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Biomedical subjects

K Shingu

Publications and source records attributed to K Shingu.

At least 163 records · Page 9Linked to original sources
PubMed1993

[Anesthetic management of an infant with Menkes disease].

Menkes disease is a rare, sex-linked recessive disorder characterized by kinky hair, convulsion, mental retardation, bone and connective tissue lesions, and hypothermia. These symptoms have been attributed to suppression of copper-dependent enzymes resulting from copper deficiency. We report a case of a 7-month-old infant with Menkes disease who underwent repair of inguinal hernia. Anesthesia was maintained with sevoflurane-N2O-O2, and the operation was carried out uneventfully. Although the patient had been medicated with anticonvulsants preoperatively, transient seizure occurred in the recovery room. We also discuss pathophysiology and anesthetic management of a patient with Menkes disease.

Anesthesia, Inhalation↗
PubMed1993

[99mTc-HMPAO SPECT in the brain death--a case report].

Brain single photon emission computed tomography (SPECT) with 99mTc-d,l-hexamethyl-propyleneamine oxime (HMPAO) was performed twice in a 78-year-old man clinically diagnosed as brain death according to the standard criteria of the Japanese Ministry of Welfare. The first brain SPECT demonstrated the tracer accumulation in the brain, indicating preserved cerebral blood flow. The second brain SPECT performed 3 days later revealed cessation of the blood flow. In patients with preserved cerebral blood flow, the diagnosis of brain death cannot be made, even if they meet the existing criteria, because previous report noted the recovery in some of those patients. Brain perfusion SPECT plays an important role as a confirmatory test for the diagnosis of the brain death.

Aged↗
PubMed1993

Clinical evaluation of upper mediastinal dissection for differentiated thyroid carcinoma.

BACKGROUND: An extensive upper mediastinal dissection in advanced differentiated thyroid carcinoma is occasionally required. This investigation was undertaken to clarify the indications for mediastinal lymph node dissection and the route of upper mediastinal metastases. METHODS: Twenty-one patients with differentiated thyroid cancer, who underwent their first radical operations with mediastinal dissection through a partial midline sternotomy, were enrolled in this study. Of 21 patients, 10 (48%) were found to have mediastinal lymph node metastases. RESULTS: The tumor size in the group with metastatic disease was much bigger than that in the group without metastatic disease. Histologic type and age were similar between the two groups. The extent of cervical lymph node metastases was more significant in the group with metastatic disease; in particular, all 10 patients showed more than two metastatic nodes along the internal jugular vein of the tumor-free side. CONCLUSIONS: This study indicates that metastases to the internal jugular chain on the side contralateral to the primary tumor would be an extremely important factor for indication of extensive upper mediastinal lymph node dissection after median partial sternotomy in patients with differentiated thyroid carcinoma.

Adolescent↗
PubMed1992

The divergent actions of volatile anaesthetics on background neuronal activity and reactive capability in the central nervous system in cats.

The effects of halothane, isoflurane, and enflurane on background neuronal activity and reactive capability in the central nervous system were studied in cats. The background neuronal activity was assessed by midbrain reticular cell firing, which was measured by the method of multi-unit activity, and the EEG in the cortex, amygdala, and hippocampus. The reactive capability was assessed by evoked responses in the visual neuronal pathway. All anaesthetics studied suppressed reticular cell firing in a dose-dependent manner, and the suppression by halothane (43.8 +/- 10.3% of control, mean +/- SD) was less than isoflurane (66.5 +/- 5.8%, P < 0.01) and enflurane (73.1 +/- 8.8%, P < 0.05) at 1 MAC. Spontaneous EEG spikes developed at 4.8% isoflurane and 3.6% enflurane anaesthesia. Phasic activation of reticular cell firing was associated with EEG spikes during isoflurane and enflurane anaesthesia, and the activation during enflurane anaesthesia was greater than during isoflurane anaesthesia (P < 0.01). Photic stimulation provoked EEG spikes and repetitive stimulation induced seizure activity only at 3.6% enflurane anaesthesia. Halothane and isoflurane suppressed stimulation induced responses in the visual neuronal pathway. The amplitudes of N1 in visual cortical evoked responses induced by photic stimulation were suppressed to 70.1 +/- 24.5% of control at 2.4% halothane and 39.3 +/- 27.3% at 4.8% isoflurane. Enflurane, at 3.6%, augmented the evoked response induced by photic stimulation (398.4 +/- 83.0% of control in the amplitude of N1). These results indicate that all the agents studied had suppressive actions on background neuronal activity in the order halothane < isoflurane = enflurane. The effects on reactive capability were divergent among agents, e.g., enflurane enhanced, halothane suppressed, and the actions of isoflurane were intermediate. We conclude that the anaesthetic effects on background activity and on reactive capability are divergent and that suppression of reactive capability is a factor in determining the ease of clinical application of the anaesthetics.

Amygdala↗
PubMed1992

Flumazenil does not antagonize halothane, thiamylal or propofol anaesthesia in rats.

We have studied the effects of flumazenil on sleep time and EEG in rats anaesthetized with 1.5% halothane, propofol 20 mg kg-1, thiamylal 30 mg kg-1, or combinations of diazepam 5 mg kg-1 and anaesthetic agents. We also studied the effects of flumazenil 0.3, 3 and 30 mg kg-1 on behaviour and EEG. Flumazenil 0.3 and 3 mg kg-1 alone had no effect on behaviour or EEG, but flumazenil 30 mg kg-1 had depressive effects similar to those of diazepam on behaviour and EEG. Flumazenil 0.3, 3 and 30 mg kg-1 i.v., antagonized the effects of diazepam 10 mg kg-1 i.v. on behaviour and EEG. Flumazenil had no antagonistic effect on sleep time induced by anaesthetic agents, but flumazenil 30 mg kg-1 potentiated propofol-induced anaesthesia. Flumazenil did not affect anaesthesia-induced EEG changes. Diazepam 5 mg kg-1 potentiated anaesthesia. Flumazenil antagonism of diazepam potentiation varied with anaesthetic agent: flumazenil 0.3 mg kg-1 antagonized diazepam action in halothane anaesthesia, but 30 mg kg-1 was required in propofol anaesthesia; this large dose was insufficient in thiamylal anaesthesia.

Anesthesia, Inhalation↗
PubMed1992

Responses of plasma adrenocorticotropic hormone, cortisol, and cytokines during and after upper abdominal surgery.

There is currently accumulating evidence for bidirectional communication between the neuroendocrine and immune systems. Various cytokines have been suggested to be involved in the stimulation of stress hormone secretion during the times of infection and inflammation. To assess the possible involvement and pathophysiologic significance of cytokines in the mechanisms responsible for the perioperative stress response of the hypothalamo-pituitary-adrenal axis, we observed the changes of plasma adrenocorticotropic hormone and cortisol levels together with those of plasma endotoxin and cytokine levels. In patients undergoing pancreatoduodenectomy, perioperative stimulation of adrenocorticotropic hormone and cortisol secretion was accompanied by a significant elevation of plasma cytokine levels. Application of epidural block up to the upper thoracic levels failed to suppress this stress response effectively. In patients undergoing unilateral total hip replacement, the response of plasma hormone levels was smaller and briefer with no significant increase of plasma cytokine levels. Application of epidural block up to the lower thoracic levels suppressed this hormonal response almost completely. In patients undergoing pancreatoduodenectomy, a significant elevation of plasma endotoxin level was followed by a gradual but significant elevation of plasma tumor necrosis factor alpha and interleukin-6 levels. It seems likely that the stimulatory effects of these cytokines on the secretion of adrenocorticotropic hormone and cortisol might be involved in the development of the greater and more prolonged stress response of hypothalamo-pituitary-adrenal axis. Our present study suggests that not only neural input from the surgical wound but also stimulation of cytokine production were responsible for the development of the stress response of the hypothalamo-pituitary-adrenal axis during and after upper abdominal surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗
PubMed1991

Electroencephalographic changes during vital capacity breath induction with halothane.

We investigated the EEG responses in 17 patients during induction of anaesthesia with vital capacity breaths of 4% halothane. The control alpha activity changed to a low voltage, 5-25 muV, fast, 20-28 Hz activity at the time of loss of consciousness at 78 (SD 27) s and typical spindle bursts (20-75 muV, 12-15 Hz) developed at 223 (51) s. All patients remained haemodynamically stable. This sequence of EEG changes was similar to that observed during induction with the conventional method of normal tidal volume breathing and a gradual increase of the inspired concentration of halothane.

Adult↗
PubMed1991

Comparison between sevoflurane and halothane for paediatric ambulatory anaesthesia.

We have compared the rapidity and quality of recovery after sevoflurane anaesthesia with those after halothane anaesthesia. Thirty unpremedicated paediatric outpatients undergoing pulsed-dye laser therapy for port-wine stains were allocated randomly to receive either halothane or sevoflurane anaesthesia. Each group received 60% nitrous oxide and 1.0-1.5 MAC of volatile agent in oxygen for approximately 40 min. Patients receiving sevoflurane exhibited more rapid emergence and a significantly shorter postoperative recovery time compared with those receiving halothane. No major adverse effects were encountered in each group. These results suggest that sevoflurane anaesthesia is preferable to halothane anaesthesia for paediatric ambulatory patients.

Ambulatory Surgical Procedures↗
PubMed1991

[Clinical evaluation of operative procedure for differentiated carcinoma of isthmus of the thyroid].

We studied 19 patients who had undergone operation for differentiated carcinoma of isthmus of the thyroid in Shinshu University Hospital from 1967 to 1986. Regarding the operations, total thyroidectomy was performed in 6 cases, subtotal thyroidectomy in 8 cases, lobectomy in one case and isthmectomy in 4 cases. In 12 cases, lymph node dissection was carried out. Among these 12 cases, 6 cases (50%) had evidence of metastasis. Intraglandular metastasis was found in 3 cases. There were no relationship between tumor size and nodal metastasis. From these results, we do not think that total thyroidectomy is indicated in the case of differentiated carcinoma of isthmus of the thyroid. In conclusion, subtotal thyroidectomy with bilateral modified radical neck dissection is sufficient as the operative procedure for differentiated carcinoma of isthmus of the thyroid.

Adenocarcinoma↗
PubMed1990

The ventilation management during the reconstruction of the tracheo-bronchial tree in adults.

The most important point of anesthetic management during the reconstruction of the tracheo-bronchial tree (TBT) is to secure the airway and to maintain adequate ventilation. We experienced 17 cases of reconstruction of the TBT. Various methods of ventilation were achieved; one-lung ventilation, right middle and lower lobes ventilation, and combinations of these. We used double-lumen tubes, single-lumen tubes with or without blocker, spiral tubes, and intravenous catheters. We selected an appropriate ventilation method suitable for the diverse operative modes and achieved satisfactory managements during operation.

Journal Article↗
PubMed1990

Effects of nitrous oxide on the somatosensory evoked response in cats.

The effect of nitrous oxide on the activity of the somatosensory system was studied in cats with brain electrodes implanted chronically. The electrodes were implanted in the primary somatosensory cortex, cortical somatosensory radiation, medial lemniscus and midbrain reticular formation. Alterations in the excitability of the primary sensory pathway were assessed by the changes of the input to and output from these brain areas: the response in the medial lemniscus to the stimulation of the skin represented the input to the thalamic relay nucleus and the response recorded in the cortical sensory radiation represented the output from the thalamic relay nucleus. The concentrations of nitrous oxide studied were 50% and 75% in oxygen, and the drug effect was concentration-related. The cortical response to peripheral stimulation was suppressed in amplitude by more than 40% of the control with 75% nitrous oxide, and the response in the cortical radiation was suppressed by 20% of the control with the same dose of nitrous oxide. The response in the cortical radiation to stimulation of the medial lemniscus was suppressed by 20% of the control and the postsynaptic component of the cortical response to the stimulation of the medial lemniscus was suppressed by more than 50% of the control. The multi-unit activity of the brainstem reticular formation was enhanced by nitrous oxide in a dose related manner. The excitability of the thalamic relay nucleus and the primary somatosensory cortex was suppressed by natural slow wave sleep when the reticular multi-unit activity was suppressed, and they were enhanced by paradoxical phase of sleep when the reticular multi-unit activity was enhanced. These findings indicated that the degree of suppression of excitability by nitrous oxide is similar in both the thalamic relay nucleus and sensory cortex, and its action on the brain stem reticular formation is different from that on the primary sensory system. The suppression of sensory functions shown in the present study provides a certain clue to the understanding of the neural basis that though nitrous oxide does not produce deep surgical anesthesia, it does induce potent analgesia and sedation during surgery.

Journal Article↗
PubMed1990

Cyclic alteration in the anticonvulsant effect of nitrous oxide in rats.

The anticonvulsant action of nitrous oxide and its time course were studied in rats. Bicuculline, a GABA-receptor antagonist, was administered intravenously at a rate of 0.2 mg.kg(-1).min(-1) during exposure to air (n = 60) or 75% nitrous oxide in oxygen (n = 80). The convulsant dose of bicuculline was determined. The rats were divided into subgroups according to the duration of exposure to air or nitrous oxide, from 0 to 120 min at 15 min intervals. Although the convulsant dose of bicuculline was consistent in the air group (1.03 +/- 0.06 mg.kg(-1), mean +/- SEM), it showed two peaks at 30- and 90 min exposures to nitrous oxide. The threshold dose in the nitrous oxide group was significantly higher than in the air group at only 15- and 30 min exposures (1.50 +/- 0.16, 2.15 +/- 0.25 mg.kg(-1), respectively, P < 0.05). We conclude that nitrous oxide has an anticonvulsant action against bicuculline-induced seizure, and that a cyclic nature exists in its action.

Journal Article↗
PubMed1990

Progressive changes in electroencephalographic responses to nitrous oxide in humans: a possible acute drug tolerance.

The possibility of acute tolerance to nitrous oxide was examined during halothane anesthesia in humans. Nitrous oxide was added to the inspired gas twice. The first admixture induced three successive stages of electroencephalogram (EEG): delta-waves lasting for 13 +/- 12 min, theta-waves lasting for 41 +/- 21 min, and, finally, spindle-type waves. The spindle-type EEG was similar to that of halothane anesthesia in configuration, but smaller in amplitude and faster in frequency than that seen during halothane anesthesia. The second admixture, given after a 20-30-min interval, induced a continuous delta-wave EEG in one patient, theta-waves followed by spindle EEG in eight patients, and spindle-type EEG in four patients. The successive changes of electroencephalographic response during the first admixture indicate that an alteration of central nervous system function occurred. The altered state was maintained in the absence of nitrous oxide: responses to a second admixture were characteristic of the later, altered, stages of responses seen after the first admixture. These findings support the view of acute tolerance to nitrous oxide.

Adult↗
PubMed1990

[Granulocyte beta-adrenoceptor density increased with methylprednisolone in patients receiving dopamine infusion].

Methylprednisolone (MP) is frequently used in shock states, its antishock mechanisms, however, have not been clarified. Effect of MP 10 mg.kg-1 on granulocyte beta-adrenoceptor density was studied in two patients who required dopamine infusion postoperatively. The granulocyte beta-adrenoceptor density was calculated from the binding of [3H] dihydroalprenolol. Arterial blood pressure and cardiac output increased 1 hr after MP administrations. Beta-adrenoceptor densities were low in both cases prior to the administration of MP (16.1 and 24.6 fmol.mg-1 protein), which increased 11 hr after MP (31.2 and 35.8 fmol.mg-1 protein, respectively). The effects of MP to improve status of cardiovascular system in patients receiving catecholamine-infusion may be associated with the increase in the density of myocardial "down-regulated" beta-adrenoceptor.

Dopamine↗
PubMed1990

[Clinical study of propofol in male volunteers].

A clinical phase 1 study of intravenous anesthetic, propofol, was carried out in 6 male volunteers. Propofol, 1, 2, and 2.5 mg.kg-1, was administered intravenously. Anesthetic effects and effects on vital signs, such as blood pressure, heart rate, respiratory rate and body temperature, were investigated. Any adverse effects or abnormal laboratory findings were also investigated. Venous blood samples were obtained frequently for 12 hours to measure blood propofol concentrations. One volunteer out of 6 lost consciousness with 1 mg.kg-1 and the remaining with 2 mg.kg-1 within 1.5 min. In 2 volunteers the duration of anesthesia was inadequate for clinical practice with 2 mg.kg-1. Therefore, 2.5 mg.kg-1 was given. Rhythmic high voltage slow waves appeared immediately after the loss of consciousness in EEG and then basic activity changed to 11 approximately 16 Hz, 30 approximately 60 microV. Blood pressure decreased and heart rate increased but no profound hypotension was observed. Body temperature decreased. No adverse effect, such as laryngospasm, bronchospasm or hiccough, occurred. Laboratory test showed no abnormal result. Pharmacokinetic analysis was carried out using a 3 compartment open model. The half time of distribution phase, 2.6 min, was short, and total clearance, 1.68 l.min-1, was high. We conclude that the proper induction dose of this agent is 2 approximately 2.5 mg.kg-1, which is similar to the values previously reported in European investigations, and that this agent is safe and useful for induction of anesthesia.

Adult↗
PubMed1987

Effects of different speeds of induction with sevoflurane on the EEG in man.

The effects of two kinds of induction speed of sevoflurane anesthesia on the EEG pattern were compared in the same individual using medical student volunteers: a first exposure of 4% was given, followed after full recovery, by incremental doses of 1, 2 and 4% successively, each being administered for 10 min. The arterial blood level of the anesthetic was measured using gaschromatograph. The changes of EEG pattern during fast induction with 4% were not represented by the abbreviation of those observed during the slow induction with the incremental doses. The administration of 4% induced a sudden appearance of high voltage, rhythmic slow waves of 2-3 Hz at 1-3 min when the arterial blood anesthetic level increased maximally, which was then followed by a pattern of faster activities of 10-14 Hz mixed with 5-8 Hz slow waves. In contrast, the administration of incremental doses induced an increase in frequency and amplitude of EEG activities in the light plane, followed by their decreases in deeper planes. The final EEG patterns were identical for both these methods of induction. These findings confirmed our previous hypothesis that not only the arterial blood level of anesthetics but the rate of its increase are important factors determining the EEG pattern of anesthesia

Journal Article↗
PubMed1985

Chiral discrimination of 5,6-epoxy-3-dehydroretinal by aporetinochrome and cattle opsin.

The combination of a racemic all-trans 5,6-epoxy-3-dehydroretinal (EDR) with aporetinochrome formed a mixture of two diastereomeric pigments. One of the diastereomeric pigments which contained the all-trans EDR with a negative circular dichroic (CD) band, hereafter called EDR(-)-chrome, has its visible absorption maximum around 438 nm, while the other pigment, called EDR(+)-chrome, has its maximum at 464 nm. These were substantiated by measuring the optical activities of the two EDR isomers which were extracted from a mixture of racemic all-trans EDR and a smaller amount of aporetinochrome following exposure to orange light (greater than 530 nm) that irradiates EDR(+)-chrome selectively. The extracted all-trans EDR had a negative CD band around 240 nm and the extracted 11-cis EDR had a positive band in that region with two negative bands on either side of the main band. In the case of both pigments, the effect of alkalinization on the increase of absorbance in the near-ultraviolet and the decrease of absorbance in the visible region was proportionate, qualitatively, to that on the positive CD intensities in both regions. These results suggest that the chromophore EDR in each pigment binds to the same binding site via a Schiff base. The EDR(+)-chrome exhibited properties similar to those of retinochrome, but EDR(-)-chrome showed some different properties, i.e. its formation rate was slower than that of the former one and its absorption band in the near-ultraviolet appeared even at neutral pH. Moreover, by exposing EDR(-)-chrome to yellow light (greater than 480 nm), only a part of its prosthetic all-trans EDR was isomerized and resulted in the formation of 11-cis and 13-cis isomers. This variation in photoisomerizing activity was supposed to be due to the difference in conformation of the side chain between EDR(+) and EDR(-) in aporetinochrome. Combination of 11-cis EDR with cattle opsin was also shown to result in the formation of two diastereomeric pigments. The absorption maxima of the diastereomers containing 11-cis EDR(+) and EDR(-) were at about 446 and 474 nm, respectively.

Animals↗