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Biomedical subjects

R Suzuki

Publications and source records attributed to R Suzuki.

At least 685 records · Page 38Linked to original sources
PubMed1985

[Experimental study of brain lesions after combined coaxial exposure to high-peaked pulse wave form CO2 and Nd: YAG lasers on the brain].

UNLABELLED: The CO2 laser is useful for cutting and vaporization but not for coagulation and hemostasis. On the contrary, YAG laser is effective for coagulation and hemostasis but not for cutting. The purpose of this study is to examine the effect of the exposure of combined, coaxial CO2 and YAG laser on the animal brain to supplement the advantages and draw-backs of each other. To compare these results, each of non-combined pulse wave form CO2 and YAG lasers was employed separately. MATERIALS AND METHODS: The lasers in this study were pulse wave form CO2 and YAG lasers, employed separately or simultaneously using 130 YZ of Nihon Infrared Industries Company. Japanese white rabbits were anesthetized with pentobarbital. Fronto-parietal burr holes were made, the dura was removed and then Evans blue solution was injected intravenously. The lasers were employed to the cerebral cortex without great vessels using a micromanipulator attached to the operative microscope with a distance of 30 cm. The spot size was 700 mu for CO2 laser and 1200 mu for YAG laser. The first experiment was to see the effect of nine combinations of simultaneous coaxial CO2 of 2, 4 and 8 watts and YAG lasers of 10, 20 and 40 watts, 1 sec on the brain. In the second experiment, also combining two lasers, the exposure time of YAG laser was elongated from 1 or 2 seconds into 2 or 4 seconds and the arrangement of powers was the same as that of the first experiment. The lesions were thus made in 18 different conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

[Topographic mapping of regional cerebral blood flow by xenon-enhanced CT--introducing a simplified method as a routine examination].

Measurement of regional cerebral blood flow (rCBF) has become a routine examinations in the field of clinical neurology and neurosurgery. Therefore, various methods for measuring rCBF have been developed. Among them, xenon-enhanced CT method has many advantages compared with others. An obtainable topographic flow map, high anatomical spatial resolution, and readily available instrument, namely CT scanner, are regarded as the advantages. On the one hand, anesthetic effects of xenon gas on the patients, taking a great expense for a single examination, and a significant dose of radiation delivered to the patients are thought to be the disadvantages. Due to the disadvantages, xenon-enhanced CT is regarded as an unpractical examination. In the paper, we introduce a method with a brief xenon inhalation, named a simplified method, with which the disadvantages can be avoided. Conventional xenon-enhanced CT requires 20 to 25 minute inhalation of xenon gas in order to achieve a saturation of xenon in the cerebral tissue for a calculation of the partition coefficients (L). In the simplified method, instead of using the calculated L, L was given as 1.0 in all the cerebral regions and xenon gas was terminated at 4 minute inhalation. Four minute inhalation of xenon gas did not make any significant anesthetic effects on the patients nor the changes of physiological parameters, such as, PaCO2 and blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Volume Determination↗
PubMed1984

Regional changes in cerebral blood flow and blood-brain barrier permeability during epileptiform seizures and in acute hypertension in rabbits.

Interrelationship between the breakdown of the blood-brain barrier (BBB) to Evans blue and elevations in the regional cerebral blood flow (rCBF) was studied in rabbits subjected to adrenaline- or metaraminol-induced systemic hypertension and also in bicuculline-induced seizures. The rCBF was assessed in small samples from various regions of the brain with the use of [3H]nicotine, and the permeability of the BBB was evaluated with an Evans blue tracer. In acute hypertension, Evans blue extravasations were observed in the occipital cortex and sometimes in the superior colliculus, i.e., the regions which also showed the highest elevations in rCBF. The breakdown of the BBB in acute hypertension was clearly related to the rate of mean arterial blood pressure rise, being much less pronounced in the metaraminol group, which showed a much slower blood pressure elevation rate. In bicuculline-induced seizures, there was no evident correlation between the amplitude of rCBF elevations and Evans blue extravasations. Preservation of BBB integrity was observed in areas showing high elevations in the rCBF.

Acute Disease↗
PubMed1984

Foreign body infection: role of fibronectin as a ligand for the adherence of Staphylococcus aureus.

Foreign bodies made of polymethylmethacrylate coverslips were implanted subcutaneously into guinea pigs, were explanted four weeks later, and were tested for in vitro adherence of Staphylococcus aureus strain Wood 46. In the presence of serum, the level of staphylococcal adherence to explanted coverslips was 20 times higher than that of adherence to unimplanted coverslips. Adherence to explanted coverslips was caused by fibronectin deposits on the foreign body surface and was inhibited in a dose-related fashion by specific antibodies to fibronectin.

Adhesiveness↗
PubMed1984

Arrest of DNA elongation by DNA polymerases at guanine adducts on 4-hydroxyaminoquinoline 1-oxide-modified DNA template.

In vitro modification of M13 phage single-stranded DNA with 4-hydroxyaminoquinoline 1-oxide (4HAQO) resulted in four kinds of adducts: three guanine adducts, QGI, QGII, and QGIII; and one adenine adduct, QA, at ratios of 16.4 47.3, 13.7, and 22.6, respectively. The carcinogen-modified DNA, initiated with a sequence-defined oligodeoxynucleotide primer, was replicated in vitro with Escherichia coli DNA polymerase I (Klenow fragment) and calf thymus DNA polymerases alpha and beta. The reaction products were analyzed on a DNA-sequencing gel. DNA elongation by DNA polymerase I was arrested at putative guanine adducts on the template in three ways: at one base prior to guanine; at positions opposite to guanine; and at one base beyond guanine. Similar patterns of elongation arrest were also obtained with the mammalian DNA polymerases alpha and beta. In contrast to guanine adducts, the adenine adduct, QA, might lack the capacity to arrest DNA chain elongation by DNA polymerases.

4-Hydroxyaminoquinoline-1-oxide↗