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Biomedical subjects

K Fukumitsu

Publications and source records attributed to K Fukumitsu.

At least 55 records · Page 3Linked to original sources
PubMed1993

[Respiratory outcome in extremely premature infants following general anesthesia].

This study was aimed to predict the need of postoperative tracheal intubation in premature infants following anesthesia using volatile anesthetics by means of the scoring system derived from our former study of ketamine anesthesia. The subjects consisted of 14 infants (birth weight: 719 +/- 130 g and weight at operation 1882 +/- 312 g) needing cryotherapy for retinopathy and anesthetized with less than 1 MAC of volatile anesthetics. Respiratory outcome was successfully predicted in 9 patients (64%) while no infant was predicted incorrectly to be ready for tracheal extubation. The incidences of postoperative ventilatory support were 28% and 32% after anesthesia with volatile anesthetics and ketamine anesthesia, respectively. However, general anesthesia with volatile anesthetics appeared to be superior in actual outcome to ketamine anesthesia among the patients with high risk scores.

Anesthesia, General↗
PubMed1993

[The anesthetic management of cesarean section for multiple pregnant patients].

Anesthetic management of cesarean section for twenty multiple pregnant patients, who were pregnant with triplet or quadruplet, was compared with that for 325 single pregnant patients and 21 twin pregnant patients. For anesthetic methods, spinal anesthesia was chosen most frequently in the multiple pregnant patients, as in single and twin (more than 75 percent). In multiple pregnant patients, the incidence of emergency operation was less. In multiple pregnant patients who received spinal anesthesia, gestational age was lower; birth weight was lighter; length of fundus uteri was longer; and blood loss including amniotic fluid was larger. In triplets, the third infants' UID-time was prolonged and their Apgar score was lower.

Anesthesia, Epidural↗
PubMed1992

Duration of apnea in anesthetized infants and children required for desaturation of hemoglobin to 95%. The influence of upper respiratory infection.

Sixty-one patients ASA physical status 1-2 aged 1 month to 12 years undergoing elective surgery were included in the study. Anesthesia was induced via a mask with sevoflurane up to 5% and 66% nitrous oxide in oxygen. After paralysis with vecuronium (0.12 mg/kg iv), the trachea was intubated and the lungs were ventilated manually with 3% sevoflurane in oxygen until the end-tidal nitrous oxide decreased to less than 5%. Apnea was started by disconnecting the breathing circuit from the endotracheal tube. The time from the start of apnea to Spo2 of 95% was measured. Manual ventilation was reinstituted when Spo2 decreased to 95% and another set of vital signs was recorded. Twenty of 61 patients had symptoms of upper respiratory infection. The time to Spo2 of 95% correlated well with height, age, and body weight both by linear and non-linear regression analyses. The patients with symptomatic upper respiratory infection required less time for Spo2 to decrease to 95% compared to the asymptomatic children. We conclude that younger children require less time for Spo2 to decrease to 95%. The presence of upper respiratory infection is an additional factor increasing the susceptibility of small children to hypoxemia.

Anesthesia, Inhalation↗
PubMed1991

Pentazocine-induced catecholamine efflux from the dog perfused adrenals.

This study has been undertaken to determine whether pentazocine induces catecholamine efflux from the adrenal medulla as a mechanism for its sympathomimetic effect. Dog isolated adrenals were perfused retrogradely with modified Locke's solution. The efflux of catecholamines from dog perfused adrenals was increased from the resting output of 0.18 +/- 0.04 micrograms min-1 (mean +/- s.e.), to 0.47 +/- 0.13 micrograms min-1 by the administration of pentazocine (50 microM). The pentazocine-induced catecholamine efflux was dose-dependent in the 50-400 microM dose range. This effect of pentazocine was not inhibited by either a combination of atropine and (+)-tubocurarine, or verapamil, in contrast to acetylcholine-induced catecholamine release. There was no significant difference in potency among stereoisomers, i.e. (+)-, (-)- and (+/-)-pentazocine, in inducing catecholamine efflux. Naloxone did not influence the effects of either (+)- or (-)-pentazocine. The interaction of pentazocine with acetylcholine-induced catecholamine release was also examined. Both (+)- and (-)-pentazocine inhibited acetylcholine-induced catecholamine release dose-dependently, and these inhibitory effects were not reversed by naloxone. Acetylcholine-induced catecholamine release was accompanied by increased dopamine-beta-hydroxylase release, whereas pentazocine-induced catecholamine efflux was not. These results suggest that pentazocine directly acts on the adrenal medulla to induce catecholamine efflux via a non-exocytotic mechanism, and that opioid receptors do not play a role in this action.

Acetylcholine↗
PubMed1991

Roles of beta 1- and beta 2-adrenoceptors in the mechanism of halothane myocardial sensitization in dogs.

The authors investigated the comparative roles of beta 1- and beta 2-adrenoceptors in myocardial sensitization by halothane in dogs. The arrhythmogenic dose (AD) of isoproterenol was determined in the presence of various doses of phenylephrine during halothane anesthesia in dogs, and the influences of 1-metoprolol (beta 1-antagonist) and ICI-118,551 (beta 2-antagonist) on the AD were examined. In the presence of 1-metoprolol, the AD of isoproterenol was significantly greater than the control, but in the presence of ICI-118,551, the AD of isoproterenol was lower. Blood pressure during the arrhythmias was higher in the presence of ICI-118,551 than that in controls. In addition, the AD of ritodrine (beta 2-agonist) was also determined at various doses of phenylephrine. The interaction between phenylephrine and ritodrine in inducing arrhythmias showed hyperbolic isoboles. However, 1-metoprolol completely inhibited the occurrence of arrhythmias induced by ritodrine and phenylephrine. The results suggest that myocardial beta 1-adrenoceptors play an essential role in the genesis of arrhythmias during halothane anesthesia in dogs, whereas beta 2-adrenoceptors do not.

Adrenergic beta-Agonists↗
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

Effects of pentazocine and other opioids on the potassium-evoked release of [3H]noradrenaline from guinea pig cortical slices.

Noradrenaline release and its modulation via presynaptic opioid receptors were examined in guinea pig cortical slices. Slices preloaded with [3H]noradrenaline were superfused in the presence of desipramine (1 microM) and were stimulated by 16 mM K+. 1-Pentazocine inhibited the K+-evoked release of [3H]noradrenaline in a dose-dependent manner (3 x 10(-7)-10(-5) M), while d-pentazocine did not inhibit. This inhibitory effect of 1-pentazocine was antagonized by Mr 2266 (10(-6) M) but not by naloxone (10(-6) M). Among other opioids, dynorphin A-(1-13) and ethylketocyclazocine (kappa agonists) decreased the K+-evoked release of [3H]noradrenaline. Tyr-D-Ala-Gly-NMe-Phe-Gly-ol (DAGO, mu agonist) also inhibited [3H]noradrenaline release but was less potent than the kappa agonists. [D-Pen2,D-Pen5]enkephalin (DPDPE, delta agonist) and phencyclidine (sigma agonist) had no effects on the stimulated release of [3H]noradrenaline. Thus, it was shown that kappa receptors are the major subtype of opioid receptor involved in modulation of noradrenaline release in guinea pig cortex, and that 1-pentazocine inhibits the K+-evoked release of noradrenaline through activation of these receptors.

Animals↗
PubMed1989

Comparison of recorded values from six pulse oximeters.

Recorded values (SpO2) of oxygen saturation from six noninvasive pulse oximeters were compared to each other and to the value from a cooximeter. Simultaneous measurements were obtained from each instrument in eight healthy nonsmoking volunteers rendered hypoxic greater than 70% SpO2. Functional arterial oxygen saturation (SaO2), fractional SaO2 (%HbO2), and percent fraction of carboxyhemoglobin (HbCO) and methemoglobin (MetHb) were determined by a cooximeter. The difference between SaO2 and %HbO2 was 2.3 +/- 0.3 (SD) % (p less than .001) with 1.4 +/- 0.1% HbCO and 0.9 +/- 0.1% MetHb. The SpO2 values in two instruments were close to %HbO2, while the other instruments correlated approximately with SaO2. The greatest SpO2 difference among the instruments was 2.7 +/- 1.9% (p less than .001). These results may indicate that, under normal dyshemoglobin levels, some pulse oximeters are calibrated to estimate SaO2 and others to estimate %HbO2. Since the pulse oximeter using two wavelengths cannot measure accurately %HbO2 or SaO2 in the presence of dyshemoglobin, SpO2 values would be independent from %HbO2 and SaO2. A standard calibration method for pulse oximeters should be established by the manufacturers.

Adult↗
PubMed1989

Effects of d- and l-pentazocine on the release and uptake of norepinephrine in rat brain cortex.

Effects of d- and l-pentazocine on the release and uptake of norepinephrine and other neurotransmitters were examined in rat cerebral cortex. D- and l-pentazocine (10(-6)-10(-4) M) evoked the release of tritium from rat cortex slices preloaded with [3H]norepinephrine. Both isomers of pentazocine (3 x 10(-5) M) also evoked the release of tritium from slices preloaded with [3H]dopamine and [3H]5-hydroxytryptamine ([3H]5-HT) but did not from those preloaded with [3H] gamma-aminobutyric acid ([3H]GABA) and [3H]choline. The releasing effect of pentazocine was neither dependent on the extracellular calcium nor antagonized by naloxone. Both isomers inhibited the uptake of [3H]norepinephrine, [3H]dopamine and [3H]5-HT but not that of [3H]GABA and [3H]choline into synaptosomes prepared from the cortex. These results suggest that the effects of d- and l-pentazocine on release and uptake are relatively specific to monoamines and might explain some aspects of pharmacological actions of pentazocine.

Animals↗
PubMed1988

Effects of carboxyhemoglobin on pulse oximetry in humans.

Carboxyhemoglobin (HbCO)-induced reading errors of the Biox 3700 (version J, Ohmeda) pulse oximeter were determined in 6 healthy volunteers rendered hypoxic (Sa(O)(2) from 65-100%) by breathing mixtures of air in nitrogen. The oximeter reading (Sp(O)(2)) before and after cigarette smoking was compared with oxyhemoglobin percentage (%HbO(2)). Mean HbCO levels were; 3.0 +/- 1.0 (SD) % before cigarette smoking and 5.2 +/- 1.7% after smoking, whereas mean methemoglobin was unchanged as 0.5 +/- 0.1%. The correlations of the Sp(O)(2) (y) with %HbO(2) (x) were; y = 1.01x - 0.30 (r = 0.990, n = 21, P < 0.001) when %HbCO was less than 2.5, and y = 1.01x + + 3.21 (r = 0.964, n = 33, P < 0.001) when %HbCO was above 5.0%. The reading error, (Sp(O)(2) - %HbO(2)), could be expressed as a function of %HbCO; 1.06 x %HbCO(2) - 2.49 (r = 0.669, n = 83, P < 0.05). Thus, the Sp(O)(2) is approximately the sum of %HbCO(2) and (%HbCO - 2.5), and overestimates %HbO(2) in the high levels of HbCO. The pulse oximeter should be used with caution in patients with the elevated level of %HbCO.

Journal Article↗
PubMed1987

Selective inhibition by dantrolene of caffeine-induced catecholamine release from perfused dog adrenals.

Effects of dantrolene sodium on catecholamine (CA) release from the perfused dog adrenal medulla was investigated in relation to it's therapeutic action on malignant hyperthermia (MH), in which CAs would play a significant pathophysiological role. Acetylcholine (ACh)-induced CA release was not affected, whereas caffeine-induced CA release was inhibited by dantrolene in a dose-dependent manner (84% inhibition at 10 microM). Dantrolene had no effect on the CA release induced by lasalocid or Na+ deprivation. On the other hand halothane inhibited ACh-induced CA release markedly, Na+ deprivation-induced CA release slightly, but not caffeine-induced CA release at all. The results indicate that dantrolene selectively inhibit caffeine-induced CA release, and that the therapeutic action of dantrolene on MH would be, at least in part, due to inhibition of abnormal release of Ca2+ in the adrenal medullary cells.

Adrenal Glands↗
PubMed1986

Stereospecific effects of d- and l-pentazocine on contractions of the mouse vas deferens.

The effects of the d- and l-isomers of pentazocine were compared to that of racemic pentazocine on contractions of the mouse isolated vas deferens. L-pentazocine inhibited electrically evoked contractions of the mouse vas deferens (MVD) in a dose-dependent manner (ID50 0.37 +/- 0.04 microM). In contrast, d-pentazocine augmented field stimulated contractions dose-dependently; per cent increases in contractions at 10 and 30 microM were 57.8 +/- 18.0 and 98.0 +/- 15.1%, respectively. Racemic pentazocine produced an intermediate effect between the two isomers. The effect of 1-pentazocine was antagonized by naloxone, whereas that of d-pentazocine was not. L-pentazocine did not effect the response of the MVD to exogenous norepinephrine at any concentration tested, while d-pentazocine depressed the response of the MVD to exogenous norepinephrine at one dose (0.3 microM). These findings demonstrate that d- and l-pentazocine produce opposite effects on the MVD. The effects of l-pentazocine are opioid mediated, while those of d-pentazocine are not. In the racemic mixture the opposing effects of the two isomers modulate each other, resulting in a diminished effect.

Animals↗