Hierarchy within human SI: supporting data from cytochrome oxidase, acetylcholinesterase and NADPH-diaphorase staining patterns.

The human primary somatosensory cortex consists of four cytoarchitectonic subdivisions (3a, 3b, 1 and 2) that are likely to contain distinct somatosensory representations. The intraareal organization of these areas as well as that of the primary motor cortex (area 4) has been analyzed using histochemical stains of cytochrome oxidase, acetylcholinesterase and NADPH-diaphorase activity in normal human brains. Cytochrome oxidase activity was revealed in individual cortical neurons and neuropil. Areas 4, 3a and 3b were on average darker than areas 1 and 2. The laminar distribution of cytochrome oxidase activity varied in different areas. A prominent dark band was present in layers IV and lower III in areas 3a and 3b and in layer III in areas 1, 2 and 4. Acetylcholinesterase staining revealed fibers and pyramidal cells in layers III and V; stained layer III pyramids were rare in areas 3a and 3b and numerous in areas 1, 2 and 4. NADPH-diaphorase positive elements included Golgi-like stained non-pyramidal neurons and Nissl-like stained pyramidal neurons; the former were found, in small numbers, in layer II of areas 4, 3a, 3b and 1, and the latter in layers III and V of areas 4 and 3a and in layer V of areas 1 and 2. The dark cytochrome oxidase staining of layer IV and the paucity of acetylcholinesterase positive pyramids in areas 3a and 3b resemble the pattern found in primary visual and auditory areas, whereas the dark cytochrome oxidase staining in layer III and abundance of acetylcholinesterase positive pyramids in areas 1 and 2 that of association areas. These results suggest that the four areas included in human SI constitute hierarchical stages of cortical processing, with 3a and 3b corresponding to primary and 1 and 2 to secondary areas.

Thalamic projections of the fusiform gyrus in man.

Previous retrograde degeneration studies have shown that human extrastriate visual cortex receives projections from the pulvinar, but their precise topographical organization remained unknown. We report on the distribution of thalamic projections originating in the fusiform gyrus, as studied with the Nauta method for anterogradely degenerating axons, in a case of right fusiform gyrus infarction. Ipsilaterally to the lesion, high density of afferents was found in the inferior pulvinar nucleus and a low density in the medial pulvinar nucleus as well as in the postero-inferior part of the reticular nucleus; no degenerating fibres were found in the lateral geniculate body. Degenerating axons were completely absent in the contralateral thalamus. Thus, there is a precise topographic relationship between parts of the extrastriate cortex and the pulvinar, suggesting segregated thalamocortical pathways for different parts of the extrastriate cortex. As in nonhuman primates, the human inferior temporal cortex has no direct output to the lateral geniculate body.

The pathological process. V. Experimental modelling in pathology: general theoretical problems.

The theoretical analysis of the characteristic features of pathological processes is being continued with the experimental modelling of the pathological process, with emphasis on gnoseological and heuristic aims. The paper discusses: the compulsory working hypothesis which includes the known and the probable data resulting from the observation of phenomena, the qualities and value of the experimentation for the verification of the working hypothesis, the general features of the experimental modelling in pathology and its purposes, the types of experimental models (simple, two times perturbing and complex) with exemplification and discussion of qualities and limits, the general evaluation and limits of experimental models, the practical elaboration of experimental models with emphasis on the main rational operations, like the choice of animals, of the ways of administration of perturbing agents, of experimental and control lots, of sacrification modalities, as well as the relevance of the experimental results for enlarging the knowledge of the pathological process investigated.

The pathological process. III(IV). Cellular population systems as substrates of pathological processes: structure, reactivity, dynamics and basic lesions.

This fourth paper dealt with the analysis of cellular population systems as the main substrates of pathological processes. The analysis pointed out the reactivity of these systems, their histogenesis and dynamics, their cellular composition and reactional capacity of composing cells, the relations between different groups of cells forming the system (intrasystemic relationships), those between proliferation and differentiation-maturation, the multifactorial determinism of proliferation, differentiation, maturation and mobilization of the cells composing the system. The analysis of basic lesions of cellular population systems (cellular hypertrophy, cell hyperplasia, metaplasia and neoplastic transformation) completed this dynamic investigation.

The pathological process. II(III). Lesional sequentiality and its multifactorial determining: structure and dynamics of factor ensembles.

The dynamic and structural analysis of pathological processes points out their multifactorial determining, the importance of the intrinsic conditioning, the existence of a lesional sequentiality, exemplified by the chain of lesional sequences, morphologically different, the intersequential relations of cohesive and propelling type, and the discontinuity in the progress from one lesional sequence to another. Factor ensembles, ensuring and governing the start of the process and the transition from a lesional sequence to another, were analysed in point of structure, composition, role of substrates, dynamics of ensembles, roles played by ensemble components (cohesive, propelling role).

Lung pathogenesis. VIII. Relationships between alveolar surfactant disorders and development of lung diseases.

The new data concerning the structure and dynamics of the alveolar surfactant, its phospholipid and apoprotein components and their synthesis, storage and secretion by the large granular alveolocytes, the formation and disconnection of lipoprotein complexes, their disorders and pathological relationships were analysed in order to discern the possibility of a more or less important pathogenetic role in the onset and development of lung diseases. Sometimes, surfactant disorders appeared as epiphenomena, like in pulmonary edemas; at other times, they behaved as a turn plate enhancing and centering the development of alveolar lipoproteinosis, microlithiasis alveolaris, hyaline membrane disease of newborns and the adult respiratory distress syndrome. Focusing the pathogenesis on the surfactant disorders and on their causes, a unification of mechanisms became possible with the increase in complexity of processes by the intervention of other complicating factors, mainly the self-perpetuating ones.

Histopathology of tumorous ribs: a review of 130 cases.

There were studied histopathologically 130 tumorous ribs out of 167 tumoral processes of the thoracal wall (77 per cent) and representing about 2 per cent of all the neoplasms studied between 1949 and 1984. There were distinguished 50 malignant primary tumors (Ewing's sarcomas, Parker-Jackson's reticulosarcomas, endotheliosarcomas, low differentiated myelosarcomas and myelomas, osteogenic sarcomas, chondro- and osteochondrosarcomas, and fibrosarcomas), 45 secondary (metastatic) malignant tumors of ribs out of which 32 (75 per cent) originated from lung cancers, and 35 benign lesions (osteoclastomas, chondromas and osteochondromas, fibromas and osteofibromas, eosinocytic histiocytomas, and various osteodystrophies). Morphological differentiating criteria were discussed for each group. There were analysed, when possible, the ways of rib involvement by neighbouring processes, especially the periosteum relationships with the soft tissues of the thoracal wall and with vessels and pleura. Some histogenetic problems were also emphasized.