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Biomedical subjects

G Biagini

Publications and source records attributed to G Biagini.

At least 145 records · Page 8Linked to original sources
PubMed1989

[Intrinsic potential of the gingival interdental epithelium and its "therapeutic" induction using brushing. Clinico-morphologic aspects].

Toothbrushing technique may represent an important tool to improve gingival keratinization. Our experience evidenced a close relationship between this endoral therapy and interdental epithelial recovery of gingiva, after two months of treatment. Mechanical or microenvironmental stimuli and genetically determined potentialities are the main factors involved in this clinical-therapeutical recovery to modulate structural epithelial behaviour.

Chronic Disease↗
PubMed1989

Molecular alterations induced by hypertension in pregnancy on syncythiotrophoblast plasma membranes from human placenta.

To evaluate the possible functional relationships between hypertensive status and syncythiotrophoblast plasma membrane behaviour we have carried out a freeze-fracturing and biochemical investigation to assess: 1) ultrastructurally, relations between number and diameter of Intramembrane Particles (IMP) and hypertensive conditions; 2) biochemically, actin content of microvilli in this pathological status. Our data in vitro show a decrease of IMP in hypertension before and after Ca++ addition and a decrease of actin in microvilli of hypertensive placenta. These observations seem to be in agreement with the hypothesis of a possible structural immaturity in hypertensive placenta and may represent morphological signs of placental insufficiency.

Actins↗
PubMed1988

Desmin and actin in the identification of Ito cells and in monitoring their evolution to myofibroblasts in experimental liver fibrosis.

It has been reported that myofibroblasts contain actin and that Ito cells are positive for desmin. The distribution of desmin and actin detected by immunofluorescence, of vitamin A autofluorescence and of Sudan III staining of lipid droplets has been evaluated in sequential stages of experimental liver fibrosis induced in rats by intraperitoneal injections of swine serum. In the normal rat liver Ito cells were positive for desmin and weakly positive for actin. Prior to the development of hepatic fibrosis a clearcut increase in number and desmin staining of lobular Ito cells was observed in treated rats, but the overall actin pattern was unchanged. In the fibrotic rat livers, highly cellular septa contained large numbers of strongly desmin-positive, actin-weakly positive Ito cells and strongly desmin- and actin-positive myofibroblasts. These observations indicate that both Ito cells and myofibroblasts are positive for desmin, but only myofibroblasts contain large amounts of actin. Visualization of actin and desmin using relatively simple techniques, allows the monitoring of Ito cells proliferation, the accumulation of these cells in fibrous septa and their evolution into myofibroblasts as characterized by their increased desmin and actin content; it also allows an indirect evaluation of the process of fibrogenesis.

Actin Cytoskeleton↗
PubMed1988

Biological activity of chitosan: ultrastructural study.

Reparative processes are reconstructive phenomena in which cellular elements and extracellular matrix glycoproteins interact to build the injured tissue. Biomaterials can be used to improve or stimulate reconstruction. In the present experimental investigation, tissue repair induced by chitosan, an 86.8% deacetylated poly(GlcNAc), was monitored by morphological analysis. To evaluate its biological role, chitosan was positioned in contact with dura mater or was used as a dura mater substitute. This polysaccharide, having structural characteristics similar to glycosaminoglycans, seems to mimic their functional behaviour. The inductive and stimulatory activity of chitosan on connective tissue-rebuilding is clearly demonstrated, and it is suggested that chitosan could be considered a primer on which a normal tissue architecture is organized.

Animals↗
PubMed1988

Root curettage and gingival repair in periodontitis.

Twelve patients, aged 35 to 60, having adult periodontitis were treated with scaling and root planning performed with ultrasonic and hand scalers. Biopsies were taken, gingival crevicular fluid and clinical parameters were analyzed at different times, and the healing process was monitored. Findings showed a clear correlation between the amount of crevicular fluid and the histological inflammatory pattern, whereas no relationship between crevicular fluid and gingival pocket depth was apparent. In this study, no differences were found in the histological features of the repair process triggered by either type of scaler.

Adult↗
PubMed1988

Different metastatic aggressiveness by murine TS/A clones: ultrastructure, extracellular glycoproteins and type IV collagenolytic activity.

Cell ultrastructure, extracellular matrix glycoproteins, and type IV collagenolytic activity have been examined in four murine TS/A clones characterized by different metastatic aggressiveness. In vitro, highly metastatic clones (E) exhibited slightly less differentiated ultrastructure, and high type IV collagenolytic activity, while low metastatic clones (F) showed a more differentiated cytotype, with either high and low collagenolytic activity. Type IV collagen, laminin, and fibronectin were expressed without correlation with the metastatic efficiency; keratin was slightly more evident in E than in F cells. The morphological differences between E and F clones were less evident in the tumors produced by subcutaneous injection, and markedly reduced in the relative metastases composed only of the less differentiated cytotype; differences were also reduced in cells cultured on extracellular-matrix-coated flasks. The present study shows that no general correlation is observed between the studied parameters and metastatic aggressiveness.

Adenocarcinoma↗
PubMed1988

Effect of general anesthesia on syncytiotrophoblast plasma membranes from human placenta.

This investigation shows that a general anesthetic produces similar effects in vivo and in vitro. Anesthesia with a barbituric drug, Thiopental, induces an increase in membrane fluidity and a decrease in the activity of acetylcholinesterase in syncytiotrophoblast plasma membranes (SPM) obtained from placentas after caesarean section. The same effects can be reproduced in vitro after anesthetic addition to the isolated plasma membranes. Morphological and freeze-fracturing studies also suggest that membrane protein components are affected by anesthetics.

Acetylcholinesterase↗
PubMed1988

Cytoskeleton and extracellular matrix of cutaneous vessels in inflammatory processes: immunomorphological study.

In pathological conditions, vascular modifications occur in various stages involving both vessel structure and adjacent extracellular matrix. The relationships between vascular cells and surrounding microenvironmental stroma are mediated by cytoskeleton. Our investigation showed a high number of vimentin- and actin-positive cells in the vascular cutaneous bed, mainly related to reactive vascularization phenomena, whereas vessel cells with a desmin-positive reaction were barely detectable. Furthermore, in newly formed vessels ultrastructure showed that basement membrane synthesis strictly depends on close contact between the endothelium and extracellular matrix. Our data give structural evidence of the close morphofunctional interactions existing between vascular cells and extracellular matrix.

Actin Cytoskeleton↗
PubMed1987

Hepatocellular carcinoma: expression of basement membrane glycoproteins. An immunohistochemical approach.

The identification and characterization of collagenous and non-collagenous glycoproteins have made it possible to use specific antibodies as tools for the topographical localization of the various connective tissue components, and thus to follow the progression of parenchymal-stromal interactions. This investigation is an approach to the study of in vivo relationships between basement membrane components (type IV collagen, laminin) and neoplastic cells of hepatocellular carcinoma. Ten cases of hepatic carcinomas were analysed and paraffin-embedded sections were immunostained with anti-laminin and anti-type IV collagen antibodies. The avidin-biotin-peroxidase complex technique was used. In well differentiated neoplasms with hepatic tumour cells organized in a trabecular pattern lined by sinusoid structures, type IV collagen was always detected at the sinusoidal level. Laminin was evident only in two cases with a prominent intraparenchymal vascular bed. In less differentiated neoplasms, sinusoids were almost absent and only large tumour vessels were positive for both laminin and type IV collagen. At the interface between tumour tissue and the surrounding stroma, some carcinomatous elements were surrounded by laminin and type IV collagen. Our data further support the hypothesis that basement membrane phenotypic expression may be influenced both by the degree of tumour differentiation and by the characteristics of the micro-environment.

Basement Membrane↗
PubMed1987

Primary liver cell carcinoma. New insight for a more correct approach to its classification.

Hepatocellular carcinomas, cholangiocellular carcinomas, and "indeterminate" forms have been studied by immunohistochemical detection of several antigens: alpha-fetoprotein and CEA, as well as type IV collagen, laminin, and keratin. While the first two antigens were variably detectable in different samples, in the poorly differentiated areas of hepatocellular carcinoma type IV collagen and laminin were both absent. These basement membrane glycoproteins constantly surrounded the cholangiocellular carcinoma tubular structures and were always present in those areas of the "indeterminate" group where the cells were organized as pseudoglandular or ductular aggregates. Keratin was absent in all cases of hepatocellular carcinoma, was variably detectable in the "indeterminate" neoplasms and was always present in cholangiocellular tumors. The neoplasias with mixed histopathological features usually showed morphological and biochemical biliary differentiation at the periphery, in contact with the collagenous stroma. We postulate that in some cases hepatocarcinoma cells undergo metaplastic transformation giving rise to cholangiocellular forms. Type IV collagen, laminin, and keratin seem to be accurate markers of phenotypical differentiation and show that a continuous phenotypical spectrum exists between hepatocellular and cholangiocellular entities.

Adenoma, Bile Duct↗
PubMed1987

Immunohistochemical study of basement membrane antigens in bronchioloalveolar carcinoma.

Bronchioloalveolar carcinoma (BAC), not yet completely defined as a biologic entity, has recently been classified into two different types. Immunohistochemical investigations, aimed at characterizing basement membrane (BM) behavior in the two types of BAC, revealed different distribution patterns. The first (Type I BAC) showed a linear staining for laminin and Type IV collagen similar to normal lung. Fibronectin was widely present in the septal interstitium and patchily distributed along the BM. The second (Type II BAC) showed a variable reaction for Type IV collagen and fibronectin, whereas laminin was absent or appeared as short, interrupted tracts around the epithelial neoplastic population, similar to conventional adenocarcinoma of the lung. These results suggest that only Type I BAC shows structural characteristics different from those of conventional adenocarcinoma of the lung.

Adenocarcinoma↗
PubMed1986

Behaviour of basement membrane antigens in gastric and colorectal cancer. Immunohistochemical study.

Eighty gastric and colorectal lesions including cases of dysplasia and carcinoma were studied by immunohistochemical techniques to investigate the behaviour of laminin, type IV collagen and fibronectin. Their distribution was examined on frozen and formalin-fixed, paraffin-embedded samples. In the same lesions, interruption, fragmentation and absence of basement membrane (BM) antigen-staining were observed. Carcinomas with well differentiated glandular structures were always surrounded by a well defined BM as in normal, non-pathological tissues. On the contrary, undifferentiated areas arranged in nests or sheets were usually negative for laminin and type IV collagen. Anomalous BM staining was strictly related to the degree of differentiation of tumor tissue, while no correlation existed between carcinoma staging and BM antigen presence, either in gastric or colorectal neoplasms. Immunostaining with antibody against type IV collagenase showed a massive positivity in the early gastric carcinomas examined, while in colorectal cancer only granulocytes showed it.

Antigens↗
PubMed1986

Fibronectin distribution during lymph node development in guinea pig: an immunohistochemical study.

We carried out an immunohistochemical study on mesenteric guinea pig lymph nodes, from the 10th day prepartum till the 26th day postpartum, to assess the role of fibronectin in their organization during development. This glycoprotein is diffusely distributed in embryonic lymph nodes, suggesting a primer function during organogenesis. After birth, in fact, it is less widespread and is mainly localized around sinuses and vessels. Our data, supporting the important role of this glycoprotein during lymph node organization, are in agreement with the results obtained in other tissues and organs.

Animals↗
PubMed1986

Detection of extracellular matrix antigens (fibronectin, laminin, type IV in collagen) in paraffin embedded sections by avidin-biotin-peroxidase complex labelling.

An avidin-biotin-peroxidase labelling method was applied to frozen sections and to routine-fixed, paraffin-embedded sections, and compared with immunohistochemical results of stromal antigen detection (type IV collagen, laminin and fibronectin) obtained in parallel on different neoplasias. Lung, breast and gastrointestinal tract tumors were studied. Superimposable sections were obtained from cryostat and formalin-fixed, paraffin-embedded specimens (previously digested by pepsin). The data demonstrate the potential use of immunohistochemical investigation of paraffin-embedded tissues for histological analyses of tumors.

Avidin↗