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Biomedical subjects

A Marchetti

Publications and source records attributed to A Marchetti.

At least 91 records · Page 5Linked to original sources
PubMed1990

Induction of the neoplastic phenotype of EBV-established B lymphocytes by the human Ha-ras oncogene.

We report on the use of human B lymphocytes immortalized by the Epstein-Barr virus (EBV) as targets for transformation by the c-Ha-ras oncogene of bladder carcinoma cells T24. Several stably transformed cell lines were obtained and their in vivo and in vitro growth properties as well as levels of expression of the ras gene were studied. The transformed phenotype in these cells was correlated to ras oncoprotein expression level; only the cell lines which overproduce p21 ras, by at least six-fold, were tumorigenic in nude mice. In this regard, our ras transformed cells behave as lymphoblastoid cells transformed by the c-myc oncogene, suggesting that c-myc and c-Ha-ras might act on the same regulatory level.

Animals↗
PubMed1989

Type 1 fiber abnormalities in skeletal muscle of patients with hypertrophic and dilated cardiomyopathy: evidence of subclinical myogenic myopathy.

Abnormalities of skeletal muscle have been described in patients with dilated and hypertrophic cardiomyopathy. Eleven patients with dilated and eight with hypertrophic cardiomyopathy without overt symptomatic skeletal myopathy underwent extensive neuromuscular studies. Quantitative electromyography showed abnormal reduction of motor unit potential duration, indicative of myogenic myopathy, in four patients (36%) with dilated and in three (37%) with hypertrophic cardiomyopathy. Values were 21% to 40% (mean 28%) lower than those in age-matched normal control subjects. The presence of normal nerve conduction velocities and of normal motor unit fiber density in all patients indicated lack of neurogenic abnormalities. Skeletal muscle biopsy was performed in five patients with dilated and in four with hypertrophic cardiomyopathy. In all nine patients light and electron microscopy showed central hyporeactive cores, selective atrophy and mitochondrial abnormalities of type 1 fibers but not of type 2 fibers. The degree of impairment of left ventricular function in patients with electromyographic abnormalities was similar to that of those without (percent fractional shortening at two-dimensional echocardiography 21 +/- 9 versus 25 +/- 10, ejection fraction at angiography 39 +/- 13% versus 42 +/- 13% and left ventricular end-diastolic pressure 21 +/- 6 versus 21 +/- 8 mm Hg) as well as symptom duration (9 +/- 4 versus 12 +/- 8 months). Thus, subclinical electromyographic alterations indicative of myogenic myopathy are frequent in patients with dilated and hypertrophic cardiomyopathy and are unrelated to the degree of impairment of left ventricular function. The concomitant histologic alterations, characterized by selective type 1 atrophy, are similar to those observed in congenital and idiopathic myopathies, but different from those described in secondary heart failure.

Adult↗
PubMed1989

Ultrastructural features of the intestinal absorption of mouse mammary tumor virus in newborn BALB/cfRIII mice.

The retrovirus mouse mammary tumor virus is present in mouse strains with a high incidence of mammary tumors as a causative agent. It is produced mainly in the mammary glands of sexually mature females and is milk-transmitted to newborns. The fate of the mouse mammary tumor virus is almost unknown. Where it enters, how it is distributed, and where it remains latent, remain unresolved problems. This study tries to answer the first of these questions. Viruses are for the most part digested in the stomach. Very few well-preserved B particles, i.e., the infective particles, are allowed to enter through a process of endocytosis, mainly in the newborn-type epithelial cells. These are epithelial cells with a very rich absorptive apparatus, characteristic of newborn rodents. The adult-type absorptive cells and the M cells of the Peyer's patches might be partly involved.

Animals↗
PubMed1989

Epstein-Barr virus-transformed human B lymphocytes endocytose autologous and heterologous red blood cells.

Epstein-Barr virus (EBV)-transformed B lymphocytes, either isolated from a patient with EBV-induced infectious mononucleosis or obtained by in vitro infection of B lymphocytes of donors in different clinical conditions, have been tested for the ability to endocytose particulate forms of antigens, such as human, sheep or mouse red blood cells. By light and electron microscopy, it has been found that EBV-transformed B cells are able to bind and internalize human autologous and allogeneic erythrocytes, as well as sheep and mouse erythrocytes, independent of the specificity of the secreted immunoglobulins. The ability of EBV-transformed B lymphocytes to endocytose and process particulate forms of autoantigens during infectious mononucleosis might have a role both in the production of heterophile antibodies and in EBV-induced autoimmunity.

Animals↗
PubMed1989

HIV infection and developmental services for adults.

The achievement of community living and greater personal independence has placed adults with developmental disabilities in a potentially vulnerable position regarding acquisition of HIV infection. Early surveys have identified a limited number of individuals who have become infected. Few states have undertaken planning for assurance of appropriate services. Program managers must consider the diverse educational and ethical issues involved; advisory committees can be of assistance. Strong antidiscrimination measures will be required for the protection of adults with developmental disabilities and HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1989

[Congenital fructose 1,6 diphosphatase deficiency. Description of a case].

In describing one case of congenital fructose 1,6-diphosphatase deficiency the Authors review the several clinical conditions giving problems of differential diagnosis. For certain diagnosis they underline the importance of liver biopsy, to dose the deficient enzyme directly in the liver tissue.

Fructose Metabolism, Inborn Errors↗
PubMed1988

Morphologic and antigenic properties of mouse mammary tumor virus produced in a hormone-responsive fashion by C57Bl/10 mammary tumors of non-viral origin.

Bl-MaTU/A1 mouse mammary tumor cells, derived from a C57B1/10 mammary adenocarcinoma induced by dimethylbenzanthracene and mammotropic hormones, express virus particles and proteins related to mouse mammary tumor virus (MMTV). Immunocytochemical analysis by means of monospecific and monoclonal anti-gp52 sera revealed a different localization of the main structural proteins of MMTV in Bl-MaTU/A1 and GR cells (the latter used as a positive virus-producing control). Immunoelectron microscopy of B-type particles budding from the microvilli of dexamethasone-stimulated Bl-MaTU/A1 cells showed remarkably weak reactivity of the viral envelope with anti-gp52-protein A-gold complexes as compared with that of dexamethasone-stimulated GR cells. Since Bl-MaTU/A1-associated MMTV originates from the amplified unit II of endogenous MMTV, which is altered probably within the env gene, the observed antigenic difference in the Bl-MaTU/A1-associated MMTV may be due to altered synthesis of gp52 glycoprotein in these cells.

Adenocarcinoma↗
PubMed1988

Biological and immunological properties of the HMB-2 human melanoma cell line.

The HMB-2 human melanoma cell line derived from a lymph node metastatis is described. After long-term cultivation in vitro the cells retained their morphology, high growth rate, xenotransplantability into immunosuppressed mice and genotypic and phenotypic markers of human melanoma cells. Upon infection of the HMB-2 cells with temperature-sensitive mutant vesicular stomatitis virus (VSVts045) at nonpermissive temperature, a complemented virus pseudotype (VSV(HMB-2] was produced carrying assembled melanoma-associated antigens. Monoclonal antibodies prepared against HMB-2 cell membrane proteins and proteins of purified VSV(HMB-2) particles showed different reactivity with various human tumor cell lines and tissues: While the RG-12 anti-HMB-2 monoclonal antibody recognized a class II tumor-associated antigen present in melanoma and carcinoma tissues, the B-6 anti-VSV(HMB-2) antibody showed selective reactivity with melanoma cells.

Animals↗
PubMed1987

Silver enhancement of protein A-gold probes on resin-embedded ultrathin sections. An electron microscopic localization of mouse mammary tumor virus (MMTV) antigens.

A simple method is described allowing the enhancement of the visibility of small gold probes for the electron microscopy. This method, which allows the silver intensification of gold directly on epon-embedded ultrathin sections, was used for the electron microscopic localization of Mouse Mammary Tumor Virus (MMTV) antigens in cultured cells derived from GR and BALB/cfRIII mouse mammary tumors. After the immunostaining with the preembedding protein A-gold technique, the ultrathin sections, placed on 200 mesh copper grids, were rehydrated and exposed to a photographic developer containing silver nitrate. During this physical development gold particles are incapsulated in growing shells of metallic silver, which gradually become more and more visible. We were able to obtain a heavy labelling of the viral particles, well visible even at low magnification, with a negligeable background staining. The present technique can be useful whenever it is necessary to use the smallest gold probes today available.

Animals↗
PubMed1986

Toxic myopathy induced by industrial minerals oils: clinical and histopathological features.

We report a case of subacute myopathy in a 47 years old man engaged on boiler maintenance at an oil-fired thermoelectric power station. The occupational history highlighted heavy exposure to inhalation of ash derived from mineral oil combustion and containing several elements, metals and metalloids, including vanadium and nickel. The presenting symptoms, clinical course and muscle histopathology suggest that exposure to toxic agents probably played an important part in the causation of the myopathy.

Humans↗