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Biomedical subjects

R Laschi

Publications and source records attributed to R Laschi.

At least 55 records · Page 3Linked to original sources
PubMed1985

Clinical applications of scanning electron microscopy in gastrointestinal diseases.

We considered the role of scanning electron microscopy (SEM) in clinical investigation of different gastrointestinal diseases. The following clinical applications of SEM may be suggested on the basis of our original data and those reported in literature: in peptic ulcer: assessment of the completeness of healing, by observing the mucosal surface architecture of the scars; identification of mucosal changes, namely enterocytic surface membrane alterations, predictive of recurrence; in coeliac disease: early assessment of the response to gluten-free diet and follow-up of the patients by staging the process of mucosal repair in cerebriform, intermediate and villous patterns; in ulcerative and Crohn's colitis: enhancement of the diagnostic sensitivity of perendoscopic biopsy, by detecting differences in surface structure of mucosa surrounding ulcers in both diseases. This is subverted in ulcerative colitis and preserved in Crohn's colitis. Finally the complementary role of SEM in relation to endoscopy and light microscopy is emphasized.

Adolescent↗
PubMed1985

Use of secondary electron detectors for compositional studies on embedded biological material.

In a scanning electron microscope (SEM) the secondary electron (SE) detector collects SE from various sources (SE-I, SE-II, SE-III) as well as backscattered electrons (BSE). SE-II and SE-III are generated by BSE and therefore provide compositional data. In order to collect the compositional electrons in the SE and BSE signals, we employed specimens with little or no surface morphology. Thin and semithin sections of biological embedded material were utilized, conventionally stained and/or subjected to cytochemical or immunocytochemical procedures. The specimens were observed in a SEM equipped with SE detector (SED), BSE detector (BED) and transmission electron (TE) detector (TED). We drew the following conclusions: a) images by SED of thin sections give the same information as images by TED; b) images by SED of semithin sections provide complementary information with respect to those obtained in BSE and TE mode. Some parameters affecting the intensity and the quality of the signal collected were also considered. Finally we observed the same semithin sections in a transmission electron microscope (TEM) with a SE attachment. Images obtained by SED, BED and TED were fully diversified.

Carotid Arteries↗
PubMed1984

Ultrastructural aspects of duodenal mucosa repair during treatment of peptic disease.

We applied scanning electron microscopy (SEM) to the study of duodenal ulcer healing during treatment with an H2-receptor antagonist (ranitidine). We also evaluated the changes in the duodenal mucosa close to the lesion, which appeared endoscopically and histologically normal. Endoscopic biopsies were taken from 8 patients both on the edge of the ulcer and in the upper duodenum, before and after 1, 2, 3, 4 and 8 weeks of treatment. Endoscopy revealed a decrease of the ulcer crater after the first week and a complete healing after three weeks of therapy. The ulcer edge presented a subtotal mucosal atrophy, cellular exfoliation (dome-shaped cells) and changes in microvilli (bridging, branching, blebs). In the first week of treatment, reepithelization was observed: however, cellular exfoliation and changes in microvilli persisted at least up to the end of the first month of treatment. Short and stumped villi began to reappear after one month. The mucosa farthest from the lesion showed the same alterations but to a lesser extent. The changes tended to decrease after treatment. Two months after the end of treatment the duodenal mucosa was endoscopically and histologically normal, while SEM showed altered microvilli. SEM allowed us to investigate the morphogenesis of mucosal repair and to identify minimal cellular alterations which could represent the morphological basis of the disease and its possible recurrence.

Adult↗
PubMed1983

Relationship between connective tissue cells and fibronectin in a sequential model of experimental hepatic fibrosis.

The cellular and non-cellular components of fibrous septa formed at early and late stages in a sequential model of experimental hepatic fibrosis have been investigated using ultrastructural and immunocytochemical techniques. In the early septa, cells with intermediate features between lobular Ito cells and active fibroblasts were formed. These cells frequently displayed subplasmalemmal microfilaments (myofibroblast-like cells). Macrophages were also present. Scanty typical fibroblasts were present in the late septa. This cellular recruitment might be related to an extracellular glycoprotein-fibronectin-which is at present under investigation as a chemotactic factor for fibroblasts. Strong positivity for fibronectin in early septa and its sharp decrease in late septa seems to support this view. Fibroblasts and/or macrophages are the likely source of fibronectin synthesis.

Animals↗
PubMed1982

Platelets in primary thrombocythemia: electron microscopic study.

The ultrastructural analysis of platelets from patients with Primary Thrombocythemia (PT) showed some anomalous features. Platelets having structural modifications of their organelles were observed and a decrease in the number of dense bodies was seen. Freeze-fracture analysis of the plasma membrane of platelets from PT patients showed a significant increase in the number of intramembranous particles (IMP).

Adult↗
PubMed1981

In vitro culture and ultrastructure analysis of peripheral blood cells separated by discontinuous albumin density gradient during blast crisis of chronic granulocyte leukemia.

Peripheral blood from 4 patients with chronic granulocytic leukemia during blast crisis has been investigated. One case has been studied before and after treatment with Arabinosyl-Cytosine and 6-Thioguanine. The nucleated blood cells have been separated by a discontinuous density gradient. Cells were obtained from six different gradient fractions (F1-F6: density ranging from 1.052 to 1.078). 0.5 X 10(5) cells from each density fraction have been cultured in agar culture system to evaluate the granulocyte-monocyte committed stem cells (Colony Forming Units-granulocyte monocyte: CFU-GM). Cells recovered from the same density fractions have been studied by electron microscopy to evaluate the number of less differentiated cells. A quantitative correlation between plating efficiency and blast cells number was carried out. The results indicate that the highest recovery of both CFU-GM and blast cells is present in light density fractions (specific density below 1.063). However a discrepancy between blast cell frequency and granulocyte-monocyte colony formation in the same density fractions appears to be evident. In the patient studied before and after treatment it appears that only one out of two light density fractions (F1) responds to the antiblastic treatment.

Blood Cells↗
PubMed1981

Angelo Bairati.

Explore the source record for details and available documents.

Cell Biology↗
PubMed1979

Skin storage in liquid nitrogen. An ultrastructural investigation.

The problem of cell survival as well as the biochemical and histological effects on skin of low temperature storage in liquid nitrogen has already received attention. However, little is known of the submicroscopic alterations induced by such treatment. Our study shows that rapid or slow freezing, direct or mediate contact with the liquid nitrogen, pretreatment before freezing, type and concentration of cryoprotectants, all have various effects on the fine morphology of epidermal cells. Glycerol is shown as having better cryoprotective activity than DMSO at concentrations of 15% or less. Our data are examined taking into account all available reports on the problem of cryopreservation and the use of cryoprotectants.

Dimethyl Sulfoxide↗
PubMed1975

An electron microscope study of Darier's disease.

An electron microscope investigation was performed on cutaneous biopsies from four patients with Darier's disease. Suprabasal lacunae with acantholytic cells a prominent feature. Basal cells and acantholytic cells showed an increase in tonofilaments. Corps ronds appeared as vacuolated cells.

Acantholysis↗