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Biomedical subjects

K Sano

Publications and source records attributed to K Sano.

At least 559 records · Page 31Linked to original sources
PubMed1987

A highly sensitive method for detection of 32P incorporation into acid-soluble compounds and its application to evaluate ATP-forming ability of Bacillus megaterium QM B1551 spores at the very early stage of germination.

A method for specific removal of [32P]orthophosphate (Pi) as phosphomolybdate-triethylamine complex was slightly modified by repeating the Pi precipitation procedures in the presence of unlabeled Pi, which resulted in a complete removal of 32Pi (greater than 99.98%). Using this modified method, we determined 32P incorporation into acid-soluble compounds in order to evaluate the ATP-forming ability of Bacillus megaterium spores at the very early stage of germination. Addition of fructose as a substrate started the 32P incorporation later than a few min after triggering germination. This delay of a few min was well coincident with the onset of 3-phosphoglycerate (3PGA) breakdown, indicating that fructose metabolism and the accompanying aerobic ATP formation were initiated only after fructose phosphorylation by the ATP derived from anaerobic breakdown of endogenous 3PGA. In contrast, addition of glucose started incorporation of 32P into acid-soluble compounds immediately after germination. In the latter case, NADH generated by glucose oxidation to gluconate (catalyzed by glucose dehydrogenase) might serve as an initial ATP source without depending on 3PGA breakdown and glucose metabolism via the Embden-Meyerhof pathway.

Adenosine Triphosphate↗
PubMed1987

Two single-base-pair substitutions causing desensitization to tryptophan feedback inhibition of anthranilate synthase and enhanced expression of tryptophan genes of Brevibacterium lactofermentum.

A 5-fluorotryptophan-resistant mutant, termed 1041, was isolated from Brevibacterium lactofermentum AJ12036. The anthranilate synthase of 1041 was insensitive to feedback inhibition by tryptophan, and the specific activities of the anthranilate synthase and anthranilate phosphoribosyltransferase of 1041 were 29- and 23-fold higher than those in parental strain AJ12036, respectively. A single-base change (adenine to cytosine) that resulted in a Ser-to-Arg substitution was found in the trpE structural gene of 1041. This substitution was identified as the cause of the desensitization to feedback inhibition by tryptophan of anthranilate synthase in 1041. Another substitution (guanine to adenine) was found at a position in which a mutation would destabilize the rho-independent terminator structure within the putative attenuator. The enhanced synthesis of tryptophan enzymes in 1041 could be caused by this substitution in the attenuator.

Amino Acid Sequence↗
PubMed1987

Antibody that inhibits human immunodeficiency virus reverse transcriptase and association with inability to isolate virus.

Most individuals infected with human immunodeficiency virus (HIV), the causative agent of acquired immune deficiency syndrome, produce an antibody against the viral reverse transcriptase (RT). Our studies show that 67% of HIV-seropositive individuals (33 of 49) produced an antibody that specifically inhibited viral RT enzyme activity. We were able to isolate HIV from only 18% of these individuals (6 of 33). On the other hand, virus was readily isolated from 63% of HIV-seropositive individuals (10 of 16) who did not demonstrate this antibody. Further examination of this RT-inhibiting antibody and its role during virus infection is needed, as it may prove to be of diagnostic, prognostic, or therapeutic value in this study and treatment of acquired immune deficiency syndrome.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Sensitive reverse transcriptase assay to detect and quantitate human immunodeficiency virus.

A sensitive biochemical assay of viral reverse transcriptase (RT) was developed that is useful for both the detection and quantitation of human immunodeficiency virus (HIV), the agent responsible for acquired immune deficiency syndrome in humans. This assay gave a 20- to 40-fold increase in enzyme activity over the current method used for RT detection of HIV. The test is based on a previous biochemical study showing the unusual stability of avian oncornavirus RNA-dependent DNA polymerases at 30 degrees C for at least 2 days. Our study shows that the HIV polymerase is stable at 30 to 37 degrees C for up to 3 days. By using this sensitive RT assay, as few as 250 HIV virions can be quantitated directly in tissue culture medium. This assay should prove useful in studies in which the detection of HIV or the quantitation of the number of virions is required.

Cell Line↗
PubMed1987

Effect of secretagogues on cytoplasmic free calcium in alveolar type II epithelial cells.

Pulmonary surfactant is synthesized and secreted by alveolar type II epithelial cells. Although intracellular calcium and other second messengers have been implicated in secretion by type II cells, this is the first report on measurement of cytoplasmic free calcium concentration ([Ca2+]i). Known secretagogues, 12-O-tetradecanoylphorbol-13-acetate (TPA) and terbutaline, were tested to see if they caused rapid increases in cytoplasmic calcium. Ionomycin, a calcium ionophore, was used to increase cytoplasmic free calcium concentration, to determine if a rapid increase in cytoplasmic free calcium would stimulate secretion, and to measure interactions with other secretagogues. Ionomycin increased both [Ca2+]i and pulmonary surfactant secretion from alveolar type II cells. A low concentration of ionomycin (100 nM) greatly enhanced secretion stimulated by terbutaline or by 8-bromo-cAMP but only had an additive effect on secretion stimulated by TPA. Terbutaline transiently increased [Ca2+]i by 24% over control basal condition, and the increase in [Ca2+]i produced by terbutaline occurred in the absence of extracellular calcium. TPA itself did not change [Ca2+]i. However, TPA completely inhibited the terbutaline-induced increase of [Ca2+]i but not the increase due to ionomycin. When alveolar type II cells were loaded with 2-(2-bis-[carboxymethyl]-amino-5-methyl-phenoxy)-methyl-6-methoxy-8-bis carboxymethylaminoquinoline (quin2) in calcium-free buffer, [Ca2+]i decreased from 143 +/- 10 to 31 +/- 8 nM. Lowering [Ca2+]i inhibited TPA- or terbutaline-induced secretion by 22 and 40%, respectively. Although the precise role of cytoplasmic free calcium on surfactant secretion cannot be established on the basis of current data, our results indicate that an increase in cytoplasmic free calcium produced by ionomycin stimulates secretion and that an increase in [Ca2+]i affects cAMP-induced secretion more than protein kinase C-mediated secretion in alveolar type II cells.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1987

Inhibitory action of bilirubin on superoxide production by polymorphonuclear leukocytes.

To assess the interaction of bilirubin with albumin and to determine the site of bilirubin toxicity in cells, a study was made of the O2- production of neonatal neutrophils (PMNs) by two different stimulators: (1) concanavalin A (Con A) plus cytochalasin D (Cyt D), which acts on the cell surface, and (2) phorbol myristate acetate, which acts intracellularly. PMNs that had been separated from cord blood were incubated for 60 min at 37 degrees C in the solution with different molar ratios of bilirubin/albumin (unbound bilirubin, ranging from 0.35 to 3.92 micrograms/dl). The unbound bilirubin was determined by peroxidase oxidation method. A PMN viability of more than 96% was maintained after the incubation in each of solutions. The O2- production rate of PMNs stimulated by Con A plus Cyt D was inhibited in the presence of unbound bilirubin levels as low as 1.12 micrograms/dl, and the rate decreased as the levels of unbound bilirubin rose. The O2- production rate stimulated by Con A plus Cyt D was more remarkably inhibited than that by phorbol myristate acetate, which directly activates intracellular protein kinase C. These findings suggest that bilirubin toxicity to PMN can be shown at levels of unbound bilirubin as low as those in hyperbilirubinemic sera, and the critical site at which bilirubin exerts its toxicity is mainly in membrane level rather than on intracellular functions.

Bilirubin↗
PubMed1987

[Effects of intravenous feeding on adjuvant chemotherapy--an experimental study on the distribution of 5-FU after injection of tegafur (1)].

Forty-eight male Donryu rats inoculated with Sato lung cancer were used to experimentally determine the effects of intravenous feeding on the concentrations of the chemotherapeutic agents FT-207 and 5-FU in the blood, as well as in the liver and tumorigenic tissue. Following FT-207 administration, the blood, tumor and liver tissue levels were lower than in the IVH group (oral administration). The liver 5-FU concentration, at 0.10 +/- 0.02 microgram/g, was significantly higher in the intravenous feeding group than in the p.o. group (0.05 +/- 0.01 micrograms/g). The 5-FU blood concentration rose quickly, reaching 0.051 +/- 0.013 micrograms/ml and 0.035 +/- 0.004 micrograms/ml at 9 and 12 hours, respectively, following treatment. This was significantly higher than in the p.o. group, which showed corresponding levels of 0.031 +/- 0.004 microgram/ml and 0.022 +/- 0.002 microgram/ml, respectively. The increase in the 5-FU level within the tumor was markedly high in the IVH group compared to the p.o. group, and it peaked at 9 hours following administration. The concentration in the IVH group was thus higher than in the p.o. group at any given time. At 24 hours after treatment, the IVH group level was 0.35 +/- 0.09 microgram/g, against 0.27 +/- 0.05 microgram/g in the p.o. group. The blood concentration of 5-FU following intravenous feeding maintained a high value for a long time, and the 5-FU tumor concentration also remained at a high level. The intravenous route was therefore considered to be advantageous for antitumor chemotherapy.

Animals↗
PubMed1987

[Serum concentration of 5-FU and tegafur (FT-207) after administration of tegafur (FT-207) suppository with the colostomy].

Tegafur (FT-207) suppositories were administered at a rate of 750 mg via the artificial anus (ST Group) following surgery of rectal cancer. Comparative studies were conducted of changes in blood concentrations of 5-FU and tegafur at the time of initial administration and following one week of continuous use for the low-anterior resection cases (LA Group) and the rectal administration cases (RE Group). FT-207 concentration at initial administration was low in the ST group compared to those for both LA and RE groups which received anal administration of the drug, but only little changes were noted. Blood concentration one hour after administration was 11.1 micrograms/ml, elevated to 14.3 micrograms/ml at two hours, and remained at 10 micrograms/ml and above for six hours following administration. The ST group 5-FU concentrations at two, four and six hours after administration were significantly lower than those in the RE group but the changes were little. Blood concentrations were 0.015 microgram/ml at one hour after administration, 0.017 micrograms/ml at two hours and maintained virtually the same level thereafter. An effective concentration of 0.012 microgram/ml was maintained even at ten hours following administration. After one week of administration of the suppositories, the ST group showed the lowest concentration among three groups, but it was approximately double compared to the initial concentration; FT-207 showed nearly the same concentration in the LA group and 5-FU blood concentration was 0.025 microgram/ml at one hour after administration, reached to a maximum of 0.030 microgram/ml at two hours and maintained 0.020 microgram/ml and higher at ten hours. 5-FU concentration in the LA and RE groups after one week of continuous administration showed a dual-peaked pattern. No patient with an abnormal artificial anus was involved in this study. The artificial anus is thought to be an adequate and effective administration route of FT-207 suppositories.

Adult↗
PubMed1987

[Effects of intravenous alimentation on adjuvant chemotherapy--an experimental study on the distribution of 5-FU after injection of tegafur (2)].

The stomach, small and large intestines, heart, lungs, bone and kidneys were removed from 48 Sato lung cancer-bearing rats used in the previous experiments and given 90 mg/kg of tegafur (FT-207) by single intravenous administration and tissue 5-FU and FT-207 concentrations were measured. FT-207 concentration in the alimentary canal was somewhat lower than the blood concentration, but both were lowered in parallel. 5-FU concentration in the stomach and large intestines showed virtually identical changes in both IVH and PO groups, but IVH group tended to have higher concentration. IVH group showed higher values than PO group anytime, particularly in the large intestines. A reduction of the side effects on the digestive system via intravenous alimentation was thought due to the elimination of mechanical stimulation via a cessation of oral feeding. 5-FU concentration in the bone was highest in PO group at six hours after administration and blood concentration changes were parallel, but there was virtually no change in IVH group. Maximum values were found one hour after administration and slowly declined thereafter; at 24 hrs the values were 0.059 +/- 0.013 microgram/g, relatively high compared to the PO group at 0.041 +/- 0.022 microgram/g. In the present study under intravenous alimentation, the concentration changes were slight in spite of 5-FU maximum concentration being lower than that by oral feeding and the long-term high concentration which was maintained; this is thought to be a disadvantageous action with regard to the bone marrow. FT-207 concentration in the kidney, heart and lungs was the same as that for the blood, with a gradual reduction in IVH group. 5-FU concentration was the same for the kidneys and IVH group quickly reached to the high levels compared to PO group with only slight changes thereafter. Effects of continuous water load might be involved but not clear.

Animals↗
PubMed1987

[Right ventricular function in patients with chronic obstructive pulmonary disease measured by krypton-81m].

Right ventricular function was assessed at rest and during exercise in patients with chronic obstructive pulmonary disease (COPD). Right ventricular ejection fraction (RVEF) was measured by first-pass radionuclide angiography using ultrashort-lived radionuclide krypton-81m. The half-life of this nuclide is only 13 sec, and it is completely expired from the lungs. These properties allow measurement of RVEF without correcting for background activity. In 30 patients with cardiac or pulmonary disease, RVEF was first measured by krypton-81 m scintigraphy (Kr-RVEF), then by technetium-99m (Tc-RVEF), without changing the patients' positions. In eight of the 30 cases, right ventricular cineangiography (RVG) was performed within 72 hrs after the radionuclide study, and RVEF was measured according to the Chapman's rule (RVG-RVEF). Kr-RVEF correlated significantly with Tc-RVEF (r = 0.87), and also with RVG-RVEF (r = 0.80). In 10 patients with stable COPD, who had severe hypoxemia (PaO2 less than or equal to 60 mmHg) and pulmonary hypertension [mean pulmonary arterial pressure (mean PAP) greater than or equal to 20 mmHg], and in seven normal control subjects, radionuclide angiographic and hemodynamic monitoring were performed at rest and during supine ergometer exercise. Kr-RVEF at rest was 47.6 +/- 5.4% (mean +/- SD) in patients with COPD and was 54.1 +/- 4.8% in normal subjects. Kr-RVEF during exercise was 51.8 +/- 7.3% in the patients, and 62.3 +/- 3.2% in the normal subjects. Hemodynamically, mean PAP and pulmonary vascular resistance (PVR) increased significantly during exercise, but the RV end-diastolic volume index (RVEDVI) did not change. There was inverse correlation between Kr-RVEF and mean PAP (r = -0.51) or PVR (r = -0.47) as an index of RV afterload. However, there was no correlation between Kr-RVEF and RVEDVI as an expression of RV preload. These findings suggest that a poor response by RVEF during exercise in patients with COPD is associated with elevation of afterload. Thus, right ventricular imaging techniques using the ultrashort-lived nuclide krypton-81 m allow noninvasive, serial and accurate assessments of right ventricular function in patients with COPD.

Aged↗
PubMed1987

[Surgical indication for extracranial-intracranial arterial bypass determined by cerebral blood flow study and neurological function--a retrospective study].

In order to establish more strict and objective indication for EC-IC bypass, a retrospective study on the surgical effect on cerebral blood flow (CBF) and neurological function was carried out in 37 cases. STA-MCA bypass was carried out on 20 cases with IC occlusion and 17 cases with MCA occlusion. Twenty-two cases with completed stroke, 9 cases with TIA and 6 cases with RIND. All patients were able to ambulate before surgery, and none of them were hemiplegic. CBF study by 133Xe inhalation method was carried out before and 2 to 4 weeks after surgery. Bypass was patent in all cases. Thirty percent of all cases showed more than 16% increase in CBF (++ group) on the side of bypass surgery and another 30% demonstrated 6 to 15% increase (+). On the other hand 30% of cases appeared to be unchanged (+/-), and 10% showed more than 6% decrease (-). The less the pre-operative CBF value was, the more the post-operative CBF was expected to be increased. Patients with pre-operative CBF less than 60% of normal value (ISI = 63 +/- 4) showed remarkable increase (++), and those with 60 to 70% showed moderate increase (+). Contrarily, cases with more than 70% of normal value showed either no change or decrease. Neurological change was evaluated as to disappearance of TIA attack and improvement of hemiparesis or mental dysfunction. Seventy-seven percent of patients in groups with (++) and (+) effect on CBF showed improvement in neurological function, whereas only 27% of patients in groups with (+/-) and (-) effect demonstrated improvement, which was statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain↗
PubMed1987

Temporal raphe of the retinal nerve fiber layer revealed by medullated fibers.

Three cases of medullated nerve fibers of the retina were seen. They had medullated nerve fibers in both the upper and lower quadrants of the temporal retina, whereby the temporal raphe of the retinal nerve fiber layer could be visualized. Some nerve fibers from the upper and lower quadrants crossed each other on the horizontal meridian. The structure of the temporal raphe reported by Vrabec through anatomical studies was confirmed by ophthalmoscopy.

Adult↗
PubMed1987

[New fixative for pathological specimens in cold areas].

In cold areas where the lowest temperature of the day can fall to minus 20 degree Celsius in winter, surgical specimens which are sent from the local hospitals to the pathology department often become frozen during delivery. Although the antigenicity of tissues may remain intact, pathological diagnosis is difficult due to the destruction of the tissue by freezing. To overcome this difficulty and the development of artifact, we have attempted to make a fixative based on a 10% formalin solution to provide good fixation effect. Various mixtures of 10% formalin with sucrose, dimethyl sulfoxide (DMSO), glycerin, ethylene glycol and polyethylene glycol were prepared in different concentrations. Tissues of liver, kidney and stomach taken from autopsy or surgical biopsy were fixed with each solution at room temperature for 24 hours and then exposed to -20 degrees C for 2 days. After they were returned to room temperature, they were embedded in paraffin and stained with H&E and immunohistochemically examined by the PAP method. It could be shown that 10% formalin containing 20% ethylene glycol was the most suitable "fixative" to use. The specimens did not freeze and examination of the tissues showed that the morphology and antigenicity remained intact. In addition, this solution could be prepared easily and economically.

Cold Temperature↗