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Biomedical subjects

T Wang

Publications and source records attributed to T Wang.

At least 829 records · Page 46Linked to original sources
PubMed1980

Amniotic epithelium in diabetes mellitus. Light and electron microscopic examination.

The epithelium of human amnion was examined under the light and electron microscopes. Morphologically, the amniotic epithelium in diabetes mellitus differs from that of a normal term specimen by the following characteristics: 1. An increase in the number of beta-shaped glycogen granules and lipid droplets; 2. The presence of epithelial areas with dead cells; 3. Thickening of the basal membrane. Areas with dead cells could be identified in the amniotic epithelium of diabetic patients. These were not found in normal term pregnancies nor in other types of high-risk pregnancies, such as non-diabetic hydramnios, rhesus incompatibility, or pretoxaemia/toxaemia. These findings may indicate that the areas are specific to diabetes mellitus.

Amnion↗
PubMed1980

The induction and detection of diploid spermatozoa in Gallus domesticus.

Colcemid at the dose level of 0.37 mg/kg/day was injected intraperitoneally to 3 sexually active chicken males for 3 consecutive days. 10-12 days after the first colcemid injection, 14-25% of the sperm population in the semen samples from the treated males was found to be diploid in DNA content by flow microfluorometric analysis. Cytogeneic and developmental analyses on early embryos indicate that, during the process of spermatogenesis, the male germ cells are most susceptible to colcemid treatment 10-12 days prior to the maturation of the spermatozoa which is equivalent to the primary through secondary spermatocyte stages in chicken males. By the application of an extremely unequal chromosomal translocation as a cytological marker of parentage, it is confirmed that the diploid sperm induced are capable of uniting with a normal haploid or diploid egg to produce a triploid or tetraploid zygote.

Animals↗
PubMed1980

Effects of RMI 12330A, a new inhibitor of adenylate cyclase on myocardial function and subcellular activity.

1 RMI 12330A, a lactam-imine, at concentrations of 10(-4) M and higher, inhibited basal as well as isoprenaline and NaF-stimulated adenylate cyclase activity of guinea-pig heart homogenates. However, RMI 12330A was a more potent inhibitor of histamine-stimulated adenylate cyclase (IC50 of 1.5 X 10(-5) M). 2 In the isolated work-performing heart of the guinea-pig, RMI 12330A (IC50 of 1.1 X 10(-6) M) depressed all cardiac functions: pressures developed, dP/dt, contractile force, dF/dt, work performance and stroke work. Left atrial pressure rose and the positive inotropic response to increasing heart rate (staircase) became negative. Histamine, isoprenaline and ouabain no longer caused positive inotropic effects. 3 Increasing the perfusate calcium concentration from 2.5 mM to 4.5 and 6.5 mM completely restored cardiac function after its depression by RMI 12330A. 4 RMI 12330A uncoupled mitochondrial oxidative phosphorylation; the classical uncoupler, dinitrophenol, had the same effects on cardiac dynamics as RMI 12330A. 5 RMI in high doses inhibited hydrolytic activity of Na+, K+-ATPase of crude and purified heart preparations (IC50 of 1.7 X 10(-4) M) and inhibited ouabain binding to the same enzymes (IC50 of 1.5 X 10(-4) M). 6 A lactam-imine analogue of RMI 12330A that had no effect on adenylate cyclase, was also without effect on any of the systems examined.

Adenylyl Cyclase Inhibitors↗
PubMed1980

Donor pretreatment: rat heart allograft survival and measurement of passenger leukocyte depletion with indium-111.

The present experiment was designed to study the relationship between rat heart allograft survival and passenger leukocyte depletion in donor-pretreated animals. Untreated Lewis rats served as recipients of cardiac allografts from treated Fischer rats. Passenger leukocyte depletion was assayed with indium-111 oxine-labeled leukocytes (predominantly lymphocytes) which were infused into donor rats 6 hr before treatment with cyclophosphamide, antilymphocyte globulin (ALG), sublethal total body irradiation, or in vitro perfusion-preservation of the isolated beating heart. In vivo pretreatment of the donor with cyclophosphamide resulted in a significant prolongation of heart allograft survival but effected no reduction in graft-labeled lymphocytes. In vitro perfusion-preservation of the donor heart, for 1 to 2 hr, led to a 50 to 60% reduction in graft-labeled lymphocytes but failed to significantly prolong the survival of the heart allografts. Both ALG and sublethal total body irradiation donor pretreatments resulted in significant prolongation of heart allograft survival and a 20 to 25% labeled passenger lymphocyte depletion. This study demonstrates that there is no direct correlation between allograft survival and the degree of mobile passenger lymphocyte depletion, suggesting that the efficacy of leukocytotoxic donor pretreatment methods may depend in part on alternative mechanisms.

Animals↗
PubMed1980

[Examination of placenta by light and electron microscope in a woman patient with renal transplant (author's transl)].

The placenta of a woman who had received a renal graft before she became pregnant was examined. The light- and electronmicroscopical results were as follows: 1. Enlargement of the granulated endoplamatic reticulum in the syncytium. 2. Increase of the syncytial knots. 3. Persistence of exceeding numbers of Langhans cells. These alterations coinciding with the immune suppressive therapy might play a role for the initiation of the growth retardation as observed in children of renal-grafted mothers.

Adult↗
PubMed1979

[The amnion epithelium in hydramnion. Light- and electron-microsocpy studies].

Human amniotic epithelium was examined in cases of pregnancy complicated with hydramnios; the light- and electronmicroscopical results were compared with those of epithelium in normal pregnancy. The cells of the hydramniotic epithelium show an increased number of microvilli in apical and lateral cell surfaces. There are also a greater number of desmosomes and enlarged intercellular spaces. In a single case where hydramnios was correlated with maternal diabetes mellitus the amniotic epithelium is characterized by local foci showing cellular dystrophy.

Amnion↗
PubMed1978

Transient kinetics of Ca2+ transport of sarcoplasmic reticulum. A comparison of cardiac and skeletal muscle.

Current evidence supports similar functions and mechanisms for cardiac sarcoplasmic reticulum (CSR) as for skeletal sarcoplasmic reticulum (SSR). It is thought that the slower relaxation rate of cardiac muscle compared to fast skeletal muscle reflects the lower ATPase activity and calcium transport of CSR. Possible quantitative differences is phosphorylation, dephosphorylation, and calcium transport of the isolated preparations are studied using a quench-flow apparatus. The results show that both CSR and SSR bind calcium tightly in the absence of ATP, and coupling of E approximately P formation and calcium transport occurs in the transient phase of ATP hydrolysis. The rate of phosphorylation (t-1/2 - 10 ms) of sarcoplasmic reticulum (SR) preloaded with calcium is the same for cardiac and skeletal preparations. However, the rates of dissociation of extra vesicular calcium (10 s-1 versus 15 s-1), phosphorylation of calcium-free SR, and dephosphorylation of E approximately P (8 s-1 versus 12 s-1) are lower for CSR than for SSR. By computer simulation, the apparent rate constants associated with the reduced rates of phosphorylation of calcium-free SR were: 12 s-1 for CSR and 63 s-1 for SSR in the presence of high Mg2+. The difference in the rates may be partly responsible for the lower levels of ATPase and calcium transport activity with characterize cardiac muscle preparations.

Animals↗
PubMed1978

Rise and fall of cyclic AMP required for onset of lymphocyte DNA synthesis.

The adenosine 3',5'-monophosphate (cyclic AMP) levels of mouse lymphocytes rose and fell sharply 10 hours after stimulation with concanavalin A. Treatment of the cells with indomethacin reversibly prevented the increase in cyclic AMP and the subsequent onset of DNA synthesis. When the heightened cyclic AMP before S phase was maintained by either inhibiting phosphodiesterase or by adding the 8-bromo derivative of cyclic AMP, DNA synthesis was also blocked. Both the increase and decrease in cyclic AMP appear to be required for progression of lymphocytes into the S phase of growth.

4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinone↗
PubMed1978

Increased phosphorylation of a specific protein in mitogen-stimulated lymphocytes.

The phosphorylation of proteins from murine splenic lymphocytes was studied. When the phosphorylation of proteins in extracts from Concanavalin A (ConA)-treated lymphocytes was compared with that of resting lymphocytes, there was only one detectable difference between them. A protein of 135,000 mol. wt was highly phosphorylatable in extracts from ConA-treated cells while phosphate incorporation into this protein was slight in extracts from untreated cells. This effect could be observed 12 h after ConA treatment and was maximal during S phase. This soluble protein was also phosphorylated in intact lymphocytes.

Animals↗
PubMed1978

[Long-term cultures of trophoblast cells and mixed trophoblast cultures as a model for in-vitro studies (author's transl)].

Trophoblast cell-cultures provide a much promising model for qualitative and quantitative in-vitro-examinations of immunological, morphological and biochemical items. In the present paper an attempt has been made to analyze the light-microscopically identificable morphological modifications of the cultured cells under standardized culture-conditions in a temporary order. Furthermore, a number of single cases is presented in which mixed cultures of trophoblast cells with heterologous cells of embryonic origin and with cells derived from adult malignoma were tried.

Cells, Cultured↗