical history included 12 operations over the previous 4 years for an extensive AF. MATERIAL AND METHODS: Our review includes all case reports of AF involving bones of the head published between 1960 and 2004. Additionally, our two cases are presented. Signs, symptoms and outcome were analyzed in relation to different treatment options. CONCLUSION: According to the literature, surgery is the most common treatment for AF in the head and neck region. Alternative modes of therapy must be considered because of the high recurrence rate and to avoid mutilating operations.

Basic reactions of osteoblasts on structured material surfaces.

In order to assess how bone substitute materials determine bone formation in vivo it is useful to understand the mechanisms of the material surface/tissue interaction on a cellular level. Artificial materials are used in two applications, as biomaterials alone or as a scaffold for osteoblasts in a tissue engineering approach. Recently, many efforts have been undertaken to improve bone regeneration by the use of structured material surfaces. In vitro studies of bone cell responses to artificial materials are the basic tool to determine these interactions. Surface properties of materials surfaces as well as biophysical constraints at the biomaterial surface are of major importance since these features will direct the cell responses. Studies on osteoblastlike cell reactivity towards materials will have to focus on the different steps of protein and cell reactions towards defined surface properties. The introduction of new techniques allows nowadays the fabrication of materials with ordered surface structures. This paper gives a review of present knowledge on the various stages of osteoblast reactions on material surfaces, focused on basic cell events under in vitro conditions. Special emphasis is given to cellular reactions towards ordered nano-sized topographies.

[Peri-implant bone formation around cylindrical and conical implant systems]. / Tierexperimentelle Evaluation des periimplantären Knochens bei zylindrischen gegenüber konischen Implantattypen.

BACKGROUND: The treatment of patients with early or immediately loaded dental implants has renewed interest in the behavior of osseointegration at the implant surface. Whereas it is generally accepted that peri-implant tissue formation and mineralization are dependent on the local mechanical environment in the interface zone, controversies exist concerning the impact of implant design on peri-implant bone formation. The aim of the present study was the in vivo evaluation of peri-implant bone formation by two different implant systems: cylindrical (ITI) versus conical (ILI). MATERIAL AND METHOD: A total of 60 implants (30 ITI and 30 ILI) were placed in the cranial and caudal part of the tibia of eight Göttinger minipigs. Half of the minipigs were sacrificed at 7 days and 28 days of osseointegration. Implant-containing bone specimens were prepared for histological and ultrastructural investigations. RESULTS: Histological and scanning electron-microscopic investigations showed a direct contact of bone-like minerals over the whole implant surface from day 7 of implant/bone interaction. Whereas the ILI implant showed direct contact up to the top of the crestal bone, ITI implants demonstrated a crestally located narrow gap without ossification over the whole experimental period. CONCLUSION: Our investigations support the hypothesis of an implant design-inherent emergence and maintenance of crestal bone.

[Odontogenic foci--possible etiology of urticaria?]. / Odontogene Foci-mögliche Ursache einer Urtikaria?

Recent studies have shown that chronic odontogenic infections could pose a risk for myocardial infarction, cerebral ischemia, and arteriosclerosis. However, the correlation between urticaria and dental infections has rarely been examined so far. Therefore, we performed a case-control study using a standardized questionnaire and examination. We investigated 66 patients suffering from an acute or chronic urticaria and 65 age- and sex-matched healthy patients as a control group. Dental status was determined by a so-called total dental index (TDI) which primarily reflects caries, periodontitis, periapical lesions, and nonvital and missing teeth. All 66 patients were referred from the department of dermatology. After their treatment in hospital, all patients received a questionnaire with questions on intensity and localization of the urticaria. The TDI of the urticaria patients was slightly better ( n=66; 2.6+/-1.98) than that of the control group ( n=65, TDI=3.3+/-1.86). Subsequently, it was determined if the urticaria had receded after dental treatment. In conclusion, chronic dental infections do not seem to correlate with an increased risk for urticaria.

[Primary implant stability with different bone surgery techniques. An in vitro study of the mandible of the minipig]. / Primäre Implantatstabilität bei unterschiedlichen Knochenaufbereitungstechniken. Eine In-vitro-Untersuchung am Unterkiefer des Minischweins.

The treatment concept of osseointegration is based on a stable embodiment of implants in bone and the maintenance of stability during functional load. A goal of the surgical preparation technique is therefore to obtain a stable and firm implant anchorage. The aim of this study was to evaluate implant stability after different surgical treatment of the bony implantation bed. Thirty cylindrical solid-screw-shaped implants with standard SLA ITI configuration were implanted into the explanted mandibles of five minipigs. The implant sites were prepared either by a conventional burr technique (group A), by burr technique with additional thread cutting (group B), or by the osteotome technique (group C). Primary implant stability was evaluated by resonance frequency analysis and removal torque test. The average value of the resonance frequency analysis (RFA) was 6000+/-469 cycles/s in group A, 5700+/-557 cycles/s in group B, and 5540+/-527 cycles/s in group C. Removal torque values of group A (507+/-57 Nmm) were significantly higher than those of group B (466+/-45 Nmm) and group C (240+/-31 Nmm) (between group A and C p<0.05, group A to B p=0.39, and B to C p<0.05). It can be concluded from this study that the conventional burr technique achieves a statistically significantly better primary bone anchorage than the osteotome technique.

The Paget-Schroetter syndrome: work accident and occupational disease.

INTRODUCTION: Primary thrombosis of the upper extremity (Paget-Schroetter syndrome, effort thrombosis) is usually not accepted either as a work-related accident or an occupational disease by the industrial injuries insurance authorities. This study aims to look at the circumstances under which this kind of thrombosis may be recognised as an occupational hazard. MATERIALS AND METHODS: After thoroughly studying the clinical records of 82 patients with thrombosis of the upper extremity in the outpatient department for angiology during a 10-year period, we found that in 51 cases the thrombosis was caused by secondary reasons (i.e., central venous catheterisation, malignoma, hypercoagulability, postoperative). In the remaining 31 patients, we painstakingly conducted a general and occupational history and further clinical, laboratory or technical investigations to differentiate the aetiology. RESULTS: Twenty-eight of 31 patients with suspected primary thrombosis of the axillary or subclavian vein (Paget-Schroetter syndrome) showed unusual private or occupational physical exercise as the underlying cause. Sixteen patients reported only short physical exercise up to several hours or acute trauma. Longer physical exercise periods (several days, months or even more) were found in 12 patients. Ten of the 28 patients who acquired the thrombosis doing occupational tasks covered by the industrial insurance, may be eligible for compensation. In 4 of these 10 insured cases, we found strong hints for work accidents, 6 patients of this group apparently revealed criteria of occupational diseases. Four of the 28 patients had a combination of physical effort and additional thrombogenic risk factors (cardiac pacemaker, hypercoagulability). CONCLUSION: Primary thrombosis of the upper extremity (Paget-Schroetter syndrome) should be announced to and compensated by the industrial injuries insurance either as work-related accident or occupational disease if the patient's occupational history shows close relationship between thrombosis manifestation and extraordinary physical efforts or exercises during occupational strains. For this reason, we recommend the recognition of the Paget-Schroetter syndrome in the national list of occupational diseases.

Paget-Schroetter syndrome in sports activities--case study and literature review.

The authors report 7 patients with thromboses in the upper extremity resembling Paget-Schroetter syndrome. According to their case histories, all patients had a temporal and causal relationship between partially unusual sports activities and the genesis of the thrombosis. The cause of this condition is a strain on the subclavian and axillary veins by retroversion or hyperabduction of the arm. This can entail microtraumatizations of the venous intima, consequently leading to a consecutive local activation of coagulation and to a possible thrombosis of the vessel. A mechanical compression of the vein by adjoining bone, ligament, and muscle structures can intensify the effects. Further primary diseases and risk factors as secondary causes for thromboses where taken into consideration when examining the patients. The Paget-Schroetter syndrome should be considered as a possible cause for unspecified trouble in the upper extremity reported by athletes. If such prolapses occur, they can be categorized as accidents by private and statutory insurance companies that cover accidents.

[Nitrate headache in blasting work]. / Nitratkopfschmerz bei Sprengarbeiten.

CASE REPORT: A 34-year-old white male was executing blasting works in an operation of a quarry several times a month during a period of 1 year. Each time he worked with explosives, he complained of headache, vertigo and concentration failure which started shortly after beginning and continued several hours after. The results of the physical examination on a day without blasting works were normal. Because of the exact working parallel appearance of the symptoms we did further explorations at the workplace which showed the usage of nitroglycerin blasting agents without observance of the safety regulations. The symptoms only at blasting workdays with normal clinical findings at break led considering the relation with the occupational conditions to the diagnosis "headache due to exposure to nitroglycerin explosives". It was reported to the employer's liability insurance association as an occupational disease with the aim of improving occupational conditions. CONCLUSION: Occupational toxic agents as a potential trigger of unclear headache support the requirement of an exact anamnesis of working conditions and environment.

[Paget-von Schroetter syndrome as an occupational accident]. / Paget-von Schroetter-Syndrom als Arbeitsunfall.

HISTORY AND CLINICAL FINDINGS: Two men and one woman developed typical symptoms of a thrombosis in the arms after unusual physical effort at their work place (a coal miner after a bad fall, a radiographer after having to catch a patient, a painter after jerkily moving a heavy piece of furniture). INVESTIGATIONS AND DIAGNOSIS: In all three patients a thrombosis of the subclavian vein was demonstrated by duplex scans or phlebography. In two patients tests for hypercoagulability were unremarkable. None of the patients had a thoracic outlet syndrome. TREATMENT AND COURSE: After initial local thrombolytic or heparin therapy alone, phenprocoumon treatment over several months was given in two cases, and in one case low-molecular-weight heparin was administered over several months. All three patients complained of strain-related residual symptoms in the affected arm (pain, swelling, easy fatigability). In all three cases, the accident insurer recognized the incident to be a work-related accident. CONCLUSION: Patients with a Paget-Schroetter syndrome resulting from a sudden and unusual physical effort at work, which is covered by statutory accident insurance, must be reported to the accident insurer as a work-related accident in order to safeguard individual medical claims of the patient and for general medical and epidemiological reasons.

[Paget-Schroetter syndrome caused by wrestling]. / Paget-von Schroetter-Syndrom durch Ringsport.

Upper extremity thrombosis (Paget-Schroetter syndrome) hints already at physical strains with regard to the synonymous term "effort thrombosis". We report two cases of upper extremity thrombosis caused by wrestling. Wrestling as an example of martial arts activity leads to traumatic venous intima lesions with resulting local activation of coagulation as a main reason in pathogenesis of these thromboses. The possibility of a Paget-Schroetter syndrome should be considered in differential diagnosis if upper extremity complaints of unknown origin occur after wrestling matches. This kind of subclavian vein thrombosis should be reported to the accident insurance.

[Abscessed pneumonia caused by Pseudomonas aeruginosa as an occupational disease in a metal driller]. / Abszedierende Pneumonie durch Pseudomonas aeruginosa als Berufskrankheit bei einem Bohrwerksdreher.

We report the case of a 29-year-old man without immunodeficiency who acquired Pseudomonas aeruginosa pneumonia complicated by pulmonary abscess. The source of infection could be identified as aerosolized metalworking fluid at his workplace contaminated with Pseudomonas aeruginosa. A high titer of specific IgG antibodies (type-III-sensitization, Gell & Coombs) against Pseudomonas aeruginosa has been identified in the patients serum as an indicator for longstanding occupational airborne exposure to contaminated metalworking fluid. This community-acquired pneumonia has been reported to the industrial injuries insurance as an occupational disease for discussion of legal consequences and development of effective measures of prevention.