[Geographic environment-related research advances on children's myopia: intraocular and environmental exposure factors and analytical methods]

Myopia has become a global phenomenon, transitioning into a significant public health issue of worldwide reach. The escalating prevalence of myopia may lead to an increase in the incidence of related complications, potentially resulting in irreversible vision damage for individuals. This not only causes considerable economic strain on societies but also poses a serious threat to vital sectors like national defense. This review outlines various external and internal exposure factors related to childhood myopia. It places particular focus on the analysis of the interaction between geographical environmental factors and internal exposure factors, and examines the limitations of applying traditional methods in studying the relationship between childhood myopia and geographical environmental factors. The paper also introduces two spatial regression methodologies based on frequency estimation and Bayesian estimation, summarizing their feasibility and merits when applied in the study of external exposure elements related to childhood myopia. Finally, it provides a fresh perspective on regional childhood myopia prevention strategies that are conscious of geographical environmental factors.

Hybrid Quantum Mechanical/Molecular Mechanical Methods For Studying Energy Transduction in Biomolecular Machines

Hybrid quantum mechanical/molecular mechanical (QM/MM) methods have become indispensable tools for the study of biomolecules. In this article, we briefly review the basic methodological details of QM/MM approaches and discuss their applications to various energy transduction problems in biomolecular machines, such as long-range proton transports, fast electron transfers, and mechanochemical coupling. We highlight the particular importance for these applications of balancing computational efficiency and accuracy. Using several recent examples, we illustrate the value and limitations of QM/MM methodologies for both ground and excited states, as well as strategies for calibrating them in specific applications. We conclude with brief comments on several areas that can benefit from further efforts to make QM/MM analyses more quantitative and applicable to increasingly complex biological problems.

[A case of delayed peripheral neuropathy caused by diquat poisoning]

Diquat is a kind of conductive contact-killing herbicides. The damage of central nervous system is relatively common, but the peripheral neuropathy caused by diquat has not been reported yet. In September 2021, we treated a patient with diquat poisoning. During the hospitalization, the patient was diagnosed with peripheral neuropathy. Therapy for peripheral nerve injury was given on the basis of conventional treatment of poisoning. The patient was discharged after his condition was stable. The follow-up showed that the peripheral neuropathy of patient was better than before. According to the condition of this patient, it is suggested that we should not only protect the function of gastrointestinal tract, liver, kidney, and central nervous system early, but should also pay attention to the damage of peripheral nervous system in clinical work. We should intervene earlier to improve the prognosis of patients.

First report of Atractylodes lancea leaf spot caused by Fusarium acuminatum in China

Atractylodes lancea Thunb. DC (cangzhu) is a traditional Chinese medicinal plant (Cai et al., 2020). In June 2020, leaf spots were observed in A. lancea plants at the Chongqing Institute of Medicinal Plant Cultivation located in Nanchuan District, Chongqing, China (29°8'26.46″ N, 107°13'23'21″ E). Approximately 75% of the plants displayed leaf spot, partial leaf wilting, and stunted growth, and some plants died. To determine the cause of this disease, five typical leaf spots were cut into small pieces. The pieces were successively surface-disinfected with 0.5% NaClO for 1 min and 75% ethanol for 30 s, washed thrice with sterile water, and placed on potato dextrose agar (PDA) to incubate at 25 ℃. These isolates initially formed abundant white aerial mycelium, then gradually developed a rose pigmentation with a brownish color in the center and grayish rose at the periphery of the colony (Li et al. 2019). Mycelial tips were picked and placed on carnation leaf agar (CLA) and inoculated for 7 days. The macroconidia of the isolates were slender, distinctively curved in the bottom half of the apical cell, and sickle-shaped, with 3-4 septa. They ranged in size from 16.68-26.49 × 1.48-2.34 μm (n=50). The microconidia were fusiform with or without one septum. Their size ranged from 6.19-11.02 × 1.25-1.43 μm (n=50) (Li et al. 2019). The morphological characteristics of the isolates were consistent with those of Fusarium spp. PCR amplification and DNA sequencing of the internal transcribed spacer (ITS) region and β-tubulin (TUB2) gene were performed using the primers ITS1/ITS4 (White et al. 1990) and Bt-2a/Bt-2b (Robideau et al. 2011), respectively. BLASTn analysis revealed that the ITS sequences of the isolates were 100% identical to those of the F. acuminatum isolates from the Fusarium MLST database (http://isolate.fusariumdb.org/guide.php). Further analysis revealed that the TUB2 sequences were 99.14% identical to those of the F. acuminatum strain S16 isolates (MF662644) from the GeneBank database of the NCBI server. Based on the morphology and sequence analyses, the isolates were identified as F. acuminatum. Pathogenicity tests were conducted on 1.5-year-old A. lancea plants by inoculating spore suspensions under greenhouse conditions (25°C). For this, wound were made on leaves by piercing with sterilized toothpicks. 30 μl of spore suspension containing 2 × 106 conidia/ml was placed on each wound. Wounds on the leaves of control plants were inoculated with 10 μl of sterile distilled water. There were three plants for each treatment. After incubation at 25 °C for 5 days in a greenhouse, the leaves of the treated plants all showed partial wilting, consistent with the field observations. No symptoms were observed in controlled plants. The fungi were again isolated from the symptomatic tissues and were identical to the original isolate. The experiment was repeated twice with similar results. Pathogenicity symptoms were similar to what was first observed in the field and the isolated fungi were verified based on morphological characteristics, thus fulfilling Koch's postulate. To the best of our knowledge, this is the first time that A. lancea leaf spot caused by F. acuminatum has been discovered in China. The leaf spot caused by F. acuminatum on A. lancea has serious yield loss, and proper control measures should be applied.

First report of Cladosporium cladosporioides causing leaf blight on Sambucus chinensis in China

Sambucus chinensis, belonging to the Caprifoliaceae family, is an economically large herb plant that is widely cultivated in southern China for its good ornamental characteristics, edible properties, and medicinal values. In July 2021, symptoms of leaf spot were observed on Sambucus chinensis plants in two fields of Chongqing Medicinal Botanical Garden (29º8'26" N, 107º13'23" E) in Nanchuan city, Chongqing, China. Disease incidence was approximately 35 and 50% for each field. The symptoms were initially yellow or black irregular spots on leaves, and then increased to larger dark brown lesions. Finally, the entire infected leaf was blighted, withering, curl and abscission. Ten blight leaves were randomly sampled from fields. Tissues were cut into small pieces and surface sterilized with 75% ethanol for 30 s and sterilized in 2% sodium hypochlorite for 2 min, rinsed thrice with sterile distilled water, plated on potato dextrose agar (PDA) plates, and incubated at 25°C for 7 days in the dark. Later, 20 isolates were obtained from the infected leaves and had similar characteristics. Three isolates were randomly selected (CQ81, CQ82, CQ83) for the further study. Colonies on PDA were olive-green to brown with a velvety texture. Conidia (n=30) were pale- to olive-brown, smooth to verruculose and produced in long, branched chains which were easily disarticulate, single celled, and elliptical to limoniform, and measured as 2.51~4.29 × 1.63~2.14 μm. Conidiophores were solitary, straight or flexous, often unbranched. The DNA of three isolates were extracted and the internal transcribed spacer (ITS) region and translation elongation factor 1-alpha (TEF1-α) were sequenced using primer pairs ITS1/ITS4 (White et al. 1990) and EF1-728F/EF1-986R (Carbone and Kohn 1999), respectively. The sequences of three isolates were 100% identical, and one representative isolate CQ82 were deposited in GenBank (ON387641, ITS; and ON409522, TEF). BLASTn analysis of these sequences showed 99 to 100% nucleotide identity with the sequences of C. cladosporioides CPC 14705 in Korea (Bensch et al. 2010). Phylogenetic analysis using Neighbor-joining method and concatenated sequences (ITS +TEF1) with MEGA7 placed isolate CQ82 in C. cladosporioides with 99% bootstrap support. On the basis of morphological and molecular characteristics, the isolates were identified as C. cladosporioides (Bensch et al. 2010; Nam et al. 2015). A total of sixteen healthy potted plants of S. chinensis were conducted for the pathogenicity test. Eight plants were selected and one shoot of each plant was randomly used for inoculation. Leaves from the shoot of each plant were brushed with 106 conidia/ml suspension of isolate CQ82. Another 8 plants were performed in the same procedure, inoculated with sterile distilled water as control. All plants were covered with plastic bags for two days and then arranged in a greenhouse with 80% relative humidity at 25°C. The pathogenicity test was repeated thrice. After 15 days inoculation, the similar symptoms were observed on the inoculated leaves, whereas controls remained healthy. The pathogen was reisolated from blight tissue and identified as C. cladosporioides by the methods described above. Although this fungus was previously reported to cause leaf disease on many plants (Meneses et al. 2018; Sun et al. 2017), this is the first report of C. cladosporioides causing leaf blight on S. chinensis in China. This study will establish a foundation for controlling the disease.

SlNAC6, A NAC transcription factor, is involved in drought stress response and reproductive process in tomato

Tomato plants are susceptible to drought stress, but the mechanism involved in this process still remains poorly understood. In the present study, we demonstrated that SlNAC6, a nuclear-localized protein induced by exogenous abscisic acid (ABA) or polyethylene glycol (PEG) stress treatment, plays a positive role in tomato plant response to PEG stress. Down-regulation of SlNAC6 (SlNAC6-RNAi) resulted in a semidwarf phenotype, and the SlNAC6-RNAi lines showed reduced tolerance to PEG stress, exhibiting a higher water loss rate and degree of oxidative damage, as well as lower values of proline content and antioxidant enzyme activity, when compared with those in wild type (WT). In contrast, overexpression of SlNAC6 (SlNAC6-OE) leads to a significant delay of growth, and the SlNAC6-OE lines showed greatly enhanced tolerance to PEG stress concomitant with a lower water loss rate and degree of oxidative damage, as well as higher values of proline content and antioxidant enzyme activity. Further study showed that the transcription level of ABA signaling-related genes and the ABA content are respectively decreased or increased in SlNAC6-RNAi and SlNAC6-OE seedlings, as verified by multiple physiological parameters, such as stomatal conductance, water loss rate, seed germination, and root length. Moreover, overexpression of SlNAC6 can accelerate tomato fruit ripening. Collectively, this study demonstrates SlNAC6 exerts important roles in tomato development, drought stress response, and fruit ripening processes, some of them perhaps partly through modulating an ABA-mediated pathway, which implies SlNAC6 may hold the potential applications in improving agronomic traits of tomato or other Solanaceae crops.

Prognostic value of late gadolinium enhancement in arrhythmogenic right ventricular cardiomyopathy: a meta-analysis

AIM

To assess systematically the prognostic value of cardiac magnetic resonance imaging (CMRI) in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC).

MATERIALS AND METHODS

The full text of studies of the clinical efficacy of late gadolinium enhancement (LGE) in ARVC was retrieved in multiple databases. Stata 14 was adopted for meta-analysis and bias analysis. Heterogeneity was assessed with the I² statistic.

RESULTS

After exclusions, 561 patients were included in five studies, and the eligibility criteria were met. The meta-analysis suggested that there was a significant difference between LGE positive and negative patients with ARVC in all-cause mortality (relative risk [RR] = 4.78, 95% confidence interval [CI] = 1.41, 16.23, p=0.012; p for heterogeneity = 0.692, I² = 0%); major adverse cardiovascular events (MACE) (RR=2.48, 95% CI = 1.24, 4.96, p=0.010; p for heterogeneity = 0.596, I² = 0%); ventricular tachycardia (RR=3.13, 95% CI = 1.69, 5.78, p<0.001; p for heterogeneity = 0.825, I² = 0%); implanted cardiac defibrillators (RR=3.15, 95% CI = 1.69, 5.87], p<0.001; p for heterogeneity = 0.353, I² = 9.4%).

CONCLUSION

LGE in ARVC patients is a predictor of all-cause mortality and MACE.

Bacillus circulans GN03 Alters the Microbiota, Promotes Cotton Seedling Growth and Disease Resistance, and Increases the Expression of Phytohormone Synthesis and Disease Resistance-Related Genes

Plant growth-promoting bacteria (PGPB) are components of the plant rhizosphere that promote plant growth and/or inhibit pathogen activity. To explore the cotton seedlings response to Bacillus circulans GN03 with high efficiency of plant growth promotion and disease resistance, a pot experiment was carried out, in which inoculations levels of GN03 were set at 10⁴ and 10⁸ cfu^⋅mL^-1. The results showed that GN03 inoculation remarkably enhanced growth promotion as well as disease resistance of cotton seedlings. GN03 inoculation altered the microbiota in and around the plant roots, led to a significant accumulation of growth-related hormones (indole acetic acid, gibberellic acid, and brassinosteroid) and disease resistance-related hormones (salicylic acid and jasmonic acid) in cotton seedlings, as determined with ELISA, up-regulated the expression of phytohormone synthesis-related genes (EDS1, AOC1, BES1, and GA20ox), auxin transporter gene (Aux1), and disease-resistance genes (NPR1 and PR1). Comparative genomic analyses was performed between GN03 and four similar species, with regards to phenotype, biochemical characteristics, and gene function. This study provides valuable information for applying the PGPB alternative, GN03, as a plant growth and disease-resistance promoting fertilizer.

Morning Serum Cortisol as a Predictor for the HPA Axis Recovery in Cushing's Disease

BACKGROUND

The suppressed hypothalamic-pituitary-adrenal (HPA) axis after successful surgery for Cushing's disease (CD) will recover in almost all patients. We aimed to identify the predictive factors for HPA axis recovery in CD patients with postoperative remission. Design and Methods. This observational retrospective cross-sectional study enrolled 69 CD patients with postoperative remission in Huashan Hospital from 2015 to 2019. All subjects had a detailed clinical evaluation. The low-dose ACTH stimulation test (LDT) was conducted as the gold standard for assessing the HPA axis function.

RESULTS

Peak cortisol in LDT was found only to be positively correlative with morning serum cortisol (MSC) (ρ=0.451, p < 0.001). The MSC was higher (p < 0.001), and the median postoperative course was significantly longer (p=0.025) in the patients with the recovered HPA axis function compared with unrecovered patients. The AUC value of MSC for predicting the recovery of the HPA axis was 0.701, and the optimal cutoff was 6.25 μg/dl (sensitivity 85.19% and specificity 47.62%). Other useful cutoff values were 10.74 μg/dl (specificity 100%) and 4.18 μg/dl (sensitivity 100%). Besides, combined with the postoperative course, the AUC values were higher than MSC alone (0.935 vs. 0.701, p < 0.001).

CONCLUSIONS

MSC is a viable first-step diagnostic predictor for HPA axis recovery in CD patients with postoperative remission. For the patients with cortisol levels between 4.18 and 10.74 μg/dl, a confirmatory test should be conducted. When the MSC level was 10.74 μg/dl or greater, the replacement therapy could be discontinued.

Clinical and molecular insights into Glanzmann's thrombasthenia in China

Glanzmann's thrombasthenia (GT) is a rare bleeding disorder characterized by spontaneous mucocutaneous bleeding. The disorder is caused by quantitative or qualitative defects in integrin αIIbβ3 (encoded by ITGA2B and ITGB3) on the platelet and is more common in consanguineous populations. However, the prevalence rate and clinical characteristics of GT in non-consanguineous populations have been unclear. We analyzed 97 patients from 93 families with GT in the Han population in China. This analysis showed lower consanguinity (18.3%) in Han patients than other ethnic populations in GT-prone countries. Compared with other ethnic populations, there was no significant difference in the distribution of GT types. Han females suffered more severe bleeding and had a poorer prognosis. We identified a total of 43 different ITGA2B and ITGB3 variants, including 25 previously unidentified, in 45 patients. These variants included 14 missense, 4 nonsense, 4 frameshift, and 3 splicing site variants. Patients with the same genotype generally manifested the same GT type but presented with different bleeding severities. This suggests that GT clinical phenotype does not solely depend on genotype. Our study provides an initial, yet important, clinical and molecular characterization of GT heterogeneity in China.

Slater Insulator in Iridate Perovskites with Strong Spin-Orbit Coupling

The perovskite SrIrO_{3} is an exotic narrow-band metal owing to a confluence of the strengths of the spin-orbit coupling (SOC) and the electron-electron correlations. It has been proposed that topological and magnetic insulating phases can be achieved by tuning the SOC, Hubbard interactions, and/or lattice symmetry. Here, we report that the substitution of nonmagnetic, isovalent Sn^{4+} for Ir^{4+} in the SrIr_{1-x}Sn_{x}O_{3} perovskites synthesized under high pressure leads to a metal-insulator transition to an antiferromagnetic (AF) phase at T_{N}≥225  K. The continuous change of the cell volume as detected by x-ray diffraction and the λ-shape transition of the specific heat on cooling through T_{N} demonstrate that the metal-insulator transition is of second order. Neutron powder diffraction results indicate that the Sn substitution enlarges an octahedral-site distortion that reduces the SOC relative to the spin-spin exchange interaction and results in the type-G AF spin ordering below T_{N}. Measurement of high-temperature magnetic susceptibility shows the evolution of magnetic coupling in the paramagnetic phase typical of weak itinerant-electron magnetism in the Sn-substituted samples. A reduced structural symmetry in the magnetically ordered phase leads to an electron gap opening at the Brillouin zone boundary below T_{N} in the same way as proposed by Slater.

QM/MM Analysis of Transition States and Transition State Analogues in Metalloenzymes

Enzymology is approaching an era where many problems can benefit from computational studies. While ample challenges remain in quantitatively predicting behavior for many enzyme systems, the insights that often come from computations are an important asset for the enzymology community. Here we provide a primer for enzymologists on the types of calculations that are most useful for mechanistic problems in enzymology. In particular, we emphasize the integration of models that range from small active-site motifs to fully solvated enzyme systems for cross-validation and dissection of specific contributions from the enzyme environment. We then use a case study of the enzyme alkaline phosphatase to illustrate specific application of the methods. The case study involves examination of the binding modes of putative transition state analogues (tungstate and vanadate) to the enzyme. The computations predict covalent binding of these ions to the enzymatic nucleophile and that they adopt the trigonal bipyramidal geometry of the expected transition state. By comparing these structures with transition states found through free energy simulations, we assess the degree to which the transition state analogues mimic the true transition states. Technical issues worth treating with care as well as several remaining challenges to quantitative analysis of metalloenzymes are also highlighted during the discussion.

The efficacy of high-intensity, focused ultrasound treatment for non-neoplastic epithelial disorders of the vulva

Non-neoplastic epithelial disorders of the vulva (NNEDV) are common types of vulval lesions. Although corticosteroids represent a first-line treatment for NNEDV, concerns exist about the safety associated with long-term topical corticosteroid use. Recently, several clinical trials have identified high-intensity focused ultrasound (HIFU) as a promising treatment modality for NNEDV. The aim of this multi-center, randomized, controlled clinical trial was to investigate the efficacy of HIFU therapy in women with NNEDV based on histological alterations. We enrolled patients who were clinically diagnosed with NNEDV. They were randomized into 2 treatment groups: 1) halcinonide for 3 months or 2) HIFU once. A total of 123 patients were biopsied both prior to and after the therapy, and 62 and 61 patients were assigned to the HIFU and halcinonide groups, respectively. The histological changes were then analyzed. After the treatments, the therapeutic effects were observed in both groups. Comparing the diagnosis and alterations in lichenoid and sclerotic patterns and in chronic inflammation, we found statistically significant differences. Furthermore, when compared with the halcinonide group, the HIFU group exhibited enhanced curative effects that were statistically significant (P = 0.039). Based on the histological evidence from this randomized, controlled trial, HIFU represents an effective method for the treatment of NNEDV.

Rab3A, Rab27A, and Rab35 regulate different events during mouse oocyte meiotic maturation and activation

Rab family members play important roles in membrane trafficking, cell growth, and differentiation. Almost all components of the cell endomembrane system, the nucleus, and the plasma membrane are closely related to RAB proteins. In this study, we investigated the distribution and functions of three members of the Rab family, Rab3A, Rab27A, and Rab35, in mouse oocyte meiotic maturation and activation. The three Rab family members showed different localization patterns in oocytes. Microinjection of siRNA, antibody injection, or inhibitor treatment showed that (1) Rab3A regulates peripheral spindle and cortical granule (CG) migration, polarity establishment, and asymmetric division; (2) Rab27A regulates CG exocytosis following MII-stage oocyte activation; and (3) Rab35 plays an important role in spindle organization and morphology maintenance, and thus meiotic nuclear maturation. These results show that Rab proteins play important roles in mouse oocyte meiotic maturation and activation and that different members exert different distinct functions.

PDK1/Akt/PDE4D axis identified as a target for asthma remedy synergistic with β2 AR agonists by a natural agent arctigenin

BACKGROUND

Asthma is a heterogenetic disorder characterized by chronic inflammation with variable airflow obstruction and airway hyper-responsiveness. As the most potent and popular bronchodilators, β2 adrenergic receptor (β2 AR) agonists bind to the β2 ARs that are coupled via a stimulatory G protein to adenylyl cyclase, thereby improving cAMP accumulation and resulting in airway smooth muscle relaxation. We previously demonstrated arctigenin had a synergistic function with the β2 AR agonist, but the target for this remained elusive.

METHOD

Chemical proteomics capturing was used to enrich and uncover the target of arctigenin in human bronchial smooth muscle cells, and reverse docking and molecular dynamic stimulation were performed to evaluate the binding of arctigenin and its target. In vitro enzyme activities and protein levels were demonstrated with special kits and Western blotting. Finally, guinea pig tracheal muscle segregation and ex vivo function were analysed.

RESULTS

Arctigenin bound to PDK1 with an ideal binding free energy -25.45 kcal/mol and inhibited PDK1 kinase activity without changing its protein level. Additionally, arctigenin reduced PKB/Akt-induced phosphorylation of PDE4D, which was first identified in this study. Attenuation of PDE4D resulted in cAMP accumulation in human bronchial smooth muscle. The inhibition of PDK1 showed a synergistic function with β2 AR agonists and relaxed the constriction of segregated guinea pig tracheal muscle.

CONCLUSIONS

The PDK1/Akt/PDE4D axis serves as a novel asthma target, which may benefit airflow obstruction.

Dielectric function of two-phase colloid-polymer nanocomposite

The plasmon resonance of metal nanoparticles determines their optical response in the visible spectral range. Many details such as the electronic properties of gold near the particle surface and the local environment of the particles influence the spectra. We show how the cheap but highly precise fabrication of composite nanolayers by spin-assisted layer-by-layer deposition of polyelectrolytes can be used to investigate the spectral response of gold nanospheres (GNS) and gold nanorods (GNR) in a self-consistent way, using the established Maxwell-Garnett effective medium (MGEM) theory beyond the limit of homogeneous media. We show that the dielectric function of gold nanoparticles differs from the bulk value and experimentally characterize the shape and the surrounding of the particles thoroughly by SEM, AFM and ellipsometry. Averaging the dielectric functions of the layered surrounding by an appropriate weighting with the electric field intensity yields excellent agreement for the spectra of several nanoparticles and nanorods with various cover-layer thicknesses.

TRAF3IP3, a novel autophagy up-regulated gene, is involved in marginal zone B lymphocyte development and survival

Tumour necrosis factor receptor-associated factor 3 (TRAF3) interacting protein 3 (TRAF3IP3; also known as T3JAM) is expressed specifically in immune organs and tissues. To investigate the impact of TRAF3IP3 on immunity, we generated Traf3ip3 knock-out (KO) mice. Interestingly, these mice exhibited a significant reduction in the number of common lymphoid progenitors (CLPs) and inhibition of B cell development in the bone marrow. Furthermore, Traf3ip3 KO mice lacked marginal zone (MZ) B cells in the spleen. Traf3ip3 KO mice also exhibited a reduced amount of serum natural antibodies and impaired T cell-independent type II (TI-II) responses to trinitrophenol (TNP)-Ficoll antigen. Additionally, our results showed that Traf3ip3 promotes autophagy via an ATG16L1-binding motif, and MZ B cells isolated from mutant mice showed a diminished level of autophagy and a high rate of apoptosis. These results suggest that TRAF3IP3 contributes to MZ B cell survival by up-regulating autophagy, thereby promoting the TI-II immune response.

The injury resistant ability of melanopsin-expressing intrinsically photosensitive retinal ganglion cells

Neurons in the mammalian retina expressing the photopigment melanopsin have been identified as a class of intrinsically photosensitive retinal ganglion cells (ipRGCs). This discovery more than a decade ago has opened up an exciting new field of retinal research, and following the initial identification of photosensitive ganglion cells, several subtypes have been described. A number of studies have shown that ipRGCs subserve photoentrainment of circadian rhythms. They also influence other non-image forming functions of the visual system, such as the pupillary light reflex, sleep, cognition, mood, light aversion and development of the retina. These novel photosensitive neurons also influence form vision by contributing to contrast detection. Furthermore, studies have shown that ipRGCs are more injury-resistant following optic nerve injury, in animal models of glaucoma, and in patients with mitochondrial optic neuropathies, i.e., Leber’s hereditary optic neuropathy and dominant optic atrophy. There is also an indication that these cells may be resistant to glutamate-induced excitotoxicity. Herein we provide an overview of ipRGCs and discuss the injury-resistant character of these neurons under certain pathological and experimental conditions.

Lyn regulates cytotoxicity in respiratory epithelial cells challenged by cigarette smoke extracts

Cigarette smoking is associated with a series of lung diseases such as cancer, chronic obstructive pulmonary disease (COPD), and asthma. Despite the intense interest, the underlying molecular mechanism in smoking-related diseases is incompletely understood. Here, we show that Lyn is involved in cytotoxicity of respiratory epithelial cells induced by cigarette smoke extracts (CSE), an in vitro culture model for evaluating tobacco toxicity. In addition, exposure to CSE promotes the activation of JAK2 and STAT1, which is responsible for CSE-induced cytotoxicity. Moreover, a Lyn specific siRNA, Lyn dominant negative construct and pharmacological inhibitor all alleviated CSE-induced cytotoxicity in lung cells to different extents, respectively. Furthermore, Lyn also influences the phagocytosis of bacteria by murine alveolar macrophages, extending its impact on innate immunity. Taken together, these findings indicate that Lyn may play a role in the regulation of cigarette smoking-induced lung cell death, and may be a potential novel therapeutic target for cigarette smoking related lung diseases.

Cardiac mass in Behçet's disease

Cardiac mass is a rare manifestation of Behçet's disease (BD). Intracardiac thrombosis, endomyocardiofibrosis, endocardial fibroelastosis, inflammatory mass and cystic change have been reported as different entities of cardiac mass in BD. Here we presented 6 cases of this rare manifestation of BD. The clinical and pathological features were reviewed.

Disruption and formation of surface salt bridges are coupled to DNA binding by the integration host factor: a computational analysis

Revealing the thermodynamic driving force of protein-DNA interactions is crucial to the understanding of factors that dictate the properties and function of protein-DNA complexes. For the binding of DNA to DNA-wrapping proteins, such as the integration host factor (IHF), Record and co-workers proposed that the disruption of a large number of preexisting salt bridges is coupled with the binding process [Holbrook, J. A., et al. (2001) J. Mol. Biol. 310, 379]. To test this proposal, we have conducted explicit solvent MD simulations (multiple ∼25-50 ns trajectories for each salt concentration) to examine the behavior of charged residues in IHF, especially concerning their ability to form salt bridges at different salt concentrations. Of the 17 cationic residues noted by Record and co-workers, most are engaged in salt bridge interactions for a significant portion of the trajectories, especially in the absence of salt. This observation suggests that, from a structural point of view, their proposal is plausible. However, the complex behaviors of charged residues observed in the MD simulations also suggest that the unusual thermodynamic characteristics of IHF-DNA binding likely arise from the interplay between complex dynamics of charged residues both in and beyond the DNA binding site. Moreover, a comparison of MD simulations at different salt concentrations suggests that the strong dependence of the IHF-DNA binding enthalpy on salt concentration may not be due to a significant decrease in the number of stable salt bridges in apo IHF at high salt concentrations. In addition to the Hofmeister effects quantified in more recent studies of IHF-DNA binding, we recommend consideration of the variation of the enthalpy change of salt bridge disruption at different salt concentrations. Finally, the simulation study presented here explicitly highlights the fact that the electrostatic properties of DNA-binding proteins can be rather different in the apo and DNA-bound states, which has important implications for the design of robust methods for predicting DNA binding sites in proteins.

Growth and characterization of ceria thin films and Ce-doped γ-Al2O3 nanowires using sol-gel techniques

γ-Al(2)O(3) is a well known catalyst support. The addition of Ce to γ-Al(2)O(3) is known to beneficially retard the phase transformation of γ-Al(2)O(3) to α-Al(2)O(3) and stabilize the γ-pore structure. In this work, Ce-doped γ-Al(2)O(3) nanowires have been prepared by a novel method employing an anodic aluminium oxide (AAO) template in a 0.01 M cerium nitrate solution, assisted by urea hydrolysis. Calcination at 500 °C for 6 h resulted in the crystallization of the Ce-doped AlOOH gel to form Ce-doped γ-Al(2)O(3) nanowires. Ce(3+) ions within the nanowires were present at a concentration of < 1 at.%. On the template surface, a nanocrystalline CeO(2) thin film was deposited with a cubic fluorite structure and a crystallite size of 6-7 nm. Characterization of the nanowires and thin films was performed using scanning electron microscopy, transmission electron microscopy, electron energy loss spectroscopy, x-ray photoelectron spectroscopy and x-ray diffraction. The nanowire formation mechanism and urea hydrolysis kinetics are discussed in terms of the pH evolution during the reaction. The Ce-doped γ-Al(2)O(3) nanowires are likely to find useful applications in catalysis and this novel method can be exploited further for doping alumina nanowires with other rare earth elements.

CHARMM: the biomolecular simulation program

CHARMM (Chemistry at HARvard Molecular Mechanics) is a highly versatile and widely used molecular simulation program. It has been developed over the last three decades with a primary focus on molecules of biological interest, including proteins, peptides, lipids, nucleic acids, carbohydrates, and small molecule ligands, as they occur in solution, crystals, and membrane environments. For the study of such systems, the program provides a large suite of computational tools that include numerous conformational and path sampling methods, free energy estimators, molecular minimization, dynamics, and analysis techniques, and model-building capabilities. The CHARMM program is applicable to problems involving a much broader class of many-particle systems. Calculations with CHARMM can be performed using a number of different energy functions and models, from mixed quantum mechanical-molecular mechanical force fields, to all-atom classical potential energy functions with explicit solvent and various boundary conditions, to implicit solvent and membrane models. The program has been ported to numerous platforms in both serial and parallel architectures. This article provides an overview of the program as it exists today with an emphasis on developments since the publication of the original CHARMM article in 1983.

The role of macrophages in optic nerve regeneration

Following injury to the nervous system, the activation of macrophages, microglia, and T-cells profoundly affects the ability of neurons to survive and to regenerate damaged axons. The primary visual pathway provides a well-defined model system for investigating the interactions between the immune system and the nervous system after neural injury. Following damage to the optic nerve in mice and rats, retinal ganglion cells, the projection neurons of the eye, normally fail to regenerate their axons and soon begin to die. Induction of an inflammatory response in the vitreous strongly enhances the survival of retinal ganglion cells and enables these cells to regenerate lengthy axons beyond the injury site. T cells modulate this response, whereas microglia are thought to contribute to the loss of retinal ganglion cells in this model and in certain ocular diseases. This review discusses the complex and sometimes paradoxical actions of blood-borne macrophages, resident microglia, and T-cells in determining the outcome of injury in the primary visual pathway.

The Effects of Open Lung Ventilation on Respiratory Mechanics and Haemodynamics in Atelectatic Infants after Cardiopulmonary Bypass

Acute lung injury (ALI) frequently occurs in infants after cardiopulmonary bypass (CPB) surgery and it sometimes develops into acute respiratory distress syndrome in critically ill infants, which can be life threatening. This study investigated the effects of open lung ventilation on the haemodynamics and respiratory mechanics of 64 infants (34 males; 30 females) with a mean ± SD age of 8.3 ± 0.3 months who developed ALI following CPB surgery. Open lung ventilation significantly improved the respiratory mechanics and oxygenation parameters of the infants, including the partial pressure of oxygen in arterial blood (PaO2), the ratio of PaO2/FiO2 (fraction of inspired oxygen), peak inspiratory pressure, static compliance and airway resistance. It is concluded that open lung ventilation can greatly improve oxygenation and respiratory mechanics in infants with ALI following CPB surgery.

Differentiation block of oligodendroglial progenitor cells as a cause for remyelination failure in chronic multiple sclerosis

Impaired function/differentiation of progenitor cells might provide an explanation for the limited remyelination observed in the majority of chronic multiple sclerosis lesions. Here, we establish that in the normal adult human CNS, the transcription factors Nkx2.2 and Olig2 are strongly expressed in progenitor cells while mature oligodendrocytes are characterized by low levels of Olig2 or Nkx2.2. In vitro studies confirmed the expression of Olig2 in oligodendroglial progenitor cells and mature oligodendrocytes while astrocytes, microglial cells and neurons were negative for Olig2. In early multiple sclerosis lesions, we found Olig2-positive progenitor cells throughout all lesion stages and in periplaque white matter (PPWM). The number of progenitors in PPWM was significantly increased compared with the white matter from controls. In chronic multiple sclerosis lesions progenitor cells were still present, however, in significantly lower numbers than in early multiple sclerosis lesions. A subpopulation of progenitor cells in early multiple sclerosis lesions and PPWM but not in control cases co-expressed NogoA, a marker of mature oligodendrocytes. The co-expression of these two markers suggested that these cells were maturing oligodendrocytes recently recruited from the progenitor pool. In contrast, in chronic multiple sclerosis lesions maturing progenitors were only rarely present. In summary, we provide evidence that a differentiation block of oligodendroglial progenitors is a major determinant of remyelination failure in chronic multiple sclerosis lesions.

Possible role of hydrogen sulfide on the preservation of donor rat hearts

OBJECTIVE

The aim of this study was to observe the preservative effect of hydrogen sulfide (H2S) on donor rat hearts.

MATERIALS AND METHODS

The hearts of 24 Sprague-Dawley rats were perfused on a Langendorff perfusion column for 30 minutes. We calculated and recorded the left ventricular-developed pressure (LVDP), and positive and negative derivatives of left ventricular systolic pressure (LVSP; +dP/dt and -dP/dt). Hearts were then arrested and stored for 6 hours at 4 degrees C: group 1, Krebs-Henseleit (KH) solution; group 2, KH solution with 1 micromol/L NaHS; group 3, KH solution with 1 micromol/L NaHS and 10 micromol/L glibenclamide; group 4, St. Thomas II solution. Hearts were transferred back to the Langendorff column. After stabilizing for 30 minutes, LV performance was assessed as before. The donor hearts were kept for pathological study including myocardial water ratio, ATP content, and myocyte apoptosis index.

RESULTS

The recovery rates of +dp/dtmax, -dp/dtmax, and LVDP of groups 2 and 4 were much better than those of groups 1 and 3. The hearts contracted immediately after reperfusion in group 4. Ventricular fibrillation was seen before contraction in the other 3 groups, with the longest duration in group. No significant difference in myocardial water ratio was found. The ATP content was the highest in group 2. Apoptosis was observed in the 4 groups with the lowest apoptosis index in group 2.

CONCLUSIONS

H2S has a protective effect on rat donor hearts at the concentration of 1 micromol/L. The protective effect is better than that of St. Thomas II solution. The protective effect of H2S can be blocked by glibenclamide.

Differential roles of phosphatidylinositol 3-kinase/akt pathway in retinal ganglion cell survival in rats with or without acute ocular hypertension

Intraocular pressure (IOP) elevation has often been used as an experimental model to study mechanisms underlying retinal ganglion cell (RGC) death associated with ocular ischemic injury and glaucoma. The aim of the present study, using both in vitro and in vivo approaches, was to investigate the role of phosphatidylinositol 3-kinase (PI3K)/akt pathway in RGC viability in normal rats and rats following transient IOP elevation. For in vivo studies, pathway inhibitors were administered intravitreally on days 3, 9, and 15 post-2-h IOP elevation at 110 mm Hg. Toward the end of the 3-week examination period, the fluorescent dye Fluorogold was used to retrogradely label surviving RGCs. In order to examine the role of macrophages that were recruited into the eye following the pathway inhibition, clodronate liposomes were used to deplete phagocytic cells in the eye. PI3K/akt pathway activity and location in the retina were examined using Western blot and immunohistochemistry, respectively. Here we showed that PI3K/akt inhibitors 2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride (LY294002) and KY12420 at low concentrations (2 microM or 20 microM) did not influence RGC survival but caused RGC loss at high concentration (200 muM) in retinal explants derived from intact rats. In contrast, both LY294002 and KY12420 at 20 microM led to RGC loss in retinal explants derived from IOP-elevated eyes. A detrimental action of phagocytic cells on RGC survival was also seen in these retinas. In vivo results confirmed the detrimental actions of PI3K/akt inhibition and macrophages on RGC survival in IOP-elevated, but not intact eyes even with high concentration of LY294002. Low level of PI3K/akt activity was detected in the ganglion cell layer (GCL) in intact retina. Acute IOP elevation activated PI3K/akt pathway in the inner nuclear layer and GCL including RGCs. This study thus demonstrates that PI3K/akt pathway mediates RGC survival after IOP elevation but not under normal condition.

Regulatory network motifs and hotspots of cancer genes in a mammalian cellular signalling network

Mutations or overexpression of signalling genes can result in cancer development and metastasis. In this study, we manually assembled a human cellular signalling network and developed a robust bioinformatics strategy for extracting cancer-associated single nucleotide polymorphisms (SNPs) using expressed sequence tags (ESTs). We then investigated the relationships of cancer-associated genes [cancer-associated SNP genes, known as cancer genes (CG) and cell mobility genes (CMGs)] in a signalling network context. Through a graph-theory-based analysis, we found that CGs are significantly enriched in network hub proteins and cancer-associated genes are significantly enriched or depleted in some particular network motif types. Furthermore, we identified a substantial number of hotspots, the three- and four-node network motifs in which all nodes are either CGs or CMGs. More importantly, we uncovered that CGs are enriched in the convergent target nodes of most network motifs, although CMGs are enriched in the source nodes of most motifs. These results have implications for the foundations of the regulatory mechanisms of cancer development and metastasis.

A critical evaluation of different QM/MM frontier treatments with SCC-DFTB as the QM method

The performance of different link atom based frontier treatments in QM/MM simulations was evaluated critically with SCC-DFTB as the QM method. In addition to the analysis of gas-phase molecules as in previous studies, an important element of the present work is that chemical reactions in realistic enzyme systems were also examined. The schemes tested include all options available in the program CHARMM for SCC-DFTB/MM simulation, which treat electrostatic interactions due to the MM atoms close to the QM/MM boundary in different ways. In addition, a new approach, the divided frontier charge (DIV), has been implemented in which the partial charge associated with the frontier MM atom ("link host") is evenly distributed to the other MM atoms in the same group. The performance of these schemes was evaluated based on properties including proton affinities, deprotonation energies, dipole moments, and energetics of proton transfer reactions. Similar to previous work, it was found that calculated proton affinities and deprotonation energies of alcohols, carbonic acids, amino acids, and model DNA bases are very sensitive to the link atom scheme; the commonly used single link atom approach often gives error on the order of 15 to 20 kcal/mol. Other schemes give better and, on average, mutually comparable results. For proton transfer reactions, encouragingly, both activation barriers and reaction energies are fairly insensitive (within a typical range of 2-4 kcal/mol) to the link atom scheme due to error cancellation, and this was observed for both gas-phase and enzyme systems. Therefore, the effect of using different link atom schemes in QM/MM simulations is rather small for chemical reactions that conserve the total charge. Although the current study used an approximate DFT method as the QM level, the observed trends are expected to be applicable to QM/MM methods with use of other QM approaches. This observation does not mean to encourage QM/MM simulations without careful benchmark in the study of specific systems, rather it emphasizes that other technical details, such as the treatment of long-range electrostatics, tend to play a more important role and need to be handled carefully.

Strain-specific differences in the effects of cyclosporin A and FK506 on the survival and regeneration of axotomized retinal ganglion cells in adult rats

The immune response can influence neuronal viability and plasticity after injury, effects differing in strains of rats with different susceptibility to autoimmune disease. We assessed the effects of i.p. injections of cyclosporin A (CsA) or FK506 on adult retinal ganglion cell (RGC) survival and axonal regeneration into peripheral nerve (PN) autografted onto the cut optic nerve of rats resistant (Fischer F344) or vulnerable (Lewis) to autoimmune disease. Circulating and tissue CsA and FK506 levels were similar in both strains. Three weeks after autologous PN transplantation the number of viable beta-III tubulin-positive RGCs was significantly greater in CsA- and FK506-treated F344 rats compared with saline-injected controls. RGC survival in Lewis rats was not significantly altered. In F344 rats, retrograde labeling of RGCs revealed that CsA or FK506 treatment significantly increased the number of RGCs that regenerated an axon into a PN autograft; however these agents had no beneficial effect on axonal regeneration in Lewis rats. PN grafts in F344 rats also contained comparatively more pan-neurofilament immunoreactive axons. In both strains, 3 weeks after transplantation CsA or FK506 treatment resulted in increased retinal macrophage numbers, but only in F344 rats was this increase significant. At this time-point PN grafts in both strains contained many macrophages and some T cells. T cell numbers in Lewis rats were significantly greater than in F344 animals. The increased RGC axonal regeneration seen in CsA- or FK506-treated F344 but not Lewis rats shows that modulation of immune responses after neurotrauma has complex and not always predictable outcomes.

Administration of donor-derived mesenchymal stem cells can prolong the survival of rat cardiac allograft

BACKGROUND

Mesenchymal stem cells (MSCs) are multipotent adult elements that have recently been shown to have profound immunomodulatory effects both in vitro and in vivo. Herein we have examined the impact of intravenous infusion of donor MSCs on the survival of transplanted hearts in a rat allograft model.

METHODS

Recipient Fisher344 rats were transplanted with hearts from inbred Wistar rats. Wistar rat MSCs were infused via the tail vein at designated intervals. In vitro mixed lymphocyte reaction (MLR) and cell-mediated lympholysis (CML) assays were performed to assess whether MSCs downregulated T-cell responses in vivo. Real-time polymerase chain reaction (PCR) was used to analyze the Th1/Th2 balance in MSC-treated and control groups.

RESULTS

The MSCs cultured in vitro exhibited multipotential for differentiation. Survival of the allografts was markedly prolonged by administration of MSCs compared with the controls, namely mean survivals of 12.4 vs 6.4 days, respectively. Real-time PCR showed a shift in the Th1/Th2 balance toward Th2. By MLR and CML assays, untreated control rats showed greater alloreactivity than did MSC-treated rats.

CONCLUSION

Our results indicated that MSCs suppressed allogeneic T-cell responses both in vitro and in vivo. Intravenous administration of MSCs prolonged the survival of transplanted hearts, possibly by induction of allograft tolerance through changing the Th1/Th2 balance.

Dynamics of X+CH4 (X=H,O,Cl) reactions: How reliable is transition state theory for fine-tuning potential energy surfaces?

Trajectory calculations run on global potential energy surfaces have shown that the topology of the entrance channel has strong implications on the dynamics of the title reactions. This may explain why huge differences are observed between the rate constants calculated from global dynamical methods and those obtained from local methods that employ the same potential energy surfaces but ignore such topological details. Local dynamics approaches such as transition state-based theories should then be used with caution for fine-tuning potential energy surfaces, especially for fast reactions with polyatomic species since the key statistical assumptions of the theory may not be valid for all degrees of freedom.

AAV-mediated expression of CNTF promotes long-term survival and regeneration of adult rat retinal ganglion cells

We compared the effects of intravitreal injection of bi-cistronic adeno-associated viral (AAV-2) vectors encoding enhanced green fluorescent protein (GFP) and either ciliary neurotrophic factor (CNTF), brain-derived neurotrophic factor (BDNF) or growth-associated protein-43 (GAP43) on adult retinal ganglion cell (RGC) survival and regeneration following (i) optic nerve (ON) crush or (ii) after ON cut and attachment of a peripheral nerve (PN). At 7 weeks after ON crush, quantification of betaIII-tubulin immunostaining revealed that, compared to AAV-GFP controls, RGC survival was not enhanced by AAV-GAP43-GFP but was increased in AAV-CNTF-GFP (mean RGCs/retina: 17 450+/-358 s.e.m.) and AAV-BDNF-GFP injected eyes (10 200+/-4064 RGCs/retina). Consistent with increased RGC viability in AAV-CNTF-GFP and AAV-BDNF-GFP injected eyes, these animals possessed many betaIII-tubulin- and GFP-positive fibres proximal to the ON crush. However, only in the AAV-CNTF-GFP group were regenerating RGC axons seen in distal ON (1135+/-367 axons/nerve, 0.5 mm post-crush), some reaching the optic chiasm. RGCs were immunoreactive for CNTF and quantitative RT-PCR revealed a substantial increase in CNTF mRNA expression in retinas transduced with AAV-CNTF-GFP. The combination of AAV-CNTF-GFP transduction of RGCs with autologous PN-ON transplantation resulted in even greater RGC survival and regeneration. At 7 weeks after PN transplantation there were 27 954 (+/-2833) surviving RGCs/retina, about 25% of the adult RGC population. Of these, 13 352 (+/-1868) RGCs/retina were retrogradely labelled after fluorogold injections into PN grafts. In summary, AAV-mediated expression of CNTF promotes long-term survival and regeneration of injured adult RGCs, effects that are substantially enhanced by combining gene and cell-based therapies/interventions.

Application of I125 Brachytherapy Combined Artificial Joint Prosthesis in Malignant Osteo- and Soft-Tissue Sarcoma

OBJECTIVES

The aim of this study was to evaluate the brachytherapy effectiveness of I(125) seeds combined with artificial prosthesis in malignant sarcoma therapy.

METHODS

The combination of I(125) seeds and artificial prosthesis was implanted to replace tumor section for three clinical cases-2 malignant osteosarcoma patients and 1 malignant soft-tissue tumor patient- through the direct operation.

RESULTS

Approximately 14-18 months after the operation, the results of our post-operational investigation showed that the tumor tissues of 3 patients had been completely removed. The limb functions recovered well. The brachytherapy of the combination of I(125) seeds and artificial prosthesis in malignant tumor improved the curative effect. No tumor existed, and no infection occurred.

CONCLUSIONS

It was demonstrated that this method was safe and easy. No side-effect was observed after the implantation of I(125) seeds. The brachytherapy was proven to be a potential method for patients who were at high risk to recrudesce the malignant osteosarcoma of tumors after the tumor excision.

SEA0400, a novel Na+/Ca2+ exchanger inhibitor, reduces calcium overload induced by ischemia and reperfusion in mouse ventricular myocytes

Given the potential clinical benefit of inhibiting Na+/Ca2+ exchanger (NCX) activity during myocardial ischemia reperfusion (I/R), pharmacological approaches have been pursued to both inhibit and clarify the importance of this exchanger. SEA0400 was reported to have a potent NCX selectivity. Thus, we examined the effect of SEA0400 on NCX currents and I/R induced intracellular Ca2+ overload in mouse ventricular myocytes using patch clamp techniques and fluorescence measurements. Ischemia significantly inhibited inward and outward NCX current (from -0.04+/-0.01 nA to 0 nA at -100 mV; from 0.23+/-0.08 nA to 0.11+/-0.03 nA at +50 mV, n=7), Subsequent reperfusion not only restored the current rapidly but enhanced the current amplitude obviously, especially the outward currents (from 0.23+/-0.08 nA to 0.49+/-0.12 nA at +50 mV, n=7). [Ca2+]i, expressed as the ratio of Fura-2 fluorescence intensity, increased to 138+/-7% (P<0.01) during ischemia and to 210+/-11% (P<0.01) after reperfusion. The change of NCX current and the increase of [Ca2+]i during I/R can be blocked by SEA0400 in a dose-dependent manner with an EC50 value of 31 nM and 28 nM for the inward and outward NCX current, respectively. The results suggested that SEA0400 is a potent NCX inhibitor, which can protect mouse cardiac myocytes from Ca2+ overload during I/R injuries.

Toward theoretical analysis of long-range proton transfer kinetics in biomolecular pumps

Motivated by the long-term goal of theoretically analyzing long-range proton transfer (PT) kinetics in biomolecular pumps, researchers made a number of technical developments in the framework of quantum mechanics-molecular mechanics (QM/MM) simulations. A set of collective reaction coordinates is proposed for characterizing the progress of long-range proton transfers; unlike previous suggestions, the new coordinates can describe PT along highly nonlinear three-dimensional pathways. Calculations using a realistic model of carbonic anhydrase demonstrated that adiabatic mapping using these collective coordinates gives reliable energetics and critical geometrical parameters as compared to minimum energy path calculations, which suggests that the new coordinates can be effectively used as reaction coordinate in potential of mean force calculations for long-range PT in complex systems. In addition, the generalized solvent boundary potential was implemented in the QM/MM framework for rectangular geometries, which is useful for studying reactions in membrane systems. The resulting protocol was found to produce water structure in the interior of aquaporin consistent with previous studies including a much larger number of explicit solvent and lipid molecules. The effect of electrostatics for PT through a membrane protein was also illustrated with a simple model channel embedded in different dielectric continuum environments. The encouraging results observed so far suggest that robust theoretical analysis of long-range PT kinetics in biomolecular pumps can soon be realized in a QM/MM framework.

cAMP regulates axon outgrowth and guidance during optic nerve regeneration in goldfish

Increased cAMP improves neuronal survival and axon regeneration in mammals. Here, we assess cAMP levels and identify activated pathways in a spontaneously regenerating central nervous system. Following optic nerve crush in goldfish, almost all retinal ganglion cells (RGC) survive and regenerate retinotectal topography. Goldfish received injections of a cAMP analogue (CPT-cAMP), a protein kinase A (PKA) inhibitor (KT5720), both compounds combined, or PBS (control). RGC survival in experimental groups was unaffected at any stage. The rate of axon regeneration was accelerated by the activator and decelerated both by the inhibitor and by combined injections, suggesting a PKA-dependent pathway. In addition, errors in regenerate retinotectal topography were observed when agents were applied in vivo and RGC response to the guidance cue ephrin-A5 in vitro was altered by the inhibitor. Our results highlight that therapeutic manipulation of cAMP levels to enhance axonal regeneration in mammals must ensure that topography, and consequently function, is not disrupted.