Biomedical subjects

G Schiavon

Publications and source records attributed to G Schiavon.

8 recordsLinked to original sources

PubMed1998

[Steroid therapy of hemangioma in children].

Hemangiomata is the more frequent pediatric tumor, absent at birth and usually growing, sometimes very quickly, during the first week of life. It potentially represents a serious problem because of his unforeseeable evolution during the time: is it more useful to use a corticosteroid therapy or to wait for the involution of the tumor? Here we have the results of the treatment on 51 babies who presented with hemangiomas of various sites: 52.6% of the lesions were on the face and head, 13.4% on chest wall, 10% on upper limbs, 4% on abdominal wall, 10% on pelvis region and 10% multiple. Therapy was compression in 10% of patients, corticosteroid injection in 66%, oral administered corticosteroid in 12%, surgery post corticosteroid therapy in 11.5%, others in 2.5%. Best results were obtained on the lesion of the head and face (good in 96%), worst in those of the abdomen (any modification in 100%).

Adrenal Cortex Hormones↗

PubMed1997

[Phimosis: when does it require surgical intervention?].

One of the most recurrent questions in pediatric age is the phimosis; this is a frequently underestimated problem and its resolution often cause a lot of discomforts in babies and parents. In many countries it has been treated on the roots of ancient sanitary measures (circumcision) whereas in others it's routinely treated with painful and useless maneuvers; instead, until three years of age this don't represents a problem but the normal situation of the baby. Herein the authors report the results of topic corticosteroid treatment of fimosis in 83 patients aged 1-14 years, with good outcome in 86.7% of cases. Therapy and results are discussed.

Administration, Topical↗

PubMed1992

Isolated blunt liver trauma: is nonoperative treatment justified?

During the past 8 years 13 children with isolated blunt liver trauma were managed nonoperatively. All patients selected for this management were hemodynamically stable after initial resuscitation and were without signs of other associated intraabdominal injuries on ultrasonogram and/or computed tomography. Patients were observed in an intensive care unit for at least 48 hours with repeated clinical assessments, laboratory studies, and bed rest. One patient with type 3 injury was operated on 8 days after injury because of sudden intraperitoneal bleeding on ambulation. Five patients required blood transfusions of not more than 300 mL per patient. Laboratory values returned to normal from 7 to 21 days after injury. Resolution of hepatic injury on ultrasonogram took from 1 to 3 months. Complete bed rest was prescribed for at least 10 days depending on the type of injury, with restricted activities up to 3 months postinjury. No complications were seen in this series.

Adolescent↗

PubMed1991

Improved high-performance liquid chromatographic determination with amperometric detection of alpha-amanitin in human plasma based on its voltammetric study.

A sensitive and simple method is described for the selective determination in human plasma of alpha-amanitin, the most poisonous and prevalent toxin in the lethal fungi of species Amanita, using high-performance liquid chromatography with amperometric detection. After an extraction of plasma with disposable C18 silica cartridges, the extracts were separated by isocratic reversed-phase chromatography using a macroporous poly(styrene-divinylbenzene) column and a mobile phase of 0.05 M phosphate buffer-acetonitrile (91:9) at the apparent pH of 9.5. Amperometric detection was performed by applying an oxidation potential as low as +350 mV (vs. Ag/AgCl) to a glassy carbon electrode, in a thin-layer flow-cell. The linear range for alpha-amanitin was 3-200 ng/ml, and the relative limit of detection in plasma was 2 ng/ml at a signal-to-noise ratio of 2. The intra-assay precision was evaluated at levels of 10 and 200 ng/ml; the coefficients of variation were 4.5 and 2.6% (n = 5), respectively. Inter-assay coefficients of variation were 6.5 and 4.2% (n = 5) for the same concentrations of toxin. These analytical conditions have been chosen on the basis of a preliminary in batch cyclic voltammetric investigation of alpha-, beta- and gamma-amanitins, which has allowed their oxidation process to be clarified and the pH dependence of their oxidation potentials to be determined. All three amanitins are oxidized at the same potential values, and adsorption onto the electrode surface of both reactant and products was found in all cases. This adsorption did not affect the signal recorded for alpha- and gamma-amanitins at the amperometric detector, and for beta-amanitin a stronger adsorption for the anodic product was found, which leads to a marked positive shift of the potential required for the oxidation of this isomer in the amperometric detector cell.

Amanitins↗

PubMed1991

Development of post-column enzymic reactors with immobilized alcohol oxidase for use in the high-performance liquid chromatographic assay of alcohols with electrochemical detection.

The development of a very sensitive, direct injection high-performance liquid chromatographic method, using a post-column reactor with immobilized alcohol oxidase, was undertaken with the aim of determining methanol and ethanol levels in microlitre volumes of biological samples. After reversed-phase chromatography to separate methanol and ethanol, the analytes were enzymically converted into the respective aldehydes with formation of stoichiometric amounts of hydrogen peroxide, which could be measured via electrochemical oxidation at a platinum electrode. Some problems were encountered in the development of solid-phase enzymic reactors, using a delicate enzyme, that is prone to lose activity, such as alcohol oxidase. Owing to the slightly alkaline pH required for the optimum activity of alcohol oxidase, polymeric columns seemed to be preferable for the chromatography. HEMA copolymer was chosen as the stationary phase, but the methanol and ethanol peaks eluted close together and posed severe problems of limiting post-column band spreading. Reactors based on coarse supports for enzyme immobilization gave unacceptable band spreading, causing the methanol and ethanol peaks to overlap. On the other hand high-performance liquid chromatographic packings maintained the efficiency of the chromatographic separation, quite independently of the reactor volume. Polymeric supports proved superior to silicas in maintaining the enzyme activity. However, relevant changes in the enzyme substrate specificity were observed after immobilization.

Alcohol Oxidoreductases↗

PubMed1991

[The hypothesis of a diagnostic-prognostic assessment of intestinal invagination with the aim of treatment by echo-guided pneumatic reduction].

The authors investigated the role of US in the diagnostic-prognostic evaluation of enteric intussusception, for the use of US-guided pneumatic reduction (RPEG). In the last 5 years, 59 young patients were examined; 44 of them had clinically suspected enteric intussusception which was confirmed by US. US allowed site and nature of the condition to be demonstrated (sensitivity and specificity: 100%), while supplying helpful predictive prognostic elements as to the extent of intussuscepted loop involvement (predictive prognostic value: 100%). On the contrary, its etiological screening capabilities were poor (11%) in the identification of secondary forms (5 ileal diverticula). A grading score was introduced to select the patients undergoing RPEG. Six clinical and US parameters were considered, with values increasing according to severity of the condition. The higher the score, the lower the chances of therapeutical success with RPEG. In 3 cases (2 loop necroses and 1 severe intestinal obstruction) with US score greater than 6 [9] and clinical score greater than 11 [15], RPEG, was replaced by surgery. Fourteen patients underwent RPEG: positive results were obtained in 12 cases (85%). In one case, a short-term relapse (within 6 hours) was observed.

Acute Disease↗

PubMed1990

Use of enzymatic reactors in the high performance liquid chromatographic determination of ethanol and methanol with electrochemical detection.

Despite numerous applications both in industry and in analytical chemistry, immobilized enzyme technology has encountered only limited success in modern liquid chromatography. The strict requirements of enzymatic reactors for high performance liquid chromatography (HPLC) (i.e., mechanical resistance, limited void volumes, high contact surface, high binding capacity, stable enzyme-to-matrix bond without loss of enzyme activity) are not yet fully met by commercially available products. In our laboratory, the development of post-column reactors with immobilized alcohol oxidase on-line with an HPLC/EC system has been undertaken. Three home-made reactors were produced: in the first alcohol oxidase from Candida boidinii was quasi-immobilized onto an HPLC-sized anion exchange support, in the second the enzyme was bound to a silica-based support via Schiff's base formation, and in the third a covalent linkage to an epoxy-activated hydroxyalkyl methacrylate material was chosen. Chemical immobilization proved superior to the ionic binding. The importance of limiting the post-column band spreading due to the reactor void volume, by using HPLC-size supports, was confirmed.

Chromatography, High Pressure Liquid↗

PubMedDate not supplied

[Hepatic hemangioma in the neonate: description of a case treated surgically with favorable outcome].

The authors describe a case of hepatic hemangioma in a newborn, treated by successful surgical resection. Neonatal hepatic hemangioma is able to produce congestive heart failure with high output, thrombocitopenia, spontaneous rupture with peritoneal hemorrhage and sudden death. The major symptoms are a palpable anterior abdominal mass, tachicardia, and congestive heart failure unrespansive to medical treatments; sometimes there are cutaneus hemangiomas. When diagnosis is made, surgical resection is necessary in the solitar hemangioma; for diffuse or multinodular hemangiomatosis radiotherapy, corticosteroids and hepaticartery ligation have been employed with some good results.

Hemangioma↗