Biomedical subjects

C Marchetti

Publications and source records attributed to C Marchetti.

At least 91 records · Page 5Linked to original sources

PubMed1994

Ameloblastic fibrosarcoma of the jaw: report of five cases.

Five cases of ameloblastic fibrosarcomas (AFS) are reported. The tumour was characterized histologically by a biphasic pattern: the malignant mesenchymal component had the features of an intermediate grade fibrosarcoma in 3 cases, malignant fibrous histiocytoma and osteogenic sarcoma in 2 cases. The epithelial odontogenic component had a benign appearance cytologically. In 1 patient, in the recurrence only the malignant mesenchymal component was present. AFS is a fully malignant tumour, in fact 1 patient died of the tumour after inadequate surgical treatments, and 2 patients had a recurrence after intralesional surgery. The treatment of choice was achieved when surgery with wide surgical margins was performed. As MFH and OGS features are present in the malignant mesenchymal component of this tumour we prefer to use the broad term ameloblastic sarcoma instead of AFS.

Adolescent↗

PubMed1994

Is there a cognitive impairment in MND? A survey with longitudinal data.

Twenty-nine patients affected by motor neuron disease (MND) were investigated with the Raven Progressive Matrices, a test of logical non verbal intelligence, requiring neither motor nor verbal skills. The score distribution of the MND patients did not differ from that of 321 controls. Eleven of these patients were retested after a mean interval of 8.5 months. The resulting differences in the test scores showed that their intellectual performance had not worsened over time. Even allowing for the limitations posed by the use of a single test, these data add to the evidence against systematic cognitive involvement in MND.

Adult↗

PubMed1994

Collagen fiber arrangement in temporo-mandibular joint (TMJ) disks from human subjects with functional diseases. Scanning electron microscopy investigations.

Twelve articular disks from patients with temporo-mandibular joint (TMJ) arthropathy were studied and compared with two normal disks. Scanning electron microscopy (SEM) examination of the surfaces and of longitudinal and cross-sections of the disks allowed the observation of the arrangement of the collagen fiber component in different parts of the disk. The superficial part of the articular disks appears to be formed by rather compact fibers. The internal portion is usually formed by bundles of collagen fibers in sheets, alternating with isolated fibers arranged in a parallel or irregular way. In some samples, blood vessels were observed. Our investigations suggested that the appearance of vascularization is the first remarkable histological change that can be observed in functionally abnormal articular disks.

Collagen↗

PubMed1994

[Modern imaging of maxillofacial deformities].

Facial malformations make a wide chapter of maxillofacial abnormalities whose treatment needs an accurate clinical-instrumental analysis to quantify malformation entity and to agree on precise lesion classification and subsequent management. Maxillofacial abnormalities are classified as congenital, growth-related and acquired. Congenital deformities include the alterations present at birth, i.e., craniofacial stenosis, oto-mandibular syndrome. Treacher-Collins and Goldenhar syndrome, facial clefts and lip-palate clefts. Growth-related malformations include the deformities appearing during growth and which are called maxillary dysmorphosis, e.g., hemimandibular hyperplasia, prognathism, maxillary hypoplasia, etc. Acquired malformations are those remaining after trauma or cancer surgery and those which are secondary to fibrous dysplasias of the craniofacial complex. May 1990 through May 1993, forty-two patients with different malformations were examined. The malformations secondary to cancer surgery were not included in our series. A radiologic study including conventional skull radiography, teleradiography and panoramic tomography had been performed for preliminary assessment before axial CT studies and 2D and 3D reconstructions. As for our series, in 20 patients coventional radiology was exhaustive to diagnose the disorder and to supply essential elements for treatment planning while axial CT and 3D reconstructions added no further piece of information. Only in the most complex malformations and in all cases of congenital malformations was axial CT needed to assess the type, extent and entity of the malformations allowing both the diagnosis and adequate surgical planning.

Adolescent↗

PubMed1994

[Brachytherapy in choroid tumors].

Even though brachytherapy has been used for many years to treat choroidal tumors, it is not a widespread technique because it requires much organization and operators skills. The most common methods use 60Cobalt and 106Rutenium plaques, or custom-made plaques with 125Iodine loaded seeds. Another, less common, technique uses 192Iridium wires loaded on custom-made plaques. The technique we used to treat 4 retinoblastomas and 2 choroidal melanomas uses 192Iridium wires loaded on custom-made plaques. The applicator is made of a quick drying paste poured over a sphere the same size as the eye-ball: plastic tubes are inserted, according to preliminary dosimetric measurements, to house the Iridium wires. The applicator is positioned on the eye-ball corresponding to tumor site by surgery. The Iridium sources are inserted into the plastic tubes at the end of surgical placement: this afterloading technique guarantees maximal staff protection. 192Iridium (320 keV gamma emitter) allows the dose to be transmitted deeper than with 125Iodine (30 keV gamma-emitter) and 106Rutenium (3540 keV beta-emitter). Therefore, with Iridium, the dose delivered is lower on the eye-ball surface for the same tumor dose. On the other hand, the use of 60Cobalt (1250 keV gamma-emitter) gives the healthy surrounding tissues higher doses. To conclude, this method allows us to customize the application to every single case, to reach posterior sites, to ensure radioactive protection to staff thanks to afterloading and to obtain a good depth to surface dose ratio.

Brachytherapy↗

PubMed1994

Distribution of CII and CIII peptides in lipoprotein classes: methods and clinical significance.

We describe a method for measuring apolipoprotein (apo) C distribution between apo B-containing lipoprotein (apo B-LP) and non-apo B-LP. The procedure requires the precipitation of apo B-LP, the redissolution of the pellet, and the quantification of C peptides in the redissolved pellet. The ratio of apo C in non-apo B-LP to apo C in apo B-LP has been calculated for both CII and CII (R-CII and R-CIII, respectively). R-CII (0.49 +/- 0.25) and R-CIII (0.84 +/- 0.54) in patients on maintenance dialysis are significantly lower than in the control group (1.14 +/- 0.57 and 1.45 +/- 0.92, respectively), indicating that hypertriglyceridemia in these patients results from a reduced catabolism of triglyceride-rich LP (TGRLP). Patients with coronary artery disease (CAD) show a distribution of C peptides no different from the control group. Analysis of covariance reveals that the patterns of R-CII and R-CIII are not entirely predictable from the serum concentration of triglycerides. This result seems to support the hypothesis that the underlying metabolic defects involving TGRLP in dialysis patients are not the same as those in patients with CAD.

Adult↗

PubMed1993

Local capsular dissection of parotid pleomorphic adenomas.

Local capsular dissection as described by HANCOCK11 for the treatment of parotid pleomorphic adenomas is discussed. The results of 71 primary parotid pleomorphic adenomas are described, including a 5.6% recurrence rate. This method has the advantage that less facial nerve weakness and Frey's syndrome are seen than with superficial or complete parotidectomy. The recurrence rate appeared to be somewhat higher than with most other series.

Adenoma, Pleomorphic↗

PubMed1993

Some informations on dental tissues obtained from observations on a complex odontoma.

Morphological features of enamel and dentine have been studied in a complex odontoma. The enamel had a prismatic structure with an abundant organic matrix in the inner part and a laminar stratified pattern at the surface. A cell layer above the enamel had the characteristics of maturation ameloblasts. Dentine had morphological characteristics of a normally developed tissue. One of the aggregates forming the odontoma had a structure similar to a normal tooth but the pulp-dentine complex was lacking in the odontoblast cell layer. The loose pulpal tissue of this structure was also devoid of blood vessels and nervous structures.

Adolescent↗

PubMed1993

Observations on the enamel of odontomas.

The morphological study of odontomas provides an alternative model for observing the formation of dental tissues, since different maturing stages are present simultaneously. Investigations were performed on decalcified samples (using light microscopy and transmission electron microscopy) and on undecalcified samples of complex odontoma enamel (using transmission electron microscopy). Simultaneous presence of prismatic enamel at various maturing stages with different structural characteristics was observed. Such enamel was sometimes associated with layers of ameloblastic cells with characteristics of cells in functional activity. In other sites, the enamel did not present a prismatic structure but it appeared as unstructured material clusters with abundant organic component. It was concluded that the theory according to which an ecto-mesenchymal inductive failure occurs in odontomas is not confirmed. The defect seen at the beginning of the differentiated and anomalous tissue maturation may be related to latest events in the development of the enamel organ. In this regard, it was concluded that such events involve the efficiency of the ameloblasts and the possible alterations in the organic matrix.

Adolescent↗

PubMed1992

Lymphatic vessels of the human dental pulp in different conditions.

The characteristics of the lymphatic vessel endothelial wall have been investigated in human normal and inflamed dental pulps. In normal pulps the endothelial wall is characterized by the presence of micropinocytotic vesicles and intraparietal channels. In the inflamed pulpal tissue, where an increase in interstitial fluid pressure occurs, the distended endothelial wall presents open junctions between endothelial cells and the openings of the intraparietal channels. Moreover the micropinocytotic vesicles disappear. The cytoplasm of the endothelial cells is characterized by the presence of numerous Weibel-Palade bodies, which increase in number in the dilated vessels. In the fibrillar apparatus surrounding the lymphatic vessel wall collagen fibrils are the prevalent component, while elastic fibers are not present. The different morphological properties of the lymphatic vessels are compared and discussed with regard to the variation of the functional conditions of the tissue.

Adult↗

PubMed1992

Dermal lymphatics in myotonic dystrophy.

Myotonic dystrophy is an hereditary disorder of several organ systems. Skeletal muscle is a principal target organ, but abnormalities also occur in the peripheral microcirculation. Because morphological and functional changes in the dermal blood microcirculation may affect interstitial fluid drainage of the skin, we examined dermal lymphatic morphology in adult patients with myotonic dystrophy. Skin biopsies were taken from the big toe from patients with myotonic dystrophy (age 18-50 years) and subjected to light and electron microscopy; five healthy subjects served as controls. The salient findings in myotonic dystrophy were ultrastructural changes of the lymphatic endothelial cells and the fibrillar elements that surround the lymphatic wall. These abnormal lymphatic findings are interpreted in light of changes in the blood microvasculature and loose connective tissue in this disorder.

Adolescent↗

PubMed1991

The Istituto Rizzoli-Beretta experience with osteosarcoma of the jaw.

Twenty-eight osteosarcomas (OS) of the jaw were reported. There were 15 male and 13 female patients (age range, 9 to 68 years; mean, 36.9 years); 57.1% of the patients were older than 30 years of age. Swelling was the most frequent symptom; it was reported on an average of 6 months before diagnosis. Most of the tumors of the maxilla (eight patients) occurred in the alveolar ridge (six of eight). In the mandible (20 patients), the body was the preferred site (11 of 20). Radiographically most of the lesions were either lytic and sclerotic or only lytic. Histologically, 12 cases (42.9%) were osteoblastic osteosarcoma, ten (35.8%) were chondroblastic, four (14.3%) were fibroblastic, and two (7%) were round cell OS. Of the 28 cases, three (10.7%) were low grade, and 25 (89.3%) were high grade. Thirteen patients had intralesional surgery, and 13 had marginal surgery as their initial treatment. Recurrence was the rule in the first group, and it was 69% in the second group. Twenty patients (71%) died, and eight are alive. Of these, two are alive with disease. In the six patients who are alive and disease-free, all but one had marginal to wide surgical margins at the time of the first procedure or wide margins at the time of the recurrences along with chemotherapy or radiation therapy. In the patient in which the surgical margins were marginal, the lesion was small 2.5 X 2 cm. This patient was alive without evidence of disease after 9 years of follow-up.

Adolescent↗

PubMed1991

[Dental tissue-composite bonding. SEM study].

The Authors investigated the different operative methods effects in the transition zone between human fresh teeth calcified tissues and a composite material. Morphological observations, done by means of standard and back scattered scanning electron microscopy, demonstrated the Gluma adhesion system efficiency towards enamel and dentin if manufacturing's applying systems are carefully followed, by showing a structure with no solutions of continuity between tooth and restoration.

Composite Resins↗

PubMed1991

Development of a second generation stereotactic apparatus for linear accelerator radiosurgery.

Linear accelerator radiosurgery technique is based on a multiple intersecting arc irradiations procedure. The coincidence of the axis of two rotation movements (of gantry and treatment couch) into the isocenter is critical for focusing irradiation. In October 1989, our linear accelerator was changed and the stereotactic apparatus had to be adapted to the new machine. After multiple mechanical tests of the new machine, the stereotactic head frame was fixed to the roller bearing allowing rotation of the couch. The new apparatus is described.

Humans↗

PubMed1991

Immunohistochemical localization of endothelin-like immunoreactivity in human tooth germ and mature dental pulp.

The distribution in oral tissues of endothelin, a multifunctional peptide originally identified within endothelial cells, and subsequently in some epithelial cells, neurons and neuroendocrine cells, has not been investigated yet. We have studied the localization of endothelin-like immunoreactivity in human tooth germ and mature dental pulp by immunohistochemical techniques. Such immunoreactivity was detected only within endothelial cells in both mature dental pulp and developing tooth. Arteries and veins of various sizes as well as small thin vessels displayed endothelin-like immunoreactivity. In the tooth germ, the cells of the enamel organ or the precursors of the odontoblasts were found unreactive. In the mature pulp, no cells of the stroma or nerves displayed endothelin-like immunoreactivity. These findings suggest that vascular endothelium may be the only source of endothelin in human dental tissues. It is tentatively proposed that endothelin released in mature tooth pulp may participate in the regulation of the pulpal blood flow. Although the possible role of endothelin in developing tissues is far from being clear, the mitogenic effects and the proto-oncogenes expression induced by endothelin in some cells raise the possibility that this peptide might also play a role during tooth development.

Adult↗

PubMed1991

A transient outward current dependent on external calcium in rat cerebellar granule cells.

The outward potassium current of rat cerebellar granule cells in culture was studied with the whole-cell patch-clamp method. Two voltage-dependent components were identified: a slow current, resembling the classical delayed rectifier current, and a fast component, similar to an IA-type current. The slow current was insensitive to 4-aminopyridine and independent of external Ca2+, but significantly inhibited by 3 mM tetraethylammonium. The fast current was depressed by external 4-aminopyridine, with an ED50 = 0.7 mM, and it was abolished by removal of divalent cations from the external medium. The sensitivity of the transient outward current to different divalent cations was investigated by equimolar substitution of Ca2+, Mn2+ and Mg2+. In 2.8 mM Mn2+, the transient potassium conductance was comparable to that in 2.8 mM Ca2+, while in 2.8 mM Mg2+ the transient component was drastically reduced, as in the absence of any divalent cations. However, when Ca2+ was present, Mg2+ up to 5 mM had no effect. The transient current increased with increasing concentrations of external Ca2+, [Ca2+]o, and the maximum conductance vs. [Ca2+]o curve could be approximated by a one-site model. In addition, the current recorded with 5.5 mM BAPTA in the intracellular solution was not different from that recorded in the absence of any Ca2+ buffer. These results suggest that divalent cations modulate the potassium channel interacting with a site on the external side of the cell membrane.

Animals↗

PubMed1991

Right-sided anarchic (alien) hand: a longitudinal study.

A patient with a bilateral frontal vascular lesion, encroaching upon the mesial cortex on the left and damage of the corpus callosum showed the 'alien hand' phenomenon on the right. The various hypotheses as to the nature of the lesion for the alien hand phenomenon to appear are discussed. It is proposed that an acute clinical condition, following a lesion of the corpus callosum only, should be differentiated from a chronic condition resulting from the additional fronto-mesial lesion.

Arm↗

PubMed1991

Voltage-dependent calcium currents in dissociated granule cells from rat cerebellum.

Voltage-dependent calcium currents were investigated by the patch-clamp technique in whole-cell recording configuration in cultures from 8-day-old rat cerebella, which contained greater than or equal to 90% granule cells. In solutions designed to minimize the sodium and potassium conductances and in 20 mM barium, an inward current activated around -25 mV, reached a peak amplitude at +20 mV and reversed around +80 mV. In 20 mM calcium, this current was approximately 50% of that in barium. From one to three days in vitro only 16% of the cells tested (n = 20) had a current exceeding 50 pA in maximum amplitude, while after four days in vitro the current reached 100 pA in all neurons tested (n greater than 70). Verapamil (50-100 microM) reversibly depressed this current. The dihydropyridine agonist Bay K 8644 (1 microM) enhanced the maximum conductance by 25 +/- 8% (n = 4), caused a negative shift in the activation of 21 +/- 5 mV and a prolongation of the deactivation time course as the voltage was stepped back from +20 to -80 mV. The GABAB agonist baclofen (50 microM) reversibly depressed the current by 27 +/- 8% in 80% of the cells. The effect was similar to that of GABA (10 microM), when the GABAA response (chloride current) was partially blocked by bicucculine. This current can be classified as a dihydropyridine-sensitive high-voltage-activated calcium current. The modulation by GABAB agonists is likely to be significant for presynaptic inhibition.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗