[Species composition and community structure of coniferous-broadleaved mixed forest in Xiaolong Mountain, Gansu Province, Northwest China]. / 甘肃小陇山暖温带针阔混交林物种组成和群落结构.

Xiaolong Mountain, located in warm temperate subtropical transition zone, is one of the important biodiversity conservation areas in China. We analyzed species composition, community structure, and habitat preferences of all woody plant species with DBH (diameter at breast height)≥1 cm in a 6 hm2 plot in Xiaolong Mountain, Gansu Province, Northwest China. A total of 29251 individuals (41735 stems) belonging to 33 families, 65 genera, and 124 species were recorded. The 28 species with importance value ≥1 contributed 82.9% to the total abundance. The top four species with the highest importance value were Quercus aliena var. acuteserrata, Betula platyphylla, Lindera aggregata var. playfairii and Corylus heterophylla. The structure of DBH size class of all stems showed an inverse 'J' type, indicating a successful regeneration tendency in the understory. Results from the indicator species analysis showed that 11 species had significant habitat prefe-rences, an two species (Ostrya japonica and Acer stachyophyllum subsp. betulifolium) had the most obvious preferences. Results from the redundancy analysis and partial methods showed that topographic factors played a dominant role in determining species distribution.

Serum Total Cholinesterase Activity on Admission Is Associated with Disease Severity and Outcome in Patients with Traumatic Brain Injury.

BACKGROUND: Traumatic brain injury (TBI) is one of the leading causes of neurological disability. In this retrospective study, serum total cholinesterase (ChE) activities were analyzed in 188 patients for diagnostic as well as predictive values for mortality. METHODS AND FINDINGS: Within 72 hours after injury, serum ChE activities including both acetylcholinesterase and butyrylcholinesterase were measured. Disease severity was evaluated with Acute Physiology and Chronic Health Evaluation (APACHE) II score, Glasgow Coma Score, length of coma, post-traumatic amnesia and injury feature. Neurocognitive and functional scores were assessed using clinical records. Of 188 patients, 146 (77.7%) survived and 42 (22.3%) died within 90 days. Lower ChE activities were noted in the non-survivors vs. survivors (5.94±2.19 vs. 7.04±2.16 kU/L, p=0.023), in septic vs. non-infected patients (5.93±1.89 vs. 7.31±2.45 kU/L, p=0.0005) and in patients with extremely severe injury vs. mild injury (6.3±1.98 vs. 7.57±2.48 kU/L, p=0.049). The trajectories of serum ChE levels were also different between non-survivors and survivors, septic and non-infected patients, mild and severely injured patients, respectively. Admission ChE activities were closely correlated with blood cell counts, neurocognitive and functional scores both on admission and at discharge. Receiver operating characteristic analysis showed that the area under the curve for ChE was inferior to that for either APACHE II or white blood cell (WBC) count. However, at the optimal cutoff value of 5 kU/L, the sensitivity of ChE for correct prediction of 90-day mortality was 65.5% and the specificity was 86.4%. Kaplan-Meier analysis showed that lower ChE activity (<5 kU/L) was more closely correlated with poor survival than higher ChE activity (>5 kU/L) (p=0.04). After adjusting for other variables, ChE was identified as a borderline independent predictor for mortality as analyzed by Binary logistic regression (P=0.078). CONCLUSIONS: Lowered ChE activity measured on admission appears to be associated with disease severity and outcome for TBI patients.

[Establishment of a Wistar rat model bearing brain glioma C6 cells and its experimental application].

OBJECTIVE: To establish a rat model bearing brain glioma and investigate the optimal conditions for its experimental application. METHODS: C6 cells were implanted into the unilateral brain hemisphere of 20 Wistar rats. The growth behaviors of the brain tumor and behavioral changes of the rats were observed at different time points after the implantation. RESULTS: On day 3 after the implantation, only a slight increase of signal intensity was observed on T2-weighted images. By day 5, the tumor became visible in 15/18 of the rats in at least two sections. By day 11, 16/18 of the rats showed space-occupying effect in the brain, and by day 14, the tumor occupied over 1/2 of the hemisphere in 14/18 of the rats. By day 20, 14/18 of the rats showed a tumor mass occupying over 2/3 of the hemisphere, and some tumor cells had migrated into the contralateral hemisphere. CONCLUSION: In this model of brain glioma, the optimal time widow for experiment is between 14 and 18 days after the cell implantation. The cell density and viability for implantation and the site of implantation may also affect the experimental time widow.

Localization and distribution of magnetic chemotherapeutic drugs with magnetic targeting in rat brain.

BACKGROUND: Magnetic targeting therapy may be a new method for the treatment of malignent tumors. The purpose of this study was to investigate the localization and distribution of ferrofluid microsphere of human serum albumin methotrexate (FM-HSA-MTX) carriers in the brain and to explore the magnetic targeting chemotherapy for malignant brain tumor. METHODS: Ninety SD rats were divided into three groups: targeting group, non-magnetic targeting group, and control group. Synthesized FM-HSA-MTX carriers (MTX 25 mg/kg) were injected into the systemic circulation via the caudal vein (magnetic targeting group, n = 30). A 0.6 T magnetic field was placed around the right hemisphere. The non-magnetic targeting group (n = 30) was administered with FM-HSA-MTX without external magnetic field, meanwhile the control group (n = 30) was treated with MTX and a magnetic field. Random serial sacrifices (n = 10) were conducted at 15, 30 and 45 minutes after drug administration. Bilateral hemispheres were collected respectively, and analyzed for total MTX content. RESULTS: MTX content in the right hemisphere of the magnetic targeting group was significantly higher than that in the other two groups at 15, 30 and 45 minutes after drug administration (P < 0.05) No difference was seen between the non-targeting group and control group. In the magnetic targeting group, MTX returned to the peak level [(0.564 +/- 0.018) mg/g, q15-45 = 32.252, P < 0.05] 45 minutes after the injection but it deceased in the other two groups [non-magnetic targeting group: (0.060 +/- 0.015) mg/g, q15-45 = 9.245, P < 0.05, control group: (0.074 +/- 0.045) mg/g, q15-45 = 6.299, P < 0.05]. In the magnetic targeting group, the concentration of MTX in the right hemisphere was significantly higher than that in the left hemisphere (t45min = 21.135, P = 0.000) but no difference was observed between bilateral hemispheres in the other two groups (non-magnetic targeting group: t45min = 0.434, P = 0.670; control group: t45min = 0.533, P = 0.600). CONCLUSION: In the presence of the external magnetic field, FM-HSA-MTX can distribute successfully in the targeting areas of the brain.