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Biomedical subjects

D Zaccheo

Publications and source records attributed to D Zaccheo.

At least 73 records · Page 4Linked to original sources
PubMed1989

[A new type of small calibre carbon fiber arterial prosthesis].

A new type of vascular prosthesis, made of pyrolytic carbon fibres, was tested on growing pigs. Fourteen grafts (4 x 33 mm) were implanted on the infrarenal aorta and removed 15 s, 60 m and 7, 15, 30, 60 and 120 days after surgery. Specimens were examined by light and scanning electron microscopy. As controls ten pigs underwent excision and re-implantation of a 30 mm segment of infrarenal aorta. Autografts were removed 7 to 120 days after surgery. All but one carbon grafts, as well as all autografts were patent at the time of removal. Basic characteristics of carbon grafts, as shown by the present study, may be summarized as follows: 1) thromboresistance of the inner surface, at the time of implantation, 2) development of a thin neo-intima, 3) rapid and complete endothelialization of the flow surface, 4) good viability of the inner layers and 5) solid anchorage to peri-graft tissues.

Animals↗
PubMed1989

[Carbon fiber composite biomaterials in the substitution of the inferior vena cava].

A new type of vascular prosthesis made of pyrolytic carbon fibres, was tested on growing pigs. Fourteen graft (8 x 30 mm) were implanted as inferior vena cava (IVC) substitutes. The blood conduits were removed 15 s, 60 min and 7, 15, 30, 60 and 120 days after implantation. Specimens were examined by light and scanning electron microscopy. Ten similar pigs underwent excision and re-implantation of 30 mm segment of IVC, and where used as controls. Carbon fibres grafts removed within 7 days after implantation were patent: at the subsequent observation times, the prosthetic segments appeared completely or partially thrombosed. Four of the 10 venous autografts failed. Shortly after implantation, a thick neointimal layer covered the inner surface of carbon grafts. This phenomenon delayed organization and neo-endothelialization of the neointima, exposing carbon segments to blood deposits.

Animals↗
PubMed1989

[Hereditary sensory motor neuropathy: degenerative disease or a disease with an immune-mediated pathogenesis?].

The clinical data proving that some hereditary motor-sensory neuropathies (HMSN type 1) are steroid sensitive may indicate inflammatory or immunomediated mechanisms as cofactors contributing to the clinical course of these disorders. The finding of HLA-DR positivity of Schwann cells in HMSN type I along with the presence in some cases of inflammatory infiltrates in nerve sections provides further evidence for this hypothesis.

Autoimmune Diseases↗
PubMed1988

HLA-DR Schwann cell reactivity in peripheral neuropathies of different origins.

HLA-DR antigens have been found on Schwann cells in peripheral neuropathies of different origins but not in normal control cases. Class II antigen reactivity was more intense in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and hereditary motor and sensory neuropathy type 1 (HMSN), but was also observed in toxic or metabolic neuropathies. The expression of HLA-DR antigen on Schwann cells does not appear to be related to the inflammatory or autoimmune origin of the disease.

Antibodies, Monoclonal↗
PubMed1986

Use of the polytetrafluoroethylene surgical membrane for control of intra-abdominal adhesions.

The new polytetrafluoroethylene (PTFE) surgical membrane is specifically designed to prevent adhesion formation. The present study was planned in order to evaluate the effectiveness of the PTFE surgical membrane as a parietal peritoneal substitute. Furthermore, the effects of the suture material used to implant the membrane under different operating conditions (clean or contaminated surgery) were also evaluated. One hundred-eighty rats were divided into 9 groups and underwent the following surgical procedures: Group 1: removal of a parietal peritoneum patch, which was left unrepaired; Group 2: a similar peritoneal defect was covered with the PTFE membrane by 8 polypropylene sutures; Group 3 (control group): only the 8 polypropylene suture were placed on the margin of the standard peritoneal defect; Group 4: the same procedure as in Group 2, using as sewing material PTFE sutures; Group 5 (control group): only the 8 PTFE sutures were placed on the margin of the standard peritoneal defect; Group 6, 7, 8 and 9: the same procedures as in Group 2, 3, 4 and 5 respectively, adding division and subsequent reanastomosis of the caecum. Animals of each group underwent a second laparotomy 10 days or 3 months after surgery for evaluation of the extent and density of adhesions, and of the intraperitoneal organ involvement. Histological examination of adhesions which formed was then carried out. No adhesions developed in rats of group 1, while they were always present in all the other groups. Under clean surgery, the adhesions were limited to the margin of the peritoneal defect, while under contaminated surgery they formed also on its central portion. The PTFE surgical membrane itself caused variations neither of the extent and density of adhesions which developed nor of the magnitude of intraperitoneal organ involvement. The type of suture material used to implant the membrane had no effect on adhesion formation.

Abdomen↗
PubMed1985

Establishment and characterization of a new human cloned myelomonocytic cell line (ZC-1.6).

A human cell line, ZC, derived from the blood of a patient with acute myelomonocytic leukemia, was established and cloned. One of the clones, ZC-1.6, was subsequently characterized. As for its morphology and cytochemistry, ZC-1.6 clone shares a number of features with immature cells of the monocytic or myelocytic lineages. Surface marker analysis shows positivity for 4F2 (100% of the cells), and OKM1 (38%) monoclonal antibodies, and presence of surface HLA-D/DR antigens (100%) and Fc (11%) and complement (C3b) receptors (100%). Functional capabilities of ZC-1.6 cells include adherence, spreading, and phagocytosis of latex and opsonized zymosan particles. Despite its morphological immaturity, the ZC-1.6 clone produces relevant amounts of O2- in the presence of different stimuli (phorbol myristate acetate, opsonized zymosan, or latex particles). The production of O2- by ZC-1.6 cells is the first evidence that reactive oxygen intermediate production may represent an early feature of cells of the myelomonocytic lineage.

Adult↗
PubMed1984

Human placental Hofbauer cells promote mitogen induced T cell proliferation.

Hofbauer cells are a major cell type of the human placental villous core particularly numerous at the beginning of pregnancy. In the present study we have investigated whether or not Hofbauer cells could subserve the function of accessory cells for colony formation by phytohemagglutinin stimulated allogeneic T cells. Results showed that Hofbauer cells are capable to play an accessory role on T cell proliferation probably due to the release of interleukin 1-like soluble factors.

Colony-Forming Units Assay↗
PubMed1984

Progesterone enhances reactive oxygen intermediates production by cultured human monocytes.

Progesterone at placental tissue concentrations (5-20 micrograms/ml) markedly increases in vitro PMA-stimulated O-2 and H2O2 production by human cultured monocytes. This appears to contrast the well-known suppressive action of the hormone on the other cell mediated defence mechanisms. We suggest that these findings could cast a new light on progesterone's multiple and differentiated functions in the placental environment.

Cells, Cultured↗
PubMed1984

Scanning electron microscopy of stromal cells of human placental villi throughout pregnancy.

Morphological changes in fixed stromal cells and Hofbauer cells were studied throughout pregnancy in different types of placental chorionic villi by scanning electron microscopy. In the mesenchymal villus the fixed stromal cells were characterized by thin cytoplasmic processes. Hofbauer cells exhibited blebs on their surface. Large sail-like processes with a crescent profile which surrounded well developed stromal channels and a small cell body typified the small reticulum cells of the immature intermediate villus. The Hofbauer cells here displayed blebs, microplicae and large lamellipodia. Short cytoplasmic expansions and a large cell body characterized the fibroblasts present inside the stem villus. Hofbauer cells were rare, having blebs or a few short lamellipodia. The mature intermediate villus contained small and large reticulum cells. The latter had a much larger cell body than the small ones and displayed a few short cytoplasmic processes partly delimiting narrow incomplete stromal channels. Occasional Hofbauer cells with small microplicae and/or blebs were present. The small reticulum cells and fibroblasts present in the terminal villus showed similar morphological features as above. However, the former exhibited less developed cytoplasmic extensions and therefore no stromal channels were observed. In the terminal villus, the morphology of the rare Hofbauer cells was similar to that found in the mature intermediate villus.

Chorionic Villi↗
PubMed1984

The stromal architecture of the immature intermediate villus of the human placenta. Functional and clinical implications.

Scanning electron microscopy of cryofractured immature intermediate villi showed numerous intercommunicating channels in the central region of the stroma, oriented mostly parallel to the major axis of the villus. In the stromal channels, numerous Hofbauer cells were present and their aspect and position inside the channels highly suggested a motility of these cells. These morphological data strongly support the fundamental role played by the immature intermediate villus in the normal and pathological development of the human placenta.

Cell Differentiation↗
PubMed1980

A three-dimensional study of the normal human placental villous core. I. The Hofbauer cells.

In order to study the three-dimensional ultrastructure of the Hofbauer cells, human placentae from the 6th to the 21st week of gestation and also from the end of pregnancy were cryofractured and observed by scanning electron microscopy. Hofbauer cells were found in the villous core at all the gestation stages examined. Their surface morphology was characterized by lamellipodia, funnel-like structures, blebs and microplicae. This pleomorphic aspect was probably related to functional or environmental conditions. In addition, thin cytoplasmic processes connected the Hofbauer cells with each other and with the components of the villous stroma. Fractured Hofbauer cells revealed large vacuoles in the cytoplasm; the vacuoles were smaller in size both at the beginning and at the end of pregnancy. This study further attests to the macrophagic nature of these cells.

Chorionic Villi↗
PubMed1980

Lymphocyte subpopulations in cerebrospinal fluid and peripheral blood in multiple sclerosis.

Lymphocytes subpopulations in cerebro-spinal fluid (CSF) and peripheral blood (PB) from multiple sclerosis (MS) patients were studied. PB of MS patients contains the same prevalence of E and EA rosette forming cells compared with controls, consisting of patients affected by various "nonimmunological" neuropsychiatric diseases. Cytochemical identification by the method of acid esterases in PB demonstrated in MS a prevalence of lymphocyte subpopulations similar to controls, and a relatively high percentage of macrophages compared with other methods, especially in MS patients: this may partially account for variable results obtained by various authors with the rosette technique. In CSF a significant decrease of total T, and particularly of T gamma cells, was found. Since T gamma lymphocytes have a suppressor effect on B cell proliferation and Ig synthesis, their decrease could be related with Ig hypersynthesis commonly found in the central nervous system of MS patients.

Adolescent↗
PubMed1979

Alpha-naphthyl acetate esterase activity in human lymphocytes: distribution in lymphocyte subpopulations and in mitogen-activated cells.

The cytochemical demonstration of nonspecific alpha-naphthyl acetate esterase (ANAE) activity in human peripheral blood mononuclear cells was studied. Different staining patterns were found, allowing differentiation of mononuclear cells into macrophages (strong granular cytoplasmic activity), B lymphocytes (negative reaction), Tgamma lymphocytes, i.e. bearing IgG Fc receptors (granular scattered reaction), and T non-gamma lymphocytes, i.e. devoid of IgG Fc receptors (single cytoplasmic ANAE spot). During the early phases of phytohaemagglutinin (PHA)- and concanavalin A (Con A)-induced activation, the reactivity of most lymphocytes became granular and scattered, similar to that found in Tgamma cells. Blast cells generating in successive phases appeared devoid of detectable enzymatic activity. The hypothesis is put forth that T cells showing granular, scattered reactivity represent a population of activated cells and that the redistribution of enzymatic activity could represent a preliminary step leading to secretion (lymphokine-like?) of enzyme from cytoplasm in the course of cell activation.

B-Lymphocytes↗
PubMed1978

Surface markers on lymphocytes from human cerebrospinal fluid. Predominance of T lymphocytes bearing receptors for the Fc segment of IgG.

Surface markers of cerebrospinal fluid (CSF) cells have been studied in comparison with those of peripheral blood lymphocytes. The great majority (about 95%) of CSF cells bear surface markers of thymus-dependent lymphocytes (E rosettes with uncoated sheep red blood cells), while being devoid of bone-marrow derived cell markers (EAC rosettes with complement-coated red blood cells). In contrast with lymphocytes from peripheral blood, CSF cells form predominantly 'early' and 'sphere'-shaped E rosettes, and bear receptors for the complement-fixing segment of immunoglobulins G. Treatment with concentrated CSF does not affect rosette forming ability of peripheral blood lymphocytes.

Cerebrospinal Fluid↗
PubMed1978

Subpopulations of T lymphocytes in human extravascular fluids.

Surface markers of lymphocytes from various human extravascular fluids (cerebrospinal fluid, aqueous humour, colostrum, breast and ovary cyst fluids, peritoneal and pleural transudates) are compared with those of lymphocytes from peripheral blood. Significantly higher percentages of T cells are found in all extravascular fluids: the great majority of extravascular T lymphocytes show high E rosette-forming ability and bear IgG Fc receptors (T Fc+ cells). Functional implications of the shown high predominance of T Fc+ cells in extravascular fluids are discussed on the basis of presently available information on the immunological role of such cells (cytotoxic? suppressor? amplifier?).

Antigens↗