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Biomedical subjects

Z M Yang

Publications and source records attributed to Z M Yang.

At least 55 records · Page 3Linked to original sources
PubMed1996

Localization of leukemia inhibitory factor in human endometrium during the menstrual cycle.

Leukemia inhibitory factor (LIF) has been shown to be imperative for the implantation of mouse blastocysts. The objective of this study was to examine the pattern of LIF protein in the human endometrium during the menstrual cycle. A low level of LIF was detected in endometrial glands during the proliferative phase. During the luteal phase, LIF staining in the glands appeared stronger in the mid- and late luteal phase than immediately after ovulation. However, a low level of LIF was detected in the stromal cells during the early and midproliferative phase, while only a minimal level was observed during the late proliferative and luteal phases.

Adult↗
PubMed1995

Leukemia inhibitory factor, LIF receptor, and gp130 in the mouse uterus during early pregnancy.

Leukemia inhibitory factor (LIF) has been shown to play an important role in the implantation of mouse blastocysts. The present study was designed to investigate the changes of LIF protein, LIF receptor, and gp130 in the mouse uterus during the early pregnancy. LIF protein and LIF receptor were at high levels in the mouse uterus near the time of ovulation and on day 4 of pregnancy. gp130 was highest on days 3 and 4 of pregnancy. Both LIF receptor and gp130 showed strong staining in the stroma of the day 5 uterus, at a time when LIF protein was low. The presence of LIF receptor and gp130 in the luminal epithelium on day 4 and in the stroma on day 5 may indicate the site of the high affinity LIF receptor. The coexistence of a high level of LIF protein, LIF receptor, and gp130 in the day 4 uterus is consistent with the previously observed high level of uterine LIF mRNA on the same day and the importance of LIF for the blastocyst implantation in mouse.

Animals↗
PubMed1995

Stimulation of prostaglandin (PG) F2 alpha and PGE2 release by tumour necrosis factor-alpha and interleukin-1 alpha in cultured human luteal phase endometrial cells.

Tumour necrosis factor-alpha (TNF-alpha) and interleukin-1 alpha (IL-1 alpha) are important mediators of cell signalling in the uterus. Prostaglandins (PG) have been implicated in the increase of endometrial vascular permeability which occurs during the implantation process. This study evaluates the effect of these two pleiotropic cytokines on PGF2 alpha and PGE2 release from human luteal phase endometrial glandular epithelial cells (GEC) and stromal cells (STC) in culture. Basal PGF and PGE release did not differ significantly from each other or among cell types, and declined significantly with increasing number of days in culture. On day 3, basal PG release had decreased to half of that on day 1 of culture. However, both cell types were still able to respond to the addition of exogenous arachidonic acid (5 microM) on day 3 of culture, with PG release by GEC being elevated 7- to 10-fold and by STC moderately, but still significantly, on day 4. The permissive effect of arachidonic acid on the stimulation of PG release may indicate the down-regulation of phospholipase A2 with continued time in culture. However, the addition of arachidonic acid (5 microM) on day 0 of culture, while able to cause significantly increased PG release from GEC, had no effect on STC. In contrast, the addition of a combination of arachidonic acid (5 microM), and either recombinant human TNF-alpha (10 micrograms rhTNF-alpha/l) or 10 micrograms rhIL-1 alpha/l, had a synergistic action and caused the significantly increased release of PGF and PGE from both cell types, compared with that achieved with either arachidonic acid or the cytokine alone (although GEC responded more than STC). During the first 24 h after the addition of rhTNF-alpha or rhIL-1 alpha, both cytokines stimulated PG release from both cell types in a dose- and time-dependent fashion. Neither cycloheximide (10 microM) nor actinomycin D (10 microM) affected basal PG release, but both blocked cytokine-induced PG release from both cell types. These results suggest that there is a differential control of human endometrial cell PG biosynthesis, and that PG release may be regulated through gene activation.

Arachidonic Acid↗
PubMed1995

Leukaemia inhibitory factor in human endometrium during the menstrual cycle: cellular origin and action on production of glandular epithelial cell prostaglandin in vitro.

Leukaemia inhibitory factor (LIF) is a pleiotrophic cytokine which plays an obligatory role in mouse implantation. To investigate its potential role in the regulation of uterine function in the human, LIF secretion by isolated human endometrial glandular epithelial and stromal cells in primary culture was determined. Endometrial cells secreted a detectable amount of LIF protein during the first 48 h of culture. In the follicular and late-luteal phases, LIF secretion by both cell types was low. At every stage of the menstrual cycle, the epithelial cells secreted significantly more LIF than did stromal cells. Glandular epithelial cells of the mid-luteal phase, at the expected time of implantation in the human, secreted significantly more LIF than at other stages of the cycle. Stromal cells showed a similar, but nonsignificant, LIF secretion pattern. It could be concluded that endometrial LIF expression was dependent on cell type and stage of the menstrual cycle, and might thus play a role in human implantation. Oestradiol-17 beta stimulated both prostaglandin (PG) F and E release by the epithelial cells in both follicular and luteal phases. PGE release during the luteal phase was greater than in the follicular phase. However, addition of recombinant human LIF did not change either PGF or PGE release in either follicular or luteal phases, in the presence or absence of oestradiol.

Adult↗
PubMed1995

Expression patterns of leukaemia inhibitory factor receptor (LIFR) and the gp130 receptor component in rabbit uterus during early pregnancy.

The presence of leukaemia inhibitory factor (LIF) binding and expression of the gp130 component of the LIF receptor were studied in the rabbit uterus during pregnancy. LIF binding to myometrium was moderate in oestrous and non-oestrous animals and on day 1 of pregnancy, declined on days 2 and 3, and increased to a peak value on days 5 and 6 of pregnancy. Binding to stromal cells was not observed. Binding of LIF to luminal and glandular epithelium was low in unmated animals and on days 1 and 2 of pregnancy. Binding to luminal epithelium increased from day 3, and to glandular epithelium from day 5 of pregnancy. Highest binding was seen on days 5 and 6, with a slight decline observed on day 7, and with little difference between the mesometrial and antimesometrial regions of the implantation site. In all cases, binding of LIF was similar in the uteri of day 6 pseudopregnant and pregnant animals. At all stages, gp130 was absent from stroma and almost absent from myometrium and glandular epithelium. It was expressed in luminal epithelium, reaching maximal expression on day 6 of pregnancy and pseudopregnancy, but diminished on day 7 of pregnancy, particularly in the antimesometrial area of the implantation site. The coexpression of LIF binding and gp130 may indicate the presence of high-affinity LIF receptor, which matches the pattern of LIF protein expression and, as in mice, suggests its importance for implantation.

Animals↗
PubMed1995

Interleukin-1 alpha in the rabbit uterus during early pregnancy.

Immunoreactive (ir) interleukin-1 alpha (IL-alpha) was present in the endometrium and myometrium of the rabbit uterus during early pregnancy. Interleukin-1 alpha was at a high level in endometrial epithelium from days 3 to 6 of pregnancy. A similar level of IL-1 alpha was detected on day 6 of pseudopregnancy. Interleukin-1 alpha declined rapidly on day 7 at both the implantation and non-implantation areas. Our results suggest that IL-1 alpha may play a role in rabbit blastocyst implantation.

Animals↗
PubMed1994

Temporal and spatial expression of leukemia inhibitory factor in rabbit uterus during early pregnancy.

Leukemia inhibitory factor (LIF) has been shown to play an important role in the implantation of mouse blastocysts. The present study was designed to document the appearance of LIF in the rabbit uterus during early pregnancy and to determine whether changes just prior to implantation, similar to those in mice, occurred. LIF was localized in endometrial epithelium, myometrium, and endometrial glands. A low level of LIF was detected in the uterus of nonestrous and estrous females. LIF expression reached its highest level on day 5 of pregnancy and declined on days 6 and 7. By day 13 of pregnancy, little endometrial LIF was apparent. The expression of LIF on day 5 of pseudopregnancy was similar to that on day 5 of pregnancy. LIF expression was much higher at implantation sites than that at nonimplantation areas on day 7 of pregnancy. It is concluded that LIF may be important for the implantation of rabbit blastocysts.

Animals↗
PubMed1992

Abnormalities of ion-exchange proteins of the red cell membrane in iron deficiency anemia.

The influences of iron deficiency on erythrocyte spanning membrane proteins, band 3 protein and Na(+)-K(+)-ATPase, were studied in the growing rats with iron deficient anemia. The main findings were (1) reduction of band 3 and increment of band 4.1 protein. (2) diminished rate constant of pyruvate-chloride exchange (Kp:Cl.h-1) of the erythrocytes and (3) significant decrease of Na(+)-K(+)-ATPase activity only at the early stage of iron exhaustion. In addition, there was a significant negative correlation between Kp:Cl.h-1 and Na(+)-K(+)-ATPase activity both in iron deficient rats and in the controls. It is suggested that the composition and function of the erythrocyte spanning-membrane proteins for ion exchange could be affected by iron deficiency.

Anemia, Hypochromic↗
PubMed1991

Biochemical modulation of 5-bromo-2'-deoxyuridine and 5-iodo-2'-deoxyuridine incorporation into DNA in VX2 tumor-bearing rabbits.

The thymidine analogues 5-bromo-2'-deoxyuridine (Brd-Urd) and 5-iodo-2'-deoxyuridine (IdUrd) compete with thymidine for incorporation into the DNA of replicating cells. This incorporation results in radiosensitizing effects which are directly related to the degree of analogue substitution. In vitro and in vivo evidence suggests that preadministration or coadministration of the thymidylate synthetase inhibitors fluorouracil and 5-fluoro-2'-deoxyuridine (FdUrd) can modulate analogue incorporation into DNA. We have evaluated in the rabbit VX2 tumor model the effects of thymidylate synthetase inhibitor (fluorouracil or FdUrd) coadministration (as 24-hour, intravenous infusions) on the incorporation of BrdUrd or IdUrd into the DNA of relevant normal tissues (bone marrow, gut mucosa) and intrahepatic VX2 tumor. Tissues were harvested and processed for gas chromatography-mass spectrometry analysis of the thymine, 5-bromouracil, and 5-iodouracil contents in hydrolyzed DNA. Coadministration of FdUrd resulted in statistically significant (P less than .01) enhancement of IdUrd incorporation into the DNA of intrahepatic VX2 tumor and normal (bone marrow and duodenal mucosa) rabbit tissues. Coadministered fluorouracil, on the other hand, significantly enhanced IdUrd incorporation only into DNA of intrahepatic VX2 tumor. Statistically significant enhancement of BrdUrd incorporation was achieved only with FdUrd coadministration and then only into the DNA of intrahepatic VX2 tumor. The percent of thymine replaced by analogue (I) is related to the steady-state arterial plasma drug concentration (C) by the Michaelis-Menten equation: I = I(MAX.) C/(C50 + C). The primary effect of FdUrd coadministration on BrdUrd incorporation into VX2 tumor DNA was a reduction of the C50 parameter (plasma BrdUrd concentration eliciting I = I(MAX)/2) from 8.17 microM to 1.78 microM. On the other hand, the I(MAX) parameter (I as C approaches infinity) was only slightly affected (29.7% to 25.2%). Thus, the degree to which the modulator enhanced analogue incorporation varied inversely with the analogue's steady-state plasma concentration. These results, which describe potential tissue specificity of modulator efficacy and characterize the effects of thymidylate synthetase inhibitor modulation on thymidine analogue incorporation pharmacodynamics, should provide guidance as to dose scheduling of BrdUrd and IdUrd in clinical trials for improved tumor specificity of uptake.

Animals↗
PubMed1991

The superoperonal organization of genes for pigment biosynthesis and reaction center proteins is a conserved feature in Rhodobacter capsulatus: analysis of overlapping bchB and puhA transcripts.

Most of the essential biosynthetic and structural genes involved in bacterial photosynthesis are clustered in a 46 kb region of the Rhodobacter capsulatus genome. Previous analyses have demonstrated that the puf operon, which encodes light harvesting and reaction center structural genes as well as a regulatory gene for bacteriochlorophyll biosynthesis, is expressed from a complex set of overlapping transcripts. Differential initiation and processing of these transcripts is thought to be involved in regulating expression of puf-encoded genes. In this study we demonstrate that the puh operon, which is located 39 kb away from the puf operon, also contains overlapping transcripts. One large 11 kb puhA transcript is shown to be a product of read-through from an upstream operon (bchB) which encodes numerous bacteriochlorophyll biosynthesis genes. A second 1.1 kb mRNA is shown to be derived from the 11 kb bchB transcript by processing and a third, highly expressed, 0.95 kb transcript is shown to be initiated from a promoter located within the distal gene of the bchB operon. The occurrence of overlapping transcripts for the puf and puh operons was further shown to influence development of the photochemical apparatus during conditions of environmental shifts in oxygen tension. Evidence for the occurrence of a "superoperonal" organization of overlapping operons in several different species of purple photosynthetic bacteria is discussed.

Amino Acid Sequence↗
PubMed1991

[Effects of berberine on synthesis of platelet TXA2 and plasma PGI2 in rabbits].

Using radioimmunoassay, we found that berberine (0.50 mol.L-1) inhibited dose-dependently collagen-, ADP-, and arachidonic acid (AA)-induced TXA2 release from platelets. Berberine (25 mg.kg-1) iv lowered rabbit plasma level of PGI2 from 0.92 +/- 0.20 to 0.61 +/- 0.08 ng.ml-1 after 60 min. The results suggest that berberine inhibits AA release from cell membrane phospholipids and its metabolism.

6-Ketoprostaglandin F1 alpha↗
PubMed1990

Rhodobacter capsulatus genes involved in early steps of the bacteriochlorophyll biosynthetic pathway.

Three open reading frames in the Rhodobacter capsulatus photosynthesis gene cluster, designated F0, F108, and F1025, were disrupted by site-directed mutagenesis. Mutants bearing insertions in these reading frames were defective in converting protoporphyrin IX to magnesium-protoporphyrin monomethyl ester, protochlorophyllide to chlorophyllide a, and magnesium-protoporphyrin monomethyl ester to protochlorophyllide, respectively. These results demonstrate that the genes examined most likely encode enzyme subunits that catalyze steps common to plant and bacterial tetrapyrrole photopigment biosynthetic pathways. The open reading frames were found to be part of a large 11-kilobase operon that encodes numerous genes involved in early steps of the bacteriochlorophyll a biosynthetic pathway.

Amino Acid Sequence↗
PubMed1990

Omental autotransplantation in treatment of thromboangiitis obliterans.

From 1981 to 1985, omental autotransplantation was performed for 28 patients with thromboangiitis obliterans on the left lower extremities in 16 patients, the right ones 11, and the right upper limb 1. The early results in all patients were satisfactory. In 19 patients followed up from 1 to 4 years, the results were encouraging, with the improvement of symptoms after operation. In 18 patients, digital ulcers healed within 2-4 weeks. Doppler and electrical impedance plethysmography examinations showed the blood circulation of affected extremities was markedly improved in the 18 patients except one who had the recurrence of digital ulcer 2 years later. In one of the 19 patients the disease recurred one month after the operation, and a lumbar sympathectomy was performed. The indications, the operative technique, and the mechanism of this operation are discussed.

Adult↗
PubMed1989

A simplified method for the preparation of WGA-Sepharose 4B and its use in the purification of MN blood group antigens.

A simplified method for the preparation of wheat germ agglutinin(WGA)-Sepharose 4B by coupling highly purified WGA, prepared by improved affinity chromatography, with BrCN activated Sepharose 4B in a solution of high carbonate buffer is described. The amount of WGA linked to Sepharose 4B was 82.40% (3.07 mg WGA per ml Sepharose 4B). MN blood group antigens of human erythrocyte membranes purified with WGA-Sepharose 4B affinity chromatography showed a single band on sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS/PAGE). The yield of the antigens from 400 mL fresh blood was 32-40 mg. The WGA-Sepharose 4B column could be used several times without loss of activity.

Electrophoresis, Polyacrylamide Gel↗
PubMed1989

5-Bromo-2'-deoxyuridine incorporation into DNA in hepatic VX2 tumor-bearing rabbits.

The halogenated pyrimidine 5-bromo-2'-deoxyuridine (BrdUrd) possesses both radiosensitizing and antimetabolite effects through its incorporation as a thymidine analog in replicating DNA. To evaluate the regional advantage for treatment of hepatic malignancy by hepatic arterial infusion, BrdUrd was infused into either the hepatic artery (HA) or a central vein (iv) in 26 rabbits with intrahepatic VX2 tumor. After a 24-hr constant rate infusion of 10, 20, or 40 mg/kg/24 hr, the percentage BrdUrd incorporation into the DNA of bone marrow, duodenal mucosa, liver, and hepatic VX2 tumor was measured by gas chromatography/mass spectrometry methods. VX2 tumor BrdUrd incorporation was greater by HA than by iv routes (P less than 0.001). At doses of 10 and 20 mg/kg/day, HA to iv BrdUrd incorporation ratios for VX2 tumor significantly exceeded those for bone marrow and duodenum (P less than 0.05). At appropriate dose rates, hepatic arterial administration of BrdUrd provides a regional advantage for DNA BrdUrd incorporation in the rabbit intrahepatic VX2 tumor.

Animals↗
PubMed1989

[Information system of leprosy and its developing tool].

This paper reported briefly composition of leprosy information system and its developing tool (CAMSLEP) with recommendation of distinguishing features. It was developed with Pascal. The software finished is for APPLEII and its compatible microcomputer. An IPF form translates the situations of patient with leprosy into the codes which can be read by microcomputer. The data of patients are saved on diskettes with text of characters in tightened pattern. The software includes five programs which are of "Fill in IPF", "Fill in report", "Designer", etc. "Menu" is available for operating, and "conversation" for input and output. All programs are managed by the general "Menu". In response to this prompt letter in "Menu" you can find your way around in different levels of the operating system for different functions. The way to operate is simple and convenient. It's possible to set up a data-base of patients which can be operated for inserting, deleting, updating and inputting follow-up, outputting 2-dimensional or 3-dimensional report of statistical analysis of multiple factors and to set up a specific information system according to user's requirements with the software.

Humans↗
PubMed1989

[Ameliorative catalytic model of age-specific prevalence of leprosy simulated by using microcomputer].

This paper advances an ameliorative catalytic model to imitate age-specific prevalence rates for leprosy by using microcomputer for eight prefectures in Jiangsu province with analyses of results. The author considers that the distribution of age-specific prevalence of leprosy tallies with the ameliorative catalytic model. It is a curve of S shape which slowly goes up at beginning then faster rising and reaching a plateau after the point of peak. The curve is reflected in characteristics with a longer latent period, longer course of the disease and lower incidence. Through analysing and comparing the practical leprosy prevalence in eight prefectures with three parameters of the catalytic model, it is obviously that the prevalence was positive correlation with parameter a and negative correlation to parameter b, k. Therefore parameters--a, b, k in the two-stage catalytic model respectively represents the force of infection, the speed of eliminating the disease and an indicator of the effect of control disease. Catalytic models may be used to simulate and analyse the disease data in various periods, regions or masses for comprehensive evaluation of the force of infection, ability to eliminating disease in a population and the effect of control programme.

Adolescent↗