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Biomedical subjects

V Silani

Publications and source records attributed to V Silani.

At least 37 records · Page 2Linked to original sources
PubMed1999

A tentative interpretation of electromyographic regional differences in bulbar- and limb-onset ALS.

Electromyography (EMG) could be useful in defining regional motor neuron vulnerability in ALS. We performed EMG in 36 sporadic ALS patients (9 with bulbar-onset and 27 with limb-onset symptoms). Active denervation was more frequent in limb than in corresponding paraspinal muscles, in the thoracic paraspinal, and in the bulbo-cervical muscles in patients with bulbar-onset symptoms. These results are consistent with a regional motor neuron vulnerability along with a nerve length-dependent liability.

Adult↗
PubMed1999

Honesty and hope: announcement of diagnosis in ALS.

Informing patients and their families about a diagnosis such as amyotrophic lateral sclerosis (ALS) is a daunting task for any physician. The way the diagnosis is communicated will have a major impact on the physician-patient relationship and the attitude of the patient toward the disease and toward symptomatic treatment measures. Breaking the news can be truly defined as the starting point of palliative care in ALS. It is an ongoing information process which, by its nature, escapes narrow definitions or standardization attempts. Nevertheless, a number of techniques exist to facilitate the process and ease the burden for physicians, patients, and families. We believe that the terminal phase should be discussed at the latest when first respiratory symptoms appear, to prevent unwarranted fears of "choking to death."

Amyotrophic Lateral Sclerosis↗
PubMed1998

Immunomagnetic isolation of human developing motor neurons.

Human motor neuron (MN) isolation provides a critical tool to study neurophysiological properties and the effects of molecules of clinical relevance on isolated neurons. We developed an immunomagnetic separation technique based on specific MN antigen recognition for nerve growth factor receptor (p75-NGFR). We cultured an average of 250,000 cells from the anterior horns of a single cord (four specimens at postconception Weeks 6.0, 7.2, 8.0, and 8.3). At day 7 in vitro (DIV), choline acetyltransferase (ChAT) and/or p75-NGFR-expressing cells (MNs) represented 72 +/- 2% of the total growing cells. MNs survived for at least 4 weeks in biochemically defined medium. The immunomagnetic separation method has been demonstrated to be effective, reproducible, and quantitative for separation of MNs.

Cells, Cultured↗
PubMed1998

Nutritional management in amyotrophic lateral sclerosis: a worldwide perspective.

Although respiratory failure is the primary cause of death in patients with amyotrophic lateral sclerosis (ALS), the management of nutritional status is important to enhancing the quality of life and optimising the timing of interventive techniques. Progressively weakening muscles impair the patient's ability to eat, and nearly all patients with ALS develop severe dysphagia. If nutritional support is not provided, food and fluid consumption may be greatly restricted, leading to weight loss and malnutrition. This may be compounded by impaired respiratory functions, which place increased energy demands on the patient. This paper describes the nutritional needs of ALS patients from a worldwide and cross-cultural perspective. In particular, the differences between a paternalistic and a patient-centred approach to treatment are addressed. The need for further study into the nutritional status of ALS patients and the issue of parenteral and enteral nutritional therapy, particularly percutaneous endoscopic gastrostomy, are discussed.

Amyotrophic Lateral Sclerosis↗
PubMed1998

A placebo-controlled trial of insulin-like growth factor-I in amyotrophic lateral sclerosis. European ALS/IGF-I Study Group.

To test the safety and efficacy of recombinant human insulin-like growth factor-I (rhIGF-I) in ALS, 183 patients from eight European centers were randomized to receive double-blind placebo (n = 59) or rhIGF-I 0.1 mg/kg/day (n = 124) subcutaneously for 9 months. At study completion, the primary efficacy outcome measure (change in disease progression as assessed by the Appel ALS rating scale) showed no significant difference between treatment groups. RhIGF-I appeared to be safe and well-tolerated.

Adult↗
PubMed1997

Expression study of survival motor neuron gene in human fetal tissues.

In order to investigate the spinal muscular atrophy (SMA) disease processes, the expression of the survival motor neuron gene (SMN) has been analyzed in human fetal tissues using RT-PCR and in situ hybridization. These studies allowed the detection of SMN RNA in all the examined tissues, with no significant variation between different developmental stages. In particular, SMN mRNA was detected in spinal cord (dorsal and ventral portions), skeletal muscle, lung, heart, kidney, liver, and spleen. Moreover, RT-PCR studies demonstrated that the expression pattern of SMN isoforms was similar to that observed in adult tissues. The present data confirm a housekeeping role for the SMN protein and may have implications on the search for early therapeutic strategies.

Cyclic AMP Response Element-Binding Protein↗
PubMed1997

UFD1L, a developmentally expressed ubiquitination gene, is deleted in CATCH 22 syndrome.

The CATCH 22 acronym outlines the main clinical features of 22q11.2 deletions (cardiac defects, abnormal facies, thymic hypoplasia, cleft palate and hypocalcemia), usually found in DiGeorge (DGS) and velo-cardio-facial (VCFS) syndromes. Hemizygosity of this region may also be the cause of over 100 different clinical signs. The CATCH 22 locus maps within a 1.5 Mb region, which encompasses several genes. However, no single defect in 22q11.2 hemizygous patients can be ascribed to any gene so far isolated from the critical region of deletion. We have identified a gene in the CATCH 22 critical region, whose functional features and tissue-specific expression suggest a distinct role in embryogenesis. This gene, UFD1L, encodes the human homolog of the yeast ubiquitin fusion degradation 1 protein (UFD1p), involved in the degradation of ubiquitin fusion proteins. Cloning and characterization of the murine homolog (Ufd1l) showed it to be expressed during embryogenesis in the eyes and in the linear ear primordia. These data suggest that the proteolytic pathway that recognizes ubiquitin fusion proteins for degradation is conserved in vertebrates and that the UFD1L gene hemizygosity is the cause of some of the CATCH 22-associated developmental defects.

Adaptor Proteins, Vesicular Transport↗
PubMed1996

Deletion analysis of the simple tandem repeat loci physically linked to the spinal muscular atrophy locus.

Multicopy dinucleotide repeats have been characterized in the spinal muscular atrophy (SMA) region on chromosome 5q13, which reveal deletions in some SMA patients. 119 Italian and Spanish SMA families have been analysed using the C272 and C212 markers. Seventy percent of these families were informative. We found 9.4% de novo deletions in SMA I and 1.5% in SMA II families. A single inherited deletion segregating in a Spanish pedigree was detected in three affected brothers. A SMA II patient showed deletion only of C272. The data presented in this study are relevant to the molecular diagnosis of SMA families in Italy and Spain and provide additional insights toward the understanding of the molecular pathology of SMA.

Alleles↗
PubMed1996

Clinical and pathological features in hydrocarbon-induced parkinsonism.

A neuropathological examination was performed on a patient with parkinsonism induced by prolonged exposure to a mixture of aliphatic hydrocarbons, mainly n-hexane and halogenated compounds. The patient developed a rapid-course disease that progressed even after withdrawal from the toxic exposure. Pathological examination and immunohistochemical analysis of the brain revealed severe and widespread dopaminergic neuronal loss, associated with severe gliosis, in the substantia nigra, and almost complete loss of tyrosine hydroxylase immunostaining in the striatum. No Lewy bodies were detected. Neuronal loss was also observed in the periaqueductal gray matter, locus ceruleus, and pedunculopontine nucleus. These changes, combined with the moderate anemia due to marrow suppression, and the mild axonal neuropathy observed in vivo, are suggestive of a hydrocarbon toxic insult.

Female↗
PubMed1996

Ras p21 protein promotes survival and differentiation of human embryonic neural crest-derived cells.

We have previously shown that the oncogene product p21 Ras is essential for the survival and neurite outgrowth-promoting activity of nerve growth factor on cultured chick embryonic sensory, but not sympathetic neurons. In order to extend our observations to the human system and to non-neuronal cells, we introduced the oncogenic form of p21 Ras into the cytoplasm of three different types of cultured human embryonic neural crest derivatives (8th-11th gestational week): dorsal root ganglion neurons, sympathetic neurons, and adrenal chromaffin cells. These cells are dependent on nerve growth factor for survival and/or fibre outgrowth in vitro. In dorsal root ganglion neurons, p21 Ras promoted survival and fibre outgrowth which was quantitatively and qualitatively comparable to the nerve growth factor effect (84% vs. 95%, control 18%). Sympathetic neurons showed a similar effect, albeit with a higher background survival (91% vs. 93%, control 58%). On chromaffin cells, which respond to nerve growth factor with pronounced fibre outgrowth in culture, the effect of p21 Ras was again comparable to that of nerve growth factor (35% vs. 30%, control 5%). The survival and fibre outgrowth-promoting effects of p21 Ras on human embryonic dorsal root ganglion neurons, sympathetic neurons and chromaffin cells suggest an involvement of p21 Ras in the intracellular signal transduction of nerve growth factor in human neural crest-derived cell populations.

Cell Differentiation↗
PubMed1996

cDNA characterization and chromosomal mapping of two human homologues of the Drosophila dishevelled polarity gene.

The Drosophila dishevelled gene (dsh) encodes a secreted glycoprotein, which regulates cell proliferation, acting as a transducer molecule for developmental processes, including segmentation and neuroblast specification. We have isolated and characterized cDNA clones from two different human dsh-homologous genes, designated as DVL-1 and DVL-3. DVL-1 and DVL-3 putative protein products show 64% amino acid identity. The DVL-1 product is 50% identical to dsh and 92% to a murine dsh homologue (Dvl-1). Both human DVL genes are widely expressed in fetal and adult tissues, including brain, lung, kidney, skeletal muscle and heart. DVL-1 locus maps to chromosome 1p36 and DVL-3 to chromosome 3q27. DVL-1 locus on chromosome 1 corresponds to the murine syntenic region where Dvl-1 is located. DVL-1 and DVL-3 are members of a human dsh-like gene family, which is probably involved in human development. Although the precise role of these genes in embryogenesis is only conjectural at present, the structural and evolutionary characteristics suggest that mutations at their loci may be involved in neural and heart developmental defects.

Adaptor Proteins, Signal Transducing↗
PubMed1996

Human homologue sequences to the Drosophila dishevelled segment-polarity gene are deleted in the DiGeorge syndrome.

DiGeorge syndrome (DGS) is a developmental defect of some of the neural crest derivatives. Most DGS patients show haploinsufficiency due to interstitial deletions of the proximal long arm of chromosome 22. Deletions of 22q11 have also been reported with patients with the velocardio-facial syndrome and familial conotruncal heart defects. It has been suggested that the wide phenotype spectrum associated with 22q11 monosomy is a consequence of contiguous-gene deletions. We report the isolation of human cDNAs homologous to the Drosophila dishevelled (dsh) segment-polarity gene. Sequences homologous to the 3' UTR of these transcripts (DVL-22) were positioned within the DGS critical region and were found to be deleted in DGS patients. Human DVL mRNAs are expressed in several fetal and adult tissues, including the thymus and, at high levels, the heart. Two transcripts, 3.2 and 5kb, were detected, in northern blot analysis, with different expression patterns in the surveyed tissues when different cDNAs were used. The isolated cDNAs exhibit high amino acid homology with the mouse and Xenopus Dvl-1 gene, the only other vertebrate dsh homologues so far isolated. The pivotal role of dsh in fly development suggests an analogous key function in vertebrate embryogenesis of its homologue genes. Since DGS may be due to perturbation of differentiation mechanisms at decisive embryological stages, a Dsh-like gene in the small-region overlap (SRO) might be a candidate for the pathogenesis of this disorder.

Adaptor Proteins, Signal Transducing↗
PubMed1995

Identification of multiple transcribed sequences from the spinal muscular atrophy region of human chromosome 5.

We report the isolation and characterization of novel expressed sequences from the spinal muscular atrophy (SMA) region on human chromosome 5q13. Based on the sequence homology studies these cDNAs were grouped in four classes, one of which shows extensive homologies with the beta-glucuronidase (BG) gene, differing in exon arrangement. The other cDNAs do not show any strong homology with known DNA sequences.

Base Sequence↗
PubMed1995

Postzygotic instability of the myotonic dystrophy p[AGC] in repeat supported by larger expansions in muscle and reduced amplifications in sperm.

We have analysed the [AGC] expansion in leucocytes, muscle and sperm from 17 individuals affected by myotonic dystrophy (DM). Skeletal muscle showed a larger repeat number than leucocytes in the same patient. A similar degree of expansion was detected in differently affected muscles of a single patient. The germline mutation (< or = 350 repeats) was expanded in somatic cells of the progeny in all patients examined. Our results provide evidence of an early postzygotic instability of the [AGC] repeat in DM.

Adolescent↗
PubMed1995

Molecules with neurotrophic effects on the human developing mesencephalic dopaminergic neurons.

Parkinson's disease (PD) is characterized by the degeneration of the mesencephalic dopaminergic (mesDA) neurons innervating the striatum. Neurotrophic factor(s) that prevents the degeneration and increases the functional activity of the remaining mesDA neurons are of substantial clinical interest. The origin and development of mesDA neurons were characterized in the human mesencephalon from 5.0 to 12 Postconception (PC) weeks. Tyrosine Hydroxylase (TH) immunoreactive cells were first demonstrated at 5.5 PC weeks next to the ventricular zone. In primary culture, TH immunoreactive neurons represent 3 to 5% of the total cells at days 7 in vitro and basic Fibroblast growth factor (bFGF) was demonstrated to induce a significant increase of both TH immunoreactive cell number and TH enzymatic activity. This effect was mediated by proliferating glial fibrillary acidic protein immunoreactive cells. Nerve growth factor treatment did not have any appreciable effect. The effect of bFGF on TH positive cells described in this human bioassay is only a preliminary evidence that, if confirmed by experiments in vivo, may provide a starting rationale for investigating alternative strategies in the treatment of PD.

Cell Division↗
PubMed1994

NGF-response of EGF-dependent progenitor cells obtained from human sympathetic ganglia.

Signalling molecules are thought to play a significant role in determining the fate of neural crest progenitor cells. The human sympathetic chain was identified at 6.5, 7.5, 8.2, 10.2 and 11.4 postconception (PC) weeks demonstrating low affinity nerve growth factor (NGF) receptors, and was processed for tissue culture. In the presence of epidermal growth factor (EGF), floating spheres of proliferating progenitor cells were developed in vitro. In the absence of EGF progenitor cells differentiated into tyrosine hydroxylase (TH)-immunoreactive neuronal and TH-negative flat cells. NGF treatment significantly increased neurite outgrowth and survival of TH-immunoreactive cells. The multipotent cells we isolated differ from previously reported sympathoadrenal progenitors in that they give rise to TH immunoreactive neurones precociously sensitive to NGF.

Cell Survival↗
PubMed1994

Development of dopaminergic neurons in the human mesencephalon and in vitro effects of basic fibroblast growth factor treatment.

The origin and development of the mesencephalic dopaminergic (mesDA) neurons within the substantia nigra were characterized in human embryos from Postconception (PC) Week 5.0 to 12.0. Tyrosine hydroxylase (TH) immunoreactive cells were first demonstrated in the ventral mesencephalon at PC Week 5.5 next to the ventricular zone. Cell migration and neurite outgrowth of TH-positive neurons were timed. Early expression of ganglioside GM1 was demonstrated in developing neurons. Glial fibrillary acidic protein (GFAP) was first observed at PC Week 10.0 instead, after the dopaminergic neurotransmitter phenotype expression. In vitro complementary information was obtained: TH-positive cells represented about 3% of the total cell population after a week in culture, based upon accurate anatomical dissection. They tended to form microaggregates and to grow in close contact with glial cells. MesDA neuronal expression of TH activity was measured by a biochemical microassay. TH-positive cells responded to basic fibroblast growth factor (bFGF) both with increased TH activity and neuronal survival. bFGF effects were mediated by the proliferative action on glial cells. Astroglial GFAP-positive cells express nerve growth factor-low-affinity receptor in culture. Information on in vitro and in vivo sequences of mesDA neuronal development and their response to identified neurotrophic molecules may be invaluable for selection of the most appropriate tissue donor age for brain grafting and development of alternative treatment strategies for Parkinson's disease.

Cell Movement↗