Davide Schiffer

Glial fibrillary acidic protein and vimentin in the experimental glial reaction of the rat brain

Glial reaction has been studied in the rat by the immunohistochemical demonstration of glial fibrillary acidic protein (GFAP) and vimentin (VIM) in two experimental conditions. The first was represented by a necrotic cerebral lesion obtained by laser irradiation and the second by the development of experimental tumors induced by transplacental ethylnitrosourea. Reactive astrocytes develop not only in the proximity of the lesion but also distant from it. The intensity of the glial response seems to depend upon the normal distribution of astrocytes and the perilesional edema. GFAP decorates all the reactive astrocytes, whereas VIM is positive only in those at the edges of the lesion. The significance of the different responses in the two models and between the two intermediate filaments is discussed.

A Study of Apoptosis in Normal and Pathologic Nervous Tissue After In situ End-Labeling of DNA Strand Breaks

Abstract. Programmed cell death (PCD) via apoptosis is characterized by nuclear pyknosis and fragmentation, and biochemically by oligonucleosomal cleavage of DNA. Apoptosis occurs in the developing nervous system, whereas its role in neurodegenerative diseases is still debated. Recognition of apoptotic cells has recently been facilitated by in situ end-labeling (ISEL) techniques which identify DNA strand breaks through incorporation of labeled nucleotides. We have applied two ISEL assays to physiological and pathological conditions affecting the nervous system in which PCD is likely to occur. Terminal transferase assay was more sensitive than DNA polymerase assay and allowed the recognition of a larger number of cells than conventional histology. Apoptotic cells were readily found in the developing spinal cord and dorsal root ganglia. Medulloblastomas, gliomas, brain lymphomas and metastases showed abundant apoptotic cells either isolated or grouped in small foci. Labeling was also found in cells without a clearcut apoptotic morphology. Apoptotic cells were not found in Alzheimers disease, amyotrophic lateral sclerosis and human and mouse prionic encephalopathies. Our results show that ISEL is a useful technique for demonstrating apoptotic cells in nervous tissue during development and in brain tumors. Lack of staining in neurodegenerative diseases suggests that other types of PCD might be involved.

Reactive astrogliosis of the spinal cord in amyotrophic lateral sclerosis

Many observations have been carried out on astrogliosis in the cerebral cortex in amyotrophic lateral sclerosis (ALS), whereas little attention has been paid to astrogliosis in the spinal cord. Twenty autopsy cases of sporadic, common form of ALS have been studied. Spinal cords have been examined at the cervical, thoracic and lumbar levels by histological methods and immunohistochemistry for GFAP, Vimentin, Tau-protein, Neurofilaments, PCNA. A gliosis was found in the ventral horns, in dorsal horns and at the transition between gray matter and anterior and lateral funiculi, especially close to laminae VII, VI and V as being due to secondary gliosis. The findings cannot be interpreted on the only basis of the substitutive role of reacting glia. The proposed pathogenetic mechanisms of ALS are evaluated as possible responsible stimuli; the coincidence of the distribution of reactive astrocytes with the entering points of the corticospinal tracts into the gray matter is considered of primary importance. Of special interest are reactive astrocytes at the transition between laminae VII, VI and V and the lateral funiculus, where dystrophic neurites are known to concentrate.

PCV chemotherapy for recurrent oligodendrogliomas and oligoastrocytomas.

OBJECTIVE The role of chemotherapy in the treatment of low-grade oligodendrogliomas and oligoastrocytomas is still unclear. A Phase II study was conducted to determine the benefits and toxicity of the procarbazine, lomustine, and vincristine (PCV) regimen in patients with low-grade oligodendrogliomas and oligoastrocytomas recurrent after surgery alone or surgery with radiotherapy. METHODS Patients with both enhancing and nonenhancing tumors were treated with up to six cycles of standard PCV, and response was evaluated by conventional criteria based on computed tomography or magnetic resonance imaging. RESULTS Sixteen of 26 patients (62%) responded to PCV: 3 (12%) experienced complete response, 13 (50%) experienced partial response, 8 (31%) had stable disease, and 2 (8%) had progressive disease. All symptomatic patients who responded and three with stable disease improved in seizure frequency, lateralizing signs, and symptoms of intracranial hypertension. The response rate for patients with enhancing lesions revealed by computed tomography or magnetic resonance imaging (74%) was significantly higher than that of patients with nonenhancing lesions (29%) (P < 0.05). Both oligodendrogliomas and oligoastrocytomas responded to PCV, with complete responses occurring in association with pure tumors only. The median time to tumor progression of all 26 patients was 24 months and was significantly longer for those with oligodendrogliomas compared with those with oligoastrocytomas (32 versus 12 mo) (P < 0.001). Chemotherapy was well tolerated, with mild hematological toxicity and rare skin rashes being the most frequent sequelae. CONCLUSION These results suggest that chemotherapy with PCV is effective in the treatment of recurrent low-grade oligodendrogliomas and oligoastrocytomas.

c-Jun, JNK/SAPK kinases and transcription factor NF-kappa B are selectively activated in astrocytes, but not motor neurons, in amyotrophic lateral sclerosis.

There is increasing evidence that oxidative damage plays a major role in amyotrophic lateral sclerosis (ALS), but how it contributes to motor neuron degeneration and astrocytic gliosis, two pathologic hallmarks of the disease, is unknown. A few studies have suggested that ALS motor neurons die via apoptosis and show upregulation of c-jun, an immediate early gene that is necessary for neuronal apoptosis. In order to elucidate the mechanisms of cell damage induced by oxidant stress, we have studied in ALS and control spinal cord the immunohistochemical expression of c-Jun, of JNK/SAPK, a kinase that activates c-Jun following various types of stress, and of NF-κB, a transcription factor that is induced by oxidant stress and has prominent neuroprotective functions. An in situ end-labeling assay was performed for detecting apoptotic cells. We show that (a) the JNK/SAPK-c-Jun pathway is dramatically overexpressed in ALS spinal cord; (b) the strongest activation occurs in astrocytes, while motor neurons show unusually low expression of the pathway; (c) increased JNK/SAPK expression in glial cells is accompanied by NF-κB activation, indicating the presence of a protective response to oxidant stress, which is deficient in motor neurons; (d) activation of JNK/SAPK, c-Jun and NF-κB is unrelated to apoptotic cell death. These results support the view that astrocytes are directly involved in the pathologic process of ALS, and might explain the selective vulnerability of motor neurons by their relative lack of antioxidant defenses.

Histologic prognostic factors in ependymoma

The prognostic value of a series of histologic signs and clinical features was studied in a series of 298 ependymomas, collected from different institutions. The distribution of tumor sites varied in relation to patient age, with infratentorial cases prevailing under 4 years. Life table univariate analysis demonstrated as highly significant prognostic factors: (1) the number of mitoses; (2) endothelial hyperplasia; (3) necrosis; (4) intracranial site; (5) age <4 years. Multivariate analysis by tumor site revealed mitoses cell density, age >16 years in supratentorial cases, and subependymoma in infratentorial cases to be prognostically important. Comparison of the anaplastic variant with the other tumor types in intracranial cases did not show a significant difference in survival even though the median survival time of anaplastic cases was shorter. The main conclusion is that the histological criteria employed to diagnose anaplasia in gliomas are not useful for recognizing anaplasia in ependymomas. The number of mitoses is a very important prognostic factor in supratentorial cases, whereas endothelial proliferations and necroses are much less important as prognostic factors than in gliomas.

Safety and factors related to survival after percutaneous endoscopic gastrostomy in ALS

Article abstract Percutaneous endoscopic gastrostomy (PEG) has been proposed as symptomatic treatment of dysphagia in patients with ALS. Safety and factors related to survival after PEG were analyzed in 50 consecutive ALS patients. No major acute or long-term complications were observed. Stabilization or increase in weight were observed after PEG. Median survival after PEG was 185 days, with a worse outcome in patients with weight loss ≥10% healthy body weight and forced vital capacity <65%. PEG may be a useful option in the symptomatic treatment of dysphagia in ALS.

LACK OF APOPTOSIS IN MICE WITH ALS

be detected by this method. However, sublimon-type templates give equally prominent products. Our findings imply that the background of sublimon-derived products generated from control templates makes LX-PCR unreliable as a sole diagnostic method for detecting deleted mtDNAs, except in the case of deletions representing a substantial fraction of mtDNA molecules in a given DNA preparation. We would thus recommend routine serial dilution of all DNA samples to test for the meaningful presence of deleted mtDNA molecules when using LX-PCR, and ideally the verification of all positive findings by Southern blot analysis, before a diagnostic conclusion is reached. Published claims, based exclusively on LX-PCR analysis, that deleted mtDNAs accumulate to high levels in aging and in many disease states , need to be critically re-evaluated in the light of our findings. Acknowledgments We thank M. Niittylahti and O.Lumme for technical assistance, and P. Rustin, I. Holt, S. Khogali and N.-G. Larsson for discussions. This work was supported by grants from the Finnish Academy, Muscular Dystrophy Group, Royal Society, Tampere University Hospital Medical Research Fund, Yrjö Jahnsson Foundation, Finnish Foundation of Alcohol Research and the Pirkanmaa Region Fund of the Finnish Cultural Foundation.

Apoptosis and cell proliferation in human neuroepithelial tumors

Apoptosis and cell proliferation were studied in 180 human neuroepithelial tumors (30 medulloblastomas, 30 intracranial ependymomas, 30 oligodendrogliomas and 90 astrocytic tumors, including 30 astrocytomas, 30 anaplastic astrocytomas and 30 glioblastomas). Apoptotic nuclei were detected by morphology and in situ end-labeling (ISEL) of DNA breaks. The frequency of apoptotic nuclei varied from oncotype to oncotype and their distribution in each oncotype was uneven. An apoptotic index (AI) was calculated; this was high in malignant tumors and in tumors of embryonal origin and lower in tumors of the glial series. The AI/mitotic index (MI) ratio was lower in malignant tumors and higher in benign tumors, suggesting a relationship between apoptosis and cell proliferation. There was no significant correlation of either AI or AI/MI ratio with either labeling index (LI) of Ki-67 clone MIB-1 or with survival. A trends towards low AI/MI ratio in tumors with high LI and short survival was observed. Apoptosis expresses cell loss in tumors, but it did not appear to be a prognostic factor.

Prognostic factors in oligodendroglioma.

BACKGROUND A reliable marker for tumor oligodendroglial cells is not yet available, so that the histological recognition of the tumor still encounters uncertainties. There is no general agreement also on prognostic factors in oligodendroglioma. The inconsistency concerns mainly the histopathological factors. The aim of the study was recognition of prognostic factors in oligodendroglioma. METHODS In a series of ninety-eight oligodendrogliomas, including twenty mixed oligoastrocytomas, clinical [sex, age at surgery, tumor location, symptoms at presentation], therapeutic [extent of resection, year of surgery, post-operative Karnofsky score, post-operative radiotherapy, post-operative chemotherapy], histological [cell density, nuclear pleomorphism, vascular endothelial proliferation, necrosis, microcysts, mitoses, mitotic index (MI), apoptosis, apoptotic index (AI)] and immunohistochemical parameters [MIB-1 and PCNA Labeling Indexes (LIs), staining for GFAP, positivity for p53] were correlated with survival in uni- and multivariate analysis in order to identify their prognostic significance. RESULTS Age at surgery, extent of surgical resection, year of surgery, post-operative Karnofsky score and MIB-1 LI were associated with survival in both uni- and multivariate analysis. Location, symptoms at presentation, mitoses, MI, AI, and PCNA LI showed a significant correlation with survival in uni- but not in multivariate analysis. The twenty cases of oligoastrocytomas did not show any difference in survival from pure oligodendrogliomas. CONCLUSIONS Some clinical and therapeutic factors together with MIB-1 LI play a prognostic role. MIB-1 LI is prognostic with a cutoff of 8%. Histology gives a limited contribution to the prognosis. Oligoastrocytomas had the same outcome and prognostic factors as pure oligodendrogliomas.