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Biomedical subjects

H Katayama

Publications and source records attributed to H Katayama.

At least 181 records · Page 10Linked to original sources
PubMed1995

Alterations in DNA and cell membranes in an initiation process of carcinogenesis by N-nitrosourea.

We examined DNA alkylation of rat organs (liver, stomach, kidney, lung, and brain) treated with a tissue specific carcinogen, N-methyl-N'-(beta-naphthyl)-N-nitrosourea (MNaNU) (200 mg/kg wt.). There is no correlation between the level of O6-methylguanine (O6-MeG) and formation of tumors with these organs. Fourier-transform infrared (FT-IR) spectra of the treated tissues were compared with those obtained form the non-treated organs in the region between 1000 and 1350 cm-1. The infrared spectra of the treated stomach which is a target organ for induction of tumors showed the formation of hydrogen bonding in carbohydrates, disturbance of nucleic acid structures, and presence of disordered states in the membranes. Further, the stomachs were divided into the forestomachs (target tissue) and glandular stomachs, and their FT-IR spectra were also examined. Using 1134 cm-1 band due to the C-H plane bending of the naphthyl ring of MNaNU, we estimated approximately 0.82 mg of MNaNU would persist in the forestomach of one rat at 6h after administration. The present results demonstrate importance of pharmacokinetics and receptor sites in cell membrane in addition to DNA alkylation for carcinogenesis by directly acting N-nitroso compounds.

Alkylating Agents↗
PubMed1994

Determination of 18 beta-glycyrrhetic acid in human plasma by high-performance liquid chromatography.

A sensitive high-performance liquid chromatographic method has been developed for the determination of 18 beta-Glycyrrhetic acid in human plasma. 18 alpha-Glycyrrhetic acid was used as an internal standard. The procedure includes pretreatment by liquid-liquid extraction and chromatographic separation on a reversed-phase column with ultraviolet detection. The detection limit of the drug was 5 ng/ml. The method was applied to the determination of 18 beta-glycyrrhetic acid in plasma after oral administration of a herbal medicine containing 18 beta-glycyrrhitic acid in human volunteers.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1994

Evaluation of the radiographic efficacy of iomeprol.

Iomeprol, a new nonionic contrast medium, was administered at concentrations of 300 mgI/ml, 350 mgI/ml, and 400 mgI/ml to 1939 Japanese patients. The radiographic efficacy, the incidence of heat sensation and the incidence of pain were evaluated. The radiographic efficacy was rated as excellent in 80.6% and good in 17.5% of 1017 cases of conventional arteriography, excellent in 75.6% and good in 22.2% of 267 cases of IADSA or IVDSA, excellent in 78.3% and good in 19.6% of 384 cases of intravenous urography and excellent in 68.6% and good in 28.8% of 271 cases of CT enhancement. There was no statistical difference in radiographic efficacy between the sites of arteriography. Heat sensation was mild or moderate in 43.4% and severe in 0.2% of cases requiring intra-arterial injection, and mild or moderate in 50.7% of cases requiring intravenous injection. There were no cases of severe heat sensation following intravenous injection. The incidence of pain was low (mild 4.2%, moderate 0.7% and severe 0.1%) with intra-arterial injections. It is concluded that iomeprol is an excellent radiographic contrast medium for intravenous urography, CT enhancement and various forms of angiography.

Adolescent↗
PubMed1994

Assessment of the side-effects of iomeprol.

Adverse reactions were investigated in a group of 1918 patients enrolled in a study for the clinical assessment of iomeprol. The incidence of adverse reactions in the group was 5.3%. Dermatological symptoms were the principal adverse reactions. No previously unreported side-effects from iodinated contrast media were detected. Most adverse reactions were of slight or moderate intensity and most appeared within 3 h of the injection. The examinations which elicited a comparatively high frequency of adverse reactions were cerebral angiography, abdominal angiography, peripheral angiography, intravenous urography and thoracic angiography. No significant sex differences were noted with respect to the occurrence of adverse reactions, but such effects were more frequent among younger patients, among patients with allergic conditions and among patients who had previously received iodinated contrast media. As regards the manner of injection of iomeprol, there were no definite trends in terms of the iodine concentration used or the quantity of contrast medium injected, but the incidence of adverse reactions was comparatively high for intravenous as compared with intra-arterial injection.

Adult↗
PubMed1994

Solute absorption from the airways of the isolated rat lung. IV. Mechanisms of absorption of fluorophore-labeled poly-alpha,beta-[N(2-hydroxyethyl)-DL-aspartamide].

The pulmonary absorption kinetics of a single molecular weight distribution (MWD) of fluorophore-labeled poly-alpha,beta-[N(2-hydroxyethyl)-DL-aspartamide] (F-PHEA), a hydrophilic and biocompatible synthetic polypeptide, were studied in the isolated, perfused rat lung (iprl) as functions of administered polymer concentration, dose, vehicle, and presence and absence of fluorophore. The MWD was characterized before and after absorption by measurement of weight- and number-averaged molecular weights (Mw and Mn, respectively) using high-performance gel-permeation chromatography. Values for Mw and Mn were 8.6 and 5.3 kD before, and 6.7 and 4.7 kD after, absorption into the perfusate; there was no significant metabolism and the MWD of the absorbed polymer was independent of both dose and sampling time over a 3-hr period. F-PHEA failed to show any evidence of aggregation in solution or changes in dose distribution within the airways as functions of increasing polymer concentration and dose. A concentration ranging study indicated the presence of a saturable, carrier-mediated transport process for F-PHEA with a maximum absorption rate, Vmax, of approximately 180 micrograms or 0.027 mumol/hr. Coadministration of fluorophore-free PHEA was capable of depressing the absorption of F-PHEA. The transport process for F-PHEA appeared to have a molecular weight limit of about 7 kD for this hydrophilic polymer.

Absorption↗
PubMed1994

Purification and characterization of two Kunitz family subtilisin inhibitors from seeds of Canavalia lineata.

Two subtilisin inhibitors (CLSI-II and -III) were purified from seeds of Canavalia lineata by extraction with water, ammonium sulfate precipitation, and chromatographies on DEAE-Toyopearl and hydroxyapatite. The two inhibitors have the same molecular weight of about 22,000, and quite similar amino acid compositions. They contain five half-cystine residues and tend to dimerize through an intermolecular disulfide bridge due to the presence of a single cysteine residue. CLSI-III only inhibited subtilisin-type serine proteases, while CLSI-II showed a wider inhibitory specificity. Though the two inhibitors have almost identical thermal labilities, CLSI-II is more stable as to extreme pH than CLSI-III. They are considered to be Kunitz type inhibitors on the basis of several properties.

Amino Acid Sequence↗
PubMed1994

Amino acid sequences of Kunitz family subtilisin inhibitors from seeds of Canavalia lineata.

The amino acid sequences of two subtilisin inhibitors (CLSI-II and -III) from Canavalia lineata seeds were determined by manual Edman degradation using the DABITC/PITC double coupling method after enzymatic digestions and CNBr degradation. CLSI-II and -III consist of 190 and 183 amino acids, respectively, and have identical amino acid sequences except for in the C-terminal regions: an elongated sequence, Gly-Thr-Ile-Arg- Ser-Asp-Gly, was found at the C-terminus of CLSI-II. A short-chain analog protein without an N-terminal Asn residue was also detected in each inhibitor preparation. The inhibitors showed significant homology to Kunitz type inhibitors, but differed from them with respect to the half-cystine content. Among five half-cystine residues present in CLSI-III, two disulfide bonds link Cys44 to Cys88 and Cys142 to Cys149, Cys106 being present as a free cysteine residue. Phenylglyoxal treatment abolished the inhibitory activity of CLSI-III, indicating the participation of an Arg residue in the interaction with the enzyme. The reactive-site peptide bond was deduced to be Arg68-Gly69.

Amino Acid Sequence↗
PubMed1994

Cardiac myxoma with Gamna-Gandy bodies: case report with MR imaging.

We describe a patient with a left atrial tumor that showed very unusual magnetic resonance (MR) imaging features. Postsurgical histologic examination showed characteristics of myxoma, and Gamna-Gandy bodies were found in the tumor. We believe that the unusual MR appearance was caused by the hemosiderin in the Gamna-Gandy bodies.

Aged↗
PubMed1994

Detachment of cultured normal human keratinocytes by contact with TNF alpha-stimulated neutrophils in the presence of platelet-activating factor.

We have found previously that the cultured human squamous cell carcinoma cell line DJM-1 detached from the substratum after 48 h contact with human neutrophils. Neutrophils appeared to become activated by contact with DJM-1 and were found to secrete a proteinase that caused the detachment; the proteinase was inhibitable by alpha 1-proteinase inhibitor. In this study we tested whether normal human keratinocytes were also detached from the substratum by contact with human neutrophils, because keratinocyte detachment (epidermal separation) occurs in several skin diseases with neutrophil infiltration beneath the epidermis. Neutrophils with or without tumor necrosis factor (TNF) alpha pretreatment were plated on keratinocytes at confluency in 24-well culture plates, co-cultured in serum-free media for 16-24 h in the presence or absence of platelet-activating factor (PAF), and assessed for rate of detachment by counting the undetached keratinocytes and by fluorescent dye labeling. Keratinocytes were found to detach only when TNF alpha-pretreated neutrophils were plated together with 10(-5) M PAF. Inhibiting direct contact between neutrophils and keratinocytes by means of a membrane filter, however, decreased the detachment markedly. alpha 1-proteinase inhibitor and ONO-5046, a synthetic elastase specific inhibitor, inhibited the detachment significantly, and alpha 1-antichymotrypsin inhibited it slightly. The mediator responsible for detachment appeared to be elastase. Monoclonal anti-CD18 inhibited the detachment only partially. In conclusion, TNF alpha-pretreated neutrophils appeared to be activated by contact with keratinocytes in the presence of 10(-5) M PAF and caused substantial detachment of keratinocytes, possibly by secreting elastase. The precise role of PAF in detachment remains to be clarified.

Antibodies↗
PubMed1994

Noninvasive estimation of left ventricular Max(dP/dt) from aortic flow acceleration and pulse wave velocity.

The Doppler method of obtaining left ventricular Max(dP/dt) proposed recently was based on the measurement of mitral regurgitation velocity. Since Max(dP/dt) is an isovolumic phase index, its use in cases of mitral regurgitation may be open to argument. However, we had proposed a noninvasive method of estimating left ventricular Max(dP/dt) based on different principles. In our method, Max(dP/dt) had been given by Max(dP/dt) = (rho)cMax (du/dt), where rho is the blood density, c is the pulse wave velocity, and u is the flow velocity in the aorta. We had derived the above equation theoretically, and confirmed its validity by animal experiments. In our previous study, we also applied our method in the clinical setting. The aortic flow velocity was measured by Doppler echocardiography, and the pulse wave velocity by mechanocardiography or Doppler echocardiography. (Rho)cMax(du/dt) obtained noninvasively was compared with Max(dP/dt) measured with a catheter-tip micromanometer. We found an excellent correlation between (rho)cMax(du/dt) and Max(dp/dt), and concluded that (rho)Max(du/dt) is useful in assessing noninvasively the contractile state of the left ventricle. Here, we summarize our method, review previous results, and report new results of the clinical application of our method.

Blood Flow Velocity↗
PubMed1994

Decrease in ventricular stroke volume at apnea termination is independent of oxygen desaturation.

Patients with obstructive sleep apnea experience nocturnal hemodynamic oscillations in association with repetitive respiratory events. Apnea termination (recovery) is accompanied by the nadir of arterial O2 saturation (SaO2), changes in intrathoracic pressure, and arousal from sleep. To investigate separately the contributions of hypoxemia and of arousal from sleep to changes in cardiac function, we continuously measured left ventricular stroke volume (LVSV) and mean arterial pressure (MAP) in eight subjects with severe obstructive sleep apnea (apnea-hypopnea index > 30 events/h associated with SaO2 < or = 82%) during two experimental conditions: 1) subjects slept without intervention for 1-2 h and then supplemental O2 was administered to maintain SaO2 > or = 90% (mean SaO2 nadir 92.7%) throughout the apnea-recovery cycle and 2) upper airway obstructions were abolished using nasal continuous positive airway pressure and subjects were aroused from sleep by an auditory signal. Recovery was associated with an increase in MAP and a decrease in LVSV both with and without supplemental O2. Arousal from sleep on nasal continuous positive airway pressure reproduced the postapneic elevation of MAP but not a decrease in cardiac function of the magnitude that occurred at apnea termination. We conclude that elevation of blood pressure and reduction of LVSV that occurred at apnea termination may be due to different physiological mechanisms.

Adult↗
PubMed1994

Property and amino acid sequence of a subtilisin inhibitor from seeds of beach canavalia (Canavalia lineata).

A subtilisin inhibitor was purified from the seeds of Canavalia lineata by ammonium sulfate precipitation, ultrafiltration on a YM-30 membrane, column chromatography on DEAE-Toyopearl and SP-Toyopearl, followed by reverse-phase HPLC. The inhibitor (CLSI-I) is a low molecular weight protein (M(r) about 6500) containing no half-cystine residue, and quite stable as to extreme heat and pH treatment. CLSI-I inhibited subtilisin-type serine proteases including S. griseus alkaline protease. The amino acids of CLSI-I were sequenced by manual Edman degradation after enzymatic digestion with Achromobacter lyticus lysyl endopeptidase and Staphylococcus aureus V8 protease. CLSI-I contains 65 amino acid residues and showed a high homology to potato inhibitor I family proteins.

Amino Acid Sequence↗
PubMed1994

[Analysis of p53 gene in gynecologic tumors].

The inactivation of the tumor suppressor gene p53 has been demonstrated in a variety of human tumors. Herein, we performed a p53 gene analysis of human gynecologic tumor cell lines and tumor tissues. In the SK-OV-3 cell line, Southern analysis suggested the presence of sequence deletions/rearrangements in at least one allele of p53 gene. Transcripts were not detectable by either Northern or PCR analysis. Sequencing analysis of the entire coding region revealed mutations changing the p53 amino acid composition in all six endometrial carcinoma cell lines tested (Ishikawa, Hec1-A, Hec1-B, KLE, RL95-2, and AN-3), and four cell lines in ovarian carcinoma cell lines (Caov-3, -4, OVCAR-3, and Kuramochi). Of the seven cervical carcinoma cell lines, two (HT-3 and C-33A) contained p53 codon changes. We were unable to detect the human papilloma virus (HPV) in these two cell lines. By contrast, five HPV-positive cervical carcinoma cell lines (HeLa S-3, Caski, SiHa, C-41, and ME-180) contained wild-type p53 gene sequences. Examination of loss of heterozygosity (LOH) by PCR revealed that about 30% of the human ovarian carcinoma tissues has LOH at the locus of p53 gene. We suggest that, in the HPV-positive cervical tumors, p53 inactivation occurred via the known mechanism of viral E6/cellular p53 protein association, whereas in all other tumors (ovarian carcinoma, endometrial carcinoma, HPV-negative cervical carcinoma) p53 function was compromised by changes in the amino acid sequence.

Base Sequence↗
PubMed1993

Structural alterations of the chloroplast genome found in grasses are not common in monocots.

The distribution of structural rearrangements of the chloroplast genome found in grass cpDNA in comparison to that of tobacco was systematically checked in the cpDNAs of representative monocots. The physical map of lily cpDNA, which shares a key position in the diversity of monocotyledonous plants, was constructed to assess whether three inversions found in grass cpDNA are common in monocots. Specific probes for the detection of (1) intron loss in the rpoC1 gene, (2) insertional sequence gain in rpoC2, (3) deletion of ORF2280 in the inverted repeats, (4) non-reciprocal translocation of rpl23, and (5) rearrangements of ORF512, were hybridized to cpDNAs of lily, onion, spiderwort, two turf grasses, and wheat. The existence of intervening sequences in the rpoC1 and rpoC2 genes was also confirmed by PCR analysis. All markers used in the study revealed that structural rearrangements of the chloroplast genome were restricted to grasses, indicating that drastic structural alterations of the chloroplast genome had occurred in the ancestor(s) of grasses. These results also suggest that structural analysis of the chloroplast genome is applicable to the phylogenetic reconstruction of related plants.

Base Sequence↗
PubMed1993

Prominent telangiectasia associated with marked bleeding in CREST syndrome.

A 64-year-old woman with CREST syndrome developed prominent telangiectases mimicking hereditary hemorrhagic telangiectasia (HHT) of Osler-Rendu-Weber. We have been following her since she first came to us with discrete telangiectatic mats and Raynaud's phenomenon 11 years ago. Telangiectatic lesions have been seen on her larynx and esophagus in addition to commonly affected sites. She has experienced spontaneous epistaxis and marked bleeding from the lesions on her lips, oral mucous membrane, and soles. This case illuminates new aspects of telangiectasia in CREST syndrome.

Calcinosis↗
PubMed1993

Induction of right ventricular hypertrophy with obstructing balloon catheter. Nonsurgical ventricular preparation for the arterial switch operation in simple transposition.

BACKGROUND: Recently, a successful result with a rapid two-stage arterial switch operation (ASO) was reported for patients with transposition of the great arteries (TGA) with low left ventricular pressure. In this procedure, the interval between pulmonary arterial banding and ASO was approximately 1 week. This successful result indicates the possibility of a nonsurgical ventricular preparation procedure using an obstructing balloon catheter prior to ASO. METHODS AND RESULTS: A 5F atrioseptostomy catheter was inserted directly into the main pulmonary artery in six lambs aged 20 to 38 days. After the chest was closed, the balloon was inflated twice a day for a period of 2 to 2.5 hours. This procedure was performed for 4 consecutive days. After the final inflation, the ratio of right ventricular weight to total ventricular weight was compared with that in an age-matched control group. After the final inflation, the peak systolic right ventricular pressure and the percentage of peak systolic right ventricular to peak systolic aortic pressure rose to 85.6 +/- 4.7 mm Hg (mean +/- 1 SD) and 79.6 +/- 8.6%, respectively. The percentages of the right ventricular weight to the total ventricular weight were significantly higher after the balloon inflation than those in the control group in terms of wet heart weight (29.5 +/- 1.2% versus 23.0 +/- 1.0%; P < .0001) and dry heart weight (27.0 +/- 2.0% versus 21.0 +/- 1.1%; P < .0001). CONCLUSIONS: The myocardial mass in the right ventricle increased after 4 days of intermittently applied pressure overload. Nonsurgical preparation of the ventricle for ASO in TGA is feasible.

Animals↗
PubMed1993

[Structure-activity relationship of flavonoids in suppressing rat liver lipid peroxidation].

145 flavonoids were studied for their inhibitory effects on the iron-induced lipid peroxidation in mitochondria obtained from rat livers. Of these compounds tested, 30, 57, 59, 67, 70, 72, 77, 102 and 110 (ED50 < or = 0.5 nmol/mg prot) showed distinctly more potent inhibitory activity than baicalein (ED50 < or = 5 nmol/mg prot) and 59 and 72 (ED50 < or = 0.05 nmol/mg prot) exhibited the most potent activity. In order to elucidate the relationships between substituents on the flavonoid skeleton and the biological activity, the quantitative structure-activity relationships (QSAR) were analyzed by the adaptive least-squares (ALS) method for 142 flavonoids. The analysis has shown that the presence of the 1,4- and 1,2-hydroquinone in A-ring and/or B-ring of flavonoids and hydrophobicity of the molecule are responsible for the in vitro inhibitory activity.

Animals↗