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Biomedical subjects

L F Bernini

Publications and source records attributed to L F Bernini.

At least 55 records · Page 3Linked to original sources
PubMed1994

Hb Kurdistan [alpha 47(CE5)Asp-->Tyr], a new alpha chain variant in combination with beta (0)-thalassemia.

We have characterized the structural abnormality of a new alpha chain mutant found in a Kurdish family. The clinical and hematological investigation of eight individuals have shown that the alpha variant is associated with a beta(0)-thalassemia mutation (nonsense codon 39). The tryptic peptide map and sequencing of the abnormal peptide revealed the substitution of an aspartic acid by a tyrosine residue at position 47 of the alpha chain; furthermore, selective amplification and molecular analysis of both alpha genes have assigned the new mutation to the alpha 2 gene. The variant, named Hb Kurdistan, is clinically silent but the percentage of this hemoglobin found in the only double heterozygote for beta (0)-thalassemia and alpha-Kurdistan, presumably indicates a lower affinity of the abnormal chain for the beta polypeptides.

Adult↗
PubMed1993

Homology of a 130-kb region enclosing the alpha-globin gene cluster, the alpha-locus controlling region, and two non-globin genes in human and mouse.

The human alpha-globin gene cluster (30 kb) is embedded in a GC-rich isochore very close to the telomere of Chromosome (Chr) 16p. The alpha-Locus Controlling Region (alpha-LCR) is located upstream of the adult alpha-globin genes and has been shown to be essential for their expression. In this study we have been looking for expressed genes in the region upstream of the alpha-globin cluster to understand the role of the LCR-like element in the expression and replication timing of flanking gene clusters. We show that the upstream alpha-globin region is conserved over a 75-kb range and includes at least two oppositely transcribed non-globin genes, here referred to as Mid1 and Dist1. Complementary DNA sequences of 250 bp and 2.5 kb from Mid1 (coordinate -68) and Dist1 (coordinate -90 to -99), respectively, were isolated from human and mouse. The deduced partial amino acid sequences of these cDNAs are 81% and 95% identical for the Mid1 and Dist1 gene respectively. We have cloned a mouse cosmid "contig" which includes Dist1, Mid1, and the entire murine alpha-globin cluster. The murine homolog of the alpha-LCR was mapped upstream of the mouse globin genes at approximately the same position as in the human locus. Our results indicate that, in mouse and human, the alpha-globin loci and their flanking sequences are homologous over a range of at least 130 kb. The structural homology of this region in both mammals suggests also a functional one and indicates the mouse as a potential model for studying the role of the alpha-LCR controlling element in the regulation of expression and replication timing of the flanking gene clusters.

Amino Acid Sequence↗
PubMed1993

Purification and primary structure of ceratotoxin A and B, two antibacterial peptides from the female reproductive accessory glands of the medfly Ceratitis capitata (Insecta:Diptera).

In the present article we report the purification and the amino acid sequence of two antibacterial peptides present in the secretion of the female reproductive accessory glands of the dipteran insect Ceratitis capitata. Both peptides consist of 29 amino acid residues, are heat stable, strongly basic and differ from each other for the substitution of two amino acids. Their primary sequence and predicted secondary structure are related to other families of peptides known to have lytic and/or antibacterial activity. We propose the name ceratotoxins (from Ceratitis) for these antibacterial peptides.

Amino Acid Sequence↗
PubMed1992

Rapid identification by denaturing gradient gel electrophoresis of mutations in the gamma-globin gene promoters in non-deletion type HPFH.

We have outlined a fast, non-radioactive strategy to identify point mutations in the 5' flanking region of the gamma-globin genes using denaturing gradient gel electrophoresis (DGGE) of amplified DNA. In a sample of previously characterized carriers of non deletion-type hereditary persistence of fetal haemoglobin (HPFH) the different point mutations in both gamma gene promoters could be easily identified by DGGE of a 327 bp fragment. A 4 bp deletion at position -225 to -222 of the A gamma globin gene was unexpectedly found in several samples and shown to represent a frequent polymorphism. Analysis of a 681 bp fragment specific for the 5' region of the A gamma gene, showed that this can be used to determine the haplotype of the chromosome under study. This technique may be useful in the study of sequence variations associated with high Hb F expression in physiological and pathological conditions.

DNA Mutational Analysis↗
PubMed1991

Interaction of two different disorders in the beta-globin gene cluster associated with an increased hemoglobin F production: a novel deletion type of (G) gamma + ((A) gamma delta beta)(0)-thalassemia and a delta(0)-hereditary persistence of fetal hemoglobin determinant.

We report two different disorders of the beta-globin gene cluster segregating in a Belgian family: a novel deletion that results in (G) gamma + ((A) gamma delta beta)(0)-thalassemia (thal) and a heterocellular hereditary persistence of foetal hemoglobin of the Swiss type linked to a delta(0)-thal gene (delta (0)-HPFH). Heterozygosity for the heterocellular HPFH brings about a moderate (3.4% to 8.24%) increase of hemoglobin (Hb) F having a G gamma/A gamma ratio of 4:1, whereas carriers of the G gamma + ((A) gamma delta beta)(0)-thal deletion show in their peripheral blood a considerably higher (15%) percentage of Hb F. Both defects interact in the compound heterozygotes for G gamma + ((A) gamma delta beta)(0)-thal and delta(0)-HPFH producing a further increase (up to 24%) of fetal Hb consisting entirely of G gamma chains. Molecular characterization of the (G) gamma + ((A) gamma delta beta)(0)-thal by means of Southern analysis showed that the deletion spans about 50 kb, removing the 3' end of the A gamma-gene, the psi beta-, delta-, and beta-genes. A number of possible mechanisms leading to the overproduction of Hb F in HPFH and (G) gamma + ((A) gamma delta beta)(0)-thal will be discussed.

Adult↗
PubMed1991

Multiple recombination events are responsible for the heterogeneity of alpha(+)-thalassemia haplotypes among the forest tribes of Andhra Pradesh, India.

The presence of several polymorphic markers along the alpha-globin gene complex allows the identification of haplotypes associated with alpha-thalassemia determinants. These are found at very high frequencies in geographic areas where malaria is or has been endemic which suggests a positive selective role by the parasitic disease in favour of alpha(+)-thalassemia mutants. A population survey among forest tribal communities from Andhra Pradesh, India, revealed the prevalence and molecular heterogeneity of alpha(+)-thalassemia determinants presumably due to a long backdated malaria endemicity among these populations. Analysis of the tribal alpha-thalassemia haplotypes has shown a great degree of genetic heterogeneity which can be explained as the result of multiple recombination events in the presence of natural selection by malaria.

Alleles↗
PubMed1991

Homozygous beta+ thalassaemia owing to a mutation in the cleavage-polyadenylation sequence of the human beta globin gene.

A mild, non-transfusion dependent, beta thalassaemia phenotype is described in a Dutch patient homozygous for a mutation in the cleavage-polyadenylation sequence of the beta globin gene. The molecular basis of the mutation, AATAAA greater than AATGAA, was determined using denaturing gradient gel electrophoresis (DGGE) and direct sequencing of genomic DNA amplified by the polymerase chain reaction (PCR). Different fragments of the beta globin gene were amplified and analysed on DGGE for the presence of mutations. The fragment with an abnormal melting behaviour was reamplified and the base substitution in the polyadenylation sequence was identified by direct sequencing.

Adolescent↗
PubMed1990

Nucleotide sequence of the Belgian G gamma+(A gamma delta beta)0-thalassemia deletion breakpoint suggests a common mechanism for a number of such recombination events.

Various types of thalassemia or hereditary persistence of fetal hemoglobin (HPFH) are caused by deletions at the human beta-globin gene cluster. Many of these molecular lesions show a clear clustering as far as size and location of their breakpoints are concerned. This might indicate common recombination mechanisms responsible for the generation of these deletions. The Belgian G gamma+(A gamma delta beta)zero-thalassemia results from a large deletion spanning the beta-globin gene cluster 3' of the A gamma gene. The extent of this deletion, analyzed by field-inversion gel electrophoresis, is approximately 50 kb and is very similar to that of the Indian HPFH (G gamma A gamma HPFH III) previously characterized by P. S. Henthorn et al. (1986). Proc. Natl. Acad. Sci. USA 83: 5194-5198. Isolation of the deletion junction of the Belgian G gamma+(A gamma delta beta)zero-thalassemia by means of inverse polymerase chain reaction confirmed a very close relationship between these two independent deletions. The 3' breakpoint of the Belgian deletion is located at the midpoint of a 160-bp palindrome, only four nucleotides 5' from the correspondent endpoint of the Indian HPFH.

Base Sequence↗
PubMed1990

Denaturing gradient gel electrophoresis and direct sequencing of PCR amplified genomic DNA: a rapid and reliable diagnostic approach to beta thalassaemia.

The analysis of polymerase chain reaction (PCR)-amplified beta-globin DNA with allele-specific oligonucleotide (ASO) probes reveals a very heterogeneous spectrum of beta-thalassaemia in the Netherlands. However about 20% of the beta-thalassemia mutations cannot be identified with this approach. The combination of specific amplification of certain regions of the beta-globin gene with denaturing gradient gel electrophoresis (DGGE) allowed us to rapidly localize several of these mutations to specific regions of the gene, which were again amplified and directly sequenced. We believe that the combination of DGGE and the direct sequence determination of PCR amplified genomic DNA represents a valid alternative to the 'ASO probes' approach, especially in countries where a very heterogeneous spectrum of beta-thalassaemia mutations occurs.

Base Sequence↗
PubMed1990

Hb J-Anatolia [alpha 61(E10)Lys----Thr]: structural characterization and gene localization of a new alpha chain variant.

We report the characterization of a new hemoglobin variant having a single amino acid substitution (Lys----Thr) at position 61 of the alpha chain. In addition to the structural analysis, we also describe the strategy used for the identification of the base substitution and the localization of the defect at the gene level using polymerase chain reaction and hybridization with allele-specific oligonucleotides.

Alleles↗
PubMed1989

[Combined alpha and beta thalassemia in a Chinese family in The Netherlands].

In a Chinese family living in The Netherlands alpha 0- and beta-thalassaemia occur singly and in combined form. All members of the family are moderately anaemic and show the characteristic haematological abnormalities of thalassaemia carriers. The nature of the alpha 0-thalassaemia defect was shown at the molecular level to be a deletion of the South East Asian type, which removes about 20 kb of DNA spanning both alpha genes in cis. The chromosome carrying the beta-thalassaemia mutation was identified using RFLPs (restriction enzyme fragment length polymorphisms). The combined heterozygosity for alpha 0- and beta-thalassaemia results in a phenotype virtually indistinguishable from heterozygous beta-thalassaemia, except for the almost balanced globin chain synthesis.

Adolescent↗
PubMed1989

[Prenatal fetal blood group determination using chorionic villi biopsy].

The presence or absence of Rhesus D, c and Kell antigens on foetal red blood cells was determined in the first trimester of pregnancy on erythrocytes obtained by chorionic villi sampling. Pregnancies in 15 severely sensitized women (9 Rh D, 5 Kell and I Rh c) with a poor obstetric history and a partner heterozygous for the offending antigen were examined. A conclusive diagnosis could be made in 13 of the 15 cases studied.

Blood Group Antigens↗
PubMed1989

A novel delta zero-thalassemia arising from a frameshift insertion, detected by direct sequencing of enzymatically amplified DNA.

We describe a novel mutation in the delta globin gene of a compound heterozygote for delta o thalassemia and a deletion type G gamma + (A gamma delta beta) zero thalassemia. The delta was amplified using the polymerase chain reaction (PCR), and the amplified material was used in a direct sequencing experiment. The nucleotide sequence of the mutant delta gene showed that the insertion of an extra nucleotide at the third position of codon 91 in the second exon, which gives rise to a premature stop codon at position 94, leads to the silencing of this gene. The presence of the mutation in the carriers of delta-thalassemia in this family was confirmed by dot blot hybridization. A possible model for the insertion of the extra nucleotide is discussed.

Base Sequence↗