An Insight into the Difficulties in the Discovery of Specific Biomarkers of Limbal Stem Cells.

Keeping the integrity and transparency of the cornea is the most important issue to ensure normal vision. There are more than 10 million patients going blind due to the cornea diseases worldwide. One of the effective ways to cure corneal diseases is corneal transplantation. Currently, donations are the main source of corneas for transplantation, but immune rejection and a shortage of donor corneas are still serious problems. Graft rejection could cause transplanted cornea opacity to fail. Therefore, bioengineer-based corneas become a new source for corneal transplantation. Limbal stem cells (LSCs) are located at the basal layer in the epithelial palisades of Vogt, which serve a homeostatic function for the cornea epithelium and repair the damaged cornea. LSC-based transplantation is one of the hot topics currently. Clinical data showed that the ratio of LSCs to total candidate cells for a transplantation has a significant impact on the effectiveness of the transplantation. It indicates that it is very important to accurately identify the LSCs. To date, several putative biomarkers of LSCs have been widely reported, whereas their specificity is controversial. As reported, the identification of LSCs is based on the characteristics of stem cells, such as a nuclear-to-cytoplasm ratio (N/C) ≥ 0.7, label-retaining, and side population (SP) phenotype. Here, we review recently published data to provide an insight into the circumstances in the study of LSC biomarkers. The particularities of limbus anatomy and histochemistry, the limits of the current technology level for LSC isolation, the heterogeneity of LSCs and the influence of enzyme digestion are discussed. Practical approaches are proposed in order to overcome the difficulties in basic and applied research for LSC-specific biomarkers.

Practical Application of Aptamer-Based Biosensors in Detection of Low Molecular Weight Pollutants in Water Sources.

Water pollution has become one of the leading causes of human health problems. Low molecular weight pollutants, even at trace concentrations in water sources, have aroused global attention due to their toxicity after long-time exposure. There is an increased demand for appropriate methods to detect these pollutants in aquatic systems. Aptamers, single-stranded DNA or RNA, have high affinity and specificity to each of their target molecule, similar to antigen-antibody interaction. Aptamers can be selected using a method called Systematic Evolution of Ligands by EXponential enrichment (SELEX). Recent years we have witnessed great progress in developing aptamer selection and aptamer-based sensors for low molecular weight pollutants in water sources, such as tap water, seawater, lake water, river water, as well as wastewater and its effluents. This review provides an overview of aptamer-based methods as a novel approach for detecting low molecular weight pollutants in water sources.

The circadian rhythm of arterial blood pressure in Alzheimer disease (AD) patients without hypertension.

OBJECTIVES: The circadian rhythm (CR) of arterial blood pressure (ABP) in Alzheimer disease (AD) patients was examined in a case-control clinical study. METHODS: This study was constructed using the case-control method and investigates non-hypertensive AD patients, compared with normotensive controls from a primary care setting. Twenty-four-hour ABP was measured with an automatic oscillometric device and recorded every 30 min throughout the day and night. Extreme dipper, dipper, non-dipper and reverse-dipper patterns were defined as those individuals with > 20%, 10-20%, < 10% and no fall in nocturnal ABP relative to daytime values. RESULTS: There were significant differences in ABP dipper status between cases and controls (cases - 16.15%, 60.00%, 17.70% and 6.15% vs controls - 3.19%, 31.9 2%, 42.02% and 22.88% for reverse dipper, non-dipper, dipper and extreme dipper, respectively, df = 3, χ(2) = 56.76, p < 0.001). Compared with normal controls, AD patients had significantly higher 24-h mean blood pressure, 24-h mean systolic blood pressure (SBP), night mean SBP, night mean pulse pressure (PP) and 24-h mean PP. There were no significant differences in 24-h mean diastolic blood pressure (DBP), daytime mean DBP or night-time mean DBP, and no significant differences in daytime mean SBP. CONCLUSIONS: The circadian rhythm of ABP in AD patents differed from normal controls, perhaps from higher night SBP in AD patents.

Age and risk for depression among the elderly: a meta-analysis of the published literature.

OBJECTIVE: The goal of this study was to determine the relationship between age and risk for depression among the old and the oldest old. Method MEDLINE, EMBASE, and the Cochrane Library database were used to identify potential studies. The studies were divided into cross-sectional and longitudinal subsets. For each study, the numbers of the total participants, cases (for cross-sectional study), or incident cases (for longitudinal study) of depression in each age group were extracted and entered into Review Manager 4.2 software. Qualitative meta-analyses of cross-sectional studies and of longitudinal studies were performed. For prevalence and incidence rates of depression, odds risk (OR) and relative risk (RR) were calculated, respectively. RESULTS: The qualitative meta-analyses showed that, compared with younger participants (above vs. below 65 years, above vs. below 70 years, above vs. below 75 years, and above vs. below 80 years), older age groups had a significantly higher risk for depression. (All of the ORs and RRs were significant.) Compared with participants aged 55-89, those aged above 90 years had no higher risk for depression. (Neither the OR nor the RR was significant.) CONCLUSIONS: Despite the methodological limitations of this meta-analysis, older age appears to be an important risk factor for depression in the general elderly population (aged below 80 years), but not in the oldest population (aged above 85 years).

Cognitive function and risk for depression in old age: a meta-analysis of published literature.

BACKGROUND: We assessed the relationship between cognitive impairment (including mild cognitive impairment with no signs of dementia, and dementia) and risk for depression in old age (60 years and older). METHODS: MEDLINE, EMBASE and the Cochrane Library database were used to identify potential studies. All of the clinical studies that produced data on the association between cognitive function and risk of depression among individuals aged 55 years or older were identified and included in this review. The studies were classified into cross-sectional and longitudinal subsets. The quantitative meta-analysis of cross-sectional and longitudinal studies were performed. For prevalence and incidence rates of depression, odds risk (OR) and relative risk (RR) were calculated, respectively. RESULTS: Since all but two studies found in the search were for individuals aged 60 years or over, we assessed and reported on results for this larger group only. In this review we included 13 cross-sectional and four prospective longitudinal studies. The quantitative meta-analysis showed that, in old age, individuals with non-dementia cognitive impairment had neither significant higher prevalence nor incidence rates of depression than those without (odds risk (OR): 1.48, 95% confidence intervals (95% CI): 0.87-2.52; relative risk (RR): 1.12, 95% CI: 0.62-2.01). In old age, individuals with dementia had both significant higher prevalence and incidence rates of depression than those without (OR: 1.82, 95% CI: 1.15-2.89; RR: 3.92, 95% CI: 1.93-7.99). CONCLUSIONS: Despite the methodological limitations of this meta-analysis, we found that in old age, there was no association between depression and cognitive impairment with no dementia; however, there was a definite association between depression and dementia and thus dementia might be a risk for depression.

Broilers' head behavior as an early warning index of production and lung health under ammonia exposure.

This study investigated the effects of ammonia exposure (0, 15, 25, and 35 ppm) on head behavior, production performance and lung tissue morphology of broilers, and the relationship between head behavior, production performance, and lung tissue injury. In this experiment, a total of 264 AA commercial male broilers (21 d old) were assigned to 4 treatment groups with 6 replicates of 11 chickens for a 21-day trial period, the frequency of head-scratching and head-shaking behavior at the initial stage (2, 24, and 72 h) of ammonia exposure were recorded, and the production performance indices and the lung pathological changes after 21 d of ammonia exposure were observed. The correlation analysis was established between head behavior and production performance indices. Results showed that head-scratching behavior increased under 15 ppm ammonia for 72 h, head-shaking behavior increased when exposure to 15 ppm ammonia for 2, 24, and 72 h, and lung tissue was injured when exposure to 15 ppm ammonia for 21 d. However, exposure to 15 ppm ammonia did not influence growth performance. Compared with the control group, exposure to 25 ppm decreased the ADG and exposure to 35 ppm decreased the ADG, ADFI, and F/G. Furthermore, the increase in head-shaking frequency after 2 h and 24 h ammonia exposure was significantly associated with production performance and lung tissue injury after 21 d ammonia exposure. In conclusion, the head-shaking behavior at the initial stage of ammonia exposure can reflect the degree of harm of the later production performance and lung tissue health.

Effects of ammonia exposure on growth performance and cytokines in the serum, trachea, and ileum of broilers.

This study investigated the effects of ammonia (NH3) exposure (0, 15, 25, and 35 ppm) on growth performance and cytokines in the serum, trachea, and ileum of broilers. A total of 288 22-day-old male broiler chickens were assigned to 4 treatment groups with 6 replicates of 12 chickens for a 21-D trial period. Growth performance and cytokines (IL-1ß, IL-6, and IL-10) concentrations in the serum, trachea, and ileum were measured in response to 3, 7, 14, or 21 D of exposure to NH3. Correlations between cytokines in the serum, trachea, and ileum and growth performance, and between tracheal and ileal cytokines, were also analyzed. Results showed that exposure to 15 ppm NH3 did not influence the growth performance, but exposure to both 25 ppm and 35 ppm NH3 decreased the growth performance compared to that of the control group. Exposure to 15 ppm NH3 for 3 D increased IL-6 concentrations and induced an inflammatory response in the trachea and ileum, whereas exposure to 15 ppm NH3 for 7 D increased IL-10 concentrations and induced an anti-inflammatory response in the ileum. Exposure to 25 ppm NH3 induced an inflammatory response in the serum, trachea, and ileum after 3 D and induced an anti-inflammatory response in the ileum after 7 D. Exposure to 35 ppm NH3 for 3 D induced both inflammatory and anti-inflammatory responses in the trachea and ileum. Furthermore, increases in cytokines in the serum, trachea, or ileum were accompanied by a decrease in BW, ADFI, ADG, and an increase of feed/gain (F/G) from 7 D to 21 D. In addition, tracheal cytokine, especially IL-1ß, was positively correlated with ileal cytokine IL-1ß. These results indicated that the low growth performance associated with NH3 exposure may be due in part to an increase in cytokines, and the inflammatory response in the trachea and ileum may be related to cross-talk by cytokines such as IL-6, IL-10, and, in particular, IL-1ß.

Ammonia induce lung tissue injury in broilers by activating NLRP3 inflammasome via Escherichia/Shigella.

Respiratory tract diseases are closely related to atmosphere pollution. Ammonia is one of the harmful pollutants in the atmosphere environment, which has a great threat to human and animal respiratory tract health, but the mechanism of causing diseases is not clear. In this study, broiler lung tissue was used as a model to study the effect of high ammonia on respiratory tract diseases through the relationship between respiratory microflora, NLRP3 inflammasome, and inflammatory factors. For this, we validated the occurrence of lung tissue inflammation under ammonia exposure and detected the lung tissue microbial constituent by 16S rDNA sequencing. Moreover, the relative expression levels of NLRP3 and caspase-1 mRNA and the content of IL-1ß and IL-6 were measured. After 7-D ammonia exposure, the proportion of the phylum Proteobacteria and the genus Escherichia/Shigella in lung tissue was significantly increased, the expression levels of NLRP3 and caspase-1 mRNA were significantly increased, and the content of IL-1ß in lung tissue and serum was higher than that in the control group. In conclusion, high ammonia induced lung tissue inflammation via increasing the proportion of Escherichia/Shigella, activating NLRP3 inflammasome, and promoting IL-1ß release. These findings provided a reference for the prevention and control of respiratory tract diseases in humans and animals caused by ammonia pollution.

Association of cognitive impairment with smoking, alcohol consumption, tea consumption, and exercise among Chinese nonagenarians/centenarians.

PURPOSE: In the present study, we observed the association of cognitive impairment with current/former habits of smoking, alcohol consumption, tea consumption, and exercise among very old people using a Chinese cohort aged 90 to 108 years. METHODS: A cross-sectional study. RESULTS: The sample included 681 unrelated Chinese nonagenarians/centenarians (67.25% women). In men, compared with subjects without cognitive impairment, those with cognitive impairment had significantly higher prevalence of habits of smoking (P=0.048 and 0.004, for former/current, respectively) and alcohol consumption (P=0.003 and 0.049, for former/current, respectively) but had significantly lower prevalence of habits of tea consumption (P=0.041 and 0.044, for former/current, respectively) and current exercise (P=0.020). Subjects with habits of smoking had significantly lower cognitive function scores than those without these habits (mean difference=1.78 and 1.69, P=0.029 and 0.035, for former/current, respectively), but subjects with habit of current exercise had significantly higher cognitive function scores than those without this habit (mean difference=1.53, P=0.038). However, in women, there were no significant differences in prevalence of these habits between subjects with and without cognitive impairment and also no significant differences in cognitive function scores between subjects with and without these habits. Only current smoking habits in men had a significant odds ratio for cognitive impairment (odds ratio, 2.125; 95% confidence interval, 1.186-3.998). CONCLUSIONS: Among nonagenarians/centenarians, in men, there are associations of cognitive impairment with habits of former/current smoking and current exercise, as well as indefinite associations with habits of alcohol and tea consumption. Smoking may have a significant negative impact on cognitive function, but current exercise significantly improve cognitive function. However, in women, there are no associations of cognitive impairment with all the habits.

Effects of stocking density on growth performance, growth regulatory factors, and endocrine hormones in broilers under appropriate environments.

Stocking density is an important environment factor that affects the development of poultry farming, which has caused widespread concern. This study was carried out to determine the effects of stocking density on growth performance, growth regulatory factors, and endocrine hormones in broilers under appropriate environments. A total of 144 Arbor Acres male broilers (BW 1000 ± 70 g) were randomly divided into low stocking density (LSD; 6.25 birds/m2), medium stocking density (MSD; 12.50 birds/m2), and high stocking density (HSD; 18.75 birds/m2) groups, with 6 replicates in each group, and raised in 3 environmental chambers (same size) from 29-day-old to 42-day-old, respectively. The trial period lasted for 14 D with 21 ± 1°C and 60 ± 7% relative humidity, wind speed < 0.5 m/s, ammonia level<5 ppm. The results indicated that average daily food intake and average daily gain in HSD group showed significantly lower than other 2 groups (P < 0.05). Besides, the HSD group significantly reduced breast muscle yield, tibial length, tibial width, and tibial weight of broilers (P < 0.05). The HSD group increased the mRNA expression level of myostatin, and reduced the mRNA expression levels of insulin-like growth factor 1 (IGF-1) and myogenic determination factor 1 (P < 0.05). The HSD group significantly reduced the expression of parathyroid hormone-related protein in tibial growth plate (P < 0.05). The HSD group increased the serum corticosterone levels of broilers (P < 0.05), and decreased the serum IGF-1 and thyroxine (T4) levels of broiler chickens (P < 0.05) than other stocking density groups. Moreover, the serum alkaline phosphatase levels were decreased (P < 0.05) with increasing stocking density, whereas there were no significant effects on the serum 3,5,3'-triiodothyronine (T3) concentrations in 3 groups (P > 0.05). In conclusion, under appropriate environments HSD reduced the growth performance of broilers and this negative effect was likely associated with decreased growth of muscle and bone.

[Study on the change of myocardial cell and matrix in the rats with insulin resistance and type 2 diabetes mellitus].

OBJECTIVE: To explore the injury of insulin resistance on cardiac muscle cell and matrix, and the relationship between insulin resistance and diabetic cardiomyopathy. METHODS: Twenty four Wistar rats of 6 months were randomly divided into normal control (N), insulin resistance group (I), diabetic group (D). Euglycemic insulin clamp technique (EICT) was used to determine insulin resistance (IR). Cadiocyte apoptosis was evaluated by TUNEL. Heart weight (HW) and body weight (BW) were measured to calculate HW/BW. Ultra-microstructure of cardiac muscle cell and structure of heart was observed. Masson dyeing, hydroxyproline detection and immunohistochemistry were used to measure the levels of collagen protein. RESULTS: Compared with controls, GIR decreased remarkably in D group and I group (P < 0.01). The number of apoptosis cell in I group was lower than that of D group (P < 0.01), and higher than that of N group (P < 0.01). Injury change of ultramicrostructure of myocardial cell was observed in the rats with type 2 diabetes mellitus or insulin resistance. Interstitial fibrosis of heart occurred in D group and I group. Content of Hydroxyproline, the level of I , III type of collagen, and the total level of collagen in I group were lower than those in D group, and higher than those in N group (P < 0.05). CONCLUSION: Insulin resistance in the rats with type 2 diabetes mellitus or insulin resistance can injury myocardial cell and matrix.

A proteomic approach reveals the differential protein expression in Drosophila melanogaster treated with red ginseng extract (Panax ginseng).

BACKGROUND: Red ginseng is a popularly used traditional medicine with antiaging effects in Asian countries. The present study aimed to explore the changes in protein expression underlying the mechanisms of life span extension and antiaging caused by red ginseng extract (RGE) in Drosophila melanogaster. METHODS: A proteomic approach of two-dimensional polyacrylamide gel electrophoresis (2-DE) was used to identify the differential abundance of possible target proteins of RGE in D. melanogaster. The reliability of the 2-DE results was confirmed via Western blotting to measure the expression levels of selected proteins. Proteins altered at the expression level after RGE treatment (1 mg/mL) were identified by matrix-assisted laser desorption/ionization-time of flight tandem mass spectrometry and by searching against the National Center for Biotechnology nonredundant and Uniprot protein databases. The differentially expressed proteins were analyzed using bioinformatics methods. RESULTS: The average survival life span of D. melanogaster was significantly extended by 12.60% with RGE treatment (1 mg/mL) compared to untreated flies. This followed increased superoxide dismutase level and decreased methane dicarboxylic aldehyde content. Based on the searching strategy, 23 differentially expressed proteins were identified (16 up-regulated and 7 down-regulated) in the RGE-treated D. melanogaster. Transduction pathways were identified using the Kyoto Encyclopedia of Genes and Genomes database, and included the hippo and oxidative phosphorylation pathways that play important roles in life span extension and antiaging process of D. melanogaster. CONCLUSION: Treatment with RGE in D. melanogaster demonstrated that mechanisms of life span extension and antiaging are regulated by multiple factors and complicated signal pathways.

The polymorphism of CLOCK gene 3111T/C C>T is associated with susceptibility of Alzheimer disease in Chinese population.

OBJECTIVES: In the present study, it was examined whether polymorphism of circadian locomotor output cycle kaput (CLOCK) gene 3111T/C was associated with susceptibility of Alzheimer disease (AD). METHODS: This study was conducted using a case-control method. Genotypes of apolipoprotein E (APOE e4) and CLOCK gene 3111T/C were determined by restriction fragment length polymorphism method and TaqMan assay method, respectively. RESULTS: In this study, we gathered 296 unrelated AD patients and 423 control subjects. Both in the whole sample and APOE e4 noncarriers, prevalence of C carriers in CLOCK gene 3111T/C in AD patients was significantly higher than that in control subjects (in the whole sample: χ = 37.615, P < 0.0001; in APOE e4 noncarriers: χ = 46.809, P < 0.0001). However, among APOE e4 carriers, prevalence of C carriers in CLOCK gene 3111T/C between patients and control subjects presents nonsignificant difference (χ = 0.812, P = 0.451). CONCLUSIONS: Among APOE e4 noncarriers, C carriers in CLOCK gene 3111T/C were associated with a high susceptibility of AD, but among APOE e4 carriers, the functional polymorphism of CLOCK gene 3111T/C was not associated with the susceptibility of AD.

No association between hypertension and risk for Alzheimer's disease: a meta-analysis of longitudinal studies.

This study examined the association between hypertension and AD by using a quantitative meta-analysis of longitudinal studies. EMBASE and MEDLINE were searched for articles published up to February 2011. All studies that examined the association of hypertension or antihypertensive medication use with the onset of AD were included. Pooled relative risks (RR) were calculated using fixed and random effects models. Twelve studies met our inclusion criteria for this meta-analysis. All subjects were without dementia at baseline. Among them, 9 studies compared the incidence of AD between subjects with (7,270) and without (8,022) hypertension. The quantitative meta-analysis showed that there was no significant difference in incidence of AD (RR: 1.02, 95% confidence interval (CI): 0.91-1.14) between subjects with and without hypertension. Seven studies compared the incidence of AD between subjects with (8,703) and without (13,041) antihypertensive medication use. The quantitative meta-analysis showed that there was no significant difference in incidence of AD (RR: 0.90, 95% CI: 0.79-1.03) between subjects with and without antihypertensive medication use. The quantitative meta-analysis showed that neither hypertension nor antihypertensive medication use was associated with risk for incident AD.

Chronic diseases and risk for depression in old age: a meta-analysis of published literature.

OBJECTIVE: We assessed the relationship between chronic diseases and risk for depression in old age. METHOD: MEDLINE, EMBASE, The Cochrane Library database were used to identify potential studies. All of the clinical studies that obtained data on the association between chronic diseases and risk of depression among individuals aged 55 years or older were identified and included in this review. The studies were classified into cross-sectional and longitudinal subsets. The quantitative meta-analysis of cross-sectional studies and that of longitudinal studies were preformed, respectively. For prevalence and incidence rates of depression, odds risk (OR) and relative risk (RR) were calculated, respectively. RESULTS: Since all but one study found in the search was for individuals 60 years of age or over, we assessed and report on results for this larger group only. 24 cross-sectional and 7 prospective longitudinal studies were included in this review. The quantitative meta-analysis showed that, among chronic diseases, stroke, loss of hearing, loss of vision, cardiac disease or chronic lung disease had both a significant OR and RR for increased depression in old age; arthritis, hypertension or diabetes had a significant OR but an un-significant RR for increased depression in old age; and gastrointestinal disease had neither a significant OR nor a significant RR for increased depression in old age. CONCLUSIONS: We concluded here that in old age, the associations of depression with some chronic diseases were definite; among these chronic diseases, stroke, loss of hearing, loss of vision, cardiac disease and chronic lung disease were risk factors for increased depression, but it should be further investigated whether arthritis, hypertension and diabetes were risk factors for increased depression or not.

Cognitive impairment and hypertension among Chinese nonagenarians and centenarians.

In this study, we explore the association between hypertension and cognitive impairment in the very elderly, using a sample ranging in age from 90 to 108 years. This work was conducted as a cross-sectional study. Our population included 782 unrelated Chinese nonagenarians and centenarians (67.5% women, mean age 93.62 years). The mean cognitive function score for the sample was 14.95 (s.d.: 5.99, range: 0-28). There were no significant differences between individuals with and without hypertension with regard to cognitive function scores (14.95+/-6.01 vs. 14.95+/-5.82, P=0.997) or cognitive impairment prevalence (59.52 vs. 59.42, P=0.976). There were also no significant differences in the prevalence of hypertension (56.99 vs. 57.10, P=0.976) or in the levels of arterial blood pressure (including systolic blood pressure (SBP) and diastolic blood pressure (DBP)) (139.86+/-22.69 vs. 140.28+/-23.51, P=0.799 and 73.05+/-12.07 vs. 72.11+/-12.06, P=0.678, for SBP and DBP, respectively) between individuals with and without cognitive impairment. Multiple logistic regression showed that cognitive impairment and hypertension were not risk factors for each other (odds ratio (OR) of cognitive impairment as a function of increased hypertension: 0.938 (0.655, 1.341); OR of hypertension as a function of increased cognitive impairment: 0.920 (0.643, 1.317)). In summary, we found that cognitive impairment was not directly correlated with hypertension among Chinese nonagenarians and centenarians.