Biomedical subjects

R Guerriero

Publications and source records attributed to R Guerriero.

5 recordsLinked to original sources

PubMed1990

Blood coagulation factors in human embryonic-fetal development: preferential expression of the FVII/tissue factor pathway.

The expression of a number of blood coagulation factors (F) (FX, FIX, FVIII, FVII, alpha-, beta-, gamma-fibrinogen chains, protein C, and antithrombin III [AT III]) was analyzed at RNA and protein level in 5- to 10-week-old human embryos and fetuses. FX, FIX, and FVII were also analyzed at protein level. Total and poly(A)+ RNA, extracted from embryonic-fetal (FL) and adult liver (AL), were analyzed by dot and Northern blot hybridization with specific cDNA probes. The results indicate that: (1) the size of the messenger RNAs of these factors is equivalent in FL and AL; (2) in the 5- to 10-week period, their abundance in FL increases from 30% to 50% of the adult level except for FIX (from 2% to 10%) and FX (always 100% of the adult value). Western blot analysis of FIX, FX, and FVII in 5- to 10-week soluble liver proteins and 6- to 8-week plasma showed a low level of FIX versus a higher concentration of both FVII and FX, when compared with corresponding adult values, ie, a liver protein level of 10% versus 100% and a plasma concentration level of 10% versus 40%. Although little is known so far on the activity and the functional role of the clotting factors in early human ontogenic development, these studies suggest an activation of FX via the FVII/tissue factor activity rather than the FIXa/FVIIIa phospholipid complex in human embryonic and early fetal life.

Blood Coagulation Factors↗

PubMed1988

Multiple polymorphic sites in factor X locus.

The structure of factor X (FX) gene was analyzed in five FX deficient pedigrees with four different variants of the disease, as well as in 50 normal subjects. Genomic DNA from the deficient patients and the normal controls was digested with 12 restriction endonucleases and hybridized with a FX cDNA probe. The results seemingly exclude gross gene deletions or rearrangements in the deficient patients. A variety of polymorphic sites (ie, EcoRI, HindIII, PstI, PvuII, TaqI) was observed within the FX locus and their relative frequency was established. Intriguingly, a highly polymorphic region for the PvuII endonuclease was identified and located approximately 3 kilobases (kb) from the last 3' exon. These polymorphisms allowed us to analyze the allelic segregation in a FX deficient family and to identify a homozygous subject.

Adult↗

PubMed1985

Intragenic Factor IX restriction site polymorphism in hemophilia B variants.

This study includes 47 normal subjects and 25 hemophilia B patients without inhibitor(s), showing different factor IX coagulant activity and antigen levels. Genomic DNA, digested with various restriction endonucleases, was hybridized with two different factor IX probes, ie, the cDNA and the subgenomic probe for the intragenic TaqI polymorphic site. cDNA restriction patterns suggest absence of gross rearrangements and/or deletions in all hemophilic patients. The frequency of the X chromosome bearing the TaqI polymorphic site is 0.32 +/- 0.09 in hemophilic subjects v 0.36 +/- 0.06 in normal control subjects, the latter value being comparable to that reported for the normal British population. No association between this polymorphism and hemophilia B variants has been observed, thus indicating that a wide spectrum of mutations underlies this blood-clotting disorder and particularly each of its variants.

Cloning, Molecular↗

PubMed1985

Hemophilia B with inhibitor: molecular analysis of the subtotal deletion of the factor IX gene.

The structure of factor IX gene was analyzed in a hemophilia B patient with inhibitor. Genomic DNA, digested with a variety of restriction endonucleases, was hybridized with the cDNA and various genomic factor IX probes. A large subtotal deletion of the gene was observed. The borders of the deletion span from a approximately 125 nucleotide region within the last exon to an unknown domain at least 7.5 kb upstream from the first exon: it thus involves approximately 33 kb of the factor IX locus. The abnormal gene was inherited by the daughter of the propositus, who showed both the normal and the deleted allele.

Chromosome Deletion↗

PubMedDate not supplied

Haemoglobin switching in human embryos: asynchrony of zeta----alpha and epsilon----gamma-globin switches in primitive and definite erythropoietic lineage.

Haemoglobin switching in humans provides a unique model for investigating the mechanisms underlying expression of a developmentally regulated gene family. Numerous studies have focused on the switch from fetal to adult (that is, gamma----beta) globin, but little is known about the embryonic----fetal (that is, zeta----alpha and epsilon----gamma) switches, as well as the transition from 'primitive' yolk sac to 'definitive' liver erythropoiesis. Here we have studied the embryonic----fetal haemoglobin switches in yolk sac, liver and circulating blood erythroblasts from 25 embryos and 6 fetuses. Globin synthesis was also evaluated in purified 'primitive' and 'definitive' erythroblasts. Primitive erythroblasts synthesize essentially zeta and epsilon chains at 5 weeks and alpha- and epsilon-globin with a minor aliquot of zeta and gamma chains at 6-7 weeks, whereas definitive erythroblasts produce alpha and epsilon + gamma + beta-globin at 6 weeks but only alpha and gamma + beta chains from 8 weeks onward. In both lineages the zeta----alpha and the epsilon----gamma switches are asynchronous, the former preceding the latter. Furthermore, zeta- and beta-globin synthesis is restricted to primitive and definitive erythroblasts respectively. These findings are discussed in terms of a monoclonal model for haemoglobin switching in early human ontogeny.

Age Factors↗