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N Rizzuto

Publications and source records attributed to N Rizzuto.

At least 19 recordsLinked to original sources
PubMed1996

Critical illness myopathy and neuropathy.

BACKGROUND: Critically ill patients may develop muscle weakness or paralysis during the course of sepsis and multiple-organ failure. We studied peripheral nerve and muscle disorders (NMD) in comatose patients. METHOD: Comatose patients who developed paralysis associated with absent deep-tendon reflexes had electroneuromyography (ENMG) and muscle-nerve biopsy specimens taken. Onset and duration of sepsis, multiple-organ dysfunction and failure, biochemical alterations, and drugs potentially interfering with nerve-muscle function were recorded. FINDINGS: 24 patients became quadriparetic or quadriplegic; muscle changes were found in 23. Axonal neuropathy was found in eight of 22 patients examined. All patients had prolonged sepsis and multiple-organ dysfunction, but only 14 had multiple-organ failure. Drugs such as steroids, neuromuscular-blocking agents, and aminoglycosides were not responsible for paresis, and the part played by hyperglycaemia and hypoalbuminaemia is uncertain. Attending physicians predicted a fatal outcome in all cases, although six of seven survivors fully recovered within 115-210 days from the onset of paralysis. INTERPRETATION: Comatose patients may become completely paralysed because of NMD. The diagnosis is important to avoid unnecessary investigations and unreasonably pessimistic prognosis. ENMG is essential for the diagnosis and for planning further clinical management. Biopsy needs to be done only when it is necessary to properly classify NMD.

Biopsy↗
PubMed1996

Stereotactic brain biopsy in human immunodeficiency virus-infected patients.

OBJECTIVE: To evaluate prospectively the diagnostic efficacy and safety of stereotactic brain biopsy and its impact on treatment, outcome, and survival in human immunodeficiency virus-infected patients with focal brain lesions. METHODS: Computed tomography-guided stereotactic brain biopsy was performed in 26 patients, of whom 17 failed to respond to a 2- to 3-week anti- Toxoplasma regimen. Exclusion criteria for biopsy were overt acquired immunodeficiency syndrome for 2 years or longer, Karnofsky score less than 50, and severe coagulopathies. RESULTS: A definitive diagnosis was obtained in 24 patients (92%), of whom 12 (46%) had primary brain lymphoma, six (23%) had progressive multifocal leukoencephalopathy, and four (15%) had Toxoplasma encephalitis. Two thirds of contrast-enhancing lesions on computed tomography were lymphoma and three fourths of contrast-negative lesions were leukoencephalopathy. Three patients had biopsy-related cerebral hemorrhages (morbidity, 11.5%). Median follow-up and survival for the entire group were 24 weeks (range, 6 to 135 weeks). Twenty patients (77%) received specific therapy and 13 (50%) responded to treatment. Of 11 patients with lymphoma undergoing irradiation treatment (whole-brain radiotherapy in seven and gamma-knife treatment in four), nine (82%) had clinical and radiologic response, with a median survival of 34 weeks (range, 13 to 57 weeks). CONCLUSIONS: Stereotactic brain biopsy has high diagnostic efficacy and clinical benefit in carefully selected human immunodeficiency virus-infected patients. The procedure should be performed essentially in patients with contrast-enhancing lesions on computed tomography who have a high frequency of treatable cerebral diseases.

Adult↗
PubMed1996

Sensory involvement in X-linked spino-bulbar muscular atrophy (Kennedy's syndrome): an electrophysiological study.

Electrophysiological findings were studied in a family with spino-bulbar muscular atrophy (SBMA): the subjects were three male patients aged 58, 38 and 34 years and two female carriers aged 63 and 28 years. Diagnosis was proven at the molecular genetic level. Electromyography in the males showed spontaneous activity and neurogenic reorganization of the motor unit; motor nerve conduction was normal. Sensory action potentials were variably reduced in amplitude, but some were completely normal. Somatosensory evoked potentials, from both the upper and lower limbs, were invariably abnormal because involvement of the central pathways was observed. These findings are in agreement with histological investigations documenting lesions in the posterior columns. Brain-stem acoustic evoked potentials showed an increase in wave I latency. The electrophysiological data provide further evidence of the extent of sensory damage either in the central or the peripheral nervous system in SBMA patients, who otherwise have a constant clinical presentation of progressive motor neuron disease.

Adult↗
PubMed1995

A common beta hexosaminidase gene mutation in adult Sandhoff disease patients.

beta-Hexosaminidase gene mutations were analyzed in two adult-onset Sandhoff disease Italian patients by PCR analysis of a common known mutation (delta 5') and by heteroduplex analysis of genomic and RT-PCR DNA fragments, covering the whole gene. The patients' genotypes were delta 5'/C1214%, and G890A/C1214T, respectively. As mutation C1214T (Pro405Leu) is also present in the other two late-onset cases so far described, we suggest that C1214T is a common mutation in this type of Sandhoff disease. Mutation G890A (Cys297Tyr) is a novel mutation which presumably causes altered processing of the pro beta chain.

Adult↗
PubMed1995

Role of HIV in the pathogenesis of distal symmetrical peripheral neuropathy.

We report the results of a clinical, electrophysiological and pathological study conducted in 18 AIDS patients presenting a distal symmetrical predominantly sensory polyneuropathy (DSPN) characterized by painful dysesthesias as main complaint. Onset of the neuropathy was at CDC (Center for Disease Control) stage II in 2 patients, at CDC stage III in 5 patients and at CDC stage IV in the remainder. Electrophysiological investigation confirmed the presence of an axonal alteration in the sensory nerves, but also revealed motor involvement in all cases. The neuropathological features of sensory nerves were fiber loss and axonal degeneration with macrophagic activation. The expression of monocyte-macrophage markers and of major histocompatibility complex class II antigens appeared up-regulated in endoneurial ramified cells, while expression of CR3, a complement receptor involved in the process of phagocytosis, was down-regulated. In six nerve biopsy samples and in two out of five DSPN dorsal root ganglia we found HIV-related mRNA and protein located in scattered cells of the endoneurium which we presume to be macrophages. These data suggest that: (a) DSPN may occur early in the course of the disease and is not limited to later stages; (b) DSPN is not a ganglionitis but is actually a sensory-motor neuropathy; (c) the virus enters the peripheral nervous system and induces changes in the immunocompetent cell population with activation of macrophages. Storage of the virus inside macrophages may act both as a reservoir for the virus and as a putative cause of nerve damage, probably through release of cytotoxins and/or interaction with trophic factors.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Brain metastases from post-radiation malignant peripheral nerve sheath tumour.

A 45-year-old female patient developed a malignant peripheral nerve sheath tumour (MPNST) arising from the left brachial plexus, ten years after regional radiation treatment for Hodgkin's disease. The clinical course was characterized by local recurrence, pulmonary and cerebral metastases with endocranic hypertension syndrome, and the death of the patient 18 months after the onset of symptoms. The tumour presented a histopathological picture of schwannoma with a high grade of malignancy. A particular feature of this case was the exceptional occurrence of the early and massive invasion of the brain.

Brain Neoplasms↗
PubMed1995

Systemic passive transfer studies using IgM monoclonal antibodies to sulfatide.

We present a patient with benign IgM-gamma anti-Sulfatide (SUL) whose neuropathy was transferred in newborn rabbits. The patient's clinico-pathological picture of anti-SUL-associated demyelinating neuropathy is reported. The monoclonal IgM antibodies prepared by Tatum's method, that retained their biological activity, were passively transferred to newborn rabbits. The passive transfer produced demyelinating nerve lesions very similar to the donor antibody neuropathy. In experimental lesions we observed the human IgM anti-SUL antibodies binding to Schmidt-Lanterman incisures and nodes of Ranvier. We postulate that the myelin-specific and complement-dependent lesions observed in the peripheral nerve support the potential demyelinating role of anti-SUL antibodies. Moreover, the pattern of the antibody binding to the perineuronal sheath of satellite cells in dorsal root ganglia strengthen the hypothesis that anti-SUL antibodies may have a pathogenetic role in this sensorimotor syndrome.

Aged↗
PubMed1995

Tau protein immunolocalization in fetal and adult human spinal cord.

In the present study, the monoclonal antibody Alz-50 has been used to determine and compare the immunohistochemical localization of phosphorylated tau proteins in the developing and normal adult spinal cord. At all stages of fetal life Alz-50 fiber immunoreactivity was observed in the dorsal roots, in the dorsal and dorsolateral funiculi, and in restricted regions of the dorsal horn. Alz-50 immunoreactivity was also demonstrated in the dorsal root ganglion neurons. In the adult spinal cord a consistent pattern of Alz-50 fiber immunoreactivity was localized in the superficial layers of the dorsal horn (lamina I and II) but not in dorsal and dorsolateral funiculi and in the dorsal root ganglion. Comparable results in fetal specimens have been obtained employing PHF-1, a monoclonal antibody generated against paired helical filament proteins from Alzheimer brains, while no significant immunostaining for PHF-1 was observed in the adult spinal cord. In addition, the staining with monoclonal and polyclonal anti-tau antibodies overlapped with that of Alz-50. The transient, selective pattern of Alz-50 and PHF-1 immunoreactivity may disclose some relevant functions of tau proteins during somatosensory pathway development.

Adult↗
PubMed1995

Autoimmune paraneoplastic cerebellar degeneration: immunohistological localization of antibody-binding sites.

Sera from 3 patients with breast or ovarian tumors and paraneoplastic cerebellar degeneration (PCD) contained anti-Purkinje cell antibodies (PCAbs) which also bind to other neurons on frozen sections of adult rodent brain. PCAbs tested on new-born rodent (rabbit, rat, mouse) brain tissue detected only oligodendrocyte-like cells (ODLC) in the white matter and allowed us to speculate on the nature of the antigenic structure in the neuronal cytoplasm. All these PCAbs appear histochemically identical and recognize antigens which belong to so-called "Yo" proteins.

Adenocarcinoma↗
PubMed1995

Experimental induction of myelin changes by anti-MAG antibodies and terminal complement complex.

We investigated the role of anti-myelin-associated glycoprotein (MAG) IgM and complement (C) in the pathogenesis of myelin alterations occurring in patients with anti-MAG-associated polyneuropathy. For this purpose, we separately studied the effects of anti-MAG antibodies and terminal C complex (TCC) after injection into the rabbit sciatic nerve. The two different local treatments produced identical ultrastructural abnormalities such as intramyelinic edema, myelin vesiculation and, in particular, separation of the major dense lines with the formation of widely spaced myelin, a peculiar feature encountered in human peripheral nerve disorders with circulating anti-myelin monoclonal IgM. In nerves treated with anti-MAG IgM ultrastructural myelin alterations were concurrent with activation of the rabbit's own C to the formation of TCC. Contrary to the immunological and ultrastructural findings obtained in C-sufficient animals, in C6-deficient rabbits injected with anti-MAG IgM no myelin alterations nor C completion were observed. This study identifies anti-MAG IgM as the mediator and the C as the effector of myelin changes observed in the present model and, for extension, in human neuropathies associated with anti-MAG IgM.

Animals↗
PubMed1995

Expression and distribution of GAP-43 in human astrocytes in culture.

By combining mRNA analysis and immunocytochemistry, we investigated the expression of the growth associated protein 43 (GAP-43) in enriched populations of astrocytes, obtained from mixed cultures of human fetal brains. Total cellular RNA was extracted from cell pellets and reverse transcribed into cDNA; cDNA was subjected to PCR amplification using primers specific for GAP-43 and PCR products were separated through polyacrylamide gels. Double immunofluorescence staining was performed on dissociated cell cultures using antibodies to glial fibrillary acidic protein (GFAP) and to GAP-43. Results showed that both transcription and translation for GAP-43 occur in cultured astrocytes. GAP-43 immunoreacting material was detected in the cell processes and diffusely in the cytoplasm of GFAP-positive astrocytes, during early stages of maintenance in vitro. In older cultures, GAP-43 immunoreactivity persisted in a large percentage of cells, with a tendency to accumulate in perinuclear areas. These observations provide evidence that GAP-43 is not restricted to neuronal cells. The close spatial association with cytoskeletal constituents, as observed in astrocytes, suggests a role for this protein in the control of cell shape, motility and adhesion processes.

Astrocytes↗
PubMed1994

Microgyria associated with Sturge-Weber angiomatosis.

A case is reported of an infant affected with Sturge-Weber disease who underwent left hemispherectomy due to untreatable seizures when 97 days old. Pathological analysis of the surgical specimens revealed the presence of four-layered microgyric cortex below the angiomatosis, intense gliosis, and the presence of calcifications of both the abnormal cortex and the underlying white matter. These findings suggest that the early infantile form of Sturge-Weber disease is associated with a developmental disorder of the cortical organization. Such abnormalities are consistent with the presence of an epileptogenic condition that is unresponsive to pharmacological treatment.

Atrophy↗
PubMed1994

Pattern of nervous tissue immunostaining by human anti-glycolipid antibodies.

Immunostaining of human, bovine and rodent unfixed nervous tissue sections was performed in order to characterize the structures recognized by anti-glycolipid antibodies. Four human sera from patients, two with M-IgM and motor neuron syndrome or motor neuropathy and two with motor neuropathy and polyclonal IgG antibody activity against gangliosides (GL; i.e. GM1, GD1b, GD1a), were utilized. Serum from a patient with sensory neuropathy and M-IgM immunoglobulins with antibody activity against sulfatide (SUL) was included in this series. This study shows that polyclonal and monoclonal anti-glycolipid antibodies give three different patterns of staining. The first is cholera toxin-like showing a more restricted neuronal pattern of staining. The second is peanut agglutinin-like, which includes the carbohydrate epitope shared by a group of glycoproteins in the gray and white matter. The third (anti-SUL) gives a preferential myelin staining. However, sera with anti-GM1 and anti-SUL antibodies recognize a number of closely situated determinants in the gray matter of the spinal cord and in the granule cells, while in peripheral nerves or in neuronal cells in culture their binding produces a different pattern (nodes of Ranvier for anti-GL; myelin for anti-SUL). These findings indicate that immunohistochemistry with anti-GL and anti-SUL antibodies may provide information regarding the glycolipid-bearing anatomical structures as target antigens and further substantiate the role of these molecules in the pathogenesis of autoimmune neurological disorders.

Amyotrophic Lateral Sclerosis↗
PubMed1994

Spinal somatosensory evoked potentials in patients with tethered cord syndrome.

We studied the electrophysiological changes occurring in six patients with tethered cord syndrome. Evidence of spinal malformations was provided by magnetic resonance imaging. The functional assessment of the spinal cord was performed by analysing both spinal and cortical somatosensory evoked potentials. The evoked electrospinogram was recorded from the thoracic and lumbosacral spinous processes. The N22 lumbosacral potential was selectively affected, being rostrocaudally displaced and reduced in amplitude or even absent in patients with neurological signs indicating a segmental lower cord lesion. Inter-peak somatosensory evoked potentials latency was normal in all cases, suggesting that ascending axonal potentials in the dorsal column fibres may be synchronized. Segmental potentials of the lumbosacral response, originating from the post-synaptic activity of dorsal horn interneurons, are selectively affected in this syndrome resulting from the rostrocaudal displacement of the spinal cord due to tethering. Our findings in the clinical field are consistent with previous experimental evidence indicating a different sensitivity of the gray vs. white matter to progressive stretching.

Adult↗
PubMed1993

Clinical spectrum of the tomaculous neuropathies. Report of 60 cases and review of the literature.

Tomaculous neuropathy has a distinctive pathological pattern of myelin thickenings in a high proportion of internodes but no specific pattern of nerve degeneration. We have analyzed the variable clinical expression of this disorder in a large series of patients. Different phenotypes have been recognized: the majority of our patients (52 cases) had hereditary neuropathy with liability to pressure palsy (HNPP) showing wide variability of clinical progression and of severity of the single episodes. 3 patients suffered from familial recurrent brachial plexus neuropathy (FBPN); 5 patients had a symmetrical progressive sensorimotor involvement of the limbs (SSMN), predominantly in the distal portions and leading to permanent disability. The explanation for this clinical variability does not emerge from our data or from the literature. Segmental demyelination is the major change correlating with the episodes of nerve palsy; axonal degeneration might be rarely associated. The myelin sausages are the markers of a selective vulnerability of the nerve fibers either to mechanical injury or to some other unknown event.

Adolescent↗