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91.
应用食道心房调博缩测定健康小儿窦房结功能,以了解西宁地区正常数值与平原地区进行对比。选择27例健康小儿,将F6二级电极导管从鼻腔送入,定位地食道心电图最大正负双相P波处,采用苏州东方电子仪器厂生产的DF-3A型心脏电生理治疗仪进行检查,从而作出诊断。 相似文献
92.
We present a new mathematical model for vagal control of rabbit sinoatrial (SA) node electrical activity based on the DiFrancesco-Noble
equations. The original equations were found to be unstable, resulting in progressive cycle by cycle depletion or accumulation
of ions in intra- and extracellular compartments. This problem was overcome by modifying the maximum Na−K pump current and
the time constant for uptake of intracellular calcium. We also included a formulation for the acetylcholine (ACh)-activated
potassium current which was consistent with experimental data. This formulation was based on kinetics first proposed by Osterrieder
and later modified by Yanagihara. The resulting model exhibits cycle-cycle ionic stability, and includes an ACh-activated
potassium current which accurately reproduces experimentally observed effects of vagal stimulation on both the membrane potential
and its timederivative. Simulations were performed for both brief-burst and prolonged vagal stimulation using simplified square
wave profiles for the concentration of ACh in the synaptic cleft space. This protocol permits the isolation of cardiac period
dynamics caused by changes in membrane potential and intra- and extracellular ionic concentrations from those caused by other
mechanisms including the dynamics of ACh release, diffusion, hydrolysis and washout. Simulation results for the effects of
brief-burst single cycle stimulation on the cardiac period agree closely with experimental data reported in the literature,
accurately reproducing changes in membrane potential and the phasic dependency of the response to the position of vagal stimulus
bursts within the cycle. Simulation of the effects of prolonged vagal stimulation accurately reproduced the steady-state characteristics
of heart period response, but did not yield the complex multimodal dynamics of the recovery phase, or the pronounced post
vagal tachycardia observed experimentally at the termination of the stimulus. Our results show that the major chronotropic
effects of vagal stimulation on the SA cell membrane can be explained in terms of the ACh-activated potassium current. The
effects of this membrane current however are generally fast acting and cannot contribute to any long lasting dynamics of the
cardiac period response. The modified DiFrancesco-Noble model presented in this article provides a valuable theoretical tool
for further analysis of the dynamics of vagal control of the cardiac pacemaker. 相似文献
93.
目的:检测lnc-CCDC33-1:1在甲状腺乳头状癌(PTC)中的表达,并分析其临床意义。方法:选取2021年11月至2022年3月杭州市萧山区第一人民医院收治的120例PTC患者,收集120例PTC组织及30例癌旁正常甲状腺组织。采用qRT-PCR检测lnc-CCDC33-1:1在PTC组织及癌旁组织中的表达。分析本地队列和TCGA队列中lnc-CCDC33-1:1表达水平与PTC患者临床病理因素的相关性。采用受试者工作特征(ROC)曲线评价lnc-CCDC33-1:1对PTC的诊断价值。结果:与癌旁正常甲状腺组织比,lnc-CCDC33-1:1在PTC组织中表达明显升高(P <0.001)。ROC曲线显示曲线下面积为0.803(95%CI =0.736~0.869,P <0.001)。本地队列显示lnc-CCDC33-1:1 表达与PTC肿瘤大小(P =0.048)、腺外侵犯(P =0.019)、T分期(P =0.011)和淋巴结转移(P =0.009)相关,TCGA组数据显示lnc-CCDC33-1:1表达水平与PTC腺外侵犯(P =0.036)和淋巴结转移(P <0.001)相关。结论:lnc-CCDC33-1:1在PTC中表达异常升高,与PTC高危特征相关,可能是潜在的诊断标志物和治疗靶点。 相似文献
94.
95.
PAOLO ALBONI NELLY PAPARELLA RICCARDO CAPPATO PAOLO PEDRONI GIAN CARLO CANDINI GIAN ENRICO ANTONIOLI 《Pacing and clinical electrophysiology : PACE》1989,12(2):294-300
The purpose of this study was to find out whether transesophageal pacing could be utilized for assessment of sinus node function in patients with sick sinus syndrome (SSS). In 17 patients with SSS (study group) we compared the results of sinus node tests obtained both in the basal state and after pharmacological autonomic blockade by endocavitary stimulation and, 24 hours later, by transesophageal pacing. In another group of 17 patients with SSS (control group), we compared the results obtained by two endocavitary studies. In "study group", sinus cycle length (SCL) and corrected sinus node recovery time (CSRT) did not show significant differences between the two studies both in the basal state and after autonomic blockade, whereas sinoatrial conduction time (SACT) was more prolonged during esophageal pacing (P less than 0.01). In "control group", sinus node measures did not show significant differences between the two studies. In the "study group," the following coefficients of correlation were obtained in the basal state; SCL, r = 0.65, CSRT, r = 0.57, SACT, r = 0.52 and after autonomic blockade: SCL, r = 0.95, CSRT, r = 0.62 and SACT, r = 0.53. In the basal state, the correlation for SCL and CSRT between the two studies was lower in the "study group" than in the "control group" (P less than 0.05), whereas after autonomic blockade the correlation for sinus node measures did not show significant differences between the two groups of patients. These data suggest that transesophageal study influences the autonomic tone regulating the sinus node; however, it is not responsible for important variations in sinus node measures.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
96.
Grabau DA Rank F Friis E 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》2005,113(1):7-12
The study presents the results from intraoperative frozen section assessment of axillary sentinel lymph nodes (SLNs) in breast cancer. Routine histological frozen sections from one level were used, two sections stained with haematoxylin and eosin. Immunohistochemistry for cytokeratins was applied to the permanent SLN paraffin sections only. Axillary dissection was performed on all SLN-positive cases regardless of the size of the metastatic deposits. With a detection rate of 83%, 272 patients entered the study over a period of 46 months. A total of 61 cases were SLN positive by frozen section analysis. The paraffin sections gave an additional 23 SLN-positive cases. The false-negative rate for frozen sections was then 27% (23/84). Micrometastases were found in 28 of 84 cases, and macrometastases in 56. The false-negative rate of frozen sections for micrometastases was 71% (20/28), and for macrometastases 5% (3/56). A total of 73% (61/84) of the patients underwent axillary surgery as a one-step procedure. 相似文献
97.
Jiqing Guo Tamotsu Mitsuiye A. Noma 《Pflügers Archiv : European journal of physiology》1997,433(4):390-396
Single myocytes were dissociated from the sino-atrial (SA) node of guinea-pig hearts. Only a quite small fraction of the
cell population showed spontaneous action potentials and these cells were characterized by the presence of the hyperpolarization-activated
cation current I
f , the delayed rectifier K+ current I
K and the L-type Ca2+ current I
Ca,L as well as by the absence of both the transient outward current I
to and the inward rectifier K+ current I
K,1. After blocking I
f and I
K, depolarizing pulses from –80 mV revealed a large nicardipine-sensitive late current (NSLC). The NSLC was scarcely affected
by decreasing extracellular [Ca2+] ([Ca2+]o) from 1.8 to 0.1 mM, while it was decreased significantly by depleting [Na+]o, differently from I
Ca,L. NSLC was blocked by nicardipine and was increased by Bay K 8644. NSLC was increased by isoprenaline and the additional application
of acetylcholine reversed the increase of this current. We conclude that NSLC is largely composed of I
st described in the rabbit SA node pacemaker cells, and that I
st is unique for the pacemaker cells in mammalian SA node cells. Most of the quiescent cells showed neither I
f nor I
st.
Received: 22 July 1996 / Received after revision: 30 September 1996 / Accepted: 9 October 1996 相似文献
98.
Sato A Taniguchi I Fujiwara D Ichikawa H Suzuki M Nawata S Murakami G 《Anatomical science international / Japanese Association of Anatomists》2003,78(4):211-222
Gaps and fragmentation of the superficial lymph node cortex are considered to provide intranodal shunt flow between the afferent
and efferent vessels. Using serial sections of 205 nodes obtained from 27 donated cadavers more than 70 years of age, we examined
the histological architecture of the abdominal and pelvic nodes in elderly Japanese. Secondary follicles were rare in the
specimens. Cortex gaps were, to a greater or lesser degree, found in all nodes. We classified these nodes into three types
according to how often the gap occurred. Type 1 nodes, with a relatively complete shield for the afferent lymph, were most
frequently found in gastric nodes, whereas type 3 nodes, with numerous gaps, were often observed in the colic, para-aortic
and pelvic nodes. The type 3 nodes showed a specific architecture characterized by a fragmented superficial cortex, three-dimensionally
assembled cords and a common sinus between them. Primary follicles were located in the assembled cord structures as well as
at the superficial cortex. Irrespective of the type, B and T lymphocyte areas were intermingled in the cortex-like areas.
The present results reveal region-specific histological heterogeneity in aged human visceral nodes. Due to increased surface
areas, the type 3 architecture seemed to accelerate systemic immunity rather than act as a local barrier in the para-aortic
and pelvic nodes, which are located centrally along the lymphatic drainage routes. However, thick trabeculae often seemed
to develop in the type 3 sinus to decrease nodal function with aging. 相似文献
99.
Deborah U Frank Sarah A Elliott Eon Joo Park Jennetta Hammond Yukio Saijoh Anne M Moon 《Developmental dynamics》2007,236(4):1085-1092
We targeted the reverse tetracycline controlled transactivator (rtTA) to the Foxa2 locus (Foxa2(ITA)) to generate a system for regulating Cre-recombinase activity within Foxa2 expression domains, including the endoderm, notochord, and floor plate of early mouse embryos. The use of an internal ribosomal entry site to obtain rtTA expression preserves Foxa2 function of the targeted allele. Cre activity with this system reflects the level of endogenous Foxa2 activity and is also tightly controlled by doxycycline. The location of Cre activity within the broader Foxa2 expression domain can be restricted by altering the timing of doxycycline administration. Isolated floor plate expression can be obtained in this manner. This system will provide a useful tool for manipulating gene expression in endoderm, notochord, and floor plate, all of which are tissues with important structural and patterning functions during embryogenesis. 相似文献
100.
Class switch recombination (CSR), somatic hypermutation, and gene conversion are immunoglobulin diversification mechanisms that are strictly dependent on the activity of the activation-induced cytidine deaminase (AID). The precise role and substrate(s) of AID in these processes remain to be well defined. The closest homologue of AID is APOBEC-1, a bona fide mRNA-editing enzyme, which shares with AID the ability to deaminate cytidines within single-stranded DNA in vitro and in prokaryotic cells. To determine whether APOBEC-1 can therefore substitute for AID in activated B cells, we expressed human AID, a catalytic mutant thereof, and rat APOBEC-1 in AID-deficient murine B cells. Whereas AID rescued CSR, neither the inactive mutant nor APOBEC-1 could complement AID deficiency. This indicates that cytidine deaminase activity is necessary but not sufficient to initiate CSR, and suggests that AID is specifically targeted to its cognate substrate, the immunoglobulin genes or a distinct mRNA, by an as-yet-unknown mechanism. 相似文献