PubMed Health⌕ Search

Biomedical subjects

G Possati

Publications and source records attributed to G Possati.

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

Time dependence of endothelium-mediated vasodilation by intermittent antegrade warm blood cardioplegia.

BACKGROUND: The technique of intermittent antegrade warm blood cardioplegia (IAWBC) exposes the heart to brief periods of normothermic ischemia. This may impair endothelial function in coronary arteries. METHODS: Three cardioplegic technique were tested in porcine hearts arrested for 32 to 36 minutes and reperfused for 30 minutes: IAWBC, antegrade cold blood cardioplegia (ACBC), and antegrade cold crystalloid cardioplegia (ACCC). In the hearts arrested with IAWBC, three different intervals of ischemia were used: three 10-minute intervals (IAWBC1), two 15-minute intervals (IAWBC2), and one 30-minute interval (IAWBC3). Rings from the coronary arteries were used to evaluate in vitro the contractile responses to U46619 and the relaxant responses to bradykinin, A23187, and sodium nitroprusside. RESULTS: All six groups (treatment groups and control group) displayed similar responses to U46619 (30 nmol/L) and nitroprusside. In the IAWBC1, IAWBC2, AND ACBC groups, endothelium-dependent relaxations to bradykinin and A23187 were preserved compared with controls, whereas those of the ACCC and IAWBC3 groups were significantly impaired (bradykinin: control, 8.72 +/- 0.07; IAWBC1, 8.73 +/- 0.03; IAWBC2, 8.65 +/- 0.05; IAWBC3, 8.30 +/- 0.07 [p < 0.05]; ACBC, 8.50 +/- 0.03; ACCC, 8.25 +/- 0.09 [p < 0.05]; A23187: control, 7.07 +/- 0.08; IAWBC1, 7.07 +/- 0.06; IAWBC2, 7.04 +/- 0.03; IAWBC3, 6.64 +/- 0.01 [p < 0.05]; ACBC, 6.80 +/- 0.05; ACCC, 6.60 +/- 0.08 [p < 0.05]; nitroprusside: control, 6.19 +/- 0.1; IAWBC1, 6.19 +/- 0.07; IAWBC2, 6.03 +/- 0.03; IAWBC3, 6.08 +/- 0.05; ACBC, 6.04 +/- 0.2; ACCC, 6.05 +/- 0.03; all values are expressed as the negative logarithm of the concentration producing 50% of the maximal response). CONCLUSIONS: Myocardial preservation with IAWBC with ischemic intervals of 15 minutes or shorter does not alter the endothelium-dependent relaxation to bradykinin or A23187 in porcine coronary arteries, but these responses are significantly impaired by ACCC and IAWBC with an ischemic interval of 30 minutes.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1997

Lesions of the target vessel during minimally invasive myocardial revascularization.

BACKGROUND: Minimally invasive coronary artery bypass grafting has recently been introduced into cardiac surgery. In this report we discuss the incidence of surgically induced distal target vessel stenosis in patients who undergo the minimally invasive coronary artery bypass grafting procedure, which represents a major drawback of the procedure in our experience. METHODS: Doppler evaluation of mammary artery flow was performed postoperatively in all 55 patients who underwent minimally invasive coronary artery bypass grafting at our institution. Angiography was performed in the first 35 consecutive patients for control purposes and in 2 patients who complained of angina recurrence. RESULTS: In 32 of the first 35 consecutive patients, the anastomosis was found to be functioning normally and the distal left anterior descending artery was normal; in the remaining 3 patients we found mammary artery occlusion, anastomotic stenosis, and stenosis of the anastomosis and the distal left anterior descending artery in 1 patient each. A distal left anterior descending artery stenosis was found in the only 2 patients who underwent late angiography. CONCLUSIONS: Surgically induced distal target vessel stenosis represents a major drawback of minimally invasive coronary artery bypass grafting in our experience. Further improvement in the means of achieving coronary artery occlusion, as well as in anticoagulant and antiplatelet therapy, is mandatory before minimally invasive coronary artery bypass grafting can be confidently accepted into clinical practice.

Adult↗
PubMed1997

Contractile reserve of dysfunctional myocardium after revascularization: a dobutamine stress echocardiography study.

OBJECTIVES: We sought to investigate the effects of revascularization on the contractile reserve of dysfunctional myocardium. BACKGROUND: The improvement in dysfunctional but viable myocardium after revascularization is frequently less than expected from the amount of contractile reserve detected on dobutamine stress echocardiography. The fate of the contractile reserve, when it does not result in an adequate contractile recovery, is unknown. METHODS: Basal contraction and contractile reserve of infarct zones were assessed by dobutamine stress echocardiography in 21 postinfarction male patients before and > 3 months after revascularization (30 infarct zones; mean +/- SD left ventricular ejection fraction 35 +/- 8%). An infarct zone wall motion score index (WMSI) was calculated. RESULTS: Before revascularization, contractile reserve was present in 14 infarct zones (12 patients) and absent in 16 (9 patients). After revascularization, ejection fraction increased by 5 +/- 4% (p < 0.01) in patients classified as positive for contractile reserve and remained unchanged in those classified as negative. New York Heart Association classification improved in 58.3% and 22.2% of patients, respectively. Basal contraction improved in eight zones with previous contractile reserve (57.1%) and in one zone without (6.3%) (p < 0.01). Contractile reserve was still evident in 13 zones with previous contractile reserve (93%; 8 with contractile recovery), and it developed in 6 zones without (38%; none with contractile recovery). WMSI values after revascularization were decreased from values before revascularization during low dose dobutamine in zones with and without previous contractile reserve (p < 0.01 and < 0.05, respectively). CONCLUSIONS: After revascularization, contractile reserve is maintained or even increases in viable infarct zones that do not recover as expected. It may also develop in some infarct zones judged not to be viable before revascularization. This increased contractile reserve may play a role in the functional improvement of patients after revascularization.

Aged↗
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

A pump-prime aprotinin dose in cardiac surgery: appraisal of its effects on the hemostatic system.

OBJECTIVES: To examine pump-prime aprotinin action on coagulation and fibrinolysis in patients undergoing primary coronary revascularization. DESIGN: A prospective randomized study. SETTING: A university hospital. PARTICIPANTS: Forty-three patients were randomly assigned to either group A, 21 patients treated with 2 x 10(6) kallikrein inhibitor units (KIU) of aprotinin in the cardiopulmonary bypass (CPB) prime, or group B, 22 patients, untreated. INTERVENTIONS: Patients, scheduled for elective coronary surgery, were treated with 2 x 10(6) KIU of aprotinin in the CPB prime. Markers of coagulation and fibrinolysis were evaluated. MEASUREMENTS AND MAIN RESULTS: Surgical times, number of reopenings, and allogeneic blood requirements were collected for each patient. Blood samples were obtained before and after surgery for assessing coagulation (prothrombin time [PT], activated partial thromboplastin time [aPTT], ethanol test, factor VII, antithrombin III [AT III], thrombin-antithrombin III complex [TAT], fragment 1.2 of prothrombin [F1.2]) and fibrinolysis (fibrin degradation products [FOP], plasmin-antiplasmin complexes [PAP], D-dimers) markers variations. In group A surgical times were faster, there were fewer reopenings (0 v 3), and fewer blood transfusions (1 patient v 4 patients). The two groups did not differ for PT, aPTT, and fibrinogen measurements. Postoperative FDP (measurable in more patients of group B at the end of the operation), PAP, and D-dimers postoperatory levels (less increased in aprotinin group) show the antifibrinolytic properties of the drug. Regarding the coagulation markers, factor VII decreased, whereas TAT and F1.2 increased, all to a lesser extent in the aprotinin group compared with the untreated patients, at the end of operation. CONCLUSION: Pump-prime aprotinin minimized, even if not completely inhibited, the activation of coagulation and fibrinolysis during CPB, possibly ensuring a less complicated and safer postoperative recovery. It seemed to allow the maintenance of a correct balance of hemostatic systems, avoiding the risk of thrombotic phenomena.

Adult↗
PubMed1997

The use of mechanical prostheses in native aortic valve endocarditis.

BACKGROUND AND AIMS OF THE STUDY: The optimal aortic valve substitute in cases of active native valve endocarditis (NVE) remains controversial. This report summarizes our experience with the surgical treatment of active aortic NVE using only mechanical prostheses. METHODS: Between January 1988 and January 1996, 20 patients underwent aortic valve replacement for active NVE. There were 17 men and three women. Mean age was 46.5 years (range eight to 63 years). Thirteen patients were in NYHA class IV and seven in class V. Streptococci were isolated in eight cases, while no causative micro-organism could be identified in seven patients. All operations were performed on urgent (n = 13) or emergency (n = 7) bases. A mechanical valve was implanted in all cases and radical resection of the infected tissues performed using different techniques. All patients were followed up at our institution. Two-dimensional color Doppler studies were performed one month after surgery and at six-month intervals after the first year. Transesophageal echocardiography (TEE) was performed at discharge, six months after surgery and yearly thereafter. RESULTS: No patient died in hospital. Mean follow up was 30.5 months, during which time three patients died, though none from endocarditis-related causes. Endocarditis recurred only one (5%). TEE demonstrated a normally functioning aortic prosthesis in 15 cases and trivial paravalvular leakage in two. CONCLUSIONS: Mechanical prostheses represent a safe aortic valve substitute in cases of acute native valve endocarditis. When radical resection of all the infected areas is performed, the incidence of endocarditis recurrence is acceptable. The concept that homografts are the valve substitute of choice in endocarditis cases cannot be supported by this study.

Adolescent↗
PubMed1997

[Minithoracotomy myocardial revascularization: results of early angiographic control].

AIM OF THE STUDY: Minimally invasive direct coronary artery by-pass (MIDCAB) has been proposed as an alternative technical solution in different clinical settings. However, a systematic angiographic study of the results obtained using this new technique has not been published yet. This paper summarizes our preliminary angiographic results with MIDCAB. MATERIALS AND METHODS: From January 1995 to January 1997, 56 patients underwent MIDCAB. All patients were followed up regularly and underwent stress myocardial scintigraphy. A postoperative angiographic control was performed in 48 patients (87.2% of the total) at a mean postoperative interval of 1.7 +/- 2 months. RESULTS: One patient died in hospital. Five patients required further surgery using conventional techniques (either surgical or percutaneous). In 41/48 patients (85.4%), the mammary artery graft and the left anterior descending artery (LAD) were normal. In two cases, we found an anastomotic stenosis, in two cases there was a LAD lesion distal to the anastomosis (at the application site of the stay sutures), one case showed an anastomotic stenosis associated with a distal LAD stenosis, one case had a mammary graft occlusion and one case showed a thrombus-like image in the LAD proximal to the anastomosis. CONCLUSION: Systematic angiographic follow-up of MIDCAB patients seems mandatory in order to evaluate the effectiveness of the technical solutions utilized and to optimize various aspects of this new procedure.

Adult↗
PubMed1995

Aortic coarctation, aortic valvular stenosis, and coronary artery disease: combined one-stage surgical therapy operation.

The presentation of simultaneous severe coarctation of the descending aorta and severe aortic valve disease is uncommon. We describe the management of simultaneous association of aortic coarctation, aortic valve disease, and ischemic cardiomyopathy and describe a one-stage surgical approach for the correction of all pathologies. After performing the aortic valve replacement and myocardial revascularization, coarctation was solved by means of a prosthesis between the ascending aorta and the abdominal aorta. There were no evidence of myocardial ischemia during exercise testing and the blood pressure is normal.

Aorta, Abdominal↗
PubMed1995

Secondary alcohol metabolites mediate iron delocalization in cytosolic fractions of myocardial biopsies exposed to anticancer anthracyclines. Novel linkage between anthracycline metabolism and iron-induced cardiotoxicity.

The cardiotoxicity of doxorubicin (DOX) and other quinone-containing antitumor anthracyclines has been tentatively attributed to the formation of drug semiquinones which generate superoxide anion and reduce ferritin-bound Fe(III), favoring the release of Fe(II) and its subsequent involvement in free radical reactions. In the present study NADPH- and DOX-supplemented cytosolic fractions from human myocardial biopsies are shown to support a two-step reaction favoring an alternative mechanism of Fe(II) mobilization. The first step is an enzymatic two-electron reduction of the C-13 carbonyl group in the side chain of DOX, yielding a secondary alcohol metabolite which is called doxorubicinol (3.9 +/- 0.4 nmoles/mg protein per 4 h, mean +/- SEM). The second step is a nonenzymatic and superoxide anion-independent redox coupling of a large fraction of doxorubicinol (3.2 +/- 0.4 nmol/mg protein per 4 h) with Fe(III)-binding proteins distinct from ferritin, regenerating stoichiometric amounts of DOX, and mobilizing a twofold excess of Fe(II) ions (6.1 +/- 0.7 nmol/mg protein per 4 h). The formation of secondary alcohol metabolites decreases significantly (Pi < 0.01) when DOX is replaced by less cardiotoxic anthracyclines such as daunorubicin, 4'-epi DOX, and 4-demethoxy daunorubicin (2.1 +/- 0.1, 1.2 +/- 0.2, and 0.6 +/- 0.2 nmol/mg protein per 4 h, respectively). Therefore, daunorubicin, 4'-epi DOX, and 4-demethoxy daunorubicin are significantly (P < 0.01) less effective than DOX in mobilizing Fe(II) (3.5 +/- 0.1, 1.8 +/- 0.2, and 0.9 +/- 0.3 nmol/mg protein per 4 h, respectively). These results highlight the formation of secondary alcohol metabolites and the availability of nonferritin sources of Fe(III) as novel and critical determinants of Fe(II) delocalization and cardiac damage by structurally distinct anthracyclines, thus providing alternative routes to the design of cardioprotectants for anthracycline-treated patients.

Alcohols↗
PubMed1991

Gamete intrafallopian transfer by hysteroscopy as an alternative treatment for infertility.

OBJECTIVE: To evaluate efficacy and safety of the hysteroscopic cannulation by flexible catheter of the fallopian tubes for gamete intrafallopian transfer (GIFT). DESIGN: We studied the pregnancy rate (PR) and the safety of this new technique. SETTING: All patients were enlisted for GIFT at our Reproductive Medicine Unit. PATIENTS: We treated 26 patients whose infertility causes were terminal tubal damage, male factors, unexplained factors, and endometriosis. Patients with uterine tubal ostia unsuitable for gamete transfer or cervical incontinence were not included in the group. INTERVENTIONS: The patients underwent ovulation induction and oocyte retrieval by transvaginal ultrasonically guided puncture. The gamete transfers were carried out by hysteroscopic procedure using a flexible catheter put through the operating channel. MAIN OUTCOME MEASURE: The efficacy was evaluated by the PR (25.9%). RESULTS: Seven clinical pregnancies were obtained, but two patients aborted during the first weeks of pregnancy. No ectopic pregnancies were observed. CONCLUSIONS: Our results indicate that hysteroscopic GIFT is an alternative, safe, effective, and not invasive technique for fertility problems.

Adult↗
PubMed1991

Hysteroscopic gamete intra-fallopian transfer: a good alternative, in selected cases, to laparoscopic intra-fallopian transfer.

Results obtained in two groups of patients treated with gamete intra-Fallopian transfer (GIFT) are reported. Hysteroscopic GIFT was carried out in some cases where general anaesthesia was not advisable or possible, i.e. difficulties in tubal catheterization due to pelvic adhesions, extended distal tubal damage, patients' intolerance, lack of available operating theatre. Ovarian stimulation was started on 131 patients for a total of 147 cycles. Twenty-five cycles were cancelled because of failure of the ovarian response. Either laparoscopic (group 1; 73 patients) or hysteroscopic GIFT (group 2; 50 patients) was performed. In group 1 a mean of 6.8 +/- 3.4 oocytes per cycle were retrieved and a mean of 4.7 +/- 1.3 mature oocytes were transferred. The pregnancy rate was 30.1% per retrieval (22 clinical pregnancies). In group 2, a mean of 5.0 +/- 3.1 oocytes was harvested and 3.9 +/- 2.0 mature oocytes per cycle were transferred. Thirteen clinical pregnancies were achieved (26.5% per cycle) in group 2. Comparing the two groups, the number of recovered and transferred oocytes was significantly lower in hysteroscopic GIFT (P less than 0.05 and P less than 0.001 respectively).

Adult↗
PubMed1991

Comparison between two versus three patches single pulse shock defibrillation in pigs.

The aim of the study was to test the hypothesis that defibrillation with a single pulse shock can be obtained at lower energy using three epicardial patches configuration (one cathode and two anodes) instead of the conventional two patches. The total surface area of the two- and three-patches configuration was the same (10 cm2 vs 9.9 cm2). Epicardial spatial configuration was planned by using a computerized heart model. In ten anesthetized open-chest pigs, ventricular fibrillation was induced by using AC current through the mesh plaque epicardial custom-designed electrodes, and the minimum energy requirement for defibrillation was determined 15 seconds after the onset of stable ventricular fibrillation. Results were as follows (mean +/- standard deviation): Defibrillation Threshold 16 +/- 9 J 9 +/- 5 J P less than 0.01 CONCLUSIONS: three epicardial patches configuration significantly reduces energy requirements for defibrillation compared with two patches when single pulse shock is used.

Animals↗
PubMed1991

[Right accessory pathway simulating a nodo-ventricular pathway: an electrophysiologic study and intraoperative mapping].

We report a case of a patient with episodes of wide QRS tachycardia and syncope. During the electrophysiologic study, a wide QRS tachycardia (200 b/m) with left bundle branch block morphology was reproducibly induced by incremental atrial pacing with progressive shortening of the HV interval and lengthening of the AV interval, suggesting the presence of a nodoventricular accessory pathway (Mahaim fiber). The intraoperative mapping performed during tachycardia showed the earliest ventricular activation to be over the right antero-lateral AV groove, different from the usual epicardial activation previously described. According to the earliest epicardial breakthrough point, we performed an epicardial AV fat pad dissection which produced irreversible disappearance of preexcitation, confirmed at the postoperative electrophysiologic study. No recurrence of tachycardia was observed during a follow-up of 11 months. This case further confirms previous data that the "so-called" Mahaim fibers could be a right accessory pathway with decremental properties.

Adult↗
PubMed1989

Persisting hypereosinophilia and myocardial activity in the fibrotic stage of endomyocardial disease.

An unusual case of endomyocardial fibrosis is reported complicating an idiopathic hypereosinophilic syndrome. Persisting hypereosinophilia, degranulated eosinophils in the blood, and myocardial activity have been found accompanying the fibrotic phase of endomyocardial disease. This occurrence supports the unitarian theory on tropical and temperate endomyocardial disease and suggests in such a condition the use of steroids or cytotoxic drugs in addition to surgery.

Endocardium↗
PubMed1976

Significance of 17alpha OH progesterone assay in the evaluation of ovarian and adrenal function.

Plasma 17alpha OH progesterone was assayed radioimmunologically, using an anti-17-OH-progesterone BSA antiserum as specific binding antigen. The method consisted in extracting steroids with ethyl ether from 1 ml plasm (to which 17alpha OH progesterone-1,2-3H had been added for the assessment of losses); the extract was then submitted to chromatography on a Sephadex LH-20 column, antiserum was added and the free steroid was separated from the bound form by Charcoal-dextran. Average recovery of 17alpha OH progesterone-1,2-3H was 75+/-5%. Minimum sensitivity of the method oscillated about 7-10 pg. MIF (Method Interfering Factors) were evaluated. The method was used for the assay of 17alpha OH progesterone plasma levels during normal menstrual cycles, in women undergoing ovarian stimulation with HMG and HCG in the follicular and luteal phase respectively. Finally, changes of plasma 17alpha OH progesterone levels were assessed during adrenal stimulation and suppression in various stages of the menstrual cycle.

Adrenal Cortex Function Tests↗
PubMed1975

[Effects of L-dopa on FSH and LH secretion in men and women].

The behavior of plasma gonadotropins has been studied in amenorrhoic patients and in men suffering from disorders of spermatogenesis after L-DOPA administration. Neither clinical nor laboratory findings warrant hypotheses apt to interpret the different responses observed after the ingestion of the drug; nevertheless, keeping in mind the results reported in the literature, the relationship between L-DOPA and the hypothalamo-pituitary axis appears to deserve further study with the use of more accurate means of investigation and follow-up of the late effects observed in our research.

Amenorrhea↗