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Biomedical subjects

N Ikeda

Publications and source records attributed to N Ikeda.

At least 307 records · Page 17Linked to original sources
PubMed1987

Effects of KW-3049, a newly developed calcium antagonist, on rabbit sinus nodes and guinea pig ventricular muscles.

The effects of KW-3049, a newly developed dihydropyridine-type calcium antagonist, were studied on the electrophysiological properties of isolated rabbit sinus node tissues and guinea pig ventricular muscles. In spontaneously firing sinus node pacemaker cells, KW-3049 (greater than or equal to 10(-8) M) prolonged the cycle length, and decreased the maximum upstroke velocity (Vmax) and overshoot (OS) of action potential. KW-3049 (greater than or equal to 10(-6) M) produced a shortening of action potential duration (APD) of normally polarized ventricular muscles without affecting other parameters. Vmax, OS, and APD of slow action potentials, which had been induced by isoproterenol or by barium in K+-depolarized ventricular muscles, were reduced dose-dependently by KW-3049 (greater than 10(-9) M). The relative potency of KW-3049 for the Vmax inhibition of slow responses was 20 times higher than verapamil, but 0.32 times less than nifedipine. In voltage calmp experiments on ventricular muscles, KW-3049 (10(-6) M) caused a decrease of slow inward current by 52.7%, but did not affect the net outward current. These findings suggest that KW-3049 may have a potent and highly selective inhibitory action on cardiac slow channels.

Action Potentials↗
PubMed1987

Effects of ingested 4000ppm aluminum on the essential metals, especially zinc, in intact and ethanol treated mice.

The effects of ingested Al on the essential metals were investigated using mice. Animals were divided into 4 groups: 1) Control, 2) Al, 3) EtOH and 4) Al+EtOH groups. Powdered commercial food, containing 1.26% P, 1.36% Ca, 70ppm Zn, 15ppm Cu, 200ppm Fe and 3.1ppm Al, was used to prepare the diets. For Al-treated groups, Al(AlCl3) was added to powdered food at a concentration of 4000ppm. The co-existing effect of EtOH which is known to affect the essential metals, was also investigated as a possible modulater of Al toxicity at a concentration of 5% for 22 days, followed by 10% for 36 days in the drinking water. After 58 days feeding with food containing Al and / or EtOH containing water, the Al effects on serum and femur P and Ca were found to be slight except for a significant decrease of serum P concentration in the Al+EtOH group. In this group, femur weight was less and femur Al concentration was more compared with the Al group. The effects on Fe and Cu were little. We observed a significant decrease of serum Zn concentration with 4000ppm Al diet in both the Al-treated groups. The fact that serum ALPase activity, a Zn enzyme, increased in disregard of a significant decrease of serum Zn concentration suggested the enzyme release from injures tissues. It is noticeable that a significant decrease of serum Zn concentration was observed when dietary Zn was sufficient. It is reported that the dietary intake of Zn is under the recommended allowance for many people. Since Al compounds are widely used as drugs, food additives and a conditioned latent Zn deficiency is rather common in human diseases, the effects of Al on the Zn metabolism are to be investigated further.

Aluminum↗
PubMed1987

Distribution of uranium in human lungs.

Several human lung samples were dissected into lobes and uranium and silicon contents in each lobe were determined by the fission track method and the inductively coupled plasma-atomic emission spectrometry (ICP-AES), respectively. It was found that both uranium and silicon concentrations were high in the upper lobe compared with those in the lower one. Though the tendency may be mainly interpreted by the deposition way of airborne dust in the lung, the higher U/Si concentration ratio in the upper part than that in the lower part of lungs may suggest the partial removal of uranium deposited in the lower part of the tissue.

Air Pollution, Radioactive↗
PubMed1987

Distribution of uranium in human bones.

Uranium and calcium contents in human bones (skull, rib and femur) were determined by the fission track method and the inductively coupled plasma-atomic emission spectroscopic method (ICP-AES), respectively. The U/Ca concentration ratio in the bones was found to decrease in the order of rib greater than femur greater than skull, which is in accordance with the decreasing order of the mean annual replacement percentage of bone components. Several femur bones were cut into several longitudinal segments, and uranium and calcium contents in each segment were determined. Among these, the U/Ca ratio in the epiphysis was higher than those in the diaphysis.

Adult↗
PubMed1987

[Radiolysis and variation of anti-microbial activity of gamma-irradiated acrinol aqueous solution on radiosterilization].

The investigations about the radiolysis materials and their quantities, and, anti-microbial activities of gamma-irradiated (in the ranges of 0.516-2.064 kC/kg (2-8 MR] acrinol on liquid dosage form have been carried out to study the application of radiosterilization. About nine components were found as radiolysis materials. Most of them were also found in the UV-irradiated of Fenton's reagent-treated acrinol solution. Increase of anti-microbial activity was observed with gamma-irradiated acrinol solutions, but this phenomenon was not long-lasting. The micro-organism such as Pseudomonas aeruginosa or Staphylococcus aureus that infect at the lips of wound are highly sensitive to the gamma-irradiation. They are almost sterilized by the irradiation of 10 kGy (1.0 Mrad). At a low acrinol concentration, the decomposition rate of acrinol by the irradiation was relatively high. When 1.0% of acrinol solution was irradiated at a dose of 10 kGy (1.0 Mrad), the decomposition of the drug was less than 2% and the variation of anti-microbial activity was negligible.

Acridines↗
PubMed1987

Simultaneous determination of radioactive and stable isotopes of cobalt in environmental samples by the isotopic exchange method.

The isotopic exchange method is studied for the simultaneous determination of radioactive and stable isotopes of cobalt in environmental samples. Radioactive cobalt is isotopically exchanged with Co-CyDTA in HC1 solution of the sample. The solvent extraction method is used for the separation of Co2+ and Co-CyDTA species from each other. The amounts of radioactive and stable cobalt isotopes are calculated with activities of Co and Co-CyDTA at the exchange equilibrium. The methods for eliminating interfering ions are discussed. The results are in good concordance with those obtained by the conventional analytical methods.

Cobalt Isotopes↗
PubMed1987

Determination of DNA by sub- and super-equivalence method of isotope dilution analysis using enzyme reaction.

Sub- and super-equivalence method of isotope dilution analysis (SSE-IDA) using enzyme reaction was first applied for the determination of biological substance, DNA. Radioactive DNA (pUC18) to be analysed was prepared by incorporating 3H-thymidine in growing E. coli. A part of DNA was cut into the linear form (L-form) DNA under definite conditions using a restriction enzyme HindIII, following the separation of each by gel electrophoresis. Radioactivites of separated L-form DNA of two series were measured. The quantity of DNA was obtained by a graph method of SSE-IDA. As preliminary experiments, it was examined under what conditions the enzyme reaction proceeds as zeroth or first order reaction. We used the enzyme and substrate concentrations near zeroth order, where ordinary subst-IDA seems not to give a satisfactory results. As the results, 0.25 microgram of DNA was determined the error of about 10%.

DNA↗
PubMed1987

Plutonium and uranium in Japanese human tissues.

Plutonium and uranium in human tissues obtained from residents of the Tokyo area were determined by a-spectrometry and the fission track method, respectively. The distribution pattern of each element was estimated on the basis of mean concentration obtained. Plutonium is concentrated in some special organs, while uranium is distributed rather generally throughout the whole body. This difference of distribution tendency is considered to be due to the characteristics of stable chemical states of the elements in body fluid; Pu4+ for plutonium and UO2(2+) for uranium.

Asian People↗
PubMed1987

[Qualitative improvement of the surgical treatment of cancer using laser equipment--surgical technic after photodynamic therapy].

Nineteen patients with lung cancer were treated by combined preoperative photodynamic therapy (PDT) and surgery. Preoperative photodynamic therapy was performed for the purpose of either reducing the extent of resection or increasing operability. Clinically, nine patients had stage I disease, one had stage II, eight had stage III and one had stage IV. There were two cases of tracheal superficial invasion from primary lesions, three cases of intrabronchial polypoid tumor or superficial invasion of the carina by primary lesions, eleven cases of polypoid tumor or superficial invasion of the main bronchus, and three cases of double primary lesions. Argon dye laser was used in this study. Preoperative PDT was performed 48 to 72 hours after intravenous injection of hematoporphyrin derivative (HpD). Therapeutic conditions were 60 to 600 joules/cm2 for the superficial invasive areas and an additional 200 to 800 m W for 8 to 15 minutes for polypoid lesions. Surgical resection was performed 1 to 9 weeks after PDT. The initial purpose of PDT was achieved in 15 of the 19 patients treated. In five of six originally inoperable cases, conversion to an operable status was achieved. Thirteen patients were originally candidates for pneumonectomy, and it became possible to reduce the extent of resection to lobectomy in ten of them. This study suggests that PDT may have an important role in combination with surgery and other modalities in advanced lung cancers.

Adenocarcinoma↗
PubMed1987

A new method for typing haptoglobin in bloodstains using immobilized allo A lectin.

Allo A lectin from the beetle, which is beta-D-galactose specific, reacts to haptoglobin but not to hemoglobin. The use of allo A-Sepharose for typing haptoglobin in bloodstains helped eliminate hemoglobin from the bloodstain extract and presented highly resolved haptoglobin patterns by disc gel electrophoresis. This method is simple and rapid for typing haptoglobin in bloodstains and can be easily used in forensic science laboratories.

Animals↗
PubMed1986

[The course of respiration in death caused by obstructive asphyxia].

Experiments were carried out on 30 dogs to investigate the course of respiration during obstructive asphyxia. They were asphyxiated by occlusion of the exposed trachea. Intrathoracic pressure, blood pressure in the femoral artery, electrocardiogram and electroencephalogram readings were registered. In most cases, the respiration course during the dyspnea stage by occlusion of the trachea generally had an inspiratory character. In a few animals, when the trachea was occluded in the expiratory phase, there were a few positive expiratory respirations with moderate inspiratory movement and thereafter the respirations were inspiratory during the dyspnea stage. The terminal respirations, which occurred 1-2 min before the circulatory breakdown, were generally inspiratory, but in a few dogs they were expiratory.

Airway Obstruction↗