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Biomedical subjects

W Raab

Publications and source records attributed to W Raab.

At least 19 recordsLinked to original sources
PubMed2004

Clinical field testing of trans-femoral prosthetic technologies: resin-wood and ICRC-polypropylene.

The aim of this study was to evaluate the use of 2 different trans-femoral prosthetic systems, a conventional wood-resin design and an ICRC polypropylene design, in a developing country when implemented by teachers and their associates at an ISPO Caegory II recognised training establishment. The study was conducted at the Tanzanian Training Centre for Orthopaedic Technologists (TATCOT). Amputees were selected from a cohort of younger amputees, mostly with traumatic amputations, 27 were provided with the conventional design of prosthesis and 35 with the ICRC design. The outcome was evaluated clinically and technically after a median of 20 months (conventional) and 15 months (ICRC) respectively. For all prostheses provided the craftsmanship was considered acceptable in 71%, and patient satisfaction was assessed as 92%, patient compliance as 98%. Failures requiring a major intervention represented 32%. Both systems provided in this controlled environment were considered to give an acceptable clinical and technical result.

Adolescent↗
PubMed2003

[Further development of the International Pneumoconiosis Classification--from ILO 1980 to ILO 2000 and to ILO 2000/German Federal Republic version].

The ILO (1980) Classification has been revised during recent years. The new version is now available as the International Classification of Radiographs of Pneumoconioses (Revised edition 2000). The Guidelines booklet is currently available only in English. Those involved felt it was important to maintain continuity with the ILO (1980) edition, in particular to retain the standard radiographs, despite their restricted quality, so as to ensure comparability with earlier national and international data sets. The standard films illustrating pleural abnormalities, and 'u'-shadows, have been modified and reconstituted. The most important changes relate to assessment of film quality, pleural abnormalities, and additional symbols. In Germany, film quality is characterised as "+", "+-", "+--" and "u" according to whether the ability to assess pneumoconiosis is judged to be unimpeachable ("+") to unusable ("u"). If a film is not classified as "+", then written comments regarding defects are required. For "diffuse" pleural thickening, the ILO (2000) edition now requires the presence also of obliteration of the costophrenic angle. This was not required in the earlier (1980) edition and, as previously, is also not stipulated in the German version. A minimum width of 3 mm (previously 0-5 mm), coded "a", is required both for plaques as well as for the margin to the lateral chest wall. Congruence is thus achieved for criteria, which, in German practice, lead to an indication of suspect occupational disease. Plaques on the diaphragm are not considered for measurement of extent; they are only coded as present or absent. If calcification is identified, then this must also be classified and measured as a localised plaque. Extent of calcification on its own, previously coded "0" to "3", is no longer specified. The following new symbols, illustrated by new diagrams, have been introduced: aa = atherosclerotic aorta; at = apical thickening; cg = calcified granuloma (or other non-pneumocononiotic nodules); me = mesothelioma (already previously differentiated from "ca" on the German record sheet); pa = plate atelectasis; pb= parenchymal bands; ra = rounded atelectasis; od = other disease. (Examples of the latter are illustrated diagrammatically by lobar pneumonia, aspergilloma, goiter and hiatal hernia.) Earlier national differences (ILO 1980/German Federal Republic) on particular issues have also been agreed among German "double-readers" ["Zweitbeurteiler"]. However, conformity between the original (ILO 2000) text and the national (German) modified text has been retained in large measure. The detailed descriptions of the standard films differ in certain respects from the German (1980) definitions. Some revision of individual descriptions of the films are proposed. Except for a few differences, agreement was reached here too. The definitive date for the change in Germany is expected to be in early 2004. The standard films are already available now through ILO offices in Geneva or Bonn (addresses in appendix.)

Germany↗
PubMed2003

Hohenheimer Consensus Talk. Oxidative and premature skin ageing.

To elucidate the scientific state of the art with respect to the role of nutrition in skin ageing, nine experts from different disciplines discussed the role of micronutrients on 'oxidative and premature skin ageing'. In this 25th Hohenheim Consensus Meeting, 13 questions were discussed and, based on published valid data, answered by mutual agreement. The consensus answers achieved during the meeting are justified by a scientific background text. The importance of in vitro and in vivo models regarding oxidative and premature skin ageing was critically evaluated. There was a special focus on prevention and intervention of skin ageing with nutrition. Finally, the paper summarizes the scientific background from different areas related to oxidative and premature skin ageing.

Animals↗
PubMed2003

Clinical field-testing of ATLAS prosthetic system for trans-femoral amputees.

The ATLAS prosthetic system was tested on 47 trans-femoral amputees in two tropical areas. Although the craftsmanship was not acceptable, 46% (16/35) were malaligned many with the foot dorsiflexed, the user compliance was good (91%, 32/35), and the satisfaction rate high (71%, 25/35). However, after 7-10 months failures occurred in 83% (29/35) mostly because of problems with the ATLAS knee mechanism. A modification was tested and 80% (12/15) had again failed at the knee after 6 (2-12) months. The ATLAS system in its current design should be abandoned for use for trans-femoral amputees.

Adolescent↗
PubMed2002

Clinical field-testing of ATLAS prosthetic system for trans-tibial amputees.

The ATLAS prosthetic system was tested on 81 trans-tibial amputees in two tropical areas and followed for about two years. At the conclusion 19% (15/81) had given up its use; mostly because of unsatisfactory socket fit, but in 7% (6/81) system related failures were the cause of non-compliance; mostly because of a shrieking noise from the shin-foot piece during use. System related failures were encountered in 62% (41/66) of users; the most serious threat to patient safety was fractures of the shank in 39% (26/66) and badly worn feet in 12% (8/66). With a failure rate of about 41% after one and a half years the ATLAS system is considered unacceptable for general use in trans-tibial amputees.

Adolescent↗
PubMed1999

Additional studies on the distribution of stresses during vertical compaction of gutta-percha in the root canal.

OBJECTIVE: This study was designed to investigate the effect of certain pathological alterations of the dental structures (diminishing bone support, internal resorption, root perforation, periapical lesion) on stress distribution during root canal filling procedures by the warm vertical compaction technique. DESIGN: The computer stress analyses were done for a maxillary canine tooth model which was based on dimensions recovered from a human cadaveric maxilla scanned by CT. METHODS: The finite element method was used to calculate the stresses generated during root canal filling procedures by warm vertical compaction technique. Patterns of stress distribution associated with various alterations in dental structures were investigated. For this purpose 60 cases were simulated. The hypothetical force of 10 N is taken as a unit representation. For other magnitudes of applied force, the corresponding stresses would be scaled directly because the calculations were made for linear materials. RESULTS AND CONCLUSION: It is found that, when diminishing bone support and internal resorption are concurrently simulated, a marked increase in stress magnitudes occur (maximum von Mises stress 5.37 N/mm2). However, these values still remain much below the most frequently reported tensile strength of dentine (50-100 N/mm2). If dentist's handwork is transformed into equivalent edge tractions on gutta-percha, then stresses in dentine, even when they are corrected for 3-kg applied force, appear to remain below fracture strengths of this material. This result leads us to conclude that when warm vertical compaction technique is skillfully performed and inadvertent undue force is not applied, a premature root fracture in a large rooted maxillary anterior tooth with straight root canal anatomy is not likely to occur, even for the unfavourable conditions simulated in our model. This result, like all results derived from modelling applications, is of course contingent upon agreement between the way in which the clinical operations are performed and the way in which they are mirrored for computer representation. We believe that the approach described here avoids the spurious stresses that have been reported in similar investigations.

Computer Simulation↗
PubMed1993

Multiprocessor and memory architecture of the neurocomputer SYNAPSE-1.

A general purpose neurocomputer, SYNAPSE-1, which exhibits a multiprocessor and memory architecture is presented. It offers wide flexibility with respect to neural algorithms and a speed-up factor of several orders of magnitude--including learning. The computational power is provided by a 2-dimensional systolic array of neural signal processors. Since the weights are stored outside these NSPs, memory size and processing power can be adapted individually to the application needs. A neural algorithms programming language, embedded in C(+2) has been defined for the user to cope with the neurocomputer. In a benchmark test, the prototype of SYNAPSE-1 was 8000 times as fast as a standard workstation.

Algorithms↗
PubMed1991

[Adverse side effects of amalgam? An interdisciplinary study].

In an interdisciplinary study starting 2.5 years ago patients with various symptoms, which they associate with amalgam fillings, were examined. According to the first results of this study with 50 patients, the Hg-concentration in urine does correlate with the amount of amalgam fillings before and after taking DMPS (2,3-Dimercapto-1-propane-sulfonic-acid), but with a maximum of 66.4 micrograms Hg (24 h urine) the amounts of mobilization measured were significantly below toxicologically critical limits. Only in 3 patients did the individual immunological values (CD4/8 ratio, antinuclear antibodies) by far exceed standard values. In one case an allergy to amalgam is suspected. 40% of the patients showed a pathological psychiatric status (neurosis, depression, etc.). Another quarter had psychological problems like alcoholism or drug abuse. There is no reason at the moment to reject amalgam as filling material either because of the measured Hg-concentrations or because of any immunological or allergological findings.

Adolescent↗
PubMed1990

Skin cleansing in health and disease.

Skin cleansing has to be considered as an important component of daily hygiene in normal skin and as an important part of therapy in diseased skin. The crucial point is the choice of the cleansing agent to be recommended as skin tolerance of detergents is sometimes low. The evaluation of cleansing products depends upon their cleansing action (detergent or adsorptive), on the general and specifically epidermal toxicity of the components, on the rinsability of the product, and on the amount and nature of the additives, e. g. perfume oils. The knowledge of all the above-mentioned points will help the cosmetic adviser as well as the dermatologist to make the right choice depending upon the actual condition of the skin.

Baths↗
PubMed1990

[Chances for the intraoral use of screen films?].

The development of film/screen combinations has reached a point where they can be used intraorally for many indications. Compared with the fastest non-screen films the dose can be reduced by the factor 8, at the moment. For a wide-spread clinical usage, however, practicable application techniques still have to be developed for the intraoral film/screen combination.

Humans↗
PubMed1989

[Occupational dermatoses: clinical picture, noxious compounds, prevention].

Various occupational substances may cause dermatological lesions. Toxic, toxic-degenerative and allergic eczemas have to be mentioned on the first hand. The prevention of dermatoses ranges among the most important tasks of occupational medicine. The first measure should be a minimization of the direct skin contact with dermatotoxic substances. Here, adequate cleaning products play an important part. --When working with potentially toxic substances, the use of protective devices must be recommended. There are two possibilities: wearing gloves or application of protective ointments. In both instances, numerous disadvantages have to be considered. The main point is the reduced quality of work. Recently, a foam product for external protection has been developed. Clinical experiments and first practical experiences permit the assumption that this foam product which forms a biphasic lattice in the outer layers of the stratum corneum may ameliorate the situation.

Dermatitis, Occupational↗
PubMed1989

[How can the male protect himself from HIV infection?].

HIV infection is primarily transmitted via white cells of the blood or sperm. The greatest risk of infection for the passive partner is anal intercourse with ejaculation. The only protection against this way of infection is the use of a special condom by the active partner. Heterosexual coitus carries only a less important risk of HIV infection for the man. Properly used, the condom protects both the man and his female partner against AIDS. In the case of condom failures (spillage, tears), this protection may by preserved through the use of a special condom coated with nonoxinol 9. Finally, in view of their increasing importance, modern condoms are discussed with regard to their production, quality and safety.

Contraceptive Devices, Male↗
PubMed1989

[The treatment of allergic diseases].

In allergies, causal and symptomatic treatments are possible. Among the causal measures, antigen elimination has to be mentioned on the first hand. If this is not possible (in pollinosis, in allergy to the house dust mite), hyposensitization is indicated. Effectiveness and undesirable actions of hyposensitization are discussed in detail. Glucocorticoids maybe used for the symptomatic relief of allergic symptoms. However, cautious use is advisable. In type I-allergies, histamine is the most important mediator. Therefore, inhibitors of mast cell degranulation and H1-blocking agents are the drugs of first choice. Non sedative acting compounds (astemizole, oxatomide, terfenadine) are preferred.

Bronchodilator Agents↗
PubMed1989

[Practically important allergies. An overview].

In this survey, the importance of the various allergic diseases in medical practice is outlined. Animal allergies which are on the increase and allergies against fungal spores are discussed in more detail as new data have been collected in recent years. In closing, some remarkes were made on professional allergic diseases.

Allergens↗