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C Tomasi

Publications and source records attributed to C Tomasi.

At least 19 recordsLinked to original sources
PubMed2001

Three months versus one year of oral anticoagulant therapy for idiopathic deep venous thrombosis. Warfarin Optimal Duration Italian Trial Investigators.

BACKGROUND: In patients with idiopathic deep venous thrombosis, continuing anticoagulant therapy beyond three months is associated with a reduced incidence of recurrent thrombosis during the period of therapy. Whether this benefit persists after anticoagulant therapy is discontinued is controversial. METHODS: Patients with a first episode of idiopathic proximal deep venous thrombosis who had completed three months of oral anticoagulant therapy (with warfarin, in 97 percent of the cases and acenocoumarol in 3 percent) were randomly assigned to the discontinuation of oral anticoagulants or to their continuation for nine additional months. The primary study outcome was recurrence of symptomatic, objectively confirmed venous thromboembolism during at least two years of follow-up. RESULTS: The primary intention-to-treat analysis showed that of 134 patients assigned to continued oral anticoagulant therapy, 21 had a recurrence of venous thromboembolism (15.7 percent; average follow-up, 37.8 months), as compared with 21 of 133 patients assigned to the discontinuation of oral anticoagulant therapy (15.8 percent; average follow-up, 37.2 months), resulting in a relative risk of 0.99 (95 percent confidence interval, 0.57 to 1.73). During the initial nine months after randomization (after all patients received three months of therapy), 1 patient had a recurrence while receiving oral anticoagulant therapy (0.7 percent), as compared with 11 of the patients assigned to the discontinuation of oral anticoagulant therapy (8.3 percent; P=0.003). The incidence of recurrence after the discontinuation of treatment was 5.1 percent per patient-year in patients in whom oral anticoagulant therapy was discontinued after 3 months (95 percent confidence interval, 3.2 to 7.5 percent; average interval since discontinuation, 37.2 months) and 5.0 percent per patient-year in patients who received an additional 9 months of oral anticoagulant therapy (95 percent confidence interval, 3.1 to 7.8 percent; average interval since discontinuation, 29.4 months). None of the recurrences were fatal. Four patients had non-fatal major bleeding during the extended period of anticoagulant therapy (3.0 percent). CONCLUSIONS: In patients with idiopathic deep venous thrombosis, the clinical benefit associated with extending the duration of anticoagulant therapy to one year is not maintained after the therapy is discontinued.

Acenocoumarol↗
PubMed2001

Efficacy and safety of out-of-hospital self-administered single-dose oral drug treatment in the management of infrequent, well-tolerated paroxysmal supraventricular tachycardia.

OBJECTIVES: We tested the efficacy of two drug treatments, flecainide (F) and the combination ofdiltiazem and propranolol (D/P), administered as a single oral dose for termination of the arrhythmic episodes. BACKGROUND: Both prophylactic drug therapy and catheter ablation are questionable as first-line treatments in patients with infrequent and well-tolerated episodes of paroxysmal supraventricular tachycardia (SVT). METHODS: Among 42 eligible patients (13% of all screened for SVT) with infrequent (< or =5/year), well-tolerated and long-lasting episodes, 37 were enrolled and 33 had SVT inducible during electrophysiological study. In the latter, three treatments (placebo, F, and D/P) were administered in a random order 5 min after SVT induction on three different days. RESULTS: Conversion to sinus rhythm occurred within 2 h in 52%, 61%, and 94% of patients on placebo, F and D/P, respectively (p < 0.001). The conversion time was shorter after D/P (32 +/- 22 min) than after placebo (77 +/- 42 min, p < 0.001) or F (74 +/- 37 min, p < 0.001). Four patients (1 placebo, 1 D/P, and 2 F) had hypotension and four (3 D/P and 1 F) a sinus rate <50 beats/min following SVT interruption. Patients were discharged on a single oral dose of the most effective drug treatment (F or D/P) at time of acute testing. Twenty-six patients were discharged on D/P and five on F. During 17 +/- 12 months follow-up, the treatment was successful in 81% of D/P patients and in 80% of F patients, as all the arrhythmic episodes were interrupted out-of-hospital within 2 h. In the remaining patients, a failure occurred during one or more episodes because of drug ineffectiveness or drug unavailability. One patient had syncope after D/P ingestion. During follow-up, the percentage of patients calling for emergency room assistance was significantly reduced as compared to the year before enrollment (9% vs. 100%, p < 0.0001). CONCLUSIONS: The episodic treatment with oral D/P and F, as assessed during acute testing, appears effective in the management of selected patients with SVT. This therapeutic strategy minimizes the need for emergency room admissions during tachycardia recurrences.

Administration, Oral↗
PubMed2001

A statistical 3-D pattern processing method for computer-aided detection of polyps in CT colonography.

Adenomatous polyps in the colon are believed to be the precursor to colorectal carcinoma, the second leading cause of cancer deaths in United States. In this paper, we propose a new method for computer-aided detection of polyps in computed tomography (CT) colonography (virtual colonoscopy), a technique in which polyps are imaged along the wall of the air-inflated, cleansed colon with X-ray CT. Initial work with computer aided detection has shown high sensitivity, but at a cost of too many false positives. We present a statistical approach that uses support vector machines to distinguish the differentiating characteristics of polyps and healthy tissue, and uses this information for the classification of the new cases. One of the main contributions of the paper is the new three-dimensional pattern processing approach, called random orthogonal shape sections method, which combines the information from many random images to generate reliable signatures of shape. The input to the proposed system is a collection of volume data from candidate polyps obtained by a high-sensitivity, low-specificity system that we developed previously. The results of our ten-fold cross-validation experiments show that, on the average, the system increases the specificity from 0.19 (0.35) to 0.69 (0.74) at a sensitivity level of 1.0 (0.95).

Adult↗
PubMed2001

[Comparison of clinical and electrophysiologic characteristics of patients with occult and manifest atrioventricular accessory pathway].

BACKGROUND: It is current opinion that concealed and manifest accessory pathways (APs) are indistinguishable with respect to their location and contribution to orthodromic reciprocating tachycardias. The aim of this study was to compare clinical and electrophysiological characteristics of two groups of patients. METHODS: Between January 1999 and June 2000, 42 consecutive patients underwent radiofrequency catheter ablation for paroxysmal atrioventricular reciprocating tachycardia attributable to a concealed AP. Their clinical and electrophysiological characteristics were compared with a group of 48 consecutive patients with manifest AP and supraventricular tachyarrhythmias. RESULTS: There were no differences regarding gender, the prevalence of heart disease and the age of onset of symptomatic tachycardias between the two groups. Compared to those with a manifest AP, the patients presenting with a tachyarrhythmia due to a concealed AP were older (48 +/- 15 vs 40 +/- 16 years, p < 0.05) and had a longer history of tachyarrhythmias (22 +/- 16 vs 13 +/- 13 years, p < 0.05). Atrial fibrillation was more frequent in patients with a manifest AP than in patients with a concealed AP (50 vs 9.5% respectively, p = 0.02). Atrioventricular reciprocating tachycardia was a cause of more hospitalizations (76 vs 35%, p = 0.01) and episodes of pre-syncope (47 vs 22%, p < 0.05) in the group of patients with a concealed AP. The anatomical site of concealed and manifest APs was significantly different: concealed APs were more frequently localized in the left side (93% left, 7% right), while manifest APs were seen in the left side in 64% of cases, in the right side in 29% and in the posteroseptal left + right region in 7% of cases. The retrograde electrophysiological properties and the inducibility of other types of reentrant arrhythmias were similar. Catheter ablation was similarly successful regardless of whether the AP was concealed or manifest, the rates of success being 91 and 88% respectively at the first attempt and with a similar number of energy applications (7 +/- 7 vs 10 +/- 9, p = NS). At a second attempt, the procedure was successful in 100 and 98% of cases respectively. Periprocedural complications occurred in 5% of patients with a concealed (1 ventricular fibrillation, 1 cerebral transient ischemic attack) and in 8% of patients with a manifest AP (2 pericardial effusion, 1 transient atrioventricular block, 1 anginal attack with spontaneous recovery) (p = NS). Complications occurred only for left-sided APs and were independent of the approach (transseptal or retrograde). Relapse of AP conduction was more frequent in the group of patients with a manifest than in those with a concealed AP (12 vs 5%), though not significantly. There were no late complications. CONCLUSIONS: Those patients presenting with a tachyarrhythmia due to a concealed AP, compared to those with a manifest AP, were older and had a longer history of tachyarrhythmia. Atrial fibrillation was more frequent in patients with manifest AP. Atrioventricular reciprocating tachycardia episodes were longer-lasting and caused more hospitalizations and more frequently pre-syncope in the group of patients with a concealed AP. Almost all concealed APs were localized in the left side. The retrograde electrophysiological properties were similar. The results of radiofrequency catheter ablation were comparable in both groups.

Adult↗
PubMed2000

Early exposure to restraint stress enhances chemical carcinogenesis in rat liver.

This study examines the effect of a stress-associated condition on chemical hepatocarcinogenesis in the rat. Rats were given diethylnitrosamine (200 mg/kg. b.w., i.p.), followed, 1 week later, by three cycles of immobilization at room temperature. Two weeks after the last cycle they were treated according to the resistant hepatocyte protocol. At 4 weeks after selection, mean size of glutathione-S-transferase 7-7 positive foci/nodules was increased in the immobilized group (0.82+/-0.22 vs. 0.25+/-0.04 mm(2) in controls). Furthermore, at the end of 1 year 10/13 animals (77%) developed hepatocellular carcinoma in the former group, while only 6/14 (43%) incidence of cancer was found in controls. These results indicate that exposure to restraint stress early during carcinogenesis enhances the development of chemically-induced hepatocellular carcinoma in the rat.

Animals↗
PubMed1999

Fasting-induced apoptosis in rat liver is blocked by cycloheximide.

The effect of cycloheximide (CH) on the fasting-induced changes of rat liver cell and protein turnover has been investigated. Late starvation phase (3-4-day-fasting period) was characterised by a decrease in liver weight and protein and DNA content. The loss of DNA was not related to liver cell necrosis but due not only to depression of cell proliferation as shown by the drop in the labelling index but also induction of apoptosis. This type of apoptosis was documented by the increase in the apoptotic index (cells labelled by TUNEL) and transglutaminase activity as well as by DNA fragmentation. The liver cells of fasted rats appeared smaller as shown by the higher cell density and DNA/protein ratio than in controls. Females were more resistant to fasting-induced apoptosis than males. A single dose of CH, a drug primary known as inhibitor of protein synthesis, induced or enhanced apoptosis in fed and 2-days fasted male rats, respectively, without any sign of cell necrosis. On the contrary, the administration of repeated doses of CH blocked apoptosis induced by fasting. CH "froze" protein and DNA content as well as apoptotic process at the level of 2 days-fasted rats. While fasting-induced liver protein loss resulted from a marked reduction in protein synthesis with a slight decrease in degradation, repeated treatment with CH virtually blocked protein loss by abolishing protein catabolism. These data suggest a direct relationship between the catabolic side of protein turnover and the apoptotic process.

Animals↗
PubMed1999

Effect of fasting/refeeding on the incidence of chemically induced hepatocellular carcinoma in the rat.

Caloric restriction has been associated with a delay in the development of both spontaneous and induced neoplasia. In contrast, cycles of fasting/refeeding were shown by us and others to enhance the incidence of early lesions during chemical carcinogenesis in rat liver. The present, long-term study was undertaken to establish whether such a diffential effect would also extend to the later phases of cancer development, until the overt appearance of neoplasia. Male Fischer 344 rats were initiated with a single dose of diethylnitrosamine (DENA, 200 mg/kg i.p.) and starting 1 week later they were either exposed to three cycles of fasting (3 days) followed by refeeding (11 days) or were fed continuously. Seven weeks after DENA administration the rats were exposed to the resistant hepatocyte model of the liver tumor promotion protocol. All animals were killed 1 year after initiation. Incidence of hepatocellular carcinoma was 2-fold higher in the fasted/refed group compared with the controls (72 versus 36%). In addition, cancers were also larger and of higher histological grade in the former group, with one animal showing metastases to the lungs, while no metastases developed in control animals. Fasting caused a decrease in total liver DNA (from 25.2 +/- 1.1 to 16.5 +/- 1.1 mg after 3 days) which was associated with a decrease in hepatocyte labeling index and mitotic activity and high levels of single cell death (apoptosis). In contrast, a sharp increase in hepatocyte proliferation was observed on day 2 of refeeding and this was more pronounced in glutathione S-transferase 7-7 positive foci compared with surrounding liver (10.2 +/- 2.3 versus 4.6 +/- 0.8%). Such a proliferative wave was associated with a sharp decline in the incidence of cell death. It is concluded that fasting/refeeding performed early after initiation accelerates the development of chemically induced hepatocellular carcinoma in the rat.

Animals↗
PubMed1998

D-dimer testing as an adjunct to ultrasonography in patients with clinically suspected deep vein thrombosis: prospective cohort study. The Multicentre Italian D-dimer Ultrasound Study Investigators Group.

OBJECTIVE: To investigate the efficacy of using a rapid plasma D-dimer test as an adjunct to compression ultrasound for diagnosing clinically suspected deep vein thrombosis. DESIGN: D-dimer concentrations were determined in all patients with a normal ultrasonogram at presentation. Repeat ultrasonography was performed 1 week later only in patients with abnormal D-dimer test results. MAIN OUTCOME AND MEASURES: Patients with normal ultrasonograms were not treated with anticoagulants and were followed for 3 months for thromboembolic complications. SETTING: University research and affiliated centres. SUBJECTS: 946 patients with clinically suspected deep vein thrombosis. RESULTS: Ultrasonograms were abnormal at presentation in 260 (27.5%) patients. Of the remaining 686 patients tested for D-dimer, 88 (12.8%) had abnormal concentrations. During follow up venous thromboembolic complications occurred in one of the 598 patients who were not treated with anticoagulants and who had an initial normal ultrasonogram and D-dimer concentration, whereas thromboembolic complications occurred in two of the 83 untreated patients who had abnormal D-dimer concentrations but a normal repeat ultrasonogram. The cumulative incidence of venous thromboembolic complications during follow up was 0.4% (95% confidence interval 0% to 0.9%). The rapid plasma D-dimer test used as an adjunct to compression ultrasonography resulted in a reduction in the mean number of repeat ultrasound examinations and additional hospital visits from 0.7 to 0.1 per patient. CONCLUSIONS: Testing for D-dimer as an adjunct to a normal baseline ultrasound examination decreased the number of subsequent ultrasound examinations considerably without any increased risk of venous thromboembolic complications in patients not receiving anticoagulants. The use of ultrasound and testing for D-dimer enabled treatment decisions to be made at the time of presentation in most patients.

Biomarkers↗
PubMed1996

A subnecrogenic dose of diethylnitrosamine is able to initiate hepatocarcinogenesis in the rat when coupled with fasting/refeeding.

Caloric restriction causes a generalized decrease in growth rate and has been repeatedly associated with an inhibitory effect on cancer development in several systems. In contrast, exposure to complete fasting followed by refeeding is a metabolic condition associated with increased cell turnover in different organs, including the liver. The present study examines whether such condition is able to sustain the induction of initiated hepatocytes following a subnecrogenic dose of diethylnitrosamine (DENA). Male Fisher-344 rats were fasted for 4 days and 1 day after refeeding they were given a single dose of DENA (20 or 200 mg/kg body wt, i.p.). Negative and positive control groups were fed ad libitum and injected with 20 and 200 mg/kg of DENA, respectively. One week later all animals were subjected to the resistant hepatocyte model for the selection of hepatocyte nodules and they were killed 2 weeks thereafter. Results indicated the presence of gamma-glutamyltransferase (GGT) positive foci and nodules (38 +/- 7/cm2) in rats regularly fed and given 200 mg/kg of DENA, while virtually no focal lesions (< 1/cm2) were found in the group receiving 20 mg/kg of DENA and fed throughout the experiment. However, a significant number of GGT positive foci/nodules (14 +/- 7) also developed in rats exposed to fasting and given 20 mg/kg of DENA 24 h after refeeding. No evidence of hepatocellular necrosis was found in the latter group following DENA administration. No effect of fasting was observed when rats received 200 mg/kg of DENA. It is concluded that fasting/refeeding provides conditions which are able to sustain initiation in rat liver by a subnecrogenic dose of a carcinogen. These findings are in contrast with the commonly reported inhibitory effect of chronic food restriction on various stages of carcinogenesis, including initiation.

Animals↗
PubMed1993

Shape and motion from image streams: a factorization method.

Inferring scene geometry and camera motion from a stream of images is possible in principle, but it is an ill-conditioned problem when the objects are distant with respect to their size. We have developed a factorization method that can overcome this difficulty by recovering shape and motion without computing depth as an intermediate step. An image stream can be represented by the 2F x P measurement matrix of the image coordinates of P points tracked through F frames. Under orthographic projection this matrix is of rank 3. Using this observation, the factorization method uses the singular value decomposition technique to factor the measurement matrix into two matrices, which represent object shape and camera motion, respectively. The method can also handle and obtain a full solution from a partially filled-in measurement matrix, which occurs when features appear and disappear in the image sequence due to occlusions or tracking failures. The method gives accurate results and does not introduce smoothing in either shape or motion. We demonstrate this with a series of experiments on laboratory and outdoor image streams, with and without occlusions.

Journal Article↗
PubMed1990

[Effects of chronic administration of nifedipine on echo-Doppler parameters of left ventricular filling in hypertensive patients].

This study aimed determining the chronic effects of nifedipine (N) on left ventricular filling in 25 patients (mean age 55) with mild to moderate arterial hypertension. M-mode, B-mode and pulsed Doppler measurements were performed at baseline, after 30 min from administration of sublingual N (10 mg) and after 6 months of therapy with slow release N (max dose: 60 mg die). Acute and chronic N reduced significantly both systolic (p less than 0.001) and diastolic pressure (p less than 0.001). At the end of the treatment with slow release N, and septal wall thicknesses had a slight but significant decrease (p less than 0.01). Diastolic and systolic dimension were not modified. Left ventricular mass index decreased significantly from 141 +/- 34 to 130 +/- 31 g/m2 (p less than 0.05). The Doppler-derived diastolic filling indexes (peak E, ratio peak E/A,E deceleration) were abnormal at baseline, and had a significant increase after sublingual and chronic therapy. Changes in left ventricular mass index and diastolic filling indexes were not correlated. A significant correlation was found between peak E changes after acute and chronic N administration (r = 0.732 and p less than 0.001). The results of this study demonstrate that both acute and chronic administration of N modify transmitral flow velocity pattern, suggesting that, in hypertensive patients, left ventricular filling abnormalities are partly dynamic and reversible. Our findings also demonstrate that acute N effects may predict the chronic results.

Adult↗