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Biomedical subjects

M Maccherini

Publications and source records attributed to M Maccherini.

At least 37 records · Page 2Linked to original sources
PubMed1998

Myocardial ischemic injury and purine metabolism in patients undergoing coronary artery bypass.

OBJECTIVES: High-energy phosphates and their catabolic products were determined in myocardium during coronary artery bypass surgery with blood cardioplegic reperfusion in order to evaluate the effects of aortic cross-clamping and reoxygenation on myocardial purine metabolism. DESIGN AND METHODS: Transmural left ventricular biopsy specimens were taken with ITu-Cut biopsy needles, before aortic cross-clamping, before cross-clamp removal and after 30' of reperfusion; perchloric extracts of the material were analyzed for nucleotide content by capillary zone electrophoresis (CZE). The CZE procedure used separates the complete spectrum of purine metabolites in myocardial extracts obtained from 0.6-8.6 mg biopsy material. RESULTS: The basal values of ATP/ADP ratio and energy charge were low, IMP content was high. After the ischemic period, ATP levels further decreased and IMP, nucleosides and bases accumulated. After reperfusion, nucleoside and base basal levels, but not energy charge, were restored to some extent. CONCLUSIONS: The study arises the problem of myocardial preservation during heart surgery. In this investigation, capillary electrophoresis was an extremely adaptable technique for the evaluation of ischemic injury and could be useful in studying the effects of cardioplegic solutions.

Aged↗
PubMed1998

Abdominal aortic aneurysms in heart transplanted patients.

OBJECTIVE: In the AA's opinion, the dilatation of the abdominal aorta is not a contraindication to heart transplantation. METHODS AND MATERIALS: From July 1994 to February 1998, 3 out of 80 heart transplanted patients, required a replacement of their abdominal aorta because of an infrarenal aortic aneurysm. The first patient (62 years old) did not have an aneurysm by time of heart transplantation: his aneurysm (5.1 cm wide) was resected 2 years later. The other two patients (m, 44 years old; m, 60 years old) had a dilatation of 3.1 and 3.5 cm of the abdominal aorta by time of cardiac transplantation: 15 months later, the aneurysms measured 5.8 and 7 cm, respectively, and had been resected. Two resections were performed through a retroperitoneal approach. RESULTS: All 3 patients had uneventful postoperative course. CONCLUSION: Before heart transplantation the aorta must be screened for dilatation or aneurysm, which can be enlarged by operation. Such lesions can be operated on, with low risks, and should not be a contraindication to heart transplantation.

Adult↗
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↗
PubMed1997

Reduction of oxidative stress does not affect recovery of myocardial function: warm continuous versus cold intermittent blood cardioplegia.

OBJECTIVE: To compare oxidative stress after cardiac surgery in patients treated with two different methods of myocardial protection: warm continuous versus cold intermittent blood cardioplegia. To correlate oxidative stress with postoperative myocardial dysfunction. DESIGN: Prospective, randomised, double blind, trial. SETTING: Institutional centre of cardiovascular surgery. PATIENTS: 20 patients were selected for coronary artery bypass surgery (CABG) on the following basis: stable angina, ejection fraction > 50%, double or triple vessel disease, no previous CABG or associated disease. Patients were randomised to two groups of 10 patients each. INTERVENTIONS: Patients underwent CABG with one of two different methods of myocardial protection and cardiopulmonary bypass. CBC group: intermittent cold blood antegrade-retrograde cardioplegia with moderate hypothermic cardiopulmonary bypass; WBC group: continuous warm blood antegrade-retrograde cardioplegia with mild hypothermic cardiopulmonary bypass. MAIN OUTCOME MEASURE: The index of oxidative stress used was the alteration of whole blood and plasma glutathione redox status. Samples were collected from the coronary sinus and peripheral vein before anaesthesia (T1), before aortic unclamping (T2), 15 minutes (T3), and 30 minutes (T4) after unclamping. Haemodynamic parameters were measured with thermodilution techniques. RESULTS: Oxidised glutathione and glutathione-cysteine mixed disulphide significantly increased in the coronary sinus plasma in the CBC group, and the overall redox balance of glutathione was decreased (P < 0.01) at T2-T4 versus T1, and compared with the WBC group. Comparable results were obtained for coronary sinus blood. There was no correlation between postoperative haemodynamic measurements and oxidative stress markers. CONCLUSIONS: Oxidative stress was significant in patients undergoing CABG using cold blood cardioplegia, while the warm technique minimised the effects of ischaemia. However, oxidative stress was not correlated with myocardial dysfunction following CABG.

Analysis of Variance↗
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

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

Air transport and the fate of pneumothorax in pleural adhesions.

Air travel is contraindicated in patients with a pneumothorax but was necessary because of the exigencies of war in three patients. Three patients with high velocity missile injuries to the chest and pleural adhesions are reported. All had to be evacuated by air, without an intercostal drain or oxygen supplement, from the war stricken area of Northern Somalia (Horn of Africa) to Mogadishu. Two patients with a partial pneumothorax flew on military transport aeroplanes at an altitude of 3000 m in a non-pressurised cabin and recovered rapidly after a few days in hospital. One patient, transported on a small Cessna aeroplane, died after developing bilateral tension pneumothoraces.

Adult↗
PubMed1991

The effect of low-potassium-dextran versus Euro-Collins solution for preservation of isolated type II pneumocytes.

Limited availability of donor organs is a major factor restricting the clinical application of lung transplantation. Improvements in preservation techniques are essential for prolonging storage time and improving lung function following transplantation. The present investigation used primary cultures of adult rat alveolar type II cells as a model for evaluating lung-preservation solutions. Type II cells were plated onto tissue-culture plastic at a density 5 x 10(5) cells/cm2 and maintained in Dulbecco's modified Eagle's medium containing 10% fetal bovine serum (D10) for 40 hr. Cells were then exposed to Euro-Collins solution or a low-potassium-dextran solution (LPD). At designated time points, measurements of lactate-dehydrogenase (LDH) release, protein content, and incorporation of 3H-thymidine into cellular DNA were made. During 12 hr of "storage" at 37 degrees C, cells maintained in LPD released less LDH (14.3 +/- 1.2% of cellular total, mean +/- SEM, n = 5) than their counterparts stored in EC (20.6 +/- 1.6%, P less than 0.05). During the 36 hr following a 6-hr exposure to preservative solutions, LPD-treated cells incorporated more thymidine per mg of protein (2566 +/- 419.8 cpm/micrograms protein, mean +/- SEM, n = 6) compared with cells maintained continuously in D10 (1431 +/- 351, P less than 0.05). By contrast, cells exposed to EC incorporated less thymidine (82.2 +/- 62.8 cpm/micrograms protein) than either cells maintained in LPD or D10 (P less than 0.01 for each comparison). These results suggest that LPD solution is less cytotoxic than EC and that LPD enables higher levels of metabolic activity in recovering epithelial cells. In vitro cultures of type II epithelial cells are a useful model system for the study of lung preservation and posttransplantation lung injury.

Alkaline Phosphatase↗
PubMed1989

Patients with different lung cancers show normal expression of fra(3)(p14.2) in aphidicolin-treated lymphocyte cultures.

Among common fragile sites, fra(3)(p14.2) is the most expressed either spontaneously or after treatment with aphidicolin (APC) in lymphocyte cultures. Because recurrent chromosomal abnormalities involving the short arm of chromosome 3 in tumor tissue are present in various malignancies, including lung cancer, the induction of fra(3)(p14.2) elicited by APC was investigated with the aim of detecting possible interindividual polymorphism in its expression that might be relevant to predisposition toward cancer-related events. Thirty-four patients affected with various lung cancers (14 squamous cell carcinomas, 13 adenocarcinomas, and seven small cell carcinomas) and 14 controls (patients undergoing routine routine follow-up after coronary by-pass) were included in this study. The frequency of fra(3)(p14.2) expression was not significantly different among the patients grouped either by disease or by sex and age. It was estimated that fra(3)(p14.2) accounts for about 20% of total breakage in APC-treated lymphocyte cultures from the general population.

Adenocarcinoma↗
PubMed1989

[CT assessment of encephalic and suprarenal spread of "operable" pulmonary neoplasms. Preliminary results].

Computed Tomography (CT) was employed to evaluate the incidence of brain and adrenal gland metastases in 74 patients (not-small cell lung cancer) staged for surgery. Nine patients presented one or more asymptomatic brain metastases, 4 adenocarcinomas, 3 epidermoid, 2 adenosquamous. In 6 cases adrenal gland masses were found, only one of which was confirmed as a secondary lesion at biopsy. The authors conclude that brain CT is useful in the preoperative staging of lung cancers, independent of the histology of the primary lesion. An accurate assessment of the utility of CT of the adrenal glands requires a larger sample of patients due to the high incidence of benign adrenal gland masses.

Adrenal Gland Neoplasms↗