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Biomedical subjects

J Yano

Publications and source records attributed to J Yano.

At least 109 records · Page 6Linked to original sources
PubMed1981

Phagocytic activity and hyperpolarizing responses in L-strain mouse fibroblasts.

1. Fibroblastic L cells not only respond with a slow hyperpolarizing potential change to a mechanical or electrical stimulus but also show spontaneous, repetitive hyperpolarizations (i.e. membrane potential oscillation). 2. Almost all the cells can actively take up latex beads whose surfaces were treated by U.V. irradiation. 3. Non-phagocytic L cells hardly showed hyperpolarizing responses, while hyperpolarizing responses were obtained in all the phagocytic L cells. The exposure of the cell surface to beads, however, did not trigger the generation of hyperpolarizing responses. 4. Metabolic inhibitors, low temperature and cytochalasin B inhibited both the uptake of beads and the hyperpolarizing responses. 5. Increasing the external concentration of Ca2+ induced a remarkable stimulation of the phagocytosis of beads. Mg2+ and Ba2+, which inhibited hyperpolarizing responses due to competition for Ca2+ sites on the outer surface of the membrane, significantly suppressed the uptake of beads. 6. Verapamil, a Ca2+ channel blocker, inhibited not only hyperpolarizing membrane responses but also ingestion of beads. 7. It is concluded that the Ca2+ inflow on the hyperpolarizing membrane responses is closely associated with the phagocytic activity in L cells, probably through activation of the microfilament assembly.

Animals↗
PubMed1981

Bilateral primary malignant neoplasms of the maxillary sinus: report of a case and statistical analysis of the reports in Japan.

Although double primary malignant neoplasms of bilateral maxillary sinuses wee regraded as extremely rare, there have been 50 patients described in Japan since 1937. Among them only eight cases showed the histologic distinction between both sides. A 64-year-old man with double primary carcinomas had a mucoepidermoid carcinoma of the left maxillary sinus and a papillary adenocarcinoma of the right one with an interval of three years. He was treated with a combination of surgery, radiotherapy and regional chemotherapy. The histologic combination of these tumors could not be found so far. The advantage of this combination treatment for the carcinoma of the maxillary sinus is stressed.

Adenocarcinoma, Papillary↗
PubMed1981

[Subacute toxicity and recovery tests of mequitazine in beagle dogs (author's transl)].

Subacute toxicity and recovery tests of Mequitazine, a new phenothiazine ;type anti-histamine agent, were carried out using each 20 male and female dogs. The drugs was administered orally in doses of 0, 1, 5 and 25 mg/kg day for 14 weeks. Recovery test was carried out for following 4 weeks. As a result, transient decrease of the body weights and somnolences were observed in both male and female dogs given 25 mg/kg. In a female dog given 25 mg/kg, extrapyramidal reaction accompanied with tremors and muscle stiffenings was observed. But no dead animals were observed throughout experimental period. Vomitings, mydriasis and loss of appetite were observed with the dose-responsiveness, but these symptoms were reduced after 1-2 weeks administration. No abnormal changes were observed in hematological, serum biochemical, and other examinations. In histopathological examinations, slights changes were observed in liver, kidneys, mesenteric lymph nodes, palpebra and conjunctival membrane. But these changes were reversible in recovery period. From these results, it was suggested that the maximum non-effective and maximum safety doses were 1 mg/kg/day and 5 mg/kg/day, respectively.

Animals↗
PubMed1981

Oscillation of membrane potential in syncytiotrophoblast of human term placenta in culture.

The membrane potentials and resistances of the cultured syncytiotrophoblast of human chorionic villi obtained from normal term placentas were measured using a standard electrophysiological technique. The mean value of membrane potentials and resistances for 156 cells in the control tris-buffered saline at 37 degrees C were -40.0 +/- 1.2 mV and 8.6 +/- 0.7 M omega (mean +/- S.E.), respectively. The membrane potential was markedly affected by the change of external concentration of Ca++ or K+. In 32 cells among 156 cells examined, spontaneous oscillations of membrane potentials were observed. They oscillated between around -38 mV and -57 mV with the average frequency of 2.4 +/- 0.2 times per minute, accompanied by decrease in membrane resistance on each hyperpolarization. Although oscillations of membrane potentials have been observed in other cultured cells, this is the first report on the oscillation of membrane potential in the human trophoblast.

Cells, Cultured↗
PubMed1980

Proton nuclear magnetic resonance studies on dideoxyribonucleoside methylphosphonates.

A series of dideoxyribonucleoside methylphosphonates, d-ApA, d-ApT, d-TpA, and TpT, were synthesized chemically and the diastereoisomers of each dimer were separated [Miller, P. S., Yano, J., Yano, E., Carroll, C., Jayaraman, K., & Ts'o, P. O. P. (1979) Biochemistry 18, 5134]. The 1H NMR spectra of these compounds are similar to those of their parent diester compounds. Specifically, the assignments of the 1H resonances of the two diastereoisomers of d-ApA (designated as 1 and 2) were reaffirmed by comparing with the unmodified, parent d-ApA. The absolute configuration of the phosphonate methyl group of the two isomers (d-ApA)1 and (d-ApA)2 was determined by the NOE technique. The 1H NMR spectra of the diastereoisomers of d-ApA, as well as the corresponding monomer components dAp and CH3pdA, and TpT were analyzed by spectrum simulation techniques. Thus, all the coupling constants and chemical shifts of the proton resonances of the deoxyribofuranose ring and the phosphonate methyl group could be precisely determined. These data provide the information for an analysis of the sugar puckering and backbone conformations of these novel nonionic nucleic acid analogues. It was found that the conformations of the sugar-phosphate backbones of each isomer are similar to each other and are similar to the conformations of the parent dinucleoside monophosphates. The average adenine stacking conformations of (d-ApA)1 and (d-ApA)2 were described in numerical coordinates derived from a computer analysis which included both ring-current magnetic anisotropy and atomic diamagnetic anisotropy effects. The two computer-derived conformational models are similar to those derived from the graphic approximation based only on the ring-current effects. For each pair of dimer analogues, the base stacking mode of isomer 1 is similar to that of its parent diester while the extent of base overlap in isomer 2 is less than that in isomer 1. The results of the conformational analysis based on NMR data are consistent with the results obtained from ultraviolet and circular dichroism measurements on these dimers.

Deoxyribonucleotides↗
PubMed1980

A simple method of the preparation of 2'-O-methyladenosine. Methylation of adenosine with methyl iodide in anhydrous alkaline medium.

A simple and effective method of the methylation on the 2'-O position of adenosine is described. Adenosine is treated with CH3I in an anhydrous alkaline medium at 0 degrees C for 4 h. The major products of this reaction are monomethylated adenosine at either the 2'-O or 3'-O position (total of 64%) and the side products are dimethylated adenosine ((2', 3'-O-dimethyladenosine, 21%, and N6-2'-O-dimethyladenosine, 11%). The ratio of 2'-O- and 3'-O-methyladenosine has been found to be 8 to 1. Therefore, this reaction preferentially favors the synthesis of 2'-O-methyladenosine. The monomethylated adenosine is isolated from reaction mixture by a silica gel column chromatography. Then the pure 2'-O-methyladenosine can be separated by crystallization in ethanol from the mixture of 2'=O and 3'-O-methylated isomers. The overall yield of 2'-O-methyladenosine is 42%.

Adenosine↗
PubMed1980

Application of cephalosporins to obstetrics and gynecology: transfer of cefazolin and cephalothin to uterine tissue.

Antibiotics should be administered so as to maintain effective therapeutic levels in target organs. In routine clinical treatment, however, doses of antibiotics are determined on the basis of their achievable concentrations in blood. To determine the optimum doses of antibiotics against obstetric and gynecologic infections, the authors gave a single intravenous dose of 2 gm of cefazolin or cephalothin to 51 patients before hysterectomy and measured the levels of the antibiotics in uterine tissues and compared them with corresponding serum levels. The maximum tissue levels of cefazolin were generally about 6 to 7 times higher than those of cephalothin: In tthe perimetrium, levels were 154 microgram/gm for cefazolin and 24.1 microgram/gm for cephalothin; in the myometrium, 109.5 microgram/gm for cefazolin, and 15.5 microgram/gm for cephalothin; and in the endometrium, 98.9 microgram/gm for cefazolin and 10.4 microgram/gm for cephalothin. In the tissues, however, cephalothin reached peak levels more rapidly than cefazolin. Comparisons of the tissue levels and MIC of cefazolin and cephalothin revealed that cefazolin was maintained at over 12.5 microgram/gm for at least 150 minutes in the perimetrium, myometrium, and endometrium, whereas cephalothin was maintained at these levels for 40 to 50 minutes only in the perimetrium and myometrium. The ratio of tissue levels to serum levels was 40-70 to 100 for cefazolin and about 30 or less to 100 for cephalothin.

Adult↗
PubMed1979

Nonionic nucleic acid analogues. Synthesis and characterization of dideoxyribonucleoside methylphosphonates.

A series of dideoxyribonucleoside methylphosphonate analogues, dNpN and dNpNp, which contain a nonionic 3'--5' methylphosphonyl internucleoside linkage were prepared. The two diastereoisomers, designated isomers 1 and 2, of each dimer differ in configuration of the methylphosphonate group and were separated by column chromatography. The diastereoisomers of each dimer have different conformations in solution as shown by ultraviolet hypochromicity data and their circular dichroism spectra. For example, dApA isomer 1 is more highly stacked than isomer 2, although both isomers are less stacked than the dinucleoside monophosphate, dApA. The circular dichroism spectrum of isomer 1 is very similar to that of dApA, while the CD spectrum of isomer 2 shows a loss of molecular ellipticity, [theta], at 270 nm and a greatly diminished [theta] at 250 nm. These results suggest that the stacked bases of dApA isomer 1 tend to orient in an oblique manner, while those in isomer 2 tend to orient in a parallel manner. This interpretation is verified by the 1H NMR study of these dimers (L. S. Kan, D. M. Cheng, P. S. Miller, J. Yano, and P. O. P. Ts'o, unpublished experiments). Both diastereoisomers of dAaA form 2U:1A and 2T:1A complexes with poly(U) and poly(dT), respectively. The higher Tm (Tm of poly(U)--isomer 1, 15.4 degrees C; Tm of poly(U)--isomer 2, 19.8 degrees C; Tm of poly(dT)--isomer 1, 18.7 degrees C; Tm of poly(dT)--isomer 2, 18.4 degrees C) values of these complexes vs. those of the corresponding dApA--polynucleotide complexes (Tm of poly(U)--dApA, 7.0 degrees C; Tm of poly(dT)--DApA, 9.2 degrees C) result from decreased charge repulsion between the nonionic dimer backbone and the negatively charged polymer backbone. The difference in conformations between dApA isomer 1 and dApA isomer 2 is reflected in the Tm of the isomer 1-poly(U) complex which is 4.4 degrees C lower than that of the isomer 2-poly(U) complex. Since these nonionic oligonucleotide analogues are taken up by cells in culture, they show promise as molecular probes for the function and structure of nucleic acids inside living cells.

Circular Dichroism↗