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Biomedical subjects

S Nosaka

Publications and source records attributed to S Nosaka.

At least 91 records · Page 5Linked to original sources
PubMed1995

[A case report of left atrial free-floating ball thrombus in a patient without mitral valve disease].

A 77-year-old man who had a left atrial free-floating ball thrombus without mitral valve disease was operated. His electrocardiogram showed atrial fibrillation. Transesophageal echocardiography showed free-floating mass in dilated left atrium and intact mitral valve. Transesophageal echocardiogram was also useful for intra-operative management. At the operation, the mass proved to be a free-floating ball thrombus in the left atrium and the intact mitral valve was confirmed. The thrombus was removed, but we could not wean the patient from extra-corporeal circulation due to intra-operative myocardial infarction. Autopsy showed left ventricular hypertrophy and the focus of acute myocardial infarction in lateral wall and posterior wall of left ventricle. Furthermore, large organized thrombi were found in aorta and right main pulmonary artery. It was suggested that the patient had abnormal coagulative system or fibrolytic system preoperatively.

Aged↗
PubMed1995

[A successful operation for left atrial myxoma and mitral valve regurgitation with giant LA].

A 78-year-old woman was introduced to our clinic, complaining of orthopnea and severe appetite loss, and her performance status was evaluated as NYHA IV. Computed tomogram revealed a myxoma in left atrium (LA) as a low density area and MRI demonstrated a high intensity shadow. Left ventriculogram and color Doppler echocardiogram showed severe mitral valve regurgitation (MR) with giant LA. LA myxoma was completely resected through both LA-tomy and RA-tomy. The LA was plicated according to the method reported by Kawazoe, followed by a mitral valve replacement with SJM 25 mm, and a tricuspid annuloplasty according to the DeVega's method. The postoperative course was uneventful and her performance status improved to NYHA II at discharge. LA myxoma frequently causes secondary MR. In this case, however, the LA myxoma did not affect the function of mitral valve, judging from its size and position. There were a few reports about LA myxoma complicated with primary MR. We also confirmed that a LA plication was very useful for the treatment of giant LA to improve a respiratory failure.

Aged↗
PubMed1995

[High concentration ferric ammonium citrate (FAC) solution as a negative bowel contrast agent].

Various concentrations of ferric ammonium citrate (FAC) solution were scanned with conventional SE, Turbo SE (TSE) and STIR sequences on a 0.5-T MR unit. High-concentration FAC solution showed significant signal loss on T2-weighted images. Signal loss was more prominent on heavily T2-weighted images with longer TR/TE using the TSE sequence. T1-weighted images did not show significant signal loss even with high-concentration solution. On STIR images, remarkable signal loss occurred at twice the concentration that had a T1 value similar to fat. We concluded that high-concentration FAC solution may employ as a negative contrast agent in upper abdominal MR imaging.

Abdomen↗
PubMed1995

[A case of lung scar cancer with special pathohistological feature and high CA 19-9 level].

A 58-year-old woman complained of cough and fever. CX-P and chest CT revealed pneumonic shadow and serum CA 19-9 level was high. Since the malignant cells were found in the bronchial lavage fluid, the lower lobectomy of the left lung was done. Both macroscopically and microscopically, adenocarcinoma only existed in 2-3 mm width at the peripheral site of the scar lesion. The postoperative CA 19-9 values continued to be high, suggesting the recurrence of the cancer. After 23 months from the first operation, the upper lobe of the left lung was resected on the base of the similar findings in CX-P and chest CT. The histological finding of the specimen was compatible with the scar cancer described above. After the second operation, the serum CA 19-9 value decreased to normal. We reported a case of the lung scar cancer with special pathohistological feature.

Adenocarcinoma, Papillary↗
PubMed1995

[Perioperative management of dialysed patients for orthopedic surgery].

Recently, renal osteodystrophy is a remarkable problem in patients on long-term hemodialysis (HD). In this retrospective study, we evaluated the perioperative management of 21 patients receiving orthopedic surgery between January 1990 and December 1992. These patients had been maintained on HD for an average of 8.6 years (range, 18 months-20 years). The primary causes of orthopedic surgery were amyloidosis, diabetic gangrene, rheumatoid arthritis and fractures. Laminectomy, replacement of arthropathy, osteosynthesis and amputation of the lower extremity were undertaken. General anesthesia was performed on six patients. Vecuronium was given to all of these patients. Isoflurane was used in 5 patients and sevoflurane in 1 patient. Regional anesthesia was used in 15 patients. During anesthesia, the average infusion rate of intravenous fluids was 2.7 ml.kg-1.h-1, and the intraoperative complications included hypertension in 16, hypotension in 12, arrhythmia in 4 and prolonged sedation in 2 patients. Postoperative complications included hyperkalemia in 2, pneumonia in 2, psychological disorder in 3, clotting fistula in 1 and delayed wound healing in 7 patients. One early death in a diabetic patient following amputation occurred on the 13th postoperative day. Preoperative HD was performed within 24 hours and postoperative HD within 72 hours of the operation. Nafamostat mesilate was used as an anticoagulant. Excessive removal of potassium must be avoided during preoperative HD to prevent arrhythmia. The well-managed elective patients gave a good result. However, extreme care in nutrition and infection control should be taken, especially in diabetic patients.

Anesthesia↗
PubMed1995

[Acute thrombosed aortic dissection--its clinical manifestation and treatment for Stanford A type].

Ten patients (mean age of 63 years old) with acute thrombosed aortic dissection (ATAD) have been evaluated among 31 aortic dissections during past 10 years (from 1985 to 1995). The six cases are Stanford A type and others are Stanford B type. The mean maximal diameter of aorta was 52 +/- 6 mm in Stanford A type and 41 +/- 4 mm in Stanford B type. The ratio of true lumen was 78 +/- 14% to that of whole horizontal section area in thrombosed type and 34 +/- 19% in opacified type dissection. We had chosen conservative treatment for all ATAD. However, five patients with Stanford A type dissection needed to be operated on in short term periods. Three patients were operated upon within three days from onset, and another two patients were operated on 34th and 37th day from onset, respectively. ATAD is firstly treated medically and its prognosis is generally well. However, we proposed here that the conservative treatment for ATAD, especially Stanford A type dissection, must be reconsidered because of our many operations for ATAD in the follow-up periods.

Acute Disease↗
PubMed1995

[Ultrasonography of pediatric right lower abdominal pain: correlation with clinical and pathological results].

Right lower abdominal pain is a common problem in the pediatric population. Ultrasonography (US) is a well-accepted imaging modality in the clinical management of this problem. One hundred and six consecutive pediatric patients with right lower abdominal pain were prospectively evaluated. There were 54 boys and 52 girls, with ages ranging from 3 to 15 years (mean: 9.9 years). Final diagnoses were established based on pathological findings or clinical follow-up. US had sensitivity of 90%, specificity of 98%, and accuracy of 94% in the diagnosis of acute appendicitis. Among all true negative cases (n = 55), there was a variety of US findings other than appendiceal abnormality in 21 cases including intestinal and/or mesenteric (n = 19), gallbladder (n = 1), and ovarian (n = 1) abnormalities. All 21 cases were managed medically without complication. We conclude that US of pediatric right lower abdominal pain is a reliable imaging modality not only for the diagnosis of surgical cases but for eliminating the unexpected surgical intervention.

Abdominal Pain↗
PubMed1995

[Minimizing of the blood preparation for elective surgery by maximum surgical blood order schedule as well as type and screen--two year's experience in Nagahama City Hospital].

To make the most of the blood products, we have introduced maximum surgical blood order schedule (MSBOS) as well as Type and Screen (T&S) into Nagahama City Hospital. As the hospital dose not have blood transfusion service unit, we, anesthesiologists set up MSBOS and the procedure of blood preparations for elective surgery. The results of two year's experience demonstrate that there was no trouble by reducing the blood preparation. The cross-match to transfusion ratio (C/T ratio) in surgical procedures and that of red cell products in our hospital have decreased, the effective use of red cell products has been promoted, and the outdating of the blood product has been reduced.

Blood Loss, Surgical↗
PubMed1994

Facilitation of the arterial baroreflex by the ventrolateral part of the midbrain periaqueductal grey matter in rats.

1. The effects of stimulation of the ventrolateral part of the midbrain periaqueductal grey matter (PAG) on the arterial baroreflex were investigated in urethane-chloralose anaesthetized and artificially ventilated rats. 2. Both electrical and chemical stimulation of the ventrolateral PAG provoked hypotension, vagal bradycardia and marked facilitation of baroreflex vagal bradycardia (BVB), which was induced by stimulation of the aortic depressor nerve. The magnitude of ventrolateral PAG facilitation of BVB was 328 +/- 193% (n = 34) for electrical stimulation and 243 +/- 224% (n = 13) for chemical stimulation. Baroreflex hypotension was slightly augmented during either electrical or chemical stimulation of the ventrolateral PAG in vagotomized rats. 3. Stimulation of the nucleus raphe magnus (NRM) also provoked hypotension, vagal bradycardia and facilitation of BVB. The magnitude of BVB facilitation was 234 +/- 132% (n = 8) for electrical stimulation and 328 +/- 170% (n = 7) for chemical stimulation. After microinjection of kainic acid into the NRM region, baroreflex facilitation, as well as hypotension and vagal bradycardia, produced by ventrolateral PAG stimulation, was almost abolished. 4. In conclusion, the ventrolateral PAG, besides producing hypotension and bradycardia, facilitates arterial baroreflexes. These effects are exerted via the NRM, sharply contrasting with effects of the dorsal PAG.

Animals↗
PubMed1994

Arterial baroreflex inhibition by uterine distension in rats.

Arterial baroreflexes are inhibited during activation of some viscero-sensory receptors. The present study was designed to determine whether stimulation of mechanoreceptors of the uterus also inhibits the baroreflex bradycardia (BB). The aortic depressor nerve (ADN) was electrically stimulated to elicit BB in chloralose/urethane-anesthetized, succinylcholine-immobilized, and artificially ventilated rats. Hydraulic distension of the uterus with warm 0.9% NaCl solution was found to suppress BB with a threshold intra-uterine pressure of 25-100 mmHg. The inhibition was variably affected by successive transections of the hypogastric nerve (HgN) and the pelvic nerve (PN). In 6 rats out of the 16 tested, preceding transection of either HgN or PN (HgN, 4; PN, 2) abolished the inhibition, whereas in 8 rats the inhibition was not affected by preceding transection of either nerve but was abolished by subsequent transection of the other nerve (PN, 3; HgN, 5). In 2 rats, preceding HgN or PN section reduced the inhibition and subsequent PN or HgN section completed the withdrawal of the inhibition. Recording study confirmed that both the HgN and PN contain afferent fibers, signalling mechanoceptive information arising in the uterine wall. Electrical stimulation of the HgN as well as the PN remarkably suppressed the BB. In conclusion, uterine distension suppresses the BB and this inhibition is mediated by afferent fibers running in the HgN and PN with variable contributions among animals. The reflex suppression of BB due to uterine sensory activation may contribute to cardiovascular regulation during parturition.

Animals↗
PubMed1994

Baroreceptor inhibition of the locus coeruleus noradrenergic neurons.

The locus coeruleus is involved in the regulation of blood pressure. The present study was undertaken to address the question of how the blood pressure, in turn, changes the activity of the locus coeruleus neurons via the action of baroreceptors. In chloralose- and urethane-anesthetized rats, the central cut end of the aortic depressor nerve, which does not contain chemoreceptor afferents in this species, was stimulated electrically to excite baroreceptor afferents after bilateral vagotomy and sectioning of the carotid sinus nerve. Single train-pulse stimulation of the aortic depressor nerve provoked the inhibition of ongoing activity in 48% of locus coeruleus neurons tested, but 30% of them responded by excitation with subsequent inhibition. However, when the train-pulse stimulation was repeated with a frequency of 5 Hz, which is close to that of the heartbeat in the rat, all neurons were markedly inhibited. Another series of experiments was conducted in vagotomized and carotid sinus nerve-sectioned rats with intact aortic depressor nerves. When blood pressure was elevated by an intravenous injection of a pressor agent, methoxamine or angiotensin II, or by rapid blood loading, ongoing activities of all locus coeruleus neurons tested were suppressed. In contrast, intravenously injected nitroprusside, a depressor agent, increased the activity of locus coeruleus neurons. In rats with all nerves preserved, rapid blood loading markedly inhibited the activity of these neurons. Such inhibition was partially but significantly attenuated by bilateral sectioning of the aortic depressor nerves.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

[Sick sinus syndrome discovered after induction of general anesthesia in a patient with normal preoperative Holter ECG].

We reported a case of 50-year-old male who was found to have SSS after induction of general anesthesia though his preoperative cardiac function studies including Holter ECG were normal. He was scheduled to have anterior transposition of ulnar nerve for idiopathic ulnar nerve palsy. He had suffered from lung edema during the same operation about 10 months previously at another hospital and the cause had been unknown. We monitored direct radial artery pressure continuously before induction of general anesthesia. About 5 minutes after the induction, ECG showed bradycardia of less than 40.min-1 and systolic blood pressure decreased to 40 mmHg. Intravenous injection of atropine increased heart rate to 60.min-1 only transiently. We began continuous infusion of isoproterenol. It was effective and no bradycardia and hypotension occurred afterwards throughout the operation. About 2 months later, he showed severe dizziness and Holter ECG revealed sinus arrest for 5 seconds. Therefore, a permanent pacemaker was implanted.

Anesthesia, General↗
PubMed1994

[CT & MRI findings of refractory vasculitis].

We described CT and MRI findings of various refractory vasculitis. Refractory vasculitis must be divided into two categories including one group with major vascular involvement and another one with small or microvascular involvement. In cases with major vessel involvement such as Takayasu's arteritis, Kawasaki disease or vasculo-Behçet disease, CT and MRI depicted direct findings of vessels itself including stenosis, obstruction, aneurysm, and wall thickening. On the other hand, CT and MRI showed various extravascular findings in cases with small or microvascular involvement, such as CNS involvement in collagen vascular disease, pulmonary lesions in Wegener's granulomatosis and Churg-Strauss syndrome, and peritoneal lesion in SLE. Our results suggest that CT and MRI findings reflect various vascular condition of refractory vasculitis and correspond to various pathology.

Humans↗
PubMed1993

[Biliary lithotripsy using super fine cholangioscopy with the deviced bended sheath].

Percutaneous transhepatic cholangioscopy (PTCS) is an useful technique to evaluate or treat biliary diseases, although PTCS is an invasive method for the patients. We used 5 F or 7 F of super fine cholangioscopy to treat two cases of choledocholithiasis after surgery without dilatation of drainage tract. We developed different types of bended sheath for supplement of lack of angle system in this cholangioscope. Furthermore, by using bended sheath, cholangioscopic view improved, because saline was injected at the same time via the sheath. We emphasize that super fine cholangioscope with bended sheath is a safe and useful modality for evaluation of biliary disease.

Adult↗
PubMed1993

Chemical stimulation of the nucleus locus coeruleus: cardiovascular responses and baroreflex modification.

Microinjection of glutamate (Glu, 2.5 nmol) or homocysteic acid (HA, 0.1-0.5 nmol) into the nucleus locus coeruleus (LC) decreased both blood pressure and heart rate. These microinjections also produced a facilitatory or occlusive effect on depressor and bradycardiac responses evoked by electrical stimulation of the aortic depressor nerve (ADN). Destruction of the nucleus tractus solitarius (NTS), which totally eliminated ADN-evoked responses, had no effect on the cardiovascular responses evoked by LC stimulation. These results suggest that the neuronal populations that contribute to the LC-induced cardiovascular responses overlap at least partly with the baroreflex substrate other than the NTS.

Animals↗
PubMed1993

Arterial baroreflex inhibition by midbrain periaqueductal grey in anaesthetized rats.

Midbrain periaqueductal grey (PAG) provokes the defense reaction when stimulated. The present study was conducted to determine whether, and how, the PAG produces baroreflex inhibition, a feature characterizing the hypothalamic defense reaction. In chloralose-urethane anaesthetized rats, baroreflex vagal bradycardia and baroreflex hypotension were provoked by aortic depressor nerve stimulation. When the PAG was electrically stimulated baroreflex vagal bradycardia was remarkably suppressed; suppression of baroreflex hypotension was observed following bilateral vagotomy. In contrast, chemical stimulation of the PAG by D,L-homocysteic acid microinjection markedly suppressed baroreflex vagal bradycardia but only minimally suppressed baroreflex hypotension. These findings suggest that whereas overall PAG stimulation inhibits not only cardiac but also vascular components of baroreflexes, inhibition of the latter component either depends largely on activation of passing fibers or requires recruitment of a larger number of PAG cell bodies. PAG inhibition of baroreflex vagal bradycardia was not affected following spinal cord transection at C1, indicating that the inhibition was exclusively central in origin and not due to peripheral, prejunctional inhibition of vagal acetylcholine release by increased cardiac sympathetic nerve activities. The PAG inhibition of baroreflexes was greatly attenuated following electrolytic as well as chemical destruction of the parabrachial region. On the other hand, when the PAG was extensively lesioned, baroreflex inhibition produced by hypothalamic defense area stimulation was markedly diminished. PAG excitation thus causes powerful inhibition of arterial baroreflexes which is mediated by the parabrachial region; the PAG also mediates a major fraction of hypothalamic inhibition of the baroreflexes.

Anesthesia↗
PubMed1993

Target site of inhibition mediated by midbrain periaqueductal gray matter of baroreflex vagal bradycardia.

1. Both electrical and chemical stimulation of the midbrain periaqueductal gray matter (PAG) inhibit baroreflex vagal bradycardia (BVB). The present study was designed to determine the target site of this inhibition about which little is known. Electrical stimulation of the PAG, in particular of its dorsal portion, markedly suppressed BVB provoked by electrical stimulation of the aortic depressor nerve (ADN; percentage of inhibition = 91.0 +/- 9.7%, mean +/- SD; n = 64). To identify the target site of the inhibition, several types of experiments were conducted in rats under chloralose-urethan anesthesia. 2. The inhibition was exclusively of central origin because inhibition of BVB by stimulation of the PAG was unchanged after transection of the spinal cord at the C1 level. According to Wall's method, we examined whether PAG stimulation affects BVB presynaptically by modulating the excitability of ADN terminals in the nucleus tractus solitarius (NTS). However, excitability changes of ADN terminals by the PAG stimulation were not demonstrated. 3. Vagal bradycardia evoked by microinjection of glutamate into the nucleus ambiguus (NA) region was markedly suppressed by the PAG (percentage of inhibition = 85.9 +/- 9.1%; n = 9), an indication that vagal cardiac preganglionic neurons at this site were subject to the inhibitory action of the PAG. Basal vagal tone due to ongoing preganglionic neuronal activity was also subject to inhibitory control by the PAG because basal heart rate was increased by stimulation of the PAG after either C1 transection or NTS lesion. 4. We found that PAG stimulation suppressed ADN-induced field potentials in the NA region (37.7 +/- 13.8% relative to the control; n = 9) but only slightly in the NTS region (95.8 +/- 15.2%; n = 16). In addition, unitary recordings revealed that ADN-evoked unitary responses of neurons in the NA region were suppressed by PAG stimulation, whereas NTS baroreceptor neurons, either ADN responsive or nonresponsive, were scarcely inhibited by PAG stimulation. 5. These findings suggest that the PAG inhibited BVB mainly at the vagal preganglionic cell level and not at the NTS interneuron level. The conclusion is in harmony with our previous reports that the target site of hypothalamic inhibition of BVB in rats is also the preganglionic neurons and that hypothalamic inhibition of BVB is mediated predominantly by the PAG.

Animals↗