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Biomedical subjects

K Nitta

Publications and source records attributed to K Nitta.

At least 271 records · Page 15Linked to original sources
PubMed1987

Amino acid sequence of sialic acid binding lectin from frog (Rana catesbeiana) eggs.

The complete amino acid sequence of sialic acid binding lectin from frog (Rana catesbeiana) egg is presented. The 111-residue sequence was determined by the analysis of peptides generated by digestion of the S-carboxymethylated protein with Achromobacter protease I, chymotrypsin, or cyanogen bromide. The sequence is unique and not homologous to any known protein sequence. The protein may represent a new type of lectin.

Amino Acid Sequence↗
PubMed1987

67Ga accumulation in inflammatory lesion and its mechanism: comparison with malignant tumor.

The accumulation of 67Ga in inflammatory lesions increased with time after injection of turpentine oil and reached a plateau 5 days later. At that time the uptake in the lesions was larger than any other tissue, after ten days the lesion uptake decreased. In experiments using rats which had been kept for 5 days after subcutaneous injection of turpentine oil, the accumulation of 67Ga in inflammatory lesions increased with time until six days after administration of 67Ga-citrate. It is clear from this study that 67Ga is avidly accumulated in areas where the subcutaneous tissue is infiltrated with neutrophils and macrophages, that it is not accumulated at the sites in which neutrophils are crowded, that nuclear material, mitochondria, lysosomes and microsomes do not play a major role in 67Ga accumulation in the lesion and that the main binding acid mucopolysaccharide in the lesion is a acid mucopolysaccharide which is none of the following: keratan sulfate, heparan sulfate, heparin, or chondroitin sulfate A, B or C. It is presumed that the main 67Ga binding acid mucopolysaccharide is keratan polysulfate (or other oversulfated acid mucopolysaccharides).

Animals↗
PubMed1987

Potentiation of the chemotherapeutic action of 5'-deoxy-5-fluorouridine in combination with guanosine and related compounds.

The effect of inosine, guanosine, and guanosine 5'-monophosphate (GMP) on the antitumor activity of 5'-deoxy-5-fluorouridine (5'-DFUR) was investigated using P388 leukemia and P815 mastocytoma. The antitumor activity of 5'-DFUR was markedly enhanced by coadministration of inosine or guanosine. The increase in lifespan (ILS) of mice treated with 5'-DFUR was augmented by the combination with guanosine or inosine in a dose-dependent fashion, and the maximum ILS was about 160% with the combination, while that in the case of 5'-DFUR alone was only 48% in the P388 leukemia system. The therapeutic ratio (dose at ILSmax/dose at ILS30) of the combination with guanosine or inosine was 333 and 136, respectively, whereas that of 5'-DFUR alone was 3.6. GMP also markedly potentiated the antitumor activity of 5'-DFUR in both P388 leukemia and P815 mastocytoma systems, just as it potentiated the activity of 5-fluorouracil in the latter system. The uric acid level in the serum was elevated after IP injection of guanosine or inosine but the value was much lower in the case of guanosine than in inosine.

Animals↗
PubMed1987

Food production and gas exchange system using blue-green alga (Spirulina) for CELSS.

In order to reduce the cultivation area required for the growth of higher plants in space adoption of algae, which have a higher photosynthetic ability, seems very suitable for obtaining oxygen and food as a useful source of high quality protein. The preliminary cultivation experiment for determining optimum cultivation conditions and for obtaining the critical design parameters of the cultivator itself has been conducted. Spirulina was cultivated in the 6-liter medium containing sodium hydrogen carbonate solution and a cultivation temperature controlled using a thermostat. Generated oxygen gas was separated using a polypropyrene porous hollow fiber membrane module. Through this experiment, oxygen gas (at a concentration of more than 46%) at a rate of 100-150 ml per minute could be obtained.

Air Conditioning↗
PubMed1987

Vapor compression distiller and membrane technology for water revitalization.

Water revitalization for a space station can consist of membrane filtration processes and a distillation process. Water recycling equipment using membrane filtration processes was manufactured for ground testing. It was assembled using commercially available components. Two systems for the distillation are studied; one is an absorption type thermopervaporation cell and the other is a vapor compression distiller. Absorption type thermopervaporation able to easily produce condensed water under zero gravity was investigated experimentally and through simulated calculation. The vapor compression distiller was studied experimentally and it offers significant energy savings for evaporation of water.

Absorption↗
PubMed1987

Fundamental study on gas monitoring in CELSS.

A mass spectrometer and computer system was developed for conducting a fundamental study on gas monitoring in CELSS. Respiration and metabolism of the hamster and photosynthesis of the Spirulina were measured in a combination system consisting of a hamster chamber and a Spirulina cultivator. They are connected through a membrane gas exchanger. Some technical problems were examined. In the mass spectrometric gas monitoring, a simultaneous multi-sample measurement was developed by employing a rotating exchange valve. Long term precise measurement was obtained by employing an automatic calibration system. The membrane gas sampling probe proved to be useful for long term measurement. The cultivation rate of the Spirulina was effectively changed by controlling CO2 and light supply. The experimental results are helpful for improving the hamster-spirulina system.

Air Conditioning↗
PubMed1987

The applicability of catalytic wet-oxidation to CELSS.

The wet-oxidation catalysis of Au, Pd, Pt, Rh or Ru on a ceramic honeycomb carrier was traced in detail by 16 to 20 repetitive batch tests each. As a result, Pt or Pd on a honeycomb carrier was shown to catalyze complete nitrogen gasification as N2. Though the catalysts which realize both complete nitrogen gasification and complete oxidation could not be found, the Ru+Rh catalyst was found to be most promising. Ru honeycomb catalyzed both nitrification and nitrogen gasification.

Bioreactors↗
PubMed1987

An overview of Japanese CELSS research activities.

Many research activities regarding Controlled Ecological Life Support System (CELSS) have been conducted and continued all over the world since the 1960's and the concept of CELSS is now changing from Science Fiction to Scientific Reality. Development of CELSS technology is inevitable for future long duration stays of human beings in space, for lunar base construction and for manned mars flight programs. CELSS functions can be divided into two categories, Environment Control and Material Recycling. Temperature, humidity, total atmospheric pressure and partial pressure of oxygen and carbon dioxide, necessary for all living things, are to be controlled by the environment control function. This function can be performed by technologies already developed and used as the Environment Control Life Support System (ECLSS) of Space Shuttle and Space Station. As for material recycling, matured technologies have not yet been established for fully satisfying the specific metabolic requirements of each living thing including human beings. Therefore, research activities for establishing CELSS technology should be focused on material recycling technologies using biological systems such as plants and animals and physico-chemical systems, for example, a gas recycling system, a water purifying and recycling system and a waste management system. Based on these considerations, Japanese research activities have been conducted and will be continued under the tentative guideline of CELSS research activities as shown in documents /1/, /2/. The status of the over all activities are discussed in this paper.

Air Conditioning↗
PubMed1987

Transplacental stimulation of functional and morphologic fetal rabbit lung maturation: effect of thyrotropin-releasing hormone.

We investigated the effect of maternally administered thyrotropin-releasing hormone on functional and morphologic fetal lung maturation. Thyrotropin-releasing hormone (40 micrograms/kg/day) or the vehicle was injected intravenously into the New Zealand White rabbit does on days 25, 26, and 27 of gestation. On day 27 of pregnancy, the does were killed and the fetuses were delivered. The functional pulmonary maturity was assessed by pressure-volume hysteresis while morphologic maturity was assessed by histologic techniques. Enhanced functional and morphologic fetal lung maturation was noted in animals treated with thyrotropin-releasing hormone when compared with controls. An important role of thyrotropin-releasing hormone in fetal lung maturation is proposed.

Animals↗
PubMed1987

A case of congenital colonic atresia associated with atresia ani.

The association of atresia ani with congenital colonic atresia is extremely rare, with only one such case having been reported up to date. We have recently treated a female infant with atresia ani (covered anus complete) accompanied by atresia of the sigmoid colon, who was managed by three stage surgery.

Anal Canal↗
PubMed1987

Granular juxtaglomerular cell hyperplasia caused by cyclosporine.

Histologic study of kidneys from rabbits given cyclosporine (CsA) revealed a marked hyperplasia of granular cells in the juxtaglomerular (JG) apparatus, but without a significant increase in the total cell number of JG cells. The increase in granular JG cells as compared with the control group was 204% and 406% for 30 mg/kg alternate days and 30 mg/kg daily groups, respectively. The increases for the lower-dosage groups were much smaller, although the increases were statistically significant for all but the 10 mg/kg alternate-days group. Other studies suggest that sympathomimetic activity of CsA may be the mechanism involved in granular JG cell hyperplasia.

Animals↗
PubMed1987

Antitumor activity of a new camptothecin derivative, SN-22, against various murine tumors.

The antitumor activity of a new camptothecin derivative, SN-22, was evaluated by using various murine tumors. SN-22 showed strong activity against the ascites tumors Ehrlich carcinoma, MM46, CCM, L1210, L5178Y, P388, Meth A, and B16 melanoma. In particular, the maximum increase in life span values for Ehrlich, MM46 and CCM were as high as 253-606% and many mice were cured of these tumors. The effect of SN-22 against solid tumors was also determined. The inhibition ratios were higher than 70% for MM46 and L5178Y. The LD50 of SN-22 in ICR mice was about 1.5 times that of the parent camptothecin.

Animals↗
PubMed1987

Experimental model for predicting metastatic ability of tumors using chick embryo.

At present, there is no established diagnostic method by which the metastatic ability of an individual human cancer can be accurately predicted. We used chicken chorioallantoic membrane (CAM) to predict the metastatic ability of three B16 murine melanoma variant lines and also of human giant-cell carcinoma of the lung. Tumor cells were deposited on the CAM of eggs 10 days after fertilization. On day 7 after the tumor inoculation, the embryos were killed, and the lungs removed, minced and implanted on the CAM of other 10-day-old embryos. On day 7 after this inoculation, the tumors on the CAM were inspected under a surgical microscope, and were also checked histologically. The results accurately reflected the differing metastatic abilities of the B16 melanoma variant lines. Metastases were observed in the lungs of the embryo bearing human giant-cell carcinoma of the lung on the CAM. Using CAM seems to be a suitable way of predicting the malignancy of tumors with metastatic ability.

Animals↗
PubMed1987

Renal effects of synthetic rat-atrial natriuretic peptide in nephron-reduced rats with nephrotoxic nephritis.

Following nephron reduction by means of five--sixths nephrectomy (Nx), nephritis was induced in rats by injection of nephrotoxic serum (NTS). A continuous intravenous infusion of synthetic rat--atrial natriuretic peptide (r-ANP) at 2.5 micrograms/min for produced remarkable diuresis and natriuresis in these rats. Furthermore, inulin clearance, para-amino-hippuric acid clearance and filtration fraction increased in spite of the reduction of mean arterial pressure during the infusion of r-ANP. It was therefore evident that diuresis and natriuresis were mediated by a direct action of r-ANP in the kidney. We observed that r-ANP was a diuretic, natriuretic and hypotensive agent but at a higher dosage in Nx rats with NTN.

Animals↗
PubMed1987

Response to antitumor agents of murine transplantable tumors implanted onto chorioallantoic membrane of chick embryo.

The chorioallantoic membrane of chick embryo was used to examine the chemosensitivity of the murine tumors, B16-F1 melanoma, B16-F10 melanoma, Meth-A fibrosarcoma, and Ehrlich carcinoma. The tumors were grown on the membrane, and the effects of 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride, cyclophosphamide, dacarbazine, 5-fluorouracil, methotrexate, adriamycin, mitomycin C, vincristine, and cisplatin on the growth of the tumors were tested by iv injection into a vein of the chorioallantoic membrane or injection into the yolk sac. The use of chick embryo limits the time for drug exposure to 3 or 4 days, but Ehrlich carcinoma and Meth-A fibrosarcoma needed longer for the test; the use of irradiation from a cobalt source overcame the problem by increasing the growth rate of the grafts of these two tumors. There appeared to be a good correlation between the effects of the drugs on B16 melanomas grown in the eggs and in the original animals. Many compounds, including pro-drugs such as cyclophosphamide and dacarbazine, could be assayed in this way.

Allantois↗