Search PubMed⌕ Search

Biomedical subjects

G Pepe

Publications and source records attributed to G Pepe.

180 records · Page 10Linked to original sources
PubMedDate not supplied

Uptake of fluorochrome-labelled exotoxins by different cell types in culture.

The uptake of diphtheria toxin and of Staphylococcus alpha-toxin by two different human cell types cultured in vitro (the HEp-2 continuous cell line and human adult hepatocytes) was studied by fluorescence microscopy and phase-contrast microscopy. The behavior of these two bacterial exotoxins was quite different. Diphtheria toxin was incorporated into cells by pinocytosis, whereas alpha-hemolysin penetrated into the cytoplasm probably through lesions in the cell membrane. In addition, the penetration of diphtheria toxin into the cells was not inhibited by specific antiserum, whereas anti-alpha-haemolysin inhibited the penetration of alpha-tpxin through the cell membrane. The significance of these findings is discussed.

Animals↗
PubMedDate not supplied

Ultrastructural changes in HEp-2 cells treated with staphylococcal alpha-toxin.

The effect of highly purified staphylococcal alpha-toxin on HEp-2 neoplastic cells growing in culture was studied by electron microscopy. In addition to some nuclear modifications, the most significant morphological changes were in mitochondrial structure, alpha-toxin seems to induce a defined sequence of changes in mitochondrial configuration which can be summarized as an earlier phase of 'condensation' of mitochondrial structure and a later phase of mitochondrial swelling with an intermediate 'transitional' configuration. The significance of these findings is discussed in the light of the present state of knowledge of the biological characteristics of staphylococcal alpha-toxin.

Bacterial Toxins↗
PubMedDate not supplied

The mismatch choice in liver transplantation: a suggestion for the selection of the recipient in relation to the characteristics of the donor.

Two hundred seventy-six liver transplants were retrospectively reviewed to analyze 6-month graft survival in relation to the combination of donor quality (standard donor vs nonstandard donor) and risk related to the severity of recipient liver disease low-risk, ie, United Network for Organ Sharing [UNOS] status 3/2b; high-risk, ie, UNOS status 1/2a). The overall 6-month survival rate of 82% was stratified into 4 classes: (1) standard donor to low-risk recipient = 88%; (2) standard donor to high-risk recipient = 86%; (3) nonstandard donor to low-risk recipient = 84%; and (4) nonstandard donor to high-risk recipient = 67%. According to the observed graft survival in the 4 different classes, 2 simulations were performed: the "match simulation" (transplantation of all low-risk recipients using standard donors, and transplantation of all high-risk recipients using nonstandard donors), and the "mismatch simulation" (transplantation of all the high-risk patients using low-risk donors and transplantation of low-risk patients using high-risk donors). The 6-month survival rates, calculated using the match simulation, were 74% and using the mismatch simulation, 84%. The authors suggest that, in the era of marginal donors, the recipient should be selected in relation to the characteristics of the donor according to the mismatch model.

Computer Simulation↗
PubMedDate not supplied

Synthesis and anti-HIV activity of alpha-thiophenoxy-hydroxyethylamide derivatives.

A series of new anti-HIV derivatives containing a novel alpha-thiophenoxyhydroxyethylamide core have been synthesized, using S-phenylbenzenethiosulfonate as the thiosulfenylating reagent. Some of the new synthesized compounds (1a, 1c, 1g, 1i, 1j and 1l) inhibited HIV replication in cell culture assays (syncytia formation) with effective concentrations (EC(50)) ranging from 0.1-1 microM. Incorporation of thiophenoxy substitution within various pseudomimetic peptide backbones provided a series of highly potent HIV inhibitors.

Alkanes↗
PubMedDate not supplied

Internal deletion in a collagen gene in a perinatal lethal form of osteogenesis imperfecta.

Cloned probes specific for unique genes have proven to be powerful tools in defining the nature of genetic diseases such as the thalassaemias and growth hormone deficiencies. A similar approach should be useful in defining heritable diseases of type I collagen, the heterotrimer of two alpha 1(I) chains and one alpha 2(I) chain, which is the most abundant member of the collagen family of proteins. Recently, cloned cDNAs and genomic DNAs for the two polypeptide chains of the type I collagen have become available and have been used to elucidate the chromosomal location of the corresponding genes. Here, we have used several of these cloned DNAs to demonstrate the presence of an internal deletion of about 0.5 kilobases (kb) in one allele for the pro alpha 1(I) chain in a patient with osteogenesis imperfecta (OI), a group of heritable disorders which are characterized by brittle bones but which are highly heterogeneous both phenotypically and biochemically.

Animals↗
PubMedDate not supplied

Analysis of three RFLPs of the COL1A2 (Type I Collagen) in the Amhara and the Oromo of Ethiopia.

BACKGROUND: The present composition of the Ethiopian population is the result of a complex and extensive intermixing of different peoples of North African, Near and Middle Eastern, and south-Saharan origin. The two main groups inhabiting the country are the Amhara, descended from Arabian conquerors, and the Oromo, the most important group among the Cushitic people. With the exception of some surveys on the general Ethiopian populations, little is known about the degree of genetic differentiation between the Amhara and the Oromo. AIM: The study seeks to investigate the genetic structure of these two heterogeneous Ethiopian populations and to characterize their relationships with other African and Mediterranean peoples. SUBJECTS AND METHODS: Amhara and Oromo individuals (n = 171) were analysed for three RFLPs (restriction fragment length polymorphisms) of the COL1A2 gene. To better define the genetic relationship between the two Ethiopian groups, and also between African and non-African peoples, genetic distances among Amhara, Oromo and other populations were estimated using the COL1A2 allele and haplotype frequencies, and the allele frequencies of 16 additional classical markers. RESULTS: chi(2) analysis applied to the COL1A2 allele and haplotype frequencies showed a small but statistically significant degree of heterogeneity between the two Ethiopian populations. Combining the information obtained from the three RFLP markers, a significant level of differentiation (Fst = 0.0147, p = 0.036) was also detected between Amhara and Oromo. The genetic distance analysis showed the separation between African and non-African populations, with the Amhara and Oromo located in an intermediate position. This pattern is consistent with the location of the two Ethiopian groups in other genetic analysis and with cultural data. CONCLUSIONS: The present findings suggest the presence of a differential level of genetic relatedness with south-Saharan peoples in the two Ethiopian groups, which could reflect their different history and seems to indicate the existence of genetic sub-structure within the country.

Alleles↗
PubMedDate not supplied

COL1A2 (type I collagen) polymorphisms in the Colorado Indians of Ecuador.

BACKGROUND: EcoRI, MspI and RsaI restriction fragment length polymorphisms (RFLPs) of the COL1A2 (type I collagen) gene are proving to be extremely informative markers for describing human populations; therefore they hold considerable potential for anthropogenetic research. AIM: The objective of this study was to characterize at the DNA level the Colorado Indians from Ecuador, for whom only blood group frequency information is available, and to investigate their relationships with the Cayapa-another Ecuadoran Native American group belonging to the same linguistic affiliation-and other world populations. SUBJECTS AND METHODS: Colorado Indians (n = 80) were analysed for the three anthropologically informative RFLPs of the COL1A2 gene. To better define the genetic relationship between this group and other populations, principal component analysis (PCA) was performed and genetic distances were estimated. Population genetic structure was tested through analysis of molecular variance (AMOVA) by comparing haplotype frequencies. RESULTS: COL1A2 allele and haplotype frequencies showed a certain degree of heterogeneity between the two Chibchan populations of Ecuador. The AMOVA test detected a significant level of differentiation (Fst = 0.034, p = 0.0049) between Colorado and Cayapa Indians. PC and genetic distance analyses showed a clear-cut separation between African and non-African populations; within the latter, the two Native American groups were differentiated from each other. CONCLUSIONS: The present findings suggest the presence of a low level of genetic relatedness between the Colorado and the Cayapa, despite their supposed common ethnogenesis. This confirms what has been inferred from other genetic data about the high degree of heterogeneity among Native Americans, even within the same linguistic branch, thus supporting the existence of genetic sub-structure within the central and southern American populations.

Alleles↗
PubMedDate not supplied

Activated protein C resistance is a risk factor for central retinal vein occlusion.

Central retinal vein occlusion is one of the most common retinal vascular disorders. Few and contrasting data are available on the prevalence of hemostatic risk factors in patients with central retinal vein occlusion. The aim of this study was to investigate the most common hemostasis-related inherited risk factors for venous thrombosis in a group of 53 central retinal vein occlusion patients (median age 59 years, range 18-77 years) and in 53 comparable control subjects (median age 57 years, range 22-84 years). No difference was found in antithrombin III, protein C and protein S plasma levels between patients and controls. At univariate analysis, activated protein C resistance (odds ratio 5.8) and factor V Leiden (odds ratio 4.4) were significantly associated with central retinal vein occlusion whereas G20210A polymorphism of the prothrombin gene was not. After adjustment for sex, age, and the other classic vascular risk factors (hypertension, diabetes, hypercholesterolemia, smoking) activated protein C resistance remained the only independent risk factor for central retinal vein occlusion (odds ratio 11.5). These data indicate that activated protein C resistance may play a role in the pathophysiology of central retinal vein occlusion.

Activated Protein C Resistance↗
PubMedDate not supplied

[D-dimer in the year 2000: current data and new perspectives].

D-dimer is a product of cross-linked fibrin degradation by the fibrinolytic system. It has been shown to be highly sensitive and moderately specific for venous thromboembolic disease. Thus, the most common clinical use of D-dimer relates to its negative predictive value for deep vein thrombosis and pulmonary embolism. Diagnosis, however, should not be based solely on this parameter, and an integrated strategy that combines clinical approach (pre-test probability), a non-invasive test (ultrasonography or lung scan) and D-dimer assay is highly recommended. Over the last years a number of studies have demonstrated that D-dimer may also enable the prediction of the complications of atherothrombosis inasmuch as the data available suggest a significant association of D-dimer with the risk of coronary artery disease independent of classic risk factors. Moreover, elevated plasma D-dimer seems to be a marker of a systemic prothrombotic state, and anticoagulation can normalize its levels. However, further studies are needed to assess whether or not this parameters is of clinical value to predict or prevent arterial thrombotic events in the single patient.

Algorithms↗
PubMedDate not supplied

Hyperhomocysteinemia in renal transplant patients: an independent factor of cardiovascular disease.

Hyperhomocysteinemia (Hcy) is an independent factor of cardiovascular disease, which is the main cause of morbidity and mortality both in uremic and kidney transplant patients. The aim of the study was to determine Hcy, plasminogen activator inhibitor (PAI-1) and lipoprotein (a) (Lp(a)) serum levels in 70 patients with a well functioning renal transplant. We also verified whether these levels were modified by a multivitamin therapy. The genetic polymorphism of the methylenetetrahydrofolate reductase (MTHFR) enzyme which plays a main role in Hcy metabolism, was studied as well. We found Hcy, PAI-1 and Lp(a) levels significantly elevated with respect to healthy control subjects. The thermolabile form of the MTHFR enzyme was linked to higher Hcy levels. After a short time on therapy with B6, B12 and folic acid vitamins, Hcy and PAI-1 decreased to normal levels. The authors conclude that high Hcy levels could be a relevant covariate for cardiovascular disease in transplant patients and they suggest that vitamin supplementation be recommended as a part of therapy.

Cardiovascular Diseases↗
PubMedDate not supplied

[Cancer and pregnancy. Retrospective study on the frequency in 57,393 deliveries].

Between 1950 and 1984 out of 57.393 women who delivered at the First Department of Obstetrics and Gynecology, Catania University Medical School, Catania, Italy, 40 cases of malignant neoplasia were diagnosed with an incidence of one case in 1.434 deliveries. The most frequent neoplasias is cervix carcinoma (21 cases; 52.5%), followed by breast cancer (6 cases; 15%), ovarian cancer (4 cases; 10%) and leukemia (4 cases; 10%). There was very rare association with Hodgkin disease (2 cases; 5%), osteosarcoma (1 case; 2.5%), medulloblastoma (1 case; 2.5%), and skin melanoma (1 case; 2.5%). Since cancer of the uterine cervix is the most frequent neoplasia (one cases out of 2.733 deliveries), cervical smear should be performed during pregnancy in women that never performed it.

Female↗
PubMedDate not supplied

Phagocytosis and cellular metabolism (a study on mouse and human macrophages in culture).

The uptake of foreign particles by mouse and human macrophages influenced by various metabolic inhibitors was examined in order to obtain further informations about the energy-dependent mechanisms which are involved in the phagocytic process. The inhibitors employed were iodoacetate, fluoroacetate, fluoride, malonate, sodium azide, 2-4-dinitrophenol, cycloheximide and ouabain. These substances were tested on monolayer cultures and the phagocytosis assay was performed by using zymosan suspension in the nutrient media. The quantitation of phagocytosis was obtained by the direct count of intracellular zymosan particles (immersion microscopy, 100x) and the results were evaluated and compared by biometrical analysis. The effects of these inhibitors on phagocytosis and their relation with the metabolic intracellular pathways are discussed.

Animals↗