Effect of dexmedetomidine on rabbit heart rate: in vitro and in vivo experiments / 中华麻醉学杂志

Objective To evaluate the effect of dexmedetomidine on heart rate (HR) of rabbits through in vitro and in vivo experiments, and investigate the mechanism by which dexmedetomidine lowered HR.Methods In vitro experiment Healthy adult rabbits of both sexes, weighing 2.0-2.5 kg, aged 8-10 weeks, were studied.The 24 isolated hearts passively perfused in a Langendorff apparatus were randomly divided into 3 groups (n =8 each) using a random number table: control group (group C) , and dexmedetomidine 3 and 30 ng/ml groups (D1 and D2 groups).The isolated hearts were continuously perfused with K-H solution for 45 min in group C.After 15 min of equilibration, the isolated hearts were perfused for 30 min with K-H solution containing dexmedetomidine 3 and 30 ng/ml in D1 and D2 groups, respectively.At 15 min of equilibration, and at 15 and 30 min of perfusion with K-H solution containing dexmedetomidine, HR and left ventricular systolic pressure (LVSP) were recorded.In vivo experiment Twenty-five healthy adult rabbits of both sexes, weighing 2.0-2.5 kg, aged 8-10 weeks, were randomly divided into 5 groups (n=5 each) using a random number table: dexmedetomidine 3, 6, 9, 12, and 15 μg/kg groups (D3, D6, D9, D12, D15groups), to receive the corresponding doses of dexmedetomidine which was intravenously infused over 10 min.HR and mean arterial pressure were monitored and recorded before administration (T0) , and at 15 and 40 min after administration (T1,2).The correlation between doses of dexmedetomidine and change rate of HR was tested by Spearman correlation analysis.Results In vitro experiment Compared with group C, no significant changes were found in HR and LVSP at each time point in D1 and D2 groups (P＞0.05).In vivo experiment Compared with those at T0 , HR at T1 in D6 and D9 groups, HR at T1,2 in D12 and D15 groups, and mean arterial pressure at T1,2in D6, D9, and D12 groups were significantly decreased (P＜0.05) , and no significant change was found in HR at each time point in group D3 (P＞0.05).The correlation coefficient between doses of dexmedetomidine and change rate of HR was 0.944 (P＜0.05).Conclusion The mechanism by which dexmedetomidine lowers HR of rabbits is not related to direct inhibition of sinoatrial nodes, but associated with the balance of autonomic nervous system.

Morphologic Changes in Autonomic Nerves in Diabetic Autonomic Neuropathy

Diabetic neuropathy is one of the major complications of diabetes, and it increases morbidity and mortality in patients with both type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM). Because the autonomic nervous system, for example, parasympathetic axons, has a diffuse and wide distribution, we do not know the morphological changes that occur in autonomic neural control and their exact mechanisms in diabetic patients with diabetic autonomic neuropathy (DAN). Although the prevalence of sympathetic and parasympathetic neuropathy is similar in T1DM versus T2DM patients, sympathetic nerve function correlates with parasympathetic neuropathy only in T1DM patients. The explanation for these discrepancies might be that parasympathetic nerve function was more severely affected among T2DM patients. As parasympathetic nerve damage seems to be more advanced than sympathetic nerve damage, it might be that parasympathetic neuropathy precedes sympathetic neuropathy in T2DM, which was Ewing's concept. This could be explained by the intrinsic morphologic difference. Therefore, the morphological changes in the sympathetic and parasympathetic nerves of involved organs in T1DM and T2DM patients who have DAN should be evaluated. In this review, evaluation methods for morphological changes in the epidermal nerves of skin, and the intrinsic nerves of the stomach will be discussed.

Regulação autonômica das propriedades mecânicas em bioprótese valvar porcina / Autonomic regulation of mechanical properties in porcine mitral valve cusps / Regulación autonómica de las propiedades mecánicas en bioprótesis valvular porcina

FUNDAMENTO: A presença de nervos nas válvulas cardíacas foi demonstrada pela primeira vez há décadas e identificadas em subpopulações: simpáticas e parassimpáticas, e, portanto, é esperado que as válvulas sejam grandemente afetadas pelos nervos autônomos. Entretanto, poucos estudos têm se concentrado na regulação de válvulas cardíacas pelo sistema nervoso autônomo. OBJETIVO: Buscamos identificar o papel do sistema nervoso autônomo na regulação das propriedades mecânicas dos tecidos de válvulas mitrais porcinas. MÉTODOS: As propriedades mecânicas dos folhetos de válvulas mitrais porcinas foram avaliados em resposta à norepinefrina (NE) e acetilcolina (ACH), os principais neurotransmissores. Ao mesmo tempo, fentolamina (FENT), metoprolol (Metop), atropina (Atrop) e desnudamento endotelial foram adicionados ao sistema reativo. RESULTADOS: Sob condições fisiológicas, a rigidez não foi afetada pelo desnudamento endotelial (p > 0,05). A NE significantemente aumentou a rigidez valvar por aumento de 10 vezes na concentração (10-6 vs 10-7, p < 0,05; 10-5 vs 10-6, p < 0,05). Essa resposta foi amenizada por FENT, Metop ou desnudamento endotelial (p < 0,05); entretanto, manteve-se aumentada de maneira significante quando comparada aos Controles (p < 0,05). A ACH causou uma diminuição na rigidez acompanhada por um aumento em sua concentração (alteração significante na rigidez por aumento de 10 vezes na concentração de ACH, 10-6 vs Controle, p < 0,05; 10-5 vs 10-6, p < 0,05), que foi revertida pelo desnudamento endotelial e Atrop (p > 0,05 vs Controle). CONCLUSÃO: Esses achados ressaltam o papel do sistema nervoso autônomo na regulação das propriedades mecânicas das cúspides de válvula mitral porcina, o que reforça a importância do estado nervoso autônomo no funcionamento ideal da válvula.

BACKGROUND: The presence of nerves in heart valves was first depicted decades ago and identified into subpopulations: sympathetic, parasympathetic. So valves are expected to be greatly affected by the autonomic nerves. However, few studies have focused on the regulation of heart valves by the autonomic nervous system. OBJECTIVE: We sought to identify the role of the autonomic nervous system in the regulation of the mechanical properties of porcine mitral valve tissues. METHODS: Mechanical properties of porcine mitral valve leaflets were evaluated in response to norepinephrine (NE) and acetylcholine (ACH), the main neurotransmitters. At the same time, phentolamine (Phent), metoprolol (Metop), atropine (Atrop) and endothelial denudation were added to the reactive system. RESULTS: Under physiological conditions, the stiffness was not affected by endothelial denudation (p > 0.05). NE elevated the valve stiffness significantly per 10-fold increase in concentration (10-6 vs 10-7, p < 0.05; 10-5 vs 10-6, p < 0.05). This response was mitigated by Phent, Metop or endothelial denudation (p < 0.05), however, it was still increased significantly when compared to Controls (p < 0.05). ACH caused a decrease in stiffness accompanied by an increase in its concentration (significant change in stiffness per 10-fold increase in ACH concentration, 10-6 vs Control, p < 0.05; 10-5 vs 10-6, p < 0.05), which were reversed by endothelial denudation and Atrop (p > 0.05 vs Control). CONCLUSION: These findings highlight the role of the autonomic nervous system in the regulation of the mechanical properties of porcine mitral valve cusps, which underline the importance of autonomic nervous status for optimal valve function.

FUNDAMENTO: La presencia de nervios en las válvulas cardíacas quedó demostrada por primera vez hace algunas décadas e identificadas en sub-poblaciones: simpáticas y parasimpáticas y por lo tanto, lo que se espera es que las válvulas reciban una gran afectación de los nervios autónomos. Sin embargo, pocos estudios se han concentrado en la regulación de válvulas cardíacas a través del sistema nervioso autónomo. OBJETIVO: Buscamos identificar el papel del sistema nervioso autónomo en la regulación de las propiedades mecánicas de los tejidos de las válvulas mitrales porcinas. MÉTODOS: Las propiedades mecánicas de las capas de válvulas mitrales porcinas fueron evaluadas en respuesta a la norepinefrina (NE) y a la acetilcolina (ACH), los principales neurotransmisores. Igualmente, la fentolamina (FENT), el metoprolol (Metop), la atropina (Atrop) y la denudación endotelial también se añadieron al sistema reactivo. RESULTADOS: Bajo condiciones fisiológicas, la rigidez no se afectó por el denudación endotelial (p > 0,05). La NE aumentó significativamente la rigidez valvular con un aumento de 10 veces en la concentración (10-6 vs 10-7, p < 0,05; 10-5 vs 10-6, p < 0,05). Esa respuesta fue amenizada por FENT, Metop o denudación endotelial (p < 0,05); pero se mantuvo aumentada de manera significativa cuando se le comparó con los Controles (p < 0,05). La ACH causó una disminución en la rigidez acompañada por un aumento en su concentración (alteración significativa en la rigidez por el aumento en 10 veces de la concentración de ACH, 10-6 vs Control, p < 0,05; 10-5 vs 10-6, p < 0,05), que fue revertida por la denudación endotelial y Atrop (p > 0,05 vs Control). CONCLUSIÓN: Esos hallazgos destacan el rol del sistema nervioso autónomo en la regulación de las propiedades mecánicas de las cúspides de la válvula mitral porcina, lo que refuerza la importancia del estado nervioso autónomo en el funcionamiento ideal de la válvula.

Mechanism of Interdigestive Migrating Motor Complex

Migrating motor complex (MMC) is well characterized by the appearance of gastrointestinal contractions in the interdigestive state. This review article discussed the mechanism of gastrointestinal MMC. Luminal administration of 5-hydroxytryptamine (5-HT) initiates duodenal phase II followed by gastrointestinal phase III with a concomitant increase of plasma motilin release in conscious dogs. Duodenal 5-HT concentration is increased during gastric phase II and phase III. Intravenous infusion of motilin increases luminal 5-HT content and induces gastrointestinal phase III. 5-HT4 antagonists significantly inhibits both of gastric and intestinal phase III, while 5-HT3 antagonists inhibited only gastric phase III. These suggest that gastrointestinal MMC cycle is mediated via the interaction between motilin and 5-HT by the positive feedback mechanism. Gastric MMC is regulated via vagus, 5-HT3/4 receptors and motilin, while intestinal MMC is regulated via intrinsic primary afferent neurons and 5-HT4 receptors. Stress is highly associated with the pathogenesis of functional dyspepsia. Acoustic stress attenuates gastric phase III without affecting intestinal phase III in conscious dogs, via reduced vagal activity and increased sympathetic activity. It has been shown that subset of functional dyspepsia patients show reduced vagal activity and impaired gastric phase III. The physiological importance of gastric MMC is a mechanical and chemical cleansing of the empty stomach in preparation for the next meal. The impaired gastric MMC may aggravate dyspeptic symptoms following a food ingestion. Thus, maintaining gastric MMC in the interdigestive state is an important factor to prevent the postprandial dyspeptic symptoms.

Effect of negative emotion evocation on autonomic function activity of hearts in healthy population: An empirical study / 第二军医大学学报

Objective To study the effect of negative emotion evocation on the autonomic function activity of hearts in healthy subjects, and to initially discuss the mechanism by which negative emotion is involved in the development of coronary heart disease. Methods We selected 69 healthy university students as our subjects. A computer game was used to induce the stress among them; the skin code, heart rate and heart rate variablity (HRV) were collected and compared at different phases. Results The high frequency (HF) value was significantly decreased(F[2,67] = 10. 773,P<0. 01), the low frequency (LF) value was signficantly increased(F[2, 67] = 5. 620,P<0. 01), and LF/HF ratio was significantly decreased(F[2, 67] = 40. 327, P<0. 01) at both expecting phase and coping phase, which indicates significant changes of cardiac sympathovagal activity, including the relative excitation of sympathetic nerve, relative depresioon of the vagus nerve, and aggravated autonomic imbalance. Conclusion Exposure of healthy individual to acute emotional stress can induce autonomic variation similar to that of coronary heart disease, indicaling that long-term negative emotional stress may be one of the risk factors for vagal dysfunction.

Realistic Anatomical Prostate Models for Surgical Skills Workshops Using Ballistic Gelatin for Nerve-Sparing Radical Prostatectomy and Fruit for Simple Prostatectomy

PURPOSE: Understanding of prostate anatomy has evolved as techniques have been refined and improved for radical prostatectomy (RP), particularly regarding the importance of the neurovascular bundles for erectile function. The objectives of this study were to develop inexpensive and simple but anatomically accurate prostate models not involving human or animal elements to teach the terminology and practical aspects of nerve-sparing RP and simple prostatectomy (SP). MATERIALS AND METHODS: The RP model used a Foley catheter with ballistics gelatin in the balloon and mesh fabric (neurovascular bundles) and balloons (prostatic fascial layers) on either side for the practice of inter- and intrafascial techniques. The SP model required only a ripe clementine, for which the skin represented compressed normal prostate, the pulp represented benign tissue, and the pith mimicked fibrous adhesions. A modification with a balloon through the fruit center acted as a "urethra." RESULTS: Both models were easily created and successfully represented the principles of anatomical nerve-sparing RP and SP. Both models were tested in workshops by urologists and residents of differing levels with positive feedback. CONCLUSIONS: Low-fidelity models for prostate anatomy demonstration and surgical practice are feasible. They are inexpensive and simple to construct. Importantly, these models can be used for education on the practical aspects of nerve-sparing RP and SP. The models will require further validation as educational and competency tools, but as we move to an era in which human donors and animal experiments become less ethical and more difficult to complete, so too will low-fidelity models become more attractive.

A prospective study on nerve-sparing radical hysterectomy in patients with cervical cancer / 中华妇产科杂志

Objective To assess the nerve-sparing radical hysterectomy (NSRH) technique and its impact on postoperative voiding function. Methods Forty-fonr patients with International Federation of Gynecology and Obstetrics(FIGO) stage Ⅰ b1 - Ⅱ a cervical cancer were enrolled and randomized into NSRH group ( study group, n = 22) and conventional radical hysterectomy (CRH) group ( control group, n = 22). The pelvic autonomic nerve pathway (including hypogastric nerve, pelvic splanchnic nerve, inferior hypogastric plexus and bladder branch) was completely preserved in the NSRH group. Related parameters were compared between the two groups. Results The estimated blood loss in NSRH group and CRH group were (550±241) ml and (475±284) ml, respectively, with no significant difference (P >0. 05). The mean operation time in NSRH group and CRH group were (329±43) min and (272±56) min, respectively, with a significant difference (P < 0. 01). More patients in NSRH group had post-void residual urine volume (PVR) < 100 ml than that in CRH group on day 8 after surgery (68% vs. 18%, P <0. 01). The median duration of postoperative catheterization was significantly shorter in NRSH group (8 - 23 days, median 8 days) than that in CRH group ( 8 - 32 days, median 20 days; P < 0. 01 ). Neither surgery-related injury nor pathologically positive margin was reported in either of the groups. Conclusions NSRH is a feasible and safe technique for preserving bladder function. Larger prospective studies are needed to confirm the efficacy of this technique.

Ultrastructural Studies of Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the gastrointestinal tract (GIT). Although interstitial cells of Cajal has been suggested as origin of this tumor, the cytological and ultrastructural features of GISTs are heterogeneous and unclear. A total 10 cases of normal gastrointestinal tissue (control), 13 GISTs of the stomach (8), small intestine (3), mesocolon (1) and liver (1), and 2 gastrointestinal autonomic nervous tumor (GANT) of small intestine were ultrastructurally studied. Normal interstitial cells of Cajal (ICC) were abundantly present around the myenteric plexuses or individually scattered through the wall of GIT. ICC was characterized by slender cytoplasmic processes, well-developed endoplasmic reticulum (ER), mitochondria, Golgi apparatus, caveolae and intermediate filaments. The GISTs and GANTs had overlapping ultrastructures. The most common and important ultrastructural features of GISTs were rich villous cytoplasmic processes, dispersed intermediate filaments and abundant SER, and those of GANTs were neurosecretory granules and skenoid fibers. Compared with ICC, the GISTs and GANTs had remarkably reduced caveolae and gap junctions. Our study suggested that ultrastructural analysis gives much information to investigate lineage differentiation of neoplastic cells and make a differential diagnosis of these tumors from other mesenchymal tumors and between GISTs and GANTs.

The anatomy of pelvic autonomic nerves and experience on preserving autonomous nerves during surgery of rectal cancer / 中国普通外科杂志

Objective To study the anatomy of pelvic autonomic nerves, to avoid autonomic nerves damage during rectal cancer surgery. MethodsAnatomical dissections were carried out on 7 adult cadavers, and clinically autonomic nerve-preserving rectal cancer resection was performed. Results The superior hypogastric plexus lies just posterior to the inferior mesenteric vessels. There were no obvious autonomic nerve trunks in the loose areolar tissue plane between the parietal fascia and the visceral fascia right posterior to the rectum. There were no obvious autonomic nerve trunks between the rectum and the seminal vesicles or the prostate. The inferior hypogastric plexus was a rhomboid shaped plaque of nervous tissue. The main components of the lateral ligament were autonomic nerves passing from the pelvic plexus to the rectum within a condensation of connective tissue. WT5”HZConclusionsThe inferior mesenteric vessels can be used a landmark intraoperatively to identify the superior hypogastric plexus. In order to preserve the inferior hypogastric plexus while dissecting the lateral of rectum, we should dissect along the medial surface of the inferior hypogastric plexus, and along its curvature. JP2

Comparison of atrial fibrillation inducibility due to electrical stimulation of the extrinsic vs the intrinsic cardiac autonomic innervation / 中国介入心脏病学杂志

Objective To investigate the influence of cervical vagosympathetic trunk or ganglionated plexi stimulation to the inducibility of atrial fibrillation(AF) in dogs.Methods In 16 anesthetized dogs,right cervical vagosympathetic trunk(VST) were dissected.A right thoracotomy was used to expose fat pad(FP) containing the ganglionated plexi(GP) at the caudal end of the sinus node.An electrode catheter was attached along the right superior pulmonary vein to allow programmed atrial pacing.At 2?,4? and 10? threshold atrial refractory periods(ARPs) were determined with and without VST or GP stimulation.At each pacing threshold AF inducibility was measured from the window of vulnerability(WOV).A cumulative WOV sum made of all WOVs was calculated in each group.Results In the baseline state the heart rate(HR) averaged 153?22 beats/min.Slowing of the HR by VST stimulation(79?44 beats/min) was not significantly different than with GP induced slowing(87?99 beats/min,P=NS).Furthermore,there were no significant differences between the lowest ARPs with VST stimulation and GP stimulation,accounting to 90?17 ms and 91?13 ms respectively(P=NS),but both are shorter than that in the baseline state,which was 101?20 ms(P

Spontaneous focal atrial fibrillation arising from a peripheral atrial site:separation of AF triggers from AF maintenance / 中国介入心脏病学杂志

10 minutes).The average cycle length(CL) at the RAA was 30.6?4.6 msec vs.105.2?32.0 msec at other atrial sites(P