Biomedical subjects

T Pezzulo

Publications and source records attributed to T Pezzulo.

8 recordsLinked to original sources

PubMed1995

Synaptic vesicle proteins, synaptophysin and chromogranin A in amyotrophic lateral sclerosis.

In amyotrophic lateral sclerosis (ALS) it is not known which motoneuron is affected first. The study of synaptic proteins may contribute to the clarification of the problem. Fifteen cases of ALS and five control cases were studied with the immunohistochemical demonstration of synaptophysin (Sy) and chromogranin A (CgA). Sy is a typical membrane protein of small synaptic vesicles (SSV), whereas CgA is found in large dense core vesicles (LDCV) and in neurosecretory granules. In controls, Sy is distributed as dots on the neuronal surface, on proximal dendrites and in neuropil, whereas CgA is found in perikarya and dendrites and as puncta in the neuropil. In ALS there is a marked decrease of Sy-positive dots. In chromatolytic neurons and spheroids a diffuse reaction may occur. CgA-positive dots disappear in ALS, sometimes replaced by a dust-like positivity. CgA is produced by Golgi apparatus and its reduction in ALS corresponds to the fragmentation of the Golgi complex, described in the literature. The findings are interpreted as secondary to the lower motoneuron degeneration and discussed in relation to our knowledge on vesicle production and migration in the neuron and on synapses in the anterior horns of spinal cord.

Adult↗

PubMed1994

Ubiquitinated dystrophic neurites suggest corticospinal derangement in patients with amyotrophic lateral sclerosis.

Pathologic changes affecting the upper motoneuron (UMN) were studied in 37 cases of amyotrophic lateral sclerosis (ALS) by histology and immunohistochemistry and by electron and immunoelectron microscopy. The most striking finding was represented by ubiquitin-positive dot-like structures related to (1) glial lipofuscin granules, (2) small polyglucosan bodies and (3) dystrophic neurites. Their distribution areas did not overlap. In ALS cases, ubiquitinated dystrophic neurites were twice as frequent as in controls in the arcuate region of motor cortex; moreover, in ALS cases they were twice as frequent in the spinal cord at the end of corticospinal tracts, compared with the motor cortex. These findings may indicate the presence in ALS of a 'dying-back' of the corticospinal motoneuron, independently of its primary or secondary involvement.

Adult↗

PubMed1994

Proliferating cell nuclear antigen (PCNA) in low-grade astrocytomas: its prognostic significance.

AIMS AND BACKGROUND: A clear line cannot be drawn between well-differentiated and anaplastic astrocytomas, and a subset of low-grade tumors, histologically indistinguishable from the others, behaves similarly to anaplastic astrocytomas. The proliferative index could aid in the identification of this subgroup, for which a different therapeutic approach would be indicated. METHODS: We immunohistochemically evaluated the proliferating cell nuclear antigen (PCNA) expression in 77 well-differentiated astrocytomas, since PCNA has been considered a good proliferation marker. The prognostic significance of PCNA labeling index (LI) was assessed in univariate and multivariate analysis, taking into consideration some clinical and histologic factors known to affect prognosis. RESULTS: PCNA immunostaining identified a subgroup of tumors, characterized by a LI > 5%, with a median survival close to that observed in anaplastic astrocytomas. The survival table of such a group was significantly different from that of the group with a lower LI (p = 0.0009). Multivariate analysis confirmed that PCNA-LI is an independent prognostic factor (p = 0.001). CONCLUSION: These data suggest that PCNA immunostaining can be a useful tool to define the prognosis of low-grade astrocytomas on routine biopsy material.

Adult↗

PubMed1993

Proliferating cell nuclear antigen expression in brain tumors, and its prognostic role in ependymomas: an immunohistochemical study.

Proliferating cell nuclear antigen (PCNA)/cyclin is currently often investigated immunohistochemically in tumors as a marker of cell proliferation, but many problems remain open concerning its reliability as a prognostic factor. PCNA has been studied in a series of 123 brain tumors using the monoclonal antibody PC10. A clear intra- and inter-tumor variability of PCNA-positive nuclei has been found, but taking into account the tumor areas with the highest number of positive nuclei, a positive correlation between this number and the histological malignancy of tumors has been demonstrated. The staining intensity of nuclei was variable; very-intensely positive nuclei, counted separately, are hypothesized to represent nuclei in S-phase of the cell cycle. In ependymomas the investigation included a quantitative statistical analysis. The number of PCNA-positive nuclei correlated with cell density and mitotic index, but only very intensely positive nuclei showed a significant statistical correlation with survival. In spite of the many possibilities of wrong interpretation of PCNA expression, the most important of which is its deregulation, the method is useful in the practice for prognostic purposes. Its important advantages are the possibility of a retrospective application and a visual analysis of the proliferation potential of tumors.

Antigens, Neoplasm↗

PubMed1993

Is polar spongioblastoma a tumor entity?

The distribution of cells in a parallel fashion with palisades of nuclei is common in neuroepithelial tumors. The authors have selected 16 such tumors from their series for study, as examples of different neuroepithelial oncotypes containing palisades of nuclei: three ependymomas, three hemispheric pilocytic astrocytomas, three oligodendrogliomas, three medulloblastomas, three cerebellar astrocytomas, and one central neuroblastoma. In two additional tumors, affecting a 12-year-old girl and a 51-year-old woman, this feature was present in the entire surgical specimen and the diagnosis was consistent with a polar spongioblastoma. This diagnosis applies in the literature to rate tumors of childhood and adolescence, both malignant and with embryonal features. In one specimen, a clear ependymomatous feature was found in a remote area of the tumor and in the other there were ultrastructural characteristics of neuroblastoma. Nuclear palisades can be found as local architectural features in many neuroepithelial tumors. The rare tumors diagnosed as polar spongioblastoma, according to published criteria, correspond to ependymomas and neuroblastomas. Polar spongioblastoma does not exist as a tumor entity.

Astrocytoma↗

PubMed1993

Peripherin immunoreactive structures in amyotrophic lateral sclerosis.

BACKGROUND: Increased levels of the neuron-specific intermediate filament, peripherin, have been recently detected in regenerating motor neurons of rat spinal cord after nerve transection. No data are yet available on peripherin expression in normal and diseased human spinal cord. EXPERIMENTAL DESIGN: We have investigated the presence of peripherin immunoreactive structures in routinely processed spinal cord of human patients with amyotrophic lateral sclerosis and control cases by immunohistochemistry and immunoelectron microscopy. Adjacent sections were stained with antibodies to neurofilaments (NF) and ubiquitin. RESULTS: In control cases, immunoreactivity for peripherin was found in neurons of dorsal root ganglia, in the posterior columns, in dorsal and ventral roots, and in scattered age-related axonal swellings. The cytoplasms of motor neurons were unstained. In amyotrophic lateral sclerosis cases most spheroids were immunoreactive for NF and to a lesser extent for peripherin. A few spheroids were strongly reactive for peripherin and were only weakly stained by antibodies to NF in adjacent sections. Both antibodies to NF and peripherin failed to demonstrate structures corresponding to the intraneuronal filamentous inclusions labeled by ubiquitin. CONCLUSIONS: The accumulation of peripherin and NF in spheroids is likely related to the reduced anterograde transport. Alternatively, the spheroids showing a higher degree of peripherin immunoreactivity might represent regenerating axonal terminals.

Aged↗

PubMed1992

Medullomyoblastoma: report of two cases.

Two cases of medullomyoblastoma in children are described. The muscular component showed different features in the two cases and were associated with neuronal differentiation. Morphological, immunohistochemical, and electron microscopical findings are presented. The origin of the muscular component is discussed in relation to the findings in other cases of the literature. Both differentiation from primitive neuroepithelial cells and derivation from ectomesenchyme are considered.

Biomarkers, Tumor↗

PubMed1992

Age-related ubiquitin deposits in dystrophic neurites: an immunoelectron microscopic study.

Widespread neuritic dystrophy is a hallmark of Alzheimer's disease (AD) and, in a less severe form, of brain ageing in various mammalian species. By immunohistochemistry, diffuse dot-like staining for ubiquitin (Ubq), a polypeptide involved in the degradation of abnormal and short-lived proteins, has been associated with human brain ageing. The nature of the Ubq deposits was investigated by immunogold electron microscopy on autopsy samples from aged human and dog brains. Most of the dot-like staining was localized to the white matter and corresponded to myelinated dystrophic neurites filled by Ubq-labelled lysosomal dense bodies. They did not contain paired helical filaments or multilamellar bodies. A minority of Ubq deposits was represented by amorphous densities in focal enlargements of the myelin sheaths. Our findings show that the spectrum of Ubq changes in ageing brain is wider than formerly recognized, and support the hypothesis that a defective regulation of the lysosomal system might be involved in the pathogenesis of structural abnormalities both in the ageing brain and in Alzheimer's disease.

Aged↗