The association between glucose fluctuation with sarcopenia in elderly patients with type 2 diabetes mellitus.

OBJECTIVE: Growing evidence shows that sarcopenia is more prevalent in patients with type 2 diabetes mellitus (T2DM) than in the normal population. However, currently, data on the relationship between blood glucose fluctuation and sarcopenia in elderly patients with T2DM are still limited. PATIENTS AND METHODS: In this study, 280 patients ≥ 60 years with T2DM were divided into sarcopenic group and non-sarcopenic group, according to the diagnostic criteria of the 2019 Asian Working Group for Sarcopenia. They wore MeiQi to acquire the indexes including time in range (TIR), time above range (TAR), time below range (TBR), mean amplitude of glycemic excursion (MAGE), coefficient of Variation (CV), blood glucose standard deviation (SD), largest amplitude of glycemic excursions (LAGE) and mean glucose (MG). The prevalence rate of sarcopenia was statistically analyzed and the different indicators of glucose fluctuation between the two groups were compared. We analyzed the indexes of glucose fluctuation and appendicular skeletal muscle mass index (ASMI), handgrip strength, the time of five times sit to stand test (FTSST) with Spearman's correlation analysis. Logistic regression was used to analyze the influence factors for sarcopenia. RESULTS: The prevalence of sarcopenia was 15.36%. TIR, MG and TAR were correlated with ASMI, handgrip strength, the time of FTSST. MG and TAR were risk factors for sarcopenia, while TIR was the protective factor of sarcopenia. After adjusting mixing factors, logistic regression analysis showed that TIR was an independent protective factor. The result of the Chi-square test showed that the incidence of sarcopenia in different TIR ranges was different: the proportion of patients with sarcopenia was 40.48% (TIR ≤50%), 20.41% (50%70%). CONCLUSIONS: TIR is associated with sarcopenia in elderly T2DM patients. Furtherly, the incidence rate of sarcopenia decreases with the increase of TIR.

Construction of a Streptococcus iniae sortase A mutant and evaluation of its potential as an attenuated modified live vaccine in Nile tilapia (Oreochromis niloticus).

Streptococcus iniae is a major Gram-positive aquatic pathogen, which causes invasive diseases in cultured fish worldwide. The identification of potential virulence determinants of streptococcal infections will help to understand and control this disease, but only a few have been confirmed in S. iniae. Sortase A (srtA) is the key enzyme that anchors pre-mature cell wall-attached proteins to peptidoglycan and it can affect the correct positioning of surface proteins, as well as the course of Gram-positive bacterial infection, thereby making it a potential target in the study of virulence factors and disease control. In this study, the 759 bp srtA gene was cloned from pathogenic S. iniae TBY-1 strain and the mutant strain TBY-1ΔsrtA was constructed via allelic exchange mutagenesis. We found that srtA shares high similarities with sortase A from other Streptococcus spp. Direct survival rate assay and challenge experiments were performed, which showed that the mutant strain TBY-1ΔsrtA had a lower survival capacity in healthy tilapia blood and it was less virulent than the wild type strain in tilapia, thereby indicating that the deletion of sortase A affects the virulence and infectious capacity of S. iniae. The mutant strain TBY-1ΔsrtA was used as a live vaccine, which was administered via intraperitoneal injection, and it provided the relative percent survival value of 95.5% in Nile tilapia, thereby demonstrating its high potential as an effective attenuated live vaccine candidate.

Impedance analysis of secondary phases in a Co-implanted ZnO single crystal.

Co ions with 100 keV energy with a fluence of 1 × 10(15) cm(-2) are implanted into ZnO(0001) single crystals at 300 °C under vacuum. The resulting Co-implanted ZnO single crystals and the subsequent 750 °C and 900 °C annealed samples are analysed with respect to their structural, optical, electronic, magnetic and ac electrical properties. Photoluminescence and X-ray photoelectron spectroscopy results indicate the signatures of the Co(2+) state and its substitution at the tetrahedrally coordinated Zn-sites. X-ray diffraction and X-ray photoelectron spectroscopy identify the presence of the ZnCo2O4 and Co3O4 phases in the 900 °C annealed sample. By comparing the resistance response of the identified phases towards different magnetic environments, the impedance spectroscopy results successfully identify two magnetic phases (ZnCo2O4 and Co3O4) and a paramagnetic (CoZn) phase for the 750 °C and 900 °C annealed samples, implying the extrinsic nature of room temperature ferromagnetism. The observed ferromagnetism in each sample is not of single origin, instead the mutual effects of the secondary phases embedded in the paramagnetic host matrix are in competition with each other.

A novel iron transporter in Streptococcus iniae.

Streptococcus iniae is a major pathogen that results in considerable economic loss to fish farms. Restricted availability of iron is a huge obstacle to survival for pathogenic bacteria during infection, and iron acquisition is important in bacterial virulence. In this study, S. iniae HD-1 was shown not to produce siderophores (low-molecular-weight compounds) but rather to require iron-containing proteins for growth under iron-restricted conditions. The adenosine triphosphate (ATP)-binding-cassette (ABC) transporter system (ftsABCD), which is cotranscribed by four downstream genes, namely, ftsA, ftsB, ftsC and ftsD, was identified as responsible for haem utilization of S. iniae. Analysis of the corresponding recombinant protein, FtsB, indicated that it is a putative lipoprotein which plays a role in haem utilization and is produced in vivo during infection with S. iniae HD-1, and therefore may be a potential candidate antigen for a streptococcal vaccine.

Pyrosequencing for the rapid detection of rifampicin resistance in Mycobacterium tuberculosis: a meta-analysis.

BACKGROUND: Multidrug-resistant tuberculosis is a major threat to the control of tuberculosis and to public health. Whereas most conventional methods of drug susceptibility testing (DST) are precise but time consuming, pyrosequencing is a rapid, high-throughput technique. OBJECTIVE: To conduct a meta-analysis to evaluate the overall accuracy of pyrosequencing for the detection of rifampicin (RMP) resistance. METHODS: We searched PubMed, Web of Science, Elsevier and BIOSIS databases according to a written protocol and explicit study selection criteria. A summary receiver operating characteristic curve (SROC) and Cochrane (Q*) index were calculated to perform this meta-analysis using Meta-Disc software. RESULTS: Twelve studies involving 594 specimens with RMP resistance and 793 RMP-susceptible specimens met the inclusion criteria. Of these, 11 were based on Mycobacterium tuberculosis clinical isolates. The overall sensitivity and specificity were estimated at respectively 0.94 (95%CI 0.92-0.96) and 0.98 (95%CI 0.97-0.99). The area under the SROC curve was 0.99 and the Cochrane (Q*) index was 0.96. For clinical specimens, the overall sensitivity and specificity estimates were respectively 0.89 (range 0.52-1.00) and 0.99 (range 0.95-1.00). CONCLUSIONS: This meta-analysis shows that pyrosequencing is a highly sensitive and specific tool for the detection of RMP resistance in M. tuberculosis. The pyrosequencing assay is conducted in a high-throughput format, with a turnaround time of <2 h, making it substantially faster than conventional DST methods. We propose that pyrosequencing applied directly to clinical specimens instead of M. tuberculosis isolates could be of greater clinical value.

Liposome-mediated NGF gene transfection following neuronal injury: potential therapeutic applications.

We have systematically investigated the therapeutic potential of cationic liposome-mediated neurotrophic gene transfer for treatment of CNS injury. Following determination of optimal transfection conditions, we examined the effects of dimethylaminoethane-carbamoyl-cholesterol (DC-Chol) liposome-mediated NGF cDNA transfection in injured and uninjured primary septo-hippocampal cell cultures and rat brains. In in vitro studies, we detected an increase of NGF mRNA in cultures 1 day after transfection. Subsequent ELISA and PC12 cell biological assays confirmed that cultured cells secreted soluble active NGF into the media from day 2 after gene transfection. Further experiments showed that such NGF gene transfection reduced the loss of chol- ine acetyltransferase (ChAT) activity in cultures following calcium-dependent depolarization injury. In in vivo studies, following intraventricular injections of NGF cDNA complexed with DC-Chol liposomes, ELISA detected nine- to 12-fold increases of NGF in rat CSF. Further studies showed that liposome/NGF cDNA complexes could attenuate the loss of cholinergic neuronal immunostaining in the rat septum after traumatic brain injury (TBI). Since deficits in cholinergic neurotransmission are a major consequence of TBI, our studies demonstrate for the first time that DC-Chol liposome-mediated NGF gene transfection may have therapeutic potential for treatment of brain injury.

D1/D2 dopamine receptor interaction in membrane abolished by 6-hydroxydopamine lesion.

D1/D2 interaction in rat striatum was investigated by examining the effect of the D2 antagonist spiperone on the binding of [3H]SCH23390 to D1 dopamine (DA) receptors. In the presence of endogenous DA, spiperone blocked D2 receptors, then caused the increase of the binding of [3H]SCH23390 in rat striatal homogenate. After the 6-hydroxydopamine (6-OHDA) lesion, the increase was not found even if in the addition of exogenous DA. The results suggest that the D2 antagonist can modify the interaction between endogenous DA and D1 receptors labeled with [3H]SCH23390, while 6-OHDA lesion may change the state of D1/D2 interaction operating at the receptor level.

Enhancement of (-)-stepholidine on protein phosphorylation of a dopamine- and cAMP-regulated phosphoprotein in denervated striatum of oxidopamine-lesioned rats.

AIM: To study effects of (-)-stepholidine (SPD) on the phosphorylation of a dopamine- and cAMP-regulated phosphoprotein (DARPP-32) in the striatum of oxidopamine-lesioned rats. METHODS: The amount of dephospho-DARPP-32 was measured by a back-phosphorylation assay. RESULTS: In the striatum of control rats, SPD per se had no effect on the phosphorylation of DARPP-32, but it antagonized the decrease by 28% of dephospho-DARPP-32 induced by the D1 agonist SK&F-38393. In the denervated striatum of oxidopamine-lesioned rats, SPD decreased the amount of dephospho-DARPP-32 by 44%. The effect of SPD was completely counteracted by the concomitant administration of the D1 antagonist Sch-23390. CONCLUSION: SPD exhibits D1 agonistic action on DARPP-32 phosphorylation in the denervated striatum of oxidopamine-lesioned rats, but it acts as a D1 antagonist in normal striatum.

Involvement of receptor reserve in D1 agonistic action of (-)-stepholidine in lesioned rats.

(-)-Stepholidine (SPD) is a natural product. Previous studies had demonstrated that SPD displayed D1 agonism in unilaterally 6-hydroxydopamine (6-OHDA)-lesioned rats and D1 antagonism in reserpinized rats and normal rats. The aim of the present study was to explain this peculiar pharmacological action based on behavioral and biochemical experiments. In the unilaterally 6-OHDA-lesioned rats, SPD (4 mg/kg, s.c.) induced contralateral rotation as did apomorphine (APO), but the rotation response to SPD was 60% lower than that to APO (0.5 mg/kg, i.p.). Coadministration with APO (0.5 mg/kg, i.p.) and SPD (0.5 to 10 mg/kg, s.c.) produced a biphasic action curve. At low doses (0.5 or 1 mg/kg), SPD potentiated APO action; at high doses (4 or 10 mg/kg), however, SPD suppressed APO. In striatal homogenate of the unilaterally lesioned rats, SPD stimulated cyclic AMP (cAMP) formation and produced a maximal response comparable to that of dopamine (DA) in the denervated striatum, but 70% lower than that of DA in the intact striatum. Coadministration of 10 microM DA with various concentrations of SPD yielded different results, with a biphasic response in the intact side and a synergistic effect in the denervated side. Furthermore, based on the determination of receptor-mediated cAMP formation, the D1 receptor reserve was analyzed in both denervated and intact striatum by using the DA receptor inactivator N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ). The results showed that following EEDQ administration, the receptor density [revealed by [3H]R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-be nzazepine ([3H]SCH-23390) binding] and the agonist-stimulated adenylate cyclase (AC) activity (revealed by cAMP formation) were reduced concurrently. In the intact striatum, the reduction in SPD-stimulated AC activity paralleled the receptor loss, indicating the absence of receptor reserve, while in the denervated striatum the reduction in AC activity was less than the receptor loss, indicating a significant level of receptor reserve (estimated 16.4%). By comparison, receptor reserve for DA was 45.7 and 25.3% in the denervated and intact striatum, respectively, representing an 80% increase of receptor reserve. In conclusion, SPD is a D1 partial agonist, and receptor reserve permits SPD to display its D1 agonistic action in the unilaterally 6-OHDA-lesioned rats.

Chronic treatment with (-)-stepholidine alters density and turnover of D1 and D2 receptors in striatum.

AIM: To study the effects of chronic administration of SPD on the density and turnover of striatal D1 and D2 dopamine (DA) receptors. METHODS: Receptor density was monitored by radio-receptor binding assay. The receptor recovery and turnover were studied after irreversible inactivation by N-ethoxycarbonyl-2-ethoxy-1, 2-dihydro-quinoline (EEDQ). RESULTS: Chronic SPD treatment (sc, 20 mg.kg-1.d-1 x 21 d) upregulated both striatal D1 and D2 receptor density. As compared to vehicle-treated rats, SPD increased D1 and D2 receptors by 41.5% and 43.7%, respectively SPD also altered the turnover of both D1 and D2 receptors. The degradation rate constant (k = 0.0082.h-1) and the synthesis rate (r = 2.65 pmol.h-1/g protein) of D2 receptors in SPD-treated rats were significantly increased vs vehicle-treated rats (k = 0.0049.h-1; r = 1.10 pmol.h-1/g protein). The degradation rate constant (k = 0.0059.h-1) and the synthesis rate (r = 3.1 pmol.h-1/g protein) of D1 receptors was also increased in SPD-treated rats vs vehicle-treated rats (k = 0.0048.h-1; r = 1.8 pmol.h-1/g protein), but the alteration of degradation rate constant missed significance (P > 0.05). As a result, receptor recovery following EEDQ was accelerated. The half time for D1 and D2 receptors recovery in SPD group were 117.5 h and 84.5 h, respectively, shorter than 144.4 h and 141.4 h in vehicle-treated rats. CONCLUSION: Chronic SPD treatment upregulated D1 and D2 receptors, and accelerated DA receptor turnover and recovery mainly by increasing receptor synthesis.

Effect of (-)-stepholidine on serum prolactin level of female rats.

AIM: To study the effect of (-)-stepholidine (SPD) on serum prolactin (PRL) level and elucidate its pharmacological action on dopamine D2 receptors. METHOD: After i.p. administration of dopamine receptor agonist, antagonist, or SPD, the serum PRL levels were determined by radioimmunoassay. RESULTS: SPD (24 mg.kg-1, i.p.) caused a rapid rise in serum PRL level, lasting more than 1 h. SPD 0.2-40 mg.kg-1 raised serum PRL level in a dose-dependent manner with ED50 of 3.7 mg.kg-1 (95% confidence limits, 2.6-4.3 mg.kg-1) and PRL maximal level of 448 +/- 64 micrograms.L-1. Pergolide 2 mg.kg-1 i.p. caused a decrease (P < 0.01 vs saline) of PRL level, which was partially attenuated by SPD of 5 mg.kg-1 and completely abolished by 10 mg.kg-1. CONCLUSION: SPD is a dopamine D2 receptor antagonist.

Enhancement of transcription termination factor rho activity with potassium glutamate.

The efficiencies of rho action as a termination factor during transcription in vitro of several DNA templates were determined as a function of the concentration and type of electrolyte ions. The termination efficiencies with lambda-tR1 and the promoter proximal lacZ intragenic terminators were significantly higher with 0.1-0.2 M potassium glutamate as the major electrolyte than with the optimal concentrations of KCl (approximately 0.05 M) or potassium acetate (approximately 0.15 M). Similar high efficiencies were obtained with salts of other acidic amino acids but not with a salt of N-acetylglutamic acid or with a mixture of 0.15 M potassium acetate and 0.15 M glycine, and termination was inhibited completely when 0.12 M KCl was present along with 0.12 M potassium glutamate. The salts that give high termination efficiencies have two properties in common; they consist of anions that are also zwitterions, and they are weak chelators of Mg2+ ions. The increase in termination efficiency with potassium glutamate can be ascribed mainly to a facilitation of the reactions of rho with RNA that are coupled to ATP hydrolysis, as the rate of ATP hydrolysis with isolated transcripts as cofactors was about five times higher with 0.15 M potassium glutamate than with 0.05 M KCl, whereas the rates of chain elongation, the general stability of the transcription complexes, and the binding affinity of rho with the transcripts were all very similar under the two conditions. Further analysis revealed that the activation of ATP hydrolysis is an outcome of a shift in the optimum magnesium salt concentration from 0.5 mM with 0.05 M KCl to 4 mM with 0.15 M potassium glutamate. Since glutamate is a relatively weak counterion for cationic groups in proteins, potassium glutamate can be used at 0.15 M without inhibiting the binding of rho to RNA. At that concentration, it serves to buffer the level of free Mg2+ available to stabilize RNA secondary structures that are known to impede rho action on RNA. The two special properties of glutamate together create conditions that allow rho to terminate transcription in vitro at an efficiency that matches the in vivo efficiency with use of a physiological level of K+ ions.