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F Franceschini

Publications and source records attributed to F Franceschini.

At least 55 records · Page 3Linked to original sources
PubMed1990

Characterization of different microenvironments at the surface of the frog's taste organ.

We used a panel of histochemical techniques to identify and characterize the cell-associated extracellular material at the surface of the frog's taste organ. We employed morphological and histochemical techniques using both the light microscope and the electron microscope. Results show that the apical, external aspect of cells reaching the surface of the taste organ is in close contact with a layer of amorphous material. The histochemical characteristics of this material vary according to the cell type with which it is in contact. Three different microenvironments can be identified at the surface of the frog's taste organ: type 1 microenvironment is associated with the superficial layer of mucus (secretory) cells; type 2 microenvironment characterizes the surface of the so-called wing cells, which reach the surface of the taste organ as thin laminae running among mucus cells; and type 3 microenvironment shrouds the free endings of putative taste cells and is rich in calcium and lipids. Type 2 and type 3 microenvironments fix peroxidase (a sapid macromolecule) with increasing affinity. We conclude that highly differentiated microenvironments exist at the surface of the frog's taste organ, and these could play a role in the chain of biological events leading to the taste sensation. Furthermore, characterization of the cell-associated, specific microenvironments can help clarify the role of the different cell types in the frog's taste organ.

Animals↗
PubMed1990

Morphometric evaluation of intracytoplasmic lipid in normal and pathological parathyroid glands.

The chief morphological criterion for classifying parathyroid glands as 'normal', 'suppressed', or 'activated' is the lipid content of the cytoplasm. In particular, cytoplasm lipid deposit is scanty in the active parathyroid cell, according to many authors. In this paper we present the results of a morphometrical study of ten normal parathyroid glands from patients undergoing thyroidectomy, 20 enlarged 'adenomatous' glands from patients with primary hyperparathyroidism, and 20 glands of normal size from the same hyperparathyroid patients. We aimed at assessing the content of intracytoplasmic lipid of secretory cells in all these conditions. The results show that secretory cells of adenomatous glands have less lipid than those from normal glands; however, there was considerable overlapping of the data in the two groups. The mean lipid content of cells in glands of normal size taken from hyperparathyroid patients was not significantly different from the mean value of normal cells, even when ultrastructural evidence of activation was present in the former. These data suggest that caution has to be exercised in assessing the functional status of parathyroid glands on the basis of lipid content of secretory cells, mainly when differentiating between adenoma and hyperplasia.

Cytoplasm↗
PubMed1990

The chemoreceptor surface of the taste disc in the frog, Rana esculenta. An ultrastructural study with lanthanum nitrate.

The distribution of lanthanum on the taste disc of the frog, Rana esculenta, after en bloc staining of the tongue with lanthanum nitrate was studied at the ultrastructural level by means of scanning electron microscopy (in the secondary electron mode or in the back scattered electron mode), energy-dispersive X-ray microanalysis, transmission electron microscopy and electron spectroscopic imaging. It was consistently found that lanthanum distribution on the surface of the taste disc is not homogeneous and that the surface of putative receptor cells is in contact with strongly lanthanum-positive material. Calcium co-localizes with lanthanum at that level. These results suggest that different microenvironments exist at the surface of the taste disc and that this could be relevant to the receptor function.

Animals↗
PubMed1990

Prevalence, clinical, and laboratory features of thrombocytopenia among HIV-infected individuals.

Prevalence and clinical features of human immunodeficiency virus (HIV)-related thrombocytopenia have been investigated among a random population of 657 anti-HIV-positive individuals. A platelet count below 100 X 10(9)/liter was detected in 72 patients (10.9%). Compared with anti-HIV-positive controls with normal platelets, a significantly higher prevalence of males (p less than 0.02) and of intravenous drug abusers (p less than 0.02) as well as a higher frequency of patients with advanced HIV-related disease (p less than 0.001) were detected among thrombocytopenic patients. Those patients whose thrombocytopenia was associated with neutropenia and/or anemia (14 cases, 2.1%) clearly differed from patients with isolated thrombocytopenia (IT) (58 cases, 8.8%) since they belonged to the more advanced groups of the CDC classification of HIV-related disorders, had lower CD4-positive lymphocyte counts, a higher frequency of cutaneous anergy, and less persistent thrombocytopenia. In the cohort of patients with persistent IT (47 cases), no single epidemiological or clinical data proved to correlate with the severity of thrombocytopenia. They did not differ significantly from anti-HIV-positive controls in their distribution among CDC groups, but the total lymphocyte and the CD4-positive lymphocyte counts were significantly lower in IT patients belonging to CDC group II (p less than 0.05 and p less than 0.02, respectively) and III (p less than 0.01 and p less than 0.005, respectively) compared with CDC group-matched controls; after a median followup of one year, the two cohorts showed similar rates of progression to CDC Group IV.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Allo-activated CD4+ and CD8+ lymphocyte subsets: new ultrastructural findings based on computer-assisted image analysis.

Primary allo-stimulation induces substantial and differentiated modifications in the development of cytoplasmic organelles of peripheral T-lymphocyte subsets. The present computer-assisted image analysis provides evidence that the CD4+ subset undergoes significant increase in organelle density after stimulation, while the CD8+ subset exhibits a post-stimulation organelle development proportional to the cell size. Each immunological subset contains two distinct patterns of cytoplasmic organization, here defined as type I (containing a few cytoplasmic organelles) and type II (with well-developed synthesis and storage organelles). On the basis of these findings cytologic parameters could be ascribed to a heterogeneous proliferation of functionally distinct T-cell clones in CD4+ and CD8+ subsets.

CD4-Positive T-Lymphocytes↗
PubMed1990

An ultrastructural study of normal human thymic epithelium in primary cultures.

The ultrastructural study of a large series of samples of normal human thymic epithelial cells (TECs) in primary cultures is here presented. Cultured TECs are heterogeneous due to marked differences in their cytoplasmic organization. In particular, a spectrum of ultrastructural features have been observed, ranging from poorly-differentiated cells to secretory and epidermoid-like ones, as well as intermediate transitional forms and cells co-expressing both epidermoid-like and secretory features. Cells with peculiar secretory (neuroendocrine-like) characteristics have also been identified in the culture obtained from one of the donors. These data suggest the existence of a thymic epithelial cell type which may act as a dynamic unit, changing its cytoplasmic organization in response to microenvironmental signals. The types and interrelationships of cytoplasmic organelles observed in the secretory cells suggest that the production of thymic peptides involves the classical pathway of protein synthesis and secretion.

Cell Differentiation↗
PubMed1990

Decreased number of peripheral blood CD4 + CD29+ lymphocytes and increased in vitro spontaneous production of anti-DNA antibodies in patients with active systemic lupus erythematosus.

Flow cytometric 2-color analysis of peripheral blood lymphocytes from patients with systemic lupus erythematosus (SLE) showed a reduction of relative and absolute number of CD4+ CD29+ cells compared to matched healthy individuals. This abnormality was more marked in patients with active/very active disease. Absolute number of CD4+ CD29+ cells was negatively correlated with spontaneous anti-DNA Ig production that we demonstrated to be a laboratory index strongly correlated with a clinical disease activity score. A decrease of the percentage of CD8+ CD29+ lymphocytes in patients with active disease was also observed.

Adult↗
PubMed1989

The "lamellated" skull in beta-thalassaemia.

The skull in homozygous beta-thalassaemia may present several abnormalities, such as osteopenia, widening of the diploic space, and a "hair-on-end" appearance. In some cases it presents also a particular stratified appearance caused by a variable number of osseous lamellae, parallel with the inner table. This "lamellated skull" was observed in 16 out of 150 patients affected by the disease (10.6%). Possible mechanisms are discussed. The lamellar osseous changes could be due to repeated periosteal osteoblastic reactions to the sinusoidal neovascularization associated with marrow hyperplasia in poorly transfused patients.

Adolescent↗
PubMed1989

The radiographic appearances following adequate transfusion in beta-thalassaemia.

The main lesions of the skull and hand, observed in a group of hypertransfused beta-thalassaemic patients, are compared with a control group of low-transfused patients. Bony abnormalities reflect the relationship between proliferating bone marrow and bone cortex, and hypertransfusion therapy will prevent development of lesions only if established early in life. If this is done, the diploë in the skull may become normal, overgrowth of facial bone is moderate, pneumatisation of the paranasal sinuses is not completely prevented, and the "hair-brush" pattern may disappear completely. A normal appearance of the hand in adequately treated patients differentiates between prepubertal patients and adults.

Adolescent↗
PubMed1989

Absence of a correlation between T lymphocyte subsets and clinical activity in relapsing-remitting multiple sclerosis.

Cytofluorographic analysis of CD3+, Tac+, HLA-DR+ peripheral blood lymphocytes and CD4/CD8 ratio was performed monthly, over a 10-month period, in a group of 16 patients with multiple sclerosis (MS). No correlation was found between clinical relapses and fluctuations in the lymphocyte subsets, although patients who were in remission throughout the study showed a number of CD3+ cells and a CD4/CD8 ratio significantly lower than those in normal controls. We concluded that changes in peripheral blood lymphocyte subsets are not related to the disease process and their measurement is not helpful in monitoring the illness.

Adult↗
PubMed1989

Antinuclear antibodies in psoriatic arthritis and its subgroups.

We tested serum samples from 48 patients with Psoriatic Arthritis (PA) for Antinuclear Antibodies (ANA) using a highly sensitive substrate (Hep-2 cells). We obtained the following results: 1) in PA patients ANA positivity (16.6%) was significantly higher than in age-and sex-matched groups of healthy controls (4.1%; p less than 0.05) and uncomplicated psoriasis (2%; p less than 0.025). 2) ANA were more common in Symmetrical Polyarthritis (37.5%) and Arthritis Mutilans (25%) than in Asymmetrical Oligoarthritis and Spondarthritis (11.8%) and 'Classical' PA (0%). 3) We did not find any positivity for anti-DNA and anti-ENA antibodies among PA patients.

Adult↗
PubMed1989

Basal cells of the frog's taste organ: fluorescence histochemistry with the serotonin analogue 5,7-dihydroxytryptamine in supravital conditions.

We utilized the fluorescent serotonin analogue 5,7-dihydroxytryptamine (5,7DHT) to visualize basal cells in the frog's taste organ in supravital conditions. In whole mounts of lingual mucosa, specifical and detailed morphological visualization of fluorescent basal cells was obtained in the peripheral and central region of the intact taste organ; similar results were obtained after mechanical dissociation. Preincubation with serotonin prevented any fluorescence in basal cells. Electron microscopy showed good preservation of the ultrastructural morphology of the taste disk after exposure to 5,7DHT. The advantages of the current method as compared with conventional ones are discussed. This simple, reliable procedure will be useful to further define the biology of neuroendocrine cells in taste as well as in other organs.

5,7-Dihydroxytryptamine↗
PubMed1988

Circumscribed lytic lesions of the thalassaemic skull.

Solitary or multiple circumscribed osteolytic areas are described in seven patients, selected from 250 patients with homozygous beta-thalassaemia (Cooley's anaemia). On X-ray examinations, these areas appear as purely osteolytic lesions with well-defined margins not associated with sclerosis. The possible mechanisms are discussed.

Adolescent↗
PubMed1988

[Thalassemia today. The radiologic evolution of lesions of the skull and hand with reference to transfusion therapy].

The main abnormalities of the hand and skull in a group of patients who underwent hypertransfusion regimen were reviewed and compared to the lesions observed in a control group of low-transfused patients. The results are reported, and a possible correlation with transfusion regimen is discussed: since bone lesions are explained on the basis of relationship between proliferating bone marrow and bone cortex, hypertransfusion regimen will prevent the development of abnormalities, only if established early in life. For this reason, skeletal lesions in Cooley's anaemia have changed their "classical" radiographic patterns. In the skull, the diploic space may become normal, and the overgrowth of facial bones moderate; the pneumatization of paranasal sinuses may not be completely impeded by the swelling of the jaws, the "hair-brush" pattern may disappear completely. The normalized picture of the hand is and remains a typical differential sign of prepuberal and adult patients.

Adolescent↗
PubMed1988

The fine morphology of the basal cell in the frog's taste organ.

We investigated the fine morphology of basal cell in the frog's taste organ by means of transmission electron microscopy. Results show that basal cells are placed at the base of the disc and are highly polarized; the cell body is peripherally located and a long cell process reaches the central region of the taste disc without branching. The cell body contains the nucleus, the Golgi apparatus and large lysosomes; junctions between more peripherally located 'marginal' cells prevent passage of macromolecules from oral ambient to basal cells as shown by horse-radish peroxidase experiments. The cell process, running just over the basement membrane in the taste disc epithelium, is rich in microtubules, filaments and clustered secretory granules arranged near the plasmalemma. Nerves interrupting the basement membrane make synaptic-like junctions with basal cells. The cell process ends in the central region of the taste disc; here, the basal cell is expanded to contain filaments, secretory granules and mitochondria in characteristic arrangement and contacts intraepithelial nerve endings as well as basal processes of sensory and supporting cells. Marginated granules are found where basal cell contacts nerve ending and also where nerve and sensory cells contact basal cell. Our findings are consistent with the hypothesis that basal cells are under nerve control and that they may have a diffuse (paracrine) influence on neighbouring cells in the frog's taste organ.

Animals↗
PubMed1988

Lymphocytosis of large granular lymphocytes in splenectomized subjects.

Lymphocytosis of large granular lymphocytes (LGL) has been observed in 6 patients splenectomized for various pathological conditions. In all of them the LGL count was higher than 3.5 x 10(9)/l. No patient showed neutropenia nor suffered from rheumatoid arthritis. A surface markers heterogeneity was observed by immunophenotypic studies. A reversal of the CD4/CD8 ratio was observed in all patients, indicating that LGL are in the majority CD8+. Three patients showed the phenotype CD2+ CD3+ CD4- CD8+ indicating the T-lineage derivation of LGL; patient 6 showed a non-T non-B phenotype (CD2- CD3- CD4- CD8+/-). The percentage of lymphocytes presenting LGL-related markers (HNK-1, CD16, CD11b) was higher than that observed in normal subjects in 4 out of 5 examined patients. However, the percentage of cells bearing these markers was inferior to the LGL counts indicating that not all LGL express them. NK cytotoxic activity was similar to that of normal subjects in the three examined patients. Our data suggest that lymphocytosis of LGL in splenectomized subjects is a reactive process favoured by the asplenic state.

Adult↗