Conformational alteration in glycan induces phospholipase Cβ1 activation and angiogenesis

BACKGROUND

In endothelial cells, phospholipase C (PLC) β1-activated Ca²⁺ is a crucial second messenger for the signaling pathways governing angiogenesis. PLCβ1 is inactivated by complexing with an intracellular protein called translin-associated factor X (TRAX). This study demonstrates specific interactions between Globo H ceramide (GHCer) and TRAX, which highlight a new angiogenic control through PLCβ1 activation.

METHODS

Globo-series glycosphingolipids (GSLs), including GHCer and stage-specific embryonic antigen-3 ceramide (SSEA3Cer), were analyzed using enzyme-linked immunosorbent assay (ELISA) and Biacore for their binding with TRAX. Angiogenic activities of GSLs in human umbilical vein endothelial cells (HUVECs) were evaluated. Molecular dynamics (MD) simulation was used to study conformations of GSLs and their molecular interactions with TRAX. Fluorescence resonance energy transfer (FRET) analysis of HUVECs by confocal microscopy was used to validate the release of PLCβ1 from TRAX. Furthermore, the in vivo angiogenic activity of extracellular vesicles (EVs) containing GHCer was confirmed using subcutaneous Matrigel plug assay in mice.

RESULTS

The results of ELISA and Biacore analysis showed a stable complex between recombinant TRAX and synthetic GHCer with KD of 40.9 nM. In contrast, SSEA3Cer lacking a fucose residue of GHCer at the terminal showed ~ 1000-fold decrease in the binding affinity. These results were consistent with their angiogenic activities in HUVECs. The MD simulation indicated that TRAX interacted with the glycan moiety of GHCer at amino acid Q223, Q219, L142, S141, and E216. At equilibrium the stable complex maintained 4.6 ± 1.3 H-bonds. TRAX containing double mutations with Q223A and Q219A lost its ability to interact with GHCer in both MD simulation and Biacore assays. Removal of the terminal fucose from GHCer to become SSEA3Cer resulted in decreased H-bonding to 1.2 ± 1.0 by the MD simulation. Such specific H-bonding was due to the conformational alteration in the whole glycan which was affected by the presence or absence of the fucose moiety. In addition, ELISA, Biacore, and in-cell FRET assays confirmed the competition between GHCer and PLCβ1 for binding to TRAX. Furthermore, the Matrigel plug assay showed robust vessel formation in the plug containing tumor-secreted EVs or synthetic GHCer, but not in the plug with SSEA3Cer. The FRET analysis also indicated the disruption of colocalization of TRAX and PLCβ1 in cells by GHCer derived from EVs.

CONCLUSIONS

Overall, the fucose residue in GHCer dictated the glycan conformation for its complexing with TRAX to release TRAX-sequestered PLCβ1, leading to Ca²⁺ mobilization in endothelial cells and enhancing angiogenesis in tumor microenvironments.

Estimating infant upper extremities motion with an RGB-D camera and markerless deep neural network tracking: A validation study

Quantitative biomarkers of infant motion may be predictive of the development of movement disorders. This study presents and validates a low cost, markerless motion tracking method for the estimation of upper body kinematics of infants from which proper biomarkers may be extracted. The method requires a single RGB-D camera, a 2D motion tracking software publicly available (DeepLabCut) and an algorithm generating 3D point coordinates from the 2D tracked points, dealing with missing data, originating from various sources, for estimating joint kinematics. The proposed method is validated using known point kinematics obtained from a doll, with size and shape of an infant, lying on a turntable rotating at 33⅓ rpm. Two camera image plane orientations are tested: parallel to the turntable motion plane and forming a 45° angle with respect to the motion plane. The latter enhances the occurrence of body parts occlusions during motion as expected in live infant motion recordings. The length of upper body segments, elbow and shoulder joint angles and the linear point velocity determined with the proposed method are evaluated against reference values obtained from the known motion of the turntable. The relevant Mean Absolute Errors (MAE) found indicate the margin of error to expect when processing live infant motion. The proposed method may be improved if enhanced hardware and tracking software are employed, therefore reducing the above-mentioned margin of error. Clinical Relevance - The validation of the proposed method carried out in this study allows clinicians to select proper quantitative biomarkers obtained from infants upper body motion that may be useful for predicting movement disorders.

P4414Effects of lorcaserin on the cardiometabolic risk factors in overweight or obese patients: a systematic review and meta-analysis

Introduction

Lorcaserin is a selective serotonin 2c receptor agonist approved as an anti-obesity agent. The additional cardiometabolic benefits associated with lorcaserin have not been conclusively established.

Purpose

To examine the effects of lorcaserin on blood pressure, heart rate and other metabolic parameters in overweight or obese patients from randomized controlled clinical trials (RCTs).

Methods

A literature search was conducted on PubMed, EMBASE, and Cochrane Central using search terms: “lorcaserin”, “Belviq”, and “randomized controlled trials” without language restrictions. RCTs with a follow-up period of at least 24 weeks were included for the meta-analysis.

Results

Five studies with 9349 patients in the lorcaserin group and 9370 patients in the placebo group were included. Compared with placebo, lorcaserin not only reduced weight (mean difference [MD] = −3.03 kg, 95% CI: −3.42, −2.63, P<0.ehz745.08171, I2 =68%), waist circumference (MD=−2.27 cm, 95% CI: −2.71, −1.83, P<0.ehz745.08171, I2=57%) and BMI (MD=−1.11 kg/m2, 95% CI: −1.27, −0.96, P<0.ehz745.08171, I2=68%), but also improved SBP (MD=−0.75 mmHg, 95% CI: −1.12, −0.38, P<0.0001, I2=0%), DBP (MD=−0.70 mmHg, 95% CI: −0.93, −0.48, P<0.ehz745.08171, I2=0%), heart rate (MD=−0.94 bpm, 95% CI: −1.28, −0.60, P<0.ehz745.08171, I2=0%), LDL (MD=−1.47 mg/dL, 95% CI: −2.21, −0.74, P<0.0001, I2=0%), HDL (MD=0.55 mg/dL, 95% CI: 0.08, 1.01, P=0.02, I2=18%), triglycerides (MD=−8.71 mg/dL, 95% CI: −12.14, −5.28, P<0.ehz745.08171, I2=71%), and fasting plasma glucose (MD=−5.69 mg/L, 95% CI: −9.5, −1.87, P=0.003, I2=93%). Our findings support that lorcaserin has consistent and favourable effects on blood pressure, heart rate, and all criteria of metabolic syndrome.

Summary of lorcaserin effects

Conclusion

Lorcaserin improved all cardiometabolic parameters modestly in addition to its weight loss effect in overweight or obese patients. More research is needed to determine its long-term cardiovascular benefits.

High expression FUT1 and B3GALT5 is an independent predictor of postoperative recurrence and survival in hepatocellular carcinoma

Cancer may arise from dedifferentiation of mature cells or maturation-arrested stem cells. Previously we reported that definitive endoderm from which liver was derived, expressed Globo H, SSEA-3 and SSEA-4. In this study, we examined the expression of their biosynthetic enzymes, FUT1, FUT2, B3GALT5 and ST3GAL2, in 135 hepatocellular carcinoma (HCC) tissues by qRT-PCR. High expression of either FUT1 or B3GALT5 was significantly associated with advanced stages and poor outcome. Kaplan Meier survival analysis showed significantly shorter relapse-free survival (RFS) for those with high expression of either FUT1 or B3GALT5 (P = 0.024 and 0.001, respectively) and shorter overall survival (OS) for those with high expression of B3GALT5 (P = 0.017). Combination of FUT1 and B3GALT5 revealed that high expression of both genes had poorer RFS and OS than the others (P < 0.001). Moreover, multivariable Cox regression analysis identified the combination of B3GALT5 and FUT1 as an independent predictor for RFS (HR: 2.370, 95% CI: 1.505-3.731, P < 0.001) and OS (HR: 2.153, 95% CI: 1.188-3.902, P = 0.012) in HCC. In addition, the presence of Globo H, SSEA-3 and SSEA-4 in some HCC tissues and their absence in normal liver was established by immunohistochemistry staining and mass spectrometric analysis.

Chimeras of p14ARF and p16: functional hybrids with the ability to arrest growth

The INK4A locus codes for two independent tumor suppressors, p14ARF and p16/CDKN2A, and is frequently mutated in many cancers. Here we report a novel deletion/substitution from CC to T in the shared exon 2 of p14ARF/p16 in a melanoma cell line. This mutation aligns the reading frames of p14ARF and p16 mid-transcript, producing one protein which is half p14ARF and half p16, chimera ARF (chARF), and another which is half p16 and half non-p14ARF/non-p16 amino acids, p16-Alternate Carboxyl Terminal (p16-ACT). In an effort to understand the cellular impact of this novel mutation and others like it, we expressed the two protein products in a tumor cell line and analyzed common p14ARF and p16 pathways, including the p53/p21 and CDK4/cyclin D1 pathways, as well as the influence of the two proteins on growth and the cell cycle. We report that chARF mimicked wild-type p14ARF by inducing the p53/p21 pathway, inhibiting cell growth through G2/M arrest and maintaining a certain percentage of cells in G1 during nocodazole-induced G2 arrest. chARF also demonstrated p16 activity by binding CDK4. However, rather than preventing cyclin D1 from binding CDK4, chARF stabilized this interaction through p21 which bound CDK4. p16-ACT had no p16-related function as it was unable to inhibit cyclin D1/CDK4 complex formation and was unable to arrest the cell cycle, though it did inhibit colony formation. We conclude that these novel chimeric proteins, which are very similar to predicted p16/p14ARF chimeric proteins found in other primary cancers, result in maintained p14ARF-p53-p21 signaling while p16-dependent CDK4 inhibition is lost.

Upregulation of endocan by Epstein-Barr virus latent membrane protein 1 and its clinical significance in nasopharyngeal carcinoma

Endocan (or called Esm-1) has been shown to have tumorigenic activities and its expression is associated with poor prognosis in various cancers. Latent membrane protein 1 (LMP1) is an Epstein-Barr virus (EBV)-encoded oncoprotein and has been shown to play an important role in the pathogenesis of EBV-associated nasopharyngeal carcinoma (NPC). To further understand the role of LMP1 in the pathogenesis of NPC, microarray analysis of LMP1-regulated genes in epithelial cells was performed. We found that endocan was one of the major cellular genes upregulated by LMP1. This induction of endocan by LMP1 was confirmed in several epithelial cell lines including an NPC cell line. Upregulation of endocan by LMP1 was found to be mediated through the CTAR1 and CTAR2 domains of LMP1 and through the LMP1-activated NF-κB, MEK-ERK and JNK signaling pathways. To study whether endocan was expressed in NPC and whether endocan expression was associated with LMP1 expression in NPC, the expression of endocan and LMP1 in tumor tissues from 42 NPC patients was evaluated by immunohistochemistry. Expression of endocan was found in 52% of NPC specimens. Significant correlation between LMP1 and endocan expression was observed (p<0.0001). Moreover, NPC patients with endocan expression were found to have a shorter survival than NPC patients without endocan expression (p=0.0104, log-rank test). Univariate and Multivariate analyses revealed that endocan was a potential prognostic factor for NPC. Finally, we demonstrated that endocan could stimulate the migration and invasion ability of endothelial cells and this activity of endocan was dependent on the glycan moiety and the phenylalanine-rich region of endocan. Together, these studies not only identify a new molecular marker that may predict the survival of NPC patients but also provide a new insight to the pathogenesis of NPC.

Concordant and discordant regulation of target genes by miR-31 and its isoforms

It has been shown that imprecise cleavage of a primary or precursor RNA by Drosha or Dicer, respectively, may yield a group of microRNA (miRNA) variants designated as "isomiR". Variations in the relative abundance of isoforms for a given miRNA among different species and different cell types beg the question whether these isomiRs might regulate target genes differentially. We compared the capacity of three miR-31 isoforms (miR-31-H, miR-31-P, and miR-31-M), which differ only slightly in their 5'- and/or 3'-end sequences, to regulate several known targets and a predicted target, Dicer. Notably, we found isomiR-31s displayed concordant and discordant regulation of 6 known target genes. Furthermore, we validated a predicted target gene, Dicer, to be a novel target of miR-31 but only miR-31-P could directly repress Dicer expression in both MCF-7 breast cancer cells and A549 lung cancer cells, resulting in their enhanced sensitivity to cisplatin, a known attribute of Dicer knockdown. This was further supported by reporter assay using full length 3'-untranslated region (UTR) of Dicer. Our findings not only revealed Dicer to be a direct target of miR-31, but also demonstrated that isomiRs displayed similar and disparate regulation of target genes in cell-based systems. Coupled with the variations in the distribution of isomiRs among different cells or conditions, our findings support the possibility of fine-tuning gene expression by miRNAs.

Abstract 3983: MiR-31 isoforms differentially regulate expression of dicer in cancer cells

MicroRNAs (miRNAs) are a group of small non-coding RNAs involved in several important biological processes. Recent studies have implied that imprecise cleavage of primary or precursor RNA by Drosha or Dicer respectively could produce miRNAs with variations at 5’-and/or 3’-ends, which were termed “isomiR”. The existence of isomiRs may increase the complexity of miRNA biology, although their functions have not been explored. This is further complicated by the observation of variations in the population of isomer for a given miRNA among different species as well as among different types of cells within the same species (human cells), which raises the issue whether these isomers might exert differential effects on target gene regulation. Here, we utilized three miR-31 isoforms (miR-31-H, miR-31-P, and miR-31-M) which differ from each other only slightly in their sequences at both ends, to compare their capacity to regulate a predicted target, Dicer. Interestingly, we found only miR-31-P was able to directly repress Dicer expression in both breast cancer MCF-7 cells and lung cancer A549 cells, resulting in their enhanced sensitivity to cisplatin, which is known to be associated with Dicer knockdown. In line with this, the amount of miR-31-P bound to the RNA-induced silencing complex (RISC) was greater than that of miR-31-H and -M by RNA-CHIP analysis. Furthermore, evaluation of other known miR-31 target genes showed that expression of some target genes was indeed differentially regulated by miR-31 isoforms. Our findings not only revealed Dicer to be a direct target of miR-31, but also demonstrated the disparate functions of isomiRs for the fist time, providing a novel functional mechanism of fine-tuning of gene expression by miRNAs.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3983. doi:10.1158/1538-7445.AM2011-3983

microRNA signature and expression of Dicer and Drosha can predict prognosis and delineate risk groups in neuroblastoma

Neuroblastoma is a common childhood tumor and accounts for 15% of pediatric cancer deaths. To investigate the microRNA (miRNA) profile and role of Dicer and Drosha in neuroblastoma, we assessed the expression of 162 human miRNAs, Dicer and Drosha in 66 neuroblastoma tumors by using real-time PCR methods. We found global downregulation of miRNA expression in advanced neuroblastoma and identified 27 miRNAs that can clearly distinguish low- from high-risk patients. Furthermore, expression levels of Dicer or Drosha were low in high-risk neuroblastoma tumors, which accounted for global downregulation of miRNAs in advanced disease and correlated with poor outcome. Notably, for patients with non-MYCN-amplified tumors, low expression of Dicer can serve as a significant and independent predictor of poor outcome (hazard ratio, 9.6; P = 0.045; n = 52). Using plausible neural networks to select a combination of 15 biomarkers that consist of 12 miRNAs' signature, expression levels of Dicer and Drosha, and age at diagnosis, we were able to segregate all patients into four distinct patterns that were highly predictive of clinical outcome. In vitro studies also showed that knockdown of either Dicer or Drosha promoted the growth of neuroblastoma cell lines. Our results reveal that a combination of 15 biomarkers can delineate risk groups of neuroblastoma and serve as a powerful predictor of clinical outcome. Moreover, our findings of growth promotion by silencing Dicer/Drosha implied their potential use as therapeutic targets for neuroblastoma.

c-Myb is an evolutionary conserved miR-150 target and miR-150/c-Myb interaction is important for embryonic development

Human c-Myb proto-oncogene is highly expressed in hematopoietic progenitors as well as leukemia and certain solid tumor. However, the regulatory mechanisms of its expression and biological functions remain largely unclear. Recently, c-Myb has been shown to be targeted by microRNA-150 (miR-150) which thereby controls B cell differentiation in mice. In this study, we demonstrated that c-Myb is an evolutionary conserved target of miR-150 in human and zebrafish, using reporter assays. Ectopic expression of miR-150 in breast cancer and leukemic cells repressed endogenous c-Myb at both messenger RNA (mRNA) and protein levels. Among several leukemia cell lines, primary leukemia cells, and normal lymphocytes, expression levels of miR-150 inversely correlated with c-Myb. The miR-150 overexpression or c-Myb silencing in zebrafish zygotes led to similar and serious phenotypic defects in zebrafish, and the phenotypic aberrations induced by miR-150 could be reversed by coinjection of c-Myb mRNA. Our findings suggest that c-Myb is an evolutionally conserved target of miR-150 and miR-150/c-Myb interaction is important for embryonic development and possibly oncogenesis.

Human gastric cells resistant to (−)-epigallocatechin gallate show cross-resistance to several environmental pollutants

After a long-term culture in (-)-epigallocatechin gallate (EGCG, 20 microM), a major constituent of green tea, human gastric AGS cells developed 2.2-fold resistance to EGCG. The resistant AGS (AGS-R) cells were cross-resistant to several N-methylcarbamate insecticides, which are among the major control agents for pest insects in Taiwan. The AGS-R cells also showed protective effects against both the cytotoxicity and DNA damage induced by one of the mutagenic derivatives of N-methylcarbamate insecticide, N-nitroso methomyl, which is known to target the mammalian gastric tract. Therefore, acquisition of resistance by AGS cells through chronic exposure to EGCG implies that the tea-drinking habit of the Taiwanese is probably beneficial for the health of the gastric tract. In addition, AGS-R cells were cross-resistant to sodium arsenite and hydrogen peroxide, indicating that tolerance to oxidative stress might play a role in the development of resistance described in this investigation.

Human TRIM71 and its nematode homologue are targets of let-7 microRNA and its zebrafish orthologue is essential for development

Animal microRNAs (miRNAs) are short RNAs that function as posttranscriptional regulators of gene expression by binding to the target mRNAs. Noting that some miRNAs are highly conserved in evolution, we explored the possibility of evolutionary conservation of their targets. We identified human orthologues of experimentally verified let-7 miRNA target genes in Caenorhabditis elegans and used the luciferase reporter system to examine whether these human genes are still the targets of let-7 miRNA. We found that in some cases, the miRNA-target relationship has indeed been conserved in human. Interestingly, human TRIM71, an orthologue of C. elegans let-7-target lin-41 gene, can be repressed by hsa-let-7a and hsa-let-7c. This repression was abolished when both predicted let-7 target sites of TRIM71 were mutated. Moreover, the zebrafish lin-41 orthologue was also repressed by let-7 to a similar degree as was TRIM71. When the expression of zebrafish lin-41 orthologue was silenced by microinjection of RNA interference or morpholino into zebrafish zygotes, retarded embryonic development was observed, providing direct evidence for an essential role of lin-41 in zebrafish development. Taken together, our results suggest that the regulation of TRIM71 expression by let-7 has been evolutionarily conserved and that TRIM71 likely plays an important role in development.

Epstein-barr virus nuclear antigen 2 retards cell growth, induces p21(WAF1) expression, and modulates p53 activity post-translationally

The Epstein-Barr virus (EBV) nuclear antigen 2 (EBNA2) has been shown to be required for promotion of cell-cycle progression in EBV-immortalized B-lymphocytes. However, other studies have indicated that EBNA2 alone, in the absence of other EBV genes, may retard cell growth. To resolve this discrepancy, we investigated the effect of EBNA2 on the growth of various cells, including EBV target nasopharyngeal carcinoma cells, NPC-TW01 and NPC-TW04. We found that EBNA2 could retard cell growth, in stable Vero, HEp-2, and U2OS cell clones expressing EBNA2, and in Vero, 293, NPC-TW01, and NPC-TW04 cells transiently transfected with EBNA2. While investigating the mechanism underlying the growth-retarding function of EBNA2, we found that EBNA2 induced p21(WAF1) expression in these cells. This induction of p21(WAF1) expression was mediated through p53. EBNA2 was found to stimulate p53 to bind to the p53-response element within the p21(WAF1) promoter, possibly by promoting p53 phosphorylation. This enhancement of p53 sequence-specific DNA-binding activity may be the mechanism through which EBNA2 activates the expression of p53-regulated genes, including p21(WAF1) and mdm-2. Together, these studies reveal a possible intrinsic function of EBNA2 in cell-growth regulation and elucidate a novel mechanism by which EBNA2 modulates transcription.

Use of the transurethral prostatectomy clinical path to monitor health outcomes

PURPOSE

We evaluated the effect on cost and medical care quality of use of the transurethral prostatectomy clinical path.

MATERIALS AND METHODS

Results in 100 patients treated when the transurethral prostatectomy clinical path was used were compared to those of 100 treated by the same physicians before implementation of this path.

RESULTS

After implementation of the transurethral prostatectomy clinical path the length of hospital stay was significantly decreased from 5.9 to 5.0 days (p < 0.01) and Foley catheterization time was significantly decreased from 3.13 to 2.84 days (p < 0.01). Antibiotics were routinely used from the day before surgery to the day of hospital discharge as required by patient conditions. Therefore, a shorter hospital stay will significantly decrease the use of antibiotics. After implementation of the clinical path the average admission charges were decreased significantly by 17% (p < 0.01). Although some results from use of this path will not significantly affect costs, they will reflect some quality improvement. The effect of clinical path implementation on length of hospital stay between patients treated by junior and senior attending physicians was not significant. However, there was a statistically significant difference (p < 0.01) between results obtained by junior and senior attending physicians regarding average admission charges.

CONCLUSIONS

Implementation of the transurethral prostatectomy clinical path can improve health care outcome by decreasing length of stay and admission charges, and improving quality of medical care, particularly for patients treated by junior attending physicians.

Complex marital histories and economic well-being: the continuing legacy of divorce and widowhood as the HRS cohort approaches retirement

We use data from the first wave of the Health and Retirement Survey (HRS) to examine the marital histories of this cohort of women and men on the verge of retirement. The legacy of past increases in divorce rates is evident in the complex marital histories of HRS households and the relationship between those histories and current economic status. Couples in a first marriage now make up only one-quarter of black households and fewer than half of all white and Hispanic households. In over one-third of all married-couple households, at least one spouse had a previous marriage that ended in divorce or widowhood. These couples have significantly lower incomes and assets than couples in first marriages. Contrary to the popular notion that private and public insurance better provide for the security of widows than divorced persons, currently widowed households and couples in which the prior marriage of one spouse had ended in widowhood are no better off than are their divorced peers. This holds true for both black and white households. From a single cross-section, one cannot tell what caused these differences in income and wealth across marital status groups although it is clear that women and blacks spend a higher percentage of their lifetime outside of marriage than do men and whites. We also speculate from estimates of widowhood expectations for a subset of married respondents that underestimating the chances of widowhood--because both men and women overestimate their chances of joint survival--may be a factor in the relatively low economic status of widows. Because couples in life-long marriages have been the traditional standard upon which marital property reform and the survivorship rules of private and public programs are based, their diminishing importance among all households raises concern about the protection provided by these institutions against the long-term economic consequences of past and future marital dissolution.

Gender, family configuration, and the effect of family background on educational attainment

A comprehensive model of family influences on educational resemblance of siblings expands the traditional sibling pair model to a full sibship model in order to investigate how gender, gender composition of sibships, and a measure of ordinal position moderate the effect of social origins on educational attainments of siblings. One common family factor is sufficient to explain the variation of educational attainment among brothers and sisters. Although effects of social origins variables on brothers are larger than on sisters, the relative effects of measured social origins are virtually the same among sisters and brothers. The disparity between educational attainments of brothers and sisters persists across sex composition and family size. Ordinal position does not alter the effects of social origins on educational attainment nor does it directly affect educational attainment. Father's and mother's education are equally important for all siblings regardless of birth order, gender composition, and family size.

Preeclampsia in multiple pregnancy

BACKGROUND

Preeclampsia is one of the most common pregnancy-induced complications, and results in a large number of maternal deaths. How pregnancy incites or aggravates hypertension remains unresolved; despite decades of intensive research directed to hypertensive disorders, they remain among the most important unresolved problems in obstetrics. The incidence of preeclampsia is increased in multiple pregnancies, and several preeclampsia-related fetal risks may be particularly hazardous to the babies of multiple gestations.

METHODS

The records of 561 women with multiple pregnancies delivered consecutively at Mackay Memorial Hospital were reviewed retrospectively. Thirteen mild cases and 39 severe cases of preeclampsia in multiple pregnancies were compared with 52 control cases of multiple pregnancies without preeclampsia, but matched for maternal age and parity. The categories for comparison included parity, gestational age, time of onset of preeclampsia, route of delivery, mean birth weight, growth discordancy, maternal complications, neonatal morbidity and mortality.

RESULTS

The incidence of preeclampsia in our consecutive series of 561 multiple pregnancies was 9.3% compared with 1.8% in singleton pregnancies (p < 0.0001). In primiparas with multiple pregnancies, the incidence of preeclampsia was 12.2% compared with 6.2% (p < 0.05) in multiparas. Breech presentation was the most common indication for Cesarean section in all groups. The preeclamptic group had a significantly higher rate of Cesarean section compared with the control group (p < 0.006), with prolonged labor and fetal distress were the two main reasons for this difference. Severe preeclamptic patients had babies with significantly lower mean birth weights (p < 0.05), higher incidence of intrauterine growth retardation (p < 0.025) and neonatal respiratory distress syndrome (p < 0.0008) compared with those of the control group. All seven cases with maternal complications were in the severe preeclamptic group.

CONCLUSIONS

An unfavorable perinatal outcome was found to be associated with severe, but not with mild, preeclampsia in multiple pregnancies.

Determination of free progesterone in an ultrafiltrate of saliva collected in situ

We have investigated the utility of an ultrafiltrate of saliva for measuring progesterone as an indicator of luteal function during the menstrual cycle of women. A filtrate of saliva is collected in the mouth by means of an osmotic pump that accumulates medium containing only molecules less than 12,000 Da. We analyzed the nonextracted ultrafiltrate by a solid-phase immunoassay for progesterone and monitored the mid-luteal surge of lutropin in urine with a liquid-phase radioimmunoassay. Progesterone concentrations in the ultrafiltrate are significantly lower during the follicular phase and increase after the release of lutropin. The concentration of progesterone in the ultrafiltrate correlates closely with total progesterone in matched blood samples (r = 0.84, cycle 1; and r = 0.89, cycle 2). Likewise, we found a good correlation between the results in whole saliva and in the ultrafiltrate (r = 0.95). The described method of obtaining a pre-processed specimen noninvasively simplifies the self-collection of samples by patients (including collection at home); excludes potential interference from microorganisms, desquamated cells, and salivary components; and simplifies the processing of the biological fluid in the laboratory.

Determination of free progesterone in an ultrafiltrate of saliva collected in situ

We have investigated the utility of an ultrafiltrate of saliva for measuring progesterone as an indicator of luteal function during the menstrual cycle of women. A filtrate of saliva is collected in the mouth by means of an osmotic pump that accumulates medium containing only molecules less than 12,000 Da. We analyzed the nonextracted ultrafiltrate by a solid-phase immunoassay for progesterone and monitored the mid-luteal surge of lutropin in urine with a liquid-phase radioimmunoassay. Progesterone concentrations in the ultrafiltrate are significantly lower during the follicular phase and increase after the release of lutropin. The concentration of progesterone in the ultrafiltrate correlates closely with total progesterone in matched blood samples (r = 0.84, cycle 1; and r = 0.89, cycle 2). Likewise, we found a good correlation between the results in whole saliva and in the ultrafiltrate (r = 0.95). The described method of obtaining a pre-processed specimen noninvasively simplifies the self-collection of samples by patients (including collection at home); excludes potential interference from microorganisms, desquamated cells, and salivary components; and simplifies the processing of the biological fluid in the laboratory.

Interferon-mediated inhibition of prostaglandin synthesis in human mononuclear leukocytes

In this study, the question of whether human leukocyte-derived and fibroblast-derived interferon had an effect on prostaglandin metabolism in human peripheral blood mononuclear cells has been considered. Both leukocyte- and fibroblast-derived interferon were potent inhibitors of mononuclear cell prostaglandin synthesis at low physiological concentrations. Inhibition required a minimum incubation of 1 hr. Interferon had no effect on release of arachidonic acid; synthesis of hydroxy fatty acids was slightly increased.

Modulation of T-lymphocyte differentiation antigens: potential relevance for multiple sclerosis

Effects of the anti-T-cell monoclonal antibodies OKT3, OKT5, and OKT8 on T-cell surface properties and cell functions were evaluated. Incubation of mononuclear cells isolated from peripheral blood for 48 hr with each monoclonal antibody in the absence of complement resulted in modulation of their respective surface antigens; i.e., the number of cells detected by immunofluorescence as positive for the T3, T5, and T8 surface antigens was reduced. T3, T5, and T8 antigens modulated independently. A radiolabeled second antibody technique confirmed modulation by OKT3 and OKT8 and indicated that T-cell differentiation antigens can regenerate in culture. Incubation of mononuclear cells with OKT3 increased the number of sheep erythrocyte-binding lymphocytes (E+-rosetting cells) and markedly increased the number of avidly E+-rosetting cells. Incubation with OKT8 reduced the number of E+- and of avidly E+-rosetting cells. OKT3 induced both mitogenic reactivity and suppressor cell activity; cells modulated by OKT8 exhibited reduced mitogenic reactivity and reduced suppressor cell function. The decreases in total T cells, in avid T cells, in suppressor cell number, and in suppressor cell function that follow modulation by OKT8 mimic changes observed in multiple sclerosis patients.

Influence of azathioprine (imuran) on in vitro immune function in multiple sclerosis

In vitro immune function was assessed in patients with multiple sclerosis (MS) who were receiving Imuran therapy, in untreated MS patients, and in controls. In untreated stable MS patients, concanavalin A (Con A)-driven mitogenic reactivity (T effector function) and Con A-induced suppressor activity were modestly reduced compared to controls; pokeweed mitogen-induced immunoglobulin G (IgG) secretion was increased. Untreated patients with active MS demonstrated high levels of IgG secretion and marked decreases in suppressor activity. In Imuran-treated patients, Con A mitogenic responses and suppressor activity were comparable to those observed in untreated stable patients, and IgG secretion was reduced. The results in the treated patients likely reflect a direct effect of Imuran on B cell function rather than an indirect effect mediated via suppressor cells.

Generation of suppressor cells by aggregated human globulin

We have studied the capacity of aggregated human globulin, a model for immune complexes, to induce suppressor cells which modulate a predominantly T cell response, i.e. the proliferative response of autologous mononuclear cells to concanavalin A. We utilized a soluble aggregated human globulin preparation depleted of both high molecular weight (greater than 4 x 10(6) daltons) insoluble aggregates and monomeric IgG. The mean per cent suppression induced by mononuclear cells preincubated with aggregated human globulin for 96 hr was 39 +/- 8%; monomeric IgG did not induce significant suppression (4 +/- 6%). We found a close correlation between the magnitude of suppression induced by preincubation for 96 hr with aggregated human globulin and that induced by preincubation with concanavalin A. Kinetic analysis indicated that suppressor cell induction by aggregated human globulin required 48 hr of preincubation; suppressor cell induction by concanavalin A required 24 hr. Aggregated human globulin-induced suppression was not associated with DNA synthesis as measured by 3H-thymidine uptake. The findings suggest that immune complexes can modulate immunoregulation.

A new solid-phase radioimmunoassay to measure IgG secreted by cultured human lymphocytes

We describe a simple solid-phase radioimmunoassay (RIA) to detect IgG based on competitive binding between radiolabeled and unlabeled IgG for anti-IgG antibody physically adsorbed to the wells of polyvinyl microtiter plates. The assay is sensitive (1 ng), rapid, and is particularly suited for studies of in vitro IgG secretion by human peripheral blood lymphocytes, since such studies require large numbers of cultures. Conditions which permit measurement, by means of this assay, of helper and suppressor T cell effects on IgG production by human B cells in culture are described.