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Biomedical subjects

S Xie

Publications and source records attributed to S Xie.

At least 109 records · Page 6Linked to original sources
PubMed1992

Influence of the embryo on intrauterine migration in sheep.

Mechanisms of intrauterine migration were examined in 55 ewes. In the first experiment, corpora lutea were removed from unilaterally ovariectomized ewes on d 4 (d 0 = estrus) and pregnancy was maintained by giving exogenous progesterone. In Exp. 2, the reproductive tract was altered surgically such that embryos initially entered the uterine horn contralateral to the site of ovulation. In Exp. 3, ewes received beads of silastic polydimethylsiloxane that released either cholesterol or estradiol-17 beta in an attempt to mimic embryonic synthesis of estradiol. In the fourth experiment, unilaterally ovariectomized ewes were superovulated and spacing of embryos within the uterus was then examined. In all experiments, ewes were slaughtered on d 15 and recovery of embryos or beads from each uterine horn indicated that migration had occurred. All ewes in Exp. 1 and 2 that had two conceptuses experienced embryonic migration. Beads impregnated with estradiol migrated farther (P less than .01) than cholesterol-containing beads (27.6 +/- 4.3 vs 12.5 +/- 1.6 cm, respectively). In Exp. 4, only one conceptus had migrated into the contralateral horn in all ewes. These results demonstrated that 1) embryonic migration was not affected by local vs systemic exposure to progesterone, 2) embryos migrated into the unoccupied horn, regardless of the initial horn of entry, 3) estradiol may stimulate embryonic migration, and 4) conceptuses were not equally distributed between horns.

Animals↗
PubMed1992

Plasma 3 alpha, 17 beta-androstanediol glucuronide concentrations in normally menstruating Chinese women.

Hirsutism is rare in oriental women. In order to define the androgen metabolism in these women, plasma levels of androstanediol glucuronide (AG) along with testosterone (T), androstenedione (delta 4A), dehydroepiandrosterone sulfate (DHAS) and sex hormone binding globulin (SHBG) were determined in samples collected from 22 normally menstruating Chinese women. Their ages were 37.7 +/- 7.2 years (mean +/- S. D.) with a range of 27 to 46 years. All were born of Chinese parents. None were on any hormonal medication for at least one year. Compared to our local controls, no significant differences were observed in plasma androgens and SHBG concentrations. Comparable levels of AG, delta 4A and T in these two groups suggest that in Chinese women, under basal conditions, the androgen metabolism is comparable to their north american counterparts.

Adult↗
PubMed1991

Immunoreactive inhibin in follicular fluid is related to meiotic stage of the oocyte during final maturation of the porcine follicle.

The concentration and content of inhibin was determined in individual porcine follicles from gilts ovariectomized at various times after the onset of estrus. In one experiment, gilts (n = 5) were ovariectomized at 0, 10, or 20 hr after the onset of estrus and the follicular fluids from all large follicles individually aspirated. In a second experiment, gilts (n = 6) were ovariectomized at 21, 24, 27, 30, or 34 hr after the onset of estrus; follicular fluids were aspirated; and each oocyte was stained and evaluated for cytogenetic stage of meiotic maturation. Inhibin was determined in diluted follicular fluids with a radioimmunoassay based on a synthetic peptide replica of part of the alpha subunit of porcine inhibin. Inhibin values were expressed in terms of thousands of units (kU) of a World Health Organization inhibin standard (86/690). Concentration of inhibin did not vary among hours (overall mean 248 kU/ml). Total follicular content of inhibin also was not different among hours (overall mean 57 kU/follicle). When follicles were classified on the basis of the maturation of the oocyte, significant differences were found. Concentration of inhibin in follicles with a germinal vesicle-stage oocyte was 138 kU/ml, whereas follicles with more mature oocytes had concentrations of between 204 and 254 kU/ml. Follicular content of inhibin showed a similar pattern with 34.9 kU/follicle at germinal vesicle stage, increasing to 42.5-56.1 kU/follicle at later stages. Quantities of inhibin were also negatively skewed and were positively correlated to follicular content of estradiol and dermatan sulfate.

Animals↗
PubMed1991

[Preliminary study of cervicovaginal peroxidase as indicator for ovulation].

The study was designed to determine whether the change in the pattern of cervicovaginal peroxidase activity in the fertile period of women can serve as a basis for the development of a technique to predict ovulation time in natural family planning. Eight healthy women volunteered for this study in Chengdu area. The samples of cervical mucus and vaginal secretion were collected. The specific G-Px activity was measured with reference to the procedure of Tsibris, et al., on days 6, 8, 10, 12 through 16, 18, 20, 22, 24 of each menstrual cycle; at the same time an antecubital venous blood sample was drawn to be analyzed for levels of LH, FSH, E2, and P by RIA. The data showed that in 7 ovulatory cycles the G-Px activity did not vary regularly in vaginal secretion but it did drop rapidly in cervical mucus 2 or 3 days before ovulation time and it rose again one day after ovulation. The results suggest that the measurement of the G-Px activity in cervical mucus can be used to predict ovulation by two to three days before the time.

Cervix Mucus↗
PubMed1990

Effects of stress on lysability of tumor targets by cytotoxic T cells and tumor necrosis factor.

The effects of stress on four tumor cell lines are analyzed in view of the possibility that stress protects tumor cells against immune attack. We show that stress causes resistance to CTL and TNF in two cell lines. Induction of resistance is time dependent and reversible and not due to failure of killer cells to interact with stressed targets. It is shown that stress induces stress proteins concomitant with induction of resistance to killer cells and TNF. Moreover experiments are presented suggesting that resistance to either immune effector is due to independent mechanisms. The conclusion that stress can induce mechanisms in targets that interfere with the action of TNF as well as with target lysis following a lethal hit by CTL is discussed.

Animals↗
PubMed1990

Limitations of oviductal transfers in swine.

Eighty-six crossbred gilts were used in a series of experiments 1) to determine if eight-cell embryos enter the uterus before four-cell embryos do, and 2) to investigate the effects of transferring older, more developed embryos, either with or without intact zona pellucidae, to the oviducts of swine. Results of these experiments suggested that both four-and eight-cell embryos randomly enter the uterus on Days 3.5 to 4 (Day 0 = onset of estrus). Though there were no differences in survival rates or subsequent morphology of recovered embryos when transferred to the oviduct or uterus on Day 4, the transfer. of Day-6 embryos to the oviduct resulted in lower (P < 0.01) survival rates, and the recovered embryos were smaller (P < 0.01) than those introduced into the uterus. Survival rates were lower (P < 0.06) for zonae-free embryos transferred to the oviduct than for zonae-intact embryos; however, these differences were not evident when zonae-free embryos were transferred into the uterus. These experiments demonstrate that oviductal transfer procedures in swine are limited to zonae-intact, preblastocyst stage embryos.

Journal Article↗
PubMed1990

Changes in follicular endocrinology during final maturation of porcine oocytes.

Thirty-one gilts were ovariectomized between 21 and 34 hr after the onset of estrus to compare changes in follicular endocrinology with stages of oocyte maturation. Oocytes were recovered from 6 to 8 mm follicles and classified by stage of meiosis. Remaining follicular fluid was assayed for steroids and dermatan sulfate. Amounts of prostaglandin F2 alpha (PGF2 alpha) and E2 (PGE2) were measured in intramural tissues. Coincident with germinal vesicle breakdown, the follicular content of all steroids except testosterone decreased (P less than .05). As oocytes approached metaphase II, the amount of progesterone within follicles increased (P less than .05), and estradiol continued to decrease (P less than .05). The pattern of dermatan sulfate content was biphasic and peaked at germinal vesicle breakdown and anaphase stages. Amounts of PGF2 alpha and PGE2 within intramural tissues increased (P less than .05) throughout oocyte maturation. Follicular atresia was evident during estrus; however, more (P less than .05) atretic follicles were recovered at germinal vesicle than metaphase II stages (20 vs 3%, respectively). Follicular development, within a gilt, was skewed (P less than .05) and classification of follicles by hormone content demonstrated that a majority were more mature than a minority of less mature follicles. These data suggest that follicular maturation and oocyte development are highly correlated in swine. Furthermore, partitioning the follicular variability by hour and stage of oocyte maturation allowed for more precise assessment of follicular endocrinology than previously reported.

Androstenedione↗
PubMed1990

Ovulation and early embryogenesis in swine.

Thirty gilts were used to examine if the sequence in which oocytes were released at ovulation contributed to differences in embryonic development and uterine secretions by Day 12 (Day 0 = onset of estrus). Oocytes of follicles destined to ovulate last were recovered 42 h after injecting proestrous gilts with hCG, incubated with a fluorescent stain, and returned to the donor's oviduct. These later-maturing oocytes subsequently became the lesser-developed (p less than 0.01) embryos on Day 4. In a second experiment, lesser- vs. more-developed Day 4 embryos from additional gilts were transferred to ligated uterine horns of nonpregnant gilts. Subsequently, the lesser-developed Day 4 embryos became the smaller (p less than 0.01) blastocysts within a litter on Day 12. Uterine flushings associated with lesser-developed embryos on Day 12 contained less estradiol (p less than 0.01), less total protein (p less than 0.10), and less acid phosphatase activity (p less than 0.05), but total content of calcium was not different compared to flushings that contained more-developed embryos. Analysis of uterine flushings with two-dimensional PAGE procedures indicated advanced uteroferrin-associated glycoprotein secretion from the horn that contained more-developed embryos. Results of these experiments suggested that oocytes of later-ovulating follicles were progenitors of smaller embryos, which probably stimulated uterine secretion later than more advanced littermates on Day 12.

Acid Phosphatase↗
PubMed1990

Relationship between oocyte maturation and fertilization on zygotic diversity in swine.

Two experiments were conducted to examine how oocyte maturation and fertilization influence zygotic diversity in swine. In the first experiment, the distribution of oocyte maturation was compared to that of zygotic development. Oocytes were aspirated from follicles of 31 gilts and classified into stages of meiosis. Zygotes were flushed from oviducts of 19 additional gilts and classified into stages of meiosis and fertilization. The second experiment examined whether the time from ovulation to fertilization was constant among all oocytes. To test this premise, four to six oocytes from follicles of 10 mated gilts were aspirated just before or during ovulation, stained and transferred back into the oviducts of these same gilts. Zygotes were recovered 10 h later to determine whether the first oocytes ovulated were the more developed zygotes and, conversely, whether the last oocytes to be ovulated represented the lesser developed contemporaries. The skewed (P less than .05) distribution of oocyte maturation was similar to that of zygotic development. Regression of the frequency distribution describing early oocyte maturation resulted in a line with a slope (.59) that was similar to the slope (.58) of the regressed distribution of zygotic development. Likewise, the order of ovulation and order of subsequent stages of zygotic development were similar. These data suggest that variation in zygotic development in swine was due to variability in oogenesis; the time from ovulation to fertilization appeared to be constant.

Animals↗
PubMed1990

Effects of intramuscular administration of recombinant bovine interferon-alpha I1 during the period of maternal recognition of pregnancy.

One hundred ewes were utilized to determine the effects of interferon supplementation on the number of ewes pregnant and embryonic survival. Ewes were checked twice daily (0700 and 1600) for estrus using fertile rams. On d 12 through 16, ewes received twice-daily i.m. injections of either recombinant bovine interferon alpha I1 (2 mg IFN) or vehicle. Ewes remained penned with rams and were observed for subsequent estrous activity for at least 35 d after mating. To determine the number of fetuses and corpora lutea, all ewes were subjected to one surgery during mid-pregnancy (d 45 to 80). More (P less than .05) ewes were pregnant after treatment with IFN vs vehicle (45 of 49, 92% vs 37 of 49, 76%, respectively). The interestrous interval for ewes that were treated with IFN and did not conceive was longer (P less than .05) than for ewes given vehicle (26 +/- 1 vs 17 +/- 2 d, respectively). Embryonic survival (98.2 vs 87.9%; P less than .05), calculated as the number of fetuses present at the time of laparotomy and expressed as a percentage of the ovulation rate, and percentage of ewes with 100% fetal survival (96 vs 76%; P less than .05) were greater after treatment with IFN. It was concluded that supplementation of IFN increased both the number of ewes pregnant and embryonic survival.

Animals↗
PubMed1990

[New single point mutation at the initiation codon (ATG-AGG) identified in amplified genomic DNA of a Chinese with beta-thalassaemia].

A new single nucleotide change at nt 2 of exon 1 of the beta-globin gene was identified in a Chinese female patient with beta-thalassaemia. Dot blot hybridization of the amplified genomic DNA with oligonucleotide probes showed that she carried the four base deletions at the codons 41/42. Direct DNA sequencing on the amplified DNA revealed that she also carried a new mutation (ATG-AGG) at the initiation codon on the other beta-globin gene. This single nucleotide change abolishes a NcoI recognition site and hence it can be directly visualized after gel electrophoresis. Analyses of restriction fragment length polymorphisms showed that she also carried a rightward -3.7 kb (type I) deletion in her alpha-globin genes, and is in fact a alpha beta-thalassaemia genotype.

Base Sequence↗
PubMed1990

[Effect of moxibustion on the inflammatory reactions of adjuvant arthritics rats].

Adjuvant arthritic (AA) rats were used as the experimental model and the thickness of pedal pad, the circumference and the pathological (light microscopic changes of the ankle joint as well as the plasma content of middle sized molecules (MSM) were studied before and at subsequent experimental days after moxibustion (once a day for 6 days, on Shenque acupoint). The results showed that moxibustion reduced the inflammatory reactions significantly in comparison with that of the control group.

Animals↗
PubMed1990

Causes and consequences of early embryonic diversity in pigs.

Within 14 h of ovulation, follicular development in gilts was skewed towards a majority of mature follicles, based on their endocrine milieu. Oocyte maturation was also skewed, with a majority of the oocytes being meiotically more developed than the rest. Similarly, the pattern of ovulation in gilts was such that 70% of the follicles ovulated during a short period of time, while most of the remaining 30% ovulated over a more protracted period. This majority/minority pattern of both oocyte development and ovulation paralleled the distribution of development among 1-cell litter-mate embryos. Furthermore, oocytes of follicles predicted to ovulate first became the more developed embryos, while oocytes from later ovulating follicles became the lesser developed embryos. When these later ovulating follicles were destroyed by electrocautery, diversity in embryonic morphology was reduced by Day 12, and this reduction resulted from elimination of the lesser developed embryos. Genetic factors might also affect embryonic disparity, as SLA (swine leucocyte antigen complex) haplotype affected cleavage rates of embryos from miniature pigs. Results of various embryo transfer experiments demonstrated that the more developed embryos within a litter have a competitive advantage for survival over their less developed contemporaries. These lesser developed embryos, however, were just as viable as the more developed embryos after asynchronous transfer to recipients displaying onset of oestrus 1 day after the donors. The more developed embryos within the litter, by synthesizing more oestradiol than the smaller embryos, advanced uterine secretions. As a result, the lesser developed embryos probably became more susceptible to this new environment and eventually died in an asynchronous environment. Therefore, we suggest that early embryonic mortality directly relates to sequences of oocyte and follicular maturation, as oogenesis directs embryogenesis.

Animals↗
PubMed1990

[Degradation of acetonitrile by Acinetobacter sp. 51-2].

A strain of Acinetobacter sp. 51-2 was capable of degrading acetonitrile and utilizing various nitrile compounds, such as propionitrile, butyronitrile, acrylonitrile and so on. The ability and speed of degrading acetonitrile were quite strong and fast. Strain 51-2 could degrade 25 g/L acetonitrile in 48 h by adapted cells. The efficiency of degrading acetonitrile was closely related to the conditions of culturing bacterial cells. The reaction temperature and present metals appeared to have a little effect on degradation of acetonitrile.

Acetonitriles↗
PubMed1990

[Cardiac tumors: clinical and echocardiographic diagnosis of 65 cases].

65 cases of cardiac tumors were diagnosed and studied by echocardiography. Among them 49 were primary tumors including 43 cases of myxoma, one case each of hamartoma, lipomatous infiltration, fibroma, hemangioma, rhabdomyosarcoma, pericardial mesothelioma, and 16 cases of secondary cardiac tumors. It was found that the nature of primary cardiac tumors could be speculated by two-dimensional echocardiography based on their pathological features. Most patients with large left atrial myxoma had obstructive symptoms of mitral valves, abnormal ECG and enlarged left atrium, whereas patients with small atrial myxoma, embolic phenomenon was liable to occur. Echocardiography of secondary cardiac tumors showed that the tumors usually invaded most frequently both the myocardium and pericardium as single or multiple nodular echoes in the myocardium under pericardium or within the pericardial cavity, with profuse pericardial effusion. Occasionally, the secondary tumor appeared as a large mobile intracavitary mass or an extracardiac one compressing the heart or large vessels. It was noticed that cardiac symptoms might be the clinical clue in certain patients with extracardiac primary malignancy.

Adult↗
PubMed1989

Effects of the oviduct and wheat germ agglutinin on enzymatic digestion of porcine zona pellucidae.

Seventy-two crossbred gilts were utilized to examine whether the oviduct rendered zona pellucidae resistant to protease digestion, whether the uterus reversed this resistance and whether such a uterine reversal was necessary for hatching. Oocytes were aspirated from follicles 22 to 28 h after onset of estrus (d 0); oviductal and uterine oocytes or embryos were collected on d 1 to 6. These oocytes and embryos were subjected to a solution containing .1% trypsin and .1% pronase (37 degrees C) for observation of zona pellucidae digestion. Zonae of oviductal oocytes were more (P less than .001) resistant to digestion than were follicular oocytes. Placement of follicular oocytes in oviducts for 30 min rendered zona pellucidae more (P less than .001) resistant to protease digestion than oocytes not exposed to oviductal secretions. Resistance of zona pellucidae to proteases, however, decreased (P less than .001) after entry into the uterus. Zonae of morulae retained in oviducts took longer (P less than .001) to digest than those recovered from the uterus. Blastocysts also were treated with wheat germ agglutinin (WGA; 50 micrograms/ml) for 40 min to determine whether artificial induction of zona resistance to enzymatic digestion affected the ability of embryos to hatch. Though WGA treatment delayed (P less than .001) enzymatic digestion of zona pellucidae, time from collection to hatching was not affected. This experiment indicated that the oviduct delayed enzymatic digestion of the zona pellucidae, whereas the uterus reversed this delay. The re-establishment of enzyme susceptibility after uterine entry, however, appeared to be unrelated to the subsequent ability of blastocysts to hatch.

Animals↗
PubMed1988

Survival of small and large littermate blastocysts in swine after synchronous and asynchronous transfer procedures.

Thirty-two crossbred sows were assigned to synchronous and asynchronous embryo transfer procedures to determine if, within a litter, small blastocysts were as viable as large blastocysts. Synchronous embryo transfers were established when donors and recipients displayed the onset of estrus (Day 0) within 6 h of each other. Asynchronous transfers were established when recipients displayed the onset of estrus 18 to 24 h after that of donors. An equal number (four or five) of the smallest and largest diameter blastocysts, from a Day 7 donor, were transferred to separate uterine horns of a Day 7 (synchronous) or a Day 6 (asynchronous) recipient. Each recipient's uterine horns were ligated at the external bifurcation to prevent transuterine embryonic migration. The percentage of blastocysts surviving was determined 300 h (12.5 d) after donors exhibited estrus. Small as well as large Day 7 blastocysts survived following asynchronos transfer to a Day 6 recipient. However, fewer (P<0.01) small blastocysts survived synchronous transfer than large blastocysts. These data suggested that small blastocysts were lost due to asynchrony with the uterine environment; however, when transferred to a less advanced environment, small blastocysts were equally viable as large blastocysts.

Journal Article↗