Biomedical subjects

T Shiga

Publications and source records attributed to T Shiga.

At least 19 recordsLinked to original sources

PubMed2006

Effect of prophylactic bronchodilator treatment with i.v. carperitide on airway resistance and lung compliance after tracheal intubation.

BACKGROUND: Lung resistance increases after induction of anaesthesia. We hypothesized that prophylactic bronchodilation with i.v. carperitide before tracheal intubation would decrease airway resistance and increase lung compliance after placement of the tracheal tube in both smokers and nonsmokers. METHODS: Ninety-seven adults aged between 24 and 59 yr were randomized to receive i.v. normal saline (0.9% saline) (control) or carperitide, 0.2 microg kg(-1) min(-1) throughout the study. The 97 patients included smokers and nonsmokers. Thus the patients were allocated to one of the four groups: smokers who received normal saline (n=21), nonsmokers who received normal saline (n=27), smokers who received carperitide (n=19) or nonsmokers who received carperitide (n=30). Thirty minutes after starting normal saline or carperitide infusion, we administered thiamylal 5 mg kg(-1) and fentanyl 5 microg kg(-1) to induce general anaesthesia and vecuronium 0.3 mg kg(-1) for muscle relaxation. Continuous infusion of thiamylal 15 mg kg(-1) h(-1) followed anaesthetic induction. Mean airway resistance (R(awm)), expiratory airway resistance (R(awe)) and dynamic lung compliance (C(dyn)) were determined 4, 8, 12 and 16 min after tracheal intubation and compared between the four groups. RESULTS: At 4 min after intubation, R(awm) and R(awe) were higher and C(dyn) lower in smokers than in nonsmokers in the control group. R(awm) and R(awe) were lower and C(dyn) higher in smokers in the carperitide group than in smokers in the control group. R(awm) and R(awe) were lower in nonsmokers in the carperitide group than in nonsmokers in the control group. CONCLUSIONS: Marked bronchoconstriction occurred in the control groups (smokers and nonsmokers) 4 min after tracheal intubation. Prophylactic treatment with carperitide before induction of anaesthesia and tracheal intubation was advantageous, particularly in smokers.

Adult↗

PubMed2006

Within-day variability of whole-body and segmental bioelectrical impedance in a standing position.

OBJECTIVE: To assess the variation in whole-body and segmental bioelectrical impedance measured in the standing position over the course of a day. SUBJECTS: Sixteen healthy men aged 29.6 +/- 3.1 years participated in this study. MEASUREMENT: Impedance between the hands (Z H-H), the feet (Z F-F), and the both hands and feet (Z H-F) was measured using a bioelectrical impedance analysis (BIA) data acquisition system at 500 microA and 50 kHz. Body weight, Z H-H, Z F-F and Z H-F were measured every 3 h from 0900 to 1800. RESULTS: Body weight was slightly, but significantly, changed at 1200 (-0.4 +/- 0.4 kg, P < 0.05), 1500 (+0.4 +/- 0.3 kg, P < 0.05) and 1800 (-0.2 +/- 0.2 kg, P < 0.05) compared to their respective previous measurement values. Z H-H significantly increased (P < 0.05) and Z F-F significantly decreased (P < 0.05) over the course of a day. The mean changes in impedance from 0900 to 1800 were +27.2 Omega (Z H-H) and -31.8 Omega (Z F-F), respectively. There were no changes in Z H-H at 1500 and in Z F-F at 1800 compared to their respective previous measurement values. The Z H-F value did not change significantly between 0900 and 1800. CONCLUSION: Although changes in standing whole-body impedance during the day are small, arm and leg segmental impedance measurements change significantly. Therefore, it is necessary to measure the impedance at regularly scheduled times when evaluating whole-body %fat or body water content using the segmental BIA method.

Adult↗

PubMed2005

Selective serotonin reuptake inhibitor treatment of early postnatal mice reverses their prenatal stress-induced brain dysfunction.

Prenatal stress has long-lasting effects on cognitive function and on the hypothalamic-pituitary-adrenal response to stress. We previously reported that the serotonin concentration and synaptic density in the hippocampus were reduced following prenatal stress [Int J Dev Neurosci 16 (1998) 209]. Since serotonin plays a role in the formation and maintenance of synapses, we hypothesized that a neonatal reduction in hippocampal serotonin levels may lead to learning disabilities in prenatally stressed mice. To test this hypothesis, we treated prenatally stressed mice with a selective serotonin reuptake inhibitor in order to normalize their postnatal serotonin turnover levels. What we found was that the oral administration of a selective serotonin reuptake inhibitor to prenatally stressed mice during postnatal weeks 1-3 but not 6-8 normalized their corticosterone response to stress, serotonin turnover in the hippocampus, and density of dendritic spines and synapses in the hippocampal CA3 region. Concomitantly, such treatment partially restored their ability to learn spatial information.

Age Factors↗

PubMed2003

Propofol alone, sevoflurane alone, and combined propofol-sevoflurane anaesthesia in electroconvulsive therapy.

Electroconvulsive therapy is an effective treatment for severe and medication-resistant depression. There have been no reports describing how a volatile anaesthetic affects haemodynamic responses, seizure duration, and recovery characteristics during electroconvulsive therapy. We carried out a repeated-measure crossover study to compare the effects on haemodynamic responses, seizure duration, and recovery characteristics of the following types of anaesthesia in electroconvulsive therapy: propofol alone, sevoflurane alone, and propofol combined with sevoflurane. We recruited 50 patients requiring electroconvulsive therapy for depression. For anaesthesia induction, 1.5 mg/kg propofol (condition P), 5% sevoflurane in oxygen following a vital capacity rapid inhalation induction (condition S), or 1.5 mg/kg propofol followed by 5% sevoflurane in oxygen (condition PS) was administered. Succinylcholine 1.5 mg/kg was then given. Electrical stimulation was administered after fasciculation. Measurements were obtained before anaesthesia induction (baseline), prior to succinylcholine administration, prior to electroconvulsive therapy, and at the peak after electroconvulsive therapy. After electroconvulsive therapy, peak heart rate and peak mean arterial pressure were highest in condition S. Whereas recovery time was longest in condition PS, motor seizure duration was significantly shorter than in either condition P or S. Electroencephalographic seizure duration was significantly shorter in condition PS than in condition P and significantly shorter in condition S than in condition P. Sevoflurane anaesthesia alone is most disadvantageous in terms of haemodynamics. Propofol-sevoflurane anaesthesia is advantageous in terms of haemodynamics, but disadvantageous in terms of seizure duration and recovery time. Propofol alone is most advantageous in terms of seizure duration.

Adult↗

PubMed2002

The effects of intravenous lignocaine on haemodynamics and seizure duration during electroconvulsive therapy.

Electroconvulsive therapy (ECT) is commonly associated with acute hyperdynamic cardiovascular responses, and we hypothesize that intravenous lignocaine can blunt this response. We have measured the effect of lignocaine 1.5 mg/kg i.v. on heart rate and mean arterial pressure during electroconvulsive therapy. Furthermore, we also assessed seizure duration using both the cuff method and two-lead electroencephalography. We studied 25 patients using a randomized, double-blind, placebo-controlled crossover study design. Patients in the control group were given intravenous saline 0.075 ml/kg, and those in the lignocaine group were given intravenous lignocaine 2% 1.5 mg/kg, and this treatment was conducted one minute before intravenous propofol 1.5 mg/kg to induce unconsciousness. Succinylcholine 1.5 mg/kg was then administered intravenously and electrical stimulation was administered after fasciculation. Measurements were taken at the baseline, prior to succinycholine, prior to electroconvulsive therapy and at the peak response after electroconvulsive therapy. Intravenous lignocaine significantly reduced the increases in heart rate after electroconvulsive therapy, as compared with the placebo. The use of intravenous lignocaine was, however, associated with a remarkably shortened seizure duration. Due to the reduction in seizure duration, routine administration of intravenous lignocaine may not be advisable since it may interfere with the psychotherapeutic efficacy of electroconvulsive therapy. However, intravenous lignocaine medication for electroconvulsive therapy is potentially useful for reducing tachycardia in high-risk patients and reducing the severity of propofol injection pain in comparison with a placebo.

Adult↗

PubMed2001

Interaction of Myc-associated zinc finger protein with DCC, the product of a tumor-suppressor gene, during the neural differentiation of P19 EC cells.

Expression of the DCC (deleted in colorectal cancer) protein is strongly induced during the neural differentiation of mouse P19 embryonal carcinoma (EC) cells that occurs when these cells are treated with retinoic acid (RA). Myc-associated zinc finger protein (MAZ) is a DNA-binding protein that is widely expressed and functions in human, mouse and hamster cells as an activator, an initiator or a terminator of transcription. However, the biological functions of MAZ remain elusive. We report here that MAZ associates with the cytoplasmic domain of the DCC protein in vivo and in vitro. Yeast two-hybrid assays confirmed this association. An immunofluorescence study demonstrated that DCC protein is expressed at elevated levels in neuron-like P19 EC cells, in particular in axons, in which the MAZ protein is also expressed. We found that MAZ was translocated from the nucleus to the cytoplasm during the RA-induced terminal differentiation of P19 EC cells with resultant loss of the ability of MAZ to bind to the ME1a1 site of the c-myc promoter. Taken together, our observations imply that the DCC protein might play a critical role as a signaling molecule in the regulation of the transcriptional activity of MAZ during the neural differentiation of P19 EC cells.

Active Transport, Cell Nucleus↗

PubMed2001

Abnormal neuronal network in anorexia nervosa studied with I-123-IMP SPECT.

Single photon emission computed tomography was used to study 14 female patients with anorexia nervosa and 8 female normal comparison subjects. Automatic voxel-based analysis of the images was carried out using statistical parametric mapping (SPM) software. Statistics across the entire brain were displayed as Z scores (threshold: P<0.05). Compared with the normal comparison subjects, the anorectic patients were characterized by hypoperfusion in the medial prefrontal cortex and the anterior cingulate gyrus, and hyperperfusion in the thalamus and the amygdala-hippocampus complex. These results suggest that a dysfunction in neuronal circuitry may be related to anorexia nervosa.

Adolescent↗

PubMed2001

Serotonin 2A receptor-like immunoreactivity is detected in astrocytes but not in oligodendrocytes of rat spinal cord.

The distribution of the serotonin 2A (5-HT2A) receptor in glial cells in the white matter of rat spinal cord was immunohistochemically examined with specific antibodies against the 5-HT2A receptor. 5-HT2A receptor-like immunoreactivity was detected in astrocytes that were identified by an antibody against the glial fibrillary acidic protein. In contrast, 5-HT2A receptor-like immunoreactivity was not observed in oligodendrocytes.

Animals↗

PubMed2001

Time-sequential changes in biomechanical and morphological properties of articular cartilage in cryopreserved osteochondral allografting.

This study examined time-sequential changes in the biomechanical and morphological properties of articular cartilage that had received cryopreserved osteochondral allografting. Osteochondral blocks obtained from the femurs of 18 rabbits were cryopreserved with dimethylsulfoxide (DMSO), using a two-step freezing method, and allografted to the femurs of another 18 rabbits. Specimens for biomechanical and morphological examinations were prepared at the second, fourth, and twelfth weeks after allografting (n = 18). In 12 allografted rabbits, biomechanical features were examined with an indentation test apparatus, and histological changes were studied with a light microscope (second week, n = 4; fourth week, n = 4; twelfth week, n = 4). In the other 6 allografted rabbits, cartilage surfaces were studied with a scanning electron microscope (second week, n = 2; fourth week, n = 2; twelfth week, n = 2). For controls, fresh, DMSO-treated, or DMSO-treated + cryopreserved specimens were examined biomechanically and morphologically. In the time-sequential examination of biomechanical features, both the parameter for elasticity (i.e., ratio of instant elastic strain to maximum strain) and the parameter for viscosity (i.e., average retardation time) significantly changed. Light microscopy showed chronological decreases in safranin-O staining intensity in the matrix, and progression of degeneration. On scanning electron microscopy, disruption of the cartilage surface was also recognized. Therefore, changes in biomechanical properties due to cryopreservation could cause irreversible changes in the cartilage in cryopreserved osteochondral allografting.

Animals↗

PubMed2001

Perinuclear-antineutrophil cytoplasmic antibodies are associated with vasculitis.

We describe a 62-year-old man with perinuclear-antineutrophil cytoplasmic antibodies-associated vasculitis, which involved the heart, lung, and kidneys. The patient's care was complicated by total occlusions of the brachiocephalic and right renal arteries and a stenosis of the left renal artery. Involvement of large-sized vessels has not been reported in patients with perinuclear-antineutrophil cytoplasmic antibodies-associated vasculitis.

Antibodies, Antineutrophil Cytoplasmic↗

PubMed2001

Immunohistochemical demonstration of nerve fibers in the synovial fold of the human cervical facet joint.

The role of the intra-articular synovial fold as a source of facet joint pain is unclear, because the nature of nociceptive innervation in lumbar synovial folds is controversial, and there have been no such studies in cervical synovial folds. The present study aimed to demonstrate the presence of nerve fibers including nociceptive fibers in synovial folds of human cervical facet joints using immunohistochemistry. Synovial folds of cervical facet joints removed from patients undergoing cervical spine laminoplasty were analyzed immunohistochemically using antibodies to protein gene product 9.5, beta III-tubulin, substance P and calcitonin gene-related peptide. Many nerve fibers immunoreactive for protein gene product 9.5 and beta III-tubulin were demonstrated both around blood vessels and as free fibers in the stroma of the synovial fold. Also. immunostaining showed the presence of free nerve fibers immunoreactive for substance P and calcitonin gene-related peptide in the stroma. The presence of putative nociceptive fibers in cervical synovial folds supports a possible role for these structures as a source of cervical facet joint pain.

Adult↗

PubMed2001

Reverse use-dependent QT prolongation during infusion of nifekalant in a case of recurrent ventricular tachycardia with old myocardial infarction.

Pure class III antiarrhythmic agents cause reverse use-dependent QT prolongation. Nifekalant is a new class III antiarrhythmic agent and blocks rapid component of the delayed rectifier K+ current (Ikr) selectively. To prevent recurrent ventricular tachycardia in a patient with old myocardial infarction, nifekalant was administered by continuous intravenous infusion. There was little variation in the blood level of nifekalant during the 1-day period, but the QTc interval became shorter with an increase of the heart rate early in the morning. It is therefore considered advisable to monitor the heart rate and QTc interval during administration of nifekalant by continuous intravenous infusion.

Anti-Arrhythmia Agents↗

PubMed2001

Electrophysiological characteristic of a patient exhibiting the short-coupled variant of torsade de pointes.

A 41-year-old man was admitted because of syncope. The electrocardiogram showed torsade de pointes (Tdp) with no long QT interval and the coupling interval of the initial beat of Tdp was 240 ms. Heterogeneity of ventricular refractoriness was observed together with shortness of the effective refractory period measured at the right ventricular inflow site where the paced QRS morphology was the same as that of the initial beat of Tdp. Verapamil could suppress frequent ventricular premature complexes with a short coupling interval, which lead to Tdp. Polymorphic ventricular tachycardia was induced by triple ventricular extrastimuli. A pure potassium channel blocker was successful in inhibiting polymorphic ventricular tachycardia inducibility by prolongation of refractoriness. These results suggested that triggered ventricular premature complexes may be represent the initiating mechanism, whereas the shortness of local refractory period and heterogeneity of ventricular refractoriness may play a role in the development and the maintenance of the Tdp.

Adult↗

PubMed2001

The effects of diltiazem on hemodynamics and seizure duration during electroconvulsive therapy.

UNLABELLED: Electroconvulsive therapy (ECT) is often associated with acute hyperdynamic responses, and we hypothesize that diltiazem can blunt this response. We measured the effect of a 10-mg dose of diltiazem on heart rate and mean arterial pressure during ECT. Furthermore, we assessed seizure duration by using both the cuff method and two-lead electroencephalogram. We studied 18 patients with a randomized, double-blinded, placebo-controlled cross-over study design. Diltiazem significantly reduced heart rate and mean arterial pressure just after medication, and it also significantly reduced the increases in these variables after ECT, as compared with the placebo. The use of diltiazem was, however, associated with a shortened seizure duration, possibly making ECT less effective. Because of the reduction in seizure duration, the routine administration of diltiazem may not be advisable because it can possibly interfere with the psychotherapeutic efficacy of ECT. However, diltiazem medication for ECT is potentially useful for reducing tachycardia and hypertension in high-risk patients. IMPLICATIONS: Diltiazem can blunt acute hyperdynamic responses after electroconvulsive therapy, but seizure duration is also significantly reduced, possibly making this therapy less effective.

Adult↗

PubMed2001

Clinical advantages of interictal SPECT coregistered to magnetic resonance imaging in patients with epilepsy.

PURPOSE: The aim of this study was to investigate the clinical value of coregistration of interictal SPECT and magnetic resonance imaging (MRI) in patients with partial epilepsy. MATERIALS AND METHODS: Seventeen patients with partial epilepsy were examined with I-123 IMP or Tc-99m ethyl cysteinate dimer SPECT during the interictal phase. The SPECT images were automatically coregistered to axial T1 weighted MRIs. Asymmetry indexes (AIs) were calculated in both nonregistered images and coregistered images. RESULTS: SPECT images showed areas of decreased tracer uptake in 12 patients. In two patients, the relation between the tumor and the extent of decreased uptake became more accurate in the coregistered images. In five cases, the coregistered images clearly showed that the decreased uptake was located in the sulcus. The AIs were significantly reduced from 14.29 +/- 7.23 to 5.86 +/- 3.48 (P < 0.001) after the images were coregistered in these cases. In five cases, the coregistered images indicated that the decreased areas were in agreement with the cortical findings. No significant differences in the AIs were observed in these cases (16.50 +/- 6.19 versus 17.83 +/- 4.45). Thus, the coregistered images were useful not only to differentiate actual hypoperfusion from artificial hypoperfusion resulting from partial volume effects but also to improve the accuracy of AIs. CONCLUSION: The coregistration of interictal perfusion SPECT and MRI is useful not only to provide precise functional and anatomic mapping but also to improve the accuracy of calculations of the semiquantitative analysis of regional cerebral blood flow parameters during the interictal state of epilepsy.

Adolescent↗

PubMed2001

Thalamic asymmetry on interictal SPECT in patients with frontal lobe epilepsy.

BACKGROUND: Interictal brain single photon emission computed tomography (SPECT) is useful for the detection of seizure focus. Recent reports indicate a hypoperfusion in the ipsilateral thalamus as a seizure focus on interictal SPECT in temporal lobe epilepsy. In frontal lobe epilepsy (FLE), however, the alteration of perfusion in the thalamus has not been well documented. This study aimed to assess whether perfusion analysis on the thalamus may add useful information for the detection of epileptic foci in patients with FLE. METHODS: Interictal brain SPECT was performed in 11 patients with FLE. The asymmetry index for the thalamus and frontal area in the SPECT image was calculated in order to compare the laterality of the seizure foci. RESULTS: Thalamic asymmetry was seen in seven patients (64%), while cortial asymmetry was seen in six patients (55%). The concordance with the lateralization of the seizure foci was 6/7 (86%) in the thalamus, and 4/6 (67%) in the frontal area. Four patients showed only thalamic asymmetry. Concordance with the lateralization of the seizure focus was found in all of them. CONCLUSION: These preliminary results suggest that hypoperfusion in the thalamus may have a complementary role to lateralize the epileptic foci in patients with FLE.

Adolescent↗

PubMed2001

Role of desethylamiodarone in the anticoagulant effect of concurrent amiodarone and warfarin therapy.

BACKGROUND: The concurrent use of amiodarone and warfarin inhibits metabolism of S-warfarinby cytochrome P450 (CYP) 2C9, thereby increasing the anticoagulant effect of warfarin. Amiodarone primarily inhibits CYP1A2 and CYP3A4, and desethylamiodarone primarily inhibits CYP2C9. We investigate whether a relationship exists between the plasma concentration of desethylamiodarone and anticoagulation when amiodarone is administered to patients receiving warfarin therapy. METHODS AND RESULTS: The correlation between the plasma concentration of either amiodarone or desethylamiodarone, and prolongation of prothrombin time-international normalized ratio/dose of warfarin (Delta INR/Dose) on day 7 of amiodarone administration was studied in 25 patients (22-74 years old) with structural heart disease and refractory arrhythmias receiving stable warfarin therapy. RESULTS: No correlation was found between the plasma concentration of amiodarone and Delta INR/Dose, but a correlation was found between the plasma concentration of desethylamiodarone and Delta INR/Dose. CONCLUSIONS: It was suggested that inhibition of CYP2C9 by desethylamiodarone, the active metabolite of amiodarone, plays an important role in the interaction of warfarin and amiodarone.

Adult↗

PubMed2001

Amiodarone-Induced thyroid dysfunction and ventricular tachyarrhythmias during long-term therapy in Japan.

In 232 Japanese patients receiving long-term amiodarone therapy for life-threatening ventricular tachyarrhythmias, hyperthyroidism and hypothyroidism developed in 29 patients (12.5%) and 25 patients (10.8%), respectively. In patients with hyperthyroidism, the recurrence of sustained ventricular tachycardia was significantly higher with thyrotoxicosis than in the euthyroid period (31% vs 3%, p<0.01). Holter monitoring showed that the average heart rate and ventricular premature complexes significantly increased with hyperthyroidism. On the other hand, there was no increase in the recurrence of ventricular tachyarrhythmia with hypothyroidism. There was no change in the dose or the plasma concentration of amiodarone or desethylamiodarone in the euthyroid period or when hyperthyroidism or hypothyroidism manifested. It is important to monitor for arrhythmia when hyperthyroidism develops during amiodarone therapy.

Adult↗