Cell cultures were derived from adult human brain biopsies [from cortical gray (cultures 9-HB-G and 33-HB-G) and white (culture 14-HB-W) and stroke-injured white matter (culture 33-HB-IW)]. The morphology and growth rate of cultured cells were examined and correlated with the presence of vimentin and glial fibrillary acidic protein (GFAP). The cultures from various brain matters differed in cell morphology and rate of growth but not in GFAP and vimentin staining. Cells of primary and rapidly proliferating cultures were GFAP-negative and vimentin-positive. Spontaneous growth deceleration occurred in culture 14-HB-W within passages 5 to 10 and in cultures 9-HB-G, 33-HB-G, and 33-HB-W within passages 17 to 20. This deceleration, as well as the successive complete growth arrest, were accompanied by an appearance of GFAP-positive cells and an elevated intensity for vimentin staining. We propose that GFAP-positive astrocytes originate from glial precursor cells that migrate from the explants and differentiate under prolonged subcultivation.

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Glial fibrillary acidic protein (GFAP) is an intermediate filament protein considered to be the best astroglial marker. However, the predominant cell population in adult human brain tissue cultures does not express GFAP; these cells have been termed "glia-like" cells. The basic question about histological origin of adult human brain cultures remains unanswered. Some authors showed that "glia-like" cells in adult human brain cultures might be of non-glial origin. We examined primary explant tissue cultures derived from 70 adult human brain biopsies. Within first 5-10 days approximately 5-10% of the small explants became attached. Outgrowing cells were mostly flat cells. These cells formed confluent layer over 3-6 weeks in culture. At confluence the cultures contained 2-5% of microglial cells, 0.1% GFAP-positive astrocytes, less than 0.01% oligodendrocytes and 95-98% GFAP-negative "glia-like" cells. This population of flat "glia-like" cells was positively stained for vimentin, fibronectin, and 20-30% of these cells stained for nestin. Our findings revealed that 1 mM dibutyryl-cAMP addition, in serum free conditions, induced a reversible stellation in 5-10% of the flat "glia-like" cells but did not induce the expression of GFAP or nestin in morphologically changed stellate cells. These results demonstrate that "glia-like" cells in primary adult human brain cultures constitute heterogeneous cell populations albeit with similar morphological features. Two distinct subpopulations have been shown: (i) the one immunostained for nestin; and (ii) the other reactive for dibutyryl-cAMP treatment.

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The presence of well developed appendices in some animals when compared to humans has led to speculation that appendix is a vestigial organ. Increasing number of studies have revealed that the appendix serves as an important organ in humans. The function of animal appendix, and the differences between species remain poorly understood. In this study we examined human myenteric plexus and compared them with animal studies. Appendices were obtained from five young adults in which the appendix was found to be normal after removal. Fixed appendix cryosections were examined by immunofluorescence methods using neuronal marker antibodies to neurofilaments and beta III tubulin. Both antibodies stained myenteric ganglia which were arranged in an apparently irregular pattern in human appendix wall. We observed unexpected localization of myenteric ganglia in the subserosa often accompanied by rarely occurring ganglia in the longitudinal muscle layer. These ganglia were of different sizes and shapes and unequally distributed under a thin layer of serosa. Our findings raise many questions about the possible role of irregular and atypical myenteric ganglia localization in relation to altered motility and subsequent pathogenesis of the appendix in inflammatory disease in humans. On the other hand, studies of the literature have revealed simplicity in the organization of myenteric plexus, e.g., in well-developed rabbit appendix. In addition, appendicitis in animals is restricted to in apes with similarly shaped appendix to humans.