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Biomedical subjects

W C Chan

Publications and source records attributed to W C Chan.

At least 181 records · Page 10Linked to original sources
PubMed1985

Primary lymph node pathology in AIDS and AIDS-related lymphadenopathy.

Lymph nodes of patients symptomatically infected with the acquired immunodeficiency syndrome (AIDS) virus show a spectrum of morphologic changes ranging from marked lymphoid hyperplasia to marked lymphocytic depletion. These changes can be grouped into three distinct patterns. The type I pattern features follicular and paracortical hyperplasia, and is associated with chronic lymphadenopathy. The type II pattern, which shows diffuse lymphoid hyperplasia but loss of germinal centers, signifies evolution of chronic lymphadenopathy to AIDS. The type III pattern shows marked lymphocytic depletion and represents the end-stage lymph node seen in fatal AIDS. These histologic patterns are closely correlated with the clinical and immunologic status of patients infected with the AIDS virus.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Lymphocyte subsets in lymph nodes of homosexual men with generalized unexplained lymphadenopathy. Correlation with morphology and blood changes.

Frozen sections of lymph nodes from 20 homosexual men with chronic generalized lymphadenopathy and of lymph nodes showing follicular hyperplasia from 14 patients without known risk factors of the acquired immunodeficiency syndrome were studied with monoclonal antibodies to T-cell subsets and to the HLA-DR antigen. In T-cell areas of the lymph nodes, excluding tertiary paracortical nodules, the mean T-helper-to-T-suppressor ratio (Th/Ts) +/- 1 SEM was significantly lower in the homosexual group (1.07 +/- 0.06) when compared with the control group (2.49 +/- 0.23), P less than .0001. In seven homosexual men, cell suspensions from the same lymph nodes were analyzed using a fluorescence-activated cell sorter. Results obtained by this method and by immunohistochemistry were comparable except in a homosexual man whose lymph node contained large tertiary paracortical nodules. Although the Th/Ts ratios of the blood and lymph nodes of the same patients were both low, there was not good correlation between the two sets of values (r = .2). Furthermore, there was not good correlation between blood lymphocyte count and lymph node Th/Ts ratios (r = .45). The lymph node Th/Ts ratios of the homosexual patients show less variations compared with the control group. The patient who subsequently developed multiple opportunistic infections had the lowest value. Whether the lymph node Th/Ts ratio has prognostic significance in patients with the lymphadenopathy syndrome warrants further investigation.

Adolescent↗
PubMed1985

Studies on the use of nonhuman primates to determine the DR status of the human hematopoietic stem cell.

Monoclonal antibodies that recognize monomorphic determinants of human DR are potentially useful for the in vitro elimination of malignant cells from marrow for use in autologous transplantation. While DR is expressed on normal hematopoietic progenitor cells and the cells of the majority of the hematologic and lymphoid malignancies, there is the possibility that DR may not be expressed on the hematopoietic stem cells responsible for marrow regeneration after transplantation. To resolve the uncertainty regarding the DR status of the human stem cell, we determined whether antihuman DR monoclonal antibodies recognized analogous antigens on nonhuman primate hematopoietic progenitor cells to determine an appropriate animal transplant model. We used antihuman DR plus C'-mediated lysis of marrow progenitor cells as an indicator of whether the analogous nonhuman primate cells express similar antigens. Using two potent C'-fixing anti-DR monoclonal antibodies separately (5F3, AMG-12), human progenitor cells are reduced by 90%-100%. The range of progenitor cell depletion varied more widely with the nonhuman primates studied: 80%-99% with cells from the chimpanzee, 48%-100% with cells from the orangutan, and 62%-100% with cells from the rhesus monkey. Despite this, the majority of animals yielded results identical to that seen with human cells. We concluded that autologous transplantation with DR-depleted rhesus bone marrow into a lethally irradiated animal would be a practical and expeditious means to determine the DR status of the cell responsible for marrow regeneration, and by inference the DR status of the human hematopoietic stem cell.

Adult↗
PubMed1985

Primary lymphoma of the central nervous system diagnosed by computed tomographic scan-directed needle biopsy with a frozen section immunoperoxidase technique.

Primary lymphoma of the central nervous system is an uncommon neoplasm that requires definitive diagnosis because it is potentially treatable. We report a case in which the diagnosis of lymphoma was unsuspected and was made by needle biopsy with computed tomographic scan direction. A frozen section immunoperoxidase technique demonstrated monoclonality. When combined with a compatible morphological appearance, this confirmed the diagnosis of lymphoma. This case demonstrates the importance of this immunochemical method in the rapid diagnosis of central nervous system lymphomas.

Adult↗
PubMed1984

Myeloproliferative disorder with profound hypereosinophilia associated with chemotherapy for breast cancer.

A 47-year-old woman developed a unique myeloproliferative disorder 36 months after receiving adjuvant chemotherapy postoperatively for breast carcinoma. Her bone marrow and peripheral blood exhibited many of the myelodysplastic changes commonly observed in treatment-linked leukemia. In addition, there was striking marrow and blood eosinophilia and eosinophilic infiltration in multiple organs. She also developed a poorly differentiated lymphocytic lymphoma which responded to therapy. Her myeloproliferative disorder, with marked eosinophilia, continued to progress, however, and she died shortly after its diagnosis.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1984

Giant lymph node hyperplasia with unusual clinicopathologic features.

This report describes two cases of giant lymph node hyperplasia (GLNH) with unusual clinicopathologic features, both studied with immunohistochemical techniques. In the first case, mesenteric GLNH was associated with amyloidosis and the nephrotic syndrome. In the second, GLNH developed in a patient with previously treated Hodgkin's disease. In both cases, the GLNH was of the plasma cell variant. The plasma cells of the first case contained both kappa and lambda light chains, while those in the second case contained only the lambda light chain. The presence or absence of monoclonality was not predictable from the morphology alone. Cases of GLNH with unusual clinicopathologic features are reviewed and the significance of immunohistochemical studies discussed.

Adolescent↗
PubMed1984

T-cell imbalance in neutropenia of uncertain etiology.

The authors studied 16 consecutive patients with chronic neutropenia of uncertain etiology in whom bone marrow biopsies were performed. Using monoclonal antibodies, they measured the levels of the two major subclasses of T lymphocytes, cells with the T-suppressor/cytotoxic cell phenotype (Ts), and cells with the T helper/inducer cell phenotype (Th) in the blood of eight of these patients. Five patients had Ts lymphocytosis or increased proportions of Ts cells and Th lymphocytopenia. All five patients had greatly increased proportions of large lymphocytes with prominent cytoplasmic azurophilic granules. Since cells with similar morphology from normal individuals have been shown to express cytotoxic activities, the authors measured the cytotoxic function of cells from three of the patients with Ts lymphocytosis. All three possessed antibody-dependent cell-mediated cytotoxicity (ADCC) but not natural killer (NK) cell activity. Many patients had evidence of autoimmune disorders, conditions in which Ts cells usually are decreased. None had hypogammaglobulinemia, a disorder that has been associated with increased Ts activity. The high incidence of an imbalance in T lymphocyte subpopulations in patients with neutropenia suggests that disturbed immunoregulation involving T cells may play an important role in the pathogenesis of this disorder.

Adult↗
PubMed1984

Thymoma: an immunohistochemical study.

Four thymomas, two from patients with myasthenia gravis, were studied using a panel of monoclonal antibodies. Almost all the associated lymphocytes were T-cells with the common thymic lymphocyte phenotype, suggesting that the neoplastic epithelium can provide a microenvironment that retains or perhaps attracts immature T-cells. HLA-Dr antigens were expressed by some of the epithelial cells and many of the lymphoid cells in the perivascular space. The Leu-7 antigen was present on a subset of epithelial cells and had a highly variable expression in different thymomas. The percentage of lymphocytes bearing the OKT8-defined antigen appeared to be lower in patients with myasthenia gravis, while the expression of other markers did not appear to be consistently or significantly different. There did not appear to be marked differences in the lymphocyte subpopulations of thymomas with different morphology, and there was no evidence of differentiation of the thymomas into cortical and medullary areas.

Adult↗
PubMed1984

A morphologic and immunologic study of the large granular lymphocyte in neutropenia with T lymphocytosis.

We report four patients with expansion of a unique population of lymphocytes that is consistently associated with neutropenia. Two patients also had rheumatoid arthritis and autoantibodies. The lymphocytes contained many cytoplasmic azurophilic granules, which possessed strong acid phosphatase activity. Multiple cytoplasmic parallel tubular arrays were observed ultrastructurally. These granular lymphocytes showed the T suppressor/cytotoxic cell phenotype (E+, OKT3+, OKT8+, OKT4-, OKM1-, OKI1-) and exhibited antibody-dependent cell-mediated cytotoxic activity but little or no natural killer cytotoxicity. They did not respond to recall antigens, concanavalin A, or pokeweed mitogen, but the cells from one patient did respond to phytohemagglutinin. No in vitro suppressor cell activity on mitogenic responses of allogeneic cells and on mixed lymphocyte cultures could be demonstrated. There was no evidence of suppression of immunoglobulin synthesis in vivo. It is uncertain that the expansion of this subset of lymphocytes represents a leukemic process. Their constant association with neutropenia, however, raises the possibility that the increase in large granular lymphocytes and neutropenia might be pathogenetically related.

Adult↗
PubMed1984

Zinc deficiency and the development of esophageal and forestomach tumors in Sprague-Dawley rats fed precursors of N-nitroso-N-benzylmethylamine.

Nine-week-old zinc-sufficient (100 mg zinc/kg feed) and zinc-deficient (7 mg zinc/kg feed) noninbred male Sprague-Dawley rats were given free access 5 days a week to deionized drinking water containing low (0.05%) or high (0.25%) quantities of benzylmethylamine (BMA) and concurrently 0.5% NaNO2. In contrast to the action of the preformed carcinogen N-nitroso-N-benzylmethylamine, which almost invariably produced esophageal tumors, oral administration of its precursors, BMA and NaNO2, resulted in forestomach tumors as well. In both the high- and low-BMA groups given precursors for 16 weeks, the incidence of papillomas in both the esophagus and forestomach was significantly higher in the zinc-deficient than in the zinc-sufficient rats, but zinc deficiency did not significantly increase the yield of forestomach carcinomas. However, when combined high BMA and NaNO2 administration was prolonged to 37 weeks, the yield of forestomach carcinomas was significantly greater in the zinc-deficient than in the zinc-sufficient animals. Because endogenous synthesis of N-nitrosamines from ingested precursors is an important source of human exposure to these carcinogenic compounds and because dietary zinc deficiency might be operating in some areas with a high incidence of esophageal cancer, our data are of more than routine significance.

Animals↗
PubMed1983

Value of lymph node biopsy in unexplained lymphadenopathy in homosexual men.

The acquired immune deficiency syndrome (AIDS) manifested by severe opportunistic infections, Kaposi's sarcoma, or lymphoma often has a prodrome of lymphadenopathy accompanied by constitutional symptoms. We studied the histopathologic findings of lymph node biopsy specimens and peripheral blood immunologic parameters of 24 clinically indistinguishable homosexual men with chronic generalized lymphadenopathy. Two different morphological patterns were observed: (1) lymph nodes with follicular and paracortical hyperplasia in 21 patients who had had no clinical deterioration and (2) an atypical pattern of lymphoid proliferation in three patients who experienced rapid development of non-Hodgkin's lymphoma and/or opportunistic infections. Several immunologic laboratory results paralleled these changes. Lymph node morphological findings seem to be a useful predictor of outcome in homosexual men with generalized lymphadenopathy.

Acquired Immunodeficiency Syndrome↗
PubMed1983

Malignant histiocytosis after lymphoblastic lymphoma.

Malignant histiocytosis developed in a 19-year-old boy 3 1/2 years after the initial diagnosis of lymphoblastic lymphoma of T-cell origin. The experience with this young adult suggests that a close surveillance of the survivors of lymphoma is mandatory, and a prompt biopsy of enlarged lymph nodes in patients treated for lymphoma should be a routine procedure.

Adolescent↗
PubMed1983

Clinical observation on the uterotonic effect of I-mu Ts'ao (Leonurus artemisia).

Normal fertile women given an oral dose of I-mu Ts'ao decoction (30 g. dry weight equivalent) showed an increase in intra-uterine pressure in 41.3% of 121 cases. The increase ranged from 150% to over 300% of spontaneous activity before dosing. A slightly higher success rate was observed with 2 successive doses or with improved experimental skill in later cases. Ergonovine (0.2 mg i.m.) scored a success rate of 61%. Therefore, I-mu Ts'ao decoction appeared to have a relative potency of 91% compared with ergonovine when the highest success rate (55.5%) of the former is considered. Blank control with water yield a positive response rate of 2.7%. There are no observable side-effects apart from diuresis.

China↗
PubMed1983

Treatment of Brugia malayi infection with mebendazole and levamisole.

Brugia malayi microfilaraemic patients were treated with either mebendazole 500 mg thrice daily for 21 days or a combination of a similar dose of mebendazole with levamisole hydrochloride 2.5 mg/kg weekly for 3 weeks. Although both regimes were effective, the addition of low doses of levamisole to mebendazole hastened the conversion of all patients to amicrofilaraemia, this being achieved by the second post-treatment week. No serious side reaction was encountered in the use of this high dose of mebendazole. Further experimental studies are necessary to determine whether the drug is adulticidal or only embryostatic.

Adolescent↗
PubMed1983

Acute megakaryoblastic leukemia in early childhood.

Two girls, each less than 2 yr of age, developed acute megakaryoblastic leukemia (malignant myelosclerosis). Both presented with anemia, severe thrombocytopenia, and a low percentage of blasts in their peripheral blood. Their marrow showed marked reticulin fibrosis with an increase in blasts and immature megakaryocytes. The blasts stained negatively for myeloperoxidase and Sudan Black B, but showed acid phosphatase (ACP) and alpha-naphthyl acetate esterase (ANAE) activity inhibitable by sodium fluoride. They were identified as megakaryoblasts by the platelet peroxidase reaction. Cytogenetic studies showed multiple chromosomal abnormalities in both cases. Chemotherapy with vincristine, prednisone, and L-asparaginase was without effect, while daunorubicin and cytosine arabinoside induced a complete remission in one case. The second case responded to a combination of cytosine arabinoside, daunorubicin, and 6-thioguanine. This article documents that acute megakaryoblastic leukemia occurs in early childhood and describes its clinical, pathologic, and cytogenetic features. Previous reports of childhood "myelofibrosis" are reviewed, and their possible relationship with acute megakaryoblastic leukemia is discussed.

Acid Phosphatase↗
PubMed1982

Prolymphocytic leukemia of helper cell phenotype: report of a case and review of the scientific literature.

A case of prolymphocytic leukemia was studied by using light and electron microscopy, cytochemistry and multiple immunological markers for T and B lymphocytes. Cytochemical and immunological studies showed that the cells were T-lymphocytes. By using monoclonal antibodies to human T-cell subsets, we found that these cells had the T-helper cell phenotype. The usefulness of multiparameter studies in subclassifying T-cell malignancies is discussed and the literature on T-prolymphocytic leukemia reviewed.

Female↗
PubMed1982

Plasmacytoma arising in giant lymph node hyperplasia.

Giant lymph node hyperplasia (GLNH) is generally thought to represent a benign process. A patient with GLNH of the chest wall had part of the lymph node replaced by large nodules of infiltrating plasma cells, and a serum paraprotein of the IgG lambda type. A peroxidase-antiperoxidase immunocytochemical technic showed that the plasma cells within areas of typical appearing GLNH were polyclonal, whereas those making up the nodular infiltrates were monoclonal. The observation of a plasmacytoma arising in this lesion demonstrates the neoplastic potential of GLNH.

Humans↗