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Biomedical subjects

A Vital

Publications and source records attributed to A Vital.

At least 37 records · Page 2Linked to original sources
PubMed2001

Immunohistochemical assessment of human herpesvirus 8 infection in primary central nervous system large B cell lymphomas.

BACKGROUND/AIMS: Primary central nervous system large B cell lymphomas (PCNSLs) are frequently associated with Epstein-Barr virus (EBV) in patients with AIDS and less frequently in those without AIDS. Human herpesvirus 8 (HHV-8) has been detected in these tumours by the polymerase chain reaction (PCR) at low copy number, suggesting its presence in a cell compartment other than the malignant one. The aim of this study was to use immunohistochemistry to assess HHV-8 infection in a series of PCNSLs from patients with and without AIDS. METHODS: The antibody LN53, which reacts with the latent nuclear antigen 1 (LNA1) of HHV-8, was used on tissue sections from 35 patients (17 with and 18 without AIDS) with PCNSL. In addition, DNA was available for PCR (open reading frame 26 (ORF 26), ORF 72, ORF 75) in three patients (two without AIDS, one with AIDS). RESULTS: None of the 35 cases contained either DNA sequences or LNA1 positive cells. CONCLUSIONS: These results confirm the lack of HHV-8 infection in tumour cells of PCNSL. In addition, HHV-8 infected bystander cells do not express LNA1 latent protein in this setting.

Animals↗
PubMed2001

Mild recurrent neuropathy in CMT1B with a novel nonsense mutation in the extracellular domain of the MPZ gene.

Clinical, electrophysiological, and neuropathological features are reported associated with a novel heterozygote point mutation in the extracellular domain of the MPZ gene, where a transversion at codon 71 in exon 3 leads to a codon stop: Glu71stop (ie GAA-->TAA). A 36 year old woman developed a mild recurrent neuropathy after intensive manual work. The motor nerve conduction velocities were slow without conduction blocks and the nerve biopsy showed signs of demyelination-remyelination, axonal loss, and regular uncompacted myelin lamellae. She inherited the mutation from her father who displayed the same mutation with a normal phenotype. This nonsense mutation may cause a dosage difference of normal P0, and is probably underrepresented in the current mutation data bases. This report further extends the phenotype of MPZ mutations and also emphasises that mild phenotype of CMT1B may be more frequent than has been appreciated.

Adult↗
PubMed2000

Expression of Trk isoforms in brain regions and in the striatum of patients with Alzheimer's disease.

The TrkAII tyrosine kinase receptor differs from the TrkAI isoform by an insertion of six amino acids in the extracellular domain. We used RT-PCR to determine their respective distribution in rat and human brain. Only trkAII transcripts were detected in 12 rat brain regions, while both trkAI and trkAII transcripts were detected in the cerebellum and pituitary gland. In human, both trkAI and trkAII transcripts were detected in the frontal, temporal, and occipital cortex and thalamus, while only trkAI transcripts were detected in the hippocampus and cerebellum. In the caudate and putamen, trkAII transcripts were exclusively detected. Thereafter, we studied the expression of TrkA isoforms in the striatum of five patients with Alzheimer's disease (AD), four patients with non-AD dementia, seven patients with Parkinson's disease, and six paired nondemented elderly control individuals. In controls and non-AD patients, a constant expression of trkAII transcripts was detected within all striatum parts. In AD patients, a heterogeneous decrease in trkAII expression was observed in the caudate, putamen, and ventral striatum, resulting either in a drop of trkAII transcript levels or in a weak coamplification of trkAII and trkAI transcripts. The alteration of TrkAII gene expression paralleled those of choline acetyltransferase. Together with previous data, this suggests that the alteration of trk gene expression could contribute to a decrease in NGF binding sites and its protective effects on cholinergic neurons of AD patients.

Adult↗
PubMed2000

Chronic inflammatory demyelinating polyneuropathy associated with dysglobulinemia: a peripheral nerve biopsy study in 18 cases.

The possible occurrence of chronic inflammatory demyelinating polyneuropathy (CIDP) in association with an identified dysglobulinemic status is recognized and a causal relationship between the two has been suggested. We had the opportunity to study 18 patients presenting with CIDP and dysglobulinemia. This was an IgG monoclonal gammopathy (IgG MG) in 8 cases, an IgM monoclonal gammopathy (IgM MG) in 8, an IgG-IgM biclonal gammopathy in 1 case and an IgM monoclonal cryoglobulinemia in another. A peripheral nerve biopsy specimen was available for all patients and the morphological findings in these specimens in the cases of CIDP with IgG MG or cryoglobulin did not differ from those without, whereas characteristic features were observed in the cases of CIDP with IgM MG and anti-myelin associated glycoprotein activity.

Aged↗
PubMed2000

Inexcitability of nerves in a fulminant case of Guillain-Barré syndrome.

A 45-year-old woman presented with a recent sensorimotor deficiency in all 4 limbs, and the next day she was totally paralyzed. A slight motor improvement began on day 27. The cerebrospinal fluid had normal cellularity, but the protein varied from 90 mg/dL on the first day to 800 mg/dL on day 15, and then 290 mg/dL on day 33. Electrophysiologic studies performed on days 15 and 23 revealed a universal peripheral nerve inexcitability. A superficial peroneal nerve biopsy was performed on day 23. Nine fascicles were examined on semi-thin sections and myelinated fiber damage varied greatly from one fascicle to another. At ultrastructural examination, certain axons were severely damaged, but the others were quite well preserved and were naked or wrapped in a myelin sheath presenting a multivesicular degeneration. A few fibers had a better-preserved myelin sheath that was sometimes dissociated by elongated processes from an invading histiocyte. Six cases of fulminant Guillain-Barré syndrome with inexcitability of nerves and ultrastructural examination of nerve fragments have been reported. Electrophysiologic study is often ambiguous and cannot determine the precise origin of such an axonal degeneration. Therefore, ultrastructural analysis of a nerve biopsy is mandatory in this setting.

Axons↗
PubMed2000

Chronic inflammatory demyelinating polyneuropathy caused by HIV infection in a patient with asymptomatic CMT 1A.

It is well known that patients with Charcot-Marie-Tooth (CMT) disease are liable to present with episodes of cortisone-responsive demyelination, and a superimposed inflammatory component has been suggested. We report a patient who presented with a chronic inflammatory demyelinating polyneuropathy due to a recent HIV infection, which revealed a previously asymptomatic CMT 1A disease documented by identification of the characteristic duplication on the p11.2 region of chromosome 17. The inflammatory process was characterized by pathologic findings on a superficial peroneal nerve biopsy, and the patient improved significantly after corticotherapy. This report gives support to the hypothesis of a genetic susceptibility to inflammatory demyelinating processes in certain CMT kindreds.

Adult↗
PubMed2000

Guillain-Barré syndrome occurring in two women after ketoacidosic comatose state disclosing an insulin-dependent diabetes mellitus.

We report two women who presented with a Guillain-Barré syndrome just after a ketoacidosic comatose state disclosing an insulin-dependent diabetes mellitus. One had characteristic clinical signs and the other had major motor involvement. At neurophysiologic investigations, one had typical demyelinating neuropathy whereas the second had mainly axonal degeneration. At ultrastructural examination of a peripheral nerve biopsy, features of macrophage-associated demyelination were present in both nerve specimens, thus confirming the diagnosis of acute inflammatory demyelinating polyneuropathy, i.e., Guillain-Barré syndrome. Prominent axonal involvement was also present in the motor nerves of the second patient. Insulin therapy had to be permanently continued and these two cases are quite different from the transient diabetes sometimes observed in certain cases of Guillain-Barré syndrome. Both the latter and insulin-dependent diabetes mellitus probably have auto-immune mechanisms. It is likely that in our two patients both auto-immune diseases were triggered by a common event. Such cases of Guillain-Barré syndrome have to be distinguished from other acute diabetic neuropathies.

Adult↗
PubMed2000

Hepatitis C virus infection with and without cryoglobulinemia as a case of Churg-Strauss syndrome.

Chronic hepatitis C virus (HCV) infection may be associated with numerous immune disorders, with vasculitis including polyarteritis nodosa, or with both. Cryoglobulinemia, which is often present, can also be expressed by vasculitis. We describe 2 cases of Churg-Strauss syndrome (CSS) in patients with HCV infection. We found no previous case of CSS accompanying HCV infection in the literature. The current patients were women aged 40 and 66 years. In both cases, a clinical and laboratory pattern suggesting CSS was found before the HCV infection was discovered. One patient had cryoglobulinemia. One patient was successfully treated with interferon (IFN). The other was treated for 18 months with IFN and corticosteroids. Second-line therapy consisting of IFN with ribavirin was successful. The emergence of HCV infection may have led to an induced form of CSS. The relationship among HCV, cryoglobulinemia, and CSS is not clear, but may be similar to that existing between polyarteritis nodosa and hepatitis B virus. These observations suggest that IFN-alpha therapy may be effective against CSS in HCV infected patients with or without cryoglobulinemia.

Adrenal Cortex Hormones↗
PubMed2000

Squamous cell carcinoma developing in an intracranial prepontine epidermoid cyst.

Intracranial epidermoid cysts represent around 0,2 to 1 % of all intracranial tumours. Rare malignant transformation of these benign lesions may occur. A 66-year-old man presented with a state of confusion. MRI demonstrated a heterogeneous signal in front of the pons and ventricular dilatation. Cerebrospinal fluid examinations disclosed inflammatory cells. The patient died six months after his first admission to hospital. At autopsy, a firm greyish tumour (3 cm-long and 1 cm-thick) was present in front of the brain stem encasing the basilar artery. Microscopic examination revealed a well-differentiated epidermoid carcinoma arising from a cystic lesion whose wall was lined by a squamous epithelium with a benign appearance. The walls of all the ventricles were lined by carcinomatous cells. There was no leptomeningeal metastasis. Twenty three other cases of such squamous cell carcinoma have been reported and most of them had died within a few months.

Basilar Artery↗
PubMed2000

Histopathological variants of central neurocytoma: Report of 10 cases.

Central neurocytoma is a rare neuronal tumor affecting young adults and usually located in the lateral ventricles. Post-operative prognosis is generally good. Histologically, central neurocytoma is composed of isomorphous small round or ovoid cells alternating with irregularly shaped patches of fibrillary matrix similar to the neuropile. In a series of 10 cases, two central neurocytomas were histologically "atypical" at first examination. One was intra-ventricular, and the second had an intra-parenchymatous juxta-ventricular location. Both were highly cellular with mitotic activity, and tumor necrosis was seen in one. Neuronal differentiation was assessed by synaptophysin immunoreactivity in all 10 cases and by ultrastructural examination in four, including the two "atypical" forms. Neuronal differentiation was less marked in these "atypical" forms, one also presenting focal GFAP immunoreactivity. The proliferative potential was determined by MIB-1 labeling index and compared with clinical outcome. The eight classical central neurocytomas had a MIB-1 labeling index < 2.3%, whereas the two "atypical" forms had a MIB-1 labeling index > 5.2% and both recurred. We think that there is a spectrum of small-cell neuronal tumors. The two extremes could be the central neurocytoma and the primary cerebral neuroblastoma, while the intermediate forms might be qualified as "atypical neurocytoma". In our series, the histological and immunohistochemical criteria of biological aggressiveness appeared to be high mitotic activity, tumor necrosis, loss of neuronal differentiation and high MIB-1 labelling index.

Adult↗
PubMed1999

Anti-MAG IgM penetration into myelinated fibers correlates with the extent of myelin widening.

The purpose of this study was to evaluate the relationship between immunoglobulin M (IgM) antibodies penetration into myelinated peripheral nerve fibers and the widening of the peripheral myelin sheaths in anti-myelin-associated glycoprotein (anti-MAG) demyelinating IgM monoclonal polyneuropathy. Demyelinating polyneuropathy with monoclonal IgM is often associated with anti-MAG autoantibodies, which are thought to initiate the disease with IgM deposits usually present on the myelin sheaths. We analyzed nerve biopsies from 12 patients with an anti-MAG demyelinating neuropathy by confocal and electron microscopy. The total number of nerve fibers and the proportion of IgM-associated fibers were quantified after immunohistochemical staining. The affinities of IgM were examined by analyzing the binding pattern of serum IgM on normal peripheral nerve sections. Ultrastructural examinations of the biopsies showed a good correlation between in situ widened myelin sheaths and the IgM penetration level into myelinated fibers. The terminal complement complex appears not be involved in the penetration of IgM into the myelinated fibers. Our findings suggest a causative role of the IgM anti-MAG antibodies in the ultrastructural modifications of the myelin sheaths. The basement membrane and myelin components appear to be the major targets of the IgM monoclonal antibodies. However, the pathogenic mechanism whereby IgM antibodies reach their targets and induce nerve damage are still unclear.

Fluorescent Antibody Technique↗
PubMed1999

Asymmetrical polyneuropathy with a stepwise progressive course and well-demarcated areas of demyelination.

A female patient was 12 years old when she presented with hemiatrophy and muscle weakness on the right side of her body. Then a stepwise worsening occurred, and at 19 years of age sensory symptoms were also noticed, as well as a mild involvement of the left part of her body. The cerebrospinal fluid (CSF) protein level was elevated without cells. The main electrophysiological abnormality was a marked temporal dispersion of the compound muscle action potentials (CMAPs). Motor nerve conduction velocities were moderately reduced. A superficial peroneal nerve biopsy revealed well-demarcated areas of demyelination with prominent Schwann cell hyperplasia. Neither deletion nor duplication of the PMP22 gene nor mutation of the P0 or connexin 32 genes was found by molecular genetic investigations. Immunotherapy was administered, and over the next 6 years the symptomatology fluctuated. This unusual disorder seems to be a variant of chronic acquired demyelinating polyneuropathy and may be immunologically mediated.

Child↗
PubMed1999

Chester-Erdheim disease: a neoplastic disorder.

Chester-Erdheim disease is a rare non-langerhans cell histiocytosis characterized by a xanthomatous infiltration of foamy macrophages. The cause and pathogenesis remain unclear. The aim of the present study was to determine whether Chester-Erdheim disease is a polyclonal reactive disease or a clonal neoplastic disorder. The clonal status of samples obtained from five patients with Chester-Erdheim disease was studied. DNA was extracted from fixed and paraffin-embedded sections after microdissection and clonal status was studied using the Xchromosome inactivation pattern of the human androgen receptor gene (HUMARA assay). One patient was homozygous for the HUMARA gene and noninformative. Three other cases were monoclonal. One was polyclonal, and this case showed a dense reactive infiltrate in association with spumous macrophages. This study suggests strongly that Chester-Erdheim disease is a monoclonal lesion consistent with neoplastic disorder. Thus, Chester-Erdheim disease may be considered as the "macrophage" counterpart of Langerhan's cell histiocytosis in the histiocytosis spectrum. Further studies are needed to establish the origin of this clonal proliferation.

Adult↗
PubMed1999

Peripheral myelin modification in CMT1B correlates with MPZ gene mutations.

Morphological modifications were investigated in the peripheral nerve of three unrelated patients with CMT1B. In two patients, molecular genetic analysis showed an Arg98His mutation in the extracellular domain of MPZ, associated with irregularly uncompacted lamellae. This observation confirms previous studies of a well-defined correlation between mutations and morphological phenotypes. In the third patient, a de novo Asp109Asn mutation was associated with abnormally thick myelin sheaths. This adds to the known list of MPZ gene mutations associated with this morphological phenotype.

Adult↗
PubMed1999

[Intramuscular myxoma. A case of myxoma of the spinal erector muscle].

A case of intramuscular myxoma, extended in the lumbar erector spinae muscles, is reported. This soft tissue tumor is rare, about one hundred observations are indexed in the literature. The clinical findings are nonspecific, magnetic resonance imaging reveals few characteristics, and finally a histological examination is required, after surgical removal, to pinpoint the diagnosis. Recurrence is uncommon, but a systematic follow-up is necessary.

Female↗