Gene-Modified Stem Cells for Spinal Cord Injury: a Promising Better Alternative Therapy.

Stem cell therapy holds great promise for the treatment of spinal cord injury (SCI), which can reverse neurodegeneration and promote tissue regeneration via its pluripotency and ability to secrete neurotrophic factors. Although various stem cell-based approaches have shown certain therapeutic effects when applied to the treatment of SCI, their clinical efficacies have been disappointing. Thus, it is an urgent need to further enhance the neurological benefits of stem cells through bioengineering strategies including genetic engineering. In this review, we summarize the progress of stem cell therapy for SCI and the prospect of genetically modified stem cells, focusing on the genome editing tools and functional molecules involved in SCI repair, trying to provide a deeper understanding of genetically modified stem cell therapy and more applicable clinical strategies for SCI repair.

Induced pluripotent stem cell technology for spinal cord injury: a promising alternative therapy.

Spinal cord injury has long been a prominent challenge in the trauma repair process. Spinal cord injury is a research hotspot by virtue of its difficulty to treat and its escalating morbidity. Furthermore, spinal cord injury has a long period of disease progression and leads to complications that exert a lot of mental and economic pressure on patients. There are currently a large number of therapeutic strategies for treating spinal cord injury, which range from pharmacological and surgical methods to cell therapy and rehabilitation training. All of these strategies have positive effects in the course of spinal cord injury treatment. This review mainly discusses the problems regarding stem cell therapy for spinal cord injury, including the characteristics and action modes of all relevant cell types. Induced pluripotent stem cells, which represent a special kind of stem cell population, have gained impetus in cell therapy development because of a range of advantages. Induced pluripotent stem cells can be developed into the precursor cells of each neural cell type at the site of spinal cord injury, and have great potential for application in spinal cord injury therapy.

Gerstmann-Sträussler-Scheinker disease: A case report.

BACKGROUND: Gerstmann-Sträussler-Scheinker (GSS) disease is an inherited prion disease that is clinically characterized by the early onset of progressive cerebellar ataxia. The incidence of GSS is extremely low and it is particularly rare in China. Therefore, clinicians may easily confuse this disease with other diseases that also cause ataxia, resulting in its under-diagnosis or misdiagnosis. CASE SUMMARY: Here, we report the first case of genetically diagnosed GSS disease in Northeast China. The patient exhibited typical ataxia and dysarthria 2.5 years after symptom onset. However, magnetic resonance imaging of the brain and spinal cord revealed a normal anatomy. Screening results for the spinocerebellar ataxia gene were also negative. We thus proposed to expand the scope of genetic screening to include over 200 mutations that can cause ataxia. A final diagnosis of GSS was presented and the patient was followed for more than 3.5 years, during which we noted imaging abnormalities. The patient gradually exhibited decorticate posturing and convulsions. We recommended administration of oral sodium valproate, which resolved the convulsions. CONCLUSION: Patients with inherited ataxia should be considered for a diagnosis of GSS via genetic testing at an early disease stage.

Modeling the temporal dynamics of intertidal benthic infauna biomass with environmental factors: Impact assessment of land reclamation.

Anthropogenic activities such as land reclamation are threatening tidal marshes worldwide. This study's hypothesis is that land reclamation in a semi-enclosed bay alters the seasonal dynamics of intertidal benthic infauna, which is a key component in the tidal marsh ecosystem. Mai Po Tidal Marsh, Deep Bay, Pearl River Estuary, China was used as a case study to evaluate the hypothesis. Ecological models that simulate benthic biomass dynamics with governing environmental factors were developed, and various scenario experiments were conducted to evaluate the impact of reclamations. Environmental variables, selected from the areas of hydrodynamics, meteorology, and water quality based on correlation analysis, were used to generate Bayesian regression models for biomass prediction. The best-performing model, which considered average water age (i.e., a hydrodynamic indicator of estuarine circulation) in the previous month, salinity variation (i.e., standard deviation of salinity), and the total sunny period in the current month, captured well both seasonal and yearly trends in the benthic infauna observations from 2002 to 2008. This model was then used to simulate biomass dynamics with varying inputs of water age and salinity variation from coastal numerical models of different reclamation scenarios. The simulation results suggest that the reclamation in 2007 decreased the spatial and annual average benthic infauna biomass in the tidal marsh by 20%, which agreed with the 28% biomass decrease recorded by field survey. The range of biomass seasonal variation also decreased significantly from 2.1 to 230.5g/m2 (without any reclamation) to 1.2 to 131.1g/m2 (after the 2007 reclamation), which further demonstrates the substantial ecological impact of reclamation. The ecological model developed in this study could simulate seasonal biomass dynamics and evaluate the ecological impact of reclamation projects. It can therefore be applied to evaluate the ecological impact of coastal engineering projects for tidal marsh management, conservation, and restoration.

Neuroprotective Effect of Salvianolic Acids against Cerebral Ischemia/Reperfusion Injury.

This study investigated the neuroprotective effect of salvianolic acids (SA) against ischemia/reperfusion (I/R) injury, and explored whether the neuroprotection was dependent on mitochondrial connexin43 (mtCx43) via the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathway. In vitro, we measured astrocyte apoptosis, mitochondrial membrane potential, and also evaluated the morphology of astrocyte mitochondria with transmission electron microscopy. In vivo, we determined the cerebral infarction volume and measured superoxide dismutase (SOD) activity and malondialdehyde (MDA) content. Additionally, mtCx43, p-mtCx43, AKT, and p-AKT levels were determined. In vitro, we found that I/R injury induced apoptosis, decreased cell mitochondrial membrane potential (MMP), and damaged mitochondrial morphology in astrocytes. In vivo, we found that I/R injury resulted in a large cerebral infarction, decreased SOD activity, and increased MDA expression. Additionally, I/R injury reduced both the p-mtCx43/mtCx43 and p-AKT/AKT ratios. We reported that both in vivo and in vitro, SA ameliorated the detrimental outcomes of the I/R. Interestingly, co-administering an inhibitor of the PI3K/AKT pathway blunted the effects of SA. SA represents a potential treatment option for cerebral infarction by up-regulating mtCx43 through the PI3K/AKT pathway.

Predictive Values of Red Blood Cell Distribution Width in Assessing Severity of Chronic Heart Failure.

BACKGROUND This retrospective study was performed to evaluate the value of baseline red blood cell distribution width (RDW) for predicting the severity of chronic heart failure (CHF) compared with N-terminal prohormone brain natriuretic peptide (NT-ProBNP) and other hematological and biochemical parameters. MATERIAL AND METHODS Hematological and biochemical parameters were obtained from 179 patients with New York Heart Association (NYHA) CHF class I (n=44), II (n=39), III (n=41), and IV (n=55). Receiver operator characteristic (ROC) curves were used for assessing predictive values. RESULTS RDW increased significantly in class III and IV compared with class I (14.3±2.3% and 14.3±1.7% vs. 12.9±0.8%, P<0.01). Areas under ROCs (AUCs) of RDW and NT-ProBNP for class IV HF were 0.817 and 0.840, respectively. RDW was markedly elevated in the mortality group compared with the survival group (13.7±1.7 vs. 15.8±1.8, P<0.01). The predictive value of RDW was lower than that of NT-ProBNP but was comparable to white blood cell (WBC), neutrophil (NEU), lymphocyte (L), and neutrophil/lymphocyte ratio (N/L) for mortality during hospitalization, with AUCs of 0.837, 0.939, 0.858, 0.891, 0.885, and 0.885, respectively. RDW and NT-proBNP showed low predictive values for repeated admission (≥3). RDW was an independent risk factor for mortality (OR=2.531, 95% CI: 1.371-4.671). CONCLUSIONS RDW increased significantly in class III and IV patients and in the mortality group. The predictive value of RDW is comparable to NT-proBNP for class IV and lower than that of NT-proBNP for mortality. Elevated RDW is an independent risk factor for mortality.

Mechanism of Mitochondrial Connexin43's Protection of the Neurovascular Unit under Acute Cerebral Ischemia-Reperfusion Injury.

We observed mitochondrial connexin43 (mtCx43) expression under cerebral ischemia-reperfusion (I/R) injury, analyzed its regulation, and explored its protective mechanisms. Wistar rats were divided into groups based on injections received before middle cerebral artery occlusion (MCAO). Cerebral infarction volume was detected by 2,3,5-triphenyltetrazolim chloride staining, and cell apoptosis was observed by transferase dUTP nick end labeling. We used transmission electron microscopy to observe mitochondrial morphology and determined superoxide dismutase (SOD) activity and malondialdehyde (MDA) content. MtCx43, p-mtCx43, protein kinase C (PKC), and p-PKC expression were detected by Western blot. Compared with those in the IR group, cerebral infarction volumes in the carbenoxolone (CBX) and diazoxide (DZX) groups were obviously smaller, and the apoptosis indices were down-regulated. Mitochondrial morphology was damaged after I/R, especially in the IR and 5-hydroxydecanoic acid (5-HD) groups. Similarly, decreased SOD activity and increased MDA were observed after MCAO; CBX, DZX, and phorbol-12-myristate-13-acetate (PMA) reduced mitochondrial functional injury. Expression of mtCx43 and p-mtCx43 and the p-Cx43/Cx43 ratio were significantly lower in the IR group than in the sham group. These abnormalities were ameliorated by CBX, DZX, and PMA. MtCx43 may protect the neurovascular unit from acute cerebral IR injury via PKC activation induced by mitoKATP channel agonists.

Cortical spreading depression-induced preconditioning in the brain.

Cortical spreading depression is a technique used to depolarize neurons. During focal or global ischemia, cortical spreading depression-induced preconditioning can enhance tolerance of further injury. However, the underlying mechanism for this phenomenon remains relatively unclear. To date, numerous issues exist regarding the experimental model used to precondition the brain with cortical spreading depression, such as the administration route, concentration of potassium chloride, induction time, duration of the protection provided by the treatment, the regional distribution of the protective effect, and the types of neurons responsible for the greater tolerance. In this review, we focus on the mechanisms underlying cortical spreading depression-induced tolerance in the brain, considering excitatory neurotransmission and metabolism, nitric oxide, genomic reprogramming, inflammation, neurotropic factors, and cellular stress response. Specifically, we clarify the procedures and detailed information regarding cortical spreading depression-induced preconditioning and build a foundation for more comprehensive investigations in the field of neural regeneration and clinical application in the future.

Bacterial growth efficiency in a partly eutrophicated bay of South China Sea: Implication for anthropogenic impacts and potential hypoxia events.

Bacterial metabolism plays a dual role [bacterial production (BP) and bacterial respiration (BR)] in the aquatic ecosystem and potentially leads to hypoxia in the coastal eutrophic area. Bacterial growth efficiency (BGE) is an important index showing the contribution of bacterial metabolism to marine biological production and carbon budget in the pelagic ecosystem. In this study, the spatial and seasonal variety as well as diurnal variation dynamics of BGE and associated ecological characteristics were investigated in a partly eutrophicated subtropical bay (the Daya Bay) located in the northern South China Sea. Furthermore, the relationship between bacterial metabolism and potential hypoxia event was analyzed. The average BGE was 0.14 and 0.22 in summer and winter, respectively, which was lower than the mean value ever reported in other coastal and estuarine waters. The diurnal variations of BGE and BP were widely fluctuated in the Daya Bay, with approximately 3-8 fold variation of BP and 2-3 fold variation of BR in different seasons, suggesting the importance of short-term ecological dynamics on evaluating the long-term ecological processes in the coastal waters. BR was the predominant contributor to the bacterial carbon demand; however, the variation of BGE was controlled by BP in both seasons. BGE was always high in the near-shore waters with higher eutrophic level and more active BP and BR. The bacterial metabolism could deplete dissolved oxygen (DO) in the Daya bay within about 9 days when the water body was enclosed and photosynthesis was prohibited. Therefore, low DO concentration and potential hypoxia was more likely to be found in the near-shore waters of the Daya Bay in summer, since the water was stratified and enclosed with poor water exchange capacity in this area. While in winter, hypoxia seldom occurred due to vertical mixing throughout the water column. Further biological-physical coupling research is recommended to find out the detailed formation mechanism of hypoxia in the bay, and to predict the potential hypoxia events and their environmental impacts in the future.

Planktonic community structure during a harmful bloom of Phaeocystis globosa in a subtropical bay, with special reference to the ciliate assemblages.

Planktonic community structure was investigated during outbreak of harmful Phaeocystis globosa bloom in a subtropical bay, the Maowei Sea, South China Sea. The phytoplankton assemblage was numerically dominated by colonial P. globosa, with its abundance ranging from 1.23 × 10(8) to 11.12 × 10(8) cells m(-3) and contributing nearly 90 % to the total abundance. Totally 66 mesozooplankton (>169 µm) and 19 ciliates species were recorded, with the densities ranged from 169 to 1633 ind m(-3) and 74 to 1118 cells L(-1), respectively. The dominant species for mesozooplankton were Copepoda (larvae), Bestiola sinicus, B. amoyensis, Macrura (larvae) and Acartia spinicauda, respectively. The ciliate assemblage was numerically dominated by Codonella rapa, Strombidium globosaneum and Mesodinium rubrum. During the bloom, P. globosa seemed to be negatively affected by the nutrient phosphate significantly (p < 0.05). However, no correlation between P. globosa and ciliate assemblage was detected, but P. globosa was negatively correlated with total biomass of mesozooplankton and abundance of B. sinicus (p < 0.05), suggesting that P. globosa was uncoupled from the grazing by both ciliates and mesozooplankton when appearing as colonies form. On the other hand, both positive and negative correlations among the dominant groups of mesozooplankton and ciliates were observed (p < 0.05) which possibly indicated that the predation of mesozooplankton upon ciliates might be strengthened during the Phaeocystis bloom and the complex effect also varied from species to species.

Genetic population structure of polychaeta Neanthes glandicincta (Nereididae) of the Mai Po Inner Deep Bay Ramsar Site, Hong Kong.

Neanthes glandicincta (Nereididae, Polychaeta) is the first numerically dominant benthic infauna in the Mai Po international Ramsar site, Hong Kong and also an economically important species for food source of birds and fishes. In present study, highly conserved nuclear ribosomal DNA (SSU and LSU rDNA) and mitochondrial COI gene were employed to study the population structure of N. glandicincta in the subtropical mudflat. The specimens were collected from five localities in February 2006, February-August 2007 and preserved at -80 °C, methanol or formalin, respectively. DNA extraction efficiency was the highest in fresh materials and lowest in formalin-fixed samples. The 18S (1774 bp), 28S D1 (383 bp) and COI genes were sequenced and analyzed. Both 18S and 28S D1 rDNA were highly conserved and showed no difference among the populations, whereas COI gene exhibited relatively high-level intraspecific polymorphism (2.2 %). The population from onshore and near mangrove station was phylogenetic different from other sites, indicating restricted gene exchange between the region of river mouth and mangrove forest. The mangrove may form a barrier for the dispersal of pelagic/benthic larvae of the population, which indicates that the population genetic difference is related to different habitats.

Diaporine, a novel endophyte-derived regulator of macrophage differentiation.

Diaporine (1), an unprecedented symmetric polyketide, was characterized from the endophytic fungus. The structure was determined by extensive spectroscopic analyses. Diaporine can inhibit significantly the differentiation of macrophages and has potential to induce conversion from the M2 to the M1 phenotype, in addition to regulation of the TLR4-MAPK signal pathway and PPARγ activity.

A new recombinant hybrid polypeptide and its immunologic adjuvant activity for inactivated infectious bursal disease vaccine.

Both bursin (Lys-His-Gly-NH2) and Gagnon's peptides (Lys-Asn-Pro-Tyr) can induce B-cell differentiation. However, it is unclear whether a recombinant hybrid polypeptide consisting of a tandem array of 14 copies of bursin and two copies of Gagnon's peptide can induce the proliferative activity of lymphocytes. Here, this recombinant hybrid polypeptide was expressed in Escherichia coli and purified by SDS-PAGE. Various assays showed that it not only promoted B-lymphocyte proliferation in vitro but also increased the titers of antibodies directed against infectious bursal disease virus fourfold in the sera of chickens vaccinated with the inactivated infectious bursal disease virus vaccine. The recombinant hybrid polypeptide also reduced the pathological lesions in the bursa of Fabricius caused by infectious bursal disease virus BC6/85. Our results show that this recombinant hybrid polypeptide may be a promising immune adjuvant.

Adult-onset leukoencephalopathy with brain stem and spinal cord involvement in Chinese Han population: a case report and literature review.

Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL) is a recently described disorder with an autosomal recessive mode of inheritance. We report a case of rare adult-onset LBSL with typical magnetic resonance imaging (MRI) features. The DARS2 gene mutation analysis has identified a c. 228-20_21delTTinsC (p.R76SfsX5) mutation and a c. 850G > A (p. 284E > K) mutation. With glucocorticosteroid treatment the patient has had improvement in bladder symptoms. This is the first reported adult-onset LBSL case in the Chinese Han population. A review of the literature suggests that brain lactate elevation in adult-onset LBSL is lower than early-onset cases (P < 0.01), and early-onset cases show mild intelligence and cognition decline. These observations suggest that age of onset and brain lactate levels probably influence the prognosis of LBSL.

Evaluation of sampling sizes on the intertidal macroinfauna assessment in a subtropical mudflat of Hong Kong.

In this study, two types of sediment cores with different diameters were used to collect sediment samples from an intertidal mudflat in Hong Kong to investigate the influence of sampling unit on the quantitative assessment of benthic macroinfaunal communities. Both univariate and multivariate analyses were employed to detect differences in sampling efficiencies by the two samplers through total abundance and biomass, species richness and diversity, community structure, relative abundance of major taxa of the infaunal community. The species-area curves were further compared to find out the influence of the sampling units. Results showed that the two sampling devices provided similar information on the estimates of species diversity, density and species composition of the benthos in main part of the mudflat where the sediment was fine and homogenous; but at the station which contained coarse sand and gravels, the significant differences were detected between the quantitative assessments of macrobenthic infauna by the two samplers. Most importantly, the species-area curves indicated that more and smaller samples were better in capturing more species than less large ones when comparing an equal sampling area. Therefore, the efficiency of the sampler largely depended on the sediment properties, and sampling devices must be chosen based on the physical conditions and desired levels of precision on the organisms of the sampling program.

Evidence of iron cyanides as supplementary nitrogen source to rice seedlings.

The effect of iron cyanides on activities of nitrate reductase (NR) and glutamine synthetase (GS) of plants was investigated. Young rice seedlings (Oryza sativa L. cv. XZX 45) were grown in the nutrient solutions containing KNO(3) or NH(4)Cl and treated with ferro-cyanide [K(4)Fe(CN)(6)] or ferri-cyanide [K(3)Fe(CN)(6)]. Total cyanide and free cyanide in solutions and in plant materials were analyzed. Activities of NR and GS in different parts of plants were assayed in vivo. Results indicated that all rice seedlings exposed to either ferro- or ferri-cyanide showed positive growth. The phyto-assimilation rates of both iron cyanide species by rice seedlings were positively correlated to the doses supplied. Seedlings grown on NO(3)(-) showed significantly higher assimilatory potential for both ferro- and ferri-cyanide than those on NH(4)(+). Rice seedlings grown on NH(4)(+)-containing nutrient solution accumulated more cyanide in plant materials, majority being in roots rather than shoots, than these grown on NO(3)(-)-containing nutrient solution, suggesting that the presence of ammonium (NH(4)(+)) in the nutrient solution caused a negative impact on botanical assimilation of both iron cyanides. Sensitivity of NR and GS in rice seedlings exposed to ferro- and ferri-cyanide was identical, where conspicuous effects were only observed at the highest concentration supplied. The evidence offered here suggests that both iron cyanides can be a supplementary source of nitrogen to plant nutrition.

Novel polymorphism of internal transcribed spacers (ITS) and their utilization in phylogenetic analysis of Neanthes glandicincta (Annelida: Polychaeta: Nereididae).

Sequences of internal transcribed spacers (ITS1 and ITS2) are increasingly being used to infer phylogenetic relationships at or below species levels. Here we report a novel case of ITS polymorphism within Neanthes glandicincta (Annelida: Polychaeta: Nereididae). Two types of ITS sequence (Type I and Type II) were cloned and sequenced, which showed significant differences both in nucleotide composition and length. Variations of these two types sequences also differed from each other with Type I was highly divergent while Type II was highly conserved. Phylogenetic trees inferred from ITS1 and ITS2 sequences showed striking discrepancy in N. glandicincta. Non-concerted evolution of multi-gene is suggested to be responsible for the high degree of polymorphism in ITS regions. Due to the two divergent types of ITS presented within a single N. glandicincta individual, the utilization of ITS regions for delineation of population or closely related species cannot be substantiated. The finding of different types of ITS in a single individual also stresses the need for analyzing a large number of clones whenever ITS sequences obtained by PCR amplification and cloning are being used in phylogenetic reconstruction.

Occurrence of brackish water phytoplankton species at a closed coral reef in Nansha Islands, South China Sea.

The phytoplankton assemblage of Zhubi Reef, a closed coral reef in Nansha Islands (South China Sea, SCS) was studied in June 2007. A total of 92 species belonging to 53 genera and four phyla have been identified. The dominant taxa in the lagoon were the diatom Chaetoceros and cyanobacteria Nostoc and Microcystis, while in reef flats were cyanobacteria Trichodesmium erythraeum, dinoflagellates Gymnodinium and Prorocentrum. The species richness and diversity were consistently lower in the lagoon than in reef flats. Classification and nMDS ordination also revealed significant dissimilarity in phytoplankton community structure between the reef flat and lagoon, with statistical difference in species composition and abundance between them (ANOSIM, p=0.025). Nutrient concentrations also spatially varied, with ammonium-enrichment in the lagoon, while high Si-concentration existed in reef flat areas. Both nutrient levels and currents in SCS may play important roles in determining the composition and distribution of microalgae in Zhubi Reef and SCS.

Serum, liver, and kidney proteomic analysis for the alloxan-induced type I diabetic mice after insulin gene transfer of naked plasmid through electroporation.

Gene therapy has been reported to be effective in treating diabetes mellitus (DM), while little has been found out about the functional protein changes since. The liver and kidney play important roles in glucose absorption, metabolism, and excretion. Changes in the two organs may reflect pathologic alterations during DM, while the serum has a direct connection with most organs and pathological changes. We used alloxan to induce diabetic mice, electrotranferred the insulin gene into their sural muscles, and discovered that their blood glucose decreased to normal level. Consequently, proteomic approaches were applied to evaluate protein changes in the liver, kidney, and serum of normal, diabetic, and gene transferred mice. Forty-three proteins were found either up-regulated or down-reglulated in the liver, kidney, and serum of the alloxan-induced type I diabetic mice. Only five proteins in the liver, five proteins in the kidney, and seven proteins in the serum of diabetic mice were found to be back-regulated to normal levels after gene transfer. These back-regulated proteins are involved in lipid and glucose metabolism, associated with phosphorylation, signal transduction, oxidation, and immune inflammation. Our findings might promote a better understanding for the mechanism of DM, and provide novel targets for estimating the effects of gene therapy.

Highly efficient photoactivation of Mn-depleted photosystem II by imidazole-liganded manganese complexes.

The oxygen-evolving complex (OEC) of Mn-depleted photosystem II (PSII) can be reconstituted in the presence of exogenous Mn or a Mn complex under weak illumination, a process called photoactivation. Synthetic Mn complexes could provide a powerful system to analyze the assembly of the OEC. In this work, four mononuclear Mn complexes, [(terpy)2Mn(II)(OOCH3)] x 2 H2O (where terpy is 2,2':6',2''-terpyridine), Mn(II)(bzimpy)2, Mn(II)(bp)2(CH3CH2OH)2 [where bzimpy is 2,6-bis(2-benzimidazol-2-yl)pyridine] and [Mn(III)(HL)(L)(py)(CH3OH)]CH3OH (where py is pyridine) were used in photoactivation experiments. Measurements of the photoreduction of 2,6-dichorophenolindophenol and oxygen evolution demonstrate that photoactivation is more efficient when Mn complexes are used instead of MnCl2 in reconstructed PSII preparations. The most efficient recoveries of oxygen evolution and electron transport activities are obtained from a complex, [Mn(III)(HL)(L)(py)(CH3OH)]CH3OH, that contains both imidazole and phenol groups. Its recovery of the rate of oxygen evolution is as high as 79% even in the absence of the 33-kDa peptide. The imidazole ligands of the Mn complex probably accelerate P680*+ reduction and consequently facilitate the process of photoactivation. Also, the strong intermolecular hydrogen bond probably facilitates interaction with the Mn-depleted PSII via reorganization of the hydrogen-bonding network, and therefore promotes the recovery of oxygen evolution and electron transport activities.