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Biomedical subjects

G Gasparini

Publications and source records attributed to G Gasparini.

At least 199 records · Page 11Linked to original sources
PubMed1982

A freeze-fracture study of the human nail plate.

This study of freeze-fracture replicas of human nail plate fragments demonstrates that keratin filaments have a width of about 100 A. The 'marginal band' is probably formed by a row of particles, 50 A in diameter, arranged along the inner surface of the plasma membrane. These particles are often masked by keratin filaments. In nonjunctional areas, the plasma membranes are devoid of membrane-associated particles. The only type of junction observed is the desmosome. Even though the modes of keratinization are different, the structures of the keratin pattern, of cell membranes, and of the desmosomes are identical in replicas of wholly keratinized nail and human stratum corneum cells. The ultrastructural differences observed appear to be related to the barrier function carried out by the epidermis and by its desquamation process.

Adult↗
PubMed1982

Freeze-fracture replication technique of human skin.

The freeze-fracture replication technique represents one of the most advanced methods for studying the ultrastructure of biological tissues and has given a new dimension to the ultrastructure research. This technique makes it possible to obtain a cast of a fracture surface of frozen preparations. Apart from allowing samples to be examined without being dehydrated, i.e. under conditions very close to those of living state, it has proved especially useful for the analysis of many tissue functions concerned with membrane activity and exchanges between cells and their disturbance in specific disease conditions. Even through good quality replicas had already been obtained back in 1961 (Moor et al. 1961), only after 1970, mainly thanks to the contribution made by Breathnach and his collaborators (Breathnach et al. 1972, Breathnach 1973, Breathnach et al. 1973) was the freeze-fracture replication technique successfully used in the study of the skin, since this tissue had proved especially difficult to process. In this review paper, technical principles will be summarized and the most important findings so far obtained in the study of normal and pathologic skin will be illustrated.

Cell Membrane↗
PubMed1980

GAp junctions in skin tumors of molluscum contagiosum.

Thin section, tracer, and freeze-fracture experiments demonstrate that the infection caused by molluscum contagiosum virus implies alterations of cellular contacts in the epidermis, never before observed in cutaneous viroses. These changes are basically represented by a distinctive variation in particle packing of gap junctions, a greater proliferation of these junctions and the presence of a high amount of intracytoplasmic gap junctions. Skin tumors caused by molluscum contagiosum virus appear to be a convenient model to study the morphological and topological variations as well as the turnover of gap junctions in the epidermis.

Freeze Fracturing↗
PubMed1980

Internal organization of plasma membranes during the acantholytic process. A freeze-fracture study.

The internal organization of plasma membranes was studied in seven subjects with pemphigus vulgaris and in one subject with familial pemphigus using the freeze-fracture technique. The results obtained seem to suggest that the acantholytic process is produced in a similar fashion whatever the pathogenic agent and that desmosomes represent the "target" membrane specializations in the acantholytic phenomena. The reduction and eventual disappearance of desmosomal particle aggregations is seemingly accompanied by an increase in gap junctions.

Acantholysis↗
PubMed1978

Plasma membranes in psoriatic cells. A freeze-fracture study.

A freeze-fracture study of affected and unaffected psoriatic skin has demonstrated the presence of marked modification of the plasma membrane in the psoriatic lesion. In the lower layers of the epidermis, an increase of membrane associated particles was observed in many keratinocytes, possibly representing the morphological intramembranous equivalent of changes in the outer cell membrane demonstrated with cytochemical techniques. Furthermore, in the malphighian layer, numerous gap junctions have been found, which may be interpreted as a phenomenon compensating the uncontrolled proliferation, and may represent a point of differentiation between cell proliferation in psoriasis and neoplasia. This technique confirmed the poor tendency to adhesion of keratinocytes in extrajunctional areas, which had already been shown by other morphological techniques.

Adult↗
PubMed1975

Ultrastructural changes induced by vinblastine in cutaneous lesions of histiocytosis X.

The ultrastructural examination of the skin lesions of 2 typical patients with subacute disseminated histiocytosis X 12, 24, 36, 48 and 72 hours after the intravenous administration of vinblastine enabled us to observe that, after 12-24 hours, there were numerous Langerhans cells undergoing mitosis which had no spindle microtubules but showed fragments of newly forming nuclear membrane, thus demonstrating that mitosis was arrested in anaphase. Later on, in the Langerhans cells mainly, we observed degenerative phenomena (mitochondrial swelling, perinuclear edema and rupture of the plasma membrane) and, finally, a marked reduction in the number of this type of cells were observed.

Cell Nucleus↗
PubMedDate not supplied

Activity and toxicity of gemcitabine and gemcitabine + vinorelbine in advanced non-small-cell lung cancer elderly patients: Phase II data from the Multicenter Italian Lung Cancer in the Elderly Study (MILES) randomized trial.

BACKGROUND: Following the demonstration that vinorelbine improves survival and quality of life compared with best supportive care in elderly patients with advanced non-small-cell lung cancer (NSCLC), we started the three-arm prospective Multicenter Italian Lung Cancer in the Elderly Study (MILES) trial of vinorelbine, gemcitabine and gemcitabine + vinorelbine. DESIGN: Within the randomized phase 3 trial, pilot single-stage phase 2 studies were planned for gemcitabine and for gemcitabine + vinorelbine. Eligible patients are aged 70 or more, with stage IV or IIIb (with metastatic supraclavear nodes or malignant pleural effusion) NSCLC. Single-agent gemcitabine is given at 1200 mg/m(2) on days 1 and 8; in the combination, gemcitabine is given at 1000 mg/m(2) and vinorelbine at 25 mg/m(2), both on days 1 and 8, every 3 weeks. RESULTS: As planned 49 patients were enrolled in each group. Median age was 74 in both groups. Two-thirds of patients had stage IV disease. The response rate was 18.4% (95% exact CI 8.8-32.0) with both treatments. With single-agent gemcitabine main toxicities were grade 4 thrombocytopenia and grade 2 hepatic toxicity, in one patient each, and grade 2 pulmonary toxicity in two patients. With gemcitabine + vinorelbine combination there were grade 4 neutropenia and thrombocytopenia (one patient each), grade 3 anemia requiring red blood cell transfusion (two patients), and grade 4 fever in two patients. Four patients, with severe cardiac comorbidities, suffered grade 3 heart toxicity with atrial flutter or fibrillation, followed by congestive heart failure responsive to treatment. CONCLUSION: Both single-agent gemcitabine and the gemcitabine + vinorelbine combination are sufficiently active and tolerable to allow continuation of the MILES study.

Age Factors↗