Publications by authors named "FLORIS R"

The authors report neurologic features in a large family harboring the mitochondrial DNA (mtDNA) mutation T14484C associated with Leber hereditary optic neuropathy (LHON). In the maternal line the mtDNA mutation was associated with optic neuropathy or migraine with aura or without aura and transient neurologic/visual disturbances. The segregation of familiar cases of migraine and LHON mutation broadens the clinical phenotype associated with a primary LHON mutation.

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Fluid-attenuated inversion recovery (FLAIR) sequence is currently used in clinical practice. Some reports emphasize the possibility that, in pathologic conditions, intravenous injection of gadolinium chelates may lead to an increased signal inside the cerebrospinal fluid (CSF). The aim of this study was to evaluate the presence of CSF signal changes in pathologic conditions causing blood-brain barrier disruption or neovascularization when imaging is performed after intravenous injection of gadolinium.

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Relative regional blood flow of basal ganglia was studied by means of perfusion-weighted dynamic susceptibility (DSC) MRI. Parkinson's disease (PD) patients showed a significant inter-hemispheric asymmetry due to a higher perfusion in the more affected side, while normal subjects did not. PD exhibited an abnormal "asymmetry index" in the measured nuclei.

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Purpose: To study the possible correlation between interictal EEG patterns and neuroradiologic data obtained by dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI) in patients with partial epilepsy.

Methods: Seventeen subjects with cryptogenic partial epilepsy underwent long-term video-EEG monitoring and DSC-MRI in the same session. Ten patients had temporal lobe epilepsy (TLE) and seven, epilepsy of extratemporal origin (ExTE).

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Background And Objectives: Allogeneic bone marrow transplantation (BMT) is a widely accepted therapeutic approach in homozygous beta-thalassemia. However, the majority of patients do not have a genotypically identical donor within the family. This prompted us to conduct a pilot study to investigate the feasibility of matched unrelated bone marrow transplantation in thalassemia.

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Background And Purpose: Risk of developing ischemia is higher in patients with reduced cerebrovascular reactivity than in those with preserved cerebrovascular reactivity. Therefore, we assessed cerebral hemodynamic modifications in patients with unilateral stenosis of the internal carotid artery by using perfusion-weighted MR imaging to determine if these modifications underlie or anticipate ischemic signs and symptoms.

Methods: Fifteen patients with unilateral 70-90% carotid artery stenosis were studied with digital subtraction angiography and perfusion-weighted MR imaging.

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We studied five patients with multiple sclerosis with one plaque of demyelination more than 2 cm in diameter, using conventional and diffusion-weighted MRI, soon after the onset of symptoms and over 1-36 months. The orientationally averaged diffusion coefficient was increased in all the acute lesions, and increased further during follow-up in three. There was a strong correlation between and the degree of low signal on T1-weighted images.

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In a search for natural proteins with anti-HIV activity, we screened a large set of purified proteins from bovine milk and peptide fragments thereof. Because several charged proteins and peptides are known to inhibit the process of virus entry, we selected proteins with an unusual charge composition or hydrophobicity profile. In contrast with some chemically modified (strongly negative) milk proteins, unmodified alpha(s2)-, beta- and kappa-casein, as well as several negatively and positively charged fragments thereof, did not show significant inhibition of virus replication.

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The substitution of human serum albumin with negatively charged molecules, such as succinic acid (Suc-HSA) or aconitic acid (Aco-HSA), resulted in proteins with potent anti-HIV activities, by binding to viral gp120 (V3 loop). The aim of the present study was to investigate whether the distribution of negative charges on the albumin backbone influences the anti-HIV activity. Therefore, we prepared albumins with clusters of negatively charged groups by coupling of heparin.

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A case of bilateral synovial cysts is reported. They were shown by MRI first on one side and later, on the contralateral side, concomitantly with a reduction in the size of the cyst. Because spine instability was also present the most acceptable assumption is that there may be a contiguity between the articular facets and the cysts, thus enabling the filling and emptying of the cysts itself.

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The alpha-amino acid ester hydrolase from Acetobacter turbidans ATCC 9325 is capable of hydrolyzing and synthesizing beta-lactam antibiotics, such as cephalexin and ampicillin. N-terminal amino acid sequencing of the purified alpha-amino acid ester hydrolase allowed cloning and genetic characterization of the corresponding gene from an A. turbidans genomic library.

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Epilepsia partialis continua (EPC) may occur during nonketotic hyperglycemia but has not been described with diabetic ketoacidosis. The authors report a patient with EPC associated with ketotic hyperglycemia. Brain MRI showed two areas of abnormal signal intensity in the left precentral gyrus and in the right cerebellar hemisphere.

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Background And Purpose: Perfusion imaging with dynamic susceptibility contrast MR imaging (DSC-MRI) has been used to evaluate hemodynamic status in patients with symptomatic occlusive cerebrovascular disease. The aim of the present study was to determine the hemodynamic changes occurring in asymptomatic patients with unilateral internal carotid artery (ICA) occlusion by use of DSC-MRI with transcranial Doppler (TCD) measurement of the breath-holding index (BHI).

Methods: Nine patients with asymptomatic unilateral ICA occlusion underwent DSC-MRI and TCD examination.

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Background And Purpose: Perfusion and diffusion-weighted MR imaging are powerful new imaging techniques for evaluating tissue pathophysiology in association with many neurologic disorders, such as neurodegenerative diseases. The purpose of our study was to evaluate the sensitivity and specificity of dynamic susceptibility contrast-enhanced MR imaging and diffusion-weighted MR imaging in cases of Alzheimer's disease and to assess the role of atrophy in the quantification of cortical perfusion.

Methods: Thirty-nine participants were studied: 18 patients with moderate cognitive impairment with probable Alzheimer's disease, 16 patients with mild impairment with possible or probable Alzheimer's disease, and 15 group-matched elderly healthy comparison volunteers.

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Purpose: The aim of the study was to compare gadolinium-enhanced MRA (Gd-MRA), Computed Tomography angiography (CTA) and digital subtraction angiography (DSA) in the evaluation of carotid stenosis.

Material And Methods: Thirty patients with US-proven internal carotid artery stenosis over 50%, underwent Gd-MRA, CTA and DSA. Gd-MRA was acquired using the keyhole technique.

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The binding of penicillin to penicillin acylase was studied by X-ray crystallography. The structure of the enzyme-substrate complex was determined after soaking crystals of an inactive betaN241A penicillin acylase mutant with penicillin G. Binding of the substrate induces a conformational change, in which the side chains of alphaF146 and alphaR145 move away from the active site, which allows the enzyme to accommodate penicillin G.

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Malignant autosomal recessive (AR) osteopetrosis represents an absolute indication for bone marrow transplantation (BMT). Over the last 15 years, almost 100 BMTs for osteopetrosis have been reported. The median age at transplant of most patients is 4 months.

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Purpose: To evaluate the efficacy of diffusion weighted Magnetic Resonance Imaging in the diagnosis of acute ischemic infarction and correlate the signal changes observed in the acute phase with final brain damage.

Material And Methods: Fifteen patients (six women and nine men: mean age 68 years) with acute ischemic stroke (within 12 hours) underwent diffusion MRI. All the patients were selected on the basis of sudden focal neurologic symptoms and CT findings excluding other conditions than ischemia.

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Determination of kinetic parameters of penicillin acylases for phenylacetylated compounds is complicated due to the low K(m) values for these substrates, the lack of a spectroscopic signal, and the strong product inhibition by phenylacetic acid. To overcome these difficulties, a spectrophotometric method was developed, with which kinetic parameters could be determined by measuring the effects on the hydrolysis of the chromogenic reference substrate 2-nitro-5-[(phenylacetyl)amino]benzoic acid (NIPAB). To that end, spectrophotometric progress curves with NIPAB in the absence and presence of the phenylacetylated substrates and their products were measured and analyzed by numerical fitting to the appropriate equations for competing substrates with product inhibition.

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The effect of various monovalent, divalent and oligovalent cations on the reaction of triplex formation by GT and AG motif triplex-forming oligonucleotides, designed to bind to biologically relevant polypurine-polypyrimidine sequences occurring in the promoters of the murine Ki-ras and human bcr genes, has been investigated by means of electrophoresis mobility shift assays (EMSA) and DNase I footprinting experiments. We found that in the presence of 10 mm MgCl2 the triple helices were progressively destabilized by adding increasing amounts of NaCl, from 20 to 140 mm, to the solution. We also observed that, while the total monovalent-ion concentration was constant at 100 mm, the exchange of sodium with potassium, but not lithium, results in a further destabilization of the triple helices, due to self-association equilibria involving the G-rich triplex-forming oligonucleotides.

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Haloalkane dehalogenase (DhlA) hydrolyzes short-chain haloalkanes to produce the corresponding alcohols and halide ions. Release of the halide ion from the active-site cavity can proceed via a two-step and a three-step route, which both contain slow enzyme isomerization steps. Thermodynamic analysis of bromide binding and release showed that the slow unimolecular isomerization steps in the three-step bromide export route have considerably larger transition state enthalpies and entropies than those in the other route.

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Three molecular techniques (RAPD-polymerase chain reaction analysis, plasmid profile and pulsed-field gel electrophoresis) were used for a preliminary approach to type, at strain level, enterococci isolated from a 24-h-old home-made Pecorino Sardo (protected designation of origin) cheese. A high genetic polymorphism was found. Clusters obtained by the RAPD technique and plasmid profile analysis contained different strains.

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Cerebrospinal fluid (CSF) leakage after trans-sphenoidal surgery is a troublesome complication with a risk of meningitis and pneumocephalus. We suggest CT-guided intrasphenoidal injection of fibrin sealant through a 12-gauge needle as a simple alternative to surgical management of CSF fistulae. We treated eight patients, operated via the trans-sphenoidal route (five pituitary adenomas, three craniopharyngiomas), for a postoperative CSF leak by CT-guided intrasphenoidal injection of fibrin sealant alone in three cases and fibrin sealant and autologous blood in 5.

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Introduction: Some clinical trials (NASCET, ECTS) have assessed that carotid endarterectomy is protective against stroke in patients with asymptomatic severe carotid stenosis. In order to decrease costs and risks, new diagnostic tools have been developed, such as Magnetic Resonance Angiography (MRA), duplex Ultrasound (US) and more recently Spiral Computed Tomography Angiography (CTA). CTA provides excellent 3D angiography images of the extracranial vessels using a volume rendering technique.

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