Mucin-producing bronchioloalveolar-cell carcinoma. With special reference to a characteristic structure revealed by phosphotungstic acid-hematoxylin staining

In four cases of bronchioloalveolar-cell carcinoma of the mucin-producing type, the cells were characterized electron microscopically by cored microvilli seen on the free surface of the tumor cells, structures that corresponded well to the phosphotungstic acid-hematoxylin (PTAH) stained structures seen by light microscopy in histologic specimens. The exfoliative cytology specimens contained corresponding PTAH-stained structures on the cell surfaces, namely, a prominent cell membrane with a "beaded" or "peg-like" configuration and, in places, a "feathery" nature, findings quite dissimilar to the surfaces of other well-differentiated adenocarcinoma cells. The cytologic specimens also exhibited characteristic nuclear indentations and tightly connected cell groupings. These results indicate the existence of a type of bronchioloalveolar-cell carcinoma not derived from type II alveolar epithelial cells or Clara cells.     

Mechanisms of homocysteine neurotoxicity in neurodegenerative diseases with special reference to dementia

Mild to moderate hyperhomocysteinemia is a risk factor for neurodegenerative diseases. Human studies suggest that homocysteine (Hcy) plays a role in brain damage, cognitive and memory decline. Numerous studies in recent years investigated the role of Hcy as a cause of brain damage. Hcy itself or folate and vitamin B12 deficiency can cause disturbed methylation and/or redox potentials, thus promoting calcium influx, amyloid and tau protein accumulation, apoptosis, and neuronal death. The Hcy effect may also be mediated by activating the N-methyl-D-aspartate receptor subtype. Numerous neurotoxic effects of Hcy can be blocked by folate, glutamate receptor antagonists, or various antioxidants. This review describes the most important mechanisms of Hcy neurotoxicity and pharmacological agents known to reverse Hcy effects.     

Current usage of nomenclature for parasitic diseases, with special reference to those involving arthropods

Terminological confusion has been aggravated by efforts to develop a standardized nomenclature for parasitic diseases (SNOPAD) arising from the proposal by Kassai et al., 1988) for a standardized nomenclature of animal diseases (SNOAPAD). To restabilize international nomenclature of parasitic diseases it is recommended that, whenever appropriate, names should follow the 'International Nomenclature of Diseases' (IND) compiled by the Council for International Organizations for Medical Sciences (CIOMS/WHO, 1987). For diseases not included in IND, familiarity should guide the choice of name: traditional English language names of diseases should be preferred, e.g. 'malaria', 'scabies' or, for parasitic diseases having no traditional name, the taxonomic name of the causative organism should be applied, e.g. 'Brugia timori microfilaraemia'; 'Plasmodium malariae infection'; 'Simulium allergy'--instead of the generic derivatives proposed by SNOPAD, i.e. brugiosis, plasmodiosis and simuliidosis, respectively. For names of new diseases or those rarely mentioned, the suffix -osis would normally take precedence. Generally, the name of choice for any disease in any language should be the vernacular term, with commonest English usage preferred for international communication, and publications should include synonyms in the list of keywords.     

Occurrence and distribution of fruiting body-forming myxobacteria in Siebengebirge. Comparative studies with special reference to characteristic biotypes]

In the region of the "Siebengebirge" near Bonn, six characteristic biotopes were studied with respect to the occurrence of fruiting body forming myxobacteria. 23 different species, belonging to the 8 known genera, were found. The number of species in the respective biotopes varied between 6 and 17, the average numbers of species per sampling area were between 2.1 and 10.0. 15 species were found on dung pellets of wild living herbivorous mammals. Deciduous forest soils contained 13 species in spring, 17 species in autumn. Rock coverings contained 14, creek slopes 16, bark of living trees 9, and rotting wood 16 fruiting myxobacterial species. Myxococcus fulvus, Myxococcus coralloides and Archangium gephyra occurred in all biotops studied. The rare species were Melittangium boletus, Polyangium vitellinum, Stigmatella aurantiaca, and Chondramyces apiculatus. The composition of the myxobacterial flora depends on ecological factors (kind of dung pellets, rock, bark and pH). The ecological influences upon the distribution are discussed.