Search PubMed⌕ Search

Biomedical subjects

N Okubo

Publications and source records attributed to N Okubo.

At least 19 recordsLinked to original sources
PubMed2001

The relationship of social norms to use of services and caregiver burden in Japan.

PURPOSE: To develop an improved measure of "sekentei" (a social-psychological process that restricts behaviors that do not conform to social norms such as family caregiving) among family caregivers in Japan, and to describe the relationships among sekentei and caregiver's actual use of services, a reluctance to use services, and care burden. DESIGN: Descriptive correlational study. Family caregivers (N = 260) of impaired elders responded to a structured questionnaire. METHODS: Exploratory and confirmatory factor analyses were used to assess the construct validity of the sekentei scale for caregivers (SSC). With the SSC, the relationships among main variables were verified. FINDINGS: The SSC showed satisfactory reliability and validity. Sekentei was significantly correlated with care burden, but not to actual use or reluctance to use services. CONCLUSIONS: Sekentei is an important factor related to caregiver burden in Japan. Further research might include the extent to which sekentei is a factor in care burden in other cultures.

Adult↗
PubMed2001

[Anesthetic management for left ventricular assist device implantation in patients waiting for heart transplantation].

We report the anesthetic management of patients with dilated cardiomyopathy who underwent left ventricular assist device implantation (LVAD). Anesthesia was induced and maintained with midazolam and fentanyl. Transesophageal echocardiography (TEE) and a PA catheter were useful for hemodynamic monitoring and management of the patients. Furthermore, TEE is useful for the early detection of inflow of the air which is absorbed by negative pressure derived from high LVAD support pressure. On starting LVAD support, evaluation of right ventricular function and treatment for right ventricular failure were important and necessary for the patients. Added to conventional therapy using catecholamines, inhaled nitric oxide may provide a favorable effect for right ventricular failure.

Adult↗
PubMed2000

Cardiac troponin I and myocardial contusion in the rabbit.

BACKGROUND: Patients with cardiac contusion have a high risk of cardiac complications during emergency anesthesia. Despite the progress in cardiac imaging, a biologic marker of myocardial damage such as cardiac troponin I remains useful and has been proposed in clinical practice. The relationship among histologic injury, left-ventricular function, and release of cardiac enzymes and cardiac troponin I has been investigated after a controlled myocardial contusion in a rabbit model. METHODS: A global trauma (two levels of energy: 250 and 350 mJ) was produced on an isolated preparation of rabbit's heart, of which the temperature, perfusion flow, beating rate, and left-ventricular volume were kept constant. Left-ventricular pressure and its first derivative as a function of time were measured during a 60-min period after the blow; a timed collection of the effluent was made to assess creatine kinase, lactate dehydrogenase, and cardiac troponin I. At the end of the period, an anatomic score of the contusion was calculated by histologic examination of the hearts. RESULTS: Compared with a control group, the two levels of cardiac trauma resulted in a proportional anatomic injury significantly correlated with left-ventricular dysfunction (Delta%dP/dtmax = -16 +/- 12 and -36 +/- 20% at 3 min, mean +/- SD). Transient releases in cardiac markers after the lesser amount of trauma contrasted with a prolonged and biphasic release of cardiac troponin I after the greater amount. Peak cardiac troponin I level was correlated with anatomic injury (rho = 0.596, P= 0.001) and negatively correlated with left-ventricular dysfunction (r = -0.375, P= 0.04). CONCLUSION: Cardiac troponin I is a marker of anatomic and functional consequences of experimental cardiac trauma and may be a predictive indicator of early posttraumatic cardiac complications during the postoperative period.

Animals↗
PubMed1999

The age-related effects of epidural lidocaine, with and without epinephrine, on spinal cord blood flow in anesthetized rabbits.

UNLABELLED: The effect of epidural or spinal epinephrine when added to local anesthetics on spinal cord blood flow (SCBF)are controversial. We evaluated the effects of epidural lidocaine, with or without epinephrine, on spinal cord blood flow in young and adult rabbits receiving 2% plain lidocaine, 2% lidocaine with epinephrine (1:200,000), or saline epidurally. Colored microspheres were injected through the left ventricle 10 min before and 7.5 and 30 min after epidural injection. The organs (brain, heart, kidneys, and the L6-7 segment of the spinal cord) were analyzed for regional blood flow determination. A significant decrease in mean arterial pressure was observed after the administration of lidocaine, with or without epinephrine, in both adult and young animals compared with saline. SCBF did not change over time in adult rabbits. Conversely, a significant decrease in SCBF was observed in the two groups of young rabbits receiving lidocaine. This decrease correlated with the decrease in mean arterial pressure but did not correlate with the use of epinephrine. We conclude that any reduction in blood pressure occurring in pediatric patients receiving a combined epidural-general anesthetic may result in decreased SCBF. IMPLICATIONS: In young rabbits, any decrease in blood pressure was followed by a decrease in spinal cord blood flow, a decrease that did not correlate to the use of epinephrine and was not observed in adult animals. These data suggest that blood pressure should be monitored closely to promptly treat any decrease in blood pressure when combined epidural-general anesthesia is used in children.

Aging↗
PubMed1996

Translational regulation of angiotensin II type 1A receptor. Role of upstream AUG triplets.

The cDNA sequence of rat angiotensin II type 1A receptor (AT1AR) shows that AT1AR transcripts have AUG triplets in the 5'-leader region that may begin a short open reading frame encoding an 11-amino acid peptide. In this study, the mutational inactivation of the start codon of the short open reading frame in AT1AR-chloramphenicol acetyltransferase (CAT) reporter gene constructs resulted in a 2.6-fold increase in CAT activity, whereas CAT transcript levels were not affected. Furthermore, experiments with rat AT1AR cDNA-transfected Cos-7 cells revealed that mutagenesis of the upstream AUG increased the AT1AR protein up to 2.5-fold, although AT1AR transcript levels showed no changes. The synthetic peptide corresponding to the sequence of the short open reading frame significantly suppressed the amount of AT1AR product in the in vitro translation system. The inhibiting effect of the short open reading frame appears to operate at least in part at the level of translation initiation, because polysome analysis with transfected Cos-7 cells showed that mutagenesis of the upstream AUG resulted in a shift of AT1AR mRNA distribution from a smaller to larger fraction of polysomes. Taken together, these results show that the upstream AUG inhibits translational regulation, suggesting that the short open reading frame in the 5'-leader region of AT1AR transcripts has a certain role in the translation of AT1AR protein.

Animals↗
PubMed1996

[Addition of fentanyl to epidural lidocaine raises the toe temperature].

In order to investigate effects of addition of fentanyl epidurally on the onset of sympathectomy from epidural lidocaine, we have measured the toe temperature of 29 healthy patients undergoing elective lower extremity or lower abdominal surgeries. The latency of onset of the toe temperature was significantly shorter in patients receiving both epidural lidocaine and fentanyl compared with those receiving epidural lidocaine alone (258 +/- 135 vs 398 +/- 184 sec, P < 0.05 [mean +/- SD]). Osmolarity and pH of the epidural solutions were similar between the two groups. These results suggest, but do not indicate, that sympathectomy from epidural lidocaine is accelerated by the addition of fentanyl.

Adult↗
PubMed1995

Characterization of glucocorticoid response element of rat angiotensin II type 1A receptor gene.

The responsiveness of the rat angiotensin II type 1a and type 1b receptor (AT1a-R and AT1b-R) genes to glucocorticoid was examined in rat vascular smooth muscle cells (VSMCs) and the glucocorticoid response element (GRE) of the AT1a-R gene was characterized. Glucocorticoid induced an increase in AT1a-R mRNA levels, whereas AT1b-R mRNA levels were unaffected. The nuclear run-off assay indicated that the transcription of the AT1a-R gene, but not that of the AT1b-R gene, was increased by glucocorticoid. The mRNA stability of AT1a-R was unchanged by glucocorticoid. Promoter/chrolamphenicol acetyltransferase reporter analysis demonstrated that the 5'-flanking region of the AT1a-R gene was functional in rat VSMCs and established that the GRE motif between -770 to -756 could confer glucocorticoid responsiveness on the AT1a-R gene.

Angiotensin II↗
PubMed1995

Spinal anesthesia attenuates myocardial ischemia during coronary artery spasm induced by intraaortic methacholine in rats.

Coronary artery spasm is not rare in patients with coronary artery disease, but the influence of regional anesthesia on spasm-induced myocardial ischemia is not known. We investigated the effects of spinal anesthesia on myocardial ischemia during coronary artery spasm in rats, and compared these with the effects of an alpha- and beta-adrenergic antagonist, and an alpha-adrenergic agonist. An intraaortic catheter was inserted via the right internal carotid artery so that the tip of the catheter was placed near the coronary ostium. An intrathecal catheter was placed at lumbar level. Coronary spasm was induced by the intraaortic injection of methacholine, and we identified the thresholds of myocardial ischemia, defined as the dose of methacholine that induced ST-segment elevation. Subsequently, the thresholds were determined after spinal anesthesia, and after the intraaortic injection of phentolamine and propranolol. The thresholds of myocardial ischemia increased significantly after intrathecal bupivacaine. In contrast, the threshold did not change after the injection of phentolamine. The thresholds increased significantly after the injection of propranolol. Methoxamine significantly decreased the threshold of ischemia. These results demonstrated that spinal anesthesia attenuated myocardial ischemia during methacholine-induced coronary spasm. This effect was equivalent to that of propranolol.

Adrenergic alpha-Agonists↗
PubMed1995

Combined use of glucagon and milrinone may not be preferable for severe propranolol poisoning in the canine model.

In a previous study of propranolol poisoning, glucagon and milrinone significantly increased cardiac output, but the improvement caused by glucagon was almost entirely due to the chronotropic effect. This study investigates the combined effect of glucagon, in a dose not inducing tachycardia, and milrinone on beta-blocker poisoning. Following the administration of 10 mg/kg propranolol IV over ten minutes, dogs (N = 20) were divided into four treatment groups, group S (saline), group G (glucagon 2.5 micrograms/kg), group M (milrinone 100 micrograms/kg), and group G + M (glucagon 2.5 micrograms/kg plus milrinone 100 micrograms/kg). Hemodynamic parameters were observed over the next thirty minutes. Heart rate, cardiac output, and mean arterial pressure were decreased in all groups after the administration of propranolol. Heart rate, mean arterial pressure, cardiac output, and stroke volume recovered to the baseline values in group G + M. However, heart rate in group G + M showed a significant increase versus the other three groups. In a canine model of severe propranolol poisoning, the combined effect of glucagon 2.5 micrograms/kg and milrinone 100 micrograms/kg brought about a significant hemodynamic improvement, but it was accompanied by an excessive increase of heart rate. Combined therapy of milrinone and glucagon may not be preferable therapy in beta-blocker poisoning in the canine model.

Animals↗
PubMed1994

Toe skin temperature as a guide to epidural anaesthesia dosing.

To determine the time for additional epidural anaesthesia, skin temperature of the big toe was evaluated in 50 patients undergoing mastectomy. Epidural catheters were placed at or near the T5-6 intervertebral space and 12 ml, lidocaine 1.5% with 1:200,000 epinephrine were injected. When the skin temperature, which had increased following epidural anaesthesia, decreased by 0.3 degrees C without an increase of systolic arterial blood pressure (ABP) of more than 20%, 8 ml lidocaine 1.5% were injected. If the skin temperature increased, the monitor was judged to have been useful. When ABP increased > 20% without a decrease of skin temperature, the monitor was judged not to have been useful. Monitoring of toe skin temperature was useful in 39 patients (78%) in estimating the time for the first additional dose of epidural anaesthetic. First, second and third intervals between injection were 96.5 +/- 21.0 (n = 39), 69.7 +/- 14.2 (n = 35) and 50.1 +/- 12.2 min (n = 7), respectively. We conclude that, when epidural puncture is performed at upper thoracic levels, toe skin temperature can be a useful monitor to judge the time for additional anaesthetic.

Anesthesia, Epidural↗
PubMed1994

Age-related decrease in toe-thumb temperature difference with lumbar epidural anaesthesia.

With lumbar epidural anaesthesia, big toe skin temperature increases and is associated with a compensatory decrease of thumb temperature. The purpose of the present study was to examine whether thumb-big toe temperature differences were affected by age. Following the attachment of temperature probes at the digital pad of the right big toe and the right thumb, lumbar epidural anaesthesia at L2/3 was performed in 54 patients with 10 ml lidocaine 1.5%. Big toe and thumb skin temperatures were measured continuously and recorded every minute. Fifteen minutes after epidural injection, the toe temperature increased 6.3 +/- 2.1 degrees C (delta F) from the control value, 29.4 +/- 2.2 degrees C, and the thumb temperature decreased -1.5 +/- 1.0 degrees C (delta H) from the control value, 31.6 +/- 2.8 degrees C. Regression coefficient between delta T15 (toe-thumb skin temperature 15 min after epidural injection) and age was: Y = -0.7X + 8.95 (r = 0.35, P < 0.01; Y = delta T15, X = age). The ratio of delta H to delta F and age was expressed as: Y = 0.51X - 46.57 (r = 0.41, P < 0.01: Y = delta H/delta F, X = age). It is concluded that, in lumbar epidural anaesthesia, the decrease of the thumb skin temperature is reduced with aging.

Adult↗
PubMed1994

Arteriovenous differences in PCO2 and cardiac output during CPR in the dog.

Using 14 mongrel dogs, we investigated the correlation between arteriovenous differences of PCO2 (AVD-CO2) and cardiac output (CO) during CPR. Ventricular fibrillation was induced by an electrical current and the respirator was stopped for 5 min. Cardiopulmonary resuscitation (CPR) was performed during the next 10 min and CO was measured with simultaneous arterial and venous blood gas analysis. CO was measured 26 times during CPR. The animals were divided into two groups according to the values of CO during CPR: low-CO group (CO < 0.3 l/min) and high-CO group (CO > or = 0.3 l/min). AVD-CO2 in the low CO group was 39.8 +/- 5.7 mmHg and that of the high group was 27.4 +/- 14.8 mmHg (mean +/- S.D., P < 0.05). In conclusion, AVD-CO2 showed an inverse result with the degree of CO during CPR.

Animals↗
PubMed1994

Milrinone versus glucagon: comparative hemodynamic effects in canine propranolol poisoning.

Glucagon has been reported to be one of the most effective treatments for severe beta-blocker poisoning. Recently, amrinone was suggested as an alternative therapeutic choice for beta-blocker poisoning. Milrinone, a derivative of amrinone, acts independently of beta-adrenoceptors and increases cyclic AMP. Therefore milrinone may also be effective in the treatment of beta-blocker poisoning. In the present study, we compared the effect of glucagon and milrinone in treating severe beta-blocker poisoning. Following the administration of 10 mg/kg propranolol i.v. over 10 min, heart rate, cardiac output, mean arterial pressure, stroke volume, and end tidal CO2 were depressed, while central venous pressure, and pulmonary capillary wedge pressure increased significantly (p < 0.05). Following the administration of saline (Group S, N = 3), glucagon 20 micrograms/kg (Group G, N = 5), and milrinone 300 micrograms/kg (Group M, N = 5), hemodynamic parameters were observed for 30 min. In group M, mean arterial pressure, cardiac output and stroke volume recovered to their baseline values, while central venous pressure and pulmonary capillary wedge pressure decreased. Although there were no significant differences between groups G and M, the heart rate, central venous pressure and pulmonary capillary wedge pressure, mean arterial pressure and stroke volume did not return to baseline values in group G. Milrinone administration produced a significant hemodynamic improvement without increasing the heart rate in the canine model of severe heart failure caused by propranolol. In the glucagon treatment group, central venous pressure and pulmonary capillary wedge pressure improved less than the milrinone group. Although more data are needed before a clinical recommendation, milrinone might be an effective drug to treat beta-blocker poisoning.

Animals↗
PubMed1994

[Fluctuation of injection pressure of syringe pumps; the effect of syringe volumes and speed settings].

We measured fluctuation of injection pressure by several types of commercially available syringe pumps in order to investigate the effect of syringe volumes (Terumo syringe) and speed settings on the irregularity of injection speeds. We recorded the injection pressure continuously with various speed settings, except that one of the pumps injected irregularly at the settings of 2 and 1 ml.h-1. With 50 ml syringes, only two of the six pumps injected precisely at all the speed settings. With the other four types, a steep increase in pressure was recorded at the speed setting of 1 ml.h-1. However irregular infusion was never observed by using a syringe of a high resistant type (TOP syringe). With 30 ml syringes, injection pressures fluctuated in most of the six syringe pumps at a speed lower than 5 ml.h-1. In conclusion, changes in injection pressures depend on types of syringes, syringe volumes and speed settings. We urge not to use a 30 ml syringe to infuse vasoactive drugs with syringe pumps.

Infusion Pumps↗
PubMed1993

End-tidal CO2 and plasma lactate level: a comparison of their use as parameters for evaluating successful CPR.

Serial changes of end-tidal CO2 (ETCO2) and plasma lactate levels during CPR have been described as useful to investigate or evaluate the results of CPR. However, there have been no reports comparing these parameters in the same model. By inducing cardiopulmonary arrest (2-7 min) in 28 Wistar rats, ETCO2 and serum lactate levels were studied after and just before CPR, respectively. In the survived group (N = 16), ETCO2 was maintained in high levels (20.1-16.3 mmHg), however in the non-survived group (N = 12), ETCO2 showed an abrupt decline (6.0-2.0 mmHg). The lactate levels before CPR in two groups were significantly higher than those of control levels, however there was no significant difference just before the CPR between the two groups. ETCO2 during CPR is a useful indicator for determining the successful application of CPR. However, serum lactate levels sampled just before the onset of CPR did not prove to be a useful indicator of successful CPR in rats.

Animals↗