The Effect of Dezocine on the Median Effective Dose of Sufentanil-Induced Respiratory Depression in Patients Undergoing Spinal Anesthesia Combined with Low-Dose Dexmedetomidine

Purpose

The application of sedation and analgesia in spinal anesthesia has many benefits, but the risk of respiratory depression (RD) caused by opioids cannot be ignored. We aimed to observe the effect of dezocine, a partial agonist of μ-receptor, on the median effective dose (ED50) of sufentanil-induced RD in patients undergoing spinal anesthesia combined with low-dose dexmedetomidine.

Patients and Methods

Sixty-two patients were randomly assigned to dezocine group (DS) and control group (MS). After spinal anesthesia, mask oxygen (5 L/min) and dexmedetomidine (0.1 ug/kg) were given. Five minutes later, patients in the DS group received an Intravenous (IV) bolus of sufentanil and 0.05mg/kg dezocine, while patients in the MS group only received an IV bolus of sufentanil.

Results

ED50 of DS group was 0.342 ug/kg, 95% confidence interval (CI) was (0.269, 0.623) ug/kg, and the ED50 of MS group was 0.291 ug/kg, 95% CI was (0.257, 0.346) ug/kg. There was no difference in the type and treatment measures of RD and hemodynamic changes between the two groups, and no serious adverse reactions occurred in either group.

Conclusion

Dezocine can improve RD induced by sufentanil in patients with spinal anesthesia combined with low-dose dexmedetomidine, and increase the safety window of sufentanil use.

Anti-hypertensive and endothelia protective effects of Fufang Qima capsule on primary hypertension via adiponectin/adenosine monophosphate activated protein kinase pathway

OBJECTIVE

To investigate the potential mechanism of the vascular remodeling effect and provide additional information about anti-hypertension activity of Fufang Qima capsule.

METHODS

Spontaneous hypertensive rats (SHRs) were used to study the underlying mechanism of the anti-hypertension activity of QM. In this study, SHRs were randomly divided into 5 groups: model group, Telmisartan group (7.2 mg/kg, p.o.), and three QM groups (0.9298, 1.8596, and 3.7192 g/kg, p.o.). Wistar Kyoto rats (WKY) were used as normal control group. Blood pressure (BP), aorta, perivascular adipose tissue (PVAT) histology were investigated to evaluate the effect of QM. Nitric oxide (NO) and endothelial nitric oxide synthase (eNOS) phosphorylation were measured. Adiponectin (APN) secretion, as well as APN signal pathway proteins including APN, adiponectin receptors (R1 and R2) and adenosine 5'-monophosphate-activated protein kinase (AMPK) were all analyzed.

RESULTS

QM significantly reduced BP and ameliorated the vascular pathological change, i.e. intima media thicken and collagen fiber hyperplasia. Meanwhile, QM increased concentration of NO and the phosphorylation of eNOS in the aorta. The anti-hypertensive and endothelia-protective effect of QM could be attributed to activating APN/ AMPK pathway by up-regulating the expression of APN in PVAT and APN Receptor 2, AMPKα and phosphorylated AMPKα in the aorta.

CONCLUSION

The QM alleviation effect mechanism for primary hypertension was via modulating the APN/AMPK signal pathway.

Can machine learning-based analysis of multiparameter MRI and clinical parameters improve the performance of clinically significant prostate cancer diagnosis?

Purpose

To establish machine learning(ML) models for the diagnosis of clinically significant prostate cancer (csPC) using multiparameter magnetic resonance imaging (mpMRI), texture analysis (TA), dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) quantitative analysis and clinical parameters and to evaluate the stability of these models in internal and temporal validation.

Methods

The dataset of 194 men was split into training (n = 135) and internal validation (n = 59) cohorts, and a temporal dataset (n = 58) was used for evaluation. The lesions with Gleason score ≥ 7 were defined as csPC. Logistic regression (LR), stepwise regression (SR), classical decision tree (cDT), conditional inference tree (CIT), random forest (RF) and support vector machine (SVM) models were established by combining mpMRI-TA, DCE-MRI and clinical parameters and validated by internal and temporal validation using the receiver operating characteristic (ROC) curve and Delong’s method.

Results

Eight variables were determined as important predictors for csPC, with the first three related to texture features derived from the apparent diffusion coefficient (ADC) mapping. RF, LR and SR models yielded larger and more stable area under the ROC curve values (AUCs) than other models. In the temporal validation, the sensitivity was lower than that of the internal validation (p < 0.05). There were no significant differences in specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV) and AUC (p > 0.05).

Conclusions

Each machine learning model in this study has good classification ability for csPC. Compared with internal validation, the sensitivity of each machine learning model in temporal validation was reduced, but the specificity, accuracy, PPV, NPV and AUCs remained stable at a good level. The RF, LR and SR models have better classification performance in the imaging-based diagnosis of csPC, and ADC texture-related parameters are of the highest importance.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11548-021-02507-w.

First-line Daratumumab in Addition to Chemotherapy for Newly Diagnosed Multiple Myeloma Patients Who are Transplant Ineligible: A Cost-Effectiveness Analysis

PURPOSE

Daratumumab is a standard-of-care treatment for newly diagnosed multiple myeloma (NDMM). According to the ALCYONE trial, the addition of daratumumab to bortezomib, melphalan, and prednisone (D-VMP) provides significantly longer overall survival and progression-free survival than bortezomib, melphalan, and prednisone (VMP) in patients with NDMM. However, considering the high price of daratumumab, it is necessary to conduct further research on its efficacy and cost. This study evaluated the cost-effectiveness, from the US payer perspective, of D-VMP vs VMP in the first-line setting for patients with NDMM who are not eligible for autologous stem cell transplantation.

METHODS

A Markov model was developed to estimate the lifetime cost and effectiveness of VMP with or without daratumumab as the first-line therapy for patients with NDMM. Univariable sensitivity analysis and probabilistic sensitivity analysis were performed to address the model robustness and uncertainty. Expected value of perfect information analysis was conducted to explore the uncertainty of decision-making and future costs.

FINDINGS

D-VMP provides an additional 2.417 quality-adjusted life years (QALYs), at a cost of $30,893 per QALY. Sensitivity analysis revealed that the transition probability of progression-free survival in D-VMP strategy, the price of daratumumab, and body weight of the patient influenced the model results most strongly. Probabilistic sensitivity analysis showed that D-VMP versus VMP has a 90.8% probability of being cost-effective at the $150,000/QALY willingness-to-pay (WTP) threshold. The population expected value of perfect information was $2150 million at a WTP threshold of $50,000/QALY and $1481 million at $100,000/QALY.

IMPLICATIONS

In this study, D-VMP was estimated to be cost-effective compared with VMP for patients with NDMM at a WTP threshold of $150,000/QALY. (Clin Ther. 2021;43:XXX-XXX) © 2021 Elsevier HS Journals, Inc.

[Effectiveness of the "14 plus 7 day quarantine" and "nucleic acid plus total antibody testing" strategy for screening imported patients with COVID-19 in Xiamen]

Objective: To analysis effectiveness of the "14 plus 7 day quarantine" and "nucleic acid plus total antibody testing" strategy (combined screening strategy) for screenin the imported patients with COVID-19 in Xiamen. Methods: The study populations were overseas travelers arriving in Xiamen from March 17 to December 31, 2020, and overseas travelers who had quarantine outside Xiamen for less than 21 days from July 18 to December 31, 2020. Data were collected and analyzed on the timing of detection, pathways, and test results of the imported patients with COVID-19 after implementing combined screening strategy. Results: A total of 304 imported patients with COVID-19 were found from 174 628 overseas travelers and 943 overseas travelers from other cities. A total of 163 cases (53.6%) were diagnosed by multitime, multisite intensive nucleic acid testing after positive finding in total antibody testing. Among them, 27 (8.9%) were first positive for nucleic acid in 14 plus 7 day quarantine and 136 were first positive for nucleic acid in 14-day quarantine. Only 8 of these individuals were tested positive for nucleic acid after positive total antibody testing. The other 128 individuals were tested positive for nucleic acid after being negative for average 2.3 times (maximum of 6 times). Aditional 155 cases might be detected by using the combined "14 plus 7 day quarantine" and " nucleic acid plus total antibody testing" strategy compared with "14-day quarantine and nucleic acid testing" strategy, accounting for 51.0% of the total inbound infections. So the combined screening strategy doubled the detection rate for imported patients with COVID-19. No second-generation case caused by overseas travelers had been reported in Xiamen as of February 26, 2021. Conclusions: Xiamen's combined screening strategy can effectively screen the imported patients with COVID-19 who were first positive for nucleic acid after 14 day quarantine. Compared with "14 day quarantine and nucleic acid testing", the combined screening strategy improved detection rate and further reduced the risk of the secondary transmission caused by the imported patients with COVID-19.

Sacubitril/valsartan treatment relieved the progression of established pulmonary hypertension in rat model and its mechanism

AIMS

Pulmonary hypertension (PH) is a fatal disease identified by progressive elevated pulmonary arterial pressure, which neurohormonal activation is a notable contributor to its development. Sacubitril/valsartan is a complex of sacubitril [via enhancing the natriuretic peptide (NP) system] and valsartan [via blocking the renin-angiotensin-aldosterone system (RAAS)]. Regulation of the two neurohormonal system had been shown to attenuate PH. This study was to explore the role of sacubitril/valsartan in both monocrotaline (MCT)-induced and hypoxia-induced rat models and the underlying mechanism.

MAIN METHODS

The rats were treated with MCT or hypoxic environment for 14 days, after that sacubitril/valsartan were given for another 14 days. Hemodynamic measurements and histological assessments were performed. The expression of NPs was measured using RT-PCR and ELISA, while the protein level of natriuretic peptide receptors (NPRs) and AT1 receptor were detected by western blot, the concentrations of cGMP, IL-1β, IL-6, TNF-α and TGF-β1 were tested by ELISA.

KEY FINDINGS

We found that sacubitril/valsartan significantly improved the hemodynamic and histological data of two PH models. Sacubitril/valsartan suppressed the protein expression of AT1 receptor (P < 0.05). The intervention increased the expression of ANP and CNP (P< 0.05) and therefore upregulated the protein expression of NPRs (P < 0.05), raised the concentration of cGMP (P < 0.05). In addition, the treatment reduced the concentration of IL-1β, IL-6 and TNF-α (P < 0.05) but have no effects on TGF-β1.

SIGNIFICANCE

Sacubitril/valsartan alleviated PH in MCT-induced and hypoxia-induced rat models by inhibiting the activated RAAS, promoting ANP/NPR-A/cGMP and CNP/NPR-B/cGMP pathway, restoring the NPR-C signaling and the anti-inflammatory effects.

First-line Nivolumab Plus Ipilimumab vs Sunitinib for Metastatic Renal Cell Carcinoma: A Cost-effectiveness Analysis

Importance

Recently, new drugs have been approved for the first-line treatment of metastatic renal cell carcinoma (mRCC). Nivolumab plus ipilimumab significantly increases overall survival for intermediate- and poor-risk patients with mRCC. However, considering the high cost of nivolumab plus ipilimumab, there is a need to assess its value by considering both efficacy and cost.

Objective

To evaluate the cost-effectiveness of nivolumab plus ipilimumab vs sunitinib in the first-line setting for intermediate- and poor-risk patients with mRCC from the US payer perspective.

Design, Setting, and Participants

A Markov model was developed to compare the lifetime cost and effectiveness of nivolumab plus ipilimumab vs sunitinib in the first-line treatment of mRCC using outcomes data from the CheckMate 214 phase 3 randomized clinical trial, which included 1096 patients with mRCC (median age, 62 years) and compared nivolumab plus ipilimumab vs sunitinib as first-line treatment of mRCC. In the analysis, patients were modeled to receive sunitinib or nivolumab plus ipilimumab for 4 doses followed by nivolumab monotherapy.

Main Outcomes and Measures

Life-years, quality-adjusted life-years (QALYs), and lifetime costs were estimated, at a willingness-to-pay threshold of $100 000 to $150 000 per QALY. Univariable, 2-way, and probabilistic sensitivity analyses were performed to evaluate the model uncertainty. Additional subgroup analyses were performed.

Results

Nivolumab plus ipilimumab provided an additional 0.96 QALYs, at a cost of $108 363 per QALY. Sensitivity analyses found the results to be most sensitive to overall survival hazard ratio (0.63; 95% CI, 0.44-0.89) and mean patient weight (70 kg, range, 40-200 kg). Other variables, such as the cost of nivolumab plus ipilimumab (mean, $32 213.44; range, $25 770.75-$38 656.13), utility values for nivolumab plus ipilimumab (mean, 0.82; range, 0.65-0.98), and proportion receiving nivolumab in sunitinib arm (mean, 0.27; range, 0.22-0.32), had a moderate or minor influence on model results. Subgroup analyses demonstrated that nivolumab plus ipilimumab was most cost-effective for patients with programmed cell death 1 ligand 1 expression of at least 1% ($86 390 per QALY).

Conclusions and Relevance

In this model, nivolumab plus ipilimumab was estimated to be cost-effective compared with sunitinib for intermediate- and poor-risk patients with mRCC at a willingness-to-pay threshold from $100 000 to $150 000 per QALY.

Search for Light Weakly-Interacting-Massive-Particle Dark Matter by Annual Modulation Analysis with a Point-Contact Germanium Detector at the China Jinping Underground Laboratory

We present results on light weakly interacting massive particle (WIMP) searches with annual modulation (AM) analysis on data from a 1-kg mass p-type point-contact germanium detector of the CDEX-1B experiment at the China Jinping Underground Laboratory. Datasets with a total live time of 3.2 yr within a 4.2-yr span are analyzed with analysis threshold of 250 eVee. Limits on WIMP-nucleus (χ-N) spin-independent cross sections as function of WIMP mass (m_{χ}) at 90% confidence level (C.L.) are derived using the dark matter halo model. Within the context of the standard halo model, the 90% C.L. allowed regions implied by the DAMA/LIBRA and CoGeNT AM-based analysis are excluded at >99.99% and 98% C.L., respectively. These results correspond to the best sensitivity at m_{χ}<6  GeV/c^{2} among WIMP AM measurements to date.

Mechanism of YLTZ on glycolipid metabolism based on UPLC/TOF/MS metabolomics

Type 2 diabetes mellitus (T2DM) is a metabolic disease characterized by dysfunction of glycolipid metabolism. YLTZ is used to treat hyperlipidemia, yet its hypolipidemic and hypoglycemic mechanism on T2DM are unknown. Thus, UPLC/TOF/MS was applied in this study to identify the potential bio-markers, and deduce the possible metabolic pathways. According to bio-indexes, the increased blood lipid levels, including TC, TG, LDL and FA, and the decreased HDL, the elevated glucose, reduced insulin level and impaired OGTT were observed in diabetic rat model. While YLTZ can decrease the lipid levels and glucose content, as well as increased insulin standards and improve OGTT. After data from UPLC/TOF/MS processed, 17 metabolites were obtained, including phospholipids (LPCs, PCs and PGP (18:1)), beta-oxidation production (HAA, VAG and CNE) and precursors (THA), bile acid (CA, CDCA and IDCA), hydrolysate of TG (MG (22:4)), glycometabolism (G6P), cholesterol-driven synthetics (ADO) and production of arachidonate acid (THETA). As a result, YLTZ was able to reduce LPCs, PCs, PGP (18:1), HAA, VAG, CNE, CA, ADO and THETA, as well as enhance MG (22:4) and G6P. After analyzing results, several metabolic pathways were deduced, which containing, cholesterol synthesis and elimination, FA beta-oxidation, TG hydrolysis, phospholipids synthesis, glycolysis, gluconeogenesis and inflammation. Consequently, YLTZ performed to prohibit the FA beta-oxidation, synthesis of cholesterol and phospholipids, gluconeogenesis and inflammation level, as well as promote TG hydrolysis, glycolysis and blood circulation. Hence, applying metabonomics in TCM research can uncover its pharmacological edges, elucidating comprehensively that YLTZ has capacity of hypolipidemic, hypoglycemic and promoting blood circulation, matching the effect of removing blood stasis, eliminating phlegm and dampness.

Limits on Light Weakly Interacting Massive Particles from the First 102.8 kg×day Data of the CDEX-10 Experiment

We report the first results of a light weakly interacting massive particles (WIMPs) search from the CDEX-10 experiment with a 10 kg germanium detector array immersed in liquid nitrogen at the China Jinping Underground Laboratory with a physics data size of 102.8 kg day. At an analysis threshold of 160 eVee, improved limits of 8×10^{-42} and 3×10^{-36}  cm^{2} at a 90% confidence level on spin-independent and spin-dependent WIMP-nucleon cross sections, respectively, at a WIMP mass (m_{χ}) of 5  GeV/c^{2} are achieved. The lower reach of m_{χ} is extended to 2  GeV/c^{2}.

RNA interference of GluN1 inhibits neuronal rhythmogenesis in the adult inferior olive

RNA interference (RNAi) to knockdown N-methyl-D-aspartate receptor (NMDAR) function is being investigated to address disorders associated with pathological brain rhythms. A motivating finding has been that pharmacological block of NMDARs inhibited oscillations in neuronal membrane potential that entrain rhythmic bursts of action potentials. To determine whether transient effects of NMDAR antagonist drugs to inhibit neuronal rhythmicity can be stably induced with genetic specificity, we examined the effects of RNAi of GluN1 protein on the subthreshold oscillations (STOs) of neurons in the inferior olive (IO), a pacemaking nucleus necessary for motor and cognitive timing. Western blot of dissociated neurons demonstrated 90% knockdown of GluN1 after a strong in vivo transduction by a dual-microRNA lentiviral vector. GluN1 RNAi in whole-cell-patched IO neurons blocked both membrane depolarization and STOs typically induced by NMDAR activation for up to 54 days without affecting input resistance, membrane capacitance, action potential firing, high-threshold Ca(2+) spikes, the hyperpolarization-activated current Ih, or the activation of the low-threshold Ca(2+) current I(T). Although an off-target effect on Cav3 expression was ruled out also by BlastN query, we found that GluN1 RNAi chronically eliminated I(T)-dependent STOs at resting membrane potential, well below the activation threshold of the NMDAR channel. In the context of a recent report showing that NMDAR activation induces STOs as it strengthens electrical coupling, the long-term block of STOs by GluN1 RNAi may relate to the loss of an essential support mechanism. Lentivector-mediated RNAi of GluN1 provides a novel technique for future investigations of NMDAR involvement in electrical oscillations and behavior.

NMDA receptor activation strengthens weak electrical coupling in mammalian brain

Electrical synapses are formed by gap junctions and permit electrical coupling, which shapes the synchrony of neuronal ensembles. Here, we provide a direct demonstration of receptor-mediated strengthening of electrical coupling in mammalian brain. Electrical coupling in the inferior olive of rats was strengthened by activation of NMDA-type glutamate receptors (NMDARs), which were found at synaptic loci and at extrasynaptic loci 20-100 nm proximal to gap junctions. Electrical coupling was strengthened by pharmacological and synaptic activation of NMDARs, whereas costimulation of ionotropic non-NMDAR glutamate receptors transiently antagonized the effect of NMDAR activation. NMDAR-dependent strengthening (1) occurred despite increased input conductance, (2) induced Ca(2+)-influx microdomains near dendritic spines, (3) required activation of the Ca(2+)/calmodulin-dependent protein-kinase II, (4) was restricted to neurons that were weakly coupled, and (5) thus strengthened coupling, mainly between nonadjacent neurons. This provided a mechanism to expand the synchronization of rhythmic membrane potential oscillations by chemical neurotransmitter input.

Spatially controlled synthesis of silver nanoparticles and nanowires by photosensitized reduction

The present paper reports on the spatially controlled synthesis of silver nanoparticles (NPs) and silver nanowires by photosensitized reduction. In a first approach, direct photogeneration of silver NPs at the end of an optical fiber was carried out. Control of both size and density of silver NPs was possible by changing the photonic conditions. In a further development, a photochemically assisted procedure allowing silver to be deposited at the surface of a polymer microtip was implemented. Finally, polymer tips terminated by silver nanowires were fabricated by simultaneous photopolymerization and silver photoreduction. The silver NPs were characterized by UV-visible spectroscopy and scanning electron microscopy.

[Expression of NK cells receptor NKG2D from peripheral blood in patients with primary hepatic carcinoma and its clinical significance]

OBJECTIVE

To investigate the expression of NK cells receptor NKG2D from peripheral blood in patients with primary hepatic carcinoma and the relationship between NKG2D expression and cytotoxicity of NK cells.

METHODS

Flow cytometry was used to determine the number of NK cells and the expression of NK cells receptor NKG2D from peripheral blood in patients with primary hepatic carcinoma (20 cases), hepatitis B cirrhosis (23 cases), hepatitis B (20 cases) and healthy control (20 cases). The microplate reader was used to detect cytotoxicity of NK cells in all cases.

RESULTS

Among killing rate of NK cell for K562 cell, the expression rate of NKG2D in NK cells, the number of NKG2D(+)NK cells, NKG2D expression level of NK cells and the number of NK cells, the liver cancer group [(25 +/- 7)%, 6%, 0.7 x 10(7)/L, 15, (1.1 +/- 0.6) x 10(8)/L] decreased significantly as compared with the healthy group [(63 +/- 7)%, 36%, 8.3 x 10(7)/L, 116, (2.7 +/- 1.1) x 10(8)/L] and the hepatitis B group [(41 +/- 8)%, 16%, 2.8 x 10(7)/L, 49, (1.9 +/- 1.1) x 10(8)/L] (P < 0.05); and there was a slight decrease as compared with the hepatitis B cirrhosis group [(29 +/- 10)%, 7%, 0.6 x 10(7)/L, 29, (1.5 +/- 1.2) x 10(8)/L] (all P > 0.05 except NKG2D expression level of NK cells P < 0.05). The activity of NK cells showed a obvious positive correlation with the number of NK cell and the positive rate of NKG2D in NK cells, the number of NKG2D(+)NK cells and NKG2D expression level of NK cells (r = 0.657, 0.770, 0.927, 0.734, all P < 0.01).

CONCLUSION

The cytotoxicity and the NKG2D expression of NK cells decreased significantly from peripheral blood in patients with primary hepatic carcinoma. The activity of NK cells was closely related to the NKG2D expression level of NK cells. Enhancing the NKG2D expression level of NK cell may provide a new idea for adoptive immunotherapy of primary hepatic carcinoma.

Normal motor learning during pharmacological prevention of Purkinje cell long-term depression

Systemic delivery of (1R-1-benzo thiophen-5-yl-2[2-diethylamino)-ethoxy] ethanol hydrochloride (T-588) prevented long-term depression (LTD) of the parallel fiber (PF)-Purkinje cell (PC) synapse induced by conjunctive climbing fiber and PF stimulation in vivo. However, similar concentrations of T-588 in the brains of behaving mice and rats affected neither motor learning in the rotorod test nor the learning of motor timing during classical conditioning of the eyeblink reflex. Rats given doses of T-588 that prevented PF-PC LTD were as proficient as controls in learning to adapt the timing of their conditioned eyeblink response to a 150- or 350-ms change in the timing of the paradigm. The experiment indicates that PF-PC LTD under control of the climbing fibers is not required for general motor adaptation or the learning of response timing in two common models of motor learning for which the cerebellum has been implicated. Alternative mechanisms for motor timing and possible functions for LTD in protection from excitotoxicity are discussed.

Fundamental role of inferior olive connexin 36 in muscle coherence during tremor

Inferior olive (IO) neurons are electrically coupled by cytosolic pores formed by the neuron-specific connexin 36 (Cx36). Electrical coupling in the IO figures prominently in current views about brain control of movement. However, a role for Cx36 in movement has been questioned and not definitively demonstrated. Previous reports have shown that embryonic deletion of the Cx36 gene resulted in almost complete loss of cytosolic and electrical coupling in the IO without an obvious deficit in movement, possibly due to developmental compensations in ionic conductances that can confound the approach of embryonic gene deletion. We used a replication-incompetent lentiviral vector to stably express a dominant-negative Cx36 mutant in the IO of adult rats. We show that interneuronal cytosolic coupling is severely reduced by the mutant Cx36, without effect on neuron morphology or electrical properties. Multisite electromyography revealed that blocking Cx36 in the IO impaired the coherence of muscle firing during harmaline tremor without affecting its rhythm. The data demonstrate that gap junction coupling within the IO mediated by Cx36 adds 10-20 ms of precision to the fine temporal coordination of muscle firing during movement.

Fundamental role of inferior olive connexin 36 in muscle coherence during tremor

Inferior olive (IO) neurons are electrically coupled by cytosolic pores formed by the neuron-specific connexin 36 (Cx36). Electrical coupling in the IO figures prominently in current views about brain control of movement. However, a role for Cx36 in movement has been questioned and not definitively demonstrated. Previous reports have shown that embryonic deletion of the Cx36 gene resulted in almost complete loss of cytosolic and electrical coupling in the IO without an obvious deficit in movement, possibly due to developmental compensations in ionic conductances that can confound the approach of embryonic gene deletion. We used a replication-incompetent lentiviral vector to stably express a dominant-negative Cx36 mutant in the IO of adult rats. We show that interneuronal cytosolic coupling is severely reduced by the mutant Cx36, without effect on neuron morphology or electrical properties. Multisite electromyography revealed that blocking Cx36 in the IO impaired the coherence of muscle firing during harmaline tremor without affecting its rhythm. The data demonstrate that gap junction coupling within the IO mediated by Cx36 adds 10-20 ms of precision to the fine temporal coordination of muscle firing during movement.

Insufficient processing resources in Parkinson's disease: evaluation using multimodal event-related potentials paradigm

The purpose of our study was to demonstrate impaired allocation of processing resources in non-demented patients with early-stage mild Parkinson's disease (PD) using a multimodal event-related potential (ERP) paradigm. The multimodal ERP paradigm was performed in 18 non-demented medicated patients with early-stage PD (Mini-Mental State Examination Score >26) and 16 matched normal controls, the Global Field Power (GFP) was employed for ERP components analysis, and the new modified Wisconsin Card Sorting Test (WCST) was used to evaluate frontal lobe function. Patients with PD did not exhibit novelty P3s, and P3 latency to non-target novel stimuli in visual and auditory modalities was significantly longer in PD patients than in controls. P3 amplitude for the target stimuli (P3b) was higher in PD in both auditory and visual modalities; however, P3b latency was not different between the two groups. Patients with PD showed a significantly lower score of achieved categories and made more perseverative errors in WCST as compared to controls. Our results showed that there were no natural novelty P3s in patients with PD; this finding suggests that non-demented patients with mild PD do not have sufficient mental resources to allocate to the central executive, due to dysfunction of the frontal lobe.

Inactivation of BK channels mediated by the NH(2) terminus of the beta3b auxiliary subunit involves a two-step mechanism: possible separation of binding and blockade

A family of auxiliary beta subunits coassemble with Slo alpha subunit to form Ca(2)+-regulated, voltage-activated BK-type K(+) channels. The beta subunits play an important role in regulating the functional properties of the resulting channel protein, including apparent Ca(2)+ dependence and inactivation. The beta3b auxiliary subunit, when coexpressed with the Slo alpha subunit, results in a particularly rapid ( approximately 1 ms), but incomplete inactivation, mediated by the cytosolic NH(2) terminus of the beta3b subunit (Xia et al. 2000). Here, we evaluate whether a simple block of the open channel by the NH(2)-terminal domain accounts for the inactivation mechanism. Analysis of the onset of block, recovery from block, time-dependent changes in the shape of instantaneous current-voltage curves, and properties of deactivation tails suggest that a simple, one step blocking reaction is insufficient to explain the observed currents. Rather, blockade can be largely accounted for by a two-step blocking mechanism (C(n) <---> O(n) <---> O(*)(n) <---> I(n)) in which preblocked open states (O*(n)) precede blocked states (I(n)). The transitions between O* and I are exceedingly rapid accounting for an almost instantaneous block or unblock of open channels observed with changes in potential. However, the macroscopic current relaxations are determined primarily by slower transitions between O and O*. We propose that the O to O* transition corresponds to binding of the NH(2)-terminal inactivation domain to a receptor site. Blockade of current subsequently reflects either additional movement of the NH(2)-terminal domain into a position that hinders ion permeation or a gating transition to a closed state induced by binding of the NH(2) terminus.

Abnormal information processing in dementia of Alzheimer type. A study using the event-related potential's field

Electrical field changes of event-related potentials (ERPs) were investigated in 26 patients with dementia of Alzheimer's type (DAT) and 12 age-matched normal subjects. The patients were assessed with the Clinical Dementia Rating and Mini-Mental State. Each patient selected had only mild to moderate mental disability. Auditory oddball stimulation was presented at 1.5 s intervals and 1,000 Hz for the nontarget and 2,000 Hz for the target tones, both at 85 dB. The target tones were 20% of all the tones. The reference-independent data (latency, global field power: GFP, dissimilarity index: DISS and location of centroids) were obtained and analyzed for each ERP component. The momentary electric strength or 'hilliness' of the ERPs landscape was indicated by GFP. The patients showed prolonged latencies and decreased P300 GFP amplitudes and of N100 GFP. These findings suggest that the abnormal electrical field of ERP may reflect abnormal information processing following the attentional process for target stimuli in DAT patients.

Rectification and rapid activation at low Ca2+ of Ca2+-activated, voltage-dependent BK currents: consequences of rapid inactivation by a novel beta subunit

A family of accessory beta subunits significantly contributes to the functional diversity of large-conductance, Ca(2+)- and voltage-dependent potassium (BK) channels in native cells. Here we describe the functional properties of one variant of the beta subunit family, which confers properties on BK channels totally unlike any that have as yet been observed. Coexpression of this subunit (termed beta3) with Slo alpha subunits results in rectifying outward currents and, at more positive potentials, rapidly inactivating ( approximately 1 msec) currents. The underlying rapid inactivation process results in an increase in the apparent activation rate of macroscopic currents, which is coupled with a shift in the activation range of the currents at low Ca(2+). As a consequence, the currents exhibit more rapid activation at low Ca(2+) relative to any other BK channel subunit combinations that have been examined. In part because of the rapid inactivation process, single channel openings are exceedingly brief. Although variance analysis suggests a conductance in excess of 160 pS, fully resolved single channel openings are not observed. The inactivation process results from a cytosolic N-terminal domain of the beta3 subunit, whereas an extended C-terminal domain does not participate in the inactivation process. Thus, the beta3 subunit appears to use a rapid inactivation mechanism to produce a current with a relatively rapid apparent activation time course at low Ca(2+). The beta3 subunit is a compelling example of how the beta subunit family can finely tune the gating properties of Ca(2+)- and voltage-dependent BK channels.

[Ion channels in rat pancreatic beta cells]

Using perforated and cell-attached patch clamp techniques, the characteristics of ATP sensitive K(+) channels (K(ATP)), delayed rectifier K(+) channels (K(DR)), Ca(2+) and Na+ channels on single rat pancreatic beta cell membranes were studied. The results showed that (1) the efflux and influx conductance of K(ATP) channels was about 31 and 65 pS respectively, and the reversal potential of K(ATP) was about 60 mV; (2) K(DR) was activated completely after a latency of 20 ms, and K(DR) was about 1/3 of K(ATP); (3) whole cell Ca(2+) current reached a peak (40 60 pA) at 0 mV; L-type Ca(2+) channel was the main Ca(2+) channel in beta cells, but other types of high voltage activated Ca(2+) channels existed as well; and 4) whole cell Na(+) current reached a peak (200 400 pA) at 10 mV; but the expression level of Na(+) channel in beta cells varied among the cells. About half of the beta cells virtually had no Na(+) currents.

[Role of M-type receptor in internal calcium release and quantal secretion in rat adrenal chromaffin cells]

In rat single adrenal chromaffin cells, the effects of methacholine (MCh) on [Ca2+]i and catecholamine secretion were studied with fura-2 fluorescence and carbon fiber electrodes. In the presence of 2 mmol/L Ca2+ in the bath, locally applying 1 mmol/L MCh, either containing or not containing Ca2+, evoked both [Ca2+]i and secretion signals. In the absence of Ca2+ in the bath, MCh could still evoke [Ca2+]i and secretion. These results suggest that MCh causes release of Ca2+ from Ca2+ stores, which is sufficient to yield the evoked secretion. The Ca2+ store can be depleted by single MCh puff in the absence of Ca2+ in the bath.