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Biomedical subjects

T Katoh

Publications and source records attributed to T Katoh.

At least 289 records · Page 16Linked to original sources
PubMed1995

Biological monitoring of occupational exposure to methyl ethyl ketone in Japanese workers.

The relationship between occupational exposure to methyl ethyl ketone (MEK) and its concentration in urine and blood was studied in a group of 72 workers in a printing factory. Personal exposure monitoring was carried out with passive samplers during the workshifts. The time weighted average (TWA) concentration of MEK ranged from 1.3 to 223.7 ppm, with a mean concentration of 47.6 ppm. In addition to MEK, toluene, xylene, isopropyl alcohol, and ethyl acetate were detected as the main contaminants in all samples. At the end of the workshift, urine samples were collected to determine the urinary MEK, hippuric acid (HA), and creatinine, and blood samples were also collected at the same time for determination of MEK. The concentrations of urinary MEK ranged from 0.20 to 8.08 mg/L with a mean of 1.19 mg/L and significantly correlated with TWA concentrations of MEK in the air with a correlation coefficient of 0.889 for uncorrected urine samples. The concentration of MEK in the blood was also significantly correlated with the TWA concentration of MEK with a correlation coefficient of 0.820. From these relationships, MEK concentrations in urine and blood corresponding to the threshold limit value-TWA (200 ppm; ACGIH 1992) were calculated to be 5.1 mg/L and 3.8 mg/L as a biological exposure index (BEI), respectively. Although the BEI for urinary MEK obtained from the present study was higher than that of previous reports and ACGIH's recommendation (2.0 mg/L), the BEI agreed well with a previous study in Japan.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Elevation of ratio of urinary N-acetylneuraminlactose to free sialic acid in some advanced cancer patients.

We estimated the levels of free sialic acid and sialylated oligosaccharides excreted in the urine of normal donors (n = 10) and patients with gastric cancer (n = 6) and colorectal cancer (n = 4). The total sialic acid level in cancer patients was similar to that in normal donors. However, the ratios of glycosidically bound sialic acids to free sialic acid were higher in some advanced cancer patients than in the normal donors. A major component of sialylated oligosaccharides was N-acetylneuraminyl alpha (2-->3) lactose. The elevation of the urinary ratio of this sialylated oligosaccharide to free sialic acid observed in some advanced cancer patients in this study may reflect the elevation of sialyltransferase activity in tumor tissues.

Adult↗
PubMed1995

Electron microscopic study of endogenous peroxidase activity in human liver macrophages.

We evaluated the conditions of fixation for ultrastructurally demonstrating the endogenous peroxidase (PO) activity of macrophages in biopsied human liver. The application of microwaving and immersion fixation with tannic acid and aldehydes allowed excellent visualization of PO activity in the nuclear envelope (NE), rough endoplasmic reticulum (rER), and cytoplasmic granules (CG), with good preservation of cellular ultrastructures. The macrophages with PO activity showed one of the following five patterns of PO localization: positive in both the NE and rER but negative in the CG (type 1); negative in both the NE and rER but positive in the CG (type 2); negative in the NE but positive in both the rER and CG (type 3); positive in all three (type 4); PO negative (type 5). The type 1 cells resembled typical Kupffer cells, type 2 cells monocytes, and type 3 and 4 cells the exudate-resident macrophages considered to be a transitional form between exudate and resident macrophages. Type 5 cells may also be a transitional form between the exudate and resident macrophage, or an end-stage macrophage derived from exudate macrophages which have lost their PO activity. Tannic-acid-aldehyde immersion fixation with microwaving may be a useful method in the study of the PO activities of macrophages in biopsied human liver specimens.

Cell Nucleus↗
PubMed1995

GAP-43 mRNA suppression by the ribozyme in PC12 cells and inhibition of evoked dopamine release.

We constructed a ribozyme designed to cleave the GAP-43 mRNA and which contained a bacteriophage T7 transcription terminator at its 3' site to maintain stability. The ribozyme was overexpressed in PC12 cells by pEF-BOS, a powerful mammalian expression vector. Consequently, PC12 cells overexpressing the GAP-43 ribozyme revealed a drastic decrease in the levels of GAP-43 mRNA expression, and the evoked dopamine release was significantly suppressed in these cell lines. These results support the previous observations that GAP-43 is associated with Ca-dependent dopamine release in PC12 cells, and the ribozyme expression system used in the present study was demonstrated to be useful for suppression of the functions of specific mRNAs and exploration of specific gene products.

Animals↗
PubMed1995

Severe cerebellar atrophy following acute cerebellitis.

The clinical course and serial magnetic resonance imaging findings of a 4-year-old girl with acute cerebellar ataxia due to acute cerebellitis are described. Multifocal white matter lesions visualized by magnetic resonance imaging in both cerebellar hemispheres in the acute phase disappeared in the convalescent phase. Cerebellar signs became less prominent within 2 weeks, but mild ataxic gait remained. During the follow-up period of 32 months, there was a gradual development of cerebellar atrophy along with a recurrence of cerebellar ataxia.

Acute Disease↗
PubMed1995

Highly efficient adenovirus-mediated gene transfer into renal cells in culture.

In summary, we have shown that adenovirus vector efficiently introduced foreign gene into cultured renal cells both of mesangial and tubular origin. Genes transferred were properly expressed to produce the molecules of expected function. It was possible to introduce the gene into nearly 100% of the cells treated. Expression of the gene began as early as 12 hours after the infection, increased until 48 hours and persisted at least up to eight days. Finally, the vector was non-toxic to the cells, as judged from simple toxicity tests. Successful application of adenovirus vector enables for us to study function of pertinent molecules in suitable host cells and opens a new way for examining renal cellular physiology and pathophysiology.

Adenoviruses, Human↗
PubMed1995

Cytochrome P4501A1 gene polymorphism and homozygous deletion of the glutathione S-transferase M1 gene in urothelial cancer patients.

Japanese urothelial (bladder, renal pelvis and ureter) cancer patients (n = 83) and community controls (n = 101) were compared for rates of polymorphism in exon 7 of the cytochrome P4501A1 (CYP1A1) gene or homozygous deletion of the glutathione S-transferase class mu (GSTM1) gene. A CYP1A1 polymorphism was detected in a HinCII polymorphism assay utilizing a primer with a single base pair mismatch. The frequency distribution of the CYP1A1 genotypes in urothelial cancer patients showed no significant difference from that in healthy controls. The increased frequency of homozygous deletions of GSTM1 gene loci in patients with urothelial cancer was statistically significant compared with the controls, 51 of 83 (61%) and 43 of 101 (43%) (odds ratio = .2.15, 95% confidence interval = 1.18-3.86). These results lead us to conclude that homozygous deletion of the GSTM1 gene may be associated with susceptibility to urothelial cancer.

Adult↗
PubMed1995

Evidence for involvement of a 12-residue peptide segment of the heavy chain in the neck region of smooth muscle myosin in formation of the 10S conformation.

Two synthetic peptides having amino acid sequences of the heavy chain segments in the neck region of porcine aorta smooth muscle myosin were used to study the formation of the 10S folded conformation. These peptides, MHC821-835 and MHC835-846, correspond to residues 821-835 and 835-846, respectively, of the chicken gizzard myosin heavy chain. The effects of these peptides on the filament formation of porcine aorta smooth muscle myosin were examined. The filamentous myosin fraction increased on the addition of MHC835-846 at NaCl concentrations lower than 0.25 M for both dephosphorylated and phosphorylated myosin, while the filament formation of dephosphorylated myosin was unaffected by the addition of MHC821-835 up to 30 microM. The filaments formed in the presence of MHC835-846 were observed by electron microscopy to be morphologically indistinguishable from those formed in the absence of the peptide. Rotary shadowed images of dephosphorylated myosin monomers revealed mostly the 10S form in the absence of MHC835-846, while the 6S form was predominant in the presence of the peptide. The results indicate that MHC835-846 inhibits the formation of the 10S conformation. On cosedimentation assaying with myosin, rod and light meromyosin, MHC835-846 bound to each of them with a stoichiometry of nearly 1 mol/mol heavy chain. Altogether, these results suggest that the region in the myosin heavy chain corresponding to MHC835-846 may be involved in the binding site for the light meromyosin portion of myosin for formation of the 10S conformation.

Amino Acid Sequence↗
PubMed1995

Crosslinking of a 28-residue N-terminal peptide of actin to myosin subfragment 1.

The N-terminal 28-residue peptide of actin whose Cys10 was labeled with 5-iodoacetamido-fluorescein (F3K peptide) was isolated from the fluorescently labeled thrombin digest of actin. The effect of myosin subfragment 1 (S1) on the fluorescence of F3K peptide was examined in the absence of ATP. With increasing concentration of S1 added, the fluorescence intensity of F3K peptide increased by maximally 7.3% with an apparent dissociation constant of 5.7 microM, suggesting a role of this peptide region of actin in acto-S1 binding in rigor. F3K peptide was crosslinked with S1 at 10 mM NaCl using a zero-length crosslinker by the method of Grabarek and Gergely [Anal. Biochem. 185, 131-135 (1990)]. The crosslinking was greatly inhibited by the presence of either 0.2 M NaCl or 5 mM MgATP. The analyses of amino acid compositions and sequences of the fluorescent peptides isolated from a lysylendopeptidase digest of the crosslinked S1 indicated that F3K peptide was mainly crosslinked to residues 637-642 of the S1 heavy chain. The crosslinked S1 was isolated by selectively pelleting the uncrosslinked S1 with F-actin. ATPase activity of the isolated crosslinked S1 alone was twice as high as that of control S1. The actin-activated ATPase activity of the crosslinked S1 was much lower than that of uncrosslinked S1. The estimated Vm and Km values were 1.72 s-1 and 125 microM, respectively. The Vm decreased to less than 1/8, while Km increased only twofold. The results suggest that the N-terminal 28-residue segment of actin may be implicated in the rigor binding of actomyosin and in the actin-activation of myosin ATPase, but may not be the main determinant of actomyosin binding in the presence of ATP.

Actins↗
PubMed1995

Incidence of human parvovirus B19 DNA detection in blood donors.

1000 serum samples from blood donors were tested for human parvovirus B19 (B19) DNA by a nested PCR assay: six samples were positive for B19 DNA. The frequency was 1/167 (0.6%), considerably higher than previous surveys (0.004-0.03%). Five of the six samples were also positive for anti-B19 IgM, indicating an acute phase of infection. It is recommended to screen for B19 DNA in blood products to prevent transfusion mediated viral infection for those susceptible such as immunocompromised patients and pregnant women.

Antibodies, Viral↗
PubMed1995

Sex differential in life expectancy in Japan and Scotland: age and causes of death.

The contribution of age groups and causes of death to the sex difference in life expectancy (SDLE) at birth in Japan and Scotland was estimated for the period 1965-1990. The purpose was to determine the particular age groups and causes of death responsible for the opposite trend of SDLE in the two countries. SDLE has been widening and narrowing in Japan and Scotland, respectively. The availability of complete and reliable data for these two developed countries facilitated the study. A method of decomposing the total SDLE into age and cause of death components was employed. About 40-60% contribution to SDLE was observed for ages after 65 years. Marked increase in the contribution of the 75+ age group and marked decrease in the contribution of ages 45-64 for Japan and Scotland, respectively, had a major effect on the widening and narrowing of SDLE in the two countries, respectively. The contribution of diseases of the circulatory system was the maximum until 1980 in Japan (< or = 1.8 years or 33.6%; cerebrovascular disease alone < or = 23.4%) and until 1990 in Scotland (< or = 3.1 years or 47.0%; ischemic heart disease alone < or = 42.0%). In Japan, the contribution of malignancy had a marked increased from 0.7 year (12.3%) to 2.0 years (32.6%), particularly for the trachea, bronchus and lung, while there was only a small increase in Scotland from 1.0 year (16.6%) to 1.2 years (19.8%) with an increase in the negative contribution of female breast malignancy. In Japan, the contribution of diseases of the respiratory system increased considerably from 0.5 year (8.5%) to 1.1 years (18.1%) while it decreased in Scotland from 1.0 year (16.5%) to 0.6 year (10.7%). About 60-75% of SDLE is due to the above three groups of causes of death. Malignancy and diseases of the respiratory system had a persistently increased contribution in Japan with resultant widening of SDLE by 0.9 year. Diseases of the circulatory system have always had a high contribution. On the contrary, in Scotland the contribution of diseases of the circulatory system and malignancy was practically unchanged and diseases of the respiratory system had a decrease with a consequent narrowing of SDLE by 0.4 year. Further epidemiological study is necessary to detect and analyze in detail the internal gradients (environmental and genetic-biological) of major contributor diseases to SDLE in Japan and Scotland.

Adolescent↗
PubMed1995

A rapidly progressive case of interstitial pneumonia.

We treated a 51-year-old woman who had rapidly progressive respiratory distress with an interstitial shadow on chest roentgenogram. Pathologically, open lung biopsy specimens showed an acutely changed lesion such as interstitial inflammatory thickening, polypoid intraluminal organizing exudates, and also honeycombing which was not recognized on chest computed tomogram. These findings were considered unconformable to acute interstitial pneumonia (AIP), bronchiolitis obliterans organizing pneumonia (BOOP), and also usual interstitial pneumonia, although the clinical diagnosis was AIP or BOOP. We diagnosed a rapidly progressive interstitial pneumonia showing an acute lung injury pattern like AIP and BOOP. She showed significant recovery with corticosteroid and cyclophosphamide.

Acute Disease↗
PubMed1995

[Evaluation of late potential by using--event-related signal-averaging technique].

UNLABELLED: Event-related (ER) signal-averaging technique was used to evaluate whether beat-to-beat changes of filtered QRS complex possibly relate to the appearance of ventricular arrhythmias (VA) or not. 82 patients with premature ventricular contractions (PVC) were studied. ANALYSIS-I:56 pts (16 with VT): a conventional method, in which all sinus beats were averaged (ALL), was compared with the new ER methods, in which only sinus beats immediately before (B) or after (A) each PVC can be separately averaged. ANALYSIS-II: 26 pts (10 with VT): five modes of ER averaging, 2nd preceding (2-B), just preceding (1-B), immediately after (1-A), 2 beat after (2-A), and isolated (ISO) from each PVC, were compared. RESULT: I: Significantly longer F-QRS and smaller RMS40 than ALL were observed at B both in VT+ and VT- pts. These transient changes tended to remain even at A only in VT+ not in VT+ pts.II: No significant changes compared with ISO were seen at 2-B and 2-A at all. The widening of F-QRS and the decrease of RMS40 occurred only at 1-B in VT- and unti 1-A in VT+ pts. In conclusion, pre- and post- extra-systolic changes of filtered QRS complex were very transient and event-related, suggesting the close relationship to the mechanism of VA.

Adult↗
PubMed1995

[Clinical evaluation of patients with cardiopulmonary bypass by plasma granulocyte elastase].

To evaluate the role of granulocyte elastase (GEL) at cardiopulmonary bypass (CPB), the plasma GEL level was measured in 24 patients who underwent elective cardiac surgery and 47 patients who underwent elective gastroenterological surgery. The cardiac surgical patients were divided into two groups: 5 patients with CPB less than 120 minutes (HL group), and 19 patients with CPB more than 120 minutes (HH group). The patients with gastro-enterological surgery were also divided into two groups: 15 patients with postoperative complications (GC group), and 32 patients without postoperative complications (GU group). All the patients of GU, HL and HH groups were alive. Two patients of GC group died because of multiple organ failure (MOF). The serum levels of GEL in both the HH group and the GC group remained higher than in the GU group at 6 postoperative day (POD). The high serum level of IL-8 gave rise to high serum level of GEL in the HH group, even after cardiac surgery. We assumed that anti-cytokine therapy and aggressive administration of Ulinastatin are useful against postoperative complications and that careful management is need after long CPB.

Cardiac Surgical Procedures↗