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Biomedical subjects

F Di Gregorio

Publications and source records attributed to F Di Gregorio.

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

[Intensive intravenous chelation in thalassemic patients with iron overload].

The effects of an alternative chelation program in thalassemic patients with severe iron overload are investigated. The schedule of treatment, feasible at home, consists in the administration of deferoxamine intravenously (100 mg/kg/die 8 hours 10 days a month), followed by 50 mg/kg/die subcutaneously in the remaining 20 days of the month. The results in 34 patients who underwent this program over 8 months are reported. After intensive chelation therapy serum ferritin and transaminase levels were significantly lower, and daily urinary iron excretion values were significantly higher when compared to the levels observed before the treatment. After the period of study, echocardiography revealed an ejection fraction (EF) significantly higher in 15 out of 34 cardiopathic patients. In conclusion, the alternative chelation program is effective in reducing iron overload of thalassemic patients, protecting them also against cardiac disease.

Adolescent↗
PubMed1997

Immune status and the immune response to hepatitis B virus vaccine in thalassemic patients after allogeneic bone marrow transplantation.

We evaluated the immune status with respect to HBV and the immune response to readministration of HBV vaccine in a series of 20 patients with homozygous beta-thalassemia, aged 6-23 years (mean age: 13.0 +/- 4.2) who had undergone allogeneic bone marrow transplantation (BMT). Thirteen of them (group A), had received three doses of plasma-derived HBV vaccine from 7 to 5 years before BMT and 4-5 weeks after the last dose of vaccine, they had had high serum levels of HBV antibodies (anti-HBs). The remaining seven patients (group B) had had clinical symptoms and laboratory evidence of HBV infection in childhood with markedly elevated serum of anti-HBs. Before revaccination, a significantly lower percentage of patients (P < 0.005) with seropositive levels of anti-HBs was observed in group A than in group B. After administration of the second dose of HBV vaccine the percentage of subjects with protective levels of anti-HBs rose to 100% in both groups of patients even if the geometric mean of titers of anti-HBs increased more significantly in group B patients than in group A. We conclude that the serum levels of anti-HBs afforded by HBV vaccine administered from 7 to 5 years previously are very low and probably non-protective in most beta-thalassemic patients after allogeneic BMT, and that at least two doses of HBV vaccine should be readministered from 18 to 24 months after BMT to achieve adequate and long-term protection from HBV.

Adolescent↗
PubMed1997

Alpha-interferon treatment of chronic hepatitis C after bone marrow transplantation for homozygous beta-thalassemia.

No experience has been reported to date in treating chronic hepatitis C virus (HCV) infection with interferon (IFN) therapy after BMT, mainly due to concerns related to the impact of an immunomodulatory drug in patients who are immunologic and haematologic chimeras. However, chronic inflammatory activity related to HCV infection results in a chronic fibrogenous mechanism potentially leading to liver cirrhosis and hepatocellular carcinoma. Moreover, patients transplanted for beta-thalassemia could be at greater risk because of concomitant iron overload and pre-existing fibrous liver damage. Eleven patients with serological, biochemical, histological and molecular biological evidence of HCV infection were included in the study and treated for 6-12 months with recombinant IFN 24-65 months following BMT. The serum alanine aminotransferase (ALT) was persistently elevated (range 85-1242 U/l; mean 416) for at least 1 year prior to IFN treatment. Ten patients completed the protocol; five were considered as responders to treatment. In these five patients the liver histology showed an overall reduction of inflammation and necrosis: histological inflammatory activity improved from chronic active hepatitis (CAH) to chronic persistent hepatitis (three patients) or minimal residual inflammatory activity (two patients). The Knodell total activity score varied from 5.4 (range 3-9) to 1.4 (range 1-2; P = 0.05). All responding patients revealed negativization of serum HCV-RNA, that has been persistent in four (follow-up 1-3 years). ALT level fell to 15-80 U/l (mean 52; P = 0.0027). No major complications occurred during the therapy and no influence on marrow engraftment parameters were noted. We conclude that IFN therapy does not adversely interfere with engraftment and that it is a feasible therapy for treatment of chronic hepatitis C virus after BMT.

Adolescent↗
PubMed1997

An alternative to continuous subcutaneous infusion of desferrioxamine in thalassaemic patients.

Sixteen patients with thalassaemia major were treated with subcutaneous desferrioxamine (DF) 50 mg/kg/d, 5 consecutive days a week, for 8 weeks. Every other week the total dose was administered by 12 h infusion pump or by rapid injection of the same dose (25 x 2 mg/kg) twice a day. The two methods of DF administration produced no significant differences in urinary iron excretion. No significant changes in serum ferritin levels were observed at the end of the study. Compared with continuous infusion, rapid injection is equally efficacious, does not induce serious side-effects, is better accepted by the patients, and can improve their compliance to the iron-chelating therapy.

Adolescent↗
PubMed1997

Retroconduction selective recognition in wide-dipole floating atrial sensing. The Multicenter Study Group.

Effective discrimination of retrogradely conducted P waves would allow distinguishing sinus tachycardia from supraventricular tachycardias due to AV or nodal reentry, and would prevent pacemaker-mediated tachycardia in AV sequential pacing. This might be especially relevant in VDD implants, where retroconduction could be induced by escape ventricular stimulation. In order to analyze the respective waveform properties, anterograde and retrograde atrial signals were recorded by a wide floating electrode dipole, on the implantation of a permanent single-pass lead for VDD pacing. Generally, bipolar recording did not allow reliable discrimination, while the signal nature could be readily diagnosed from the main features of the unipolar atrial electrograms. The unipolar waveform recorded under sinus rhythm in high right atrium, close to the superior vena cava opening (proximal EGM), started with a negative deflection in 88% of the patients. In 7% of the patients, the first deflection of the signal was positive in some cardiac cycles only, and, on the average, the amplitude of the positive phase was not higher than 5% of the signal peak-to-peak amplitude. Conversely, under retroconduction, the starting deflection attained higher positive values in 98% of the patients, being stably over 15% of the peak-to-peak amplitude in 86% of the Furthermore, in 69% of the cases, the lag time between the onset of the negative deflection of proximal and distal (mid-low atrium) unipolar EGM changed unambiguously when retroconduction occurred, exceeding the range of variation observed in each patient during sinus activity. The combined evaluation of unipolar EGM shape and lag time allowed specific retroconduction recognition in 95% of the patients. We suggest that this approach may yield useful information for the discrimination of retrograde atrial signals, provided that the recording dipole is sufficiently long and the proximal electrode is properly positioned in the high right atrium.

Cardiac Pacing, Artificial↗
PubMed1997

Persistence of Mediterranean anaemia in Sicily.

We report 40 cases of homozygous beta thalassaemia, aged between 3 and 24 months, who were observed between January 1990 and June 1996 at the Thalassaemia Centre, Paediatric Department, Catania University. A questionnaire was used to find out the parents' knowledge of their risk before the birth of the affected children and showed that the persistence of Mediterranean anaemia in Sicily was mainly because of the following reasons: (1) poor information (62.5%), (2) laboratory error (12.5%), (3) difficulty in the differential diagnosis of beta thalassaemia trait (10%), and (4) not performing prenatal testing or selective abortion of an affected fetus (15%). We conclude that improved preventive measures at various medical and social levels can remove risk factors and so further reduce the incidence of Mediterranean anaemia in Sicily.

Genetic Counseling↗
PubMed1997

High prevalence of myocardial ischemia and vasoconstrictive hormonal release in hypertension during chronic renal failure.

OBJECTIVE: Indexes of myocardial ischemia and vasoconstrictive hormonal release were evaluated in order to investigate the difference between essential hypertension and hypertension during chronic renal failure. BACKGROUND: Arterial hypertension induces several cardiovascular alterations that reflect themselves either on the heart and/or on the coronary blood flow enhancing the cardiovascular risk. Since chronic renal failure can influence the neuroendocrine response, various mechanisms involved in hypertension during chronic renal failure are still unclear. High endothelin 1 (ET-1) levels have been found both in arterial hypertension and during chronic renal failure. Interestingly, either ET-1 or catecholamines seem also to be implied in the pathogenesis of myocardial ischemia. METHODS: 20 hypertensive uremic and 20 essentially hypertensive patients underwent echocardiographic wall motion and wall thickening analysis performed at baseline and immediately after the end of exercise. Simultaneously, myocardial perfusion was evaluated by 99mTc-MIBI-SPECT. In addition, plasma norepinephrine and ET-1 concentrations were measured at baseline and at peak exercise. RESULTS: The segmental radionuclide analysis showed a greater ischemic degree in hypertensive uremic patients. Yet, we were able to identify one or more regions of the left ventricle in which both systolic thickening measurements and wall motion after exercise were impaired. After exercise, wall thickening impairment was correlated with both wall motion abnormalities (r = 0.72, p < 0.01) and MIBI ischemic grade (r = 0.82, p < 0.001). Basal and after-exercise plasmatic norepinephrine and endothelin levels were higher in hypertensive uremic than in essentially hypertensive patients. Moreover, there was a significant correlation between increments in norepinephrine concentration and MIBI perfusion defects, and between the increment in ET-1 concentration and both MIBI perfusion defects, or kinetic alterations assessed by wall motion as well as by wall thickening. CONCLUSIONS: This is the first cross-sectional study in which a higher degree of myocardial ischemia has been observed in hypertensive uremic patients combined with an enhanced plasma release of both norepinephrine and ET-1. This phenomenon may contribute to enhance the cardiovascular risk of these patients.

Aged↗
PubMed1997

Effect of alpha-interferon on natural killer cell activity and lymphocyte subsets in thalassemia patients with chronic hepatitis C.

The variation of natural killer (NK) cell activity and lymphocyte subsets 20 h after a single test dose of alpha-IFN, was studied in 17 thalassemic patients with chronic hepatitis C. All patients had suspended the alpha-IFN therapy at least 12 months before the study: 10 were considered responders and 7 nonresponders. Also NK cell cytotoxicity after in vitro incubation with alpha-IFN was studied. The administration of a single dose of alpha-IFN increased NK cell cytotoxic activity significantly in the group of responders and in non-responders; moreover the NK cell cytotoxic activity after alpha-IFN in vitro incubation increased both in responders and nonresponders, but to a lesser degree than in healthy controls. Absolute values of CD4+ and CD8+ lymphocytes decreased significantly only in responders. In conclusion, our data suggest that the variation of NK cytotoxic activity and lymphocyte subsets after a test dose of alpha-IFN can be considered a parameter related to IFN biological effects.

Adolescent↗
PubMed1997

Left ventricular function and perfusion in Becker's muscular dystrophy.

UNLABELLED: The aim of this study was to evaluate left ventricular (LV) perfusion and function in patients with Becker muscular dystrophy (BMD). METHODS: Fourteen male patients (age range 14-40 yr) with BMD were evaluated by 201Tl SPECT and radionuclide angiography both at rest and after dipyridamole stress test. RESULTS: All patients showed uptake defect demonstrated by 201Tl SPECT (mean 4.1 +/- 2.2 uptake defect/patient). Significant relationships (p < 0.05) were found between the number of uptake defects and rest LV ejection fraction (LVEF) (r = -0.54); peak filling rate (PFR) (r = -0.57) and dipyridamole LVEF (r = -0.65). Dipyridamole induced reversible uptake defects were found in 7/14 (50%) patients with BMD. The 14 patients were divided into two groups on the basis of the presence (Group A, n = 6) or the absence (Group B, n = 8) of severe irreversible uptake defect (i.e., < 50% 201Tl uptake). Group A showed lower values of PFR and LVEF when compared to patients of Group B. CONCLUSIONS: In patients with BMD there is a relatively high incidence of uptake defects and LV function (both at rest and after dipyridamole) appears to be related to the number of uptake defects. Moreover, the presence of severe irreversible uptake defects identifies a subgroup of patients with BMD characterized by a severely depressed LV function.

Adolescent↗
PubMed1997

The arterial blood supply of the pancreas: a review. IV. The anterior inferior and posterior pancreaticoduodenal aa., and minor sources of blood supply for the head of the pancreas. An anatomical review and radiologic study.

The present article is the fourth part of a comprehensive review of the arterial blood supply of the pancreas and completes the study of the arterial vascularization of the pancreatic head dealing with the anterior inferior and posterior inferior pancreaticoduodenal aa. and with some minor sources of blood supply not involving the classical system of the pancreaticoduodenal arches. The aim of this review is to summarise the anatomical studies, starting from Haller's reports, and to supply, as far as possible with original material, angiographic evidence for the classic anatomical concepts. For this purpose, 1015 selective angiographs (celiac trunk and its branches, superior mesenteric a.) were taken from the angiographic archives of the Institutes of Radiology of Siena, Rome (Catholic University), and Perugia. These demonstrated the anterior inferior pancreaticoduodenal a., present in most instances, as arising from the inferior pancreaticoduodenal a., from a common trunk with the posterior inferior pancreaticoduodenal a. and the 1st jejunal a., from the 1st jejunal a. or from the superior mesenteric a.; on the other hand, the posterior inferior pancreaticoduodenal a. was more variable, originating from the inferior pancreaticoduodenal a., from a common trunk with the anterior inferior pancreaticoduodenal a. and the 1st jejunal a., from the superior mesenteric a., from the dorsal pancreatic a., or from a right accessory hepatic a. coming from the superior mesenteric a. In addition, minor branches to the head of the pancreas arose from the gastroduodenal a., the dorsal pancreatic a., the common hepatic a. and the inferior right phrenic a. Other origins of the inferior pancreaticoduodenal aa. previously reported, but not angiographically detectable with certainty, as well as further minor sources of blood supply to the head of the pancreas, have been listed. The differing opinions regarding the incidence of the various ways the inferior pancreaticoduodenal aa. arise are discussed and an attempt is made to explain the variability of the vascular anatomy of the pancreatic head on embryologic grounds.

Arteries↗
PubMed1996

The arterial blood supply of the pancreas: a review. III. The inferior pancreaticoduodenal artery. An anatomical review and a radiological study.

This article is the third part of a comprehensive review on the pancreatic arterial blood supply and deals with the inferior pancreaticoduodenal a. The aim of this review is to summarise the anatomical studies, starting from Haller's reports, and to supply as far as possible, with original material, angiographic evidences for the classic anatomical notions. For this purpose, the overall research was carried out by picking out and studying 1015 selective angiographies (celiac trunk and its branches, superior mesenteric a.) taken from the angiographic archives of the Institutes of Radiology of Siena, Rome (Catholic University), and Perugia. Angiographically, the authors observed the inferior pancreaticoduodenal a., present in most instances, as arising from the superior mesenteric a., from the right accessory hepatic a., or from a common trunk with the first or the first two jejunal aa. Some variations of the course have been shown. The authors underline and discuss the discordant opinions still existing regarding the incidence of the different ways the inferior pancreaticoduodenal a. arises and the surgical importance of the variation of origin of this artery.

Angiography↗
PubMed1996

The arterial blood supply of the pancreas: a review. II. The posterior superior pancreaticoduodenal artery. An anatomical and radiological study.

The present paper is the second part of a comprehensive review of the arterial blood supply of the pancreas and deals with the posterior superior pancreaticoduodenal artery. The aim of this review is to summarise the anatomical studies, starting from Haller's reports, and to supply as far as possible, with original material, angiographic evidences for the classic anatomical notions. For this purpose, the overall research was carried out by picking out and studying 1015 selective angiographies (celiac trunk and its branches, superior mesenteric a.) taken from the angiographic archives of the Institutes of Radiology of Siena, Rome (University of Sacro Cuore, Catholic University), and Perugia. Angiographically, many possible different sources of the posterior superior pancreaticoduodenal a. (superior pancreaticoduodenal a., proper hepatic a., right hepatic a., left hepatic a., superior mesenteric a., accessory and replaced right hepatic a. coming from the superior mesenteric a.) have been demonstrated, as have rare variations of the course and a small number of collateral branches (retroduodenal a. and ventral commissural a.). Moreover, the authors underline the discordant opinions still existing regarding the incidence of the different ways the posterior superior pancreaticoduodenal a. arises.

Celiac Artery↗
PubMed1996

Transvalvular impedance (TVI) recording under electrical and pharmocological cardiac stimulation.

The cardiac electric impedance was recorded between right atrium and ventricle, throughout the cardiac cycle, by means of a tripolar single pass lead for VDD pacing. The transvalvular impedance signal (TVI) is a sharp periodic wave, with high signal-to-noise ratio, that is detected exclusively in the presence of cardiac mechanical activity. The minimum TVI value is attained during the atrial systole, the maximum at the end of ventricular systole. Different parameters of TVI waveform are affected by changes in the inotropic state, and could therefore be proposed as potential signals for new rate responsive algorithms based on the correlation between inotropic and chronotropic regulation. The signal might be used, moreover, for pacing and sensing validation in autoregulating pacemakers and for fibrillation recognition in ICDs.

Adrenergic Agonists↗
PubMed1996

Down-regulation of evoked synaptic release in rat neuromuscular junction.

Spontaneous and evoked synaptic transmission were studied at the rat extensor digitorum longus (EDL) neuromuscular junction in the presence of CGIIIA mu-conotoxin, a peptide which suppresses action potential in the sarcolemma, while not affecting impulse conduction along motor nerve fibers. The binomial parameters m (mean quantal content) and n (number of units involved in evoked quantal release) increased as a function of extracellular Ca++ ([Ca++]o), up to the physiological concentration (2 mM). Additional Ca++ failed to induce a statistically significant increase in either m or n, while the probability of activation (p) did increase, approaching unity at 4 mM [Ca++]o. In cut EDL preparations, without CGIIIA, the relation between end-plate potential amplitude and [Ca++]o resembled that for quantal content in unlesioned, CGIIIA-treated muscles. In contrast, normal preparations exposed to 0.5 mg/ml d-tubocurarine were much more responsive to Ca++ variations, with a significant end-plate potential amplitude increase in the presence of 4 mM [Ca++]o. However, in curarized preparation the evoked release was remarkably affected by repetitive stimulation, while in the absence of postsynaptic blockers release levels were more stable. We suggest that the stimulatory effect of extracellular Ca++ on evoked release at the mammalian neuromuscular junction might normally be depressed under physiological conditions, possibly by a down-regulation mechanism involving presynaptic nicotinic receptors. Such inhibition would increase nerve transmission efficiency during prolonged motor terminal activity.

Animals↗
PubMed1995

Genetic heterogeneity of beta-thalassemia in southeast Sicily.

In this study we have defined the spectrum of the beta-thalassemia mutations, the beta-thalassemia haplotypes, and the genotype-to-phenotype correlations in a large number of patients with different beta-thalassemia conditions. Seventeen different beta-thalassemia mutations were detected which included one chromosome each with Hb Dhonburi and Hb Lepore. Five alleles, namely, codon 39 (C-->T), IVS-I-110 (G-->A), IVS-I-6 (T-->C), IVS-II-745 (C-->G), and IVS-I-1 (G-->A), account for 90% of all beta-thalassemia mutations in 846 thalassemic chromosomes studied. Haplotyping for a large number of subjects showed that the five common mutations are linked to a few haplotypes. The presence of milder mutations, mainly IVS-I-6 (T C), in about 19% of our patients explains some of the clinical variables. Among the 37 patients with thalassemia of intermediate severity, only 6 were homozygous or compound heterozygous for two severe alleles. The type of beta-thalassemia is the main factor responsible for differences in the phenotypic expression of the disease in patients with Hb S-beta-thalassemia; patients with Hb S-beta(+)-thalassemia are less severely affected than those with Hb S-beta(0)-thalassemia. The five most frequent mutations have comparable distributions all over Sicily.

Fetal Hemoglobin↗
PubMed1995

The arterial blood supply of the pancreas: a review. I. The superior pancreaticoduodenal and the anterior superior pancreaticoduodenal arteries. An anatomical and radiological study.

The gross anatomy of the pancreatic blood supply has been subjected to numerous studies. The results of such studies, however, have never been summarized in detail, even in the most important textbooks. For this reason, a certain confusion was generated, especially regarding the interpretation of the nomenclature used to identify pancreatic arteries. This review summarizes more than two centuries of studies of the gross anatomy of the pancreatic blood supply, clarifies the arterial nomenclature, and underlines the aspects about which anatomists are not in agreement. Moreover, it supplies, as far as possible, documentary evidence for numerous observations previously reported only verbally. For this purpose, more than 200 references were directly consulted to provide the anatomical background of the topic, and more than 1000 angiograms were studied to support the review with original figures. The present paper, on the superior pancreaticoduodenal and anterior superior pancreaticoduodenal arteries, is the first of a series of articles dealing with the pancreatic blood supply.

Aorta, Abdominal↗
PubMed1995

Breast cancer detection with Tc-99m tetrofosmin.

Myocardial SPECT imaging was performed with Tc-99m tetrofosmin. Intense focal uptake at the level of the left breast was observed. At mammography a breast carcinoma was suspected, which was confirmed after surgery. This may be the first report of neoplastic mammary uptake of Tc-99m tetrofosmin.

Breast Neoplasms↗