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Biomedical subjects

F Fenzi

Publications and source records attributed to F Fenzi.

13 recordsLinked to original sources
PubMed2001

Glial cell and macrophage reactions in rat spinal ganglion after peripheral nerve lesions: an immunocytochemical and morphometric study.

Following peripheral nerve injury perineuronal satellite cell reaction in the corresponding spinal ganglion is observed. The mechanisms underlying the glial responses to axon injury remain unknown. In an immunocytochemical and morphometric study we investigated satellite cell and macrophage responses in the rat L4 and L5 dorsal root ganglia (DRG) during the seven days immediately after unilateral sciatic nerve crush or transection. Nerve lesion induced a significant increase of glial fibrillary acidic protein-immunoreactive (GFAP-IR) cells in the ipsilateral L4-L5 DRGs. The number of ED1-positive macrophages significantly increased as well. We found no significant differences between the increases provoked by the two types of nerve lesion, but the macrophage activation was detected earlier after nerve transection than after crush. No correlation was detected between satellite cells and macrophages reactions over the 7 day period we examined. These findings support the idea that intercellular neuron-glial diffusible signals play a major role in DRG glial cell response to peripheral nerve lesion.

Animals↗
PubMed1999

Phenotype of the tomato high pigment-2 mutant is caused by a mutation in the tomato homolog of DEETIOLATED1.

Tomato high pigment (hp) mutants are characterized by their exaggerated photoresponsiveness. Light-grown hp mutants display elevated levels of anthocyanins, are shorter and darker than wild-type plants, and have dark green immature fruits due to the overproduction of chlorophyll pigments. It has been proposed that HP genes encode negative regulators of phytochrome signal transduction. We have cloned the HP-2 gene and found that it encodes the tomato homolog of the nuclear protein DEETIOLATED1 (DET1) from Arabidopsis. Mutations in DET1 are known to result in constitutive deetiolation in darkness. In contrast to det1 mutants, tomato hp-2 mutants do not display any visible phenotypes in the dark but only very weak phenotypes, such as partial chloroplast development. Furthermore, whereas det1 mutations are epistatic to mutations in phytochrome genes, analysis of similar double mutants in tomato showed that manifestation of the phenotype of the hp-2 mutant is strictly dependent upon the presence of active phytochrome. Because only one DET1 gene is likely to be present in each of the two species, our data suggest that the phytochrome signaling pathways in which the corresponding proteins function are regulated differently in Arabidopsis and tomato.

Amino Acid Sequence↗
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↗
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↗
PubMed1993

Clinical features of Kleine-Levin syndrome with localized encephalitis.

We report the clinico-pathological findings regarding a 9 year-old girl with some clinical features of Kleine-Levin syndrome who died suddently as a result of pulmonary embolism in the course of femoro-iliac thrombophlebitis. Neuropathological examination provided evidence of perivascular inflammatory infiltrates and microglial proliferation of nodular type located in the diencephalon and midbrain. These findings suggest that a localized encephalitis may be the underlying condition in Kleine-Levin syndrome.

Brain Mapping↗
PubMed1988

Peripheral neuropathy associated with allergic granulomatous angiitis (Churg-Strauss syndrome): clinical features and histological findings.

We describe the case of a patient with a history of resistant asthma who presented with subacute neuropathy, hypereosiniphilia and central nervous system involvement; these findings were consistent with allergic granulomatous angiitis (Churg-Strauss syndrome). Although cutaneous biopsy prompted the diagnosis, the cases reported suggests that clinical, biological and histological data are all essential for the diagnosis. We emphasize that an early recognition of this syndrome may be important, since appropriate therapy may lead to recovery or influence favorably at least long term survival.

Aged↗
PubMed1988

Anatomical and clinical study of a case of subacute encephalomyelitis with hyperekplexia syndrome.

This case of subacute encephalomyelitis with a hyperekplexia type syndrome was characterized histologically by marked lymphomonocytic infiltrates, nodules of microglia, evidence of neuronophagia. These findings suggested a viral infection. The clinical peculiarities of this encephalomyelitis are explained by the elective site of the lesions in the grey substance of the spinal cord, of the tegmentum of the medulla oblongata and pons and of some nuclei of the extrapyramidal system.

Acoustic Stimulation↗
PubMed1983

Histopathological and ultrastructural study of a case of infantile metachromatic leukodystrophy.

The histopathological and ultrastructural findings on a nerve biopsy specimen and on a CNS necropsy specimen in a case of IML with a typical clinicaL course are reported. Nerve biopsy once again proved to be a sure diagnostic guide even at an early stage of the disease. Some differences in the fine structure of the cytosomes between the nerve biopsy and CNS necropsy material studied four years later may be due to the different rates of catabolism of the constituent lipids as well as to post mortem artefacts.

Brain↗
PubMed1982

Congenital toxoplasmosis: histological and ultrastructural study.

A case of congenital toxoplasmosis is reported in which the patient died at 32 days following seizures, coma and respiratory disturbances. Neuropathological examination showed numerous foci of softening throughout the brain. Histological examination disclosed widespread areas of inflammatory necrosis. Circumscribed areas of granulomatous inflammation were also found. Cysts containing a variable number of microorganisms and toxoplasmas free in the damaged areas were frequently observed. Small calcifications were scattered in the cerebral cortex and basal ganglia. Electron microscopy of postmortem brain specimens demonstrated toxoplasmas at various stages of development. The microorganism is enveloped by a two-layered membrane, the pellicle. Replication occurs in a vacuole inside the host cell. Following replication the newly formed parasites, the trophozoites, are released. Several replications without release may also occur with consequent cyst formation. The motile form of the toxoplasma, the tachyzoite, is fusiform with truncated cone shape of the anterior ending which is the presenting surface modified for host cell penetration. The modality of transplacental transmission and the clinical syndromes associated with toxoplasma infection are discussed. EM even of post mortem material contributes to knowledge of the structure of the parasite and of its life cycles.

Brain↗
PubMedDate not supplied

[Histopathologic and ultrastructural study of various amputation neuromas].

The results of a light and electron microscopy study of seven amputation neuromas are presented. The neuromas were removed during surgery for traumatic lesions of limbs. The histological study showed a complete disappearance of the nerve architecture at the neuroma level, where the fibres are collected in small bundles, enveloped in an abnormal perineural sheath, surrounded by an overgrowing connective tissue. In two cases a partial and incomplete reinnervation of the distal stump was found. The ultrastructural study shows abnormalities of the nervous fibers, both of the axon and of the relationships between the axonal part and the Schwann cell. The results of our data in man are compared to nerve regeneration patterns recently investigated in experimental models.

Adolescent↗