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T Katoh

Publications and source records attributed to T Katoh.

At least 361 records · Page 20Linked to original sources
PubMed1993

Influence of age on awakening concentrations of sevoflurane and isoflurane.

We determined whether age, duration of anesthesia, gender, or type of surgery significantly influenced end-tidal concentrations on awakening from anesthesia with sevoflurane and isoflurane in 39 healthy ASA physical status I patients. Postoperatively, the end-tidal anesthetic concentration was maintained at a constant level at least for 15 min. If patients failed to open their eyes on request, the end-tidal concentration was decreased and again maintained at a constant level for 15 min. The anesthetic concentration midway between the value permitting the response and that just preventing the response was recorded. The end-tidal concentrations on awakening from anesthesia were 0.62 +/- 0.02% (mean +/- SE) for sevoflurane and 0.41 +/- 0.02% for isoflurane. Awakening concentration of sevoflurane and isoflurane correlated significantly with age (P < 0.001), but not with duration of anesthesia, gender, or type of surgery. The authors conclude that awakening concentration decreases at the similar rate of decrease in minimum alveolar concentration (MAC) with increasing age; and therefore, the ratios to MAC are fairly constant, being 0.34 for both sevoflurane and isoflurane.

Adult↗
PubMed1993

Osteogenesis in sintered bone combined with bovine bone morphogenetic protein.

Bone morphogenetic protein (BMP) was combined with true bone ceramic (TBC) in an attempt to produce a bone grafting material possessing the cancellous structure, osteoconductivity, and osteoinductivity of biologic bone. To determine the osteogenetic ability of this material (BMP-TBC) within bone marrow, BMP-TBC and TBC alone were implanted in the femoral condyles of Japanese White rabbits, and histographs of these implants, taken serially, were compared. Woven bone formation was observed both at the periphery and within surface pores of the BMP-TBC implants one week after implantation; these implants thus became secured to the host bone bed at an earlier stage than did TBC alone. The amount of new bone formation increased at a significantly higher rate with BMP-TBC than with TBC alone during the first four weeks. Therefore the BMP in BMP-TBC implants acts at an early stage on BMP-responding cells entering the pores of the TBC. These data also suggest that TBC, as a carrier for BMP, provides a favorable environment for the promotion of new bone formation.

Animals↗
PubMed1993

[The establishment of a monolayer culture system of guinea pig chief cells and an enzyme immunoassay system for guinea pig pepsinogen].

For the purpose of studying pepsinogen secretion from gastric chief cells, we established a monolayer culture system of guinea pig chief cells and an enzyme immunoassay (EIA) system specific for guinea pig pepsinogen. Dispersed chief cells were obtained from gastric mucosa of a guinea pig using collagenase, GEDTA, and Percoll solution, suspended in DMEM/F-12 (1/1 containing 10% FCS) media, and cultured for 70hr. Then the monolayer culture system was established. Pepsinogen was purified from gastric mucosa of a guinea pig using DEAE-Sephacel and Sephacryl S-200 columns. Antibody to pepsinogen was raised by immunizing rabbit with the purified pepsinogen. A two-site EIA system was then established using beta-galactosidase-labeled Fab' antibody. The EIA system showed sensitivity to measure above 1.5ng of guinea pig pepsinogen, and the monolayer culture system responded well to secretagogues. These systems are useful for studying pepsinogen secretion.

Animals↗
PubMed1993

[Influences of 5'-deoxy-5-fluorouridine (5'-DFUR) on cell cycle in patients with breast cancer].

Recently, the effectiveness of preoperative chemotherapy for cancer treatment has attracted much attention. The authors conducted a study to investigate the influence of 5'-DFUR administration on the cell cycle, based on DNA analysis using FCM in patients with breast cancer. A total of 53 patients with breast cancer (Stages I, II and III) were investigated concerning tumor PyNPase activity and cell cycle phase. Subjects were stratified according to tumor diameter, histologic type and ER in the group receiving preoperative 5'-DFUR administration (25 patients) and the group not receiving 5'-DFUR (28 patients). The subjects in the group on 5'-DFUR preoperative administration were classified into three sub-groups according to total dosages of 400 mg (8 patients), under 4,800 mg (8 patients) and 4,800 mg or over (9 patients). In terms of tumor diameter, significant increases (p = 0.027) of S-phase were observed in patients with the diameters of 5 cm or more in the sub-group of under 4,800 mg dosage. Similar tendencies were seen in all drug administration groups (p = 0.05). However, no influence was observed on S-phase in the group without 5'-DFUR administration. In terms of ER stratification, ER(-) patients in the dosing groups showed increasing tendencies in S-phase and significant differences of G1- as well as G2+M phases. No differences in PyNPase activity were noted in each stratified group. Preoperative administration of 5'-DFUR resulted in alterations of cell cycle in breast cancers. In patients with a total drug dosage of under 4,800 mg and with tumor diameters of 5 cm or more, increases of S-phase and decreases of G1-phase were observed. It was suggested that 5'-DFUR acted in DNA synthesizing stage to accumulate S-phase inhibiting cell cycles. Consequently, this drug is considered useful for neoadjuvant chemotherapy.

Antineoplastic Agents↗
PubMed1992

Ethnic differences of the primary gene defect at the cytochrome P-450 2D6.

The cytochrome P-450-dependent monooxygenase system is involved in the metabolism of both endogenous compounds and xenobiotics. The role of these enzymes in toxicological response is exemplified by an autosomal recessive polymorphism at the cytochrome P-450 2D6 debrisoquine-4-hydroxylase locus, which results in the severely impaired metabolism of many drugs [Gough et al. (1990) Nature 347: 773-776]. The prevalence of this polymorphism (poor metabolizer) differs considerably between ethnic groups. Here we analyzed the P-450 2D6 polymorphism in 25 Japanese and 20 Chinese by DNA-based genetic assay using peripheral leukocyte. Although the phenotype of all the normal metabolizers and 79% of the poor metabolizers could be identified in Caucasians, this DNA-based genomic assay could not predict poor metabolizers in both the Japanese and Chinese. These results indicate that the genetic mechanism of the phenotyped poor metabolizer in Orientals is different from that in Caucasians.

Asian People↗
PubMed1992

The mechanism of the action of IFN-gamma and TPA on the modulation of epidermal growth factor receptors of human amnion cells.

We have examined the mechanism of synergistic action occurring between interferon (IFN)-gamma and 12-0-tetradecanoylphorbol-13-acetate (TPA) with respect to the reduction of 125I-epidermal growth factor (125I-EGF) binding to human amnion (WISH) cells [Karasaki Y et al (1989) J Biol Chem 264: 6158-6163]. The cells were treated with protein kinase C (PKC) inhibitors (H7, staurosporine) to investigate the role of PKC in the synergism between IFN-gamma and TPA, since TPA is a strong activator of PKC. The combined effect of IFN-gamma and TPA was blocked by the PKC inhibitor, suggesting that PKC plays an important role in the synergistic action of TPA and IFN-gamma on the inhibition of EGF binding to the cells. The prolonged incubation (24 h) of the cells with TPA resulted in the restoration of EGF binding to the cells. A 24 h treatment of WISH cells with both IFN-gamma and TPA, however, still exhibited greater than 50% inhibition of EGF binding. No PKC activity, however, was observed in the WISH cells treated with both IFN-gamma and TPA for 24 h as well as with TPA alone for 24 h, indicating that IFN-gamma may synergize with the second mediator induced by PKC rather than PKC itself in the reduction of EGF binding to WISH cells. In addition, IFN-gamma showed the synergistic action with calcium ionophores on the reduction of EGF binding to the cells, suggesting that Ca2+ may be one of the second mediators which was induced by TPA and which cooperated with IFN-gamma.

Amnion↗
PubMed1992

Differences of L-myc polymorphic patterns of neuroblastoma in patients under 1 year versus older ages: a preliminary report.

The age of the patient at the onset of symptoms or at diagnosis is generally accepted as one of the most important prognostic factors of neuroblastomas (NBs). Children less than 1 year of age have a better survival rate than older patients, but the reason for this is unknown. Forty-eight unselected NB patients were divided into two groups: less than 1 year (younger NB patient) and over 1 year (older NB patient) of age at diagnosis. Two of 12 younger NB patients and 18 of 36 older NB patients had N-myc amplification in their tumors. To elucidate further the possible genetic difference between younger and older NB patients, studies of restriction fragment length polymorphism (RFLP) of the L-myc gene was carried out in these two groups. The L-myc locus showed 2-allele polymorphism, allele L(10 kb) and S (6.6 kb), after digestion with EcoRI. Patients homozygous for L-band have been reported as individuals having less metastatic potential in some cancers. The allele frequencies of L and S in neuroblastomas of younger NB patients were 0.50 and 0.50, while those of older NB patients were 0.35 and 0.65, respectively. Although we did not determine L-myc RFLP in normal tissue of individual patients, we expect that the distribution of allele L and S is partly affected by possible allelic loss involving the L-myc region. However, the L-myc RFLP patterns in younger NB patients were the same as those of normal individuals and significantly differed from those of older NB patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1992

Differential responsiveness of normal and simian virus 40-transformed human fibroblast cells to interferon-gamma.

The effect of interferon-gamma (IFN-gamma) on epidermal growth factor (EGF) receptor binding and the proliferation of normal and simian virus 40 (SV40)-transformed human fibroblast cells was compared under identical culture conditions. IFN-gamma induced an enhancement of EGF binding to normal cells, whereas it decreased the EGF binding to SV40-transformed cells. Half-maximal enhancement occurred at 72 h after the normal cells were exposed to 10 U/ml of IFN-gamma, and maximal stimulation was obtained at about 10(2) U/ml of IFN-gamma at 72 h. On the other hand, half-maximal reduction was observed for SV40-transformed cells at less than 10 U/ml of IFN-gamma at 72 h, and maximal reduction was obtained at around 10(3) U/ml of IFN-gamma at 72 h. Scatchard analysis indicated that the number of EGF binding sites of normal and SV40-transformed cells was calculated to be 1.6 x 10(5) and 0.88 x 10(5) per cell, respectively, and was little altered by IFN-gamma treatment. The dissociation constant (Kd) of normal cells, however, decreased from 4.5 nM (control) to 2.0 nM (IFN-gamma-treated), while the Kd of SV40-transformed cells increased from 3.6 nM (control) to 17.0 nM (IFN-gamma-treated). The immunoprecipitation of 125I-labeled EGF-bound EGF receptors with anti-receptor antiserum indicated that a 72-h IFN-gamma treatment did not induce a conformational alteration in the EGF receptors of both normal and transformed cells. The DNA synthesis of normal cells was enhanced by EGF, and IFN-gamma treatment potentiated the effect of EGF on DNA synthesis, probably due to the increased binding affinity of EGF to the cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Transformation, Viral↗
PubMed1992

Minimum alveolar concentration of sevoflurane in children.

We have determined the minimum alveolar concentration (MAC) value of sevoflurane in 20 children, of both sexes, aged 3-5 yr. MAC was found to be 2.49 (SE 0.08)%, which was greater than that of adults in our previous study. The ratio of MAC values between children and adults is similar to that reported elsewhere for enflurane and isoflurane, but not for halothane. The anaesthetic ED95 that prevented 95% of patients from moving was 2.88%.

Anesthesia, Inhalation↗
PubMed1992

Blood concentrations of sevoflurane and isoflurane on recovery from anaesthesia.

We studied 16 healthy ASA physical status I patients (aged 13-71 yr for sevoflurane and 22-74 yr for isoflurane) to determine maximum blood concentrations on awakening (MBCawake) from sevoflurane and isoflurane anaesthesia, and determined if age and duration of anaesthesia significantly influenced MBCawake. After operation, the end-tidal concentration of anaesthetics was decreased gradually. During recovery from anaesthesia, patients were asked repeatedly to open their eyes. We obtained blood samples to measure the anaesthetic concentration when patients first opened their eyes. MBCawake of sevoflurane and isoflurane (ml of anaesthetic gas per ml of blood) were 0.40 (SE 0.04)% and 0.53 (0.04)%, respectively. MBCawake values of sevoflurane and isoflurane correlated significantly with age (P < 0.05) but not with duration of anaesthesia. Blood:gas partition coefficients of sevoflurane and isoflurane were 0.65 (SD 0.05) and 1.36 (0.09), respectively. There was no significant correlation between age and blood:gas partition coefficient for sevoflurane and isoflurane. Awakening alveolar concentrations (MACawake) calculated from MBCawake were 0.61 (SE 0.05)% for sevoflurane and 0.39 (0.02)% for isoflurane, and correlated significantly with age. The ratios of awakening alveolar concentration to MAC were reasonably constant--0.33 for sevoflurane and 0.33 for isoflurane.

Adolescent↗
PubMed1992

Comparison of Ki-ras gene mutation among simultaneously occurring multiple urethan-induced lung tumors in individual mice.

Mouse lung tumors were induced in C57BL/6J(female) x A/J(male) F1 mice by a single s.c. injection of urethan. About 6 months later, multiple small-sized lung tumors were detectable in almost all mice. After a further 6 months, some of these tumors became larger than the rest. We examined whether there were any mutational differences among multiple lung tumors in a single mouse. Direct DNA sequencing of a separately amplified Ki-ras gene by polymerase chain reaction (PCR) was carried out with 25 DNA samples from multiple tumors in four mice. Twenty-four of 25 tumors (96%) had mutations at the codon 61 of the Ki-ras gene. The major mutations involved were either AT to GC transition (44%) or AT to TA transversion (44%) at the second base of codon 61. We compared the types of these gene mutations among the tumors from each of two mice from two different groups of siblings and then compared the two groups. Interestingly, in the first group of siblings, we detected CTA in 5/6 tumors in the first mouse and again CTA in 4/6 tumors in the second one. In the second group of siblings, we detected CGA in 5/7 tumors in one mouse and CGA again in 3/5 tumors in the second mouse. These results show that the pattern of Ki-ras codon 61 mutations in urethan-induced lung tumors is similar in tumors developing in siblings, suggesting that host factors have an effect on the carcinogen-induced mutational pattern. There was no major mutational difference between small and large tumors. The results suggested that other event(s) in addition to the mutation of the Ki-ras gene might play a role during the development of large-sized tumors.

Amino Acid Sequence↗
PubMed1992

Amino acid sequence of the 20-kDa regulatory light chain of porcine aorta media smooth muscle myosin.

The amino acid sequence of the 20-kDa regulatory light chain (LC20) of myosin from porcine aorta media smooth muscle was determined. The LC20 consisted of 171 amino acid residues and its N-terminal Ser residue was blocked by an acetyl group. The amino acid sequence was identical with that of chicken gizzard myosin LC20 except that the 60th residue, Met in chicken gizzard LC20, was substituted for Leu in porcine aorta LC20.

Amino Acid Sequence↗
PubMed1992

A case of cardiac foreign bodies associated with four types of tachycardias.

A case of cardiac foreign bodies leading to development of four varieties of automatic tachycardia is reported. A 51-year-old male with aortic regurgitation was admitted to our hospital because of palpitations. An electrocardiogram revealed junctional tachycardia with or without left bundle branch block, and two types of fascicular tachycardias. Computed tomography showed metallic foreign bodies from a fractured guidewire in the membranous portion of the interventricular septum, which was inadvertently retained when he underwent diagnostic cardiac catheterization at the age of 27.

Bundle-Branch Block↗
PubMed1992

[Nested polymerase chain reaction for the diagnosis and follow-up of tuberculous meningitis: a case report].

We presented a case of tuberculous meningitis in which a nested polymerase chain reaction was useful for its rapid diagnosis and follow-up. A 5-month-old girl was hospitalized for gastrointestinal complaints of 4 days' duration. She initially had no meningeal signs, but showed a bulging of the anterior fontanel on the 10th day of her illness. Cerebrospinal fluid examination revealed a cell count of 886/3 microliters (80% lymphocytes), protein of 20 mg/dl, and glucose of 27 mg/dl. Tuberculous meningitis was suspected clinically and an antituberculous therapy was commenced on the 13th day. Although repeated attempts to culture Mycobacterium tuberculosis were negative, the DNA of the organism was detected sequentially from the cerebrospinal fluid of the 13th and 16th day by the method of a nested polymerase chain reaction. The final diagnosis of tuberculous meningitis was established on the basis of the positive results of the nested polymerase chain reaction, a positive tuberculin test, and typical cerebrospinal fluid findings. She recovered rapidly in response to the therapy and was discharged from the hospital without any neurological sequelae on the 89th day. The follow-up samples of the nested polymerase chain reaction resulted as negative after the 26th day of the illness.

Female↗
PubMed1992

Renal hemodynamic actions of lipoxins in rats: a comparative physiological study.

Interactions between either the arachidonate 5-lipoxygenase (5-LO) and 15-LO or 5-LO and 12-LO can lead to the formation of lipoxins. Although the functional significance of lipoxygenase products of arachidonic acid has been recognized increasingly in glomerular inflammation, less is known regarding the specific effects of lipoxins on renal hemodynamics. Here, we examine the renal actions of lipoxin (LX) A4, LXB4, and, the recently identified 7-cis-11-trans-LXA4, which were administered into the renal artery of the euvolemic male Munich-Wistar rat. LXA4 caused increases in renal plasma flow (RPF) and glomerular filtration rate (GFR) in a dose-dependent manner. These effects were reversed during cyclooxygenase inhibition. LXB4 decreased both RPF and GFR, and its mode of action was independent of cyclooxygenase activity. 7-cis-11-trans-LXA4 decreased RPF and GFR, which effects were abolished during systemic infusion of the leukotriene D4 receptor antagonist SKF 104353. Results indicate that each of these lipoxins displays distinct hemodynamic effects via a specific mode of action on the renal vasculature of rats. Moreover, they suggest mechanisms whereby lipoxins may participate in the changes of renal hemodynamics that occur during glomerular inflammatory processes.

Animals↗
PubMed1992

Paroxysmal atrial fibrillation and flutter associated with acute myocardial infarction: hemodynamic evaluation in relation to the development of arrhythmias and prognosis.

The hemodynamic background associated with the occurrence of paroxysmal atrial fibrillation and flutter (PAF), in patient with acute myocardial infarction (AMI) were evaluated. Sixty-seven of 381 consecutive AMI patients (17.6%) were noted to have PAF in the acute phase of infarction. These 67 patients with PAF (group 1) were compared with 60 randomly selected patients without PAF (group 2). The hospital mortality rate was 25.4% in group 1, and 11.7% in group 2 (p less than 0.01). The hemodynamic variables measured before the onset of PAF in group 1, showed significantly more unfavorable values than those in group 2, which were measured at the time of admission. The 67 patients in group 1 were divided into 50 patients who survived (group S) and 17 patients who died in the hospital (group D). The hemodynamic status in group D demonstrated significantly larger deterioration before the onset of PAF than in group S. Hemodynamic variables were compared before and during PAF in groups D and S, cardiac index (CI) decreased significantly, and stroke index (SI) decreased by 46% in group D, with no decrease in CI and less decrease in SI (28. p less than 0.05) in group S. In conclusion, not only the occurrence of PAF, but the prognosis of patients with PAF is dependent on the severity of hemodynamic disturbance imposed by AMI. Atrial contribution to ventricular filling has great importance in the maintenance of the cardiac output in this patient population.

Aged↗
PubMed1992

Isolation and serial propagation of porcine epidemic diarrhea virus in cell cultures and partial characterization of the isolate.

Porcine epidemic diarrhea virus (PEDV) was isolated in Vero cell cultures from the small intestine of a piglet experimentally infected with porcine coronavirus 83P-5, that had been isolated during outbreaks of porcine acute diarrhea and passaged in piglets. The isolation of the PEDV was successful only in Vero cells maintained in the maintenance medium (MM) containing trypsin. Infected Vero cell cultures exhibited CPE characterized by cell-fusion and syncytial formation, as well as cytoplasmic fluorescence when examined by the indirect immunofluorescent test using rabbit anti-83P-5 virus serum. The isolate was adapted to serial propagation in Vero cell cultures by adding trypsin to MM. Vero cell-adapted PEDV was successfully propagated in the MA104, CPK and ESK cell lines in the presence of trypsin in MM. Vero cell-adapted PEDV had morphologic and physicochemical characteristics similar to those of other members of the coronaviridae. The isolate differed serologically from porcine transmissible gastroenteritis (TGE) and porcine hemagglutinating encephalomyelitis viruses, and no antigenic relationship between the isolate and TGE virus could be detected by the indirect immunofluorescent test. Attempts to isolate PEDV in 6 types of primary fetal pig cell cultures and 6 of 10 established cell lines resulted in the failure, probably because these cells were damaged by the action of trypsin.

Animals↗