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Biomedical subjects

B H Hyun

Publications and source records attributed to B H Hyun.

At least 55 records · Page 3Linked to original sources

Rapid determination of in vivo and in vitro antibody responses by suspension hemolytic assay.

A suspension hemolytic (SH) assay newly modified in this laboratory was applied to the measurement of primary IgM antibody responses, such as T-dependent, T-independent, and polyclonal B cell responses in in vivo and in vitro assays. All results of the SH assay were equal to those of the conventional plaque-forming cell (PFC) assay. With the SH assay in in vitro assays, we could separately measure the amount of the IgM that had been produced during the whole immunization period and measure the IgM newly produced during the shorter time of the assay. The immunomodulations by dioxin and glycopeptide were accurately evaluated by the SH and the PFC assay. Our study suggested that the SH assay modified in this laboratory was more advantageous because of the simplicity of the assay and better analysis of data than the PFC assay, and could be used as the primary method in studying the effects of pharmaceutical and toxic agents on humoral immune functions.

Animals↗

Selective suppression of in vitro T-dependent humoral immunity by synthetic food additive antioxidants.

Effect of antioxidants on humoral immune responses, such as butylated hydroxytoluene (BHT), n-propyl gallate (PG) and dimethyl sulfoxide (DMSO) is suppression in vitro antibody production. These antioxidants all inhibited T-dependent B cell response, not T-independent and polyclonal B cell response. These data suggest that antioxidants suppress humoral immunity by suppression of regulation of T cells or action of macrophages on B cells, not by direct suppression of B cells. The other possible explanation for antioxidant action is the lack of T-B cell contact required for the triggering of the B cell response with T-dependent antigens.

Animals↗

Functional human hepatocytes: isolation from small liver biopsy samples and primary cultivation with liver-specific functions.

Morphologically and functionally intact human hepatocytes were isolated from small liver biopsy samples weighing about 1-2 g by initial digestion with collagenase followed by repeated digestions with trypsin. The usual yield of hepatocytes was greater than 1 x 10(7) cells per g of liver sample and cell viability, as judged by dye exclusion test, was routinely over 90%. The isolated human hepatocytes showed intact morphology under scanning electron microscope. Formation of membrane protrusions upon phalloidin addition demonstrated that the actin in isolated hepatocytes was maintained with its structural integrity. The cultured human hepatocytes retained a variety of liver-specific functions which were similarly exhibited by rat hepatocytes isolated using the same procedure. The cultured human hepatocytes exhibited a specific cytochrome P-450 related enzyme activity, and active amino acid uptake that increased upon addition of hormones like glucagon and dexamethasone. Additionally, the cultured human hepatocytes synthesized DNA actively and, human serum albumin, and was found to be responsive to modulation by growth modulating hormones, cytokines and hepatotoxic agents. Based on the profile of activity described above, the presently established conditions for isolation and culturing of human hepatocytes demonstrate that functional liver cells can be obtained from small biopsied liver samples.

Albumins↗

Blood smear examination.

Despite recent advances in the automation of clinical hematology laboratories, a careful microscopic examination of an appropriately prepared and stained blood smear continues to maintain its status as the most informative and useful diagnostic procedure, and offers a simple, reliable means of verifying results generated by automated analyzers. A systematic approach to a comprehensive evaluation of blood cells and related findings is described.

Blood Cell Count↗

Fundamentals of bone marrow examination.

Bone marrow evaluation is an important and effective way of diagnosing and evaluating primary hematologic and metastatic neoplasms as well as nonhematologic disorders. Many variations exist for obtaining marrow samples (sites, instruments, techniques); however, the method outlined in this article has proven reliable. Complete evaluation of bone marrow samples should include a brief patient history, pertinent laboratory data, peripheral blood films, bone marrow aspirate smears and sections, and biopsy imprints and sections. Routine examination of the bone marrow as described previously is usually adequate for interpretation. However, application of additional studies using cytochemical, immunocytochemical, immunohistochemical, cytogenetic, and molecular techniques may prove to be of critical importance in the diagnosis of hematologic malignancies.

Biopsy, Needle↗

The automated CBC. A current perspective.

CBC traditionally stands for complete blood count. It represents a profile of tests rather than a single test, and over the years it has been given several names, including hemogram, Coulter profile, blood cell profile, and hematology profile. The number and type of tests included in the profile has also changed over time and among laboratories, depending primarily upon capabilities of the automated analyzers used to perform the profile test.

Autoanalysis↗

Immunohistochemical evaluation of hematologic malignancies.

This article summarizes the most recent developments and current practice of immunohistochemistry in the diagnosis of hematologic malignancy. Increased availability of monoclonal antibodies applicable in formaldehyde-fixed and paraffin-embedded tissue is discussed as are immunohistochemical definitions for many small cell lymphoma entities. Evaluation is made of the biologic potential of lymphomas and leukemias by the use of antibodies to proliferation antigens, such as Ki-67 and products of tumor suppressor genes (p53).

B-Lymphocytes↗

Multiple myeloma and chronic myelogenous leukemia--a case report with literature review.

This is the case of a 71 year old male who developed multiple myeloma (MM) and chronic myelogenous leukemia (CML) within a two year period. The patient initially presented with osteolytic lesions of the lumbar spine, and following the initial work-up a diagnosis of multiple myeloma with an IgG kappa paraproteinemia was made and appropriate treatment was given. Two years later the patient developed a progressively worsening leukocytosis which was found to be due to Philadelphia Chromosome (Ph1) positive CML. The occurrence in the same patient of two distinct hematologic malignancies suggests a neoplastic transformation of a pluripotent stem cell. A review of the literature appears to support the existence of a relationship between MM and CML as well as a relationship between MM and the myeloproliferative disorders.

Aged↗

Advances of the past decade in automated hematology.

During the decade of the 1980s, a wealth of information accumulated concerning automation in hematology. Recent technological advances led the way to the development of blood cell analyzers capable of performing a ten-parameter (or greater) complete blood count and five-parameter (or greater) differential leukocyte count on a small amount of whole blood and in an accurate, efficient, and economical way. The authors summarize the available information concerning the data generated by these analyzers, the mechanisms involved in the data generation, and the clinical applications and usefulness or limitations of the so-called new complete blood count parameters and of the automated differential as it compares with the manual differential.

Automation↗

Differential leukocyte count: manual or automated, what should it be?

Today's automated hematology analyzers capable of performing a full CBC and a differential leukocyte count (DLC) on whole blood, particularly in a closed tube system, using cytochemistry or impedance-based flow cytometry technology coupled with laser light scattering, conductivity and/or differential cell lysis, are here to stay. Their need and popularity among at least the large, cost and quality-conscious clinical laboratories have been growing for the past few years and will continue to do so in the years ahead. The efficiency and reliability of several of these analyzers in performing complete CBCD (CBC and DLC) and in flagging significant abnormalities have been tested and found acceptable with the need to review a stained blood smear or perform a manual DLC to confirm or obtain additional information on selected cases.

Automation↗

A new mouse strain manifesting high proteinuria and kidney glomerular defect.

A mutant strain of mice manifesting high proteinuria, wasting syndrome, and kidney glomerular defect was established from the F5 offspring of an interstrain cross of CBA/Nga and RFM/Nga mice. Affected mice had high levels of proteinuria after 40 days of age. The body weight of about 22.6% of affected mice decreased rapidly and they died between 3 and 5 months of age. We learned that this abnormality is controlled by two pairs of autosomal recessive genes; the mutant strain of mice is designated FGS/Nga. The mutant strain has been characterized by high proteinuria and renal lesions with focal sclerosis of glomeruli and tubular atrophy with interstitial nephritis in the kidney resembling the human disease. The FGS/Nga mouse strain is a potential animal model for studying kidney glomerular defect in humans.

Animals↗

Myeloproliferative disorders. Classification and diagnostic features with special emphasis on chronic myelogenous leukemia and agnogenic myeloid metaplasia.

Leukocytosis, mild anemia, thrombocytosis, and panhyperplasia in the marrow characterize the early stages of most of the CMPD, whereas extramedullary hematopoiesis (such as in the spleen or liver), peripheral cytopenias (anemia, leukopenia, or thrombocytopenia), and myelofibrosis, with or without osteosclerosis, reflect the changes seen in the later stages. Transitions among the different CMPD and termination in acute leukemia or marrow failure also are common. CML often is characterized by leukocytosis and the presence of the entire spectrum of granulocytes (mature and immature) in the blood and marrow, reduced LAP, hypercellularity with prominent granulocytic hyperplasia in the marrow, Ph chromosome, and bcr-abl gene rearrangement. Typical features of AMM include leukoerythroblastosis, teardrop poikilocytosis, anemia, increased or normal LAP, prominent megakaryocytic hyperplasia in the marrow, dyshematopoiesis, and hyperplastic or fibrotic/sclerotic marrow.

Chromosome Aberrations↗

Structure and function of the bone marrow and hematopoiesis.

Bone marrow, a well-organized tissue located within the bone cavities, is richly innervated and highly vascularized but devoid of lymphatics. Structurally, it consists of two major cellular elements, the stromal cells (reticular cells--fibroblasts, endothelial cells, adipocytes, and so on) and the parenchymal cells (hematopoietic cells). Functionally, it serves as the primary site for hematopoiesis and as a major reticuloendothelial organ involved in immune responses (cellular and humoral) and removal of senescent and abnormal cells and particulate material. An uncommitted pluripotential hematopoietic stem cell, itself a product of the differentiation of mesenchymal cells of the yolk sac and capable of self-replication, undergoes proliferation and differentiation in an orderly manner, generating immature committed progenitors with uni-, bi-, or trilineage specificity. These committed progenitors also multiply and differentiate in a sequential fashion, ultimately producing mature cells that are released into the circulation. Under steady state conditions, the cell death/loss is balanced by cell production by virtue of regulatory mechanisms that apparently involve (1) cell-cell interaction between marrow cells and (2) production of humoral growth and/or inhibitory factors by stromal and parenchymal cells individually or in concert. Some of these regulators of hematopoiesis have been isolated, purified, molecularly cloned, and characterized. The availability of recombinant growth factors has stimulated clinical trials of these factors as therapeutic agents.

Bone Marrow↗

Bone marrow examination: techniques and interpretation.

Proper evaluation of the bone marrow requires adequate sampling, appropriate specimen processing, sufficient clinical history, and review of representative blood smears and pertinent laboratory data. Aspiration and needle biopsy should be performed at the same time routinely. Aspirate smears, touch preparations from the biopsy, and sections from the aspirate and biopsy should be processed appropriately and examined in a systematic fashion to perform a comprehensive evaluation considered essential to arrive at or rule out a diagnosis, or as an adjunct in the management of patients, particularly those undergoing chemotherapy and/or radiotherapy.

Biopsy, Needle↗

Quality control in hematology.

A quality control (QC) protocol for hematology, as for other sections of the laboratory, should encompass both internal and external QC programs. The extent to which a hematology laboratory should be involved depends upon various factors, including availability of facilities, financial resources, range of tests, workload, the number of staff and their levels of training, and the overall organization of the laboratory. To ensure quality patient care, the intralaboratory QC program must include at least the minimal measures of monitoring and control at each step from collection of blood specimens, through the actual processing and analysis, to reporting of the results. The protocol should be written concisely and in simple language; the procedure manual should offer all of the pertinent information along with references; all concerned personnel should be well trained and competent; and adequate facilities and time should be available for the purpose of QC. Continuing education is also an integral part of an effective QC program. Three very important aspects of QC in hematology are calibration of automated instruments, monitoring of accuracy and precision of instruments and procedures, and verifying the reliability of test results. In the absence of a true primary reference/standard for calibration of instruments for the CBC, the most commonly performed hematologic test, the use of commercial calibrators is acceptable. A combination of commercial controls (three levels) and retained or fresh patient blood specimens is recommended for monitoring of accuracy and precision on a long- and short-term basis. Patient red-cell indices moving average data allow continuous monitoring of instrument performance and should be used as an adjunct to other QC approaches to detecting instrument calibration drift. Correlation of results of related parameters and careful review of blood films remain the two most important and widely used approaches to ensure reliability of results obtained from automated hematology instruments. Participation in an external QC program offers the most practical means of monitoring overall work performance in comparison with instrument, method, and/or reagent-based peer group data. A laboratory may choose to participate in one or more national and/or regional QC programs, depending upon the range of tests it performs and the requirements of accreditation and regulatory agencies. Most of the accreditation agencies require participation in programs covering at least all of the routinely or frequently performed tests and, if available, also in those for infrequently performed tests.(ABSTRACT TRUNCATED AT 400 WORDS)

Hematologic Tests↗

Epithelioid granulomas of the bone marrow in non-Hodgkin's lymphoproliferative malignancies.

Ten cases of epithelioid granulomas in the bone marrow of patients with various non-Hodgkin's lymphoproliferative malignancies have been encountered. These included six with non-Hodgkin's lymphoma (three histiocytic and three poorly differentiated lymphocytic types), three with multiple myeloma, and one with acute lymphoblastic leukemia. The bone marrow was not involved by the primary disease in two of the six patients with lymphoma, whereas three with lymphoma showed both granulomatous and lymphomatous lesions in the same marrow specimens, and in one, these lesions were seen in the marrow at different times. The three myeloma patients showed evidence of both myeloma and granulomas in their marrow. In the case of acute lymphoblastic leukemia, the bone marrow showed only granulomas, the leukemic process being in complete remission. Although small numbers of similar cases have been reported before, the authors were unable to find a previous report of acute lymphoblastic leukemia associated with bone marrow granulomas. Although the pathogenesis and the clinical significance of the granulomatous lesion of the bone marrow in non-Hodgkin's lymphoproliferative malignancies are unknown, this lesion should be differentiated from infectious or lipid granulomas as well as from involvement by the primary disease.

Adult↗