Determination of hydrogen gas by 1,4-bis(phenylethynyl)benzene hydrogenation coupled with gas chromatography-mass spectrometry

Knowing the H2 concentration released from polymer materials is essential to understand the degradation degree of polymer materials. In this study, a novel strategy of 1,4-bis(phenylethynyl)benzene (DEB) hydrogenation in combination with gas chromatography - mass spectrometry (GC-MS) determination of hydrogen gas (H2) was developed. In this strategy, DEB was utilized to react with H2 for establishing the quantitative analysis method of H2. A H2 analysis platform that could accurately control H2 concentration was designed and fabricated to be used to establish the quantitative method of H2. The linear regression curve was established between the H2 standard and the MS signal of the reaction products on GC-MS. Finally, the H2 released from polyethylene under gamma radiation was detected by this method. This method could be a powerful auxiliary tool for studying the content changes of H2.

Resource allocation of rural institutional elderly care in China's new era: spatial-temporal differences and adaptation development

OBJECTIVES

In the new era of China, to ensure that rural residents can get the corresponding institutional elderly services equally, it is necessary to investigate the current situation of resource allocation of rural institutional elderly care and make corresponding adaptation suggestions.

STUDY DESIGN

This research discusses the characteristics and evolution pattern of rural aging, the resource allocation of rural elderly care institutions, and the adaptation degree of rural institutional elderly care resource and aging.

METHODS

The research methodology consists of the following stages: entropy-based Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS), kernel density estimation, coupling coordination, spatial autocorrelation, and Theil index decomposition.

RESULTS

The degree of aging in rural areas of China is rising, and the whole population has entered a moderate aging society, showing the spatial characteristics of 'high in the east and low in the west'. The resource allocation of rural institutional elderly care in China is at a low level, and the absolute differences among provinces tend to reduce over time, and the overall resource allocation level tends to decline. The provinces that were in the mismatched adaptation relationship in the early stage have improved; however, the number of provinces with mismatched adaptability has continued to increase. The local spatial autocorrelation of resource adaptation verifies that the middle and lower reaches of the Yangtze River as the core form a hot spot, and during the observation period, the spatial agglomeration effect of the core is strengthened. The Theil index decomposition of resource adaptation indicates that the within-group differences between the eastern and western regions is significantly higher than that between the northeastern and central regions.

CONCLUSIONS

First, special attention should be paid to preventing the resource allocation of rural institutional elderly care in the eastern and western regions from falling again. Second, to avoid more and more low-adapted provinces falling into the 'mismatch dilemma' with the deepening of the aging degree. Third, strengthen cooperation among regions and promote the coordinated development of resource allocation of institutional elderly care in various regions. Fourth, the priority of institutional elderly care balanced development should be given to the eastern region and western region, thus weakening the overall difference.

Lesion environments direct transplanted neural progenitors towards a wound repair astroglial phenotype in mice

Neural progenitor cells (NPC) represent potential cell transplantation therapies for CNS injuries. To understand how lesion environments influence transplanted NPC fate in vivo, we derived NPC expressing a ribosomal protein-hemagglutinin tag (RiboTag) for transcriptional profiling of transplanted NPC. Here, we show that NPC grafted into uninjured mouse CNS generate cells that are transcriptionally similar to healthy astrocytes and oligodendrocyte lineages. In striking contrast, NPC transplanted into subacute CNS lesions after stroke or spinal cord injury in mice generate cells that share transcriptional, morphological and functional features with newly proliferated host astroglia that restrict inflammation and fibrosis and isolate lesions from adjacent viable neural tissue. Our findings reveal overlapping differentiation potentials of grafted NPC and proliferating host astrocytes; and show that in the absence of other interventions, non-cell autonomous cues in subacute CNS lesions direct the differentiation of grafted NPC towards a naturally occurring wound repair astroglial phenotype.

Aminotriazole isomers modified cellulose microspheres for selective adsorption of U(VI): Performance and mechanism investigation

Aminotriazole isomers with high nitrogen content show potential affinity for U(VI). Combining the advantages of both aminotriazole and cellulose, two n-aminotriazole isomers modified cellulose microspheres (n-ATARs, n = 3, 4) were newly prepared as adsorbents via radiation technology. Batch adsorption experiments showed that n-ATARs possessed good adsorption capacity of U(VI) in the order of 3-ATAR > 4-ATAR, and the adsorption process followed the Langmuir-Freundlich isotherm model and the pseudo-second-order kinetic model. Both n-ATARs exhibited good selectivity and reusability. Besides, 3-ATAR and 4-ATAR were more suitable for the extraction of trace amount of U(VI) from the contaminated groundwater and the simulated seawater, respectively. The effect of amino position on triazole ring on adsorption behavior of n-ATAR was studied and explained by DFT calculation. Finally, the adsorption mechanism of U(VI) onto n-ATARs was revealed to be inner-sphere complexation via different 1:1 or 1:2 coordination models by FTIR, MS, XPS analysis and DFT calculation.

Facile preparation of L-cysteine-modified cellulose microspheres as a low-cost adsorbent for selective and efficient adsorption of Au(III) from the aqueous solution

A facile method to synthesize adsorbent based on cellulose modified by amino acid was developed. The novel L-cysteine-functionalized adsorbent for Au(III) recovery was synthesized via radiation grafting technique. Glycidyl methacrylate (GMA) was grafted on the surface of microcrystalline cellulose microsphere (MCC); next, ring-opening reaction was performed to immobilize L-cysteine. The adsorption abilities of the adsorbent (CysR) were tested. Batch experiments suggested that the maximum adsorption capacity of Au(III) is 714.28 mg/g calculated by Langmuir model. The adsorption kinetic data was followed by pseudo-second-order model. CysR showed excellent selectivity for Au(III) even the concentration of competing ions was all ten times than that of Au(III). The column experiments revealed that Au(III) could be efficiently adsorbed by CysR competition with equal amounts of Ni(II) and Zn(II). Moreover, XPS analysis demonstrated that the adsorbed Au(III) was reduced to Au(I) and Au(0). The adsorption performance certified that CysR was a promising adsorbent for Au(III) recovery.

The functional difference of eight chitinase genes between male and female of the cotton mealybug, Phenacoccus solenopsis

The cotton mealybug Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) is a polyphagous insect that attacks tens of plant and causes substantial economic loss. Insect chitinases are required to remove the old cuticle to allow for continued growth and development. Though insect chitinases have been well studied in tens of insects, their functions in mealybug are still not addressed. Here, we sequenced the transcriptomes of adult males and females, from which eight chitinase genes were identified. We then used the method of rapid amplification of cDNA ends to amplify their full length. Phylogenetic analysis indicated that these genes clustered into five subgroups. Among which, group II PsCht2 had the longest transcript and was highly expressed at second instar nymph. PsCht10, PsCht3-3 and PsIDGF were highly expressed in the adult females, whereas PsCht4 and PsCht4-1 were significantly expressed at the male pupa and adult male. Next, we knocked down all eight chitinase genes by feeding the double-stranded RNA. Knockdown of PsCht4 or PsCht4-1 led to the failure of moult and, silencing PsCht5 resulted in pupation defect, while silencing PsCht10 led to small body size, suggesting these genes have essential roles in development and can be used as a potential target for pest control.

Radiolysis of alkyl substituted tridentate 2,6-bis(1,2,4-triazine-3-yl)pyridines: an experimental study with DFT validation

The radiolysis products of alkyl substituted tridentate 2,6-bis(1,2,4-triazine-3-yl)pyridines (BTPs) were studied by an experimental study with DFT validation.

Extraction performance of Eu3+ by using heterocyclic N-donor ligands with different structures in ionic liquids: an experimental and theoretical study

Extraction performance of Eu³⁺ has been studied for heterocyclic N-donor ligands with different structures in [C₂mim][NTf₂] as a diluent.

Fast selective homogeneous extraction of UO22+ with carboxyl-functionalised task-specific ionic liquids

The carboxyl-functionalised task-specific ionic liquid of 1-carboxymethyl-3-methylimidazolium bis(trifluoromethyl-sulfonyl)imide ([HOOCmim][NTf₂]) was used as solvent and extractant for UO₂²⁺ extraction from aqueous solution. A homogeneous phase of [HOOCmim][NTf₂]-H₂O system could be achieved at 75 °C, and 86.8 ± 4.8% of UO₂²⁺ was separated from the aqueous solution after vibrating for only 1 min. Furthermore, nearly 97.3 ± 2.9% of UO₂²⁺ was stripped from [HOOCmim][NTf₂] phase by 1 M HNO₃ solution. K⁺, Na⁺, Mg²⁺, Dy³⁺, La³⁺, and Eu³⁺ have little influence on the homogeneous extraction of UO₂²⁺, and the extraction efficiency of UO₂²⁺ still remained at ca. 80%. Experimental and theoretical study on the selectivity of [HOOCmim][NTf₂]-H₂O system were performed for the first time. Density functional theory calculation indicates that the solvent effect plays a significant role on the selectivity of [HOOCmim][NTf₂]-H₂O.

Radiation Effect of Carboxyl-Functionalized Task-Specific Ionic Liquids on UO22+ Removal: Experimental Study with DFT Validation

Experimental study with DFT validation on the effect of radiation on 1-carboxymethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([HOOCCH₂MIM][NTf₂]) as a solvent and extractant in rapid homogeneous extraction of UO₂²⁺ was performed for the first time. The radiolytic products of the anions and cations of [HOOCCH₂MIM][NTf₂] were identified by ¹⁹F NMR and high-resolution ESI-MS, respectively, and they were attributed to a decrease in UO₂²⁺ partitioning. Experimental study with DFT validation for complexing reactions between [HOOCCH₂MIM][NTf₂] and radiolytic products proved that F^- competition was one of the main reasons for the decrease in UO₂²⁺ partitioning. However, UO₂²⁺ partitioning in irradiated [HOOCCH₂MIM][NTf₂] can largely be recovered after thorough water washing because of the removal of radiolytic products of [NTf₂]^-.

Characterization and comparison of flower bud microRNAs from yellow-horn species

An increasing number of microRNAs (miRNAs) are known to play crucial regulatory roles in floral organ differentiation and development. Yellow-horn (Xanthoceras sorbifolia Bunge) is an oil-rich seed shrub that has great potential for biodiesel production. To evaluate the roles of miRNAs in the regulation of flower development, we used high-throughput sequencing to characterize them from flower buds of double-flower yellow-horn mutant and wild-type plants. Approximately 33 million raw reads were obtained through Solexa sequencing of two small RNA libraries, and the conserved and novel miRNA locations were annotated. Nineteen conserved miRNAs (belonging to nine families) and eight novel miRNAs were identified from the two libraries. Twelve conserved and eight novel miRNA-star sequences were also discovered, providing additional evidence for the existence of miRNAs in this species. Thirteen miRNAs were differentially expressed between wild-type and mutant plants. Real-time reverse transcription-polymerase chain reaction analysis revealed the expression patterns of eight microRNAs, which were confirmed by sequencing. The assessed targets of these miRNAs are involved in transcriptional regulation, disease resistance, antioxidative metabolism, nucleobase regulation, and nucleic acid metabolism. This study opens up new avenues for understanding the roles of miRNAs in X. sorbifolia.

γ-Radiation effect on Th4+ extraction behaviour of TODGA/[C2mim][NTf2]: identification and extractability study of radiolytic products

TODGA would react with [C₂mim]⁺ radical under γ-radiation, this radiolytic product kept integral functional group and possessed extractability for Th⁴⁺.

Intra-articular delivery of anti-Hif-2α siRNA by chondrocyte-homing nanoparticles to prevent cartilage degeneration in arthritic mice

Hypoxia-inducible factor-2α (Hif-2α) is a potential therapeutic target for osteoarthritis (OA), but the application of this target in the delivery of therapeutic agents to chondrocytes remains a challenge. A chondrocyte-targeting vector was constructed in a previous study to enhance transfection efficiency and specificity of chondrocytes in vivo. This study used vectors to deliver small-interfering RNA (siRNA) and silenced Hif-2α expression to prevent cartilage degeneration in OA-affected mice. After siRNA transfection was conducted by cartilage-targeting nanoparticles, the protein levels of Hif-2α, matrix metalloproteinases (MMP-13, -9), a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS-4, -5), vascular endothelial growth factor (VEGF), type X collagen and nuclear factor (NF)-κB in interleukin-1-beta (IL-1β)-stimulated chondrocytes were determined. Chondrocyte-targeting ability was also determined by fluorescein isothiocyanate (FITC)-labeled siRNA tracking under a confocal microscope. OA model was established by surgically destabilizing the knee joints of a mouse. Hif-2α siRNA was then delivered intra-articularly with nanoparticles in vivo. Cartilage degeneration and synovium inflammation in the knee joints were analyzed by histomorphometry. IL-1β levels in the synovial fluid were also measured by enzyme-linked immunosorbent assay. In vitro assay results showed that catabolic factors, including Hif-2α, MMP-13 and -9, ADAMTS-4, VEGF, collagen type X and NF-κB, were downregulated after Hif-2α-siRNA transfection by chondrocyte-targeting nanoparticles. In vivo assay results with FITC-labeled siRNA tracking also confirmed that nanoparticles promoted the local concentration and prolonged the retention time of siRNA in the cartilage. Histological analysis results confirmed that nanoparticle-mediated siRNA maintained cartilage integrity and alleviated synovium inflammation. IL-1β levels decreased after siRNA was silenced by nanoparticles. Thus, chondrocyte-targeting nanoparticles could deliver Hif-2α siRNA to cartilage and specifically inhibit the expression of catabolic proteins.

Radiolysis of crown ether–ionic liquid systems: identification of radiolytic products and their effect on the removal of Sr2+ from nitric acid

The quantitative analysis and identification of the radiolytic products of dicyclohexano-18-crown-6 (DCH18C6), 4′,4′′(5′′)-di-tert-butyldicyclohexano-18-crown-6 (DtBuCH18C6) and benzo-18-crown-6 (B18C6) in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([C₄mim][NTf₂]) ionic liquid after irradiation were performed for the first time.

α-Radiolysis of ionic liquid irradiated with helium ion beam and the influence of radiolytic products on Dy3+extraction

Helium ion beam produced by a heavy ion linear accelerator was used to simulate α-rays for studying the radiation effect on 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid.

Extraction mechanism and γ-radiation effect on the removal of Eu3+ by a novel BTPhen/[Cnmim][NTf2] system in the presence of nitric acid

The extraction mechanism of Eu³⁺ by using BTPhen/[C_nmim][NTf₂] (n = 2, 4, 8) was investigated in the presence of nitric acid, and the new extraction system shows high radiation stability.

Influence of radiation effect on extractability of an isobutyl-BTP/ionic liquid system: quantitative analysis and identification of radiolytic products

Approaches were established for assessing the influence of radiation effect on the extractability of the 2,6-di(5,6-diisobutyl-1,2,4-triazin-3-yl)pyridine (isobutyl-BTP)/1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([C₂mim][NTf₂]) extraction system.

Food-intake dysregulation in type 2 diabetic Goto-Kakizaki rats: hypothesized role of dysfunctional brainstem thyrotropin-releasing hormone and impaired vagal output

Thyrotropin-releasing hormone (TRH), a neuropeptide contained in neural terminals innervating brainstem vagal motor neurons, enhances vagal outflow to modify multisystemic visceral functions and food intake. Type 2 diabetes (T2D) and obesity are accompanied by impaired vagal functioning. We examined the possibility that impaired brainstem TRH action may contribute to the vagal dysregulation of food intake in Goto-Kakizaki (GK) rats, a T2D model with hyperglycemia and impaired central vagal activation by TRH. Food intake induced by intracisternal injection of TRH analog was reduced significantly by 50% in GK rats, compared to Wistar rats. Similarly, natural food intake in the dark phase or food intake after an overnight fast was reduced by 56-81% in GK rats. Fasting (48h) and refeeding (2h)-associated changes in serum ghrelin, insulin, peptide YY, pancreatic polypeptide and leptin, and the concomitant changes in orexigenic or anorexigenic peptide expression in the brainstem and hypothalamus, all apparent in Wistar rats, were absent or markedly reduced in GK rats, with hormone release stimulated by vagal activation, such as ghrelin and pancreatic polypeptide, decreased substantially. Fasting-induced Fos expression accompanying endogenous brainstem TRH action decreased by 66% and 91%, respectively, in the nucleus tractus solitarius (NTS) and the dorsal motor nucleus of the vagus (DMV) in GK rats, compared to Wistar rats. Refeeding abolished fasting-induced Fos-expression in the NTS, while that in the DMV remained in Wistar but not GK rats. These findings indicate that dysfunctional brainstem TRH-elicited vagal impairment contributes to the disturbed food intake in T2D GK rats, and may provide a pathophysiological mechanism which prevents further weight gain in T2D and obesity.

Two novel mutations and evidence for haploinsufficiency of the ADAR gene in dyschromatosis symmetrica hereditaria

BACKGROUND

Dyschromatosis symmetrica hereditaria (DSH, MIM 127400) is a dominantly inherited skin disease associated with mutations in ADAR, the gene that encodes a double-stranded RNA-specific adenosine deaminase. We previously reported two novel ADAR mutations (p.Q513X and p.R916W) and confirmed the role of ADAR in Chinese patients with DSH. Both haploinsufficiency and a dominant-negative effect have been suggested as the potential mechanism by which ADAR mutations cause DSH.

OBJECTIVES

To identify ADAR mutations in two additional Chinese DSH families and to obtain insight into the pathogenic mechanism of heterozygous ADAR mutations.

METHODS

For mutation detection, all ADAR exons and their flanking intronic sequences were amplified and sequenced. Mutations were further confirmed by restriction analysis. Direct sequencing of cDNA fragments produced by reverse transcription-polymerase chain reaction (RT-PCR) and real-time quantitative RT-PCR were used to examine the expression of ADAR in peripheral lymphocytes isolated from affected individuals.

RESULTS

A small deletion, c.1555delT (p.C519fs), and a missense mutation, c.3116A>G (p.K1039R), were found in families A and B, respectively. In individuals carrying p.Q513X or p.C519fs, sequencing of cDNA fragments indicated almost total loss of mRNA expression from the mutant alleles, and real-time quantitative RT-PCR showed an approximately 50% reduction of ADAR expression. However, equal abundance of the wild-type and mutant cDNA sequences without reduction of ADAR expression was found in a patient with the missense p.R916W mutation. These results suggest that both the nonsense p.Q513X and frameshift p.C519fs mutations have generated null alleles probably by nonsense-mediated mRNA decay.

CONCLUSIONS

Two novel ADAR mutations were found in Chinese patients with DSH. Evidence for ADAR haploinsufficiency as a mechanism underlying the molecular pathogenesis of DSH was obtained.

Peripheral secretin-induced Fos expression in the rat brain is largely vagal dependent

I.v. injection of secretin activates neurons in brain areas controlling autonomic function and emotion. Peripheral administration of secretin inhibits gastric functions through a central mechanism that is mediated by vagal dependent pathways. We investigated whether the vagus nerve is involved in i.p. injection of secretin-induced brain neuronal activation in conscious rats as monitored by Fos immunohistochemistry. Secretin (40 or 100 microg/kg, i.p., 90 min) induced a dose-related increase in the number of Fos positive neurons in the central nucleus of the amygdala (CeA), and a plateau Fos response in the area postrema (AP), nucleus tractus solitarii (NTS), locus coeruleus (LC), Barrington's nucleus (Bar), external lateral subnucleus of parabrachial nucleus (PBel) and arcuate nucleus, and at 100 microg/kg, in the dorsal motor nucleus of the vagus (DMV) compared with i.p. injection of vehicle. Double immunohistochemistry showed that secretin (40 microg/kg, i.p.) activates tyrosine hydroxylase neurons in the NTS. Subdiaphragmatic vagotomy (7 days) abolished Fos expression-induced by i.p. secretin (40 microg/kg) in the NTS, DMV, LC, Bar, PBel and CeA, while a significant rise in the AP was maintained. In contrast, s.c. capsaicin (10 days) did not influence the Fos induction in the above nuclei. Reverse transcription polymerase chain reaction (RT-PCR) and quantitative real-time PCR showed that secretin receptor mRNA is expressed in the nodose ganglia and levels were higher in the right compared with the left ganglion. These results indicate that peripheral secretin activates catecholaminergic NTS neurons as well as neurons in medullary, pontine and limbic nuclei regulating autonomic functions and emotion through vagal-dependent capsaicin-resistant pathways. Secretin injected i.p. may signal to the brain by interacting with secretin receptors on vagal afferent as well as on AP neurons outside the blood-brain barrier.

p53-interacting protein 53BP2 inhibits clonogenic survival and sensitizes cells to doxorubicin but not paclitaxel-induced apoptosis

53BP2 was initially identified as a protein interacting with p53 in a yeast two-hybrid screen and subsequently shown to enhance p53 transcriptional transactivation and induce apoptosis when transiently overexpressed in cell lines. In order to further study the biologically relevant effects of 53BP2, we have constructed HEK293 stable cell lines where 53BP2 expression can be regulated using an ecdysone inducible expression system. Our results indicate that the response of cells is dependent on the amount of 53BP2 that is expressed. High levels of 53BP2 expression (>or=140-fold above endogenous) impede cell cycle progression and induce apoptosis. Lower levels of 53BP2 expression (6-11-fold above endogenous) suppress colony formation but do not lead to detectable perturbations in the cell cycle or apoptosis. Lower levels of 53BP2 expression sensitized cells to apoptosis induced by DNA damaging chemotherapy agents doxorubicin, ara-C and VP16, but not microtubule active agents paclitaxel and vinblastine. Our results demonstrate that high levels of 53BP2 expression have profound biological effects ultimately leading to apoptosis, whereas lower levels of 53BP2 expression have more subtle effects on growth and sensitize cells to some chemotherapy agents.

[Quantitative analysis for inheritance of quality characters in indica hybrid rice]

Nine quality characters of 3 sterile lines, 10 restorers and their 30 indica hybrid rice by NC II genetic design were studied. The results showed as follows: (1) No genetic segregation occurred in F2 grains in grain length, grain width, grain weight, brown rice% and head rice%, which indicated these traits are completely controlled by maternal plant genotypes. (2) Significant genetic segregation occurred in F2 grains in chalkiness score, amylose content, gelatinization temperature and gel consistency, which indicated the genetic expression of these traits is mainly controlled by endosperm genotypes. (3) The quality characters have relatively high heritabilities except brown rice % and chalkiness score. The genetic variation of quality characters was mainly caused by additive effect except grain weight.

Proapoptotic p53-interacting protein 53BP2 is induced by UV irradiation but suppressed by p53

p53 is an important mediator of the cellular stress response with roles in cell cycle control, DNA repair, and apoptosis. 53BP2, a p53-interacting protein, enhances p53 transactivation, impedes cell cycle progression, and promotes apoptosis through unknown mechanisms. We now demonstrate that endogenous 53BP2 levels increase following UV irradiation induced DNA damage in a p53-independent manner. In contrast, we found that the presence of a wild-type (but not mutant) p53 gene suppressed 53BP2 steady-state levels in cell lines with defined p53 genotypes. Likewise, expression of a tetracycline-regulated wild-type p53 cDNA in p53-null fibroblasts caused a reduction in 53BP2 protein levels. However, 53BP2 levels were not reduced if the tetracycline-regulated p53 cDNA was expressed after UV damage in these cells. This suggests that UV damage activates cellular factors that can relieve the p53-mediated suppression of 53BP2 protein. To address the physiologic significance of 53BP2 induction, we utilized stable cell lines with a ponasterone A-regulated 53BP2 cDNA. Conditional expression of 53BP2 cDNA lowered the apoptotic threshold and decreased clonogenic survival following UV irradiation. Conversely, attenuation of endogenous 53BP2 induction with an antisense oligonucleotide resulted in enhanced clonogenic survival following UV irradiation. These results demonstrate that 53BP2 is a DNA damage-inducible protein that promotes DNA damage-induced apoptosis. Furthermore, 53BP2 expression is highly regulated and involves both p53-dependent and p53-independent mechanisms. Our data provide new insight into 53BP2 function and open new avenues for investigation into the cellular response to genotoxic stress.

[Early arthroscopic reconstruction in treatment of acute complete rupture of anterior cruciate ligament]

OBJECTIVE

To early reconstruct acute and complete rupture of anterior cruciate ligament (ACL) and treat combined injuries for the recovery of knee joint stability.

METHODS

Ten cases of acute complete rupture of anterior cruciate ligament and medial collateral ligament were treated arthroscopically by anterior cruciate ligament reconstruction using patellar tendon autograft fixed with interference screw from February 1998 to March 1999.

RESULTS

Follow-up ranged from 5 months to 1 year and 3 months (average 10 months). Clinical results showed that the stability of knee joint was satisfactory in the early stage.

CONCLUSIONS

Acute the ACL rupture can be reconstructed arthroscopically in the early stage and the injuries were moderate, combined injuries could be treated at the same time, and the stability of knee joint could recover in the early stage after operation.

[Arthroscopically assisted anterior cruciate ligament reconstruction using patellar tendon autograft fixed with interference screw]

OBJECTIVES

To evaluate the optimal position of bony tunnel, the firmness of tendon graft fixation and the effectiveness of postoperative function recovery in an arthroscopic approach for the minimally invasive reconstruction of anterior cruciate ligament (ACL).

METHODS

In a single arthroscopic approach, the ACL was reconstructed by the bone-tendon-bone compound patellar tendon autograft with the fixation of an interference screw.

RESULTS

ACL reconstruction was performed in 49 patients, of whom 20 were followed up for over one year (average 1 year and 5 months). Among the 20 patients, 13 were rated as excellent, 5 good, and 2 fair. The excellent and good rate went up to 90%. Reconstructed ACLs were reevaluated arthroscopically in 9 patients, in whom, 6 had good remodeling of ACLs.

CONCLUSIONS

Our results indicated that this method has the advantages of less injury, optimal positioning of bone tunnel, firm graft fixation, and early rehabilitation. Compound bone-tendon-bone autograft allows firm fixation and biologic healing with good shape and tension remodeling.

[Acute rupture of anterior cruciate ligament: diagnosis and treatment by early arthroscopy]

OBJECTIVE

To early diagnose and treat acute rupture of anterior cruciate ligament (ACL).

METHODS

23 patients with acute rupture of ACL were examined and treated by early arthroscopy.

RESULTS

The preoperative diagnosis of ACL rupture was similar to that of in 18 patients. Three patients were confirmed by early arthroscopy and 2 patients were found to have ACL rupture, 16 patients were combined with meniscus injuries and 6 patients with cartilaginous injuries. Patholanatomical type of ACL were rupture of parenchymal part (21 patients) and avulsion rupture of attachment point (2 patients). In 6 patients ACL was reconstructed under arthroscope.

CONCLUSIONS

Early arthroscopy in the treatment of acute ACL rupture has advantages of minor injury, correct diagnosis, visible location of injury or combined injury and timely treatment. Early arthroscopy for acute ACL rupture is an important measure for diagnosis, treatment, and stabilization of the knee joint.

Activation of cAMP-dependent protein kinase is required for optimal alpha-melanocyte-stimulating hormone-induced pigmentation

The cAMP-dependent pathway has been long presumed to play a critical role in mediating alpha-melanocyte-stimulating hormone (alpha-MSH)-induced pigmentation, but it has never been demonstrated that this pathway is obligatory. In order to determine whether the cAMP-dependent pathway is required for a alpha-MSH-induced pigmentation, we inhibited the activity of cAMP-dependent protein kinase (PKA), the main kinase mediating in this pathway, by introducing a physiologic cAMP-dependent protein kinase inhibitor (PKI) into S91 murine melanoma cells and then measuring pigment response after alpha-MSH stimulation. Cells were stably transfected either with the pMXX-PKI expression vector that encodes the active part of PKI (the amino terminal 1-31 amino acids) under a metallothionein-inducible promoter and the pSV2-Neo expression vector alone. As expected, treatment of transfected cells with 1 microM CdCl2 for 24 h induced the expression of PKI mRNA in cells transfected with both vectors, but not in cells transfected with the pSV2-Neo expression vector alone. Subsequent treatment of these transfected cells with alpha-MSH for 5-6 days in the continual presence of 1 microM CdCl2 resulted in inhibition of PKA activity by 30-40% in cells expressing PKI. Parallel measurements revealed that alpha-MSH-increased melanin content five- to six-fold in control cells transfected with pSV2-Neo alone, while there was only a two-fold increase in PKI-expressing cells, a 40-50% inhibition in alpha-MSH-induced total melanin content. alpha-MSH-induced tyrosinase activity and tyrosinase mRNA and protein levels measured in parallel were also inhibited by 40-50% in PKI-expressing cells compared to control cells transfected with pSV2-Neo alone. Together, these results demonstrate for the first time that activation of PKA through the cAMP-dependent pathway is required for optimal alpha-MSH-induced pigmentation.

[Reconstruction of anterior cruciate ligament using bone-patellar tendon-prepatellar periosteum free graft with impacting bone technique]

In order to make full and effective use of patellar tendon (middle one-third) during reconstruction of anterior cruciate ligament, we designed bone-patellar tendon-tendon of quadriceps femoris free graft with impacting bone technique and 38 cases were treated by this method. Follow-up for 2 years and 7 months showed that the clinical results were good. The exellent and good rate was 89.7%. Clinical results indicated that the fixation of this reconstructive method was firm and grafts in the joint cavity were patellar tendon tissue. The anterior medial rotatory instability of the knee joint could be corrected with the same graft that have enough length. The experience of acute rupture of anterior cruciate ligament and the rupture of anterior cruciate ligament combined with injury of meniscus were reported.

Lysophosphatidic acid sensitises Ca2+ influx through mechanosensitive ion channels in cultured lens epithelial cells

We investigated the effect of lysophosphatidic acid (LPA), a bioactive phospholipid, on the response in cytosolic free Ca2+ concentration ([Ca2+]i) to mechanical stress in cultured bovine lens epithelial cells. Spritzing of bath solution onto cells as mechanical stress caused marked increase in [Ca2+]i in the presence of LPA and this increase was concentration-dependent (1-10 microM), whereas neither addition of LPA alone nor the mechanical stress in the absence of LPA affected [Ca2+]i. The mechanical stress-induced increase in [Ca2+]i in the presence of LPA was inhibited by removing extracellular Ca2+ or by addition of Gd3+, a blocker of mechanosensitive cation channels, but not by nicardipine, thapsigargin, an inhibitor of endoplasmic reticulum-ATPase pump, or U73122, a phospholipase C inhibitor. These results show that LPA sensitises Ca2+ influx through cation-selective mechanosensitive channels, but does not sensitise Ca2+ release from intracellular stores, triggered by changes in mechanical stress. On the other hand, phosphatidic acid had less of a sensitising effect than LPA, and neither lysophosphatidylcholine nor chlorpromazine had any effect. Also Ca2+ mobilising agonists, ATP, histamine and carbachol, did not sensitise Ca2+ response to the mechanical stress. These results show that LPA sensitises mechanoreceptor-linked response in lens epithelial cells, suggesting that it plays a role in the development of cataracts due to increases in [Ca2+]i induced by mechanical stress.

Rapid determination of ascorbate by ESR spectroscopy

Optimal conditions for the determination of ascorbate, based on the detection of its radical by ESR spectroscopy, were established. The optimal pH for the measurement of the ascorbate radical was 10, whereas that for the gallate and caffeate radical was much higher. This was due to the liability of the ascorbate radical at higher pH. When the radical intensity of ascorbate vs. concentration was plotted double logarithmically, a linear correlation was established between these two parameters within the ascorbate concentration of 0.03-10 mM. ESR analysis of the homogenates under alkaline condition demonstrated that ascorbate is distributed in various mouse organs and that the ascorbate radical is unstable at neutral pH in the brain and liver, suggesting the presence of metabolizing substances. The present study suggests the applicability of the present technique for the study of ascorbate metabolism and identification of physiological factors which regulate the radical intensity of ascorbate.

Alpha-melanocyte stimulating hormone-induced pigmentation is blocked by depletion of protein kinase C

We have explored the role of protein kinase C (PKC) in pigmentation induced by alpha-melanocyte stimulating hormone (alpha-MSH). Using the well-studied S91 Cloudman mouse melanoma model system in which 10(-7) M alpha-MSH is known to produce a time-dependent increase in pigmentation, we found an increase in the activity of tyrosinase, the key enzyme in pigmentation, between Days 2 and 6 accompanied by an increase in mRNA and protein levels of tyrosinase, as well as an increase in the level of specifically the beta isoform of PKC. When S91 cells were treated with phorbol dibutyrate, 95% of PKC activity was lost within 48 h and the alpha-MSH-induced melanogenesis was completely blocked, as was the induction of tyrosinase mRNA and protein. Serially passaged S91 cells no longer capable of responding to alpha-MSH had an undetectable level of PKC-beta, although the tyrosinase protein level was identical to that of alpha-MSH-responsive cells. Furthermore, in these S91 cells alpha-MSH also did not increase the level of tyrosinase mRNA. Thus, induction of murine melanogenesis by alpha-MSH involves up-regulation of tyrosinase mRNA and protein mediated in part by the PKC-dependent pathway, associated with an up-regulation of the beta isoform previously demonstrated to specifically activate tyrosinase in human melanocytes.