Controlled establishment of advanced local high-entropy NiCoMnFe-based layered double hydroxide for zinc batteries and low-temperature supercapacitors

The development of high-performance electrodes is essential for improving the charge storage performance of rechargeable devices. In this study, local high-entropy C, N co-doped NiCoMnFe-based layered double hydroxide (C/N-NiCoMnFe-LDH, C/N-NCMF) were designed using a novel method. Multi-component synergistic effects can dramatically modulate the surface electron density, crystalline structure, and band-gap of the electrode. Thus, the electrical conductivity, electron transfer, and affinity for the electrolyte can be optimized. Additionally, the C/N-NCMF yielded a high specific capacitance (1454F·g-1) at 1 A·g-1. The electrode also exhibited excellent cycling stability, with 62 % capacitance retention after 5000 cycles. Moreover, the assembled Zn||C/N-NCMF battery and the C/N-NCMF//AC hybrid supercapacitor yielded excellent energy densities of 63.1 and 35.4 Wh·kg-1 at power densities of 1000 and 825 W·kg-1, and superior cycling performance with 69 % and 88.7 % capacitance retention after 1000 and 30,000 cycles, respectively. Furthermore, the electrode maintained high electrochemical activity and stability and ensured high energy density, power density, and cycling stability of the rechargeable devices even at a low temperature (-20 °C). This study paves a new pathway for regulating the electrochemical performance of LDH-based electrodes.

Evolution of High-Index Facets Pt Nanocrystals Induced by N-Defective Sites in the Integrated Electrode for Enhanced Methanol Oxidation

Highly efficient and durable Pt electrocatalysts are the key to boost the performance of fuel cells. The high-index facets (HIF) Pt nanocrystals are regarded as excellent catalytic activity and stability catalysts. However, nucleation, growth and evolution of high-index facets Pt nanocrystals induced by defective sites is still a challenge. In this work, tetrahexahedron (THH) and hexactahedron (HOH) Pt nanocrystals are synthesized, which are loaded on the nitrogen-doped reduced graphene oxide (N-rGO) support of the integrated electrodes by the square wave pulse method. Experimental investigations and density functional theory (DFT) calculations are conducted to analyze the growth and evolution mechanism of HIF Pt nanocrystals on the graphene-derived carbon supports. It shows that the H adsorption on the N-rGO/CFP support can induce evolution of Pt nanocrystals. Moreover, the N-defective sites on the surface of N-rGO can lead to a slower growth of Pt nanocrystals than that on the surface of reduced graphene oxide (rGO). Pt/N-rGO/CFP (20 min) shows the highest specific activity in methanol oxidation, which is 1.5 times higher than that of commercial Pt/C. This research paves the way on the design and synthesis of HIF Pt nanocrystal using graphene-derived carbon materials as substrates in the future.

Electrochemical Performance of Corn Waste Derived Carbon Electrodes Based on the Intrinsic Biomass Properties

The exploration of cost-effective and sustainable biomass-derived carbon materials as electrodes for energy conversion and storage has gained extensive attention in recent research studies. However, the selection of the biomass and the electrochemical performance regulation of the derived biochar, as well as their interrelationship still remain challenging for practical application. Herein, corn wastes with high carbon content (>40%), corn cob and corn silk, were selected as precursors for the preparation of high value-added and high yield carbon materials via a modified synthetic process. Uniquely, this work put emphasis on the theoretical and experimental investigations of how the biomass properties influence the composition and nanostructure regulation, the electrolyte ion adsorption free energy, and the electrical conductivity of the derived carbon materials as well as their electrochemical performance optimization. Owing to the favorable specific surface area, the hierarchical porous structure, and the diverse elemental distribution, corn cob and corn silk derived carbon materials (CBC and SBC) present great potential as promising electrodes for alkaline aqueous zinc batteries and supercapacitors. The assembled CBC//Zn and SBC//Zn zinc batteries deliver high energy densities of 63.0 Wh kg^-1 and 39.1 Wh kg^-1 at a power density of 575 W kg^-1, with excellent cycling performance of 91.1% and 84.3% capacitance retention after 10,000 cycles. As for the assembled symmetric supercapacitors, high energy densities of 14.9 Wh kg^-1 and 13.6 Wh kg^-1, and superior long-term cycling stability of 99.3% and 96.6% capacitance retention after 20,000 cycles could be achieved. This study highlights the advantages of utilizing corn cob and corn silk as carbon sources on the designed synthesis of carbon electrodes, and presents a meaningful perspective in the investigation of biomass-derived carbon materials and their potential applications in rechargeable devices.

Anti-inflammatory activity of different isolated sites of Chloranthus serratus in complete Freund's adjuvant-induced arthritic rats

Chloranthus serratus is a traditional Chinese medicine for treating arthritis and bruises. The aim of the present study was to investigate the anti-arthritic activities and possible associated mechanisms of different isolated sites of Chloranthus serratus (DISC) in adjuvant-induced arthritis (AA) rats. The therapeutic effects of the extracts were assessed through changes in body weights, swelling rates, arthritis indexes (AI) and organ indexes. The levels of nitric oxide (NO), malondialdehyde and superoxide dismutase were determined using one-step method, TBA method and hydroxylamine method, respectively; the levels of TNF-α, IL-1β, IL-6, prostaglandin E2, macrophage inhibitor factor-1, VEGF, immunoglobulin (Ig) G, IgM and IFN-γ in serum were determined using ELISA. Pathological changes and positive expression of VEGF in the ankle joints were investigated using hematoxylin-eosin staining and immunohistochemical staining, respectively. DISC treatment increased the weight gains and thymus indexes, and decreased the swelling rates, spleen indexes and AI in AA rats. The water isolated site (WA) and ethyl acetate isolated site (EA) significantly reversed complete Freund's adjuvant (CFA)-induced changes in the levels of NO, IL-6, TNF-α, IgG and IFN-γ, while the n-butanol isolated site (NB) only reversed the changes in IL-6 and IgG contents. Some changes in the chloroform isolated site group showed the same trend as those in the model group. The extracts relieved synovial hyperplasia, inflammatory cell infiltration and articular surface defects, and reduced the positive expression rate of VEGF in the synovial tissues of the AA rats to varying degrees. The WA exhibited the most marked effects, followed by the EA and NB, indicating that WA had optimal therapeutic effects on CFA-induced arthritic rats, which may be mediated by the oxidative stress and inhibition of inflammatory factors. C. serratus may serve as a potential candidate for the treatment of rheumatoid arthritis.

Fabrication of a near-infrared excitation surface molecular imprinting ratiometric fluorescent probe for sensitive and rapid detecting perfluorooctane sulfonate in complex matrix

Construction of fluorescent probe for highly sensitive and selective detection of perfluorooctane sulfonate (PFOS) in water and biological samples is a very important strategy in related pollutant monitoring and environmental health risk appraisal. To overcome the drawback of low sensitivity caused by high-back ground signal of the conventional sensor, a molecularly imprinted near-infrared excitation ratiometric fluorescent probe was constructed and employed to determine PFOS. The sensing process was achieved through the selectively recognition of specific cavities in the probe surface with analyte, accompanied by fluorescence quenching due to the photoinduced electron transfer effect between upconversion materials and PFOS. Under optimized experimental conditions, the fluorescence quenching efficiency of the probe has good linearity against the concentrations of PFOS response divided into two segments within linear ranges of 0.001-0.1 nmol/L and 0.1-1 nmol/L, respectively, with low detection limit of 1 pmol/L. Selective experiment results indicate that the C-F chain length plays a dominant role in molecular recognition and high sensitively detection. The fabricated probe shows well detection performance in a wide pH range. Furthermore, real samples analyses indicate that such an efficient fluorescent probe has potentials in PFOS determination in surface water, human serum and egg extract sample analyses.

Oxidative stress-mediated hepatotoxicity in rats induced by ethanol extracts of different parts of Chloranthus serratus

CONTEXT

Chloranthus serratus (Thunb.) Roem. et Schult. (Chloranthaceae) is an herb widely used as a folk medicine treating inflammatory diseases, although it is toxic.

OBJECTIVE

To investigate hepatotoxicity and related mechanisms induced by ethanol extracts of different parts of C. serratus in rats.

MATERIALS AND METHODS

Sprague Dawley rats were divided into control (Con), ethanol extract of roots (ER), stems (ES), and leaves (EL) groups, and acute oral toxicity studies were conducted. The rats received doses of 4.14, 3.20, and 1.16 g/kg/d extracts for 14 days, respectively. Liver index, liver function and oxidative stress biomarkers, liver pathology, ultrastructure, TNF-α, ICAM-1, and Nrf2/HO-1 proteins expression levels were determined.

RESULTS

The LD₅₀ of ER, ES, and EL were higher than 10.35, 8.05, and 2.90 g/kg/p.o., respectively. The liver indexes in the extract groups increased significantly. EL dramatically increased TP, GLB, AST, ALT, ALP, TBA, MDA, ICAM-1, and TNF-α levels (p < 0.01), and induced the most obvious pathological and ultrastructural changes. ES and EL obviously decreased the T-SOD, GSH, CAT, and CHOL levels. Nrf2 and HO-1 proteins expression was reduced significantly in ES (0.77 ± 0.06, 2.33 ± 0.20) and EL (0.23 ± 0.04, 2.14 ± 0.16) groups, and reduced slightly in ER (1.08 ± 0.10; 3.39 ± 0.21) group.

DISCUSSION AND CONCLUSION

ES and EL induce stronger hepatotoxicity than ER through oxidative stress and the Nrf2/HO-1 pathway, and the root is a better medicinal part, which provides a basis for clinical research, safe applications, and reasonable development of C. serratus.

Toxin-antitoxin operon kacAT of Klebsiella pneumoniae is regulated by conditional cooperativity via a W-shaped KacA-KacT complex

Bacterial toxin–antitoxin pairs play important roles in bacterial multidrug tolerance. Gcn5-related N-acetyltransferase (GNAT) toxins inhibit translation by acetylation of aminoacyl-tRNAs and are counteracted by direct contacts with cognate ribbon–helix–helix (RHH) antitoxins. Our previous analysis showed that the GNAT toxin KacT and RHH antitoxin KacA of Klebsiella pneumoniae form a heterohexamer in solution and that the complex interacts with the cognate promoter DNA, resulting in negative autoregulation of kacAT transcription. Here, we present the crystal structure of DNA-bound KacAT complex at 2.2 Å resolution. The crystal structure revealed the formation of a unique heterohexamer, KacT–KacA₂–KacA₂–KacT. The direct interaction of KacA and KacT involves a unique W-shaped structure with the two KacT molecules at opposite ends. Inhibition of KacT is achieved by the binding of four KacA proteins that preclude the formation of an active KacT dimer. The kacAT operon is auto-regulated and we present an experimentally supported molecular model proposing that the KacT:KacA ratio controls kacAT transcription by conditional cooperativity. These results yield a profound understanding of how transcription GNAT–RHH pairs are regulated.

Novel mutations and expression changes of acetyl-coenzyme A carboxylase are associated with spirotetramat resistance in Aphis gossypii Glover

Acetyl-coenzyme A carboxylase (ACC) catalyses the carboxylation of acetyl-coenzyme A (acetyl-CoA) to produce malonyl-CoA during the de novo synthesis of fatty acids. Spirotetramat, an inhibitor of ACC, is widely used to control a range of sucking insects, including the Aphis gossypii. In the present study, Reverse transcription quantitative real-time PCR (RT-qPCR) results demonstrated that ACC was significantly overexpressed in a laboratory-selected spirotetramat-resistant strain compared with the susceptible strain. ACC RNA interference significantly suppressed fecundity and led to cuticle formation deficiencies in resistant adults and nymphs compared with the control. The full-length ACC gene was sequenced from both resistant and susceptible cotton aphids, and a strong association was found between spirotetramat resistance and 14 amino acid substitutions in the biotin carboxylase domain and carboxyl transferase domain of the ACC gene. Furthermore, ACC activity was higher in resistant aphids than in the susceptible strain, and ACC in the resistant aphids exhibited significant insensitivity to spirotetramat and spirotetramat-enol. The results indicate that the overexpressed insensitive (mutated) ACC target played an important role in the high levels of spirotetramat resistance observed here. This association of amino acid substitution with resistance is the first report of a potential target site mechanism affecting spirotetramat in the cotton aphid.

Over-expression of CYP6A2 is associated with spirotetramat resistance and cross-resistance in the resistant strain of Aphis gossypii Glover

A laboratory-selected spirotetramat-resistant strain (SR) of cotton aphid developed 579-fold and 15-fold resistance to spirotetramat in adult aphids and 3rd instar nymphs, respectively, compared with a susceptible strain (SS) [26]. The SR strain developed high-level cross-resistance to alpha-cypermethrin and bifenthrin and very low or no cross-resistance to the other tested insecticides. Synergist piperonyl butoxide (PBO) dramatically increased the toxicity of spirotetramat and alpha-cypermethrin in the resistant strain. RT-qPCR results demonstrated that the transcriptional levels of CYP6A2 increased significantly in the SR strain compared with the SS strain, which was consistent with the transcriptome results [30]. The depletion of CYP6A2 transcripts by RNAi also significantly increased the sensitivity of the resistant aphid to spirotetramat and alpha-cypermethrin. These results indicate the possible involvement of CYP6A2 in spirotetramat resistance and alpha-cypermethrin cross-resistance in the cotton aphid. These together with other cross-resistance results have implications for the successful implementation of resistance management strategies for Aphis gossypii.

Spirotetramat resistance adaption analysis of Aphis gossypii Glover by transcriptomic survey

A resistant strain of the cotton aphid (SR) developed 441.26-fold and 11.97-fold resistance to spirotetramat for adult aphids and nymphs, respectively, compared with the susceptible (SS) strain. Solexa sequencing technology was employed to identify differentially expressed genes (DEGs) in the spirotetramat-resistant cotton aphid. Respective totals of 22,430,522 and 21,317,732 clean reads were obtained from SR and SS cDNA libraries and assembled into 35,222 non-redundant (Nr) consensus sequences. A total of 14,913, 9,220, 7,922, 4,314 and 4,686 sequences were annotated using Nr, Swiss-Prot, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and Clusters of Orthologous Groups (COG), respectively. Compared with the SS strain, the SR strain had 1287 significantly changed unigenes, of which 130 genes were up-regulated and 1157 genes were down-regulated (P ≤ 0.001). Among these genes, 440 unigenes were annotated, consisting of 114 up-regulated and 326 down-regulated genes. The expression levels of heat shock protein 70 (Hsp70) and UDP-glucuronosyltransferase were significantly up-regulated in the SR strain compared to the SS strain. The genes encoding cuticle proteins, salivary glue protein, fibroin heavy chain, energy ATP synthase, and cytochrome c oxidase were dramatically decreased. Among the DEGs, cytochrome P450 6A2 (c20965.graph_c0) was the only P450 gene up-regulated in the SR strain. The expression levels of 10 DEGs were confirmed by real-time qPCR, and the trends in gene expression observed by qPCR matched those of the Solexa expression profiles. The acetyl-CoA carboxylase (ACC) genes in the SR and SS libraries both contain four single nucleotide polymorphisms (SNPs), with three common SNPs: 1227 (C/T), 1811 (A/T: F/Y) and 3759 (C/T); however, 7540 (A/T) and 108 (G/A) occurred solely in the SS and SR strains, respectively.

Patient characteristics and treatment patterns for patients with benign prostatic hyperplasia, erectile dysfunction or co-occurring benign prostatic hyperplasia and erectile dysfunction in general practices in the UK: a retrospective observational study

AIMS

The aim of this study was to assess patient characteristics, medication treatment patterns and healthcare resource utilization among men with existing erectile dysfunction (ED) or benign prostatic hyperplasia (BPH), who are newly diagnosed with the second condition (BPH or ED) compared with those with only one condition.

METHODS

This retrospective cohort study utilized the Clinical Practice Research Datalink. Males, aged 40 years or older, newly diagnosed with ED or symptomatic BPH between 1 June 2010 and 31 May 2011, were selected. Patient demographics, existing comorbidities and baseline medication use were analysed. Treatments initiated for the incident condition and treatment patterns were reported at 6, 12, 18 and 24-months postdiagnosis. Referrals to urologists and visits to general practitioners were reported around diagnosis and during follow-up.

RESULTS

This study included 11,501 incident patients with BPH, of which 23% had a prior ED diagnosis and 9,734 incident patients with ED, of which 17% had a prior BPH diagnosis. The average age at diagnosis of BPH was similar across both cohorts. Among incident patients with ED, those with prior diagnosis of BPH were diagnosed at an older average age (65 ± 9.2 years) compared to those without BPH (57 ± 9.1 years). The majority of patients in both incident BPH cohorts (62.9-65.5%) were prescribed alpha-blockers as initial treatment. The majority of patients in both incident ED cohorts (49.6-51.6%) were prescribed sildenafil as initial treatment followed by tadalafil (24.3-26.0%). At 12 months, 50% of incident patients with BPH and 80% of patients with ED had discontinued the therapy initiated.

CONCLUSION

This study found that in the UK, patients with co-occurring BPH and ED when newly diagnosed with the second condition initiated the same treatments as those without prior ED or BPH. During the first year, treatment patterns including discontinuation were comparable in the groups with one of the conditions and co-occurring BPH and ED.

Transformation of cellulose and its derived carbohydrates into formic and lactic acids catalyzed by vanadyl cations

The transformation of cellulose or cellulose-derived carbohydrates into platform chemicals is the key to establish biomass-based sustainable chemical processes. The systems able to catalyze the conversion of cellulose into key chemicals in water without the consumption of hydrogen are limited. We report that simple vanadyl (VO(2+)) cations catalyze the conversions of cellulose and its monomer, glucose, into lactic acid and formic acid in water. We have discovered an interesting shift of the major product from formic acid to lactic acid on switching the reaction atmosphere from oxygen to nitrogen. Our studies suggest that VO(2+) catalyzes the isomerization of glucose to fructose, the retro-aldol fragmentation of fructose to two trioses, and the isomerization of trioses, which leads to the formation of lactic acid under anaerobic conditions. The oxidative cleavage of C-C bonds in the intermediates caused by the redox conversion of VO2(+)/VO(2+) under aerobic conditions results in formic acid and CO2. We demonstrate that the addition of an alcohol suppresses the formation of CO2 and enhances the formic acid yield significantly to 70-75 %.

[Increasing number and improved survival of patients with hepatocellular carcinoma from 1988 to 2007: data of a German university clinic]

BACKGROUND AND OBJECTIVES

Hepatocellular carcinoma (HCC) ranks sixth regarding prevalence and third regarding mortality among malignant tumours worldwide. The aim of the present study was to determine changes of clinical-epidemiological parameters and survival rates during two decades.

PATIENTS AND METHODS

A total of 441 consecutive patients with HCC admitted to the University Clinic Düsseldorf between January 1988 and December 2007 were included. For comparison, this time period was divided into two decades (1988 - 1997 and 1998 - 2007).

RESULTS

The number of newly diagnosed HCCs has tripled in the years 1998 - 2007 compared to the years 1988 - 1997. HCV-associated HCCs increased from 28 % in the years 1988 - 1997 to 38 % (p < 0.05) in the years 1998 - 2007. Tumour size, Okuda and BCLC stages decreased during the observation period (both p < 0.001 and p < 0.05). Median overall survival improved during the observation period from 6 [95 % CI: 4.83 - 7.17] to 9 months ]95 % CI: 7.31 - 10.69]; p < 0.0001) as did the 1-year and 5-year survival rates from 22 % to 42 % (p < 0.019) and from 0 % to 9 % (p < 0.001), respectively. The proportion of treated patients compared to patients with best supportive care as well as the proportion of patients receiving a multimodal therapy compared to patients with a single treatment regimen increased in the second decade (55 % vs. 79 %: p < 0.005; 5.4 % vs. 23 %: p < 0.0001). Multimodal therapy was an independent predictor for prolonged survival in a multivariate analysis including Child-Pugh score, BCLC stage, tumour size, and gender (odds ratio 2,77; 95 % CI: 1.44 - 5.31).

CONCLUSION

Improved screening as well as broader and improved treatment options may have contributed to the increasing survival rates.

Fe(3)O(4)-Au and Fe(2)O(3)-Au Hybrid Nanorods: Layer-by-Layer Assembly Synthesis and Their Magnetic and Optical Properties

A layer-by-layer technique has been developed to synthesize FeOOH-Au hybrid nanorods that can be transformed into Fe(2)O(3)-Au and Fe(3)O(4)-Au hybrid nanorods via controllable annealing process. The homogenous deposition of Au nanoparticles onto the surface of FeOOH nanorods can be attributed to the strong electrostatic attraction between metal ions and polyelectrolyte-modified FeOOH nanorods. The annealing atmosphere controls the phase transformation from FeOOH-Au to Fe(3)O(4)-Au and α-Fe(2)O(3)-Au. Moreover, the magnetic and optical properties of as-synthesized Fe(2)O(3)-Au and Fe(3)O(4)-Au hybrid nanorods have been investigated.

Survivin is a key factor in the differential susceptibility of gastric endothelial and epithelial cells to alcohol-induced injury

We previously demonstrated that the anti-apoptosis protein, survivin, plays a protective role against alcohol-induced gastric injury. Since the endothelium is a primary target of alcohol-induced gastric damage, we investigated whether survivin expression is a key factor in the greater susceptibility of gastric endothelial vs. epithelial cells to alcohol-induced injury. Here, we demonstrate that rat gastric epithelial cells (RGM1 cells, an epithelial cell line derived from normal rat gastric mucosa) expressed 7.5-fold greater survivin protein levels vs. rat gastric endothelial cells. Survivin expression correlated with resistance of gastric epithelial vs. endothelial cells to both alcohol-induced cell damage and alcohol-induced apoptosis. Suppression of survivin protein expression levels using siRNA rendered the gastric epithelial cells as susceptible to both alcohol-induced cell damage and apoptosis as the gastric endothelial cells. Conversely, forced overexpression of survivin by transient transfection rendered gastric endothelial cells as resistant to both alcohol-induced cell damage and apoptosis as mock-transfected gastric epithelial cells. Moreover, overexpression of a threonine-34 to glutamate phosphorylation mimic mutant survivin construct rendered gastric endothelial cells significantly more resistant to alcohol-induced damage and apoptosis vs. mock-transfected gastric epithelial cells. These findings indicate that disparate survivin expression levels can explain the discrepancy between gastric epithelial and endothelial cell susceptibility to alcohol-induced injury; and, that a negative charge at amino acid residue 34 on survivin, such as that which naturally occurs by phosphorylation of threonine-34, enhances its property in conferring gastric mucosal protection.

Hydrothermal synthesis and photoluminescence of Eu(2-x)Sm(x)Sn2O7 (x = 0-2.0) nanophosphors

Eu(2-x)Sm(x)Sn2O7 (x = 0, 0.1, 0.5, 1.0, 1.5, and 2.0) solid solutions were successfully synthesized by a simple, mild hydrothermal process. The crystal structure, particle size, and chemical composition of the solid solutions were characterized by X-ray diffraction, transmission electron microscopy, and energy dispersive X-ray spectroscopy. X-ray diffraction patterns and transmission electron microscopy images reveal that all the products were cubic pyrochlore-type Eu(2-x)Sm(x)Sn2O7 nanocrystals with the diameter of approximately 20 nm. Due to efficient energy transfer from Sm3+ to Eu3+, the Eu(2-x)Sm(x)Sn2O7 (x = 0.1, 0.5, 1.0, and 1.5) nanocrystals exhibited strong 5D0 --> 7F1 photoluminescence emission of Eu3+. The dominant 5D0 --> 7F1 transition revealed good monochromaticity and low distortion of the Eu(2-x)Sm(x)Sn2O7 nanophosphors.

Functional magnetic stimulation for conditioning of expiratory muscles in patients with spinal cord injury

OBJECTIVE

To evaluate the effectiveness of functional magnetic stimulation (FMS) in conditioning expiratory muscles patients with spinal cord injury (SCI).

DESIGN

A prospective before-after trial.

SETTING

The Functional Magnetic Stimulation Laboratory of the SCI Health Care Group, VA Long Beach Health Care System, and the Spinal Cord Injury Services, Department of Veterans Affairs, Palo Alto Health Care System.

PARTICIPANTS

Eight men with tetraplegia.

INTERVENTION

Expiratory muscle training was achieved by placing a magnetic stimulator with a round magnetic coil along subjects' lower thoracic spine.

MAIN OUTCOME MEASURES

Measures taken were the maximal expired pressure at total lung capacity (MEP-TLC) and at functional residual capacity (MEP-FRC), expiratory reserve volume (ERV), and the forced expiratory flow rate at TLC (FEF-TLC) and at FRC (FEF-FRC) by subjects' voluntary maximal efforts.

RESULTS

After 4 weeks of conditioning, the mean +/- standard error of the mean values were: MEP-TLC, 55.3 +/- 8.6cmH(2)O; MEP-FRC, 29.6 +/- 5.6cmH(2)O; ERV,.57 +/-.08L; FEF-TLC, 4.3 +/- 0.5L/s; and FEF-FRC, 1.9 +/- 0.2L/s. These values correspond to, respectively, 129%, 137%, 162%, 109%, and 127% of pre-FMS conditioning values. When FMS was discontinued for 2 weeks, the MEP-TLC returned to its pre-FMS training value.

CONCLUSION

A 4-week protocol of FMS of the expiratory muscles improves voluntary expiratory muscle strength significantly, indicating that FMS can be a noninvasive therapeutic technology in respiratory muscle training for persons with tetraplegia.

Induction of the ATP-sensitive potassium (uK(ATP)-1) channel by endotoxemia

The effect of sepsis on the ubiquitously expressed ATP-sensitive potassium (uK(ATP)-1) channel expression was measured in Sprague-Dawley rat diaphragms. Rats were treated with either 0.5 ml saline or 20 mg/Kg E. coli lipopolysaccharides and sacrificed at 3, 6, 12, 24, or 48 h later. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis showed that channel mRNA expression was increased at 3 h and continued to rise up to 48 h. Western blotting analysis showed a approximately 9-fold increase in channel protein expression 24 h after sepsis. Our results demonstrate that sepsis upregulates the uK(ATP)-1 channel.

Expression of myosin heavy-chain isoforms in the respiratory muscles following inspiratory resistive breathing

We investigated the effect of inspiratory resistive breathing (IRB) on the expression of the genes encoding fast and slow isoforms of myosin heavy chain (MyHC) in respiratory muscles. Eleven mongrel dogs were studied for baseline MyHC messenger RNA (mRNA) expression, seven of which were also used to study the effects of IRB. For this latter objective, awake and spontaneously breathing animals were subjected to 2 h of IRB (80 cm H(2)O/L/s) per day for four consecutive days. mRNA expression was assessed in the diaphragm, external intercostal muscle, and a limb muscle, using both slot- blot and in situ hybridizations with isoform-specific probes. A current semiquantitative scoring method (from 0 to 4) was used to quantify the in situ mRNA expression levels, and slot-blot data were analyzed with densitometry. Prior to IRB, slow- and fast-MyHC mRNA expression was moderate, similar, and homogeneous throughout the different regions of the diaphragm, with scores of 1.50 +/- 0.54 (mean +/- SD) for slow and 2.13 +/- 0.35 for fast mRNAs in the costal region of the diaphragm, and of 1.81 +/- 0.37 for slow and 2. 13 +/- 0.64 for fast mRNAs in the crural region of the diaphragm. Although expression of fast-MyHC mRNA remained unchanged after IRB, the relative expression of the mRNA for the slow isoform increased in costal (+30%), crural (+12%), and external intercostal (+27%) muscles. MyHC mRNA expression did not change in limb muscles. We conclude that breathing with a moderate inspiratory resistance for a short period induces the expression of slow MyHC in respiratory muscles.

[Software development of multi-element transient signal acquisition and processing with multi-channel ICP-AES]

A software for multi-channel ICP-AES multi-element transient signal acquisition and processing were developed in this paper. It has been successfully applied to signal acquisition and processing in many transient introduction techniques on-line hyphenated with multi-channel ICP-AES.

Influence of tension time on muscle fiber sarcolemmal injury in rat diaphragm

We hypothesized that the amount of sarcolemmal injury is directly related to the total tension time (TT(tot)), calculated as mean tension x total stimulation time. Diaphragm strips from Sprague-Dawley rats were superfused at optimal muscle length with Krebs containing procion orange to identify sarcolemmal injury. TT(tot) was induced by stimulation with 100 Hz for 3 min at duty cycles of 0.02, 0.15, 0.3, and 0.6, or with continuous contractions at 0.2, 0.4, 0.6, and 1.0 of maximal tension. A significant positive correlation between TT(tot) and the percentage of fibers with injured sarcolemma (r(2) = 0.63, P < 0.05) is seen. Stimulation (at 100 Hz, duty cycle = 1) resulted in fast fatigue with low injury, likely caused by altered membrane conductivity. Stimulations inducing the largest injury are those showing progressive force loss and high TT(tot), where injury may be due to activation of membrane degradative enzymes. The maximal tension measured at 20 min poststimulation was inversely related to the number of fibers injured, suggesting loss of force is caused by cellular injury.

Dystonin-deficient mice exhibit an intrinsic muscle weakness and an instability of skeletal muscle cytoarchitecture

Dystonia musculorum (dt) was originally described as a hereditary sensory neurodegeneration syndrome of the mouse. The gene defective in dt encodes a cytoskeletal linker protein, dystonin, that is essential for maintaining neuronal cytoskeletal integrity. In addition to the nervous system, dystonin is expressed in a variety of other tissues, including muscle. We now show that dystonin cross-links actin and desmin filaments and that its levels are increased during myogenesis, coinciding with the progressive reorganization of the intermediate filament network. A disorganization of cytoarchitecture in skeletal muscle from dt/dt mice was observed in ultrastructural studies. Myoblasts from dt/dt mice fused to form myotubes in culture; however, terminally differentiated myotubes contained incompletely assembled myofibrils. Another feature observed in dt/dt myotubes in culture and in skeletal muscle in situ was an accumulation and abnormal distribution of mitochondria. The diaphragm muscle from dt/dt mice was weak in isometric contractility measurements in vitro and was susceptible to contraction-induced sarcolemmal damage. Altogether, our data indicate that dystonin is a cross-linker of actin and desmin filaments in muscle and that it is essential for establishing and maintaining proper cytoarchitecture in mature muscle.

Ontogenesis of nitric oxide synthases in the ventilatory muscles

Nitric oxide (NO) acts as an endogenous mediator in mature skeletal muscle. In this study, we investigated the regulation of the endothelial (eNOS) and neuronal (nNOS) isoforms of nitric oxide synthase (NOS) in skeletal-muscle development (rat diaphragm). Muscle NOS activity, nNOS and eNOS protein, and mRNA expressions were markedly increased during the late gestational and early postnatal periods. Expression of both isoforms, however, declined progressively thereafter. Similarly, argininosuccinate lyase and argininosuccinate synthetase, both involved in the recycling of L-citrulline to L-arginine, were expressed at high levels in rat embryonic and neonatal diaphragms, with gradual reduction in their expression during late postnatal development. Immunostaining revealed extensive nNOS expression at the sarcolemma in neonatal and mature diaphragms, whereas eNOS expression was limited to the endothelium. Both neonatal and adult diaphragms expressed an alternatively spliced nNOS isoform with an insert of 34 amino acids between exons 16 and 17. In vitro-generated muscle force rose significantly after NOS inhibition in both neonatal and adult diaphragms, but the magnitude of force augmentation was larger in adult than in neonatal diaphragm. These results indicate that constitutive NOS isoforms are developmentally regulated in skeletal muscles, suggesting multiple roles for NO in developing and mature skeletal-muscle fibers.

Diaphragm muscle fiber injury after inspiratory resistive breathing

Five awake previously tracheotomized mongrel dogs were challenged with inspiratory resistive breathing (IRB). The mean peak tracheal pressure = -35.4 +/- 1.1 cmH2O, ETCO2 = 39.8 +/- 1.5 mmHg was sustained for 2 h/d over 4 consecutive d. On the fourth day, following IRB, the dogs were placed under general anaesthesia, and the diaphragm was perfused via the internal mammary artery with a low molecular weight fluorescent tracer (Procion orange, FW = 631), to which normal muscle fibers are impermeable. Muscle fiber membrane damage was identified on tissue sections by using fluorescent microscopy showing the presence of the tracer in the cytoplasm. Four dogs undergoing the same protocol (except IRB) served as control. The dye was seen in 7.6 +/- 2.6% and in 0.3 +/- 0.1% of fibers in the IRB and control groups, respectively (p < 0.05). Via ATPase staining, it was found that fibers of type I were predominantly affected as compared to type II (p < 0.05). In addition, an increased area fraction of fibers demonstrating sarcomere disruption was found after IRB (2.4 +/- 0.5%) compared to pre-IRB (0.4 +/- 0.1%; p < 0.05). We conclude that resistive breathing of a magnitude similar to that seen in some respiratory diseases, or used in respiratory muscle training programs induces muscle membrane and sarcomere injury.

[Dental lamina as presumptive source of odontogenic cyst]

The possibility of the dental lamina as a source of odontogenic cyst was investigated. The mandibular first molar tooth germs with the dental lamina and surface oral epithelium were cut from 17.5-day-old C3H mouse embryos. The following 5 kinds of grafts were prepared: (I) recombinant of the dental lamina and dental papilla, (II) dental lamina, (III) dental papilla, (IV) recombinant of the oral epithelium and dental papilla and (V) oral epithelium. After the renal subcapsular transplantation to the 3-month-old syngenic male mice, each graft was harvested at timed sequences from 2 to 24 weeks and was examined histopathologically. The recombinant of the dental lamina and dental papilla (1) grew into a cyst lined by para-keratinized stratified squamous epithelium. The cyst enlarged gradually and might be compared to the odontogenic keratocyst of the human being. The recombinant of the oral epithelium and dental papilla (IV) and the oral epithelium (V) developed into a cyst lined by orthokeratinized stratified squamous epithelium which differed from the epithelium seen in Experiment (I). The dental papilla (III) grew to be a bone tissue while nothing developed from the dental lamina (II). These results suggest that the dental lamina is one of the sources of the odontogenic keratocyst and the dental papilla plays an important role in its histogenesis.