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Biomedical subjects

T Shibamoto

Publications and source records attributed to T Shibamoto.

At least 109 records · Page 6Linked to original sources
PubMed1989

Platelike and globelike inclusion bodies associated with rough endoplasmic reticulum in alveolar type 2 cells of the sheep.

We studied the ultrastructure of alveolar type 2 cells of sheep. The inclusion bodies of rodlike structures or cisternal bodies derived from the endoplasmic reticulum were found in 13.6 +/- 7.0% (+/- SD) of type 2 cells. The length of the rodlike structure varied, the longest being 2.4 microns; but the width was usually 0.1 micron. Rod-like structures were usually straight and arranged in parallel stacks. An electron-dense line ran longitudinally at the center of the rodlike structures. Serial ultrathin sections revealed that the rodlike structures did not seem to be three-dimensionally rod-shaped structures but were actually plate-disc or cup-shaped, and the piled-up rodlike structures were connected to each other at their ends. This rodlike structure in type 2 cells of sheep seems rather to be a platelike inclusion body. The cisternal body, on the other hand, was circular or oval-shaped cisternae containing aggregated electron-dense materials distributed in an arabesque or speckled pattern. Serial ultrathin section examination revealed the cisternal body to be three-dimensionally a globe. Some plate bodies were arranged near the cisternal body, suggesting the transformation from the latter to the former. The functional significance of these findings has not yet been elucidated.

Animals↗
PubMed1989

Relative metabolism of quinones to semiquinone radicals in xanthine oxidase system.

Rates of enzymatic single-electron reduction of some myotoxic quinones to semiquinone metabolites in an in vitro xanthine oxidase/hypoxanthine/catalase system varied widely. Naphthoquinones, especially juglone, were found to undergo rapid single-electron reduction. Benzoquinones and benzoquinoneimines, as well as phenanthrene-9,10-quinone, benzo[a]pyrene-3,6-quinone, and diethylstilbestrolquinone, were also actively reduced. The anthraquinones danthron, doxorubicin and emodin were poorly metabolized in this system. N-Acetylcysteine inhibited quinone-stimulated cytochrome C reduction at high concentrations. The results of this study are discussed with respect to cytotoxicity and mutagenicity of selected quinones.

1-Propanol↗
PubMed1989

Gas chromatographic analysis of free and bound malonaldehyde in rat liver homogenates.

A gas chromatographic method for the measurement of free and bound malonaldehyde (MA) in rat liver homogenate was developed to investigate biological damage caused by lipid peroxidation. Free MA was derivatized 1-methylpyrazole (1-MP), which was subsequently analyzed by capillary gas chromatography (GC). Bound forms of MA were determined by first hydrolyzing samples in acetic acid, then measuring the free MA as 1-MP. Bound MA in rat liver was released within 15 min by acid hydrolysis. A slight increase in bound MA levels in rat liver was observed 1 hr after CCl4 treatment, with bound MA then returning to control levels. Free MA levels and thiobarbituric acid assay (TBA) values did not show appreciable changes over a 24-hr period after CCl4 administration. However, the TBA values were approximately ten times the MA values in most samples.

Animals↗
PubMed1989

Effects of Cassia obtusifolia (sicklepod) extracts and anthraquinones on muscle mitochondrial function.

Naturally occurring quinones and quinone-containing extracts of seeds of the toxic plant Cassia obtusifolia (sicklepod) affected muscle mitochondrial function. Aqueous suspensions and organic extracts of C. obtusifolia seeds slightly elevated plasma creatine kinase levels of Sprague-Dawley rats. These extracts were analyzed by fused silica capillary gas chromatography and found to contain nine anthraquinones and three anthrones. Urinary metabolites primarily consisted of beta-glucuronide conjugates of the anthraquinones. The three anthrones or conjugate analogues were not present in the urine in detectable amounts. Emodin, doxorubicin and organic extracts of C. obtusifolia inhibited NADH:cytochrome c oxidoreductase activity of bovine heart mitochondrial particles and NADH:CoQ oxidoreductase activity of porcine heart mitochondrial NADH dehydrogenase, whereas juglone was stimulatory. Relative quinone metabolism correlated with semiquinone formation rate and with redox potential. A protective effect of coenzyme Q against enzyme inhibition by anthraquinones was also observed.

Animals↗
PubMed1989

Metabolism of N-nitroso-1,3-thiazolidine in the rat.

[2-14C]N-nitroso-1,3-thiazolidine (125 mg/kg body weight) administered by gavage to rats was excreted mostly (81% of the dose) in the urine with a smaller amount (7%) in respired air. The major metabolite in the urine (77.2%) was 2-hydroxy-1,3-thiazolidine and minor quantities of the isomers 4- and 5-hydroxy-1,3-thiazolidine were also detected. The presence of hydroxy-1,3-thiazolidine, determined using mass spectrometry and high-performance liquid chromatography, indicated that alpha-hydroxylation and denitrosation are major metabolic pathways of N-nitroso-1,3-thiazolidine. Analysis of the non-acidic urine extract with gas chromatography-mass spectrometry (GC-MS) using untreated on-column injection and heated split injection gave differing results. Compounds detected using the latter technique may have been artefacts formed by pyrolysis in the heated injection port. Analysis of the metabolites by direct probe mass spectrometry (unheated) and Fourier transform infra-red spectroscopy supported the results seen with on-column GC-MS.

Animals↗
PubMed1989

Gas chromatographic determination of malonaldehyde formed by lipid peroxidation.

Gas chromatographic (GC) methods for the determination of malonaldehyde (MA) all require formation of a stable derivative of MA since free MA is not suitable for direct GC analysis. Most reported GC methods give a total measure of free MA and its bound forms because their assay conditions are sufficient to hydrolyze or decompose bound MA during sample preparation. In this paper, GC methods that provide a measure of total MA (free plus bound) are reviewed. A recently developed capillary GC method that allows determination of free MA apart from other forms is also discussed. The method involves derivatization of MA to N-methylpyrazole under milder reaction conditions than with other GC methods. The method represents an advantage over existing techniques for free MA determination because capillary GC offers the highest efficiency of separation among chromatographic methods thus allowing a more specific and accurate measure of MA.

Chromatography, Gas↗
PubMed1989

Production of malonaldehyde from squalene, a major skin surface lipid, during UV-irradiation.

Malonaldehyde (MA), a product of lipid peroxidation, is known to have a number of toxicological effects. Among skin surface components, squalene has been suggested as a significant source of MA following UV exposure. Irradiation of squalene coated on the inside surface of glass tubes served as a simple model to examine skin surface photochemistry. Malonaldehyde produced during UV-irradiation was reacted with methyl hydrazine to form N-methylpyrazole, which was then measured by gas chromatographic analysis. Ultraviolet A-irradiation produced low levels of MA from squalene, with a maximum of 1.0 nmol MA/mumol squalene near 6 h. Malonaldehyde production varied with the energy of irradiation, with levels of 176 nmol/mg squalene and 9 nmol/mg squalene produced after 3 h of irradiation with UVB and UVA, respectively. The thiobarbituric acid (TBA) assay for lipid peroxidation showed large overestimations of MA levels under all irradiation conditions tested. The TBA assay predicted the highest levels of MA with UVC but we did not detect any MA with our assay.

Chromatography, Gas↗
PubMed1989

Genotoxicity testing of Maillard reaction products.

Since the development of short-term genotoxicity tests such as the Ames assay, the mutagenicity of Maillard reaction products has been tested extensively. Some products have exhibited strong activity. For example, one of the earliest studies demonstrated some mutagenic activity in a dichloromethane extract of a D-glucose/ammonia Maillard model system. Many researchers have attempted to pinpoint the principal chemical(s) of mutagenicity of the Maillard products using various sugar-amino acid browning model systems over last two decades. However, no mutagenic individual Maillard product has been isolated and identified. Nitrite has been also used as a reactant in browning reaction model systems, primarily to investigate the formation of potentially mutagenic or carcinogenic N-nitroso compounds. Recently some potent mutagens isolated from pyrolyzed amino acids or proteins have begun to receive attention as Maillard reaction products.

Amino Acids↗
PubMed1989

[Diagnosis of paraaortic and pelvic lymph node metastasis by ultrasound guided percutaneous fine needle aspiration biopsy (FNAB)].

Ultrasonography (US) was performed in patients with gynecologic malignancies to detect paraaortic and pelvic lymphadenopathy. US of paraaortic lymph nodes was performed in 32 patients. Of the 32 patients 17 had lymphadenopathy, and ultrasound-guided percutaneous fine needle aspiration biopsies (FNAB) were therefore performed in 16 of these 17 cases. Of these 16 patients, 11 were positive and 5 were negative FNAB. US of pelvic lymph nodes was performed in 68 patients. Of the 68 patients 14 had lymphadenopathy, and FNAB were performed in 8 of these. All 14 of these FNABs were positive. There were no major complications from due to FNAB. It is therefore concluded that ultrasound-guided percutaneous FNAB is very useful in detecting metastatic lymph nodes of gynecologic malignancies.

Aorta, Abdominal↗
PubMed1989

Irregular nocturnal breathing patterns high altitude in subjects susceptible to high-altitude pulmonary edema (HAPE): a preliminary study.

We studied nocturnal breathing patterns and symptoms of acute mountain sickness (AMS) during trekking in the Japanese Alps (altitude: 2,760-2,920 m) for 4 d in five subjects susceptible to high-altitude pulmonary edema (HAPE-S-S) and five control volunteers. Breathing patterns were evaluated with the impedance plethysmograph, and symptoms of AMS were evaluated by the environmental symptoms questionnaire-III score for AMS of cerebral type (AMS-C score). In both groups, the percentage of time with periodic breathing significantly increased at high altitude and the percentage in controls was significantly higher than in HAPE-S-S on the second night. In four HAPE-S-S, other disordered breathing patterns, termed "irregular breathing," were observed frequently by night at high altitude. Irregular breathing patterns were characterized by irregularly repeated oscillatory or nonoscillatory clusters of breaths with augmented tidal volume, followed by expiratory pause, apnea, or hypoventilation of various durations. All controls did not show significant changes in AMS-C score, but four HAPE-S-S showed the increase in AMS-C score on the next morning after frequent irregular nocturnal breathing. There was significant correlation between the percentage of time with irregular nocturnal breathing and AMS-C score on the next morning. These results suggest that HAPE-S-S are prone to irregular nocturnal breathing patterns at high altitude, which is associated with the development of AMS, but it was not possible to determine whether these abnormal breathing patterns are a cause or an effect of AMS.

Adult↗
PubMed1988

Analysis of free malondialdehyde in photoirradiated corn oil and beef fat via a pyrazole derivative.

Malondialdehyde (MA) formed in linolenic acid, linoleic acid, corn oil and beef fat upon photoirradiation was determined by gas chromatography (GC). The MA produced was reacted with methylhydrazine to give 1-methylpyrazole and was subsequently analyzed on a GC equipped with a nitrogen-phosphorus specific detector and a fused silica capillary column. MA values determined by this method correspond to free or unbound MA levels. Linolenic and linoleic acids produced 867 micrograms MA/g and 106 micrograms MA/g, respectively. Oleic and stearic acids did not produce detectable levels of MA upon photoirradiation. Amounts of MA produced after eight hour irradiations of corn oil and beef fat were 56.24 micrograms/g and 25.01 micrograms/g, respectively. Some photoreaction products in irradiated corn oil also were identified as methylhydrazine derivatives.

Calibration↗
PubMed1988

Effects of hypobaria on lung fluid balance in awake sheep.

Effects of hypobaria on lung fluid balance were studied in five awake sheep with chronic lung lymph fistulas using a decompression chamber. Each sheep was exposed to three conditions of 6,600-m-simulated high altitude in random order as follows: 1) 6,600-m-simulated hypoxic hypobaria (barometric pressure 326 Torr, 21% inspired O2 fraction), 2) 6,600-m-simulated normoxic hypobaria (barometric pressure 326 Torr, 65% inspired O2 fraction), and 3) 6,600-m-simulated normoxic hypobaria (barometric pressure 326 Torr, 65% inspired O2 fraction) after pretreatment with a 2-h pure O2 inhalation (i.e., denitrogenation) to allow elimination of dissolved gases, especially N2, from the blood and tissues. We observed that under both hypoxic hypobaria and normoxic hypobaria, lung lymph flow (Qlym) significantly increased from the base-line values of 6.4 +/- 0.3 to 13.0 +/- 1.0 ml/h and 6.0 +/- 0.2 to 9.4 +/- 0.3 ml/h, respectively (P less than 0.05) and that the lymph-to-plasma protein concentration ratio remained unchanged. Moreover, pretreatment with a 2-h denitrogenation inhibited the increase in Qlym. These results suggest that rapid exposure to hypobaria causes an increase in pulmonary vascular permeability and that intravascular air bubble formation may account for this permeability change.

Altitude↗
PubMed1988

Role of barometric pressure in pulmonary fluid balance and oxygen transport.

To examine the role of barometric pressure in high-altitude pulmonary edema, we randomly exposed five unanesthetized chronically instrumented sheep with lung lymph fistulas in a decompression chamber to each of three separate conditions: hypobaric hypoxia, normobaric hypoxia, and normoxic hypobaria. A combination of slow decompression and/or simultaneous adjustment of inspired PO2 provided three successive stages of simulated altitudes of 2,600, 4,600, and 6,600 m during which hemodynamics and lymph flow were monitored. Under both hypoxic conditions we noted significant and equivalent elevations in pulmonary arterial pressure (Ppa), cardiac output, and heart rate, with left atrial and systemic pressures remaining fairly constant. Normoxic hypobaria was also accompanied by a smaller but significant rise in Ppa. Lymph flow increased to a highly significant maximum of 73% above base line, accompanied by a slight but significant decrease in lung lymph-to-plasma protein ratio, only under conditions of combined hypobaric hypoxia but not under equivalent degrees of alveolar hypoxia or hypobaria alone. Arterial hypoxemia was noted under all three conditions, with arterial PO2 being uniformly lower under hypobaric conditions than when identical amounts of inspired PO2 were delivered at normal atmospheric pressure. We therefore hypothesize that alveolar pressure significantly alters the Starling forces governing transcapillary fluid flux in the lung and may affect the alveolar-arterial gradient for O2 as well.

Altitude↗
PubMed1988

Effects of methylprednisolone on acute lung paraquat toxicity in sheep.

Infused into sheep, paraquat causes increased flow of protein-rich lung lymph, increased prostanoid production, and neutrophil accumulation in the lung. The effects of high-dose methylprednisolone on the response to paraquat infusion were studied in awake sheep with chronic lung lymph fistulas. Seven sheep were infused with paraquat (30 mg/kg) alone. Six sheep received methylprednisolone (1.0 g plus 0.5 g/h intravenously), beginning 30 min before paraquat (pretreatment), and 5 received methylprednisolone, beginning 4 h after paraquat (post-treatment). Neutrophil accumulation in the lung was measured in biopsy tissue taken at baseline and at postmortem. Methylprednisolone pretreatment significantly prevented the increase in lung lymph flow (paraquat, from 4.4 +/- 0.3 to 11.1 +/- 0.8 ml/h, p less than 0.05; pretreatment, from 4.8 +/- 0.9 to 3.7 +/- 0.3, NS), and the increase in lymph-to-plasma protein concentration ratio (paraquat, from 0.69 +/- 0.02 to 0.80 +/- 0.02, p less than 0.05; pretreatment, from 0.66 +/- 0.06 to 0.60 +/- 0.02, NS) during 8 h after paraquat infusion. Treatment with methylprednisolone after paraquat also reduced the changes in lung lymph flow and protein clearance. Methylprednisolone prior to paraquat significantly inhibited accumulation of 6-keto-PGF1 alpha in lymph and plasma, but did not significantly inhibit accumulation of TxB2 in lymph or plasma. The number of neutrophils in the paraquat lungs was 3 to 4 times that in the control lungs, with or without methylprednisolone. Methylprednisolone pretreatment prolonged the survival time, but did not prevent death within 48 h after paraquat infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

6-Ketoprostaglandin F1 alpha↗
PubMed1988

The increased sympathoadrenal activity in patients with high altitude pulmonary edema is centrally mediated.

To assess the role of catecholamines in the pathogenesis of high altitude pulmonary edema (HAPE), 24-hour urinary catecholamine excretions and plasma catecholamine concentrations were measured. We also performed brain computed tomography (CT) in the same 8 serial patients with HAPE. 24-hour urinary norepinephrine excretion showed a statistically high value on admission compared with that after recovery (396.9 +/- 92.9 micrograms/24 hr, decreasing to 93.0 +/- 31.1 micrograms/24 hr, mean +/- S.E., p less than 0.01). 24-hour urinary epinephrine excretion on admission was also remarkably high, and returned later normal (62.9 +/- 25.8 micrograms/24 hr, decreasing to 12.7 +/- 4.2 micrograms/24 hr, p less than 0.05). Plasma norepinephrine concentration was also high, but returned to normal (0.260 +/- 0.073 ng/ml, to 0.11 +/- 0.043 ng/ml) by the time of discharge. Brain CT scans revealed diffuse low density of the entire cerebrum, small ventricles, disappearance of sulci, and small cistern, suggesting cerebral edema. These findings may suggest that the heightened sympathoadrenal activity that occurred in the patients concomitant with cerebral edema was related to the high altitude illness rather than to simple exposure to high altitude.

Adrenal Glands↗
PubMed1988

[Tissue distribution of beta-lactam antibiotics, cefotiam and cefmenoxime in the lungs of sheep].

The present study was performed to investigate the distribution of beta-lactam antibiotics, cefotiam (CTM) and cefmenoxime (CMX) in pulmonary tissue of sheep. The animals were prepared to form chronic lung-lymph fistula for the collection of lung lymph. CTM and CMX were administered bolus-intravenously at doses of 20 mg/kg and 40 mg/kg, respectively, and serum and lymph levels of each drug were measured by bioassay method. Antibiotic levels of serum or lymph increased to a peak within 15 minutes after injection and then decreased rapidly. Measurable concentrations persisted for 240 minutes after the injection. Ratios of lung lymph to serum concentrations of CTM and CMX within 1 hour after the injection ranged 0.7 to 1.3, and 0.9 to 1.3, respectively. In addition, CMX levels in serum, lung lymph and tissues of both right and left lung were compared in anesthetized sheep to which CMX 50 mg/kg was given. Ratios of lung lymph and tissue concentrations of CMX in right and left lung to serum concentration were 0.76, 0.14 and 0.13, respectively. These results indicate that CTM and CMX were well distributed in interstitial fluid (lung lymph), and the levels of CMX in tissues of both right and left lung were markedly lower than those of lung lymph.

Animals↗