[Histochemical studies on the glycoconjugates of experimental alkali burned cornea in rabbit]

The model of experimental alkali burn of cornea in rabbit was obtained using 1 mol/L NaOH solution. After being burned for 1, 3, 7 and 14 days, the histochemical changes of these models were studied by using labelled concanavalin A (ConA-FITC) and wheat germ agglutinin (WGA-FITC). The results showed that after being burned, the amount of glycoconjugates interacted with these lectins decreased, and increased gradually after 7 days, then reached the level higher than that in the normal cornea. These changes were related to the recovery of alkali burned cornea.

Increased number of GABAB receptors in the lethargic (lh/lh) mouse model of absence epilepsy

This study begins to explore possible mechanisms underlying the role of GABAB receptors in absence seizures in lethargic (lh/lh) mice. To test the hypothesis that alterations intrinsic to the GABAB receptor underlie enhanced synaptic activation of these receptors in absence seizures, we measured GABA-displaceable [3H]baclofen binding to neocortical plasma membranes prepared from lh/lh and wild (+/+) age-matched congenic mice. The number (Bmax) of binding sites was significantly greater (20%) in lh/lh (4.2 pmol/mg protein, n = 43 pairs, P < 0.02) than in +/+ mice (3.3 pmol/mg protein) in an age-independent manner. Interestingly, the subset of lh/lh mice with greater seizure frequency (40-70 seizures/15 min, measured by bipolar electrodes implanted into neocortex; n = 11) had a significantly greater Bmax (P < 0.003) than the subset with lower seizure frequency (1-10 seizures/15 min; n = 11). The equilibrium dissociation constant (Kd) was unchanged (60 nM in both). The Kd of both strains was inhibited to an equal degree by the nonhydrolysable GTP analogue 5'-guanylimido-diphosphate [Gpp(NH)p]. The increased number of GABAB binding sites was selective, because binding to NMDA sites ([3H]glutamate binding) and to GABAA sites ([3H]muscimol binding) was not significantly different in the two strains. These data suggest that the increased number of GABAB receptors in lh/lh mice underlies enhanced synaptic activation of these receptors. Together with evidence that GABAB receptor activation can produce disinhibition, our data support a role for GABAB receptors in the expression of absence seizures in lh/lh mice.

Induction of c-fos mRNA by kindled seizures: complex relationship with neuronal burst firing

Expression of the immediate-early gene c-fos has been advanced as a marker of neuronal activity in the adult nervous system. We sought to test the validity of c-fos mRNA expression as a marker of neuronal activity during seizures and to elucidate specific neurotransmitter receptors whose activation was necessary for seizure-evoked c-fos mRNA expression. We correlated c-fos mRNA expression, measured with in situ hybridization, with kindled seizure-induced firing of hippocampal dentate granule cells or substantia nigra pars compacta and pars reticulata neurons. We found that the occurrence of seizure-evoked synchronous action potentials during the seizure exhibited a perfect qualitative correlation with the presence of c-fos mRNA expression in the granule cells 30 min following the seizure (Fisher's exact test, p = 0.002). However, there was no quantitative correlation between the number of seizure-induced population action potentials and the magnitude of c-fos mRNA expression in the granule cells. In the substantia nigra, where neuronal populations have previously been demonstrated to exhibit synchronous firing during kindled seizures, no induction of c-fos mRNA was detected in either pars compacta or pars reticulata. Pretreatment with antagonists of the NMDA subtype of glutamate receptor selectively and markedly decreased seizure-induced c-fos mRNA expression in the dentate granule cells, despite increasing the number of granule cell population action potentials. These findings illustrate the complexity of the relationship between c-fos induction and neuronal burst firing during kindled seizures.(ABSTRACT TRUNCATED AT 250 WORDS)

The role of amino-terminal disulfide bonds in the structure and assembly of human fibrinogen

Human fibrinogen contains two half-molecules, each composed of an alpha, beta, and gamma chain linked by disulfide bonds. The two half-molecules (alpha beta gamma) are held together in the native protein by additional disulfide bonds located in the amino terminus of each chain. Site-directed mutagenesis, in which the amino-terminal Cys residues (alpha-Cys28 and 36, beta-Cys65, and gamma-Cys8 and 9) were converted to Ser, was carried out in order to study the role of the amino-terminal disulfide bonds in the structure and assembly of fibrinogen. An analysis of the fibrinogen synthesized in transfected baby hamster kidney (BHK) cells employing various combinations of these mutations revealed that alpha-Cys36 and beta-Cys65 form disulfide bonds between two alpha beta gamma half-molecules, rather than within the same half-molecule; furthermore, these two disulfide bonds are sufficient to hold the two alpha beta gamma half-molecules together as intact fibrinogen. Disulfide bonds formed by gamma-Cys8 and 9 were also sufficient to hold the two fibrinogen alpha beta gamma half-molecules together, while the disulfide bond between the two alpha-Cys28 residues failed to form in the absence of the disulfide bonds linking the alpha and beta chains and the two gamma chains.

Relative roles of CCAAT/enhancer-binding protein beta and cAMP regulatory element-binding protein in controlling transcription of the gene for phosphoenolpyruvate carboxykinase (GTP)

The gene for phosphoenolpyruvate carboxykinase (GTP) (EC 4.1.1.32) (PEPCK) is expressed in a tissue-specific manner in the liver, kidney, and adipose tissue and is regulated by hormones including cAMP and insulin. Previous studies have shown that the CCAAT/enhancer-binding protein alpha (C/EBP alpha) binds to several sites on the PEPCK promoter and activates transcription from the promoter in hepatoma cells. Here, we report that a second member of the C/EBP family, C/EBP beta, bound to the same sites on the PEPCK promoter. However, C/EBP beta stimulated transcription primarily through the cAMP-responsive element (CRE), which maps between positions -77 to -94, but not at the more 5'-binding sites. In addition, the nuclear factor-1 site, which is immediately adjacent to the CRE in the PEPCK promoter, was also required for the full response of the promoter to cotransfected C/EBP beta. In gel mobility assays, antibodies to both C/EBP beta and the cAMP regulatory element-binding protein (CREB), but not to C/EBP alpha, "supershifted" DNA-protein complexes formed between a synthetic CRE oligomer and proteins prepared from rat liver nuclei. C/EBP beta mRNA was expressed at low levels in both the periportal and pericentral regions of the liver lobule, whereas expression of the gene for C/EBP alpha was confined to the pericentral region of the liver lobule. PEPCK gene transcription is greatest in the periportal region of the liver. CREB also bound to the CRE and stimulated transcription of a PEPCK-CAT vector in the presence of an expression vector for the catalytic subunit of protein kinase A. C/EBP beta and CREB bound to the CRE with similar affinities, both of which were greater than the affinity of C/EBP alpha. Within 90 min after the administration of dibutyryl cAMP to rats, there was a marked increase in the hepatic concentration of C/EBP beta mRNA and a decrease in the level of mRNA for C/EBP alpha. These studies indicate that C/EBP beta can regulate PEPCK gene transcription by acting through the CRE and that C/EBP beta, together with CREB, may contribute to the cAMP responsiveness of the PEPCK promoter.

Role of CAAT-enhancer binding protein isoforms in the cytokine regulation of acute-phase plasma protein genes

Rat hepatic cells respond to interleukin (IL) -1, IL-6, and dexamethasone treatment by increasing the transcription rate of acute-phase plasma protein genes. The same conditions lead to changes in the expression of CAAT-enhancer binding protein (C/EBP) isoforms which are specific to the hepatic cell line. To identify the relationship between C/EBP isoforms and acute-phase protein gene activation, the hormone-specific expression of C/EBP alpha, beta, and delta was determined in H-35 and HTC cells and was compared to acute-phase liver. C/EBP beta was found to be the principal isoform in hepatoma cells and to be strongly stimulated by cytokines and dexamethasone in H-35 cells. Transactivating functions were observed for all three C/EBP isoforms by cotransfection of CAT gene reporter constructs containing cytokine and glucocorticoid response elements of acute-phase protein genes and expression plasmids for mouse C/EBP alpha, beta, and delta into rat and human hepatoma cells. The degree of C/EBP-mediated transactivation was, however, extremely variable among the different regulatory elements. Transcription run-on reactions with nuclei from transiently transfected H-35 cells indicated that cotransfected C/EBP beta increases basal expression of reporter gene constructs as well as the dexamethasone-mediated stimulation of constructs containing the glucocorticoid response elements of the rat alpha 1-acid glycoprotein gene, but did not accelerate or enhance hormone-dependent transcription activation of reporter gene plasmids containing the IL-6 regulatory element of the beta-fibrinogen gene. Activation of the reporter gene constructs appeared to be temporally and quantitatively correlated with the amount of nuclear C/EBP as determined by two-dimensional Western and Southwestern blot analyses.

Performance characteristics of transmission imaging using a uniform sheet source with parallel-hole collimation

Transmission imaging is receiving increasing attention in SPECT due to the need to compensate for nonuniform attenuation in cardiac-chest SPECT. The quality of a transmission image has an important effect on the measured attenuation distribution. To improve image quality, knowledge of the performance characteristics of a transmission imaging system is essential. The characteristics, spatial resolution, detection efficiency, photon flux, and exposure to the object, of a transmission imaging system consisting of a gamma camera and a uniform sheet source have been studied. The results demonstrate that spatial resolution of a transmission imaging system can be improved by use of a high-resolution source collimator at the price of a moderate decrease in detection efficiency, in comparison to the uncollimated case. Also, the source collimator significantly reduces the photon flux and exposure to the object. This investigation suggests that a high-resolution collimator be used with an intense sheet source to improve spatial resolution and reduce statistical noise with low exposure to the patient. This research further suggests that the amount of source activity is determined by the requirement of image quality, detection geometry, and allowed absorbed dose to the patient.

The role of GABAB receptor activation in absence seizures of lethargic (lh/lh) mice

Lethargic (lh/lh) mice, which function as an animal model of absence seizures, have spontaneous seizures that have behavioral and electrographic features and anticonvulsant sensitivity similar to those of human absence seizures. Antagonists of the gamma-aminobutyric acidB (GABAB) receptor suppressed these seizures in lethargic mice, whereas agonists of GABAB receptors exacerbated them. Furthermore, GABAB receptor binding and synaptically evoked GABAB receptor-mediated inhibition of N-methyl-D-aspartate responses were selectively increased in lh/lh mice. Therefore, enhanced GABAB receptor-mediated synaptic responses may underlie absence seizures in lh/lh mice, and GABAB receptor antagonists hold promise as anticonvulsants for absence seizures.

A scanning electron microscopic observation of inner carious dentin after cleansing and of the dentin-resin interface

Inner carious dentin after cleansing and the dentin-resin interface were observed with scanning electron microscopy. Results suggested that, similar to 10% citric acid-3% ferric chloride solution, 10% ethylenediaminetetraacetic acid may thoroughly remove the smear layer on the surface of inner carious dentin and make it possible for the dentinal bonding agent to penetrate the cleansed dentin to form an acid-proof layer and dense resin tags. These changes may improve the bond strength as well as tubule aperture seal. Ethylenediaminetetraacetic acid is not destructive to collagen, and may be of negligible toxicity to the pulp of intact dentin.

Calcium-regulated phosphorylation within the leucine zipper of C/EBP beta

Alterations in intracellular calcium levels activate several signal transduction pathways resulting in distinct patterns of gene expression. Here, a pathway for calcium-mediated signals is demonstrated that involves C/EBP beta, a member of the bZip family of transcription factors. In pituitary cells C/EBP beta was phosphorylated in response to increased intracellular calcium concentrations as a consequence of the activation of a calcium-calmodulin-dependent protein kinase. Phosphorylation of serine at position 276 within the leucine zipper of C/EBP beta appeared to confer calcium-regulated transcriptional stimulation of a promoter that contained binding sites for C/EBP beta.

[Study of the estrogen receptor and progesterone receptor in human cervical carcinoma]

Three hundred and twelve different cervical specimens have been tested for estrogen (ER) and progesterone receptor (PR) content with dextran-coated charcoal method (DCC). The results showed that the concentrations of ER and PR in normal cervical tissues were higher than those in malignant cervical tissues, and that the percentage of positive scores for ER and PR in cervical squamous epithelial tissues were higher than that in malignant cervical tissues. That the variances of ER and PR in cervical malignant tumors were not parallel suggested that the production or/and the mechanism of receptor action might be impaired. The percentage of positive scores for ER was not correlated with the clinical stages whereas that of PR was inversely proportional to clinical stages. That some patient with cervical cancer had high level of PR and had both ER and PR positive implied the possibility for endocrine therapy. The content and distribution of ER and PR in normal cervical tissues are consistent with the effects of sex hormone.

[Effect of radix Astragali and radix ginseng in enhancing the metabolism of human myocardial cells in vitro]

Our experiment indicated that in Radix Astragali and Radix Ginseng treated human myocardial cell cultures the level of LDH and SDH elevated in varying degrees and in Radix Ginseng treated cells the cAMP showed higher levels but in Radix Ginseng treated ones the same was not observed. This suggests that the metabolism of myocardial cells is enhanced by Radix Astragali or Radix Ginseng.

[Immunodiagnosis of ovarian cancer]

Ovarian tumor associated antigen was isolated from human serous cystadenocarcinomas of ovary and purified by using affinity chromatography columns coupled to anti-normal female serum and anti-normal ovarian tissue gamma globulin. Antiserum was prepared from New Zealand white rabbits. The antiserum was absorbed with normal female serum and extracts of normal ovarian tissue thoroughly. The absorbed antiserum was appraised by immunodiffusion, immunoelectrophoresis and counter-immunoelectrophoresis with intensifiers. The absorbed antiserum has a specific immune precipitin with extracts of ovarian tumor tissue. Counter-immunoelectrophoresis with intensifiers was used to detect the ovarian tumor associated antigen in the tissue and serum of various patients. Twenty-eight of 40 ovarian tumor extracts and 1 of 5 cervical carcinoma extracts showed the presence of the cancer antigen. 14/40 were positive in the sera of ovarian tumor patients and 6/10 positive in the sera of ovarian serous cystadenocarcinoma patients; 1/5 positive in the sera of cervical carcinoma patients and 2/10 positive in the sera of ovarian cysts patients. No positive result for the sera of normal females was noted. The specificity, sensitivity and accuracy of the method were 94.7%, 42.3% and 83.3%, respectively.

[Preparation of monoclonal antibodies against chorionic gonadotropin receptor and study of its characteristics]

We reported the production of monoclonal antibodies (McAbs) against chorionic gonadotropin hormone (CG) receptor by fusing spleen cells of BALB/c mice which had been immunized by purified bacteria (Pseudomonas maltophilia) CG receptor with mouse myeloma line SP2/0. Four hybridoma cell lines secreting CG receptor McAbs were obtained (ED490 DG390, AB890 and GE590). The titers of specific antibodies of both mice ascites and culture supernatant were 10(-2)-10(-6) and 1-10(-2) respectively, by solid phase ELISA. Double-Immunodiffusion test showed that the McAb GE590 was IgG1, and the McAbs ED490, DG390 and AB890 were IgG2b Immunoprecipitation indicated that 125I-HCG could bind the HCG receptor which had reacted with McAbs ED490, AB890 and DG390, suggesting that they may recognize the receptor with different antigenic determinant. Interaction of McAb GE590 with the receptor showed that the increased concentration of GE590 was in inverse proportion to the amount of 125I-HCG binding receptor, indicating that both the McAb and 125I-HCG could recognize a common site of receptor and that increased concentration of McAb GE590 may induce some change in conformation and structure of the receptor. Our study suggested that these McAbs may be used for studying structure of CG receptor.

Regulated expression of three C/EBP isoforms during adipose conversion of 3T3-L1 cells

In an effort to identify protein factors that play a regulatory role in the differentiation of adipocytes, we have isolated two genes that encode polypeptides related to CCAAT/enhancer-binding protein (C/EBP; hereafter termed C/EBP alpha). The proteins encoded by these C/EBP-related genes, termed C/EBP beta and C/EBP delta, exhibit similar DNA-binding specificities and affinities compared with C/EBP alpha. Furthermore, C/EBP beta and C/EBP delta readily form heterodimers with one another as well as with C/EBP alpha. The transcriptional activating capacity of these two newly identified C/EBP isoforms was demonstrated by transient transfection experiments in which expression vectors encoding C/EBP beta and C/EBP delta were observed to induce transcription from the promoter of the serum albumin gene in cultured hepatoma cells. The mRNAs encoding C/EBP beta and C/EBP delta were detected in a number of tissues, most of which corresponded to sites of expression of C/EBP alpha. The expression pattern of C/EBP beta and C/EBP delta during adipose conversion of 3T3-L1 cells was examined by Western and Northern blotting assays. In contrast to the expression profile of the gene encoding C/EBP alpha, whose product is not detectable until the late phase of adipocyte differentiation, the c/ebp beta and c/ebp delta genes were actively expressed very early during adipocyte differentiation. Moreover, transcription of the c/ebp beta and c/ebp delta genes was observed to be induced directly by adipogenic hormones. The accumulation of C/EBP beta and C/EBP delta reached a maximal level during the first 2 days of differentiation and declined sharply before the onset of C/EBP alpha accumulation. The temporal pattern of expression of these three C/EBP isoforms during adipocyte differentiation may reflect the underpinnings of a regulatory cascade that controls the process of terminal cell differentiation.

Increased AMPA-sensitive quisqualate receptor binding and reduced NMDA receptor binding in epileptic human hippocampus

Based on results from the kindling model of epilepsy, we hypothesized that enhanced binding of radioligands to the NMDA receptor and decreased binding to the alpha-amino-3-hydroxy-5-methyl-4- isoxazolepropionate (AMPA)-sensitive quisqualate (ASQ) receptor would be found within epileptic hippocampi of humans with complex partial epilepsy (CPE). To test these hypotheses, we used tissue that was surgically removed from patients with intractable CPE, and control tissue that was obtained at autopsy. We used autoradiographic techniques to measure ASQ receptor binding (with 3H-AMPA as the radioligand) and binding to 2 sites on the NMDA receptor/channel complex: the agonist recognition site (with 3H-glutamate) and the phencyclidine (PCP) binding site that resides within the NMDA channel [with 3H-N-(1-[thienyl]cyclohexyl) piperidine (TCP) in the presence of saturating concentrations of NMDA and glycine]. Measurements of receptor binding were corrected for pathologic alterations in neuronal density. Contrary to our expectations, ASQ receptor binding was significantly increased (100%; p less than 0.02) in the dentate gyrus stratum moleculare in patients with CPE (n = 8), and it was unchanged in other hippocampal regions. In nearby sections from the same specimens, binding was significantly decreased to the agonist recognition site of the NMDA receptor in the stratum oriens of area CA3 (46%; p less than 0.05) and was also decreased to the PCP site in the stratum radiatum and stratum oriens of CA3 (44% and 74%, respectively; p less than 0.05). The increase in ASQ receptor binding may contribute to hyperexcitability in these epileptic patients.(ABSTRACT TRUNCATED AT 250 WORDS)

[Production and characterization of anti-human hepatocellular carcinoma monoclonal antibodies]

The hepatocellular carcinoma (HCC) cell line, QGY-7703, derived from a Chinese patient, was used to immunize the BALB/c mice. Fifteen hybridomas producing McAb that reacted with QGY-7703 cells were isolated from 858 hybridomas created in three cell fusions. In further studies two McAb, namely, AQGY1 and A-QGY2, were selected which specifically stained HCC cells grown in vitro. The reactivity of these McAb was not removed by the absorption by homogenates of the normal liver, but was by homogenates of HCC cells. A-QGY1 and A-QGY2 also reacted definitely with HCC cells in liver tissues of HCC patients, but neither with other cells in the tissues nor with nontransformed liver tissues of the same patients. Furthermore these two McAb stained the adult or fetal liver tissues, nor all of the other normal or tumor tissues that had been tested. Blocking and absorbing experiments revealed that A-QGY1 and AQGY2 antigens had no immunohomogenicity with antigens such as HBsAg, HBcAg, HBeAg, AFP and CEA. The specificity of these two McAb may be used potentially for the sero diagnosis, histologic identification, radioimmunoimaging and destruction of human hepatocellular carcinoma.

[Primary serologic investigation of HBV-like virus existence in domestic animals and fowls]

Using the reagent kits for detecting human HBV, primary serologic investigation was made in 6 kinds of domestic animals and fowls (total 673) by ELISA, spot hybridization and immuno-electronmicroscopy. The results showed that some sera samples of pigs, rabbits, chicken and geese were HBsAg, HBeAg positive and positive for spot hybridization by using 3(2)P-HBV-DNA probe, which suggested that HBV-like viruses might exist in those domestic animals and fowls. HBV-like virus particles were seen in one pig serum sample which was HBsAg positive. The particles could be divided into three forms in shape, large spherical particle (40-55nm), small spherical particle (20-30nm) and short filament particle. The further studies are needed.

[3H]prostaglandin uptake in vivo by rabbit uterine tissues and blastocysts

Day-6 pregnant rabbits were anesthetized and subjected to a mid-ventral laparotomy. [3H] Prostaglandin F2alpha) (PGF2alpha) [3H]PGE2, [14C]Urea or [14C]Sucrose were instilled into the uterine lumen via the uterotubal junction. The amounts instilled/uterine horn were respectively 3.7 +/- 0.3, 3.5 +/- 0.3, 5.7 +/- 1.3 and 2.7 +/- 1.6 muCi in 20mul of buffer. Animals were killed at 1, 2, 9, 19 or 21 h after radioactive instillation, and the amounts of radioactivity in blastocysts, uterine tissue, peritoneal cavity washings and urine evaluated by liquid scintillation spectrometry. A gradient of radioactivity was observed from the uterotubal junction to the cervical end of the uterus. Large amounts of [3H]PG were found in the injected horn and associated blastocysts with a considerable crossover to the non-injected horn, but little in the associated blastocysts. Much of the blastocysts associated- [3H]PG remained unmetabolized. Large amounts of metabolized [3 H] were found in urine. [14C]Urea was taken up by uterine tissue in the injected horn, but there was little cross over to the non-injected horn. Urea was also found in urine. Much of the [14C]Sucrose remained in the injected horn, and little was recovered from the urine. It was found that at 9 h, but not at 19 h, after [3 H]PG instillation, the PG was localized at the site of the blastocysts in the injected but not in the contralateral horn. Significantly more [3H]PGF2alpha than [3H]PGE2 was localized in this situation. [14C]Urea was not localized at the site of the blastocysts in urea injected horns. (ABSTRACT TRUNCATED AT 250 WORDS)

[Electron microscopic observation of the effects of Rhodiola kirilowii (Regel.) Maxim. in preventing damage of the rat viscera by a hypoxic high altitude environment]

This paper has shown that the pathologic damages done to rat's viscera due to hypoxic environment of altitude can be reduced significantly by oral administrations of Shengmaiyin, Danshen-Chuanxiong mixture and Rhodiola kirilowii. Shengmaiyin that maintains interior substances in the plate layer bodies proves more effective than Danshen-Chuanxiong mixture, while the latter excels in preventing capillary contraction, thus improving blood circulation. Rhodiola kirilowii has the effects of both Shengmaiyin and Danshen-Chuanxiong mixtures.

Regulation of cell-type-specific transcription and differentiation of the pituitary

The transcription of rat prolactin and growth hormone genes in vitro requires a pituitary transcription factor, specific to certain cell types in the pituitary, which currently appears to be the PUF-I/Pit-1/GHF-1 protein. This factor binds to cis-regulatory elements in the 5' region of both genes and exerts a positive influence on transcription initiation presumably by interacting with general transcription factors. The PUF-I/Pit-1/GHF-1 transcriptional regulatory protein probably has an important role in not only the differentiation of the pituitary lactotroph/somatotroph cell lineage; it is also expressed in the early development of the nervous system but its function there is less well documented. It appears to be one member of a family of trans-activator proteins involved in differential gene expression in several cell types.

[Acute toxicity of flesh oil of Hippophae rhamnoides L. and its protection against experimental hepatic injury]

Protection by flesh oil of Hippophae rhamnoides against hepatotoxicity induced by CCl4 and acetaminophen (AAP) is reported in this paper. It was found that the oil markedly inhibited MDA formation of liver induced by CCl4 and AAP, decreased sGPT levels induced by CCl4 and blocked depletion of GSH damaged liver induced by AAP.LD50 greater than 45.0 g/kg.

Dual functions of a cis-acting element within the rat prolactin gene promoter

Within the promoter region of the rat prolactin gene lies a TA-rich imperfect palindrome. The possible functions of the 18-base-pair symmetrical sequence were investigated by using an in vitro transcription system. Prolactin templates with and without the palindrome were transcriptionally assayed in both pituitary and nonpituitary extracts. Our results indicated that the palindromic sequence has at least two functions in the regulation of prolactin transcription.

Long-range surface modes of metal-clad four-layer waveguides

The surface modes of metal-clad four-layer waveguides were theoretically analyzed. We showed that the long-range surface modes can be excited in such waveguides. The long-range surface modes were experimentally studied with the angle scanning attenuated-total-reflection method; the dependence of wave vector and loss of these modes on the waveguide parameters were measured. Experimental results were in good agreement with theoretical calculations.

Capillary permeability changes in the uteri of recipient rabbits after transfer of blastocysts from indomethacin-treated donors

Blastocysts recovered from control or indomethacin-treated (10 mg/kg s.c. twice daily starting on Day 4.5 of pregnancy) donor rabbits were transferred to the uteri of Day-6 or 6.5 pseudopregnant recipients. The minimal time required to cause an increase in capillary permeability in the endometrium underlying control blastocysts was approximately 9 h. Blastocysts derived from the indomethacin-treated donors were depleted of PGE and PGF (determined by RIA) and were unable to produce any increase in capillary permeability during the same time period, although after 46 h in vivo the diameters of the implantation swellings related to control or indomethacin-treated blastocysts were not different. This suggests that, in the untreated recipients, blastocysts depleted of PGs can become replenished and then release these PGs in a site-directed manner. Indomethacin thus causes a delay rather than a complete inhibition of implantation. Incubation of the indomethacin-treated blastocysts in vitro led to replenishment with PGs, but such replenished blastocysts failed to induce an increase in capillary permeability within the same time-frame as control blastocysts. Evidence is presented that indomethacin is probably not the cyclooxygenase inhibitor of choice, since it interferes with PG uptake and efflux. Such an action could explain the failure of the replenished blastocysts to induce a normal increase in capillary permeability.