Economic development with limited supplies of family labor: Chinese peasant families in balancing demographic and economic requisites.
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Asia↗
Biomedical subjects
K S Chang
Publications and source records attributed to K S Chang.
An evolutionary view of viral regulatory genes.
It is my great honor to dedicate this article to Professor Ludwig C. Yen at the occasion of the Annual Meeting of the Chinese Society of Microbiology, commemorating his 101st Birthday. I have had the privilege of being one of the earliest students of Professor Yen, and as a staff member working for 16 years under him, I have been benefited enormously from his teachings. I am most grateful to Dr. Czausiung Yang and the executive board members of the Chinese Society of Microbiology for giving me this opportunity to present some of my research activities which would be relevant to Professor Yen's teachings. Introduction to the evolutionary view of host-parasite relationship was one of the many contributions Professor Yen made to enlighten students and colleagues as early as in 1940. As promulgated by Professor Yen, natural history of infectious diseases has witnessed the reality of Theobald Smith's premise, "pathogenicity of microorganisms is an accident in the evolutionary processes of host-parasite relationship, and the outcome of evolutionary forces is a modus vivendi (a feasible compromise) according to which the parasite and the host reach some sort of equilibrium which permits the survival of both"(1). These evolutionary concept has since become a common knowledge for modern students of infectious diseases. The natural history of recently discovered human retroviruses such as HTLVs (human T-lymphotropic viruses) and HIVs (human immunodeficiency viruses) has amply demonstrated the truth of the premise. I shall review some results of our research which would be of relevance to the evolution of viral quasispecies and variants, viral oncogenes, and the cellular as well as viral regulatory genes. I shall focus on the roles played by these genes in the delicate and complex balance of host-virus relationships, and on their association with cellular differentiation and oncogenesis.
Biological Evolution↗
Down-regulation of c-Ki-ras2 gene expression associated with morphologic differentiation in human embryonal carcinoma cells treated with berberine.
A pluripotent human embryonal carcinoma (EC) clone, NT2/D1, which was derived from the Tera-2 cell line, was induced to differentiate into cells with neuronal-like cell morphology by treatment with berberine, an alkaloid derived from a Chinese herbal medicine (Huang Lien). As early as one day after 24-hour treatment of cells with berberine at a nontoxic dose of 0.1 mg/ml in culture medium, the cells started to show morphologic changes, developing into terminally differentiated neuronal-like cells with long, inter-connecting network cellular structures. This process was much faster as compared with that induced by treatment with retinoic acid (RA), which took at least several days to develop. Unlike RA, berberine could not induce murine EC cell line, F9, to differentiate into endodermal cells. It was also found that although the NT2/D1 cell clone exhibited amplification and enhanced mRNA expression of c-Ki-ras2 gene as did the parent cell line, a marked down-regulation of c-Ki-ras2 mRNA expression was observed. However, there was no change in actin mRNA expression even after differentiation had occurred. Thus, morphologic differentiation of EC cells into neuronal-like cells was found to be associated with down-regulation of a protooncogene which plays some definite role in oncogenesis. The mechanism by which berberine induces differentiation in these cells needs further investigation.
Actins↗
[Enhanced myocardial depression from bupivacaine in diabetic rats].
We examined the direct effects of bupivacaine on the diabetic rat myocardium using an isolated perfused (Langendorff) heart preparation. Rats were made diabetic by injection of streptozotocin (55 mg.kg-1, i. v.). 12 weeks after the administration of streptozotocin, hearts were excised and perfused using Langendorff technique. Following 60 min for equilibration, diabetic hearts from the 12-week animals exhibited significant bradycardia. Bupivacaine 3 mcg.ml-1 did not decrease myocardial contractility in control animals. However, 3 mcg.ml-1 bupivacaine decreased contractility significantly in diabetic animals at nearly all periods. Bupivacaine decreased heart rate and coronary flow significantly and similarly in control and diabetic rats hearts. After pacing at 4 Hz, bupivacaine decreased contractility more in diabetic group than in control group. These results indicate that the presence of a diabetic state appears to enhance the sensitivity of the heart to the myocardial depressant effect of bupivacaine.
Animals↗
Rearrangement of the retinoic acid receptor gene in acute promyelocytic leukemia.
The retinoic acid receptor-alpha (RAR-alpha) gene was previously localized to chromosome 17q21, a region close to the t(15;17) (q22;q21) abnormality in acute promyelocytic leukemia (APL). We used the RAR-alpha gene as a probe and found that eight of nine APL patient samples with t(15;17) (q22;q21) showed rearranged bands. A tenth APL patient was diploid and demonstrated no rearrangement. One patient who had rearrangement as an acute leukemia did not have rearrangement in remission. The results obtained from intron/exon mapping of the RAR-alpha gene demonstrated that breakpoints of seven of the eight patients occurred within intron 1. Northern blot analysis of leukemic samples indicated the expression of two RAR-alpha mRNA of 2.7 and 3.7 kb. However, two additional mRNA of 4.1 and 3.2 kb were found in an APL patient. We conclude that the RAR-alpha gene is directly involved in the t(15;17) translocation in APL and may transcribe aberrant messages.
Blotting, Northern↗
Down regulation of myeloperoxidase gene associated with specific nuclease hypersensitive sites during TPA induced differentiation of HL-60.
The level of myeloperoxidase (MPO) mRNA is reduced significantly after HL-60 induced differentiation with the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). We examined the chromatin structural changes of the MPO gene during TPA induction. Before TPA induction about nine DNase I hypersensitive sites (HS) were found on the 5' upstream and at various intron regions of the MPO gene. A new HS was found on intron 8 within 4 h of induction; its appearance preceded down regulation of the MPO gene. At the same time DNase I HS found in 0.3 and 1-1.5 kb upstream of the MPO CAP site, were significantly reduced or disappeared after TPA induction. These chromatin structural changes could be closely linked to the mechanism which regulates the MPO gene expression.
Blotting, Southern↗
Berberine-induced morphologic differentiation and down-regulation of c-Ki-ras2 protooncogene expression in human teratocarcinoma cells.
A pluripotent human teratocarcinoma cell clone, NT2/D1, which was derived from the Tera-2 cell line, was induced to differentiate into cells with neuronal cell morphology by treatment with berberine. As early as 1 day after a 24-h treatment of cells with berberine at a non-toxic dose of 0.1 mg/ml in culture medium, the cells started to show morphologic changes, developing into terminally differentiated neuronal cells with long, inter-connecting network-like cellular structures. This process is much faster as compared with that induced by treatment with retinoic acid (RA), which took at least several days to develop. Unlike RA, berberine could not induce murine teratocarcinoma cell line, F9, to differentiate into endodermal cells. It was also found that, although the NT2/D1 cell clone exhibited amplification and enhanced mRNA expression of c-Ki-ras2 gene as did the parent cell line, a marked down-regulation of c-Ki-ras2 mRNA expression was observed. However, there was no change in actin mRNA expression even after differentiation had occurred. Thus, morphologic differentiation of teratocarcinoma cells into neuronal cells is found to be associated with down-regulation of a protooncogene which plays some definite role in oncogenesis. The mechanism by which berberine induces differentiation in these cells needs further investigation.
Animals↗
Socialist institutions and family wealth flows reversal: an assessment of post-revolutionary Chinese rural fertility.
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China↗
Developmental and differential regulation of human MPO gene in leukemic cells.
Northern blot analysis of RNA isolated from HL-60 cells before and after differentiation induction by TPA and DMSO showed that four MPO mRNA species (3.3, 3.1, 2.7, and 2.5 kb, respectively designated alpha 1, beta 1, alpha 2, and beta 2) are expressed in HL-60 cells. However, alpha 2 and beta 2 lack part of the 3' end sequence due to different polyadenylation sites. The steady state levels of alpha 2 and beta 2 MPO mRNA increase significantly after 1 hr of induction, while all four MPO mRNA species decrease dramatically after 10 hr of induction. Our results demonstrate that MPO gene expression is developmentally and differentially regulated. Northern blot analysis of RNA isolated from blast samples of acute myelogenous leukemia (M0-M5) and chronic lymphocytic leukemia (CLL) patients indicate that four MPO mRNA species are expressed in M1-M4 but are undetectable in M5 and CLL. Primer extension and S1 nuclease protection analysis of the MPO mRNA revealed a single transcription initiation site for the MPO gene.
Base Sequence↗
Histamine relaxation of aortic rings from diabetic rats.
The effect of histamine-induced relaxation on thoracic aortic rings from rats 5, 12, 24 and 52 weeks following streptozotocin-induced diabetes was determined. Preliminary studies confirmed the dependence of histamine-induced relaxation and the independence of nitroglycerin-relaxation (GTN) on the presence of endothelium (EDRF). Diabetes was confirmed by blood glucose levels exceeding 300 mg/dl. Rings with endothelium were depolarized several times with 50 mM KCL and then contracted with phenylephrine (10(-6)). Dose-response curves were plotted from data obtained following exposure to histamine (10(-7)-10(-3)) and GTN (10(-9)-10(-7)) and compared to responses from age-matched untreated controls, diabetic and diabetic rats treated with insulin (2 U/day). The relaxation produced by histamine on phenylephrine pre-contracted rings was similar in all three groups from 5-week age matched rats. However, histamine-induced relaxation from untreated diabetic rats was significantly depressed at 12, 24 and 52 weeks (p less than 0.001). Conversely there was no difference in the relaxation elicited by GTN on rings obtained from the three groups at any age. Pretreatment with diphenhydramine (5 x 10(-7)) on aortic rings from 12 and 52-week age matched rats resulted in qualitatively similar histamine dose-response curves that were displaced about two orders of magnitude to the right, indicative of H1 receptor competitive antagonism. These results demonstrate that the duration of diabetes alters the responsiveness of rat thoracic aortic rings to histamine but not to GTN and suggests that the responses elicited by certain agonists on target tissues may be significantly altered depending on the duration of diabetes.
Animals↗
Effect of age and methacholine on the rate and coronary flow of isolated hearts of diabetic rats.
1. Isolated hearts perfused by the method of Langendorff from 6, 12 and 24 week streptozotocin (STZ) diabetic rats displayed a significant bradycardia following 60 min equilibration. The rate of hearts from 12-week diabetic rats (164 +/- 17) displayed the greatest bradycardia compared to age-matched controls (268 +/- 15; P less than 0.001), and diabetics treated with insulin (232 +/- 17; P less than 0.01), but by 52 weeks the heart rate of the 3 groups was similar. With advancing age the effect of STZ diabetes on the rate of rat isolated perfused hearts remained unchanged but the rate of the control and diabetic + insulin groups declined. 2. Hearts from 6-52 week STZ-treated rats were found to be more sensitive to the negative chronotropic effect of methacholine, the greatest difference occurring in hearts from the 12 week animals. Atropine (10(-7) M) did not affect the resting heart rate of age-matched controls or diabetics but blocked methacholine (2.6 x 10(-6) M)-induced bradycardia in both, suggesting that the site of action of diabetic bradycardia is not the muscarinic receptors. 3. At the end of equilibration there was a significant decrease in coronary flow in hearts from 12 week diabetic animals. In spontaneously beating diabetic rat hearts administration of methacholine (2.6 x 10(-6) M) produced a significantly greater decrease in coronary flow in the 12, 24 and 52 week diabetic hearts. When electrically paced (5 Hz) however, there was no difference in response to methacholine between the three groups except at 52 weeks between the age-matched control and diabetic groups. This suggests that the more pronounced reduction induced by methacholine on the coronary flow of diabetic hearts is secondary to its negative chronotropic effect. 4. In general, hearts from diabetic animals treated with insulin respond similarly to their agematched controls in the presence and absence of methacholine.
Aging↗
Genetics in heart diseases.
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Cardiomyopathy, Hypertrophic↗
Variants of amphotropic type-C retrovirus isolated from cultures of Moloney- and Rauscher-MuLV-induced tumors.
We isolated and characterized 2 strains of type-C retrovirus, R5NX and YACNX, from established lymphoid cell cultures derived from Rauscher-MuLV-induced lymphoma (RBL-5) in a C57BL/6 mouse, and Moloney-MuLV-induced lymphoma (YAC) in an A-strain mouse, respectively. The R5NX and YACNX viruses were compared with the prototype 4070A strain of amphotropic virus isolated from feral mice in California, and were found to belong to the same amphotropic virus class on the basis of viral interference, neutralization tests, and other biological properties. However, they were not quite identical with respect to viral neutralization antigens and restriction enzyme cleavage patterns of the proviral DNA. The possibility that these viruses may have been present in the original tumor together with the R-MuLV or M-MuLV as "exogenous" viruses rather than as contaminants of cell cultures by the 4070A virus is discussed. Although these 2 isolates were not pathogenic when inoculated into newborn C3H/HE mice, they could establish persistent infections in these mice.
Animals↗
Concomitant infection of HTLV-I and HIV-1: prevalence of IgG and IgM antibodies in Washington, D.C. area.
Serum samples collected from four groups of individuals in the Washington, D.C. area were examined for the presence of IgG and IgM classes of antibody reacting against HTLV-I and HIV-1. These four groups were: (1) healthy adults with negative premarital VDRL test for syphilis (n = 113), (2) miscellaneous common disease patients (n = 155), (3) drug abusers (n = 130), and (4) homosexual men (n = 187). The former two groups are considered to be low-risk groups, and the latter two, high-risk groups. The prevalence of IgG antibody on ELISA/Western blot tests for these groups were respectively: (1) 5.3%/1.8%, (2) 5.2%/1.9%, (3) 13.9%/4.6%, and (4) 4.3%/1.6% for HTLV-I, and (1) 2.7%/0.9%, (2) 4.5%/0%, (3) 12.3%/5.4%, and (4) 8.0%/5.9% for HIV-1. Instances of possible concomitant infection as shown by the presence of antibodies against both HTLV-I and HIV-1 were found only in the latter two high-risk groups, i.e. two (1.5%) in group (3), and three (1.6%) in group (4) as confirmed by both Western blot and immunofluorescence tests. Out of 97 sera collected from drug abusers in 1985-86 which had IgG antibody by Western blot test against HIV-1, 23 (23.7%) were HTLV-I antibody positive by ELISA test (Group 5), and 8 of these were confirmed by Western blot test. Among these 8 persons, IgM antibody against HTLV-I was found in 2, while that against HIV-1 was positive in 7 persons.(ABSTRACT TRUNCATED AT 250 WORDS)
Acquired Immunodeficiency Syndrome↗
The myeloperoxidase gene is translocated from chromosome 17 to 15 in a patient with acute promyelocytic leukemia.
This study demonstrates that a differentiation-specific gene, the myeloperoxidase (MPO) gene, is translocated in a patient with acute promyelocytic leukemia (APL). The MPO gene recently has been mapped to chromosome #17, close to the breakpoint involved in the t(15;17) commonly seen in APL. By in situ hybridization, we showed that this gene was translocated from chromosome #17 to #15 in an APL patient. Although the significance of this translocation remains unclear, MPO is known to be highly expressed in APL. The causal relationship between the high expression and translocation of this gene requires further investigation.
Chromosome Banding↗
Effects of a sonographic technique for determining chest wall thickness in treatment planning for breast carcinoma.
This study investigated the use of a sonographic technique of determining chest wall thickness and the impact of dosimetric correction for lung inhomogeneity on treatment planning for breast irradiation after lumpectomy or partial mastectomy. The thickness of the chest wall in three planes of the radiation field was obtained using a B-mode ultrasound scanner and the location of the pleura-lung interface was marked on the contour of the chest wall in each plane. Treatment plans for 88 patients were developed with and without correction for the lung tissue included in the radiation volume. All patients were irradiated with an opposing pair of tangential fields to the breast with a 6 MV X ray beam using an isocentric set-up. Within the treatment volume, dose variation of +/- 5% of the prescribed tumor dose was aimed for in the treatment planning. With correction for lung tissue, the proportion of treatments given with a wedge filter was found to be on the average 20% less than it would be without lung correction. The described sonographic technique is simple to perform and reproducible. It improves the accuracy of dosimetry in treatment planning for breast carcinoma.
Breast Neoplasms↗
Peripherization of immigrant professionals: Korean physicians in the United States.
Using data on the characteristics of 1043 physicians who graduated from a medical school in Korea, the authors analyze the effects of immigrant status, gender, and year of graduation on their choice of medical practice specialty. The specialty areas are categorized into 2 groups, "core" and "periphery," on the basis of the reported median income of practitioners in each specialty. The results of log-linear model analyses indicate that female physicians are more likely to immigrate to the United States than male physicians, although the general trend of immigration does not notably change over time. In the main equation, immigration status shows a significant peripheral effect as immigrant physicians are much more likely to practice in peripheral areas than their home-staying counterparts. Gender status is also found to have a significant peripheral effect. When these Korean immigrant physicians are compared with the US-educated physicians in regard to their areas of practice, the same pattern of peripherization is observed among the immigrants. The findings suggest that, despite their secular image of "success," immigrant professionals in the United States carry on the same kind of marginal economic activities within the professional labor market as unskilled immigrant workers do within the nonprofessional labor market.
Americas↗
Detection of minimal residual bcr/abl transcripts by a modified polymerase chain reaction.
The Philadelphia (Ph1) chromosome in chronic myelogenous leukemia (CML) involves reciprocal translocation of the bcr gene and the c-abl oncogene. The fused bcr/abl gene is transcribed into two types of chimeric mRNA. By means of a combined method of S1 nuclease protection and polymerase chain reaction, we amplified sequences representative of the chimeric bcr/abl transcripts. Only 5 micrograms of total cellular RNA is needed and the chimeric bcr/abl message can be detected at a dilution of 1:100,000. We also detected residual chimeric bcr/abl transcripts in the remission samples from two Ph1-positive CML patients. This technique has the potential to identify a subpopulation of Ph1-positive CML patients in remission who are at high risk of relapse.
Base Sequence↗