Glioblastoma Multiforme of the Cerebellum in an Elderly Man. A Case Report

Glioblastoma multiforme of the cerebellum is rare and comprises a small fraction of all glioblastomas. Eighty-five cases have been reported in the literature to date. A 75 year old man is reported with a left cerebellar glioblastoma multiforme. The pathogenesis, course, treatment and prognosis are reviewed.

HLA-Dr Expression by Tumor Cells Compared with Survival in High Grade Astrocytomas

Frozen samples from 78 high grade astrocytomas were reacted with a monoclonal antibody directed against HLA-Dr invariant chain. Survival data was obtained for all 78 cases. HLA-Dr was expressed by a proportion of tumor cells in 65/78 (83 %). Comparison of the survival of positive and negative cases showed that the difference was not statistically significant (p = 0.4). The relevance of the finding is discussed in the context of the immunoreaction to brain tumors.

The Monocyte/Macrophage Infiltrate in 35 Medulloblastomas: A Paraffin-Wax Study

We have studied formalin fixed, paraffin-wax embedded tissue from 35 medulloblastomas, collected over 23 years (27 non-desmoplastic and 8 desmoplastic) with KP1 and Mac387 two monoclonal anti-monocytes/macrophage (M/Ms) antibodies recommended for use on paraffin wax embedded tissue. In non-desmoplastic medulloblastomas, outside areas of necrosis, M/Ms were detected in 50% of cases with KP1 and 52% with Mac387. M/Ms were seen In 100% of desmoplastic medulloblastomas with both antibodies. Semiquantitative assessment revealed that, on average, desmoplastic tumors had at least three times as many Infiltrating M/Ms as non-desmoplastic tumors. There was no significant difference in the findings with the two antibodies or, between recently embedded and « older » tumors. The findings may be indicative of the presence of a host M/Ms immune response in medulloblastoma, which may be more accentuated in desmoplastic medulloblastomas. Furthermore, we conclude that these antibodies are quite suitable for the study of infiltrating M/Ms, thus lessening (but not obviating) the need for frozen tissue for immunohistological studies.

Mononuclear Cell Infiltrate and Hla-Dr Expression in 28 Pituitary Adenomas

Frozen sections from 28 pituitary adenomas were reacted with a panel of monoclonal antibodies to macrophages, lymphocytes and HLA-Dr invariant chain. A low number of macrophages were demonstrated in all tumors, mainly perivascular. CD8 and CD4 lymphocytes were detected in even smaller numbers in 80% and 14% of tumors respectively. B lymphocytes were present in only 1 case. An occasional NK cell was present in 1/13 cases studied. HLA-Dr antigen was expressed by macrophages in all cases and by tumor cells in 2 growth hormone-producing adenomas/19 adenomas. These findings may represent evidence for a low degree of cellular immune response to pituitary adenomas.

Pituitary Metastasis from Malignant Bronchial Carcinoid

Metastases from a carcinoid tumor to the pituitary gland have, to our knowledge, not been described. We present a 49-year-old woman diagnosed as having a primary carcinoid tumor arising in the submucosa of a large bronchus who 8 years later presented with multiple metastases including one to the pituitary gland, which was in partial failure of pituitary function. This case illustrates than when confronted with a pituitary tumor resembling an adenoma but negative for pituitary hormones, the possibility of a metastasis from a carcinoid tumor should be considered.

Evaluation of surface water quality using an ecotoxicological approach: a case study of the Piracicaba River (São Paulo, Brazil)

A long-term study was conducted to evaluate Piracicaba River water (São Paulo state, Brazil) using different methodologies and organisms. During 1 year (February 2011 to January 2012), water samples were collected monthly at six different locations and exposed under laboratory conditions to the microcrustaceans Ceriodaphnia dubia and Ceriodaphnia silvestrii for 7 days and to the fish Danio rerio for 4 days to evaluate effects on reproduction and on gill morphology, respectively. Physical-chemical parameters of the water were also measured. Physical-chemical characteristics demonstrated decreasing water quality from upstream to downstream of the river. Effects on the reproduction of C. dubia and C. silvestrii were observed in 3 months (February and March 2011 and January 2012) and occurred in samples collected close to industrialized cities like Americana and Piracicaba. Evaluation of the gills showed normal function of the organ during all months, except in February, September, and October for some locations.

Anatomical patterns of patent foramen ovale (PFO): do they matter for percutaneous closure?

AIM

The aim of this study was to describe and classify the various anatomical pattern of patent foramen ovale (PFO) with transesophageal echocardiography (TEE) and to relate such classification to the selection of PFO closure devices.

METHODS

This study enrolled 216 PFO patients (118 females) mostly with previous cryptogenic stroke or transitory ischemic attack (TIA) who underwent percutaneous closure of PFO with deep sedation under TEE control. Anatomical patterns were classified as follows: simple: PFO characterised by central/superior eccentric shunt or with a valve mechanism (45%); reduse: widely redundant septum primum (22%); ASA: atrial septal aneurysm (11%); EASA: entire atrial septal aneurysm (1.4%); CRIB: cribriform septum primum (9%); tunnel: tunnel between septum primum and secundum >10 mm (11%). Degree of right-to-left shunt, either at basal condition or at Valsalva manoeuvre, was classified as: 1=mild (45%); 2=moderate (42%); 3=severe (13%). Additional right-atrium anatomical features are also described.

RESULTS

Procedure was successful in 100% of the cases. At follow-up recurrent TIA occurred in two patients. Residual shunts were present in 4.9% of the patients after Valsalva manoeuvre. Palpitations were reported in 4%.

CONCLUSIONS

Closing the PFO choosing the device following strict anatomical criteria based on TEE assessment allowed excellent immediate and late results minimizing residual shunts.

The nicotinic activation of the denervated sympathetic neuron of the rat

Nicotinic responses to endogenous acetylcholine and to exogenously applied agonists have been studied in the intact or denervated rat sympathetic neuron in vitro, by using the two-microelectrode voltage-clamp technique. Preganglionic denervation resulted in progressive decrease of the synaptic current (excitatory postsynaptic current, EPSC) amplitude, which disappeared within 24 h. These effects were accompanied by changes in ion selectivity of the nicotinic channel (nAChR). The extrapolated EPSC null potential (equilibrium potential for acetylcholine action, E(Syn)) shifted from a mean value of -15.9+/-0.7 mV, in control, to -7.4+/-1.6 mV, in denervated neurons, indicating a decrease of the permeability ratio for the main components of the synaptic current (P(K)/P(Na)) from 1.56 to 1.07. The overall properties of AChRs were investigated by applying dimethylphenylpiperazinium or cytisine and by examining the effects of endogenous ACh, diffusing within the ganglion after preganglionic tetanization in the presence of neostigmine. The null potentials of these macrocurrents (equilibrium potential for dimethylphenylpiperazinium action, E(DMPP); and equilibrium potential for diffusing acetylcholine, E(ACh), respectively) were evaluated by applying voltage ramps and from current-voltage plots. In normal neurons, E(Syn) (-15.9+/-0.7 mV) was significantly different from E(DMPP) (-26.1+/-1.0) and E(ACh) (-31.1+/-3.3); following denervation, nerve-evoked currents displayed marked shifts in their null potentials (E(Syn)=-7.4+/-1.6 mV), whereas the amplitude and null potential of the agonist-evoked macrocurrents were unaffected by denervation and its duration (E(DMPP)=-26.6+/-1.2 mV). It is suggested that two populations of nicotinic receptors, synaptic and extrasynaptic, are present on the neuron surface, and that only the synaptic type displays sensitivity to denervation.

DES implantation in saphenous vein and left internal mammary grafts

Forty percent of patients treated with CABG need further revascularizations after 10 years mainly due to saphenous--more than arterial--graft disease. In this issue, the Authors make a critical review of current available literature on the treatment of saphenous and arterial graft disease, a subset of lesions for which a clear consensus for DES use is still lacking. The Authors examine both the positive and negative aspects of DES use in this setting. Percutaneous revascularizations with DES are feasible and safe. The antiproliferative properties of DES seem to be effective even in the treatment of bypass disease, in particular in saphenous grafts. The clinical efficacy of a treatment with DES is expressed mainly in the reduction of in-stent restenosis and, therefore, in the rates of target lesion revascularization (TLR). Moreover, the use of DES is not associated to higher rates of stent thrombosis and, in case of reintervention, recurrence rates seem to be limited. However, the benefit provided by DES in prevention of restenosis may be limited by the progression of the disease in other segments than those treated with stents. Percutaneous treatment of arterial bypass with DES is feasible and safe. Most of available data on DES are on anastomotic disease (data on bypass ostium and shaft are too scarce to draw any conclusion). In this case, where the use of stents is imperative, there is no evidence of advantages gained by the use of DES over BMS in terms of new revascularizations. Some unanswered questions on DES use in this setting still remain. For this reason new randomized trials are required to definitively give a reliable answer on DES efficacy in this subset of lesions.

Endovascular intervention in the treatment of congenital heart disease in adults

Over the last years, endovascular intervention have become an important part of treatment in patients with congenital heart disease particularly for residual defects after surgery done in infancy. These transcatheter procedures can be described as dilatation of stenotic sites (angioplasty, endovascular stenting and valvuloplasty) or as a closure of anomalous openings (device closure defects and vascular embolisation). Balloon valvuloplasty, without or with stent, is the procedure of choice in adults with pulmonary valve stenosis, pulmonary arteries stenosis, bicuspid aortic valve stenosis without calcification, aortic re-coarctation. Treatment of native aortic coarctation is still under debate. Devices for closing atrial and ventricular septal defects or patent ductus arteriosus have been developed and are now widely used. Transcatheter, plug or coil occlusion is nowadays the goal treatment in a wide range of arterial and venous vascular connections. This review describes the current role of each major catheter-directed therapy in the treatment of congenital heart disease in adults.

Drug-eluting stents: towards new endpoints

Drug-eluting stents (DES) have significantly reduced the rates of in-stent restenosis (ISR). As previously observed with bare-metal stents (BMS), either patient's clinical characteristics and lesion morphology may influence the risk of recurrence even with DES. In this review we will focus on the most recent available data on clinical settings where DES efficacy on long-term outcomes are largely unknown. In particular, we report on very complex lesions (bifurcations, small vessels, chronic total occlusions, in-stent restenosis) myocardial infarction, multivessel disease, treatment of bypass graft and of unprotected left main disease. Several issues are still open on DES routinary use for these indications, mainly as far as stent thrombosis is concerned. Recent pathological studies show that DES are characterized by chronic inflammatory infiltrates and delayed endothelialization. Therefore, this effect could translate in a ''vulnerable period'' for thromboses longer than with BMS. Even though large meta-analysis have excluded higher rates of stent thrombosis with DES rather than with BMS, few cases of unusual very late stent thrombosis have been described, pointing out that this problem seems to be still unsolved. Although DES provide better angiographic outcomes in each clinical setting, further randomized studies are running to assess their safety and efficacy on currently off-label indications.

Clinical utility of IVUS in 2005

Intravascular ultrasounds (IVUS) allowed an innovative visualization of coronary artery disease. This technique developed first in the research field and, then, it was introduced in clinical practice as a supplement to coronary angiography in diagnosis of the severity of ischemic heart disease. The characteristic tomographic view of coronary plaque supplied by IVUS allowed to overcome the limitations of coronary angiography and to add important supplemental information in understanding the mechanism of action of several interventional devices. In this review we analyze current indications of use of IVUS in clinical practice and the future applications of IVUS-related techniques for the diagnosis of coronary artery disease.

Phenotype commitment in vascular smooth muscle cells derived from coronary atherosclerotic plaques: differential gene expression of endothelial nitric oxide synthase

Unstable angina and myocardial infarction are the clinical manifestations of the abrupt thrombotic occlusion of an epicardial coronary artery as a result of spontaneous atherosclerotic plaque rupture or fissuring, and the exposure of highly thrombogenic material to blood. It has been demonstrated that the proliferation of vascular smooth muscle cells (VSMCs) and impaired bioavailabilty of nitric oxide (NO) are among the most important mechanisms involved in the progression of atherosclerosis. It has also been suggested that a NO imbalance in coronary arteries may be involved in myocardial ischemia as a result of vasomotor dysfunction triggering plaque rupture and the thrombotic response. We used 5' nuclease assays (TaqMan PCRs) to study gene expression in coronary plaques collected by means of therapeutic directional coronary atherectomy from 15 patients with stable angina (SA) and 15 with acute coronary syndromes (ACS) without ST elevation. Total RNA was extracted from the 30 plaques and the cDNA was amplified in order to determine endothelial nitric oxide synthase (eNOS) gene expression. Analysis of the results showed that the expression of eNOS was significantly higher (p<0.001) in the plaques from the ACS patients. Furthermore, isolated VSMCs from ACS and SA plaques confirmed the above pattern even after 25 plating passages. In situ RT-PCR was also carried out to co-localize the eNOS messengers and the VSMC phenotype. The eNOS gene was more expressed in ACS plaques and VSMCs cultured from them, thus indicating that: a) the expression of the most important differentiation markers is retained under in vitro conditions; and b) NO may play a pivotal role in coronary artery disease. Our findings suggest a new cell system model for studying the pathophysiology of unstable angina and myocardial infarction.

Inhibitors of platelets glycoprotein IIb/IIIa (GP IIb/IIIa) receptor: rationale for their use in clinical cardiology

The glycoprotein IIb/IIIa (GP IIb/IIIa) receptor is the most important receptor involved in platelet aggregation. A stable GP IIb/IIIa inhibition is required when a massive platelet activation triggers thrombosis. Three GP IIb/IIIa inhibitors are currently approved for clinical use: abciximab, tirofiban and integrilin. Their different pharmacodynamic and pharmacokinetic properties reflect a different efficacy in platelet inhibition.

Biophysical properties of the silent and activated rat sympathetic neuron following denervation

A biophysical description of the denervated rat sympathetic neuron is reported, obtained by the two-electrode voltage-clamp technique in mature intact superior cervical ganglia in vitro. At membrane potential values negative to -50 mV, the normal, quiescent neuron displays voltage-dependent K and Cl conductances; following direct or synaptic stimulation (15Hz for 10 s), the neuron moves to a new resting state characterized by increased amplitude and voltage dependence of Cl conductance. Denervation produces two main effects: 1) resting Cl conductance gradually increases while its voltage-dependence decreases; by 30 days a high-conductance resting state prevails, almost independent of membrane potential in the -50/-110 mV range; 2) the increase in amplitude and voltage-dependence of Cl conductance, produced by direct stimulation in control neurons, is less marked in denervated neurons, and is observed over an increasingly small range of membrane potentials. Thirty days after denervation, the prevailing high-conductance resting state appears virtually insensitive to changes in membrane potential and stimulation. Voltage-dependent potassium currents involved in spike electrogenesis (the delayed compound potassium current and the fast transient potassium current) exhibit an early drastic decrease in peak amplitude in the denervated neuron; the effect is largely reversed after 6 days. Remarkable changes in fast transient potassium current kinetics occur following denervation: the steady-state inactivation curve shifts by up to +15 mV toward positive potential and voltage sensitivity of inactivation removal becomes more steep. A comprehensive mathematical model of the denervated neuron is presented that fits the neuron behavior under current-clamp conditions. It confirms that neuronal excitability is tuned by the conductances (mostly chloride conductance) that control the resting membrane potential level, and by fast transient potassium current. Impairment of the latter reduces both inward threshold charge for firing and spike repolarization rate, and fast transient potassium current failure cancels the voltage dependence of both processes.

First Report of Clubroot of Eruca sativa Caused by Plasmodiophora brassicae in Brazil

Eruca sativa Mill. (family Brassicaceae), with its origin in western Asia, is a culinary and pharmacological species cultivated in Europe, Brazil, and other countries. In the United States, it is a minor crop known as arugula or roquette. Clubroot on E. sativa has not been reported in Brazil and has been reported once in the United States in 1914 (1,2,3). On several occasions since 2000, stunted and wilted plants (cv. Rúcula Cultivada) were collected from growers' fields and greenhouses that had been direct-seeded in Vargem Bonita, DF (two fields and one greenhouse) and Quatro Barras, PR (two fields). The infected arugula crops were found in areas where other plants from the genus Brassica were traditionally cultivated. Disease incidence in individual fields varied from 20 to 80%. Diseased plants were severely affected with hypertrophic, malformed roots, and root galls resembling Woronin's description (4). Plasmodia and resting spores in thin sections prepared from root galls were observed with compound and electron microscopes. Pathogenicity tests were conducted on arugula and Brassica pekinensis (Lour.) Rupr. (universal host) with inoculum from naturally infected arugula. The soil of potted test plants at the four-to-five-leaf stage was drenched with a suspension of resting spores. Symptoms identical to those observed on the original plants were produced on all inoculated plants 2 to 3 weeks after inoculation. Control plants remained symptomless. The pathogen was positively identified as Plasmodiophora brassicae Wor. with the combination of macroscopic and microscopic symptoms and signs of the disease and pathogen. P. brassicae was first reported in Brazil in 1965 in the state of São Paulo and in the 1980s in Distrito Federal on several members of the Brassicae. To our knowledge, this is the first report of P. brassicae infecting E. sativa in Brazil. Arugula is a susceptible host and should not be planted on P. brassicae-infested land. References: (1) D. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN. 1989. (2) D. F. Farr et al. Fungal Databases. Systematic Botany and Mycology Laboratory, On-line publication. ARS, USDA, 2003. (3) J. S. Karling. The Plasmodiophorales. Published by J. S. karling, NY. 1942. (4) M. S. Woronin. Plasmodiophora brassicae the Cause of Cabbage Hernia. Phytopathological Classics 4. The American Phytopathological Society, Ithaca, NY, 1934.

No evidence for calcium electrogenic exchanger in frog semicircular canal hair cells

We investigated the possibility that, in hair cells mechanically isolated from frog semicircular canals, Ca2+ extrusion occurs via a Na+ : Ca2+ (cardiac type) or a Na+ : Ca2+,K+ (retinal type) exchanger. Cells concurrently imaged during whole-cell patch-clamp recordings using the Ca2+ sensitive fluorescent dye Oregon Green 488 BAPTA-1 (100 micro m) showed no voltage dependence of Ca2+ clearance dynamics following a Ca2+ load through voltage-gated Ca2+ channels. Reverse exchange was probed in hair cells dialyzed with a Ca2+- and K+-free solution, containing a Na+ concentration that saturates the exchanger, after zeroing the contribution to the whole-cell current from Ca2+ and K+ conductances. In these conditions, no reverse exchange current was detected upon switching from a Ca2+-free external solution to a solution containing concentrations of Ca2+ alone, or Ca2+ + K+ that saturated the exchanger. By contrast, the same experimental protocol elicited peak exchange currents exceeding 100 pA in gecko rod photoreceptors, used as positive controls. In both cell types, we also probed the forward mode of the exchanger by rapidly increasing the intracellular Ca2+ concentration using flash photolysis of two novel caged Ca2+ complexes, calcium 2,2'-([1-(2-nitrophenyl)ethane-1,2-diyl]bis(oxy))bis(acetate) and calcium 2,2'-([1-(4,5-dimethoxy-2-nitrophenyl)ethane-1,2-diyl]bis(oxy)) bis(acetate), in the presence of internal K+ and external Na+. No currents were evoked by UV-triggered Ca2+ jumps in hair cells, whereas exchanger conformational currents up to 400 pA, followed by saturating forward exchange currents up to 40 pA, were recorded in rod photoreceptors subjected to the same experimental conditions. We conclude that no functional electrogenic exchanger is present in this hair cell population, which leaves the abundant plasma membrane Ca2+-ATPases as the primary contributors to Ca2+ extrusion.

Quantitative neuropathological analysis of sudden infant death syndrome

Detailed stereological analyses of specific regions of brains of children who had died from Sudden Infant Death Syndrome (SIDS) was undertaken to determine whether global evidence of an underlying pathology exists, contributing to an increased susceptibility to SIDS. A significant reduction in the total number of neocortical neurones and neurone volume was observed in SIDS normal birth weight (NBW) infants in comparison to controls. A significant reduction in both volume and total neurone number were also noted in the dorsal motor nucleus of the vagus in SIDS NBW group when compared with controls. Anomalies in regions of the brain involved with cardiorespiratory control (brainstem) and arousal (brainstem and neocortex) may play a crucial role in the chain of events resulting in a SIDS event.

Infantile cerebellar thrombosis: a case of lupus anticoagulants?

Lupus Anticoagulants (LA) pathology is a disease frequently associated with venous and/or arterial thrombosis. The authors describe a 6 year-old boy complaining cephalea and emesis, followed by lethargy, in whom antiphospholipids antibodies were detected. Brain magnetic resonance scans showed lesions of the cerebellum. The characteristics of LA disease are discussed.

Percutaneous coronary revascularisation in women

Numerous studies of sex differences in morbidity and mortality after an episode of acute coronary disease shown unclear results. In particular is not clear if women undergoing coronary revascularization procedures have adverse in-hospital and long-term outcomes compared with men. Recent clinical trial have provided new insights into this problem. The influence on gender differences for the decision to undertake coronary angiography and percutaneous transluminal coronary angioplasty will be discussed.

Dynamics of intracellular calcium in hair cells isolated from the semicircular canal of the frog

Changes in cytosolic free Ca(2+) concentration ([Ca(2+)]i) were monitored optically in hair cells mechanically isolated from frog semicircular canals using the membrane-impermeant form of the Ca(2+)-selective dye Oregon Green 488 BAPTA-1 (OG, 100 microM). Cells stimulated by depolarization under whole-cell voltage clamp conditions revealed Ca(2+) entry at selected sites (hotspots) located mostly in the lower (synaptic) half of the cell body. [Ca(2+)]i at individual hotspots rose with a time constant tau1 approximately 70 ms and decayed with a bi-exponential time-course (tau2 approximately 160, tau3 approximately 2500 ms) following a 160 ms depolarization to -20 mV. With repeated stimulation [Ca(2+)]i underwent independent amplitude changes at distinct hotspots, suggesting that the underlying Ca(2+) channel clusters can be regulated differentially by intracellular signalling pathways. Block by nifedipine indicated that the L-type Ca(2+)channels are distributed at different densities in distinct hotspots. No diffusion barrier other than the nuclear region was found in the cytosol, so that, during a prolonged depolarization (lasting up to 1s), Ca(2+) was able to reach the cell apical ciliated pole. The effective Ca(2+) diffusion constant, measured from the progression of Ca(2+) wavefronts in the cytosol, was approximately 57 microm(2)/s. Our results indicate that in these hair cells, buffered diffusion of Ca(2+) proceeds evenly from the source point to the cell interior and is dominated by the diffusion constant of the endogenous mobile buffers.

Laboratory markers of hypercoagulability

Investigations carried out over the last 40 years have demonstrated that coronary artery thrombosis is the critical event underlying myocardial infarction and unstable angina. The existence of a prolonged hypercoagulable state preceding the thrombotic event has been postulated for some time and significant associations have been established between the plasma concentrations of a number of hemostatic variables and the frequency of myocardial infarction. High plasma fibrinogen, factor VII/VIIa, tissue-type plasminogen activator and plasminogen activator inhibitor levels have been associated with at least as great a risk of developing myocardial (re)infarction or sudden death as high cholesterol levels, especially in the young. In the last year more sensitive assays have been developed, and they should allow a precise biochemical definition of hypercoagulable states. The significance of these new assays and their role in defining a hypercoagulable state in different conditions are analyzed.

Hemostatic markers and prognosis in ischemic heart disease

Failure of traditional risk factors in identifying patients who develop a cardiac event, has led investigators to focus on other factors involved in precipitating cardiac events. As acute or subacute thrombosis is the major complication of atherosclerotic plaque rupture, attention has been dedicated to prothrombotic markers as possible risk factors. Recently, the role of new laboratory markers in predicting the risk of cardiac events has been evaluated in large epidemiological studies. The results of these studies as well as the value and applicability of new prothrombotic markers in the clinical practice are discussed.

Prothrombotic genetic markers

The last decade has been characterized by an explosion of research studies on genetic epidemiology. In particular, as far as ischemic heart disease is concerned, a lot of research was focused on prothrombotic genetic risk factors. Unfortunately, the success of this approach in the field of venous thrombosis has not been replicated in the field of myocardial infarction. In the present editorial, a comment on the studies already available is provided and the possible limitations of the present approach are analyzed.

Characterisation of molecular alterations in microdissected archival gliomas

Classification of gliomas according to their molecular characteristics may be important in future histopathological diagnosis. However, gliomas frequently display heterogeneity at the histological, biological and molecular level. In this study of archival diagnostic gliomas, precision microdissection was used to enrich samples in the most malignant cells or to investigate intratumoural histological heterogeneity. Analysis of tumour samples microdissected from the most aggressive regions, representative of the histopathological diagnosis, revealed PTEN mutations in 4/14 anaplastic astrocytomas, 4/13 glioblastomas and 1 gliosarcoma, but not in 19 low-grade gliomas. Using a novel PCR procedure and direct sequence analysis of the entire coding sequence, TP53 mutations were detected in 1/3 pilocytic astrocytomas, 3/13 astrocytomas, 4/14 anaplastic astrocytomas, 5/13 glioblastomas and 1 gliosarcoma. All but one of the tumours with TP53 mutation showed p53 immunopositivity, but 5 low-grade and 10 high-grade gliomas had p53 protein nuclear accumulation in the absence of detectable mutation. p53 status was unrelated to p21 expression. Neither PTEN nor TP53 mutations influenced the proliferative index or microvessel density of high-grade astrocytomas. Unusual findings include: TP53 mutation in a juvenile pilocytic astrocytoma; TP53 and PTEN mutations in a de novo glioblastoma, a gliosarcoma with identical mutations in gliomatous and sarcomatous components, and an infratentorial anaplastic astrocytoma with an earlier supratentorial grade II astrocytoma bearing the same TP53 mutation but not the PTEN mutation or loss of heterozygosity (LOH) of 10q23. Similarly, the transition to high-grade histology was associated with acquisition of PTEN mutations and 10q23.3 LOH in two de novo high-grade tumours with regions of low-grade histology.

Regional distribution of calcium currents in frog semicircular canal hair cells

In the present work we studied the regional expression of voltage-dependent Ca channels in hair cells from the frog semicircular canals, employing whole-cell patch-clamp on isolated and in situ hair cells. Although Ca channels are thought to play a major role in afferent transmission, up to now no data were available regarding their distribution in vestibular organs. The problem appears of interest, especially in the light of recent results showing the presence of multiple Ca current components in semicircular canal hair cells. Our data suggest the presence, in all regions of the crista ampullaris, of two classes of cells, one displaying an inactivating Ca current (R1) and one lacking it. In the former cells, Ca current amplitude decreased from the central to the peripheral zone (the maximal currents being observed in the intermediate zone). Only L-type and R2 current components displayed regional differences in expression, whereas the size and properties of R1, although variable among cells, were not regionalized. However, in cells lacking R1, Ca current amplitudes were similar regardless of cell shape and location. The possible contributions of this Ca current distribution to afferent discharge properties are discussed.

Ca2+-dependent kinetics of hair cell Ca2+ currents resolved with the use of cesium BAPTA

Hair cells in the frog semicircular canal, studied by the whole-cell patch-clamp technique, display three distinct Ca2+ currents: two non-inactivating components (L type and R type, the latter termed R2 in the following) and a second R type current (termed R1), which runs down first and inactivates in a Ca2+-dependent fashion. Since intracellular EGTA, up to 5 mM, did not display major effects on such inactivation, we used increasing amounts of BAPTA in the patch pipette, to control [Ca2+]i more efficiently and investigate whether modifications in [Ca2+]i at the cytoplasmic side of the channel affect the inactivation of the RI component and in general the gating of all channel types. The results here reported show that (1) K+ currents heavily contaminate recordings obtained using high concentrations of BAPTA in its commercially available K+ salt form; (2) BAPTA Cs+ salt can be satisfactorily employed to obtain reliable recordings; (3) the kinetics of channel gating and R1-channel inactivation are indeed markedly affected by effectively buffering [Ca2+]i.

Synaptic stimulation of nicotinic receptors in rat sympathetic ganglia is followed by slow activation of postsynaptic potassium or chloride conductances

Two slow currents have been described in rat sympathetic neurons during and after tetanization of the whole preganglionic input. Both effects are mediated by nicotinic receptors activated by native acetylcholine (ACh). A first current, indicated as IAHPsyn, is calcium dependent and voltage independent, and is consistent with an IAHP-type potassium current sustained by calcium ions accompanying the nicotinic synaptic current. The conductance activated by a standard synaptic train was approximately 3.6 nS per neuron; it was detected in isolation in 14 out of a 52-neuron sample. A novel current, IADPsyn, was described in 42/52 of the sample as a post-tetanic inward current, which increased in amplitude with increasing membrane potential negativity and exhibited a null-point close to the holding potential and the cell momentary chloride equilibrium potential. IADPsyn developed during synaptic stimulation and decayed thereafter according to a single exponential (mean tau = 148.5 ms) in 18 neurons or according to a two-exponential time course (tau = 51.8 and 364.9 ms, respectively) in 19 different neurons. The mean peak conductance activated was approximately 20 nS per neuron. IADPsyn was calcium independent, it was affected by internal and external chloride concentration, but was insensitive to specific blockers (anthracene-9-carboxylic acid, 9AC) of the chloride channels open in the resting neuron. It is suggested that gADPsyn represents a specific chloride conductance activatable by intense nicotinic stimulation; in some neurons it is even associated with single excitatory postsynaptic potentials (EPSCs). Both IAHP and IADPsyn are apparently devoted to reduce neuronal excitability during and after intense synaptic stimulation.

Nicotinic EPSCs in intact rat ganglia feature depression except if evoked during intermittent postsynaptic depolarization

The involvement of the postsynaptic membrane potential level in controlling synaptic strength at the ganglionic synapse was studied by recording nicotinic fast synaptic currents (EPSCs) from neurons in the intact, mature rat superior cervical ganglion, using the two-electrode voltage-clamp technique. EPSCs were evoked by 0.05-Hz supramaximal stimulation of the preganglionic sympathetic trunk over long periods; their peak amplitude (or synaptic charge transfer) over time appeared to depend on the potential level of the neuronal membrane where the nicotinic receptors are embedded. EPSC amplitude remained constant (n = 6) only if ACh was released within repeated depolarizing steps of the postganglionic neuron, which constantly varied between -50 and -20 mV in consecutive 10-mV steps, whereas it decreased progressively by 45% (n = 9) within 14 min when the sympathetic neuron was held at constant membrane potential. Synaptic channel activation, channel ionic permeation and depolarization of the membrane in which the nicotinic receptor is localized must occur simultaneously to maintain constant synaptic strength at the ganglionic synapse during low-rate stimulation (0.03-1 Hz). Different posttetanic (20 Hz for 10 s) behaviors were observed depending on the mode of previous stimulation. In the neuron maintained at constant holding potential during low-rate stimulation, the depressed EPSC showed posttetanic potentiation, recovering approximately 23% of the mean pretetanic values (n = 10). The maximum effect was immediate in 40% of the neurons tested and developed over a 3- to 6-min period in the others; thereafter potentiation vanished within 40 min of 0.05-Hz stimulation. In contrast, no statistically significant synaptic potentiation was observed when EPSC amplitudes were kept constant by repeated -50/-20-mV command cycles (n = 12). It is suggested that, under these conditions, posttetanic potentiation could represent an attempt at recovering the synaptic strength lost during inappropriate functioning of the ganglionic synapse.

Calcium currents in hair cells isolated from semicircular canals of the frog

L-type and R-type Ca(2+) currents were detected in frog semicircular canal hair cells. The former was noninactivating and nifedipine-sensitive (5 microM); the latter, partially inactivated, was resistant to omega-conotoxin GVIA (5 microM), omega-conotoxin MVIIC (5 microM), and omega-agatoxin IVA (0.4 microM), but was sensitive to mibefradil (10 microM). Both currents were sensitive to Ni(2+) and Cd(2+) (>10 microM). In some cells the L-type current amplitude increased almost twofold upon repetitive stimulation, whereas the R-type current remained unaffected. Eventually, run-down occurred for both currents, but was prevented by the protease inhibitor calpastatin. The R-type current peak component ran down first, without changing its plateau, suggesting that two channel types generate the R-type current. This peak component appeared at -40 mV, reached a maximal value at -30 mV, and became undetectable for voltages > or =0 mV, suggestive of a novel transient current: its inactivation was indeed reversibly removed when Ba(2+) was the charge carrier. The L-type current and the R-type current plateau were appreciable at -60 mV and peaked at -20 mV: the former current did not reverse for voltages up to +60 mV, the latter reversed between +30 and +60 mV due to an outward Cs(+) current flowing through the same Ca(2+) channel. The physiological role of these currents on hair cell function is discussed.

Neurohypophyseal pilocytic astrocytoma invading the skull base

We describe the clinical presentation, neuroradiological and histological findings of an unusual case of pilocytic astrocytoma of the neurohypophysis, and discuss the related surgical and prognostic issues of this neoplasm which invaded the skull base and the sphenoid sinus. Only four histologically proven cases of such a tumour have been reported in the English literature, and the pathological features and behaviour of this neoplasm still await definition.

Neutrophil infiltration into human gliomas

Human gliomas were analysed for the infiltration of neutrophils using immunohistochemistry by staining sections for CD15-positive and myeloperoxidase-positive cells. Over 70% of all glioma samples analysed (n = 105) had significant neutrophil infiltration, but there was a marked and significant correlation between tumour grade and the extent of the neutrophil infiltration. In the low grade tumours only 40-50% had significant infiltration, while in glioblastoma multiforme over 85% of the samples analysed had significant infiltration. Numbers of neutrophils infiltrating glioblastoma multiforme tumours were also greater than in the other tumour groups. Circulating white blood cell counts were elevated above the normal range in all glioma patients, but this elevation was entirely due to increased numbers of circulating neutrophils. Again, the highest numbers of circulating neutrophils were seen in the glioblastoma multiforme patients. These experiments indicate that glioma-derived factors may directly or indirectly affect the number of circulating neutrophils and influence their infiltration into the tumours.

Participation of a chloride conductance in the subthreshold behavior of the rat sympathetic neuron

The presence of a novel voltage-dependent chloride current, active in the subthreshold range of membrane potential, was detected in the mature and intact rat sympathetic neuron in vitro by using the two-microelectrode voltage-clamp technique. Hyperpolarizing voltage steps applied to a neuron held at -40/-50 mV elicited inward currents, whose initial magnitude displayed a linear instantaneous current-voltage (I-V) relationship; afterward, the currents decayed exponentially with a single voltage-dependent time constant (63.5 s at -40 mV; 10.8 s at -130 mV). The cell input conductance decreased during the command step with the same time course as the current. On returning to the holding potential, the ensuing outward currents were accompanied by a slow increase in input conductance toward the initial values; the inward charge movement during the transient ON response (a mean of 76 nC in 8 neurons stepped from -50 to -90 mV) was completely balanced by outward charge displacement during the OFF response. The chloride movements accompanying voltage modifications were studied by estimating the chloride equilibrium potential (E(Cl)) at different holding potentials from the reversal of GABA evoked currents. [Cl(-)](i) was strongly affected by membrane potential, and at steady state it was systematically higher than expected from passive ion distribution. The transient current was blocked by substitution of isethionate for chloride and by Cl(-) channel blockers (9AC and DIDS). It proved insensitive to K(+) channel blockers, external Cd(2+), intracellular Ca(2+) chelators [bis-(o-aminophenoxy)-N,N,N',N'-tetraacetic acid (BAPTA)] and reduction of [Na(+)](e). It is concluded that membrane potential shifts elicit a chloride current that reflects readjustment of [Cl(-)](i). The cell input conductance was measured over the -40/-120-mV voltage range, in control medium, and under conditions in which either the chloride or the potassium current was blocked. A mix of chloride, potassium, and leakage conductances was detected at all potentials. The leakage component was voltage independent and constant at approximately 14 nS. Conversely, gCl decreased with hyperpolarization (80 nS at -40 mV, undetectable below -110 mV), whereas gK displayed a maximum at -80 mV (55.3 nS). Thus the ratio gCl/gK continuously varied with membrane polarization (2.72 at -50 mV; 0.33 at -110 mV). These data were forced in a model of the three current components here described, which accurately simulates the behavior observed in the "resting" neuron during membrane migrations in the subthreshold potential range, thereby confirming that active K and Cl conductances contribute to the genesis of membrane potential and possibly to the control of neuronal excitability.

Mutation in the PTEN/MMAC1 gene in archival low grade and high grade gliomas

The PTEN gene, located on 10q23.3, has recently been described as a candidate tumour suppressor gene that may be important in the development of advanced cancers, including gliomas. We have investigated mutation in the PTEN gene by direct sequence analysis of PCR products amplified from samples microdissected from 19 low grade (WHO Grade I and II) and 27 high grade (WHO grade III and IV) archival, formalin-fixed, paraffin-embedded gliomas. Eleven genetic variants in ten tumours have been identified. Eight of these are DNA sequence changes that could affect the encoded protein and were present in 0/2 pilocytic astrocytomas, 0/2 oligoastrocytomas, 0/1 oligodendroglioma, 0/14 astrocytomas, 3/13 (23%) anaplastic astrocytomas and 5/14 (36%) glioblastomas. PTEN mutations were found exclusively in high grade gliomas; this finding was statistically significant. Only two of the PTEN genetic variants have been reported in other studies; two of the genetic changes are in codons in which mutations have not been found previously. The results of this study indicate that mutation in the PTEN gene is present only in histologically more aggressive gliomas, may be associated with the transition from low histological grade to anaplasia, but is absent from the majority of high grade gliomas.

Impact of clinical pathways for total hip replacement: a community-based analysis

The implementation of clinical pathways for total hip replacement was carried out by five hospitals in the metropolitan area of Syracuse, New York. This process occurred under the leadership of clinical nurse specialists and nurse managers. It was supported by preadmission patient education programs and active physician involvement. The participating hospitals shared utilization quality assurance data and benchmarked with respect to the experience of Sacramento, California, and each others' progress. The effort produced substantial reductions in hospital stays without adverse impacts on quality of care.

Evaluation of neuronal loss, astrocytosis and abnormalities of cytoskeletal components of large motor neurons in the human anterior horn in aging

In order to identify possible morphological changes which occur in the anterior horn of normal individuals during aging, 40 controls with no neurological disease were studied. Brain and spinal cord tissue was processed according to a brain banking protocol. Controls were grouped according to age in 10 year intervals. Serial sections (20 microm) of formalin fixed, paraffin-embedded tissue were obtained, from each cervical, thoracic and lumbar spinal cord segment. Every 5th section (until 2 mm) was stained with haematoxylin and eosin and the numbers of motor neurons in the anterior horn counted at x400 magnification. Descriptive statistical analysis was performed using the SPSS program. Parallel sections (5 microm) of the same spinal segments were immunostained with a panel of antibodies including glial fibrillary acidic protein (GFAP), tau, ubiquitin and two phosphorylated neurofilaments subunits. Significant neuronal loss with aging was found by regression line analysis where three equations were used to calculate the number of motor neurons by age in each spinal segment. In 24/40 cases spheroids were observed and they were more numerous in the lumbar segment. GFAP staining revealed a distinctive cellular pattern in the anterior horn of oldest cases. Large and intensely stained astrocytes were seen in the anterior horn of cases aged over 75 years. The number of astrocytes increased progressively with age up to 70 years. Some of the changes observed in the present study may be the result of a selective vulnerability of large motor neurons to aging which could play an important role in the progression of MND. Most of these changes may also have similar pathophysiological mechanisms.

Monoclonal antibodies against vascular endothelial antigens expressed in normal human brain

A panel of monoclonal antibodies reactive with human-brain vessels was raised by immunizing BALB/c mice with homogenate of whole human brain, obtained from temporal lobectomies. Hybridoma supernates were screened by immunohistochemical methods on frozen sections of human brain, liver and spleen and 16 clones were isolated. The pattern of immunoreactivity varied with respect to the type of brain blood vessels predominantly labelled and to tissue specificity. Some antibodies cross-reacted with cow or squirrel monkey forebrain microvessels with an intensity equal to that shown by human brain. The immunoreactivity patterns reflected antigenic heterogeneity among different subsets of vascular endothelial cells in human brain.

Pathology of choroid plexus papillomas: a review

Choroid plexus papillomas (CPPs) are rare, usually slow growing neoplasms. Their biological behaviour cannot be predicted in an individual case. Furthermore, the neuropathological diagnosis of these neoplasms is occasionally difficult because light and electron microscopical and immunohistochemical features may overlap with those of other neoplasms localising in the choroid plexus. The aim of this paper is to review the pathological literature (light and electron microscopy (EM) and immunocytochemistry), to provide guidance on current diagnostic tools and criteria and address the identification of 'atypical' CPPs, e.g. those CPPs with histological features indicative of aggressive behaviour, in an attempt to help bridge the diagnostic gap between benign CPPs on the one hand and choroid plexus carcinomas (CPCs) on the other.

The effects of perilymphatic tonicity on endolymph composition and synaptic activity at the frog semicircular canal

The effects of changes in perilymphatic tonicity on the semicircular canal were investigated by combining the measurements of transepithelial potential and endolymphatic ionic composition in the isolated frog posterior canal with the electrophysiological assessment of synaptic activity and sensory spike firing at the posterior canal in the isolated intact labyrinth. In the isolated posterior canal, the endolymph was replaced by an endolymph-like solution of known composition, in the presence of basolateral perilymph-like solutions of normal (230 mosmol/kg), reduced (105 mosmol/kg, low NaCl) or increased osmolality (550 mosmol/kg, Na-Gluconate added). Altered perilymphatic tonicity did not produce significant changes in endolymphatic ionic concentrations during up to 5 min. In the presence of hypotonic perilymph, decreased osmolality, K and Cl concentrations were observed at 10 min. In the presence of hypertonic perilymph, the endolymphatic osmolality began to increase at 5 min and by 10 min Na concentration had also significantly increased. On decreasing the tonicity of the external solution an immediate decline was observed in transepithelial potential, whereas hypertonicity produced the opposite effect. In the intact frog labyrinth, mEPSPs and spike potentials were recorded from single fibers of the posterior nerve in normal Ringer's (240 mosmol/kg) as well as in solutions with modified tonicity. Hypotonic solutions consistently decreased and hypertonic solutions consistently increased mEPSP and spike frequencies, independent of the species whose concentration was altered. These effects ensued within 1-2 min after the start of perfusion with the test solutions. In particular, when the tonicity was changed by varying Na concentration the mean mEPSP rate was directly related to osmolality. Size histograms of synaptic potentials were well described by single log-normal distribution functions under all experimental conditions. Hypotonic solutions (105 mosmol/kg) markedly shifted the histograms to the left. Hypertonic solutions (380-550 mosmol/kg, NaCl or Na-Gluconate added) shifted the histograms to the right. Hypertonic solutions obtained by adding sucrose to normal Ringer's solution (final osmolality 550 mosmol/kg) increased mEPSP and spike rates, but did not display appreciable effects on mEPSP size. All effects on spike discharge and on mEPSP rate and size were rapidly reversible. In Ca-free, 10 mM EGTA, Ringer's solution, the sensory discharge was completely abolished and did not recover on making the solution hypertonic. These results indicate that perilymphatic solutions with altered tonicity produce small and slowly ensuing changes in the transepithelial parameters which may indirectly affect the sensory discharge rate, whereas relevant, early and reversible effects occur at the cytoneural junction. In particular, the modulation of mEPSP amplitude appears to be postsynaptic; the presynaptic effect on mEPSP rate of occurrence is presumably linked to local calcium levels, in agreement with previous results indicating that calcium inflow is required to sustain basal transmitter release in this preparation.

In vitro effects of GM-CSF on mature peripheral blood neutrophils

GM-CSF can play a crucial role in regulating the neutrophil-mediated inflammatory response. This growth factor is a proliferative stimulus for bone marrow neutrophil stem cell precursors and has at least 3 important roles in regulating neutrophil-mediated immunity: a) a direct effect on the proliferation and development of neutrophil progenitors; b) synergistic activity with other haemopoietic growth factors; c) stimulation of the functional activity of mature neutrophils. The production of GM-CSF may be triggered directly by exogenous factors such as antigens and endotoxins, or indirectly through the release of cytokines by a variety of cells including lymphocytes, activated macrophages and endothelial cells exposed to products of mononuclear phagocytes. Such production of GM-CSF may serve to quickly release mature neutrophils from the bone marrow in response to infections. Moreover, enhancement of the function of mature neutrophils may also augment their ability to migrate to infective sites and then phagocytose and kill pathogens. Increased expression of CD11b/CD18 may play a fundamental part in this mechanism because this receptor is essential for the adhesion of neutrophils to the endothelium. Both phagocytosis and oxidative burst activity increase as a result of the action of GM-CSF and the increased expression of complement- and Fc-receptors can augment opsono-phagocytosis. A further level of neutrophil up-regulation occurs by increasing the functional life span of neutrophils by GM-CSF. Thus, by delaying neutrophil apoptosis, GM-CSF greatly extends the time over which neutrophils may function at inflammatory sites. GM-CSF can thus exert a variety of important regulatory controls of neutrophil function during bacterial infections. Both the number and the functional status of neutrophils is highly regulated by GM-CSF. It is also possible that GM-CSF produced within localised sites of acute inflammation or infection may attract, trap and then activate neutrophils within this site.

Aging and the nigro-striatal pathway

Aging is associated with a progressive impairment in motor function. This feature, together with the decline in mental function, could be considered as an aging syndrome which may finally compromise the ability of the elderly to maintain an active, independent life-style. In the present paper a wide variety of morphological aspects, which have been classically related to brain aging and others such as cytoskeletal changes, the role of growth factors and molecular changes, will be reviewed focusing on aging of the nigrostriatal pathway. In addition to sharing features of aging common to other structures, it is likely that the nigrostriatal pathway has specific characteristics derived from its particular molecular characteristics and/or from a selective vulnerability to aging. To gain further insight into the aging syndrome, the acquisition of rigorous criteria for selecting control cases is paramount. The improvement of methods for the preservation of human tissue is also crucial.

Synaptic current at the rat ganglionic synapse and its interactions with the neuronal voltage-dependent currents

The membrane current activated by fast nicotinic excitation of intact and mature rat sympathetic neurons was studied at 37 degrees C, by using the two-microelectrode voltage-clamp technique. The excitatory postsynaptic current (EPSC) was modeled as the difference between two exponentials. A fast time constant (tau2; mean value 0.57 ms), which proves to be virtually voltage-independent, governs the current rise phase and a longer time constant (tau1; range 5.2-6.8 ms in 2 mM Ca2+) describes the current decay and shows a small negative voltage dependence. A mean peak synaptic conductance of 0.58 muS per neuron is measured after activation of the whole presynaptic input in 5 mM Ca2+ external solution (0.40 muS in 2 mM Ca2+). The miniature EPSCs also rise and decay with exponential time constants very similar to those of the compound EPSC recorded at the same voltage. A mean peak conductance of 4.04 nS is estimated for the unitary event. Deconvolution procedures were employed to decompose evoked macrocurrents. It is shown that under appropriate conditions the duration of the driving function describing quantal secretion can be reduced to <1 ms. The shape of the EPSC is accurately mimicked by a complete mathematical model of the sympathetic neuron incorporating the kinetic properties of five different voltage-dependent current types, which were characterized in a previous work. We show that IA channels are opened by depolarizing voltage steps or by synaptic potentials in the subthreshold voltage range, provided that the starting holding voltage is sufficiently negative to remove IA steady-state inactivation (less than -50 mV) and the voltage trajectories are sufficiently large to enter the IA activation range (greater than -65 mV). Under current-clamp conditions, this gives rise to an additional fast component in the early phase of membrane repolarization-in response to voltage pulses-and to a consistent distortion of the excitatory postsynaptic potential (EPSP) time course around its peak-in response to the synaptic signal. When the stimulation initiates an action potential, IA is shown to significantly increase the synaptic threshold conductance (up to a factor of 2 when IA is fully deinactivated), compared with that required when IA is omitted. The voltage dependence of this effect is consistent with the IA steady-state inactivation curve. It is concluded that IA, in addition to speeding up the spike repolarization process, also shunts the excitatory drive and delays or prevents the firing of the neuron action potential.

Molecular aspects of neuro-oncology

Detailed understanding of molecular events responsible for brain tumor growth is a prerequisite for the development of effective therapeutic modalities leading to improved prognosis and cure. Advances in molecular biology in the past decades have revolutionized our understanding of cancer, including brain tumors. We have learned that abnormal proliferation, inability of the cells to die and their potential to modify their tissue environment result from accumulation of genetic aberrations. This article reviews genetic mechanisms implicated in the pathogenesis of nervous system tumors, such as unactivation of tumor suppressor and replication error genes, generation of abnormal growth factor loops, alterations of apoptotic pathways and angiogenesis.

Cerebellar cortex delayed maturation in sudden infant death syndrome

The cerebellum shows afferent and efferent connections with intrinsic bulbar nuclei and plays an important role in respiration and cardiovascular control. Pathological and neurochemical abnormalities of bulbar nuclei including the arcuate nucleus have been postulated in sudden infant death syndrome (SIDS). Most of these abnormalities have been related to impairment in brain development. The cerebellar cortex has a well-documented evolution from fetal life until infancy; thus, it may be a very good model to assess brain maturation in SIDS. The present study was conducted to investigate changes in the cerebellar cortex in 19 SIDS cases compared with 12 age-related controls using morphological, quantitative, and statistical approaches. Five-microns paraffin sections from the midsagittal cerebellar vermis were stained with hematoxylin and eosin (H&E). Immunohistochemical staining was carried out using a polyclonal antiserum to glial fibrillary acidic protein (GFAP). Each case consisted of a 25-microns parallel paraffin section stained with H&E, where the cerebellar external granular layer (EGL) cell density was obtained in one field magnification (x1,000) using an optical dissector procedure on the basis of a stereological method. A statistically significant high EGL cell density, mostly related to the presence of immature bipolar, elongated neuronal cells of the premigratory zone with hyperchromatic, oval or poor differentiated nuclei, was observed in SIDS. In these cases, EGL expressed immunoreactivity for GFAP mainly in the subpial and the postmitotic zone. These findings demonstrate a delayed or slower decline in the number of EGL neurons in SIDS, suggesting either a prolongation of the growth phase related to postnatal cerebellar foliation or a delay in inward migration. These results suggest that in SIDS there is delayed maturation of the cerebellar cortex/EGL, which may support the hypothesized cardiopulmonary control dysfunction, leading to death in a vulnerable period of postnatal development.

Prognostic analysis of astrocytic gliomas correlating histological parameters with the proliferating cell nuclear antigen labelling index (PCNA-LI)

Eighty out of 250 cases of astrocytic glioma collected from a practice served by a single clinical team over a 15-year period were studied using a full complement of clinical, follow up, histopathological analysis and proliferating cell nuclear antigen (PCNA) immunostaining for the obtention of the PCNA-labelling index (LI). A statistical evaluation and discriminant analysis were carried out with the aim of clarifying the importance of various parameters as predictors of tumor behaviour. Data are correlated with survival (with a 10-year follow up). A significant correlation with survival was found when histological grouping and the PCNA-LI were studied with the Cox test. Most significant features were histological as detected using classical techniques including histological grading. The utilization of objective values (mitosis, cellular density and necrosis) appears to be useful in grading astrocytic tumors. Our results emphasize the importance of cytological, histological and PCNA-LI parameters as predictors of tumor behaviour.