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C N Lai

Publications and source records attributed to C N Lai.

8 recordsLinked to original sources
PubMed1991

Immunophenotyping of 515 cases of acute lymphoblastic leukemia in China.

Using cell surface markers and a panel of monoclonal antibodies, 515 cases of acute lymphoblastic leukemia (ALL) were immunophenotyped. T cell type ALL (T-ALL), non-T cell type ALL (Non-T-ALL) including common ALL (C-ALL), Null-ALL and B cell type ALL (B-ALL) were found. These major subtypes of ALL were further divided according to their phenotypes in detail. It was noticed that the phenotypes of these subtypes of ALL reflected basically the phenotypes of normal T or B cells at various differentiation stages or certain population of lymphocytes. The diagnosis of cell lineage was more precise when based on immunophenotyping than morphological description. The combination of morphological and immunological classification can improve the diagnosis of acute leukemias. In addition, it was observed that the immunophenotyping was relevant to clinicopathologic features, responses to therapy and prognosis of ALL patients. The incidences of major subtypes of ALL, the age distribution of ALL subsets and male sex bias with T-ALL in Chinese are discussed.

Adolescent↗
PubMed1991

[Correlation of immunophenotype with clinical features in T-cell acute lymphoblastic leukemia].

The immunophenotype of leukemicblasts from 111 patients with T-ALL or T-NHL were further examined by using a panel of standardized McAbs of CD nomenclature to human leukocyte differentiation antigens. Four major subsets of T-ALL were defined: pre T-ALL, immature T-ALL (I), common T-ALL (II) and mature T-ALL (III), with the percentages 20.7%, 20.7%, 20.7% and 37.0% respectively. In addition there was a case with M-T acute hybrid leukemia. Some of the clinical features of the patients with T-ALL and T-NHL were compared. It was found that male predominance, older age, higher leukocyte count, lower platelet level, relative higher hemoglobin level and increased incidence of extramedullary involvement, including hepatomegaly, splenomegaly and lymphadenopathy were alike for all subsets of T-ALL cases. However, the average white cell level and incidence of lymphadenopathy in the pre T-ALL subset significantly differed from those in other subsets. The correlation of immunophenotype with morphologic characterization was also discussed in this paper.

Adolescent↗
PubMed1988

Potassium inhibition of transforming protein P85gag-mos and reversal of the transformed phenotype in 6m2 cells.

K+ at high concentrations (52-72 mM hypertonic KCl) has been reported to induce reverse transformation in the 6m2 cell, which is a clone of normal rat kidney cells (NRK) infected with a temperature-sensitive transformation virus. When exposed to high K+, 6m2 cells grown at the permissive temperature (33 degrees C) exhibit normal morphology and reduced soft agar growth, characteristics of cells grown at nonpermissive temperature (39 degrees C). In the current study, flattening of cells and rearrangement of surface microvilli were demonstrated by scanning electron microscopy to occur within 6 hr of exposure to high K+, similar to the effect of temperature shift to 39 degrees C. Exposure to K+ resulted in a 90% inhibition of P85gag-mos-associated serine kinase activity within 5 min, with a subsequent reduction of up to 75% of the synthesis of this protein. These alterations in the putative transforming protein were similar to those induced by temperature shift and were considered to be the basis for retrotransformation. The cell microtubular system and F-actin cables were affected more slowly by K+ than by a temperature shift to 39 degrees C. The former did not achieve the fine reticulum network seen in NRK cells until 72 hr later, but the latter remained aberrant. The effect on the enzyme might be mediated by alteration in phosphorylation, but the mechanism by which kinase inactivation induces retrotransformation is not yet known.

Actins↗
PubMed1987

Changes in cell surface charge and transmembrane potential accompanying neoplastic transformation of rat kidney cells.

Free flow electrophoresis measurements have been used to determine the surface charge density of normal rat kidney (NRK) cells and a clone of NRK, designated as 6m2, that exhibit a transformed phenotype at 33 degrees C and a non-transformed phenotype at 39 degrees C. A clone of 6m2, designated 54-5A4, which is transformed at both 33 degrees C and 39 degrees C was also studied. A surface charge density of -1.42 microC/cm2 was obtained for the NRK and non-transformed 6m2 cells at 39 degrees C, whereas at 33 degrees C values of -1.85 and -1.78 microC/cm2 were determined for the transformed 6m2 and 54-5A4 cells, respectively. It was found that 72% of the increased charge that appeared on the transformed 6m2 cells compared with the non-transformed 6m2 cells was RNAase sensitive. The time-dependent decrease in surface charge that accompanied the shift of the 6m2 cells from their transformed to non-transformed state was found to mirror the increase in transmembrane potential previously reported using a fluorescent dye technique, and was also comparable to the reported temporal changes in their morphology and virally-coded protein content.

Animals↗
PubMed1985

Potassium-induced reverse transformation of cells infected with a temperature-sensitive transformation mutant virus.

High potassium concentrations altered the morphology and the ability to grow in soft agar in 6m2 cells, a clone of rat kidney cells infected with a temperature-sensitive mutant of Moloney sarcoma virus. Approximately 60% of cells exhibited normal morphology in the presence of 94.8 mM potassium in isotonic medium at the temperature permissive for transformation, whereas 100% were normal at 72 mM potassium in hypertonic media. A significant reduction of growth in soft agar was also induced with these conditions. However, the synthesis ratio of virus-specified transforming protein to marker viral protein was not altered. Na+K+-ATPase might play a role in this reverse-transformation process.

Animals↗
PubMed1984

Temperature-dependent transmembrane potential changes in cells infected with a temperature-sensitive Moloney sarcoma virus.

Normal rat kidney cells (NRK) infected with the temperature-sensitive (ts) transformation mutant of Moloney murine sarcoma virus yielded a clone of cells, 6m2, that exhibited a transformed morphology at 33 degrees C and a normal morphology at 39 degrees C. Transmembrane potential (Em) was measured fluorometrically using a cyanine dye diS-C3-(5). Fluorescence was inversely correlated with Em. Cells at 33 degrees C had lower Em. Em changes were recorded within 15 minutes of temperature shift from 33 degrees C to 39 degrees C in both directions, increasing in the 33 degrees C to 39 degrees C direction and decreasing in the 39 degrees C to 33 degrees C direction. Uninfected NRK cells when shifted under the same condition exhibited small fluorescence changes in the 33 degrees C to 39 degrees C direction. Shifting from 39 degrees C to 33 degrees C resulted in Em changes similar to those in 6m2 cells. Also studied was a cell line infected with a spontaneous revertant of the ts mutant, designated 54-5A4; it was transformed at both temperatures. Shifting from 33 degrees C to 39 degrees C in both directions yielded small changes. Transmembrane potential changes in 6m2 cells precede other transformation-specific changes that occur after a temperature shift.

Animals↗
PubMed1982

Alterations of bioelectric potential in primary hepatocellular carcinomas induced by N-2-fluorenylacetamide or diethylnitrosamine.

Primary hepatocellular carcinoma(s) (PHC) induced in rats by N-2-fluorenylacetamide (AAF) or diethylnitrosamine (DEN) were examined for their bioelectric potential (EP). N-2-Fluorenylacetamide-induced PHC differed from age-matched normal livers by a mean of -12.9, which is significant at p less than 0.001. They also differed from non-PHC-bearing surrounding liver by -4.75 mV, significant at p less than 0.05. Diethylnitrosamine-induced PHC differed from normal liver by -13.5 mV and from background liver by -9.95 mV, both significant at p less than 0.001. To determine the contribution of cell division to these differences, regenerating livers were examined. The levels of mixed function oxidases in PHC and in regenerating livers reported in the literature appeared to correlate with the measured EP. We, therefore, studied the effects of chemical inhibitors and an inducer of this enzyme system. The alterations of mixed function oxidase were demonstrated to parallel those of EP.

2-Acetylaminofluorene↗