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Biomedical subjects

L Luzzatto

Publications and source records attributed to L Luzzatto.

At least 19 recordsLinked to original sources
PubMed2004

[Breast surgery in HIV-positive women].

The increasing of HIV infection in young women as well as prolonged survival let us to register an important rising of breast cancers in such type of patients. The Authors report the case of a 48 year old HIV-positive woman, who underwent surgery because of the histological positivity for cancer of the right breast. It was decided to perform a quadrantectomy and reconstruction with implant, because of the absence of immunodepression. The Authors discuss about indications for reconstructive surgery in seropositive women with breast cancer.

Breast Neoplasms↗
PubMed2003

Prospective analysis of minimal bone marrow infiltration in pediatric Burkitt's lymphomas by long-distance polymerase chain reaction for t(8;14)(q24;q32).

The chromosomal translocation t(8;14)(q24;q32) represents a characteristic marker for Burkitt's lymphoma (BL). This translocation involves the MYC oncogene on chromosome 8 and the immunoglobulin heavy-chain (IgH) locus on chromosome 14. Since the translocation does not produce a fusion gene, we established a long-distance polymerase chain reaction (LD-PCR) assay that can detect the t(8;14) at the genomic level. The sensitivity of the LD-PCR was 10(-4). We used the LD-PCR assay to prospectively study 78 BL patients and found a specific PCR product in 52 of them. Among the 52 positive patients, we could test both the tumor and the bone marrow (BM) at diagnosis in 33 and determined the prevalence of minimal disseminated disease (MDD) at diagnosis. In 12/33 patients, BM was positive by LD-PCR and in 10 of them we conducted a study of minimal residual disease (MRD). Eight out of 10 children showed a clearance of MRD after one cycle of chemotherapy. The only two patients who did not achieve a negative MRD status died of disease progression. The comparative analysis of sensitivity of BM aspirate, BM biopsy and LD-PCR in t(8;14)-positive patients demonstrated a superiority of the molecular method in the assessment of MDD. The LD-PCR for t(8;14) is an important tool to study minimal BM infiltration at diagnosis and to determine its response kinetics in BL.

Adolescent↗
PubMed2003

[From molecular biology to new treatment approaches to colorectal cancer: basic research, experimental trials and surgical implications].

The Authors review the natural history of colorectal cancer from the point of view of molecular biology and genetics from aberrant crypts foci and familiar adenomatous polyposis to hereditary non polyposis colon cancer and sporadic colorectal cancer. They carry out international literature about basis knowledges, experimental trials and personal studies. Up to day traditional colorectal cancer surgical treatments and adjuvant or neoadjuvant pharmacological therapy cannot be modified, nevertheless "new drugs generation" known as signal transduction inhibitor could, in the future, prove to be an effective cancer treatment. The Authors highlight recent experimental clinical trials probably able to prevent sporadic colorectal cancer spreading and precursor evolution.

Adenomatous Polyposis Coli↗
PubMed2003

[Changes in the expression of cellular alpha and beta tubulins in patients with sporadic type colorectal cancer].

The aim of this preliminar report is to evaluate alfa and beta tubulins, components of cellular microtubules, alterated expression in sporadic colorectal cancer patients. The Authors considered 16 patients who underwent surgery for sporadic colorectal carcinoma with radical intent. Alfa and beta tubulins were evaluated in tumoral mucosa by immunohistochemistry. In 56.2% of the examined patients a low expression of alfa and beta tubulins was showed while the alteration of alfa tubulin was showed in 81.2% of the patients. This finding supports the hypothesis of Porter that alterations in microtubule structure might be part of the cellular response to DNA damage.

Colorectal Neoplasms↗
PubMed2003

[Telementoring in surgery].

Tele-mentoring is an interactive experimental method that allows young surgeons' education by distant learning tutoring of an expert surgeon. The problem about assessment of efficacy and quality of computer-assisted instruction is under evaluation today. Tele-mentoring is supported by videoconferencing system and it is not an exclusive methodology but an additional methodology to traditional didactic for clinicians and surgeons. It allows personal virtual trainings by computers and telecommunication systems. Videoconference allows tutoring for telemedicine, teletriage and telesurgery also.

Education, Distance↗
PubMed2002

Dynamics of hematopoiesis in paroxysmal nocturnal hemoglobinuria (PNH): no evidence for intrinsic growth advantage of PNH clones.

PNH is characterized by expansion of one or more stem cell clones with a PIG-A mutation, which causes a severe deficiency in the expression of glycosylphosphatidylinositol (GPI)-anchored proteins. There is evidence that the expansion of PIG-A mutant clones is concomitant with negative selection against PIG-A wild-type stem cells by an aplastic marrow environment. We studied 36 patients longitudinally by serial flow cytometry, and we determined the proportion of PNH red cells and granulocytes over a period of 1-6 years. We observed expansion of the PNH blood cell population(s) (at a rate of over 5% per year) in 12 out of 36 patients; in all other patients the PNH cell population either regressed or remained stable. The dynamics of the PNH cell population could not be predicted by clinical or hematologic parameters at presentation. These data indicate that in most cases the PNH cell expansion has already run its course by the time of diagnosis. In addition, since in most cases no further expansion takes place, we can infer that the tendency to overgrow normal cells is not an intrinsic property of the PNH clone.

Adolescent↗
PubMed2001

Glucose 6-phosphate dehydrogenase expression is less prone to variegation when driven by its own promoter.

The ability to transfer permanently genes into mammalian cells makes retroviruses suitable vectors for the ultimate purpose of treating inherited genetic disease. However, expression of the retrovirally transferred genes is variable (position effect and expression variegation) because retroviruses are highly susceptible to the influence of the host genome sequences which flank the integration site. We have investigated this phenomenon with respect to the human housekeeping enzyme, glucose 6-phosphate dehydrogenase (hG6PD). We have constructed retroviral vectors in which the hG6PD cDNA is driven by either of two conventional retroviral promoters and enhancers from the Moloney Murine Leukemia Virus (MMLV) and the Myeloproliferative Sarcoma Virus (MPSV) long terminal repeats (LTR) or by the hG6PD own promoter replacing most of enhancer and promoter LTR (GRU5). We have compared the activity of retrovirally transferred hG6PD driven by these promoters after retroviral integration in bulk cultures and in individual clones of murine fibroblasts. The level of hG6PD expressed by the hG6PD promoter of GRU5-G6PD was significantly lower than that expressed by conventional retroviral vectors. However, analysis of the single copy clones showed less variation of expression with GRU5-G6PD (coefficient of variation, CV, 35.5%) than with conventional vectors (CV, 58.9%). Thus we have several vectors competent for reliable transfer and expression of hG6PD. The hG6PD promoter provides reproducible expression of hG6PD and limits the variability of expression. This decreased variability is important in order to help ensuring a consistent level of delivery of the needed gene product in future therapeutic protocols.

3T3 Cells↗
PubMed2001

Human CD1d-glycolipid tetramers generated by in vitro oxidative refolding chromatography.

CD1 molecules are specialized in presenting lipids to T lymphocytes, but identification and isolation of CD1-restricted lipid specific T cells has been hampered by the lack of reliable and sensitive techniques. We here report the construction of CD1d-glycolipid tetramers from fully denatured human CD1d molecules by using the technique of oxidative refolding chromatography. We demonstrate that chaperone- and foldase-assisted refolding of denatured CD1d molecules and beta(2)-microglobulin in the presence of synthetic lipids is a rapid method for the generation of functional and specific CD1d tetramers, which unlike previously published protocols ensures isolation of CD1d tetramers loaded with a single lipid species. The use of human CD1d-alpha-galactosylceramide tetramers for ex vivo staining of peripheral blood lymphocytes and intrahepatic T cells from patients with viral liver cirrhosis allowed for the first time simultaneous analysis of frequency and specificity of natural killer T cells in human clinical samples. Application of this protocol to other members of the CD1 family will provide powerful tools to investigate lipid-specific T cell immune responses in health and in disease.

Animals↗
PubMed2001

The cellular pathogenesis of paroxysmal nocturnal haemoglobinuria.

Paroxysmal nocturnal haemoglobinuria (PNH) is a unique disorder characterised by the triad of intravascular haemolysis, thrombosis and bone marrow failure. In the early seventies it was shown that PNH is a clonal disease; and in the nineties the molecular basis of the PNH abnormality was elucidated. However, what makes a PNH clone expand is still not known. Here, we suggest that this is due to somatic cell selection, resulting from the presence in the patient of autoreactive T cells that target glycosylphosphatidylinositol (GPI) in the context of an MHC-like molecule on the surface of haemopoietic stem cells. PNH cells would escape damage precisely because they have lost most or all of their ability to produce GPI.

Hemoglobinuria, Paroxysmal↗
PubMed2001

Cytogenetic and morphological abnormalities in paroxysmal nocturnal haemoglobinuria.

Paroxysmal nocturnal haemoglobinuria (PNH) is characterized by the expansion of a haematopoietic stem cell clone with a PIG-A mutation (the PNH clone) in an environment in which normal stem cells are lost or failing: it has been hypothesized that this abnormal marrow environment provides a relative advantage to the PNH clone. In patients with PNH, generally, the karyotype of bone marrow cells has been reported to be normal, unlike in myelodysplastic syndrome (MDS), another clonal condition in which cytogenetic abnormalities are regarded as diagnostic. In a retrospective review of 46 patients with a PNH clone, we found a karyotypic abnormality in 11 (24%). Upon follow-up, the proportion of cells with abnormal karyotype decreased significantly in seven of these 11 patients. Abnormal morphological bone marrow features reminiscent of MDS were common in PNH, regardless of the karyotype. However, none of our patients developed excess blasts or leukaemia. We conclude that in patients with PNH cytogenetically abnormal clones are not necessarily malignant and may not be predictive of evolution to leukaemia.

Adolescent↗
PubMed2001

Association of clonal T-cell large granular lymphocyte disease and paroxysmal nocturnal haemoglobinuria (PNH): further evidence for a pathogenetic link between T cells, aplastic anaemia and PNH.

There is mounting evidence to suggest that T-cell-mediated suppression of haemopoiesis is a pathogenetic mechanism in three bone marrow failure syndromes: aplastic anaemia (AA), paroxysmal nocturnal haemoglobinuria (PNH) and myelodysplasia (MDS). T-cell microclones can be detected by sensitive polymerase chain reaction (PCR)-based methods in all three disorders. Recently, larger clonal populations of T-cell large granular lymphocytes (T-LGLs) have been observed in some patients with AA and MDS. Here, we report the development of a large clonal T-LGL population in a patient with bona fide PNH. In this patient, we defined part of the sequence of the T-cell receptor (TCR) beta-chain gene, and we have shown that the large T-LGL population emerged from a background of multiple smaller T-cell clones. Thus, T-LGL clones in AA, MDS and PNH probably expand as a result of antigenic stimulation. It is postulated that the antigen driving clonal T-cell proliferations in these disorders exists on haemopoietic stem cells.

Adult↗
PubMed2001

[Genetics-based prognosis evaluation of patients surgically treated for sporadic colorectal cancer].

The basic assumption as rationale of this research was that DNA repair genes (MMR system) are at beginning of the genetic mutational cascade causing the induction of oncogenesis of sporadic colorectal cancers as well as their multiclonal heterogeneity. In a previous study the Authors randomly selected, from a series of 256 patients, 29 patients up to the age of 60 years who underwent surgery for colorectal carcinoma with radical intent. All selected cases were considered as sporadic cancers from a clinical point of view, since none of them fulfilled the Amsterdam criteria for HNPCC and familial adenomatous polyposis was included too. Mismatch repair gene proteins expression and, in particular, gene hMSH2 protein was investigated by immunohistochemistry analysis. In 12 cases (41.4%) hMSH2 exhibited strong expression in the tumoral cells as well as in the surrounding mucosa and at distant mucosa. In 14 cases (48.3%) loss of hMSH2 protein expression was observed in tumoral cells and low immunoreactivity was detected in peritumoral mucosa while strong hMSH2 expression was observed in distant mucosa. In a third small group of patients (10.3%) loss of hMSH2 protein expression was detected in tumoral, adjacent and at distance normal mucosa. After a five years follow up, 100% of twelve patients of first group are still alive vs 64.3% of fourteen patients of second group, while in the third group only one patient survives. These results support the hypothesis of an involvement of hMSH2 gene defect in development of a subset of sporadic colorectal cancer. For the patients with strong expression of hMSH2 in the tumoral cells as well as in the surrounding mucosa and at distant mucosa, this parameter could represent an independent criterion for a good prognostic value.

Colorectal Neoplasms↗
PubMed2000

Stable in vivo expression of glucose-6-phosphate dehydrogenase (G6PD) and rescue of G6PD deficiency in stem cells by gene transfer.

Many mutations of the housekeeping gene encoding glucose-6-phosphate dehydrogenase (G6PD) cause G6PD deficiency in humans. Some underlie severe forms of chronic nonspherocytic hemolytic anemia (CNSHA) for which there is no definitive treatment. By using retroviral vectors pseudotyped with the vesicular stomatitis virus G glycoprotein that harbor the human G6PD (hG6PD) complementary DNA, stable and lifelong expression of hG6PD was obtained in all the hematopoietic tissues of 16 primary bone marrow transplant (BMT) recipient mice and 14 secondary BMT recipients. These findings demonstrate the integration of a functional gene in totipotent stem cells. The average total G6PD in peripheral blood cells of these transplanted mice, measured as enzyme activity, was twice that of untransplanted control mice. This allowed the inference that the amount of G6PD produced by the transduced gene must be therapeutically effective. With the same vectors both the cloning efficiency and the ability to form embryoid bodies were restored in embryonic stem cells, in which the G6PD gene had been inactivated by targeted homologous recombination, thus effectively rescuing their defective phenotype. Finally, expression of normal human G6PD in hG6PD-deficient primary hematopoietic cells and in human hematopoietic cells engrafted in nonobese diabetic/severe combined immunodeficient mice was obtained. This approach could cure severe CNSHA caused by G6PD deficiency.

3T3 Cells↗
PubMed2000

Abnormal T-cell repertoire is consistent with immune process underlying the pathogenesis of paroxysmal nocturnal hemoglobinuria.

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired clonal disorder of the hematopoietic stem cell (HSC). Somatic mutations in the PIG-A gene result in the deficiency of several glycosylphosphatidylinositol-linked proteins from the surface of blood cells. This explains intravascular hemolysis but does not explain the mechanism of bone marrow failure that is almost invariably seen in PNH. In view of the close relationship between PNH and idiopathic aplastic anemia (IAA), it has been suggested that the 2 disorders might have a similar cellular pathogenesis, namely, that autoreactive T-cell clones are targeting HSCs. In this paper, we searched for abnormally expanded T-cell clones by size analysis of the complementarity-determining region 3 (CDR3) in the beta variable chain (BV) messenger RNA (mRNA) of the T-cell receptor (TCR) in 19 patients with PNH, in 7 multitransfused patients with hemoglobinopathy. and in 11 age-matched healthy individuals. We found a significantly higher degree of skewness in the TCR BV repertoire of patients with PNH, compared with controls (R(2) values 0.82 vs 0.91, P <.001). The mean frequency of skewed families per individual was increased by more than 2-fold in patients with PNH, compared with controls (28% +/- 19.6% vs 11.4% +/- 6%, P =.002). In addition, several TCR BV families were significantly more frequently skewed in patients with PNH than in controls. These findings provide experimental support for the concept that PNH, like IAA, has an immune pathogenesis. In addition, the identification of expanded T-cell clones by CDR3 size analysis will help to investigate the effect of HSC-specific T cells on normal and PNH HSCs.

Adolescent↗
PubMed2000

Therapeutic haemoglobin synthesis in beta-thalassaemic mice expressing lentivirus-encoded human beta-globin.

The stable introduction of a functional beta-globin gene in haematopoietic stem cells could be a powerful approach to treat beta-thalassaemia and sickle-cell disease. Genetic approaches aiming to increase normal beta-globin expression in the progeny of autologous haematopoietic stem cells might circumvent the limitations and risks of allogeneic cell transplants. However, low-level expression, position effects and transcriptional silencing hampered the effectiveness of viral transduction of the human beta-globin gene when it was linked to minimal regulatory sequences. Here we show that the use of recombinant lentiviruses enables efficient transfer and faithful integration of the human beta-globin gene together with large segments of its locus control region. In long-term recipients of unselected transduced bone marrow cells, tetramers of two murine alpha-globin and two human betaA-globin molecules account for up to 13% of total haemoglobin in mature red cells of normal mice. In beta-thalassaemic heterozygous mice higher percentages are obtained (17% to 24%), which are sufficient to ameliorate anaemia and red cell morphology. Such levels should be of therapeutic benefit in patients with severe defects in haemoglobin production.

Animals↗