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Biomedical subjects

C T Wu

Publications and source records attributed to C T Wu.

At least 91 records · Page 5Linked to original sources
PubMed1989

Studies on the suppression of HL-60 cell growth in vitro by low molecular weight suppressor of human fetal liver origin.

In human fetal liver there are at least two kinds of cell growth suppressor, arginase and a low molecular weight suppressor, both are cytotoxic towards HL-60 cells under the condition of in vitro culture, and mainly present in the supernatant of fetal liver cell suspension. As compared with arginase, the low molecular weight suppressor shows a preferential suppression on HL-60 cell growth rather than that of granuloid-macrophage progenitors of normal human bone marrow.

Arginase↗
PubMed1989

The Drosophila zeste gene and transvection.

The zeste locus of Drosophila melanogaster encodes a DNA-binding protein that can influence transcription. A number of sites recognized by this protein fall within genes associated with transvection, a phenomenon suggesting a form of gene regulation that is responsive to the proximity of a gene to its homologous allele on another chromosome. These recent observations continue a history of studies concerning zeste and transvection which has inspired molecular models linking chromosome structure and positioning to the modulation of gene expression.

Alleles↗
PubMed1989

Translation of poly(A)+ mRNA encoding CFU-S proliferation stimulator of human fetal liver origin in Xenopus laevis oocytes.

Using the sodium dodecyl sulfate/chloroform/phenol method, total RNA was extracted from human fetal liver tissue with a yield of 870-1060 micrograms/g of tissue; mRNA was obtained after chromatography on an oligo(dT)-cellulose column. Experimental studies demonstrated the translation of a poly(A)+ mRNA encoding proliferation stimulator of human fetal liver origin in Xenopus laevis oocytes.

Animals↗
PubMed1989

[Effect of a human fetal liver factor in suppression of HL-60 cell growth in vitro].

Two kinds of HL-60 cell growth suppressors present in human fetal liver were studied. One is the known arginase which shows non-specific suppression on the growth of HL-60 cells and human granulocyte-macrophage progenitors (CFU-GM), and the other, a new species of suppressor with a lower molecular weight (less than 10,000 daltons), shows preferential suppression on HL-60 cell growth, but less suppressive effect on the growth of CFU-GM.

Cell Division↗
PubMed1989

[Access cavity preparation for mandibular incisors with suspected two canals].

One of the common reasons for endodontic failure is incomplete root canal obturation. According to previous studies, about 10-45% of all lower incisors have two canals. The purposes of this study were: 1. determine the incidence of double canals in the lower incisors among Chinese; 2. evaluate the usefulness of X rays for locating double canals in the lower incisors; and 3. propose a method of access cavity preparation for lower incisors when double canals are diagnosed. One hundred lower incisors were collected and checked by dental X ray, mesiodistally, buccolingually and at a 30 degrees mesial shift, in order to determine the incidence of double canals and evaluate their images on film. In addition, a method for drawing the pathway of the double canals from the apex to the incisal edge, as a reference for access cavity preparation, was proposed. The results of this study showed that 36 out of the 100 lower incisors had double canals and only two of them had two separate apical foramina. Clinically, when the X ray image of the lower incisor canal is obscure or missing at the middle third of the root, it is best to extend the access cavity to the incisal edge in order to find the lingual canal.

Dental Cavity Preparation↗
PubMed1989

Effects of human fetal liver extract on the growth of HL-60 cells.

Two kinds of HL-60 cell growth suppressor present in human fetal liver were studied. One is the already known arginase, which showed nonspecific suppression on the growth of HL-60 cells and human granulocyte-macrophage progenitors (CFU-GM), and the other, a new species of suppressor with the characteristics of lower molecular weight (less than 10,000 daltons), shows preferential suppression on HL-60 cell growth, but less effect on the growth of CFU-GM.

Arginase↗
PubMed1987

Kinetics of the clonal proliferation of granulocytes and macrophages in cultures of mouse bone marrow cells as supported by two distinct types of colony-stimulating factors.

Two different types of colony-stimulating factors (CSF) were used to support the clonal growth of myeloid progenitor cells (CFUc) in semi-solid agar or viscous methylcellulose cultures of mouse bone marrow cells. The cultures stimulated for 5 days with RSP-2-P3 cell CSF (CSFRSP) contained mainly granulocyte colonies, whereas the cultures stimulated for 10 days with human urine CSF (CSFhu) contained mainly monocyte/macrophage colonies. Four lines of study were carried out: 1) a kinetic study using combinations of the two types of CSFs in the same culture; 2) a study of transferring CFUc from the initial 3-day cultures to recipient cultures containing the same or different types of CSF; 3) an examination of the morphology over time of colonies that were confined by glass capillaries plunged in agar; and 4) electron microscopic observations on disintegrating granulocytes. The results of all these lines of study suggest that about one third of the CFUc can be stimulated both by CSFRSP and CSFhu while the other two thirds react specifically either with CSFRSP or with CSFhu. The present study also suggests that granulocytes in the culture stop proliferation and disintegrate while macrophages are still growing there. Thus, mixed-type colonies containing both macrophages and granulocytes later become macrophage colonies.

Animals↗
PubMed1986

Characteristics of hemopoietic stem cells determined by single spleen colony transplantation.

By using a spleen colony transfer technique and sex chromosome determinations as a cytogenetic marker, we compared the spleen colony-forming cells of bone marrow origin from three strains of mice, i.e., LACA, C57, and (LACA female X C57 male) F1. The proliferation potential of spleen colony-forming cells was found to be heterogeneous in nature. Some of the cells have the essential characteristics of hemopoietic stem cells (Ps-CFUS), i.e., the capacity for sustained proliferation and differentiation into myeloid and lymphoid lineages of cells, whereas others exhibit the capacity to form gross colonies on irradiated recipient spleen which are capable of differentiating different lineages of blood cells, but have lost the ability to reconstitute hemopoiesis in lethally irradiated recipients (Pg-CFUS). The results of studies on spleen colony-forming cells of F1 mice indicate the existence of a subpopulation of primitive precursors of spleen colony-forming cells (Pre-CFUs) which are not able to form spleen colonies on recipient spleens, but, under appropriate stimuli, may assume the properties of Ps-CFUS. Therefore the sequential process of blood cell differentiation may be described as follows: Pre-CFUS----Ps-CFUS----Pg-CFUS----different lineages of hemopoietic progenitors----different lineages of blood cells.

Animals↗
PubMed1985

Comparative studies on the characteristics of proliferation and differentiation of spleen colony-forming cells.

Using a single spleen colony transplantation technique and sex chromosome typing as a natural cytogenetic marker, most spleen colony-forming cells (CFC) in adult bone marrow or fetal livers of inbred LACA or C57 mice re-established hemopoiesis in lethally irradiated mice when the spleen colonies were sampled at 13 days after transplantation. However, most of the spleen colony-forming cells in the peripheral blood of normal mice possess little potential for proliferation and are less efficient in the re-establishment of hemopoiesis in lethally irradiated mice. The CFC population is heterogeneous in the mice. From the subsequent retransplantation of colonies from colony-forming cells in the peripheral blood, the simple assessment of spleen colony-forming units (CFU-s) content, based on the number of splenic colonies, does not reliably represent the content of hemopoietic stem cells.

Animals↗
PubMed1984

Serum zinc, copper, and ceruloplasmin levels in male alcoholics.

Twenty male alcoholics aged 29 to 69 years (mean 45.80 + SD 10.97) were compared with controls for serum zinc, copper, and ceruloplasmin levels. The serum zinc level of the alcoholic patients was significantly lower than that of the control group (t = 3.3005, p less than 0.005). The serum copper and ceruloplasmin levels of the alcoholics tended to be higher than those of the controls, but the difference was not statistically significant. A significantly positive correlation between serum zinc and albumin levels (r = 5.41, p less than 0.01) was also found. The nutritional state of the alcoholics may not be an adequate explanation for their low serum zinc level. It is suggested that further research on alcohol as a toxic agent might focus on trace element-containing enzymatic defects in brain peptides and hormones to promote fuller understanding of the psychopathology associated with alcohol abuse.

Adult↗
PubMed1982

Interactions of zeste mutations with loci exhibiting transvection effects in Drosophila melanogaster.

Zeste (1-1.0; 3A3) mutations have been known to modify the expression of two gene complexes: white (1-1.5; 3C1.5) and bithorax (3-58.8; 89E1-4) in Drosophila melanogaster. Certain mutations of these complexes have been shown to behave in a synapsis-dependent fashion. That is, certain bithorax and white genotypes exhibit one level of expression when the two copies of these loci are able to synapse in somatic tissues and another level when heterozygosity for chromosomal rearrangements interferes with their ability to pair. Such phenomena are termed transvection effects by LEWIS (1954). In the case of the white locus, asynapsis leads to a more normal state, whereas at bithorax, asynapsis leads to a more mutant phenotype. Recently, a third case of transvection was described at the decapentaplegic (2-4.0; 22F1-3) gene complex (GELBART 1982); phenomenologically, it is very similar to transvection at bithorax. In this report, we demonstrate that zeste mutations can also interact with those decapentaplegic mutations that exhibit transvection effects. In addition, we present more information on the zeste interactions with white and bithorax. Interactions with zeste may be diagnostic of loci that can exhibit transvection effects. However, different groups of zeste alleles interact with each complex. z1 interacts with white, za alleles interact with bithorax and all tested zeste mutants interact with decapentaplegic. These differential effects of zeste mutations may be a reflection of the neomorphic nature of the z1 allele.

Animals↗
PubMed1979

Flow cytometric prescreening of cervical smears.

One-parameter (nuclear DNA) and two-parameter (nuclear DNA and protein or cellular light scatter) measurements of cervical smears were performed using an ICP 11 and a cytofluorograf 4800 respectively. A total of about 1000 cases was analyzed. For the estimation of nuclear DNA alone two fluorochromes were tested (ethidium bromide (EB) and mithramycin (MMC)) combined with three different methods of cell preparation. For the two-parameter measurements cells were double stained with EB and fluorescein isothiocyanate (FITC). Red fluorescence (EB) versus green fluorescence (FITC) or red fluorescence versus scatter were recorded. A computer analysis of the one-parameter histograms was performed using discriminant analysis and the results were compared with the cytodiagnosis of microscopic specimens stained with the Papanicolaou technique. The error rates of the flow cytometric (FCM) data were as follows: (a) standard EB staining, 11% false negative, 26% false positive, 6% unsatisfactory results; (b) pepsination of vital cells and EB staining, 12% false negative, 14% false positive and 4% unsatisfactory results; (c) MMC staining, 10% false negative, 65% false positive and 5% unsatisfactory results. Our two-parameter measurements prove that, as confirmed by cell sorting, red fluorescence versus scatter allows separation of at least three subpopulations in most analyzed samples: (a) anucleated cells; (b) leukocytes; and (c) intermediate and superficial cells.

Cell Nucleus↗