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Biomedical subjects

S Nosaka

Publications and source records attributed to S Nosaka.

At least 109 records · Page 6Linked to original sources
PubMed1993

[A new leak test of anesthetic machine].

A case of the inspired PCO2 increase secondary to the malfunction of expiratory valve due to a defected edge of creator is presented. In this case, we could not detect the malfunction of expiratory valve using the preanesthetic routine leak test but found it by observing the expiratory phase of the capnometric curve. Therefore, we devised a new leak test for checking the malfunction of inspiratory and expiratory valves. This test is simple and effective. The test consists of the following procedures.: 1. Connecting yokes to the oxygen piping system. 2. Connecting the breathing bag. 3. Occluding the inspiratory terminal. Closing the semiclosed valve completely. 4. Flushing the O2 gas and increasing the pressure of breathing circuit to 30 cmH2O. 5. Monitoring the pressure gauge of the anesthesia system. If the function of valves is normal, the system pressure decreases slowly. If either of the valves works wrong, it decreases rapidly. We checked anesthesia machines in our facilities using the new leak test, and found some cases of the expiratory valve malfunctions.

Adenocarcinoma↗
PubMed1993

[A case report of cardiac failure caused by the new anti-neoplastic agent 'carboplatin'].

Carboplatin is one of most commonly used chemotherapeutic agents in clinical oncology practice. We presented a case of subacute cardiotoxicity supposedly due to carboplatin. A patient with ovarian cancer had been treated with carboplatin based chemotherapeutic agent for about a month before surgery. Although she had not shown symptoms of cardiac failure, severe pulmonary edema developed immediately after general anesthesia. It disappeared within a week. For three days following the administration of carboplatin alone for two weeks after surgery, arrhythmias (SVT, SVPB and VPB) and hypotension appeared. Symptoms of congestive heart failure, resembling dilated cardiomyopathy, lasted for one month. It required about two months to restore the normal cardiac functions. Carboplatin seems to have infrequent but possible cardiotoxicity as many other chemotherapeutic agents.

Carboplatin↗
PubMed1992

Effects of local anesthetics on the Chara plasmalemma.

The effects of lidocaine, tetracaine, procaine and bupivacaine (less than 1000 microM) on the Chara corallina internodal cell were studied. These local anesthetics depolarized the membrane at rest, while they affected the rising phase and the peak level of action potential not appreciably. Instead, they prolonged the time course of the falling phase of action potential as slowly as the repolarization was imperfect, even after enough lapse beyond the refractory period. Consequently, an action potential appeared to enhance the degree of depolarization at rest. Such a depolarization with stimulus/excitation was named use-dependent depolarization, while the depolarization without excitation, the resting one. The order of the potency of the use-dependent depolarization almost coincided with that of the nerve-blocking potency. During depolarization the change in membrane conductance was not simple. However, the conductance-voltage (Gm-Vm) relationship curve in the presence of local anesthetic suggested that depolarization was due to, not only the decrease in the electrogenic H(+)-pump, but also the increase in the diffusion conductance.

Action Potentials↗
PubMed1991

Arterial baroreflex inhibition by gastric distension in rats: mediation by splanchnic afferents.

Arterial baroreflexes are known to be reset during activation of defense area and somatosensory receptors-afferents. Here we report that viscerosensory activation also inhibits the baroreflexes. In chloralose-urethan-anesthetized, succinylcholine-immobilized, and artificially ventilated rats, the aortic depressor nerve was electrically stimulated while propranolol was continuously infused to elicit baroreflex hypotension (BH) and baroreflex vagal bradycardia (BVB). Hydraulic distension of the stomach with warm 0.9% NaCl solution was found to suppress BVB and BH, with a threshold intraluminal pressure at times less than 5mmHg. The gastric distension also suppressed BH in atropinized rats, suggesting that inhibition involved not only cardiac but also vascular components of baroreflexes. Bilateral splanchnectomy largely attenuated the inhibition, whereas bilateral subdiaphragmatic vagotomy had little effect. Low- as well as high-frequency stimulation of the splanchnic nerve strongly suppressed both BVB and BH, whereas only low-frequency stimulation of the subdiaphragmatic vagus inhibited baroreflexes to a slight degree. In conclusion, gastric distension suppresses BVB and BH, and this inhibition is largely mediated by afferent fibers in the splanchnic nerve. Such baroreflex inhibition may be a general consequence of mechanoreceptor activation of any visceral hollow organs because the jejunum, esophagus, and urinary bladder were all found to suppress arterial baroreflexes when distended.

Animals↗
PubMed1990

[Occlusion of fistulas with fibrin glue].

Fistula formation is one of complications after surgery. Additional surgical intervention is recommended when fistula does not respond to conservative therapy. Eight patients with fistula were treated by using a baby feeding tube or double lumen angiographic catheter with fibrin glue. All the fistulas except one were successfully treated; 6 with complete occlusion and one with decreased discharge from fistula. It is emphasized that two deep fistulas could be occluded by using angiographic technique. Our preliminary result suggests fibrin occlusion therapy of fistulas is a safe and useful procedure, and an alternative to surgery for non-curative fistula.

Aged↗
PubMed1990

Some characteristics of a peptidyl dipeptidase (kininase II) from rat CSF: differential effects of NaCl on the sequential degradation steps of bradykinin.

Incubation of various authentic peptides with rat CSF in vitro and analysis of their products by HPLC demonstrated the presence in CSF of a peptidyl dipeptidase [peptidyl dipeptide hydrolase; angiotensin I converting enzyme (ACE); kininase II; EC 3.4.15.1] which sequentially degraded bradykinin (BK) by liberating the carboxy-terminal dipeptides and converted angiotensin I to angiotensin II. This CSF enzyme was gel-chromatographed by means of HPLC, and the molecular weight was estimated. The susceptibility to various peptidase inhibitors of the rat CSF enzyme, as well as the effect of NaCl on the degradation of BK and Hip-His-Leu catalyzed by it, was also determined. These properties were compared with those of ACE or kininase II from brain or other tissues, as described in the literature. NaCl was shown to exert specific and concentration-dependent effects on each step of the sequential degradation of BK, via BK(1-7) to BK(1-5), catalyzed by the enzyme. In addition, the enzyme system for metabolism of BK appears to differ between rat CSF and blood, the former containing exclusively kininase II, whereas the latter contains both kininase I (carboxypeptidase N; EC 3.4.12.7) and kininase II.

Animals↗
PubMed1990

[Skin blood flow measured by laser Doppler flowmetry under enflurane anesthesia or modified neuroleptanesthesia during abdominal surgery].

In 18 patients for abdominal operations, the skin blood flow of the sole was measured with a laser Doppler flowmeter under general anesthesia. The deep body temperature was also measured. During the induction of anesthesia with thiopental, an elevation of the skin blood flow was observed. The elevation was due to administration of thiopental. After the induction, the elevation appeared to be more prolonged under nitrous-oxide and enflurane anesthesia than under diazepam or droperidol, with nitrous-oxide and fentanyl anesthesia. The persistent elevation was observed for 104 +/- 10 minutes under enflurane anesthesia in 10 patients, but the elevation was 71 +/- 7 minutes under modified neuroleptanesthesia in 8 patients. This difference might be associated with the peripheral vasodilatation by enflurane and the short peripheral vasodilatation by droperidol or diazepam. Increases of the skin blood flow correlated well with the changes of the deep temperature of the sole. These results indicate that the peripheral skin blood flow is different during long operation between enflurane anesthesia and modified neuroleptanesthesia and the laser Doppler flowmetry is a useful tool as a monitor of peripheral circulation and body temperature.

Abdomen↗
PubMed1989

Somatosensory and hypothalamic inhibitions of baroreflex vagal bradycardia in rats.

Somatosensory and forebrain mechanisms inhibiting arterial baroreflexes were investigated in chloralose-urethane anesthetized and artificially ventilated rats. Electrical stimulation of the sciatic nerve (ScN) and the hypothalamic pressor area (HP) suppressed baroreflex vagal bradycardia (BVB) and hypotension provoked by electrical stimulation of the aortic depressor nerve (ADN). Suppression of BVB was more marked, but inhibitory potencies of ScN and HP were not different. These two inhibitions were considered to have a functional implication in common, since both were accompanied by increase in hindlimb vascular conductance. A variety of experiments were conducted to localize the target site of ScN and HP inhibitions of BVB. Either ScN or HP stimulations was without effect on antidromic compound spike potentials along ADN evoked by microstimulation of the nucleus tractus solitarius (NTS), precluding the possibility of these inhibitions being presynaptic. Both ScN and HP stimulation suppressed ADN-induced field potentials in the NA region which provoked vagal bradycardia upon microstimulation, but failed to affect ADN-induced responses, either field or unitary, in the NTS region. Antidromic unitary responses in the NA region to vagus cardiac branch stimulation were suppressed by ScN and HP stimulations in NTS-lesioned rats. Intracisternal bicuculline, a GABA antagonist, was found to abolish both ScN and HP inhibitions of BVB, while intracisternal muscimol, a GABA agonist, eliminated bradycardia. These findings suggest that somatosensory and forebrain inhibition of BVB occur principally at the preganglionic cell level and are probably mediated by a GABAergic mechanism.

Animals↗
PubMed1989

Somatosensory inhibition of vagal baroreflex bradycardia: afferent nervous mechanisms.

Sensory receptors, afferent fibers, and spinal ascending pathways involved in somatosensory inhibition of baroreflex vagal bradycardia (BVB) were studied in chloralose-urethan-anesthetized rats. BVB was induced by electrical stimulation of the aortic depressor nerve (ADN). Among mechanical and thermal stimuli applied on a hindlimb, hot water (55 degrees C) immersion was most effective to inhibit BVB. Static hindlimb muscle contraction by ventral root stimulation also produced BVB inhibition that was abolished by muscle relaxation. These findings suggest that thermal nociceptors and muscle receptors, probably chemoreceptors, trigger BVB inhibition when activated. Furthermore, afferent fiber groups responsible for BVB inhibition due to sciatic nerve (ScN) or sural nerve (SU) stimulation were determined. BVB was largely inhibited by activation of A delta-fibers of the ScN or SU, but C-fiber contribution to BVB inhibition was also ascertained by means of selective C-fiber activation. Finally, courses of spinal pathways mediating ScN inhibition of BVB were localized as follows. First, ADN-vagal baroreflex arc of one side was interrupted by unilateral vagotomy. Then ScN inhibition of BVB provoked by the remaining reflex arc was analyzed after spinal cord hemisection at C1 and subsequent lesioning of the cord on the nonsectioned side. Regardless of whether the spinal cord was hemisectioned on any side with respect to the target reflex arc, stimulation of the ScN of either side still inhibited BVB, unless the lateral funiculus of nonsectioned side was extensively lesioned. In conclusion, the spinal BVB-inhibitory pathways are multifold, projecting to bilateral baroreflex vagal centers by crossing the midline at spinal or/and medullary levels.

Afferent Pathways↗
PubMed1989

[Uncommon renal tumor in children].

We experienced six rare cases of solid renal tumor, which include two benign (CMN, MLCN) and four malignant tumors (CCSK 2, MRTK2). CMN is the most common benign solid tumor in the neonate. MLCN has typical US or CT findings manifested by multilocular cysts and thick wall septa. CCSK and MRTK are rare malignant neoplasms, which present characteristic clinical findings such as bone metastasis or intracranial metastasis. It is important for the radiologist to understand those characteristic clinical presentation of these tumors, because differential diagnosis is often impossible just on the basis of imaging.

Age Factors↗
PubMed1989

[Interventional radiology of benign bile duct diseases].

The authors describe percutaneous interventional procedure for bile duct benign disease from our own experiences and review of the literatures. Percutaneous dilatation of bile duct stricture is widely employed but is associated with 20-30% recurrence rate. It may be the limitation of present procedure and controversy still exists about long-term post dilatation stent. Self-expandable stainless steel stent have potential advantage and it's future development is expected. Percutaneous removal of common bile duct from percutaneously placed biliary drainage is not routine procedure. Endoscopic sphincterectomy is preferred as initial non-surgical treatment. But recent technological improvement makes this technique safe and simple. Balloon dilatation of Ampullar of Fater and extraction of stone into the duodenum is a effective alternative to endoscopic sphincterectomy. Percutaneous removal of multiple intrahepatic stones with choledochoscopic guidance is well accepted method. Adequate selection of access route and balloon dilatation of multiple stenosis are essential for a success. Extra-corporal shock wave lithotripsy is one adjunct in difficult cases.

Adult↗
PubMed1989

Smooth muscle contraction and local anesthetics: calmodulin-dependent myosin light-chain kinase.

Myocardial depressant action of local anesthetics at toxic concentrations is well documented. Their effect on vascular smooth muscle, however, remains controversial. This study analyzed local anesthetic action on the subcellular smooth-muscle contractile system. Highly purified smooth-muscle myosin and myosin light-chain kinase (MLCK) were prepared from fresh turkey gizzards, and the phosphorylation of the myosin light-chain in the presence of Ca++ and calmodulin was evaluated by the urea gel-electrophoresis. Tetracaine 1.3.10(-3) M and bupivacaine 7.5.10(-3) M inhibited the MLCK 50%, whereas lidocaine 2.5.10(-2) M inhibited the MLCK 40%. The inhibitory action was partially reversed by increasing the calcium ion concentration from 1.10(-5) to 2.10(-4) M. On the other hand, raising the calmodulin concentration from 1.10(-7) M to 6.10(-7) M completely reversed the inhibition. A possible cause of the discrepancy in the anesthetic concentrations between subcellular and in vivo studies is discussed.

Bupivacaine↗
PubMed1988

High pressure and anesthesia: pressure stimulates or inhibits bacterial bioluminescence depending upon temperature.

Although high pressure is often viewed as a nonspecific stimulus counteracting anesthesia, pressure can either excite or inhibit biological activity depending on the temperature at application. Temperature and pressure are two independent variables that determine equilibrium quantity, e.g., the state of organisms in terms of activity and anesthesia depth. We used the light intensity of luminous bacteria (Vibrio fischeri) as an activity parameter, and studied the effects of pressure and anesthetics on the bacteria's light intensity at various temperatures. The light intensity was greatest at about 30 degrees C at ambient pressure. When the system was pressurized up to 204 atm, the temperature for maximum light intensity was shifted to higher temperatures. Above the optimal temperature for the maximal light intensity, high pressure increased the light intensity. Below the optimal temperature, pressure decreased light intensity. Pressure only shifts the reaction equilibrium to the lower volume state (Le Chatelier's principle). When the volume of the excited state is larger than the resting state, high pressure inhibits excitation, and vice versa. Halothane 0.008 atm and isoflurane 0.021 atm inhibited the light intensity both above and below the optimal temperature. When pressurized, the light intensity increased in the high temperature range but decreased in the low temperature range, as in the control. Thus, high pressure seemingly potentiated the anesthetic action at low temperatures. When the ratio of the light intensity in bacteria exposed to anesthesia and those not exposed to anesthesia was plotted against the pressure, however, the value approached unity in proportion to the pressure increase.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗
PubMed1986

Electrophysiologic identification of preganglionic neurons in rat dorsal motor nucleus and analysis of vagus afferent projections.

Electrophysiological studies on preganglionic neurons (PGNs) in the dorsal motor nucleus (DMN) of the vagus nerve has been hampered by technical limitations. Conventional electrical stimulation of the vagus nerve with cathodal square-wave pulses activates both preganglionic and afferent fibers. Thus, some PGNs cannot be identified because the anticipated antidromic responses would be blocked due to collision with those orthodromic responses evoked with shorter latencies by activation of fast-conducting afferent fibers. Projections of vagus afferent fibers to PGNs are difficult to analyse with conventional methods because a preceding antidromic response may affect an orthodromic response which has a slightly longer latency. A new stimulation method was designed, consisting of anodal triangular pulse stimulation and spontaneous-spike triggered stimulation. In chlorase-urethane-anesthetized rats, unitary responses of the DMN to electrical stimulation of the ipsilateral vagus nerve were recorded. When only an orthodromic response by a DMN neuron was recorded with conventional stimulation, application of anodal triangular pulse stimulation revealed an antidromic response, so that the cell in question could be identified as a PGN. Some neurons that produced only an antidromic response to conventional stimulation, revealed an orthodromic response on spontaneous-spike triggered stimulation, which blocked the antidromic response due to collision. With these procedures, orthodromic responses due to vagus afferent projections were recorded in 35% of the identified PGNs, mostly due to C and partly, A fiber activations. All these projections were polysynaptic in nature. In conclusion, one-third of the PGNs of the DMN are involved in vagovagal reflexes, which occur through multisynaptic pathways.

Afferent Pathways↗