Clinico-pathological and gene features of 15 nemaline myopathy patients from a single Chinese neuromuscular center.

BACKGROUND: Nemaline myopathy, the most common of the congenital myopathies, is caused by various genetic mutations. In this study, we attempted to investigate the clinical features, muscle pathology and genetic features of 15 patients with nemaline myopathy. RESULTS: Among the 15 patients, there were 9 (60.00%) males and 6 (40.00%) females, and 9 (60.00%) of them came from three families respectively. The age of seeing a doctor ranged from 9 to 52 years old, the age of onset was from 5 to 23 years old, and the duration of disease ranged from 3 to 35 years. Ten out of the 15 patients had high arched palate and elongated face. Only one patient had mild respiratory muscle involvement and none had dysphagia. Muscle biopsies were performed in 9 out of the 15 patients. Pathologically, muscle fibers of different sizes, atrophic muscle fibers and compensatory hypertrophic fibers could be found, and occasionally degenerated and necrotic muscle fibers were observed. Different degrees of nemaline bodies aggregation could be seen in all 9 patients. The distribution of type I and type II muscle fibers were significantly abnormal in patients with nemaline myopathy caused by NEB gene, however, it was basically normal in patients with nemaline myopathy caused by TPM3 gene and ACTA1 gene. Electron microscopic analysis of 6 patients showed that nemaline bodies aggregated between myofibrils were found in 5(83.33%) cases, and most of them were located near the Z band, but no intranuclear rods were found. The gene analysis of 15 NM patients showed that three NM-related genes were harbored, including 11 (73.33%) patients with NEB, 3 (20.00%) patients with TPM3, and 1 (6.67%) patient with ACTA1, respectively. A total of 12 mutation sites were identified and included 10 (83.33%) mutations in exon and 2(16.67%) mutations in intron. CONCLUSIONS: The clinical phenotype of nemaline myopathy is highly heterogeneous. Muscle pathology shows that nemaline bodies aggregation is an important feature for the diagnosis of NM. NEB is the most frequent causative gene in this cohort. The splicing mutation, c.21522 + 3A > G may be the hotspot mutation of the NEB gene in Chinese NM patients.

[Retracted] MicroRNA-199b targets the regulation of ZEB1 expression to inhibit cell proliferation, migration and invasion in non­small cell lung cancer.

Following the publication of this paper, it was drawn to the Editors' attention by a concerned reader that cell migration assay data shown in Figs. 2D and 4D were strikingly similar to data that had appeared in different form in other articles by different authors (in addition to the apparent duplication of some of these data within this paper itself). 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 Molecular Medicine Reports, the Editor has decided that this paper should be retracted from the Journal. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor apologizes to the readership for any inconvenience caused. [Molecular Medicine Reports 16: 5007­5014, 2017; DOI: 10.3892/mmr.2017.7195].

Long-term development of dynamic changes in neurovascular coupling after acute temporal lobe epilepsy.

Epilepsy is an abnormal brain state that may be induced by synchronous neuronal activation and also abnormalities in energy metabolism or the oxygen supply vascular system. Neurovascular coupling (NVC), the relationship between neuron, capillary, and penetrating artery, remains unexplored on a fine-scale with respect to the pathology process after acute temporal lobe epilepsy (TLE). Here we use two-photon microscopy (TPM) to provide high temporal-spatial resolution imaging to identify changes in NVC during spontaneous and electro-stimulated (ES) states in awake mice. Implantation of a long-term craniotomy window allowed TPM recording of the pathological development after the acute Kainic Acid temporal lobe epilepsy model. Our results provide direct evidence that the capillary and penetrating artery are not correlated to rhythmic neuronal activity during acute epilepsy. During the CSD period, NVC shows a strong correlation. We demonstrate that NVC exhibits nonlinear dynamics after status epilepticus. Furthermore, the vascular correlation to neuronal signals in spontaneous and ES states shows dynamic changes which correlate to the evolution after acute TLE. Understanding NVC in all TLE stages, from the acute through the TLE pathological development, may provide new therapeutic pathways.

Carboplatin-induced renal salt-wasting syndrome in pediatric patients with intracranial germ cell tumors and concomitant diabetes insipidus.

We report a case series of 14 children with intracranial germ cell tumor and concomitant central diabetes insipidus, who developed hyponatremia secondary to renal salt-wasting syndrome (RSWS) following the administration of carboplatin. Clinicians prescribing platinum-based chemotherapy for this group of patients should be alert to the risk of RSWS. Regular monitoring should be performed as hyponatremia can be asymptomatic until it is severe.

[Effects of long-term nitrogen addition on the nitrogen pools in a meadow steppe ecosystem]. / é•¿æœŸæ°®æ·»åŠ å¯¹è‰ç”¸è‰åŽŸç”Ÿæ€ç³»ç»Ÿæ°®åº“çš„å½±å“.

Increasing atmospheric nitrogen (N) deposition greatly affects species diversity, productivity, and stability of ecosystems. It is thus of the great importance to understand how grassland N pools respond to the increased atmospheric N deposition. This study was conducted in a meadow steppe in Erguna, Inner Mongolia, China. There were six levels of N addition (i.e., 0, 2, 5, 10, 20 and 50 g·m-2·a-1) and two levels of mowing (i.e., mowing and unmown). Samples of aboveground tissues of dominant plant, root, aboveground litter, and soil to the depth of 100 cm were collected in the seventh year after treatments. The N content was measured and the N pool was calculated. The results showed that N addition significantly increased the N content of aboveground plant tissues and litter, as well as N pools of Leymus chinensis, plant community, litter and ecosystem. Mowing significantly increased the N content of L. chinensis leaf and litter, but reduced N pools of L. chinensis, plant community and litter, and did not affect their responses to N addition. There was a significant interactive effect between mowing and N addition on plant community N pool. High levels of N addition in the unmown treatment led to more N stored in the litter pool, with the saturation threshold for the plant community N pool occurred at 10 g·m-2·a-1. Under mowing treatment, the plant community N pool increased with the increasing N addition, and more N stored in plant community N pool after mowing. Mowing could alleviate the negative impacts of increasing N deposition on biodiversity and ecosystem stability, and extended postponing the occurrence of ecosystem N saturation induced by increasing N deposition.

Efficacy and safety of endostatin in combination with chemotherapy in small cell lung cancer: a phase 2 single-arm multicenter open-label trial.

BACKGROUND: Small-cell lung cancer (SCLC) is a type of lung cancer with high invasiveness and poor prognosis. Although SCLC is effective for initial treatment, the vast majority of patients will relapse, the efficacy of posterior line therapy is limited, and there is a lack of effective treatment. At the same time, in the past 30 years, there has been little progress in first-line treatment. With the progress of antiangiogenic therapy, whether it can be used in the treatment of SCLC is worth exploring. Therefore, a single-arm multicenter clinical study was conducted on the efficacy, optimization, and safety of endostatin combined chemotherapy in SCLC. METHODS: This study is a prospective non-blind single-arm multicenter study. From January 2016 to July 2019, a total of 22 patients with histologically diagnosed SCLC were enrolled in three centers. The treatment regimen was as follows: continuous intravenous pump infusion of endostatin (90 mg) for 72 hours, 3 days before chemotherapy, and continuous pump infusion of endostatin (120 mg) for 96 hours the next day following the infusion of chemotherapeutic drugs; the chemotherapy regimen was administered with standard platinum combined with etoposide once every 21 days. After six cycles, endostatin maintenance therapy was used until the disease progressed or intolerable adverse reactions occurred. The therapeutic effect was evaluated by imaging and oncology markers every two cycles, and the adverse reactions, tumor progression time, and patient survival time were recorded. RESULTS: Among the 21 patients analyzed, the median progression-free survival (PFS) was 8.0 months, the median overall survival (OS) was 13.6 months, the objective effective rate (ORR) was 61.9%, and the disease control rate (DCR) was 95.2%. All patients tolerated the treatment. The main adverse reactions were myelosuppression, albuminuria, nausea, and vomiting. The incidence of grade 3 or 4 adverse reactions was 7.2%, which could be relieved by symptomatic support treatment. There were no treatment-related deaths. CONCLUSIONS: Endostatin combined with platinum-etoposide is safe and effective in the treatment of SCLC.

Challenges and opportunities for managing pediatric central nervous system tumors in China.

Central nervous system (CNS) tumors represent the most deadly cancer in pediatric age group. In China, thousands of children are diagnosed with CNS tumors every year. Despite the improving socioeconomic status and availability of medical expertise within the country, unique challenges remain for the delivery of pediatric neuro-oncology service. In this review, we discuss the existing hurdles for improving the outcome of children with CNS tumors in China. Need for precise disease burden estimation, lack of intra- and inter-hospital collaborative networks, high probability of treatment abandonment, along with financial toxicities from treatment represent the key challenges that Chinese healthcare providers encounter. The tremendous opportunities for advancing the status of pediatric neuro-oncology care in and beyond the country are explored.

[Effects of nitrogen and plant growth promoter addition on the growth and competitiveness of Leymus chinensis]. / æ°®ç´ å’Œæ¤ç‰©ç”Ÿé•¿ä¿ƒè¿›å‰‚å¯¹ç¾Šè‰ç”Ÿé•¿åŠç«žäº‰åŠ›çš„å½±å“.

With a greenhouse pot experiment, we investigated the effects of nitrogen (N) and plant growth promoter (brassinolide, BR) addition on the growth and competitive ability of three common plant species of typical steppe in Inner Mongolia, including Leymus chinensis, Astragalus adsurgens and Stipa krylovii. We added N at rates of 0, 0.1, 0.2, 0.4, 0.8 mg·g-1 soil and BR at rates of 0 and 0.005 mg·g-1 soil during plant growth in monoculture or with L. chinensis being planted in mixing with other two species, respectively. There were significant effects on biomass of L. chinensis and A. adsurgens, but not on that of S. krylovii with increase of N and BR addition. The effects of N addition on the growth of L. chinensis varied with accompanying plant species. Nitrogen addition increased aboveground biomass production of L. chinensis when growing in monoculture and mixed with A. adsurgens, but decreased its belowground biomass when growing mixed with S. krylovii. With increasing soil N availability, plant biomass allocation of L. chinensis showed significant decrease in root-shoot ratio when it was in monoculture or mixed with S. krylovii, but similar changes were not found when it was planted in mixing with A. adsurgens. The significant effects of BR addition on plant growth appeared occasionally. BR addition significantly reduced belowground biomass of A. adsurgens in its monoculture and significantly increased aboveground biomass of L. chinensis when it was planted in mixing with A. adsurgens. The results indicated that the appropria-tely combined addition of N and BR could effectively enhance biomass production of specific species combinations in grasslands, which has application prospects in the restoration of degraded grassland.

Stress-induced epinephrine enhances lactate dehydrogenase A and promotes breast cancer stem-like cells.

Chronic stress triggers activation of the sympathetic nervous system and drives malignancy. Using an immunodeficient murine system, we showed that chronic stress-induced epinephrine promoted breast cancer stem-like properties via lactate dehydrogenase A-dependent (LDHA-dependent) metabolic rewiring. Chronic stress-induced epinephrine activated LDHA to generate lactate, and the adjusted pH directed USP28-mediated deubiquitination and stabilization of MYC. The SLUG promoter was then activated by MYC, which promoted development of breast cancer stem-like traits. Using a drug screen that targeted LDHA, we found that a chronic stress-induced cancer stem-like phenotype could be reversed by vitamin C. These findings demonstrated the critical importance of psychological factors in promoting stem-like properties in breast cancer cells. Thus, the LDHA-lowering agent vitamin C can be a potential approach for combating stress-associated breast cancer.

The Prognostic Value of Nodal Staging in Triple-Negative Breast Cancer - A Cohort from China.

To evaluate the clinical outcomes and relationship between tumor size, lymph node status, and prognosis in a large cohort of patients with triple-negative breast cancer (TNBC).849 Patients were categorized by tumor size and nodal status. The Kaplan-Meier method and Cox proportional hazards models were used to determine the association of nodal status and tumor size with survival outcomes. A Sidak adjustment was used for pairwise group comparisons. We conducted six pairwise comparisons between different node status. In univariate and multivariate analyses, it was indicated that N0 patients had similar prognoses as N1 patients (P = 0.072), and the OS of both of these groups was significantly better than that of N2/N3 patients (N0 vs N2, P < 0.001; N0 vs N3, P < 0.001; N1 vs N2, P = 0.014; N1 vs N3, P = 0.005). In summary, we report that in Chinese patients with triple-negative breast cancer, a greater difference in survival was observed between N1 and N2 than between N0 and N1, warranting the possible need of more intensive chemotherapy for N2-3 patients. We also found that tumor size made an impact on survival when lymph nodes were extensively involved, a finding that needs longer follow-up and further validation.

Measurement-device-independent quantum communication without encryption.

Security in communication is vital in modern life. At present, security is realized by an encryption process in cryptography. It is unbelievable if a secure communication is achievable without encryption. In quantum cryptography, there is a unique form of quantum communication, quantum secure direct communication, where secret information is transmitted directly over a quantum channel. Quantum secure direct communication is drastically distinct from our conventional concept of secure communication, because it does not require key distribution, key storage and ciphertext transmission, and eliminates the encryption procedure completely. Hence it avoids in principle all the security loopholes associated with key and ciphertext in traditional secure communications. For practical implementation, defects always exist in real devices and it may downgrade the security. Among the various device imperfections, those with the measurement devices are the most prominent and serious ones. Here we report a measurement-device-independent quantum secure direct communication protocol using Einstein-Podolsky-Rosen pairs. This protocol eradicates the security vulnerabilities associated with the measurement device, and greatly enhances the practical security of quantum secure direct communication. In addition to the security advantage, this protocol has an extended communication distance, and a high communication capacity.

MicroRNA-199b targets the regulation of ZEB1 expression to inhibit cell proliferation, migration and invasion in non­small cell lung cancer.

Lung cancer is one of the leading causes of cancer-associated mortality worldwide. Previous evidence suggested that microRNAs (miRs) exhibit important regulatory roles in tumorigenesis and tumor development, including in non­small cell lung cancer (NSCLC). The present study investigated the expression of miR­199b in NSCLC tissues and cell lines, in addition to the biological roles of miR­199b in the carcinogenesis and progression of NSCLC. The results of the present study demonstrated that miR­199b expression was decreased in NSCLC tissues and cell lines compared with matched adjacent healthy tissues and a healthy human bronchial epithelial cell line, respectively. An MTT assay demonstrated that the viability of NSCLC cells was decreased by miR­199b. The migratory and invasive abilities of NSCLC cells were suppressed by miR­199b overexpression. In addition, zinc finger E­box­binding homeobox 1 (ZEB1) was identified to be a novel direct downstream and functional target for miR­199b in NSCLC, using bioinformatics analysis, luciferase reporter assay, the reverse transcription­quantitative polymerase chain reaction and western blotting. ZEB1 underexpression mimicked the roles of miR­199b overexpression in NSCLC cells. In conclusion, the present study demonstrated that miR­199b was downregulated in NSCLC and acted as a tumor suppressor by targeting ZEB1.

Changes in the Intestinal Microbiota of Gibel Carp (Carassius gibelio) Associated with Cyprinid herpesvirus 2 (CyHV-2) Infection.

Gut microbiota are integral to the host, and have received increased attention in recent years. However, information regarding the intestinal microbiota of many aquaculture animals is insufficient; elucidating the dynamics of the intestinal microbiota can be beneficial for nutrition, immunity, and disease control. In this study, we used 16S rRNA sequencing to observe changes in the intestinal microbiota of gibel carp (Carassius auratus gibelio) associated with cyprinid herpesvirus 2 (CyHV-2) infection. Our results indicate that the diversity of the intestinal microbiota was strongly reduced, and the composition was dramatically altered following CyHV-2 infection. The most dominant species in healthy fish were Cetobacterium, Rhodobacter, and Crenothrix; meanwhile, Cetobacterium, Plesiomonas, Bacteroides, and Flavobacterium were the most abundant species in sick fish. Plesiomonas was highly abundant in infected samples, and could be used as a microbial biomarker for CyHV-2 infection. Chemical properties of the aquaculture water were significantly correlated with the microbial community structure; however, it is difficult to determine whether these changes are a cause or consequence of infection. However, it may be possible to use probiotics or prebiotics to restore the richness of the host intestinal microbiota in infected animals to maintain host health.

Association of statin use and stress-induced hyperglycemia in patients with acute ST-elevation myocardial infarction.

BACKGROUND: Only a few information is available on the risk of stress hyperglycemia following acute myocardial infarction after statin use. We investigate the association of stress-induced hyperglycemia following statin use in patients with acute myocardial infarction. METHODS: An observational analysis of 476 consecutive patients who suffered acute myocardial infarction was carried out. All selected patients were divided into diabetes mellitus and non-diabetes based on the presence or absence of diabetes. The cardiac incidence of in-hospital and stress-induced hyperglycemia was recorded. RESULTS: Among patients with stress hyperglycemia in non-diabetes mellitus subgroups, the average fasting plasma glucose values in statin users were higher than in non-statin users (P < 0.05). But in diabetes mellitus subgroups, the average fasting plasma glucose did not have a significant difference between statin users and non-statin users (P > 0.05). In non-diabetes mellitus patients, the incidence of stress hyperglycemia with statin therapy was significantly higher than with non-statin therapy (P = 0.003). But in diabetes mellitus patients group, there is no significant difference in incidence of stress hyperglycemia between patients with statin therapy and patients without statin therapy (P = 0.902).The incidence of heart failure and in-hospital mortality of acute myocardial infarction in patients with stress-induced hyperglycemia was significantly higher than in non-hyperglycemia patients (P < 0.05). CONCLUSION: Statins are related to higher stress hyperglycemia and cardiac incidences after acute myocardial infarction.

Novel laparoscopic narrow band imaging for real-time detection of bile leak during hepatectomy: proof of the concept in a porcine model.

INTRODUCTION: Bile leakage is a serious complication occurring in up to 10 % of hepatic resections. Intraoperative detection of bile leakage is challenging, and concomitant blood oozing can mask the presence of bile. Intraductal dye injection [methylene blue or indocyanine green (ICG)] is a validated technique to detect bile leakage. However, this method is time-consuming, particularly in the laparoscopic setting. A novel narrow band imaging (NBI) modality (SPECTRA-A; Karl Storz, Tuttlingen, Germany) allows easy discrimination of the presence of bile, which appears in clear orange, by image processing. The aim of this experimental study was to evaluate SPECTRA-A ability to detect bile leakage. METHODS: Twelve laparoscopic partial hepatectomies were performed in seven pigs. The common bile duct was clipped distally and dissected, and a catheter was inserted and secured with a suture or a clip. Liver dissection was achieved with an ultrasonic cutting device. Dissection surfaces were checked by frequently switching on the SPECTRA filter to identify the presence of bile leakage. Intraductal ICG injection through the catheter was performed to confirm SPECTRA findings. RESULTS: Three active bile leakages were obtained out of 12 hepatectomies and successfully detected intraoperatively by the SPECTRA. There was complete concordance between NBI and ICG fluorescence detection. No active leaks were found in the remaining cases with both techniques. The leaking area identified was sutured, and SPECTRA was used to assess the success of the repair. CONCLUSIONS: The SPECTRA laparoscopic image processing system allows for rapid detection of bile leaks following hepatectomy without any contrast injection.

The configuration exchanging theory for transport properties and glass formation temperature of ionic liquids.

Understanding molecular motion in terms of molecular structure is an important issue for microscopic understanding of the nature of transport properties and glass transition, and for design of structured materials to meet specific demands in various applications. Herein, a novel molecular mechanism is proposed to connect macroscopic motion in ionic liquids with molecular structure via conformational conversions of the constituent ions or of the cation-anion pairs. New equations for description of relaxation time, diffusion coefficient, molar conductivity, and viscosity of ionic liquids are established. The equation parameters, which were determined from the temperature dependent heat capacities, self-diffusion coefficients, molar conductivities, and viscosities of typical ionic liquids, were used to produce predictions for the corresponding properties of other ionic liquids and for the glass transition temperatures of representative ionic liquids. All predictions are in nice agreements with the experimental results.

[Effect of specific sequence oligodeoxynucleotide MT01 on the proliferation, apoptosis, and cell cycle of osteoblasts invaded by Porphyromonas gingivalis].

OBJECTIVE: This aimed to investigate the effect of specific sequence oligodeoxynucleotide MT01 on the biological properties of osteoblasts invaded by Porphyromonas gingivalis (P. gingivalis ) by evaluating proliferation, cell cycle, and apoptosis. METHODS: MG63 osteoblasts were recovered and incubated with MT01, CpG ODN, metronidazole (MNZ), and gentamicin (GEN) for 3 h. P. gingivalis (the multiplicity of infection was 100:1) was added subsequently and cocultured for another 24 and 48 h. Cells with PBS comprised the blank group, whereas cells with P. gingivalis comprised the negative controls. Six experimental groups were established: PBS group, P. gingivalis group, MT01+P. gingivalis group, CpG ODN+ P. gingivalis group, MNZ+P. gingivalis group, and GEN+P. gingivalis group. The proliferative ability was measured by methyl thiazolyl tetrazolium assay, and the percentages of apoptosis and cell cycle were examined by flow cytometry. RESULTS: Compared with the blank group, proliferation increased significantly in the MT01+P. gingivalis group (P < 0.05). The ratio of cells was lower at the G1 phase and higher at the S phase in the MT01+P. gingivalis group compared with the results in the P. gingivalis group (P < 0.05). Early cell apoptosis in the MT01+P. gingivalis group was significantly lower than that in the P. gingivalis group (P < 0.05). CONCLUSION: MT01 can promote the proliferation, reduce the ratio of the G1phase, increase the ratio of the S phase, and inhibit the early apoptosis of osteoblasts invaded by P. gingivalis.

The programmed death-1 gene polymorphism (PD-1.5 C/T) is associated with non-small cell lung cancer risk in a Chinese Han population.

It has been proposed that genetic factors contribute to the susceptibility of non-small cell lung cancer (NSCLC). The programmed death-1 (PD1) is an immunoinhibitory receptor belonging to the CD28/B7 family. The aim of this study is to investigate the relationship between PD-1.5 C/T and NSCLC risk in a Chinese population. A population-based case-control study was conducted in 324 NSCLC patients and 330 cancer-free controls. The genotype of the PD-1.5 C/T was determined by using a polymerase chain reaction assay. Statistically significant difference was observed when the patients and controls were compared according to CC+CT versus TT (OR=2.34, 95% CI 1.35-4.06, P=0.003). The C allele was significantly associated with NSCLC risk (OR=1.421, 95% CI 1.10-1.82, P=0.006). Compared to TNM stage I+II, PD-1.5 C/T significantly increased advanced NSCLC risk (OR=2.66, 95% CI 1.07-6.63, P=0.03). The results from this study suggested that PD-1.5 C/T was potentially related to NSCLC susceptibility in Chinese Han population.

Cardiac adaptive mechanisms of Tibetan antelope (Pantholops hodgsonii) at high altitudes.

OBJECTIVE: To identify cardiac mechanisms that contribute to adaptation to high altitudes in Tibetan antelope (Pantholops hodgsonii). ANIMALS: 9 male Tibetan antelope and 10 male Tibetan sheep (Ovis aries). PROCEDURES: Tibetan antelope and Tibetan sheep inhabiting a region with an altitude of 4,300 m were captured, and several cardiac variables were measured. Expression of genes for atrial natriuretic peptide, brain natriuretic peptide, and calcium-calmodulin-dependent protein kinase II δ was measured via real-time PCR assay. RESULTS: Ratios of heart weight to body weight for Tibetan antelope were significantly greater than those of Tibetan sheep, but ratios of right-left ventricular weights were similar. Mean ± SD baseline heart rate (26.33 ± 6.15 beats/min) and systolic arterial blood pressure (97.75 ± 9.56 mm Hg) of antelope were significantly lower than those of sheep (34.20 ± 6.57 beats/min and 130.06 ± 17.79 mm Hg, respectively). The maximum rate of rise in ventricular pressure in antelope was similar to that in Tibetan sheep, but after exposure to air providing a fraction of inspired oxygen of 14.6% or 12.5% (ie, hypoxic conditions), the maximum rate of rise in ventricular pressure of the antelope increased significantly to 145.1% or 148.1%, respectively, whereas that of the sheep decreased to 68.4% or 70.5%, respectively. Gene expression of calcium-calmodulin-dependent protein kinase II δ and atrial natriuretic peptide, but not brain natriuretic peptide, in the left ventricle of the heart was significantly higher in antelope than in sheep. CONCLUSIONS AND CLINICAL RELEVANCE: Hearts of the Tibetan antelope in this study were well adapted to high-altitude hypoxia as shown by higher heart weight ratios, cardiac contractility in hypoxic conditions, and expression of key genes regulating cardiac contractility and cardiac hypertrophy, compared with values for Tibetan sheep.

Electrophysiologic characteristics of the Crista terminalis and implications on atrial tachycardia in rabbits.

The objective of this study was to evaluate the electrophysiologic characteristics of Crista terminalis (CT) and their implication in the pathogenesis of atrial tachycardia in rabbits. For this purpose, 27 New Zealand rabbits were used. Using standard glass microelectrode technique, cellular action potentials (APs) of CT and pectinate muscle (PM) were recorded in normal Tyrode's perfusion and Tyrode's perfusion with 4 µM isoproterenol. Longitudinal conduction velocity (V(L)) and transverse conduction velocity (V(T)) of CT were measured. As our data show, CT tissue had a trend of spontaneous phase IV depolarization. Conduction anisotropy (V(L)/V(T)) of CT was 4.53 ± 0.91. The duration of the AP of CT was longer than that of PM cells. APD(20) and APD(90) for CT were 28.1 ± 3.5 and 145.3 ± 7.1 ms; and for PM cells were 21.8 ± 4.1 and 125.3 ± 6.3 ms, respectively (all P values < 0.01). The early and delayed action depolarizations were recorded after isoproterenol perfusion. A fast paroxysmal irregular rhythm was recorded which could be arrested by 0.1 mmol/l Isoptin. It was, therefore, concluded that the latent autorhythmicity, trigger activity, and conduction properties of CT might provide the electrophysiologic basis for the occurrence and sustenance of atrial arrhythmia.