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M Negrini

Publications and source records attributed to M Negrini.

97 records · Page 6Linked to original sources
PubMed1983

Episomal DNA of a BK virus variant in a human insulinoma.

BK virus (BKV) DNA was detected by blot hybridization in a human adenoma of pancreatic islets from patient I.R. BKV DNA was free, and no evidence was found of viral sequences integrated into cellular DNA. Virus was rescued by transfection of human embryonic fibroblasts with tumor DNA. The DNA from rescued virus (BKV-IR) was different from wild-type BKV DNA by restriction endonuclease mapping. The genome of BKV-IR is 235 base pairs (bp) shorter than the genome of wild-type BKV. This alteration originates from a deletion of approximately 300 bp involving HindIII fragments B and D, and an insertion of 70 bp in the region of HindIII fragment C. Transformation of hamster kidney cells was induced by total tumor DNA as well as by BKV-IR and BKV-IR DNA. No antibodies to BKV tumor (T) antigen were detected in the patient's serum by immunofluorescence. The significance of episomal BKV DNA in a human tumor is discussed.

Adenoma, Islet Cell↗
PubMed1983

Formation of oligomeric free BK virus DNA is required for tandem integration of viral genomes into cellular DNA.

Mouse kidney cells have been transformed by linear BK virus (BKV) DNA with cohesive ends. These BKV genomes can circularize and subsequently replicate or physically join end to end yielding oligomeric viral DNA molecules. Blot hybridization analysis of transformed cells showed the presence of BKV DNA both in free circular forms and integrated into cellular DNA in a tandem head-to-tail array of full-length viral genomes. Formation of oligomers either by replication via previous circularization or by end to end joining is hindered after elimination of cohesive termini by digestion with the single-strand-specific nuclease S1. After treatment of linear BKV DNA with nuclease S1 only integrations of single viral genomes were observed in transformed cells; tandem insertions and free viral DNA were absent. These results support the hypothesis that formation of tandems of free viral DNA is a necessary prerequisite for tandem integration of viral genomes.

Animals↗
PubMed1982

Oncogenity of BK virus for immunosuppressed hamsters.

Tumors were induced by BK virus (BKV) inoculated intravenously in 3-week-old Syrian golden hamsters immunosuppressed with anti-lymphocyte serum or methylprednisolone acetate alone or in association with gamma-radiation (60Co). The induced neoplasms were ependymoma, carcinoma of pancreatic islets, lymphoma, osteosarcoma, undifferentiated sarcoma, kidney and renal pelvis carcinoma, pheochromocytoma and hemangiosarcoma. High levels of insulin and glucagon and altered concentrations of glucose were detected in blood of animals with tumors of pancreatic islets. No antibodies to BKV tumor antigen (TAg) and low levels of hemagglutination-inhibition antibodies to BKV viral coat protein Ag were detected in hamster sera. BKV TAg was found in tumors by complement fixation. Blot hybridization analysis of tumor DNA showed the presence of both free and integrated BKV genomes in tumor cells. BKV DNA inoculated intravenously and subcutaneously in immunosuppressed or immunocompetent hamsters was not oncogenic, whereas it was weakly oncogenic when inoculated intracerebrally.

Animals↗
PubMedDate not supplied

Lineage switch and multilineage involvement in two cases of pH chromosome-positive acute leukemia: evidence for a stem cell disease.

Philadelphia chromosome-positive acute leukemias (Ph+ AL) show variable cytologic features, possibly reflecting heterogeneous stem cell involvement. Morphologic, immunologic and cytogenetic studies were performed in two cases of Ph+ acute lymphoblastic leukemia (ALL) in order to better delineate the clinicobiological features of this cytogenetic subset of AL. Sequential cytoimmunologic studies in patient 1 documented a lineage switch from pro-B ALL with a minor myeloid component at diagnosis to minimally differentiated acute myeloid leukemia (AML) at relapse. In this patient the major breakpoint cluster region (M-bcr) was in a rearranged configuration and all metaphase cells showed t(9;22)(q34;q11), both at diagnosis and at relapse. In patient 2 a diagnosis of Ph+ early T-cell ALL with minor myeloid component was made. In this patient the M-bcr was in a germline configuration. Cytogenetic studies documented the presence of the Ph chromosome in all metaphases from a lymphoid cell population obtained by fine-needle aspiration of an enlarged lymph node, and from a bone marrow cell fraction enriched in granulocyte precursors. This finding suggests multilineage involvement in this patient. Lineage switch and multilineage involvement in two patients suggest that a pluripotent stem cell may be affected rather frequently in patients with Ph+ AL. These findings show that biologically Ph+ AL may resemble chronic myelogenous leukemia blast crisis, since it may originate from an undifferentiated stem cell carrying the t(9;22) translocation.

Acute Disease↗
PubMedDate not supplied

[Chest pain similar to angina. Identification of patients at risk of developing acute coronary failure].

In order to improve the diagnostic procedure for patients with chest pain suspected of having acute ischemic heart disease we elaborated a mathematical model to predict ischemic risk and then compared its predictive capacity with that of the physician. From September 1989 to December 1992, 564 patients with a chief symptom of chest pain were seen at our Emergency Room (ER). Sixty-two percent of them were male, mean age was 58 +/- 13 years, and none had acute myocardial infarction or unstable angina. Clinical and historical data, serial sampling of enzymes and ECG patterns were collected for 4 hours after admission to the ER. At that point a decision was made to hospitalize or discharge that patient. Follow-up was completed within 2 months. At the end of follow-up, we observed that the physician's assessment resulted in 35% true positive, 55% true negative, 4.7% false positive, and 5.3% false negative judgments for acute ischemic heart disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMedDate not supplied

Refined subchromosomal location of 21 expressed sequence tags from unknown genes at region 11p15.

Twenty-one expressed sequence tags (ESTs) belonging to unidentified transcripts were mapped to 9 intervals at 11p 15.5-p15.3. Thirteen were mapped to a region of an estimated size of 7 Mb with the help of a YAC contig. The remaining eight were mapped outside this region, and the centromeric or telomeric position of the ESTs relative to the YAC contig was defined with the help of a cellular hybrid containing a derivative chromosome 11 with a break-point within the region covered by the contig. The average size of the intervals, where the ESTs were mapped, was estimated to be 0.3-0.4 Mb. The refinement of the chromosomal location of these ESTs could be of great help in the identification of potential candidate genes for disease locus mapping at 11p15.

Animals↗