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Biomedical subjects

K Ando

Publications and source records attributed to K Ando.

At least 505 records · Page 28Linked to original sources
PubMed1990

[Resin adhesion on the primary ground enamel. (2) Influence of the etched enamel].

The purpose of this study was to investigate the influence of the etching times on the adhesion of the resin on the primary ground enamel. Fifty extracted and frozen bovine mandibular primary incisors were used. The etchant used in this study was 37% phospholic acid gel and the etching times were 0, 10, 20, 30 and 60 seconds. All of the specimens were washed with an air water spray after etching. The bonding agent and composite resin used in this study were Dual Cured Scotch Bond and Silux (3M Co.). Shear bond strengths on the ground enamel were measured. After the shear bond strength test, all the test surfaces of the enamel and resin specimens were observed using the SEM. The results of this study were compared with the previous results using Photo Bond and Photo Clearifil A (Kurarey Co.). 1) The etching time which showed the highest bond strength was 20 seconds (76.77 +/- 12.99 Mpa). 2) When the enamel was etched with all of the etching times, the bond strength were significantly higher than that of the enamel without etching (p less than 0.01). 3) In the etched groups, there was no significant difference among the bond strengths with all of the etching times categories. 4) In the etched groups, the longer the etching times, the lower the standard deviations were. 5) On the enamel specimens after the shear bond strength test, the frequency of the resin tags fractured inside of the enamel prisms was higher in the group which showed a lower bond strength. 6) For the same etching times, significant difference between the bond strengths of Silux and those of Photo Clearfil A was obtained only with the 20 seconds of etching time (p less than 0.01) and the bond strength of Silux was higher.

Acid Etching, Dental↗
PubMed1990

[Clinical efficacy of ifosfamide for liver metastasis of breast cancer].

Chemotherapy for liver metastasis of breast cancer has rarely been found effective. We devised a new regimen of chemotherapy for recurrent breast cancer mainly using ifosfamide. It was found clinically applicable and particularly effective for liver metastasis. The tumor decreased in size and the levels of various tumor-markers markedly decreased following drug administration. This treatment has made for longer survival for some patients. Side effects could be well controlled with steroid hormones and Na-bicarbonate.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

Chromosome aberration frequencies produced by a 70-MeV proton beam.

The effectiveness of a 70-MeV proton beam in the induction of chromosome aberrations was studied. We employed peripheral lymphocytes and analyzed the frequencies of dicentrics and rings after irradiation at doses ranging from 0.1 to 8.0 Gy at various depths within a Lucite phantom. The frequency of chromosome aberrations after irradiation with an unmodulated proton beam at 5 mm showed a dose-response relationship similar to that of 60Co gamma rays. However, irradiation at greater depths with the spread-out Bragg peak induced higher aberration frequencies at doses lower than those with gamma rays. Furthermore, the distribution curve of chromosome aberration frequencies as a function of depth was found to be slightly different from the physically measured depth-dose curve. With the spread-out Bragg peak the biological effects were more marked at greater depths, resulting in a distribution of relative biological effectiveness values. The results obtained from chromosome aberration analysis may not be related directly to those for the relationship between dose and cell killing. Slight differences in values for relative biological effectiveness due to the change of dose and site of proton beam irradiation may not be important for practical proton beam therapy, but may be important in the prevention of late radiation injuries.

Adult↗
PubMed1990

[The effect of partial hepatectomy on glucose-stimulated insulin release from the isolated perfused pancreas in rats].

To investigate the functional changes of endocrine pancreas in the early stage after partial hepatectomy, we evaluated the changes in the secretion of insulin to glucose load in perfused rat pancreas at 4 and 7 days after about 70% hepatectomy. Insulin responses to glucose load were significantly augmented at 4 days compared with both the normal and sham-operation rats and at 7 days also significantly augmented compared with the normal rats. These results are in accordance with the morphological changes of islet and indicate that in the early stage after hepatectomy, the response of islet B-cells to glucose load are increased in order to support the glucose metabolism in this stage. Thus, insulin seems to play an important role in the regenerating liver after hepatectomy and these changes seem to be one of the adaptation of endocrine pancreas after hepatectomy to support the regenerating liver.

Animals↗
PubMed1990

Frequency of micronuclei in hepatocytes following X and fast-neutron irradiations--an analysis by a linear-quadratic model.

The usefulness of the micronucleus assay for investigating the radiation response of hepatocytes was examined. The frequency was defined as the ratio of the total number of micronuclei to the number of hepatocytes examined. The dose-response curves were curvilinear after X rays and linear after neutrons. These dose-response curves were analyzed by a linear-quadratic model, frequency = aD + bD2 + c. The a/b ratio was 3.03 +/- 1.26 Gy following X irradiation. This value is within the range of the alpha/beta ratios reported by others using the clonogenic assay of hepatocytes. While the a/b value for neutrons was 24.3 +/- 11.7 Gy, the maximum relative biological effectiveness of neutrons was 6.30 +/- 2.53. Since the micronucleus assay is simple and rapid, it may be a good tool for evaluating the radiation response of hepatocytes in vivo.

Animals↗
PubMed1990

[Influence of alcohol ingestion on plasma gastrin and CCK levels in human beings].

We investigated the time courses of the plasma ethanol, acetaldehyde, gastrin and cholecystokinin (CCK) levels after the ingestion of ethanol (1g/kg, 21.5%, whisky) in healthy male adult volunteers. The ethanol level reached a peak at 15 to 45 minutes after the ingestion and then decreased almost linearly. The acetaldehyde level of the group who became flushed after drinking (the F group) peaked earlier than that of the other group whose faces became only slightly flushed (the N group). The gastrin level increased significantly and remained elevated for about 3 hours. In three of the nine subjects, the CCK level increased 75 minutes after drinking. As a result, the absorption of the ingested ethanol is more rapid than 15 minutes, followed by a quick catabolism of the absorbed ethanol to acetaldehyde, but the catabolic action of acetaldehyde in the F group is later than that in the N group. The plasma gastrin level is certified to increase after the ingestion of ethanol and this is not mediated by acetaldehyde because the intra-venous infusion of acetaldehyde was not increased the plasma gastrin level in dogs. CCK which stimulate the pancreatic enzymes may be considered to have a possibility relating to the development of alcoholic acute pancreatitis but the ingestion of ethanol showed no increase of the plasma CCK level. But we cannot deny the possibility of the individual differences in the hormonal reaction in these experiments.

Acute Disease↗
PubMed1990

[Tumor control-significance of the stem cell number].

The stem cell number is one of the important factor determining tumor control radiation dose. It is now clear that 50% tumor cell doses in various rodent tumors inversely related to their tumor control radiation doses. Roles of radiation-sterilized cells on the clonogenicity of survived stem cells are controversial, and should be explored by future research. Methodological innovations are also desirable to measure the stem cell number in human tumors.

Animals↗
PubMed1990

[Effects of scopolamine and diazepam on delayed discrimination behavior in rats].

The effects of subcutaneously administered scopolamine and diazepam on simultaneous as well as delayed light-dark discrimination behavior were studied in a Y-maze situation using rats. In simultaneous discrimination behavior, running responses to the lighted side of either the right or left arm of the Y-maze were regarded as correct choices. In delayed discrimination behavior, running responses to the lighted side at several delay times (0. 2, 4, and 8 sec) after extinguishment of the light were regarded as correct choices. In the saline test, the percentage of correct choices decreased as the delay time was extended. Scopolamine at 0.03 mg/kg decreased the percentage of correct choices as the delay time was extended within the range of 0 sec through 4 sec. Diazepam both at 1 mg/kg and at 2 mg/kg decreased the percentage at the delay times of 0, 2, and 4 sec but this decreasing effect was not dependent on the delay time. The same doses of these drugs had no effect on simultaneous discrimination behavior. These results suggest that scopolamine at 0.03 mg/kg and diazepam both at 1 mg/kg and at 2 mg/kg disrupt delayed discrimination behavior in different ways.

Animals↗
PubMed1990

Comparison of different parathyroid hormone radioimmunoassays in uremic patients with secondary hyperparathyroidism.

Parathyroid hormone (PTH) levels of patients with chronic renal failure (CRF) were measured by three different radioimmunoassays (RIA); RIA for mid-region PTH by antibody CH9 (i-PTH) (1), RIA for intact fragments of PTH (intact PTH) and RIA for C-terminal fragments of PTH (PTH-C). PTH levels were higher in CRF patients undergoing hemodialysis therapy (hemodialysis patients) by all three methods. However, PTH levels measured only by i-PTH assay and intact PTH assay were significantly higher in patients with CRF who were not on dialysis (non-dialyzed CRF patients). PTH levels were above normal when creatinine clearance was below 45 ml/min in the intact PTH assay and 66 ml/min in the i-PTH assay. I-PTH levels were well correlated with the severity of osteitis fibrosa evaluated by the degree of periosteal resorption in the digits of hemodialysis patients. Since special handling of the sample is required for the intact PTH assay, i-PTH assay is the most suitable method for diagnosing secondary hyperparathyroidism in patients with CRF.

Bone Diseases, Metabolic↗
PubMed1989

[Presence of atrial natriuretic peptide in canine cerebrospinal fluid and its origin].

The purposes of the present study are to demonstrate the presence of atrial natriuretic peptide (ANP) in canine cerebrospinal fluid (CSF) and to determine its origin as either the brain or atrium. Fifty-seven mongrel canines weighing from 7.5 to 23.0kg (male: 28, female: 29) were anesthetized with sodium pentobarbital (30mg/mg, iv) and were ventilated with a Harvard respirator. 16 canines (11.5 to 16.0kg) were used to examine the effect of endogenously increased plasma ANP level on the ANP concentration of the CSF in acute heart failure induced by experimental aortic regurgitation. Subsequently to examine the effect of exogenously increased plasma ANP level on the ANP concentration of the CSF, physiological and pharmacological doses of synthetic human alpha-ANP were continuously infused into the right ventricle (25ng/kg/min. and 250ng/kg/min., respectively) for 32 min. in 15 canines (8.0 to 23.0kg), only physiological dose (25ng/kg/min.) was infused for 180 min. in 8 canines (12.5 to 23.0kg). The concentrations of ANP in canine CSF and plasma were measured by our highly sensitive and specific radioimmunoassay (RIA). The molecular forms in the plasma, CSF and the atrium and hypothalamus tissues were determined by gel permeation chromatography (GPC). The ANP concentration in CSF was 2.8 +/- 1.2pg/ml (mean +/- SD), lower than that in the plasma which was 51.5 +/- 19.9pg/ml, and no correlation was found between them (r = 0.16, p = ns). Plasma ANP concentrations increased from 46.5 +/- 13.0pg/ml to 94.6 +/- 27.7pg/ml according to a rise of the left atrial pressure by experimental aortic regurgitation. However, no significant change was noted from 3.7 +/- 0.7pg/ml to 3.8 +/- 1.0pg/ml in CSF ANP concentrations during the aortic regurgitation. The ANP concentration in the CSF did not change significantly while the plasma ANP concentration greatly increased following each intravenous infusion of the synthetic alpha-ANP. Only a single peak corresponding to a low molecular weight form of ANP in the position of authentic alpha-ANP in the canine CSF was observed by GPC, while there were peaks for both low and high molecular forms of ANP in the canine plasma. Furthermore, both low and high molecular weight peaks were observed for the right atrium and hypothalamus tissue extracts by GPC, and those tissues of the right atrium and hypothalamus contained ANP concentrations of 1.97ng/mg wet tissue and 2.6pg/ml wet tissue, respectively. These results indicate the presence of ANP in canine CSF and that it does not come from blood that has seeped across the blood-CSF barriers but may originate in the brain.

Animals↗
PubMed1989

Brain natriuretic peptide-like immunoreactivity is present in human plasma.

A highly specific and sensitive radioimmunoassay (RIA) for a novel porcine brain natriuretic peptide (BNP) has been established to elucidate whether BNP-like immunoreactivity (LI) is present in human plasma. The antibody used was specific for BNP without any crossreactivities with known human atrial natriuretic peptides (hANP). After extraction of human plasma with Sep-Pak cartridge, this assay allowed for detection of BNP-LI as low as 0.1 fmol/tube. In 12 healthy subjects, the mean concentrations of plasma BNP-LI were 1.5 fmol/ml. Reverse-phase HPLC coupled with BNP RIA revealed that the single major component with BNP-LI, corresponding to porcine BNP(1 26), was apparently distinct from that of alpha-hANP. These data indicate that a small molecular mass form with BNP-LI circulates in human blood.

Animals↗
PubMed1989

Structure of thiolactomycin.

[4R,(2E,5E)]-3-Hydroxy-2,4,6-trimethyl-2,5,7-octatriene-4-thiol ide, C11H14O2S, Mr = 210.30, hexagonal, P6(5), a = b = 9.8514 (6), c = 19.954 (1) A, V = 1677.1 A3, Z = 6, Dx = 1.249 g cm-3, lambda(Cu K alpha) = 1.5418 A, u = 23.07 cm-1, F(000) = 672, T = 298 K, R = 0.028 for 1021 unique reflections [Fo2 greater than 2 sigma(Fo2)]. The absolute configuration was determined by the Bijvoet method. The thiolactone ring is planar with S-C bond distances of 1.774 (3) and 1.856 (3) A, and C-S-C angle of 93.3 (1) degrees. The angle between least-squares planes for the thiolactone and butadienyl groups is 101.7 degrees.

Anti-Bacterial Agents↗
PubMed1989

Presence of immunoreactive endothelin in human plasma.

A highly specific and sensitive radioimmunoassay has been established for measurement of human endothelin (hET) in human plasma. After extraction of plasma with an octyl-silica column, this assay allowed for detection of immunoreactive (IR) hET as low as 0.2 fmol/ml. In 16 healthy subjects, the mean concentration of plasma IR-hET was 0.6 fmol/ml. Reverse-phase HPLC coupled with radioimmunoassay revealed two major IR-hET components, one corresponding to authentic hET(1-21) and another with more hydrophilicity than hET(1-21). These data indicate that ET is a circulating vasoconstrictor hormone in man.

Adult↗
PubMed1989

Angiography of right gastroepiploic artery for coronary artery bypass graft.

We describe the angiographic technique of grafting the right gastroepiploic artery to the coronary artery. With the femoral approach, our specially devised catheter was placed in the common hepatic artery or gastroduodenal artery. The gastroepiploic artery and graft to the coronary artery were visualized satisfactorily by manual injection of contrast media.

Angiography↗