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Biomedical subjects

E Parati

Publications and source records attributed to E Parati.

At least 19 recordsLinked to original sources
PubMed2006

Pravastatin in vivo reduces mononuclear cell migration through endothelial monolayers.

The objective was to evaluate pravastatin modulation on peripheral blood mononuclear cell (PBMC) migration across endothelial monolayers. Eleven hypercholesterolaemic patients were treated with pravastatin 20 mg/day. At baseline (T0), after 40 days (T40) and after 6 months (T 6 months) of treatment total serum cholesterol, low-density lipoprotein (LDL), high-density lipoprotein, triglycerides, C-reactive protein, as well as tumour necrosis factor-alpha (TNF-alpha) and metalloproteinases-9 plasma levels were evaluated. At the same time points the effect of pravastatin on migration of PBMCs through a monolayer of murine brain endothelial cells was studied both in basal conditions and after endothelial stimulation with recombinant mouse TNF-alpha 10 ng/ml for 24 h. Seven volunteers were used as healthy controls. Significant decreases in total cholesterol, LDL and triglycerides as well as inhibition of transmigration were observed. PBMCs transmigration in patients prior to pravastatin therapy was higher than in healthy controls. These results suggest that pravastatin could be of benefit in a spectrum of diseases characterised by extravasation of PBMCs into the central nervous system.

Aged↗
PubMed2005

Human microvascular endothelial cells from different fetal organs demonstrate organ-specific CAM expression.

In this work, we isolated and produced long-term cultures of human fetal endothelial cells (fECs) deriving from different organs of the same 12-week-old embryos. Highly pure endothelium cultures were obtained from specimens of brain, heart, lung, liver, aorta and kidney by using magnetic microspheres coated with CD31 or CD34 specific endothelial antibodies. The endothelial nature of these cells was confirmed by the presence of von Willebrand Factor (vWf), Flk-1/VEGFR2 and CD31. The fECs cultures showed organ-specific differences as regards to the morphological appearance, the growth rate and the expression of cellular adhesion molecules (CAMs) before or after stimulation by the inflammatory cytokines IL-1beta and TNF-alpha. For instance, TNF-alpha showed a specific effect on fetal heart ECs by stimulating E-selectin expression. Our findings indicate that fECs may represent an innovative tool to study differences among ECs of different vascular districts of the same individual, thus increasing the possibility to compare many pathological aspects of human adult and fetal microvasculature.

Antigens, Surface↗
PubMed2005

Endogenous activation of metabotropic glutamate receptors supports the proliferation and survival of neural progenitor cells.

The use of neural progenitor cells (NPCs) is limited by the incomplete knowledge of the extracellular signals regulating their proliferation and survival. We report that cultured mouse NPCs express functional mGlu3 and mGlu5 metabotropic glutamate receptors. Pharmacological blockade of both receptors reduced NPC proliferation and survival, whereas activation of mGlu5 receptors substantially enhanced cell proliferation. Adult mice lacking mGlu5 receptors or treated with mGlu5 or mGlu3 receptor antagonists showed a dramatic reduction in the number of dividing neuroprogenitors present in the subventricular zone and in the dentate gyrus of the hippocampus. These data disclose a novel function of mGlu receptors and offer new potential strategies for the optimization of cell replacement therapy in neurodegenerative disorders.

Animals↗
PubMed2004

Immunotherapy with bovine aortic endothelial cells in subcutaneous and intracerebral glioma models in rats: effects on survival time, tumor growth, and tumor neovascularization.

High-grade gliomas are aggressive tumors of the central nervous system characterized by endothelial cell proliferation and a high degree of vascularity. Conventional antitumoral treatments (i.e., surgery, radiotherapy, and chemotherapy) do not achieve satisfactory results (median survival in glioblastoma 12-18 months). It has been suggested that immunotherapy with xenogenic endothelial cells could slow tumor growth rate in a number of tumors in a murine model, but the study did not include gliomas. In experiments performed in our laboratory, vaccination with proliferating bovine aortic endothelium increased survival time in Fischer rats inoculated intracerebrally with 9L. Immunotherapy was also able to reduce the growth of subcutaneously injected 9L gliosarcoma cells in Fischer rats and to decrease microvessel density within the tumors, in the absence of major organ toxicity. Immunoglobulins (Ig) in the sera from vaccinated rats stained bovine aortic endothelium as well as human umbilical vein endothelium in active proliferation. Moreover, immune sera from immunized rats stained microvessels of human malignant glioma specimens and vessels of intracerebrally implanted tumors. Two proteins of MW of 11 and 19 kDa were identified by Western blot as targets of Ig elicited by vaccination. A possible future development is to select peptides/proteins suitable for vaccination in humans, avoiding the biohazards connected with xenogenic whole-cell vaccination.

Animals↗
PubMed2001

Human vasculogenesis ex vivo: embryonal aorta as a tool for isolation of endothelial cell progenitors.

SUMMARY: Vasculogenesis, the de novo formation of new blood vessels from undifferentiated precursor cells or angioblasts, has been studied with experimental in vivo and ex vivo animal models, but its mechanism is poorly understood, particularly in humans. We used the aortic ring assay to investigate the angioforming capacity of aortic explants from 11- to 12-week-old human embryos. After being embedded in collagen gels, the aorta rings produced branching capillary-like structures formed by mesenchymal spindle cells that lined a capillary-like lumen and expressed markers of endothelial differentiation (CD31, CD34, von Willebrand factor [vWF], and fms-like tyrosine kinase-1 [Flk-1]/vascular endothelial growth factor receptor 2 [VEGFR2]). The cell linings of these structures showed ultrastructural evidence of endothelial differentiation. The neovascular proliferation occurred primarily in the outer aspects of aortic rings, thus suggesting that the new vessels mainly arose from immature endothelial precursor cells localized in the outer layer of the aortic stroma, ie, a process of vasculogenesis rather than angiogenesis. The undifferentiated mesenchymal cells (CD34+/CD31-), isolated and cultured on collagen-fibronectin, differentiated into endothelial cells expressing CD31 and vWF. Furthermore, the CD34+/CD31+ cells were capable of forming a network of capillary-like structures when cultured on Matrigel. This is the first reported study showing the ex vivo formation of human microvessels by vasculogenesis. Our findings indicate that the human embryonic aorta is a rich source of CD34+/CD31- endothelial progenitor cells (angioblasts), and this information may prove valuable in studies of vascular regeneration and tissue bioengineering.

Antigens, CD34↗
PubMed1993

Decreased cholesterol biosynthesis in fibroblasts from patients with Parkinson disease.

The underlying cause of cellular degeneration in the substantia nigra of patients with Parkinson disease has not been clearly established. With the objective of investigating whether metabolic abnormalities would be detected in peripheral non-neuronal cells, we began assessing key metabolic parameters in skin fibroblasts of these patients. The present report focuses on the finding of a remarkably reduced cholesterol biosynthetic capability of fibroblasts from patients with Parkinson disease. 14C-Acetate incorporation into cholesterol of these fibroblasts was 27.8 +/- 9.4% that observed in normal fibroblasts, and the reduced cholesterol synthesis was confirmed by measuring the activity of the rate-limiting enzyme HMGCoA reductase which averaged 6.64 +/- 2.50 nmol/h/mg protein in the patient's fibroblasts compared to 14.70 +/- 0.69 nmol/h/mg protein in the control fibroblasts. Cholesterol esterifying activity, as cholesteryl oleate formed from 14C-oleate, of the fibroblasts from Parkinson patients, was reduced by an average 43%. Two hypotheses are put forward to link these findings with the current experimental evidences for both increased lipid peroxidation and defective mitochondrial respiratory chain complex I activity in a number of cell types from Parkinson patients. Considering that decreased cholesterol biosynthesis has been detected in all the Parkinson cell lines thus far investigated, it is suggested that this may be a hallmark of the disease.

Adult↗
PubMed1993

Physical effort-induced changes in immune parameters.

Physical stress induces changes in immune system parameters; these changes depend on effort schedule and are influenced by customary training. The mechanisms whereby they take place are not fully elucidated: sympathetic activation-mediated mobilization of cells of lymphoid organs, including the spleen, has been suggested. We studied exercise-induced changes (20' of cycloergometer test conducted up to 80% of maximal expected heart rate) in white blood cells (WBC), lymphocyte subsets, plasma catecholamine and cortisol levels in three groups of subjects: swimmers, untrained controls and splenectomized individuals. Physical exercise induced increase of WBC and significant changes in the percentage of most investigated lymphocyte subsets (NK, CD3+, CD4+, CD8+ and CD4/CD8 ratio), except for DR+ cells. No changes occurred in the percentage of CD14+ cells. Norepinephrine (NE) levels increased after effort, while epinephrine (E) and cortisol levels were unchanged. Splenectomized patients displayed similar effort-induced changes in investigated parameters as controls and swimmers. The results support the interactions between physical work and immune response and minimize the role of the spleen in this context.

Adult↗
PubMed1992

The chemical characterization of melanin contained in substantia nigra of human brain.

The pigment of substantia nigra human brain has been extracted by a mild procedure consisting of washes with phosphate buffer, methanol and incubation with SDS-proteinase. Pyrolysis gas chromatography mass spectrometry, infrared spectrometry, termogravimetric analysis and elemental analysis were the techniques used for the chemical characterization. An indole moiety bound to a sulfur containing amino acid and to palmitic acid were the main aspects found in the structure. The presence of a 7% inorganic component was observed. This probably contains Fe, Cu, Zn and Cr which are also relevant, for the formation and the role of melanin in substantia nigra neurons. The fatty acid moiety is chemically bound to the indole structure as it was not eliminated by repeated methanol washing. The same situation occurs for the sulfur containing group. Considering these data and the most abundant molecules present in substantia nigra the precursor of neuromelanin seems to be a cysteinyl-catechol, to which is then bound a palmityl group.

Adult↗
PubMed1990

Pupillometry and radioreceptor binding. Semeiologic suggestions in the evaluation of the treatment with anticholinergic drugs.

In this study, a dynamic TV pupillometric system has been used to record the effects of the anticholinergic drug biperidene (Akineton) on pupil responsiveness to various types of stimuli. Plasma levels of the drug were evaluated by means of the radioreceptor binding technique at the same times of pupillometric monitoring. An excellent correlation was found between the effects of biperidene on pupil diameter after light and dark adaptation, light reflex and near vision reaction and the plasma levels of the drug. Radioreceptor binding and dynamic TV pupillometry represent useful tools to evaluate the possible alterations induced by drug therapy on the cholinergic system in man.

Adult↗
PubMed1986

Manganese neurotoxicity: effects of L-DOPA and pargyline treatments.

Single, monolateral injection into rat substantia nigra of manganese chloride produced within two weeks from its administration a loss of dopamine in the striatum ipsilateral to the injected side. The effect was dose-dependent and was not extended to serotoninergic terminals present in this brain area, whose content in serotonin and 5-hydroxyindoleacetic acid was not affected. When L-DOPA + carbidopa or pargyline were given to these animals the decrease of striatal dopamine was more marked. Moreover, rats treated two weeks before with a dose of manganese chloride that produced a 70-80% drop in striatal dopamine concentrations, rotated ipsilaterally to the dopamine-depleted striatum when injected with apomorphine, suggesting that in these animals the stimulatory effects of apomorphine were more relevant in striatum where presynaptic dopaminergic neurons were not affected by manganese chloride. These data indicate that the alterations of dopaminergic postsynaptic receptors may be different in parkinsonian and in manganese-intoxicated patients and that current therapy used for Parkinson's disease could be a hazard in treating manganese poisoning.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1986

Differential effect of repeated treatment with L-dopa on dopamine-D1 or -D2 receptors.

Unilateral degeneration of the nigro-striatal dopaminergic pathway with 6-hydroxydopamine induced contralateral rotations to apomorphine injection, increased [3H]-spiroperidol binding and enhanced sensitivity of adenylate cyclase to dopamine stimulation in lesioned striata. Prolonged L-DOPA administration counteracted the increased density of [3H]-spiroperidol binding sites but further enhanced the hypersensitivity of adenylate cyclase to dopamine. Also apomorphine-induced contralateral rotations were potentiated. This effect was antagonized by SCH-23390. These results suggest that dopaminergic D1 and D2 receptors are differently affected by prolonged L-DOPA treatment.

Adenylyl Cyclases↗
PubMed1986

Dopamine receptor changes in response to prolonged treatment with L-dopa.

Unilateral lesions of the nigro-striatal dopamine (DA) pathway induced contralateral rotations to apomorphine, increased (3H)-spiroperidol binding and enhanced the sensitivity of striatal adenylate cyclase to DA stimulation. Prolonged L-dopa administration counteracted the increased density of (3H)-spiroperidol binding sites but further enhanced the hypersensitivity of adenylate cyclase to DA and decreased the inhibitory effect of opiates on this enzyme. The apomorphine-induced contralateral rotations were also strongly potentiated. On the contrary the binding of (3H)-SCH-23390 was affected neither by DA nerve degeneration nor by chronic L-dopa treatment. These results suggest that DA-D1 and DA-D2 receptors are differently affected by prolonged L-dopa treatment. The biochemical changes of DA-D1 receptors associated with adenylate cyclase seem to be correlated with the enhanced behavioural responses to apomorphine and could be a consequence of a decreased opiate inhibitory tone on the enzyme. The increased supersensitivity of the DA-D1 receptors may play a role in the clinical changes seen in parkinsonian patients following chronic use of L-dopa.

Adenylyl Cyclases↗
PubMed1986

Problems arising during chronic treatment with L-dopa for Parkinson's disease: changes in response to treatment.

Some aspects of the problems of long-term L-dopa treatment syndrome are reviewed, with special attention to the changes in response to treatment with dopaminergic agents, specifically end-of-dose deterioration, the on-off phenomenon and hyperkinesia. The various hypotheses for interpreting these are presented, with particular stress on changes in the function of DA-ergic receptors. It is concluded that the on-off phenomenon is probably related to changes in plasma L-dopa levels and to decreased stores of intraneural dopamine.

Corpus Striatum↗
PubMed1984

Effect of neuroleptic treatment on involuntary movements and motor performances in Huntington's disease.

Eighteen patients with Huntington's chorea were examined before and after neuroleptic treatment (haloperidol, pimozide, tiapride) to study the effect of such treatment on hyperkinesia and motor performance. Pimozide and haloperidol improved hyperkinesia; none of the drugs significantly affected motor performance. No correlation was found between the severity of hyperkinesia and motor performance scores, or between hyperkinesia and intelligence score, before and after therapy.

Adult↗