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Biomedical subjects

D W Ross

Publications and source records attributed to D W Ross.

At least 19 recordsLinked to original sources
PubMed1992

Epstein-Barr virus integration in human lymphomas and lymphoid cell lines.

BACKGROUND: Epstein-Barr virus (EBV) is maintained as an episome in most infected cells. The presence of fused terminal restriction enzyme fragments distinguishes the circular DNA form from the linear virion form. METHODS: EBV genomic structure was analyzed in 8 lymphoid cell lines and 21 human lymphoma specimens by the Southern blot technique. RESULTS: Evidence of viral integration into host chromosomal DNA was identified in four cell lines. In the Namalwa and BL30-B95.8 cell lines, integration occurred through the terminal repeat (TR) sequences. In the BL41-P3HR1 and BL41-B95.8 cell lines, there was loss of left-end viral genomic sequences, including ori-P sequences required for episome maintenance, implying that integration was required for viral genome persistence. Integration was not detected in four other cell lines (Raji, Daudi, B95.8, and BL30-P3HR1). In 21 EBV-containing human lymphomas, including 18 immunodeficiency-related lymphomas, fused TR sequences were identified without evidence of viral genomic integration. CONCLUSIONS: These findings suggest that, although viral integration is common in Burkitt lymphoma cell lines infected in vitro, integration is not common in human lymphomas that develop in vivo in normal or immunodeficient people.

Adolescent↗
PubMed1992

Classification and staging of lymphoma by molecular genetics.

Recombinant DNA technology has provided a wealth of new observations in the study of lymphoma. Progress has been enhanced by the unique rearrangement of immune-specific genes during normal lymphocyte differentiation. Because these gene rearrangements are irreversible and are inherited in all cellular progeny, lymphoid tumors have a monoclonal genomic structure. Molecular analysis of genomic structure is a powerful new method of assessing clonality and lineage to supplement histologic examination in achieving accurate diagnosis and staging of lymphomas. Furthermore, the frequent occurrence of translocations in lymphoid neoplasms provides a second pathway for genomic analysis. In 57 B-cell lymphomas tested by Southern blot and polymerase chain reaction, the authors found evidence of bc12 gene translocation in 100% of follicular small cleaved cell lymphomas, 67% of diffuse small cleaved cell lymphomas, 33% of mixed lymphomas, 25% of diffuse large cell lymphomas, and 25% of small noncleaved lymphomas. They also describe their experience with immunoglobulin heavy chain and T-cell receptor beta chain genomic analysis as well as review the published literature on the utility of molecular genetics in the classification and staging of lymphoma. Future applications of molecular diagnostics in the clinical management of lymphoma patients are assessed.

Base Sequence↗
PubMed1991

An inventory of the personal computers for students' use at 143 U.S. and Canadian medical schools.

The National Board of Medical Examiners (NBME) has been developing new tests to be administered using computers. As these tests near readiness for use, logistical issues of test administration have become important. In 1989-1990, in order to plan for the implementation of computer-based testing in NBME examinations of the future, the authors, under the auspices of the NBME, conducted a telephone survey of knowledgeable individuals at the 143 LCME-accredited medical schools in the United States and Canada to gauge the numbers and types of microcomputers and workstations available for students' use at these schools. The findings, based on the responses of all the schools surveyed, are reported.

Canada↗
PubMed1991

Systemic idiopathic fibrosis with T-cell receptor gene rearrangement.

A case of systemic idiopathic fibrosis was analyzed by Southern blotting with probes to the immunoglobulin heavy chain and T-cell receptor genes. A 45-year-old man presented with bilateral neck swelling. He later developed lower back pain, and findings on a computed tomographic scan were consistent with idiopathic retroperitoneal fibrosis. A biopsy specimen of a neck lesion showed morphologic characteristics typical of idiopathic fibrosing cervicitis. Immunophenotyping of the lesion revealed a polymorphic lymphoid population. Molecular analysis with the use of probes to the immunoglobulin and T-cell receptor genes disclosed a germline DNA pattern for the immunoglobulin gene and a rearranged pattern for the T-cell receptor gene.

Antibodies, Monoclonal↗
PubMed1991

Mitochondrial Eve.

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DNA, Mitochondrial↗
PubMed1990

Neutrophil myeloperoxidase measurement uncovers masked megaloblastic anemia.

We report the observation of a high neutrophil myeloperoxidase activity (MPXI) in patients with megaloblastic anemia. MPXI is rapidly measured as part of an automated complete blood count (Technicon H*1, Technicon Instruments Corp, Tarrytown NY). We describe the range of MPXI levels in healthy and patient populations and in 10 cases of megaloblastic anemia, including five having elevated mean cell volume (MCV) and five without macrocytosis. Regardless of the MCV, our megaloblastic patients had hypersegmented neutrophils and elevated MPXI levels without visible alteration of granule content. MPXI measurement may be particularly useful in identifying cases of "masked megaloblastic anemia" where the MCV is below 100 fL. The advantage of the MPXI over other methods of uncovering masked megaloblastic anemia is its simplicity when performed as part of a routine complete blood count on an automated hematology instrument.

Adolescent↗
PubMed1990

Pathology.

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Pathology↗
PubMed1990

Whole blood staining in suspension for nonspecific esterase and alkaline phosphatase analyzed with a Technicon H-1.

We adapted previously published methods for nonspecific esterase and alkaline phosphatase staining of white blood cells in suspension for use on a Technicon H-1 hematology analyzer. The objective was to develop a semiautomated method using whole blood that could be employed on a large scale for hematology laboratory applications, including toxicology studies, measurement of neutrophil left shift, and cytochemical classification of myeloid leukemias. The nonspecific esterase method uses the pararosaniline stain, generating the unstable substrate from two stable precursors. Whole blood is added to the substrate plus dye mix. Next, acid lysis and fixation steps destroy red cells and stabilize the monocyte staining. The alkaline phosphatase stain employs a stable naphthyl phosphate substrate and fast blue B coupling dye. The red cells are lysed with a pH 10.3 propanediol buffer, and the white blood cells are then stabilized with formalin fixation. For both methods the staining is performed off-line, and the sample is then diluted with propanediol to match the refractive index of the sheath on the H-1 analyzer, before aspiration into the direct cytometry port. A cytogram of scattered versus absorbed light is obtained. The number of cells staining and the intensity of the stain can be quantified from the cytogram.

Alkaline Phosphatase↗
PubMed1990

Bcr/abl recombinant DNA analysis versus karyotype in the diagnosis and therapeutic monitoring of chronic myeloid leukemia.

Karyotype and bcr/abl recombinant DNA analyses are two means of detecting the chromosomal aberration in chronic myeloid leukemia. The authors compared these two methods in a retrospective study of 36 patients with CML in which they found the bcr/abl DNA recombinant event in 100% (29 of 29) of those patients who had the Philadelphia chromosome. To achieve this sensitivity, a battery of two bcr probes and three restriction enzymes is necessary. The authors propose a sequential algorithm for efficient use of these probes and enzymes. In 76% of the patients, bcr/abl rearrangement can be detected with a Bgl II digest and a 3' commercial probe. An additional 21% of patients can be detected by a second assay in which the same membrane is rehybridized to a 3' and 5' combination bcr probe. One patient (3%) required an additional restriction enzyme digest with BamH I to detect the recombinant event by the same 3' probe. Karyotype analysis is used to determine cytogenetic remission in patients with CML under therapy. The authors studied the use of DNA analysis by the Southern blot technique to detect a decrease in the relative number of leukemic cells. By dilution studies and densitometric scanning of autoradiographs, the authors were able to detect a 15% decrease in the relative number of cells having the bcr/abl recombinant event. The authors report the preliminary results of three patients in whom they compared the karyotype and recombinant DNA analysis at multiple time points in their clinical course. In conclusion, the bcr/abl recombinant DNA analysis is superior to karyotype for the diagnosis of CML and can be used for monitoring treated patients.

Adolescent↗
PubMed1990

Restriction enzymes.

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DNA Restriction Enzymes↗