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Biomedical subjects

G Elia

Publications and source records attributed to G Elia.

At least 109 records · Page 6Linked to original sources
PubMed1988

Acute effect of indapamide on urine calcium excretion in nephrolithiasis and human essential hypertension.

The effects of indapamide (2.5 mg once a day) on urinary composition are reported in 20 patients (10 with recurrent calcium nephrolithiasis and 10 with essential hypertension) compared with 20 controls. Indapamide was well absorbed in every patient (mean plasma level at the steady state was 111 +/- 41 ng/ml) and its antihypertensive action was more pronounced in hypertensive than in normotensive patients. It lowered calcium excretion in 18/20 patients (mean fall on the 7th day of treatment: 53%) and raised the Mg/Ca ratio in 20/20 patients (mean increase on the 7th day: 167%). The effect on Ca2+ and Mg2+ excretion was not associated with a strong diuretic effect. During intravenous calcium loading (0.375 mmol/kg body weight) 6 normal subjects after a single oral dose of indapamide excreted less calcium, suggesting a direct renal hypocalciuric action by the drug. Indapamide could represent an alternative drug to thiazide diuretics in diseases with dangerous renal calcium losses, but long-term studies are needed.

Adult↗
PubMed1987

Reduced maturation of Friend virus in adhesive mutants of Friend leukemia cells.

The replication of Friend Leukemia virus (FLV) has been investigated in adhesive clones (FF) of Friend Leukemia cells which were selected via cultivation on top of human fibroblast monolayers. In these adhesive clones a shut-down of FLV production is observed under conditions of culture confluency; this finding is not due either to a reduced number of cell divisions nor to a defective expression of FLV genome as assessed by Northern blot and immunofluorescence studies. Ultrastructural studies showed that virus budding and release into the medium is not detectable under these conditions. Conversely, in confluent FF cell monolayers abundant imperfect type-A enveloped particles were visible, possibly originating from stacks of granular endoplasmic reticulum with thickened membranes. It is postulated that the reduced virus production in adhesive FF monolayers is due to as yet undetermined events taking place during virus maturation at a time coincident with that of cell-cell adhesion under conditions of culture confluency.

Animals↗
PubMed1986

Sendai virus replication in Friend erythroleukemia cells. I. Acutely and persistently infected cells become resistant to virus-induced lysis.

Friend leukemia cells (FLC) are susceptible to infection by Sendai virus, a member of the paramyxovirus group. FLC constitute a most suitable model to study virus-host cell interactions, because they grow in suspension (thus avoiding the use of trypsin), and provide an easy way of deriving single-cell clones. When FLC are infected with Sendai virus at high m.o.i., a direct, extensive lysis of the cells ensues, whereas lower doses of virus result in a cytocidal infection whose lethality depends mainly on the virus used, standard or defective interfering egg-grown Sendai virus (EGSV), and on the multiplicity of infection (m.o.i). At later times after infection, FLC become resistant to the Sendai induced lysis (SIL). The SIL resistance can be maintained in single-cell clones that had survived the first infection. The maintenance of the resistant phenotype of the clones requires the serial subcultivation of the cells in the presence of activated EGSV. The mechanisms that presumably regulate the appearance of SIL resistance in Sendai infected FLC are discussed.

Cell Fusion↗
PubMed1985

Induction and maintenance of flattened morphology in highly adhesive Friend leukemia clones depends on the time- and space-specific assembly of microtubular networks.

Indirect immunofluorescent staining with anti-tubulin antibodies, SEM and TEM were applied to study microtubule (MT) assembly in clones isolated from Friend leukemia cells (FLC, 745 A strain) on the basis of their sensitivity to exogenous fibronectin (FN). Kinetics of cell spreading and elongation were studied using computerized image analysis and SEM. In contrast to 745 A cells, FN-sensitive clones (referred to as FF clones) showed elaborate MT networks when observed by immunofluorescent staining as well as by TEM. A good correlation was found between the degree of spreading and elongation of FF cells and the degree and cellular distribution of their MT. The highest concentration of MT networks oriented parallel to the main cellular axis was observed in very elongated FF cells. The majority of MT in interphase FF cells radiated from the centrosomes; some MT apparently originated from the nuclear membranes. TEM showed the existence of morphological differences between centrosomes of 745 A and FF cells. The characteristic ultrastructure of the centrosomes of FF cells was maintained in trypsinized cells, even if such FF cells lost MT's and acquired a spherical morphology. FF cells, treated with a wide spectrum of MT-disrupting agents, promptly acquired a rounded morphology with rapid dissolution of polymerized tubulin. Removal of MT-disrupting agents from the culture medium rapidly restored a flattened morphology with concurrent regeneration of MT's. During recovery from MT-disrupting agents, FF cells showed increased numbers of centrosomes per cell. We conclude that MT networks cooperate in the attachment, spreading and elongation of FF cells isolated from FLC. Moreover, we hypothesize the existence in FF cells of a variant form of centrosomes as compared with those of 745 A cells.

Animals↗
PubMed1985

[Ionizing radiation and video computer terminals].

VDTs are more frequently being used and, therefore have given rise to the problem of security among operators exposed to possible X-ray emissions. The authors report the results of a dosimetric investigation, carried out through TLD CaF2:Dy on X-ray exposure levels close to video display terminals of a data processing center. After testing the exposure percentage values and the measurements adjusted to one-year basis, the authors report that the value are generally similar to those existing in the environment even though significant values have been found in a few cases.

Data Display↗
PubMed1984

SV40 immortalization of adult human mesenchymal cells from neuroretina. Biological, functional and molecular characterization.

Human adult mesenchymal cells from neuroretina (human choroid cells, HC) have acquired an infinite lifespan, following phenotypic transformation with a wild-type SV40. Immortalized cells (HC/SV40) contain high numbers of free circular viral DNA, and integrated molecules in a head-to-tail array in the cellular DNA. HC/SV40 cells express both the virus-coded "T" antigens and the cell-coded p53 transformation-associated protein. The transformed phenotype was further characterized by loss of contact inhibition of cell division, inability to induce the retraction of a fibrin clot and to spread within fibrin, and the existence of an altered distribution of actin cables. For the first time we also describe a coupling of the immunofluorescence and the quantitative cytofluorometric analyses, a new transformation parameter, since we show that SV40 transformation causes reorganization of the cell membrane by inducing the unmasking of the antigen recognized by the 4F2 monoclonal antibody, which is present in a "cryptic" form in the untransformed cells. Though the HC/SV40 cells have been continuously passaged over a 3-year period, they have not yet achieved a fully malignant phenotype, since they retain serum-dependency and the presence of a well developed fibronectin pericellular network, and they are not tumorigenic in nude mice. Thus this human immortal cell line constitutes a very useful tool for studying the progression toward full malignancy and the relationships between evolution of transformation parameters and changes in the viral and cellular genome interplay.

Adult↗
PubMed1984

Skeletal muscle cell abnormalities in acute hypophosphatemia during total parenteral nutrition.

Muscle tissue H2O, Na, K, Mg, Cl and total P were studied in 23 patients with acute hypophosphatemia during P-deficient total parenteral nutrition. Increased muscle extracellular water and low intracellular K and Mg with high intracellular Na were found. These abnormalities were detected either in previously underfed patients with low muscle P or in well-nourished, acutely ill subjects with muscle P near to normal. These findings show that acute depletion of extracellular inorganic P is associated with changes of muscle cell composition independently of muscle cell P content.

Acute Disease↗
PubMed1982

Acquisition of sensitivity to exogenous fibronectin by Friend leukemia cells correlates with reduction of their tumorigenic potential.

Strongly adhesive, highly flattened clones (FF clones) can be selected from Friend leukemia cells (FLC) cultivated on top of monolayers of human embryonic fibroblasts (HEF). The flattened phenotype of FF clones is stable during cell replication either in soft agar or in vivo. With the number of passages of FLC on HEF the fibronectin (FN) sensitivity of FF clones increases with a proportional reduction of their tumorigenicity. The FN-sensitivity was defined as the ability of a certain dose of FN to flatten 50% of cells of a given FF clone. Tumorigenicity was defined as the number of FF cells able to give palpable tumors, in 50% of inoculated mice. Exogenous FN does not modify the duplication time of FF clones but strongly influences their growth behavior. In the presence of FN, the growth rate of FF cells is controlled by the size of the growth are available. Highly FN-sensitive FF cells grown on FN-coated substrata die at confluency while FF cells not adherent to substrata escape cell death and grow in suspension. We conclude that the high intrinsic FN-sensitivity of FF cells and FN availability at the site of tumor inoculation could be responsible for the reduced tumorigenicity of highly flattened FF clones.

Animals↗
PubMed1981

Electron spin resonance of growing normal and virus-transformed cells.

A g = 2.003 ESR signal, attributed to a free radical localized in HeLa cell nuclei and mitochondria but absent in membranes and cytoplasm, has been studied as a function of the culture growth cycle in normal (NRK and 3T3) and virus transformed (NRK/RSV and 3T3/SV40) cells. For both these cell pairs, the signal is higher during the "lag" stage and lower during the "growth" stage. The average specific intensity of the signal in normal cells is about twice that in virus-transformed cells. However, the maximal point of resonance during the lag state is higher in transformed cells than in normal ones. The lag stage in NRK and NRK/RSV cells is much longer than in 3T3 and 3T3/SV40 cells, while the maximal value of the g = 2.003 ESR signal occurs, early in the lag stage of 3T3 and 3T3/SV40 cells and late in the lag stage of NRK and NRK/RSV cells.

Animals↗
PubMedDate not supplied

Wheat germ agglutinin-binding protein changes in highly malignant Friend leukemia cells metastasizing to the liver.

We have used binding of radioactive lectins (i.e. Concanavalin A (ConA), Wheat Germ Agglutinin (WGA) and Ricinus communis agglutinin I (RCAI)) to membrane glycoproteins separated in SDS gel electrophoresis, to detect specific carbohydrate changes in plasma membrane proteins of in vivo passaged Friend erythroleukemia cells (FLC). These cells are highly metastatic to the liver, whereas the original in vitro passaged tumor cells do not metastasize. Marked qualitative differences in the high molecular weight region of the gels (100-200 kD) were observed between the WGA binding glycoproteins of metastatic in vivo passaged FLC and nonmetastatic in vitro passaged FLC. Furthermore, the binding of WGA to plasma membrane proteins of in vivo passaged FLC was much greater than the binding of WGA to plasma membrane proteins of in vitro passaged FLC. Lectin binding experiments after sialic acid removal by in situ mild acid hydrolysis of FLC glycoproteins indicated that an increased sialylation of the 120 and 145 kD glycoproteins was responsible for the increased WGA reactivity of in vivo passaged FLC plasma membranes. Besides the increased sialylation, other changes in glycosylation of the 100-200 kD glycoproteins of in vivo passaged FLC were observed: (1) qualitative differences between the WGA binding patterns of the two cell types were restored after treatment of the gels with mild acid and subsequent Smith degradation; (2) after chemical removal of sialic acid residues from the gels, qualitative differences in the RCA binding patterns to the glycoproteins of the two cell types were apparent.

Animals↗
PubMedDate not supplied

New approaches for the molecular characterization of canine parvovirus type 2 strains.

Characterization of the canine parvovirus type 2 (CPV-2) is sometimes ambiguous, frequently requiring more than one technique for definitive prediction of the viral type. Taking into account the single-nucleotide polymorphisms encountered in the VP2-protein gene between types 2a and 2b and between type 2b and Glu-426 mutant (type 2c), two different minor groove binder (MGB) probe assays were developed for rapid identification of the CPV-2 variants. A total of 315 samples collected from dogs with diarrhoea were screened for CPV-2 by a real-time polymerase chain reaction (PCR) assay capable of detecting all CPV-2 types. In order to compare the type-specific assays with the traditional techniques [haemagglutination inhibition with monoclonal antibodies, PCR-restriction fragment-length polymorphism (RFLP), sequence analysis] for prediction of CPV-2 antigen specificity, the 203 samples tested CPV-2 positive were analysed using the different methods. The results showed a 100% concordance between the MGB probe assays and the combined conventional methods, with 116 samples characterized as type 2a, 32 as type 2b and 55 as type 2c. Therefore, the MGB probe assays represent a quick, reliable tool for prediction of CPV-2 antigen specificity, with regard to the more time-consuming assays currently used.

Animals↗
PubMedDate not supplied

Antibody levels and protection to canine parvovirus type 2.

The relationship between maternally derived antibody (MDA) levels and protection to canine parvovirus (CPV) infection in pups is reported. Twelve pups with a wide range of haemagglutination inhibiting (HI) titres of MDA to CPV were divided into four groups, with each group balanced for antibody titres. The dogs were inoculated with a field CPV-2b strain and clinical signs, virus shedding and antibody response were assessed. The CPV was not detected in the faeces of dogs with HI titres of 320 at any time. In dogs with HI titres up to 160, active CPV replication after challenge was demonstrated by real-time polymerase chain reaction. The successful infection of dogs with HI titres of 80 and 160 was confirmed by seroconversion, evaluated at day 14 post-infection. These findings demonstrated that CPV infection could also occur in the presence of MDA HI titres (> or =80) usually considered fully protective.

Animals↗
PubMedDate not supplied

Surveillance activity for canine parvovirus in Italy.

Recent identification of unusual canine parvovirus (CPV) mutants in cats and dogs suggests that CPV type 2 (CPV-2), which emerged suddenly in the late 1970s, is undergoing continual genetic and antigenic variations. A peculiarity of parvoviruses is that single-nucleotide substitutions may determine drastic phenotypic changes. The effects of either natural or artificial mutations on CPV phenotypic properties have been largely investigated, and this sets up CPV as an interesting model to study virus evolution. By monitoring the evolution of CPV-2 in Italy, we observed the onset and quick spread of a Glu-426 mutant, antigenically different from the pre-existing variants that were partially displaced within a few years of the initial identification of the new mutant. The identification of CPV-2 variants raises several questions concerning their impact on the efficacy of the current CPV-2 vaccines, based on the original CPV-2 strain that no longer exists in the field.

Animals↗