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Biomedical subjects

G Romeo

Publications and source records attributed to G Romeo.

At least 253 records · Page 14Linked to original sources
PubMed1988

Interferons-alpha/beta- and -gamma-resistant Friend cell variants exhibiting receptor sites for interferons but no induction of 2-5A synthetase and 67K protein kinase.

A number of Friend leukemia cell variants with a interferon-gamma (IFN-gamma)-resistant phenotype have been isolated. They appear resistant to the antiproliferative action of IFN-gamma and to the induction of the antiviral state assessed by Friend leukemia virus release and vesicular stomatitis virus yield. Selection was performed via a prolonged exposure to increasing amounts of highly purified recombinant IFN-gamma of wild-type Friend cells or of variant clones thereof already resistant to IFN-alpha/beta (Affabris et al., 1982, Virology 120, 441-452). Only the clones derived from IFN-alpha/beta-resistant variants showed a phenotype fully resistant to IFN-gamma treatment while keeping their previously acquired resistance to IFN-alpha/beta. These cells are not deficient in high-affinity receptors for IFN-gamma so that their resistant phenotype appears to be mediated by events distal to binding of IFN-gamma to its receptors. Furthermore, analysis of IFN-induced dsRNA-dependent 2-5A synthetase and 67K protein kinase enzymatic activities, biochemical markers for cellular responses to IFN, showed that both these activities were not induced in IFN-alpha/beta and IFN-gamma-resistant clones when treated with either type of IFN. Accordingly, no increased expression of 2-5A synthetase mRNA(s) could be detected by probing poly(A)+-enriched RNA from cells exposed to IFN-alpha/beta or IFN-gamma treatment with murine or human specific cDNAs. On the other hand, no major changes in restriction patterns of 2-5A synthetase gene(s) were observed in these variant cells by restriction endonuclease digestion and Southern blotting. In addition, analysis of 2-5A synthetase mRNA induction, performed on wild-type cells, showed that the kinetic of induction due to IFN-gamma treatment is slower than that obtained with IFN-alpha/beta.

2',5'-Oligoadenylate Synthetase↗
PubMed1988

Prevalence of mental retardation related to fragile X syndrome and other chromosomal abnormalities in the Republic of San Marino.

The prevalence of mental retardation related to chromosomal abnormalities, including fragile X syndrome, was studied among 2735 males aged between five and 20 years living in the Republic of San Marino. Five cases of chromosomal abnormalities were found, including one case with fragile X syndrome, with partial epilepsy and a CT scan showing a large arachnoid cyst in the posterior fossa. The prevalence of mental retardation due to chromosomal abnormality was 1.83 per 1000, and that due to fragile X syndrome was 0.37 per 1000. Although these findings relate to only a small population, they are the first from a Mediterranean area.

Adolescent↗
PubMed1988

Chromosomal assignments of human type I and type II cytokeratin genes to different chromosomes.

The chromosomal location of representative members of the type I and type II subfamilies of the cytokeratin multigene family was determined using specific cDNA probes in Southern blot hybridization with DNA from somatic cell hybrids. Our results show that the gene encoding human type II cytokeratin 4 resides on chromosome 12 and that encoding type I cytokeratin 15 is located on chromosome 17. The results indicate that cytokeratins are not concentrated in only one cluster. The possibility of the existence of separate type I and type II cytokeratin gene clusters is discussed.

Blotting, Southern↗
PubMed1988

Time-course of anti-Xa effects of calcium heparin and low-molecular-weight heparin given s.c.: insights for thrombosis prevention.

Thirty healthy volunteers underwent a pharmacokinetic study to control the effect of calcium heparin and low-molecular-weight heparin on coagulation factors. Activated partial thromboplastin time (aPTT), thrombin time (TT) and inhibition of activated factor X (Xa) were checked after a single subcutaneous administration of calcium heparin, 5000 IU (CH group); low-molecular-weight heparin 7500 AXaU (LMWH-LD group); and LMW heparin, 15,000 AXaU (LMWH-MD group). The mean values of aPTT rose significantly only after administration of LMW heparin (15,000 AXaU), while no relevant variations were observed after CH and LMWH-LD administration. The effects on TT were also very small and not relevant to an anticoagulant response. The Xa inhibitory effect exerted by the two LMW heparin doses proved substantially higher and longer-lasting than the effect of unfractioned heparin. A statistically significant Xa inhibition was still present 24 h after LMWH-MD administration and 16-20 h after LMWH-LD administration, while 6 h after CH administration no effect was detectable. The laboratory results confirm the marked antithrombophylic action, without relevant anticoagulant effects, already attributed by other authors to the new LMW heparin under study.

Adult↗
PubMed1988

Recombinations between IRP and cystic fibrosis.

A candidate gene for cystic fibrosis was recently isolated by selective cloning of HpaII-tiny-fragment islands; it maps considerably closer to CF than does MET or D7S8 (pJ3.11), and DNA polymorphisms from this region are in marked disequilibrium with CF. cDNA cloning has shown that this protein has a growth factor-like structure and shows homology to the murine and human proto-oncogene int-1; it is designated IRP (int-1-related protein). DNA sequences from the IRP locus that recognize RFLPs are proving to be highly informative for prenatal diagnosis. We report five crossovers that have been identified which occur either within the IRP locus or between IRP and CF; these recombinants demonstrate that CF maps between the DNA markers D7S8 and KM.19.

Cystic Fibrosis↗
PubMed1987

Nebulin and titin expression in Duchenne muscular dystrophy appears normal.

Monoclonal antibodies which recognize different epitopes on either titin or nebulin show normal staining patterns on frozen sections of three muscle biopsies of Duchenne muscular dystrophy (DMD). Gel electrophoresis and immunoblotting performed on two of these muscle biopsies show the normal pattern of titin and nebulin polypeptides. Since the donor of one of these biopsies has a large deletion of the 5'-region of the DMD gene, our results argue against the recent proposal that nebulin is the gene mutated in DMD.

Antibodies, Monoclonal↗
PubMed1987

Increased chloride efflux in fibroblasts from X-linked muscular dystrophies and clones from Duchenne carriers.

Previous studies have suggested an increased chloride membrane permeability in Duchenne muscular dystrophy (DMD) fibroblasts. We report that an increased chloride efflux with respect to controls is present not only in fibroblasts from DMD, but also from two other X-linked muscular dystrophies, Becker and Emery-Dreifuss, as well as in clones from DMD carrier females. The latter observation suggests that, at least in DMD, the increased chloride efflux phenotype might be subject to lyonization.

Cells, Cultured↗
PubMed1987

Disorders of the esophageal motor activity in atresia of the esophagus.

Esophageal dysfunction has been reported after successful repair of esophageal atresia but its nature has not been clearly defined. We studied esophageal motility in 20 newborns with esophageal atresia by recording intraluminal pressure of both proximal and distal segments. The investigation was made by pressure monitoring of the upper pouch via the mouth and of the distal segment via the gastrostomy. In all cases we found motility disorders. Two patients (12.5%) showed incomplete relaxation of the upper esophageal sphincter. The resting pressure of the esophageal body in both segments was constantly positive in all cases. Lower esophageal sphincter (LES) function was normal in all but two patients (16.7%) in whom the LES pressure was reduced and one case (8.4%) with incomplete relaxation of the LES. These studies suggest that motility disorders are also present in esophageal atresia before surgery.

Esophageal Atresia↗
PubMed1987

Isolation and characterization of a steroid sulfatase cDNA clone: genomic deletions in patients with X-chromosome-linked ichthyosis.

We have isolated several cDNA clones from a lambda gt11 expression library by screening with antibodies prepared against the microsomal enzyme steroid sulfatase, which is deficient in classical X-chromosome-linked ichthyosis patients. One of these clones (p422) has been assigned by mapping with a somatic cell hybrid panel and by in situ hybridization to Xp22.3. Clone p422 therefore has a coincident localization with the previously identified locus for steroid sulfatase expression in the region of the X chromosome escaping from inactivation. Twelve steroid sulfatase-deficient patients, including eight cases of classical ichthyosis, were found to be deleted for genomic sequences detected by the clone.

Chromosome Deletion↗
PubMed1987

Hereditary thrombophilia: identification of nonsense and missense mutations in the protein C gene.

The structure of the gene for protein C, an anticoagulant serine protease, was analyzed in 29 unrelated patients with hereditary thrombophilia and protein C deficiency. Gene deletion(s) or gross rearrangement(s) was not demonstrable by Southern blot hybridization to cDNA probes. However, two unrelated patients showed a variant restriction pattern after Pvu II or BamHI digestion, due to mutations in the last exon: analysis of their pedigrees, including three or seven heterozygotes, respectively, with approximately 50% reduction of both enzymatic and antigen level, showed the abnormal restriction pattern in all heterozygous individuals, but not in normal relatives. Cloning of protein C gene and sequencing of the last exon allowed us to identify a nonsense and a missense mutation, respectively. In the first case, codon 306 (CGA, arginine) is mutated to an inframe stop codon, thus generating a new Pvu II recognition site. In the second case, a missense mutation in the BamHI palindrome (GGATCC----GCATCC) leads to substitution of a key amino acid (a tryptophan to cysteine substitution at position 402), invariantly conserved in eukaryotic serine proteases. These point mutations may explain the protein C-deficiency phenotype of heterozygotes in the two pedigrees.

Amino Acid Sequence↗
PubMed1986

Kinetic alterations of cytochrome-c oxidase in cystic fibrosis.

We compared the kinetics of cytochrome-c oxidase (cytochrome-c:oxygen oxidoreductase, EC 1.9.3.1) in fibroblasts derived from normal and cystic fibrosis individuals. The Km of the enzyme for reduced cytochrome c was significantly increased in CF cells; the change, however, was observed only at temperatures above 25 degrees C. The Vmax values were comparable in both types of individuals.

Cells, Cultured↗