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N Dioguardi

Publications and source records attributed to N Dioguardi.

At least 19 recordsLinked to original sources
PubMed2005

Computer-aided morphometry of liver inflammation in needle biopsies.

AIM: To introduce a computer-aided morphometric method for quantifying the necro-inflammatory phase in liver biopsy specimens using fractal geometry and Delaunay's triangulation. METHODS: Two-micrometer thick biopsy sections taken from 78 chronic hepatitis C virus-infected patients were immunohistochemically treated to identify the inflammatory cells. An automatic computer-aided image analysis system was used to define the inflammatory cell network defined on the basis of Delaunay's triangulation, and the inflammatory cells were geometrically classified as forming a cluster (an aggregation of a minimum of three cells) or as being irregularly distributed within the tissue. The phase of inflammatory activity was estimated using Hurst's exponent. RESULTS: The proposed automatic method was rapid and objective. It could not only provide rigorous results expressed by scalar numbers, but also allow the state of the whole organ to be represented by Hurst's exponent with an error of no more than 12%. CONCLUSION: The availability of rigorous metrical measures and the reasonable representativeness of the status of the organ as a whole raise the question as to whether the indication for hepatic biopsy should be revised by establishing clear rules concerning the contraindications suggested by its invasiveness and subjective interpretation.

Adult↗
PubMed2003

[Fractal analysis of liver fibrosis].

This study realized by two different study groups use of Fractal geometry to quantify the complex collagen deposition during chronic liver disease. Thirty standard needle liver biopsy specimens were obtained from patients with chronic HCV-related disease. Three mu-thick sections were cut and stained by means of Picrosirius stain, in order to visualise collagen matrix. The degree of fibrosis was measured using a quantitative scoring system based on the computer-assisted evaluation of the fractal dimension of the deposited collagen surface. The obtained results by both study groups, show that the proposed method is reproducible, rapid and inexpensive. The complex distribution of its collagenous components can be quantified using a single numerical score. This study demonstrated that it is possible to quantify the collagen's irregularity in an objective manner, and that the study of the fractal properties of the collagen shapes is likely to reveal more about its structure and the complex behaviour of its development.

Collagen↗
PubMed2002

Simultaneous staining of cytoplasmic iron and collagen matrix in human liver biopsy specimens.

One of the major liver fibrogenic activators is the cellular iron overload that can severely damage parenchymal and non-parenchymal cells. The aim of this study was to investigate a histochemical staining technique that allows the simultaneous detection of the irregular deposition of matrix collagen and both the amount and distribution of iron in liver cells on the same histological section. The method was evaluated using 3-microm histological sections obtained from ten standard liver biopsy specimens taken from patients with hepatitis C virus-related diseases and simultaneous liver cell iron overload. The results indicate that the double-staining technique is simple, sensitive and rapid, and can be routinely applied to liver biopsy specimens for diagnostic purposes. Furthermore, it may also facilitate the study of the complex relationship between hepatic fibrosis and iron overload during common genetic or secondary liver metabolic disorders.

Biopsy↗
PubMed2001

[Geometrical analysis of benign and malignant breast lesions].

PURPOSE: The aim of this study was to describe a computer-assisted method based on fractal dimension and the coefficient of roundness, two mathematical descriptors of irregularly shaped objects, in order to discriminate benign and malignant mammographic lesions. MATERIAL AND METHODS: Twenty-three digitized mammograms were classified as containing benign lesions (n=12) or as containing malignant lesions (n=11) on the basis of readings by two independent radiologists. Morphometrical and fractal analysis of the breast lesions were automatically performed by a computer-assisted image analysis system. RESULTS: The method shows, for the first time, two parameters that allow the classification of irregularly shaped objects, such as benign and malignant breast lesions. A significant increase was obtained when comparing the fractal dimension and the coefficient of roundness of benign versus malignant mammographic lesions. DISCUSSION AND CONCLUSIONS: Benign and malignant breast lesions are characterized by complex morphologies. Complexity is the main property of all biological systems, including natural and pathological structures. In this study, we showed that fractal geometry allows quantitative measurement of the complex morphology of benign and malignant mammographic lesions. Furthermore, this mathematical approach may be helpful for the study of the non-linear dynamic processes involved in breast carcinogenesis.

Breast Diseases↗
PubMed2001

Fractal geometry: a useful tool for quantifying irregular lesions in human liver biopsy specimens.

Irregularity and complexity are the main features of every biological system, including human tissues, cells and sub-cellular components. These two properties of the organized biological matter cannot be quantified by means of the classical Euclidean geometry, which is able to measure regular object, practically unknown in Nature. The aims of our paper were a) to underline the importance of the shape of a biological structure, b) to investigate the fractal geometry for quantifying the liver histo-pathological structures, and c) to explain the significance of several terms used in the fractal analysis of complex biological systems.

Algorithms↗
PubMed1999

Fractal and spectral dimension analysis of liver fibrosis in needle biopsy specimens.

OBJECTIVE: To evaluate the usefulness of a reliable and reproducible mathematical scoring system based on fractal geometry for quantifying the irregular pattern in fibrosis commonly seen in liver biopsy specimens from chronic liver diseases. STUDY DESIGN: The study used 26 standard liver biopsy specimens obtained from patients with chronic hepatitis C virus-related liver disease. The degree of fibrosis in each specimen was estimated using a quantitative scoring system based on the computer-assisted evaluation of both the fractal and spectral dimensions of deposited collagen. The fractal dimension was then compared with the percent area of collagen measured using an image analysis system. RESULTS: The fractional dimension of its irregular shape defines fibrosis as a natural fractal structure. The complex distribution of its collagenous components (unmeasurable by means of the usual morphometric parameters) can be optimally quantified using a single numerical score that seems to be a better alternative to the semiquantitative methods adopted so far. The proposed method is reproducible, rapid and inexpensive; furthermore, supported by specific software, its mathematical approach excludes subjectivity and eliminates the external factors capable of influencing staging and classification. CONCLUSION: This study demonstrated that it is possible to quantify the irregularity of the structures of the liver in an objective manner and that the box-counting fractal dimension does not depend on the amount of collagen deposited on the slide. Furthermore, as has been found in other fields of investigation, study of the fractal properties of the liver is likely to reveal more about its structure and the pathogenesis of liver diseases.

Biopsy, Needle↗
PubMed1991

Hepatocellular carcinoma in Italian patients with cirrhosis.

BACKGROUND AND METHODS: Patients with cirrhosis of the liver are recognized as being at risk for hepatocellular carcinoma. The magnitude of the risk, the natural history of this disease, and the possibilities for detecting potentially curable tumors in patients in the Western world are unknown. To address these questions, we examined 447 Italian patients with well-compensated cirrhosis (which was of viral origin in 62 percent of them) from 1985 through 1990, performing serum alpha-fetoprotein assays and real-time ultrasonography every 3 to 12 months. RESULTS: Hepatocellular carcinoma was found in 30 patients (7 percent) at base line and in another 29 patients (7 percent of 417 patients free of tumor at base line) during follow-up periods averaging 33 months (range, 1 to 48). The cumulative hazard of the development of hepatocellular carcinoma during follow-up was higher among patients with persistently elevated serum alpha-fetoprotein levels (12 with tumors among 42 with such levels) than among those with fluctuating levels (11 among 82) or those with consistently normal levels (6 among 255). Only 17 patients had potentially operable tumors. The proportion of potentially operable tumors among those detected during follow-up was significantly lower than the proportion at enrollment (4 of 29 vs. 13 of 30, P = 0.027). The survival at one year of the 12 patients who underwent surgery was 67 percent, and the tumor-recurrence rate was 60 percent. Outcome was not appreciably different for the five patients who refused surgery. CONCLUSIONS: In the West, as in Asia, patients with cirrhosis of the liver are at substantial risk for hepatocellular carcinoma, with a yearly incidence rate of 3 percent. Our screening program did not appreciably increase the rate of detection of potentially curable tumors.

Adult↗
PubMed1991

Modeling of biological and medical systems: a systemic strategy.

A strategy in the frame of General System Theory is proposed for the study of biological systems for medical purposes. Its definition and use requires in each experiment the collaboration between physician and system scientists and hence the definition of a common language, by which the real system under study is described. The strategy is based on three intermingled steps: first an ingenuous model is proposed, gathering all the medical knowledge about the studied system, organized within an informal frame derived from the state space approach. Next, a functional model is derived, enlightening the organization of the relations in the medical model. Finally, this organization is formalized by the most suitable algebraic tools, which are thereafter translated into APL programs. This last version is used for simulation, which is exploited not only as a tool to describe and make provisions on the dynamics of the models, but also to deepen and improve the knowledge about the observed system.

Computer Simulation↗
PubMed1990

Atrial natriuretic factor in cirrhotic patients with tense ascites. Effect of large-volume paracentesis.

The plasma levels of atrial natriuretic factor in liver cirrhosis can be affected by various factors, such as ascites, renal function, use of diuretics drugs and dietary sodium intake. Moreover, the influence of high intra-abdominal pressure on cardiac atrial natriuretic factor release in patients with tense ascites has not been investigated. The aim of the present study was to evaluate the circulating levels of atrial natriuretic factor and their relationships to plasma renin activity, aldosterone concentration, and urinary sodium excretion in 45 cirrhotic patients divided into 4 groups: (a) cirrhotics without ascites; (b) nonazotemic cirrhotics with ascites; (c) cirrhotics with ascites and functional renal failure; and (d) cirrhotics with ascites taking diuretics. In some patients with tense ascites, atrial natriuretic factor was also measured after rapid abdominal relaxation by large volume paracentesis. Plasma levels of atrial natriuretic factor obtained in 13 healthy control subjects after 5 days on a 40-50 mEq sodium daily intake were 22.8 +/- 3.3 pg/ml. Mean plasma atrial natriuretic factor levels were normal in patients without ascites (35.1 +/- 11.4 pg/ml) and in those with ascites taking diuretics (27 +/- 9.2 pg/ml), but elevated in patients with ascites not taking diuretics (59.6 +/- 12 pg/ml) and in those with ascites and functional renal failure (58.5 +/- 16.6 pg/ml). These data show that plasma atrial natriuretic factor levels are elevated only in cirrhotic patients who are ascitic and not taking diuretics. In these patients atrial natriuretic factor levels were directly correlated with urinary sodium excretion, even though sodium balance was positive. This could be the consequence of the contrasting effects of antinatriuretic factors, as suggested by the inverse relationships between atrial natriuretic factor and urinary sodium on the one hand and plasma renin activity and plasma aldosterone concentration on the other. Twenty-six patients with tense ascites (12 taking diuretics and 14 not) were treated with rapid large-volume paracentesis (6500 +/- 330 ml of ascitic fluid removed in 168 +/- 16 min). At the end of the procedure, plasma atrial natriuretic factor levels had increased in all patients (from 45.5 +/- 10.1 to 100 +/- 17 pg/ml), whereas plasma renin activity and plasma aldosterone concentration had decreased (from 10.3 +/- 1.6 to 7 +/- 1.3 ng/ml/h, and 1160 +/- 197 to 781 +/- 155 pg/ml, respectively).(ABSTRACT TRUNCATED AT 400 WORDS)

Aldosterone↗
PubMed1989

Prevalence of antibodies to hepatitis C virus in Italian patients with hepatocellular carcinoma.

A sensitive radioimmunoassay was used to detect antibodies to hepatitis C virus (HCV) in patients with hepatocellular carcinoma and chronic hepatitis. HCV antibodies (anti-HCV) were detected in 86 of 132 patients with hepatocellular carcinoma with no relation to the presence or absence of hepatitis B surface antigen (HBsAg). The prevalence of anti-HCV was also high in patients with diseases thought to predispose to hepatocellular carcinoma, such as non-A, non-B chronic hepatitis and cirrhosis (74%). In HBsAg-negative patients with hepatocellular carcinoma the prevalence of anti-HCV was lower than that in patients with non-A, non-B chronic hepatitis (16% vs 55%); the prevalence of serum antibodies to hepatitis B core antigen (anti-HBc), a marker of hepatitis B virus infection, was 70% and 28%, respectively. In HBsAg-negative patients with hepatocellular carcinoma, anti-HCV and anti-HBc occurred together nearly three times as often as in patients with chronic hepatitis (54% vs 19%). These data indicate that, in Italy, HCV is an important factor associated with hepatocellular carcinoma and non-A, non-B chronic hepatitis.

Adult↗
PubMed1989

Beta-blockade prevents recurrent gastrointestinal bleeding in well-compensated patients with alcoholic cirrhosis: a multicenter randomized controlled trial.

To assess the efficacy of beta-blockers in preventing rebleeding in selected cirrhotic patients and to compare the tolerance, safety and patient compliance of a selective and a nonselective beta-blocker, 94 patients were randomly assigned to propranolol (32 patients), atenolol (32 patients) or placebo (30 patients). Randomization was made at least 15 days after the bleeding episode. Propranolol was given orally at increasing doses until the resting pulse rate was reduced by approximately 25%. Atenolol was given at a fixed dose of 100 mg per day. Patients were followed up for a mean of 357 days. Rebleeding occurred in 14 patients in the placebo group, 10 in the atenolol group and eight in the propranolol group. The incidence of rebleeding was significantly lower in patients receiving propranolol than in those on placebo (propranolol vs. placebo: p = 0.01, logrank test). Atenolol was less effective than propranolol (atenolol vs. placebo: p = 0.065, logrank test). Bleeding-free survival was better for patients on active drugs than for those on placebo (propranolol vs. placebo = p = 0.01, atenolol vs. placebo: p = 0.05, logrank test). Retrospective analysis revealed that, whatever the type of treatment, abstinence from alcohol was crucial in preventing rebleeding. We conclude that beta-blocker treatment is effective in preventing rebleeding from esophageal varices in carefully selected alcoholic cirrhotic patients who survive at least 2 weeks after acute variceal hemorrhage and stop drinking.

Actuarial Analysis↗
PubMed1988

[Study of the motivations for balneotherapy. Considerations on the needs of thermal baths users].

After a brief reminder of the dual therapeutic aspect (biological and psychological) of spa treatment, the results are presented of a series of psychological reaction tests (McFarland's Psychosomatic Inventory, the Middlesex Hospital Questionnaire, the Rorschach test) given to a randomized sample of 106 patients together with semistructured interviews conducted by two different psychiatrists. The results show substantial agreement between the motivations volunteered verbally and those revealed by the tests and may be summed up as affective rigidity, impoverished emotional life and difficulty in handling body-related anxieties. It is therefore suggested that it would be useful to create a psychosocial spa centre able to provide global treatment adapted to the specific needs of individual users.

Adult↗
PubMed1984

[Psychological profile of the spa user. Preliminary study of motivations for spa treatment].

The main psychological and possible psychopathological traits of the spa user are identified and classified in order to clarify motivational aspects. Two different self-assessment tests, the Middlesex Hospital Questionnaire (MHQ) and the Minnesota Multiphasic Personality Inventory (MMPI) were given, the first to 500 subjects who had undergone spa treatment cycles lasting at least 10 days and the second to a control group of 50. MHQ data showed a significant incidence of certain neurotic traits, especially phobia, obsession and somatisation in the first group. Despite their different areas of competence and survey methods, both questionnaires produced results to support the hypothesis that a particular form of neurosis may play a significant part in motivating recourse to spa treatment.

Balneology↗
PubMed1983

[Familial hypoalphalipoproteinemia. Vergani's disease].

Deficiencies of lipoproteins occur as genetic disorders or may be presenting features of underlying disease. Familial high density lipoprotein (HDL), or alpha-lipoprotein, deficiency so far described includes Tangier disease, Lecithin: cholesterol acyltransferase (LCAT) deficiency, A-I Variants syndrome and Fish-eye disease. In 1981 Vergani described a familial aggregation of low HDL-cholesterol (less than 33 mg/dl) and Apo A (about 50% of normal levels) in the presence of normal VLDL and LDL-cholesterol. LCAT and lipoprotein lipase activities, both extrahepatic and hepatic, were normal. By zonal ultracentrifugation HDL2 subclass was found to be reduced. HDL apoproteins, examined by isoelectric focusing in polyacrylamide gel, were qualitatively normal. No disorders to which low levels of HDL might be secondary (e.g., overweight, cigarette smoking, nephropathy, liver disease) are present in the affected members. The underlying biochemical defect is unknown but probably involves altered synthesis or catabolism of HDL. Familial hypo-alpha-lipoproteinemia is accompanied by a high prevalence of premature myocardial infarction and sudden death. The genetic analysis of the disorder is consistent with autosomal inheritance. The criteria for the definition of familial hypo-alpha-lipoproteinemia are, therefore, as follows: 1) low HDL-cholesterol level in the presence of normal VLDL and LDL-cholesterol levels; 2) absence of diseases or factors to which hypo-alpha-lipoproteinemia might be secondary; 3) presence of a similar lipoprotein pattern in a first degree relative.

Adult↗
PubMed1983

[Familial alpha lipoprotein deficiency. Tangier disease, familial hypoalphalipoproteinemia and familial deficiency of lecithin cholesterol acyltransferase deficiency].

The plasma lipoproteins are a group of macromolecules all of which transport lipids, including cholesterol, triglyceride and phospholipid, and all of which have one or more protein constituents, called apoproteins. It is becoming apparent that the apoproteins play an important role in lipoprotein metabolism. Recently the so called "alpha hypothesis" has been proposed, according to which a protective role for HDL in atherosclerosis has been postulated. Three "experiments of nature", characterized by deficiencies of HDL as genetic disorders, namely Tangier disease, familial hypoalphalipoproteinemia, familial lecithin: cholesterol acetyltransferase deficiency, support the "alpha hypothesis". The first italian cases with the genetic disorders are presented.

Adolescent↗