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Intrinsic disorder is a common structural characteristic of proteins and a central player in the biochemical processes of species. However, the role of intrinsic disorder in the evolution of plant-pathogen interactions is rarely investigated. Here, we explored the role of intrinsic disorder in the development of the pathogenicity in the RXLR AVR2 effector of Phytophthora infestans. We found AVR2 exhibited high nucleotide diversity generated by point mutation, early-termination, altered start codon, deletion/insertion, and intragenic recombination and is predicted to be an intrinsically disordered protein. AVR2 amino acid sequences conferring a virulent phenotype had a higher disorder tendency in both the N- and C-terminal regions compared with sequences conferring an avirulent phenotype. In addition, we also found virulent AVR2 mutants gained one or two short linear interaction motifs, the critical components of disordered proteins required for protein-protein interactions. Furthermore, virulent AVR2 mutants were predicted to be unstable and have a short protein half-life. Taken together, these results support the notion that intrinsic disorder is important for the effector function of pathogens and demonstrate that SLiM-mediated protein-protein interaction in the C-terminal effector domain might contribute greatly to the evasion of resistance-protein detection in P. infestans.

Lung adenocarcinoma (LUAD) is one of several malignant tumours with the highest incidence rates. Currently, there is an urgent need for effective diagnostic and therapeutic targets for LUAD in clinical practice. Numerous studies have shown that there may be differences in the development pattern of LUAD between male and female patients, leading to the need for differential treatment. At the same time, previous studies have shown that competitive endogenous (ce)RNA plays an important role in the development of LUAD, but there is no relevant research on whether there is a gender difference in the ceRNA network of LUAD. In this study, we constructed gender-independent, male-specific, and female-specific ceRNA networks using RNA sequencing results from TCGA database. Subsequently, through analysis of the core genes of the ceRNA network, we determined that the male and female ceRNA networks indeed display different features. In addition, we also found that the osteoclast-associated receptor (OSCAR) gene was a potential diagnostic target for detecting LUAD in females, and that increased expression of this gene promoted the proliferation and migration of A549 and H1975 LUAD cell lines; more specifically, A549 and H1975 are male and female LUAD cell lines, respectively. This suggests that the OSCAR gene has the potential to serve as target molecule for the diagnosis and treatment of female-specific LUADs.

Background The evidence for different frequencies of acupuncture treatment in postprandial distress syndrome (PDS) is insufficient. This study determined whether 3 sessions per week of acupuncture treatment are superior to 1 session per week for symptomatic outcomes in PDS. Methods This 16-week randomized clinical pilot trial was conducted in an outpatient setting in China. Patients with PDS were randomly assigned to receive 3 sessions per week of acupuncture (group H) or 1 session per week of acupuncture (group L) for 4 weeks. The primary outcome was the complete elimination of core symptoms at week 4. Secondary outcomes included overall treatment efficacy, dyspepsia symptoms, quality of life, anxiety, and depression. Key results Sixty patients were randomized of whom 53 (88.3%) completed this trial. The complete elimination rate of core symptoms was 26.7% (95% CI 12.3%-45.9%) in group H and 10.0% (95% CI 2.1%-26.5%) in group L at week 4 (P = .095). There was a significant difference between H and group L at weeks 8, 12, and 16 (P = .038, .02, and .02). All secondary outcomes were better in group H at all time points. No serious adverse events occurred in either groups. Conclusions This trial showed that acupuncture, at 3 sessions per week, tended to improve symptoms and the quality of life among patients with PDS as compared to once a week. Acupuncture treatment for 4 weeks was feasible and safe. A larger sample, multicenter, randomized controlled trial of acupuncture for PDS appears to be justified in the future.

Background Electroacupuncture (EA) is widely used in various gastrointestinal diseases around the world, including POI. Here, we investigated different therapeutic effects of EA using lower limb and abdomen acupoints. Methods Intestinal manipulation was performed in 88 mice, and eight mice underwent a sham operation. Forty mice were randomly divided into model group and four EA groups receiving stimulation at ST36 (2, 10, 30, 100 Hz). The most effective frequency was then used in the following experiments. Forty-eight mice were randomly divided into six groups receiving EA treatment at ST37, ST39, ST25, CV4, CV12, and a non-acupuncture point. Gastrointestinal motility and plasma TNF-α, IL-6 were evaluated in all mice. The local immune response and α-smooth muscle actin (α-SMA) expression were assessed by immunofluorescence, ELISA, and HE staining. Results ST36 stimulated with 10 or 30 Hz EA significantly increased the gastrointestinal motility and attenuated peripheral inflammation; however, ST36 stimulated with 2 or 100 Hz did not induce any effect. The therapeutic effects on motility and inflammation of 10 Hz EA in the ST36 group were similar in the ST36, ST37, ST39, or CV4 groups, but when applied to ST25, CV12 or non-acupoint had no significant differences. EA at ST36, ST37, ST39, or CV4 significantly inhibited local MPO activity, immune cells infiltration, and increased α-SMA. Conclusions EA at lower limb and abdomen acupoints with the same stimulation parameters had different therapeutic effects on postoperative dysmotility and inflammation. Furthermore, EA protected SMC to improve gastrointestinal transit by reducing local inflammation in the intestinal musculature in POI.

Calmodulin (CaM) is a highly conserved calcium sensor protein associated with chilling tolerance in living organisms. It has four EF-hand domains for binding of four Ca2+, two of them located in the N-terminus, and the other two in the C-terminus. A notothenioid CaM gene fragment (CaMm), which only codes for N-terminus of CaM (with two EF-hand domains), was introduced into Nicotiana benthamiana. Effects of its overexpression on chilling tolerance in plants were explored. During 4◦C or 0◦C chilling treatment, both CaMm and CaM transgenic plants showed higher PSII maximum quantum yield, actual quantum yield, and soluble protein content, lower electrolyte leakage and malondialdehyde content than that of the control. The changes in these physiological indices were comparable between the CaMm and CaM transgenic plants during the treatments. These results indicate that the N-terminus of calmodulin is likely the key functional domain involved in the adaptive response to cold stress.

Background After years of periconceptional folic acid supplementation, the prevalence of neural tube defects (NTDs) remains stable following the remarkable reduction observed immediately after the fortification practice. There is accumulating evidence that folate receptor (FR) autoimmunity may play a role in the etiology of folate-sensitive NTDs. Methods From 2011 to 2013, 118 NTD cases and 242 healthy controls were recruited from a population-based birth defects surveillance system in Northern China. Enzyme-linked immunosorbent assay was used to measure FR autoantibodies in maternal and cord blood. Logistic regression models were used to estimate the odds ratios (OR) and 95% confidence intervals (95% CI). Results Plasma FR autoantibodies levels were significantly elevated in mothers of infants with NTDs compared with mothers of healthy controls. Using the lowest tertile as the referent group, 2.20-fold (95% CI, 0.71–6.80) and 5.53-fold increased odds (95% CI, 1.90–16.08) of NTDs were observed for the second and third tertile of immunoglobulin G (IgG), respectively, and the odds of NTDs for each successive tertile of IgM was 0.98 (95% CI, 0.35–2.75) and 3.49 (95% CI, 1.45–8.39), respectively. A dose–response relationship was found between FR autoantibodies levels and risk of NTDs (P < 0.001 for IgG, P = 0.002 for IgM). The same pattern was observed in both subtypes of spina bifida and anencephaly. No significant difference in levels of cord blood FR autoantibodies was observed. Conclusion Higher levels of FR autoimmunity in maternal plasma are associated with elevated risk of NTDs in a dose–response manner. Birth Defects Research (Part A) 106:685–695, 2016. © 2016 Wiley Periodicals, Inc.

Changes in growth and distribution of inorganic mineral elements and organic active substances in seedlings of A. vera were examined under treatments of −0.44 and −0.88 MPa polyethylene glycol 6000 (PEG) and corresponding isosmotic sodium chloride (NaCl). All stress treatments inhibited plant growth, with NaCl severely inhibiting the growth of the seedlings than PEG. However, leaf biomass did not change significantly. The nitrogen concentration under PEG was maintained higher than that under NaCl. Salinity caused more severe ionic imbalance than dehydration. However, when the concentration of NaCl was increased, ion homeostasis was maintained. Stressors induced an increase in aloin concentration in leaves, especially in young leaves. Polysaccharide concentrations in leaves did not change under dehydration. However, the polysaccharide concentration decreased in the middle and base leaves under NaCl. A. vera exhibited high adaptability to suitable osmotic stress, which increases its main active ingr...

Inflammation-dominated sympathetic sprouting adjacent to the necrotic region following myocardial infarction (MI) has been implicated in the etiology of arrhythmias resulting in sudden cardiac death; however, the mechanisms responsible remain to be elucidated. Although being a key immune mediator, the role of Notch has yet to be explored. We investigated whether Notch regulates macrophage responses to inflammation and affects cardiac sympathetic reinnervation in rats undergoing MI. MI was induced by coronary artery ligation. A high level of Notch intracellular domain was observed in the macrophages that infiltrated the infarct area at 3 days post-MI. The administration of the Notch inhibitor N-N-(3,5-difluorophenacetyl-l-alanyl)-S-phenylglycine-t-butyl ester (DAPT) (intravenously 30 min before MI and then daily until death) decreased the number of macrophages and significantly increased the M2 macrophage activation profile in the early stages and attenuated the expression of nerve growth factor (NGF). Eventually, NGF-induced sympathetic hyperinnervation was blunted, as assessed by the immunofluorescence of tyrosine hydroxylase. At 7 days post-MI, the arrhythmia score of programmed electric stimulation in the vehicle-treated infarcted rats was higher than that in rats treated with DAPT. Further deterioration in cardiac function and decreases in the plasma levels of TNF-α and IL-1β were also detected. In vitro studies revealed that LPS/IFN-γ upregulated the surface expression of NGF in M1 macrophages in a Notch-dependent manner. We concluded that Notch inhibition during the acute inflammatory response phase is associated with the downregulation of NGF, probably through a macrophage-dependent pathway, thus preventing the process of sympathetic hyperinnervation.

Background Increasing evidence suggest that active smoking is a risk factor for hypertension, but little is known about the effects of passive smoking on this condition. In China, female passive smoking is widespread and severe due to the high proportion of men who smoke, particularly in rural areas. This study assessed whether passive smoking is associated with increased risk of hypertension among nonsmoking women in rural China. Methods A total of 392 nonsmoking women from a rural area of Shanxi Province (northern China) participated in this cross-sectional study. Data on female passive smoking, and other factors known to influence hypertension, were collected during face-to-face interviews. Logistic regression was used to evaluate the association analyses after adjusting for potential confounders. Results In total, 162 of the 392 participants were hypertensive (41.3%); 118 participants (30.1%) reported exposure to passive smoking, of whom 88.4% were exposed to smoke in the home. After adjusting for age, BMI, education, occupation, drinking status, physical activity, and menopause status, passive smoking conferred an approximately two-fold risk increase of hypertension (adjusted odds ratio = 1.99, 95% confidence interval 1.16, 3.39). The adjusted odds ratios for passive smoking exposure levels of one to three, four to six, and more than six occasions per week were 1.01 (0.39-2.62), 2.57 (1.05-6.30), and 2.59 (1.18-5.69), respectively. Conclusion In rural areas of northern China, female passive smoking in the home is prevalent. Frequent exposure to secondhand smoke is a risk factor for hypertension among nonsmoking women, which suggests that measures should be taken to prevent passive smoking among this population.

Excessive use of nitrogen (N) fertilizer has increased ammonium (NH4+ ) accumulation in many paddy soils to levels that reduce rice vegetative biomass and yield. Based on studies of NH4+ toxicity in rice (Oryza sativa, Nanjing 44) seedlings cultured in agar medium, we found that NH4+ concentrations above 0.75 mM inhibited the growth of rice and caused NH4+ accumulation in both shoots and roots. Use of excessive NH4+ also induced rhizosphere acidification and inhibited the absorption of K, Ca, Mg, Fe and Zn in rice seedlings. Under excessive NH4+ conditions, exogenous γ-aminobutyric acid (GABA) treatment limited NH4+ accumulation in rice seedlings, reduced NH4+ toxicity symptoms and promoted plant growth. GABA addition also reduced rhizosphere acidification and alleviated the inhibition of Ca, Mg, Fe and Zn absorption caused by excessive NH4+ . Furthermore, we found that the activity of glutamine synthetase/NADH-glutamate synthase (GS; EC 6.3.1.2/NADH-GOGAT; EC1.4.1.14) in root increased gradually as the NH4+ concentration increased. However, when the concentration of NH4+ is more than 3 mM, GABA treatment inhibited NH4+ -induced increases in GS/NADH-GOGAT activity. The inhibition of ammonium assimilation may restore the elongation of seminal rice roots repressed by high NH4+ . These results suggest that mitigation of ammonium accumulation and assimilation is essential for GABA-dependent alleviation of ammonium toxicity in rice seedlings.

Background/Aim: Triple-negative breast cancer (TNBC) represents a particular clinical challenge because these cancers do not respond to endocrine therapy or other available targeted agents. The lack of effective agents and obvious targets are major challenges in treating TNBC. In this study we explored the cytostatic effect of thiazole ring containing antibiotic drug thiostrepton on TNBC cell lines and investigated the molecular mechanism. Methods: Cell viability was measured by MTT assay. Cell surface marker was monitored by FCM. Western blot was applied to assess the protein expression levels of target genes. Results: We found that thiostrepton remarkably suppressed the CD44+/CD24- stem-like population and sphere forming capacity of TNBC cell lines. Notably, we showed for the first time that thiostrepton exerted its pharmacological action by targeting sonic hedgehog (SHH) signaling pathway. Thiostrepton repressed SHH ligand expression and reduced Gli-1 nuclear localization in TNBC cell line. Furthermore, the downstream target of SHH signaling undergone dose-dependent, rapid, and sustained loss of mRNA transcript level after thiostrepton treatment. Finally, we showed that SHH ligand was essential for maintaining CD44+/CD24- stem-like population in TNBC cell line. Conclusion: We conclude that thiostrepton suppresses the CD44+/CD24- stem-like population through inhibition of SHH signaling pathway. Our results give a new insight into the mechanism of thiostrepton anti-tumor activity and suggest thiostrepton as a promising agent that targets hedgehog signaling pathway in TNBC.

Background: Compelling evidence suggests that SIRT1, NAD+-dependent class III protein deacetylase, plays an important role in the prevention and treatment of atherosclerosis by counteracting inflammation. Cluster of differentiation 40 (CD40), as a pro-inflammatory cytokine, has been shown to participate in the pathophysiology of atherosclerosis. The relationship between SIRT1 and CD40, however, remained elusive. The present study was thus designed to explore the potential effect of SIRT1 on CD40 expression induced by tumor necrosis factor-α (TNF-α) and to disclose the underlying mechanism in CRL-1730 endothelial cells. Methods: mRNA and protein expressions were identified by quantitative real-time PCR and Western blot respectively. Subcellular localization of SIRT1 was detected by immunofluorescence analysis. SIRT1 small-interfering RNA (siRNA) was carried out for mechanism study. Results: TNF-α reduced SIRT1 expression and induced CD40 expression in CRL-1730 endothelial cells in a time- and concentration- dependent manner. Pretreatment with resveratrol (a potent SIRT1 activator) inhibited TNF-α-induced CD40 expression, while pretreatment with nicotinamide (class b HDACs inhibitor nicotinamide) or sirtinol (a known SIRT1 inhibitor), especially SIRT1 siRNA significantly augmented TNF-α-induced CD40 expression. The frther sudy idicated that PDTC (NF-ĸB inhibitor) pretreatment attenuated TNF-α-induced CD40 expression, and SIRT1 siRNA significantly augmented TNF-α-induced acetylated-NF-ĸB p65 (Lys310) expression. Conclusion: The present study provides the direct evidence that SIRT1 can inhibit TNF-α- induced CD40 expression in CRL-1730 endothelial cells by deacetylating the RelA/p65 subunit of NF-ĸB at lysine 310, which provides new insights into understanding of the anti-inflammatory and anti-athroscerotic actions of SIRT1.

Pulmonary hypertension (PH) is associated with profound vascular remodeling and alterations in Ca2+ homeostasis in pulmonary arterial smooth muscle cells (PASMCs). Previous studies show that canonical transient receptor potential (TRPC) genes are upregulated and store-operated Ca2+ entry (SOCE) is augmented in PASMCs of chronic hypoxic rats and patients of pulmonary arterial hypertension (PAH). Here we further examine the involvement of TRPC and SOCE in PH with a widely used rat model of monocrotaline (MCT)-induced PAH. Rats developed severe PAH, right ventricular hypertrophy, and significant increase in store-operated TRPC1 and TRPC4 mRNA and protein in endothelium-denuded pulmonary arteries (PAs) 3 wk after MCT injection. Contraction of PA and Ca2+ influx in PASMC evoked by store depletion using cyclopiazonic acid (CPA) were enhanced dramatically, consistent with augmented SOCE in the MCT-treated group. The time course of increase in CPA-induced contraction corresponded to that of TRPC1 expression. Endothelin-1 (ET-1)-induced vasoconstriction was also potentiated in PAs of MCT-treated rats. The response was partially inhibited by SOCE blockers, including Gd3+, La3+, and SKF-96365, as well as the general TRPC inhibitor BTP-2, suggesting that TRPC-dependent SOCE was involved. Moreover, the ET-1-induced contraction and Ca2+ response in the MCT group were more susceptible to the inhibition caused by the various SOCE blockers. Hence, our study shows that MCT-induced PAH is associated with increased TRPC expression and SOCE, which are involved in the enhanced vascular reactivity to ET-1, and support the hypothesis that TRPC-dependent SOCE is an important pathway for the development of PH.

Root hairs are plastic in response to nutrient supply, but relatively little is known about their development under low ammonium (NH4(+)) conditions. This study showed that reducing NH4(+) for 3 days in wild-type Arabidopsis seedlings resulted in drastic elongation of root hairs. To investigate the possible mediation of ethylene and auxin in this process, seedlings were treated with 2,3,5-triiodobenzoic acid (TIBA, auxin transport inhibitor), 1-naphthylphthalamic acid (NPA, auxin transport inhibitor), p-chlorophenoxy isobutyric acid (PCIB, auxin action inhibitor), aminoethoxyvinylglycine (AVG, chemical inhibitor of ethylene biosynthesis), or silver ions (Ag(+), ethylene perception antagonist) under low NH4(+) conditions. Our results showed that TIBA, NPA and PCIB did not inhibit root hair elongation under low NH4(+) conditions, while AVG and Ag(+) completely inhibited low NH4(+)-induced root hair elongation. This suggested that low NH4(+)-induced root hair elongation was dependent on the ethylene pathway, but not the auxin pathway. Further genetic studies revealed that root hair elongation in auxin-insensitive mutants was sensitive to low NH4(+) treatment, but elongation was less sensitive in ethylene-insensitive mutants than wild-type plants. In addition, low NH4(+)-induced root hair elongation was accompanied by reactive oxygen species (ROS) accumulation. Diphenylene iodonium (DPI, NADPH oxidase inhibitor) and dimethylthiourea (DMTU, ROS scavenger) inhibited low NH4(+)-induced root hair elongation, suggesting that ROS were involved in this process. Moreover, ethylene acted together with ROS to modulate root hair elongation under low NH4(+) conditions. These results demonstrate that a signaling pathway involving ethylene and ROS participates in regulation of root hair elongation when Arabidopsis seedlings are subjected to low NH4(+) conditions.

The world heritage of Huangshan is located in the east-central China. In order to obtain a better overview of biodiversity in Huangshan, we investigated the diversity of arbuscular mycorrhizal fungi in the soil of Huangshan. Forty-two rhizosphere soil samples were collected and 989 arbuscular mycorrhizal fungal spore samples were obtained using the wet-sieving method. Twenty-five species of arbuscular mycorrhizal fungi were identified from the collections. The species were of the genera Acaulospora (6 species), Entrophospora (1 species), Glomus (16 species) and Scutellospora (2 species). Acaulospora and Glomus were dominant at the study site. The arbuscular mycorrhizal fungi spore density ranged from 45 to 3,250 per 100 g soil (average 839), and the species richness of arbuscular mycorrhizal fungi ranged from 1 to 9 (average 4.2) per soil sample. Shannon–Wiener index and Simpson’s index were calculated to evaluate the arbuscular mycorrhizal fungal diversity. The diversity of arbuscular mycorrhizal fungal community in the subtropical forest of Huangshan may be the result of mutual selection between arbuscular mycorrhizal fungi and the ecological environment.

1. Chronic heart failure (CHF) is often accompanied by renal dysfunction. Exercise training may relieve the symptomatic burden and improve the overall prognosis of CHF. In the present study, the effects of exercise training on renal function and renal aquaporin (AQP)-2 expression in CHF rats were examined to determine whether exercise training could relieve renal dysfunction in CHF rats. 2. Male Sprague-Dawley rats were divided into three groups: sham, sedentary CHF (Sed-CHF) and exercise training CHF (Ex-CHF) groups. Cardiorenal function was assessed in each group by haemodynamic measurement and ultraviolet spectrophotometry. Pathological changes in cardiac and renal tissues were evaluated histologically and the collagen volume fraction (CVF) was calculated. The expressions of AQP-2 and β-tubulin were determined by western blotting and immunohistochemistry. 3. The Sed-CHF rats were found to have increased left ventricular end-diastolic pressure (LVEDP) and CVF in the heart compared with sham rats. Exercise training decreased LVEDP and CVF values in Ex-CHF rats. The Sed-CHF rats were found to have increased serum levels of creatinine (sCr), blood urea nitrogen (BUN) and arginine vasopressin (AVP), as well as increased CVF in the kidney, compared with sham rats. Exercise training decreased levels of sCr, BUN, AVP and CVF in Ex-CHF rats. Moreover, exercise training decreased AQP-2 and β-tubulin protein expression in the kidney of CHF rats. 4. The results suggest that exercise training can significantly improve the renal dysfunction in CHF rats and that the underlying mechanism may be related to water reabsorption and preventing changes to the cytoskeleton.

Background/Aim: P21, a multifunctional cell cycle-regulatory molecule, regulates apoptotic cell death. In this study we examined the effect of altered p21 expression on the sensitivity of acute myeloid leukemia cells in response to HDAC inhibitor SAHA treatment and investigated the underlying mechanism. Methods: Stably transfected HL60 cell lines were established in RPMI-1640 with supplementation of G-418. Cell viability was measured by MTT assay. Western blot was applied to assess the protein expression levels of target genes. Cell apoptosis was monitored by AnnexinV-PE/7AAD assay. Results: We showed HL60 cells that that didn't up-regulate p21 expression were more sensitive to SAHA-mediated apoptosis than NB4 and U937 cells that had increased p21 level. Enforced expression of p21 in HL60 cells reduced sensitivity to SAHA and blocked TRAIL-mediated apoptosis. Conversely, p21 silencing in NB4 cells enhanced SAHA-mediated apoptosis and lethality. Finally, we found that combined treatment with SAHA and rapamycin down-regulated p21 and enhanced apoptosis in AML cells. Conclusion: We conclude that up-regulated p21 expression mediates resistance to SAHA via inhibition of TRAIL apoptotic pathway. P21 may serve as a candidate biomarker to predict responsiveness or resistance to SAHA-based therapy in AML patients. In addition, rapamycin may be an effective agent to override p21-mediated resistance to SAHA in AML patients.

End-stage renal disease patients are known to be in a state of chronic low-grade inflammation and to have high infection-related morbidity and mortality. However, the precise mechanisms are not understood. The purpose of this study was to determine the mechanisms underlying chronic low-grade inflammation and defects in innate immune responses in hemodialysis (HD) patients.In 33 HD patients, we measured the basal status of toll-like receptor 4 (TLR4) positivity in the CD14-positive monocyte population in the peripheral blood (not strong, i.e., CD14(low)), with plasma levels of tumor necrosis factor (TNF)-α and interleukin (IL)-1β, IL-6, IL-8, IL-10, and IL-12p70 compared with 22 healthy controls. After stimulation by lipopolysaccharide (LPS), the plasma cytokine response was also compared.In the basal state, the percentage of peripheral blood TLR4(+)CD14(low) monocytes and plasma cytokines were significantly higher in HD patients (p 0.05), suggesting that preactivated primed monocytes might be responsible for the chronic inflammatory state in HD patients. However, upon LPS challenge, the fold increase in plasma cytokine response was significantly reduced in HD patients (p 0.05) compared with controls. More importantly, the fold increase of these cytokines showed a positive correlation with plasma albumin (p 0.05) and a negative correlation with C-reactive protein (CRP) (p 0.05), suggesting the presence of a possible link between chronic low-grade inflammation and suboptimal innate immune response.Chronic low-grade inflammation due to preactivated peripheral blood CD14(+) leukocyte subset might be a mechanism for impaired innate immune responses, thus resulting in the high rates of infection-related morbidity and mortality observed in HD patients.

Osteoporosis is a major public health problem, mainly characterized by low bone mineral density (BMD). BMD is a complex trait that is determined by multiple genes. Insulin-like growth factor I (IGF-I) is an important growth factor of bone and thus IGF-I gene has been considered as an attractive candidate gene for osteoporosis. A few studies on the relationship between variants of the IGF-I gene and BMD variation, via traditional association and/or linkage methods, have yielded conflicting results. In this study, we simultaneously tested association and/or linkage of a cytosine-adenine (CA) repeat polymorphism at 1 kb upstream of the transcription initiation site of the IGF-I gene with BMD variation in a large cohort of premenopausal Chinese women. A total of 1263 subjects from 402 Chinese nuclear families were examined. Each family consists of both parents and at least one daughter aged between 20 and 45 years. BMDs (g/cm 2 ) at the lumbar spine and hip were measured using dual-energy X-ray absorptiometry (DXA). Applying the QTDT (quantitative transmission disequilibrium tests) progam, we did not find significant evidence of association or linkage between the CA repeat polymorphism of the IGF-I gene and BMD variation at any skeletal site. Our data do not support the IGF-I gene having major effect on BMD variation in premenopausal Chinese women.