A Novel ALDH1A1 Inhibitor Targets Cells with Stem Cell Characteristics in Ovarian Cancer

A small of population of slow cycling and chemo-resistant cells referred to as cancer stem cells (CSC) have been implicated in cancer recurrence. There is emerging interest in developing targeted therapeutics to eradicate CSCs. Aldehyde-dehydrogenase (ALDH) activity was shown to be a functional marker of CSCs in ovarian cancer (OC). ALDH activity is increased in cells grown as spheres versus monolayer cultures under differentiating conditions and in OC cells after treatment with platinum. Here, we describe the activity of CM37, a newly identified small molecule with inhibitory activity against ALDH1A1, in OC models enriched in CSCs. Treatment with CM37 reduced OC cells' proliferation as spheroids under low attachment growth conditions and the expression of stemness-associated markers (OCT4 and SOX2) in ALDH+ cells fluorescence-activated cell sorting (FACS)-sorted from cell lines and malignant OC ascites. Likewise, siRNA-mediated ALDH1A1 knockdown reduced OC cells' proliferation as spheres, expression of stemness markers, and delayed tumor initiation capacity in vivo. Treatment with CM37 promoted DNA damage in OC cells, as evidenced by induction of γH2AX. This corresponded to increased expression of genes involved in DNA damage response, such as NEIL3, as measured in ALDH+ cells treated with CM37 or in cells where ALDH1A1 was knocked down. By inhibiting ALDH1A1, CM37 augmented intracellular ROS accumulation, which in turn led to increased DNA damage and reduced OC cell viability. Cumulatively, our findings demonstrate that a novel ALDH1A1 small molecule inhibitor is active in OC models enriched in CSCs. Further optimization of this new class of small molecules could provide a novel strategy for targeting treatment-resistant OC.

The effect of parotid gland-sparing intensity-modulated radiotherapy on salivary composition, flow rate and xerostomia measures

OBJECTIVES

To describe parotid gland (PG) saliva organic and inorganic composition and flow rate changes, after curative intensity-modulated radiotherapy (IMRT) for head and neck cancer (HNC), and analyse the relationship between PG saliva analytes and xerostomia measures.

METHODS AND MATERIALS

Twenty-six patients recruited to five prospective phase 2 or 3 trials which assessed toxicity and efficacy of IMRT by HNC subsite, provided longitudinal PG saliva. Salivary flow rate, and subjective and objective xerostomia measures were prospectively collected and saliva tested for inorganic and organic analytes. Statistical comparisons of longitudinal analyte changes and analysis for a relationship between dichotomized xerostomia score and saliva analytes were performed.

RESULTS

One hundred and forty-two PG saliva samples from 26 patients were analysed. At 3-6 months after IMRT, stimulated and unstimulated saliva showed significantly decreased flow rate, total protein (TP) secretion rate, phosphate concentration and increased lactoferrin (LF) concentration. Stimulated saliva alone had elevated LF secretion rate and beta-2-microglobulin (B₂ M) concentration with decreased calcium (Ca²⁺ ) and magnesium (Mg²⁺ ) concentrations and Ca²⁺ secretion rate. At >12 months, under stimulated and unstimulated conditions, increased LF concentration and decreased Mg²⁺ and phosphate concentration persisted and, in stimulated saliva, there was decreased potassium (K⁺ ) and Mg²⁺ concentration. Unstimulated TP secretion rate was lower in the presence of high-grade xerostomia. Otherwise, no relationship between xerostomia grade and PG salivary flow rate, TP and Ca²⁺ secretion rate was found.

CONCLUSION

Fewer significant differences in PG saliva analytes >12 months after IMRT indicate good functional recovery. Residual xerostomia after IMRT will only be further reduced by addressing the sparing of subsites of the PG or other salivary gland tissues, in addition to the PG.

Abstract A69: The dietary inflammatory index is associated with inflammatory biomarkers among a population of African Americans from South Carolina

Chronic, systemic inflammation is mechanistically involved in processes associated with most major chronic diseases. The Dietary Inflammatory Index (DII) was developed to measure diet-based inflammatory potential, a strong risk factor for systemic inflammation. Participants included those attending baseline measurement clinics for the Healthy Eating and Active Living in the Spirit (HEALS) educational and behavioral intervention (2009-2012). HEALS, a randomized control trial set in faith-based communities, enrolled African Americans (AA) at high risk of chronic inflammation and related diseases. Baseline data were utilized for these analyses. Prior to each clinic visit, participants completed a questionnaire packet to assess demographic characteristics, physical activity, sleep habits (Pittsburgh Sleep Quality Index), health history, depression/stress, and social desirability, approval, and support. Dietary data were collected using a 144-item food frequency questionnaire (FFQ) which was modified based on the Block/NCI instrument. Dietary data from this FFQ, processed using the Nutrient Data System for Research (version 2012, Nutrition Coordinating Center, University of Minnesota, Minneapolis, Minnesota) was used to compute the DII. The DII is comprised of various micro and macronutrients, as well as several individual food items (collectively termed ‘food parameters’); each of which has an inflammatory effect score based on research from 1,943 diet and inflammation research articles. A “world” database (11 populations from around the world) consisting of means and standard deviations for the food parameters was subtracted from an individual's actual dietary intake and divided by its standard deviation, creating a z-score, which were centered around 0 and multiplied by the inflammatory effect score. These were summed across all parameters to create the overall DII score, which were categorized into quartiles. During clinic visits, participants had their blood pressure, height, weight, and percent body fat (via bioelectrical impedance assessment) measured. Physical activity levels were measured using Bodymedia's SenseWear® physical activity armband monitors. Blood samples were collected to characterize inflammatory biomarkers (i.e., high-sensitivity c-reactive protein [CRP] and interleukin-6 [IL-6]). In addition to using quantile regression for the main analyses, logistic regression was utilized when CRP was categorized as ≤3.0mg/L vs. >3.0mg/L. The population was middle-aged (average = 56.9±11.3 years), obese (mean BMI=32.6±6.9kg/m2) and primarily female (80%). Various population characteristics were described according to DII quartiles. Higher DII values were associated with younger age, being married or living with a partner, being employed fulltime, and having a higher BMI. Quantile regression was used to estimate the adjusted 25th, 75th, and 90th percentiles of both CRP and IL-6. The 75th and 90th percentiles of CRP for the fourth quartile of the DII were significantly greater than for the first DII quartile (β0.75=3.95, 95% confidence interval [95%CI]=1.71-6.19; β0.90=6.83, 95%CI=1.11-12.55). No significant findings were observed for IL-6. Logistic regression analyses agreed with the quantile regression results for CRP. Those in DII quartile 4 had 3.17 times (95%CI=1.52-6.62) the odds of having CRP values greater than 3.0mg/L compared to those in DII quartile 1. This is the first construct validation of the DII in an all AA population. Chronic inflammation is a risk factor for many major chronic diseases, diseases that AA suffer from disproportionately. Therefore, the DII may serve as a useful tool to track dietary inflammatory potential among AA populations, which, in turn, may reduce risk of chronic disease among these populations.

Citation Format: Michael Wirth, Nitin Shivappa, Lisa Davis, Thomas Hurley, Andrew Ortaglia, Ruby Drayton, Steven Blair, James Hebert. The dietary inflammatory index is associated with inflammatory biomarkers among a population of African Americans from South Carolina. [abstract]. In: Proceedings of the Eighth AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 13-16, 2015; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2016;25(3 Suppl):Abstract nr A69.

Abstract POSTER-BIOL-1309: Beta-catenin regulated ALDH1A1 is a target in ovarian cancer stem cells

Spheroids are 3D multi-cell aggregates formed in non-adherent culture conditions. In ovarian cancer (OC), they serve as a vehicle for cancer cell dissemination in the peritoneal cavity and protect cells from extracellular stress-induced anoikis. We hypothesized that spheroids are enriched in cancer stem cells and investigated pathways activated under these conditions. Affymetrix-based gene expression profiling of OC cells grown as spheroids vs. monolayers identified β-catenin pathway being upregulated in 3D cultures. Increased expression of β-catenin and target genes (cyclin D1, c-myc) was demonstrated in spheroids vs. monolayers and in successive spheroid generations using OC cell lines and primary cultures. B-catenin function measured as TCF/LEF1 reporter activity was augmented in spheroids vs. monolayers and siRNA mediated β-catenin knock down decreased the number of spheroids (p<0.001). Along with β-catenin, the expression level of ALDH1A1, an OC stem cell marker, was increased in successive spheroid generations. The percentage of ALDH+ cells was significantly higher in spheroids vs. monolayers in IGROV1, A2780, SKOV3, and primary OC cells. B-catenin knock-down decreased ALDH1A1 expression, suggesting that it is a β-catenin target. The percentage of ALDH+ cells and the number of spheroids formed were increased in the cell population dissociated from OC xenografts treated with carboplatin compared to control (44% vs. 2.3%), supporting that ALDH1A1 is a stem cell marker. A37 is a novel ALDH1A1 enzymatic inhibitor (Ki of 5nM). A37 decreased cell viability and spheroid formation by IGROV1 cells (p<0.001). A37 also decreased the percentage of ALDH+ cells under 3D culture conditions. These data support the role of β-catenin regulated ALDH1A1 in the maintenance of OC spheroids and of a stem cell phenotype and propose new ALDH1A1 inhibitors targeting this cell population.

(Funding: US Department of Veterans Affairs and Ovarian Cancer Research Fund)

Citation Format: Salvatore Condello, Sarbajeet Nagdas, Cynthia Morgan, John Turek, Thomas Hurley, Daniela Matei. Beta-catenin regulated ALDH1A1 is a target in ovarian cancer stem cells [abstract]. In: Proceedings of the 10th Biennial Ovarian Cancer Research Symposium; Sep 8-9, 2014; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(16 Suppl):Abstract nr POSTER-BIOL-1309.

A farmers' market at a federally qualified health center improves fruit and vegetable intake among low-income diabetics

OBJECTIVE

A 22-week federally qualified health center (FQHC)-based farmers' market (FM) and personal financial incentive intervention designed to improve access to and consumption of fruits and vegetables (FVs) among low-income diabetics in rural South Carolina was evaluated.

METHODS

A mixed methods, one-group, repeated-measures design was used. Data were collected in 2011 before (May/June), during (August), and after (November) the intervention with 41 diabetes patients from the FQHC. FV consumption was assessed using a validated National Cancer Institute FV screener modified to include FV sold at the FM. Sales receipts were recorded for all FM transactions. A mixed-model, repeated measures analysis of variance was used to assess intervention effects on FV consumption. Predictors of changes in FV consumption were examined using logistic regression.

RESULTS

A marginally significant (p=0.07) average increase of 1.6 servings of total FV consumption per day occurred. The odds of achieving significant improvements in FV consumption increased for diabetics using financial incentives for payment at the FM (OR: 38.8, 95% CI: 3.4-449.6) and for those frequenting the FM more often (OR: 2.1, 95% CI: 1.1-4.0).

CONCLUSIONS

Results reveal a dose-response relationship between the intervention and FV improvements and emphasize the importance of addressing economic barriers to food access.

Reducing cancer disparities through innovative partnerships: a collaboration of the South Carolina Cancer Prevention and Control Research Network and Federally Qualified Health Centers

The South Carolina Cancer Prevention and Control Research Network, in partnership with the South Carolina Primary Health Care Association, and Federally Qualified Health Centers (FQHCs), aims to promote evidence-based cancer interventions in community-based primary care settings. Partnership activities include (1) examining FQHCs' readiness and capacity for conducting research, (2) developing a cancer-focused data sharing network, and (3) integrating a farmers' market within an FQHC. These activities identify unique opportunities for public health and primary care collaborations.

Walking outside Improves Mood for Healthy Postmenopausal Women

Background

Exercise has been shown to decrease breast cancer risk and slow the progression of breast cancer. Physician recommendations and clinical research data most often are for gym-based exercise programs. However, the importance of exercise location on mood and stress hormones that may influence adherence to exercise has not been addressed.

Methods

Women first walked for an hour outdoors along a university path and then a week later, for an hour indoors on a treadmill in a typical gym environment. Pre and post outdoor and indoor exercise moods (happy, pleased, sad, frustrated, worried, angry, delighted, and joy) were assessed by a 6 point Likert questionnaire, and saliva samples were collected for analysis of cortisol, and alpha amylase (a surrogate for serum norepinephrine).

Results

Nineteen healthy, non-smoking, postmenopausal women (average age 58 ± 4) participated. Compared with scores after walking outdoors, walking indoors was associated with higher scores of worry (p = 0.02; mean difference 0.9; 95% CI (0.17, 1.6) and frustration (p = 0.03; mean difference 0.9; 95% CI (0.12, 1.6), and lower scores for feelings of being pleased (p = 0.03; mean difference -0.8; 95% CI: -1.7, 0.1) and delighted (p = 0.05; mean difference -0.9; 95% CI: -1.75, -0.02). Changes in salivary hormone levels did not vary significantly between the two environments.

Conclusion

Walking outdoors was associated with improved mood, but walking indoors was not. Improved mood may reduce breast cancer risk indirectly by promoting regular exercise. Physician recommendations for exercise should include gym and non-gym based exercise options.

Prenatal diagnosis by amniocentesis and chorionic villus biopsy of mtDNA mutation 8993T > G

The mtDNA mutation 8993T > G is associated with neurogenic muscle weakness, ataxia and retinitis pigmentosa (NARP) and Leigh syndrome. There are few reported cases of prenatal testing for mtDNA disorders. Specifically for 8993T > G, there are six cases in which prenatal diagnosis has been reported. We describe prenatal diagnosis in a 36-year-old G3P1 woman with 33% heteroplasmy in white blood cells. She had a previous child who died from Leigh disease (92% heteroplasmy). She underwent prenatal testing by both CVS and amniocentesis of the 8993T > G heteroplasmy levels. This is the first reported case in which both procedures were used. Heteroplasmy was similar in both tissues (58.6% CVS and 55% amniocentesis), in support of the theory that this testing is reliable and may be considered in prenatal cases where this mutation is known in the mother. To date, her child is 20 months old and developing normally. Heteroplasmy determination in the child was refused. Although the infant is developmentally normal, consistent with the observation that levels of heteroplasmy below 60% are compatible with a mild phenotype, this conclusion must be tempered by the limited period of observation and the fact that patients with the NARP phenotype often present later than 20 months of age.

Suicide gene therapy: conversion of ethanol to acetaldehyde mediated by human beta 2 alcohol dehydrogenase

Acetaldehyde (AcH) produced in the physiological metabolism of ethanol can be potentially toxic and immunomodulating. The antitumour activity of a suicide gene system using adenovirus delivered alcohol dehydrogenase (ADH) to convert ethanol to acetaldehyde inside cancer cells has been investigated in vitro and in vivo. In vitro experiments confirmed the toxicity of acetaldehyde to a number of tumour cell lines. Daudi lymphoma cells grown in normal media increased by Day 4 to 650% of their starting number, while those exposed to 250 microM, 500 microM and 1 mM acetaldehyde reached 138, 30 and 5% respectively. Adenocarcinoma cells appeared to be less sensitive with CMT-64 cells and HeLa cells numbering 105 and 53% of their starting number by Day 4 with 1 mM acetaldehyde. After transduction with an adenovirus containing the human ADH beta 2 cDNA, CMT-64 cells exposed to 20 mM ethanol had a reduction in number to 74% by Day 2 and to 36% by Day 4. In a preclinical model with Ad-ADH CMT-64 cells, mice exposed to daily pulses of ethanol for 5 days formed tumours only 30% on Day 6 and 42% on Day 13 of the volume of those in mice exposed to water. The ability of this easily administered suicide gene system to produce significant effects on cell proliferation in vivo suggests that further optimized development is warranted.

Thrombin generation after the abrupt cessation of intravenous unfractionated heparin among patients with acute coronary syndromes: potential mechanisms for heightened prothrombotic potential

OBJECTIVES

The purpose of this study was to determine the mechanistic basis for thrombin generation and increased prothrombotic potential after the abrupt cessation of intravenous (i.v.) unfractionated heparin among patients with acute coronary syndromes.

BACKGROUND

A "rebound" increase in prothrombotic potential has been observed biochemically and clinically after the abrupt cessation of unfractionated heparin (UFH) among patients with acute coronary syndromes. Although the mechanism is unknown, tissue factor and the extrinsic coagulation cascade, both operative in atherosclerotic vascular disease and arterial thrombosis, are thought to be centrally involved.

METHODS

In a single-center, pilot study, 30 patients with either unstable angina or non-ST segment elevation myocardial infarction who had received a continuous i.v. infusion of UFH for 48 h were randomly assigned to: 1) abrupt cessation, 2) i.v. weaning over 12 h or 3) subcutaneous weaning over 12 h.

RESULTS

Thrombin generation (prothrombin fragment 1.2) was evident within 1 h of UFH cessation, increased progressively (by nearly two-fold) at 24 h (p = 0.002) and correlated inversely with tissue factor pathway inhibitor concentration (r = -0.61). Thrombin generation was greatest among patients randomized to abrupt cessation (1.6-fold increase at 24 h) and least in those with i.v. weaning.

CONCLUSIONS

Thrombin generation after the abrupt cessation of UFH may represent a drug-induced impairment of physiologic vascular thromboresistance in response to locally generated tissue factor. A dosing strategy of abbreviated i.v. weaning attenuates but does not prevent heparin rebound among patients with acute coronary syndromes.

A randomized, multicenter trial of weight-adjusted intravenous heparin dose titration and point-of-care coagulation monitoring in hospitalized patients with active thromboembolic disease. Antithrombotic Therapy Consortium Investigators

BACKGROUND

Therapy with intravenous unfractionated heparin improves clinical outcome in patients with active thromboembolic disease, but achieving and maintaining a therapeutic level of anticoagulation remains a major challenge for clinicians.

METHODS

A total of 113 patients requiring heparin for at least 48 hours were randomly assigned at 7 medical centers to either weight-adjusted or non-weight-adjusted dose titration. They were separately assigned to either laboratory-based or point-of-care (bedside) coagulation monitoring.

RESULTS

Weight-adjusted heparin dosing yielded a higher mean activated partial thromboplastin time (aPTT) value 6 hours after treatment initiation than non-weight-adjusted dosing (99.9 vs 78.8 seconds; P =.002) and reduced the time required to exceed a minimum threshold (aPTT >45 seconds) of anticoagulation (10.5 vs 8.6 hours; P =.002). Point-of-care coagulation monitoring significantly reduced the time from blood sample acquisition to a heparin infusion adjustment (0.4 vs 1.6 hours; P <.0001) and to reach the therapeutic aPTT range (51 to 80 seconds) (16.1 vs 19.4 hours; P =.24) compared with laboratory monitoring. Although a majority of patients participating in the study surpassed the minimum threshold of anticoagulation within the first 12 hours and reached the target aPTT within 24 hours, maintaining the aPTT within the therapeutic range was relatively uncommon (on average 30% of the overall study period) and did not differ between treatment or monitoring strategies.

CONCLUSIONS

Weight-adjusted heparin dosing according to a standardized titration nomogram combined with point-of-care coagulation monitoring using the BMC Coaguchek Plus System represents an effective and widely generalizable strategy for managing patients with thromboembolic disease that fosters the rapid achievement of a desired range of anticoagulation. Additional work is needed, however, to improve on existing patient-specific strategies that can more effectively sustain a therapeutic state of anticoagulation.

Mammography use among sociodemographically diverse women: the accuracy of self-report

OBJECTIVE

This study sought to determine the accuracy of self-report of mammography experience among 392 ethnically diverse women aged 50 to 74.

METHODS

Subjects were randomized to the telephone or mail condition and surveyed.

RESULTS

Thirty-one percent of women reported accurately the exact month and year of their most recent mammogram; 54% reported accurately within +/- 3 months, and 83% reported accurately within the year. Greater accuracy was associated with exam recency, White race, and non-Hispanic ethnicity, but not with age, education, or income. Most women could correctly report the reason for, the findings of, and the payor of their mammograms but knew little about how much they or their insurance paid.

CONCLUSIONS

For population surveillance of mammography in the past year, self-report data are generally valid. However, clinical studies requiring more precise dates must use such data with caution. The telephone method, as compared with mail, appears to be a better option for some variables.

Methodological issues for health-related surveys of multicultural older women

Given concerns about survey nonresponse bias as well as the need to plan resources for participant recruitment, this study tracked each step of the recruitment process (location, response, consent, and completion) of sociodemographically diverse older women for a survey concerning mammography experience. Younger, less educated poor women were likely to be lost due to inability to locate them, while older middle- and upper-economic-group women were more likely to be lost due to refusal to participate. Hispanic and Black women were significantly more likely to respond on successive attempts to recruit them than were White, non-Hispanic women. There was no significant difference in refusal rates by minority women over the successive contacts, as contrasted with White women, who refused at significantly higher rates with each attempt.

Antibodies directed against human liver specific membrane lipoprotein (LSP) in marmosets experimentally infected with the hepatitis A virus

Autoantibodies directed against liver plasma membrane antigens have recently been described in patients with acute viral hepatitis, type A (AVH-A). To further investigate this phenomenon, the antibody against one such liver membrane antigen, liver specific membrane lipoprotein (LSP), was assayed in six marmosets orally inoculated with hepatitis A virus (HAV). Using a sensitive radioimmunoassay technique, anti-human LSP antibodies were detected in five of six animals. Two peaks of 125I-HLSP binding were observed: a minor peak at 20 days post-inoculation (dpi) in two animals, and a major peak at 38-45 dpi in five animals. There was no correlation between 125I-HLSP binding and liver histology score, ALT level, IgG concentration, anti-HAV P/N ratio, or E rosette lymphocyte count. A statistically significant correlation was observed, however, between 125I-HLSP binding and IgM anti-HAV antibody P/N ratios. 125I-HLSP binding was blocked by both marmoset and human LSP, but not by a marmoset kidney protein prepared in an identical manner. In summary, marmosets infected with HAV are a suitable animal model for the further investigation of anti-LSP autoantibody formation in AVH-A.

Development of a heterologous radioimmunoassay for somatomedin C in sheep blood

A heterologous radioimmunoassay for the measurement of somatomedin C in sheep serum has been developed using purified 125I-labelled human somatomedin C and an antiserum to human somatomedin C. It was observed that the GH dependence of somatomedin C could not be verified when unprocessed sheep sera were assayed, because of interference by somatomedin binding proteins. After incubation of samples at pH 3.8, however, concentrations of somatomedin C mirrored GH status. Assays results from sera after prolonged exposure to acid agreed with results from which had undergone acidification and gel chromatography. Using the methods developed in this study, 12 sera from normal sheep had a mean concentration of somatomedin C of 2.35 +/- 0.27 (S.E.M.) units/ml while nine sera from hypophysectomized sheep contained 0.45 +/- 0.04 units/ml (P less than 0.001), and one serum from a ewe with a prolonged GH excess associated with a pituitary tumour had a value of 6.9 units/ml. The radioimmunoassay resulting from these studies should provide a tool for investigation of the physiological control of somatomedin C in sheep.

Effects of high dose busulphan on leukaemic progenitor cells in chronic myeloid leukaemia

Six patients with Philadelphia positive chronic myeloid leukaemia (CML) were treated with single high doses of busulphan. The action of busulphan on the in vivo kinetics of circulating progenitor cells (colony forming cells) was measured using an agar culture system which involved scoring of total colonies and clusters at 7 days and of granulocyte, monocyte and eosinophil colonies at 14 days. High dose busulphan was found to be effective in suppressing circulating granulocyte, monocyte and eosinophil progenitor cells. The effect of busulphan on progenitor cells was rapid and their levels fell by at least 85% within five days. By contrast, the white blood cells fell by only 9% and the platelets fell by 10% over this time. Subsequently, the white cell count and platelet count fell to near normal levels. The progenitor cell levels began to rise again at a mean of 35 days following busulphan treatment and the white blood cells at a mean of 39 days in four patients. One patient remained in haematological remission for six months following 100 mg of busulphan with less than 1 progenitor per 5 x 10(5) peripheral blood nucleated cells. One patient in myeloblastic transformation had a previously not described culture pattern consisting of a high cluster to colony ratio at 7 days and of an increased number of predominantly eosinophilic colonies at 14 days. There was no significant fall in progenitor cell levels following busulphan and this patient died.

Simple adaptation of the Technicon SMAC system to operate 18 channels with reduced volumes of plasma

The Technicon SMAC system was adapted to function with much smaller volumes of plasma than those used in standard procedures. With only minimal operator-entered changes to the 7.6 computer program, and simple modifications of the glucose and alkaline phosphatase channels, the SMAC analyser performed equally well when the plasma volume was decreased from 235 microliter sequentially down through 176 microliter, 142 microliter, and 105 microliter. The basic principle employed was to maintain a constant flow rate of diluted sample plus diluent with decreasing sample size. The instrument proved to have the capability of operating successfully on all channels with lower signals than those encountered with the unmodified system.

Failure of bromocriptine, dopamine, and thyrotropin-releasing hormone to affect prolactin secretion by human decidual tissue in vitro

To determine whether the secretion of PRL by human decidual tissue in vitro is influenced by factors which inhibit or stimulate pituitary PRL secretion, explants of decidual tissue were incubated in media containing bromocriptine, dopamine, or TRH at concentrations known to affect pituitary PRL secretion in vitro. The quantities of PRL secreted by the explants exposed to these factors were compared with amounts secreted by explants incubated in control medium. Bromocriptine in concentrations ranging from 1.5 x 10(-10) to 1.5 x 10(-7) M did not inhibit PRL secretion over a 3-day period and dopamine in concentrations ranging from 5 x 10(-5)-10(-9) M did not inhibit PRL secretion over a 4-h period. TRH in concentrations ranging from 10(-9)-10(-3) M did not stimulate PRL secretion. These results suggest that the mechanism of PRL secretion by decidual tissue in vitro is different, at least in part, from the mechanism of pituitary PRL secretion.

Synthesis of prolactin by human decidua in vitro

To determine whether human decidua and/or chorion synthesizes and secretes prolactin, explants of decidua obtained at Caesarian section and explants of chorion from the membranes separating dizygotic twins were cultured for periods of up to 6 days. The decidual explants released 366 +/- 37 ng prolactin/100 mg tissue (mean +/- S.D.) during each day in culture and incorporated 3H-labelled amino acids into immunoprecipitable prolactin. In the radioimmunoassay for prolactin, serial dilutions of incubation medium displaced 125I-labelled prolactin parallel to the displacement by pituitary prolactin and the prolactin in the medium eluted from Sephadex G-150 in a position indentical to that of pituitary prolactin. Chorionic explants released prolactin into the incubation medium during day 1 of culture only and did not incorporate 3H-labelled amino acids into prolactin. These results demonstrate that prolactin is synthesized by the decidua and not by the chorion and suggest that the decidua is the source of prolactin in amniotic fluid.

Prolactin synthesis by human chorion-decidual tissue: a possible source of prolactin in the amniotic fluid

Explants of human chorion-decidual tissue obtained at delivery from normal, full-term pregnancies synthesize and secrete prolactin. This hormone is indistinguishable from pituitary prolactin by chromatographic, electrophoretic, immunologic, and receptor assay techniques. These results suggest that chorion-decidua may be the source of the large quantities of prolactin in amniotic fluid.

Ovine placental lactogen: acute effects on intermediary metabolism in pregnant and non-pregnant sheep

The intravenous administration of ovine placental lactogen to pregnant and non-pregnant sheep produced significant acute decreases in plasma free fatty acid, glucose and amino nitrogen concentrations. Plasma insulin concentrations decreased 1 h after administration of ovine placental lactogen and then increased significantly above baseline concentrations. The results suggest that, like human placental lactogen, ovine placental lactogen is important in the modulation of intermediary metabolism during pregnancy. The sheep is an excellent animal model for the investigation of the physiology of placental lactogen.

Development of the sheep as an animal model to study placental lactogen physiology

Ovine placental lactogen, purified from term sheep cotyledons, has been found to have chemical and biologic properties similar to those of human placental lactogen, ovine growth hormone, and ovine prolactin. OPL stimulates lactation in vivo and in vitro and binds to prolactin and growth hormone membrane receptors. Its binding to growth hormone receptors is approximately 20 times greater than that of hPL, suggesting that its somatotrophic potency is greater than that of hPL. Preliminary in vivo studies in the sheep indicate that oPL affects maternal carbohydrate, lipid, and protein metabolism and that its effects are, in part, similar to those of hPL and growth hormone.