Search

The population structure characteristics, natural regeneration, and the influential factors of Haloxylon ammodendron plantations at six different stand ages on the southern edge of the Gurbantunggut Desert were studied. The results showed that H. ammodendron plantation at the stand age of 7 could naturally regenerate. At the stand age of 17, the densities of the seedlings (＜30 cm height), saplings (30≤H＜50 height), and small trees (≥50 cm height) reached optimal class, and the mean height and base diameter of the small tress reached 1.10 m and 1.91 cm, respectively. The parent trees in H. ammodendron plantation at the stand age of 20 grew best. The height of 35% individuals grew up to 2.50-3.00 m, and the basal stem diameter of 23.1% individuals grew up to 8.00-10.00 cm. The height and diameter growth of the parent trees in H. ammodendron plantation at the stand age of 33 apparently declined, but the regeneration ability by natural seed dispersal was still strong. The regeneration density of natural seed dispersal showed the greatest correlation with the available nitrogen content in 0-100 cm soil layer (0.87), followed by the soil rapidly available phosphorus content (0.84) and the soil water content (0.79). The soils with pH 8.1-8.6 did not limit the nutrient growth of the regeneration layer. In the main stand layer, the individual density of whole regeneration layer showed the greatest correlation with the biomass of the parent trees (0.77), while the density of regeneration layer of the small trees showed the greatest correlation with the planting density (0.71) and the age of the parent trees (0.70).

The mevalonate pathway has been extensively studied for its involvement in cholesterol synthesis. Inhibition of this pathway using statins (3-Hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors; HMGR inhibitors) is the primarily selected method due to its cholesterol-lowering effect, making statins the most commonly used (86-94%) cholesterol-lowering drugs in adults. This pathway has several other by-products that are affected by statins including GTPase molecules (guanine triphosphate-binding kinases), such as Rho/Rho-associated coiled kinase (ROCK) kinases, that are implicated in other diseases, including those of the central nervous system (CNS). These molecules control several aspects of neural cell life including axonal growth, cellular migration, and cell death, and therefore, are of increasing interest in the field of spinal cord injury (SCI). Limited regeneration capacity of nerve fibers in adult CNS has been considered the main obstacle for finding a SCI cure. Over the past two decades, the identity of inhibitory factors for regeneration has been widely investigated. It is well-established that the Rho/ROCK kinase system is specifically activated by the components of damaged spinal cord tissue, including oligodendrocytes and myelin, as well as extracellular matrix. This has led many groups to hypothesize that statin therapy may in fact enhance the current neurorestorative approaches. In this mini-review, a summary of SCI pathophysiology is discussed and the current literature targeting the regeneration obstacles in SCI are reviewed, with special attention to recent publications of the past decade. In addition, we focus on the current literature involving the use of pharmacological and molecular inhibitors of small GTPase molecules for treatment of neurotrauma. Inhibiting these molecules has been shown to increase neuroprotection, enhance axonal regeneration, and facilitate the implementation of cell replacement therapies. Based upon available literature, the need for clinical trials involving targeted inhibition of GTPase molecules remains strong. Some of these drugs are widely used for other diseases, and therefore re-purposing their application for neurotrauma can be fasttracked. These approaches can potentially modify the inhibitory environment of nervous tissue to allow the spontaneous repair capacity of injured tissue., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

The mevalonate cascade is a key metabolic pathway that regulates a variety of cellular functions and is thereby implicated in the pathophysiology of most brain diseases, including neurodevelopmental and neurodegenerative disorders. Emerging lines of evidence suggest that statins and Rho GTPase inhibitors are efficacious and have advantageous properties in treatment of different pathologic conditions that are relevant to the central nervous system. Beyond the original role of statins in lowering cholesterol synthesis, they have anti-inflammatory, antioxidant and modulatory effects on signaling pathways. Additionally, Rho GTPase inhibitors and statins share the mevalonate pathway as a common target of their therapeutic actions. In this review, we discuss potential mechanisms through which these drugs, via their role in the mevalonate pathway, exert their neuroprotective effects in neurodegenerative and neurodevelopmental disorders., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

Species composition and diameter class structure were investigated in 1.5 hm2 (100 m x 150 n) permanent plot in Picea koraiensis and Abies nephrolepis forest of Xiaoxing' an Mountains. The spatial distribution pattern and spatial association of main populations and gap makers were analyzed by using point pattern analysis. The results showed that there were a total of 13 species with diameters at breast height greater than 2 cm in tree layer, and great differences were observed in the densities of main populations. The importance values of A. nephrolepis, P. koraiensis, Betula platyphylla and Acer ukurunduense were ranked in the first 4 in the plot. The diameter class structure of their populations presented an inverse 'J' curve. The spatial distribution patterns for A. nephrolepis and P. koraiensis were similar, which changed from aggregated, random to uniform distribution with the spatial scale. For B. platyphylla, the distribution was aggregated at ≤40 m scale, and random at >40 m scale, whereas A. ukurunduense presented an aggregated distribution pattern at the whole research scale. Except that the negative correlation between B. platyphylla and A. ukurunduense existed at the whole research scale, positive correlation between the other populations at small scale and negative correlation at large scale were observed. Only A. nephrolepis and B. platyphylla had significant positive correlation, and generally no significant correlation existed between other populations. Spatial distribution pattern of gap makers was characterized as aggregated distribution at small and middle scales, and random distribution with increasing scale. Spatial point pattern of gap makers formed by uprooting exhibited unimodal type distribution, and random, aggregated, and uniform distribution also occurred. Spatial point pattern of gap makers formed by breaking overall presented a little fluctuation, random and aggregated distributions alternatively appeared at small scale, and random distribution happened at large scale. Their spatial correlation analysis indicated that significant positive correlation existed at ≤32 m scale, and non-significant negative correlation at >32 m scale.

Aim: To summarize our single-center experience with liver transplantation (LT) for biliary atresia (BA)., Methods: From October 2006 to December 2012, 188 children with BA were analyzed retrospectively. The stage I group (from October 2006 to December 2010) comprised the first 74 patients, and the stage II group (from January 2011 to December 2012) comprised the remaining 114 patients. Finally, 123 liver transplants were performed in 122 (64.9%) patients, whereas 66 patients did not undergo LT due to denial by their parents or lack of suitable liver grafts. The selection of graft types depended on the patients' clinical status and whether a suitable living donor was available. The characteristics of patients in stages I and II were described, and the surgical outcomes of LT recipients were compared between the two stages. The Kaplan-Meier method was used to estimate the cumulative patient and graft survival rates, and the equality of survival distributions was evaluated using the log-rank test., Results: The 188 children consisted of 102 boys and 86 girls. Their ages ranged from 3 to 144 mo with a median of 8 mo. One hundred and fifteen (61.2%) patients were born in rural areas. Comparing stage I and stage II patients, the proportion of patients referred by pediatricians (43.2% vs 71.1%, respectively; P < 0.001) and the proportion of patients who previously received a Kasai procedure (KP) (32.4% vs 44.7%, respectively; P = 0.092) obviously increased, and significantly more parents were willing to treat their children with LT (73% vs 86%, respectively; P = 0.027). Grafts from living donors (102/122, 83.6%) were the most commonly used graft type. Surgical complications (16/25, 64.0%) were the main reason for posttransplant mortality. Among the living donor liver transplantation recipients (n = 102), the incidence of surgical complications was significantly reduced (34.1% vs 15.5%, respectively; P = 0.029) and survival rates of patients and grafts were greatly improved (81.8% vs 89.7%, respectively, at 1 year; 75.0% vs 87.8%, respectively, at 3 years; P = 0.107) from stage I to stage II., Conclusion: The status of surgical treatments for BA has been changing in mainland China. Favorable midterm outcomes after LT were achieved as centers gained greater technical experience.

Objective: To develop a reasonable protocol for childhood rhabdomyosarcoma (RS) to improve the prognosis of this disease., Methods: The protocol RS-99, developed on the base of pathological examination, clinical staging and grouping was used for 30 RS patients, 15 male and 15 female, aged 53 months (15-180 months). For the low-risk patients the regimen VCP and IeV were used alternately for 6 treatment courses and then local radiotherapy was given, for the median and high risk patients, regimen AVCP and IEV were used alternately for 6 courses, local radiotherapy and selective operation were performed, and then DEV and IeV were used alternately for 6 courses, and for the high-risk patients DEV and IeV were used alternately for 18 courses in total and then hematopoietic stem cell transplantation was conducted., Results: Twenty-three of the 30 patients reached complete response (CR) 17 of which remained in CR for 37 (32-92) months, and 7 of the 30 patients achieved partial response (PR) but their condition worsened later. Relapse was seen in 6 patients 15 (7-38) months later. The 5 year event-free survival (EFS) rate was 47% and the overall survival (OS) rate was 52%. All the 10 stage I and II patients, 5 of the 8 stage III patients, and only 2 of the 12 stage IV patients still remained in CR., Conclusion: The protocol RS-99 is effective on the RS at stages I, II, and III, however, is ineffective on the disease at stage IV.

Aim: To explore the possibility of the replacement of the gag gene between human immunodeficiency virus and bovine immunodeficiency virus, to achieve chimeric virions, and thereby gain a new kind of AIDS vaccine based on BHIV chimeric viruses., Methods: A series of chimeric BHIV proviral DNAs differing in the replacement regions in gag gene were constructed, and then were transfected into 293T cells. The expression of chimeric viral genes was detected at the RNA and protein level. The supernatant of 293T cell was ultra centrifuged to detect the probable chimeric virion. Once the chimeric virion was detected, its biological activities were also assayed by infecting HIV-sensitive MT4 cells., Results: Four chimeric BHIV proviral DNAs were constructed. Genes in chimeric viruses expressed correctly in transfected 293T cells. All four constructs assembled chimeric virions with different degrees of efficiency. These virions had complete structures common to retroviruses and packaged genomic RNAs, but the cleavages of the precursor Gag proteins were abnormal to some extent. Three of these virions tested could attach and enter into MT4 cells, and one of them could complete the course of reverse transcription. Yet none of them could replicate in MT4 cells., Conclusion: The replacement of partial gag gene of HIV with BIV gag gene is feasible. Genes in chimeric BHIVs are accurately expressed, and virions are assembled. These chimeric BHIVs (proviral DNA together with virus particles) have the potential to become a new kind of HIV/AIDS vaccine.

Objective: Chimeric human/bovine immunodeficiency virus (HBIV) cDNA was constructed by replacing HIV tat and LTR with bovine immunodeficiency virus (BIV) tat and LTR to study the activity of BIV tat and LTR in the chimerae., Methods: The target fragments of BIV tat, LTR and HIV gag, pol, env were respectively amplified by using PCR and sequentially inserted into pBluescript SK(+) vector. The chimeric clone was transfected into human MT4 cells. The transcript and gene expression of the HBIV chimeric virus were detected by using RT-PCR and a reverse transcriptase assay, respectively., Results: BIV tat mRNA and HIV gag mRNA were detected. The reverse transcriptase activity of the chimeric virus was analyzed in the fluctuation curve., Conclusions: In chimeric HBIV cDNA transfected MT?4 cells, BIV tat and HIV gag were transcripted. The reverse transcriptase of the chimeric virus had biological activity. These data suggest that in MT4 cells, BIV LTR had promoter activity and BIV tat had the function of transactivation in the chimeric virus. The study of the chimeric virus with infectivity is in progress.

Aim: To explore a rapid and easy sequencing method for hepatitis C virus (HCV) genome and establish a new sequencing method in China., Methods: Polymerase chain reaction (PCR) was combined with a DNA sequencing technique. PCR products were purified by agarose gel electrophoresis, polyacrylamide gel electrophoresis (PAGE) and polyethylene glycol (PEG) respectively. Then, in the presence of a 5' labeling PCR primer, purified PCR products were directly sequenced. By this method, HCV NS5b cDNA from two HCV infected individuals (HC-42 and HC-49) were sequenced., Results: PCR directed sequencing worked best using PCR amplified DNA purified by electrophoresis as a sequencing template. When sequencing a large number of templates, the purification step can be bypassed by using a lower concentration of dNTPs (40 μmol of each dNTP) and primers (10 pmol of each primer) in the first stage of PCR. The aliquot of the first stage of PCR mixture was then directly used for amplification of chain terminated products but the sequencing ladders generated were of low intensity. Polyethylene glycol (PEG) could not remove nonspecific products of PCR, which affected the sequencing result to a certain extent and generated a background in sequencing ladders. Compared with the reported HCVJ and HC-C2, a new three nucleotide deletion was found in HC-42., Conclusion: PCR directed sequencing is a rapid, simple and effective method, especially for sequencing large samples. A three nucleotide deletion was first reported.