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Scientific Aspects (scientific + aspect)
Selected AbstractsClinical pharmacology and therapeutic use of antioxidant vitaminsFUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 2 2007Ramón Rodrigo Abstract The clinical use of antioxidants has gained considerable interest during the last decade. It was suggested from epidemiological studies that diets high in fruits and vegetables might help decrease the risk of cardiovascular disease. Therefore, supplements of vitamins C and E were applied through protocols aimed to prevent diseases such as atherosclerosis, preeclampsia or hypertension, thought to be mediated by oxidative stress. Despite the biological properties of these vitamins could account for an effective protection, as shown by several clinical and experimental studies, their efficacy remains controversial in the light of some recent clinical trials and meta-analyses. However, the methodology of these studies, criteria for selection of patients, the uncertain extent of progression of the disease when initiating supplementation, the lack of mechanistic studies containing basic scientific aspects, such as the bioavailability, pharmacokinetic properties, and the nature of the antioxidant sources of vitamins, could account for the inconsistency of the various clinical trials and meta-analyses assessing the efficacy of these vitamins to prevent human diseases. This review presents a survey of the clinical use of antioxidant vitamins E and C, proposing study models based on the biological effects of these compounds likely to counteract the pathophysiological mechanisms able to explain the structural and functional organ damage. [source] Bodensystematik und Bodenklassifikation Teil I: GrundbegriffeJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 1 2005Christoph Albrecht Abstract Bodenordnungssysteme lassen sich meist nach zwei Prinzipien entwickeln: Entweder werden nur rein bodenkundliche Informationen als kategorisierendes Merkmal verwendet (pedogenetische Faktoren/Prozesse), oder die Kategorienbildung erfolgt problemorientiert anhand ausgewählter Parameter. Die meisten der weltweit verwendeten Bodenordnungssysteme lassen sich nach ihrer Grundausrichtung einem der beiden Typen zuordnen. Diese Betrachtungsweise ist nicht neu und wird in der Literatur mit unterschiedlichen Begriffen und Begriffsinhalten dargestellt. In der vorliegenden Arbeit werden die verschiedenen Definitionen von Systematik, Klassifikation, Taxonomie und Identifizierung zusammengefasst und geordnet. Dabei fällt auf, dass Begriffe mit sehr unterschiedlichen Inhalten oft synonym verwendet werden. Grundgedanke unserer Überlegungen ist die Trennung von Systematik, Klassifikation und Identifizierung. Systematik ist die grundsätzliche wissenschaftlich-deduktive Gliederung von Objekten in systematische Einheiten. Dabei soll das gesamte Wissen eines Fachgebietes in eine überschaubare Form gebracht werden, im Mittelpunkt stehen sowohl die umfassende Beschreibung einzelner Objekte als auch die Beziehungen zwischen den Objekten. Im Gegensatz dazu ist eine Klassifikation die zielorientiert-induktive Gliederung von Objekten. Die entstehenden Klassen werden nur anhand ausgewählter Parameter abgegrenzt, womit ein schneller Überblick bei speziellen Fragestellungen ermöglicht wird. Die Identifizierung ist die Einordnung von neuen Objekten in eine bestehende Systematik oder Klassifikation. Eine zweifelsfreie Identifizierung erfordert die Messbarkeit der kategorisierenden Merkmale. Bei einer genetisch angelegten Bodensystematik sind die Merkmale die Boden bildenden Prozesse und Faktoren. Da sie beim gegenwärtigen Kenntnisstand oft nicht messbar sind, bleiben Versuche, einen Boden in eine Systematik einzuordnen, häufig hypothetisch und dadurch subjektiv. Die Ergebnisse einer Bodensystematisierung sind daher oft anfechtbar, weil sie nicht durch Messwerte verifiziert werden können. Im Gegensatz dazu erlauben Bodenklassifikationen objektive Profilansprachen. Da jedoch die Festlegung der Grenzwerte eher pragmatisch nach Zweckmäßigkeit geschieht und nicht wissenschaftlich anhand von Prozessintensitäten, ist die Verwendung als grundlegendes Ordnungssystem eines Wissenschaftsgebietes nicht möglich. Die Bodenkunde benötigt beide Arten von Ordnungssystemen, um wissenschaftliche und praktische Ansprüche gleichermaßen erfüllen zu können, jedoch erfordern die Vollendung und Verifizierung der Systematik umfangreiche Forschungsarbeiten. Kurzfristig ist dieses Problem nur durch die Entwicklung einer kennwertbasierten Klassifikation lösbar, mit der die Kategorien der bestehenden Systematik so gut wie möglich nachgebildet werden. Langfristig ist die exakte Erforschung und Modellierung der Boden bildenden Prozesse aber unumgänglich. Soil systematics and classification systems Part I: Fundamentals Soil-ordering systems are primarily based and developed on one of two underlying principles: They are either categorized according to soil-forming processes, or the formation of categories develops by chosen parameters. This perspective has already been established in the literature, though it is often confusing as many terms are defined and applied differently. In this contribution, the various definitions of systematics, classification, taxonomy, and identification will be clearly differentiated and summarized. The core of our work is to clearly define and contrast three terms: systematics, classification, and identification. Systematics is the fundamental scientific and deductive ordering of objects into systematic units. The purpose of this approach is to organize the entire spectrum of knowledge within a discipline into a transparent and manageable form. Classification, in direct contrast to systematics, is goal-oriented and an inductive ordering of objects. Thus, the ordering scheme consists of classes which are clearly parameterized. Identification is the ordering of new objects into an already existing systematics or classification system. Close attention is paid to both the differences and the similarities between a systematics and a classification system, especially pertaining to their practical applications. The identification requires that the category-forming characteristics can be measured (e.g., for soil systematics, these are the soil-forming processes and factors). Currently, it is unfortunately not feasible to objectively quantify most soil-forming processes. Thus, most attempts at categorizing soils by systematics are hypothetical and highly subjective in nature. The resulting identification derived from the soil systematics approach is open to questions and contestable, since a graded measuring system does not yet exist to verify these determinations. In contrast, a soil-classification system does allow an objective soil-profile identification, although such systems are conceived pragmatically and designed for a practical purpose (e.g., not scientifically based on process intensities). Unfortunately, such a classification system cannot be applied as a universal scientific categorization system due to this method of conception. Both categorization approaches are required in soil science in order to satisfy both the practical and the scientific aspects of the field. However, substantial research must be done to complete and verify systematics. The only viable short-term solution is through the development of a graded classification system where the categories of the system are directly derived from the current systematics approach. In the long run both the exact investigation and the detailed modeling of the soil-forming processes are inevitable. [source] Gene therapy legislation in The NetherlandsTHE JOURNAL OF GENE MEDICINE, Issue 10 2007D. A. Bleijs Abstract Several regulatory organisations are involved in the assessment of clinical gene therapy trials involving genetically modified organisms (GMOs) in The Netherlands. Medical, ethical and scientific aspects are, for instance, evaluated by the Central Committee on Research Involving Human Subjects (CCMO). The Ministry of Housing, Spatial Planning and the Environment (VROM) is the competent authority for the environmental risk assessment according to the deliberate release Directive 2001/18/EC. A Gene Therapy Office has been established in order to streamline the different national review processes and to enable the official procedures to be completed as quickly as possible. Although the Gene Therapy Office improved the application process at the national level, there is a difference of opinion between the EU member states with respect to the EU Directive according to which gene therapy trials are assessed, that urges for harmonisation. This review summarises the gene therapy legislation in The Netherlands and in particular The Netherlands rationale to follow Directive 2001/18/EC for the environmental risk assessment. Copyright © 2007 John Wiley & Sons, Ltd. [source] Gene therapy for cartilage defectsTHE JOURNAL OF GENE MEDICINE, Issue 12 2005Magali Cucchiarini Abstract Focal defects of articular cartilage are an unsolved problem in clinical orthopaedics. These lesions do not heal spontaneously and no treatment leads to complete and durable cartilage regeneration. Although the concept of gene therapy for cartilage damage appears elegant and straightforward, current research indicates that an adaptation of gene transfer techniques to the problem of a circumscribed cartilage defect is required in order to successfully implement this approach. In particular, the localised delivery into the defect of therapeutic gene constructs is desirable. Current strategies aim at inducing chondrogenic pathways in the repair tissue that fills such defects. These include the stimulation of chondrocyte proliferation, maturation, and matrix synthesis via direct or cell transplantation-mediated approaches. Among the most studied candidates, polypeptide growth factors have shown promise to enhance the structural quality of the repair tissue. A better understanding of the basic scientific aspects of cartilage defect repair, together with the identification of additional molecular targets and the development of improved gene-delivery techniques, may allow a clinical translation of gene therapy for cartilage defects. The first experimental steps provide reason for cautious optimism. Copyright © 2005 John Wiley & Sons, Ltd. [source] A review of littoral tourism, sport and leisure activities: consequences on marine flora and faunaAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 4 2001Gerard L. Bellan Abstract 1.,A report on the scientific aspects of the consequences of tourism and other leisure activities on the marine flora and fauna has been prepared on behalf of the French Ministry of the Environment. This involved an exhaustive bibliographical review resulting in a series of proposals to address some of the issues highlighted. 2.,Our knowledge is too often based on observations of the deeds and misdeeds of tourism along with only a small amount of experimental study. 3.,The main proposals are that there should be: (1) a compilation of all studies ordered by and for the State and its decentralized services, local communities and private companies; (2) definition of priority species and ecosystems; (3) observations on the direct and indirect impacts by tourists and sportsmen on the natural environment for each one of the large biotopes; (4) quantification of the impact of recreational fishing; (5) an integration of biological, sociological, economic and judicial disciplines in the management of the marine environment. Copyright © 2001 John Wiley & Sons, Ltd. [source] | ||||||||||