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Biomedical subjects

C Marchetti

Publications and source records attributed to C Marchetti.

At least 55 records · Page 3Linked to original sources
PubMed1997

Early results with the minimally invasive thoracotomy for myocardial revascularization.

OBJECTIVE: We report the early results of the left anterior descending artery revascularization through a minimally invasive thoracotomy, examining the main technical aspects of the operation. METHODS: From January 1995 to September 1996, 51 patients underwent myocardial revascularization through a mini-thoracotomy on beating heart without cardiopulmonary bypass. The main indication to operation was limited lesions of the left anterior descending artery with contra-indications or high risk of failure of angioplasty. The position of the patient was the same than traditional surgery; the chest was opened on the fourth left intercostal space; the left internal mammary artery harvested under direct vision; temporary occlusion of the left anterior descending was obtained prevalently using 5-0 poliypropilene sutures; the anastomosis was performed with single or double 7-0 or 8-0 suture. In six patients the chest was closed and a conventional open-heart operation was performed due to internal mammary artery or left anterior descending unsuitability for minimally invasive revascularization. All the patients were submitted after operation to early angiographic control and/or a Doppler study of the mammary flow. RESULTS: There was no intra-operative mortality. One patient had a postoperative myocardial infarction of the anterior-lateral wall of the left ventricle, and died after an emergency open-heart operation. In one case the patient was reopened after a few hours for a bleeding. Three patients showed various degrees of anastomotic stenosis at the angiographic control. CONCLUSIONS: Several technical difficulties can play an important role in the operative outcome because a single repeated technical error could not fully explain these heterogeneous observed failures. The technique of myocardial revascularization through a left anterior small thoracotomy might present several critical points, particularly: (1) the harvesting of LIMA, meaning the preservation of integrity of the arterial wall and adequacy of the length; (2) the method of the temporary closure of the LAD during of the anastomosis; (3) the stabilization of the LAD and the surgical technique of the anastomosis; (4) the methods for intraoperative control of the patency of the anastomosis. All points mentioned have been thought in our experience to be causes of early failure.

Aged↗
PubMed1997

Synovia hyperplasia and calcification in the human TMJ disk: a clinical, surgical, and histologic study.

The aim of the study was to investigate the morphologic modifications occurring in the synovial tissue after severe derangement of the articular structures with dislocation or perforation of the disks. Light microscopic, ultrastructural, and immunocytochemical investigations were performed on 10 disks. Arthroscopic examinations had documented adhesions between the diskal surfaces and the glenoid eminence or the condylar head in all the selected cases. Histologic examination showed a remarkable hyperplasia of the synovial tissue with the formation of prominent protrusions. An evident increase of type B (fibroblast-like) cells and the presence of cells with the ultrastructural and immunocytochemical characteristics of myofibroblasts were observed. Foci of mineral precipitates and large deposits of calcified tissue were present in the synovial villi in three samples. Our observations suggest that functional failure and morphologic lesions of the synovia may be caused by arthropathy.

Actins↗
PubMed1997

The articular disc surface in different functional conditions of the human temporo-mandibular joint.

The peripheral discal tissue and the surface covering layer have been studied in normal and in variously damaged human temporo-mandibular joint discs. In the normal disc the tissue consisted of dense bundles of fibers and rare fibrocytes. The surface of the disc was covered by a regular basophilic and electron-dense layer. These morphological characteristics persisted also in some pathological discs in which fibrous derangements had already occurred in the deep parts. In very deformed and damaged discs associated with serious functional anomalies, the superficial discal tissue consisted of rare fibers dispersed in a loose ground substance and of an increased number of cells. The superficial coating was formed by an irregular dense lamina and aggregates of various materials containing cellular debris, vesicles, filaments and amorphous components. These deposits are probably due to degeneration processes of discal tissue. This investigation suggests that the superficial discal tissue and the covering layer are together involved in maintaining the functional properties of the articular surfaces. Their structural modification in severe functional anomalies leads to failure in the maintenance of nonadherence conditions and to deterioration of the functional defect.

Actin Cytoskeleton↗
PubMed1997

Accuracy of cholesterol measurements in Italian clinical laboratories. Joint project GISSI prevention--Italian Society of Clinical Biochemistry. SIBioC GISSI Prevenzione Group.

We report the results of an external quality assessment scheme for serum total cholesterol measurement involving about 100 Italian laboratories participating in an epidemiological study of post myocardial infarction. Two frozen human serum pools with Abell-Kendall assigned values are distributed quarterly at the laboratories (up to now seven events occurred); the obtained results are evaluated and discussed. In one exercise (# 5) duplicated measurements were repeated on three different days. Eighty-five to 98% of the laboratories obtained results within the total error limits (+/- 8.9%). But, while precision (calculated on the six replicates of exercise # 5) is good (90% of the laboratories obtained CV < 3%), inaccuracy problems are evident in every event. Indeed the mean bias from the reference method value ranged from 1.54 and 3.49% in the various events.

Analysis of Variance↗
PubMed1997

[Brachytherapy with pulsed dosage. General considerations. Radiobiological considerations. First clinical experience in Mestre (Venice)].

The pulsed dose rate (PDR) brachytherapy technique is analyzed and compared with the low and high dose rate (LDR and HDR, respectively) techniques relative to therapy and management, considering the advantages and pitfalls of each technique. From a radiobiological viewpoint, PDR optimization is aimed at obtaining the same therapeutic results as with LDR and HDR relative to both tumor cell killing and possible late damage. PDR permits to administer the same nominal dose rates as with LDR and HDR, but with very different pulse intervals and length. March, 1995, through March, 1996, forty-two patients were treated with microSelectron PDR at the radiotherapy Department of Umberto I Hospital in Mestre (Venice). Twenty-two patients were irradiated on the vaginal vault, 14 on the anal canal, 4 on the breast, one on the endometrium and one on the urethra (the latter patient was a man). Dose rates were 250-300 cGy/h in the vaginal vault and 90 cGy/h in the other sites. Source-dwell interval in the applicators was 2.5 mm, dwelling time for each position ranged 6.8-122 s, 3-73 pulses were applied lasting 167-1958 s. The unit was reliable and the only problem was the need to recalibrate it every 5-6 applications because of computer memory saturation. Because of the short minimum follow-up (3 months), only the early reactions to treatment have been assessed: no toxicity was found in the vaginal vault, endometrium and breast. Low-grade proctitis was observed in 11 of 14 treated anal canals and another patient complained of more severe symptoms for two weeks; the disease progressed in two anal canal patients, as in the urethra patient. In conclusion, PDR brachytherapy appears a reliable technique whose early clinical results are encouraging.

Brachytherapy↗
PubMed1997

[Axillary lymph node microcalcifications disclosing breast cancer].

Intra nodal calcifications associate with breast cancer are uncommon. The rare publications always describe malignant microcaocifications in axillary lymph nodes, evolving with the primary breast tumor imaged on mammography. In the reported observation, we observed calcified metastatic neoplasm in axillary nodes, preceding the intramammary lesion.

Adult↗
PubMed1997

[Osteo-conductive materials: animal experiments and instrumental analysis II].

BACKGROUND: In daily dental surgery practice, when it is not possible to obtain-enough autogenous bone graft to fill bone defects, bone substitutes can be useful for bone regeneration. MATERIALS AND METHODS: After a preliminary microscopic examination of histologic samples obtained from semithin sections of the tibias of rats showing no major differences in the results both for the single material and implant time, further studies on five different osteoconductive materials used in oral clinical practice were carried out with microradiography, SEM and X-ray microanalysis. In experimental animals (rats) bone defects 3 mm large were surgically induced in both tibias: one of the defects was filled by bone substitutes and on the other side the bone defect healed naturally. RESULTS AND CONCLUSIONS: The findings obtained were studied in depth, and allowed to conclude that the materials tested are suitable for the purpose for which they are marketed. Non-demineralized bovine bone showed the best results with a high degree of osteointegration. However, the results also show that not all the materials tested offer healing advantages over controls.

Animals↗
PubMed1996

Ectocellular in vitro and in vivo metabolism of cADP-ribose in cerebellum.

CD38, a type II transmembrane glycoprotein predominantly expressed in blood cells, is a bifunctional ectoenzyme directly involved in the metabolism of cADP-ribose (cADPR). This is a potent Ca2+ mobilizer in several types of cells. The relationship between the ectocellular site of cADPR production and its intracellular calcium-related functions is poorly understood. Cultured rat cerebellar granule cells showed both enzymic activities of CD38, ADP-ribosyl cyclase and cADPR hydrolase, at a ratio of 16 to 1 respectively, and were immunostained by the anti-(human CD38) monoclonal antibody IB4. In these cells externally added cADPR and beta-NAD+ (the precursor of cADPR), but not alpha-NAD+ or ADP-ribose, enhanced the peak of the depolarization-induced rise in intracellular Ca2+ concentration. This effect was inhibited by 1 microM ryanodine, suggesting a potentiation of calcium-induced calcium release by cADPR. CD38 ectoenzyme activities, ADP-ribosyl cyclase and cADPR hydrolase, were also demonstrated in vivo by microdialysis of adult rat cerebellum, where IB4 bound to granule neurons selectively. Trace amounts (11.5 +/- 3.8 nM) of NAD+ were detected by microdialysis sampling and sensitive assays in the basal interstitial fluid of the cerebellum. These results provide a link between ectocellular cADPR turnover and intracellular calcium mobilization in cerebellum.

ADP-ribosyl Cyclase↗
PubMed1996

High affinity block by nimodipine of the internal calcium elevation in chronically depolarized rat cerebellar granule neurons.

Chronic depolarization enhances survival of cultured rat cerebellar granule neurons by elevating the internal calcium concentration ([Ca2+]i). In Fura2-loaded cells maintained in 25 mM KCl, [Ca2+]i was close to 150 nM and decreased to approximately 50 nM when KCl was lowered to 5.4 mM. The effect of nimodipine (IC50 = 0.45 nM) was similar to depolarization removal, while agatoxin IVA (up to 500 nM) was ineffective. In whole-cell-clamp experiments, the IC50 for current inhibition was 57 nM, while with transient, KCl-induced depolarizations, the dose dependence of nimodipine inhibition had a 'double-affinity' shape, with IC50(1) = 0.30 nM and IC50(2) = 71 nM. We concluded that L-type calcium channels are the main responsible of the elevated internal calcium level necessary for survival in these neurons. These channels do not inactivate and bind nimodipine with different affinity, depending on their state.

Animals↗
PubMed1996

Dexamethasone modulates CD2 expression.

Glucocorticoid hormones (GCs) are able to modulate leukocyte activity. We studied the effect of dexamethasone (DEX) on the expression of CD2, an adhesion molecule involved in T-lymphocyte homing and activation. Results of flow cytometry analysis and immunoprecipitation with anti-CD2 monoclonal antibodies (mAbs) indicated that in vitro treatment with DEX augments CD2 expression in transformed T-cell lines. This effect correlated with a rapid increase in the mRNA and was inhibited by actinomycin-D (AD). The DEX-induced CD2 augmentation was transient, peaked at days 1-2 and returned to the levels of untreated controls at days 3-4. It was a dose-dependent phenomenon, mediated by the GC receptor (GCR), because it was inhibited by the GCR antagonist RU486, and was not induced by other steroids such as testosterone and progesterone. This CD2 modulation could presumably contribute to GC-induced effects on T-cell activity.

Animals↗
PubMed1996

Granular cell ameloblastoma. An immunocytochemical study.

Granular cell ameloblastoma is characterized by nests of large, eosinophilic granular cells. These latter have long been the subject of debate. Two cases of granular cell ameloblastomas have been immunocytochemically stained with a panel of antibodies against human mitochondria, S-100 protein, CD 68, low molecular weight cytokeratins, chromogranin, laminin, vimentin, PCNA, bcl-2 and p-53. Granular cells exhibited a membranous positivity with cytokeratins while the non granular cells of the same tumors showed a diffuse cytoplasmic reactivity. Moreover, granular cells showed marked cytoplasmic positivity with CD68 antiserum only while human mitochondria, as well as S-100 protein antisera, were consistently negative. PCNA, bcl-2 and p-53 did not stain the granular cells. These results allow easy distinction of granular cell ameloblastomas from similar tumors exhibiting granular cell changes and indicate that the granularity in ameloblastoma cells is consequent to lysosomal overload.

Adult↗
PubMed1996

Ameloblastic fibroma: a follow-up of six cases.

Six cases of ameloblastic fibroma of the jaw are reported, and the radiographic and histologic features and clinical symptoms are described. A conservative surgical approach, including enucleation and mechanical curettage of the surrounding bone, appeared to be successful for these patients.

Adult↗
PubMed1996

DNA ploidy analysis of squamous cell carcinomas of the oral and maxillofacial region: clinical and pathologic correlations.

DNA ploidy was investigated in 61 specimens obtained from 25 patients with squamous carcinoma of the oral and maxillofacial region. Biopsy specimens of normal tissue surrounding the tumor were also obtained in six patients. Single-cell suspensions for flow cytometric analysis were prepared. The DNA ploidy and histogram were calculated and compared with the histologic grade, presence of lymph node metastases, and course of the disease. The ploidy of the main stemline was peridiploid in 17 carcinomas, hyperdiploid in three, and aneuploid in five. Histologic grade but not nodal involvement was associated with the ploidy of the main stemline. Of 15 multisampled carcinomas 13 showed constant DNA ploidy and histogram classification. In the other two major changes in DNA ploidy (from peridiploid to hyperdiploid in the first and from peridiploid to aneuploid in the second) were found. Survival information was available for 24 patients. Ploidy values higher or lower than 2.5 c were strongly predictive of both overall (p < 0.001) and relapse-free survival (p < 0.001). The lymph node status proved a powerful prognostic indicator (p = 0.014) but was not related to the relapse-free time of survival. Multiparametric evaluation of survival revealed an independent role of both DNA ploidy and nodal involvement in the prognosis of squamous carcinoma of the oral and maxillofacial region.

Adult↗
PubMed1996

P-selectin and von Willebrand factor in bovine mesenteric lymphatics: an immunofluorescent study.

P-selectin (PADGEM, GMP-140, CD62) is an integral membrane protein specific to alpha granules of platelets and Weibel-Palade bodies of blood vascular endothelial cells. The presence in lymphatic endothelial cells of numerous Weibel-Palade bodies and their positivity to immunocytochemical reaction for von Willebrand factor have previously been characterized and described. Because von Willebrand factor and P-selectin codistribute in Weibel-Palade bodies of blood vascular endothelial cells we investigated the presence of both P-selectin and von Willebrand factor in lymphatic endothelium. Lymphatic vessels expressed positive reaction to immunocytochemical assay thereby demonstrating the presence of P-selectin in the endothelium. Distribution and intensity of the reaction were similar to those observed in bovine blood vascular endothelium.

Animals↗
PubMed1996

Structure of the lymphatic microcirculation in the human urinary bladder with different intraluminal pressure and distension.

The localization, morphology and fine structure of initial lymphatic vessels in the mucosa of the empty and distended urinary bladder were studied. Endoscopic transurethral biopsies of the empty (collapsed) bladder showed under light and electron microscopy numerous intramural lymphatics with a dilated lumen and thin profile. Contacts between endothelial cells were single, overlapping, interlocking, and open while the perivascular connective tissue was filled by fascicles of collagen fibers. In the most superficial layer (subepithelial mucosa), lymphatics were not seen. Biopsies obtained under elevated intraluminal pressure and distension showed on light and electron microscopy lymphatic vessels with small lumens characteristically reduced to irregular slits. Endothelial cell contacts were simple or overlapping; open junctions were rare. The perivascular connective tissue was dense and collagen and elastic fibers often abutted one another. These findings support that with a distended or expanded urinary bladder, the effect of increased intraluminal pressure on the superficial (mucosal) layer radially pulls on the connective tissue that in turn compresses the initial lymphatics thereby restricting lymph transport.

Adult↗
PubMed1996

Structure of the initial lymphatics of the human urinary bladder with invasive urothelial tumors.

The ability of urothelial tumors of the urinary bladder to metastasize via the lymphatic circulation and the extent of metastatic involvement of regional lymph nodes is an important parameter in the staging and prognosis of these neoplasms. Accordingly, we examined the site and morphology of initial lymphatic vessels in the mucosa of the human urinary bladder in patients with invasive transitional cell carcinoma. Lymphatics in the papillary tumoral mass was also examined. Endoscopic transurethral biopsies from the urinary bladder of 120 patients with invasive transitional cell papillary carcinoma were utilized for this study. Biopsy from the uninvolved lateral wall of the same patient was utilized as a control. On histopathology of biopsies of neoplastic tissues, initial lymph vessels were seen in the deeper region of the mucosa but not in the subepithelial layer nor in the stroma of the tumoral papillae. The latter were often associated with arteriolar and venular vessels. When edema and inflammation occurred in peritumoral regions, lymphatics showed a dilated lumen, non-indented wall with dissociated perivascular collagen and elastic fibers. Tumoral permeation or embolization of lymphatics was seen in 12% of patients with invasive tumors, and these lymphatic vessels did not display significant morphologic changes. The absence of initial lymphatics in the stroma of tumoral papillae and in infiltrated subepithelial regions of the urinary bladder may explain the absence of lymph node metastasis in early-stage invasive urothelial tumors.

Adult↗
PubMed1996

Craniofacial fibrous dysplasia and Ollier's disease: combined transfrontal and transfacial resection using the nasal-cheek flap.

Fibrous dysplasia and Ollier's disease (skeletal chondromatosis) are bone lesions that result from disorders occurring during ossification. Here we report on a patient suffering from Ollier's disease in whom polyostotic fibrous dysplasia was detected. The main problem for this 20-year-old man was a nasoethmoidorbital cartilaginous mass causing nasal obstruction, nonreducible eye proptosis, and sleep apnea. The lesion was approached by means of a combined route, ie, transfrontally and transfacially (nasal-cheek flap). The possible pathogenetic links existing between the two lesions and the problems involved in surgical treatment are discussed.

Adult↗