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Biomedical subjects

K Otsuka

Publications and source records attributed to K Otsuka.

At least 271 records · Page 15Linked to original sources
PubMed1990

[Relationship between pulmonary functions and sleep respiratory abnormalities in obstructive sleep apnea syndrome].

Pulmonary function tests were performed in 18 cases of obstructive sleep apnea in supine and sitting positions and the relationship between pulmonary function and polysomnographic data was analyzed. %FRC and PaO2 were reduced in the supine position compared with those in the sitting position. It was suggested that the reduction of PaO2 was mainly caused by the elevation of CC/FRC ratio in supine position. The relationship between pulmonary function data and polysomnographic data were analyzed, and an inverse relationship between %FRC in sitting position and desaturation was observed and also a positive relationship between PaO2 in the supine position mean-nadir SO2 was found. Saw-tooth sign and VE50/VI50 greater than 1 on flow-volume curves were not related to the apnea index and desaturation index. These results indicate that the F-V curve is not useful for the diagnosis of OSA.

Humans↗
PubMed1989

REM sleep and bradyarrhythmia episodes in rats.

The relationship between rapid eye movement (REM) phasic events and bradyarrhythmia was investigated in five male Wistar rats. ECGs, EEGs (frontal cortex and dorsal hippocampus), and electrooculograms were monitored continuously for 6 days. Sleep states were classified as alertness, slow-wave sleep, or paradoxical sleep, and the frequency of the REM burst was measured to evaluate the REM density. Bradyarrhythmias, such as SA block or AV block, were observed in each rat and were divided into two groups: group A, bradyarrhythmias with a duration greater than 5 sec; and group B, duration less than 5 sec. For a period of 33 days, the five rats showed alertness, slow-wave sleep, and paradoxical sleep 6,481, 6,483, and 1,523 times; bradyarrhythmia incidents in each sleep stage were 0.35%, 0.03%, and 22.4%, respectively. The incidence of bradyarrhythmia episodes increased with REM density, and 78.5% of the episodes appeared related to the REM bursts. The latency between the REM bursts and bradyarrhythmia was as follows: type A bradyarrhythmias, 2.17 +/- 0.41 sec; type B, 3.78 +/- 0.63 sec. These results suggest close association of bradyarrhythmia occurrence with REM phasic events.

Animals↗
PubMed1989

Cardiotonic agents. 1-Methyl-7-(4-pyridyl)-5,6,7,8-tetrahydro-3 (2H)-isoquinolinones and related compounds. Synthesis and activity.

A series of 1-methyl-7-(4-pyridyl)-5,6,7,8-tetrahydro-3(2H)-isoquinolinones and related compounds were synthesized and evaluated for positive inotropic activity. Most members of this series exerted a dose-dependent increase in myocardial contractility in the dog acute heart failure model, whereas they caused only slight changes in heart rate and blood pressure. Several derivatives, especially those with cyano, acetyl, and ethyl substituents at the 4-position, were more potent than milrinone, which was used as a reference. 4-Acetyl-1-methyl-7-(4-pyridyl)-5,6,7,8-tetrahydro-3(2H)-isoquinolinone (MS-857) is one of the most potent positive inotropic agents in this series.

Animals↗
PubMed1989

Application of Namalva interferon-alpha monoclonal antibodies for purification and enzyme immunoassay of interferon-alpha.

Namalva (or Namalwa) interferon (IFN)-alpha was partially purified using a combination of conventional methods and modified acid-ethanol extraction. Four mouse monoclonal antibodies against Namalva IFN-alpha were prepared by hybridoma technology after immunization with Namalva IFN-alpha thus purified. Three of these monoclonal antibodies recognized the same or a similar epitope on Namalva IFN-alpha. One of these antibodies was paired with the fourth recognizing a different epitope and used respectively as enzyme-conjugated antibody and solid-phase antibody in our one step enzyme immunoassay (EIA) for IFN-alpha. This assay is simple and was able to detect as little as 5 pg of IFN-alpha in 100 microliters of sample in the short time of 5 hr. There was a good correlation between the EIA and bioassay. The use of one of the monoclonal antibodies as an immunoadsorbant to purify Namalva IFN-alpha is also described.

Animals↗
PubMed1989

The first record of a confirmed human case of Gnathostoma doloresi infection.

The first case of Gnathostoma doloresi infection in a human was found in Miyazaki Prefecture, Japan. A whole length of the parasite was dissected out from biopsied skin and was identified as the third-stage larva of G. doloresi based on the morphological characteristics of the hooklets of the head bulb and also on the number of nuclei in the intestinal epithelial cells of the parasite.

Animals↗
PubMed1988

Specific binding of peanut agglutinin and soybean agglutinin to chondroitinase ABC-digested cartilage proteoglycans: histochemical, ultrastructural cytochemical, and biochemical characterization.

The binding of peanut agglutinin (PNA) and soybean agglutinin (SBA) to cartilage proteoglycans was investigated by histochemical, ultrastructural cytochemical, and biochemical methods. Following aldehyde fixation, specimens of rat epiphyseal cartilage were examined by horseradish peroxidase-labelled lectin cytochemistry with and without prior digestion in chondroitinase ABC. At the light microscope level neither PNA nor SBA exhibited any affinity for cartilage matrix, but became strongly bound following chondroitinase treatment. Similarly, at the ultrastructural level, extracellular matrix granules, presumed to be proteoglycan monomer(s), lacked PNA affinity in undigested specimens, and stained very weakly with SBA. Both PNA and SBA weakly to moderately stained the trans cisternae of the Golgi-flattened cisternae in chondrocytes. The chondrocyte plasmalemma lacked PNA staining, but reacted weakly with SBA. Following chondroitinase digestion, PNA and SBA stained matrix granules, and the cell surface of chondrocytes intensely, whereas the Golgi trans cisternae, the Golgi-derived vacuoles, and multivesicular bodies demonstrated weak to moderate reactivity. Proteoglycan aggregates purified from rat chondrosarcoma and bovine nasal cartilage bound PNA and SBA avidly after digestion with chondroitinase. Undigested proteoglycans lacked affinity for PNA and reacted very weakly with SBA. These results indicate that both PNA and SBA specifically react with chondroitinase-modified oligosaccharide(s) bound to core proteins of cartilage proteoglycans. This provided a specific histochemical and ultrastructural cytochemical procedure for localizing chondroitin sulphate-containing proteoglycans.

Animals↗
PubMed1988

Response of medial preoptic/anterior hypothalamic neurones to ventrolateral medulla stimulation and its attenuation by adrenoceptor antagonists.

Extracellular single-unit recordings were made from medial preoptic/anterior hypothalamic (MPOAH) neurones in urethane-anaesthetized female rats, and the responses of these neurones to electrical stimulation of the ventrolateral medulla (VLM) were investigated. Of 189 neurones tested, 20% were excited and 21% were inhibited following VLM stimulation. The latency of inhibitory responses showed a normal distribution and the mean latency was 47 ms, whereas the latency of excitatory responses showed a bimodal distribution with peaks in the ranges of 0-10 ms and 40-50 ms, respectively. Excitatory responses with latencies greater than 15 ms and inhibitory responses were significantly attenuated by intravenous injections of the alpha-adrenoceptor antagonist phenoxybenzamine but not the beta-adrenoceptor antagonist propranolol. In the light of these observations and the known anatomical and electrophysiological findings, it is suggested that A1 noradrenergic and/or C1 adrenergic inputs from the VLM to MPOAH neurones are, at least in part, mediated by alpha-adrenoceptors.

Animals↗
PubMed1988

Influence of microinjection of corticosterone into ventromedial hypothalamus on hepatic acetate metabolism in rabbits.

Corticosterone was injected into the ventromedial hypothalamus (VMH) of rabbits, and changes in hepatic acetate metabolism were studied. The microinjection of corticosterone with seasame oil into the VMH of intact rabbits increased the rates of 14C transfer from 14C-1-acetate into CO2, glucose, ketone bodies, triglyceride, free cholesterol, free fatty acids and phospholipids but decreased those of 14C transfer into cholesterol ester. However, corticosterone injected into the VMH of rabbits with VMH lesions or the parietal cortex of intact rabbits was without effect on the hepatic acetate metabolism. From these results it might be suggested that the VMH is an integral part of the corticosterone-sensitive brain regulator system in the hepatic acetate metabolism.

Acetates↗
PubMed1988

Electrophysiology of neurones projections from the rat A1 noradrenergic region to the medial preoptic/anterior hypothalamic area: lack of effect of the oestrous cycle on their excitability.

The neuronal excitability of presumed A1 noradrenergic neurones in the ventrolateral medulla (VLM) which directly project to the medial preoptic/anterior hypothalamic area was analysed in pro-oestrous and metoestrous female rats under urethane anaesthesia. No significant difference was detected between the two groups for the antidromic activation threshold, absolute refractory period, frequency of successful antidromic propagation into the somatodendritic membrane, duration of post-stimulus inhibition, or spontaneous firing rate of these neurones. These results do not support the idea that the neuronal somata of A1 noradrenergic neurones in the VLM show a pro-oestrous increase in excitability during the oestrous cycle, although limitations of the methodology employed do not completely rule out this possibility.

Animals↗
PubMed1988

Immunobiological activities of a porin fraction isolated from Fusobacterium nucleatum ATCC 10953.

From Fusobacterium nucleatum ATCC 10953 cell envelope fraction whose inner membranes had been removed by treatment with sodium N-lauroyl sarcosinate, an outer membrane protein (37,000 Mr in a native state) was prepared by extraction with lithium dodecyl sulfate. The protein thus obtained showed distinct porin activity, namely, the ability to form hydrophilic diffusion pores by incorporation into the artificial liposome membrane. The porin fraction exhibited strong immunobiological activities in the in vitro assays: B-cell mitogenicity and polyclonal B-cell activation on murine splenocytes, stimulatory effects on guinea pig peritoneal macrophages, and enhancement of the migration of human blood monocytes. The porin fraction also exhibited immunoadjuvant activity to increase the antibody production against sheep erythrocytes in the spleen of mice that were immunized by sheep erythrocytes with porin. Although chemical analyses revealed that the test porin fraction contained a considerable amount of lipopolysaccharide (LPS) (around 12% of the fraction), the studies with LPS-nonresponding C3H/HeJ mice and on the inhibitory effects of polymyxin B strongly suggest that most of the above bioactivities are due to porin protein itself, not to coexistent LPS in the porin fraction.

Adjuvants, Immunologic↗