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Biomedical subjects

L Luzzatto

Publications and source records attributed to L Luzzatto.

At least 163 records · Page 9Linked to original sources
PubMed1988

An extensive search for RFLP in the human glucose-6-phosphate dehydrogenase locus has revealed a silent mutation in the coding sequence.

The genetic polymorphism of an approximately 100-kb DNA region comprising and flanking the glucose-6-phosphate dehydrogenase (G6PD) gene on human chromosome Xq28 has been analyzed in detail. By using 14 unique sequence probes and 18 restriction enzymes, we have characterized 257 restriction fragments or 370 restriction sites. On testing 12-57 individual X chromosomes, all sites but one were nonpolymorphic. However, a PstI site that maps to exon 10 of the G6PD gene, which is still monomorphic in all British and Italian subjects tested, is polymorphic in west-African people. Specifically, it is absent from 22% of Nigerian X chromosomes. By sequence analysis we have shown that the absence of this PstI site results from a G----A replacement at position 1116, corresponding to the third base of a glutamine codon; no amino acid change is produced in the protein. Thus, a polymorphic silent mutation is demonstrated in a human gene.

DNA Restriction Enzymes↗
PubMed1988

Lymphomatoid granulomatosis--evidence of a clonal T-cell origin and an association with lethal midline granuloma.

Lymphomatoid granulomatosis and lethal midline granuloma are both characterized histologically by atypical pleomorphic angiocentric infiltrates. Whether these conditions are malignant lymphoproliferative disorders remains controversial. Here we report the results of studies carried out in a patient with coeliac disease, who developed recurrent self-healing subcutaneous nodules with the histological changes of lymphomatoid granulomatosis and an invasive nasal tumour with the histological features of lethal midline granuloma. The patient subsequently also developed an erythrophagocytic syndrome. Immunocytochemical labelling of both cutaneous and nasal lesions demonstrated a predominant population of T cells with a CD4-negative CD8-positive phenotype. Analysis of DNA from cutaneous tissue revealed a discrete rearrangement of the beta and gamma T-cell receptor genes. These findings suggest that lymphomatoid granulomatosis is a clonal T-cell lymphoproliferative disorder and its association with lethal midline granuloma indicates that both conditions may have a common histogenesis.

Celiac Disease↗
PubMed1988

The establishment of cell lines from chronic B cell leukaemias: evidence of leukaemic origin by karyotypic abnormalities and Ig gene rearrangement.

We have studied the capacity of peripheral blood cells from 26 chronic B cell leukaemias to proliferate continuously in culture; 72 attempts to establish cell lines were made. The cells were treated in vitro with or without stimulating agents: Epstein-Barr virus (EBV) and/or phorbol-ester (TPA) were the most frequently used. Fourteen cell lines of continuous growth were established from cells from 11 patients, but only four of these were proven to be derived from the original leukaemic cells. Only in the latter four lines were the karyotypic abnormalities and the patterns of immunoglobulin (Ig)-gene rearrangements identical to those found in the patients' leukaemic cells. On the other 10 lines, five had both kappa- and lambda-producing cells, and the remaining five, despite showing light-chain restriction, were proved to be non-leukaemic clones by comparing the Ig-gene rearrangement patterns before and after culture. Three of the four leukaemic cell lines (JVM-2, JVM-3 and JVM-13) were induced by EBV + TPA and derived from prolymphocytic leukaemia (PLL) cases; the fourth (JVM-14) originated from a case of chronic lymphocytic leukaemia (CLL) with increased percentage of prolymphocytes whose cells were stimulated in vitro with EBV. The immunophenotype of the three PLL lines is more mature than that of the original prolymphocytes, as shown by a reduction in surface-Ig and FMC7 expression, enhancement of cytoplasmic-Ig and increase in CD38- and transferrin receptor-positive cells. The cells from line JVM-14 retained the CD5-antigen, a marker of CLL. This study suggests that PLL and some CLL clones are arrested at a stage of maturation ideally suited to be triggered to continuous proliferation in culture. The presence of consistent chromosomal abnormalities in PLL may offer an alternative explanation for the greater proliferative potential of these cells in vitro.

Antigens, Neoplasm↗
PubMed1987

Establishment and characterization of three new malignant lymphoid cell lines.

We have established 3 new EBV-negative cell lines, designated Sc-1, Ri-1 and Ci-1, from patients with B-cell lymphoma/leukemia. We characterized them by cytogenetics and by study of surface membrane antigens with a panel of monoclonal antibodies (MAbs), surface and cytoplasmic immunoglobulin (Ig) expression and Ig heavy- and light-chain genes. All 3 lines had a 14q+ abnormality. Ri-1 also had translocations involving chromosomes 2, 8 and 18. Ci-1 also had abnormalities involving chromosomes 2, 8 and 22 and its karyotype was 46, XX, t(2;8), t(14;22). The t(2;8) had the same breakpoints as those reported in some cases of Burkitt's lymphoma. We also studied a classical Ph1-positive cell line previously established by Pegoraro et al. (1983) and designated BV173. The phenotypes of these 4 lines based on Ig expression and marker studies correlated well with their respective genotypes. Our results are in keeping with the notion that leukaemic cell populations are clonal expansions of cells "frozen" at a particular stage in their differentiation. Specifically, BV173 cells are at an early stage of B-cell differentiation, Ri-1 and Ci-1 cells are at intermediate stages and Sc-1 cells are at a relatively late stage in the B-cell lineage.

Adult↗
PubMed1987

Neonatal jaundice and severity of glucose-6-phosphate dehydrogenase deficiency in Sardinian babies.

We have investigated the association of neonatal jaundice (NNJ) and G6PD deficiency in consecutive births in a Northern Sardinian hospital. After excluding known causes for NNJ, and after correcting for the incidence of NNJ from unknown causes, we estimated that 20% of G6PD deficient male newborns develop NNJ resulting from their enzyme deficiency. By analyzing in detail 100 G6PD deficient babies we found no differences in birth weight or haemoglobin level between those without and those with NNJ, four of whom required exchange transfusion. We further showed by an accurate quantitative method that the residual G6PD enzyme activity was not significantly lower in G6PD deficient babies with NNJ compared to G6PD deficient babies without NNJ.

Bilirubin↗
PubMed1987

Alpha, beta and gamma T-cell receptor genes: rearrangements correlate with haematological phenotype in T cell leukaemias.

We have studied the arrangement of the alpha, beta and gamma T cell receptor (TCR) genes in 27 patients with T cell lymphoproliferative disorders. Nine patients had acute lymphoblastic leukaemia (T-ALL), nine patients had prolymphocytic leukaemia (PLL), six patients presented with a T-CLL/T-lymphocytosis syndrome, two patients had Sezary syndrome (SS) and one patient had HTLV-I positive T-cell leukaemia/lymphoma (ATLL). alpha TCR gene rearrangement could be demonstrated by the use of three available probes in only one case. By contrast, both beta and gamma TCR gene rearrangement could be demonstrated by Southern blot analysis of DNA samples digested with appropriate restriction enzymes in the majority of cases. In general, when rearrangements were present they involved both alleles. The proportion of rearranged chromosomes was lower in T-ALL than in other forms of T-cell leukaemia and it was lower in cases with the CD4-/CD8+ phenotype than in those with a CD4+/CD8- phenotype. In three out of 34 cases of B-cell leukaemia the TCR beta-gene but not the TCR gamma-gene was rearranged, just as in two out of 26 cases of T-cell leukaemia the immunoglobulin (Ig) heavy chain but not the light chain genes were rearranged. These data suggest that development of the machinery required for gene rearrangement may precede commitment to B or T cell lineage. The use of this technique is especially useful for the classification of cases of ALL in which the cells are negative with respect to most current phenotypic markers and in cases of T cell lymphocytosis in which the finding of a gene rearrangement identifies a monoclonal cell population.

Adolescent↗
PubMed1987

'Pseudo-lymphoid' leukaemia with unusual features: ultrastructural, immunological, cytogenetic and molecular studies.

An unusual case of 'pseudo-lymphoid' leukaemia is described. The leukaemic cells resembled small, mature lymphocytes but lacked B- and T-cell membrane markers as well as immunoglobulin (Ig) and T-cell receptor gene rearrangements. They showed, instead, features of early myeloid cells since they expressed 2 myeloid antigens, CDW13 and My9, and displayed peroxidase activity demonstrable by electron microscopy (EM) on unfixed cells. Cytogenetic studies showed monosomy 5, t(4;17) (p12;p11), t(2;3)(p23;q14) and an abnormal chromosome 12. Abnormalities of chromosomes 4 and 5 have been previously associated with 'pseudo-lymphoid' leukaemias. This case illustrates the value of sensitive methods for the characterization of blast cells and for the precise diagnosis of leukaemias with apparent 'lymphoid' morphology.

Antibodies, Monoclonal↗
PubMed1987

Immunoglobulin gene rearrangements in hairy cell leukemia and other chronic B cell lymphoproliferative disorders.

Immunoglobulin gene rearrangements have been investigated in 11 patients with hairy cell leukemia (HCL), 11 with prolymphocytic Leukemia (PLL), and 34 with chronic lymphocytic leukemia (CLL). Heavy and Light Ig chain gene probes have been used, and Ig genes were found in a rearranged configuration in all cases. Production of kappa and lambda light chains correlated with the respective gene rearrangements. With respect to the heavy chain locus, we found that in 6 of 21 cases of kappa-producing CLL only one allele was rearranged, whereas both alleles were rearranged in nearly all cases of lambda-producing CLL and either kappa- or lambda-producing HCL and PLL. Our data confirm the B cell nature of HCL and lead us to suggest that HCL derives from the clonal expansion of a cell at a later developmental stage than in CLL and PLL.

B-Lymphocytes↗
PubMed1986

Two new cell lines from B-prolymphocytic leukaemia: characterization by morphology, immunological markers, karyotype and Ig gene rearrangement.

Leukaemic cells from 2 patients with B-prolymphocytic leukaemia were immortalized in vitro by means of Epstein-Barr virus and phorbol-ester TPA. The resulting cell lines, named JVM-2 and JVM-3, have been growing continuously in liquid culture for more than one year. JVM-2 is characterized cytogenetically by t(11;14)(q13; q32), and JVM-3 by trisomy 12. The immunoglobulin (Ig) heavy- and light-chain genes showed the same pattern of rearrangement in both lines as in the original prolymphocytes from each case. The cells from these lines showed a spectrum of morphological and immunological features corresponding to different stages of B-cell maturation. The expression of Ig, IgM-lambda in JVM-2 and IgMD-K in JVM-3, changed from a predominantly membrane pattern in the original cells to a cytoplasmic one in the cell lines. By comparison with their original progenitors, the cells from both lines showed reduced reactivity with the monoclonal antibody (MAb) FMC7, and increased expression of the antigens recognized by the MAbs OKT10, alpha-Tac, FMC53 and Ki-I. The availability of cell lines from this rare type of lymphoid leukaemia offers a potential tool for the study of molecular events associated with the expression of Ig and other antigens by neoplastic cells.

B-Lymphocytes↗
PubMed1986

Isolation of human glucose-6-phosphate dehydrogenase (G6PD) cDNA clones: primary structure of the protein and unusual 5' non-coding region.

Glucose-6-phosphate dehydrogenase (G6PD) is an ubiquitous enzyme which by determining the NADPH level has a crucial role in NADPH-mediated reductive processes in all cells (1). The structural gene for G6PD, Gd, is X-linked in mammals and on the basis of its expression in many tissues, it can be regarded as a typical "housekeeping" gene (2). Over 300 variants of the protein are known, many of which have deficient enzyme activity. Nearly 100 of these variants are polymorphic in various populations (3). The mammalian enzyme is a homodimer or a homotetramer with a subunit molecular weight of approximately 56000 daltons (4). Here we report the isolation of cDNA clones from HeLa cells, SV40-transformed human fibroblasts, human placenta and human teratocarcinoma cell lines. These clones have enabled us to sequence the entire coding region of Gd. Thus, the entire amino acid sequence of human G6PD is provided for the first time. This work is the first step for structural analysis of G6PD variants and for an understanding of the biological features of this enzyme at the molecular level.

Amino Acid Sequence↗
PubMed1986

Structural analysis of the X-linked gene encoding human glucose 6-phosphate dehydrogenase.

We report the isolation and analysis of human genomic DNA clones spanning about 100 kb of the X chromosome and comprising the entire gene coding for the enzyme glucose 6-phosphate dehydrogenase (G6PD). The G6PD gene is 18 kb long and consists of 13 exons: the protein-coding region is divided into 12 segments ranging in size from 12 to 236 bp; an intron is present in the 5' untranslated region. Mature G6PD mRNA has a single polyadenylation site in HeLa cells. The major 5' end of mature G6PD mRNA in several cell lines is located 177 bp upstream of the translation initiating codon; longer mRNA molecules extending further in the 5' direction could be identified by S1 mapping and by comparing genomic and cDNA sequences. The DNA sequence around the major mRNA start is very GC rich; as to putative transcription regulatory sequences, a non-canonical TATA box and 9 CCGCCC elements are present, but no CAAT element could be identified. The genomic DNA we have isolated includes another ubiquitously transcribed region, provisionally named the GdX gene. Although the function of GdX is as yet unknown, we have established that this gene is located about 40 kb downstream of G6PD and is transcribed in the same direction. A comparative analysis of the promoter region of G6PD and 10 other housekeeping enzyme genes has confirmed the presence of a number of common features. In particular, in the eight cases in which a 'TATA' box is present, a conserved sequence of 25 bp is seen immediately downstream.

Base Sequence↗