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Biomedical subjects

F Grizzi

Publications and source records attributed to F Grizzi.

14 recordsLinked to original sources
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

Rapid induction of cytotoxic T-cell response against cervical cancer cells by human papillomavirus type 16 E6 antigen gene delivery into human dendritic cells by an adeno-associated virus vector.

We have shown that the pulsing of dendritic cells (DCs) with human papillomavirus type 16 (HPV-16) antigen proteins by lipofection stimulates class I-restricted cytotoxic T lymphocyte (CTL) response against primary cervical cancer cells. Also, we have shown that adeno-associated virus (AAV) was able to effectively deliver a cytokine gene into DCs. It has been our hypothesis that the delivery of antigen genes into DCs, resulting in endogenous and continuous antigen protein expression, may result in an improvement in T-cell priming by DCs. Here, DCs are pulsed (infected) with an AAV vector containing the HPV-16 E6 gene. After infection, transduced E6 gene mRNA expression and vector chromosomal integration could be identified in infected DCs. Furthermore, priming rosettes formed at early times when the AAV/E6 vector was used. Most importantly, AAV/E6 vector pulsing of DCs induced, after only 7 days of priming, a strong CTL response against primary cervical cancer cell lines, compared to bacterial E6 protein lipofection. Killing was significantly blocked by the addition of anti-MHC class I antibodies. Fluorescence-activated cell sorter (FACS) analysis of resulting primed cell populations revealed higher levels of CD8+ T cells by AAV-based pulsing, with little evidence of CD56 (NK). FACS analysis of the DC populations revealed that AAV/E6 vector-pulsed DCs had higher levels of CD80 and lower levels of CD86 than protein-pulsed DCs. These data suggest that rAAV may be appropriate for antigen pulsing of DCs for immunotherapy protocols. Finally, our protocol represents an advance in regards to the time needed for generating a CTL response compared to other techniques.

Cytotoxicity, Immunologic↗
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↗
PubMed2000

Fractal analysis.

Explore the source record for details and available documents.

Cell Nucleus↗
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↗
PubMedDate not supplied

Mast cell density, hepatic stellate cell activation and TGF-beta1 transcripts in the aging Sprague-Dawley rat during early acute liver injury.

Mast cells (MCs) have been indicated as a source of various inflammatory cytokines, chemokines and growth factors. This study evaluates liver tissue MC density as a quantitative marker of acute liver inflammation in 2- and 19-month old rats treated with carbon tetrachloride (CCl4) toassess the relationships between MC density, hepatocellular damage, mRNA encoding TGF-beta1, hepatic stellate cell (HSC) activation and collagen levels. Consecutive histological sections from each age group were stained with toluidine blue to identify granulated MCs, Direct Red 80 to recognize collagen matrix, and by immunohistochemistry to identify activated hepatic stellate cells (HSCs), which were subsequently counted by means of a computer-aided image analysis. Histology showed hepatocellular necrosis with inflammatory cell infiltration and collagen matrix deposition. Two and 24 hours after intoxication, MC density had considerably increased in the younger rats, but less in those aged 19 months. Although the untreated older rats had a larger area occupied by activated HSCs than the untreated younger rats, the increase in the number of HSCs was greater in the younger rats both two and 24 hours after intoxication. The greater MC density in younger rats suggests that older rats have a reduced immune response or recruit fewer MCs. The activated HSCs and TGF-beta1 transcripts did not increase significantly during the study period, thus indicating that these are later events in chemically induced hepatic toxicity. In conclusion. MC density may be an index of acute liver inflammation after CCl4 intoxication.

Aging↗