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Biomedical subjects

K Kagawa

Publications and source records attributed to K Kagawa.

At least 19 recordsLinked to original sources
PubMed2004

DNA modification in chick heart and cerebrum.

Heart muscle cells and cerebral neurons are known to lose the ability to proliferate and are called terminally differentiated cells. They are generated in appropriate numbers during embryogenesis and retained throughout adult life without turnover. We are interested in such a long-lived DNA. We isolated DNA from chick heart and cerebrum and compared it with DNA from other organs after incubation with DNase I. Single-strand breaks were assessed using a reaction system composed of DNA and Escherichia coli DNA polymerase. The DNA of both organs was relatively resistant to DNase I, and DNA modification occurred during embryogenesis. CIMS (chemical ionization mass spectrometry) indicated that the molecular mass of the deoxynucleoside of both DNAs was larger than that of the corresponding canonical deoxyribonucleoside by m/z 28 (or 30 for the protonated form). The difference between these deoxynucleosides is based on a difference in sugar constituents. Cerebral deoxynucleotides were analyzed by (13)C NMR. An extra signal near 173 ppm was observed, which was assigned to the amide carbonyl. We propose a model of the deoxynucleoside where a carbonyl residue exists between the base and the 2-deoxyribose moiety of the canonical deoxyribonucleoside.

Animals↗
PubMed2001

Diabetes attenuates the minimum anaesthetic concentration (MAC) and MAC-blocking adrenergic response reducing actions of clonidine in rats.

BACKGROUND: It is well known that clonidine, an alpha2 agonist, reduces anaesthetic requirement and attenuates haemodynamic responses against noxious stimuli. However, the diabetic state is known to affect several functions of alpha2 adrenoceptors. We investigated the effects of streptozotocin (STZ)-induced diabetes mellitus (DM) on these beneficial actions of clonidine in halothane-anaesthetized rats. METHODS: The rats were randomly assigned to one of three groups: diabetes (n=24, induced by 50 mg x kg(-1) IV STZ), diabetes treated with insulin (n=24), or control (n=24). We evaluated the effects of clonidine on minimum anaesthetic concentration (MAC) and minimum concentration of halothane needed to suppress cardiovascular responses evoked by a noxious stimulus (MAC-blocking adrenergic responses: MAC-BAR) in each group. MAC and MAC-BAR of halothane were determined by the tail clamp method. MAC-BAR was defined as the MAC which attenuated haemodynamic responses within 10% following the tail clamp. RESULTS: The diabetic state decreased MAC of halothane by approximately 10%, while MAC-BAR of halothane had been little affected. In the diabetes group, MAC reducing action of clonidine (30 and 100 microg x kg(-1), IV) was completely abolished and MAC-BAR reducing action of clonidine was partially reduced (30 but not 100 microg x kg(-1), IV). Insulin treatment preserved these actions of clonidine. CONCLUSION: It is suggested that the diabetic state attenuates the beneficial actions of clonidine and that insulin treatment of diabetes preserves these actions of clonidine.

Adrenergic alpha-Agonists↗
PubMed2001

Evaluation of diagonal earlobe crease as a marker of coronary artery disease: the use of this sign in pre-operative assessment.

In this study, we examined the usefulness of the earlobe crease sign as a marker of coronary artery disease in the pre-operative assessment of patients. We were interested in evaluating this sign for use in emergency patients. We investigated 530 patients, aged > 40 years, undergoing elective surgery. If the electrocardiogram was abnormal or the patient reported symptoms suggesting coronary artery disease, further cardiac examinations were performed. Patients who demonstrated evidence of coronary artery disease in the additional investigations or had a clear history of coronary artery disease were classified as the abnormal coronary group. Other patients with no history and/or normal investigations were classified as the normal coronary group. The assessment of earlobe crease sign was performed prior to anaesthesia, and the sensitivity, specificity and positive predictive value of this sign were calculated. We found that the sensitivity and specificity was high regardless of age, except for specificity in patients > 70 years old. The data suggest that the earlobe crease sign may be a useful marker for the presence of coronary artery disease in patients undergoing emergency operations in which little or no history and investigations are available. However, more work is required to assess the use of this sign in other ethnic groups.

Adult↗
PubMed2001

Intraaneurysmal embolization of an unruptured basilar tip aneurysm associated with moyamoya disease.

We describe a patient with moyamoya disease associated with an unruptured basilar tip aneurysm which was treated by endovascular embolization using Guglielmi detachable coils (GDCs). A 53-year-old man presented with left hemiparesis persisting for 3 mon ths before admission. Cerebral angiography revealed occlusion of the bilateral middle cerebral arteries and the left anterior cerebral artery, stenosis of the right anterior cerebral artery, and basal moyamoya vessels. In addition, a saccular small aneurysm was seen at the top of the basilar artery. The aneurysm was completely embolized by intraaneurysmal GDCs. Direct surgical clipping is often selected for the treatment of posterior fossa aneurysms in moyamoya disease. However, complete clipping is usually difficult due to the difficulties in operative technique associated with moyamoya disease. We suggest that the endovascular treatment using GDCs is comparatively safe and effective for the treatment of surgically difficult aneurysms in patients with moyamoya disease.

Cerebral Angiography↗
PubMed2001

Syndrome of inappropriate secretion of ADH (SIADH) following cisplatin administration in a pulmonary adenocarcinoma patient with a malignant pleural effusion.

We report a patient with pulmonary adenocarcinoma complicated by the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) following systemic chemotherapy with cisplatin (CDDP) and vindesine (VDS). A 66-year-old woman was diagnosed as having pulmonary adenocarcinoma with malignant pleural effusion following investigations for cough and dyspnea. After drainage of the effusion she received combination chemotherapy with CDDP and VDS. She developed SIADH 48 hours following chemotherapy. Interestingly, the use of carboplatin (CBDCA) and VDS in the subsequent treatment course was well tolerated indicating that the SIADH was most likely to have been induced by administration of CDDP.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed2001

Hypervascular liver metastasis from hypovascular ductal cell carcinoma of the pancreas.

In a case of hypervascular metastatic liver tumor, the vascularity of primary focus, pancreatic carcinoma was hypovascular. Based on the imaging findings, we thought before the operation that the two lesions were double cancers. Histological examination showed that the stromal volume of metastatic tumorous tissue was richer than that of the primary focus. It was suggested that the difference in the stromal volume was related to the difference of the vascularity. Some foctors originating in stromal cells might be involved in angiogenesis.

Carcinoma, Pancreatic Ductal↗
PubMed2001

Arrhythmogenic effect of hypercapnia in ducks anesthetized with halothane.

OBJECTIVE: To determine effects of hypercapnia on arrhythmias in ducks anesthetized with halothane. ANIMALS: 12 ducks, 6 to 8 months old, weighing 1.1 to 1.6 kg. PROCEDURES: Each duck was anesthetized with a 1.5% mixture of halothane in oxygen, and anesthetic depth was stabilized during a 20-minute period. We added CO2 to the inspired oxygen to produce CO2 partial pressures of 40, 60, and 80 mm Hg in the inspired gas mixture.The CO2 partial pressure was increased in a stepwise manner. When arrhythmias were not evident during inhalation of the gas mixture at a specific CO2 partial pressure, the CO2 partial pressure was maintained for 10 minutes before a sample was collected for blood gas analysis. When arrhythmias were detected, a sample for blood gas analysis was collected after the CO2 partial pressure was maintained for at least 2 minutes, and CO2 inhalation then was terminated. RESULTS: During the stabilization period, PaCO2 (mean +/- SD) was 33 +/- 5 mm Hg,and arrhythmias were not detected. In 6 ducks, arrhythmias such as unifocal and multifocal premature ventricular contractions developed during inhalation of CO2. Mean PaCO2 at which arrhythmias developed was 67 +/- 12 mm Hg. In 5 of 6 ducks with arrhythmias, the arrhythmias disappeared after CO2 inhalation was terminated. CONCLUSION AND CLINICAL RELEVANCE: Analysis of data from this study indicated that hypercapnia can lead to arrhythmias in ducks during halothane-induced anesthesia. Thus, ventilatory support to maintain normocapnia is important for managing ducks anesthetized with halothane.

Anesthesia, Inhalation↗
PubMed2001

[Cavernous sinus dural arteriovenous shunt presenting with subarachnoid hemorrhage and acute subdural hematoma: a case report].

Cavernous sinus dural arteriovenous shunt (CdAVS) usually presents with exophthalmos, conjunctival chemosis, ophthalmoplegia, headache, bruit, or pulsatile tinnitus. Intracranial hemorrhage associated with CdAVS is rare. We describe a patient with CdAVS presenting with subarachnoid hemorrhage and acute subdural hematoma. A 65-year-old woman presented headache and temporary loss of consciousness and was transferred to our hospital. On admission, the patient was alert and complained of a left-sided temporal headache. There were no ocular symptoms. A CT scan revealed subarachnoid hemorrhage and left acute subdural hematoma. When we prepared for cerebral angiography, the patient presented loss of consciousness following sudden onset of severe headache. Urgent angiography revealed left CdAVS, which was fed by both the internal carotid artery and the external carotid artery and drained only into ipsilateral (left) vein of the sylvian fissure. Aneurysmal dilatation of the draining veins and leptomeningeal drainage were present. No cerebral aneurysms were detected. After the angiography, a CT scan showed enlarged subdural hematoma, so left fronto-temporo-parietal craniotomy was immediately performed. On opening the dura mater, arterial bleeding from Sylvian fissure appeared and was uncontrollable. Unfortunately, the patient died 3 days after the operation. We concluded that subarachnoid hemorrhage and subdural hematoma were due to the rupture of engorged cortical veins. Our case report suggests that CdAVS with angiographic findings such as aneurysmal dilatation of the draining veins and leptomeningeal drainage should be treated urgently because of the high risk of the life-threatening complications resulting from a surgically uncontrollable hemorrhage.

Aged↗
PubMed2000

alpha-eudesmol, a P/Q-type Ca(2+) channel blocker, inhibits neurogenic vasodilation and extravasation following electrical stimulation of trigeminal ganglion.

In this study, we investigated the effect of alpha-eudesmol, which potently inhibits the presynaptic omega-agatoxin IVA-sensitive (P/Q-type) Ca(2+) channel, on neurogenic inflammation following electrical stimulation of rat trigeminal ganglion. Treatment with alpha-eudesmol (0.1-1 mg/kg. i.v.) dose-dependently attenuated neurogenic vasodilation in facial skin monitored by a laser Doppler flowmetry. In addition, alpha-eudesmol (1 mg/kg. i.v.) significantly decreased dural plasma extravasation in analysis using Evans blue as a plasma marker. On the other hand, alpha-eudesmol (1 mg/kg, i.v.) did not affect mean arterial blood pressure in rats. The calcitonin gene-related peptide (CGRP) and substance P (SP) released from activated sensory nerves have recently been suggested to be associated with the neurogenic inflammation. In this study, we also showed that alpha-eudesmol (0.45-45 microM) concentration-dependently inhibits the depolarization-evoked CGRP and SP release from sensory nerve terminals in spinal cord slices. These results indicate that the anti-neurogenic inflammation action of alpha-eudesmol, which does not affect the cardiovascular system, may be due to its presynaptic inhibition of the neuropeptide release from perivascular trigeminal terminals. We also suggest that the omega-agatoxin IVA-sensitive Ca(2+) channel blocker, alpha-eudesmol, may become useful for the treatment of the neurogenic inflammation in the trigemino-vascular system such as migraine.

Animals↗
PubMed2000

omega-agatoxin IVA-sensitive Ca(2+) channel blocker, alpha-eudesmol, protects against brain injury after focal ischemia in rats.

omega-Agatoxin IVA-sensitive Ca(2+) channels have been thought to be involved in physiological excitatory amino acid glutamate release and these channels may also contribute to the development of ischemic brain injury. Recently, we demonstrated that alpha-eudesmol from Juniperus virginiana Linn. (Cupressaceae) inhibits potently the presynaptic omega-agatoxin IVA-sensitive Ca(2+) channels. In the present study, we investigated the effects of alpha-eudesmol on brain edema formation and infarct size determined after 24 h of reperfusion following 1 h of middle cerebral artery occlusion in rats. We first found that alpha-eudesmol concentration-dependently inhibited glutamate release from rat brain synaptosomes and that its inhibitory effect was Ca(2+)-dependent. In the middle cerebral artery occlusion study, intracerebroventricular (i.c.v.) treatment with alpha-eudesmol significantly attenuated the post-ischemic increase in brain water content. alpha-Eudesmol also significantly reduced the size of the infarct area determined by triphenyltetrazolium chloride staining after 24 h of reperfusion. Using a microdialysis technique, we further demonstrated that alpha-eudesmol inhibits the elevation of the extracellular concentration of glutamate during ischemia. From these results, we suggest that alpha-eudesmol displays an ability to inhibit exocytotic glutamate release and to attenuate post-ischemic brain injury.

Animals↗
PubMed2000

Treatment of acute right coronary artery occlusion during anesthesia.

PURPOSE: Perioperative coronary artery occlusion is a potentially dangerous complication causing myocardial infarction and circulatory collapse. We report a case showing severe ST segment depression in leads II and V5 during anesthesia. Diltiazem and nifedipine, but not nitroglycerine, partially improved the ST changes which were normalized by a percutaneous cardiopulmonary system (PCPS). CLINICAL FEATURES: A 71-yr-old man with cerebrovascular disease was scheduled for coronary artery bypass grafting (CABG). Past medical history included myocardial infarction due to right coronary artery (RCA) occlusion. Both the femoral artery and vein were cannulated percutaneously before operation and the PCPS was prepared as a back-up system. Depression of the ST segments in leads V5 and II was observed following heparinization. Although hemodynamic stability was maintained with continuous infusion of catecholamines, the ST changes were not improved by intravenous nitroglycerine. Intravenous diltiazem followed by nasal nifedipine partially improved the ST changes. The changes were normalized after induction of PCPS. No neurological complications were observed. The postoperative coronary angiography confirmed the total occlusion of RCA. CONCLUSION: Calcium channel blockers were more effective than nitroglycerine in treating perioperative ST depression. However, none of them produced complete reversal of the ischemic changes which were normalized with PCPS.

Acute Disease↗
PubMed2000

Body position does not influence the location of ventilator-induced lung injury.

OBJECTIVE: To ascertain whether the locations of ventilator-induced lung injury (VILI) are influenced by body position. DESIGN: Randomized prospective short-term study. SETTING: Animal laboratory at a university school of medicine. INTERVENTIONS: Twelve white rabbits were mechanically ventilated in IMV mode with an infant ventilator (V.I.P. Bird, Bird Products, Palm Springs, Calif., USA). Based on the results of a preliminary study to determine the ventilator settings at which the lungs of rabbits were injured within 5 h in the supine position, the ventilator was set at F(I)O2 0.21, at a rate of 30/min, T(I) 0.6 s, peak inspiratory pressure 30 cm H2O, inspiratory flow 10 l/min with no applied positive end-expiratory pressure (PEEP). Six of the animals were tested in the supine position and the other six in the prone position. Respiratory gases were measured and CT scanning was performed every 30 min. The animals were ventilated for 5 h or until pulmonary parenchymal opacification was detected. The lungs were divided into three areas from apex to base and three levels from ventral to dorsal, and the location of opacification was ascribed according to this scheme. After the experiment, the lungs were excised and examined histologically. MEASUREMENTS AND RESULTS: Parenchymal opacification occurred mainly in the dorsal lung areas. The time from the beginning of ventilation to the appearance of lung damage was 60-120 min in the supine (S) group, and 60-270 min in the prone (P) group, and it was significantly longer in the prone group (P < 0.01). We observed diffuse lung damage, including hyaline membrane formation, intra-alveolar edema, and infiltration of inflammatory cells. CONCLUSIONS: Body position affected the time course of the development of VILI, but it did not affect the location.

Analysis of Variance↗
PubMed2000

Reduction of peritonitis with the rectus abdominis muscle flap in a CAPD patient.

An adolescent maintained on continuous ambulatory peritoneal dialysis (CAPD) for 8 years had relapsing peritonitis involving peritoneal catheter tunnel infections. We attempted catheter removal and replacement simultaneously, with the catheter covered cylindrically by a rectus abdominis muscle flap to prevent recurrent tunnel infections. During 3 years of follow-up, there have been no episodes of peritonitis involving tunnel infection. Our modified insertion technique can eradicate tunnel infection, thus reducing peritonitis.

Adolescent↗
PubMed2000

Supraspinal, not spinal, alpha(2) adrenoceptors are involved in the anesthetic-sparing and hemodynamic-stabilizing effects of systemic clonidine in rats.

UNLABELLED: Clonidine, an alpha(2) agonist, reduces the anesthetic requirement and attenuates harmful hemodynamic responses to noxious stimuli. We examined the responsible sites of action in the central nervous system for the minimum alveolar anesthetic concentration (MAC) and MAC blocking adrenergic response (MAC-BAR) reducing effects of systemically administered clonidine in halothane-anesthetized rats. The MAC for halothane was determined by the tail clamp method, and MAC-BAR was defined as the MAC which attenuated hemodynamic responses within 10% after the tail clamp. We examined the effect of IV clonidine in the presence of rauwolscine, an alpha(2) antagonist given through IV, intrathecal (IT), intracisternal (IC), or intracerebroventrical (ICV) routes. IV clonidine reduced MAC and MAC-BAR dose-dependently. IV and ICV rauwolscine antagonized the MAC-reducing effect of clonidine, whereas IC and IT rauwolscine did not. In comparison, IV, ICV, and IC rauwolscine antagonized the MAC-BAR-reducing effect of clonidine; IT rauwolscine had no effect. Our data demonstrate that the alpha(2) adrenoceptors in the regions above mesencephalon and both the regions above mesencephalon and the lower brainstem are responsible for the MAC and MAC-BAR-reducing effect of systemic clonidine in rats, respectively. However, the spinal alpha(2) adrenoceptors were not involved in these effects of clonidine. IMPLICATIONS: In the regions above mesencephalon, alpha(2) adrenoceptors were the most responsible for the minimum alveolar concentration-reducing effect and both the lower brainstem and regions above mesencephalon were involved in the minimum alveolar concentration blocking adrenergic response-reducing effect of clonidine. The spinal alpha(2) adrenoceptors did not significantly contribute to these effects of clonidine.

Adrenergic alpha-Agonists↗
PubMed2000

Artificial ventilation-induced diffuse alveolar damage in rabbits: preliminary study of early detection on expiratory high-resolution computed tomography.

RATIONALE AND OBJECTIVES: To investigate whether expiratory high-resolution computed tomography (HRCT) is more useful than inspiratory HRCT for the detection of early-phase diffuse alveolar damage. METHODS: Eleven anesthetized rabbits were scanned with both inspiratory and expiratory HRCT every 30 minutes during mechanical ventilation. Ten rabbits were killed after the detection of pulmonary abnormalities on both inspiratory and expiratory HRCT. The remaining rabbit was killed when the pulmonary abnormalities appeared only on expiratory HRCT. RESULTS: In four cases (36%), the abnormal findings were detected earlier on expiratory HRCT than on inspiratory HRCT. In seven cases (64%), the abnormalities appeared simultaneously on inspiratory and expiratory HRCT. In all 11 cases, the histopathological changes of areas with abnormal CT findings corresponded to the exudative or proliferative phase of diffuse alveolar damage. CONCLUSIONS: Expiratory HRCT has the potential to detect the abnormalities of diffuse alveolar damage earlier than inspiratory HRCT.

Acute Disease↗
PubMed2000

Telemedicine system for home automated peritoneal dialysis.

We have developed a new telemedicine system to monitor elderly and handicapped patients that use an automated peritoneal dialysis (APD) system to perform continuous ambulatory peritoneal dialysis (CAPD) at home. The system has two parts: (1) a data collection and transport system, and (2) an interview system ("View Send" system). The former is assembled from the APD cycler, an automated blood-pressure recorder, and a scale. The latter is a combination of a digital camera, television, and set-top box (a kind of computer). The APD system contains recording and data transport junctions, a monitoring device, and a data tabulation function. All data collected by the APD system are sent directly in real time to the physician's office. Patients can easily use this telemedicine system to contact the medical staff at the Saitama Medical School CAPD center and to consult concerning their condition. Furthermore, the staff can directly change the CAPD schedule (dose and duration). Seven patients, including some who are older than 90 years or who are handicapped, have been using this telemedicine system for between 1 and 6 months (average: 3 months). From our recent experience, our tentative conclusions are that (1) elderly and handicapped patients benefit from this system by being able to maintain CAPD without major problems and accidents; (2) other problems are mainly due to simple mistakes such as accidentally pushing the on and off switches; (3) quality of life is improved for the patients.

Aged↗