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Biomedical subjects

S Tamasi

Publications and source records attributed to S Tamasi.

11 recordsLinked to original sources
PubMed2000

Percutaneous ethanol injection of large autonomous hyperfunctioning thyroid nodules.

PURPOSE: To verify the effectiveness of percutaneous ethanol injection (PEI) in the treatment of large (>30-mL) hyperfunctioning thyroid nodules. MATERIALS AND METHODS: Twelve patients (eight women, four men; age range, 26-76 years) with a large hyperfunctioning thyroid nodule (volume range, 33-90 mL; mean, 46.08 mL) underwent PEI treatment under ultrasonographic (US) guidance. US was used to calculate the volume of the nodules and to assess the diffusion of the ethanol in the lesions during the procedure. When incomplete necrosis of the nodule was depicted at scintigraphy performed 3 months after treatment, additional PEI sessions were performed. RESULTS: Four to 11 PEI sessions (mean, seven) were performed in each patient, with an injection of 3-14 mL of 99.8% ethanol per session (total amount of ethanol per patient, 30-108 mL; mean, 48.5 mL). At scintigraphy after treatment in all patients, recovery of extranodular uptake, absence of uptake in the nodule, and normalization of thyroid-stimulating hormone (thyrotropin) levels were observed. In all patients, US showed volume reductions of 30%-50% after 3 months and 40%-80% after 6-9 months. Side effects were self-limiting in all patients. During the 6-48-month follow-up, no recurrence was observed. CONCLUSION: PEI is an effective and safe technique for the treatment of large hyperfunctioning thyroid nodules.

Adult↗
PubMed2000

[Echographic evaluation of the thymus gland in childhood].

INTRODUCTION: The thymus is a linphoepithelial organ located mostly in the anterior mediastinum and, for a smaller part, in the neck. The gland is particularly developed in the fetus and in children, while it shrinks in young adults following an involution process. We investigated the US appearance of the thymus in normal pediatric subjects to gather information for use in pediatric patients with suspected thymus conditions, using a safe, irradiation-free, technique. MATERIAL AND METHODS: We performed a US examination of the anterior mediastinum and the neck in 30 children (14 males and 16 females) ranging in age 6 months to 11 years. We used a Sonora LOGIC 700 MD General Electrics unit with 7.5-13 MHz linear probes and acquired transverse and longitudinal scans on the chest wall and the neck, integrated with intercostal scans. RESULTS: The thymus had the same echogenicity as the liver parenchyma in 22 children (73.3%), lower echogenicity in 2 (6.6%, age range 6-12 months) and higher echogenicity with heterogeneous structure in 6 children (20%, age range 8-11 years). The gland was in central and symmetric localization in 20 children (66.6%) while it exhibited a slight deviation leftwards in 7 (23.3%) and rightwards in 3 children (10%). We considered as normal the following values: in the right lobe, 1.4 cm for the AP diameter and 2.5 cm for the longitudinal one; in the left lobe, 1.4 cm for the AP diameter and 2.9 cm for the longitudinal one. DISCUSSION AND CONCLUSION: Radiological studies of the thymus are really difficult to perform because the gland is extremely variable in size, extension and shape. The thymus has the same echogenicity as the liver parenchyma and lower echogenicity than the thyroid parenchyma. We believe that US is an effective technique for studying the thymus in all its involution stages and that provides similar information to CT and MRI. Also, US does not use radiations and needs no sedation, which improves safety for young patients.

Child↗
PubMed1998

Occupancy of dipeptidyl peptidase IV activates an associated tyrosine kinase and triggers an apoptotic signal in human hepatocarcinoma cells.

Dipeptidyl peptidase IV (CD26/DPP-IV) is an ectoenzyme expressed on different cell types. Signaling properties and functional consequences of the CD26 triggering have been elucidated mostly on T cells, where the molecule delivers a costimulatory signal that potentiates T-cell activation through the T-cell receptor. We conducted studies in the human hepatocarcinoma-derived PLC/PRF/5 cell line to examine the signal transduction through CD26 and its functional properties in the absence of other T-cell-specific membrane molecules. Engagement of CD26 in PLC/PRF/5 cells through a specific antibody induces tyrosine phosphorylation of several proteins with maximal intensity 15 minutes after the stimulation. This effect was under the negative regulatory control of CD45 tyrosine phosphatase, in that the addition of orthovanadate clearly enhanced the phosphorylation events. Using in vitro kinase assays with CD26 immunoprecipitates, we observed that a protein or proteins with kinase activity are coprecipitated with the CD26 molecule. In addition, unlike Jurkat T cells, in which CD26 expression exerts a protective effect against apoptosis, in PLC/PRF/5 cells CD26 occupancy delivers a potent apoptotic signal. This effect was also observed in HepG2 cells, thus indicating that it represents a more general phenomenon occurring in different liver neoplastic cell lines.

Apoptosis↗
PubMed1997

Increased CD5+CD19+ B lymphocytes at the onset of type 1 diabetes in children.

The aim of this study was to determine whether the proportion of circulating B cells expressing the differentiative antigen CD5 was increased in children affected by type 1 diabetes, and whether the number of these cells was correlated with the presence of anti-islet cell autoantibodies. Sixteen children affected by insulin-dependent diabetes mellitus (type 1) were investigated for the presence of B lymphocytes bearing the CD5 surface molecule, T-cell-specific activation markers, organ- and nonorgan-specific autoantibodies. The number of CD5+CD19+ cells was higher in type 1 children with a very recent onset of the disease, as compared with patients on insulin therapy for more than 30 days and controls (P < 0.05). No correlation was found between the number of CD5+CD19+ cells and the presence of either organ- or nonorgan-specific autoantibodies. Our results indicate that CD5+CD19+ cells are involved in the pathogenesis of type 1 diabetes in children. A potential immunoregulatory role of this B cell population is discussed.

Age of Onset↗
PubMedDate not supplied

Novel six-nucleotide deletion in the hepatic fructose-1,6-bisphosphate aldolase gene in a patient with hereditary fructose intolerance and enzyme structure-function implications.

Hereditary fructose intolerance (HFI) is an autosomal recessive human disease that results from the deficiency of the hepatic aldolase isoenzyme. Affected individuals will succumb to the disease unless it is readily diagnosed and fructose eliminated from the diet. Simple and non-invasive diagnosis is now possible by direct DNA analysis that scans for known and unknown mutations. Using a combination of several PCR-based methods (restriction enzyme digestion, allele specific oligonucleotide hybridisation, single strand conformation analysis and direct sequencing) we identified a novel six-nucleotide deletion in exon 6 of the aldolase B gene (delta 6ex6) that leads to the elimination of two amino acid residues (Leu182 and Val183) leaving the message inframe. The three-dimensional structural alterations induced in the enzyme by delta 6ex6 have been elucidated by molecular graphics analysis using the crystal structure of the rabbit muscle aldolase as reference model. These studies showed that the elimination of Leu182 and Val183 perturbs the correct orientation of adjacent catalytic residues such as Lys146 and Glu187.

Amino Acid Sequence↗
PubMedDate not supplied

[Echographic study with high-frequency and high-spatial resolution transducer in the evaluation of renal transplant in pediatric age].

PURPOSE: We investigated the role of power Doppler US with a high-frequency and high-resolution transducer (13 MHz) in the visualization of interlobular arterioles in patients with normally functioning renal transplants or with chronic rejection. MATERIAL AND METHODS: We examined 15 patients (mean age 15 years; range 10-18 years) with a General Electric 500 MD unit using 7.5 and 13 MHz linear transducers. In all the patients serum creatinine and diuresis were evaluated; 4 patients underwent US-guided biopsy that resulted in the diagnosis of chronic rejection. RESULTS: Normally functioning renal transplants were found in 11 patients and chronic rejection was seen in 4. In normally functioning renal transplants, interlobular vessels could be depicted as "cortical blush" with the 7.5 MHz transducer; in the same patients power Doppler US with the 13 MHz transducer permitted a correct evaluation of interlobular vessels that were arranged in series like a palisade. In chronic rejection power Doppler US with the 13 MHz transducer better depicted cortical vascularity and showed irregular, narrow arteries. CONCLUSION: Power Doppler US with a 13 MHz transducer is particularly useful in children after renal transplants due to their reduced tissutal thickness. The lateral resolution of 13 MHz transducers (< 0.3 mm) allows to separate interlobular vessels from each other and the high frequency of the probe can depict interlobular vessels in the peripheral cortex. The optimal visualization of cortical vascularity with a 13 MHz transducer allows early detection of chronic rejection.

Adolescent↗