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Biomedical subjects

G Grimaldi

Publications and source records attributed to G Grimaldi.

At least 73 records · Page 4Linked to original sources
PubMed1986

Increase in urokinase plasminogen activator mRNA synthesis in human carcinoma cells is a primary effect of the potent tumor promoter, phorbol myristate acetate.

The effect of tumor promoters and growth factors on the synthesis of urokinase and urokinase mRNA in human carcinoma cells has been investigated. In urokinase-producing human carcinoma cells (A1251), a 20-40-fold increase in urokinase mRNA level is obtained after treatment with 10 nM phorbol myristate acetate (PMA), a smaller effect (two- to fourfold) with 2 ng/ml platelet-derived growth factor (PDGF) and no effect with epidermal growth factor (EGF) (up to 50 nM). After treatment with PMA, urokinase mRNA level increases already at 30 min peaking 2-4 h thereafter. Cell line A431, which has an abnormally high number of EGF receptors, shows the same response to PMA, but also responds to EGF (two- to fourfold increase in mRNA). The kinetics are similar to those of A1251. Nuclear transcription experiments show that the PMA-induced increase in urokinase mRNA is due to increased synthesis. The protein synthesis inhibitor, cycloheximide (10 micrograms/ml), also increases the level of urokinase mRNA. When both cycloheximide and PMA are used, super-induction is observed. This result may indicate that a short-lived protein negatively regulates the level of urokinase. The different efficiency of the effectors (PMA and PDGF better than EGF) and their kinetics, as well as the effect of cycloheximide on urokinase mRNA synthesis, (a) are reminiscent of the effect of PDGF and PMA on competence phase genes (Kelly, K., B.H. Cochran, C.D. Stiles, and P. Leder, 1983, Cell, 35: 603-610), (b) demonstrate that the synthesis of urokinase is part of the early cellular response to these factors, and (c) provide a preliminary insight in the overproduction of urokinase by primary malignant tumors and transformed cells in culture.

Carcinoma, Squamous Cell↗
PubMed1986

A further study on the prevalence of multiple sclerosis in Sicily: Caltanissetta city.

The prevalence of probable multiple sclerosis (MS) in Caltanissetta city, Sicily, is at least 51 per 100,000. If possible multiple sclerosis patients are included, it is 54 per 100,000. This value is similar to that found in other cities in Sicily: Enna, Monreale and Agrigento. The high prevalence of multiple sclerosis in Caltanissetta confirms the previous data on Sicily and emphasises the importance of small population studies in the epidemiology of MS.

Adolescent↗
PubMed1986

Isolation of Leishmania mexicana amazonensis from the bone marrow in a case of American visceral leishmaniasis.

The first documented human case of visceral leishmaniasis caused by L. mexicana amazonensis is reported. Leishmania were isolated from bone marrow aspirate material from a typical visceral leishmaniasis patient. Further characterization by isoenzyme electrophoresis and by a panel of species- and subspecies-specific monoclonal antibodies established its classification as L. m. amazonensis.

Antibodies, Monoclonal↗
PubMed1985

The human urokinase-plasminogen activator gene and its promoter.

The urokinase type of plasminogen activator (uPA) is subject to regulation by hormones, phorbol esters and oncogenic transformation. This enzyme has been suggested to play a key role in processes involving cell migration and tissue remodeling, and to be essential for tumor metastasis. In order to study these processes, we have isolated the human uPA gene, and have determined its entire nucleotide sequence. The gene is organized in 11 exons and is 6.4 kb long. The 5' end of uPA mRNA has been determined by both S1 mapping and primer extension experiments. A fragment of 800 bp containing the entire 5' flanking region shows promoter activity when introduced upstream of a bacterial chloramphenicol acetyltransferase gene and introduced into human cells. The hexanucleotide sequence GGCGGG, previously found at similar regions in several viral and eukaryotic promoters and shown to be essential for promoter activity (McKnight et al. (1984) Cell, 37, 253-262), is repeated three times between the CAAT and the TATA boxes.

Base Sequence↗
PubMed1985

Establishment of a continuous cell line from fibrotic schistosomal granulomas in mice livers.

A continuous murine cell line (GRX) was obtained from fibrotic granulomas induced in C3H/HeN mice liver by experimental infection with Schistosoma mansoni. This anchorage-dependent line produces composite connective tissue/extracellular matrix, displays morphological characteristics of myofibroblasts, and can, under appropriate conditions, accumulate fat droplets. GRX cells produce viral particles of retrovirus type. We consider GRX cell line to be representative of liver connective tissue cells, responsible for fibroplasia in liver fibrotic and granulomatous reactions.

Animals↗
PubMed1985

Schistosoma mansoni: extramedullar eosinophil myelopoiesis induced by intraperitoneal glass implants in chronically infected mice.

Intraperitoneal glass implants in mice with chronic Schistosoma mansoni infections induce intense local myeloid reactions involving essentially myeloid granulocytes. The same phenomenon is not observed in normal mice nor in mice with acute schistosomal infection. An association of myelopoiesis with differentiated macrophages mobilized on glass implants and with dense ameboid cells located inside myeloid foci was detected. A macrophage-dependent induction of this eosinophil reaction is postulated.

Animals↗
PubMed1985

High-cholesterol diet induces altered responsiveness of rabbit arterial smooth muscle to noradrenaline.

The potential effect of feeding a high-cholesterol atherogenic diet (HCD) on in vitro responsiveness of rabbit arterial smooth muscle was investigated. The vasoconstrictor response produced by either exogenous or endogenous (field stimulation) noradrenaline was significantly depressed in isolated segments of ear artery after HCD as compared to regular diet fed animals. On the other hand no changes to high K+ could be observed in arterial segments after HCD as compared to regular diet fed rabbits. In addition, the alpha-adrenoceptor-mediated inotropic response and contraction of bladder smooth muscle showed only minor or no changes after HCD as compared to regular diet fed rabbits.

Adrenergic alpha-Agonists↗
PubMed1985

Brazilian Leishmania stocks phenotypically similar to Leishmania major.

Screening by enzyme electrophoresis of isolates of New World Leishmania from different geographic areas revealed a number of stocks with enzyme profiles different from those produced by reference strains of described subspecies of L. mexicana, L. braziliensis, and L. donovani. Analysis by six enzymes (aspartate aminotransferase; alanine aminotransferase; malate dehydrogenase; glucose-6-phosphate dehydrogenase; phosphoglucomutase; and glucose-phosphate isomerase) showed that these stocks have identical enzyme profiles and form a distinct zymodeme grouping. These observations were confirmed using the technique of schizodeme analysis and by comparing the k-DNA fingerprints produced by the restriction enzymes MspI, BspRI and AluI. The stocks were further analyzed by monoclonal antibodies and did not react with any of a large panel of L. mexicana, L. braziliensis, and L. donovani species- and/or subspecies-specific monoclonal antibodies using either an indirect radioimmune binding assay or immunofluorescence. These stocks did, however, react with a panel of monoclonal antibodies specific for L. major (formerly L. tropica major). Furthermore, the stocks could not be differentiated from L. major reference strains by enzyme electrophoresis nor could they be distinguished qualitatively from L. major based on their reactivity patterns using 10 Old World cutaneous species- and subspecies-specific monoclonal antibodies. Kinetoplast DNA restriction enzyme profiles, however, were different between these stocks and L. major reference strains. The implications of these results are discussed including the existence of other L. major-like stocks currently misidentified or uncharacterized.

Adult↗
PubMed1985

Subspecies- and species-specific antigens of Leishmania mexicana characterized by monoclonal antibodies.

Monoclonal antibodies have been produced that are specific for the reference stocks of Leishmania mexicana species and subspecies L. mexicana mexicana(L11, M379), L. mexicana amazonensis (WR303, H6, LV72), and L. mexicana pifanoi (L20). The specificities of these antibodies were confirmed by analyses employing an indirect radioimmune binding assay and 107 stocks of New World Leishmania. The molecules associated with these species- and subspecies-specific determinants have been characterized by Western blot analysis and consist of mainly low m.w. (11,000 to 50,000) membrane-associated components.

Animals↗
PubMed1984

Defining the beginning and end of KpnI family segments.

Comparison of the sequences at the ends of several newly cloned and full length members of the monkey KpnI family with one another and with previously described monkey and human segments defines the nucleotide sequence at the two termini. No terminal repeats either direct or inverted are noted within full length family members which may or may not be immediately flanked by direct repeats. At the 3' terminus, several family members have polyadenylation signals followed by a d(A)-rich stretch. The genomic frequency of segments within the full length element increases markedly from the 5' to the 3' terminus, consistent with the cloning of various truncated family members. One such truncated version joined to a low copy number DNA segment is inserted in monkey alpha-satellite where the combination appears to have been amplified in conjunction with the satellite itself.

Animals↗
PubMed1984

Tissue eosinophilia and Leishmania mexicana mexicana eosinophil interactions in murine cutaneous leishmaniasis.

Outbred albino mice were infected subcutaneously with 10(6) amastigotes of Leishmania mexicana mexicana and the subsequent lesions were evaluated by light and electron microscopy at various intervals after infection. The animals developed persistent nodules and a spectrum of lesions of variable size which was correlated with the host's ability to control the parasite in the tissue. During the acute phase of the disease the histopathological results showed an accumulation of granulocytes, some mononuclear phagocytes and a predominance of eosinophils as compared to other cell types. In this early acute phase, eosinophils were found in the tissue together with normal and degranulating mast cells. In the granulomatous inflammatory reaction of the chronic phases, there was infiltration of granulocytes parallel to parasite multiplication and the formation of parasitized vacuolated macrophages. The number of eosinophils was consistently greater than neutrophils, regardless of lesion type or number of parasites present in the tissue. During the acute reaction, the granulocytes apparently destroyed many parasites; however, there was an unvaryingly low level of phagocytosis of amastigotes during the chronic stages by both eosinophils and neutrophils. Neutrophils seemed to be more effective than eosinophils in the killing of ingested parasites. A close association between eosinophils and parasitized macrophages was seen in the chronic lesions; thus, eosinophils might contribute to parasite destruction through co-operation with macrophages.

Animals↗
PubMed1984

Schizodeme and zymodeme characterization of Leishmania in the investigation of foci of visceral and cutaneous leishmaniasis.

Leishmania parasites were isolated from humans and canines in foci of cutaneous and visceral leishmaniasis. After in vitro cultivation the parasites were examined by the following biochemical techniques: (i) restriction analysis of kinetoplast DNA (kDNA) also known as schizodeme analysis (Morel et al., 1980); (ii) zymodeme analysis (Barret et al., 1980); by agarose gel electrophoresis and (iii) isoelectricfocusing in polyacrylamide gels. The strains of cutaneous and visceralizing leishmanias studied could be differentiated by schizodeme analysis, using the endonuclease MspI, into three complexes agreeing with those accepted for human New World leishmaniasis. In the municipality of Rio de Janeiro, isolates from a focus of cutaneous leishmaniasis were identified as L. braziliensis braziliensis and from a focus of visceral leishmaniasis were identified as L. donovani by zymodeme characterization. Identical restriction enzyme profiles of kDNA from human and canine isolates indicated that in the cutaneous focus at Jacarepaguá, Rio de Janeiro, the same strain was probably circulating in both the canine and human populations. This suggests a possible role for dogs as a reservoir host for L. braziliensis braziliensis. In addition, our results confirm the importance of dogs as reservoirs in visceral leishmaniasis. The stability of the electrophoretic patterns of restriction digest ("fingerprints") of Leishmania kDNA as well as differences in the sensitivity of the techniques used were demonstrated. Strains from widely different geographical areas as well as strains maintained in vivo and in vitro showed identical kDNA restriction patterns, while strains showing similar banding patterns by enzyme electrophoresis could be differentiated by schizodeme analysis. These results demonstrate the usefulness of an integrated biochemical approach in the identification of Leishmania.

Animals↗