Association of obesity with socioeconomic status among adults of ages 18 to 80 years in rural Northwest China

Background

Understanding social disparities in obesity are presently an essential element in establishing public health priorities. However, the association between socioeconomic status (SES) and obesity has not been assessed in rural Northwest China. This study aims to explore the effect of SES on overweight/obesity and abdominal obesity by gender and age in rural Northwest China.

Methods

A total of 3030 participants between the ages of 18 to 80 years from rural Hanzhong, Shaanxi province, Northwest China were enrolled in our study using a two-level stratified random cluster sampling technique. Adjusted odds ratio (AOR) were used to assess the relationship between socioeconomic status and obesity after controlling for confounding factors using logistic regression.

Results

Our results indicated that the prevalence of abdominal obesity (38.8%) was the highest in rural Northwest China when compared with overweight (27.8%) and obesity (5.7%). When adjusting for possible risk factors, there were significant gender disparities in SES-obesity association. In men, the likelihoods of overweight/obesity and abdominal obesity were higher in the high SES groups when compared to the low SES groups. However, women with a high level of education were less likely to have overweight/obesity (AOR:0.78, 95% CI: 0.62, 0.98) than their counterparts with a low level of education. After the inclusion of multiple lifestyle factors, we still observed a strong positive association between age and obesity in the population.

Conclusions

Both gender and age differences in SES-obesity association were clearly observed in our study. Therefore, interventional measures should be employed in rural Northwest China to reduce the obesity epidemic that specifically takes into account gender and age differences.

The evaluation of maternal health in rural western China

OBJECTIVE

The double burden of undernutrition and overnutrition is recognized as a global devastating problem. However, few studies have investigated the maternal nutritional status among different ethnicities and the socio-demographic characteristics in rural areas of western China. This study attempted to fill this gap.

DESIGN

Data on 10,495 women with children under three years old were collected using a three-stage probability proportion to size sampling from 45 counties of 10 provinces in western China. Generalized Estimating Equation (GEE) was used to assess the maternal nutrition conditions, including chronic energy deficiency (CED) and overweight/obesity.

RESULTS

According to the WHO BMI standard, the prevalences of CED and overweight/obesity were 12.3% (BMI≤18.5 kg/m2) and 12.4% (BMI≥25 kg/m2), respectively, while overweight/obesity rate was 18.5% (BMI≥24 kg/m2) based on the Chinese standard. A significant difference in malnutrition between Han and Minority was not observed. The relationship between breastfeeding and CED was inverse (OR 0.64, 95%CI: 0.48, 0.87), but higher parity were positively correlated with CED (OR 1.57, 95%CI: 1.36, 1.82). The highest odds of CED were observed in the group with 1-5 years of education (OR 1.21, 95%CI: 1.03, 1.43). Higher parity was also associated with overweight/obesity (OR 0.78, 95%CI: 0.67, 0.91), and rural women aged 30-39 years old were more likely to be overweight/obese (OR 2.21, 95%CI: 1.47, 3.32). In addition, higher socioeconomic status was positively related to overweight women (OR 1.19, 95%CI: 1.01, 1.43), and inversely associated with CED (OR 0.83, 95%CI: 0.72, 0.97).

CONCLUSION

The coexistence of undernutrition and overweight among women of reproductive age are determined in rural western China. It appears that socio-demographic factors considerably influence maternal nutritional status in the study. These findings have important policy implications for recommendations on maternal health intervention in China.

A survey of undernutrition in children under three years of age in rural Western China

Background

Childhood undernutrition adversely impacts child health and is one of China’s largest health burdens. However, there is limited information on the current rate of childhood undernutrition in rural Western China. The purpose of this study was to investigate the prevalence of childhood undernutrition and explore its association with socio-economic characteristics in Western China.

Methods

A total of 13,532 children of 0 ~ 36 months of age were recruited as subjects from 45 counties and 10 provinces in Western China with a 3-stage probability proportion to size sampling. The composite index of anthropometric failure (CIAF) was used to assess the childhood undernutrition. The association between socio-economic characteristics and childhood undernutrition was analyzed using a two-level logistic regression.

Results

Based on CIAF, the prevalence of undernutrition among children under three years of age in rural Western China in 2005 was 21.7%. The two-level logistic analysis presented a large difference in undernutrition among the 10 provinces with the highest odds ratio in Guizhou (OR: 2.15, 95%CI: 1.50, 3.08). Older children had a higher prevalence of undernutrition. As compared to girls, boys were more likely to be undernourished (OR 1.27, 95% CI: 1.16, 1.39). The likelihood of undernutrition was lower in subjects of Han ethnicity as opposed to subjects of minority ethnicities (OR 0.77, 95%CI: 0.65, 0.90). In addition, the education levels of the mother as well as wealth index were both negatively associated with childhood undernutrition.

Conclusions

Childhood undernutrition still remains a large health challenge in rural Western China. This study has important policy implications for the Chinese government to improve childhood undernutrition in the surveyed areas.

Caesarean delivery, caesarean delivery on maternal request and childhood overweight: a Chinese birth cohort study of 181 380 children

What is already known about this subject Both rates of caesarean section and childhood overweight have been steadily increasing over the past decade in many parts of the world. Caesarean delivery on maternal request contributes remarkably to the rising trend of caesarean births. A few small-scale studies suggest that caesarean section may be associated with later overweight and obesity, whereas little is known about the impact of caesarean delivery on maternal request. What this study adds Caesarean section is associated with an increased risk of childhood overweight. Children born by caesarean delivery on maternal request are also more likely to be overweight. The strength of the caesarean-overweight association is modest.

OBJECTIVES

To assess the impact of caesarean delivery including non-medically indicated maternal request caesarean delivery on childhood overweight.

METHODS

We conducted a prospective investigation of a Chinese birth cohort involving 181 380 children, who were born during 1993-1996 to mothers registered in a perinatal care surveillance system and whose weight and height were measured in 2000. Information on delivery mode and covariates was obtained from the surveillance system. Overweight was defined according to the International Obesity Task Force body mass index (BMI) cutoffs. Multivariable logistic regression was used to estimate adjusted odds ratios. Stratified analyses were done to test whether the association between caesarean section and overweight persisted across subgroups.

RESULTS

The adjusted odds ratio of overweight for children born by caesarean compared with vaginal delivery was 1.13 [95% confidence interval {CI}: 1.08, 1.18]. The association persisted in subgroups stratified by gender, maternal education, maternal BMI, weight gain during pregnancy and child birthweight (all P values for interaction test ≥0.30). The adjusted odds ratio of overweight for children born by non-medically indicated caesarean delivery compared with vaginal delivery was 1.18 (95% CI: 1.00, 1.41).

CONCLUSION

Caesarean delivery including non-medically indicated maternal request caesarean delivery compared with vaginal delivery modestly increases childhood overweight risk.

Annexin 1: a glucocorticoid-inducible protein that modulates inflammatory pain

Annexin 1, a glucocorticoid (GC)-inducible protein, can play an important role via formyl peptide receptor like 1 (FPR2/ALX, also known as FPRL1) in inflammatory pain modulation. The aim of this review is to analyze different lines of evidence for the role of ANXA1 with different mechanisms on inflammatory pain and describe the profile of ANXA1 as a potential analgesic. A Medline (PUBMED) search using the terms 'Annexin 1 distribution OR expression, FPR2/ALX distribution OR expression, Annexin 1 AND pain, Annexin 1 AND FPR2/ALX AND pain' was performed. Articles with a publication date up to Nov. 1st, 2012 were included. The antinociception of ANXA1 has been evaluated in diverse pain models. It has been suggested that ANXA1 may exerts its action via: (1) inhibiting vital cytokines involved in pain transmission, (2) inhibiting neutrophil accumulation through preventing transendothelial migration via an interaction with formyl peptide receptors, (3) facilitating tonic opioid release from neutrophil in inflammatory site, (4) interrupting the peripheral nociceptive transmission by suppressing neuronal excitability. In general, ANXA1 is a potential mediator for anti-nociception and the role with its receptor constitute attractive targets for developing anesthesia and analgesic drugs, and their interaction may prove to be a useful strategy to treat inflammatory pain.

Prognostic value of the D-dimer test in oesophageal cancer during the perioperative period

BACKGROUND

There has been little research on the perioperative D-dimer levels in oesophageal cancer patients. Plasma D-dimer levels can be used to predict the outcome in cancer patients.

METHODS

A cancer group of 66 oesophageal cancer patients and a control group of 12 patients with benign disease were enrolled in this cohort study. The plasma D-dimer levels during the pre-operation and 3rd and 9th day post-operation periods were prospectively examined and analysed between the two groups. Plasma D-dimer levels were also compared with the clinicopathological characteristics and 3-year survival of the oesophageal cancer patients.

RESULTS

Plasma D-dimer levels increased in both groups after surgery, but they were significantly higher in the cancer group. In oesophageal cancer patients, pre-operation plasma D-dimer levels were significantly higher in TNM stage IV patients. Perioperative plasma D-dimer levels significantly increased after surgery, and the survival was shortened in those patients whose D-dimer levels on the 3rd and 9th post-operative day above the median. In addition, increased plasma D-dimer levels at the 3rd and 9th days after surgery were influenced by the patient's age.

CONCLUSION

In oesophageal cancer patients, D-dimer levels increased after surgery, and the increases were associated with poor outcomes.

Assessment of maternal anemia in rural Western China between 2001 and 2005: a two-level logistic regression approach

BACKGROUND

There are multiple adverse effects of anemia on human function, particularly on women. However, few researches are conducted on women anemia in rural Western China. This study mainly aims to investigate the levels and associated factors of maternal anemia between 2001 and 2005 in this region.

METHODS

6172 and 5372 mothers with children under three years old were selected from 8 provinces in 2001 and from 9 provinces in 2005 respectively in Western China by means of a multi-stage probability proportion to size sampling method (PPS). The blood samples were tested and related socio-demographic information was obtained through questionnaires. A two-level logistic regression model was employed to identify the determinants and provincial variations of women anemia in 2001 and 2005.

RESULTS

The results indicated that the crude prevalence of women anemia in 2005 was higher than the rate in 2001(45.7% vs 33.6%). Based on the nationwide census data in 2000, the age-standardized prevalence of women anemia in the study were obtained as 38.0% in 2001 and 50.0% in 2005 respectively. Two-level logistic model analysis showed that compared to the average, women were more likely to be anemic in Guangxi and Qinghai in 2001 as well as in Chongqing and Qinghai in 2005; that women from Minority groups had higher odds of anemia in contrast with Han; that women with higher parity, longer breastfeeding duration and higher socioeconomic level had a lower rate of anemia, while age of women was positively associated with anemia. The positive correlation between women anemia and altitude was also observed.

CONCLUSIONS

The study demonstrated that the burden of maternal anemia in rural Western China increased considerably between 2001 and 2005. The Chinese government should conduct integrated interventions on anemia of mothers in this region.

A functional variant in IL12B promoter modulates its expression and associates with increased risk of allergic asthma

The interleukin-12B (IL12B) gene encodes the p40 chain of IL-12, a pro-inflammatory cytokine that antagonizes Th2 phenotype and, hence, may have a critical role in the pathogenesis of allergic asthma. In this report, we describe the identification of a novel IL12B promoter polymorphism (T-to-A exchange) at position -536. The IL12B -536AA genotype was significantly associated with asthma in the Chinese populations (P=0.011, odds ratio=2.227). The risk-associated A allele was linked to reduced expression of IL12B mRNA levels and IL12B production in asthmatic patients. Luciferase reporter assay provided evidence that risk-associated A allele reduced the promoter activity of IL12B gene compared with those of the promoter containing the protective T allele. We further observed that decreasing binding effects between the risk alleles A of IL12B and CCAAT/enhancer binding protein alpha (C/EBPα) through A allele sequence mediated streptavidin-conjugated agarose pulldown and biotin-labelled A allele mediated electrophoretic mobility shift assay. We also observed additive effects of the risk alleles of IL12B and decreased mRNA levels of C/EBPα in asthmatic patients. Therefore, we postulated that the presence of -536A allele in IL12B promoter could predispose to the development of allergic asthma.

Small artery elasticity predicts future cardiovascular events in chinese patients with angiographic coronary artery disease

Arterial elasticity has been shown to predict cardiovascular disease (CVD) in apparently healthy populations. The present study aimed to explore whether arterial elasticity could predict CVD events in Chinese patients with angiographic coronary artery disease (CAD). Arterial elasticity of 365 patients with angiographic CAD was measured. During follow-up (48 months; range 6-65), 140 CVD events occurred (including 34 deaths). Univariate Cox analysis demonstrated that both large arterial elasticity and small arterial elasticity were significant predictors of CVD events. Multivariate Cox analysis indicated that small arterial elasticity remained significant. Kaplan-Meier analysis showed that the probability of having a CVD event/CVD death increased with a decrease of small arterial elasticity (P < .001, respectively). Decreased small arterial elasticity independently predicts the risk of CVD events in Chinese patients with angiographic CAD.

Evaluation of the Rural Primary Health Care project on undernutrition equity among children in rural Western China

BACKGROUND

The Chinese Ministry of Health (MOH) and the United Nations Children's Fund (UNICEF) carried out the Rural Primary Health Care Project (RPHC) with a government-led, province-level, integrated intervention that targeted children under 3 years old in rural areas of western China from 2001 to 2005. The objective of this study was to measure the effectiveness of the intervention on childhood nutrition.

METHODS

10 415 and 9916 children under 3 years old in 2001 and 2005, respectively, were selected in rural areas of western China. Stunting was used as the sole outcome variable to assess the child undernutrition change over time. The concentration index was used to assess the extent of the inequality of child undernutrition. Difference-in-difference estimation was used to evaluate the effects of the intervention on child undernutrition.

RESULTS

After the intervention, the proportion of child stunting decreased from 20.8% to 10.2%. The results from the difference-in-difference estimation with stunting adjusting for socio-demographic characteristics showed that the intervention had significantly improved the child stunting rate by 0.4%. Despite the decline in the undernutrition rate, the concentration indices for stunting in the intervention group decreased from -0.139 to -0.223 between 2001 and 2005.

CONCLUSION

This intervention project was effective in reducing childhood undernutrition rates to some extent in rural areas of western China. However, it seems that the project had a negative effect on the equity of undernutrition.

Socioeconomic status and children with intellectual disability in China

BACKGROUND

Intellectual disability (ID) accounts for 70% of all disabilities among children in China's Second National Sampling Survey on Disability. Although studies have shown a relationship between social class and ID in children, none have investigated the association of socioeconomic variables in Chinese children with mild or severe ID.

METHODS

Data for children aged 0-6 years with and without ID were abstracted from the Second National Sampling Survey on Disability in China, conducted in 2006. Crude odds ratios showed the effect of sociodemographic factors on mild and severe ID. Adjusted odds ratios (OR(a) ) (95% confidence intervals) estimated the independent effects of these factors.

RESULTS

For both mild and severe ID, risk of having ID increased with male sex, birth to a woman aged 35 years and older, lower maternal education, mother's older age at delivery, lower income and rural residence. After age, gender and parent disability were controlled, mothers aged 35 years and older were more likely to have a child with ID: mild ID, OR(a) 1.47 (1.15-1.88); severe ID, OR(a) 1.32 (1.00-1.73). There was an approximate increasing monotonic risk of severe ID with increasing socioeconomic disadvantage: lowest income, OR(a) 3.00 (2.19-4.12); low income, OR(a) 2.28 (1.63-3.19); lower middle income, OR(a) 1.72 (1.27-2.33); middle income, OR(a) 1.73 (1.28-2.36).

CONCLUSIONS

There is a significant relationship between sociodemographic factors and ID. Similar patterns were found for both mild and severe ID. Recommendations are given for preventing ID in Chinese children.

Annexin 1 exerts anti-nociceptive effects after peripheral inflammatory pain through formyl-peptide-receptor-like 1 in rat dorsal root ganglion

BACKGROUND

Annexin 1 (ANXA1) has analgesic effects in inflammatory pain. We aimed to investigate the anti-nociceptive role of ANXA1, at the dorsal root ganglion (DRG) level, through an interaction with formyl-peptide-receptor-like 1 (FPR2/ALX).

METHODS

Inflammatory pain was evoked by injecting complete Freund's adjuvant (CFA, 50 μl) into the hindpaw of male Sprague-Dawley rats. The distribution of ANXA1 and FPR2/ALX in L4/5 DRGs was evaluated by immunofluorescence. The expression of ANXA1 was measured by western blot. The involvement of FPR2/ALX in the anti-nociception of ANXA1 was investigated by thermal (irradiant heat) and mechanical (von Frey filament) pain tests with intrathecal (i.t.) ANXA1-derived peptide (Anxa1(2-26)), FPR2/ALX agonist 5(S)-6(R)-7-trihydroxyheptanoic-acid-methyl-ester (BML-111), and antagonist N-t-Boc-Phe-Leu-Phe-Leu-Phe (Boc1).

RESULTS

ANXA1 and FPR2/ALX localized in the satellite glial cells and neurones in L4/5 DRGs. CFA treatment (n=20) increased ANXA1 expression in L4/5 DRGs within 7 days (P<0.01). I.T. Anxa1(2-26) (20 and 100 µg µl(-1)) and BML-111 (10 and 100 nmol) reduced CFA-induced thermal and mechanical nociception within 48 h (n=40) (P<0.05). However, i.t. Boc1 10 µg intensified inflammatory pain (P<0.05) and reversed the anti-nociceptive effect of Anxa1(2-26) (n=25) (P<0.05). Moreover, ANXA1 expression increased in L4/5 DRGs after i.t. Anxa1(2-26) (20 µg µl(-1)) (P<0.05) and BML-111 (10 nmol) (P<0.01) but decreased after i.t. Boc1 (10 and 100 µg) alone (P<0.01) or Boc1 (10 µg) co-injection with Anxa1(2-26) (20 µg µl(-1)) (P<0.05).

CONCLUSIONS

Endogenous ANXA1 expression at the DRG level is involved in CFA-induced inflammatory pain, and i.t. ANXA1 20 µg µl(-1) produces its anti-nociceptive effect through FPR2/ALX.

Photonic generation of triangular waveform signals by using a dual-parallel Mach-Zehnder modulator

A photonic approach to generate triangular waveform signals is proposed and analyzed. With active bias control, two sub-MZMs (MZ-a and MZ-b) of a dual-parallel Mach-Zehnder modulator (DP-MZM) operate at minimum transmission point, leaving the main MZM (MZ-c) at quadrature transmission point. Triangular waveform can be observed by a parameter setting of modulation index. The proposal is first analyzed and then validated by simulation. The key significance of the scheme is that it is capable of generating triangular waveform signals via a sinusoid local oscillator.

Caesarean delivery on maternal request and childhood psychopathology: a retrospective cohort study in China

OBJECTIVE

To prospectively examine the association between mode of delivery and childhood psychopathology.

DESIGN

Retrospective cohort study.

SETTING

Eighteen counties and three cities in China.

POPULATION

A total of 4190 preschool children whose mothers were registered in a perinatal surveillance programme were assessed with the Child Behaviour Checklist (CBCL), an instrument to assess child emotional (internalising) and behavioural (externalising) problems.

METHODS

Differences in CBCL problem scores were analysed both quantitatively and categorically among children born by caesarean delivery on maternal request (CDMR), assisted vaginal delivery (AVD), and spontaneous vaginal delivery (SVD).

MAIN OUTCOME MEASURES

The CBCL total, externalising, and internalising scores.

RESULTS

There were significant differences in the mean scores of total (20.9, 23.0, and 25.0), externalising (7.6, 8.4, and 9.1), and internalising (4.7, 5.2, and 5.6) problems among children born by CDMR, SVD, and AVD, after adjusting for potential confounding factors (P = 0.007, 0.014, and 0.031). Children born by AVD were more likely than those born by SVD to have total (OR 1.43; 95% CI 1.10-1.86), externalising (OR 1.46; 95% CI 1.11-1.92), and internalising (OR 1.41; 95% CI 1.08-1.84) scores in the highest quartile, whereas children born by CDMR were less likely to have externalising scores in the highest quartile (OR 0.64; 95% CI 0.42-0.97). Furthermore, there were significant increasing linear trends on all problem scores, and in the odds of being in the highest quartile, from children born by CDMR to those born by SVD and AVD.

CONCLUSION

The likelihood of childhood psychopathological problems may be the lowest in children born by CDMR, followed by those born by SVD, whereas the highest probability was observed in those born by AVD.

An anti-Axl monoclonal antibody attenuates xenograft tumor growth and enhances the effect of multiple anticancer therapies

Axl is expressed in various types of cancer and is involved in multiple processes of tumorigenesis, including promoting tumor cell growth, migration, invasion, metastasis as well as angiogenesis. To evaluate further the mechanisms involved in the expression/activation of Axl in various aspects of tumorigenesis, especially its roles in modulating tumor stromal functions, we have developed a phage-derived mAb (YW327.6S2) that recognizes both human and murine Axl. YW327.6S2 binds to both human and murine Axl with high affinity. It blocks the ligand Gas6 binding to the receptor, downregulates receptor expression, inhibits receptor activation and downstream signaling. In A549 non-small-cell lung cancer (NSCLC) and MDA-MB-231 breast cancer models, YW327.6S2 attenuates xenograft tumor growth and potentiates the effect of anti-VEGF treatment. In NSCLC models, YW327.6S2 also enhances the effect of erlotinib and chemotherapy in reducing tumor growth. Furthermore, YW327.6S2 reduces the metastasis of MDA-MB-231 breast cancer cells to distant organs. YW327.6S2 induces tumor cell apoptosis in NSCLC, reduces tumor-associated vascular density and inhibits the secretion of inflammatory cytokines and chemokines from tumor-associated macrophages in the breast cancer model. In conclusion, anti-Axl mAb can enhance the therapeutic efficacy of anti-VEGF, EGFR small-molecule inhibitors as well as chemotherapy. Axl mAb affects not only tumor cells but also tumor stroma through its modulation of tumor-associated vasculature and immune cell functions.

Finite-element analysis of contact between elastic self-affine surfaces

Finite-element methods are used to study nonadhesive, frictionless contact between elastic solids with self-affine surfaces. We find that the total contact area rises linearly with the load at small loads. The mean pressure in the contact regions is independent of load and proportional to the root-mean-square slope of the surface. The constant of proportionality is nearly independent of the Poisson ratio and roughness exponent and lies between previous analytic predictions. The contact morphology is also analyzed. Connected contact regions have a fractal area and perimeter. The probability of finding a cluster of area a(c) drops as a(-tau )(c ) where tau increases with a decrease in roughness exponent. The distribution of pressures shows an exponential tail that is also found in many jammed systems. These results are contrasted to simpler models and experiments.

Transcriptional repressor of vasoactive intestinal peptide receptor mediates repression through interactions with TFIIB and TFIIEbeta

The transcriptional repressor for rat vasoactive-intestinal-polypeptide receptor 1 (VIPR-RP) is a recently characterized transcription factor that belongs to a family of proteins, which include components of the DNA replication factor C complex. In this study, I investigated the mechanisms by which VIPR-RP represses transcription. I show here that transcriptional repression by VIPR-RP is mediated by a histone deacetylase-independent mechanism. I provide evidence that VIPR-RP makes direct physical contacts with two proteins of the basal transcription apparatus, the transcription factors TFIIB and TFIIEbeta. The interaction with TFIIB is mediated by the N-terminal 180 amino acids, whereas the interactive domain with TFIIEbeta is located between residues 367 and 527 of VIPR-RP. Using gel mobility-shift assays I demonstrated that interaction between VIPR-RP and TFIIB prevents the recruitment of TFIIB into a DNA-TATA-box-binding protein complex. My results indicate that VIPR-RP mediates transcriptional repression through direct interactions with the general transcription machinery.

Reproductive deficiencies in transgenic mice expressing the rat inhibin alpha-subunit gene

Inhibin is an important modulator of reproductive function at both the endocrine level, through its regulation of pituitary FSH biosynthesis, and at the paracrine and autocrine levels, as an intragonadal regulatory factor. To investigate the in vivo actions of inhibin in FSH regulation and gonadal function, transgenic mice that overexpress the rat inhibin alpha-subunit gene were generated. A transgene that includes the mouse metallothionein-I gene promoter (MT-alpha) fused to the rat inhibin alpha-subunit precursor coding sequences was used to produce three lines of transgenic mice. Transgene mRNA is expressed in numerous tissues, including the pituitary, liver, testis, ovary, and kidney. Inhibin alpha-subunit protein was also increased in transgenic pituitary and ovary. Serum inhibin alpha-subunit levels are highly increased compared with control mice. Inhibin beta(A)- and beta(B)-subunit protein amounts are lower in transgenic ovaries compared with wild type, although serum levels of activin A are not significantly reduced in transgenic female mice. FSH levels are reduced in both male and female transgenic mice, whereas LH levels are increased in MT-alpha female mice. MT-alpha transgenic females are subfertile and exhibit a 52% reduction in litter size compared with wild-type females. The smaller litter size of MT-alpha female mice was correlated with a reduction in the number of oocytes ovulated during a normal cycle. Treatment of the transgenic females with exogenous gonadotropins resulted in an ovulation rate similar to that of stimulated wild-type animals, suggesting that altered gonadotropin levels may be responsible for the decreased ovulation rates. MT-alpha transgenic male mice are fertile and sire litters of equivalent size to those sired by wild-type males, despite an approximately 50% reduction in sperm numbers. These results indicate that overexpression of the rat inhibin alpha-subunit gene in mice leads to a disruption of the normal inhibin-to-activin ratio and to reproductive deficiencies, and they support the hypothesis that inhibin and activin act to regulate FSH secretion in vivo and are essential for normal gonadal function.

Autoregulation of the human liver X receptor alpha promoter

Previous work has implicated the nuclear receptors liver X receptor alpha (LXR alpha) and LXR beta in the regulation of macrophage gene expression in response to oxidized lipids. Macrophage lipid loading leads to ligand activation of LXRs and to induction of a pathway for cholesterol efflux involving the LXR target genes ABCA1 and apoE. We demonstrate here that autoregulation of the LXR alpha gene is an important component of this lipid-inducible efflux pathway in human macrophages. Oxidized low-density lipoprotein, oxysterols, and synthetic LXR ligands induce expression of LXR alpha mRNA in human monocyte-derived macrophages and human macrophage cell lines but not in murine peritoneal macrophages or cell lines. This is in contrast to peroxisome proliferator-activated receptor gamma (PPAR gamma)-specific ligands, which stimulate LXR alpha expression in both human and murine macrophages. We further demonstrate that LXR and PPAR gamma ligands cooperate to induce LXR alpha expression in human but not murine macrophages. Analysis of the human LXR alpha promoter led to the identification of multiple LXR response elements. Interestingly, the previously identified PPAR response element (PPRE) in the murine LXR alpha gene is not conserved in humans; however, a different PPRE is present in the human LXR 5'-flanking region. These results have implications for cholesterol metabolism in human macrophages and its potential to be regulated by synthetic LXR and/or PPAR gamma ligands. The ability of LXR alpha to regulate its own promoter is likely to be an integral part of the macrophage physiologic response to lipid loading.