Biomedical subjects

Y C Yang

Publications and source records attributed to Y C Yang.

At least 199 records · Page 11Linked to original sources

PubMed1990

Human thymic epithelial cells produce IL-6, granulocyte-monocyte-CSF, and leukemia inhibitory factor.

The development of conditions for culturing normal human thymic epithelial (TE) cells free from contaminating stromal cells has allowed us to characterize a number of cytokines produced by TE cells. Using cDNA probes for human IL-6, granulocyte-monocyte-CSF, and leukemia inhibitory factor (LIF), we identified mRNA for these cytokines by RNA blot analysis of total RNA preparations derived from TE cells. We demonstrated that TE cells produced IL-6 transcripts and that TE cell culture supernatants contained IL-6 biologic activity, as determined by the ability to support proliferation of the T1165 plasmacytoma line. The 1.0-kilobase (kb) transcript of granulocyte-monocyte-CSF was also detected in TE cell-derived total RNA. TE cell culture supernatants contained LIF activity, as determined by proliferation of the murine cell line DA-1a, and a 4.0-kb LIF transcript was detected in TE cell-derived total RNA preparations. The 4.0-kb LIF transcript from TE cell-derived total RNA corresponded in size to the LIF transcripts in PMA-activated T lymphocytes. Thus, using biologic assays and RNA blot analysis, we demonstrated that cultured normal human TE cells produced both immunoregulatory cytokines and cytokines that drive various differentiation stages of human hematopoiesis. Our findings support the hypothesis that TE cells may play a role in providing cytokines that are important for the proliferation and differentiation of hematopoietic precursor cells that migrate to the thymus during fetal and postnatal human thymic development.

Antigens, CD7↗

PubMed1990

Human P40 T-cell growth factor (interleukin-9) supports erythroid colony formation.

Because human P40 T-cell growth factor, tentatively designated interleukin-9 (IL-9), was isolated through its ability to stimulate a human IL-3-dependent leukemic cell line (M-O7E), we tested the ability of IL-9 to support the growth and differentiation of normal hematopoietic progenitor cells from peripheral blood and bone marrow. Although the M-O7E cell line was derived from a patient with megakaryoblastic leukemia, IL-9 has not proved to be a growth or maturation factor for megakaryocytes, but instead has proved to be effective in supporting the development of erythroid bursts (BFU-E) in cultures supplemented with erythropoietin. Using highly purified progenitors from peripheral blood, IL-3 showed a BFU-E plating efficiency of 46% compared with 20% for IL-9. Because of the purity of these cell preparations and the low cell density in culture, IL-9 is likely to interact directly with erythroid progenitors. Analysis of mixing experiments and of the morphology of the BFU-E in culture indicated that IL-9 interacts preferentially with a relatively early population of IL-3-responsive BFU-E. In cultures of human bone marrow or cord blood, IL-9 selectively supported erythroid colony formation, while IL-3 and granulocyte/macrophage colony-stimulating factor additionally yielded granulocyte/macrophage colonies. Therefore, IL-9 represents a new T cell-derived cytokine with the potential for selectively stimulating erythroid development in the hematopoietic system.

Antigens, CD↗

PubMed1990

Deoxyhypusine/hypusine formation on a 21,000-dalton cellular protein in a Neurospora crassa mutant in vivo and in vitro.

Hypusine formation on an 18,000-dalton cellular protein is a unique spermidine-dependent, post-translational modification that appears to be ubiquitous in mammalian cells. To determine whether this modification also exists in lower eukaryotes, we examined possible labeling in vitro and in vivo of cellular protein(s) by [3H]spermidine in a mutant strain of Neurospora crassa (arge-12 ota aga) in which ornithine and polyamine synthesis could be nutritionally manipulated. Because of poor uptake of polyamines in this organism, [3H]ornithine, the immediate precursor of polyamines, was used for the in vivo labeling experiment. Both in vitro and in vivo labeling resulted in a specific labeling of a 21,000-dalton protein. Radioactive hypusine was recovered from radiolabeled 21,000-dalton protein following acid hydrolysis. The in vitro labeling of the 21,000-dalton protein was dramatically stimulated by NAD+ and NADP+, but not by FMN or FAD, suggesting that an NAD+/NADP(+)-dependent oxidative cleavage of spermidine is involved in deoxyhypusine formation. Isoelectric focusing/sodium dodecyl sulfate two-dimensional gel analysis revealed three isoforms of the in vitro labeled 21,000-dalton protein, with pI values ranging from 5.2 to 6.5. In contrast, the 21,000-dalton protein metabolically labeled in vivo gave only one spot with a pI value of approx. 3.5.

Electrophoresis, Polyacrylamide Gel↗

PubMed1990

M-07e human leukemic factor-dependent cell line provides a rapid and sensitive bioassay for the human cytokines GM-CSF and IL-3.

We have isolated a subline of the M-07 human megakaryoblastic leukemia cell line, designated M-07e, that requires either interleukin-3 (IL-3) or granulocyte macrophage colony-stimulating factor (GM-CSF) for growth, even in the presence of fetal calf serum. This cell line will not grow long term in any other cytokine although it responds slightly to IL-2, IL-4, IL-6, IL-9, and interferon-gamma. We have used the M-07e subline to develop a quantitative bioassay for the measurement of levels of either GM-CSF or IL-3. This assay is as sensitive to either factor as the human bone marrow colony assay (CFU-GM) or the chronic myelogeneous leukemic (CML) blast cell proliferation assay for these factors and is much more convenient and reliable than either. With this assay, as little as 25-50 pg/ml of either IL-3 or GM-CSF can be detected, a level that should render the assay useful for analysis of these molecules in samples from patients undergoing colony-stimulating factor therapy and from conditioned media from natural sources of the factors. In these cases, neutralizing antisera to each cytokine are required to demonstrate the specificity of the assay. This assay, in combination with quantitative immunoassays, should greatly facilitate the analysis of the roles of IL-3 and GM-CSF in regulating hematopoiesis both in patients and in natural sources of the cytokines.

Animals↗

PubMed1990

Human interleukin 3: analysis of the gene and its role in the regulation of hematopoiesis.

Interleukin 3 (IL-3) is one of a family of cytokines believed to be important in regulating the growth and development of cells of both the hematopoietic and immune systems. In comparison with other hematopoietic growth factors, IL-3 preferentially supports the proliferation and differentiation of progenitors at early stages of hematopoietic development. In addition, IL-3 exerts a wide spectrum of biological activities on various target cell populations, including T cells, B cells, eosinophils, basophils and monocytes. The direct interaction between IL-3 and early multipotential progenitors has been confirmed in the primate model in which pretreatment of IL-3 primed the animals to become more responsive to late-acting hematopoietic growth factors, like granulocyte-macrophage colony-stimulating factor and erythropoietin. Furthermore, administration of IL-3 can diminish myelosuppression and accelerate hematopoietic recovery in primates treated with various chemotherapeutic drugs. These studies suggest that IL-3 alone or in combination with other hematopoietins may prove to be useful in treating myelosuppressed patients.

Animals↗

PubMed1990

Mitochondrial DNA of Physarum polycephalum: physical mapping, cloning and transcription mapping.

Mitochondrial DNA (mtDNA) has been isolated from four strains of Physarum polycephalum and a restriction site map has been determined using nine restriction enzymes. The restriction site maps of the four strains are similar but each strain is distinguished by insertions, deletions and restriction enzyme site polymorphisms. The sum of the restriction fragments gives mitochondrial genome sizes which vary from about 56 kb to 62 kb. In all four strains the composite map of the restriction enzyme sites for the mtDNA is circular. Knowledge of the restriction enzyme map has enabled cloning of mtDNA fragments representing the entire mtDNA of strain M3. The cloned fragments have been used to create a transcription map of the mtDNA.

Blotting, Northern↗

PubMed1990

Improved computation of respiratory resistance as measured by transiently increased resistance.

The authors have previously described an automated system for measuring total respiratory resistance. The technique used by this system involves a transient, externally applied increase in resistance to breathing. The utility of this technique is limited by a number of assumptions and to free it from the constraints imposed by one of these assumptions a new method for analysing the data was developed. The paper describes the new method of analysis and presents data comparing the resulting Rrss with those computed using the old method.

Humans↗

PubMed1990

The obstetric management in very-low-birth weight infants.

Eighty-three very-low-birth weight (VLBW) infants weighing between 500 g and 1,500 g were studied. The neonatal morbidity and mortality were 86.7% and 18.1%, respectively. Sixty-six point seven percent (8/12) of the infants weighing under 1,000 g suffered from a periventricular-intraventricular or intracranial hemorrhage (PVH/IVH) and their mortality rate was 50%. The incidence of PVH/IVH was 52.1%, and the mortality rate was 12.7% when the birth weight was between 1,000 g and 1,500 g. Forty-nine percent of the PVH/IVH took place on the first day of neonatal life, and 93% developed within 5 days after delivery. Cesarean section neither reduced the incidence of PVH/IVH nor increased the survival rate whether in cephalic or breech presentation. The incidence of PVH/IVH was not affected by type of presentation or the interval between the rupture of membranes and the delivery. Respiratory distress syndrome (RDS) and the requiring of a ventilator for ventilation significantly increased the incidence of PVH/IVH, while a low Apgar score (less than 3) at 5 minutes did not.

Apgar Score↗

PubMed1990

Role of oxygen radicals in adriamycin-induced nephrosis.

The mechanism of cellular processes responsible for proteinuria induced by adriamycin (ADR) remains unclear. In this study, we examined whether oxygen radicals contribute to the development of proteinuria in ADR-induced nephrosis. The peak concentration of malondialdehyde (MDA) of kidney was found on 8th day after ADR treatment in rats. ADR-treated rats received either superoxide dismutase (SOD, scavenger of O2-, catalase (CAT, scavenger of . H2O2) or dimethyl sulfoxide (DMSO, scavenger of OH). The SOD, CAT or DMSO treated groups had a significant suppression of urinary protein excretion, serum and renal MDA compared to ADR control group. There were also less severe renal morphologic changes in the former three groups vs the ADR controls. These data provide indirect evidence that oxygen radicals generated by ADR are important mediators of ADR-induced proteinuria.

Animals↗

PubMed1990

[Peripheral blood lymphocyte subsets in acute relapsing multiple sclerosis].

Anti-Leu series of monoclonal antibodies were used to evaluate lymphocyte subsets with ABC staining method. The peripheral blood total T cells (Tt), helper T cells (Th), suppressor T cells (Ts) and B cells were counted in 10 cases of acute relapsing MS, in which 7 cases had been investigated consecutively. Controls included 12 cases of remitting MS, 18 patients with other neurological diseases and 56 healthy subjects. The results showed that the peripheral blood Ts decreased in number and the Th/Ts ratio elevated during acute relapsing stage of MS, and they tended to return to normal when the disease showed a gradual recovery (The patients with longer periods of high Th/Ts ratio had more serious manifestations of the illness more severe disability) and the relapsing stage would be longer too.

Adolescent↗

PubMed1990

Early prenatal diagnosis of Meckel syndrome--a case report.

Meckel syndrome is a rare autosomal recessive disorder. The triad of the syndrome consists of occipital encephalocele, polycystic kidneys and postaxial polydactyly. At least two of these features are essential for the diagnosis, but other malformations such as microcephaly, cleft palate and ambiguous genitalia may also be present. The condition is considered invariably fatal. This report demonstrates that the prenatal diagnosis can in principle be established by ultrasound examination alone, and as early as 13 weeks' gestation.

Abnormalities, Multiple↗

PubMed1990

Pelvic actinomycosis associated with intrauterine contraceptive devices--a review of 6 cases.

We analysed the clinicopathologic aspects of 6 cases of pelvic actinomycosis associated with intrauterine contraceptive devices seen and treated at Mackay Memorial Hospital between 1987 and 1989. All of them had IUD for a period from 5 to 20 years. The incidence of pelvic actinomycosis among all our gynecological admission number during the same period was 0.08%. The most frequent presenting symptoms were lower abdominal pain and abnormal vaginal bleeding. An abdominal total hysterectomy with a bilateral or unilateral salpingoophorectomy was performed on all 6 cases due to a tubo-ovarian abscess or a pelvic mass. We do not find any relation between the presence of pelvic actinomycosis and the type of IUD. However, the study number was too small to make a definitive statement, but the length of time of IUD insertion is of greater significance.

Actinomycosis↗

PubMed1990

Amniotic fluid index measurement with the four-quadrant technique during pregnancy.

Eleven hundred thirty-four pregnant women with reliable dates underwent ultrasound evaluation for amniotic fluid index (AFI) measurement with the modified four-quadrant technique. We found that from 13 weeks' gestation the AFI rose progressively until 26 weeks. From then to 38 weeks the AFI measurements demonstrated little variation. After 38 weeks the AFI appeared to decline gradually. In the third trimester the mean AFI was 16.0 +/- 4.8 cm; 5% of cases had an AFI less than or equal to 8 cm, and 5% had an AFI greater than or equal to 24 cm. These results confirm the reproducibility of the semiquantitative technique and suggest that in estimating amniotic fluid volume, AFI measurement may be a more appropriate means than measurement of the single largest pocket or subjective assessment. Serial AFI measurement would be an effective way of assessing fetal status throughout pregnancy.

Amniotic Fluid↗

PubMed1990

Halothane-inhalation system for using atracurium in rats.

This report describes an inhalation anesthetic technique employed in rats. Polyethylene-glycol 400 (PEG 400) was first designed to combine with halothane to produce a slow-releasing system of vaporized halothane. This design provided adequate anesthetic levels for treating with atracurium, a new neuromuscular blocking agent. Furthermore, isoflurane was also used in this study to examine this inhalation system for treating with atracurium. The efficient concentrations of inhalated anesthetics for adequate anesthesia when combining with PEG were 0.15% and 0.1% for halothane and isoflurane, respectively. This safe efficient state of anesthesia was maintained throughout the experimental course for treating atracurium, and might be used in clinical trials.

Anesthesia, Inhalation↗

PubMed1989

Expression cloning of cDNA encoding a novel human hematopoietic growth factor: human homologue of murine T-cell growth factor P40.

We used functional expression cloning in mammalian cells to identify a cDNA clone encoding a hematopoietic growth factor that is mitogenic for the factor-dependent human megakaryoblastic leukemic cell line, MO7E. Analysis of the sequence of this cDNA revealed striking similarity to that of a recently reported novel murine growth factor for helper T-cell clones designated T-cell growth factor P40. The mRNA for the human P40 protein is expressed by several different human T-cell lines and by mitogen-stimulated peripheral blood lymphocytes. The recombinant protein displays substantial size heterogeneity typical of other glycoprotein cytokines. These properties plus the observation that this cytokine may well act within both the lymphoid and myeloid lineages warrant the designation of P40 as interleukin-9.

Amino Acid Sequence↗

PubMed1989

Evaluation of pulsed Doppler echocardiography for measurement of aortic blood flow in the fetal lamb.

The purpose of this study was to assess the accuracy of a quantitative, range-gated, two-dimensional Doppler echocardiography method for measurement of blood flow in the fetal lamb descending aorta. Comparison was made between this method and measurements determined by an electromagnetic flowmeter placed directly on the aorta in the chest of the fetus. Stroke volume was manipulated acutely either by the removal of blood, the addition of fluid by injection, or by pharmacologic means. During each procedure, descending aortic blood flow was estimated by the Doppler ultrasonography method and compared to the flowmeter recording. The size of the lumen of the aorta determined by echocardiography was correlated with direct measurement during surgery and at autopsy. A total of 359 flow measurements were obtained in 15 fetuses. Doppler ultrasonographic flow studies and electromagnetic flowmeter measurements were found to be highly correlated (r = 0.93). The study demonstrates the accuracy and reliability of the two-dimensional pulsed Doppler echocardiography method for measurement of blood flow in the descending aorta in the fetal lamb.

Animals↗

PubMed1989

Aneurysmal dilatation of the portal vein.

In the following study, a case involving an aneurysmal dilatation of the portal vein is reported. The 5-year-old boy had a 2 month history of intermittent abdominal pain. A segmental dilatation of the portal vein was noted in the sonographic examination. The portal vein aneurysm diagnosis was later confirmed by superior mesenteric angiography and computed tomography. In our review of the literature, less than 30 cases of portal venous aneurysm have been reported. To our knowledge, this is the youngest case with such an anomaly.

Arteriovenous Fistula↗

PubMed1989

Effects of intracellular free Ca and rate of Ca influx on the Ca pump.

The activity of the Ca pump of human red blood cells was studied in resealed ghosts as a function of intracellular free Ca (fCai). Resealed ghosts were made by the agarose column method to contain, in addition to other constituents, less than 0.1 microM fCai, 100 microM arsenazo III, and either 1 mM ATP plus an ATP regenerating system (active ghosts) or no added ATP and no regenerating system (passive ghosts). The rate of Ca influx into these ghosts was manipulated by suspending them in solutions containing various combinations of free Ca (1-30 microM) and the Ca ionophore A23187 (0.1-0.7 microM). Entering Ca increased the fCai and stimulated the pump in active ghosts. In passive ghosts, all the Ca movement could be described by a single rate constant. The activity of the Ca pump was calculated from the rate of net Ca uptake in the active ghosts, using the rate constant for passive Ca movement as determined in the passive ghosts. fCai and the rates of Ca transport in both active and passive ghosts were calculated from the absorbance of entrapped arsenazo III. In general, increasing fCai from 1 to 10 microM activated the pump. Higher fCai caused an inhibition compared with peak activity. The maximum rate of pumping was 80 microM/min. The major new finding is that the rate of active transport at a given fCai appeared to vary with the rate of fCai accumulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcimycin↗