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Biomedical subjects

S Kitamura

Publications and source records attributed to S Kitamura.

At least 685 records · Page 38Linked to original sources
PubMed1989

Right upper lobe versus right middle lobe: differentiation with thin-section, high-resolution CT.

A new method was developed to differentiate the upper lobe from the middle lobe of the right lung with thin-section, high-resolution computed tomography. In the upper lobe, a medial subsegmental bronchus of an anterior segmental bronchus is always located lateral to the corresponding artery. In the middle lobe, a medial subsegmental bronchus of a lateral segmental bronchus and a superior and inferior subsegmental bronchus of a medial segmental bronchus are always located medial to the corresponding artery. In other words, the anatomic relationship between the subsegmental bronchi and the corresponding pulmonary arteries in the upper lobe is opposite to that in the middle lobe. One hundred seventeen cases, including 54 cases of lobar volume loss, were reviewed with this method, and in each case it was possible to differentiate the upper lobe from the middle lobe without the contiguous section analysis.

Adult↗
PubMed1989

Effects of smoking on the synthesis of leukotriene B4 by rat alveolar macrophages.

Leukotriene B4 (LTB4) is a potent chemotactic factor for polymorphonuclear leukocytes. It was reported recently that pulmonary macrophages from some mammalian species synthesize and release LTB4. Laviolette et al. reported the decrease of LTB4 synthesis in smokers' alveolar macrophages (AM). In this paper, we report the chronic effects of passive smoking on the production of LTB4 by rat AM. Some rats inhaled tobacco smoke and some inhaled smoke which did not contain nicotine. LTB4 production from AM from these rats was compared. In the tobacco-smoking group (n = 12), LTB4 production was 8.0 +/- 2.4 ng/10(6) cells. This value was significantly lower than in the nonsmoking (NS) group (n = 12; 16.5 +/- 4.5 ng/10(6) cells; p less than 0.01) and in the non-nicotinized cigarette smoking (NNCS) group (n = 8; 18.5 +/- 3.5 ng/10(6) cells; p less than 0.01). There were no significant differences between the NS and the NNCS group. These data may suggest that chronic inhalation of nicotine in tobacco smoke decreases LTB4 production activity of rat AM. The precise mechanism of decreased synthesis of LTB4 is not clear but it may have some immunological effects on the lung.

Animals↗
PubMed1989

Spontaneous tumors in F-344/Jcl rats.

The age-related incidence of spontaneously occurring neoplastic and non-neoplastic lesions in untreated F-344/Jcl rats, used as controls in carcinogenicity testing, were studied from the histological examination of tissues from 469 males and 354 females. The incidence of spontaneous tumors was 83.2% in the males and 71.2% in the females. The most common neoplasms were leukemia (males: 24.3%, females: 24.0%), pituitary adenoma (males: 16.0%, females: 45.2%), pheochromocytoma (males: 14.7%, females: 7.3%), testicular interstitial cell tumor (males: 79.1%), and uterine endometrial stromal polyp(females: 16.4%). The incidence of other tumors of almost all the organs and/or tissues was low. Non-neoplastic lesions generally increased with advancing age of the animals.

Age Factors↗
PubMed1989

Metabolism of drugs in the eye. Menadione-dependent reduction of tertiary amine N-oxide by preparations from bovine ocular tissues.

As described previously, the microsomes and cytosol from bovine ciliary body exhibited a significant reductase activity toward tertiary amine N-oxide such as imipramine N-oxide when supplemented with menadione. In the present study, the menadione-dependent N-oxide reduction was further examined with preparations of bovine ocular tissues. The reduction of imipramine N-oxide occurred much more significantly when the microsomes and cytosols from bovine ciliary body were supplemented with both menadione and NAD(P)H, compared with menadione alone. The cytosolic menadione-dependent reduction, but not the microsomal one, was markedly inhibited by dicumarol, suggesting the involvement of DT-diaphorase in the reaction. Localization of the menadione-dependent N-oxide reductase activity in bovine ocular tissues indicated that the highest activity resided in the ciliary body, followed by retinal pigment epithelium-choroid, iris, retina and cornea. When the cytosol from bovine ciliary body was fractionated with ammonium sulfate, the distribution of the menadione-dependent N-oxide reductase activity in the resultant fractions was parallel, but roughly, to that of DT-diaphorase activity, supporting the assumption that the flavoenzyme was involved in the cytosolic menadione-dependent N-oxide reduction. We proposed a new mechanism for the metabolic reduction of tertiary amine N-oxide in the eye: Menadione is reduced to the corresponding diol by quinone-reducing enzymes and then tertiary amine N-oxide is reduced by the diol to the corresponding amine nonenzymatically.

Animals↗
PubMed1989

Purification of aldehyde oxidase from bovine ciliary body.

Ocular aldehyde oxidase was purified for the first time from bovine ciliary body cytosol by ammonium sulfate fractionation and successive HPLC using DEAE anion-exchange and hydroxyapatite columns. The purified enzyme was homogeneous by the criterion of sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The molecular weight of the enzyme was estimated to be about 150,000 by electrophoresis and to be about 300,000 by gel filtration HPLC on a TSK gel G3000SWXL column, indicating that the enzyme consists of two subunits with the same molecular weight. On the other hand, nicotinamide N-oxide reductase activity was associated with aldehyde oxidase activity throughout the purification steps of the latter enzyme. This fact indicated that nicotinamide N-oxide reductase activity of the ciliary body cytosol is due to aldehyde oxidase present in the tissue preparation.

Aldehyde Oxidase↗
PubMed1989

[Cerebral hemodynamics in multiple cerebral infarction with or without dementia].

Cerebral blood flow and metabolism in 25 patients with multiple cerebral infarcts (14 with dementia) and 5 healthy age-matched controls were measured to investigate the difference in cerebral blood low (CBF) and cerebral oxygen consumption (CMRO2) between patients with dementia and patients without dementia. None of the patients had any lesions in the cortex, but all had multiple lesions in the basal ganglionic region, and in the white matter, according to CT images. CBF, CMRO2 and oxygen extraction fraction were measured by positron emission tomography (PET) using the 15O2, C15O2 steady state inhalational technique. In patients with multiple cerebral infarcts the absolute values of CBF and CMRO2 were decreased significantly from normal control values, and there was no significant difference in the absolute values of CBF and CMRO2 between patients with dementia and patients without dementia. In most patients with dementia, relative values (regional value/mean cortical value) of CBF and CMRO2 decreased in the frontal and the parietal cortex. Four patients had repeated PET studies. In two of them, decrease in CMRO2 was preceded by decrease in CBF. These results suggest that dysfunction of frontal cortex and parietal cortex, and chronic ischemia might be related to the occurrence of dementia in patients with multiple cerebral infarcts, which were in the basal ganglia and the white matter.

Aged↗
PubMed1989

[Mechanisms of bronchoconstriction induced by anaphylaxis in sensitized guinea pigs].

Anaphylactic reaction in sensitized guinea pigs is known to induce bronchoconstriction when an adequate amount of antigen is administrated. This phenomenon has been established as a model of bronchial asthma. To evaluate the mechanism of bronchoconstriction in anaphylaxis, we analyzed the change of endobronchial pressure in sensitized guinea pigs. Guinea pigs weighing 300-600 g were actively sensitized by intracutaneously administrated ovalbumin (10 mg). Two weeks later they were anesthetized and mechanically ventilated with a volume type Harvard respirator. Antigen was administrated intravenously and monitoring of endotracheal pressure and systemic blood pressure was performed. Drugs to modify these reactions were administrated intraperitoneally 30 minutes before antigen challenge. In the control group, the endotracheal pressure showed a curve with the first peak between 0.5 and 1.5 minutes after the antigen challenge. When cyclooxygenase inhibitor (indomethacin) was administered before the antigen, the first peak was markedly suppressed. However, the histamine (H1)-receptor blocker did not suppress the first peak. On the other hand when 5-lipoxygenase inhibitor (AA-861) was administered before the antigen, the increase of intratracheal pressure was suppressed between 2 and 4 minutes after the antigen challenge. The above results may suggest that the first peak of intratracheal pressure derives from bronchoconstriction caused by prostaglandins or thromboxanes, and that the increase of intratracheal pressure at between 2 and 4 minutes derives from bronchoconstriction caused by leukotrienes.

Anaphylaxis↗
PubMed1989

11,12-leukotriene A4: synthesis and metabolism.

11(S),12(S)-oxido-5Z,7E,9E,14Z-eicosatetraenoic acid (11,12-LTA4) was chemically synthesized from 12-hydroperoxy-eicosatetraenoic acid (12-HPETE). 11,12-LTA4 methyl ester was nonenzymically hydrolyzed to at least four products. These products were identified to be epimers of 5,12(S)-dihydroxy-eicosatetraenoic acid methyl ester (5,12(S)-diHETE-Me) and epimers of 11,12-diHETE-Me. In addition to the above nonenzymic products, 11,12-LTA4 was converted to 11,12-LTC4 by the rat liver glutathione S-transferase, and to an isomer of 11,12-diHETE by homogenates of the guinea pig adrenal gland and liver.

Adrenal Glands↗
PubMed1989

[CT findings of post-pneumonectomy patients].

CT findings following pneumonectomy were studied in 28 cases with lung cancer. A total of 53 CT images were evaluated in 13 right pneumonectomy cases and 15 left pneumonectomy patients. The postpneumonectomy pleural space (PS), thoracic space of the operated site (TS) and the thoracic space of the non-operated site (CTS) were measured at 3 slice levels of the brachiocephalic level, subcarinal level and lower pulmonary vein level, using a digital planimeter. There was no significant difference in the TS/CTS ratio, between the right pneumonectomy group and the left pneumonectomy group, but the PS/TS ratio in the left pneumonectomy group was smaller than that in the right pneumonectomy group (p less than 0.01). The PS/TS ratio in both groups and the TS/CTS ratio in the right pneumonectomy group were decreased with time. In the left pneumonectomy group, the TS/CTS ratio was greater in the median sternotomy group that of the posterolateral thoracotomy group (p less than 0.01). Residual pleural effusion was accompanied with a thin circulating lesion along the outer surface. This lesion had been reported as thickening of the parietal pleura, but it could be detected in the case of panpleuropneumonectomized state. Additionally, in some cases, the parietal pleural imaging could be separated from the circulating lesion. So, this structure was thought to be mainly composed of organized effusion. CT images could detect some parts of the episodes in post operated thorax, because of the lack of the information with the sagittal direction. However, the recognition of the common changes and images on CT after the operation might be helpful for the follow-up of the patients.

Adult↗
PubMed1989

[Coronary artery bypass surgery with internal mammary artery grafts: clinical and angiographic results].

We report clinical and angiographic results of coronary artery bypass grafting (CABG) surgery in 307 patients. IMA grafts can be utilized in the wide ranges of patient ages and/or coronary lesions including left main trunk disease, and have good adaptive capability to coronary flow demand with very low probability of atherosclerotic changes. Postoperative (5.2 +/- 4.4 months) patency rates for IMA grafts and SVG were 96% and 86%, respectively; a significant difference (p less than 0.001). From the benefits of this graft, the use of IMA has become a routine procedure in our CABG surgery and the rate of multiple bypasses with IMA grafts has increased recently. The late cardiac events have significantly (p less than 0.05) decreased in patients with the IMA graft than in those without it. We believe that the use of IMA has improved the quality of CABG in Japanese patients and this operative modality can bring better late results than multivessel PTCA.

Adolescent↗
PubMed1989

[Treatment of mediastinal infection following cardiac surgery by continuous closed irrigation with povidone-iodine in early infancy].

Two patients aged 2 months and 9 days with postoperative mediastinal infection were treated by continuous closed irrigation with 0.5% povidone-iodine solution. Satisfactory eradication was achieved in both two patients. Although serum iodine level was elevated as high as 7,610 micrograms/dl in the neonatal patient, no disturbances of the thyroid function and the acid-base balance were seen. The usefulness of continuous closed irrigation in the neonatal or infantile period was suggested.

Cardiac Surgical Procedures↗
PubMed1989

[Effects of thromboxane A2 synthetase inhibitor, DP-1904 on the action of vasoactive substances in guinea pig trachea and lung tissue strips].

Thromboxane A2 (TxA2) is a potent platelet aggregator and vascular or bronchial constrictor. DP-1904, a newly synthesized imidazol TxA2 synthetase inhibitor, is a potent and long-acting agent. The present investigation was conducted to explore the effect of DP-1904 on the contractile or relaxing responses in guinea pig trachea and lung tissue strips induced by various vasoactive substances. Fourteen guinea pigs, weighing 300-350 g, were sacrificed. Trachea and lungs were removed, cut spirally, set up in bioassay glass jackets and superfused with Krebs-Henseleit solution at 37 degrees C, saturated with oxygen and carbon dioxide. Contraction of tissues was detected by an isotonic transducer and displayed on a polyrecorder. Arachidonic acid-induced relaxing responses in guinea pig trachea strips were attenuated significantly by the continuous infusion of DP-1904 in a dose-dependent fashion. Arachidonic acid-induced contractile responses in guinea pig lung strips were attenuated significantly by the continuous infusion of DP-1904, dose-dependently. Acetylcholine-, histamine- and prostaglandin F2 alpha-induced contractile responses in guinea pig lung and trachea strips were attenuated significantly by the continuous infusion of DP-1904, dose-dependently. The above results suggest that DP-1904 might be a useful therapeutic agent for the treatment of chronic obstructive lung diseases.

Acetylcholine↗