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Biomedical subjects

M T Pieraggi

Publications and source records attributed to M T Pieraggi.

At least 55 records · Page 3Linked to original sources
PubMed1987

[Repair of the connective tissue in a non-sutured skin wound].

During the healing of a second intention wound, granulation tissue is built up during the inflammatory and detersive phase which commences in the wound edges as soon as the loss of substance is created. Granulation tissue becomes scar tissue via connective and vascular proliferation and epidermization takes place concurrently. The origin of the fibroblasts composing the granulation tissue is debated: monocytes or fibroblasts from the wound edges? Ultrastructural and immunohistochemical data from studies of experimental wounds in the pig and the monkey make it possible to determine their origin and follow their progress. These cells originate from the fibroblasts of the wound edges and become undifferentiated cells which multiply and migrate to reach the loss of substance. There they become activated fibroblasts and contribute to repairing the loss of substance by secreting fibronectin and type I and type III collagen. As differentiated fibroblasts and myofibroblasts, they remodel and contract scar tissue.

Acute-Phase Reaction↗
PubMed1986

An unusual dermal collagen disorder in a dog.

An adult dog developed a connective tissue disorder characterized by hyperextensibility of the skin on the head, neck and shoulders. Under light microscopy, the thickness of the dermis was reduced and the collagen bundles were fragmented. Hypodermic lesions appeared as fat necrosis and swelling of the wall of the blood vessels. Electron microscopically, the packing of collagen bundles and fibres in the dermis was highly disorganized and the rough endoplasmic reticulum of fibroblasts showed dilatation of the cisternae. Whereas the dermal lesions were non-specific, this case differed fundamentally from canine inherited collagen diseases in that the clinical features appeared in an old dog and the dermal lesions were only localized and were associated with hypodermal atrophy.

Animals↗
PubMed1985

[The fibroblast].

The fibroblast, major cell of connective tissue, secretes the various elements of interstitium: collagens, proelastin, glycoproteins and proteoglycans. It maintains the turnover of these structures and intervenes, also, in the cholesterol LDL metabolism. These various properties explains its different morphological aspects. In young patients, it is an active secretory cell. Its voluminous cytoplasm contains a well developed endoplasmic reticulum and others organelles. It is always in close connection with collagen fibers. The cytoskeleton consists of a fine network visible throughout the cytoplasm and near of secretory areas. In adult patients, the fibroblast keeps the same characteristics, but the endoplasmic reticulum is poorer than in young subjects. In old patients (physiologic or pathologic ageing) it becomes a quiescent cell. It is a flattened cell; its cytoplasm contains a poorly developed endoplasmic reticulum and numerous dense bodies. Its cytoskeleton is characterized by voluminous fascicles or bundles of microfilaments into large cytoplasmic areas. This modified fibroblast has not direct contact with collagen. In all cases, various stimuli can: activate the fibroblast. Then this cell becomes a large cell with very abundant reticulum endoplasmic, ribosomes, polysomes, and numerous secretory vesicles. It is an active secreting cell; becomes fibroblast and; change into myofibroblast by presence of myofilaments in its cytoplasm.

Actin Cytoskeleton↗
PubMed1984

Fibroblast changes in cutaneous ageing.

With ageing there are progressive modifications in the connective tissue of the dermis. In ten young subjects the collagenous bundles are thick and the fibroblasts are active cells in close contact with collagen fascicles. In ten elderly subjects collagen fibres are fragmented and the fibroblasts are quiescent, without any contact with collagen. In ageing the most important lesion is the destruction of the relationship between fibroblasts and interstitial matrix. A role for fibronectin in this adhesion is suggested: in old subjects the papillary network of fibronectin is poorly developed. Furthermore, in the fibroblast we can see architectural changes in the cytoskeleton; this modification breaks up the cytoskeleton - plasma membrane - fibronectin unit and explains the secretory and metabolic changes observed in ageing, the dysfunction of the cell-interstitial matrix unit, and also the structural changes.

Adolescent↗
PubMed1984

Dermis ageing.

On ageing major changes within connective components of the dermis can be seen: collagen looses its regular and fascicular appearance, while ground substance increases, elastic material decreases and the fibroblast cell population becomes "at rest". The resulting dermal ageing is different according to individuals and is related to genetic back ground and exposition to multiple aggressions. This review presents these changes of the superficial dermis and the role of fibroblasts in the conservation of the connective tissue integrity.

Adult↗
PubMed1984

Skin, hair and nail changes in a case of citrullinemia with late manifestation.

We report the case of a 56-year-old woman with a history of episodes of vomiting and coma. Hyperammoniemia , hypouremia , hypercitrullinemia and the decreased arginino -succinic synthetase activity on skin fibroblast cultures permitted us to diagnose citrullinemia. We think that the skin changes, i.e. atrophy of the epidermis, thin and short collagen bundles, dystrophic elastic fibers, increased fundamental matrix, were due to the undernutrition state and were not specific. The dosage of the amino acids of the total skin showed a decreased hydroxylation of lysine in the insoluble fraction, and the presence of proline and hypdroxyproline in the soluble fraction. These metabolic changes were not specific and evidenced the disorganization and the lysis of the connective tissue due to the under-nutritional state. The nail changes, i.e. clubbed fingers and 'half-and-half nail' syndrome, were not specific either. The hair changes mentioned by other authors in newborns and young children, i.e. sparse and brittle blond hair, presence of transverse opaque bands ('irregularly banded hair'), were not present in our case. We only found changes in the cuticle and some trichorrhexis which were not specific of the disease either.

Age Factors↗
PubMed1982

[Localization of apoprotein B in human dermis. A study using optical and electronic immunoprocedures].

The structural localization of apo B, the major protidic constitute of low density plasma lipoproteins, was investigated in human dermis using an immunofluorescence procedure and an immunoperoxidase technique. Apo B was found attached to plasmic fibroblast membranes and along collagen fibers. Dermal areas containing apo B were more numerous in patients with coronary disease than in subjects of the same age with healthy coronary vessels. These results are consistent with those of biochemical determinations: concentrations of apo B in the aorta and skin are parallel and vary according to the severity of atheromatous lesions.

Apolipoproteins↗
PubMed1982

Striae: morphological aspects of connective tissue.

The study of 15 abdominal striae in women aged 25 to 57 shows important histological modifications in the skin. The collagen is fragmented and the ground substance is abundant. Fibroblasts are globular, quiescent, and lose all signs of fibrillar secretion. In the light of the recent biochemical data, our results suggest that the striae are the consequence of fibroblastic dysfunction, due to abdominal distension. Comparison with scarred and normal skin indicate that striae are a special entity belonging to the group of connective dystrophies.

Abdomen↗
PubMed1982

[D-Penicillamine effect on collagen synthesis and structural maintenance Red Sirius staining with polarized-light examination. The value of this staining in cases of collagen diseases (author's transl)].

A severe systemic sclerodermia has been treated by D-Penicillamine. A pathological study before and after treatment showed important changes of the collagen structure. The soluble or foetal collagen fraction is enhanced. By the Red-Sirius staining with polarized light examination of the bundles of foetal collagen are green and bright. Then, this staining appears as a marker of collagen structures.

Adult↗
PubMed1982

The effect of beta-aminoproprionitrile on the lingual artery and aorta of the rat: a light microscopic study.

The effects of chronic toxicity of beta-aminoproprionitrile (BAPN) on the lingual artery and aorta of the rat were compared. Thirty-two three week old weanling male white Wistar rats were given 1 g/kg/day (for five days weekly) of a 40% saturated solution of BAPN fumarate by intragastric tube. The animals were divided into four groups of eight animals each and sacrificed after one, three, six and nine weeks respectively. For each group, four controls were used. Cross-sections of the lingual artery and aorta stained with hematoxylin-erythrosin-safranin, alcian blue, Masson's trichrome and Verhoeff's iron hematoxylin were studied. BAPN had no effect on the lingual artery. Early changes were seen in the aorta at six weeks. Characteristic lesions were found at nine weeks involving the elastic tissue, myocytes and ground substance. The elastic lamellae were thinner, lost their normal orientation, and became swollen and finally fragmented. The myocytes of the media changed orientation and migrated into the intima. The proteoglycans increased and fibrosis supervened at the end stage. Failure to induce lesions in the lingual artery may be explained by early structural maturation and a low metabolic turnover rate in muscular arteries, decreased exposure to or greater protection from mechanical stress.

Aminopropionitrile↗