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Biomedical subjects

R Barone

Publications and source records attributed to R Barone.

At least 55 records · Page 3Linked to original sources
PubMed1999

Rett syndrome: photographic evidence of rapid regression.

Rett Syndrome is known to occur in females, around the second year, with loss of hand use, onset of stereotypes and acquired microcephaly. Such regression is often very rapid, but this has never been documented. In one of our patients, photographs taken at different times clearly demonstrate the rapid progression of first symptoms. Moreover, in the present case, the occurrence of a febrile illness, which preceded the onset of the neurological picture, support the hypothesis that environmental factors may trigger the onset of Rett Syndrome in genetically predisposed subjects.

Adolescent↗
PubMed1999

Interleukin 2 gene therapy of colorectal carcinoma with autologous irradiated tumor cells and genetically engineered fibroblasts: a Phase I study.

The purpose of this study was to determine the safety, toxicity, and antitumor immune response following S.C. immunizations with a mixture of irradiated, autologous tumor cells and autologous fibroblasts that were genetically modified to express the gene for interleukin 2 (IL-2) in patients with colorectal carcinoma. Ten patients were treated with a fixed dose of tumor cells (10(7)) and escalating doses of fibroblasts secreting IL-2 (per 24 h): 100 units (three patients), 200 units (three patients), 400 units (three patients), and 800 units (one patient). Pre- and posttreatment peripheral blood mononuclear cells were evaluated for evidence of antitumor immune responses. Fatigue and/or flu-like symptoms were experienced by seven patients and delayed-type hypersensitivity-like skin reactions were observed at the sites of the second or subsequent vaccinations in five patients. Low frequencies of tumor cytotoxic T-cell precursors (range, 1/190,000-1/1,320,000 peripheral blood mononuclear cells) were detected prior to therapy in four of seven patients. There was a 5-fold increase following treatment in the frequency of tumor cytotoxic T-cell precursors in two of six evaluable patients. Some patients with colorectal cancer have low frequencies of tumor cytotoxic T-cell precursors that may be increased by this well-tolerated form of IL-2 gene therapy, which warrants continued clinical evaluation.

Cancer Vaccines↗
PubMed1999

Localized soft tissue ridge augmentation at phase 2 implant surgery: a case report.

A case of congenitally missing maxillary lateral incisors is presented to illustrate a modification of Abrams's roll technique. Buccal releasing incisions are avoided by using an intrasulcular incision on the adjacent teeth. The tissue overlying the cover screw is transferred between the buccal cortical bone and the buccal masticatory mucosa, thus correcting the localized buccal ridge atrophy.

Adult↗
PubMed1998

Prognostic relevance of pancreatic uptake of technetium-99m labelled human polyclonal immunoglobulins in patients with type 1 diabetes.

Insulin-dependent type 1 diabetes (IDDM) is caused by the autoimmune destruction of insulin-producing beta cells. Approximately 10%-20% of patients may benefit from adjuvant immunotherapy upon diagnosis of the disease in order to protect residual beta-cell function. It has been suggested that this subgroup of patients differs from others by virtue of the presence of residual pancreatic inflammation and beta-cell function. In this study we have investigated to what extent technetium-99m-labelled human polyclonal immunoglobulins (99mTc-HIG) accumulate in the pancreas of IDDM patients at the time of diagnosis and 1 year thereafter, with a view to ascertaining whether HIG scintigraphy is useful for the identification of IDDM patients with residual pancreatic inflammation. Patients with recent-onset IDDM (n=15) were investigated at the time of diagnosis and 1 year later, and ten age- and sex-matched normal subjects were also studied. Gamma camera imaging and target to background ratio, analysed blind by three independent readers, were used to quantify the radioactivity in the pancreatic region and findings were correlated with metabolic, immunological and clinical parameters. Seven out of 15 newly diagnosed IDDM patients showed a significant accumulation of radiolabelled HIG in the pancreas (pancreas/bone ratio higher than the mean +2SD of normal subjects). One year after diagnosis, pancreatic accumulation of HIG was still detectable in most IDDM patients who were positive at the time of diagnosis. Six out of seven patients with positive scintigraphy had a partial clinical remission. These results indicate that HIG scintigraphy at the time of onset of diabetes identifies a subset of patients with residual beta-cell function who may benefit from adjuvant immunotherapy.

Adolescent↗
PubMed1998

Lysosomal enzyme activities in serum and leukocytes from patients with carbohydrate-deficient glycoprotein syndrome type IA (phosphomannomutase deficiency).

From 10 patients with carbohydrate-deficient glycoprotein (CDG) syndrome due to phosphomannomutase (PMM) deficiency, out of 10 lysosomal enzymes, 7 enzyme activities were measured in serum and 9 in leukocytes. In serum there was a 2-fold to 4-fold increase in activity of beta-glucuronidase, beta-hexosaminidase, beta-galactosidase, and arylsulphatase A. In leukocytes, however, several enzymes had reduced activity, particularly alpha-fucosidase, beta-glucuronidase and alpha-mannosidase. These abnormalities could result from missorting, defective reuptake and/or reduced stability of the enzymes due to the defective glycosylation.

Congenital Disorders of Glycosylation↗
PubMed1998

A protocol for maintaining or increasing the width of masticatory mucosa around submerged implants: a 1-year prospective study on 53 patients.

Masticatory mucosa around implants may be useful to enhance esthetics and/or plaque control. This study proposes simplified guidelines for maintaining or obtaining a minimal amount of masticatory mucosa around submerged implants in cases of partial edentulism, and for keeping the need for additional surgery to a minimum. Free gingival grafts were used in the mandibular arch when the width of buccal masticatory mucosa was less than 2 mm. The width of masticatory mucosa expected to be available for attachment to the bone surface buccal to implants was estimated by measuring the distance between the emergence of the implant from bone and the mucogingival junction. When this distance was 3 mm or less, the use of an apically positioned flap for implant exposure was preferred over gingivectomy. The amount of masticatory mucosa buccal to implants was measured 2 weeks, 6 months, and 12 months after implant exposure. In no case was the width of masticatory mucosa less than 2 mm at 1 year. Therefore, this protocol is recommended for the treatment of cases where the presence of an adequate amount of masticatory mucosa is necessary to ensure a satisfying appearance or is useful for facilitating oral hygiene.

Adult↗
PubMed1997

Two new mild homozygous mutations in Gaucher disease patients: clinical signs and biochemical analyses.

Gaucher disease (GD) is a lysosomal storage disorder resulting from impaired activity of lysosomal beta-glucocerebrosidase. More than 60 mutations have been described in the GBA gene. They have been classified as lethal, severe, and mild on the basis of the corresponding phenotype. The fact that most GD patients are compound heterozygous and that most type 1 patients bear the N370S allele, which by itself causes a mild phenotype, make it difficult to correlate the clinical signs with the mutations. Besides N370S, about 10 mild mutations have been described, but only one undoubtedly classified as mild was found at homozygosity. Here we report 2 novel mutations, I402T and V375L, at homozygosity in 2 adult Italian type 1 GD patients. Some properties of the I402T fibroblast enzyme have been compared to those of the enzyme from cells of several N370S/N370S patients. Analysis of the catalytic properties and heat stability as well as the response to phosphatidylserine and sphingolipid activator protein indicate a marked similarity between the 2 enzymes. The finding of another, unrelated patient bearing the I402T mutation (in this case as a compound heterozygote with mutation N370S) suggests that this allele might be quite frequent in the area of Sicily from where both patients originated. In conclusion, the phenotypic expression in the 2 homozygous patients presented here and the biochemical data for one of them allowed the classification of these mutations as mild thus extending the group of mild mutations found at homozygosity.

Adult↗
PubMed1997

Effects of temperature and SDS on the structure of beta-glycosidase from the thermophilic archaeon Sulfolobus solfataricus.

The effects of temperature and SDS on the three-dimensional organization and secondary structure of beta-glycosidase from the thermophilic archaeon Sulfolobus solfataricus were investigated by CD, IR spectroscopy and differential scanning calorimetry. CD spectra in the near UV region showed that the detergent caused a remarkable change in the protein tertiary structure, and far-UV CD analysis revealed only a slight effect on secondary structure. Infrared spectroscopy showed that low concentrations of the detergent (up to 0.02%) induced slight changes in the enzyme secondary structure, whereas high concentrations caused the alpha-helix content to increase at high temperatures and prevented protein aggregation.

Bacterial Proteins↗
PubMed1997

Identification of the active site nucleophile in the thermostable beta-glycosidase from the archaeon Sulfolobus solfataricus expressed in Escherichia coli.

Sulfolobus solfataricus beta-glycosidase expressed in Escherichia coli was fully inactivated at 65 degrees C, according to pseudo-first-order kinetics, by [3H]conduritol B epoxide (DL-1,2 anhydro-myo-inositol) synthesized as the active site directed inhibitor by a slight modification of Legler's procedure [Legler, G. (1977) Methods Enzymol. 46, 368-381]. The determination of kinetic constants for the inactivation showed that the process took place through the formation of a stabilized inhibitor-enzyme intermediate. Inactivation and reactivation studies suggested that the inhibitor-enzyme intermediate complex was formed more rapidly and hydrolyzed at a lower rate than it was for other glycosidases. Moreover, the stoichiometry of the binding, determined by electrospray mass spectrometric analysis, revealed that one molecule of the inhibitor was covalently bound to each enzyme subunit. The binding site for [3H]conduritol B epoxide was identified by the isolation and partial sequence analysis of the radioactive peptide obtained by cyanogen bromide and pepsin digests. Electrospray tandem mass analysis of the labeled peptide showed that the inhibitor was covalently bound to E387. This result, in agreement with data obtained from sequence alignments of S. solfataricus beta-glycosidase with other gluco- and galactosidases of the glycosyl hydrolase family 1 [Henrissat, B. (1991) Biochem. J. 280, 309-316], indicates that the conserved E387 is the nucleophilic amino acid residue in the active site of the enzyme.

Amino Acid Sequence↗
PubMed1997

[Enzyme replacement therapy: a new treatment concept in Gaucher disease].

Until recently the treatment of lysosomal storage disorders was entirely supportive. A new enzyme replacement therapy has become available in Gaucher's disease, a lipid storage disorder that is due to a genetic defect of beta-glucocerebrosidase. Intravenous infusions of modified beta-glucocerebrosidase has produced clinical improvement in Gaucher patients, with regression of organomegaly and increase in blood counts. At the Children's Hospital of Mainz 13 patients (6 children and 7 adults) were treated with alglucerase on a high-dosage regimen (60 units per kilogram every two weeks). A decrease in liver and spleen size was observed 4 to 6 months after commencement of therapy. Hemoglobin and the number of platelets increased. In some cases, a reduction of the dosage was possible after a year of enzyme replacement-therapy. A growth spurt was observed in the children. The availability of enzyme replacement therapy is limited by its high cost; however, in the future gene transfer may become the treatment of choice.

Adolescent↗
PubMed1996

Evidence for genetic heterogeneity in the carbohydrate-deficient glycoprotein syndrome type I (CDG1).

We have analyzed a series of polymorphic markers on chromosome 16p13 in 17 families with carbohydrate-deficient glycoprotein syndrome type I (CDG1). First, linkage to the region between D16S406 and D16S500 is confirmed. The telomeric border of the candidate region is now definitively placed proximal to D16S406 by crossovers observed in 2 families. Second, in 1 family with 2 affected siblings, the disease is not linked to chromosome 16p. Genetic heterogeneity has not been previously reported for CDG1, and this observation has implications for prenatal diagnosis. Third, allelic associations suggest that the disease locus is localized close to D16S414/D16S497. This places the region of interest centromeric of its published localization.

Chromosomes, Human, Pair 16↗
PubMed1996

Clinical and neuroradiological findings in classic infantile and late-onset globoid-cell leukodystrophy (Krabbe disease).

In the present study the clinical course and imaging of early and late-onset forms of Krabbe disease are analyzed. We report on 11 patients with a biochemical diagnosis of galactosyl ceramide beta-galactoside deficiency. Two presented as the classic infantile form and died within the second year of life. In 9 children the first clinical signs, such as gait difficulties and visual failure, started after age 2 years. All these patients developed slow regression of motor and mental capacities, and most of them died within their first decade. In patients of both groups computed tomography (CT) and magnetic resonance imaging (MRI) were performed. In the late-onset form, hypodensities of the central white matter and pyramidal tracts were the leading radiological signs, whereas in the early-onset form, hyperdensities and cerebellar white matter lesions were also detected. From our results it becomes clear that variability of Krabbe disease refers not only to clinical manifestation but also to CT and MRI findings. Better knowledge of phenotypic and radiological diversity will help to understand the pathogenesis of the disease.

Age of Onset↗
PubMed1996

Frequency and distribution of NF2 mutations in schwannomas.

Sporadic and inherited schwannomas were scanned for the nature, frequency, and distribution of mutations in the NF2 locus encoding the merlin tumor suppressor protein on 22q. Of 58 tumors, 47% displayed loss of heterozygosity for NF2, leaving a total of 89 NF2 alleles to be examined. Pathogenic alterations were identified in 62 of these alleles, including 36 frameshifts with premature termination, 14 nonsense mutations, and 12 changes presumed to affect splicing. Effects of ten of the latter were confirmed in the NF2 transcript and indicated that activation of cryptic splice sites in coding sequence is another frequent mechanism leading to truncation of merlin. The mutations were relatively evenly distributed across both the protein 4.1 superfamily (exons 1-9) and the alpha-helical (exons 10-15) domains of merlin, but they did not occur at all in exons 16 and 17, which encode the protein's alternative COOH-termini. The data support the "two-hit" tumor suppressor model for formation of schwannomas and indicate that loss of merlin function can be achieved by truncation at various locations in the protein. However, the absence of mutations in exons 16 and 17 suggests that an inactivating mutation affecting only one of the merlin's alternative termini may not be sufficient to eliminate tumor suppressor function.

Adult↗