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Biomedical subjects

G Walter

Publications and source records attributed to G Walter.

265 records · Page 15Linked to original sources
PubMedDate not supplied

Effects of lipoic acid in hexacarbon-induced neuropathy.

The effects of lipoic acid on hexacarbon neurotoxicity in rats were investigated. Rats were exposed by inhalation to n-hexane for 24 hours/day, 7 days/week, up to a total period of 9 weeks. Eight animals were exposed to 700 ppm n-hexane only, and eight animals were exposed to 700 ppm n-hexane and additionally received 100 mumol/kg lipoic acid PO daily. Clinical status of the animals was evaluated by examination of general condition, motor performance tests and neurophysiological measurements of caudal nerve motor conduction velocity. Results showed that animals exposed to 700 ppm n-hexane developed severe motor neuropathy leading to paralysis by the 6th week. Motor distal latencies of these animals were severely prolonged. In contrast, in animals treated with lipoic acid the onset of motor neuropathy was delayed for approximately 3 weeks as could be demonstrated by motor performance tests and measurements of motor distal latencies.

Action Potentials↗
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Tapping allergen repertoires by advanced cloning technologies.

BACKGROUND: Complex allergenic sources such as moulds, foods and mites contain complex panels of IgE-binding molecules which need to be cloned, produced and characterized in order to mimic the entire allergenicity of whole extracts reconstituted by mixing single standardized recombinant allergens. METHODS: Phage surface display of cDNA libraries selectively enriched for allergen-expressing clones using IgE from allergic patients allows rapid isolation of large panels of allergens. For the characterization of all different clones present in enriched cDNA libraries in a fast and cost-effective way, high-throughput screening technology is required. RESULTS: The combination of selective enrichment of cDNA libraries based on biopanning against serum IgE from sensitized patients and automated robot technology for picking and high-density gridding of clones onto filter membranes, followed by hybridization, enables fast identification of all the different clones present in an enriched library. The consequent application of selective enrichment and robotic-based screening allows, within weeks, cloning and characterization of the whole allergenic repertoire of any organisms. CONCLUSIONS: Robotic-based high-throughput screening of clones selected for IgE-binding capacity from phage surface-displayed cDNA libraries of Aspergillus fumigatus, Cladosporium herbarum, Coprinus comatus, Malassezia furfur, peanut and human lung tissue allowed rapid characterization of 81, 28, 37, 27, 8 and 151 different sequences, respectively. All these cDNAs bear a high probability to encode allergens derived from the respective allergenic source.

Allergens↗
PubMedDate not supplied

New aspects of itch pathophysiology: component analysis of atopic itch using the 'Eppendorf Itch Questionnaire'.

Itch represents a leading symptom in dermatological practice with many psychophysiological aspects. Instruments for qualitative registration of these central nervous factors and evaluation of therapeutic measures are still missing. We analyzed in detail the subjective itch sensation in 108 patients with acute atopic eczema with a new questionnaire developed in analogy to the McGill pain questionnaire. The descriptors with the highest load in atopic itch and the most frequent reaction patterns in atopic eczema patients were identified. Itch intensity (mean VAS 62%) and eczema severity (SCORAD mean 41 points) showed a different frequency distribution pattern with a correlation of r = 0.33 (p < 0.05). Principal component analysis of the itch questionnaire data was performed and compared with the standardized SCORAD severity index for the patients with atopic eczema. Three main factors of atopic itch explained 58% of the total variance: (1) 'suffering' (correlation with SCORAD, r = 0.6); (2) 'phasic intensity' (correlation with SCORAD, r = 0.4), and (3) 'ecstatic' component (associated with certain active reaction patterns). In conclusion, the complete description of itch has to consider different factors, which may be described on a more general level by three main components. Two of these are correlated with objective criteria of disease activity.

Adolescent↗
PubMedDate not supplied

Hypericum perforatum (St John's wort) in depression: pest or blessing?

St John's wort (SJW) was introduced into Australia during the 1880s for medicinal purposes, but was subsequently declared a noxious weed. There is now a resurgence of interest in the therapeutic properties of this herb. In particular, use of SJW as an antidepressant has increased in recent months owing to reports of its effectiveness and safety. Nevertheless, the controlled trials available have limitations. Increasing use of SJW in the community poses a variety of questions. For example, should medical practitioners become more knowledgeable about the effects and interactions of alternative remedies? What are the ethical and medical implications of "antidepressant" prescribing by non-medical persons? Who is to fund further research and treatment studies? How can quality of SJW preparations be guaranteed?

Adult↗
PubMedDate not supplied

From Karrawingi the emu to Care factor zero. Mental health issues in contemporary Australian adolescent literature.

OBJECTIVE: To examine the depiction of mental health issues in contemporary Australian adolescent literature. This material might influence teenagers' understanding of mental illness and their willingness to seek help, and may provide insights into societal attitudes towards adolescents and the psychiatric problems encountered in this age group. DESIGN: Systematic examination of a sample of 94 books, the "Notable Texts" in the "Older Child" category of the Children's Book Council of Australia Awards for the years 1996, 1997 and 1998. MAIN OUTCOME MEASURES: Number of works referring to psychiatry; characters who experienced trauma, loss, psychiatric symptoms, qualified for a psychiatric diagnosis, exhibited suicidal behaviour or sought help; and the nature of treatments given. RESULTS: There was reference to psychiatry in over two-thirds of the works. In these books the image of psychiatry was generally negative or mixed. Most adolescent characters suffered major losses. Two-fifths of characters met criteria for a psychiatric diagnosis. The outcome for characters who satisfied criteria for a psychiatric diagnosis was more negative than those without. Of the 10 characters in the sample who committed suicide, eight had a psychiatric disorder. CONCLUSIONS: Psychiatric themes are a major component of the Australian teenage novel. Young people in contemporary Australian teenage literature are beset with trauma, loss and psychiatric disorders. Even when help is obtained, the outcome is seldom positive. This nihilistic view may increase hopelessness and pose a barrier for teenagers seeking help.

Adolescent↗
PubMedDate not supplied

[Phagocytic activity of granulocytes after UV-irradiation].

The effect of UV-irradiation on three functions of human isolated granulocytes (viability, phagocyte activity and capacity to reduce nitrotetrazolium blue) was investigated. The phagocytosis appeared to be the most sensitive function. The number of phagocytic cells was decreased under UV-doses as low as 0.63 kJ.m-2. Cell lethality was increased under UV-doses 4.32 kJ.m-2 and higher. The capacity to reduce nitrotetrazolium blue was uneffected even at the dose as high as 10.17 kJ.m-2.

Granulocytes↗
PubMedDate not supplied

Clinical data on three cases of occupationally induced PCB-intoxication.

Since the ban of PCBs at the end of the 1970s, extensive measures have been undertaken in Germany to dispose of PCB contaminated transformers. We report on three patients with considerable skin exposure to PCBs, in particular to Clophen A 30, while repairing or dismounting transformers. The periods of exposure range from 4 and 5 to 20 years. All patients presented with distal-symmetrical sensorimotor polyneuropathy as well as encephalopathy. In one of the cases, the neuropathy and encephalopathy progressed for a period of over 8 years after termination of exposure. In the two other cases the neurological deficits persisted over an observed period of 2-3 years. The reported clinical results may suggest that the long half-life of Clophen and its accumulation in fatty tissue can lead to persistence of PNS and CNS impairment long after the period of exposure.

Aged↗
PubMedDate not supplied

Neurological investigations in 23 cases of pyrethroid intoxication reported to the German Federal Health Office.

In 1993, 64 cases of chronic pyrethroid intoxication were reported to the Federal Health Office in Germany. Shortly afterwards the media spoke of thousands of cases of pyrethroid intoxication in homes. 23 of the persons reported were examined in a neurological department on an inpatient basis using clinical neurological, neuroradiological and laboratory investigations, including the examination of pyrethroid values in blood and urine. The pyrethroid exposure involved carpets, moth killers, pesticide sprays and wood preservatives. Nine of the cases presented with severe somatic or psychiatric disorders with completely different clinical diagnoses, such as pituitary tumor, radiogenic lumbosacral plexus paralysis, Guillain- Barré syndrome, spinal muscular atrophy, with no plausible relationship to exposure. Eight cases presented with multiple chemical sensitivity syndrome (MCS) and normal somatic findings. In six of the cases, a causal link between acute complaints and pyrethroid exposure could be established or not ruled out. There was, however, not a single case in which evidence for irreversible PNS or CNS lesions could be found.

Adult↗