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Biomedical subjects

G Fiorelli

Publications and source records attributed to G Fiorelli.

At least 109 records · Page 6Linked to original sources
PubMed1994

Molecular characterisation of an Italian G6PD variant responsible for chronic non-spherocytic haemolytic anaemia.

An Italian deficient G6PD variant associated with chronic non-spherocytic haemolytic anaemia (CNSHA) was biochemically characterised and studied at molecular level. Single-strand conformation polymorphism (SSCP) analysis led to the identification of an abnormal migration pattern of an amplified fragment encompassing exons 10 and 11 of the G6PD gene. Sequence analysis of both strands using an automated fluorescent DNA sequencer revealed a G-->A transition at nt. position 1246 in exon 10. A C-->T substitution at nt. 1311 in exon 11 was also found, which has already been described as a silent mutation common in Caucasians. The 1246 G-->A mutation has been described only in a Japanese subject with CNSHA (G6PD Tokyo) not associated with the 1311T polymorphism, suggesting that this mutation may have arisen independently in Europe and Asia.

Adult↗
PubMed1994

Binding and growth-inhibitory effect of heparin and oligo-heparin (2kDa) in Balb/c 3T3 cells: lack of effect on PDGF- or serum-induced inositol lipid turnover.

1. The ability of heparins (bovine heparin sm 1026, Av. mol. wt. 36.9 kDa and bovine heparin EP 756, Av. mol. wt. 12.9 kDa) and heparin fractions of different molecular weights (low molecular weight heparin, LMW 2123/OP, Av. mol. wt. 4.5 kDa and oligo-heparin, Av. mol. wt. 2 kDa) to inhibit the proliferation and signalling of Balb/c 3T3 fibroblasts was investigated. 2. Heparin and heparin fractions of 4.5 and 2 kDa significantly inhibited DNA synthesis as monitored by [2H]-thymidine incorporation. 3. 3H-labelled heparin fractions of 4.5 and 2 kDa were prepared by gel-chromatography fractionation on Sephadex G-75 of an 3H-labelled commercial heparin after treatment with heparinase. 4. The binding of unfractionated and oligo-heparin of 2 kDa to Balb/c 3T3 fibroblasts was studied; we determined the specificity of heparin and oligo-heparin binding to the cells by means of displacement of bound 3H-labelled compound in response to increasing concentrations of unlabelled compounds. Scatchard analysis of binding data obtained using [3H]-heparin as ligand revealed the presence of a single class of high affinity binding sites (Kd = 28 nM) for heparin. Scatchard analysis of binding data obtained using [3H]-oligo-heparin as ligand revealed the presence of a single class of low affinity binding sites (Kd = 3.2 microM) for oligo-heparin. 5. In addition heparin displaced [3H]-oligo-heparin at a concentration of approximately 100 fold of the Kd determined in displacement studies. Furthermore, oligo-heparin significantly displaced [3H]-heparin at a concentration of approximately 10 fold of the Kd determined by displacement studies. 6. Both heparin and oligo-heparin exert their inhibitory effects on Balb/c 3T3 DNA synthesis stimulated by PDGF or serum. However these molecules did not affect the inositol lipid turnover triggered by PDGF at a concentration which did not produce maximal response. The increase of inositol phosphate metabolism produced by 20% serum was also unaffected by heparin. This concentration of serum elicited a response comparable to that induced by a submaximal concentration of PDGF.

3T3 Cells↗
PubMed1994

Insulin-like growth factor-I (IGF-I) and its binding protein IGFBP-4 in human prostatic hyperplastic tissue: gene expression and its cellular localization.

It has been previously reported that 1) type I insulin-like growth factor (IGF) receptors are present in the human prostatic tissue; 2) IGF-I receptors are mainly localized in the epithelial cells; 3) IGF-I is a mitogen for prostatic epithelial cells in culture; and 4) IGF-binding proteins (IGFBPs) are released by these cells in the conditioned medium. To add information on the mechanism of IGF-I action in the human prostate, we studied the expression and cellular localization of mRNA encoding IGF-I and IGFBP-4 in human prostatic hyperplastic (BPH) tissue. Northern analysis of total RNA extracted from BPH tissues with cDNA probes containing the entire coding regions for IGF-I and IGFBP-4 documented the presence of multiple IGF-I mRNA transcripts with lengths of 7.5, 1.7, 1.3, and 1.1 kilobases and a single 2.1-kilobase transcript of IGFBP-4 mRNA. In situ hybridization with the cDNA probes used for Northern analysis and with cRNA probes synthesized from the respective cDNA demonstrated that IGF-I mRNA was only localized in the stromal cells, whereas IGFBP-4 mRNA was predominantly expressed by epithelial cells. In addition, immunoreactive IGF-I was measured in BPH tissue extracts after acidification and reverse phase chromatography. The mean (+/- SD) IGF-I content of six BPH tissues was 28.1 +/- 4.0 ng/g tissue. Our results suggest that in the human prostate, the locally secreted IGF-I exerts its principal biological effects with a paracrine mode of action and demonstrate that IGFBP-4 is mainly expressed by IGF-I target cells.

Carrier Proteins↗
PubMed1994

Dopamine D2 receptor gene expression and binding sites in adrenal medulla and pheochromocytoma.

To determine whether dopamine D2 receptors are present in normal and neoplastic chromaffin tissues, 10 pheochromocytomas and 5 human adrenal glands were studied. Dopamine D2 receptor messenger ribonucleic acid corresponding to a single band of approximately 2.5 kilobases was detected in both pheochromocytoma and human adrenal gland by Northern blot analysis. D2 receptor messenger ribonucleic acid levels determined by dot blot analysis were 3.1-fold lower in human adrenal medullas than in pheochromocytomas (P < 0.001). Simultaneous Scatchard analysis of [3H]spiperone binding experiments demonstrated the presence of two different binding sites in membrane preparations from bovine adrenal medullas [R1: Kd = 0.14 nmol/L; binding capacity (Bmax) = 6.2 fmol/mg protein: R2: Kd = 16 nmol/L; Bmax = 223 fmol/mg protein]. Similarly, two binding sites were present in membrane preparations from pheochromocytomas (R1: Kd = 0.39 nmol/L; R2: Kd = 61 nmol/L]. Binding capacities were greatly variable among pheochromocytomas (R1: Bmax = 12.0-372.5 fmol/mg protein; R2: Bmax = 1,000-11,586 fmol/mg protein). The relative potencies of different compounds to displace [3H]spiperone were spiperone > domperidone > (+)-butaclamol > quinpirole > SCH 23390 in bovine adrenal medulla, and spiperone >> domperidone > quinpirole > (+)-butaclamol > SCH 23390 in pheochromocytoma. We conclude that dopamine D2 receptors are synthesized in human adrenal medulla and pheochromocytoma tissues.

Adrenal Gland Neoplasms↗
PubMed1993

Alternative splicing of human G6PD messenger RNA in K562 cells but not in cultured erythroblasts.

The biochemical properties of glucose-6-phosphate dehydrogenase (G6PD) vary in different tissues, and different protein isoforms of the enzyme have been described. Alternative splicing of G6PD intron VII has been detected in transformed lymphoblasts, granulocytes and spermatocytes; the function of this mRNA species is still unknown. We developed a PCR for detecting alternatively spliced G6PD mRNA in K562 and in erythroblasts at different stage of maturation obtained from human peripheral BFU-E in order to evaluate a possible physiological role during erythroid maturation. Trace events of alternative splicing of G6PD intron VII sequences were observed in K562 cells but not in BFU-E-derived erythroid precursors; we consider this phenomenon a non-functional activity in the cells analysed.

Base Sequence↗
PubMed1993

Geographical variation in prevalence of hepatitis B virus DNA in HBsAg negative patients.

AIMS--To study the geographical variation of the prevalence of hepatitis B virus (HBV) DNA in hepatitis B surface antigen (HBsAg) negative subjects. METHODS--A nested polymerase chain reaction (PCR) assay was used to amplify the core region of HBV. The assay was able to detect 10 molecules of a full length HBV plasmid. RESULTS--When applied to HBsAg negative paraffin wax embedded liver samples from Italy, Hong Kong, and the United Kingdom, a geographical variation in the prevalence of HBV-DNA positivity was noted. Two of 18 (11%) of Italian samples and 2/29 (6.9%) of Hong Kong samples were positive for HBV-DNA while none of the 70 cases from the United Kingdom was positive by nested PCR. Contamination by plasmid DNA was excluded using a novel method based on heteroduplex formation. One HBV-DNA positive case had idiopathic chronic active hepatitis, but the diagnoses in the other three HBV-DNA positive cases did not suggest any aetiological connection between HBV-DNA positivity and liver pathology. CONCLUSIONS--HBV-DNA could be detected in the liver tissues of a proportion of HBsAg negative subjects. The prevalence of such cases is related to the endemic rate of a geographical region. The use of HBV PCR on paraffin wax embedded tissues will be valuable for future studies on the molecular epidemiology of HBV.

Base Sequence↗
PubMed1993

Cyclic adenosine monophosphate stimulates insulin-like growth factor binding protein-4 and its messenger ribonucleic acid in a clonal endothelial cell line.

Endothelial cells regulate the passage of insulin-like growth factors (IGFs) or IGFs complexed to IGF-binding proteins (IGFBPs) from plasma to the extravascular space, and in addition respond to plasma and tissue IGFs. The IGFBPs are thought to determine the availability and localization of IGFs to tissues, and to inhibit or potentiate their biological activity. Because of the potential importance of the IGF system in endothelial cell pathophysiology, and because IGFBPs modulate IGF action, we have characterized the IGFBPs synthesized by a clonal endothelial cell line (BPE-1) established from bovine parathyroid microvessels. The only IGFBPs identified by ligand blotting in media conditioned by BPE-1 cells were N-glycosylated 28 kilodalton and non-N-glycosylated 24 kilodalton IGFBP-4 species. Both forms were immunoprecipitated by antibodies to human IGFBP-4. Northern blot hybridization of BPE-1 RNA identified messenger RNAs for IGFBP-4 and IGFBP-6, but not for IGFBP-1, 2, 3, or 5. Agents that increase cAMP including forskolin, (Bu)2cAMP, isobutyl-methylxanthine, and histamine increased IGFBP-4 and IGFBP-4 messenger RNA in BPE-1 cells 2- to 5-fold and 2- to 3-fold, respectively, similar to results previously reported in human osteosarcoma cells and fibroblasts. Increased IGFBP-4 was detected in BPE-1 media 6 h after forskolin addition and was maximal after 24 h. Maximal stimulation (6- to 9-fold) was observed with 1-30 microM forskolin. IGFBP-4 also was the predominant IGFBP synthesized by two other endothelial cell lines, a clonal cell line established from bovine bone microvessels, and a polyclonal cell line established from calf pulmonary artery. Further study is required to determine the role of endothelial cell IGFBP-4 on endothelium and adjacent cells, and on the transport of IGFs from plasma to specific subendothelial sites.

1-Methyl-3-isobutylxanthine↗
PubMed1992

Rapid isolation of glucose-6-phosphate dehydrogenase from human erythrocytes by combined affinity and anion-exchange chromatography for biochemical characterization of variants.

A new method is presented for the purification of human glucose-6-phosphate dehydrogenase (G6PD) using affinity chromatography with 2'5'-ADP-Sepharose 4B followed by automated ion-exchange chromatography with DEAE 5PW. This rapid method allows a high recovery of enzyme activity from even a small amount of blood; the yield is about 90% after the first purification step and 70% at the end of the procedure. There is an excellent reproducibility of the kinetic parameters and optimal biochemical characterization of G6PD is achieved even for variants associated with severe enzyme deficiency (e.g. G6PD Mediterranean).

Chromatography, Affinity↗
PubMed1992

Binding and suppressive activity of human recombinant ferritins on erythroid cells.

We studied the relation between ferritin cellular binding and suppressive activity of recombinant H- and L-ferritin on human erythroid cells at different proliferation/differentiation phases. L-ferritin failed to show any suppressive activity or detectable binding to erythroblasts at any stage of maturation. In contrast, H-ferritin demonstrated binding to erythroblasts derived from peripheral BFU-E cells which increased steadily between 7-14 days of culture up to 15,000 molecules per cell. Reticulocytes and erythrocytes failed to bind either L- or H-ferritin. H-ferritin suppressed BFU-E colony formation and reduced K562 cell proliferation at nanomolar concentrations. This suggests that the expression of H-ferritin binding sites is modulated by cellular proliferation and differentiation, that cells expressing H-ferritin binding sites are sensitive to ferritin suppressive activity and that a causal relation exists between ferritin cellular binding and suppressive activity.

Binding Sites↗
PubMed1992

Survival and prognostic factors in 212 Italian patients with genetic hemochromatosis.

Two hundred twelve Italian patients with genetic hemochromatosis (181 men, mean age 50 +/- 11 yr; and 31 women, mean age 49 +/- 10 yr) were followed for a median period of 44 mo (range = 3 to 218 mo). Alcohol abuse was present in 31 subjects (15%), and chronic HBV and HCV infection were seen in 19 (9%) and 35 (24%) of 145 cases tested, respectively. Twenty-four patients (11%) had concomitant beta-thalassemia trait. Liver biopsy revealed cirrhosis in 146 and a noncirrhotic pattern in the other 66. Perls' stain was degree III in 37 patients and IV in 171 patients. One hundred eighty-five patients underwent weekly venesection, and iron depletion was achieved in 122 cases after total iron removal of 3 to 41 gm. Death occurred in 44 patients after 3 to 198 mo and was due to hepatocellular carcinoma in 20 cases, liver failure in 10, extrahepatic cancer in six, heart failure in three and hemochromatosis unrelated causes in five. Cancer has developed in seven other patients still alive (hepatocellular in five and extrahepatic in two). No deaths were observed among noncirrhotic patients; cumulative survival rates in cirrhotic patients were 85%, 75%, 60% and 47% at 3, 5, 8 and 10 yr, respectively. Univariate analysis in the 146 cirrhotic patients showed that age greater than 60 yr, alcohol abuse, cardiomyopathy, skin pigmentation, portal hypertension, hypoalbuminemia, hypergammaglobulinemia and Child class B or C had significant negative prognostic value. At multivariate analysis, only alcohol abuse, gamma-globulins greater than 2.0 gm/dl and Child class B or C maintained their negative prognostic values (p less than 0.01, hazard ratio 2.7; p less than 0.001, hazard ratio 2.8; and p less than 0.001, hazard ratio 4.3, respectively).

Adult↗
PubMed1992

Hepatitis C virus and porphyria cutanea tarda: evidence of a strong association.

Porphyria cutanea tarda in human beings is believed to be due to reduced hepatic uroporphyrinogen decarboxylase activity. However, extrinsic factors such as alcohol abuse and drug intake are required for clinical manifestation of the disease. In addition to typical cutaneous lesions, patients with porphyria cutanea tarda usually have chronic liver disease and moderate iron overload. Of 74 Italian patients with porphyria cutanea tarda, hepatitis C virus antibodies were detected in 76% by enzyme-linked immunoassay and in 82% by recombinant immunoblot assay. Viral genome, studied with nested polymerase chain reaction, was found in the sera of 49 subjects--47 positive and 2 indeterminate on recombinant immunoblot assay. Five percent of the patients were HBsAg-positive, and about 40% had had past hepatitis B contacts. Alcohol abuse was present in 38%. Liver biopsies performed in 42 patients showed chronic persistent hepatitis in 7 patients, chronic active hepatitis in 22 patients, fibrosis in three patients and cirrhosis in 10 patients. Hepatitis C virus antibody was detected in 100% of patients with chronic active hepatitis and in about 80% of all other groups. Alcohol abuse was more frequent in patients with cirrhosis (80%) than in the other groups. In Italian patients with porphyria cutanea tarda, the prevalence of hepatitis C virus infection was very high, comparable to that in non-A, non-B hepatitis and high-risk patient groups. Hepatitis C virus is probably the main pathogenetic factor of the liver disease of patients with porphyria cutanea tarda.

Alcoholism↗