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S Nosaka

Publications and source records attributed to S Nosaka.

At least 73 records · Page 4Linked to original sources
PubMed1996

A prejunctional mechanism in midbrain periaqueductal gray inhibition of vagal bradycardia in rats.

Stimulation of the dorsal part of the midbrain periaqueductal gray matter (dPAG) inhibits baroreflex vagal bradycardia (BVB) via a central mechanism. Here we report that the dPAG suppresses vagal bradycardia also by a peripheral mechanism. In chloralose-urethan-anesthetized, beta-blocked rats, the cervical vagus nerve was cut and the distal cut end was electrically stimulated to induce vagal bradycardia (VIB). Sustained electrical stimulation of the dPAG attenuated VIB in a duration-dependent manner but did not affect bradycardia induced by intravenous acetyl-choline (AIB). The dPAG inhibition of VIB was abolished by C1 transection. Intravenous norepinephrine (NE) reduced VIB but did not affect AIB. Both the dPAG and NE inhibitions of VIB were largely attenuated during intravenous prazosin, a selective alpha 1-receptor antagonist. In contrast, BVB provoked by aortic depressor nerve stimulation was remarkably inhibited by a shortly preceding dPAG stimulation, but this inhibition was not affected by C1 transection. Prazosin treatment did reduced the inhibition, but only moderately. In conclusion, the dPAG has a potential ability to suppress VIB by prejunctionally inhibiting acetylcholine release from cardiac vagus nerve terminals via alpha 1-receptors. However, dPAG stimulation first suppresses BVB largely at a central site, leaving a limited fraction of vagal outflow to be inhibited by a prejunctional mechanism operating with long latency.

Acetylcholine↗
PubMed1996

Modifications of arterial baroreflexes: obligatory roles in cardiovascular regulation in stress and poststress recovery.

Despite the physiological importance of arterial baroreflexes as a powerful stabilizer of blood pressure, their functions themselves are not always stable and there are a variety of circumstances in which they are significantly modulated. During stressful conditions, including fight/flight, defense/attack, somatic nociception, visceral nociception, exercise, and mental stress, arterial baroreflexes are generally inhibited. The inhibition is purposeful for achieving dynamic readjustment of circulation needed for the animal's reaction to cope with these conditions. Central sites which are proposed to be involved in the inhibition include the motor cortex, amygdala, hypothalamus, dorsolateral part of the periaqueductal gray matter, parabrachial nucleus, cerebellar vermis, etc. On the other hand, arterial baroreflexes are occasionally facilitated, during sleep, following endurance exercise, etc. The facilitation favors restoration of energy exhausted during a stressful phase in which the animal reacts actively to changing environment. The central sites proven to elicit the facilitation are the medial prefrontal cortex, the preoptic/anterior hypothalamus, the ventrolateral part of the periaqueductal gray matter, and the nucleus raphe magnus. The inhibition and facilitation of arterial baroreflexes, which probably occur alternatively, are essential mechanisms supporting reactions to stressful conditions and poststress recovery, respectively. This review describes when, how, and why the arterial baroreflexes are so modulated.

Animals↗
PubMed1996

[Two operated cases of synchronous double cancer of the lung and digestive tract in patients over 80 years old and genetical diagnosis].

Synchronous double cancer of the lung and gastrointestinal organ was successfully resected by an one-step approach in two aged patients over 80 years. An 81-year-old man was clinically diagnosed as having a right lung cancer (S3) along with a sigmoid colon cancer. The pathological cell types of these cancers were squamous cell carcinoma and adenocarcinoma respectively. Right upper lobectomy and sigmoidectomy were performed at the same time because he had no risks for the operation. An-80-year-old woman was diagnosed as having a left lung cancer (S8-9) along with a stomach cancer. The cell types of these cancers were both highly differentiated adenocarcinoma. Left lower lobectomy and subtotal gastrectomy were performed at the same time, too. We limited lymph nodes dissection to shorten the operation time and no postoperative complications occurred in both patients. It is suggested that simultaneous operation for double cancer in aged patients can be safely performed in selected cases. In the latter patient, pathological cell type of the lung cancer was similar to that of stomach cancer. So we applied polymerase chain reaction (PCR) for making a diagnosis of double cancer postoperatively, and it was proved that the lung and gastric cancers were different from each other in genetical natures. Application of the genetical technique to clinical field which greatly contribute to making a diagnosis of double cancer is expected.

Adenocarcinoma↗
PubMed1996

[Constrictive pericarditis with dissecting aortic aneurysm (DeBakey type II)].

We experienced a case of constrictive pericarditis with dissecting aortic aneurysm (DeBakey type II). The patient complained of orthopnea and leg edema. The cause of constrictive pericarditis was pericardial effusion due to dissecting aortic aneurysm. Ascending aortic replacement with graft and decortication of thickened pericardium were performed. We confirmed the decrease of CVP and PAP intraoperatively. Postoperative course was uneventful.

Aged↗
PubMed1996

[A reused suction catheter was broken and produced a tracheobronchial foreign body].

We present a rare case involving a broken suction catheter that became lodged in the tracheobronchial tree. An eight-month-old infant was scheduled for hernioplasty. Following intubation with a 4 French (Fr.) endotracheal tube, a 5 Fr. reused suction catheter was applied for suctioning a moderate amount of secretion. This catheter had been resterilized by ethylene oxide gas (EOG). Insertion of the catheter into the tube was not done smoothly, and we could not obtain any secretion. During the extraction of the suction catheter by force, the catheter broke. The distal fragment (20 cm length) seemed to have been lodged in the tracheobronchial tree. Prior to its removal by bronchoscopy, the endotracheal tube was extubated. Fortunately the remaining part of the catheter come out with the tube. Ten cm of the fractured catheter was included in the tube and 5 cm protruded from the tube. The catheter of smaller diameter is easy to be broken even by weaker force. After resterilization by EOG for once, there was no change in length and force at breaking point. Elongation of the broken catheter (85.5%) was less compared with the new sample (155%). At the breaking point, half of the cross section was very smooth and looked as if it had been cut by a razor, while the other half appeared to have been broken by pulling. The break may have started from the crack which had occurred at the insertion or resterilization. Therefore, we should restrict the reuse of small suction catheters, and should always utilize the catheter of the largest size possible.

Anesthesia, Inhalation↗
PubMed1996

[Long-term survival after treatment of thoracic aneurysms by thromboexclusion operation].

Since 1982, fourteen patients with aortic aneurysms received thromboexclusion operation. This method was performed in 7 patients with dissecting aortic aneurysms, 6 patients with true thoracic aneurysms, and 1 patient with true thoracoabdominal aneurysm. Among them, 12 patients received the operation of ascending aorta-supraceliac abdominal aorta bypass, one patient received descending aorta-descending aorta bypass, and another one received bilateral axillo-iliac artery bypass. Graft sizes in diameter were from 16 mm to 22 mm. 9 patients received permanent paired-clamps at both the proximal and the distal parts of the thoracic aneurysm, and 5 patients received permanent single-clamp only at the proximal part of the thoracic aneurysm. 5 patients (35.7%) died perioperatively because of low output syndrome, cerebral infarction, hepato-renal insufficiency, and aneurysmal rupture, respectively. 4 late deaths (28.6%) occurred after 4 months, 5 months, 26 months, and 5 years of operation, respectively. Among them, three deaths were due to aneurysmal rupture and one due to heart failure. Although paired-clamps at both the proximal and the distal parts of the thoracic aneurysm were performed in 1 to 3 ruptured-cases, thrombo-occlusion of the thoracic aorta did not occur in any of the cases. Long-term survival was 35.7% in 5 patients after 14 years and 4 months of mean follow-up. Although a single-clamp only at the proximal part of the thoracic aneurysm was performed in 2 of these 5 cases, thrombo-occlusion of the thoracic aorta occurred in all cases. For the four survivors of them, we ran a follow-up survey and found left ventricular hypertrophic pattern in ECG, concentric left ventricular hypertrophy in UCG, and hypertension, but those were absent before operation. We conclude that thromboexclusion method for thoracic aneurysm should be limited only to high-risk patients particularly in bad conditions or to cases with severe adhesion to lung which seem to be inaccessible through direct approach.

Adult↗
PubMed1996

[Anesthetic management of a child with pheochromocytoma using sevoflurane, diltiazem and continuous epidural blockade].

A 13-year-old girl with pheochromocytoma was anesthetized for the resection of the tumor. We selected sevoflurane as an inhalation anesthetic in combination with continuous epidural blockade. We administered diltiazem mainly to control hypertension but severe hypertension during the manipulation of the tumor was difficult to control. However, systemic vascular resistance was maintained at a low level and there was no arrhythmia during surgery. This report suggests that the use of diltiazem provides a stable hemodynamic condition for the removal of pheochromocytoma.

Adolescent↗
PubMed1996

[A successful case of infrarenal abdominal aortic replacement against acute abdominal organ failures and ischemia of bilateral lower limbs following the operation of DeBakey IIIb-type dissecting aneurysm].

We experienced a successful surgical case, who was a 52-year-old man suffered from acute abdominal organ failures and ischemia of bilateral lower limbs following aortic arch replacement against DeBakey IIIb-type dissecting aneurysm. We investigated the abdominal blood flow by DSA via true lumen, which seemed to be obstructed by the increase in blood flow to false lumen. Therefore, to increase in blood flow to true lumen, we performed an urgent infra-renal abdominal aortic replacement successfully.

Abdomen↗
PubMed1996

[A case of malignant esophageal stenosis with esophagobronchial fistula treated with a covered wallstent].

A polyurethane-covered Wallstent was used for a esophagus cancer patient with malignant esophageal stenosis associated with esophagobronchial fistula. Stent placement was successfully performed with no procedure related-complications. Following the procedure the patient could eat a normal diet. The insertion of a polyurethane-covered Wallstent is a safe and effective treatment for malignant esophageal stenosis with esophagobronchial fistula.

Bronchial Fistula↗
PubMed1995

Ischemic preconditioning improves cardiac functional recovery following preservation with University of Wisconsin solution.

Single or multiple brief periods of regional or global ischemia and reperfusion prior to a prolonged ischemic insult showed cardioprotective effects. Although this phenomenon (ischemic preconditioning [IPC]) has been described in ischemic reperfusion models, the effect of IPC on heart preservation has not been previously reported. We, thus, investigated the effect of IPC on heart preservation. Hearts isolated from male Wistar rats (250-350 g) were mounted on a Langendorff apparatus to estimate baseline function (aortic flow, coronary flow, cardiac output, heart rate, systolic pressure, and rate pressure product). All hearts were divided into 5 groups. In groups 1 and 4, the hearts were subjected to 8 and 12 hr of preservation, respectively. The hearts in group 2 were subjected to a single 2.5-minute cycle of normothermic global ischemic episode (IPC) before 8 hr of preservation. In groups 3 and 5, the hearts were subjected to two 2.5-min IPC cycles and stored for 8 or 12 hr. The hearts were arrested with University of Wisconsin solution and stored at 4 degrees C. Following storage, the hearts were reperfused and measured postpreservative function to assess cardiac functional recovery. Lactate and troponin-T leakage in the coronary perfusate was also measured. In group 3, the treatment of two 2.5-min IPC cycles significantly increased cardiac output, but the treatment of single 2.5-min IPC cycle did not affect the result. In the extended preservation group (group 5), the recovery (%) of both coronary flow and cardiac output were significantly increased compared with group 4. Furthermore, lactate leakage was significantly reduced in groups 2 and 3. These results suggest that IPC improves cardiac functional recovery following simple cold storage and has cardioprotective effects in rat heart preservation.

Adenosine↗
PubMed1995

Facilitation of the arterial baroreflex by the preoptic area in anaesthetized rats.

1. Activation of cell bodies in the ventrolateral part of the midbrain periaqueductal grey matter (PAG) facilitates the arterial baroreflex via the nucleus raphe magnus. The facilitatory effects of stimulation within the hypothalamus on the arterial baroreflex and their relation to the PAG and nucleus raphe magnus were studied in urethane- and chloralose-anaesthetized rats. 2. Systematic mapping experiments revealed that the preoptic area (POA) is the principal location in the hypothalamus of neuronal cell bodies that are responsible for the potentiation of the baroreflex. In addition to provoking hypotension and vagal bradycardia, both electrical and chemical stimulation of the POA produced facilitation of baroreflex vagal bradycardia (BVB) that was evoked by electrical stimulation of the aortic depressor nerve. Baroreflex hypotension was slightly augmented during activation of the POA in vagotomized rats. 3. Selective destruction of cell bodies either in the ventrolateral PAG or in the nucleus raphe magnus reduced facilitation of BVB by the POA. Hypotension and bradycardia due to POA stimulation were also markedly attenuated after such selective destruction. 4. In conclusion, the POA, the ventrolateral PAG and the nucleus raphe magnus constitute a functional complex that produces cardiovascular trophotropic effects including hypotension, vagal bradycardia and baroreflex facilitation.

Anesthesia↗
PubMed1995

'Aortic baroreceptor' neurons in the nucleus tractus solitarius in rats: convergence of cardiovascular inputs as revealed by heartbeat-locked activity.

Rat aortic depressor nerve (ADN) contains only baroreceptor afferents. We identified 'aortic baroreceptor' neurons in the nucleus tractus solitarius (NTS) as those responding to electrical stimulation of the ADN and attempted to demonstrate convergence of cardiovascular mechanoreceptor inputs in these 'baroreceptor' neurons. In chloralose-urethane-anesthetized rats, ADN stimulation evoked either short or long latency responses (SLR, LLR) in 193 neurons of the NTS. 28 (SLR, 15; LLR, 13) demonstrated ongoing activities with cardiac rhythm despite the fact that the ADN had been cut peripherally. In 12 (SLR, 5; LLR, 7) of the 28 neurons, heartbeat-locked activity was abolished by carotid occlusion (CO), and augmented by methoxamine-induced blood pressure elevation, indicating that the heartbeat-locked activity originated from carotid sinus baroreceptors (CSB). In 11 neurons (SLR, 6; LLR, 5), the heartbeat-locked activity was not affected by CO but was abolished by topical application of lidocain on the ipsilateral cervical vagus, suggesting that the heartbeat-locked activity originated mostly from cardiac mechanoreceptors. The origin of the heartbeat-locked activity of the remaining 5 neurons could not be determined. The onsets, as well as peaks of the heartbeat-locked activity of vagal origin appeared significantly earlier than those of CSB origin. In conclusion, NTS neurons receive converging projection not only from the two major arterial baroreceptors but also from the arterial baroreceptors and cardiac mechanoreceptors, thereby integrating sensory information of vascular and cardiac origins.

Animals↗
PubMed1995

Doppler ultrasonographic evaluation of hepatic circulation in patients following Kasai's operation for biliary atresia.

The hepatic circulation of eight children who underwent Kasai's operation for biliary atresia was serially evaluated by Doppler ultrasonography (US). A total of 36 examinations were performed to evaluate the maximal velocities (mvs) of the main portal vein (MPV), splenic vein (SV), and hepatic artery (HA), and to analyze the spectral waveform and the directions of flow. The mean mvs-MPV in four patients for whom adequate biliary diversion had been achieved and whose serum bilirubin had fallen to within the normal range (group A), was 19.8 +/- 7.5 cm/s. Their MPV waveforms were constant, with blood flowing toward the liver, while their mean mvs-SV was 12.1 +/- 5.8 cm/s. In two other patients with apparent hypersplenism, but whose serum bilirubin levels had fallen to nearly normal (group B), the mean mvs-MPV was 20.7 +/- 10.4 cm/s and the mvs-SV was 22.4 +/- 10.4 cm/s. In contrast, the mvs-MPV in the two remaining patients, whose serum bilirubin levels had either not fallen to within the normal range, or had fallen initially but increased due to recurrent cholangitis (group C), was 14.2 +/- 9.1 cm/s. In these patients, the waveforms were unstable, the MPV flows were occasionally hepatofugal, and their mean mvs-SV was 18.0 +/- 5.8 cm/s. The mvs-HA were markedly increased in the latter four patients, whose clinical condition had also deteriorated. These observations led to the conclusion that hepatic circulation evaluated by serial Doppler US provides important information about liver status in children who have undergone Kasai's operation for biliary atresia.

Adolescent↗
PubMed1995

Comparative study of the mammalian liver innervation: an immunohistochemical study of protein gene product 9.5, dopamine beta-hydroxylase and tyrosine hydroxylase.

The liver innervation of eight different mammalian species was examined by immunohistochemical localization of protein gene product (PGP) 9.5 to visualize the general innervation for autonomic nerve fibres. In addition, dopamine beta-hydroxylase (DBH) and tyrosine hydroxylase (TH), two enzymes involved in catecholamine synthesis, were localized immunohistochemically to delineate hepatic sympathetic nerve fibres. We found that: (1) Within the interlobular region of each species, PGP 9.5, DBH and TH-positive nerve fibres were all seen in close association with branches of hepatic arteries, portal veins and bile ducts. (2) Within the parenchyma of the guinea-pig, cat, dog, pig, monkey and human liver, the presence of the three immuno-positive nerve fibres could be unequivocally identified, although the density of these intralobular fibres showed marked species variation. Moreover, immunoelectron microscopic study confirmed that PGP 9.5-positive nerve terminals of the human liver are in close apposition to hepatocytes. (3) In mouse and rat, no parenchymal nerve fibres immunoreactive for PGP 9.5, TH or DBH could be demonstrated.

Adult↗
PubMed1995

[The use of high concentration ferric ammonium citrate (FAC) solution as a negative bowel contrast agent: application in MR cholangiography].

Ferric ammonium citrate (FAC) can be used as a negative contrast agent on T2- weighted images, with the use of a high concentration resulting in a significant T2 shortening effect. Ten healthy volunteers underwent MR cholangiography (MRC) using Turbo Spin Echo. High-concentration FAC was administered at a normal dosage, but was diluted in a smaller amount of water than usual. Although all precontrast images showed high intensity intestinal fluid, which aggravated visualization of the bile duct, all postcontrast images obtained 6 to 14 minutes after administration showed blackening out of the fluid, improving the overall image quality of MRC.

Adult↗