Aggregation-induced emission-active iridium (III)-based mitochondria-targeting nanoparticle for two-photon imaging-guided photodynamic therapy.

The efficacy of imaging-guided photodynamic therapy (PDT) is compromised by the attenuation of fluorescence and decline in reactive oxygen species (ROS) generation efficiency in the physiological environment of conventional photosensitizers, limited near-infrared (NIR) absorption, and high systemic cytotoxicity. This paper presents the synthesis of two cyclometalated Ir (III) complexes (Ir-thpy and Ir-ppy) by using a triphenylamine derivative (DPTPA) as the primary ligand and their encapsulation into an amphiphilic phospholipid to form nanoparticles (NPs). These complexes exhibit aggregation-induced emission features and remarkably enhanced ROS generation compared to Chlorin e6 (Ce6). Moreover, Ir-thpy NPs possess the unique ability to selectively target mitochondria, leading to depolarization of the mitochondrial membrane potential and ultimately triggering apoptosis. Notably, Ir-thpy NPs exhibit exceptional photocytotoxicity even towards cisplatin-resistant A549/DDP tumor cells. In vivo two-photon imaging verified the robust tumor-targeting efficacy of Ir-thpy NPs. The in vivo results unequivocally demonstrate that Ir-thpy NPs exhibit excellent tumor ablation along with remarkable biocompatibility. This study presents a promising approach for the development of multifunctional Ir-NPs for two-photon imaging-guided PDT and provides novel insights for potential clinical applications in oncology.

[Retracted] TRIM16 suppresses the progression of prostate tumors by inhibiting the Snail signaling pathway.

Following the publication of this paper, it was drawn to the Editor's attention by concerned readers that the western blotting data shown in Figs. 4C and 7B and D, the scratch­wound assay images shown in Figs. 5A and 6A, and certain of the cell migration and invasion assay data shown in Figs. 5B and 6B were strikingly similar to data that had previously appeared in different form in other articles by different authors. Owing to the fact that the contentious data in the above article had already been published elsewhere, or were already under consideration for publication, prior to its submission to International Journal of Molecular Medicine, the Editor has decided that this paper should be retracted from the Journal. After having been in contact with the authors, they accepted the decision to retract the paper. The Editor apologizes to the readership for any inconvenience caused. [International Journal of Molecular Medicine 38: 1734­1742, 2016; DOI: 10.3892/ijmm.2016.2774].

Serum Raman spectroscopy combined with convolutional neural network for rapid diagnosis of HER2-positive and triple-negative breast cancer.

Breast cancer is common in women, and its number of patients ranks first among female malignant tumors. Breast cancer is highly heterogeneous, and different types of breast cancer have different biological behaviors and prognoses. Therefore, identifying the different types of breast cancer is of great help in formulating individualized treatment plans. Based on serum Raman spectroscopy and deep learning algorithms, we propose a fast and low-cost diagnosis method for screening triple-negative breast cancer, human epidermal growth factor receptor 2 (HER2)-positive breast cancer, and healthy controls. We collected 75 serum samples in this study, including 23 triple-negative breast cancers, 22 HER2-positive breast cancers, and 30 healthy controls. Using the preprocessed Raman spectra as the input of deep learning, three deep learning models, neural network language model (NNLM), bidirectional long-short-term memory network (BiLSTM), and convolutional neural network (CNN), were established, and the accuracy rates of the three models were 87.78%, 90.37%, and 91.11%, respectively. The experimental results demonstrate the feasibility of serum Raman spectroscopy combined with deep learning algorithms to diagnose breast cancer, which can be used as an effective auxiliary diagnosis method for breast cancer.

Influence of coke heterogeneity and the interaction between different coke species on the emission of toxic HCN and NOx from FCC spent catalyst regeneration.

Concerning the emissions of hydrogen cyanide (HCN) and other N-bearing air pollutants from the fluid catalytic cracking (FCC) regeneration units, this paper has conducted a comprehensive testing and surface characterisation of four industrial spent catalysts, aged catalysts and hard coke sample in three different schemes, Ar-TPD, O2 -TPO and rapid heating to elaborate the transformation of N upon the influence of the heterogeneity of coke and N speciation. In the Ar-TPD scheme, the surface N is responsive for the emission of gaseous NH3 from pyrrolic N-5 and HCN from both pyridinic N-6 and quaternary N-Q. The removal of soft coke is beneficial in promoting the surface exposure of hard coke, thereby increasing the HCN emission dramatically. In the O2-TPO scheme, the oxygen accessibility is the principal factor governing the emission of HCN. The external soft coke is able to access the bulk O2 firstly, the combustion of which in turn provides heat back to promote the cracking of internal hard coke from the same and neighbouring particles to release more HCN. The induction effect of bulk O2 is also superior over the spent catalyst properties in formulating a nearly identical trend of HCN emission for all the four spent catalysts tested. Finally, for the use of rapid heating scheme that is typical in a commercial FCC regenerator, it is effective in accelerating the volatilisation of soft coke quickly, thereby promoting the oxygen accessibility to hard coke and the internal N-bearing precursors so as to mitigate the emission of HCN effectively. The use of a large superficial velocity of gas is further effective in sweeping the volatiles including HCN away from the catalyst, promoting their oxidation extent accordingly.

Bioinformatics Analysis Reveals Hub Genes That May Reduce Inflammation and Complications After Cardiopulmonary Bypass.

Cardiopulmonary bypass (CPB), though indispensable in many cardiac surgery procedures, has several undesirable consequences. The aim of this study was to identify potential genes that may reduce the inflammatory response and complications after CPB. The GSE132176 dataset was selected from the Gene Expression Omnibus (GEO) database and included 10 patients with tetralogy of Fallot and 10 patients with an atrial septal defect who underwent CPB surgery. TSV files were downloaded after GEO2R processing. Protein-protein interaction analysis of common differentially expressed genes (DEGs) was performed using the Search Tool for the Retrieval of Interacting Genes. Gene modules and hub genes were visualized in the protein-protein interaction network using Cytoscape. Enrichment analysis was performed for all important DEGs, modular genes, and hub genes. A total of 72 DEGs were screened, including two functional and one hub gene module. FOS modular genes were primarily enriched in NGF-stimulated transcription, spinal cord injury, and PID AP1 pathway. The ATF3 modular gene was mainly enriched in cytomegalovirus infection and transcriptional misregulation in cancer. Hub gene modules were primarily enriched in the PID AP1 pathway, positive regulation of pri-miRNA transcription by RNA polymerase II, and the PID ATF2 pathway. FOS, JUN, ATF3, and EGR1 were the four most important hub genes; the top three hub genes were involved in the formation of AP-1 and enriched in the AP-1 pathway. Finally, we measured the expression levels of these four genes in patients undergoing CPB via qRT-PCR, and the results were consistent with those obtained in bioinformatic analysis. FOS, JUN, ATF3, and EGR1 and the AP-1 pathway may play key roles in inflammation and complications caused by CPB.

Rapid identification of papillary thyroid carcinoma and papillary microcarcinoma based on serum Raman spectroscopy combined with machine learning models.

Thyroid carcinoma is with the highest diagnosis rate in the endocrine system, and its main histological subtype is papillary thyroid carcinoma (PTC) accounting for 80% of thyroid malignancies. In recent years, the incidence of thyroid cancer has increased exponentially, and its substantial increase was closely related to the overdiagnosis of papillary microcarcinoma (PMC). Therefore, early and accurate identification of PTC and PMC can prevent patients from over treatment. This study aimed to identify PTC and PMC using Raman spectroscopy. We collected serum Raman spectra from 16 patients with PTC and 31 patients with PMC. Firstly, the collected imbalance data were preprocessed using the synthetic minority over-sampling technique (SMOTE). Then, the equalized data were dimensionality reduced by principal component analysis (PCA). Finally, the processed data were fed into the single decision tree (DT) classifier, as well as the random forest (RF) built on the idea of Boosting ensemble and the Adaptive Boosting (Adaboost) model built on the idea of Bagging ensemble for classification. The classification accuracy of the three models in the testing set were 75.38%, 81.54%, and 84.61%, respectively. Compared with the DT classifier, the accuracy of the models introducing the idea of ensemble learning was enhanced by 6.16% and 9.23%, respectively. The best model was the Adaboost. This result demonstrates that serum Raman spectroscopy combined with an ensemble learning algorithm was feasible in rapidly identifying PTC and PMC. At the same time, the method has great potential for application in the field of clinical diagnosis.

Hierarchical Attentional Feature Fusion for Surgical Instrument Segmentation.

Instrument segmentation is a crucial and challenging task for robot-assisted surgery operations. Recent commonly-used models extract feature maps in multiple scales and combine them via simple but inferior feature fusion strategies. In this paper, we propose a hierarchical attentional feature fusion scheme, which is efficient and compatible with encoder-decoder architectures. Specifically, to better combine feature maps between adjacent scales, we introduce dense pixel-wise relative attentions learned from the segmentation model; to resolve specific failure modes in predicted masks, we integrate the above attentional feature fusion strategy based on position-channel-aware parallel attention into the decoder. Extensive experimental results evaluated on three datasets from MICCAI 2017 EndoVis Challenge demonstrate that our model outperforms other state-of-the-art counterparts by a large margin.

The Second Wave of COVID-19 in South and Southeast Asia and the Effects of Vaccination.

Background: By February 2021, the overall impact of coronavirus disease 2019 (COVID-19) in South and Southeast Asia was relatively mild. Surprisingly, in early April 2021, the second wave significantly impacted the population and garnered widespread international attention. Methods: This study focused on the nine countries with the highest cumulative deaths from the disease as of August 17, 2021. We look at COVID-19 transmission dynamics in South and Southeast Asia using the reported death data, which fits a mathematical model with a time-varying transmission rate. Results: We estimated the transmission rate, infection fatality rate (IFR), infection attack rate (IAR), and the effects of vaccination in the nine countries in South and Southeast Asia. Our study suggested that the IAR is still low in most countries, and increased vaccination is required to prevent future waves. Conclusion: Implementing non-pharmacological interventions (NPIs) could have helped South and Southeast Asia keep COVID-19 under control in 2020, as demonstrated in our estimated low-transmission rate. We believe that the emergence of the new Delta variant, social unrest, and migrant workers could have triggered the second wave of COVID-19.

NHBS-Net: A Feature Fusion Attention Network for Ultrasound Neonatal Hip Bone Segmentation.

Ultrasound is a widely used technology for diagnosing developmental dysplasia of the hip (DDH) because it does not use radiation. Due to its low cost and convenience, 2-D ultrasound is still the most common examination in DDH diagnosis. In clinical usage, the complexity of both ultrasound image standardization and measurement leads to a high error rate for sonographers. The automatic segmentation results of key structures in the hip joint can be used to develop a standard plane detection method that helps sonographers decrease the error rate. However, current automatic segmentation methods still face challenges in robustness and accuracy. Thus, we propose a neonatal hip bone segmentation network (NHBS-Net) for the first time for the segmentation of seven key structures. We design three improvements, an enhanced dual attention module, a two-class feature fusion module, and a coordinate convolution output head, to help segment different structures. Compared with current state-of-the-art networks, NHBS-Net gains outstanding performance accuracy and generalizability, as shown in the experiments. Additionally, image standardization is a common need in ultrasonography. The ability of segmentation-based standard plane detection is tested on a 50-image standard dataset. The experiments show that our method can help healthcare workers decrease their error rate from 6%-10% to 2%. In addition, the segmentation performance in another ultrasound dataset (fetal heart) demonstrates the ability of our network.

Quercetin attenuates reduced uterine perfusion pressure -induced hypertension in pregnant rats through regulation of endothelin-1 and endothelin-1 type A receptor.

BACKGROUND: Quercetin was reported to be crucial for a broad range of activities, including attenuating inflammation, platelet aggregation, capillary permeability, and lipid peroxidation. However, the effect of quercetin in hypertension during pregnancy, was not fully understood. METHODS: The model of hypertension in pregnancy was established in rats by reduced uterine perfusion pressure (RUPP). Quercetin was administrated by gavage. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured using the CODA 6 BP system. Plasma concentrations of Endothelin-1 (ET-1), soluble fms-like tyrosine kinase-1 (sFlt-1), and vascular endothelial growth factor (VEGF) were detected using enzyme-linked immunosorbent assay kits. The mRNA and protein levels of ET-1 and endothelin-1 type A receptor (ETAR) were determined by RT-PCR and Western blotting. The ETAR antagonist BQ-123 was performed by osmotic minipumps. RESULTS: In RUPP induced rats, quercetin treatment decreased SBP and DBP, fetal resorptions percentage, plasma ET-1 and sFlt-1 concentrations, ET-1 and ETAR levels, but increased fetal body weight and VEGF expression. BQ-123 administration attenuated SBP and DBP, suppressed fatal resorptions percentage, and increased fetal body weight of RUPP rats. CONCLUSION: Quercetin attenuates RUPP induced hypertension in pregnant rats through the regulation of ET-1 and ETAR.

MicroRNA-384 Inhibits the Growth and Invasion of Renal Cell Carcinoma Cells by Targeting Astrocyte Elevated Gene 1.

MicroRNAs (miRNAs) are emerging as pivotal regulators in the development and progression of various cancers, including renal cell carcinoma (RCC). MicroRNA-384 (miR-384) has been found to be an important cancer-related miRNA in several types of cancers. However, the role of miR-384 in RCC remains unclear. In this study, we aimed to investigate the potential function of miR-384 in regulating tumorigenesis in RCC. Here we found that miR-384 was significantly downregulated in RCC tissues and cell lines. Overexpression of miR-384 significantly inhibited the growth and invasion of RCC cells, whereas inhibition of miR-384 had the opposite effects. Bioinformatic analysis and luciferase reporter assay showed that miR-384 directly targeted the 3'-untranslated region of astrocyte elevated gene 1 (AEG-1). Further data showed that miR-384 could negatively regulate the expression of AEG-1 in RCC cells. Importantly, miR-384 expression was inversely correlated with AEG-1 expression in clinical RCC specimens. Moreover, miR-384 regulates the activation of Wnt signaling. Overexpression of AEG-1 significantly reversed the antitumor effects of miR-384. Overall, these findings suggest that miR-384 suppresses the growth and invasion of RCC cells via downregulation of AEG-1, providing a potential therapeutic target for the treatment of RCC.

MicroRNA­613 inhibits proliferation and invasion of renal cell carcinoma cells through targeting FZD7.

MicroRNAs (miRNAs) have emerged as critical regulators in cancer progression. miR­613 has been reported as a tumor suppressor gene in many types of human cancers. However, the function of miR­613 in renal cell carcinoma (RCC) remains unclear. In the present study, the authors aimed to detect the expression of miR­613 and its function in RCC cell lines. miR­613 was reported to be significantly downregulated RCC cell lines. Functional analyses demonstrated that overexpression of miR­613 significantly decreased RCC cell proliferation and invasion. Bioinformatics analysis showed that Frizzled7 (FZD7) was a predicted target of miR­613, which was verified by dual­luciferase reporter assay, reverse transcription quantitative­polymerase chain reaction and western blot analysis. Restoration of FZD7 significantly reversed the suppressive effects of miR­613 on RCC cell proliferation and invasion. Taken together, the results of the present study indicated that miR­613 functions as a tumor suppressor that inhibits RCC cell proliferation and invasion by targeting and inhibiting FZD7, providing novel insight into RCC pathogenesis and a potential therapeutic target for RCC.

TRIM16 suppresses the progression of prostate tumors by inhibiting the Snail signaling pathway.

Prostate carcinoma is a devastating disease which is characterized by insidious early symptoms, rapid progression and a poor prognosis. Tripartite motif-containing protein 16 (TRIM16) was identified as an estrogen- and antiestrogen-regulated gene in epithelial cells stably expressing estrogen receptors. The protein encoded by this gene contains two B-box domains and a coiled-coiled region that are characteristic of the B-box zinc finger protein family. Proteins belonging to this family have been reported to be involved in a variety of biological processes including cell growth, differentiation and pathogenesis. TRIM16 expression has been detected in most tissues. However, the funtions of this gene remain to be elucidated. In the present study, immunohistochemical staining revealed that the expression of TRIM16 was decreased in prostate adenocarcinoma compared with that in normal prostate tissues. The patients with high TRIM16-expressing tumors had a significantly greater survival than those with low TRIM16-expressing tumors. Western blot analysis showed that TRIM16 was downregulated in distant metastatic cancer tissues compared with that in non-distant metastatic cancer tissues. The overexpression of TRIM16 inhibited the migration and invasion of prostate cancer cells as well as inhibiting the epithelial-to-mesenchymal transition process, whereas TRIM16 depletion enhanced these processes. Moreover, TRIM16 inhibited the Snail signaling pathway. The silencing of Snail by small interfering RNA was performed in order to determine the role of Snail in the TRIM16-mediated tumor phenotype. Taken together, these findings suggest that TRIM16 may be an important molecular target which may aid in the design of novel therapeutic agents for prostate cancer.

MicroRNA-200a-3p suppresses tumor proliferation and induces apoptosis by targeting SPAG9 in renal cell carcinoma.

Sperm-associated antigen 9(SPAG9), as a well-recognized oncogene protein, has a critical effect on renal cell carcinoma (RCC) progression. Our study tried to explore the mediator of miR-200a-3p, a tumor suppressing miRNA on SPAG9 expression and renal cell proliferation and apoptosis. We found the expression of miR-200a-3p was significantly lower in RCC specimens. Based on in vitro assays, we found miR-200a-3p significantly inhibit cancer cell proliferation by inducing apoptosis. In addition, our study uncovered that miR-200a-3p directly regulates oncogenic SPAG9 in 786-O and ACHN cells. Silencing of SPAG9 resulted in significantly decreased in the growth and the cell cycle of the renal cancer cell lines. Understanding of oncogenic SPAG9 regulated by miR-200a-3p might be beneficial to reveal new therapeutic targets for RCC.

[Application of vestibular autorotation test in diagnosis of benign paroxysmal positional vertigo].

OBJECTIVE: The objective of this study was to evaluate the utility of vestibular autorotation test in the diagnosis of BPPV. METHOD: VAT and caloric test were performed on 41 patients with BPPV. VAT results were analyzed according to the affected semicircular canal. RESULT: Results of VAT were abnormal in 34 (82.93%) patients with BPPV. Fourteen cases were found with abnormal vertical phase, 1 case with abnormal vertical gain in a total of 21 vertical semicircular canal BPPV patients. Six cases with abnormal horizontal phase lead, 5 cases with abnormal horizontal gain, 2 cases with asymmetry were found in 12 patients with horizontal semicircular canal BPPV. Phase lead was abnormal in all frequencies in 4 patients, and in 2-3 Hz in 21 patients. 24 (58.54%) patients showed abnormal canal paresis (CP) and direction preference (DP) in caloric test. CONCLUSION: VAT can indicate information of vestibular function in both vertical and horizontal semicircular canal. Phase of VAT is constantly enhanced in BPPV, especially in 2-3 Hz. As the supplement of caloric test, VAT may prove helpful in assessment of semicircular canal function.

[Clinical features of multiple canal involvement in benign paroxysmal positional vertigo].

OBJECTIVE: To describe a series of patients with multiple canal involvement in benign paroxysmal positional vertigo (BPPV), with respect to diagnosis and management. METHODS: Ninety-five individuals with symptoms of BPPV and positional nystagmus were included in this study. The diagnosis was based on a history of brief episodes of vertigo and the presence of multiple positional nystagmus as confirmed by video-oculographic examination. Patients were treated by means of different particle repositioning manoeuvres according to the affected canal. RESULTS: Ninety-five patients showed multiple positional nystagmus during the examination corresponding to simultaneous multi-canal BPPV. Fourteen patients (14.7%) had bilateral canal BPPV. Six patients had bilateral posterior canal. Six patients had bilateral horizontal canal, and two patients had bilateral anterior canal. Fifty-three patients (55.8%) had torsional, up-beating nystagmus with down-beating nystagmus, which suggested possible affected both of posterior and anterior canals. Twenty patients (21.1%) had torsional up-beating nystagmus and horizontal direction nystagmus, which suggested possible affected both of posterior and horizontal canals. Five patients had down-beating nystagmus with horizontal nystagmus, which suggested affected both of anterior and horizontal canals. Three patients had torsional up-beating with down-beating and horizontal nystagmus, which suggested possible affected multiple canals. Treatment given to the patients varied according to the canal affected, started with the canal that elicited a strong positional nystagmus and vertigo, and 93.7% (89/95) of patients were symptom free or improved. CONCLUSIONS: It has been found that multi-canal BPPV is not a rate observation in clinic, and most of them affected posterior and anterior canals. Treatment of multi-canal BPPV can be effective using repositioning maneuver.

[A finite element investigation of bilateral atlantoaxial trans-articular screws and atlas laminar hooks instrumentation].

OBJECTIVES: To investigate the mechanical properties of bilateral atlantoaxial trans-articular screws and atlas laminar hooks instrumentation with finite element method. METHODS: There was a volunteer with age of 28 years old, body height 172 cm, body weight of 60 kg and without cervical deformity by X rays. The ligamentous, nonlinear, three-dimensional finite element models of normal upper cervical spine (C0-3) was developed and validated. The destabilized model with bilateral atlantoaxial trans-articular screws and atlas laminar hooks was evaluated for quasistatic loading. RESULTS: The finite element model of upper cervical spine consists of 229,047 nodes and 152,475 elements, and correlated well with experimental data for all load cases and could be used for experiment. The finite model with bilateral atlantoaxial trans-articular screws and atlas-laminar hooks predicted that the maximum Von Mises Stress was in the region in which screws penetrated the atlantoaxial articular facet. The novel instrumentation resulted in sufficient stability. CONCLUSION: The bilateral atlantoaxial trans-articular screws and atlas laminar hooks instrumentation is useful and effective for atlantoaxial arthrodesis.

[Diagnosis and therapy for benign paroxysmal positional vertigo of the anterior semicircular canal].

OBJECTIVE: To analyse the video-oculographic findings of positional tests and evaluate the efficacy of canalith repositioning procedure (CRP) in patients with paroxysmal positional vertigo ( BPPV) of the anterior semicircular canal (ASC). METHODS: A retrospective study of 31 patients with ASC BPPV. Then the CRP was performed. RESULTS: Twenty-two individuals (70.97%) presented a unilateral positional nystagmus during the Dix-Hallpike test, in 17 individuals had torsional nystagmus component, 5 individuals only had pure positional down beat nystagmus. Nine patients presented bilateral positional nystagmus, 7 individuals had torsional component positional nystagmus, in 2 patients the direction of the torsional component were the same during right and left Dix-Hallpike test, in 4 patients the torsional component were concurrent with positional down beat nystagmus but the direction could not be ascertained clinically, in 2 patients had pure positional down beat nystagmus. Nineteen patients (61.29%) had unilateral lesion, 11 patients had the left ASC BPPV, 8 patients had right ASC BPPV. Eleven patients had with both ASC and PSC BPPV in the ipsilateral. Twenty-one patients (67.74%) were cured, 29 patients (93.55%) were improved, 2 (6.45%) patients were inefficacy. CRP effectively resolved the nystagmus and vertigo in 14 patients (45.16%) when applied only once, The average number of CRP was 1.7 times, there were 5 patients recurrence during the follow-up. CONCLUSIONS: ASC BPPV was not a common condition. The torsional nystagmus component of ASC BPPV might be weak during the Dix-Hallpike test. The positional nystagmus of ASC BPPV was triggered bilaterally. Based on these findings, CRP could be one of the most effective treatment methods for ASC BPPV.

[Mice lacking of voltage-gated L-type calcium channel alpha1D subunit have impaired sinoatrial node function and caused deafness].

OBJECTIVE: L-type voltage-gated calcium channel subunit alpha1D-/- mice (homozygous mutant, knockout), alpha1D+/- (heterozygous) and alpha1D+/+ (wild-type) have played role in L-type voltage-gated calcium channel alpha1D subunit in auditory function of inner ear as well as sinoatrial node function of the mice. METHOD: Hearing threshold and endocochlear potential (EP) were measured in the alpha1D knockout mice, heterozygous mice and wild-type mice by auditory brainstem response(ABR), EP recordings and Electrocardiograph (ECG) respectively. To assessment of the vestibular function of the mice, the ability of Balancing was performed by a swim test and a horizontal cylinder test. RESULT: The auditory function of alD+/+ mice were normal, the mean value for ABR thresholds in response to click sound stimulus was (34.8 +/- 5.7) dB SPL,EP was (105.3 +/- 3.1) mV. The mean value for ABR thresholds in response to click sound stimulus was elevated in alpha1D+/- mice was (54.4 +/- 12.4) dB SPL, relative to that observed in alpha1D+/+ mice significantly increased (P < 0.05); EP of alpha1D+/- mice was about (75.8 +/- 9.9) mV. alpha1D-/- mice were completely deaf, the ABR wave form was not observed for even 100 dB SPL sound stimuli used and EP was still remain in (48.6 +/- 19.3) mV. alpha1D knockout mice were deaf and demonstrated no vestibular defect. alpha1D+/- and alpha1D-/- mice show significant sinus bradycardia with significant prolongation of the RR interval (146 +/- 1.4 and 244 +/- 2.9, respectively) comparing to the alpha1D+/+ wild-type mice (117 +/- 0.4) in the same littermates. In addition, the homozygous alpha1D-/- show a significant prolongation of the PR interval (53 +/- 0.5) compared to that of the a1D+/+ wild-type mice (38 +/- 0.3). CONCLUSION: L-type voltage-gated calcium channel alpha1D subunit plays a critical role in calcium homeostasis in the inner ear. Mice lacking of alpha1D calcium channel gene would lead to influence auditory function and sinoatrial node dysfunction subsequently.

Protein kinase A mediates voltage-dependent facilitation of Ca2+ current in presynaptic hair cells in Hermissenda crassicornis.

The simplest cellular model for classical conditioning in the nudibranch mollusk, Hermissenda crassicornis, involves the presynaptic hair cells and postsynaptic photoreceptors. Whereas the cellular mechanisms for postsynaptic photoreceptors have been studied extensively, the presynaptic mechanisms remain uncertain. Here, we determined the phenotype of the voltage-dependent Ca(2+) current in the presynaptic hair cells that may be directly involved in changes in synaptic efficacy during classical conditioning. The Ca(2+) current can be classified as a P-type current because its activation voltage under seawater recording conditions is approximately -30 mV, it showed slow inactivation, and it is reversibly blocked by omega-agatoxin-IVA. The steady-state activation and inactivation curves revealed a window current, and the single-channel conductance is approximately 20 pS. The P-type current was enhanced by cAMP analogs (approximately 1.3-fold), and by forskolin, an activator of adenylyl cyclase (approximately 1.25-fold). In addition, the P-type current showed voltage-dependent facilitation, which is mediated by protein kinase A (PKA). Specifically, the PKA inhibitor peptide [PKI(6-22)amide] blocked the enhancement of the Ca(2+) current produced by conditioning depolarization prepulses. Because neurotransmitter release is mediated by Ca(2+) influx via voltage-gated Ca(2+) channels, and because of the nonlinear relationship between the Ca(2+) influx and neurotransmitter release, we propose that voltage-dependent facilitation of the P-type current in hair cells would produce a robust change in synaptic efficacy.