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Biomedical subjects

M Bini

Publications and source records attributed to M Bini.

At least 19 recordsLinked to original sources

Long-term efficacy of endoscopic stenting in patients with stricture of the biliary anastomosis after orthotopic liver transplantation.

BACKGROUND AND STUDY AIMS: The choledocho-choledochostomy (CCS) stricture is one of the most frequent complications occurring after liver transplantation. Endoscopic retrograde cholangiography (ERCP) is the most sensitive method used to define the presence and narrowness of the stricture. Endoscopic stenting of the strictured anastomosis could provide an effective alternative to the surgical intervention. PATIENTS AND METHOD: ERCP was performed in 36 of 210 patients with liver transplantation and acute cholestasis or jaundice: in 15 cases biliary anastomotic stricture was found. These patients were endoscopically treated by long-term stenting of the common bile duct (CBD) (1 year) and followed up for more than 12 months after stent removal. RESULTS: In all cases the stenting procedure resolved the biliary obstruction syndrome within 7 days. At the end of the stenting period the CCS was dilated enough to allow adequate bile flow and absence of cholestasis. Moreover, in most patients (10) the anastomosis was kept patient for more than 1 year after stent removal, whereas only two patients had stricture recurrence and needed endoscopic restenting. Four patients dropped out of the study, respectively because of liver rejection (two), acute liver failure (one) and myocardial infarction (one). One patient who developed a stone of the transplanted CBD underwent surgical intervention. CONCLUSIONS: According to our data, the endoscopic stenting of the CBD might be considered as the first choice procedure in the setting of the biliary anastomotic strictures occurring after liver transplantation. It has proved to be safe and effective, avoiding the need for more invasive surgery, which in any case should be considered for nonresponsive patients.

Adult

An electrical model of biological tissues undergoing hyperaemia.

Tissue hyperaemia is a physiological consequence of the temperature increase that follows, for example, the absorption of electromagnetic or ultrasound power in clinical diathermy. Diathermy, as well as other physical therapies (for example massotherapy), affects the local blood content of tissues through various mechanisms (vasoconstriction/dilatation, opening/closing of precapillary sphincters). A method for evaluating hyperaemia in superficial and medium-depth tissues has been recently proposed, which is based on four-electrode impedance measurements. A microcirculation model has also been developed to describe the hyperaemic effects of local diathermic therapy. This paper describes an electrical model of the tissues in hyperaemic conditions which allows us to correlate electrical impedance measurements to microcirculation modifications.

Biophysical Phenomena

Hyperaemia evaluation in clinical diathermy by four-electrode impedance measurements.

The four-electrode electrical impedance measurement technique is proposed for the evaluation of the hyperaemia variation in tissues treated by diathermic therapy. An impedance meter suitable for such measurements is described, and an electrical model of the heated tissues, concerning the impedance variation during diathermy and its relation with hyperaemia, is presented. The occurrence of the substantial contribution of blood to the overall transverse impedance is demonstrated by comparing the experimental results with those arising from a 2D electrical/thermal model of the treated tissues. A two-admittance model is proposed to explain the electrical behaviour of the tissues treated by diathermy. The model allows us to separate the impedance violation due to the temperature dependence of tissue conductivity from that due to the change of tissue blood content. The results of preliminary measurements of tissue impedance on healthy volunteers treated by electromagnetic diathermy are presented and discussed, showing the feasibility of impedance detection of hyperaemia variations inside tissues.

Body Temperature

The effect of endoscopic sclerotherapy of esophageal varices on the development of gastric varices.

BACKGROUND AND STUDY AIMS: The effect of sclerotherapy of esophageal varices on the development of gastric varices is a controversial question. The aim of the present study was to evaluate prospectively the presence and development of gastric varices as a consequence of esophageal variceal sclerotherapy. PATIENTS AND METHODS: We prospectively studied 227 patients, all of whom had liver cirrhosis at the time of the first bleeding episode due to esophageal varices. All patients were treated with emergency endoscopic sclerotherapy, and further courses of sclerotherapy to eradicate the varices were given at seven-day intervals for three sessions, and then every fifteen days until eradication was complete. At the time of inclusion in the study, patients were divided in two groups: group A, with initial gastric varices, and group B, without any gastric varices initially. RESULTS: Group A included 138 patients (60.8%), in 99 of whom (71.7%) disappearance of the gastric varices was observed. In 63 cases (63.6%) the varices were eliminated during the sclerotherapy treatment, before the eradication of esophageal varices; in 36 cases (36.4%), the gastric varices disappeared after the eradication of the esophageal varices. Group B included 89 patients (32.9%); in 78 of them (87.6%), no appearance of gastric varices was observed, while in 11 (12.4%), gastric varices appeared. CONCLUSION: From these data, it can be concluded that sclerotherapy of esophageal varices cannot be a determinant factor either for the appearance of gastric varices or for their subsequent risk of bleeding.

Adult

Non-bleeding visible vessel treatment: perendoscopic injection therapy versus omeprazole infusion.

BACKGROUND: The non-bleeding visible vessel in a peptic ulcer is the highest risk factor for a bleeding recurrence among not actively bleeding lesions. Perendoscopic injection of sclerosing compounds is usually used as prophylaxis against rebleeding. METHODS: Forty-two patients with visible vessels in a peptic ulcer at an emergency endoscopic procedure have been studied: 21 patients underwent prophylactic perendoscopic hemostasis, and 21 patients were infused with omeprazole intravenously. RESULTS: Eight patients (19%), four in each group, had early rebleedings (within 48 h after the enrollment). There was no significant difference between the two types of treatment. At the endoscopic control after 48 h there were significantly more lesions with higher risk of rebleeding (Forrest IIa and IIb) in the group treated with perendoscopic hemostasis. CONCLUSIONS: Our data suggest that omeprazole infusion is a valid alternative to injection treatment of non-bleeding visible vessels.

Adult

The use of a long-acting somatostatin analogue (octreotide) for prophylaxis of acute pancreatitis after endoscopic sphincterotomy.

Acute pancreatitis is a serious complication of endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic sphincterotomy (EST). In addition, serum pancreatic enzymes increase without clinical symptoms in about 40-50% of patients undergoing these endoscopic procedures. We evaluated the potential of octreotide, a long-acting somatostatin analogue, to prevent these complications in patients who underwent EST for choledocholithiasis. 151 patients were randomly allocated to two groups (A and B). Group A was given 0.1 mg of octreotide subcutaneously 120 and 30 min before EST and four hours after; group B was given a placebo. Serum amylases (normal range 20-220 IU/l) were measured before premedication and 4, 24, and 48 hours after the end of endoscopy. After EST, the increase in the mean serum amylase was greater in the control group, but the difference was statistically significant only at the 48-hour measurement. There were five cases of acute pancreatitis in each group, with a trend (but not statistically significant) toward less severe pancreatitis in the treated group. In the control group, one patient with acute pancreatitis died. In conclusion, octreotide does not seem to prevent acute post-EST pancreatitis.

Acute Disease

High permittivity patch radiator for single and multi-element hyperthermia applicators.

This paper describes a compact, low-profile patch radiator which is the base element for efficient, small-size applicators suitable for superficial hyperthermia. The design criteria and the technological processes involved are presented. The electromagnetic characteristics of the patch element are outlined, and possible application of the radiator are discussed.

Ceramics

Silent ischemia in unstable angina is related to an altered cardiac norepinephrine handling.

BACKGROUND: Inferential evidence suggests that silent ischemia might be related to sympathetic activity. Study of [3H]norepinephrine kinetics is a suitable tool to assess the regional sympathetic activity. This method was applied to investigate whether silent myocardial ischemia in unstable angina is related to and depends on cardiac sympathetic overactivity. METHODS AND RESULTS: Patients with active unstable angina were compared with patients with inactive unstable angina, stable effort angina, and controls. Silent myocardial ischemia was evaluated by three 24-hour Holter monitoring periods on alternate days, and [3H]norepinephrine kinetics was assessed under rest conditions and following the cold pressor test. Simultaneously, catecholamine concentrations were measured in the aortic, coronary sinus, and peripheral venous blood. Different than the other groups (p = 0.0013), in patients with active unstable angina, the majority of silent ischemic episodes occurred without increase in heart rate. These patients had a positive coronary sinus-aorta norepinephrine gradient, both at rest and following the cold pressor test. [3H]Norepinephrine kinetics demonstrated an increased selective cardiac spillover, both at rest and, even more, after the cold pressor test. Reduced cardiac [3H]norepinephrine extraction also was found. A significant relation was found between the number of ischemic episodes or the overall duration of silent ischemia and norepinephrine spillover, both at rest and following cold application. CONCLUSIONS: During the acute phase of unstable angina (but not in the quiescent phase or in stable effort angina), a disorder in cardiac norepinephrine handling occurs. This results in a reflex cardiac sympathetic overactivity that plays a major role in the occurrence of silent myocardial ischemia.

Angina, Unstable

Effect of heparin, aspirin, or alteplase in reduction of myocardial ischaemia in refractory unstable angina.

399 out of 474 inpatients with unstable angina were monitored for 48 h and 97 of these were found to be refractory to conventional antianginal treatments and entered a randomised double-blind study. With the initial protocol heparin infusion or bolus were compared with aspirin; with a modified protocol, heparin infusion, the best of these three treatments, was compared with alteplase. Patients were monitored for 3 days after starting treatment and then observed clinically for 4 more days. On the first days of treatment heparin infusion significantly decreased the frequency of angina (by 84-94%), episodes of silent ischaemia (by 71-77%), and the overall duration of ischaemia (by 81-86%). Heparin bolus and aspirin were not effective. Alteplase caused small (non-significant) reductions on the first day only. Only minor bleeding complications occurred.

Administration, Oral

Control of the physical parameters in local electromagnetic hyperthermia.

The evaluation of the clinical results in experimental applications of local electromagnetic hyperthermia requires strict control of the physical parameters of the treatment and adhesion to close medical protocols. Development and application processes in close cooperation between physicians and electromagnetic experts are reported and discussed, on the basis of experimental and theoretical research work. Attention is concentrated on a 434 MHz apparatus, where the fundamental physical limits have been identified and the operating features in the clinical practice have been evaluated. The cases eligible for treatment were chosen according basically to the limitations posed by depth, volume and steep temperature gradients. Several cases are reported mainly in association with radiotherapy. Lines of technical improvement are suggested, mainly based on the development and optimization of lower-frequency applicators.

Body Temperature

Thrombosis of portal vein in absence of hepatic disease.

Of 602 patients referred for portal hypertension during a 20 year period, 18 children (mean age of 5.0 years) and 29 adults (mean age of 26.5 years) had thrombosis in the portal bed with a healthy liver (7.8 per cent incidence). In 29 of the 47 patients we studied, the causative factor remained obscure. Variceal hemorrhage occurred in all and was the indication for our observation and treatment. In 11 adult patients (mean age of 22.1 years), surgical treatment was not performed because of reluctance of the patient or because of technical reasons: nine of the patients rebled and one patient died because of massive bleeding. Direct procedures on esophageal varices had a high rate of rebleeding (seven of 11 patients) independent of the age of the patient when the operation was performed. In 13 patients, shunting offered a good chance of long term protection: three of the 13 rebled at a mean follow-up study of 5.7 years. No recurrence of bleeding was observed in 15 patients when variceal eradication had been obtained after chronic endoscopic sclerotherapy at one to eight years of follow-up study (mean of 3.9 years). The data from this study indicate that sclerotherapy should be the first choice of treatment to control recurrent bleeding in extrahepatic portal hypertension caused by thrombotic obstruction, particularly in the young patient.

Adolescent

[Evolution of pregnancy in 14 patients with lupus nephropathy].

Authors have examined 14 pregnant patients with renal involvement by systemic lupus erythematosus. Variations in blood creatinine, proteinuria and blood pressure were considered in the prepregnancy, pregnancy and postpartum periods in relation to the histologic results of renal biopsy and obstetric outcome.

Adult

Analysis of electric and magnetic fields leaking from induction heaters.

Results are presented of an investigation on electric and magnetic fields leaking from inductive (magnetic) heaters that are used for thermal processing of high-power electron tubes and lasers in an industrial plant. Measurements of electric and magnetic fields were done using both commercially available and laboratory-developed instrumentation. Isotropic H-field sensors were developed to allow quantitative evaluation of high-intensity magnetic fields. Ten induction heaters with nominal A.C. power ranging from 2.5 kW to 15 kW and operating at frequencies between 300 kHz and 790 kHz were surveyed. Electric field strengths up to 8 kV/m and magnetic field strengths up to 20 A/m were measured.

Environmental Exposure