PubMed Health⌕ Search

Biomedical subjects

M Toscano

Publications and source records attributed to M Toscano.

At least 19 recordsLinked to original sources
PubMed1997

Characterization of the hyperpolarization-activated current, I(f), in ventricular myocytes from human failing heart.

BACKGROUND: Disease-associated electrophysiological alterations may contribute to the increased predisposition to arrhythmias of the hypertrophied or failing myocardium. An I(f)-like current is expressed in rat left ventricular myocytes (LVMs), its amplitude being linearly related to the severity of cardiac hypertrophy. Here, we report the occurrence and electrophysiological properties of I(f) in human LVMs. METHODS AND RESULTS: LVMs were isolated from hearts of three male patients undergoing cardiac transplantation for terminal heart failure due to ischemic dilated cardiomyopathy. The patch-clamp technique was used to record I(f), ie, a barium-insensitive, cesium-sensitive, time-dependent increasing inward current elicited on hyperpolarization. Membrane capacitance was 244 +/- 27 pF (n = 25). I(f) occurred in all cells tested; its density measured at -120 mV was 2.1 +/- 0.3 pA/pF. Activation curves of I(f) (n = 24) were fitted by a Boltzmann function; the threshold was -55 mV; midpoint, -70.9 +/- 2.1 mV; slope, -5.4 +/- 0.3 mV; and maximal specific conductance, 19.6 +/- 2.5 pS/pF. I(f) blockade by extracellular cesium was voltage dependent. Reducing extracellular potassium concentration from 25 to 5.4 mmol/L caused a shift of the reversal potential from -12.7 +/- 0.5 to -24.8 +/- 2.1 mV and a 64% decrease of current conductance. CONCLUSIONS: I(f) is present in human LVMs. Its electrophysiological characteristics resemble those previously described in hypertrophied rat LVMs and suggest that I(f) could be an arrhythmogenic mechanism in patients with severe heart failure.

Cardiac Output, Low↗
PubMed1996

Video-assisted minimally invasive coronary operations without cardiopulmonary bypass: a multicenter study.

OBJECTIVE: The need to avoid the risks associated with cardiopulmonary bypass has led to the interest in coronary operations without cardiopulmonary bypass. PATIENTS AND METHODS: From April 1994 to September 1995, 44 patients (mean age 63.3 +/- 10.0 years, range 43 to 83 years) were selected for video-assisted coronary artery bypass grafting without cardiopulmonary bypass through a small anterior thoracotomy. Mean preoperative ejection fraction was 50.7% +/- 13.4% (range 20% to 65%). Four patients had left ventricular dysfunction (ejection fraction below 35%). Thirty patients had stable angina (26 with class 3 angina) and 14 had unstable angina. One had recurrent angina (redo). In all cases a small (3.5 to 11 cm) anterior thoracotomy (43 left and one right) was performed and the harvesting of the left internal thoracic artery was video-assisted by thoracoscopy. RESULTS: The left internal thoracic artery was used in 43 cases to graft the left anterior descending coronary artery; the right thoracic mammary was used in one case to graft the right coronary artery; the radial artery was used in one case to perform a T-graft to the first diagonal and first marginal branches. We recorded one death (2.3%) and one case of postoperative low cardiac output syndrome (2.3%). Perioperative myocardial infarction occurred in two cases (4.5%). We did not record noncardiac complications (cerebrovascular complications, kidney failure, prolonged ventilatory support, or wound complications). Supraventricular and ventricular arrhythmias were never detected. CONCLUSION: According to our experience, video-assisted coronary bypass through a small anterior thoracotomy is a new promising technique that can be considered an alternative in most cases to angioplasty and complementary to conventional coronary operations.

Adult↗
PubMed1996

Total arterial myocardial revascularization without cardiopulmonary bypass.

The risks associated with cardiopulmonary bypass have led to an interest in coronary surgery without the use of such a bypass. Six patients of mean(s.d.) age 62.0(8.0) (range 52-71) years were selected for elective coronary surgery without cardiopulmonary bypass. In five cases a midline sternotomy and in one case a small anterolateral thoracotomy were performed; in the latter case the harvesting of the proximal end of the left internal mammary artery was video-assisted by thoracoscopy. The left internal mammary artery was used in all cases; the right internal mammary artery was used in one case, the radial artery in four, the inferior epigastric artery in two and the right gastroepiploic artery inn one. No patient died or had a stroke. There were no postoperative episodes of low cardiac output syndrome or perioperative myocardial infarction. All patients were extubated within a few hours after surgery. The mean(s.d.) intensive care unit and hospital stays were 1.3(0.5) and 5.0(0.9) days, respectively. Total arterial myocardial revascularization without cardiopulmonary bypass using composite grafts, is a new and promising technique that is feasible with low risks and good early results in selected cases.

Aged↗
PubMed1996

Arterial myocardial revascularization without cardiopulmonary bypass through a small thoracotomy.

The opportunity to obviate the risks associated with cardiopulmonary bypass (CPB) while maintaining the long-term survival previously demonstrated with the use of arterial grafts, led us to perform myocardial arterial revascularization without CPB, using a small left thoracotomy as the surgical approach. One patient was operated on with this technique grafting the left anterior descending artery with the left internal mammary artery and grafting sequentially the first diagonal branch and the first marginal branch with a T-graft of radial artery. A small anterolateral thoracotomy was performed and the proximal harvesting of the left internal mammary artery was video-assisted by thoracoscopy. No hemodynamic deterioration occurred during the procedure. The patient was discharged on postoperative day 5 and the postoperative course was uneventful.

Aged↗
PubMed1995

In vitro cytokine production and T-cell proliferation in patients undergoing cardiopulmonary by-pass.

Cardiac surgery, employing cardiopulmonary by-pass (CPB), has long been associated with a generalized immunosuppression. To further understand the complex physiological and immunological changes related to CPB, we decided to investigate whether CPB affects the immune response, with regard to T-cell activation and cytokine production. Using phytohaemagglutinin (PHA) as mitogen and peripheral blood mononuclear cells (PBMC) isolated from patients undergoing CPB, we investigated whether this procedure has any effect on interferon-gamma(IFN-gamma) and other cytokine production and/or PBMC proliferation. Comparisons were made between the responsiveness of PBMC obtained before, during and at the end of CPB. In all patients, CPB significantly reduces IFN-gamma and interleukin 2 (IL-2) production in response to PHA. On the other hand, tumour necrosis factor-alpha (TNF-alpha) production was also significantly diminished, while interleukin 6 (IL-6), interleukin 1 beta (IL-1 beta) and interleukin 8 (IL-8) release in response to PHA was not significantly affected. Reduced IFN-gamma, IL-2 and TNF-alpha production was associated with a significant decrease in PBMC proliferation. These results might be related to the mechanical damage on blood cells described during extracorporeal circulation procedures as well as the release of immunosuppressive factors during surgery. The immunosuppression observed during CPB may play an important role in the development of infectious complications after CPB.

Cardiopulmonary Bypass↗
PubMed1995

Warm heart surgery eliminates diaphragmatic paralysis.

Since January 1992, we adopted a new method of myocardial protection: warm blood cardioplegia with continuous ante-retrograde combined delivery during normothermic cardiopulmonary bypass, (CPB) instead of cold blood intermittent cardioplegia plus topical ice slush in hypothermic CPB. We have compared postoperative chest X-rays of 50 patients who underwent elective coronary artery bypass with normothermic CPB to postoperative chest X-rays, of 50 patients operated upon with hypothermia. In the cold group transitory diaphragmatic paralysis, as well as pleural effusions and thoracentesis related to the hypothermia, and topical cooling, were statistically increased over that of warm group. The data suggest that topical cooling with slush ice is responsible for phrenic nerve injury and that warm heart surgery has no associated incidence of diaphragmatic injury.

Aged↗
PubMed1995

Coronary surgery without cardiopulmonary bypass.

The need to obviate the risks associated with cardiopulmonary bypass (CPB) in coronary surgery has led to an interest in coronary artery bypass grafting without CPB. From November 1994 to May 1995, 58 patients (49 males and 9 females, mean age 61.8 +/- 9.3 years, range 40-74) were selected for coronary artery bypass grafting without CPB. Three patients had left main stenosis and 6 had left ventricular dysfunction (ejection fraction < 40%). Stable angina was present in 42 patients (27 with low threshold angina) and unstable angina in 16. In 44 patients a routine median sternotomy and in 14 cases a small anterior thoracotomy were performed: in the latter the proximal harvesting of the left internal mammary artery was video-assisted by thoracoscopy. The left internal mammary artery was used in 53 cases; the saphenous vein was used in 36 cases; the radial artery was used in 4 cases; the inferior epigastric artery was used in 2 cases and the right gastroepiploic artery in 1 case. We recorded 1 death (1.7%) and 1 case of postoperative low cardiac output syndrome requiring counterpulsation (1.7%). Perioperative myocardial infarction occurred in 3 cases (5.8%). We did not record noncardiac complications (cerebrovascular, renal failure, prolonged ventilatory support over 24 hours or sternal wound complications). Supraventricular and ventricular arrhythmias were never detected. Mean intensive care unit and hospital stay were 1.1 +/- 0.5 and 5.1 +/- 1.7 days, respectively. In conclusion, according to our experience, "beating heart" coronary surgery is a new promising technique that can be considered alternative in most cases to percutaneous transluminal coronary angio and complementary to conventional coronary surgery.

Adult↗
PubMed1993

[Immunostimulation in heart surgery: thymostimulin. Preliminary data].

The immunodepressive effect of surgical procedures is well known. Immunotherapy with thymic hormones has used a long time to prevent surgical immunitary damage. In cardiac surgery, we can observe a hard immunitary depression caused by the cardiopulmonary bypass (CBP). In this paper we evaluate the response to immunotherapy, with an extractive thymic hormone: thymostimulin at the dosage of 1 mg/kg/day; 20 patients of a group of 40 underwent CBP. Immunological monitoring was obtained with the "multitest CMI", a disposable skin test to evaluate changes of lymphocytes, especially T cells. Results shows a significant increase of response in patients treated with thymostimulin versus control. A larger sample and a deeper immunitary assessment will be provided in the future.

Adjuvants, Immunologic↗
PubMed1992

[Postendocarditis aneurysm of the right sinus of Valsalva: its echographic diagnosis with preoperative angiographic confirmation].

The sinus of Valsalva aneurysm is a rare complication of bacterial endocarditis in infancy and childhood. This report describes a young man with congenital aortic stenosis and bacterial endocarditis caused by Salmonella typhi. Bacterial endocarditis in this young man was complicated by the development of an aneurysm of the right sinus of Valsalva and a severe aortic regurgitation. Two-dimensional and Doppler echocardiography proved useful for the initial diagnosis and serial follow-up of this unusual disorder. However, an angiographic examination has been necessary for the surgical correction in order to understand the relationship between the aneurysm and the coronary arteries.

Adult↗