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M Kawamoto

Publications and source records attributed to M Kawamoto.

At least 37 records · Page 2Linked to original sources
PubMed2001

Propofol relaxes extrapulmonary artery but not intrapulmonary artery through nitric oxide pathway.

The object of this study was to compare vasorelaxing responses to propofol by the intrapulmonary artery (IPA) and the extrapulmonary artery (EPA), and to identify the mechanisms of action. Rat pulmonary arterial rings were isolated and suspended in organ chambers where isometric tension development was measured under optimal resting tension. All pulmonary arterial rings were pre-contracted with phenylephrine. Propofol (Diprivan) and the vehicle (10% Intralipid) were administered cumulatively in the presence or absence of N(omega)-nitro-L-arginine methyl ester (L-NAME). Sodium nitroprusside (SNP), a nitric oxide donor, was administered cumulatively. Propofol relaxed both EPA and IPA in a dose dependent manner (p<0.05), while the vehicle alone showed no effect. The vasorelaxing responses to propofol were significantly higher in EPA than IPA at higher concentrations (10(-4) M and 10(-4.5) M) (p<0.05), and were decreased by L-NAME in EPA (p<0.05), though it had no effect in IPA. The concentration for SNP causing 50% relaxation was not significantly different between the two arteries. We concluded that the response of smooth muscle to nitric oxide was the same between EPA and IPA; however, the vasorelaxing mechanisms of propofol seemed to be different between them at higher doses, suggesting that a mechanism exists and operates through the nitric oxide pathway.

Animals↗
PubMed2001

[A comparison of finger and nose probes in pulse dye-densitometry measurements of cardiac output, blood volume and mean transit time].

We compared finger and nose probes in measurement of cardiac output (CO), blood volume (BV) and mean transit time (MTT) with pulse dye-densitometry. These probes were intraoperatively applied to 6 patients under general and continuous epidural anesthesia. Indocyanine green (ICG) 20 mg, was given via peripheral venous route, and CO, BV and MTT were measured with DDG-2001 (NihonKoden, Japan). Eighteen measurements were done successfully. There was no significant difference between F-CO (CO with a finger probe, 4.48 +/- 1.40 l.min-1, mean +/- SD) and N-CO (CO with a nose probe, 4.14 +/- 1.87 l.min-1). F-MTT (32.9 +/- 11.1 sec) was significantly longer than N-MTT (19.9 +/- 6.4 sec, P < 0.01). The limits of agreement of F-CO and N-CO (mean difference +/- 2 SD) were -3.6 and +4.2 l.min-1, respectively. There was a significant negative correlation between differences in MTT and F-CO/N-CO (R2 = 0.448, P < 0.01). There was no significant difference between F-BV (3.97 +/- 1.23 l) and N-BV (3.97 +/- 0.98 l). The limits of agreement of F-BV and N-BV were -1.3 and +1.3 l, respectively. In conclusion, the measured values in BV showed good agreement and reliability with both finger and nose probes, while CO was less reliable when differences in MTT increased.

Anesthesia, Epidural↗
PubMed2001

A formula based on body length for determining the size of an uncuffed endotracheal tube for pediatric cardiac anesthesia.

Three hundred and thirty-four pediatric patients less than 4 years old who underwent surgery for congenital heart disease were retrospectively studied to devise a practical formula for predicting the appropriate size for an uncuffed endotracheal tube for pediatric cardiac anesthesia. Furthermore, this formula was compared with that for non-cardiac anesthesia obtained from 409 patients without congenital heart disease. A simple regression equation between tube size and body length resulted in the simple predictive formula: "tube size = 0.04 x body length + 1.6" for pediatric cardiac anesthesia. This formula had the same slope and an approximately 0.3 mm larger intercept on the Y-axis compared with that for pediatric non-cardiac anesthesia. Therefore, a one-size larger endotracheal tube is more suitable for use in pediatric cardiac anesthesia than in pediatric non-cardiac anesthesia for the same body length.

Anesthesia↗
PubMed2000

Longitudinal elongation of primary afferent axons in the dorsal funiculus of the chick embryo spinal cord.

The longitudinal elongation of primary afferent axons (PAAs) in the dorsal funiculus of chick embryo spinal cord was examined using a lipophilic tracer, DiI and immunohistochemistry. The earliest developing PAAs in the brachial segments invaded the spinal cord around embryonic day (E) 3.5. Thereafter, they elongated both rostrally and caudally in the presumptive dorsal funiculus, with frequent contacts between pre-existing axons and later arriving growth cones. By E4, the PAAs had elongated 3 segments both rostrally and caudally. In the course of their longitudinal elongation, the PAAs shifted their trajectory dorsally within the dorsal funiculus. By E6-6.5, the PAAs had extended as far as 10 segments rostrally and 6 segments caudally in the dorsal funiculus, and collaterals began to enter the dorsal horn. By E9, the PAAs extended up to 13 segments rostrally and 7 segments caudally, and collaterals reached the ventral spinal cord. During their longitudinal course, the PAAs shifted their trajectory medially within the dorsal funiculus.

Afferent Pathways↗
PubMed2000

Structural basis for the higher Ca(2+)-activation of the regulated actin-activated myosin ATPase observed with Dictyostelium/Tetrahymena actin chimeras.

Replacement of residues 228-230 or 228-232 of subdomain 4 in Dictyostelium actin with the corresponding Tetrahymena sequence (QTA to KAY replacement: half chimera-1; QTAAS to KAYKE replacement: full chimera) leads to a higher Ca(2+)-activation of the regulated acto-myosin subfragment-1 ATPase activity. The ratio of ATPase activation in the presence of tropomyosin-troponin and Ca(2+) to that without tropomyosin-troponin becomes about four times as large as the ratio for the wild-type actin. To understand the structural basis of this higher Ca(2+)-activation, we have determined the crystal structures of the 1:1 complex of Dictyostelium mutant actins (half chimera-1 and full chimera) with gelsolin segment-1 to 2.0 A and 2.4 A resolution, respectively, together with the structure of wild-type actin as a control. Although there were local changes on the surface of the subdomain 4 and the phenolic side-chain of Tyr230 displaced the side-chain of Leu236 from a non-polar pocket to a more solvent-accessible position, the structures of the actin chimeras showed that the mutations in the 228-232 region did not introduce large changes in the overall actin structure. This suggests that residues near position 230 formed part of the tropomyosin binding site on actin in actively contracting muscle. The higher Ca(2+)-activation observed with A230Y-containing mutants can be understood in terms of a three-state model for thin filament regulation in which, in the presence of both Ca(2+) and myosin heads, the local changes of actin generated by the mutation (especially its phenolic side-chain) facilitate the transition of thin filaments from a "closed" state to an "open" state. Between 394 and 469 water molecules were identified in the different structures and it was found that actin recognizes hydrated forms of the adenine base and the Ca ion in the nucleotide binding site.

Actins↗
PubMed2000

Effects of pneumoperitoneum on cardiac autonomic nervous activity evaluated by heart rate variability analysis during sevoflurane, isoflurane, or propofol anesthesia.

BACKGROUND: The effects of pneumoperitoneum on the activity of the cardiac autonomic nervous system have not been completely understood. METHODS: In this study, 45 unpremedicated adult patients who underwent laparoscopic cholecystectomy were anesthetized with either 3.5% sevoflurane, 2% isoflurane, or 8 mg/kg/h propofol (15 patients in each group). The status of cardiac autonomic nervous activity was evaluated by heart rate variability analysis three times: once when the patient was awake, once after induction of general anesthesia, and once after insufflation for pneumoperitoneum. Intra-abdominal pressure was maintained automatically at 10 mm Hg by a carbon dioxide (CO(2)) insufflator. For each measurement, electrocardiogram was recorded for 256 s and played back offline to detect R-R intervals. Power spectral analysis of heart rate variability was applied, and the low-frequency (LF, 0.04-0.15 Hz) and high-frequency (HF, 0.15-0. 40 Hz) bands of the spectral density of the heart rate variability were obtained from a power spectra of R-R intervals using the fast-Fourier transform algorithm. The HF/LF ratio also was analyzed. RESULTS: Measurements of heart rate variability in the three groups showed similar change. Although the power of HF, which represents parasympathetic nervous activity, did not change, the power of LF, which represents both sympathetic and parasympathetic nervous activity, decreased during the anesthetized stage and increased during the insufflated stage. The HF/LF ratio, which represents the balance of parasympathetic and sympathetic activity, increased after induction of general anesthesia, and decreased after insufflation. CONCLUSIONS: Our results suggest that pneumoperitoneum increases sympathetic cardiac activity. The choice of general anesthetic did not seem to have a major influence on the change in the cardiac autonomic nervous system after induction of pneumoperitoneum for laparoscopic cholecystectomy.

Adult↗
PubMed2000

Pharmacokinetic profile of propofol after a single-dose injection during general anesthesia in Japanese adults.

PURPOSE: To determine the pharmacokinetic parameters of propofol after a single-dose injection in Japanese adults. METHODS: This study was carried out in adult patients who underwent minor surgery under general anesthesia with sevoflurane. We injected 1.0, 1.5, or 2.0 mg.kg(-1) of propofol at a constant rate using a syringe pump. Arterial blood samples were taken for 480 min after the administration of propofol. The whole-blood concentration of propofol was determined with gas chromatography, and a time-blood concentration curve was analyzed by a two-compartment open-model analysis and a model-independent analysis. RESULTS: The half-lives of the central and peripheral compartment ( t(1/2)alpha and t(1/2)beta) were 2.26 +/- 0.69 and 47.9 +/- 22.1 min, respectively. The volume of the central compartment (V(c)) was 0.582 +/- 0.170 l.kg(-1), and the apparent volume of distribution at a steady state (V(dss)) was 2.62 +/- 1.06 l.kg(-1). The total body clearance (Cl) and mean residence time (MRT) were 53.7 +/- 11.9 ml.min(-1).kg(-1) and 98.1 +/- 16.4 min, respectively. CONCLUSIONS: Among the pharmacokinetic parameters determined in Japanese adults, t(1/2)alpha, t(1/2)beta, and Vc were similar, V(dss) was smaller, and Cl was larger, as compared with values in Caucasians. These findings suggest that propofol could be eliminated well during minor surgery in Japanese adults.

Journal Article↗
PubMed2000

Effects of one-lung ventilation on cardiac autonomic nervous activity as evaluated by power spectral analysis of heart rate variability.

The purpose of this prospective study was to evaluate the effects of one-lung ventilation on the activity of the cardiac autonomic nervous system. Ten adult patients who underwent thoracotomy were endotracheally intubated with a double-lumen tube under general anesthesia using isoflurane. After induction of anesthesia, a continuous, 256-sec electrocardiogram (ECG) was obtained during bilateral lung ventilation (control) followed by recordings during one-lung ventilation of each side. Using the R-R interval tachograms obtained for the 256-sec ECGs, low frequency (LF: 0.04-0.15 Hz) and high frequency (HF: 0.15-0.40 Hz) bands of the spectral density of the heart rate variability and the HF/LF ratio were analyzed using the fast Fourier transform algorithm. Log(HF), which indicates parasympathetic activity, increased during one-lung ventilation on each side, but did not differ between ventilated sides. Log(LF), which represents sympathetic and parasympathetic activity, increased similarly to log(HF) on both sides. Log(HF/LF), the balance of the sympathetic and parasympathetic activity, did not change during one-lung ventilation. We suggest that one-lung ventilation alone does not substantially affect the cardiac autonomic nervous system.

Adult↗
PubMed2000

Changes in the activities of protein phosphatase type 1 and type 2A in sea urchin embryos during early development.

In the eggs and embryos of sea urchins, the activity of protein phosphatase type 2A (PP2A) increased during the developmental period between fertilization and the morula stage, decreased after the prehatching blastula stage and increased again after hatching. The PP2A activity changed keeping pace with alteration to the activities of cAMP-dependent protein kinase (A kinase), Ca2+/calmodulin-dependent protein kinase (CaM kinase) and casein kinase. Probably, PP2A contributes to the quick turning off of cellular signals because of protein phosphorylation. The activity of protein phosphatase type 1 (PP1) was not detectable up to the morula stage and appreciably increased thereafter. In the isolated nucleus fraction, specific activities of PP1 and PP2A were higher than in whole embryos at all stages in early development. Exponential increase in the number of nuclei because of egg cleavage probably makes PP1 activity detectable in whole embryos after the morula stage. In isolated nuclei, the activities of PP1 and PP2A appreciably decreased after hatching, whereas the activities of A kinase, Ca2+/phospholipid-dependent protein kinase (C kinase) and CaM kinase, as well as casein kinase, became higher. In nuclei, cellular signals caused by protein phosphorylation after hatching do not seem to be turned off by these protein kinases so quickly as before hatching. The PP1 and PP2A in nuclei also seem to contribute to the elimination of signal noise.

Animals↗
PubMed2000

Elastosis in lung carcinoma: immunohistochemical, ultrastructural and clinical studies.

Elastosis is the pathological finding of focal deposits of elastic fibers in abnormal amounts within tissue. It is well described in the case of infiltrating carcinoma of the breast, but elastosis in lung carcinoma has not been previously documented in detail. We investigated the characteristics of elastosis in lung carcinoma with light and electron microscopies, and immunohistochemistry for alpha-1-antitrypsin. A total of 184 surgically resected primary lung carcinomas were studied. Elastosis was detected in adenocarcinomas (85/106), squamous cell carcinomas (11/60) and adenosquamous carcinomas (5/7), but not in small-cell carcinomas (n = 4) or large-cell carcinomas (n = 5). The degree of elastosis in each case was divided into one of five grades, graded as 3+ to 1-. The score of elastosis was significantly higher in adenocarcinoma than that in squamous-cell carcinoma (P<0.01). In the cases of adenocarcinoma, the mean score of elastosis in the well-differentiated type (WD n = 43) was higher than that in the moderately differentiated (MD) (n = 39; P = 0.012) and poorly differentiated (PD) types (n = 24; P<0.01). The mean score of elastosis in MD adenocarcinoma was also higher than that in the PD type (P<0.01). Light- and electron-microscopic analyses revealed that these elastic fibers in elastosis were composed of aggregates of thick mature and fine immature elastic fibers, and were positive for alpha-1-antitrypsin. It is suggested that both degraded elastic fibers and newly synthesized fibers are contained in the elastosis of lung carcinoma. Although no significant evidence was detected to suggest any correlation between elastosis and the degree of tumor invasion, the survival curves of adenocarcinomas with elastosis showed a significantly improved prognosis than of those without elastosis in the cases of stages IA and IB (n = 52; P = 0.026).

Adenocarcinoma↗
PubMed2000

[Two cases of hypoxemic acute bronchiolitis due to Mycoplasma pneumoniae].

Two males with acute bronchiolitis due to Mycoplasma (M.) pneumoniae, aged 24 and 39 years were reported. They presented prolonged cough and fever in the early stage of the disease. Chest X-rays of those patients showed diffused nodular shadows. Chest CT scan showed diffused nodular shadows and thickning of bronchovascular marking. Blood-gas analysis indicated hypoxemia without abnormal A-aDO2. We diagnosed two patients as M. pneumoniae infection by antibody assays. The Eosinophil cationic protein (ECP) level and IgE level were high. Eosinophilia and endotoxemia were also observed in two patients. We speculated that the allergic reaction and endotoxemia may be related to hypoxemia and the clinical severity of M. pneumoniae infection.

Acute Disease↗
PubMed2000

Matrix metalloproteinase and tissue inhibitor of metalloproteinase in human bone marrow tissues-an immunohistochemical study.

Unlike other tissues, bone marrow (BM) seldom displays fibrosis after injury, suggesting a possible suppressive mechanism against secondary myelofibrosis in BM tissues. We investigated if fibrosis-related factors, such as matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase (TIMP), were expressed in BM tissues in vivo. We attempted immunohistochemical studies on specimens of 16 BM aspiration materials with normal hematological findings and 21 BM tissues from autopsy cases who had succumbed to acute heart failure or cerebrovascular diseases without any BM injuries. Identification of immunohistochemically reactive MMP-2, MMP-9 and TIMP-2 in BM tissue samples revealed for the first time that MMP-2 was localized in the myeloid cells, erythroblasts and megakaryocytes, MMP-9 in the myeloid cells and megakaryocytes. In addition, expression of TIMP-2 in the megakaryocytes as well as in the histiocytes within the stroma was verified. In the non-pathological condition, MMP/TIMP expressions were not encountered in BM stromal cells, such as fibroblasts, vascular endothelial cells, reticulum cells on adipocytes, except for TIMP-2 identification in stromal histiocytes. It is highly possible that these MMP and TIMP expressions in the BM hematopoietic cells and stromal histiocytes are significantly associated with suppression or induction of myelofibrosis.

Adult↗
PubMed2000

[Reliability of electrogustatory threshold--electrogustometry using CNV].

CNV (contingent negative variation), an event-related potential, is induced when an oncoming imperative stimulus (S2) is anticipated after recognition of a warning stimulus (S1). With this in mind, we assessed the usefulness of electrogustometry using CNV as an objective gustatory test with an electric gustatory stimulus as a warning stimulus, S1. A gustatory test was performed on a total of 100 sides of the tongue in 50 subjects. Excluding no response cases on 5 sides in 5 subjects, the CNV threshold was successfully determined on 95 sides in 50 subjects. When the CNV threshold values obtained and the conventionally measured subjective threshold values were compared, a very high correlation was demonstrated between the two thresholds, with a correlation coefficient of 0.961. To assess the reliability of the CNV threshold, three additional measurements on 5 sides in 5 subjects with normal subjective threshold values were performed on different days, and the CNV threshold value variation among the three measurements in all 5 subjects never exceeded 13 microA. Separately, subjective threshold and CNV threshold values were compared in 4 patients with facial palsy (hence with gustatory abnormality) who consented to a follow-up examination. The difference between the subjective threshold and CNV threshold values in all 4 patients never exceeded 10 microA. These findings demonstrate that the reliability of the CNV threshold is satisfactory. Next, a gustatory imitation experiment was performed to assess the usefulness of electrogustometry using CNV as a means of detecting gustatory abnormality malingering. The experiment was performed on a total of 6 subjects: 3 physicians with knowledge of CNV (knowledge group) and 3 others with no knowledge of CNV (no-knowledge group). The differences between the imitated threshold and the subjective threshold values in all of these subjects never exceeded 10 microA, and the difference between imitated threshold and CNV threshold values never exceeded 13 microA. Comparison between the knowledge group and the no-knowledge groups showed that the imitated threshold values were very close to the subjective threshold and CNV threshold values. Based on the above results, it was concluded that gustometry using CNV is useful and can serve well as a method of objective evaluation of gustatory sensation. The results also suggested that it will be useful in diagnosing malingering.

Adolescent↗
PubMed2000

Albumin permeability across endothelial cell monolayer exposed to reactive oxygen intermediates: involvement of reversible functional alteration of the cell membrane Ca2+ channels.

This study was designed to test the idea that the redox state of sulfhydryl (SH)-groups in cell-membrane Ca2+ channels plays a pivotal role in Ca2+ influx, which in turn causes an increase in albumin permeability across the cultured monolayer of porcine pulmonary artery endothelial (PPAE) cells exposed to xanthine/xanthine oxidase (X/XO). Albumin permeability as well as the concentration of intracellular Ca2+ ([Ca2+]i) was increased by X/XO. A H2O2 scavenger (catalase), an iron chelator (o-phenanthroline), and a hydroxyl radical scavenger (dimethyl sulfoxide) inhibited these changes provoked by X/XO, in which intracellular iron-catalyzed hydroxyl radical generation was suggested to be involved. The increase in albumin permeability and [Ca2+]i continued once the PPAE cells were exposed to X/XO. The [Ca2+]i was decreased by a Ca2+ channel blocker, Ni2+, while the removal of Ni2+ increased [Ca2+]i again, suggesting the sustained Ca2+ influx through cell-membrane Ca2+ channels was responsible for the [Ca2+]i elevation. Ni2+ failed to inhibit albumin permeability sustained after the removal of X/XO. In contrast, SH-reducing agents (dithiothreitol and glutathione) inhibited the sustained permeability as well as Ca2+ influx. We concluded that the redox alteration of SH-groups in cell-membrane Ca2+ channels was involved in the increase in albumin permeability after exposure of the endothelial cells to oxidative stress.

Albumins↗
PubMed2000

[Risk of bradycardia after endoscopic electrocautery of the upper thoracic sympathetic ganglia].

We evaluated risk of bradycardia after endoscopic electrocautery of the upper thoracic sympathetic ganglia (ETS). Enrolled in this study were 24 patients. Bradycardia, defined as heart rate below 50 beats per min continuing for more than 5 min, was found in 12 patients (50%). All patients were divided into two groups; bradycardia group and non-bradycardia group. Age, sex, region of electrocautery, fentanyl dosage, and operation time were not different between the two groups. Power spectral analysis of heart rate variability revealed that sympathetic activity decreased after ETS. Multivariate analysis indicates that postoperative-minimal heart rate depends upon preoperative heart rate at rest. We conclude that careful monitoring after ETS is necessary in a patient with heart rate below 60 bpm preoperatively.

Aged↗
PubMed2000

[Pain management for patients with cancer--current problems in a pain clinic].

One hundred and twenty-three patients with early or advanced cancer who had been referred to our pain clinic were studied retrospectively to investigate current problems with pain management for cancer patients. Pain due to advanced cancer and prolonged post-thoracotomy pain were two major reasons for referral. It was found that 51.7% of the patients with advanced cancer had not been treated appropriately with the WHO protocol for cancer pain relief before referral; however, increased administration of morphine did not necessarily relieve cancer pain, and in fact decreased the QOL of some patients; and 47.7% of patients with cancer pain were effectively treated with nerve block therapy. The present investigation also indicates that many patients who had undergone thoracotomy suffered prolonged post thoracotomy pain. Although post-thoracotomy pain was refractory to NSAIDs, trigger point injections with or without intercostal nerve block were effective in 65.4% of such patients. We conclude that further propagation of the WHO protocol for cancer pain relief, appropriate use of nerve block and establishment of practical guidelines for multidisciplinary management of pain are mandatory for improving the QOL of patients with cancer.

Aged↗
PubMed2000

Elastosis in lung carcinoma: Immunohistochemical, ultrastructural and clinical studies.

Elastosis is the pathological finding of focal deposits of elastic fibers in abnormal amounts within tissue. It is well described in the case of infiltrating carcinoma of the breast, but elastosis in lung carcinoma has not been previously documented in detail. We investigated the characteristics of elastosis in lung carcinoma with light and electron microscopies, and immunohistochemistry for alpha-1-antitrypsin. A total of 184 surgically resected primary lung carcinomas were studied. Elastosis was detected in adenocarcinomas (85/106), squamous cell carcinomas (11/60) and adenosquamous carcinomas (5/7), but not in small-cell carcinomas (n = 4) or large-cell carcinomas (n = 5). The degree of elastosis in each case was divided into one of five grades, graded as 3+ to 1-. The score of elastosis was significantly higher in adenocarcinoma than that in squamous-cell carcinoma (P < 0.01). In the cases of adenocarcinoma, the mean score of elastosis in the well-differentiated type (WD n = 43) was higher than that in the moderately differentiated (MD) (n = 39; P = 0.012) and poorly differentiated (PD) types (n = 24; P < 0.01). The mean score of elastosis in MD adenocarcinoma was also higher than that in the PD type (P < 0.01). Light- and electron-microscopic analyses revealed that these elastic fibers in elastosis were composed of aggregates of thick mature and fine immature elastic fibers, and were positive for alpha-1-antitrypsin. It is suggested that both degraded elastic fibers and newly synthesized fibers are contained in the elastosis of lung carcinoma. Although no significant evidence was detected to suggest any correlation between elastosis and the degree of tumor invasion, the survival curves of adenocarcinomas with elastosis showed a significantly improved prognosis than of those without elastosis in the cases of stages IA and IB (n = 52; P = 0.026).

Adenocarcinoma↗