In vitro cultures of higher plants and fungi as a potential source of bioactive metabolites.

The review presents the results of investigations conducted at the Chair of Pharmaceutical Botany, Collegium Medicum, Jagiellonian University, which demonstrated a prospects to obtain biologically active metabolites representative of many chemical groups (furanocoumarins, polysaccharides and lectins, indole compounds, carotenoids) in in vitro cultures of both higher plants and higher fungi (Macromycetes) (mycelial cultures). These cultures can be a potential, rich, new source of metabolites.

Cerebellar atrophy in Alzheimer's disease-clinicopathological correlations.

Morphometry of the cerebellum of 11 subjects who died in the severe, final stage of Alzheimer's disease (AD) and of five age-matched subjects without dementia revealed significant atrophy in the AD group, with a decrease in the volume of the molecular layer by 24% and of the granular layer by 22% in comparison with controls. The 32% decrease in the total number of Purkinje cells that was observed correlates with the atrophy of the molecular layer, whereas the 30% reduction in the total number of granule cells correlates with the atrophy of the molecular and granular layers. A unique pattern of Alzheimer-type pathology was observed in the cerebellum: (1) there were no neurofibrillary changes in the cerebellum of either the control or the AD subjects, (2) there was almost the same extent of leptomeningeal and cortical amyloid angiopathy in the normal aged subjects and in the AD patients, and (3) the presence of plaques was noted in the AD group, but not in the control group. This pattern of pathology suggests that two factors might be considered in the etiopathogenesis of cerebellar atrophy: (1) transneuronal degeneration and neuronal loss resulting from primary pathologic changes in cerebral structures and (2) parenchymal cerebellar ss-amyloidosis. The correlation between the temporal duration of AD and both the decrease of the total number of granule cells (r=0.86, p<0.01) and the volumetric loss of the molecular (r=0.73, p<0.05) and granular (r=0.93, p<0.001) layers of the cerebellar cortex indicates that these cerebellar atrophic changes are likely to be related to the basic pathologic process of AD. Similarly, the correlation between the most complex parameter the atrophy of the cerebellar cortex and the Functional Assessment Staging (FAST) measure of the clinical severity of AD at the time of demise (r=0.63, p<0.05) as well as with the duration of AD (r=0.78, p<0.01) indicates that cerebellar pathology, when viewed holistically, evolves continuously in association with clinical changes throughout the clinically manifest course of AD.

Metal cations defibrillize the amyloid beta-protein fibrils.

Amyloid beta-protein (A beta) is the major constituent of amyloid fibrils composing beta-amyloid plaques and cerebrovascular amyloid in Alzheimer's disease (AD). We studied the effect of metal cations on preformed fibrils of synthetic A beta by Thioflavin T (ThT) fluorescence spectroscopy and electronmicroscopy (EM) in negative staining. The amount of cross beta-pleated sheet structure of A beta 1-40 fibrils was found to decrease by metal cations in a concentration-dependent manner as measured by ThT fluorescence spectroscopy. The order of defibrillization of A beta 1-40 fibrils by metal cations was: Ca2+ and Zn2+ (IC50 = 100 microM) > Mg3+ (IC50 = 300 microM) > Al3+ (IC50 = 1.1 mM). EM analysis in negative staining showed that A beta 1-40 fibrils in the absence of cations were organized in a fine network with a little or no amorphous material. The addition of Ca2+, Mg2+, and Zn2+ to preformed A beta 1-40 fibrils defibrillized the fibrils or converted them into short rods or to amorphous material. Al3+ was less effective, and reduced the fibril network by about 80% of that in the absence of any metal cation. Studies with A beta 1-42 showed that this peptide forms more dense network of fibrils as compared to A beta 1-40. Both ThT fluorescence spectroscopy and EM showed that similar to A beta 1-40, A beta 1-42 fibrils are also defibrillized in the presence of millimolar concentrations of Ca2+. These studies suggest that metal cations can defibrillize the fibrils of synthetic A beta.

Familial dysmyelination in a Long Evans rat mutant.

Tremors were observed in 15 Long Evans rats beginning at 10 to 12 days of age. These were followed by progressively worsening ataxia, hind limb paresis, episodes of immobility, and seizures by 5 to 14 weeks. Gross lesions were not observed at necropsy in rats euthanized and perfused at 4 to 16 weeks of age. Neurohistologic examination revealed dysmyelination in the central nervous system. Astrogliosis in the white matter with marked increase of expression of the glial fibrillary acid protein marker was accompanied by diffuse microgliosis. Scattered glial cells, interpreted to be oligodendrocytes, contained minute periodic acid-Schiff-positive cytoplasmic granules. Large mineralized periodic acid-Schiff-positive and laminated structures were observed in the cerebellar white matter, midbrain, and thalamus of rats over 6 weeks old. Neuronal degeneration and loss was evident in the cortex, hippocampus, and midbrain. Large axonal spheroids were found in the ventral and lateral funiculi of the spinal cord. An ultrastructural study of four affected rats revealed an almost complete absence of myelinated axons and normal sheaths, and degeneration and necrosis of oligodendrocytes. The Long Evans shaker rat represents a novel myelin mutant with a remarkable survival period and appears to have an autosomal recessive mode of inheritance.