In Vitro Hypoglycemic Diterpenoids from the Roots of Croton yunnanensis

Fifteen compounds including nine new diterpenes were isolated from the roots of Croton yunnanensis. By HRESIMS, NMR, ECD data, and X-ray diffraction analysis, the new compounds were characterized as eight neo-clerodane diterpenes (compounds 1-8) and one 15,16-dinor-ent-pimarane diterpene (9). All diterpenes were assayed for their hypoglycemic activities. Compounds 1-4, 6, 7, and 10 promoted glucose uptake activity in insulin-resistant 3T3-L1 adipocytes. Compounds 1 and 6 showed insulin sensitizing activity, potentiating conspicuously their glucose uptake activity at a concentration of 20 μM when treated synergistically with low-concentration insulin at 1 nM.

[Analysis of the necessity of anticoagulation therapy and influencing factors of stent occlusion after transjugular intrahepatic portosystemic shunt]

Objective: To explore the necessity of anticoagulation therapy and influencing factors of stent occlusion after transjugular intrahepatic portosystemic shunt. Methods: The basic information, laboratory test results, preoperative portal venous pressure, postoperative anticoagulation time, postoperative stent stenosis or occlusion, followed-up and other data of all patients who underwent TIPS surgery in Shandong Provincial Hospital from 2010 to 2019 were retrospectively analyzed. Data were analyzed using t-test, χ² test, and multivariate analysis (logistic regression and Cox-regression-analysis). Results: A total of 280 cases were finally included in the study, of which 110 (39.3%) had stent stenosis or occlusion, and 170 (60.7%) had stent patency. New or worsening ascites were identified in 194 cases during the follow-up period, including 14 (31.1%) cases in the stent stenosis or occlusion group and 19 (12.8%) cases in the stent patency group. Univariate analysis showed that presence or absence of platelet (P=0.037) and total bilirubin (P=0.038) were correlated with stent stenosis or occlusion. Postoperative continuous anticoagulation was correlated with stent blockage (P=0.029) in patients with partial portal vein thrombosis. Postoperative continuous anticoagulation and stent occlusions were not significantly correlated in patients with preoperative portal cavernoma and preoperative portal vein patency (P=0.848; P=0.744). Multivariate analysis results showed that whether long-term anticoagulation (P=0.017), all-cause rebleeding (P<0.001), postoperative significant hepatic encephalopathy (P<0.012), and postoperative new or worsening ascites (P<0.001) was significantly associated with stent occlusion (P<0.05), while platelets (P=0.134), total bilirubin (P=0.229), international normalized ratio (P=0.436), and portal vein pressure (P=0.230) were not significantly associated with stent occlusion after surgery. Conclusion: In patients with partial portal vein thrombosis before surgery, continuous anticoagulation for 30 days post-TIPS therapy can effectively prevent stent stenosis or occlusion; while in patients with portal vein patency, portal cavernoma and complete portal vein blockage before surgery, postoperative anticoagulation has no significant effect on stent stenosis or occlusion.

Tigliane Diterpenoids with Larvicidal, Antifungal, and α-Glucosidase Inhibitory Activities from Croton damayeshu

Thirty-five tigliane diterpenoids and two ent-kaurane diterpenoids were isolated from the leaves of Croton damayeshu, and, among them, compounds 1-10 were characterized as new tigliane diterpenoids. The structures of compounds 1-10 were determined by analysis of their HRESIMS, NMR, and ECD data and by chemical methods. The isolates were assayed for their larvicidal, antifungal, and α-glucosidase inhibitory activities, and compounds 8-10 were found to possess larvicidal activities against Plutella xylostella with LC₅₀ values of 0.19, 0.16, and 0.26 μM, respectively, comparable to the LC₅₀ of 0.14 μM for the positive control, flubendiamide.

Association between ARNTL (BMAL1) rs2278749 polymorphism T >C and susceptibility to Alzheimer disease in a Chinese population

In the present study, we examined whether the ARNTL (BMAL1) rs2278749 T/C polymorphism was associated with the susceptibility to Alzheimer disease (AD). This case-control study examined the genotypes of apolipoprotein E (APOE e4) and BMAL1 rs2278749 T/C using restriction fragment length polymorphism and the TaqMan assay, respectively. A total of 296 unrelated AD patients and 423 control subjects were included. Both in the entire sample and in APOE e4 non-carriers, the prevalence of T carriers in BMAL1 rs2278749 T/C in AD patients was significantly higher than that in control subjects (entire sample: χ(2) = 12.950, P < 0.0001; APOE e4 non-carriers: χ(2) = 13.094, P < 0.0001). Both in the entire sample and in APOE e4 non-carriers, the prevalence of TT genotypes 2278749 in AD patients was also significantly higher than that in control subjects (entire sample: χ(2) = 7.765, P = 0.024; APOE e4 non-carriers: χ(2) = 13.062, P < 0.0001). However, among APOE e4 carriers, the difference in the prevalence of T carriers or TT genotypes in the BMAL1 rs2278749 T/C between patients and control subjects presents was not significant (T carriers: χ(2) = 0.078, P = 0.851 or TT genotypes: χ(2) = 2.576, P = 0.325). Among APOE e4 non-carriers, T carriers in the BMAL1 rs2278749 T/C were associated with a high susceptibility to AD, but among APOE e4 carriers, the association between AD and BMAL1 rs2278749 T/C was not significant.

Application of SRAP markers in the identification of Stylosanthes guianensis hybrids

Sequence-related amplified polymorphism (SRAP) is a new molecular marker technology developed based on polymerase chain reaction. The authenticity of 84 progenies of 8 hybrid combinations of Stylosanthes guianensis was identified by SRAP markers to select the true hybrids used in the present study. A total of 35 SRAP primer combinations were selected from the parents of 8 hybrid combinations. The selected polymorphism primer combinations were applied to identify the authenticity of all progenies. The male parents of the primer combinations had specific markers, whereas the female parents did not. 68 progenies exhibited male parent-specific bands, which were identified as true hybrids. The rest of the progenies were considered self-hybrids because of the absence of male parent-specific bands. The results of hybrid identification provided solid evidence for further studies of hybrids and demonstrated SRAP molecular markers as a useful technology for assessing the purity of S. guianensis hybrids.

PD plus error-dependent integral nonlinear controllers for robot manipulators with an uncertain Jacobian matrix

In framework of traditional PID controllers, there are only three parameters available to tune, as a result, performance of the resulting system is always limited. As for Cartesian regulation of robot manipulators with uncertain Jacobian matrix, a scheme of PID controllers with error-dependent integral action is proposed. Compare with traditional PID controllers, the error-dependent integration is employed in the proposed PID controller, in which more parameters are available to be tuned. It provides additional flexibility for controller characteristics and tuning as well, and hence makes better transient performance. In addition, asymptotic stability of the resulting closed-loop system is guaranteed. All signals in the system are bounded when exogenous disturbances and measurement noises are bounded. Numerical example demonstrates the superior transient performance of the proposed controller over the traditional one via Cartesian space set-point manipulation of two-link robotic manipulator.

The Relationship between Renal Injury and Change in Vitamin D Metabolism in Aged Rats with Insulin Resistance or Type 2 Diabetes Mellitus

Insulin resistance (IR), IR treated with vitamin D, IR treated with 1α-hydroxyvitamin D (1α-(OH)D), type 2 diabetes mellitus (T2DM), T2DM treated with vitamin D and T2DM treated with 1a-(OH)D were studied in animal models using aged Wistar rats. Glucose infusion rates and levels of urinary albumin (UA), serum 25-hydroxyvitamin D (25-(OH)D) and 1, 25-dihydroxyvitamin D (1, 25-(OH)2D) were measured. T2DM rats had higher UA than IR or normal rats, and levels of 25-(OH)D in all models were similar. IR rats had higher 1, 25-(OH)2D levels than T2DM rats, and had lower 1, 25-(OH)2D levels than normal rats. Treating IR or T2DM rats with vitamin D had no effect on 25-(OH)D or 1, 25-(OH)2D. Administration of 1α-(OH)D significantly increased 1, 25-(OH)2D in IR rats to above-normal levels, and significantly increased 1, 25-(OH)2D in T2DM rats to normal levels. In IR or T2DM, abnormal vitamin D metabolism is characterized by 1, 25-(OH)2D deficiency and is related to renal injury.

Direct identification of propargyl radical in combustion flames by vacuum ultraviolet photoionization mass spectrometry

We have developed an effusive laser photodissociation radical source, aiming for the production of vibrationally relaxed radicals. Employing this radical source, we have measured the vacuum ultraviolet (VUV) photoionization efficiency (PIE) spectrum of the propargyl radical (C(3)H(3)) formed by the 193 nm excimer laser photodissociation of propargyl chloride in the energy range of 8.5-9.9 eV using high-resolution (energy bandwidth = 1 meV) multibunch synchrotron radiation. The VUV-PIE spectrum of C(3)H(3) thus obtained is found to exhibit pronounced autoionization features, which are tentatively assigned as members of two vibrational progressions of C(3)H(3) in excited autoionizing Rydberg states. The ionization energy (IE = 8.674 +/- 0.001 eV) of C(3)H(3) determined by a small steplike feature resolved at the photoionization onset of the VUV-PIE spectrum is in excellent agreement with the IE value reported in a previous pulsed field ionization-photoelectron study. We have also calculated the Franck-Condon factors (FCFs) for the photoionization transitions C(3)H(3) (+)(X;nu(i),i = 1-12)<--C(3)H(3)(X). The comparison between the pattern of FCFs and the autoionization peaks resolved in the VUV-PIE spectrum of C(3)H(3) points to the conclusion that the resonance-enhanced autoionization mechanism is most likely responsible for the observation of pronounced autoionization features. We also present here the VUV-PIE spectra for the mass 39 ions observed in the VUV synchrotron-based photoionization mass spectrometric sampling of several premixed flames. The excellent agreement of the IE value and the pattern of autoionizing features of the VUV-PIE spectra observed in the photodissociation and flames studies has provided an unambiguous identification of the propargyl radical as an important intermediate in the premixed combustion flames. The discrepancy found between the PIE spectra obtained in flames and photodissociation at energies above the IE(C(3)H(3)) suggests that the PIE spectra obtained in flames might have contributions from the photoionization of vibrationally excited C(3)H(3) and/or the dissociative photoionization processes involving larger hydrocarbon species formed in flames.

Characterization of Fasciola samples from different host species and geographical localities in Spain by sequences of internal transcribed spacers of rDNA

In the present study, 25 samples representing Fasciola (Platyhelminthes: Trematoda: Digenea) from nine host species and 19 geographical locations in Spain were characterized genetically by sequences of the first (ITS-1) and second (ITS-2) internal transcribed spacers (ITS) of nuclear ribosomal DNA (rDNA). The ITS rDNA was amplified from individual liver flukes by polymerase chain reaction (PCR), and the amplicons were sequenced directly. The lengths of the ITS-1 and ITS-2 sequences were 422 and 362 bp, respectively, for all Spanish liver fluke samples sequenced. Comparison of the ITS sequences of the Spanish Fasciola samples examined in the present study with that of Fasciola hepatica, Fasciola gigantica and the "intermediate Fasciola" revealed that all Spanish Fasciola samples examined represent the single species of F. hepatica, with only slight sequence variation in the ITS-2 (1/362, 0.3%) among the sequenced samples, but the sequence variation was not related to particular host species and/or geographical origins of the samples. The Spanish F. hepatica examined differed from Fasciola from elsewhere by two nucleotides in the ITS-2, which provided genetic marker for the differentiation of Spanish F. hepatica from Fasciola from other geographical localities. These results have implications for studying the population genetic structure of the Spanish F. hepatica and for the diagnosis and control of the disease it causes.

Expression of testis specific ankyrin repeat and SOCS box-containing 17 gene

Human ASB-17 (Ankyrin Repeat and SOCS Box-containing 17) is a recently identified gene belonging to the ASB family, isolated from testis cDNA library. Human ASB-17 is expressed exclusively in testis among 16 tissues, revealed by Northern blot. Mouse Asb-17 was shown to be expressed from the third week post birth to adult by semi-quantitative RT-PCR analysis. In situ hybridization on frozen sections demonstrated that Asb-17 is expressed in spermatogenic cells in adult mouse, but not in Leydig cell and epididymis in adult mouse. ASB-17 proteins are highly conserved in mammals including human, mouse, rat, Canis familiaris and Macaca fascicularis.

1-Alkyl-3-amino-5-aryl-1H-[1,2,4]triazoles: novel synthesis via cyclization of N-acyl-S-methylisothioureas with alkylhydrazines and their potent corticotropin-releasing factor-1 (CRF(1)) receptor antagonist activities

Cyclizations of alkylhydrazines with N-acyl-S-methylisothioureas, readily synthesized from acyl chlorides, sodium thioisocyanate, dialkylamines then methyl iodide in a one-pot reaction, gave 1-alkyl-3-dialkylamino-5-phenyltriazoles 7 as major products. The regioisomers were assigned through the use of NOE NMR experiments. While bearing a N-bis(cyclopropyl)methyl-N-propylamino group, this series of compounds shows very good binding affinity on the human CRF(1) receptor. Among them, 1-methyl-3-[N-bis(cyclopropyl)methyl-N-propylamino]-5-(2,4-dichlorophenyl)-1H-[1,2,4]triazole 7a had the best binding affinity for the CRF(1) receptor (K(i)=9 nM).

Stimulus induced pH changes in cochlear implants: an in vitro and in vivo study

Large pH changes have been shown to be potentially harmful to tissue. The present study was designed to examine stimulus induced changes in pH for a variety of stimulus parameters both in vitro and in vivo, in order to ensure that stimulation strategies for neural prostheses result in minimal pH change. Stimulation using charge balanced biphasic pulses at intensities both within and well above maximum clinical levels for cochlear implants (0.025-0.68 microC per phase), were delivered to platinum electrodes in vitro [saline, phosphate buffered saline (PBS), or saline with human serum albumin (HSA)], and in vivo (scala tympani). Stimulus rates were typically varied from 62.5 to 1000 pulses per second (pps), although rates of up to 14,500 pps were used in some experiments. The pH level was recorded using a pH indicator (Phenol red) or pH microelectrodes. While electrical stimulation at intensities and rates used clinically showed no evidence of a pH shift, intensities significantly above these levels induced pH changes both in vitro and in vivo. The extent of pH change was related to stimulus rate and intensity. In addition, pH change was closely associated with the residual direct current (dc) level. As expected, stimulation with capacitive coupling induced little dc and a minimal pH shift. Moreover, no pH shift was observed using alternating leading phase pulse trains at intensities up to 0.68 microC per phase and 1000 pps. Saline with HSA or buffered solutions dramatically reduced the extent of pH shift observed following stimulation in unbuffered inorganic saline. Reduced pH shift was also observed following in vivo stimulation. These findings provide an insight into mechanisms of safe change injection in neural prostheses.

Reduction in excitability of the auditory nerve following electrical stimulation at high stimulus rates: V. Effects of electrode surface area

High rate intracochlear electrical stimulation at high intensities can induce significant reductions in the excitability of the auditory nerve as measured by a decrement in the amplitude of the electrically evoked auditory brainstem response (EABR). Such changes are primarily associated with stimulus induced neuronal activity, although direct current (DC) can also contribute. We examined the extent of stimulus induced change in auditory nerve excitability using large surface area platinum electrodes ('high-Q' electrodes). These electrodes have a surface area approximately 70 times greater than standard Pt electrodes of the same geometric area, resulting in lower DC and charge density (charge/electrode surface area) for a common stimulus. Guinea pigs were bilaterally implanted with either high-Q or standard Pt electrodes, and unilaterally stimulated for 2 h using stimulus intensities of 12 dB or 20-30 dB above EABR threshold (0.34 microC/phase) at stimulus rates of 200, 400, or 1000 pulses per second (pps). EABRs were recorded before and following the acute stimulation. While there were significant reductions in EABR amplitudes and elevated EABR thresholds following stimulation at 12 dB above threshold using 400 and 1000 pps delivered to standard Pt electrodes, there were fewer or no significant changes in the post-stimulus EABR amplitude and threshold using high-Q electrodes under equivalent stimulus conditions. At a higher stimulus intensity (20-30 dB above EABR threshold), no reduction in EABR amplitude was observed at 200 pps for both stimulating electrodes. However, EABRs were reduced significantly at 400 and 1000 pps. There was significantly greater EABR recovery following stimulation using high-Q electrodes compared with standard Pt electrodes at 400 (P<0.05) and 1000 pps (P<0.05). These data indicate that large surface area electrodes can significantly reduce stimulus induced changes in auditory nerve excitability, and may therefore have important clinical application.

Reduction in excitability of the auditory nerve following electrical stimulation at high stimulus rates. IV. Effects of stimulus intensity

High rate intracochlear electrical stimulation using stimulus intensities well above clinical limits can induce a significant reduction in the excitability of the auditory nerve as measured by a reduction in the amplitude of the electrically evoked auditory brainstem response (EABR). The purpose of the present study was to assess the effect of stimulus intensity on these stimulus induced changes by comparing the effects of acute stimulation using stimulus intensities within normal clinical levels (6 dB and 12 dB above EABR threshold) and significantly above normal clinical levels (> 20 dB above EABR threshold; 0.34 microC/phase). Stimulus rates of 200, 400, or 1000 pulses/s (pps) were delivered to bipolar scala tympani electrodes. EABRs were recorded before and periodically following 2 h of continuous stimulation. No reduction in EABR amplitude was observed following stimulation at 6 dB above EABR threshold for the three stimulus rates examined. However, EABRs were reduced when stimulated at 12 dB above EABR threshold at 400 pps, and significantly reduced when stimulated at a rate of 1000 pps. Immediate post-stimulus response amplitudes of wave III were 63% and 35% of the pre-stimulus amplitude at 400 and 1000 pps respectively. More significant reductions in EABR amplitude were observed following stimulation at levels more than 20 dB above EABR threshold for both 400 and 1000 pps stimuli. Our findings indicate that stimulus induced changes in EABR amplitude are related to both stimulus rate and stimulus intensity. Moreover, stimulation using intensities within the normal clinical range show little evidence of prolonged reductions in auditory nerve excitability at stimulus rates of up to 1000 pps.

Electrical stimulation of the auditory nerve: direct current measurement in vivo

Neural prostheses use charge recovery mechanisms to ensure the electrical stimulus is charge balanced. Nucleus cochlear implants short all stimulating electrodes between pulses in order to achieve charge balance, resulting in a small residual direct current (DC). In the present study we sought to characterize the variation of this residual DC with different charge recovery mechanisms, stimulation modes, and stimulation parameters, and by modeling, to gain insight into the underlying mechanisms. In an acute study with anaesthetised guinea pigs, DC was measured in four platinum intracochlear electrodes stimulated using a Nucleus C124M cochlear implant at moderate to high pulse rates (1200-14,500 pulses/s) and stimulus intensities (0.2-1.75 mA at 26-200 microseconds/phase). Both monopolar and bipolar stimulation modes were used, and the effects of shorting or combining a capacitor with shorting for charge recovery were investigated. Residual DC increased as a function of stimulus rate, stimulus intensity, and pulse width. DC was lower for monopolar than bipolar stimulation, and lower still with capacitively coupled monopolar stimulation. Our model suggests that residual DC is a consequence of Faradaic reactions which allow charge to leak through the electrode tissue interface. Such reactions and charge leakage are still present when capacitors are used to achieve charge recovery, but anodic and cathodic reactions are balanced in such a way that the net charge leakage is zero.

Reduction in excitability of the auditory nerve following acute electrical stimulation at high stimulus rates: III. Capacitive versus non-capacitive coupling of the stimulating electrodes

Safe electrical stimulation of neural tissue is typically achieved using charge-balanced biphasic current pulses, which are designed to minimize the generation of direct current (DC) and the production of harmful electrochemical products. However, due to the kinetics of the charge injection process, neural stimulators must also use capacitive coupling or electrode shorting techniques, to ensure DC levels are minimal. Previous studies have reported a reduction in excitability of the auditory nerve following acute simulation at high rates and intensities. Elevated levels of DC were reported in these studies despite using charge-balanced biphasic pulses and electrode shorting. The present study was designed to investigate the extent to which DC contributed to these stimulus induced reductions in auditory nerve excitability. Adult guinea pigs were bilaterally implanted and unilaterally stimulated for two hours using charge-balanced biphasic current pulses and stimulus rates of 200, 400 or 1000 pulses/s (pps) at a stimulus intensity well above clinical levels (0.34 microC/phase). DC levels were controlled using either electrode shorting, or electrode shorting with capacitive coupling. Electrically evoked auditory brainstem responses (EABRs) were recorded before and periodically following the acute stimulation. It was found that the extent of reduction in the EABR amplitude was a function of stimulus rate. While there was little change in the EABR following stimulation at 200 pps, significant post-stimulus reductions in the EABR amplitude were observed at stimulus rates of 400 and 1000 pps during the three hour post-stimulus monitoring period. Stimulation using capacitively coupled electrodes, which eliminated all DCs, showed reductions in EABR amplitudes similar to those observed following stimulation using electrode shorting alone. While there was no significant difference in the extent of reduction in EABR amplitudes for capacitive coupling versus electrode shorting at stimulus rates of 200 pps (P > 0.05) and 400 pps (P > 0.05), there was a significant difference at 1000 pps (P< 0.001). The present findings indicate that the major component of the stimulus induced reductions observed in auditory nerve excitability appear to be associated with stimulus induced neuronal activity, although elevated levels of DC ( > 2.5 microA) can also contribute to these changes. However, although statistically significant, the effects of DC are very small compared to the effects of high rate, high intensity stimulation per se.