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PubMed2001

Complete inhibition of vascular endothelial growth factor (VEGF) activities with a bifunctional diabody directed against both VEGF kinase receptors, fms-like tyrosine kinase receptor and kinase insert domain-containing receptor.

Vascular endothelial growth factor (VEGF) binds to and mediates its activity mainly through two tyrosine kinase receptors, VEGF receptor 1 [or fms-like tyrosine kinase receptor (Flt-1)] and VEGF receptor 2 [or kinase insert domain-containing receptor (KDR)]. Numerous studies have shown that overexpression of VEGF and its receptor plays an important role in tumor-associated angiogenesis and hence in both tumor growth and metastasis. We demonstrated previously that antagonistic antibodies to KDR specifically inhibited VEGF-stimulated receptor activation, cell migration, and endothelial cell mitogenesis. Here we constructed a recombinant bifunctional diabody that is capable of blocking both Flt-1 and KDR from binding to their ligands, including VEGF and placenta growth factor (PlGF). The diabody was expressed in Escherichia coli and purified by single-step affinity chromatography. The diabody retained the capacity to bind both KDR and Flt-1 and effectively blocked interaction between KDR and VEGF, Flt-1 and VEGF, and Flt-1 and PlGF. Furthermore, the diabody is a stronger inhibitor than its parent antibodies to VEGF-stimulated mitogenesis of human endothelial cells, as well as both VEGF- and PlGF-induced migration of human leukemia cells. Taken together, our results suggest that dual receptor blockade with the bifunctional diabody may prove to be a more efficient approach in inhibiting VEGF-stimulated angiogenesis.

3T3 Cells↗
PubMed1981

Fetal lung development in surgically induced prolonged gestation.

In our previous study we prolonged gestation in rats with daily subcutaneous injections of progesterone starting on gestation day 20 (P20). To determine whether exogenous progesterone affects the growth of post-term fetal lungs, we utilized surgical techniques to prolong gestation by retaining 4 living fetuses 1, 2, or 3 days beyond the date of spontaneous delivery of the rest of the litter. The retained fetuses were harvested by caesarean section on gestation days 21 through 25. In spite of an improved general appearance in the retained fetuses, there were many similarities between the retained and the post-term P20 fetuses such as: increase in fetal body, kidney and spleen weights; reduction in lung and liver weights; progressive lung atelectasis; loss of lung and liver glycogen; hypoglycemia; and reduction in placenta DNA content. The significant differences between the two were in the amount of lung disaturated phosphatidyl choline (DSPC) and lung DNA (cell number), expressed per lung or per body weight. In contrast to the P20 post-term fetuses, which exhibited a biphasic phenomenon in DSPC and DNA contents, the retained fetuses showed no change in lung DSPC and DNA contents after term. The P20 fetuses had larger adrenals, which increased with prolongation of gestation. The results suggest that exogenous progesterone does not affect the fetal lung growth post-term. It is speculated that the cellularity and the DSPC content of the post-term fetal lung is adversely affected by the degree of fetal distress.

Animals↗
PubMed1997

Isolation of villous microvessels from the human placenta.

A method for isolating the microvessels of the human placental villi has been developed in order to culture perivascular cells. It consists of an initial selection of the villi by serial sieving. The villi retained by the 75 microns sieve were digested by collagenase-dispase. A Percoll gradient permitted the isolation of microvessels still surrounded by stromal fibres and cells. Another digestion by collagenase-dispase eliminated the contaminant elements and allowed, after a new Percoll gradient, microvessels with endothelium, basement membrane and a few perivascular cells to be obtained. Each step of the isolation of microvessels was monitored by light or electron microscopy. Our study confirms the isolation of microvessels embedded in their basement membrane and the preservation of endothelial and perivascular cells after digestion. This method, which has permitted the culture of placental endothelial cells and pericytes, appears of interest for studying microvascular angiogenesis and permeability.

Blood Vessels↗
PubMed2001

Fetal death associated with asymptomatic intrauterine Candida albicans infection and a retained intrauterine contraceptive device.

We present a case of intrauterine fetal death at 18 weeks of gestation associated with a retained intrauterine contraceptive device and asymptomatic intraamniotic and fetal infection by Candida albicans. The infection was verified by histopathologic examination of the placenta and umbilical cord, growth of C. albicans in samples of amniotic fluid and the presence of high levels of IL-6 in the amniotic fluid.

Adult↗
PubMed1998

Anonymous unlinked testing as a sentinel approach: experience in Germany.

STUDY OBJECTIVE: To establish a laboratory sentinel as a supplementary instrument for monitoring the seroprevalence of HIV among childbearing women as a proxy to the heterosexually active population. DESIGN/SETTING: Anonymous unlinked testing of neonatal dried blood spots has been performed in central laboratories of three federal states since 1993. The survey uses residual dried blood spots collected on Guthrie cards for screening of infants for metabolic disorders. These are eluted and tested for HIV antibodies. Data retained with the specimen are only district of residence along with year and month of birth. PARTICIPANTS: Because maternal IgG crosses the placenta before birth, the presence of antibodies in newborns reflects the infection status of the mother. Childbearing women are fairly representative for the heterosexually active general population. MAIN RESULTS: The observed HIV prevalence in childbearing women of less than 1 per thousand confirms the assumption of a low rate of HIV infection in the general population. Significant time trends could not be detected, but HIV prevalence was higher in metropolitan compared with rural areas. CONCLUSIONS: Laboratory sentinels in general and the anonymous unlinked testing of neonatal dried blood spots in particular can supply additional information on HIV seroprevalence. This surveillance system could be expanded to utilise residual samples of other sources as well as to monitor the immunity against specific vaccine preventable diseases and other infectious diseases of public health relevance.

Adolescent↗
PubMed1986

An atypical insulin receptor with high affinity for insulin-like growth factors copurified with placental insulin receptors.

Insulin receptors purified from human placenta by sequential affinity chromatography on wheat germ lectin-agarose and insulin coupled to 1,1'-carbonyldiimidazole-activated agarose (CDI-agarose) retained full binding activity but bound a greater than predicted amount of 125I-labeled insulin-like growth factor I (IGF-I). IGF-I and multiplication-stimulating activity (MSA; the rat homologue of IGF-II) were equipotent in displacing either 125I-labeled IGF-I or 125I-labeled MSA from the purified receptors; insulin was 5-15 times more potent. Competitive binding studies indicated that this IGF binding activity could not be explained by cross-reaction with classical insulin receptors or by coelution of IGF-I or IGF-II receptors. Instead, it was due to a minor population of discrete atypical insulin receptors (6-18% total insulin receptors) with moderately high affinity (Kd = 2-4 X 10(-9) M) for IGF-I and MSA. These receptors were not an artifact of insulin-CDI-agarose chromatography, since they were present in wheat germ lectin-agarose-purified preparations and could also be purified from insulin-succinyldiaminodipropylamino-agarose. Affinity labeling with 125I-labeled MSA revealed that these atypical receptors had the same binding subunit (Mr 140,000) as classical insulin and IGF-I receptors. They displayed intermediate reactivity with polyclonal and monoclonal antibodies to the insulin and IGF-I receptors. It is therefore likely that insulin receptors purified by immunoadsorption would also contain atypical insulin receptors. The finding of more than one type of insulin receptor might relate to the slight variations in the cDNA nucleotide sequences and the multiple mRNA species reported for the insulin receptor [Ebina, Y., Ellis, L., Jarnagin, K., Edery, M., Graf, L., Clauser, E., Ou, J.-H., Masiarz, F., Kan, Y. W., Goldfine, I. D., Roth, R. A. & Rutter, W. J. (1985) Cell 40, 747-758].

Affinity Labels↗
PubMed1983

Characterization of solubilized opiate receptors from human placenta.

A solubilized opiate receptor from human placental membranes binds [3H]etorphine saturably, reversibly, and stereospecifically. The binding activity is shown to be truly soluble because it migrates between two soluble proteins on Sepharose CL-6B. The solubilized macromolecular complex behaves as a molecule with an apparent Stokes radius of 70 A and contains a protein as an essential constituent. The solubilized receptors bind [3H]ethylketocyclazocine with high affinity in a saturable and stereospecific manner. Naloxone inhibits [3H]etorphine and [3H]ethylketocyclazocine binding to the solubilized receptor. Sodium inhibits [3H]etorphine but not [3H]naloxone binding. These observations indicate that the solubilized receptor from human placental membranes is active and retains properties of membrane-bound receptors.

Binding, Competitive↗
PubMed2004

Non-helical type IV collagen polypeptides in human placenta.

Our previous reports showed that cultured human cells secrete non-disulfide-bonded non-helical alpha1(IV) and alpha2(IV) chains under physiological conditions. In the present report we show that the alpha(IV) chains in non-helical form were reactive to lectin ABA (Agaricus bisporus agglutinin), whereas the alpha(IV) chains secreted in triple-helical form were not. These results indicate that ABA could be used to distinguish the two conformational isomers of type IV collagen polypeptides. An alpha1(IV) chain isolated from human placenta with an antibody-coupled column showed a positive reaction to ABA, indicating that gelatin form of the type IV collagen alpha1(IV) chain is produced and retained in the tissue in vivo. A possible significance of the gelatin form is discussed from the finding that the non-helical alpha1(IV) chain purified with EDTA-free buffer contained degraded polypeptides including NC1-size domain and showed an apparent inhibition against activated pro-MMP-9. This is the first report to show that a gelatin form of protein exists in vivo.

Cells, Cultured↗
PubMed1978

Pregnant mare's serum gonadotropin: V. Indomethacin or cortisone and the reversal of antifertility efficacy of pregnant mare's serum gonadotropin.

Pregnant mare's serum gonadotropin (PMSG) of 10 IU on day 5 of pregnancy induced luteal demise and consequently an absolute resorption of fetuses and placentae resulted on day 16 of pregnancy. Simultaneous regimen of PMSG and indomethacin or cortisone was found to be consistently effective in preventing the luteolytic effect of PMSG. The growth of the fetuses, placentae as well as corpora lutea was found to be parallel to controls. Similarly, shortening of the duration of pseudopregnancy to 10--12 days in the bilaterally hysterectomized rat by PMSG and its retaining the normal duration of 18--20 days in the presence of indomethacin tempt us to propose that the PMSG-induced luteolysis is possibly reflected through the release of prostaglandin at the ovarian level.

Animals↗
PubMedDate not supplied

Strontium retention in mouse foetuses at different intervals after contamination of the dam.

Pregnant CBA mice were intravenously contaminated with radiostrontium (85Sr) on either the 14th, 16th or 18th day post coitum. The radiostrontium content in the foetuses and corresponding placentas as well as that in the femurs of the mothers was measured separately and individually on the 19th day post coitum, i.e. after intervals of 5, 3 and 1 day, respectively. The retained amount of strontium in the foetuses successively increased by the time of contamination, i.e. the later during pregnancy the contamination occurred. Expressed as per cent of the injected amount of 85Sr, the figures ranged from 4.6 per cent in foetuses contaminated on the 18th day to 0.7 per cent for those contaminated already on the 14th day after coitus, with a significantly negative correlation between time and retained amount of radiostrontium. The amount of strontium in the femurs of the mothers was reduced within the same intervals, due partly to decalcification of the skeleton of the mother during the latest part of the pregnancy.

Animals↗
PubMedDate not supplied

[Pregnant rats consuming diets with uncooked and fried olive oil, mineral levels in their offspring and changes in their body storage levels].

Some parameters relating nutritional utilization of Ca, Mg, Fe and Zn were studied in rats fed with diets including raw and fried fats in order to study more in depth the diet fat/mineral utilization interaction. Wistar rats having initial weights of 176 g were divided into two groups and fed isocaloric diets having 15% fat content as raw olive oil and fried olive oil (from 15 potato fryings), during pregnancy. Weight and dietary intake were controlled and mineral content changes in plasma, liver, spleen and carcass were assessed, as well as litter mineral uptake. Throughout the study, dietary intake of pregnant rats fed raw (R) and fried oil (F), body weight gain and final weight gain were similar. Serum Fe, Zn and Ca levels decreased at a similar rate in both groups. Liver Fe levels decreased more in the F group while spleen Fe decreased more in the R group, these changes started on day 18. Liver Zn levels did not show clear changes but spleen Zn decreased during the last three days of pregnancy. Carcass Ca levels of pregnant rats from the R and F groups did not show any differences at the end of pregnancy. Body weight gain, Ca, Mg, Fe and Zn uptake of the litter were similar in both groups throughout the study. The placentas and the offspring of treated rats showed similar absolute and relative mineralization values. These findings lead us to conclude that fried olive oil retained the same characteristics as raw olive oil regarding mineral utilization.

Animals↗
PubMed1984

Metabolism of prostaglandin F2 alpha in the fetal circulation of the human term placenta in vitro.

The metabolism of prostaglandin F2 alpha (PGF2 alpha) was investigated in the fetal cotyledons of human term placentas by an in vitro perfusion technique. When 80 nmol of 14C-PGF2 alpha was infused in 2 min into the chorionic artery, 56 +/- 7% (mean +/- SEM, n = 7) of the infused radioactivity appeared in the nonrecirculating venous effluent in 6 min. Most of this radioactivity was as unmetabolized PGF2 alpha. Only 12 +/- 2% of the radioactivity in this venous effluent was as metabolites, the major metabolite being 13,14-dihydro-15-keto-PGF2 alpha. During the following 2 min, 2 +/- 1% of the infused radioactivity appeared in the venous effluent. The fluid trickling through the decidual plate contained 5 +/- 1% of the infused radioactivity. After the perfusion 10-15% of the infused radioactivity was retained in the tissue, being mainly as 13,14-dihydro-15-keto-PGF2 alpha. The oxygen consumption of the tissue was 0.4 +/- 0.1 ml/100 g/min, which is adequate for vital placenta tissue. The study suggests that the metabolism of PGF2 alpha is negligible in the fetal circulation of the human term placenta.

Dinoprost↗
PubMed1985

Estrogen sulfotransferase in human placenta.

Human placental estrogen sulfotransferase (ESFT) was partially purified from the term placental cytosol by (NH4)2SO4 precipitation and agarose gel chromatography. Additional purifications caused a rapid loss of the enzyme activity. The activity was abolished by isoelectrofocusing but partially retained by chromatofocusing. The value of pI of human placental ESFT is 5.8 and the same value was obtained for bovine adrenal ESFT. The enzyme protein was able to bind to the affinity resin, estradiol-17-hemisuccinyl-1,2-diaminododecane sepharose 4B, but difficult to be extracted by estradiol (E2). The extract of the affinity resin showed one major protein band at 68,000 dalton on SDS-polyacrylamide gel electrophoresis. Kinetic studies using partially purified ESFT revealed that E2 is the best substrate for this enzyme. The relative rate of sulfurylation of E2, estrone, estriol and dehydroepiandrosterone at 4 microM (Km for E2) is 1, 0.3, 0.08 and 0.08, respectively.

Chromatography, Affinity↗
PubMed1985

Laboratory and human studies on polychlorinated biphenyls (PCBs) and related compounds.

Similar qualitative toxic effects have been observed in animals for a class of halogenated aromatic compounds, which include the halogenated biphenyls, naphthalenes, dibenzodioxins, and dibenzofurans. All of these compounds are lipid soluble and persist in the environment and in mammals. The polybrominated biphenyls (PBBs) are the most persistent. They are predominantly stored in fatty tissue; they pass the placenta and are excreted in milk. Some isomers of the halogenated biphenyls are more toxic than others. With some exceptions, the more toxic isomers are retained longer in tissues and are also the carcinogenic components of the mixture. Most of these chemicals seem to be promoters of carcinogenesis in animals rather than initiators. An array of toxic effects in laboratory animals has been ascribed to these compounds and numerous reviews summarizing this information are available. Less information is available on the human health effects of environmental and occupational exposure. Results of recent studies in animals to further elucidate the effects of these chemicals are presented, and results from some human studies conducted in the United States are reviewed.

Accidents↗
PubMed1976

Identification of a butanol-extractable human placenta-specific antigen with alkaline phosphatase activity.

N-Butanol extracts of whole-term placenta from different individuals were prepared, and used as immunogens to raise heterologous hyperimmune sera in rabbits. Upon immunoelectrophoresis the anti-placenta antisera could recognize at least six antigenic components in the placental extract even after they had been completely absorbed with pooled male serum proteins. However, the antisera so absorbed, designated (-PMS) antisera, could still react strongly with several normal adult tissue extracts including kidney. Systematic and quantitative absorptions of the (-PMS) antisera were thus further carried out with individual butanol extracts of normal adult liver, lung, intestine, stomach, kidney, bone, pancreas, spleen, heart, cerebrum, cerebellum, breast, and packed red cells, as well as a composite extract containing equal amounts of each of the 13 adult tissue extracts. Of the six antigenic components in the placental extracts reacting with the (-PMS) antisera the only one which retained its reactivity with the antisera throughout exhaustive absorptions was associated with alkaline phosphatase activity. This immunologic and enzymologic identity was confirmed with homogeneous placental alkaline phosphatase. Extracts from each of three placentae injected into three pairs of rabbits all produced an identical antibody reaction with the unique determinant(s) of placental alkaline phosphatase. The same identity of precipitin reaction was also found with extracts of 14 other placentae against each of these antisera. It thus firmly establishes that placental alkaline phosphatase is a characteristic placenta-specific fetal protein.

Absorption↗