The role of language areas in motor control dysfunction in Parkinson's disease

We evaluated the differences in motor control organization between parkinsonian patients with (seven cases) and without (ten cases) gait disorder. We used positron emission tomography (O15-H2O-PET) to measure regional cerebral blood flow as a correlate for local neuronal activation. This has been assessed during repetitive joystick movements of the right hand, externally triggered using a metronome as an auditory cue. In patients with Parkinson's disease (PD) without gait disorder, the contralateral supplementary motor cortex and the bilateral cerebellum were activated, while in PD patients with gait disorder the contralateral Broca's area, the contralateral sensory motor cortex and the homolateral cerebellum were activated. Our results suggest that PD patients with gait disorder creates an internal verbal cue in order to control the output of the movement of joystick, supplying the loss of control of the supplementary motor cortex that is activated in patients without gait disorder.

CDKN2A/p16 inactivation in the prognosis of oligodendrogliomas

The cell-cycle regulator p16 inhibits the complex cdk4-cyclin D1 and controls G1-S transition. In human tumors, p16 inactivation is often accomplished by homozygous deletion (HD) of its encoding gene, CDKN2A. Methylation of the 5' CpG island promoter has been proposed as an alternative mechanism of inactivation. Expression of p16, CDKN2A HD and 5' CDKN2A CpG island methylation was studied in 25 oligodendrogliomas by immunohistochemistry and PCR amplification. Ten oligodendrogliomas were p16-immunonegative, and CDKN2A HD was determined in 8 of these cases. In the 2 immunonegative cases without HD, no CpG island methylation was found. The absence of CpG island methylation in the p16-immunonegative cases without HD suggests either non-genetic regulation of p16 or different genetic changes. CDKN2A HD did not correlate with histological grading (p = n.s.); however, it showed a correlation with survival (p = 0.03), supporting an important role of CDKN2A in the prognosis of oligodendrogliomas.

Dehydroepiandrosterone prevents oxidative injury induced by transient ischemia/reperfusion in the brain of diabetic rats

Both chronic hyperglycemia and ischemia/reperfusion (IR) cause an imbalance in the oxidative state of tissues. Normoglycemic and streptozotocin (STZ)-diabetic rats were subjected to bilateral carotid artery occlusion for 30 min followed by reperfusion for 60 min. Rats had either been treated with dehydroepiandrosterone (DHEA) for 7, 14, or 21 days (2 or 4 mg/day per rat) or left untreated. Oxidative state, antioxidant balance, and membrane integrity were evaluated in isolated synaptosomes. IR increased the levels of reactive species and worsened the synaptic function, affecting membrane Na/K-ATPase activity and lactate dehydrogenase release in all rats. The oxidative imbalance was much severer when transient IR was induced in STZ-diabetic rats. DHEA treatment restored H2O2, hydroxyl radical, and reactive oxygen species to close to control levels in normoglycemic rats and significantly reduced the level of all reactive species in STZ-diabetic rats. Moreover, DHEA treatment counteracted the detrimental effect of IR on membrane integrity and function: the increase of lactate dehydrogenase release and the drop in Na/K-ATPase activity were significantly prevented in both normoglycemic and STZ-diabetic rats. The results confirm that DHEA, an adrenal steroid that is synthesized de novo by brain neurons and astrocytes, possesses a multitargeted antioxidant effect. They also show that DHEA treatment is effective in preventing both derangement of the oxidative state and neuronal damage induced by IR in experimental diabetes.

[Isolation of Listeria spp., Aeromonas spp., and Vibrio spp. from seafood products]

Forty-one strains of Listeria, Aeromonas and Vibrio have been isolated in 71 samples of seafood, both raw and ready to eat and frozen. L. monocytogenes, detected by PCR also, is found in the smoked salmon only. Aeromonas spp. and Vibrio spp. are isolated in the raw products (shrimps and shellfish). No relationship is found between the presence of such microrganisms and the common indicator bacteria. Finally, the health hazard related to strong contamination and the need to diversify the food safety assurance programmes, for the various products, are underlined.

An Italian family with Ala-47 transthyretin mutation associated with cardiomyopathy and polyneuropathy

We describe two Italian first cousins with familial amyloidotic polyneuropathy associated with transthyretin variant consisting of the substitution of alanine for glycine at codon 47 (TTR Ala-47), from a family with a history of cardiac failure. The 40-year-old patient presented with autonomic dysfunction and the 44-year-old cousin with congestive heart failure. Both developed sensorimotor and autonomic polyneuropathy. Since a similar clinical picture has been described in another Italian family, the cardiac involvement must be regarded as a salient and early feature of the TTR Ala-47 mutation.

Mutations and immunohistochemistry of p53 and proliferation markers in astrocytic tumors of childhood

Thirty cases of hemispheric astrocytic tumors of childhood, consisting of 11 pilocytic astrocytomas, 2 fibrillary astrocytomas, 9 anaplastic astrocytomas, and 8 glioblastomas, were studied for the presence of p53 mutations and for immunohistochemical demonstrations of p53 and proliferation markers PCNA and Ki-67 MIB-1. The study was performed using polymerase chain reaction (PCR)-assisted single-strand conformation polymorphism analysis of exons 5-8 and direct sequence analysis of PCR products. For immunohistochemistry, DO1 and PAb 1801 were used. No mutation and no positivity for p53 protein were found in pilocytic astrocytomas. Mutations (at codons 144, 202, and 245) were found in 2 out of 8 glioblastomas and in 1 out of 9 anaplastic astrocytomas, whereas positive staining was found in 11 out of 17 malignant gliomas. Cases with mutations showed the highest p53 labeling index and also PCNA and MIB-1 labeling indices. The negative results in pilocytic astrocytomas are in line with the benign course of these tumors, whereas for malignant gliomas no difference seems to exist in comparison with adult cases.

Control of meningioma cell growth by platelet-derived growth factor (PDGF)

We have examined the possible involvement of PDGF and PDGF receptors in the growth control of five meningiomas, analyzing the biopsy specimens and the primary cultures derived from the same tumors. Light and electron microscopy demonstrated that MAbs against PDGF beta-receptors immunodecorate meningioma cells in vivo and in vitro, while those against alpha-receptors gave negative results. The effects of PDGF isoforms AA, AB, BB and of PDGF neutralizing antibodies on meningioma cultures were examined using [3H]thymidine incorporation analysis. Only with PDGF-AB and -BB a mitogenic effect was observed, while PDGF-neutralizing antibodies produced a reduction of [3H]thymidine incorporation. The production of PDGF-like growth factors by meningioma cells was tested analyzing the effects of meningioma culture-conditioned media on the growth of Swiss 3T3 cells. In all cases meningioma conditioned media stimulated the in vitro growth of 3T3 fibroblasts and this stimulatory effect was strongly reduced by PDGF-neutralizing antibodies. Furthermore, Northern blot analysis demonstrated expression of c-sis/PDGF-B and PDGF beta-receptors mRNA in all meningioma biopsies and in all the derived cultures. Our results provide strong evidence that PDGF-B chain and PDGF beta-receptors are involved in growth control mechanisms of human meningiomas through autocrine and/or paracrine mechanisms.

Carotid pain during percutaneous angioplasty (PTA). Pathophysiology and clinical features

Stretching of the internal carotid artery during percutaneous transluminal angioplasty (PTA) may be associated with transient neck, facial or cranial pain. We report a series of 53 cases who received PTA. Cervical pain occurred in 51% of patients, with a radiation to face and scalp in 33%. Analysis focused on: (a) description of pain intensity, quality, timing and location; (b) investigation about the role of individual and technical parameters that could influence the relative risk of pain onset during PTA; (c) comparison with other available data on pain syndromes related to the carotid artery. Intimal flapping on post-angioplasty angiograms, bradycardia during the procedure and previous history of AMI were associated with a higher risk of painful angioplasty. PTA may also serve as a tool to investigate carotid pain and may add further knowledge to the evidence available about the role of the carotid wall in the pathogenesis of facial and cranial pain.

Tumor cell proliferation and apoptosis in medulloblastoma

The distribution of proliferating cell nuclear antigen (PCNA)-(clone PC 10)- and Ki-67-(clone MIB-1)-positive nuclei was investigated in 60 medulloblastomas of childhood. Although the labeling index of the two markers did not coincide, both showed a wide range of parallel variations. The percentage of positive nuclei was similar in both classic and desmoplastic tumors. A variable proliferation capacity was found in the different tumor structures. Areas with neuronal and glial differentiation showed very few positive nuclei; these were very abundant in the infiltration areas, and along penetrating vessels from subarachnoidal growths. Pale islands were negative or positive only in their peripheral part. Large-cell areas were richer in positive nuclei than classic ones, accounting for their more malignant character. Hyperchromatic round nuclei, not belonging to necrotic foci and called lymphocyte-like nuclei, differently interpreted in the past, were variably found in every case. They are known, from previous experience, to stain orange with Acridine Orange fluorochroming, like single-stranded DNA. They were not easily distinguishable from mitoses and were stained by in situ end-labeling of DNA strand breaks, as demonstrated by incorporation of labeled nucleotides. They were regarded as possible apoptotic nuclei, representing either a peculiar type of cell death or the preservation of the cell deletion capacity, typical of the embryonal tissue of origin.

Haemodynamic changes following carotid occlusion: MRI angiography and transcranial Doppler patterns

To see the signal changes in MR angiography (MRA) when occlusions or severe stenoses of carotid arteries occur and to relate these data with the velocity values provided by transcranial Doppler sonography (TCD), 20 patients showing symptomatic or asymptomatic unilateral carotid obstructions underwent both MRA and TCD after digital angiography investigation. No MRA signal was recorded immediately downstream from the carotid occlusion. Low flow velocity values in the carotid siphon and middle cerebral artery (MCA) ipsilateral to the carotid obstruction were associated with altered MRA signals corresponding to the same vessels. Turbulence phenomena induced by reversed flow in the anterior cerebral artery induced MRA signal impairments. In carotid occlusions, there may be a relationship between the MRA patterns and the flow velocity variations detected by TCD, but the two approaches have to be applied together since they provide complementary information.

Coexpression of platelet-derived growth factor (PDGF) B chain and PDGF B-type receptor in human gliomas

In this study we analyzed the expression of mRNA for PDGF-B and PDGF B-type receptor (PDGFrecB) in 42 biopsy specimens from human astrocytic gliomas and other brain tumors. All gliomas expressed PDGF-B mRNA at higher levels than found in peritumoral and normal nervous tissues. Levels of PDGF-B transcripts correlated strongly with those of mRNA for glial fibrillary acidic protein. Thus, the production of PDGF-B mRNA may be attributed mainly to tumoral glial cells. PDGFrecB transcripts were found in 24 out of 29 gliomas, in agreement with the hypothesis of an autocrine growth stimulation in these tumors. Moreover, mean levels of PDGFrecB expression were higher in glioblastomas than in astrocytomas and over 30-fold higher in meningiomas than in gliomas. This suggests that in gliomas PDGFrecB can be expressed also by vascular elements, in agreement with the hypothesized existence of a paracrine mechanism that may be responsible for the endothelial hyperplasias.

Cerebellar syndrome in adult celiac disease with vitamin E deficiency

We studied a woman with adult onset celiac disease complicated by a cerebellar syndrome that progressed despite the resolution of the malabsorption symptoms with a gluten free diet. The patient presented vitamin E deficiency and the cerebellar symptoms improved with vitamin E therapy. This case supports the possible role of this deficiency in the development of the neurological complications of celiac disease.

Epidural anesthesia as an adjunct to retroperitoneal aortic surgery

Recent developments in vascular surgery suggest that the retroperitoneal approach to the aorta and the use of epidural anesthesia for lower limb revascularization are associated with decreased morbidity and shorter hospital stays. By combining these principles, we sought to determine if retroperitoneal aortic surgery could be performed under epidural anesthesia and if this might be advantageous. Over a 16-month period, 57 patients underwent aortic surgery via the retroperitoneal (n = 33) or transperitoneal (n = 24) approach. In the former, epidural anesthesia was employed in 10 patients, general anesthesia in 3, and combined epidural anesthesia and general anesthesia in the remaining 20. In the transperitoneal group, general anesthesia was employed in 21 patients and combined epidural anesthesia and general anesthesia in 3. Both groups were similar in age and gender, but risk factors were predominant in the retroperitoneal group. With the exception of one death due to aspiration, there were no significant differences between the transperitoneal and retroperitoneal groups with respect to overall morbidity, pulmonary complications, and length of stay in the intensive care unit and hospital. Despite these findings, we favor the combination of epidural and general anesthesia for retroperitoneal aortic surgery. Morbidity was significantly decreased (p less than 0.05) in low-risk retroperitoneal patients when combined epidural anesthesia and general anesthesia were employed.

Oncogenes and growth factors in gliomas

The activation of cellular proto-oncogenes is related to the genesis and progression of neoplasias. Protein growth factors and their cellular receptors have been identified as products of some proto-oncogenes. The role of epidermal growth factor receptor (EGFr) in gliomas is presented. The expression of mRNA for platelet-derived growth factor (PDGF) and PDGF B-type receptor (PDGF-rec-B) in gliomas is analyzed. Gliomas express "in vivo" PDGF.B and PDGF-rec-B mRNAs. PDGF.B mRNA levels correlate with GFAP mRNA and does not correlate with the degree of malignancy. This is in agreement with the hypothesis of an autocrine growth stimulation in gliomas. However some findings seem to indicate that in these tumors the PDGF-rec-B is preferentially expressed by vascular elements. Thus, also a paracrine loop for endothelial cell growth stimulation may be suggested in malignant gliomas.

Preferential expression of the dbl proto-oncogene in some neuroectodermal tumors

The dbl oncogene belongs to a unique class of human transforming genes. The dbl proto-oncogene is activated by substitution of the 5' portion of the gene with an unrelated human sequence. The proto-oncogene product is distributed between the soluble and membrane fractions of the cytoplasm and its function remains still unknown. In order to understand the biological role of dbl in human malignancies or during cell differentiation we have investigated the expression of the dbl oncogene in a wide number of human tumors of different embryological derivation. We found that dbl is preferentially expressed in a few neoplastic histiotypes of neuroectodermal origin. The transcript size of 5.3 Kb strongly suggests that the gene is not truncated in these tumors. These data, together with the information that the proto-oncogene has been found expressed in normal brain and adrenal medulla, indicate that dbl expression may be involved in cell differentiation of some tissues of neuroectodermic origin.

Vascular response to irradiation in malignant gliomas

The vascular response to irradiation was studied in peritumoral cortex and tumor areas in 9 autopsied cases of glioblastoma multiforme and in 10 biopsies of reoperated cases. The study was carried out by histological, immunohistochemical and electron microscope procedures. Hyaline thickening of the vessel walls with deformation and impoverishment of endothelial nuclei are the most striking features. Formation of large PAS-positive areas from the confluence of thickened vessel walls and development of a fibroblastic proliferation follow. Fibroblastic areas may entrap tumor glial cells. In PAS-positive areas a special population resembles myofibroblasts of tissue scars. Electron microscope reveals the production of collagen fibrils in and outside vessel walls. The presence of collagen III and IV is in line with the present interpretation of the mesodermic component.

The vascular response to tumor infiltration in malignant gliomas. Morphometric and reconstruction study

Neo-vascularization and endothelial hyperplasia have been shown to be very active in malignant gliomas. In this contribution the vascularization of the cortex infiltrated by malignant gliomas is morphometrically studied and the endothelial proliferations are immunohistochemically investigated and reconstructed by a three-dimensional computer-assisted procedure. Vessel density increases after tumor infiltration in some cases only. The diameter of vessels increases and so does the number of nuclei/vessel after the complete invasion of the cortex when vascular glomeruli develop. In completely infiltrated cortex with development of glomeruli and circumscribed necroses, vessel density is very low. No neoformation of vessels takes place before the complete infiltration of the cortex by the tumor. The hyperplastic formations, usually arranged parallel to the deep or outer cortical layers, take origin from the radially penetrating vessels from the meninges and their lateral branching. The hyperplasia deforms the vascular network, making it often inadequate to supply tumor cells. Immunohistochemically, the cells composing the hyperplastic structures are variably positive for factor VIII/RAg and, at a lesser extent, for alpha-smooth muscle actin. The poorness of the vascular network in many instances of completely infiltrated cortex is responsible for the development of circumscribed necroses.

Membrane currents of rat satellite cells attached to intact skeletal muscle fibers

Muscle satellite cells play an important role in the postnatal growth of skeletal muscle and in the regeneration of damaged muscle during adult life. Little is known about the physiological properties of satellite cells in their dormant state as they lie adjacent to the intact muscle fibers, underneath the basement membrane. Our recent experiments, using patch clamp techniques, indicate that no tight electrical coupling is present between satellite cells and the muscle fiber dissociated from rat flexor digitorum brevis. Satellite cells possess sodium channels with low sensitivity to tetrodotoxin and at a much lower density than muscle. In addition, satellite cells are insensitive to acetylcholine (ACh) for at least 24 hr after having been removed from the animal, even when detached from their muscle fiber. However, we could measure ACh-evoked currents from satellite cells 48-72 hr in culture, indicating that ACh sensitivity develops with time.

Voltage gating of conductance in lipid bilayers induced by porin from outer membrane of Neisseria gonorrhoeae

Porins, polypeptides of approximately 35 kDa, are present as integral membrane proteins in the outer membranes of a variety of Gram-negative bacteria. As reported previously for a purified porin from Escherichia coli, voltage gating of conductance was found to be induced in a lipid bilayer by the solubilized purified porin, protein I, from Neisseria gonorrhoeae. The unitary response to an applied potential showed a cascade of current from an initial level through at least three levels, more or less equal, to a persisting lower level. The initial level of current corresponded to 1.0-1.3 nS for 0.2 M NaCl on either side of the bilayer. Briefly reducing the potential to zero restored the current to its initial level. Interpretation of the unitary response is suggested by electron microscopic data obtained on negatively stained outer membranes of E. coli indicating the presence of "pores" appearing in triplets. Moreover, low-resolution x-ray and neutron diffraction studies on crystals obtained with an E. coli porin show that three polypeptides associate to form a unit. Combining such structural data with the present electrical data lends support for the hypothesis that the unitary response results from three pores acting as a unit in response to an applied potential. Evidence obtained with the patch-clamp technique is mounting for a similar mechanism of many channels operating as a unit in a variety of cell membranes. The porin channel holds promise as a concrete model for the analysis of voltage gating of ionic conductance.