Journal of submicroscopic cytology and pathology最新文献

Purkinje dendritic spines (Pds) of mouse cerebellar cortex were examined by field emission scanning electron microscopy (FESEM) and by transmission electron microscopy (TEM) using ultrathin sections and freeze-etching replicas, to study their three-dimensional features and intramembrane morphology. FESEM showed unattached mushroom-type, elongated and lanceolate Pds separated by 100-500 nm on the dendritic shaft surface. High resolution FESEM showed 25-50 nm globular subunits at the spine postsynaptic density corresponding to the localization of postsynaptic proteins and/or postsynaptic receptors. TEM images of ultrathin sections showed gem-like, mushroom-shaped, lanceolate and neckless or stubby spines. Freeze etching replicas exposed postsynaptic intramembrane particles that can be correlated with the globular subunits observed at high resolution FESEM. Parallel and climbing fiber endings were observed making asymmetric synaptic contacts with the Pds heads. Simultaneous contacts with the necks and heads were also found. The variety of Pds shapes were interpreted as spine conformational changes related with spine dynamic, and spine plasticity.

In the present investigation we studied the effect of naproxen, a non-steroidal anti-inflammatory drug used for the treatment of rheumatic disease, on the synthesis of the lepidotrichial matrix of the tail fin of the teleost fish Cyprinus carpio (carp) during the regeneration process. The lepidotrichial synthesis was observed by standard and polarized light microscopy and by transmission electron microscopy. In general, naproxen at the dose used in the present study did not affect the organization of the extracellular matrix components and the mineralization of the fundamental substance of the lepidotrichia during the process of tail fin regeneration. Since the effect of naproxen, as well as of other non-steroidal anti-inflammatory drugs, depends on the dose used, the route of administration and the metabolism of the animal in which the drug is being tested, higher doses of the drug may perhaps delay or even fully inhibit this process, possibly also provoke disorganization of the lepidotrichial matrix.

Tight junctions are regarded as the primary anatomical structure responsible for the blood-brain barrier (BBB). The molecular components that have been defined include ZO-1, a peripheral membrane protein associated with the cytoplasmic surface of the tight junction in epithelial and endothelial cells. It has been localized to the points of membrane contact with the fibrils seen by freeze-fracture. Examination of passaged endothelial cells with freeze-fracture failed to locate the intramembrane specializations associated with tight junctions. For this reason, immunocytochemistry and freeze-fracture were used to study the correlation of ZO-1 expression with the presence of tight junctions in bovine brain and aorta endothelial cells. Indirect immunofluorescence analysis showed ZO-1 to be localized at sites of cell-cell contact. Images of freeze-fractured sites of endothelial cell-cell contacts in identical passage numbers did not display characteristic tight junctions. When bovine aorta endothelial cells were cultured in astrocyte-conditioned medium on a complete extracellular matrix, platinum replicas displayed profiles of tight junctions. The elements of tight junctions were arranged as parallel ridges which displayed free ends. The immunofluorescence staining of ZO-1 was identical to that obtained on the endothelial cells that displayed no tight junction profiles. These results suggest that ZO-1 may be present at putative junction-containing sites before the junctional structures appear in the surface membrane. Therefore, ZO-1 expression does not a priori reflect assembly of the tight junctions identified by freeze-fracture.

The structural pathology of dendritic processes has been examined in 38 patients with clinical diagnosis of brain trauma, brain tumours and congenital malformations. Cortical biopsies of frontal, parietal, temporal and occipital cortex were conventionally processed for transmission electron microscopy. Isolated ultrathin sections and montages of electron micrographs were used to trace the intracortical dendritic course. Swollen and beaded dendrites were observed in all cases examined, which exhibited fragmentation of limiting plasma membrane and cytoskeletal structures. The swollen dendrites showed vacuolization, dense residual bodies, enlarged rough and smooth endoplasmic reticulum, edematous clear and dark mitochondria, a decreased synaptic density of shaft synapses, edematous and dystrophic changes of spine apparatus and a partial loss of dendritic spines. A wide variety of dendritic spine shapes were observed: mushroom-type, stubby, gem-like filiform spine, and megaspine, considered as spine dysgenesis in the congenital malformations and spine pathology and spine plasticity in brain traumatic injuries and brain tumours. The multifactorial processes associated with brain edema and brain ischemia, such as calcium overload, activation of calcium-dependent proteolytic enzymes, protein aggregation, glutamate-induced neurotoxicity, release of lysosomal enzymes, deficit of ATP, stress oxidative and lipid peroxidation have been considered in relation with the pathological dendritic changes. Dendrotoxicity due to brain edema and brain ischemia seems to be the fundamental pathogenetic mechanism.

Observation by SEM of the carapace microstructure of crabs showed, in the past, numerous differences at a specific level (i.e. in the genus Ebalia and Liocarcinus) as described by Spanò et al. (1995, 1999). The aim of this study is to describe the carapace micromorphology of some crab species of very different genera and species. A critical analysis of ecological data and morphological parameters is carried out in order to determine if the differences have adaptive significance.

Neuropeptides were used in experiments to assess their effects on planarian cells. Intact and decapitated planarians exposed to 10(-6) M neuropeptides for two days were examined electron microscopically and quantitative changes in the nuclear pores and chromatoid bodies in various types of cells were ascertained. The data clearly indicated the diversity of effects produced in planarian cells by neuropeptide treatments. The number of nuclear pores increased considerably in each cell type treated with neuropeptides. In particular, the effects of neuropeptides were strongest in differentiating cells which were forming the regeneration blastema. Neuropeptide-treated cells also experienced a dramatic increase in the number of chromatoid bodies. The results obtained in this study suggest that synthesis of RNAs leading to increases in the numbers of nuclear pores and chromatoid bodies is facilitated in neuropeptide-treated cells which are undergoing cell differentiation. The different mechanisms of the effects induced in undifferentiated cells by neuropeptides are discussed.

The presence of intranuclear filamentous inclusions in cerebellar Golgi cells is reported in three patients with cerebellar tumours. Samples of cerebellar cortex were processed for conventional transmission electron microscopy. Cerebellar biopsies were performed according to the basic principles of Helsinki declaration. Intranuclear inclusions observed in oedematous Golgi cells, appeared as straight rodlets up to 3 microm in length and up to 0.4 microm in width, characterized by a periodic or crystalloid structure formed by dense bands, 9.2 nm thick separated by clear spaces, 5.4 nm in width. These structures are considered abnormal protein aggregates apparently induced by excitotoxicity, oxidative stress and impaired energy metabolism.

Pancreatic undifferentiated carcinomas with a neoplastic mesenchymal component (carcinosarcoma) have not been well described to date. The author experienced an autopsy case of a unique pancreatic ductal adenocarcinoma with carcinosarcomatous histology. The patient was a 90 year old Japanese male who died of cahexia with generalized tumor extension. Post-mortem examinations revealed some distinctive or representative components discerned in the tumor tissue. One was the well differentiated ductal adenocarcinoma. The second and the major finding was undifferentiated short spindle shaped or small round sarcomatous cells, which lacked an epithelial nature but showed positivity for CD10+, CD56+, Ki67++, p53++, and were focally positive for Desmin and vimentin. These two components were mixed and constituted the histology of the carcinosarcoma. In another area, anaplastic, large, pleomorphic tumor cells showed the focal immunohistochemical distribution of alpha-feto-protein and human chorionic gonadotropin. An ultrastructural study revealed adenocarcinoma cells with apical mucin secreting granules and well developed ductal differentiation, whereas undifferentiated sarcomatous cells showed primitive fibroblastic or mesenchymal characters without specific differentiation. Conclusively these findings suggested that this well differentiated adenocarcinoma gradually enlarged, accumulated genetic alternations, and then transformed into large and undifferentiated tumor cells, rapidly growing small sarcomatous cells, and a histology of carcinosarcoma.

Comparing Kuffler's recordings of ganglion cell discharges and bipolar cell responses to the same stimuli, deduced on the basis of a knowledge of synaptic connections between the neurons, revealed that the bipolar cell signals had not been modified by synaptic interaction in the inner plexiform layer. This layer therefore receives bipolar cell signals generated by groups of bipolar cells within the center of ganglion cell receptive fields, sorts and distributes the signals to a (compared to the number of photoreceptors and bipolar cells), small number of ganglion cells in such a way that the retinal image can be reconstructed in the visual center by reversing the fusion. Transmission between photoreceptor and bipolar cell is controlled by an information processing circuit receiving information from one photoreceptor, from the large horizontal cell network, formed by synaptic connections between the large horizontal cell processes, from cone networks formed by the cone processes connecting cones and from one small horizontal cell. Interaction between input neurons shapes the input to the bipolar cell. The interaction establishes a gate like control of transmission at the bipolar cell synapse and maintains bipolar cell threshold at a constant level, two features that prevent noise in the output signal. The output is generated by simultaneous input from all input neurons at the bipolar cell synapse, a multiinput synapse. Bipolar cell response is therefore based on perfect timing of fusion of information and of the neural interaction preceding fusion. Proper timing is secured by the dimensions of the components of the circuit measuring in the nanometer range. The volume of the information processing circuit is only 0.3 cubic micrometer, which is less than one two hundredth the volume of the soma of a bipolar cell. Extension of the study of the nervous system to the nanometer level opens a new field of research by making it possible to analyze how information contributed by the sense organs is processed in the nervous system to regulate body functions.

Neurons in the dorsal cochlear nucleus of the guinea pig were classified according to their positivity to the inhibitory neurotransmitter glycine, ultrastructure and projections to the inferior colliculus as indicated by tract-tracing and ultrastructural immunocytochemistry. Only some pyramidal and few giant cells, surrounded by glycinergic boutons containing flat and pleomorphic vesicles, projected to the inferior colliculus as glycine-negative excitatory cells. Smaller neurons in superficial layers of the dorsal cochlear nucleus did not project to the inferior colliculus, and were recognized as glycine-negative granule and unipolar brush cells. Few glycinergic, inhibitory neurons among granule cells were indicated as Golgi-stellate neurons. All small neurons associated to the granule cell areas received few, mainly glycinergic synapses, and their dendrites contacted large boutons (mossy fibers). Other medium-large glycine positive neurons in the superficial (cartwheel) and deep layers (tuberculo-ventral and large-giant) of the dorsal cochlear nucleus did not project to the inferior colliculus. Giant-large glycinergic neurons surrounded by sparse axo-somatic, mostly glycinergic synapses, probably represent commissural neurons projecting to the contralateral cochlear nucleus. Rare boutons, possibly descending from the inferior colliculus, were seen onto pyramidal cells or their dendrites, and these boutons mainly stored glycine positive pleomorphic vesicles or glycine negative round vesicles. No descending mossy fibers storing round vesicles were labelled from the central nucleus of the inferior colliculus. These observations suggest that very few terminals in the dorsal cochlear nucleus of the guinea pig are derived from the inferior colliculus.