[Mediating effect of unhealthy lifestyle and depressive symptom on association between life course factors and ageing health]

Objective: To explore the mediating effect of unhealthy lifestyle and depressive symptom on the associations between life course factors and aging health. Methods: The study included 6 217 participants (aged ≥45 years) from the China Health and Retirement Longitudinal Study (CHARLS). We used principal component analysis (PCA) and hierarchical clustering analysis (HCA) to divide participants into six subgroups based on 70 life course factors. Five key life course factors were identified based on correlation analysis and their contribution to aging health. Physiological dysregulation (PD) was calculated by using eight biomarkers in the 2015 CHARLS biomarker dataset. Linear regression, logistic regression, and mediation models were used to explore the complex associations of life course subgroups, key factors, unhealthy lifestyle, depression symptom with PD. Results: Life course subgroups were significantly associated with PD after adjusting chronological age and gender (β: 0.08-0.17, all P<0.05). Life-course subgroups and key factors, including adverse experiences in adulthood and lower education level, were significantly associated with unhealthy lifestyle (β: 0.04-0.52, all P<0.05). Life-course subgroups and key factors, including childhood trauma, parental health in childhood, adverse experiences in adulthood, and lower education level, were significantly associated with depression symptom (OR: 1.16-4.76, all P<0.05). Mediation analysis showed that unhealthy lifestyle had partial mediating effect on the association of life course subgroups and key factors, including adverse experiences in adulthood, and lower education levels, with PD (3.1%-3.6%). Depression symptom had partial mediating effect on the association of life course subgroups and key factors, including childhood trauma, adverse experience in adulthood, and lower education level, with PD (6.0%-16.2%). Conclusions: Unhealthy lifestyle and depression symptom has partial mediating effect on the impact of life course factors on aging health. It is important to pay attention to these two modifiable factors while targeting childhood trauma and adverse experience in adulthood.

Changes in astrocyte functional markers and β-amyloid metabolism-related proteins in the early stages of hypercholesterolemia

Cholesterol is an essential substance for maintaining normal structure and function of the brain. But unfortunately, a long-term high-cholesterol diet can lead to a variety of pathological changes of the brain such as β-amyloid (Aβ) accumulation, Tau hyperphosphorylation, reactive gliosis, neuroinflammation, neuronal death and synaptic degeneration. These pathological changes have complex internal relations with one other, causing memory impairment and participating in the pathogenesis of Alzheimer's disease (AD). However, early hypercholesterolemia-induced events that lead to brain deterioration are not clear. To address this, 6-month-old female mice were fed a 3% cholesterol diet for 8weeks, followed by behavioral, biochemical and neuropathological analyses. The high-cholesterol-fed mice did not show neuronal and synaptic impairment or cognitive deficits compared with mice given a normal diet, but astrocytes were mildly activated with increased expression of functional markers including apolipoprotein E and aquaporin 4 in the hippocampus. Hippocampal interleukin-1β expression slightly increased, but interleukin-6 (IL-6) and tumor necrosis factor-α did not change significantly compared with those in the control group. Levels of Aβ, and its precursor protein, were unaffected, but levels of presenilin 1 and insulin-degrading enzyme (IDE), that initiate Aβ generation and degradation, respectively, increased in the hippocampus of the model mice. In addition, Tau phosphorylation levels were not different between the control and model groups. These results suggest that changes in astrocyte functional markers and Aβ metabolism proteins, which contribute to maintaining brain cholesterol and Aβ homeostasis, are early events in the process of hypercholesterolemia-related neuropathological changes.

A normobaric gas exposure animal chamber and its validation in hyperoxia exposure

We are living in an environment full of gases, and any change in the concentration of a component of the air or contaminants (usually toxic) in the air may significantly threaten human health. Thus, to investigate the influence of gases in animal models it is helpful to elucidate the pathogenesis of gas-related injury. Although there are devices used for gas exposure in animals, there are still limitations in the establishment of these animal models, such as the change in gas concentration during the refreshing of water, food and litter, and the contamination of toxic gases released by animals. Herein, we freshly prepared a chamber for normobaric gas exposure. During the exposure in this chamber, the refreshing of water, food and litter does not require opening of the chamber. The chamber gases are continuously circulated and filtered, and the gas concentration remains very stable. To validate the feasibility of this chamber, rats were exposed to pure oxygen as an example. Results showed that rats with hyperoxia-induced lung injury simulated by pure oxygen exposure displayed the representative characteristics as observed in humans: shortness of breath, lung edema, alveolar septal rupture, infiltration of inflammatory cells, oxidative and inflammatory injury. This suggests that it is feasible to establish animal models using this chamber for the investigation of gas toxicity.

First Report of Alternaria alternata Causing Black Leaf Spot of Rubber Tree in China

We first reported Alternaria heveae (E.G. Simmons ) to be the pathogen that caused black leaf spot of rubber tree (Hevea brasiliensis Muell. Arg) in Heikou county in July 2014 (1). Black leaf spots that resembled the symptoms caused by A. heveae were observed on the leaves of rubber trees of the whole propagule collection nursery in Jingping County (22°68' N and 103°05' E) of Yunnan Province. Black foliar spots (0.1 to 2 mm in diameter) surrounded by a yellow halo with lesions slightly sunken on the leaf surface were observed. To confirm whether the disease was caused by the same pathogen, 5-mm² sections were removed from the leading edge of the lesion and were surface-sterilized in 75% ethanol, air-dried, plated on potato carrot agar (PCA), and incubated at 28°C in the dark. Colonies of the fungus on PCA had round margins and little aerial mycelia with gray-black coloration after 6 days of growth on PCA (2). Medium brown conidia were found to be in short chains of two to eight spores, ovoid, obclavate, and obpyriform, with or without a short conical or cylindrical-shaped apical beak. Conidia ranged from 22.5 to 67.5 μm long (mean 39.9 μm) × 10 to 15 μm wide (mean 12.5 μm; 100 colodia were measured), with three to six transverse septa and zero to three longitudinal or oblique septa. Morphological characteristics matched the descriptions of A. alternata [(Fries) Keissler] (4).The ITS1-5.8S-ITS2 region of one single-spore isolate, Ah02JP1, was amplified with primers ITS1 and ITS4. The PCR product was sequenced directly and deposited in GenBank (Accession No. KM111289). A BLAST search of the GenBank database revealed 100% similarity with A. alternata isolates KJ829535.1, KJ677246.1, and KF813070.1. Therefore, the pathogen was identified as A. alternata on the basis of its morphological characteristics and ITS sequence. Pathogenicity of a representative isolate, Ah02JP1 was confirmed using a field rubber tree inoculation method. Three rubber plants (the clone of rubber tree Yunyan77-4) were grown to the copper-colored leaf stage. Leaves were spray-inoculated (10⁴ conidia per milliliter spore suspension) until drops were equally distributed using a manual pressure sprayer. Three rubber plants sprayed with sterile distilled water were used as controls. After inoculation, the plants were covered with plastic bags to maintain high relative humidity. The plastic bags were removed 2 days post-inoculation (dpi), and the plants were monitored daily for symptom development. Five days post-inoculation, spots similar to the original ones seen on the field trees developed on all inoculated leaves, while control leaves remained symptomless. A. alternata was re-isolated from spray-inoculated leaves, confirming Koch's postulates. A. alternata has been reported as the causal agent of leaf blight of rubber tree in India, which initially appeared as minute spots on leaves and enlarged with the growth of the leaves (3). However, in the present study, the symptoms (black leaf spots) remained small over time after inoculation. To our knowledge, this is the first report of A. alternata on rubber tree in China. Correct identification of pathogens is essential for disease management strategies. This report will establish a foundation for the further study of Alternaria alternata to address the disease effectively. References: (1) Z. Y. Cai et al. Plant Dis. 98:1011, 2014. (2) E. Mirkova. J. Phytopathol. 151:323, 2003. (3) C. B. Roy et al. J. Plantation Crops 34:499, 2006. (4) T. Y. Zhang. Page 32 in: Flora Fungorum Sinicorum, Vol. 16: Alternaria. Science Press, Beijing, 2003.

Nanowire Modified Electrode for Sensitive Measurement of Nicotinic Acid

A simple and sensitive method has been developed to measure nicotinic acid using CuGeO 3 nanowire modified glassy carbon electrode (GCE). The CuGeO 3 nanowires can be attached firmly to the surface of the GCE. The modified GCE exhibits good detection performance for nicotinic acid with the correlation coefficient of 0.993 and 0.985 for cvp1 and cvp2, respectively. The detection limit is 9.2 μM and 0.83 μM, respectively at a signal-to-noise ratio of 3 with the linear range of 0.001–2 mM. The CuGeO 3 nanowire modified GCE exhibits good stability and reproducibility.

First Report of Alternaria heveae Causing Black Leaf Spot of Rubber Tree in China

Rubber tree (Hevea brasiliensis Muell. Arg.) is an important industrial crop of tropical areas for natural rubber production. In October 2013, foliar spots (0.1 to 0.4 mm in diameter), black surrounded by a yellow halo, and with lesions slightly sunken were observed on the rubber tree leaf in a growing area in Heikou County of Yunnan Province. Lesion tissues removed from the border between symptomatic and healthy tissue were surface sterilized in 75% ethanol and air-dried, plated on PDA plates, and incubated at 28°C with alternating day/night cycles of light. The pathogen was observed growing out of many of the leaf pieces, and produced abundant conidia. Colonies 6.1 cm in diameter developed on potato carrot agar (PCA) after 7 days, with well-defined concentric rings of growth. Colonies on PCA were composed of fine, dark, radiating, surface and subsurface hyphae. Conidia produced in PCA culture were mostly solitary or in short chains of 2 to 5 spores, long ovoid to clavate, and light brown, 40 to 81.25 × 8 to 20 μm (200 colonies were measured), with 3 to 6 transverse septa and 0 to 2 longitudinal or oblique septa. Morphological characteristics were similar to those described for Alternaria heveae (3,4). A disease of rubber tree caused by Alternaria sp. had been reported in Mexico in 1947 (2). DNA of Ah01HK13 isolate was extracted for PCR and sequencing of the ITS region with ITS1 and ITS4 primers was completed. From the BLAST analysis, the sequence of Ah01HK13 (GenBank Accession No. KF953884), had 97% similarity to A. dauci, 96% identical to A. macrospora (AY154701.1 and DQ156342.1, respectively), indicating the pathogen belonged to Alternaria genus. According to morphological characteristics, this pathogen was identified as A. heveae. Pathogenicity of representative isolate, Ah01HK13 was confirmed using a field rubber tree inoculation method. Three rubber plants (the clone of rubber tree Yunyan77-4) were grown to the copper-colored leaf stage and inoculated by spraying spore suspension (concentration = 10⁴ conidia/ml) to the copper-colored leaves until drops were equally distributed on it using manual pressure sprayer. Three rubber plants sprayed with sterile distilled water were used as controls. After inoculation, the plants were covered with plastic bags. The plastic bags were removed after 2 days post-inoculation (dpi) and monitored daily for symptom development (1). The experiment was repeated three times. The typical 0.1 to 0.4 mm black leaf spots were observed 7 dpi. No symptoms were observed on control plants. A fungus with the same colony and conidial morphology as A. heveae were re-isolated from leaf lesions on inoculated rubber plants, but not from asymptomatic leaves of control plants, fulfilling Koch's postulates. Based on these results, the disease was identified as black spot of rubber tree caused by A. heveae. To our knowledge, this is the first report of A. heveae on rubber tree in China. References: (1) Z. Y. Cai et al. Microbiol Res. 168:340, 2013. (2) W. J. Martin. Plant Dis. Rep. 31:155, 1947. (3) E. G. Simmons. Mycotaxon 50:262, 1994. (4) T. Y. Zhang. Page 111 in: Flora Fungorum Sinicorum: Alternaria, Science Press, Beijing, 2003.

Determination of Cyanuric Acid by Electrochemical Cyclic Voltammetry Method Using CuGeO3 Nanowires as Modified Electrode Materials

A simple electrochemical method for the determination of cyanuric acid (CA) has been developed based on a CuGeO3 nanowire modified glassy carbon electrode. The dense CuGeO3 nanowire film can be formed on the surface of the glassy carbon electrode. The roles of scan rate, CA concentration, and electrolytes with different pH values on the electrochemical responses of CA have also been analyzed. The intensities of two anodic peaks vary linearly with the increase of the scan rate from 25 to 200 mVs−1. The intensity of the electrochemical CV peak increases with the increase of the acidity of the electrolytes. The two anodic peak currents are linear with the CA concentration in the range of 0.005–2 mM. The linear correlation coefficient is 0.984 and 0.980 for the cyclic voltammogram peaks (cvp) cvp1 and cvp2, respectively. The detection limit is 4.3 μM and 2.1 μM for cvp1 and cvp2, respectively. The proposed electrochemical method is convenient and effective sensing of CA.

Comparison of methylation procedures for conjugated linoleic acid and artifact formation by commercial (trimethylsilyl) diazomethane

Four different methods for methylating conjugated linoleic acid (CLA) were compared. The HCl/MeOH and BF(3)/MeOH methods were tested under different time and temperature combinations. Increasing temperature and/or incubation time for either method decreased the cis-9,trans-11 and trans-10,cis-12 isomers, but trans-9,trans-11/trans-10,trans-12 isomers and artifacts (allylic methoxide) were increased. In addition, the triacylglyceride form of CLA was tested using the above methods and NaOMe at various temperatures for 20 min. The NaOMe did not generate methoxy artifacts. However, there were impurities in GC after methylation with NaOMe as well as with BF(3)/MeOH. The (trimethylsilyl)diazomethane method, which is a mild and easy alternative, was tested. Free forms of fatty acids were easily, but not completely, methylated by this method. Also, the method generated artifacts (trimethylsilyl CLA esters) and impurities (trimethylsilyl) that would interfere with short-chain fatty-acid analysis by GC.

Huperzine-A in capsules and tablets for treating patients with Alzheimer disease

AIM

To compare the efficacy and safety between huperzine-A (Hup) in capsules and tablets for treating patients with Alzheimer disease (AD).

METHODS

Using multicenter, prospective, double-blind, double-mimic, parallel, positive controlled and randomized methods, 60 patients meeting with the NINCDS-ARDRA criteria of AD were divided into 2 equal groups. Patients in the capsule group received 4 capsules of Hup (each contains 50 micrograms) and 4 tablets of placebo (lactose and starch inside); while the tablet group received 4 tablets of Hup (each contains 50 micrograms) and 4 capsules of placebo, p.o., twice a day for 60 d. All the patients were evaluated with a lot of related ranting scales, and physiological and laboratory examination.

RESULTS

There were significant differences (P < 0.01) on all the psychological evaluations between 'before' and 'after' the 60-d trial of 2 groups, but there was no significant difference between 2 groups by group t test (P > 0.05). The changes of oxygen free radicals in 2 groups showed marked improvement. No severe side effect besides moderate to mild nausea was found in both groups.

CONCLUSION

There is equal efficacy and safety between Hup in capsule and tablet for treating patients with AD, and Hup can reduce the pathological changes of the oxygen free radicals in the plasma and erythrocytes of patients with AD.