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Biomedical subjects

G Werner

Publications and source records attributed to G Werner.

At least 145 records · Page 8Linked to original sources

Cutaneous stimulus registration and information processing in the somesthetic cortex.

The author reviews the evidence that the acquisition of sequential tactile information and stereometric object identification by manual exploration is a process which is analogous to the scanning of visual scenes. The hypothesis that somatosensory and visual maps in the respective primary cortical projection areas are of the same analytical structure is argued. New experimental data documented in subhuman primates demonstrate that neural responses to cutaneous stimuli depend on situational factors and on behavior-controlling instructions conveyed over another sense modality and that as a result the redundancy of cutaneous stimulus encoding in the somesthetic cortex is reduced.

Afferent Pathways↗

[Development of a new testmethod for surface disinfection procedures. III. The impression method: influence of the test surface material and the types of microorganisms on the recovery rate (author's transl)].

The preceding test results appear to favour the impression method used for the testing of surface disinfection procedures. Further investigations were concerned with the selection of a suitable germ carrier. The high recovery rate of the bacteria and the invariably uniform quality of the germ carrier are the decisive criteria. Since a dependence on the type of germ was also to be expected, we checked Staph. aureus, Str. faecalis, E. coli, Kl. pneumoniae and P. aeruginosa for their behaviour on PVC, varnished wooden surfaces, V 2A, rough and smooth glass, resopal, ceramic tiles with dull and glazing finish as well as on plywood. The germ carriers were contaminated quantitatively, dried, sprayed with distilled water to stimulate disinfection and examined after they were allowed to react for a period of 6 hours. A set of 10 germ carriers was examined simultaneously with 10 Rodac impressions. The data were checked by variance analytical methods and evaluated on the mean (or median) values. It was found that while the initial germ number was kept equal OP tiles and V 2A steel produced the highest germ yield. Plywood proved largely unsuitable. Among the test germs, E. coli and Kl. pneumoniae had the lowest adhesion; it was inferior to that of staphylococci and pseudomonads. However, for these 4 germ types 3 impressions per germ carrier suffice for a reliable assessment based on computations. The yield amounts to more than 90 per cent. 94 per cent of the Streptococci were also recovered with 3 impressions, but the absolute germ quantity was low. The use of this type of germ can be recommended only with reservation.

Bacteriological Techniques↗

[Enzyme patterns in connective tissue proliferations (author's transl)].

In a series of benign or semimalignant connective tissue proliferations (4 desmoids, 1 recurrence of a dermatofibrosarcoma protuberans, 4 fibromas, 1 neurofibroma, 3 keloids, 3 Dupuytren's contractures) and a normal fascia for comparison the pattern of 18 enzymes from different metabolic pathways was investigated. It should be clarified whether alterations of the enzyme pattern wouldoccur, asthey are found in malignant tumours. The activity of most of the enzymes investigated increased about twofold in the latter of two extirpations (16 months interval) of a recurring desmoid. In the recurrence of a dermatofibrosarcoma protuberans and in a recurrance of a fibroma a remarkably high activity of glucose-6-phosphate dehydrogenase and pyruvate kinase was found. High activities of these enzymes are known to be characteristic of experimental tumours of animals and human malignant neoplasms. Therefore it is assumed that these differences from the normal patternof enzyme activity are related to recidivity and may be regarded as first signs of a deviation from benignity. Based on these results further studies haveto be done with the aim to find a biochemical tool for, evaluation and prognosis of the course of these diseases.

Dupuytren Contracture↗

Comparative autoradiographic and metabolic study of delta8- and delta9-tetrahydrocannabinol in the brain of the marmoset Callithrix jacchus.

The label distribution in the brain of the marmoset Callithrix jacchus following intravenous application of radioactively labeled delta8-tetrahydrocannabinol (delta8-THC) and delta9-THC is investigated by autoradiographic technique. Accumulations of label are observed in nuclei concerned with motor function, in the optic and acoustic pathways, and a few other structures. Of the two hydroxylated isomeres which were shown to be equally psychoactive the brain concentration of 11-OH-delta9-THC was found to be about 3 times higher as compared with 11-OH-delta8 THC, which may explain why delta9-THC is more potent than delta8-THC. More than 90% of the radioactivity found in the brain can be attributed to the THCs and their 11-hydroxylated isomeres. Polar metabolites are almost completely absent from the brain.

Animals↗

[Autoradiographic studies on the distribution of 3H-pyrithioxine in monkey and mouse (author's transl)].

Monkeys and mice received oral and i.p. doses of 3H-labelled pyritinoldihydrochloridemonohydrate (3H-pyrithioxine; Encephabol) and the distribution of radioactivity in the brain and in other organs was investigated by autoradiography. The heaviest label accumulation was present in the pituitary gland. In the monkey the distribution of radioactivity in the brain and in the submandibular gland was different from the distribution found in these organs in the mouse, which may be attributed to the different radioactive metabolites of pyrithioxine produced by the two animal species. Prior to elimination from the body pyrithioxine was completely transformed into metabolites.

Administration, Oral↗

Metabolism and autoradiographic distribution of delta-8- and delta-9-tetrahydrocannabinol in some organs of the monkey Callithrix jacchus.

Metabolism and autoradiographic distribution of the two isomeric tetrahydrocannabinols, (2,4-14-C)-delta-8-THC and (2,4-14-C)-delta-9-THC, were studied in the marmoset Callithrix jacchus. Of the two cannabinoids, delta-8-THC had a slower initial rate of biotransformation to the psychopharmacologically more potent 11-hydroxylated metabolite. This may explain the minor psychopharmacological activity of the delta-8-isomer. In glandular tissues an accumulation of unchanged delta-9-THC was observed. Autoradiography revealed characteristic label distributions in some organs 30 min after the administration of the drugs. This labelling pattern was found to be changed after a 6-hr incorporation period. The autoradiographic distribution of delta-8 and delta-9-THC appeared to be identical.

Adrenal Glands↗

[A comparison of the results of 4 national methods for the evaluation of disinfectants in 2 laboratories (author's transl)].

At present the testing and assessment of disinfectants is carried out according to different methods in different countries. The result of this is that certain preparations or concentrations are allowed for use in some countries while they are not in neighbouring countries. A study was carried out jointly at two universities with the object of testing the reproducibility of these methods and standardizing them. Furthermore, an attempt was to be made to arrive at common test methods. In 2 labortories (A,B) we tested and compared the disinfectant activity of three disinfectant standards (phenol, aldehyde, iodophor) against Staphylococcus aureus and Pseudomonas aeruginosa (1) in the suspension test according to the "Richtlinien für die Prüfung chemischer Desinfektionsmittel" (Directions governing the testing of chemical disinfectants) of the DGHM, (2) in the suspension test of the "Dutch Commission for Phytopharmacy," (3) according to the "Use-Dilution Method" of the A.O.A.C. and (4) in the capacity test according to KELSEY and SYKES. Every individual test was repeated ten times. In addition we determined the reproducibility of the results by repeating the tests several times with one and the same culture and with different cultures (on different days). The exact method is described elsewhere (7). The statistical evaluation of the mean values (Tables 1,3,5 and 7) and variances (Tables 2,4,6 and 8) leads to the following findings: The results obtained with the various methods depend on the lab. technique and were specific to the germs and preparations tested. The reproducibility was best in the DGHM suspension test and the capacity test according to KELSEY and SYKES; the mean values of the two laboratories were closest for the Dutch test of the Commission of Phytopharmacy. The greatest mean value differences and scatter were observed with the A.O.A.C. "Use-Dilution Method." The conclusion of this investigation is that for the preliminary testing of disinfectants a method should be recommended which enables the determination of the acturl germ count reduction after varying periods of action and with well-defined organic challenge. In order to assess the disinfectant action, however, such a test - which answers most of our questions and has optimum reproducibility - must be supplemented by main tests which simulate practical conditions as near as possible.

Aldehydes↗