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L Leonardi

Publications and source records attributed to L Leonardi.

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

[Radiation protection in the use of tracers in radioguided breast surgery].

PURPOSE: Recent techniques in nuclear medicine have permitted to implement new procedures useful in surgery. Among these, the procedures for locating sentinel lymph nodes and nonpalpable breast lesions are of great interest. The protocols for the location of the sentinel lymph node and for the radioguided location of occult lesions developed at the European Institute of Oncology (IEO, Milan) are based on the administration of radiopharmaceuticals labelled with Technetium-99m (99mTc). We evaluated the dosimetric data relative to patients and hospital personnel to assess whether specific radiation protection procedures are needed. MATERIAL AND METHODS: Fifty patients with nonpalpable breast lesions and 50 patients with suspected lymph node involvement were enrolled in this study. All the patients underwent surgery the day after in-loco administration of the radiopharmaceutical (11 MBq of 99mTc). The absorbed dose to the hospital personnel was estimated from the air kerma rate measured by ionization chamber at different distances from the patients at 0 and 16 hours after the radiopharmaceutical administration. In order to evaluate radiation protection for patients, absorbed doses were measured positioning thermoluminescent dosimeters on the patient's skin for about 16 hours. In the operating room, activity was measured on some excised tissues (lymph nodes and tumors) and on surgical instruments. RESULTS: Absorbed doses were very low for the clinical staff also in case of prolonged patient assistance. After 100 cases, the surgeon mean absorbed dose to the hands and mean effective dose were .45 mGy and .09 mGy, respectively. These values correspond to 1% of the annual dose limit to the hands and to 10% of the annual equivalent effective dose recommended for the population (ICRP 60 and law by decree 230/95). The absorbed dose to healthy tissues of the patients were lower than 1 mGy (mean values: contralateral breast: .9 mGy; abdomen .45 mGy). The mean activity detected in the excised tissues was 9 kBq and 900 kBq in the sentinel lymph nodes and in the tumor lesions (injection site), respectively. The activity detected on the surgical instruments, higher on gauzes (< 100 kBq), was negligible. CONCLUSIONS: From the radiation protection point of view, the data support the validity of our protocols. Absorbed doses to the hospital personnel are low and require neither a radiation protection control nor a classification of exposed workers as classes A or B. Special containers for radioactive wastes are necessary in the administration room but not in the operating room, where the levels of possible contamination are negligible.

Breast Neoplasms↗
PubMed1997

Role of glucose-6-phosphate dehydrogenase inhibition in the antiproliferative effects of dehydroepiandrosterone on human breast cancer cells.

Epidemiological and experimental studies suggest that dehydroepiandrosterone (DHEA) exerts a protective effect against breast cancer. It has been proposed that the non-competitive inhibition of glucose-6-phosphate dehydrogenase (G6PD) contributes to DHEA antitumor action. We evaluated the effects of DHEA on G6PD activity and on the in vitro proliferation of two human breast cancer cell lines, MCF-7 (steroid receptor positive) and MDA-MB-231 (steroid receptor negative), in a serum-free assay. DHEA inhibition of G6PD was only found to occur at concentrations above 10 microM; at these high concentrations, the growth curve was parallel to the enzyme inhibition curve in both cell lines. In contrast, at concentrations in the in vivo breast tissue concentration range, neither cell growth nor enzyme activity was inhibited. The results failed to confirm DHEA's putative anti-tumor action on breast cancer through G6PD inhibition, as the enzyme blockade only becomes apparent at pharmacological concentrations of the steroid.

Breast Neoplasms↗
PubMed1997

[Ambulatory phlebectomy. Literature review and personal experience].

Outpatient varicose veins surgery, "Phlébectomie Ambulatoire" (FA) introduced by R. Muller in 1966, is now a widespread technique; modified by many authors with personal tips, FA enables most lower limb varicosities to be treated on an outpatient basis and under local anaesthesia. To achieve good functional results, an accurate preoperative diagnostic examination is mandatory; the authors present a review of the indications of FA and their personal experience. Precision in performing micro-incisions, accurate dissection of the varicosities in the subcutaneous tissue and an adequate postoperative elastic bandage guarantee good aesthetic results. At present the treatment of Saphena magna with FA is debated, but some authors have already reported encouraging results.

Adult↗
PubMed1997

Acquisition protocol for breast cancer imaging with technetium-99m-labeled synthetic peptide and technetium-99m-MDP.

UNLABELLED: Technetium-99m-MDP and, recently, a 99mTc-labeled synthetic decapentapeptide have been shown to localize in breast lesions. Our goal was to develop an acquisition protocol to improve image quality, to improve detection of axillary lymph nodes with disease and to compare the utility of the new radiotracer to 99mTc-MDP. METHODS: Ninety-three patients with documented breast carcinoma were studied. Thirty-eight patients were studied in the supine position with anterior and lateral views: eight patients were injected intravenously with 600-740 MBq 99mTc-EPPT and 30 patients with the same activity of 99mTc-MDP. A second group of 55 patients was studied using the same total activity: 20 patients were injected with 99mTc-EPPT and 35 patients with 99mTc-MDP. To improve results, patients were positioned standing up with their arm raised. The breast with a marker over the nipple touched the collimator in the oblique-lateral position. Early planar images (2-5 min postinjection) were acquired with this positioning for the healthy and the tumor breast, collecting 1500 K counts in a 256 x 256 matrix. Imaging of the axillary regions was performed while the patients were positioned supine and a frontal image was obtained at 10-15 min postinjection for 1800 K counts. RESULTS: This diagnostic study produced good quality images, with the breast lesions and axilla visualized. The positions had limitations due to the overlapping of other organs and to the proximity with the chest wall. CONCLUSION: Using this protocol, all primary lesions and 50% of the axillary lymph nodes with 99mTc-MDP, and 35% with 99mTc-EPPT, were detected as documented by histology. Our protocol may represent an improvement in the diagnosis and staging of breast cancer.

Axilla↗
PubMed1995

Inhibitory effect of hydroxyflutamide plus tamoxifen on oestradiol-induced growth of MCF-7 breast cancer cells.

The antiandrogen flutamide has been reported to exert antiproliferative actions on breast cancer both in vitro and in vivo. Here we study the action of its active metabolite hydroxyflutamide on the oestradiol-induced growth of MCF-7 breast cancer cells. The results show that the antiandrogen inhibits the cell growth. Moreover hydroxyflutamide adds its antiproliferative effect to the action of the antioestrogen tamoxifen. The inhibitory effect is dose-dependent and it is unaffected by tamoxifen concentrations up to levels able to block oestrogen receptors completely. Dihydrotestosterone experiments parallel those on hydroxyflutamide. When the two substances are administered together, neither antagonistic nor additive effects are appreciable. Data are consistent with an androgen-like action of hydroxyflutamide on breast cancer cells. The antiproliferative effect of hydroxyflutamide, without virilizing side-effects, suggests that it is worth exploring its possible employment together with antioestrogens in the treatment of breast cancer patients.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

5-En-androstene-3 beta,17 beta-diol inhibits the growth of MCF-7 breast cancer cells when oestrogen receptors are blocked by oestradiol.

Adrenal androgens show a dual and apparently opposite effect on the growth of oestrogen-responsive breast cancer: they stimulate growth on their own, but counteract the growth-stimulatory effect of oestrogens. Focusing on the inhibitory action we have studied the effects of 5-en-androstene-3 beta,17 beta-diol (ADIOL) on the growth of oestrogen-responsive MCF-7 breast cancer cells in the presence of oestrogens (oestradiol and diethylstilboestrol), antiestrogens (tamoxifen) and antiandrogens (hydroxyflutamide). The inhibition of oestrogen-stimulated growth, attained with nanomolar concentrations of ADIOL, was not modified by increasing concentrations of diethylstilboestrol up to 100 nM. This inhibition was counteracted by antiandrogens, which were unable to block the ADIOL stimulatory effect in steroid-free medium. On the other hand, in the presence of tamoxifen ADIOL showed an additive antiproliferative activity also in steroid-free medium, rather than the usual stimulatory effect. These results suggest that ADIOL stimulates breast cancer cell growth via oestrogen receptors, but inhibits oestrogen-stimulated growth via androgen receptors.

Androstenediol↗
PubMed1993

Model for a controlled-release drug delivery safety system with permeable and erodible coatings.

Models of drug delivery devices that employ erodible permeable coatings must take care to avoid the unacceptably high rate of release that arises as the erodible coating disappears and the barrier to drug release vanishes. One solution to this safety problem has been to exhaust the drug reservoir just before this condition occurs. This design has the disadvantage of placing demands of high accuracy on the quality control in the fabrication of the device. A drug delivery system of cylindrical symmetry is proposed that uses two permeable coatings on a drug-containing core. Only the outer of the two coatings is erodible; the inner safety coating and the core are inert. Calculations are performed to design the device that can yield constant drug delivery rates while avoiding the possibility of explosive late drug release.

Drug Delivery Systems↗
PubMed1992

Esophageal electrodes allow precise assessment of cardiac output by bioimpedance.

OBJECTIVES: To analyze the impact of the position of the thoracic external electrodes on the values of cardiac output measured by electrical bioimpedance and to compare the results obtained by bioimpedance with those values determined by thermodilution in critically ill patients. DESIGN: Open, prospective, comparative trial. SETTING: ICU of a teaching hospital. PATIENTS: Twenty healthy volunteers and ten critically ill patients. INTERVENTIONS: Measurements of cardiac output by bioimpedance at rest and after physical activity in normal volunteers and after changing the neck or xiphoid electrodes. Comparisons of cardiac output obtained by thermodilution and bioimpedance with internal and external electrodes in patients. MEASUREMENTS AND MAIN RESULTS: Mean +/- SD values are presented. Cardiac output values at rest and after exercise were 6.7 +/- 1.3 and 10.8 +/- 2.6 L/min at rest and after exercise, respectively (p less than .001). Displacement of the xiphoid electrodes 3 cm in the caudal direction was accompanied by a decrease of the mean cardiac output from 7.1 +/- 1.2 to 5.8 +/- 1.3 L/min (p less than .001) and displacement 3 and 6 cm cranially was accompanied by increases in cardiac output from 7.1 +/- 1.2 to 8.1 +/- 1.4 L/min (p less than .001) and 8.6 +/- 1.5 L/min (p less than .001), respectively. In the ten patients, cardiac output measurements were virtually identical when results obtained by thermodilution (6.7 +/- 3.1 L/min) were compared with those results obtained by bioimpedance using internal esophageal (6.6 +/- 3.1 L/min), but not external (4.7 +/- 1.6 L/min) electrodes. CONCLUSIONS: a) The values of cardiac output derived from measurements obtained by bioimpedance using internal electrodes were comparable with those values derived from thermodilution. b) Values of cardiac output from bioimpedance studies with external electrodes were dependent on the position of the xiphoid electrodes.

Adult↗
PubMed1992

A computer-assisted automatic method for myelinated nerve fiber morphometry.

This paper describes a computer-assisted automatic method developed for myelinated nerve fiber morphometry. IBAS image analysis system was used. One-micron thick sections of sural nerve were stained with p-phenylenediamine. Dark myelin sheaths, standing out against a pale background, were identified by a binary transformation of the computer-stored image. Different parameters of the fibers as well as of the axons can be measured. The automatic system allows operator-interactive manipulation, if required, to avoid inclusion of wrong histologic structures. A large spectrum of statistics facilities are available. We performed a comparison between automatic and semi-automatic analysis. Measurements resulted virtually overlapping, but time was three to four times shorter with automatic procedure. The method here described is accurate and reliable, and permits economy of time and effort.

Biopsy↗
PubMed1991

[Preventive cytolytic treatment following heart transplantation: ATG versus OKT3].

The postoperative prophylactic cytolytic therapy with rabbit-ATG and OKT3 after heart transplantation are compared. The first 20 recipients were treated with ATG (5 days), the next 20 with OKT3 (14 days). The medium histological rejection grade (Texas classification) was significantly higher after 2 weeks in ATG group and after 4 weeks in OKT3 group. The linearised rejection rate was 7.1 (ATG) vs. 0.7 (OKT3) (p less than 0.005) at 2 weeks, resp. 3.6 vs. 8.6 (p less than 0.05) and 1.3 vs. 2.9 (p less than 0.005) at 4 weeks and 2 months. After 3 months there was no difference in histological rejection grade (3.6 +/- 1.5 vs. 3.3 +/- 1.7) and linearised rejection rate (2.4 vs. 2.6 per 100 days and patient) between the two groups. Severe rejections are more frequent after OKT3 (6 vs. 11) and probability of rejection free survival is higher after ATG (25% vs. 0%, resp. 21% vs. 0% after 2 resp. 3 months; p less than 0.05). In this study we find no short and medium term benefit of a rejection prophylaxis with OKT3 (14 days) compared with ATG (5 days). Acute allograft rejections in OKT3 group tend to be more severe with a higher mortality.

Antibodies, Monoclonal↗
PubMed1990

[Cytomegalovirus (CMV) infection: a frequent and life-threatening complication in heart transplant patients].

We investigated the clinical relevance of cytomegalovirus infection in our heart transplant recipients (n = 48). There was a high incidence of CMV-infection in patients where IgG positive donor versus IgG negative recipient was present. A total of 5/8 patients (= 62.5%) showed severe clinical CMV-infection with pneumonitis, colitis or tonsillitis besides general malaise, requiring long hospital treatment (2 to 24 weeks). CMV-infection is a frequent and threatening complication in patients after heart transplant (HTPL). We discuss the various managements in diagnosis, prophylaxis and treatment.

Antibodies, Viral↗
PubMed1990

[Graft rejection reaction and immunosuppression following heart transplantation].

Acute rejection is the most important factor influencing mortality after heart transplant. Acute rejection occurs at least once in over 95% of the patients in the early phase after heart transplant. In the vast majority of episodes of acute rejection clinical symptoms are absent. The regular performance of endomyocardial biopsy after heart transplant allows histological diagnosis of rejection episodes as well as follow-up control of rejection treatment. This overview points to the major problems regarding acute rejection and immunosuppressive regimen in heart transplant recipients.

Graft Rejection↗
PubMed1990

[Toxoplasmosis in the heart transplant patient].

Toxoplasmosis is a well-known problem under immunosuppressive conditions in cardiac transplant patients. In our series 12% of the patients (8 of 65) had clinical and/or serological signs of active toxoplasmosis. Due to its serious prognosis once the clinical process has started we favor a generous diagnostic interpretation of the serological results and a broad indication to drug therapy.

Animals↗
PubMed1990

[Long-term follow-up after heart transplantation].

Actuarial survival rate two years after heart transplant in our patients is 90%. The most patients report excellent quality of life (NYHA I) and present definitely improved work load capacity as well as normal cardiac hemodynamic assessment two years after transplant. The major problems in the long follow-up of heart transplant recipients are accelerated coronary disease (graft atherosclerosis), arterial hypertension and renal function impairement.

Cause of Death↗