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Biomedical subjects

M Ricci

Publications and source records attributed to M Ricci.

At least 73 records · Page 4Linked to original sources
PubMed2000

Exposure and mechanical stabilization in off-pump coronary artery bypass grafting via sternotomy.

Although off-pump coronary artery bypass grafting (CABG) is gaining popularity, obtaining exposure and stabilization of coronary arteries located on the lateral and inferior wall of the heart may be problematic. The aim of this study is to describe strategies and techniques of coronary exposure and mechanical stabilization that may be used to achieve total myocardial revascularization of the beating heart.

Coronary Artery Bypass↗
PubMed2000

Study of cosmic rays and light flashes on board Space Station MIR: the SilEye experiment.

The SilEye experiment aims to study the cause and processes related to the anomalous Light Flashes (LF) perceived by astronauts in orbit and their relation with Cosmic Rays. These observations will be also useful in the study of the long duration manned space flight environment. Two PC-driven silicon detector telescopes have been built and placed aboard Space Station MIR. SilEye-1 was launched in 1995 and provided particles track and LF information; the data gathered indicate a linear dependence of FLF(Hz) ( 4 2) 10(3) 5.3 1.7 10(4) Fpart(Hz) if South Atlantic Anomaly fluxes are not included. Even though higher statistic is required, this is an indication that heavy ion interactions with the eye are the main LF cause. To improve quality and quantity of measurements, a second apparatus, SilEye-2, was placed on MIR in 1997, and started work from August 1998. This instrument provides energetic information, which allows nuclear identification in selected energy ranges; we present preliminary measurements of the radiation field inside MIR performed with SilEye-2 detector in June 1998.

Cosmic Radiation↗
PubMed2000

Graft revision after transit time flow measurement in off-pump coronary artery bypass grafting.

OBJECTIVE: To determine whether coronary graft patency can be predicted by transit time flow measurement (TTFM). METHODS: From May 1 1997 to December 31 1998, TTFM was prospectively evaluated in 409 patients undergoing coronary artery bypass grafting (CABG) without cardiopulmonary bypass (CPB). All grafts (1145) were tested with TTFM. RESULTS: Thirty-seven out of 1145 grafts (3.2%) were revised in 33 patients (7.6%). In six cases (18.1%) use of CPB was necessary during revision due to hemodynamic instability. The remaining patients underwent revision off-pump. Thirty-four grafts (91.9%) were revised for both low flow and abnormal flow curve patterns. Findings at revision included: thrombosis of the anastomosis (n=6), stenosis at the toe or heel of the anastomosis (n=8), coronary flap or dissection (n=5), dissection of the internal mammary artery (n=5), graft kinking (n=4), flap at proximal anastomosis (n=1), coronary stenosis distal to the graft (n=3), and no findings (n=2). After revision all flow values and flow patterns improved. Although three additional grafts (8.1%) were revised for low flow (<7 ml/min) despite normal flow patterns, there were no findings at revision and flow values and curves remained unchanged after revision. Postoperatively, one patient developed a stroke (3%), one had an acute myocardial infarction (MI) (3%), one had a sternal wound infection (3%), and one required prolonged ventilatory support (3%). CONCLUSION: Evaluation of TTFM is valuable in determining the status of a coronary graft after CABG. Correct interpretation of flow patterns allows for correction of abnormalities prior to chest closure.

Cardiopulmonary Bypass↗
PubMed2000

Graft patency verification in coronary artery bypass grafting: principles and clinical applications of transit time flow measurement.

The increasing popularity of beating-heart coronary surgery has raised concerns and doubts about the quality of the coronary anastomoses performed. Intraoperative graft patency verification methods are not commonly used after coronary surgery and, most of the cardiac surgeons, rely on the simple clinical signs (electrocardiogram tracings and hemodynamic stability) to make a diagnosis of coronary graft occlusion. New transit time ultrasound based methods for graft-patency verification have been adopted in many centers during beating-heart and traditional bypass grafting. Although the results are very encouraging, correct interpretation of the flow findings may prove difficult if specific rules are not properly followed. Flow curves, pulsatility index, and flow values should always be considered simultaneously before revising a coronary graft. Measurements should also be always performed with and without a proximal coronary snare. This article summarizes the main features of flowmetry and provides some technical pitfalls and suggestions to achieve an adequate intraoperative flow measurement adopting the transit time method.

Anastomosis, Surgical↗
PubMed2000

Preoperative angiography and intraoperative transit time flow measurement to detect coronary graft patency in reoperations: an integrated approach--a case report.

Coronary angiography is the gold standard for preoperative diagnosis of coronary artery disease. In reoperative coronary artery surgery the physiologic significance of suspect lesions by angiography can be confirmed by direct intraoperative measurement of blood flow in the old grafts; such interpretation can prevent unnecessary graft revisions.

Aged↗
PubMed2000

Posterior thoracotomy for reoperative coronary artery bypass grafting without cardiopulmonary bypass: perioperative results.

BACKGROUND: This retrospective study evaluates morbidity and mortality of reoperative coronary artery bypass grafting (CABG) without cardiopulmonary bypass (CPB) using a posterior thoracotomy to revascularize the lateral aspect of the heart. METHODS: From January 1995 to July 1999, reoperative CABG without CPB was performed on 67 selected patients using a left posterior thoracotomy approach. Preoperative risk factors, postoperative mortality, and major complications were derived from the New York State database. RESULTS: All patients were operated on without CPB. A total of 1.3 grafts per patient were performed. Freedom from major complications was 95.5%. There were no postoperative cerebro-vascular accidents (CVA) or new neurological deficits. Two patients (3%) had a perioperative acute myocardial infarction. The actual mortality rate was 4.5% (3/67), the expected mortality was 5.1% and the calculated risk adjusted mortality was 2.1%. CONCLUSIONS: Reoperative CABG without CPB to revascularize selected coronary artery targets can be safely performed using a posterior thoracotomy approach.

Aged↗
PubMed2000

Technical tips and pitfalls in OPCAB surgery: the buffalo experience.

The Center for Minimally Invasive and Robotic Heart Surgery has performed more than 1,500 off-pump coronary artery bypass (OPCAB) procedures since 1995. The operation has changed significantly based on experience and development of new tools. These improvements have made the operations safer and applicable to more patients. No patients are presently scheduled for on-pump bypass surgery in our center. The purpose of this paper is to describe some of the problems and pitfalls we have experienced and how to avoid them.

Coronary Artery Bypass, Off-Pump↗
PubMed2000

Effects of anti-oxidizing vitamins on in vitro cultured porcine neonatal pancreatic islet cells.

Oxidative stress may cause severe cellular damage to both allo- and xeno-transplanted islets, additional to islet graft-directed immunity, in diabetic patients. We thus aimed to examine the effects of antioxidants on in vitro culture-maintained, neonatal porcine cell clusters (NPCCs). NPCCs were treated with antioxidants (vitamins D3 and E) by a certain time of their maturation and differentiation process. Insulin recovery showed that both vitamins D3 and E, unlike untreated controls, resulted in preservation of the islet function for significantly long periods of time. Such effects were also confirmed during NPCCs in vitro static incubation with high glucose. Furthermore, morphologic examination of NPCCs demonstrated that at 16 days of cell culture beta-cell clusters were significantly larger and more intact when exposed to the vitamins as compared to controls. According to these preliminary results, because the employed vitamins, known to retain anti-oxidizing properties, seemed to clearly improve NPCCs morphology and function, they may represent a potentially useful tool for islet culture maintenance in the pre-transplant time period.

Animals↗
PubMed1999

Effects of some natural extracts on the acetylcholine release at the mouse neuromuscular junction.

Natural extracts have been proved to be useful in different human pathological conditions. The scientific consideration of the therapeutic potential of plant extracts is still inappropriate due to the lack of both pharmacological and epidemiological basic studies. Here, we started from an electrophysiological point of view, a study on the effects of two extracts on the acetylcholine (ACh) release at the neuromuscular junction. The extracts purified from Sugar cane (policosanol) and Psidium guajava (quercetin) have been submitted to this study. The wide epidemiology of these agents suggests therapeutic potentials not yet well outlined at the basic level. Our data demonstrate some interactions in the modulation of the ACh release at the mouse neuro-muscular junction, which are well correlated with the suggested molecular mechanisms. Policosanol enhances to a small extent either the spontaneous or the evoked ACh release. Furthermore, an increase of the rate of the conformational change induced at the nicotinic receptor-channel complex by ACh is also observed. Quercetin induced a reduction of the ACh evoked release. The possibility that this effect could be ascribed to some interaction with presynaptic calcium channel is noteworthy. The results are discussed in terms of a possible interference with acetylcholinesterase by policosanol and of a presynaptic molecular action of quercetin modulating the cytosolic calcium concentration.

Acetylcholine↗