Tissue-specific ontogenic expression of prostaglandin H synthase 2 in the ovine myometrium, endometrium, and placenta during late gestation and at spontaneous term labor

OBJECTIVE

The purposes of this study were to determine (1) whether uterine tissues as well as the fetal placenta are involved in the development of prostaglandin-synthesizing capacity associated with impending labor in pregnant sheep and (2) whether the key enzyme of prostaglandin synthesis, prostaglandin H synthase 2, is differentially expressed in the different intrauterine tissues during late gestation and in association with labor.

STUDY DESIGN

Myometrium, endometrium, and fetal placenta were removed from ewes at 95 days' gestation, (n = 3), 101 to 110 days' gestation (n = 3), 111 to 120 days' gestation (n = 3), 121 to 130 days' gestation (n = 3), 131 to 140 days' gestation (n = 3), and 141 to 145 days' gestation (n = 4) and from ewes in spontaneous term labor at 143 to 147 days' gestation (n = 4). Expressions of prostaglandin H synthase 2 messenger ribonucleic acid and protein were determined by Northern blot and Western blot analyses. Prostaglandin H synthase 2 was localized in the fetal placenta by immunohistochemical means.

RESULTS

Levels of both prostaglandin H synthase 2 messenger ribonucleic acid and protein increased gradually from 115 days' gestation in the fetal placenta and from 131 days' gestation in the endometrium. A further and more significant increase in prostaglandin H synthase 2 concentration occurred in the placenta and endometrium during spontaneous term labor. In contrast, myometrial concentrations of prostaglandin H synthase 2 messenger ribonucleic acid and protein remained at steady basal levels during the course of pregnancy and increased only during labor. Prostaglandin H synthase 2 was localized in the trophoblast cells of the fetal placenta.

CONCLUSIONS

Tissue-specific ontogenic expression of prostaglandin H synthase 2 was observed in myometrium, endometrium, and placenta during late ovine gestation and spontaneous term labor. Fetal placenta and endometrium showed increased expression of prostaglandin H synthase 2 messenger ribonucleic acid and protein during late ovine gestation, whereas myometrial prostaglandin H synthase 2 concentration remained low throughout late gestation. Prostaglandin H synthase 2 concentrations in the myometrium, endometrium, and placenta are all upwardly regulated during labor.

A patch clamp study on reconstituted calcium permeable channels of human sperm plasma membranes

Ionic flux is thought to be important in the initiating process of gamete interaction such as acrosome reaction. However, modern electrophysiological methods, intracellular recording and patch-clamping, are difficult to approach the ion channels in mammal sperm membrane of an intact sperm due to its small size. In this work, by reconstituting the channel protein into lipid bilayer, Ca2+ channels in human spermatozoa were investigated with voltage clamp technique. Membrane proteins isolated from human sperm of 12 healthy donors were incorporated into lipid bilayer via fusion. In a cis 50//trans 10 mmol/L CaCl2 solution system, two types of channel events with similar reversal potential near the value of a perfect Ca2+ electrode, and sensitive to nifedipine and verapamil, were observed. Their unit conductance was 40 and 25 pS respectively. Percentage of channel open time was not dependent to holding potential for the former. However, for the channels of 25 pS, the percentage increased when the holding potential was changed from -20 to 100 mV. Ca(2+)-permeable channels were also detected from the spermatozoon samples of two infertile donors. Abnormal open time of these channels indicates that there are some defects in the conformation of the channel protein of infertile sperm membrane.

Dietary 18:3n-3 and 22:6n-3 as sources of 22:6n-3 accretion in neonatal baboon brain and associated organs

The bioequivalence of dietary linolenic acid (LNA) and docosahexaenoic acid (DHA) for brain DHA accretion was measured in neonatal baboons at 4-6 wk of age using stable isotope tracers. Neonates consumed a conventional U.S. term-infant formula devoid of long chain polyunsaturates and with an n-6/n-3 ratio of about 10:1. At 4 wk of age, neonates were dosed with either 13C LNA or 13C DHA. At 6 wk of age, neonate brain, retina, and other organs were harvested for fatty acid and isotopic analyses. The relative accretion of labeled DHA was 7-fold greater as a percentage of dose for the DHA-dosed animals compared to the LNA-dosed animals. The baboon is an omnivore that regularly consumes meat and insects; its plasma lipid profile responds similarly to humans in response to changes in feeding and living habits. These observations suggest that the baboon is a suitable model for human unsaturated fatty acid studies.

Effects of allitridi on intracellular Ca2+ concentration in isolated rat brain cells

AIM

To study actions of allitridi extracted from garlic on intracellular calcium in isolated rat brain cells.

METHODS

Brain cells were isolated from newborn rat brain with Fura 2-AM measurements of intracellular Ca2+ concentration ([Ca2+]i).

RESULTS

Allitridi 1-100 mumol.L-1 concentration-dependently blocked increases of [Ca2+]i caused by potassium chloride and sodium glutamate (Glu) with IC50 of 59.7 and 69.9 mumol.L-1 respectively. Allitridi 100 mumol.L-1 blocked norepinephrine (Nor)-induced [Ca2+]i elevation.

CONCLUSION

Allitridi is an effective agent for blocking the [Ca2+]i increase caused by potassium chloride, Nor and Glu.

Suppression subtractive hybridization identified a marked increase in thrombospondin-1 associated with parturition in pregnant sheep myometrium

Changes in several extracellular matrix proteins, such as fibronectin in fetal membrane and cervical collagens, occur at term and preterm delivery. However, no studies have evaluated changes in extracellular matrix proteins, in relation to myometrial activation recorded using invasive techniques during parturition in any species. We used suppression subtractive hybridization (SSH), to demonstrate the dramatic increases in one extracellular matrix protein, thrombospondin-1 (TSP1), in the pregnant ovine myometrium associated with parturition. Myometrial poly-A- RNA, extracted from term control ewes not in labor at 143-147 days of gestational age (dGA, n = 4), and from ewes in spontaneous term labor (STL) at 145-147 dGA (n 4), was subjected to SSH to construct a subtracted myometrial complementary DNA library. A complementary DNA clone from myometrial subtracted library, representing differentially expressed gene in the pregnant sheep myometrium during STL, was identified as TSP1 by sequence analysis and Blastn search. This cloned TSP1 was used to perform Northern blot analysis on total RNA isolated from five early controls, not in labor, at 130 dGA, five pregnant ewes in betamethasone-induced premature labor (BPL) at 130 dGA (betamethasone administered i.v. to the fetus at 0.48 mg over 48 h), six term-control-not-in-labor ewes at 143-147 dGA, and six pregnant ewes in STL. Northern blot analysis demonstrated that TSP1 increased significantly, associated with both BPL and STL. TSP1 protein level paralleled the increase of TSP1 messenger RNA during BPL and STL. To determine whether increase in this gene paralleled the increased strength of myometrial contractility, six ewes were treated with nimesulide, a selective PG synthase 2 inhibitor, at 147-148 dGA. Nimesulide infusion to the ewe i.v. to inhibit myometrial contraction (30 mg bolus, followed by 5 h infusion, 30 mg/h) commenced 9 h after onset of labor at 147-148 dGA. TSP1 in the myometrium decreased when myometrial contraction was inhibited by nimesulide. Both in situ hybridization and immunocytochemistry demonstrated that fibroblasts and the smooth muscle cells contained TSP1 messenger RNA and protein. TSP1 was also localized in the extracellular matrix. Our conclusions are: 1) our data provide the first evidence that changes in TSP1 are associated with myometrial activation in pregnant sheep during term and preterm labor; 2) myometrial fibroblasts and the smooth muscle cells are responsible for producing TSP1; and 3) SSH is a powerful technique that enables us to study differentially regulated genes during labor.

Differential effects of natural and synthetic glucocorticoids on cytochrome 17alpha-hydroxylase (P-45017alpha) and cytochrome P-450 side-chain cleavage (P-450scc) messenger ribonucleic acid in the sheep placenta

OBJECTIVE

Our purpose was to determine differential effects of natural and synthetic glucocorticoids on cytochrome 17alpha-hydroxylase and cytochrome P-450 side-chain cleavage messenger ribonucleic acid in the sheep placenta and to determine whether feed-forward effects during labor are involved in further inducing placental cytochrome 17alpha-hydroxylase.

STUDY DESIGN

Sheep underwent placement of myometrial electromyogram electrodes while they were under general anesthesia at 117 days' gestation. At 125 days' gestation either saline solution (early control animals not in labor, n = 5), 0.48 mg betamethasone during 48 hours (n = 7), 0.48 mg dexamethasone during 48 hours (n = 7), or 55 mg cortisol during a maximum of 96 hours (n = 4) was directly administered intravenously to the fetus. Necropsies were performed at 127 to 129 days' gestation. We also studied 6 ewes in spontaneous term labor at 143-147 days' gestation, 6 term control animals not in labor at 140 to 147 days' gestation, and 6 sheep in which myometrial activity was inhibited by intravenous infusion to the ewe of the selective cyclooxygenase 2 inhibitor nimesulide 9 hours after the onset of labor beginning at 147 to 148 days' gestation. Total fetal placental ribonucleic acid was analyzed by Northern blot with complementary deoxyribonucleic acid probes for cytochrome 17alpha-hydroxylase, cytochrome P-450 side-chain cleavage, and 18S ribosomal ribonucleic acid to correct for loading.

RESULTS

Placental cytochrome 17alpha-hydroxylase messenger ribonucleic acid was detectable neither in term control animals not in labor nor in early control animals not in labor. Placental cytochrome 17alpha-hydroxylase messenger ribonucleic acid was induced in spontaneous term labor and all cortisol-infused sheep in labor with respect to term control animals not in labor and early control animals not in labor (P <.01). All betamethasone-infused sheep had myometrial contraction activity; however, only 4 of 7 had detectable placental cytochrome 17alpha-hydroxylase messenger ribonucleic acid. Placental cytochrome 17alpha-hydroxylase messenger ribonucleic acid was not detected in dexamethasone-infused sheep, even the 2 that had myometrial contractions. After reversal of the progression of spontaneous labor with nimesulide placental cytochrome 17alpha-hydroxylase messenger ribonucleic acid was significantly lower than the spontaneous term labor group (without nimesulide treatment). The placentas from all animals expressed cytochrome P-450 side-chain cleavage messenger ribonucleic acid, but no changes were associated with either gestational age studied (130 versus > 140 days' gestation) or glucocorticoid-induced premature labor and spontaneous term labor.

CONCLUSIONS

(1) In sheep the expression of placental cytochrome 17alpha-hydroxylase is tightly associated with spontaneous term labor, and active synthesis of placental cytochrome 17alpha-hydroxylase is required during the progression of labor. (2) Cortisol is a more potent stimulator of placental cytochrome 17alpha-hydroxylase messenger ribonucleic acid in sheep than are synthetic glucocorticoids. (3) Betamethasone has a greater effect in inducing labor in sheep than does dexamethasone, possibly mediated through placental cytochrome 17alpha-hydroxylase.

Changes in prostacyclin synthase in pregnant sheep myometrium, endometrium, and placenta at spontaneous term labor and regulation by estradiol and progesterone

OBJECTIVE

Our purpose was to investigate, first, whether there were changes in the abundance of prostacyclin synthase protein in intrauterine tissues of pregnant ewes in association with spontaneous term labor. Second, we examined the effect of either estradiol or progesterone, or both, on regulation of prostacyclin synthase protein abundance in uterine tissues using an ovariectomized nonpregnant sheep model.

STUDY DESIGN

The abundance of prostacyclin synthase protein was quantified by Western blot analysis in the myometrium, endometrium, and placenta of pregnant ewes in spontaneous term labor (n = 6) and term control ewes not in labor (n = 6). The changes of prostacyclin synthase in the myometrium and endometrium of 20 ovariectomized nonpregnant sheep (n = 5 for each group) were evaluated after treatment with estradiol, progesterone, or both.

RESULTS

Prostacyclin synthase protein was present in pregnant and nonpregnant sheep myometrium, endometrium, and placenta at a molecular weight of about 55 kd. At spontaneous term labor the level of prostacyclin synthase decreased in endometrium (P <.05), increased in myometrium (P <.05), and remained unchanged in placenta. Estradiol and progesterone had no effect on prostacyclin synthase protein abundance in nonpregnant ovine endometrium and myometrium.

CONCLUSIONS

The decrease in prostacyclin synthase in pregnant sheep endometrium during labor may indicate paracrine interactions between the endometrium, the myometrium, fetal membranes, or a combination of these. The significant increase of prostacyclin synthase in pregnant sheep myometrium at spontaneous term labor may contribute to the increased uterine sensitivity to oxytocin or stimulate vasodilatation during labor to increase myometrial blood flow. Neither estradiol nor progesterone at the dosages studied changed prostacyclin synthase expression in the nonpregnant myometrium and endometrium. The molecular mechanism or mechanisms that differentially regulate prostacyclin synthase expression in pregnant uterine tissues merit further study.

Bioequivalence of dietary alpha-linolenic and docosahexaenoic acids as sources of docosahexaenoate accretion in brain and associated organs of neonatal baboons

The dietary bioequivalence of alpha-linolenic (LNA) and docosahexaenoic acids (DHA) as substrates for brain and retinal n-3 fatty acid accretion during the brain growth spurt is reported for neonatal baboons who consumed a long-chain-polyunsaturate free commercial human infant formula with a n-6/n-3 ratio of 10:1. Neonates received oral doses of 13C-labeled fatty acids (LNA*) or (DHA*) at 4 wk of age, and at 6 wk brain (occipital cortex), retina, retinal pigment epithelium, liver, erythrocytes, and plasma were analyzed. In the brain, 1.71% of the preformed DHA* dose was detected, whereas 0.23% of the LNA* dose was detected as DHA*, indicating that preformed DHA is 7-fold more effective than LNA-derived DHA as a source for DHA accretion. In LNA*-dosed animals, DHA* was greater than 60% of labeled fatty acids in all tissues except erythrocytes, where docosapentaenoic acid was 55%. Estimates using dietary LNA levels as tracees indicate that brain turnover of DHA is less than 5% per week between weeks 4 and 6 of life. For retina and retinal pigment epithelium, preformed DHA was at levels 12-fold and 15-fold greater than LNA-derived DHA. Liver, plasma, and erythrocytes ratios were 27, 29, and 51, respectively, showing that these pools do not parallel tissue metabolism of a single dose of omega-3 fatty acids. The distributions of labeled fatty acids for LNA*-dosed animals were similar, in the order DHA > DPA > EPA > LNA, except for erythrocytes where docosapentaenoic acid predominated. These are the first direct measurements of the bioequivalence of DHA and LNA in neonatal primate brain and associated tissues.

Succinylated collagen crosslinked by thermal treatment for coating vascular prostheses

Vascular prostheses coated with collagen carefully prepared to avoid contamination were tested to see if it could induce endothelial cell lining throughout the graft surface in a natural way. The collagen fibers were succinylated. Hydrogel produced with the succinylated collagen was used for the sealant to reduce the amount of solid substance. To avoid contamination and the side effects of chemical reagents, the collagen thermally crosslinked under sterile conditions. A suspension of the collagen fibers was enmeshed in the interstices of Dacron fibers of fabric prostheses, which were then thermally crosslinked at 130 degrees C for 20 h. The prostheses were porous when the collagen fiber network was dry. Under wet conditions, however, the water permeability of the grafts was reduced to 0.1 ml/min from the 1,250 ml/min of the original prostheses. Three weeks after implantation in the abdominal aortas of dogs, 81.2 +/- 11% of the luminal surface was macroscopically thrombus free, and 56 +/- 14% was endothelialized. More than 95% of the coated collagen had been absorbed. Numerous fibroblasts had migrated into the graft walls, and capillary blood vessels had infiltrated the inside of the graft walls without foreign body reaction. In the controls, thrombus free areas averaged 9.0 +/- 5%, and endothelialized areas averaged 5.2 +/- 4%. Many giant cells, plasma cells, and lymphocytes had migrated into the graft walls, but no fibroblasts. These results suggest that rapid endothelialization is possible when clean collagen is used.

Ion-channels reconstituted into lipid bilayer from human sperm plasma membrane

Ion environment and ionic fluxes through membrane are thought to be important in the spermatozoa's maturation, capacitation, and the initiating process of gamete interaction. In this work, the membrane proteins isolated from human sperm plasma membrane were reconstituted into planar lipid bilayers via fusion, and the ion channels activities were observed under voltage clamp mode. In cis 200//trans 100 mM KCl solution, a TEA-sensitive cation-selective channel with a unit conductance of 40 pS was recorded. In a gradient of 200//100 mM NaCl solutions, a Na(+)-selective channel with a unit conductance of 26 pS was recorded. In both cases, reversal potential was about-18 mV, which is close to the predicated value of a perfect Nernst K+ or Na+ electrode. In 50//10 mM CaCl2 solution, a cation channel activity with a unit conductance of 40 pS and reversal potential of about -20 mV was usually observed. In 200//100 mM NMDG(N-methyl-D-glucamine)-Cl solution, where the cation ions were substituted with NMDG, a 30-pS anion-selective channel activity was also detected. The variety in the types of ion channels observed in human spermatozoa plasma membrane suggests that ion channels may play a range of different roles in sperm physiology and gamete interaction.

Inhibition of prostaglandin production by nimesulide is accompanied by changes in expression of the cassette of uterine labor-related genes in pregnant sheep

The present study was designed to characterize effects of inhibiting PG production by infusing nimesulide (CAS 51803-78-2) on PGE2 production and expression of uterine labor-related genes in pregnant sheep. Myometrium, endometrium, and placenta were collected following 6 h of i.v. nimesulide or vehicle infusion. Infusions were commenced 9 h after onset of spontaneous term labor. Tissues were also collected from term control ewes not in labor. PGE2 was measured in fetal plasma by RIA. ER, OTR, Hsp 70 and 90, cPLA2, and PGHS-2 messenger RNA (mRNA) abundance in myometrium, endometrium, and PGHS-2 in placenta were quantified by Northern blot analysis. Fetal plasma PGE2 decreased during nimesulide infusion (P < 0.05). ER, OTR, Hsp 70, and Hsp 90 mRNA increased during spontaneous term labor in vehicle infused ewes in both myometrium and endometrium. In myometrium after nimesulide infusion, OTR and Hsp 70 mRNA decreased significantly (P < 0.05) compared with vehicle infused animals, but the decrease in Hsp 90 and ER mRNA fell outside the level of significance. In the endometrium, nimesulide produced a decrease in ER and OTR mRNA (P < 0.05) compared with vehicle infused animals, but the changes in Hsp 90 and 70 mRNA fell outside the level of significance. Nimesulide reversed the up-regulation of PGHS-2 mRNA that occurred in myometrium, endometrium, and placenta during vehicle infusion (P < 0.05). cPLA2 was only elevated in the endometrium in vehicle infused ewes and did not change in either endometrium or myometrium after nimesulide infusion.

CONCLUSIONS

Inhibition of PG production resulted in decreased fetal plasma PGE2. The decreased abundance of mRNA for several of the well described cassette of utero-placental labor-related genes following nimesulide inhibition may result from altered PG production.

[Ion channels of mammalian and human sperm membrane]

Ionic fluxes are thought to be important for sperm physiology. In recent years, using artificial membrane reconstitution and voltage clamp technique, different populations of ion channels, including K+, Na+, Ca2+ and Cl- channel, in mammalian and human sperm membrane were investigated. These studies shed lights to the understanding of some ionic basis underlying some mechanisms of sperm maturation, capacitation and gamete interaction. The results on human sperm ion channels also give us a chance to take it into clinic utility.

Regulation of prostaglandin endoperoxide H synthase 1 and 2 by estradiol and progesterone in nonpregnant ovine myometrium and endometrium in vivo

PG endoperoxide H synthase-2 (PGHS-2) messenger RNA (mRNA) and protein levels are increased dramatically in ovine myometrium and endometrium during both glucocorticoid-induced premature labor and spontaneous term labor. In this study, we examined estradiol and progesterone regulation in vivo of PGHS-1 and PGHS-2 expression at both mRNA and protein levels using a nonpregnant ovariectomized sheep model. We determined the differential distribution of PGHS-2 and PGHS-1 in ovine myometrium and endometrium with immunocytochemistry. Twenty ovariectomized ewes were treated with saline (n = 5) or estradiol infused i.v. for 2 days (50 microg/day; n = 5) or an intravaginal progesterone sponge for 10 days (containing 0.3 g progesterone; n = 5) or an intravaginal progesterone sponge for 10 days with estradiol (50 microg/day) administered on days 9 and 10 with the progesterone sponge still in place (EP; n = 5). PGHS-1 and -2 mRNA and protein were measured by Northern and Western blot analyses, respectively. PGHS-2 mRNA and protein abundance increased significantly in myometrium after estradiol treatment (P < 0.01). In contrast, progesterone was a more potent stimulator than estradiol of PGHS-2 protein abundance in endometrium (P < 0.01). PGHS-1 concentration did not change after estradiol and/or progesterone administration (P > 0.05). PGHS-2 was immunolocalized in myometrial cells and endometrial glandular epithelial cells, whereas immunoreactive PGHS-1 was located in the myometrial cells, endothelial and smooth muscle cells of blood vessels, as well as epithelial cells of glands and stromal cells in endometrium. Estradiol-dependent activation of PGHS-2 gene expression resulted in increased PGHS-2 levels in sheep myometrium in vivo. Progesterone did not have any effect on PGHS-2 gene expression in the myometrium. In contrast, progesterone was a more potent stimulator of endometrial PGHS-2 abundance than estradiol. Estradiol and progesterone did not regulate PGHS-1 expression in either endometrium or myometrium. The distribution and differential regulation of PGHS-1 and -2 in myometrium and endometrium are consistent with the differential functions of both enzymes.

[High performance liquid chromatographic method for the determination of ipriflavone in serum and its pharmacokinetic study in healthy volunteers]

A sensitive and rapid high performance liquid chromatographic method has been developed for the determination of ipriflavone in human serum. The average recovery of ipriflavone was 85% with relative standard deviation of 3.8%-5.4%. The calibration curve was linear in the range from 8 ng.ml-1 to 400 ng.ml-1 with gamma = 0.9981. The detection limit of the method was 3 ng.ml-1 (S/N > or = 3). The serum drug concentration-time curve exhibited a 2-compartment model and the mean T1/2 beta was 12.00 +/- 1.89 h (for ipriflavone made in Japan) and 9.05 +/- 0.80 h (for ipriflavone made in China). The AUC0-->infinity of the two kinds of ipriflavone were 804.99 ng.h.ml-1 and 807.40 ng.h.ml-1, respectively. The relative bioavailability of ipriflavone made in China vs that made in Japan was 1.003.

Effects of ADP, DTT, and Mg2+ on the ion-conductive property of chloroplast H+-ATPase(CF0-CF1) reconstituted into bilayer membrane

The purified CF0-CF1 complex of spinach was incorporated into planar lipid bilayer membranes (LBMs) formed with soybean phospholipid, and the transmembrane ion-transmission properties were studied under voltage-clamp mode. The results showed that the presence of both ADP and Pi decreased the membrane current while Dithiothreitol could evoke a stronger conductive change of CF0-CF1 containing LBMs when Ca2+ or Mg2+ exists. Mg2+ can dramatically increase the CF0-CF1 conductance in various conditions. These results indicated that the H(+)-transitive function of CF0-CF1 reconstituted in bilayer is sensitive to those factors which can affect its ATP synthase activity in vivo.

Regulation of the estrogen receptor and its messenger ribonucleic acid in the ovariectomized sheep myometrium and endometrium: the role of estradiol and progesterone

Estrogen receptor (ER) mRNA is dramatically increased in sheep myometrium and endometrium during glucocorticoid-induced premature labor and term spontaneous labor. However, the underlying mechanism for the up-regulation of uterine ER in labor is still unknown. We used ovariectomized (OVX) non-pregnant sheep to analyze the role of estradiol and progesterone in the regulation of myometrial and endometrial ER protein and ER mRNA in vivo. Twenty-one OVX ewes were treated with saline (n = 6), or with estradiol infused i.v. for 2 days (50 micrograms/day, n = 5), or with an intravaginal progesterone sponge for 10 days (containing 0.3 g progesterone, n = 5), or with an intravaginal progesterone sponge for 10 days with estradiol (50 micrograms/day) administered on Days 9 and 10 with the progesterone sponge still in place (n = 5). The ER protein concentration in both cytosolic and nuclear compartments, analyzed by Western blot, increased significantly (P < 0.05) in the myometrium after estradiol treatment, while progesterone alone had no detectable effect on ER level. Elevated ER protein was observed only in the nuclear fraction of endometrium. However, when estradiol was given together with progesterone treatment, progesterone antagonized the up-regulatory effect of estradiol on the ER level both at the endometrium and myometrium. The changes in cellular ER mRNA followed the pattern observed at the ER protein level. Estrogen receptor mRNA was elevated significantly (p < 0.01) only in estradiol-treated ewes. Expression of the ER gene in ewes receiving progesterone alone or progesterone combined with estradiol was similar to that of the control group. From these observations we conclude that ER gene expression and active ER synthesis in nonpregnant sheep myometrium and endometrium are estradiol-dependent. Progesterone antagonizes this estrogen action. Progesterone down-regulated the elevated ER mRNA when used together with estradiol. In situ hybridization showed that ER mRNA was evenly distributed in the smooth muscle cells and blood vessels of the myometrium and the epithelial cells of the glands in endometrium. In conclusion, we have observed estradiol-dependent activation of ER gene expression as well as active ER synthesis in the nonpregnant sheep myometrium and endometrium. Progesterone acted as an antagonist of estradiol on ER gene expression.

A collagen coated fabric vascular prosthesis as a punctureable A-V shunt

A fabric vascular prosthesis sealed with succinylated collagen (SC) was developed as an arteriovenous (A-V) shunt graft for hemodialysis. The SC graft was soft, pliable, flexible, and puncturable, with quick hemostasis. A needle puncture made a smaller hole in the SC graft wall than in a control expanded-polytetrafluoroethylene (e-PTFE) graft such as is usually used for an A-V shunt. The SC graft was extremely hydrous, because it is sealed with water, which is absorbed into the intermolecular spaces of negatively charged collagen. The SC suspension was injected with pressure into a knitted fabric vascular prosthesis wall (water permeability, 1,200 ml) so as to become entangled in the Dacron network. The graft then was lyophilized and thermally cross-linked. Water leakage from six holes created by an 18 G needle puncture in vitro under water pressure of 120 mmHg was 34.5 +/- 29.9 ml/min in the SC graft and 169.9 +/- 38.5 ml/min in the control e-PTFE graft. Hemostatic time at six 18G needle puncture sites on grafts implanted in the abdomen of 12 dogs was 4.5 +/- 2.5 mins in the SC graft and 34.2 +/- 11.5 mins in the control graft. After implantation, the luminal surface of the SC grafts had a thinner thrombus layer than did the control grafts. After 1 week, a thin thrombus layer covered the luminal surface of the SC grafts, and puncture sites were recognized as small dots under it, but in the control grafts, the thrombus layer was thick and the puncture sites could not be seen. These results suggest that the SC graft is less thrombogenic and has less blood leakage from the puncture sites than does the control graft.

Thermal cross-linking for biologically degradable materials. Preliminary report

To diminish undesirable side effects of chemical cross-linking of biodegradable materials, the authors developed a thermal cross-linking method that involved esterification by dehydration under dry conditions. The optimal condition for cross-linking was heating at 130-140 degrees C for 40 hr. Efficacy of the cross-linking was evaluated using enzymatic digestion of 0.01% protease in phosphate buffer at pH 7.4. Collagenous materials without cross-linking were digested completely within 30 min. However, with thermal cross-linking, it required 7 days for digestion. The capacity for holding onto water also was tested. Water content decreased when the cross-link density was increased. As an in vivo experiment, six succinylated collagen sealed vascular grafts treated with thermal cross-linking were implanted in the abdominal aortae of dogs and removed 21 days later. These grafts showed no foreign body reaction, and the collagen layer was almost completely absorbed. A collagen sealed graft cross-linked with formaldehyde used as a control showed a strong foreign body reaction. These results suggest that the physical cross-linking method was suitable for biodegradable biologicals, such as collagenous materials, without the undesirable side effects of chemical cross-linking regents.

[Effect of nanhumycin on neuromuscular transmission and its mechanism]

Nanhumycin (NHM) is a new polyether antibiotic, which suppresses the growth Bacillus subtilis and shows an anticoccidial effect. By means of intracellular recording technique, the effects of NHM on mouse phrenic nerve-diaphragm preparations were observed. The main results are as follows: (1)20 micrograms/ml NHM irreversibly blocked neuromuscular transmission in 1.5-2.0 h. (2) 2-20 micrograms/ml NHM evoked a drastic and spasmodic increase of the frequency of miniature endplate potentials (MEPPs) and a simultaneous increase of the mean quantal content of endplate potentials for 40-60 min, which was followed by complete blockage of EPPs. (3) NHM decreased the resting potential (RP) of muscle cells progressively and irreversibly. (4) NHM's effects on RP or MEPP disappeared in Na(+)-free physiological solution but persisted in the presence of tetrodotoxin (TTX). All these results support the notion that NHM is a cation ionophore, Na+ carrier.

Report of a case of sympathetic ophthalmia with special regard to ultrastructural examination

A case of sympathetic ophthalmia (SO) is reported. A long lasting stable result was obtained for this patient treated basically with traditional Chinese medicine. His exciting eye was investigated under light and transmission electron microscopes. Prominent granulomatous lesions in the choroid, Dalen-Fuchs nodules (DFNs) and disruption of outer and inner basement membrane of Bruch's membrane under DFNs are found, plasma cells are not few and melanocytes and retinal pigment epithelial cells are possibly the target cells. In various cells, nuclear bodies (NBs) are ubiquitous and sometimes multiple in an individual cell nucleus. Microtubule-like structures are present inside and outside the NBs and parallel lines composed of relatively uniform high electron dense granules as lattice-like structures can be seen. It was surmised that a virus induced autoimmune process might be involved in the pathogenesis of SO.

The role of beta 1 integrin in spreading and myofibrillogenesis in neonatal rat cardiomyocytes in vitro

The influence of the extracellular matrix (ECM) on cell behavior, myofibrillogenesis and cytoarchitecture was investigated in neonatal rat cardiac myocytes in vitro. Cell behavior was examined by analyzing cell spreading on different ECM components under a variety of experimental conditions. Area measurements were made on digitized images of cells grown for various time intervals on fibronectin (FN), laminin (LN), collagens I and III (C I+III), plastic, and bovine serum albumin (BSA). The amount of spreading was varied on the different matrices and was maximal on FN greater than LN greater than C I+III greater than plastic greater than BSA. Addition of anti-beta 1 integrin antibodies to myocytes cultured on FN, LN and C I+III blocked spreading outward on the substrates and altered normal myofibrillogenesis, especially on LN. Concomitantly, the integrin antibodies induced the formation of giant pseudopodial processes which protruded upward from the substrates. These pseudopods contained actin polygonal networks which exhibited a regular geometrical configuration. Effects of the ECM on cytoarchitecture was examined by analyzing the temporal and spatial patterns of fluorescence and immunogold labeling of cytoskeletal and integrin proteins as myocytes spread in culture. The first indication of sarcomeric patterns was the appearance at 4 hours of striations formed by lateral alignment of alpha-actinin aggregates into Z bands. At later times, vinculin at 8 hours and beta 1 integrin at 22 hours became co-localized with alpha-actinin at the Z bands and focal adhesions. These data indicate that ECM components influence myocyte spreading and that myofibril assembly and/or stability is associated with ECM-integrin-cytoskeleton associations.