Biomedical subjects

M Vichi

Publications and source records attributed to M Vichi.

9 recordsLinked to original sources

PubMed1992

Increased expression of tissue plasminogen activator and its inhibitor and reduced fibrinolytic potential of human endothelial cells cultured in elevated glucose.

In diabetic patients, elevated plasma levels of t-PA and PAI-1 accompany impaired fibrinolysis. To identify mechanisms for these abnormalities, we examined whether vascular endothelial cells exposed to high glucose upregulate t-PA and PAI-1 production and whether ambient PA activity is decreased concomitantly. In 17 cultures of human umbilical vein endothelial cells grown to confluency in 30 mM glucose, the t-PA antigen released to the medium in 24 h was (median) 52 ng/10(6) cells (range 10-384) and the PAI-1 antigen was 872 ng/10(6) cells (range 217-2074)--both greater (P less than 0.02) than the amounts released by paired control cultures grown in 5 mM glucose--29 ng/10(6) cells (range 7.5-216) and 461 ng/10(6) cells (range 230-3215), respectively. In the presence of high glucose, the steady-state levels of t-PA and PAI-1 mRNAs were increased correspondingly (median 142 and 183% of control, respectively, P less than 0.05); high glucose per se and hypertonicity contributed to the upregulation in additive fashion. The PA activity of conditioned medium from cultures exposed to high glucose was 0.4 IU/ml (range 0.2-0.6), which was significantly lower (P less than 0.02) than the PA activity of control medium (0.5 IU/ml, range 0.2-0.9). No difference was observed when comparing the PA activities of acidified conditioned media, expected to be depleted of inhibitors. Thus, high glucose coordinately upregulates endothelial t-PA and PAI-1 expression through effects exerted at the pretranslational level and enhanced by even mild degrees of hypertonicity.(ABSTRACT TRUNCATED AT 250 WORDS)

Cells, Cultured↗

PubMed1991

[The transmigration of the permanent lower canine].

A rare dental anomaly--the transmigration--is analysed. This condition, which is sparsely recorded in the literature, typically affects the mandibular canine. Twelve cases in which an unerupted mandibular canine has crossed the midline, are described and discussed. Reference is made to considerations put forward in the past by other Authors on this subject, after which personal conclusions are drawn on the diagnosis, etiology and therapy of this rare but serious behaviour of the mandibular canine. The anomaly can be properly diagnosed only by an attentive radiographic evaluation which is primarily based on the orthopantomogram. A series of successive panoramic radiographs taken over years documents the progressive ectopic movement of an unerupted mandibular canine from its developmental site, through the symphysis of the mandible. Lateral, postero-anterior cephalometric films and periapical radiographs, provide additional important information. After having analysed the most frequent etiological factors of mandibular canine impaction, the authors present their considerations concerning the probable pathogenetic mechanism of transmigration. In addition to the proinclination of the lower incisors and the increasing axial inclination of the unerupted canine, already pointed out by other authors, an enlargement of the symphyseal cross-sectional area has been observed and documented. In conclusion it is important, also from a therapeutical point of view, to keep under control, by periodical panoramic radiographs, all those clinical situations considered at risk due to their possible evolution in transmigration and which are characterized by: 1) an unerupted canine which can be palpated in a mesial position in the labial sulcus; 2) an enlarged symphyseal cross-sectional area; 3) an obstacle to normal eruption (cysts, odontomas, ecc.); 4) a proinclination of the lower incisors. A progressive worsening of the position of the unerupted canine should induce to consider the possibility of an early interception of this anomalous condition, which, once established, results in the definitive impaction of the tooth.

Adolescent↗

PubMedDate not supplied

Microscopical aspects of root resorption of human deciduous teeth.

In order to obtain detailed information on the tissue changes which occur during physiological root resorption, 52 human deciduous teeth at various stages of resorption were studied under light microscopy. The early stage of root resorption was defined as resorption of not more than one third of the root length; the late stage was defined as resorption of more than one third. A close topographical interrelationship was found among che sites of pressure of the permanent tooth, the extent of root resorption and the types of tissue changes. Linear resorption (which reflects suspension or marked slowing down of resorption) and redeposition of hard tissue were more pronounced at the early stage of resorption, while lacunar resorption was more pronounced at the late stage. There were pronounced haemorrhagic and inflammatory infiltrates within the pulp at the late stage of resorption and the subodontoblastic cells disappeared as the infiltrates took over the tooth. False denticles were found frequently, especially at the early stage of resorption. Unexpectedly, acellular cementum was found to be deposited against secondary dentine at the cuspidal tip of the pulp chamber of seven teeth, independently of any sign of resorption nearby. These data indicate that: 1) the pressure exerted by a permanent tooth is the most important factor in the differentiation of odontoclasts. 2) the extent of lacunar (i.e., active) resorption correlates directly with the resorption rate, which is higher at the late stage of root resorption. 3) inflammation is a consequence, rather than a cause, of resorption; it may lead to the loss of subodontoblastic cells and a consequent decrease in the ability of the pulp cells to replace damaged odontoblasts. 4) the pulp of the deciduous tooth might be cementogenic in some way, given that about 13% of the samples were found to be so.

Adolescent↗

PubMedDate not supplied

[Cephalometric study of the results of orthodontic treatment of Class III malocclusion].

It's carried out a research on 60 children, 32 boys and 28 girls, taken from 5-12 of age, affected by Class III malocclusion. All of cases was subdivided in four groups on the ground of the age of orthodontic treatment beginning. Two teleradiographs of each patient were examined, one at the beginning and one at the conclusion of the treatment. About the results reported on the boards, were expressed some considerations on the effects of Class III malocclusions treatment as they result at the cephalometric analysis, in comparison with the starting situation of lack of balance. In every case is pointed out the significance of interception and a more favourable behaviour of cephalometric data in the groups with a earlier beginning of treatment.

Cephalometry↗

PubMedDate not supplied