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Objectives@#. Reactive oxygen species in the stria vascularis (SV) of the cochlea may be involved in the pathogenesis of sensorineural hearing loss. However, the effects of oxidative stress on SV endothelial cells (SV-ECs) remain largely unknown, and no feasible in vitro cell culture model exists for the functional study of SV-ECs. @*Methods@#. We isolated primary SV-ECs from the SV of neonatal mice. The apoptosis-reducing effects of fibronectin in SV-ECs cultured with serum-free medium were determined using β-galactosidase staining and flow cytometry. SV-ECs incubated in serum-free medium were treated with various H2O2 concentrations to evaluate the effects of H2O2 on their viability. The secretome of SV-ECs treated with or without H2O2 (100 μM or 500 μM) was analyzed using high-resolution mass spectrometry. The function of the SV-EC secretome was evaluated by a macrophage assay. @*Results@#. We successfully isolated and characterized the SV-ECs. Treatment with H2O2 at concentrations up to 500 μM for 2 hours and further incubation with serum-free medium in plates precoated with fibronectin showed no significant effect on apoptosis. Compared to the control SV-ECs, the amount of differential proteins in the secretome of SV-ECs stimulated with 500 μM H2O2 was much higher than in those treated with 100 μM H2O2. Kyoto Encyclopedia of Genes and Genomes and Gene Ontology analyses suggested that the proteins differentially expressed in SV-ECs treated with 500 μM H2O2 were involved in the regulation of multiple signaling pathways and cellular processes. The secretome of H2O2-stimulated SV-ECs exhibited significant pro-inflammatory effects on macrophages. @*Conclusion@#. We successfully established an in vitro serum-free culture method, identified the differential proteins released by oxidative stress-induced ECs and their functions, and revealed the pro-inflammatory effects of the secretome of H2O2-stimulated SV-ECs. Therefore, SV-ECs might elicit immunoregulatory effects on bystander cells in the microenvironment of oxidative stress-induced cochlea, especially cochlear macrophages.
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Objective To compare the effects of carbohydrate-electrolyte beverage on post-exercise rehydration of healthy young men in different seasons,and to explore the influence of seasonal adaptability on fluid and electrolyte balance.Methods Fifteen healthy men,aged(24.4±0.5)years,completed 2 trails in a random crossover design both in summer and winter.During recovery,they consumed a drink volume equivalent to 100% of their sweat loss with plain boiled water(the water group)or carbohydrate-electrolyte beverage(the beverage group).Recovery was monitored for further 180 minutes by the collection of blood and urine samples.Results The dehydration time in summer was significantly shorter by about 20 minutes than that in winter(
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Adulto , Humanos , Masculino , Bebidas , Estudios Cruzados , Carbohidratos de la Dieta , Electrólitos , Fluidoterapia , Estaciones del AñoRESUMEN
Objective:To observe the effect of dictyophora polysaccharide (DIP) on PINK1/Parkin pathway mediated mitophagy induced by sodium arsenite (NaAsO 2) in human hepatocytes (L-02 cells). Methods:The L-02 cells in logarithmic growth phase and in good condition were divided into control group, NaAsO 2 group (10 μmol/L), DIP group (80 μg/ml), DIP + NaAsO 2 group (80 μg/ml DIP + 10 μmol/L NaAsO 2) , N-acetylcysteine (NAC) group (5 mmol/L), and NAC + NaAsO 2 group (5 mmol/L NAC + 10 μmol/L NaAsO 2). Western blotting was used to detect the expression levels of mitophagy related proteins p62, microtubule-associated protein 1 light chain 3 (LC3)Ⅱ/LC3Ⅰ, PINK1, and Parkin. The mitochondrial stucture and autophagosomes were observed by transmission electron microscope, the fluorescent probe method was used to detect the expression level of intracellular reactive oxygen species (ROS). Results:Compared with the control group, the protein expressions of p62, LC3 Ⅱ/LC3 Ⅰ, PINK1, and Parkin in NaAsO 2 group were higher ( P < 0.05); compared with the NaAsO 2 group, the protein expressions of p62, LC3 Ⅱ/LC3 Ⅰ, PINK1 and Parkin were lower in DIP, DIP + NaAsO 2, NAC, and NAC + NaAsO 2 groups ( P <0.05). According to the transmission electron microscope, compared with the control group, the mitochondria of L-02 cells in NaAsO 2 group were significantly damaged and the number of autophagosomes increased. Compared with NaAsO 2 group, the degree of mitochondrial swelling, vacuolar degeneration and the number of autophagosomes decreased in DIP + NaAsO 2 group. Compared with the control group (33 110.00 ± 2 191.28), the intracellular ROS level in NaAsO 2 group was higher (48 000.00 ± 2 395.31, P < 0.05); the level of intracellular ROS in DIP + NaAsO 2 group (38 670.00 ± 2 620.56) was significantly lower than that in NaAsO 2 group( P < 0.05), and there was no significant change compared with the control group ( P > 0.05). Conclusions:NaAsO 2 can induce PINK1/Parkin mediated mitophagy in L-02 cells. DIP can alleviate NaAsO 2 induced mitophagy. DIP may affect PINK1/Parkin mediated mitophagy induced by NaAsO 2 through the regulation of ROS.
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BACKGROUND@#Gastric cancer (GC) is one of the most globally prevalent cancers in the world. The pathogenesis of GC has not been fully elucidated, and there still lacks effective targeted therapeutics. The influence of altered kinesin superfamily protein 22 (KIF22) expression in GC progression is still unclearly. The aim of this study was to investigate the KIF22 effects on GC and related mechanisms.@*METHODS@#Gastric carcinoma tissues and matching non-cancerous tissues were collected from patients with GC who have accepted a radical gastrectomy in Lanzhou University Second Hospital from May 2013 to December 2014. The expression of KIF22 was examined in GC of 67 patients and 20 para-carcinoma tissues by immunochemical staining. The relationship between the expression of KIF22 and clinicopathologic characteristics was next investigated in the remaining 52 patients except for 15 patients who did not complete follow-up for 5 years. Cell viability was performed via 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) test and colony formation assay in the MGC-803 and BGC-823 GC cells. Cell scratch and trans-well invasion assay was performed to assess migration ability in the MGC-803 and BGC-823 GC cells. Gene set enrichment analysis (GSEA) pathway enrichment analysis was performed to explore the potential functions. Cell cycle was detected by flow cytometry. In addition, the two GC cell lines were used to elucidate the underlying mechanism of KIF22 in GC in vitro via assessing the effects on mitogen-activated protein kinase and extracellular regulated protein kinases (MAPK/ERK) signal transduction pathway-related expressions by Western blotting assays. The differences were compared by t tests, one-way analysis of variance, and Chi-squared tests.@*RESULTS@#The study showed that KIF22 was up-regulated in GC, and KIF22 high expression was significantly related to differentiation degree (χ = 12.842, P = 0.002) and poorly overall survivals. GSEA pathway enrichment analysis showed that KIF22 was correlated with the cell cycle. Silence of KIF22 decreased the ability of the proliferation and migration in gastric cells, induced G1/S phase cell cycle arrest via regulating the MAPK-ERK pathways.@*CONCLUSIONS@#KIF22 protein level was negatively correlated with prognosis. KIF22 knockdown might inhibit proliferation and metastasis of GC cells via the MAPK-ERK signaling pathway.
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[Objective] To evaluate the efficacy of sound therapy and provide a kind of treatment for tinnitus patients with normal audiogram.[Methods] From the database of the Audiometric Center of the First Affiliated Hospital,Sun Yat-sen University,we identified 46 outpatients with normal hearing thresholds in the conventional pure-tone audiometry suffering subjective tinnitus over 3 months.The clinical information were collected with respect of age,gender,tinnitus severity,pitch,laterality and duration,comorbid symptoms.All the patients received the tinnitus test,including loudness and frequency of the tinnitus and residual inhibition,Tinnitus Handicap Inventory (THI) and Visual Analogue Scale (VAS) scores pre-and post-complex sound therapy.The complex sound were remixed with natural sounds and music materials,while the masking frequency of natural sounds is consistent with the tinnitus frequency of patients and the main frequency of music materials covers the tinnitus frequency.[Results] 32 of the 46 patients showed residual inhibition (RI) positive.The average THI score before treatment was 33.38±16.23 and the VAS score was 4.38±1.62.The THI score decreased to 21.75±11.67 and the VAS score was 2.97±1.06 after sound therapy.The rest 14 patients were residual inhibition (RI) negative.The THI score were 29.86±20.15 and 23.43±16.29 pre-and post-complex sound therapy,while the VAS score were 3.93±1.69 and 3.36±1.2.The THI and VAS scores were significantly decreased after the treatment in both RI positive and negative patients.The RI positive group showed better results than RI negative group.[Conclusions] Both RI positive and negative tinnitus with normal audiometry shown adaptation with complex sound therapy,RI positive patients acquired more benefits from tailor-made complex sound therapy.
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Objective:To investigate the effect of dexmedetomidine on stress response and cellular immune function in patients undergoing radical resection of colon cancer during perioperative period.Methods: 96 cases of colon cancer undergoing radical resection were randomly divided into dexmedetomidine group(group D)and control group(group C).The group D was intubated with in-travenous infusion of dexmedetomidine 0.6 μg/kg,followed by intravenous infusion of 0.3 μg/(kg·h) at the end of the surgery,and the group C was given 0.9% saline at equal volume and rate.The venous blood of patients was collected before anesthesia induction,10 min(T0),immediate postoperative(T1),postoperative 24 h(T2)and postoperative 72 h(T3).Flow cytometry were used to detect T lym-phocyte subsets(CD3+,CD4+,CD8+,CD4+/CD8+)and the percentage of NK cells,and determination of norepinephrine(NE), epinephrine(E),cortisol(Cor),IL-6,IL-10 and TNF-α levels.Records of patients with T0,immediate intubation(Ta),T1,immediate extubation(Tb)of SBP,DBP,MAP,and postoperative adverse reactions were recorded.Results:The SBP,DBP and MAP of group C at Ta,T1,Tbwere significantly higher than that of T0and group D(P<0.05).Compared to those at T0,the levels of CD3+,CD4+,CD8+and CD4+/CD8 at T1and T2were significantly lower in both groups(P<0.05),and the levels of group C at T1,T2,T3were significantly lower than those in group D(P<0.05).The NK cells of group C at T1,T2were significantly lower than that of T0and group D(P<0.05).Compared to those at T0,the levels of IL-6,IL-10 and TNF-α at T1and T2were significantly higher in both groups(P<0.05), and the levels in group C were significantly higher than those in group D(P<0.05).The IL-6 and IL-10 of group C at T3were significantly higher than that of T0and group D(P<0.05).Compared to those at T0,the levels of NE,E and Cor at T1and T2were sig-nificantly higher in both groups(P<0.05),and the levels in group C were significantly higher than those in group D(P<0.05).The NE,E and Cor of group C at T3were significantly higher than that of T0and group D(P<0.05).The proportion of adverse reactions in group D was significantly lower than that in group C(χ2= 4.800,P= 0.028).Conclusion: Dexmedetomidine can inhibit the perioperative stress response and reduce the impact on immune function in patients undergoing radical resection of colon cancer.
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Objective To investigate and analyze the clinical efficacy of cefoperazone and Shubatan in the treatment of severe infection in emergency department. Methods 100 cases of severe infection were randomly divided into control group and experimental group, with 50 patients in each group. The control group received routine treatment, and the experimental group was treated with cefoperazone and Shubatan on this basis. Pay close attention to the related vital signs change of the experimental group and the control group, the relevant clinical indicators of the two groups of patients were compared and analyzed. Results After the corresponding treatment, the bacteria removal rate of the experimental group was 90.00%, significantly higher thant 60.00 % of the control group (P<0.05). The effective rate of the experimental group was 90.00%, which was significantly higher than that of the control group (74.00%), which was statistically significant (P<0.05). There were no obvious adverse reactions in the two groups. After treatment, the total score of quality of life in the experimental group was (75.2±11.2) points, and the total score of QOL in the control group was (64.2±9.3) points, which was statistically significant (P<0.05). Conclusion The clinical efficacy of cefoperazone and Shubatan in the treatment of emergency severe infection is satisfactory. It can significantly improve the clinical symptoms and improve the quality of life in patients with severe acute respiratory infection.
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Objective To investigate and analyze the clinical efficacy of cefoperazone and Shubatan in the treatment of severe infection in emergency department. Methods 100 cases of severe infection were randomly divided into control group and experimental group, with 50 patients in each group. The control group received routine treatment, and the experimental group was treated with cefoperazone and Shubatan on this basis. Pay close attention to the related vital signs change of the experimental group and the control group, the relevant clinical indicators of the two groups of patients were compared and analyzed. Results After the corresponding treatment, the bacteria removal rate of the experimental group was 90.00%, significantly higher thant 60.00 % of the control group (P<0.05). The effective rate of the experimental group was 90.00%, which was significantly higher than that of the control group (74.00%), which was statistically significant (P<0.05). There were no obvious adverse reactions in the two groups. After treatment, the total score of quality of life in the experimental group was (75.2±11.2) points, and the total score of QOL in the control group was (64.2±9.3) points, which was statistically significant (P<0.05). Conclusion The clinical efficacy of cefoperazone and Shubatan in the treatment of emergency severe infection is satisfactory. It can significantly improve the clinical symptoms and improve the quality of life in patients with severe acute respiratory infection.
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<p><b>OBJECTIVE</b>To explore the effect of the interaction between PLIN gene polymorphisms and open lifestyle intervention on weight-loss in Chinese Han adults.</p><p><b>METHODS</b>Totally 109 overweight or obese subjects were assigned by random number table to the intervention group (n=56) or control group (n=53),and subjects in the intervention group received 22-week open lifestyle intervention. Anthropometric and metabolic indicators were measured for all subjects before and after intervention,and the PLIN1,PLIN4,and PLIN6 genotypes were amplified by polymerase chain reaction and sequenced through the first-generation sequencing technologies.</p><p><b>RESULTS</b>Among all these subjects,the rare allele C was dominant at PLIN1 (0.619),the common allele G was dominant at PLIN4 (0.606),and the common allele A was dominant at PLIN6 (0.564),in which PLIN1 and PLIN4 as well as PLIN4 and PLIN6 were in strong linkage disequilibrium (D'>0.9). After intervention,the body mass index,waist circumference,and body fat percent of female subjects were significantly decreased in intervention group and were lower than in control group;in male subjects,however,only the waist circumference showed significant difference with the control group (P<0.05). Subjects carrying rare allele homozygote of PLIN6 got less weight/fat loss than those carrying common alleles in intervention group,while subjects carrying rare allele of PLIN1 had more weight/fat increase than those with common allele homozygote in control group (P<0.05). Females in intervention group carrying any one of rare allele homozygotes of PLIN1,PLIN4 and PLIN6 got less weight/fat loss than those with common alleles,and female subjects carrying the rare allele homozygote haplotype of PLIN1/PLIN4 or PLIN4/PLIN6 got less weight/fat loss than those with other haplotypes (P<0.05).</p><p><b>CONCLUSION</b>The interaction between open lifestyle intervention and PLIN gene polymorphisms can directly influence weight-loss in Chinese Han overweight and obese adults.</p>
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Adulto , Femenino , Humanos , Masculino , Tejido Adiposo , Alelos , Índice de Masa Corporal , Proteínas Portadoras , Genotipo , Estilo de Vida , Desequilibrio de Ligamiento , Obesidad , Fosfoproteínas , Polimorfismo Genético , Circunferencia de la Cintura , Pérdida de PesoRESUMEN
The applicator therapy is a unique method to treat infant diarrhea in traditional Chinese medicines and widely applied in clinical practice. Currently, many researchers have proved the rationality of the therapy based on the traditional Chinese medicine mechanism and on the data from clinical practice, but its action mechanism is uncertain at present. In this study, with the assistance of pediatric practitioners, the automated ribosomal intergenic-spacer analysis (ARISA) was adopted to study the effect of the adjuvant therapy with Dingguier umbilical paste on intestinal flora of diarrhea infants, in which Dingguier umbilical paste served as the adjuvant therapy in oral traditional Chinese medicines and fecal samples of infants with different diarrhea symptoms were collected and used as the study materials. The results showed that the adjuvant therapy had a significant effect on the shift of intestinal flora, which was associated with the decrease in the similarity difference to the normal control group and the increase in the number of operational taxonomic units (OTUs) shared with the normal control group. Additionally, adjuvant therapy with Dingguier umbilical paste also showed long action duration and increased OTUs number. These results indicated that Dingguier umbilical paste has the effect in restoring the micro-ecosystem of unbalanced intestinal bacteria. Intestinal flora may be one of major targets for the applicator therapy for the infant diarrhea, but not for the single oral traditional Chinese medicine for infant diarrhea.
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Femenino , Humanos , Lactante , Masculino , Adyuvantes Farmacéuticos , Usos Terapéuticos , Diarrea , Quimioterapia , Microbiología , Heces , Microbiología , Intestinos , Microbiología , Medicina Tradicional China , Métodos , Pomadas , Resultado del Tratamiento , OmbligoRESUMEN
Objective To analyze the clinical,radiological and pathological features of primary leiomyosarcoma of bone and to im-prove the diagnostic level.Methods Totally 6 cases of PLB proved by pathology were collected in our study.The clinical,radiologi-cal and pathological findings were retrospectively analyzed,and combined with the relevant literature to have a comprehensive analy-sis.Results The lesions of 6 patients were solitary,located in femoral (1 case),distal femur (1 case),proximal tibia (2 cases),is-chium (1 case)and humerus (1 case).There was no periosteal reaction in all 6 cases but they all had soft tissue mass,sometimes there may have some mineralization within the tumor.Ill-defined osteolytic bone destruction was detected in 5 patients,while expan-sion of cystic bone destruction was found in the other 1 patients.3 cases had hardened edge,2 cases with adjacent bone cortical thickening.The MR imaging in 5 patients showed iso-intensity signal on T1 WI,a slightly inhomogeneously higher signal on T2 WI and a significant heterogeneously enhancement after injected of Gd-DTPA.Another 1 patient showed a double ring sign,the central area onT1 WI and T2 WI expressed heterogeneous slightly higher signal,the peripheral annular zone was iso-intensity on T1 WI and slightly higher on T2 WI,after injected contrast medium,it was inhomogeneous enhancement.In immunohistochemically,all tumors reacted positively with SMA,3 patients with Desmin and Vimentin positive,2 patients with Ki-67 positive,and there had some scat-tered cells with CD68 positive,but the S-100 were all negative.Conclusion The clinical,radiological and conventional histological manifestations of PLB are not specific.Immunohistochemical and/or ultrastructural analysis who displayed smooth muscle differenti-ation can confirm the diagnosis.
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Objective To explore the strategies and effectiveness of perioperative fluid administration during pediatric kidney transplantation.Methods In our study,we evaluated the heart function and compliance of pediatric patients preoperatively,and then formulated perioperative fluid management strategy according to children’s circulation feature.The electrolytic balance was kept and complications were prevented.Results Twenty-nine out of all 48 children experienced electrolyte disturbance to different extents on day 1 postoperatively,which improved on day 2 after prompt management.There were five cases of oliguria,three cases of delayed graft function(DGF),one case of heart failure and multiple organ failure respectively.Conclusion Such nursing strategies like formulation of reasonable fluid infusion plan according to the physiological features of pediatric recipients,keeping the electrolytic balance and careful management of fluid at polyuria,oliguria and anuria,care critical for the children to live through the perioperative periods.
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Objective To investigate the effect of nicotinamide mononucleotide (NMN) on insulin secretion and gene expressions of pancreatic and duodenal homeobox 1 ( PDX-1 ) and forkhead box-containing protein O-1 ( FoxO1 ),which were important transcription factors for insulin secretion.Methods Insulin secretion level in RIN-m5f cells was detected by rat insulin ELISA detection kit.The mRNA expression levels of PDX-1 and FoxO1 in RIN-m5f cells were analyzed by real-time PCR.The protein expression of PDX-1 was measured by Western blot.Results Insulin secretion levels in RIN-m5f cells treated with repaglinide ( 10 nmol/L) plus NMN ( 100 μnol/L) was significantly higher than those in the blank control,the DMSO control group,and the NMN (50μmol/L) treated group (P ＜0.05 ).The mRNA expression levels of PDX-1 in RIN-m5f cells treated with NMN ( 10,50 and 100 μmol/L) for 36 h were significantly higher than those in the control group (P ＜0.05,P ＜ 0.01,and P ＜ 0.001,respectively).There was marked differences in the mRNA expression levels of PDX-1 among different concentrations of NMN (P ＜0.001 ),but no significant differences in the mRNA expression level of FoxO1 ( P ＞ 0.05).No significant difference was found in the protein expression levels of PDX-1 in RIN-m5f cells treated by NMN (50,100,and 200 μmol/L) for 36 or 48 h compared with the control group (P ＞ 0.05).Conclusion NMN can stimulate insulin secretion and upregulate the mRNA expression of PDX-1 in RIN-m5f cells.
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<p><b>OBJECTIVE</b>To detect the expression of DJ-1 in laryngeal squamous cell carcinoma (LSCC) and to study the relationship between DJ-1 expression and clinical indexes of LSCC.</p><p><b>METHODS</b>The expressions of DJ-1 protein in 71 LSCC samples and 9 cases control samples from laryngeal mucosa tissues of non-LSCC patients were detected using streptavidin peroxidase immunohistochemistry staining and the relationships between DJ-1 protein expression and clinicopathologic characteristics were analyzed.</p><p><b>RESULTS</b>(1) The positive expression rate of DJ-1 protein in LSCC was 85.9%(61/71), which was significantly higher than the rate (55.5%, 5/9) in control laryngeal mucosa tissues (P < 0.05). (2) DJ-1 expression was related to tumor recurrence (P < 0.05), but not to sex, age, primary cancer position, T stage, clinical stage, lymph node metastasis and tumor differentiation. Tumor recurrence rate (53.3%) in the patients with higher expression of DJ-1 protein was higher than the rate (26.8%) in the patients with lower expression of DJ-1 protein (χ(2) = 5.164, P < 0.05). (3) With Kaplan-Meier curves and Cox regression analysis, the cumulative 5-year survival rates were correlated with DJ-1 expression levels in laryngeal cancer tissues or cervical lymph node metastasis (all P < 0.05), but not to sex, age, primary cancer position, T stage, clinical stage and tumor differentiation.</p><p><b>CONCLUSIONS</b>The expression of DJ-1 protein in LSCC is higher than that in control laryngeal mucous tissues. Overexpression of DJ-1 is associated with poor overall survival in LSCC patients.</p>
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Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Carcinoma de Células Escamosas , Metabolismo , Patología , Estudios de Casos y Controles , Péptidos y Proteínas de Señalización Intracelular , Metabolismo , Neoplasias Laríngeas , Metabolismo , Patología , Metástasis Linfática , Recurrencia Local de Neoplasia , Estadificación de Neoplasias , Proteínas Oncogénicas , Metabolismo , Proteína Desglicasa DJ-1RESUMEN
<p><b>BACKGROUND</b>Few studies have explored the inward sodium current (INa) kinetics of transitional cardiomyocytes. This study aimed to explore the kinetics of transitional cardiomyocytes types alpha and beta.</p><p><b>METHODS</b>The whole-cell patch clamp technique was used to study the rapid INa of isolated transitional cardiomyocytes in the Koch triangle of rabbit hearts.</p><p><b>RESULTS</b>Maximal amplitude and density of INa in type alpha and type beta was (-1627 +/- 288) pA (alpha), (-35.17 +/- 6.56) pA/pF (beta) and (-3845 +/- 467) pA (alpha), (-65.64 +/- 10.23) pA/pF (beta) (P < 0.05). Steady state activation curves of INa, fitted to a Boltzmann distribution for both types, were sigmoid in shape. Half activation voltage and slope factors did not significantly differ between types at (-43.46 +/- 0.85) mV (alpha), (-41.39 +/- 0.47) mV (beta) or (9.04 +/- 0.66) mV (alpha), (11.08 +/- 0.89) mV (beta). Steady state inactivation curves of INa, fitted to a Boltzmann distribution in both types were inverse "S" shape. Half inactivation voltage and slope factors were (-109.9 +/- 0.62) mV (alpha), (-107.5 +/- 0.49) mV (beta) and (11.78 +/- 0.36) mV (alpha), (11.57 +/- 0.27) mV(beta), (P > 0.05), but time constants of inactivation were significantly different at (1.10 +/- 0.19) mV (alpha) and (2.37 +/- 0.33) ms (beta), (P < 0.05). Time constants of recovery from inactivation of INa for both types were (122.16 +/- 27.43) mV (alpha) and (103.84 +/- 28.97) ms (beta) (P < 0.05).</p><p><b>CONCLUSIONS</b>Transitional cardiomyocytes in rabbit hearts show a heterogeneous, voltage gated and time dependent fast inward sodium current. Types alpha and beta show the features of INa similar to those in slow- and fast-response myocytes, with probably better automaticity and conductivity, respectively.</p>
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Animales , Femenino , Masculino , Conejos , Activación del Canal Iónico , Cinética , Potenciales de la Membrana , Miocitos Cardíacos , Metabolismo , Canales de Sodio , FisiologíaRESUMEN
<p><b>OBJECTIVE</b>To quantitatively detect the expression of connexins (Cx) mRNA in the posterior nodal extension (PNE) of adult rat heart and understand the relationship between Cx expression and atrial ventricular nodal reentrant tachycardia (AVNRT).</p><p><b>METHODS</b>PNE was separated from adult rat heart by means of laser microdissection (LCM), and the cells were also isolated from the atrioventricular node (AVN), sinoatrial node (SAN), Purkinje fiber (PF), right atrium (RA) and right ventricle (RV), to serve as the controls. The Cx mRNA level was detected in these cells with quantitative real-time PCR (QRT-PCR).</p><p><b>RESULTS</b>The cells were successfully isolated from the PNE and other regions of adult rat heart, where heterogeneous expression of the 3 Cx isoforms (Cx43, Cx45, and Cx40) were observed. Cx45 mRNA showed higher expression in the PNE than in the working myocardium, whereas Cx43 mRNA level was about 25 times higher (P<0.05) in the working myocardium and 18 times higher (P<0.05) in the PF than in the PNE. In the PF, Cx40 mRNA level was proximately 6.8 times (P<0.01) as much as that in the PNE. Cx expression in the PNE was, however, similar to that in the SAN and AVN.</p><p><b>CONCLUSION</b>Cx mRNAs exhibit heterogeneous expression in the PNE to allow the formation of the slow pathway. In addition, Cx expression in the PNE is very different from that in the adjacent myocardium, resulting in conduction discontinuity at the cellular junction, where, on certain occasion, unidirectional block may occur to cause AVNRT.</p>
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Animales , Femenino , Masculino , Ratas , Nodo Atrioventricular , Biología Celular , Metabolismo , Conexina 43 , Genética , Conexinas , Genética , Miocardio , Biología Celular , Metabolismo , Ramos Subendocárdicos , Biología Celular , Metabolismo , ARN Mensajero , Genética , Metabolismo , Ratas Sprague-Dawley , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Nodo Sinoatrial , Biología Celular , MetabolismoRESUMEN
<p><b>BACKGROUND</b>The morphological and electrophysiological characteristics of cardiac cells in Koch triangle are still disputed. We studied the appearance and electrical properties of these diverse myocytes to elucidate their complex electrophysiological phenomena.</p><p><b>METHODS</b>Experiments were conducted using cooled charge coupling device (CCD) system and whole cell, patch clamp technique to determine the morphology, action potential and sodium current density of single viable myocytes enzymatically isolated from the Koch triangle of rabbit hearts.</p><p><b>RESULTS</b>Morphologically, cardiac cells in shape of spider, tiny spindle, slender spindle, rod and strip were observed in percentage of 3.0 +/- 0.3, 35.0 +/- 5.0, 15.0 +/- 2.0, 40.0 +/- 5.0 and 6.0 +/- 0.7 respectively. The cellular dimensions and capacitance gradually increased in the above order (all P < 0.05). Electrophysiologically, action potential configurations recorded from them were similar respectively to nodal (N), atrial nodal (AN), nodal Hisian (NH), atrial (A) and Hisian like potentials obtained from the intact atrioventricular nodal preparations. Diastolic depolarization appeared in all myocytes except for rod cells. Sodium current density increased in the order of tiny spindle, strip, rod, slender spindle cell (all P < 0.05), but could not be detected in spider-shaped cells. Linear regression analysis revealed that membrane capacitance was correlated negatively to the rate of diastolic depolarization r = -0.70, P < 0.001, but positively to maximum depolarization potential, amplitude of action potential, upstroke velocity and maximum peak value of sodium current density r = 0.84, 0.80, 0.87 and 0.75, respectively; all P < 0.001.</p><p><b>CONCLUSIONS</b>The results demonstrated that spider-shaped, spindle, rod and strip cells in Koch triangle might correspond to pacemaking, transitional, atrial and Purkinje like cells, respectively. Furthermore, tiny spindle and slender spindle cells were referred to transitional cell alpha (TCalpha) and beta (TCbeta) accordingly considering their distinctive electrical properties. Different myocytes with diverse electrical properties constituted the infrastructure of sophisticated electrophysiological phenomena in Koch triangle. In view of the prominent percentage and electrical properties, tiny spindle and slender spindle cells were presumed to play important roles.</p>