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Biomedical subjects

K Azumi

Publications and source records attributed to K Azumi.

At least 37 records · Page 2Linked to original sources
PubMed1991

A novel lipopolysaccharide-binding hemagglutinin isolated from hemocytes of the solitary ascidian, Halocynthia roretzi: it can agglutinate bacteria.

A hemagglutinin was isolated from hemocytes of the ascidian, Halocynthia roretzi, by a procedure including extraction and ion-exchange chromatography on CM-cellulose. The molecular weight of the hemagglutinin was estimated to be 120,000 by gel filtration. It was resistant to acid treatment but sensitive to alkali or heat treatment. The hemagglutinating activity was inhibited by heparin, chondroitin sulfate, and lipopolysaccharide (LPS), but not by mono- and disaccharides such as N-acetyl-galactosamine, galactose, and melibiose. The hemagglutinin showed binding ability to heparin and LPS, as demonstrated by heparin-Sepharose chromatography and centrifugation experiments, respectively. It was also found that the hemagglutinin can bind to various bacteria such as Escherichia coli, Bacillus subtilis, Vibrio anguillarum, Pseudomonas perfectomarinus, Achromobacter aquamarinus, and Alteromonas putrefaciens, and can agglutinate all of them.

Animals↗
PubMed1991

[Successful repair of subvalvular annular aneurysm of the left ventricle].

A 62-year-old woman was admitted to our hospital due to congestive heart failure. On the chest X-ray film, cardiomegaly and prominent pulmonary congestion were revealed. She became well with bed rest and medication of digitalis and diuretics. Echocardiogram established the diagnosis of severe mitral regurgitation. In addition, cineangiography of the left ventricule showed cystic left ventricular aneurysm which originated from below the posterior mitral annulus. Operation was performed on July 16, 1990. Under cardiopulmonary bypass, we reflected the apex of the LV upwards, but failed to identify the aneurysm. Then, left atrium was opened through Dubost incision. As regards mitral valve structures, there were no abnormal findings except moderate enlargement of it's orifice. After resection of the mitral valve, orifice of the aneurysm (0.5 X 2.0 cm) was recognized, which was closed with the buttressed sutures. Afterwards, MVR was performed with 25 mm Medtronic Hall valve. The patient had a smooth postoperative course without complication.

Female↗
PubMed1990

Inhibitory effect of halocyamine, an antimicrobial substance from ascidian hemocytes, on the growth of fish viruses and marine bacteria.

Halocyamine A, an antimicrobial substance isolated from hemocytes of the solitary ascidian Halocynthia roretzi, inhibited in vitro the growth of fish RNA viruses (infectious hematopoietic necrosis virus and infectious pancreatic necrosis virus). Pretreatment of RNA virus with halocyamine A reduced the infectivity of the virus toward host cells. The growth of marine bacteria, Achromobacter aquamarinus and Pseudomonas perfectomarinus, was also inhibited by halocyamine A but that of Alteromonas putrefaciens and Vibrio anguillarum was not. These results suggest that halocyamine may have a role in the defense mechanisms of H. roretzi against marine viruses and bacteria.

Animals↗
PubMed1990

Halocyamines: novel antimicrobial tetrapeptide-like substances isolated from the hemocytes of the solitary ascidian Halocynthia roretzi.

Two novel antimicrobial tetrapeptide-like substances, halocyamine A and B, were isolated from the solitary ascidian Halocynthia roretzi by a procedure including extraction steps, chromatographies on coarse and fine HP-20 columns, and preparative reversed-phase high-performance liquid chromatography. The structures of halocyamine A and B were determined to be L-histidyl-L-6,7-dihydroxyphenylalanylglycyl-6-bromo-8,9-didehy drotryptamine and L-threonyl-L-6,7-dihydroxyphenylalanyl-L-histidyl-6-bromo-8,9- didehydrotryptamine, respectively, by spectral analyses and degradation studies. Besides antimicrobial activities against several kinds of bacteria and yeasts, both of them showed cytotoxic activities against neuronal cells cultured from rat fetal brain, mouse neuroblastoma N-18 cells, and human hepatoma Hep-G2 cells. They were only detected in the "morula"-like cells, which are of the most abundant cell type among the hemocytes of H. roretzi.

Animals↗
PubMed1987

Filter transient response to EEG waveforms.

The response of two types of linear filters to sinusoidal bursts was calculated to demonstrate how filters can distort EEG waveforms. Results show that the wider the filter bandwidth the less is the distortion, and for a given bandwidth, the higher the filter order the greater the distortion. The response of a linear phase filter was also calculated to demonstrate that this type of filter can also cause waveform distortion, although it is normally less than that caused by Butterworth, Tchebychev and elliptic filters.

Electroencephalography↗
PubMed1982

Characteristics of spindle activity and their use in evaluation of hypnotics.

The spindle activity of 10 healthy male adults, aged 20-24 years, was investigated over 7 consecutive nights. Spindle appearance showed a strikingly distinctive and reproducible pattern for each individual. There was no first-night effect and little night-to-night variation of spindle appearance rate per night. Eight male adults aged between 19 and 24 years were studied in an evaluation of methaqualone and flunitrazepam by an experimental schedule of 17 consecutive nights. Both drugs caused a significant increase of spindle activity expressed as appearance rate. By using spindle activity as a sleep parameter we could investigate in more detail the characteristics of hypnotics.

Adult↗
PubMed1975

REM phase deprivation and schizophrenia II.

Nine schizophrenic patients with active symptomatology were compared with seven patient controls in their response to two nights of rapid eye movement (REM) sleep deprivation. The control subjects demonstrate "normal" increases in total REM and percentage REM time increase on recovery nights compared to base line nights. The schizophrenic subjects differ substantially from the control subjects in both these measurements and show no perceptible change from base line nights on recovery nights. The effects of medication, anxiety, sleep loss, ceiling effects, and intensity change were not considered adequate to account for the above results. However, many questions, such as the specificity of this rebound failure to the schizophrenic patients and the possibility of a sleep disturbance factor operating independently of psychiatric diagnosis, remain to be answered.

Adult↗