An XPS and SEM evaluation of six chemical and physical techniques for cleaning of contaminated titanium implants

The purpose of the present study was to analyse clinically failed and retrieved implants prior to and after cleaning by means of scanning electron microscopy (SEM) and X-ray induced photoelectron spectroscopy (XPS) as compared to unused controls. Six different chemical and physical techniques for cleaning of contaminated titanium implants were evaluated: 1) rinsing in absolute ethanol for 10 min, 2) cleaning in ultrasonic baths containing trichloroethylene (TRI) and absolute ethanol, 10 min in each solution, 3) abrasive cleaning for 30 s, 4) cleaning in supersaturated citric acid for 30 s, 5) cleaning with continuous CO2-laser in dry conditions at 5 W for 10 s, 6) cleaning with continuous CO2-laser in wet conditions (saline) at 5 W for 10 s. SEM of failed implants showed the presence of contaminants of varying sizes and XPS showed almost no titanium but high carbon signals. XPS of unused titanium implants showed lower levels of titanium as previously reported, probably due to contamination of carbon which increased with time in room air. Cleaning of used implants in citric acid followed by rinsing with deionized water for 5 min followed by cleaning in ultrasonic baths with TRI and absolute ethanol gave the best results with regard to macroscopical appearance and surface composition. However, as compared to the unused implants the results from an element composition point of view were still unsatisfactory. It is concluded that further development and testing of techniques for cleaning of organically contaminated titanium is needed.     

Systemic and peritoneal host defense in peritonitis

Most of the work of host defense has been carried out in mixed patient populations. It is now clear that elective preoperative surgical patients have totally different host defense capabilities as compared to posttrauma patients or those suffering from peritonitis. Specific cell-mediated immune studies need to be repeated in these 2 patient groups as well. What will contribute clinical relevance to these studies will be the means to correct the defects. If these defects or—more correctly termed—abnormalities of host defense are, indeed, important and contribute to an increased sepsis rate and mortality from sepsis in affected patients, then correcting them should reduce these complications. This hypothesis can only be tested when such means become available. The issues of most interest in the next few years will be the significance of serum albumin in host outcome, the role of immunomodulators, the involvement of cytokines in the overall process of host defense, and the use of specific nutritional support regimens targeted to the immune system.

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Resumen La mayor parte del trabajo sobre los mecanismos de defensa del huésped ha sido realizada en poblaciones mixtas de pacientes. Actualmente aparece claro que los pacientes preoperatorios electivos poseen una capacidad de defensa de huésped totalmente diferente que la de los pacientes en estado posttrauma o de aquellos con peritonitis. Aparece necesario realizar estudios específicos de inmunidad celular en estos 2 grupos de pacientes; aquello que aporte pertinencia clínica en tales estudios habrá de representar medios para corregir estos defectos. Si tales defectos, mejor denominados anormalidades en las defensas del huésped, son de verdad importantes y contribuyen a mayores tasas de infección y de mortalidad por sepsis en los pacientes afectados, su corrección debe resultar en reducción de estas complicaciones. Esta hipótesis sólo puede ser puesta a prueba cuando tales medios se hallen disponibles. Los aspectos de mayor interés en los próximos años serán el significado de la albúmina sérica en la evolución final del huésped, el papel de los inmunomoduladores, la participación de las citocinas en el proceso general de defensa del huésped, y el uso de regimenes especificos de soporte nutricional dirigidos hacia el sistema inmune.

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Résumé La plupart des travaux sur les mécanismes de défense ont été faits sur les populations mixtes. Il est à présent certain que les patients opérés électivement ont des mécanismes de défense préopératoire totalement différents de ceux des traumatisés ou des patients ayant une infection péritonéale. Les études immunologiques sur la médiation cellulaire spécifique méritent d'être refaites chez ces deux populations. Ce qui ressortira de ces études donnera les moyens de corriger les défauts ou plutôt les anomalies des mécanismes de défense qui contribuent à augmenter septicité et mortalité en rapport avec l'état septique. Cette hypothèse ne peut être vérifiée qu'avec ces moyens. Les questions les plus intéressantes dans les années à venir sera peut-être de connaître l'influence de l'albumine sérique sur l'évolution, le rôle des immunomodulaterus, celui des cytokinines dans le procédé global des mécanismes de défense, et celui de l'utilisation de l'alimentation spécifique pour améliorer le système immune.

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Supported in part by grants from the Medical Research Council of Canada and the Fonds de recherche de Santé.     

Carbon blacks as EPR sensors for localized measurements of tissue oxygenation.

New electron paramagnetic resonance (EPR) oximetry probes were identified in the class of carbon black materials. These compounds exhibit very high oxygen sensitivity and favorable EPR characteristics for biological applications. At low pO(2), the linewidth is particularly sensitive to changes in oxygen tension (sensitivity of 750 mG/mmHg). The application of the probes for oximetry was demonstrated in vivo: the pO(2) was measured in muscle in which the blood flow was temporarily restricted as well as in tumor-bearing mice during a carbogen breathing challenge. The responsiveness to pO(2) was stable in muscle for at least 3 months. No toxicity was observed using these materials in cellular experiments and in histological studies performed 2, 7, and 28 days after implantation. In view of their EPR characteristics (high sensitivity) as well as the well-characterized production procedure that make them available on a large scale, these probes can be considered as very promising tools for future developments in EPR oximetry.     

Physical training and multiple sclerosis.

For many years, patients with multiple sclerosis (MS) were advised to avoid exercise because of the risk of increased neurological impairment. This article reviews the literature related to MS and physical exercise. Physical exercise depends on patients' physiological tolerance and response to exercise. MS patients can exhibit dysfunction of cardiovascular adjustment accompanied by respiratory involvement, which can alter aerobic capacity. These abnormalities tend to increase with the neurological impairment. Muscle weakness is the consequence of not only altered central motor drive but also disuse. Several studies have shown the benefits of physical training, with improvements in aerobic capacity, gait parameters and fatigue, and an influence on quality of life. Regular aerobic physical activity is necessary to maintain the benefit of physical training.     

Gabapentin-induced coma: A MR-spectrometry analysis

As for the majority of antiepileptic drugs, encephalopathy, manifested by transient somnolence, mood and motor disorders, is a possible side-effect. To our knowledge, there is little information about gabapentin-induced coma. We report a third case of gabapentin-induced coma where magnetic resonance-spectrometry was performed in diagnosis assessment.     

Das Jo-1-Syndrom und seine klinischen Manifestationen

Namensgebend für das Jo-1-Syndrom sind Autoantikörper gegen das Jo-1-Antigen, die bei diesem Krankheitsbild im Serum der betroffenen Patienten nachgewiesen werden. Der Name Jo-1 leitet sich von dem ersten Patienten (John P.) ab, bei dem diese Antikörper gefunden wurden. Dieser Patient litt an einer Polymyositis und fibrosierenden Alveolitis. Das Jo-1-Antigen ist identisch mit der Histidyl-Transfer-RNA-Synthetase im Zytosol. Das Jo-1-Syndrom gehört zu einer Familie von Autoimmunerkrankungen, die als Anti-Synthetase- Syndrome bezeichnet werden. Diese Syndrome haben gemeinsam, dass jeweils Autoantikörper gegen unterschiedliche Aminosäure-Transfer-RNASynthetasen nachweisbar sind. Klinisch handelt es sich beim Jo-1-Syndrom um eine Sonderform der Poly- bzw. Dermatomyositis von bisher ungeklärter Ätiologie. Neben einer Muskelbeteiligung kommt es charakteristischerweise zu einer interstitiellen Lungenbeteiligung, die auch prognostisch das Krankheitsbild bestimmt. Zusätzlich können klinisch eine Polyarthritis und weitere Symptome bestehen, die dem klinischen Bild anderer Kollagenosen ähneln. Ebenso wie die Polymyositis und Dermatomyositis kann sich das Jo-1-Syndrom in sog. Myositis-Overlap-Syndromen präsentieren. Zu dieser Diagnose führt ein Symptomenkomplex, der die klare Zuordnung zu einer einzelnen Erkrankung nicht möglich macht. Häufig werden in solchen Fällen U1-RNP-Antikörper nachgewiesen. Therapeutisch spricht das Jo-1-Syndrom auf die Gabe von Kortikosteroiden und—falls notwendig—Azathioprin, Methotrexat und Cyclophosphamid an. Eine Kurzbeschreibung von zwei klinischen Fällen stellt das Krankheitsbild anschaulich dar.     

Aortic prosthetic ring annuloplasty: a useful adjunct to a standardized aortic valve-sparing procedure?

OBJECTIVE: Dilation of aortic annulus, sinuses of Valsalva, and sinotubular junction (STJ) diameters are the characteristic lesions of aortic root aneurysm. The remodeling technique reduces STJ diameter and creates three neosinuses of Valsalva. Alternatively, the reimplantation technique reduces both annulus and STJ diameters to the detriment of aortic root dynamics. Although the remodeling technique is recognized as the most physiological valve-sparing procedure, aortic annulus dilation may jeopardize its results. A standardized approach that combines an external subvalvular aortic prosthetic ring annuloplasty with the remodeling technique is suggested. METHODS: Eighty-three patients underwent an elective aortic root remodeling procedure, either isolated (group 1, n=34) or combined with an external subvalvular aortic prosthetic ring annuloplasty (group 2, n=49). Preoperative aortic regurgitation was 1.59+/-1.1 (group 1) and 1.97+/-1.3 (group 2) (NS). The aortic annulus was more dilated in group 2 than in group 1 (27+/-2.77 mm vs 26.4+/-2.3 mm, p<0.01). Residual aortic regurgitation > or =grade II was the conversion criteria for aortic valve replacement. RESULTS: Operative mortality was 3.6% (n=3). Intraoperative conversion for valve replacement was 32.7% in group 1 (n=11) versus 4.2% in group 2 (n=2) (p<0.001). In group 1, preoperative annulus diameter was larger for converted than for valve-spared patients (27.6+/-1.7 mm vs 25.2+/-1.5 mm, p<0.02). In group 2, implanted aortic ring significantly reduced annulus diameter (20.6+/-1.8 mm) without significant aortic valve gradient (8.3+/-3 mmHg). Follow-up was 17.2+/-13.4 months (group 1) and 10.41+/-7.95 months (group 2). Reoperation for recurrent aortic regurgitation was 13% in group 1 (n=3) versus 4.2% in group 2 (n=2). Echocardiographic follow-up found residual aortic regurgitation < or =grade I in 17 patients in group 1 (90%) versus 43 patients in group 2 (95.5%) and of grade II in two patients in group 1 (10%) and two patients in group 2 (4.5%). CONCLUSION: The addition of external aortic prosthetic ring annuloplasty improves the remodeling technique's operative reproducibility and short-term results. Therefore, its use as a systematical adjunct to the remodeling procedure is suggested. However, further long-term evaluation comparing this valve-sparing procedure to composite graft replacement should define the best surgical strategy for aortic root aneurysm.