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Biomedical subjects

B Lau

Publications and source records attributed to B Lau.

48 records · Page 3Linked to original sources
PubMed1979

Growth of the Reh cell line in diffusion chambers. Evidence for differentiation along the T- and B-cell pathway.

Cells of the Reh line, originally derived from an ALL of the 'Non-T, Non-B' type were cultured in diffusion chambers implanted intraperitoneally into perirradiated CBA mice. At different intervals over a period of 20 d changes in surface characteristics were examined by labelling the cells with AcALLG, ATCG as well as with polyvalent AIg. The evaluation was performed by using direct immunofluorescence. In addition, the ability to form rosetts with SRBC, AET-treated sheep erythrocytes, mouse red blood cells and EoxAC was tested. On day 0 of the diffusion chamber culture the cells only carried cALLA, and no rosette formation was observed. In the course of the diffusion chamber culture the cells unequivocally developed T-cell antigen, and in 1 of 2 experiments they further acquired a receptor for forming AET- and E-rosettes. Conversely, in the other experiment a receptor for mouse red blood cells was detected in a considerable portion of the cells. Our data show that the rather undifferentiated Reh line cells in vitro are able to develop features of mature T-cells and attributes of early B-cells during the diffusion chamber culture. In vitro they apparently retain a bivalent potentiality of lymphatic maturation. The diffusion chamber system proves to be a suitable tool for promoting differentiation in these cells.

Animals↗
PubMed1978

Successive evaluation of multiple parameters in individual cells: the SEMPIC photometric system.

An automated microphotometric system has been designed for the successive assessment of a maximum number of parameters from individual cells. The hardware and software elements are described as well as the various photometric functions that can be performed. The aim is to obtain a multiparameter analysis of morphology, cytochemistry, cell surface characteristics, and metabolic activity including cell cycle characteristics for any set of cells selected from a sample. The combination of DNA synthesis rate determination in a really quantitative approach with the analysis of features of nuclear chromatin texture opens up a new field for associating morphology with functional properties. Examples of application are presented to demonstrate the applicability of the system in a heterogeneous cell population of a very limited sample size. For this purpose, human peripheral blood cells grown in diffusion chambers in preirradiated mice were investigated. It is shown that, depending on their functions, different cell types may have quite different nuclear-to-cell area ratios. Further, a crude morphological parameter, such as the degree of basophilia of Giemsa-stained cells, may be associated with the rate of DNA synthesis, thus bearing information on the replicative activity of a cell. Cell surface properties related to the leukemia-associated cALL antigen are investigated in a human-derived cell line and correlated with cell-cycle characteristics. It is concluded that different antigenic sites rather than cell-cycle dependent differences of antigen density account for the outcome of a bimodal distribution.

Antigens, Neoplasm↗
PubMed1978

Blood volume of children with leukemia.

Blood volume was measured using 125iodinated human serum albumin in 27 children with acute lymphoblastic leukemia, and in 7 children with various types of leukemia. Total blood volume was normal in patients without marked enlargement of spleen and liver, and increased progressively as spleen and liver size increased. The hypervolemia was entirely due to expansion of plasma volume. In the children with marked hepatosplenomegaly, only hematocrit (but not red cell mass) was below the normal range in most cases. Both hematocrit and red cell mass were subnormal in the majority of patients without considerably enlarged spleen and liver. Therefore, anemia in children with marked hepatosplenomegaly may be partly caused by hemodilution of red blood cells in expanded plasma volume.

Adolescent↗
PubMed1978

Kinetics of erythroblast proliferation in states of hypoferremia.

By application of the method of quantitative 14C-autoradiography, the kinetics of erythroblast proliferation were studied in seven patients with iron-deficiency anemia (IDA), in five cases of anemia associated with infection or malignancy (ACD), and in two patients with bleeding anemia (BLA). The turnover rate of erythroblasts was significantly reduced in IDA and ACD, and was normal in BLA. Proliferation and maturation of erythroblasts in IDA and ACD were increasingly slowed down with advancing development into mature cells. Neither changes in the number of cell divisions nor ineffective erythropoiesis were observed within the proliferative compartments. The kinetic impairments found in IDA and ACD could readily be counterbalanced by a twofold increase in the rate of stem cell differentiation. Within recognizable erythropoiesis, no compensatory effort was detectable, not even in proerythroblasts. Insufficient compensation at the stem cell level is therefore regarded as the prime lesion in IDA and ACD.

Anemia↗
PubMed1977

[Erythropoiesis in iron deficiency].

The kinetics of erythroblast proliferation were studied by means of quantitative 14C-autoradiography in 5 patients showing anemia due to infection or malignancy, in 7 patients suffering from iron deficiency anemia, and in two individuals with bleeding enemia. Compared with a group of 5 healthy persons a markedly reduced turnover of erythroblasts was found in the anemia due to infection, malignancy, and iron deficiency, whereas this turnover was normal or increased in the case of bleeding anemia. The reduction is caused by a progressively decreasing rate of erythroblast proliferation and maturation with advancing development into mature cells. No indications of a change in the number of cell divisions were found in the anemia of infection, malignancy, and of iron deficiency, nor was there evidence of an intramedullary death of nucleated red cell percursors. The imbalance between production and loss of red cells causing anemia shows a different pattern in the 3 groups of disease: In bleeding anemia the insufficiency of supply is not yet apparent from the rate of erythroblast turnover giving weight to the factor of blood loss. In anemia due to infection, malignancy, and iron deficiency the but moderately increased rate of red cell destruction cannot be compensated because of several impairments: The rate of erythroblast turnover is reduced, and, in addition, a moderate portion of maturing cells is destroyed, probably at the reticulocyte stage. As the most significant factor, the bone marrow is unable to compensate the anemia by an effective erythroblast hyperplasia. In iron deficiency this hyperplasia is inadequately low, in infection and malignancies, however, it is more or less missing.

Anemia↗
PubMed1976

Bone marrow hypoplasia in anorexia nervosa.

Within a 2-year period, from March 1974 until May 1976 10 patients with anorexia nervosa were seen at the children's university hospitals of München (2 patients) and Giessen (8 patients). The patients were 10-16 years old, with one exception all girls, and had the typical cachexia, hypothermia, bradycardia, gray, hairy skin, and amenorrhea in those who had reached menarche. The blood counts at diagnosis revealed a leukopenia (below 5000/mm3) in 6 patients and a thrombocytopenia (below 150000/mm3) in 4 patients. The bone marrow was examined in 7 patients and showed marked hypocellularity with only few megakaryocytes present and abundant vacuolated hyaline material. Bone marrow erythroblasts were decreased (below 20%) in 5 patients, although peripheral blood hemoglobin and hematocrit were normal or even elevated in all 10 patients. In 7 patients blood urea nitrogen was elevated above 30 mg%, the highest value being 145 mg%. Blood and bone marrow alterations as well as the renal abnormalities disappeared within days to a few weeks after a regimen of strict fluid and caloric intake was initiated and a gain in body weight of up to 10 kg was achieved.

Adolescent↗
PubMed1975

[Acute lymphoblastic leukemia after tuberculosis in a 8-year old greek boy with homozygous beta-thalassemia (author's transl)].

A greek boy is described in whom pulmonary tuberculosis and homozygous beta-thalassemia was discovered at 4 years of age. Tuberculosis was cured after 1 year of combined tuberculostatic chemotherapy. His thalassemia only required 1-2 blood transfusions per year. Acute lymphoblastic leukemia was diagnosed in the patient at 8 years of age and treated with antileukemic combination chemotherapy and cranial irradiation. 7 months after diagnosis the boy is still in continuous complete remission under antileukemic chemotherapy without requiring blood transfusions.

Blood Transfusion↗
PubMedDate not supplied

[Membrane differentiation of acute lymphoblastic leukemia from cALL-type cells in diffusion chambers].

In order to explore their differentiation capacity peripheral blasts from 4 children with acute lymphoblastic leukemia of the common type (cALL) as well as cells of the Reh line were cultured in diffusion chambers implanted intraperitoneally into preirradiated CBA mice (8 gy). At various times after initiation of the culture, changes in the membrane marker profile were studied by investigation of surface antigens and rosetting phenomena. In the course of the culture, the cells of two patients, T. H. and I.G., developed surface immunoglobulin (sIg) in combination with the CALL antigen (cALLA). Simultaneously, the cells of I.G. containing cytoplasmic Ig prior to cultivation acquired a receptor for mouse erythrocytes (EM). Besides quite a few cells developing the T-cell antigen, the majority of the cell yield in patient V.M. expressed sIg alone or together with the cALLA. Comparable results together with an increasing portion of mouse rosette forming cells were obtained in the fourth patient, C.M. In case of the Reh-line the cells developed the T-cell antigen, and in one of two experiments they further acquired a receptor for sheep erythrocytes. conversely, in a second experiment and EM-receptor was detected. Our data suggest that leukemic blast cells carrying the cALLA are representative of an early developmental stage of lymphatic ontogeny.

Animals↗