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Biomedical subjects

P Reuter

Publications and source records attributed to P Reuter.

At least 19 recordsLinked to original sources
PubMed2003

Surface composition analysis of failed cementless CoCr- and Ti-base-alloy total hip implants.

The surfaces of retrieved failed cementless total hip implants made of cobalt-chromium-molybdenum casting alloy and of wrought titanium 6-aluminum 4-vanadium alloy were studied with the use of scanning-electron microscopy (SEM), energy-dispersive X-ray analysis (EDX) and X-ray photoelectron spectroscopy (XPS). New implants of the same make served as controls. The XPS scans revealed a dense carbon layer on the entire analyzed specimen. The relative composition of the titanium alloy implants showed an overall agreement with the international standards for implants for surgery, and the overall surface composition did not change over the period of the implantation. However, an inhomogeneous distribution of the constituents could be demonstrated in the retrieved as well as in the new MEC-screw rings made of TiAl6V4 alloy, an implant that has been linked to a high early failure rate. In the CoCr-alloy components (Lord-screw rings) a high percentage of aluminum, mainly organized in aluminum inclusions, was found in the retrieved as well as in the new implants.

Adult↗
PubMed2001

Evaluating alternative cannabis regimes.

BACKGROUND: Cannabis policy continues to be controversial in North America, Europe and Australia. AIMS: To inform this debate, we examine alternative legal regimes for controlling cannabis availability and use. METHOD: We review evidence on the effects of cannabis depenalisation in the USA, Australia and The Netherlands. We update and extend our previous (MacCoun & Reuter, 1997) empirical comparison of cannabis prevalence statistics in the USA, The Netherlands and other European nations. RESULTS: The available evidence indicates that depenalisation of the possession of small quantities of cannabis does not increase cannabis prevalence. The Dutch experience suggests that commercial promotion and sales may significantly increase cannabis prevalence. CONCLUSIONS: Alternatives to an aggressively enforced cannabis prohibition are feasible and merit serious consideration. A model of depenalised possession and personal cultivation has many of the advantages of outright legalisation with few of its risks.

Adolescent↗
PubMed2001

Light and scanning-electron microscopic examination of coronary stents in a perfusion-model. Effects of an NO-donor/quantitative analysis.

Does a NO-donor (Corvaton, Aventis, France) attenuate the adherence and the aggregation of platelets in a closed-loop perfusion modell with or without the implantation of coronary stents? SIN-1, the active metabolite of molsidomine, exerted a strong influence on the interaction of platelets with the surfaces of stents. When SIN-1 was added the adherence of platelets to the surfaces of stents was markedly reduced. The sites were most of the platelets adhered to, also changed. More platelets adhered to the stent backbone and less to the free modular stent parts. The localisation of adherent platelets could easily be shown by light microscopy. The aggregation of platelets, accompanied by a spheroidic shape change, could be demonstrated by scanning electron microscopy on the addition of an NO-donor, not only a reduction of platelet adherence was realised but also the reduction of platelet aggregation.

Blood Platelets↗
PubMed1998

Drug policies and harms: a conceptual framework.

Existing indicators of drug-related policies and harms - official statistics, treatment data, and so on - are difficult to interpret and to compare across jurisdictions. We propose a conceptual framework including key dimensions of policy and harm. The framework is designed to guide creation of a new dataset in which existing empirical data can be used to assign city-specific scores on policy and harm dimensions. By an interpretive process involving local experts and a coordinating body, we believe that existing data can be evaluated and synthesized to derive these scores. We also propose a cumulative case-study method of querying the dataset to test hypotheses regarding relationships between policies and harms.

Crime↗
PubMed1998

[3-phase spiral CT of the liver, Value of non-contrast arterial and portal venous studies in the diagnosis of focal liver lesions].

PURPOSE: To assess the value of noncontrast, arterial and portal venous phase of triphasic helical CT in detecting and characterising focal liver lesions. MATERIAL AND METHODS: 120 patients with focal liver disease underwent triphasic helical CT examinations with a collimation of 6.5 mm at a table feed of 6.5 mm/s. The liver scans were obtained before the administration of 120 ml of non-ionic contrast material (flow 2 or 3 ml/s), at the arterial phase, and at the portal venous phase (20 s, respectively 60 s after injection). Patients were divided into four groups according to the underlying disease and enhancement pattern. The studies were evaluated retrospectively. RESULTS: A total of 269 lesions was seen. The noncontrast phase (NCP) revealed 86% of lesions, the arterial phase (AP) 95% and the portal venous phase (PVP) 91%. In the first group of hypovascular lesions (colorectal carcinoma) all lesions (73/73) were detected in the PVP. In the second group of hypervascular lesions (breast cancer, melanoma) the combination of AP and PVP revealed 73 of 74 lesions. In the third group of patients with unknown primary and detected lesions by sonography all 89 lesions were detected with the combination of AP and PVP. In the fourth group of patients with cirrhosis 3 of 33 lesions were detected exclusively during the AP and 3 other lesions exclusively during the NCP. To make a definitive diagnosis of focal liver lesions the value of the three phases was as follows: to characterise lesions the PVP was sufficient in 62%, the combination of PVP and AP in 27%, and the combination of all three phases in 11%. CONCLUSIONS: If hypovascular lesions are suspected examination during PVP is sufficient. In cases of hypervascular lesions and lesions of unknown primary AP and PVP should be combined. Unenhanced scans are of additional diagnostic value only in patients with liver cirrhosis.

Angiography↗
PubMed1997

Interpreting Dutch cannabis policy: reasoning by analogy in the legalization debate.

The Dutch depenalization and subsequent de facto legalization of cannabis since 1976 is used here to highlight the strengths and limitations of reasoning by analogy as a guide for projecting the effects of relaxing drug prohibitions. While the Dutch case and other analogies have flaws, they appear to converge in suggesting that reductions in criminal penalties have limited effects on drug use-at least for marijuana-but that commercial access is associated with growth in the drug-using population.

Adolescent↗
PubMed1997

[CT angiography of cerebral venous circulation: anatomical visualization and diagnostic pitfalls in interpretation].

PURPOSE: To show the frequency of visualisation of the dural sinuses and cerebral veins with CT-angiography (CTA) with special reference to anatomical variants. METHODS: 34 CTA (1 mm slice thickness, 120 ml nonionic KM, 2 ml/s flow, 40 s prescanning delay) were performed in 30 patients to examine the cerebral venous system. In an anatomic study of cadavers (n = 10) without known disease of the cerebral veins the great sinuses were opened and examined. RESULTS: The superior sagittal, the transverse, the sigmoid and the straight sinus could be evaluated in all cases (100%). The cortical and deep cerebral veins as well as the small sinuses were visualised in 12-97% of the examinations. A sinovenous thrombosis was diagnosed in 4 of the 30 patients. Asymmetric superior sagittal sinus bifurcation (12/30), a hypoplastic sinus transversus (2/30) and a persistent sinus occipitalis (4/30) were found as anatomical variants. In 10 of the 30 patients we discovered 17 dural sinus filling defects produced by large arachnoid granulations. Similar findings could be demonstrated in the pathologico-anatomic examination series. CONCLUSION: CT angiography is suitable for detailed evaluation of the cerebral veins. Anatomic variants, arachnoid granulations, as well as fibrous bands and septa, which may lead to misinterpretation in conventional CT, can be clearly demonstrated. The sensitivity and specificity of CT in diagnosis of sinovenous thrombosis were increased thereby.

Adolescent↗