Widespread white matter microstructural differences in schizophrenia across 4322 individuals: results from the ENIGMA Schizophrenia DTI Working Group

The regional distribution of white matter (WM) abnormalities in schizophrenia remains poorly understood, and reported disease effects on the brain vary widely between studies. In an effort to identify commonalities across studies, we perform what we believe is the first ever large-scale coordinated study of WM microstructural differences in schizophrenia. Our analysis consisted of 2359 healthy controls and 1963 schizophrenia patients from 29 independent international studies; we harmonized the processing and statistical analyses of diffusion tensor imaging (DTI) data across sites and meta-analyzed effects across studies. Significant reductions in fractional anisotropy (FA) in schizophrenia patients were widespread, and detected in 20 of 25 regions of interest within a WM skeleton representing all major WM fasciculi. Effect sizes varied by region, peaking at (d=0.42) for the entire WM skeleton, driven more by peripheral areas as opposed to the core WM where regions of interest were defined. The anterior corona radiata (d=0.40) and corpus callosum (d=0.39), specifically its body (d=0.39) and genu (d=0.37), showed greatest effects. Significant decreases, to lesser degrees, were observed in almost all regions analyzed. Larger effect sizes were observed for FA than diffusivity measures; significantly higher mean and radial diffusivity was observed for schizophrenia patients compared with controls. No significant effects of age at onset of schizophrenia or medication dosage were detected. As the largest coordinated analysis of WM differences in a psychiatric disorder to date, the present study provides a robust profile of widespread WM abnormalities in schizophrenia patients worldwide. Interactive three-dimensional visualization of the results is available at www.enigma-viewer.org.

BAD Ser-155 phosphorylation regulates BAD/Bcl-XL interaction and cell survival

The BH3 domain of BAD mediates its death-promoting activities via heterodimerization to the Bcl-XL family of death regulators. Growth and survival factors inhibit the death-promoting activity of BAD by stimulating phosphorylation at multiple sites including Ser-112 and Ser-136. Phosphorylation at these sites promotes binding of BAD to 14-3-3 proteins, sequestering BAD away from the mitochondrial membrane where it dimerizes with Bcl-XL to exert its killing effects. We report here that the phosphorylation of BAD at Ser-155 within the BH3 domain is a second phosphorylation-dependent mechanism that inhibits the death-promoting activity of BAD. Protein kinase A, RSK1, and survival factor signaling stimulate phosphorylation of BAD at Ser-155, blocking the binding of BAD to Bcl-XL. RSK1 phosphorylates BAD at both Ser-112 and Ser-155 and rescues BAD-mediated cell death in a manner dependent upon phosphorylation at both sites.

Survival- and death-promoting events after transient cerebral ischemia: phosphorylation of Akt, release of cytochrome C and Activation of caspase-like proteases

Release of cytochrome c (cyt c) into cytoplasm initiates caspase-mediated apoptosis, whereas activation of Akt kinase by phosphorylation at serine-473 prevents apoptosis in several cell systems. To investigate cell death and cell survival pathways, the authors studied release of cyt c, activation of caspase, and changes in Akt phosphorylation in rat brains subjected to 15 minutes of ischemia followed by varying periods of reperfusion. The authors found by electron microscopic study that a portion of mitochondria was swollen and structurally altered, whereas the cell membrane and nuclei were intact in hippocampal CA1 neurons after 36 hours of reperfusion. In some neurons, the pattern of immunostaining for cyt c changed from a punctuate pattern, likely representing mitochondria, to a more diffuse cytoplasmic localization at 36 and 48 hours of reperfusion as examined by laser-scanning confocal microscopic study. Western blot analysis showed that cyt c was increased in the cytosolic fraction in the hippocampus after 36 and 48 hours of reperfusion. Consistently, caspase-3-like activity was increased in these hippocampal samples. As demonstrated by Western blot using phosphospecific Akt antibody, phosphorylation of Akt at serine-473 in the hippocampal region was highly increased during the first 24 hours but not at 48 hours of reperfusion. The authors conclude that transient cerebral ischemia activates both cell death and cell survival pathways after ischemia. The activation of Akt during the first 24 hours conceivably may be one of the factors responsible for the delay in neuronal death after global ischemia.

Diuretic efficacy of high dose furosemide in severe heart failure: bolus injection versus continuous infusion

OBJECTIVES

The efficacy of high dose furosemide as a continuous infusion was compared with a bolus injection of equal dose in patients with severe heart failure.

BACKGROUND

The delivery rate of furosemide into the nephron has been proved to be a determinant of diuretic efficacy in healthy volunteers.

METHODS

In a randomized crossover study we compared the efficacy of a continuous infusion of high dose furosemide (mean daily dosage 690 mg, range 250 to 2,000) versus a single bolus injection of an equal dose in 20 patients with severe heart failure. The patients received an equal dosage, either as a single intravenous bolus injection or as an 8-h continuous infusion preceded by a loading dose (20% of total dosage).

RESULTS

Mean (+/- SEM) daily urinary volume (infusion 2,860 +/- 240 ml, bolus 2,260 +/- 150 ml, p = 0.0005) and sodium excretion (infusion 210 +/- 40 mmol, bolus 150 +/- 20 mmol, p = 0.0045) were significantly higher after treatment with continuous infusion than with bolus injection, despite significantly lower urinary furosemide excretion (infusion 310 +/- 60 mg every 24 h, bolus 330 +/- 60 mg every 24 h, p = 0.0195). The maximal plasma furosemide concentration was significantly higher after bolus injection than during continuous infusion (infusion 24 +/- 5 micrograms/ml, bolus 95 +/- 20 micrograms/ml, p < 0.0001). Short-term, completely reversible hearing loss was reported only after bolus injection in 5 patients.

CONCLUSIONS

We conclude that in patients with severe heart failure, high dose furosemide administered as a continuous infusion is more efficacious than bolus injection and causes less ototoxic side effects.

p90(RSK) blocks bad-mediated cell death via a protein kinase C-dependent pathway

Although activation of protein kinase C (PKC) is known to promote cell survival and protect against cell death, the PKC targets and pathways that serve this function have remained elusive. Here we demonstrate that two potent activators of PKC, 12-O-tetradecanoylphorbol-13-acetate and bryostatin, both stimulate phosphorylation of Bad at Ser(112), a site known to regulate apoptotic cell death by interleukin-3. PKC inhibitors but not PI 3-kinase/Akt inhibitors block 12-O-tetradecanoylphorbol-13-acetate-stimulated Bad phosphorylation. PKC isoforms tested in vitro were unable to phosphorylate Bad at Ser(112), suggesting that PKC acts indirectly to activate a downstream Bad kinase. p90(RSK) and family members RSK-2 and RSK-3 are activated by phorbol ester and phosphorylate Bad at Ser(112) both in vitro and in vivo. p90(RSK) stimulates binding of Bad to 14-3-3 and blocks Bad-mediated cell death in a Ser(112)-dependent manner. These findings suggest that p90(RSK) can function in a PKC-dependent pathway to promote cell survival via phosphorylation and inactivation of Bad-mediated cell death.

SingleCellNet: A Computational Tool to Classify Single Cell RNA-Seq Data Across Platforms and Across Species

Single-cell RNA-seq has emerged as a powerful tool in diverse applications, from determining the cell-type composition of tissues to uncovering regulators of developmental programs. A near-universal step in the analysis of single-cell RNA-seq data is to hypothesize the identity of each cell. Often, this is achieved by searching for combinations of genes that have previously been implicated as being cell-type specific, an approach that is not quantitative and does not explicitly take advantage of other single-cell RNA-seq studies. Here, we describe our tool, SingleCellNet, which addresses these issues and enables the classification of query single-cell RNA-seq data in comparison to reference single-cell RNA-seq data. SingleCellNet compares favorably to other methods in sensitivity and specificity, and it is able to classify across platforms and species. We highlight SingleCellNet's utility by classifying previously undetermined cells, and by assessing the outcome of a cell fate engineering experiment.

The inhibitory role of CpG immunostimulatory motifs in cationic lipid vector-mediated transgene expression in vivo

We have previously reported that intravenous administration of cationic lipid-protamine-DNA complexes (LPD) induces production of large quantities of proinflammatory cytokines that are toxic and cause inhibition of transgene expression. Cytokine induction appears to be mediated by the unmethylated CpG sequences since methylation of plasmid DNA significantly decreases the cytokine levels. In this study, the inhibitory role of CpG in lipid-mediated gene transfer was further investigated using chemically well-defined, CpG-containing oligodeoxynucleotides (ODNs). Injection (intravenous) of ODNs formulated in LPD into mice triggered production of proinflammatory cytokines including interferon gamma and TNF-alpha. The potency of CpG-containing ODNs in cytokine induction was affected by its flanking sequences and was significantly reduced when CpG was methylated. Preinjection of ODN-containing LPD led to inhibition of transgene expression in lungs after a subsequent injection of LPD containing plasmid expression vector with luciferase gene. The degree of inhibition correlated with the levels of ODN-triggered cytokines. Finally, intraperitoneal injection of dexamethasone suppressed LPD-induced cytokine production, and led to significantly higher levels of transgene expression on both first and second injection. These studies suggest that mutation of potent CpG motifs in plasmid DNA together with the use of immune suppression agent may represent an effective approach to improve cationic lipid-mediated gene transfer to the lung.

The emergence of a highly transmissible lineage of cbl+ Pseudomonas (Burkholderia) cepacia causing CF centre epidemics in North America and Britain

The rapid increase in Pseudomonas (Burkholderia) cepacia infection in cystic fibrosis (CF) patients suggests epidemic transmission, but the degree of transmissibility remains controversial as conflicting conclusions have been drawn from studies at different CF centres. This report provides the first DNA sequence-based documentation of a divergent evolutionary lineage of P. cepacia associated with CF centre epidemics in North America (Toronto) and Europe (Edinburgh). The involved epidemic clone encoded and expressed novel cable (Cbl) pili that bind to CF mucin. The sequence of the cblA pilin subunit gene carried by the epidemic isolates proved to be invariant. Although it remains to be determined how many distinct, highly transmissible lineages exist, our results provide both a DNA sequence and chromosomal fingerprint that can be used to screen for one such particularly infectious, transatlantic clone.

Increased levels of forkhead box M1B transcription factor in transgenic mouse hepatocytes prevent age-related proliferation defects in regenerating liver

The forkhead box (Fox) family of transcription factors share homology in the winged helix/forkhead DNA-binding domain and play important roles in regulating cellular proliferation, differentiation, longevity, and cellular transformation. Forkhead box M1B (FoxM1B) is a ubiquitously expressed member of the Fox transcription factor family whose expression is restricted to proliferating cells and that mediates hepatocyte entry into DNA synthesis and mitosis during liver regeneration. Recent cDNA microarray studies indicated that age-related defects in cellular proliferation are associated with diminished expression of the FoxM1B transcription factor. Here, we show that increased levels of FoxM1B in regenerating liver of old transgenic mice restore the sharp peaks in hepatocyte DNA replication and mitosis that are the hallmarks of young regenerating mouse liver. Restoration of the young regenerating liver phenotype is associated with increased expression of numerous cell cycle regulatory genes that include cyclin D1, cyclin A2, cyclin F, cyclin B1, cyclin B2, Cdc25B, and p55cdc. Cotransfection assays in the human hepatoma HepG2 cell line demonstrated that FoxM1B protein stimulated expression of both the cyclin B1 and cyclin D1 promoters, suggesting that these cyclin genes are a direct FoxM1B transcriptional target. These results suggest that FoxM1B controls the transcriptional network of genes that are essential for cell division and exit from mitosis. Our results indicate that reduced expression of the FoxM1B transcription factor contributes to the decline in cellular proliferation observed in the aging process.

Comparison of the conformational stability of the molten globule and native states of horse cytochrome c. Effects of acetylation, heat, urea and guanidine-hydrochloride

The molten globule state has been assumed to be a major intermediate of protein folding. We compared the stability of the native and acidic molten globule states of horse ferricytochrome c against heat, urea and guanidine hydrochloride (Gdn-HCl) using the intact species and species modified by various degrees of acetylation of the lysyl epsilon-amino groups. After acetylation, the amino groups cannot protonate at acidic pH. Thermal and urea-induced unfolding transitions measured by far-UV circular dichroism and differential scanning calorimetry showed that, whereas acetylation stabilizes the molten globule state at pH 2, it destabilizes the native state at pH 7, suggesting a difference in their mechanisms of conformational stability. On the other hand, the effects of Gdn-Hcl were remarkable. Contrary to what was expected from the thermal and urea-induced unfolding transitions, the Gdn-HCl-induced unfolding transition of the native state at pH 7 was insensitive to the extent of acetylation. At pH 2, Gdn-HCl at low concentrations stabilized the molten globule state and, at high concentrations, destabilized it. Consideration of the difference in the effects of Gdn-HCl from those of urea or heat indicated that, whereas the net positive charge repulsion destabilizes the molten globule state at pH 2, the local negative charge repulsion produced by acetylation of amino groups, and not the net charge, critically destabilizes the native state at pH 7. These results predict that, because of its ionic nature, Gdn-HCl will produce substantially different effects on the conformational states of some proteins compared with those of urea.

Kaempferol-induced growth inhibition and apoptosis in A549 lung cancer cells is mediated by activation of MEK-MAPK

A vast variety of naturally occurring substances have been shown to protect against experimental carcinogenesis and an increasing amount of evidence suggests that kaempferol may have cancer chemopreventative properties. However, the precise underlying protective mechanisms are poorly understood. To elucidate these mechanisms, we challenged human lung cancer cell line A549 with kaempferol and investigated its effects upon cellular growth and signal transduction pathways. Treatment of A549 cells with kaempferol resulted in a dose- and time-dependent reduction in cell viability and DNA synthesis with the rate of apoptosis equivalent to 0.9+/-0.5, 5.2+/-1.5, 16.8+/-2.0, 25.4+/-2.6, and 37.8+/-4.5% on treatment with 0, 17.5, 35.0, 52.5, and 70.0 microM kaempferol, respectively. Concomitantly, kaempferol treatments led to a 1.2-, 2.7-, 3.3-, and 3.4-fold increase in Bax. Similar elevations were also observed in Bad which increased 1.2-, 3.3-, 3.7-, and 4.7-fold, respectively, as compared to control. Bcl-2 and Bcl-xL expression were inhibited in a dose-dependent fashion. While the Akt-1 and phosphorylated Akt-1 were inhibited, the mitogen-activated protein kinase (MAPK) was activated upon kaempferol treatment. Kaempferol induced apoptosis was associated with the cleavage of caspase-7 and poly ADP-ribose polymerase (PARP). Inhibition of MEK1/2 but not PI-3 kinase blocked kaempferol-induced cleavage of caspase-7, PARP cleavage, and apoptosis. The results suggest that inactivation of Akt-1 and alteration of Bcl-2 family of proteins are not sufficient for kaempferol to induce apoptosis and activation of MEK-MAPK is a requirement for kaempferol-induced cell death machinery in A549 cells.

Overexpression and large-scale production of recombinant L-methionine-alpha-deamino-gamma-mercaptomethane-lyase for novel anticancer therapy

The goal of the next generation of cancer chemotherapy is effective tumor-selectivity. A tumor-selective target with high therapeutic potential is the elevated methionine requirement of tumor cells relative to normal cells. We have termed the elevated requirement for methionine in tumors methionine dependence. To selectively target the methionine dependence of tumors for treatment on a large-scale preclinical and clinical basis, the L-methionine alpha-deamino-gamma-mercaptomethane-lyase (methioninase, METase) gene from Pseudomonas putida has been cloned in Escherichia coli using the polymerase chain reaction (PCR). The METase gene was then ligated into the pT7-7 overexpression plasmid containing the T7 RNA polymerase promoter and recloned in E. coli strain BL21(DE3). The pAC-1 clone was isolated by its yellow-orange color which is due to high enrichment of the pyridoxal phosphate-containing recombinant methioninase (rMETase) and distinguished rMETase-overproducer from rMETase-negative colonies. A scale-up production protocol which contained a heat step, two DEAE Sepharose FF ion-exchange, and one ActiClean Etox endotoxin-affinity chromatography columns has been established. The pAC-1 clone produces rMETase at approximately 10% of the total soluble protein and up to 1 g/liter in shake-flask culture. The protocol can produce therapeutic rMETase at the multi-gram level per batch with high yield (> 60%), high purity (> 98%), high stability, and low endotoxin. Purified rMETase is stable to lyophilization. The t1/2 of rMETase was 2 h when rMETase was administered by i.v. injection in mice. Studies of the antitumor efficacy of rMETase in vitro and in vivo on human tumors xenografted in nude mice demonstrated that all types of human tumors tested including those from lung, colon, kidney, brain, prostate, and melanoma were sensitive to rMETase. In contrast, normal cells were insensitive to rMETase in vitro and correspondingly, no toxicity was detected in vivo at the effective doses. In conclusion, the overexpression clone and large-scale production protocols for rMETase have enabled rMETase to be used as a tumor-selective therapeutic with broad indication and high promise for effective, low-toxicity human cancer therapy.

Compressive elasticity of three-dimensional nanofiber matrix directs mesenchymal stem cell differentiation to vascular cells with endothelial or smooth muscle cell markers

The importance of mesenchymal stem cells (MSC) in vascular regeneration is becoming increasingly recognized. However, few in vitro studies have been performed to identify the effects of environmental elasticity on the differentiation of MSC into vascular cell types. Electrospinning and photopolymerization techniques were used to fabricate a three-dimensional (3-D) polyethylene glycol dimethacrylate nanofiber hydrogel matrix with tunable elasticity for use as a cellular substrate. Compression testing demonstrated that the elastic modulus of the hydrated 3-D matrices ranged from 2 to 15 kPa, similar to the in vivo elasticity of the intima basement membrane and media layer. MSC seeded on rigid matrices (8-15 kPa) showed an increase in cell area compared with those seeded on soft matrices (2-5 kPa). Furthermore, the matrix elasticity guided the cells to express different vascular-specific phenotypes with high differentiation efficiency. Around 95% of MSC seeded on the 3-D matrices with an elasticity of 3 kPa showed Flk-1 endothelial markers within 24h, while only 20% of MSC seeded on the matrices with elasticity >8 kPa demonstrated Flk-1 marker. In contrast, ∼80% of MSC seeded on 3-D matrices with elasticity >8 kPa demonstrated smooth muscle α-actin marker within 24h, while fewer than 10% of MSC seeded on 3-D matrices with elasticity <5 kPa showed α-actin markers. The ability to control MSC differentiation into either endothelial or smooth muscle-like cells based purely on the local elasticity of the substrate could be a powerful tool for vascular tissue regeneration.

Fat distribution in HIV-infected patients reporting truncal enlargement quantified by whole-body magnetic resonance imaging

BACKGROUND

Antiretroviral therapy has improved the prospects for people infected with HIV, but some develop a syndrome of profound body habitus and metabolic alterations that include truncal enlargement.

OBJECTIVE

The purpose of this study was to define the body-composition changes associated with this syndrome by using techniques with the power to estimate regional body composition.

DESIGN

We compared whole-body and regional skeletal muscle and adipose tissue contents measured by magnetic resonance imaging and dual-energy X-ray absorptiometry (DXA) in 26 HIV-infected patients and 26 matched control subjects. Twelve of the HIV-infected patients had evidence of truncal enlargement.

RESULTS

HIV-infected men and women who noted truncal enlargement had similar amounts of skeletal muscle and subcutaneous adipose tissue but greater visceral adipose tissue than HIV-infected patients without truncal enlargement; these values were larger in men (P < 0.001) than in women (P = 0.08). The ratio of visceral to subcutaneous adipose tissue was greater in both men (P < 0.02) and women (P = 0.05) with truncal enlargement. Two subjects with MRI-confirmed visceral adiposity syndrome (VAS) were not taking protease inhibitors. CD4+ lymphocyte counts were higher (P < 0.001) and plasma viral burdens tended to be lower (P = 0.08) in HIV-infected patients with VAS.

CONCLUSIONS

There was significantly more visceral adipose tissue in the subgroup of HIV-infected patients with truncal enlargement than in those without this sign. VAS occurs in both men and women, is associated with higher CD4+ lymphocyte counts and lower plasma HIV viral burdens, and is not limited to those receiving protease inhibitor therapy.

Cadmium and its epigenetic effects

Cadmium (Cd) is a toxic, nonessential transition metal and contributes a health risk to humans, including various cancers and cardiovascular diseases; however, underlying molecular mechanisms remain largely unknown. Cells transmit information to the next generation via two distinct ways: genetic and epigenetic. Chemical modifications to DNA or histone that alters the structure of chromatin without change of DNA nucleotide sequence are known as epigenetics. These heritable epigenetic changes include DNA methylation, post-translational modifications of histone tails (acetylation, methylation, phosphorylation, etc), and higher order packaging of DNA around nucleosomes. Apart from DNA methyltransferases, histone modification enzymes such as histone acetyltransferase, histone deacetylase, and methyltransferase, and microRNAs (miRNAs) all involve in these epigenetic changes. Recent studies indicate that Cd is able to induce various epigenetic changes in plant and mammalian cells in vitro and in vivo. Since aberrant epigenetics plays a critical role in the development of various cancers and chronic diseases, Cd may cause the above-mentioned pathogenic risks via epigenetic mechanisms. Here we review the in vitro and in vivo evidence of epigenetic effects of Cd. The available findings indicate that epigenetics occurred in association with Cd induction of malignant transformation of cells and pathological proliferation of tissues, suggesting that epigenetic effects may play a role in Cd toxic, particularly carcinogenic effects. The future of environmental epigenomic research on Cd should include the role of epigenetics in determining long-term and late-onset health effects following Cd exposure.

cAMP-dependent regulation of proenkephalin by JunD and JunB: positive and negative effects of AP-1 proteins

We demonstrate that JunD, a component of the AP-1 transcription factor complex, activates transcription of the human proenkephalin gene in a fashion that is completely dependent upon the cAMP-dependent protein kinase, protein kinase A. Activation of proenkephalin transcription by JunD is dependent upon a previously characterized cAMP-, phorbol ester-, and Ca(2+)-inducible enhancer, and JunD is shown to bind the enhancer as a homodimer. Another component of the AP-1 transcription complex, JunB, is shown to inhibit activation mediated by JunD. As a homodimer JunB is unable to bind the enhancer; however in the presence of c-Fos, high-affinity binding is observed. Furthermore, JunD is shown to activate transcription of genes linked to both cAMP and phorbol ester response elements in a protein kinase A-dependent fashion, further blurring the distinction between these response elements. These results demonstrate that the transcriptional activity of an AP-1-related protein is regulated by the cAMP-dependent second-messenger pathway and suggest that JunD and other AP-1-related proteins may play an important role in the regulation of gene expression by cAMP-dependent intracellular signaling pathways.

Elevated levels of hepatocyte nuclear factor 3beta in mouse hepatocytes influence expression of genes involved in bile acid and glucose homeostasis

The winged helix transcription factor, hepatocyte nuclear factor-3beta (HNF-3beta), mediates the hepatocyte-specific transcription of numerous genes important for liver function. However, the in vivo role of HNF-3beta in regulating these genes remains unknown because homozygous null HNF3beta mouse embryos die in utero prior to liver formation. In order to examine the regulatory function of HNF-3beta, we created transgenic mice in which the -3-kb transthyretin promoter functions to increase hepatocyte expression of the rat HNF-3beta protein. Postnatal transgenic mice exhibit growth retardation, depletion of hepatocyte glycogen storage, and elevated levels of bile acids in serum. The retarded growth phenotype is likely due to a 20-fold increase in hepatic expression of insulin-like growth factor binding protein 1 (IGFBP-1), which results in elevated levels in serum of IGFBP-1 and limits the biological availability of IGFs required for postnatal growth. The defects in glycogen storage and serum bile acids coincide with diminished postnatal expression of hepatocyte genes involved in gluconeogenesis (phosphoenolpyruvate carboxykinase and glycogen synthase) and sinusoidal bile acid uptake (Ntcp), respectively. These changes in gene transcription may result from the disruptive effect of HNF-3beta on the hepatic expression of the endogenous mouse HNF-3alpha,-3beta, -3gamma, and -6 transcription factors. Furthermore, adult transgenic livers lack expression of the canalicular phospholipid transporter, mdr2, which is consistent with ultrastructure evidence of damage to transgenic hepatocytes and bile canaliculi. These transgenic studies represent the first in vivo demonstration that the HNF-3beta transcriptional network regulates expression of hepatocyte-specific genes required for bile acid and glucose homeostasis, as well as postnatal growth.

Lyophilization of cationic lipid-protamine-DNA (LPD) complexes

Cationic lipid-based gene delivery systems have shown promise in transfecting cells both in vitro and in vivo. However, these systems tend to form aggregates in liquid formulation during storage, which has limited their clinical applications. As a result, lyophilization of these systems has recently become a subject of increasing interest. In this paper, lyophilization of LPD, a novel cationic lipid-based gene delivery system, was studied. Both particle size and transfection efficiency could be preserved in the presence of sufficient amount of appropriate lyoprotectant. A series of monosaccharides and disaccharides, including dextrose, galactose, mannose, lactose, maltose, sucrose and trehalose, were evaluated for their lyoprotective effect and disaccharides showed more superior protection to monosaccharides. The effect of different freezing protocols for lyophilization was also evaluated and no significant difference was found. However, for freeze-thawing, fast freezing caused less aggregation. Finally, nonlyophilized LPD and LPD lyophilized with 10% sucrose were stored at different temperatures and their stability was followed for eight weeks. Lyophilized LPD could be stored at room temperature without significant change in particle size or loss of transfection efficiency.

Non-C2-Symmetric Chiral-at-Ruthenium Catalyst for Highly Efficient Enantioselective Intramolecular C(sp3)-H Amidation

A new class of chiral ruthenium catalysts is introduced in which ruthenium is cyclometalated by two 7-methyl-1,7-phenanthrolinium heterocycles, resulting in chelating pyridylidene remote N-heterocyclic carbene ligands (rNHCs). The overall chirality results from a stereogenic metal center featuring either a Λ or Δ absolute configuration. This work features the importance of the relative metal-centered stereochemistry. Only the non-C₂-symmetric chiral-at-ruthenium complexes display unprecedented catalytic activity for the intramolecular C(sp³)-H amidation of 1,4,2-dioxazol-5-ones to provide chiral γ-lactams with up to 99:1 er and catalyst loadings down to 0.005 mol % (up to 11 200 TON), while the C₂-symmetric diastereomer favors an undesired Curtius-type rearrangement. DFT calculations elucidate the origins of the superior C-H amidation reactivity displayed by the non-C₂-symmetric catalysts compared to related C₂-symmetric counterparts.

A novel method for diabetes diagnosis based on electronic nose

A novel non-invasive method for diabetes diagnosis based on an electronic nose is proposed in this paper. The principles of the method and results of clinical experiments are presented. These results show the convenience, painlessness and non-invasiveness of the method.