Biomedical subjects

M Stefani

Publications and source records attributed to M Stefani.

107 records · Page 6Linked to original sources

PubMedDate not supplied

Granular cells tumour in the oral cavity: report of eleven cases treated with laser surgery.

AIM: The aim of this paper is to examine the clinical and histological feature of oral tumours of neural derivation and discuss their treatment. METHODS: Between 1999 and 2004, 11 patients (6 females, 5 males; age range 28-66 years) were treated for tumours classified as being of neural origin; they were all myoblastomas or granular cells tumours (ex Abrikossoff tumour). Eight were located on the dorsum of the tongue, 2 on the lateral margin and 1 on the right buccal mucosa. In all cases the mass appeared nodular, single and firm; patients were treated in a single session by excisional resection with 808 and 830 diode laser. RESULTS: During follow-up, which ranged from 5 months to 5 years, there was no indication of tumour recurrence. Histopathological analysis of haematoxylin and eosinstained sections showed all specimens to exhibit features typical of GCT; 6 tumours were well circumscribed, whereas 5 infiltrated adjacent connective tissue, muscle fibres and nerve bundles. In 10 of the 11 cases, the immunohistochemical S-100 protein stain was available and appeared positive. Pseudo-epitheliomatous hyperplasia of different degrees was present in 5 patients, along the overlying epithelium. CONCLUSIONS: Granular cell tumour is a benign neoplasm with a tendency to relapse if not completely removed. The usefulness of laser in the surgical treatment of these tumours particularly if small in size, is underlined.

Adult↗

PubMedDate not supplied

[An atrial hematopoietic locus in the heart of the cave salamander (urodele amphibian)].

Lungless Salamanders of the family Plethodontidae have a reduced interatrial septum. The pulmonary vein is lacking. In these species, the septum as a membranous thin sheet attaches near the dorsal lip of the sino-atrial valve where a connective and muscular column, supporting the valve, extends its branches over the upper wall of the undivided atrial cavity where a sponge-like structure is formed. The meshes of this structure are the site of a erythropoietic activity as shown in the plates. Early stages in active reproduction are found in the external acid layer while in the basic inner layer the red cells undergo differentiation. This locus may be correlated to the particular anatomy of the heart concerning the lacking of the pulmonary vein, the position of the sino-arterial aperture shifted to the left side and the reduced interatrial septum. In the large upper cavity of the atrium a certain degree of blood stagnation could be possible which could allow the settlement of this locus. No ventricular erythropoiesis nor epicardial granulopoiesis have been found. This hemopoietic locus is lacking in the family Salamandridae and Anura.

Animals↗

PubMedDate not supplied

Horse muscle acylphosphatase: a more rapid purification procedure and crystallization.

A crystalline acyl phosphatase has been obtained from horse muscle. The enzyme purified by a modified procedure which allowed to obtain a larger yield with respect to a method previously developped in this laboratory, was homogeneous by disc electrophoresis on polyacrylamide gel. Crystals of this enzymatic protein have been obtained by the addition of ammonium sulphate to around 52% saturation.

Acid Anhydride Hydrolases↗

PubMedDate not supplied

Horse heart acylphosphatase: purification and characterization.

The use of an affinity chromatography step performed with an immunoadsorbent consisting of anti-horse muscle acylphosphatase antibodies covalently linked to Sepharose 4B allowed us to purify horse heart acylphosphatase in a very rapid and efficient fashion. As in skeletal muscle, also in heart the enzyme is present as both a mixed disulfide with glutathione and a S-S dimer. The abundance of these forms in heart is quite lower than in skeletal muscle. The comparison of the molecular forms so purified with those obtained from horse skeletal muscle showed the same aminoacid composition, tryptic fingerprint, together with strictly similar apparent molecular weight and main kinetic parameters, supporting the conclusion that the acylphosphatase present in heart is the same enzyme as that purified from skeletal muscle.

Acid Anhydride Hydrolases↗

PubMedDate not supplied

The complete amino acid sequence of bovine skeletal muscle acylphosphatase.

The primary structure of bovine skeletal muscle acylphosphatase was determined by performing the sequence analyses of the complete series of tryptic peptides. The amino acid composition of the entire series of peptic peptides was used to reconstruct the sequence by the overlapping method. The proposed structure is further confirmed by analogy with known amino acid sequences of acylphosphatase from skeletal muscle of other vertebrate species. The length of the polypeptide chain is 98 residues, identical to the length of the enzymes from other known mammalian species, but different from that found in turkey. The enzyme is NH2-acetylated and a comparison with the analogous molecular forms from other vertebrate species indicates that there are several long polypeptide stretches strictly conserved (93-97% identical position among mammals, and about 80% between calf and turkey enzymes).

Acid Anhydride Hydrolases↗

PubMedDate not supplied

Quantitative determination of acylphosphatase levels in horse tissues by enzyme-linked immunosorbent assay.

A non competitive enzyme-linked immunosorbent assay (ELISA) specific for horse muscle acylphosphatase (E.C. 3.6.1.7.) has been developed. The purified anti-acylphosphatase antibodies were immobilized by passive absorption to a solid-phase support and incubated with known and unknown amounts of antigen. The antibody-acylphosphatase complex was quantified using the same antibody conjugated to horseradish peroxidase. The assay yields positive reactions with as little as 0.05 ng of antigen, with intra- and interassay coefficients of variation of 5% and 7%, respectively. On the basis of this assay we developed a more sensitive test than the optical one, using benzoyl-phosphate as substrate, for acylphosphatase determination. By means of this test, the presence of the enzyme in horse tissue homogenates was evaluated under conditions in which the optical test failed to distinguish the acylphosphatase activity from that of other enzymes.

Acid Anhydride Hydrolases↗

PubMedDate not supplied