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Biomedical subjects

G Noera

Publications and source records attributed to G Noera.

34 records · Page 2Linked to original sources
PubMed1989

Early alteration of bioprosthetic cardiac valves in sheep: influence of the immunological status.

Ten Pericarbon valve bioprostheses were examined after being implanted in tricuspid position in two different groups of animals: group I sheep with increased immunoglobulins, plasma levels, and eosinophilis count of more than 10%, due to parasitic infection, and group II sheep without any parasitic infection, i.e. with normal blood data. The explanted valve follow up was between 60-95 hours in both groups. Microscopic observation of group I valves revealed a massive blood cell (lymphocytes, eosinophilis and large mononuclear cells) infiltration especially around the natural pericardial blood vessels in the region of flexion and attachment. The epipericardial surface was covered by fibrin sheath, and immunofluorescence studies showed a strongly positive reaction for immunoglobulins (IgG and IgE) on leaflet surfaces and lamellar stratification into the fibrosa. Microcalcifications were detected around pericardial blood vessels in the same zones where infiltrated blood cells were found. In group II valves cell infiltration was absent with no signs of calcification and immunofluorescence was negative. Our data suggest that immunoglobulins adherence followed by blood cell infiltration may be one of the early causes of tissue leaflet degeneration and there is a parallel trend between plasma immunoglobulin levels and the early tissue alteration. Our data show that the experimental model for testing bioprostheses in sheep is influenced by the pre-immunological status and it is important to control it before surgery.

Animals↗
PubMed1988

Experimental right ventricular outflow tract reconstruction with a composite Mitrathane monocusp patch: preliminary results.

Twenty large white pigs underwent normothermic right ventricular bypass, pulmonary artery valve excision and right ventricular outflow tract (RVOT) reconstruction using a synthetic material (Mitrathane). The animals were divided in two groups (ten for each group) for the RVOT reconstruction model: Group I with a composite monocusp patch (with a new design geometrically related to pulmonary artery circumference) and Group II without a valve mechanism. Four early postoperative deaths occurred in Group I (unrelated to monocusp patch function) and seven in Group II (due to acute right ventricular failure). Follow up of the six animals of Group I was 600-630 (average 617.5) days and of the three Group II animals was 95-110 (average 101.6) days. In Group I haemodynamic studies showed no significant difference from preoperative values at 5 months while at 20 months there was a moderate valve insufficiency in all animals. In Group II severe right ventricular insufficiency was present in all animals and spontaneous death occurred after about 3 months. In Group I angiographic studies disclosed no evidence of graft calcification or stenosis while in Group II there was a moderate pulmonary trunk dilatation. Post mortem examination showed no signs of degeneration in any graft. Microscopic studies of both groups revealed an acellular layer of fibrin on the external surface and fibrous deposit on the inner part of the suture with the right ventricle. In Group I there were leukocyte and histocyte infiltration of the grafts. In these experiments our synthetic monocusp model showed good function and durability in comparison to a RVOT reconstruction without a valve mechanism.

Animals↗
PubMed1986

[Microscopic analysis of saphenous veins used for aortocoronary bypass].

The Authors describe a study performed on a sample of 88 saphenous veins used as aorto-coronary bypass grafts. The patients underwent surgery in the Department of Cardiovascular Surgery of Ancona from Jan. 1981 to Dec. 1984. The morphological analysis (light and electron microscope) was conducted with a comparative method between two surgical techniques (ST). The first refers (Group I) to 1981-82, the second (Group II) to 1983-84. In Group I the veins were taken with a conventional surgical technique. In Group II the ST was performed using an atraumatic procedure, topic vasodilators, distension of the vein with autologous blood and driving pressure less than 150 mmHg, and storage of the vein in blood at room temperature. The results show that in Group II there is better preservation of the endothelial venous layer. The distending pressure of the venous graft (less than 150 mmHg) and prevention of venous spasm were statistically relevant (p less than 0.05). The AA. conclude that vein graft damage during surgery can be avoided by means of the following procedures: dissection of the vein with atraumatic technique; prevention of venous spasm with topic vasodilators; distension of the vein at pressure less than 150 mmHg.

Coronary Artery Bypass↗
PubMed1985

In vitro computerized evaluation of biological cardiac prosthesis calcification.

The late valvular bioprostheses failure is mainly related to leaflet calcification. This study reports a new approach to testing the biological prostheses calcification applying a computerized technique to x-ray picture. A bovine glutaraldehyde-fixed bioprostheses (BB) was implanted in two sheep in mitral position. The experimental procedure was performed on valves explanted six months after surgery. The BB x-ray pictures were tested by means of a video display computer (VDC) that can process radiographic, photographic or microscopic images and also evaluate the optical density of image quantifiable. The calcification zone assumes different values according to the calcification degree. The VDC can colour the BB x-ray images and display them on monitors (one black and white, one colour) with the colours strictly related to the grey levels of the image.

Animals↗
PubMed1983

[Anastomosis in coronary surgery: technical improvement using a vein-holding instrument].

A vein holder for vascular surgery is described. Distal (direct or sequential) as well as proximal anastomoses in aorto-coronary bypass surgery can be easily performed with that instrument. It minimizes handling of the graft and provides an excellent visualization in placing sutures in half of the circumference at both ends of the venous graft.

Arteriovenous Shunt, Surgical↗
PubMed1983

Autologous monocusp pulmonary valve: preliminary results of a new surgical technique.

A new technique for constructing a pulmonary valve from the wall of the pulmonary artery is described. Hemodynamic studies conducted following this procedure demonstrated no systolic gradient and good diastolic competence. A long-term study of this procedure is needed to determine whether or not the technique has clinical applicability.

Animals↗
PubMed1983

[Emergency surgical treatment of infectious endocarditis. Experience developed on 19 consecutive cases].

Our experience with the emergency surgical treatment of 19 consecutive cases of infective endocarditis (IE) is reported. The aortic valve was always affected, either alone (n = 16) or together with the mitral valve (n = 3). All patients were male. In 10 cases it was possible to identify the infecting agent (a staphylococcus was found in 6). Congestive heart failure (CHF) was the principal indication for surgery in 14 cases (in 6 active IE was associated). Five patients (1 with CHF) underwent operative treatment because of systemic emboli. Fifteen patients were in New York Heart Association (NYHA) functional class IV, 3 in class III and 1 was in class II. Two patients (10.5%), both operated on for CHF, died in the early postoperative period. Early prosthetic valve dehiscence occurred in 2 cases, reoperation was successful in both. Follow-up of operative survivors ranges between 7 and 108 months (mean = 53.24 +/- 41.89). One patients died 10 months after operation with CHF following late prosthetic dehiscence. Out of 16 currently surviving patients 14 are in NHYA functional class I, 1 is in class II and 1 in class III. No one of them has had relapse of IE.

Adolescent↗
PubMed1983

[Coronary spasm following myocardial revascularization. Clinico-therapeutic considerations in a successfully treated case].

A 30-year-old man had a spasm of the anterior descending coronary artery and received a bypass graft. The spasm which caused several cardiac arrests was relieved by intracoronary injection of nitrates and verapamil. The patient was discharged 13 days after surgery, receiving nitrates and calcium antagonists. Four months after operation he remains asymptomatic.

Adult↗
PubMed1982

[Epicardial lipoma. Report of a surgical case and review of the literature].

A case of massive epicardial lipoma in an asymptomatic patient is presented. The diagnosis of solid intrapericardial mass was achieved by two-dimensional echocardiography without cardiac catheterization. The complications of postoperative course, which included myocardial infarction, cerebral embolism, and the patient's late sudden death, suggest that the cardiopulmonary bypass should be used in similar circumstances. Lipomas of the heart should be kept in mind in patients with unexplained enlargement of the cardiac silhouette whenever pericardial effusion and heart disease may be excluded.

Electrocardiography↗