BMP and activin receptor membrane bound inhibitor: BAMBI has multiple roles in gene expression and diseases (Review)

BMP and activin membrane-bound inhibitor (BAMBI) is a transmembrane glycoprotein, known as a pseudo-receptor for TGFβ, as, while its extracellular domain is similar to that of type I TGFβ receptors, its intracellular structure is shorter and lacks a serine/threonine phosphokinase signaling motif. BAMBI can regulate numerous biological phenomena, including glucose and lipid metabolism, inflammatory responses, and cell proliferation and differentiation. Furthermore, abnormal expression of BAMBI at the mRNA and protein levels contributes to various human pathologies, including obesity and cancer. In the present review, the structure of BAMBI is briefly introduced and its associated signaling pathways and physiological functions are described. Understanding of BAMBI structure and function may contribute to knowledge regarding the occurrence of diseases, including obesity and diabetes, among others. The present review provides a theoretical foundation for the development of BAMBI as a potential biomarker or therapeutic target.

C1q/Tumor Necrosis Factor-Related Protein 9: Basics and Therapeutic Potentials

C1q/tumor necrosis factor-related protein 9 (CTRP9) is a newly discovered adipokine that is the closest paralog of adiponectin. Proteolytic cleavage of CTRP9 leads to the release of the globular domain (gCTRP9), which serves as the major circulating subtype. After binding with adiponectin receptor 1 (AdipoR1) and N-cadherin, CTRP9 activates various signaling pathways to regulate glucose and lipid metabolism, vasodilation and cell differentiation. Throughout human development and adult life, CTRP9 controls many biological phenomena. simultaneously, abnormal gene or protein expression of CTRP9 is accompanied by a wide range of human pathological phenomena. In this review, we briefly introduce CTRP9 and its associated signaling pathways and physiological functions, which may be helpful in the understanding of the occurrence of diseases. Moreover, we summarize the broader research prospects of CTRP9 and advances in therapeutic intervention. In recent years, CTRP9 has attracted extensive attention due to its role in the pathogenesis of various diseases, providing further avenues for its exploitation as a potential biomarker or therapeutic target.

Secreted frizzled-related protein 4 promotes brown adipocyte differentiation

Secreted frizzled-related protein 4 (SFRP4) is a member of the SFRP family that contains a cysteine-rich domain homologous to the putative Wnt-binding site of frizzled proteins. In the present report, the effects of SFRP4 on murine brown adipocyte differentiation were evaluated, which exhibited an intrinsic capacity to differentiate with high efficiency. Brown preadipocytes were isolated from the scapular region of brown adipose tissue, which showed that the overexpression of recombinant active SFRP4 protein at three concentrations (1, 10 and 100 ng/ml) significantly increased the expression of adipocyte differentiation-associated genes (C/EBPα, C/EBPβ, UCP-1, PRDM16, PGC1α and GLUT4) in a dose-dependent manner compared with the control group. Secondly, adiponectin protein expression was significantly inhibited in a dose-independent manner, while leptin was increased in brown adipocytes by incubation with the high concentration (100 ng/ml) of SFRP4. Thirdly, the role of interleukin-1β (IL-1β) was investigated in brown adipocytes and discovered that IL-1β cannot induce SFRP4 mRNA expression in brown adipocytes, similar to human islet cells. These data suggested that SFRP4-treated brown adipocytes represent a valuable in vitro model for the study of adipogenesis and indicated that SFRP4 served various functions during brown adipocyte differentiation.

IGFBP5 suppresses oleate-induced intramyocellular lipids deposition and enhances insulin signaling

Excess intramyocellular lipids are often accompanied by muscle insulin resistance (IR) and type 2 diabetes. The mechanism of the formation of intramyocellular lipids is unclear yet. In this study, we optimized the cellular model of intramyocellular lipids from differentiated C2C12 cells and identified that the expression of insulin-like growth factor-binding protein 5 (IGFBP5) is diminished in this process. Then, we added exogenous recombinant IGFBP5 during myocyte triglyceride (TAG) formation and found decreased lipids accumulation. In addition, IGFBP5 could promote lipolysis when added to the cellular model after the formation of intramyocellular lipids. Moreover, IGFBP5 could enhance myocyte insulin sensitivity by inhibiting the expression of the thioredoxin-interacting protein (TXNIP) and arrestin domain-containing 4 (ARRDC4), which are a negative regulator of insulin signaling in both cases. Meanwhile, IGFBP5 also inhibited the expression of glycerol-3-phosphate acyltransferase (GPAM) and diglyceride acyltransferase 2 (DGAT2), which were involved in TAG synthesis from a fatty acid. IGFBP5 also reduced TAG storage by promoting lipolysis. Therefore, IGFBP5 may play a role in the excess accumulation of lipid in muscle cells of diabetic patients and serve as a reference for further research and treatment of muscle IR and diabetes.

Hhip inhibits proliferation and promotes differentiation of adipocytes through suppressing hedgehog signaling pathway

Adipogenesis, which directly control body fat mass, plays a crucial role in lipid metabolism and obesity-related diseases. Hedgehog interacting protein (Hhip) belongs to Hedgehog (Hh) signaling pathway. The Hh signaling pathway was already linked with adipogenesis in previous reports, however, the physiological functions of Hhip on lipid deposition are still poorly understood. In this study, the level of Hhip was down-regulated during the development of porcine adipose tissues. Recombinant Hedgehog interacting protein (rHhip) could down-regulate cell cycle related genes and cell numbers in S phage to inhibit cell proliferation. Moreover, rHhip could increase adipocytes differentiation by targeting canonical Hh signaling, indicated by the increase of lipid accumulation and up-regulation of Glut4 and PPARγ expression. Collectively, these findings illustrated the essential role of Hhip in the proliferation and differentiation of adipocytes, and provided a potential novel target for preventing obesity.

Abstract P4-14-14: Clinicopathological features and endocrine therapy mode of ER low expression (1%-9%) breast cancer patients in China

Purpose: Since 2010, ASCO/CAP recommended that ER be considered positive if ≥1% tumor cells with positive nuclear staining by immunohistochemistry (IHC) in breast cancer. ASCO/CAP also recommended considering endocrine therapy (ET) in ER positive patients. However, most breast cancers are either ER negative or ER strongly positive (≥10%), and tumors with low ER (1-9%) expression are rare. Up to now, the effect of ET is controversial for these patients with ER 1-9% and unfortunately, we know little about the clinical information of this subgroup. In this study, we analyzed the clinicopathological characteristics and ET mode of patients with low ER expression. We sought to figure out whether the ASCO/CAP guidelines affect clinical ET decision in China and Which features are important considerations for doctors to choose ET. We also evaluated the efficacy of ET in these patients. Methods: Patients diagnosed stage I-III primary invasive breast cancer with ER low expression (1-9%) between January 2008 and December 2016 were retrospectively identified from six hospitals in China. Result: 457 patients (2.7%) had low expression of ER (1-9%) of 17216 patients. Mean age at diagnosis was 49 years. 288 patients (49.9%)were younger than 50 years old. 254 patients (55.6%) had stage II disease and 37 patients (8.1%) had lymphovascular invasion (LVI). 260 patients (56.9%) were HER2 positive; 408 patients had PR negative or low expression; 327 patients' (71.6%) Ki-67 status were > 20%. 388 patients (85%) received chemotherapy. Of those 388 patients, 90% patients received anthracycline combined with taxol chemotherapy regimens. 170 patients (37.2%)received ET. Before 2010, only 25.7% patients with low ER expression received ET. The proportion of ET increased after the 2010 ASCO/CAP guideline was published. In 2013, 50% patients received ET. The rate of ET was totally different in six hospitals. 55% patients received ET in the hospital with highest rate, while only 4% patients received ET in the hospital with lowest rate. Using the univariate logistic regression analysis of ET, ER expression, PR expression, Ki-67 status and LVI were associated with the rate of ET. But after adjustment for other covariates, only ER level was significantly associated with the rate of ET. Compared to patients with ER<5% tumors, patients with ER≥5% tumors had a significantly higher probability of ET rate (OR, 2.882; 95% CI: 1.928-4.308; P < 0.001). Median follow time was 30 months. The 5-year RFS rate was 85%. Younger age and positive lymph nodes were associated with worse RFS. Survival rate did not differ significantly between patients with or without ET (without ER vs with ET: OR, 0.870; 95% CI: 0.508-1.448; p=0.61). Conclusions: 2010 ACSO/CAP recommendation indeed result in an increase of ET rate for patients with 1%-9% ER positive. But these patients do not appear to benefit from ET. Prospective studies are needed for these patients and we need more accurate way to evaluate ER levels, which associate with endocrine response.

Citation Format: Fu P, Wang S, Yao M, Xiang A, Li J, Wang H, Geng C, Jin F, Yin Y, Huang X, Jiang Z. Clinicopathological features and endocrine therapy mode of ER low expression (1%-9%) breast cancer patients in China [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-14-14.

Bmal1 interference impairs hormone synthesis and promotes apoptosis in porcine granulosa cells

In mammals, granulosa cell proliferation, differentiation, luteinization, apoptosis, and hormone synthesis are tightly related to oocyte maturation, follicular development and ovarian function. In current study, we investigated the role of the key circadian clock gene, brain and muscle arnt-like protein-1 (Bmal1), on porcine granulosa cell hormone secretion and apoptosis. The transcription levels of circadian clock genes, including Bmal1 and period circadian clock 2 (Per2), were detected by RT-qPCR. We found that the circadian clock genes exhibited rhythmic change and were further enhanced by dexamethasone synchronization in granulosa cells. Bmal1 knockdown reduced transcriptional levels of hormone receptor genes, including follicle stimulating hormone receptor (Fshr), luteinizing hormone/choriogonadotropin receptor (Lhcgr) and estrogen receptor 2 (Esr2), and decreased the mRNA and protein levels of cytochrome P450 family 11 subfamily A member 1 (Cyp11a1), cytochrome P450 family 19 subfamily A member 1 (Cyp19a1) and steroidogenic acute regulatory protein (Star), which are the key enzymes involved in hormone synthesis. Synthesis of progesterone and estradiol were also inhibited by Bmal1 siRNA treatment in granulosa cells. Moreover, flow cytometry analysis demonstrated suppressing Bmal1 promoted granulosa cells apoptosis. Western blot analysis showed that Bmal1 interference inactivated the PI3K/Akt/mTOR signaling pathway. In conclusion, Bmal1 plays a critical role in secretion of hormone and apoptosis of porcine granulosa cells via the PI3K/Akt/mTOR signaling pathway.

Cellular microRNA miR-10a-5p inhibits replication of porcine reproductive and respiratory syndrome virus by targeting the host factor signal recognition particle 14

Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most economically important viruses affecting the swine industry worldwide. MicroRNAs have recently been demonstrated to play vital roles in virus-host interactions. Our previous research on small RNA deep sequencing showed that the expression level of miR-10a increased during the viral life cycle. The present study sought to determine the function of miR-10a and its molecular mechanism during PRRSV infection. In the current study, the result of PRRSV infection inducing miR-10a expression was validated by quantitative reverse transcriptase PCR. Overexpression of miR-10a-5p using its mimics markedly reduced the expression level of intracellular PRRSV ORF7 mRNA and N protein. Simultaneously, overexpression of miR-10a-5p also significantly decreased the expression level of extracellular viral RNA and virus titres in the supernatants. These results demonstrated that miR-10a-5p could suppress the replication of PRRSV. A direct interaction between miR-10a-5p and signal recognition particle 14 (SRP14) was confirmed using bioinformatic prediction and experimental verification. miR-10a-5p could directly target the 3'UTR of pig SRP14 mRNA in a sequence-specific manner and decrease SRP14 expression through translational repression but not mRNA degradation. Further, knockdown of SRP14 by small interfering RNA also inhibits the replication of PRRSV. Collectively, these results suggested that miR-10a-5p inhibits PRRSV replication through suppression of SRP14 expression, which not only provides new insights into virus-host interactions during PRRSV infection but also suggests potential new antiviral strategies against PRRSV infection.

Abstract P2-01-39: Axillary reverse mapping using fluorescence imaging in the surgical treatment for breast cancer patients

Background: Axillary lymph node dissection (ALND) is the standard surgical treatment for breast cancer patients who have axillary nodal metastasis but do not meet the criteria of Z0011 trial. Arm lymphedema is one of the most common and serious complications of ALND. Based on the hypothesis that the lymphatic system of the upper extremity may be separate from that of the breast, the axillary reverse mapping (ARM) technique has been developed to identify the axillary lymph nodes and lymphatics that receive the lymph from the upper limb, and to preserve them during ALND in order to prevent arm lymphedema. However, it is difficult to keep the arm lymphatic system intact because of the lack of full understanding of anatomical variations of the ARM nodes and lymphatics in the axilla, the inconsistency of different ARM techniques in identifying the axillary ARM nodes, and the potentially high rate of ARM nodal metastases in breast cancer patients. The aims of this study was to know (1) the identification rate of ARM with fluorescence imaging (2) the distribution of these ARM nodes and (3) whether it's safe to spare the ARM nodes in breast cancer patients during SLNB or ALND.

Method: Forty female patients of primary invasive breast cancer between 28 to 69 years old were included in the prospective study. Patients who had bilateral breast cancer, the history of axillary surgery, or the history of neoadjuvant chemotherapy were excluded. Methylene blue dye was used in the SLNB procedure. The ARM procedure was carried out to all the patients with a subcutaneous injection of the fluorescent dye indocyanine green into the medial bicipital sulcus in the upper arm about 15 minutes before SLNB or ALND. During surgery, photodynamic eye was used to detect the fluorescent nodes in the axilla. The fluorescent ARM nodes in the surgical region were removed and sent for pathological examination of node metastasis.

Results: ARM was successful in 8 out of the 35 patients who underwent SLNB + ARM, in 3 out of the 5 patients who underwent ALND + ARM and in 25 out of the 35 patients who underwent ALND following SLNB + ARM. The ARM identification rate was 22.9%(8/35) in SLNB, and was 93.3%(28/30) in ALND. Totally, 119 fluorescent ARM nodes were detected, and 57.1 % (68/119) of them were located under the axillary vein, above the 2nd intercostobrachial nerve, and in the lateral of thoracic dorsal neurovascular bundle. Six out of 35 patients were found to have ARM-SLN crossover during SLNB+ARM procedure. Two out of 24 patients were found to have the ARM nodal metastases, with the pathological node stage being pN2, pN3 respectively.

Conclusion: ARM with fluorescence imaging using indocyanine green was sensitive for identification of ARM nodes in ALND with a high success rate; ARM nodes had a certain distribution pattern in the axilla; ARM should not be performed to the patients with multiple nodal metastases in the axilla.

Citation Format: Liu J, Li J, Zhou J, Cui H, Xiang J, Jia P, Xiang A, Chen H. Axillary reverse mapping using fluorescence imaging in the surgical treatment for breast cancer patients [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-01-39.

Sex- and age-dependent expression of Pax7, Myf 5, MyoG, and Myostatin in yak skeletal muscles

The aim of this study was to investigate the myogenic factor mRNA expression pattern of Pax7, Myf5, MyoG, and Myostatin mRNA at different ages, sexes, and muscle tissues of Datong yaks. The expression patterns in semimembranosus (SM), quadriceps femoris (QF), and triceps muscle of arm (TM) were detected by quantitative real-time polymerase chain reaction and compared using biostatistics. The results showed that the Pax7 gene expression levels were higher in the hindquarters (SM and QF) than in the forequarters, and was higher in male compared to in female muscle (P ≤ 0.05). The Myf5 gene expression levels of male yaks were highest in QF (P ≤ 0.05), whereas the expression levels of female yaks were highest in TM (P ≤ 0.05). Female MyoG gene expression levels were higher in QF and TM compared to in male yaks. The MyoG expression was higher in all muscles at 6 months old compared to in 3-year-old muscle. The highest MSTN gene expression was found in 6-month-old TM muscle and in QF muscle of 3 years (P ≥ 0.05). In conclusion, yak muscles showed different growth patterns depending on position. At 6 months of age, the satellite cells in the male hindquarter muscles and the female forequarter muscle showed a strong proliferative ability, at the same time the satellite cells in all female muscles had a powerful differentiation ability. Hindquarter muscles appear to mainly grow at younger ages and forequarters mainly grow at older ages.

Over-expression of miR-125a-5p inhibits proliferation in C2C12 myoblasts by targeting E2F3

MicroRNAs (miRNAs) are a class of small non-coding RNAs of 20-25 nucleotides in length. It has been shown that miRNAs play important roles in the proliferation of many types of cells, including myoblasts. In this study, we used real-time quantitative polymerase chain reaction, western blotting, EdU, flow cytometry, and CCK-8 assay to explore the role of miR-125a-5p during the proliferation of C2C12 myoblasts. It was found that the expression of miR-125a-5p was decreased during C2C12 myoblast proliferation. Over-expression of miR-125a-5p inhibited C2C12 myoblast proliferation as indicated by EdU staining, flow cytometry, and CCK8 assay. It was also found that miR-125a-5p could negatively regulate E2F3 expression at posttranscriptional level, via a specific target site in the 3' untranslated region. Knockdown of E2F3 showed a similar inhibitory effect on C2C12 myoblast proliferation. Thus, our findings suggest that miR-125a-5p may act as a negative regulator of C2C12 myoblast proliferation by targeting E2F3.

Lysine-specific demethylase 1: an epigenetic regulator of salt-sensitive hypertension

BACKGROUND

Hypertension (HTN) represents a complex heritable disease in which environmental factors may directly affect gene function via epigenetic mechanisms. The aim of this study was to test the hypothesis that dietary salt influences the activity of a histone-modifying enzyme, lysine-specific demethylase 1 (LSD-1), which in turn is associated with salt-sensitivity of blood pressure (BP).

METHODS

Animal and human studies were performed. Salt-sensitivity of LSD-1 expression was assessed in wild-type (WT) and LSD-1 heterozygote knockout (LSD-1(+/-)) mice. Clinical relevance was tested by multivariate associations between single-nuclear polymorphisms (SNPs) in the LSD-1 gene and salt-sensitivity of BP, with control of dietary sodium, in a primary African-American hypertensive cohort and two replication hypertensive cohorts (Caucasian and Mexican-American).

RESULTS

LSD-1 expression was modified by dietary salt in WT mice with lower levels associated with liberal salt intake. LSD-1(+/-) mice expressed lower LSD-1 protein levels than WT mice in kidney tissue. Similar to LSD-1(+/-) mice, African-American minor allele carriers of two LSD-1 SNPs displayed greater change in systolic BP (SBP) in response to change from low to liberal salt diet (rs671357, P = 0.01; rs587168, P = 0.005). This association was replicated in the Hispanic (rs587168, P = 0.04) but not the Caucasian cohort. Exploratory analyses demonstrated decreased serum aldosterone concentrations in African-American minor allele carriers similar to findings in the LSD-1(+/-) mice, decreased α-EnaC expression in LSD-1(+/-) mice, and impaired renovascular responsiveness to salt loading in minor allele carriers.

CONCLUSION

The results of this translational research study support a role for LSD-1 in the pathogenesis of salt-sensitive HTN.

Independent predictors of Cesarean delivery in women with diabetes

OBJECTIVES

To identify independent risk factors for Cesarean delivery in women with pregnancy complicated by diabetes.

METHODS

Retrospective analysis of pregnancies from 5735 diabetic women delivering liveborn infants. Maternal demographic, medical, obstetric historical factors and index pregnancy obstetric, glycemic and neonatal outcome parameters were evaluated for association with Cesarean delivery after a trial of labor. Individual risk factors were analyzed for association by chi2 and ANOVA. Independent predictors of Cesarean delivery and adjusted relative risk (RR) were identified by stepwise logistic regression.

RESULTS

Trial of labor was permitted in 90.8% and 59.4% of women without (n = 4643) and with prior Cesarean delivery (n = 1092) and was successful in 85.2% and 56.9%, respectively. Eleven independent predictors were found. Five were related to obstetric history and maternal age: prior Cesarean delivery (RR 5.34, 95% CI 3.94-7.25), no prior live birth (RR 3.17, 95% CI 1.98-5.07), no prior vaginal delivery (RR 2.28, 95% CI 1.50-3.44), prior stillbirth (RR 1.71, 95% CI 1.09-2.68%) and maternal age > or = 35 years (RR 1.53, 95% CI 1.20-1.93). Two were related to the severity of diabetes at entry to diabetes care: requiring insulin (RR 1.53, 95% CI 1.20-1.93) and highest fasting plasma glucose level (RR 1.04, 95% CI 1.01-1.07). Two were related to obstetric factors: pre-eclampsia/hypertension (RR 2.56, 95% CI 2.00-3.27) and labor induction (RR 3.32, 95% CI 2.70-4.10). The remaining two were birth weight (per 250 g, RR 1.12, 95% CI 1.09-1.17) and pre-delivery body mass index (RR, 1.03, 95% CI 1.00-1.05).

CONCLUSION

The majority of predictors were not modifiable, relating to obstetric history, maternal age and diabetes severity. Possible modifiable interventions to avoid/improve labor induction, and decrease birth weight and maternal weight gain might decrease risk of Cesarean delivery. Future studies must address these multiple predictors.

Discovery of the first non-peptide antagonist of the motilin receptor

A first-in-class non-peptide antagonist of the motilin receptor was identified through electronic screening of our corporate database against a 3D pharmacophore. The pharmacophore was developed from the motilin 22 residue endogenous peptide using NMR structural data, principles of peptide folding, and peptide structure activity relationships. The NMR data supported helical content within the peptide, and both the hydrophobic staple and N-capping box motifs were identified in the motilin sequence. The conformational features of these motifs were imposed on the peptide structure, providing a constrained conformer as a starting point for database searching. A trisubstituted cyclopentene lead was identified directly from the electronic search. Compounds in this series inhibit the binding of 125I-motilin to human antral smooth muscle membrane and antagonize motilin-induced intracellular calcium mobilization in cells expressing the human motilin receptor. A potent compound developed through optimization, RWJ 68023, is active in binding and cell-based functional assays and is also effective in inhibiting motilin-induced contractility in segments of rabbit duodenum. This orally active compound is currently undergoing clinical evaluation for the treatment of gastrointestinal disorders associated with altered motility.

Patterns of congenital anomalies and relationship to initial maternal fasting glucose levels in pregnancies complicated by type 2 and gestational diabetes

OBJECTIVES

We sought to determine the types of congenital anomalies affecting infants of women with gestational diabetes mellitus or type 2 diabetes and to examine the relationship between those malformation types and measures of initial glycemia of women at entry into prenatal care with type 2 diabetes or at time of diagnosis in women with gestational diabetes mellitus.

STUDY DESIGN

A total of 4,180 pregnancies complicated by gestational diabetes mellitus (n = 3764) or type 2 diabetes (n = 416) that were delivered after 20 weeks of gestation were reviewed for the presence of congenital malformations diagnosed before hospital discharge. Anomalies were categorized as being absent, minor, major, genetic syndromes, or aneuploidies. Major anomalies were further categorized by the number and type of affected organ systems. In addition to maternal clinical and historical parameters, the initial fasting serum glucose either from the diagnostic glucose tolerance test (gestational diabetes mellitus) or at entry to prenatal care (type 2 diabetes) and the initial glycosylated hemoglobin before insulin therapy were examined for a relationship to anomalies.

RESULTS

The initial fasting serum glucose and glycosylated hemoglobin levels were significantly higher in pregnancies with major (n = 143) and minor (n = 112) anomalies and genetic syndromes (n = 9) compared with pregnancies with no anomalies (n = 3895). Of those pregnancies with major anomalies, the most commonly affected organ systems were the cardiac (37.6%), musculoskeletal (14.7%), and central nervous systems (9.8%) and anomalies involving multiple organ systems (16%). There was no increased predominance of any specific organ system involvement seen with increasing fasting serum glucose levels in pregnancies with major congenital anomalies. Pregnancies with major anomalies affecting multiple organ systems had significantly higher initial fasting serum glucose levels (166 +/- 64 mg/dL) compared with pregnancies in which one organ system was affected (141 +/- 55 mg/dL, P <.04) or no organ systems were affected (115 +/- 38 mg/dL, P <.0001).

CONCLUSION

Congenital anomalies in offspring of women with gestational and type 2 diabetes affect the same organ systems that have been previously described in pregnancies complicated by type 1 diabetes. Increasing hyperglycemia at diagnosis or presentation for care was associated with an increasing risk of anomalies in general and with anomalies involving multiple organ systems without a preferential increase in involvement of specific organ system.

Latency analysis in epidemiologic studies of occupational exposures: application to the Colorado Plateau uranium miners cohort

BACKGROUND

Latency effects are an important factor in assessing the public health implications of an occupational or environmental exposure. Usually, however, latency results as described in the literature are insufficient to answer public health related questions. Alternative approaches to the analysis of latency effects are warranted.

METHODS

A general statistical framework for modeling latency effects is described. We then propose bilinear and exponential decay latency models for analyzing latency effects as they have parameters that address questions of public health interest. Methods are described for fitting these models to cohort or case-control data; statistical inference is based on standard likelihood methods.

APPLICATION

A latency analysis of radon exposure and lung cancer in the Colorado Plateau uranium miners cohort was performed. We first analyzed the entire cohort and found that the relative risk associated with exposure increases for about 8.5 years and thereafter decreases until it reaches background levels after about 34 years. The hypothesis that the relative risk remains at its peak level is strongly rejected (P < 0.001). Next, we investigated the variation in the latency effects over subsets of the cohort based on attained age, level and rate of exposure, and smoking. Age was the only factor for which effect modification was demonstrated (P = 0.014). We found that the decline in effect is much steeper at older ages (60+ years) than younger.

CONCLUSION

The proposed methods can provide much more information about the exposure-disease latency effects than those generally used.

Effects of airway inflammation on cough response in the guinea pig

We have developed a guinea pig model for cough related to allergic airway inflammation. Unanesthetized animals were exposed to capsaicin aerosols for 10 min, and cough frequency was counted during this period. The cough evaluation was performed by the following three methods: visual observation, acoustic analysis, and monitoring of pressure changes in the body chamber. These analyses clearly differentiated a cough from a sneeze. To elucidate the relationship between cough response and airway inflammation, animals were immunosensitized and multiple challenged. Sensitized guinea pigs presented no specific changes microscopically, but multiple-challenged animals showed an increased infiltration of inflammatory cells into the airway. Cough number in response to capsaicin increased significantly from 4.7 +/- 1.4 coughs/10 min in normal animals to 10.6 +/- 2.0 coughs/10 min in sensitized animals and further to 22.8 +/- 1.3 coughs/10 min in multiple-challenged animals. This augmented cough frequency was significantly inhibited by the inhalation of tachykinin-receptor antagonists and by oral ingestion, but not inhalation, of codeine phosphate. The results suggest that airway inflammation potentiates an elevation of cough sensitivity in this model.

Contraception and the risk of type 2 diabetes mellitus in Latina women with prior gestational diabetes mellitus

CONTEXT

Effective contraception is essential in women with prior gestational diabetes mellitus (GDM) but should not increase their already substantial risk of developing type 2 diabetes.

OBJECTIVE

To determine whether exposure to low-dose oral contraceptives increases the risk of developing type 2 diabetes mellitus in women with recent GDM.

DESIGN

Retrospective cohort study of 904 Latinas with GDM who gave birth between January 1987 and March 1994, in whom postpartum diabetes was excluded at 4 to 16 weeks post partum.

INTERVENTIONS

At their initial postpartum visit, 443 women selected a nonhormonal form of contraception, 383 received a low-dose, estrogen-progestin combination oral contraceptive (OC), and 78 breast-feeding women received the progestin-only OC. When breast-feeding ended, patients initially taking progestin-only OCs were switched to combination OCs. Patients were followed up periodically with oral glucose tolerance tests for up to 7 1/2 years.

MAIN OUTCOME MEASURES

Person time was used to compute unadjusted average annual incidence rates of developing diabetes mellitus, as defined by the National Diabetes Data Group Criteria. Survival analysis was used to compute the unadjusted cumulative incidence rates and adjusted relative risks of diabetes mellitus.

RESULTS

The unadjusted average annual incidence rates of type 2 diabetes mellitus were 8.7%, 10.4%, and 26.5%, respectively, for patients using nonhormonal forms of contraception, combination OCs, and progestin-only OCs. Cumulative incidence rates were virtually identical for patients with uninterrupted use of combination OCs and nonhormonal forms of contraception, but patients using progestin-only OCs developed diabetes mellitus more rapidly during the first 2 years of use. After adjustment for potential confounding factors, the use of progestin-only OCs almost tripled the risk of type 2 diabetes mellitus compared with equivalent use of low-dose combination OCs (adjusted relative risk, 2.87; 95% confidence interval, 1.57-5.27). The magnitude of this risk increased with duration of uninterrupted use.

CONCLUSION

Progestin-only OCs were associated with an increased risk of diabetes in breast-feeding Latinas with recent GDM and probably should be prescribed with caution, if at all, in these women. Long-term use of low-dose combination OCs did not increase the risk of type 2 diabetes compared with use of nonhormonal contraception. Thus, combination OCs do not appear to increase the risk of diabetes in non-breast-feeding women with recent GDM.

Gestational diabetes: antepartum characteristics that predict postpartum glucose intolerance and type 2 diabetes in Latino women

We examined antepartum clinical characteristics along with measures of glucose tolerance, insulin sensitivity, pancreatic beta-cell function, and body composition in Latino women with gestational diabetes mellitus (GDM) for their ability to predict type 2 diabetes or impaired glucose tolerance (IGT) within 6 months after delivery. A total of 122 islet cell antibody-negative women underwent oral and intravenous glucose tolerance tests (OGTT; IVGTT), hyperinsulinemic-euglycemic clamps, and measurement of body fat between 29 and 36 weeks' gestation and returned between 1 and 6 months postpartum for a 75-g OGTT. Logistic regression analysis was used to examine the relationship between antepartum variables and glucose tolerance status postpartum. At postpartum testing, 40% of the cohort had normal glucose tolerance, 50% had IGT, and 10% had diabetes by American Diabetes Association criteria. Independent antepartum predictors of postpartum diabetes were the 30-min incremental insulin:glucose ratio during a 75-g OGTT (P = 0.0002) and the total area under the diagnostic 100-g glucose tolerance curve (P = 0.003). Independent predictors of postpartum IGT were a low first-phase IVGTT insulin response (P = 0.0001), a diagnosis of GDM before 22 weeks' gestation (P = 0.003), and weight gain between prepregnancy and the postpartum examination (P = 0.03). All subjects had low insulin sensitivity during late pregnancy, but neither glucose clamp nor minimal model measures of insulin sensitivity in the 3rd trimester were associated with the risk of IGT or diabetes within 6 months' postpartum. These results highlight the importance of pancreatic beta-cell dysfunction, detectable under conditions of marked insulin resistance in late pregnancy, to predict abnormalities of glucose tolerance soon after delivery in pregnancies complicated by GDM. Moreover, the association of postpartum IGT with weight gain and an early gestational age at diagnosis of GDM suggests a role for chronic insulin resistance in mediating hyperglycemia outside the 3rd trimester in women with such a beta-cell defect.

Hormonal choices after gestational diabetes. Subsequent pregnancy, contraception, and hormone replacement

The effects of subsequent states of excess hormone exposure, for example, subsequent pregnancy, hormonal contraception, and hormonal replacement therapy, on the development of diabetes in women with prior gestational diabetes were assessed. Current literature examining the effect of parity, hormonal contraception, and hormonal replacement therapy in healthy women and women with previous gestational diabetes and current diabetes was reviewed. Subsequent pregnancy in women with prior GDM appears to triple the risk of subsequent diabetes. Low-dose progestin and estrogen combination oral contraceptives do not appear to clinically increase the risk of diabetes. Hormonal replacement therapy appears to provide the greatest reduction in coronary artery disease to women at greatest risk, i.e., those who have developed diabetes. Careful follow-up and metabolic surveillance should be provided when prescribing hormonal contraception or replacement therapy. In women with prior gestational diabetes, exposure to repeat pregnancy poses a greater risk for subsequent diabetes than does either an exposure to low-dose progestin and estrogen combination oral contraceptives or to postmenopausal hormonal therapy, both of which do not appear to increase the risk of diabetes.

Utility of fetal measurements in the management of gestational diabetes mellitus

The metabolic management of gestational diabetes mellitus (GDM) during pregnancy traditionally has focused on maintenance of circulating maternal glucose concentrations in all patients within a range that is associated with a low rate of perinatal morbidity, especially morbidity related to excessive fetal growth and macrosomia. Clinical data reviewed elsewhere in this supplement provide guidelines for glycemic targets that appear to eliminate the excess risk to the fetus. However, because only a minority of infants are at risk for perinatal morbidity over the range of glycemia generally encountered in patients with GDM, attainment of those strict glycemic targets in all women with GDM requires implementation of self-monitoring of glucose and exogenous insulin therapy in many pregnancies that are not at risk. In this article, we review management approaches that take into account not only maternal glycemia, but also fetal growth and metabolic parameters in selecting GDM pregnancies for intensive metabolic therapy. The approaches can reduce the number of women with mild GDM who require self-monitoring of glucose and/or exogenous insulin therapy, thereby providing the potential to improve cost-effectiveness of antepartum management of GDM.

Role of endogenous nitric oxide in allergen-induced airway responses in guinea-pigs

1. Endogenous nitric oxide (NO) can be detected in exhaled air and accumulates in inflamed airways. However its physiological role has not been fully elucidated. In this study, we investigated a role for endogenous NO in allergen-induced airway responses. Sensitised guinea-pigs were treated with NG-nitro-L-arginine methyl ester L-NAME (2.0 mM) or aminoguanidine (AG) (2.0 mM) 30 min before the allergen challenge, and 3 and 4 h after the challenge. Alternatively, L-arginine (2.4 mM) treatment was performed 30 min before, and 2 and 3 h after the challenge. In all groups, ovalbumin (OVA) challenge (2 mg ml(-1) for 2 min) was performed, and airway responses, NO production, infiltration of inflammatory cells, plasma exudation and histological details were examined. 2. Allergen-challenged animals showed an immediate airway response (IAR) and a late airway response (LAR), which synchronised with an increase in exhaled NO. Treatment with L-NAME and AG did not affect IAR while they significantly blocked LAR (72% and 80% inhibition compared to vehicle) and production of NO (35% and 40% inhibition). On the other hand, treatment with L-arginine did not affect IAR but potentiated LAR (74% augmentation). 3. In bronchoalveolar lavage (BAL) fluid, allergen-induced increases in eosinophils were reduced by 48% for L-NAME treatment compared to vehicle, and increased by 56% for L-arginine treatment. 4. Treatment with L-NAME significantly decreased airway microvascular permeability to both Monastral blue (MB) and Evans blue (EB) dye (50.6% and 44% inhibition). 5. We conclude that allergen-induced LAR is closely associated with NO production, and that NO plays a critical role in inflammatory cell infiltration and plasma exudation in the allergic condition.

TRIPOD (TRoglitazone In the Prevention Of Diabetes): a randomized, placebo-controlled trial of troglitazone in women with prior gestational diabetes mellitus

The TRoglitazone In the Prevention Of Diabetes (TRIPOD) trial is a single-center, randomized, placebo-controlled, double-masked study. The primary aim of the TRIPOD trial is to test the hypothesis that chronic administration of troglitazone to nondiabetic women with prior gestational diabetes mellitus (GDM) will improve whole-body insulin sensitivity and reduce the incidence of non-insulin-dependent diabetes (NIDDM). Because troglitazone is already known to lower blood glucose concentrations in persons who have developed NIDDM, an additional aim of the project will be to determine whether early intervention with troglitazone will achieve better final glycemic control than can be achieved by later intervention. In addition, since troglitazone treatment is expected to improve insulin sensitivity and may prevent or delay a decline in glucose tolerance, we also plan to determine whether long-term troglitazone treatment alters the development or progression of atherosclerosis. In this article we describe the experiment's design, the study's endpoints and methods for determining those endpoints, methods for assessing quality of life, and proposed methods for statistical analyses. The unique two-phase study design of the TRIPOD trial will permit testing not only of the biological question about reversal of insulin resistance and prevention of diabetes, but also of the clinical question about whether early intervention is superior to late intervention. Results from this trial will have an important impact on the monitoring and treatment of patients at high risk for NIDDM.

Congenital malformations in offspring of women with hyperglycemia first detected during pregnancy

OBJECTIVES

Our aim was to determine risk factors for congenital malformations in offspring of women with hyperglycemia first detected during pregnancy (i.e., women with gestational diabetes).

STUDY DESIGN

A total of 3743 pregnancies complicated by gestational diabetes mellitus delivered at > 20 weeks of gestation were reviewed for the presence of congenital malformations diagnosed before hospital discharge. Anomalies were categorized as major, minor, or absent. Pregnancies with genetic syndromes and aneuploidies were excluded. In addition to maternal clinical and historic parameters, diagnostic glycemic parameters (fasting and post-glucose-challenge levels from the diagnostic glucose tolerance test, highest fasting serum glucose level, and hemoglobin A1c level before insulin therapy) were examined by logistic regression for predictive risk of major anomalies.

RESULTS

One or more major congenital anomalies were present in 108 (2.9%) of the newborns; an additional 91 (2.4%) had only minor anomalies. None of the maternal variables were associated with the risk of minor anomalies. By contrast, parity, a history of gestational diabetes mellitus, and several glycemic parameters were associated with the risk of major anomalies. The highest fasting serum glucose level was the best independent predictor (odds ratio 1.13/10 mg/dl, 95% confidence interval 1.09 to 1.34). The fasting serum glucose level at diagnosis, a parameter that is almost uniformly available to clinicians, gave similar predictive information about the risk of major anomalies (odds ratio 1.13, 95% confidence interval 1.08 to 1.14). Stratification of women into subgroups of fasting serum glucose level at diagnosis revealed the incidence of major anomalies to be as follows: 2.1% with a fasting serum glucose level < 120 mg/dl (2973 pregnancies), 5.2% with a fasting serum glucose level of 121 to 260 mg/dl (747 pregnancies), and 30.4% with a fasting serum glucose level > 260 mg/dl (23 pregnancies).

CONCLUSION

In a large population of women without a diagnosis of diabetes before pregnancy, the maternal fasting serum glucose concentration at diagnosis was a useful predictor of the risk of major but not minor anomalies. The rate of major anomalies doubled with a fasting glucose level > 120 mg/dl. Thus a fasting glucose level below that of overt diabetes outside of pregnancy carries an important risk of major anomalies that must be considered in the counseling and management of these patients.

Effect of troglitazone on insulin sensitivity and pancreatic beta-cell function in women at high risk for NIDDM

We conducted a randomized placebo-controlled study to determine the effects of the thiazolidinedione compound troglitazone on whole-body insulin sensitivity (SI), pancreatic beta-cell function, and glucose tolerance in 42 Latino women with impaired glucose tolerance (IGT) and a history of gestational diabetes mellitus (GDM), characteristics that carry an 80% risk of developing NIDDM within 5 years. After baseline oral (OGTT) and intravenous (IVGTT) glucose tolerance testing, subjects were assigned to take placebo or 200 or 400 mg troglitazone daily for 12 weeks (14 subjects per treatment group). An OGTT and IVGTT were repeated during the 12th week of treatment. Five subjects failed to complete the trial for personal reasons, and medication compliance averaged 90% in the remaining subjects, none of whom experienced a serious adverse event. SI, calculated by minimal model analysis of IVGTT results, changed by only 4 +/- 14% during 12 weeks of placebo administration, but increased 40 +/- 22 and 88 +/- 22% above basal during treatment with 200 and 400 mg troglitazone, respectively (P = 0.01 among groups). Troglitazone administration was also associated with a dose-dependent reduction in the total insulin area during IVGTTs, which was highly significant (P < 0.001), and with a reduction during OGTTs, which approached statistical significance (P = 0.09). Glucose tolerance improved slightly in all groups, but the magnitude of change did not differ significantly among groups, whether it was assessed as the number of subjects who continued to manifest IGT at 12 weeks (P = 0.64 among groups), the change in total glucose area during OGTTs (P = 0.58), or the change in fractional glucose disappearance rates during IVGTTs (P = 0.28). Among the women who received troglitazone, the greatest improvement in SI occurred in the women who had the highest diastolic blood pressures and the best IVGTT insulin responses during baseline testing. Our findings indicate that troglitazone improved whole-body insulin sensitivity and lowered circulating insulin concentrations in women with prior GDM who are at very high risk for NIDDM. The lack of improvement in glucose tolerance despite improved insulin sensitivity may be a manifestation of the beta-cell defect that predisposes the women to NIDDM. The overall pattern of response to troglitazone in our high-risk patients indicates that the drug is an ideal agent with which to test whether the amelioration of insulin resistance can delay or prevent diabetes in women with limited beta-cell reserve.

Regional expression of sodium pump subunits isoforms and Na+-Ca++ exchanger in the human heart

Cardiac glycosides exert a positive inotropic effect by inhibiting sodium pump (Na,K-ATPase) activity, decreasing the driving force for Na+-Ca++ exchange, and increasing cellular content and release of Ca++ during depolarization. Since the inotropic response will be a function of the level of expression of sodium pumps, which are alpha(beta) heterodimers, and of Na+-Ca++ exchangers, this study aimed to determine the regional pattern of expression of these transporters in the heart. Immunoblot assays of homogenate from atria, ventricles, and septa of 14 nonfailing human hearts established expression of Na,K-ATPase alpha1, alpha2, alpha3, beta1, and Na+-Ca++ exchangers in all regions. Na,K-ATPase beta2 expression is negligible, indicating that the human cardiac glycoside receptors are alpha1beta1, alpha2beta1, and alpha3beta1. alpha3, beta1, sodium pump activity, and Na+-Ca++ exchanger levels were 30-50% lower in atria compared to ventricles and/or septum; differences between ventricles and septum were insignificant. Functionally, the EC50 of the sodium channel activator BDF 9148 to increase force of contraction was lower in atria than ventricle muscle strips (0.36 vs. 1.54 microM). These results define the distribution of the cardiac glycoside receptor isoforms in the human heart and they demonstrate that atria have fewer sodium pumps, fewer Na+-Ca++ exchangers, and enhanced sensitivity to inotropic stimulation compared to ventricles.

Long-term diabetogenic effect of single pregnancy in women with previous gestational diabetes mellitus

BACKGROUND

Pregnancy is associated with marked insulin resistance that seems to have little, if any, impact on the long-term risk of non-insulin-dependent diabetes mellitus (NIDDM) in the general population. The aim of this study was to test whether pregnancy would alter the risk of NIDDM among women with a high prevalence of pancreatic beta-cell dysfunction, as indicated by a history of gestational diabetes mellitus.

METHODS

The cohort consisted of 666 Latino women with gestational diabetes attending a high-risk family planning clinic. They were followed up for up to 7.5 years, during which time they were weighed and underwent an oral glucose-tolerance test annually. The effect of an additional pregnancy, and of other risk factors for diabetes, was examined.

FINDINGS

87 (13%) of the women completed an additional pregnancy. 80 of those women did not have NIDDM immediately after the additional pregnancy and their subsequent annual incidence rate of NIDDM was 30.9% (95% CI 12.7-49.1), more than 2.5 times the annual incidence rate of NIDDM in the cohort overall (11.9%; 95% CI 10.0-13.8). Proportional hazards regression analysis using the presence or absence of an additional pregnancy as a time-dependent variable confirmed that an additional pregnancy increased the rate ratio of NIDDM to 3.34 (95% CI 1.80-6.19), compared with women without an additional pregnancy after adjustment for other potential diabetes risk factors during the index pregnancy (antepartum oral glucose tolerance, highest fasting glucose, gestational age at diagnosis of gestational diabetes) and during follow-up (postpartum body mass index [BMI], and glucose tolerance, weight change, breast feeding, and months of contraceptive use). Weight gain also was independently associated with an increased risk of NIDDM; the rate ratio was 1.95 (95% CI 1.63-2.33) for each 10 lb (4.5 kg) gained during follow-up after adjustment for the additional pregnancy and the other potential risk factors.

INTERPRETATION

The study showed that a single pregnancy, independent of the well-known effect of weight gain, accelerated the development of NIDDM in a group of women with a high prevalence of pancreatic beta-cell dysfunction. This finding implies that episodes of insulin resistance may contribute to the decline in beta-cell function that leads to NIDDM in many high-risk individuals.

[Increased production of nitric oxide in the immediate and late asthmatic responses in models of guinea pig experimental asthma]

Nitric oxide is produced in mammalian airways by constitutive and inducible nitric oxide synthase, and endogenous nitric oxide can be detected as exhaled gas. Patients with asthma have large numbers of airway epithelial cells and inflammatory cells that contain nitric oxide synthase, and nitric oxide levels in exhaled air are high during immediate asthmatic responses. To examine the dynamics of nitric oxide synthase in the tracheas of guinea pigs, cumulative dose-response studies of 5-HT were done on tracheal strips, in the presence or absence of arginine and its analogues. This assay indicated that relative the activity of nitric oxide synthase was greater 6 hr after the challenge than immediately after, which suggests that nitric oxide is involved in the pathogenesis of bronchial asthma attacks.

Congenital malformations in pregnancies complicated by NIDDM

OBJECTIVE

To determine whether the use of oral hypoglycemic agents during early pregnancy is associated with a risk of congenital malformations in infants of mothers with non-insulin-dependent diabetes mellitus (NIDDM) independent of maternal metabolic control.

RESEARCH DESIGN AND METHODS

From a prospectively collected data-base of pregnancies complicated by diabetes at a large urban medical center, we identified 332 consecutive infants born to women with NIDDM who did not participate in a preconceptional diabetes care program. Stepwise logistical regression was used to identify maternal characteristics that were independently associated with risks of major and minor congenital malformations in infants.

RESULTS

Overall, 56 (16.9%) of the 332 infants were born with congenital anomalies (11.7% major anomalies and 5.1% minor anomalies). Analysis of data from subgroups of women who were treated with diet therapy, exogenous insulin, or sulfonylurea compounds during the first 8 weeks of gestation did not reveal statistically significant differences in major or minor malformation rates among the three groups. Stepwise logistic regression analysis revealed two maternal characteristics that were independently associated with major malformations in infants: maternal HbA1c at initial presentation for care (direct relationship; P = 0.0007) and the maternal age at onset of diabetes (inverse relationship; P = 0.009). The risk of major malformations was unrelated to the mode of antidiabetic therapy during early pregnancy. No relationship was found between maternal glycemia or treatment modality and rates of minor congenital anomalies.

CONCLUSIONS

These data indicate that, in the absence of special preconceptional care, NIDDM is associated with a risk for major congenital anomalies that is in the range reported for pregnancies complicated by insulin-dependent diabetes mellitus. Moreover, the risk in individual patients appears to be related to maternal glycemic control rather than to the mode of antidiabetic therapy during early pregnancy.

Predicting future diabetes in Latino women with gestational diabetes. Utility of early postpartum glucose tolerance testing

We tested 32 routine clinical parameters for their ability to discriminate between a high risk and a low risk of non-insulin-dependent diabetes mellitus (NIDDM) within 5-7 years after pregnancies complicated by gestational diabetes mellitus (GDM). Latino women (n = 671) with GDM who did not have diabetes 4-16 weeks after delivery returned for at least one 75-g oral glucose tolerance test (OGTT) within 7.5 years. Multivariate analysis was used to identify parameters ascertained during or immediately after the index pregnancy that were independently associated with the development of diabetes during follow-up. Life table analysis revealed a 47% cumulative incidence rate of NIDDM 5 years after delivery for this cohort of patients who did not have diabetes at the initial postpartum examination. Four variables were identified as independent predictors of NIDDM: the area under the OGTT glucose curve at 4-16 weeks postpartum, the gestational age at the time of diagnosis of GDM, the area under the OGTT glucose curve during pregnancy, and the highest fasting serum glucose concentration during pregnancy. Examination of relative risks (RRs) of NIDDM between the highest and lowest quartiles of the cohort for each variable, adjusted for the other three variables, revealed that the postpartum OGTT provided the best discrimination between high-risk and low-risk individuals (adjusted RR = 11.5 [95% confidence interval 4.5-29.1] compared with adjusted RRs of only 0.5-2.5 for the other three variables).(ABSTRACT TRUNCATED AT 250 WORDS)

The copper T380A intrauterine device in women with type II diabetes mellitus

OBJECTIVE

To evaluate the safety and efficacy of the copper T380A intrauterine device (IUD) in women with type II, non-insulin-dependent diabetes mellitus.

METHODS

From June 1988, 176 women with type II diabetes, in whom the copper T380A IUD was inserted, were followed prospectively until: study closure (June 1993); termination for pregnancy, expulsion, or removal for medical or personal reasons; or termination for loss to follow-up.

RESULTS

Sixteen women never returned after initial insertion, leaving 160 women who were followed a total of 3066 months, with 117 continuing follow-up after their reexamination visit 6-12 weeks after insertion. None developed acute salpingitis. The overall removal rates per 100 woman-years were as follows: for pregnancy, 1.57; for expulsion, 1.96; for discontinuation because of medical reasons (including pain and bleeding), 4.31; and for personal reasons, 3.91. The continuation rate at the end of 3 years after insertion was 70%.

CONCLUSION

The copper T380A IUD appears to be safe and effective in women with type II diabetes when standard criteria for IUD insertion are followed.

Use of fetal ultrasound to select metabolic therapy for pregnancies complicated by mild gestational diabetes

OBJECTIVE

To determine whether fetal ultrasound early in the third trimester can identify Latina with mild gestational diabetes mellitus (GDM) whose fetuses are at risk for macrosomia and, if so, whether maternal insulin therapy can reduce that risk.

RESEARCH DESIGN AND METHODS

Study subjects included 303 consecutive women with GDM and a fasting serum glucose level < 5.8 mM on diet therapy who had a fetal ultrasound between 29 and 33 weeks gestation. Of the women, 98 (32%) had a fetal AC > or = 75th percentile for gestational age, and 59 women completed a randomized trial of diet therapy (n = 29) or diet plus twice daily insulin (n = 30). Maternal nutrient levels were assessed by meal tolerance testing (MTT) before and during therapy and by capillary glucose monitoring four to seven times a day. Birth weights corrected for gestational age and neonatal glycemia and skin folds were the primary outcome variables compared between treatment groups.

RESULTS

Diet and diet-plus-insulin groups were well matched for maternal age, prepregnancy relative weight, weight gain during pregnancy, and glycemia at entry. Insulin therapy reduced maternal capillary (P < 0.005) and MTT (P < 0.001) glucose levels and prevented a diet-associated rise in MTT triglyceride levels (P < 0.002). Gestational age at delivery was similar in insulin- and diet-treated groups (39.6 +/- 0.2 vs. 39.5 +/- 0.2 weeks). Birth weights (3,647 +/- 67 vs. 3,878 +/- 84 g; P < 0.02), the prevalence of large-for-gestational age infants (13 vs. 45%, P < 0.02), and neonatal skin-fold measurements at three sites (P < 0.005) were reduced in the insulin-treated group. Rates of transient neonatal hypoglycemia were low in both treatment groups (14 and 18%, respectively) and did not differ significantly between groups.

CONCLUSIONS

Fetal ultrasound early in the third trimester identified women with mild GDM whose infants were at high risk for fetal macrosomia in the absence of standard glycemic criteria for insulin therapy. Insulin treatment reduced the macrosomia, indicating that fetal ultrasound can be used to guide metabolic therapy in pregnancies complicated by mild GDM.

Angiotensin II increases glucose utilization during acute hyperinsulinemia via a hemodynamic mechanism

To determine whether hemodynamic changes can modulate insulin action in vivo, we administered angiotensin II (AII) to normal men under three separate, euglycemic conditions. First, in the presence of physiological hyperinsulinemia (approximately 115 microU/ml), infusion of AII at rates of 2, 10, and 20 ng/min per kg caused significant elevations of blood pressure, whole-body glucose clearance, and plasma insulin concentrations in an AII dose-dependent manner. Second, in the presence of plasma insulin concentrations that stimulate glucose transport maximally (approximately 5,000 microU/ml), AII infusions increased whole-body glucose clearance without enhancing glucose extraction across the leg. Third, in the presence of basal insulin concentrations (approximately 13 microU/ml), AII infusions had no effect on whole-body glucose turnover or leg glucose extraction. Thus, AII enhanced whole-body glucose utilization without directly stimulating glucose transport in a major skeletal muscle bed. To evaluate a possible hemodynamic mechanism for the effects of AII on glucose utilization, we measured blood flow to two areas that differ in their sensitivity to insulin: the kidneys and the leg. We found that AII redistributed blood flow away from the predominantly insulin-independent tissues of the kidney and toward the insulin-sensitive tissues of the leg during both sham and hyperinsulinemic glucose clamps. The redistribution of flow had no effect on whole-body glucose turnover when leg glucose uptake was unstimulated (sham clamps). However, when leg glucose uptake was activated by insulin, the redistribution of flow caused a net increase in whole-body glucose utilization. Our findings indicate that hemodynamic factors can modulate insulin action in vivo. Furthermore, our results suggest that variable activity of the renin-angiotensin system may contribute to inconsistencies in the association between insulin resistance and hypertension.