Microbial community responses reduce soil carbon loss in Tibetan alpine grasslands under short-term warming

Changes in labile carbon (LC) pools and microbial communities are the primary factors controlling soil heterotrophic respiration (R_h ) in warming experiments. Warming is expected to initially increase R_h but studies show this increase may not be continuous or sustained. Specifically, LC and soil microbiome have been shown to contribute to the effect of extended warming on R_h . However, their relative contribution is unclear and this gap in knowledge causes considerable uncertainty in the prediction of carbon cycle feedbacks to climate change. In this study, we used a two-step incubation approach to reveal the relative contribution of LC limitation and soil microbial community responses in attenuating the effect that extended warming has on R_h . Soil samples from three Tibetan ecosystems-an alpine meadow (AM), alpine steppe (AS), and desert steppe (DS)-were exposed to a temperature gradient of 5-25°C. After an initial incubation period, soils were processed in one of two methods: (a) soils were sterilized then inoculated with parent soil microbes to assess the LC limitation effects, while controlling for microbial community responses; or (b) soil microbes from the incubations were used to inoculate sterilized parent soils to assess the microbial community effects, while controlling for LC limitation. We found both LC limitation and microbial community responses led to significant declines in R_h by 37% and 30%, respectively, but their relative contributions were ecosystem specific. LC limitation alone caused a greater R_h decrease for DS soils than AMs or ASs. Our study demonstrates that soil carbon loss due to R_h in Tibetan alpine soils-especially in copiotrophic soils-will be weakened by microbial community responses under short-term warming.

P14.33 Adult brainstem gliomas in neurofibromatosis type 1 (NF1)

BACKGROUND

The brainstem is the second location of brain tumors after optic pathways in NF1. In NF1 children, brainstem gliomas are usually indolent and have a better prognosis than their counterparts in non NF1 children. In contrast, the natural history and prognosis of adult brainstem gliomas in NF1 are nearly unknown.

MATERIAL AND METHODS

We conducted a retrospective analysis of medical records and MRI of adult NF1 patients followed for a brainstem glioma in 8 centers over a 17 years period (2000–2017). Clinical and imaging characteristics, management and outcome were analyzed.

RESULTS

Twenty five patients were included in the study (13 males and 12 females) with a median age of 32 (range 17–58). The epicenter of the tumor was located into the pons n=13 (52%), the mesencephalon n=7 (28%), the medulla oblongata n=5 (20%). On MRI, contrast enhancement was seen in 19 tumors (76%). Pathological examination was available in 13 tumors (52%) and showed a high grade astrocytoma (III or IV) in 9 tumors. Five patients were asymptomatic, 3 remained asymptomatic during the follow-up (median follow-up: 86 months, range 22–124). Twenty patients were symptomatic with a median duration of symptom of 2.5 months (range 1–10) before diagnosis. Among these symptomatic patients, 15 died from tumor progression despite treatment with radiation therapy and or chemotherapy. The median overall survival of symptomatic patients was 36 months.

CONCLUSION

Brainstem gliomas are rare tumors in adults with NF1. Unlike children, adult brainstem gliomas seem to have an unexpected poor prognosis, suggesting the disease may be different in adulthood.

Discoidin domain receptor 1 interactions with myosin motors contribute to collagen remodeling and tissue fibrosis

Discoidin Domain Receptor (DDR) genes and their homologues have been identified in sponges, worms and flies. These genes code for proteins that are implicated in cell adhesion to matrix proteins. DDRs are now recognized as playing central regulatory roles in several high prevalence human diseases, including invasive cancers, atherosclerosis, and organ fibrosis. While the mechanisms by which DDRs contribute to these diseases are just now being delineated, one of the common themes involves cell adhesion to collagen and the assembly and organization of collagen fibers in the extracellular matrix. In mammals, the multi-functional roles of DDRs in promoting cell adhesion to collagen fibers and in mediating collagen-dependent signaling, suggest that DDRs contribute to multiple pathways of extracellular matrix remodeling, which are centrally important processes in health and disease. In this review we consider that interactions of the cytoplasmic domains of DDR1 with cytoskeletal motor proteins may contribute to matrix remodeling by promoting collagen fiber alignment and compaction. Poorly controlled collagen remodeling with excessive compaction of matrix proteins is a hallmark of fibrotic lesions in many organs and tissues that are affected by infectious, traumatic or chemical-mediated injury. An improved understanding of the mechanisms by which DDRs mediate collagen remodeling and collagen-dependent signaling could suggest new drug targets for treatment of fibrotic diseases.

Relationship Between Bone Mineral Density T-Score and Nonvertebral Fracture Risk Over 10 Years of Denosumab Treatment

Although treat-to-target strategies are being discussed in osteoporosis, there is little evidence of what the target should be to reduce fracture risk maximally. We investigated the relationship between total hip BMD T-score and the incidence of nonvertebral fracture in women who received up to 10 years of continued denosumab therapy in the FREEDOM (3 years) study and its long-term Extension (up to 7 years) study. We report the percentages of women who achieved a range of T-scores at the total hip or femoral neck over 10 years of denosumab treatment (1343 women completed 10 years of treatment). The incidence of nonvertebral fractures was lower with higher total hip T-score. This relationship plateaued at a T-score between -2.0 and -1.5 and was independent of age and prevalent vertebral fractures, similar to observations in treatment-naïve subjects. Reaching a specific T-score during denosumab treatment was dependent on the baseline T-score, with higher T-scores at baseline more likely to result in higher T-scores at each time point during the study. Our findings highlight the importance of follow-up BMD measurements in patients receiving denosumab therapy because BMD remains a robust indicator of fracture risk. These data support the notion of a specific T-score threshold as a practical target for therapy in osteoporosis. © 2019 The Authors Journal of Bone and Mineral Research published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research (ASBMR).

Association between non-high-density lipoprotein cholesterol levels and asymptomatic vulnerable carotid atherosclerotic plaques

BACKGROUND AND PURPOSE

Carotid atherosclerosis, especially rupture of plaques, is related to cerebrovascular diseases. Non-high-density lipoprotein cholesterol (non-HDL-C) is relevant to cerebrovascular diseases and may be a potential risk factor. We designed this study to investigate the association between non-HDL-C and the prevalence of asymptomatic vulnerable carotid atherosclerotic plaques.

METHODS

We enrolled 2888 participants who underwent carotid atherosclerotic plaque detection and non-HDL-C measurement, with no history of taking lipid-lowering agents, from the Asymptomatic Polyvascular Abnormalities in Community study. We used multivariable logistic regression to estimate the association between non-HDL-C levels and the presence of asymptomatic vulnerable carotid atherosclerotic plaques.

RESULTS

In our study, 1505 subjects had asymptomatic vulnerable carotid atherosclerotic plaques and 1383 subjects had stable plaques. After adjustment for confounding factors, the odds ratios for vulnerable plaques of non-HDL-C levels in the middle and highest tertile groups were 1.02 (95% confidence interval, 0.84-1.23) and 1.50 (95% confidence interval, 1.23-1.82), respectively (P trend < 0.01).

CONCLUSION

In our community-based observational and cross-sectional study, non-HDL-C level was a significant risk factor for the occurrence of asymptomatic vulnerable carotid plaques.

Feed preference and feeding behaviours in grower broilers fed diets containing wheat naturally contaminated with fusarium mycotoxins

1. Two trials were conducted to determine the effect of feeding diets contaminated with fusarium mycotoxins (primarily deoxynivalenol (DON)) on broiler chicken feed preference, feeding behaviour and growth performance. 2. A total of 120 male Ross 308 chicks (4 birds/cage, 30 cages) were fed a common corn-based starter diet from 1 to 20 d of age. At 21 d, 15 cages were randomly assigned to the feed preference trial or a feeding behaviour trial. Three wheat-based experimental diets (0.14, 2.27 and 5.84 mg/kg DON) were prepared with a clean wheat and a naturally contaminated wheat. Broilers were ad libitum fed the experimental diets during 21-27 d. 3. In the preference trial, each cage's feeder was split into two equal-sized compartments so birds were provided a choice of two diets (control vs. low, control vs. high and low vs. high DON). In the feeding behaviour trial, diets were randomly assigned to 15 cages (5 cages/diet). Feeding and drinking behaviour was recorded for 1 h before and after the dark period and 1-h period at 9 h after the light was turned on (middle of day). Growth performance was assessed at 27 d. 4. In the preference trial, broilers preferred the control diet over low (93.0 vs. 66.1 g/d, P < 0.01) and high (104.4 vs. 50.4 g/d, P < 0.01) DON diets. At all three timepoints, where behaviour was recorded, birds offered the DON diets spent more time at the feeder compared to birds provided control diets (P < 0.05). Control birds had lower feed to gain ratio (1.65) than birds fed low (1.82) and high (1.94) DON diets (P < 0.01). 5. It is clear that broilers are sensitive to the presence of fusarium mycotoxins and that moderate levels of DON negatively affect feed preference and growth performance when fed during the grower period.

Oxidative lipoprotein markers predict poor functional outcome in patients with minor stroke or transient ischaemic attack

BACKGROUND AND PURPOSE

Oxidative stress plays an important role in acute ischaemic stroke. However, the association of oxidative lipoprotein markers, including oxidized low-density lipoprotein (oxLDL), oxLDL:high-density lipoprotein (HDL) and oxLDL:low-density lipoprotein (LDL), with functional outcome of minor stroke or transient ischaemic attack (TIA) remains unclear. We aimed to investigate the association between oxidative lipoprotein markers and poor functional outcome in patients with minor stroke or TIA.

METHODS

All patients with minor stroke or TIA were recruited from the Clopidogrel in High-Risk Patients With Acute Non-Disabling Cerebrovascular Events (CHANCE) trial. The poor functional outcome included modified Rankin Scale (mRS) score 2-6 and 3-6 at 90-day and 12-month follow-up. Multivariate logistic regression was used to investigate the associations of oxLDL, oxLDL:HDL and oxLDL:LDL with poor functional outcome.

RESULTS

Among 3019 patients included in this study, the median (interquartile range) oxLDL, oxLDL:HDL and oxLDL:LDL were 13.96 (6.65-28.81), 4.52 (2.08-9.32) and 11.73 (5.27-24.85) μg/dL, respectively. After adjusted for confounding factors, patients in the highest oxLDL quartile had a higher proportion of mRS score 2-6 at 90 days [hazard ratio (HR), 1.78; 95% confidence interval (CI), 1.26-2.52] and 12 months (HR, 1.42; 95% CI, 1.01-1.99), and mRS score 3-6 at 90 days (HR, 1.98; 95% CI, 1.29-3.04) and 12 months (HR, 1.77; 95% CI, 1.09-2.89) when compared with the lowest oxLDL quartile (P < 0.05). Similar results were found for oxLDL:HDL and oxLDL:LDL.

CONCLUSIONS

Higher levels of oxidative lipoprotein markers are independent predictors of poor functional outcome in patients with minor stroke or TIA at 90 days and 12 months.