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Biomedical subjects

K Fukui

Publications and source records attributed to K Fukui.

At least 307 records · Page 17Linked to original sources
PubMed1990

Nephrogenous cyclic GMP production during NaCl loading and ANP infusion.

To further study the mechanisms of the renal effects of ANP, we examined the effects of NaCl loading and ANP infusion on nephrogenous cGMP production. Six normotensives (NTs) and 7 essential hypertensives (HTs) were placed on 7-day low (3 g/day) and then 7-day high NaCl diets (20 g/day). On the last day of each period, the natriuretic and nephrogenous cGMP responses to ANP infusion at 25 ng/kg/min for 40 min were determined. ANP infusion markedly increased the plasma concentrations of ANP and cGMP and the urinary excretions of Na and cGMP. These changes were accompanied by a rise in nephrogenous cGMP. Increases in nephrogenous cGMP during ANP infusion were not different between HTs and NTs despite a greater natriuretic response in HTs. NaCl loading significantly increased the natriuretic response to ANP infusion in both groups. However, nephrogenous cGMP production induced by ANP infusion was not affected by changes in NaCl intake. Thus, although ANP-induced natriuresis is associated with an increase in nephrogenous cGMP, the natriuretic effect of ANP seems to be modified to a greater extent by indirect mechanisms such as renal perfusion pressure and body fluid volume status.

Adult↗
PubMed1990

[Choroid plexus involvement in malignant lymphoma. Case report].

Involvement of the choroid plexus by malignant lymphoma is rare. This case showed mass lesions at the choroid plexus in the first stage of systemic non-Hodgkin's malignant lymphoma. A 53-year-old female was admitted with headache, diplopia, and gait disturbance. The patient was alert but had left supraclavicular and axially lymph node swelling. Computed tomography scan revealed enhanced masses at the lateral and fourth ventricles. The lymph node biopsy disclosed non-Hodgkin's malignant lymphoma, diffuse large cell type. The immunological marker was the B-cell type. At surgery, there was highly vascular white tumor at the choroid plexus of the right lateral ventricle. The tumor also involved adjacent brain tissue. Pathological examination revealed infiltration of lymphoma cells to the choroid plexus. The subependymal and perivascular spaces of the choroid plexus were filled with lymphoma cells. Virchow-Robin space and white matter of adjacent brain tissue were also involved by lymphoma. After surgery, whole brain irradiation of 35 Gy and chemotherapy were performed. However, 14 months after initial diagnosis, the patient expired because of systemic involvement by the lymphoma.

Cerebral Ventricle Neoplasms↗
PubMed1990

[Effects of oxygen on growth of Streptococcus mutans].

Effects of oxygen on growth of Streptococcus mutans Ingbritt (serotype c) were examined. The strain could be passaged under aerobic conditions at 37 degrees C in a peptone/yeast extract medium containing 0.2% glucose. Although the growth rate was slightly retarded under aerobic conditions (the doubling time, 60 min; 45 min under anaerobic conditions), the increment of cellular dry weight change was 35 g per mole of glucose under both conditions. To investigate such aerotolerance in growth as indicated by these results, oxygen metabolism was compared between aerobically and anaerobically grown cells. No difference was observed in the apparent rate of superoxide production or superoxide dismutation. However, aerobically grown cells showed a higher activity of hydrogen peroxide reduction with glucose as substrate and accumulated a lower level of hydrogen peroxide when incubated with glucose under aerobic conditions. In addition, hydrogen peroxide added to the medium was less inhibitory to anaerobic growth when aerobic cells were used as the inoculum. These results indicate that aerotolerance of S. mutans Ingbritt can be ascribed at least in part to its hydrogen peroxide reducing activity which is elevated under aerobic conditions.

Hydrogen Peroxide↗
PubMed1990

Enzyme immunoassay and monoclonal antibodies for immunological studies of the mutans group of streptococci.

Monoclonal antibodies (MAbs) were prepared from myeloma cells and splenocytes of mice immunized with Streptococcus cricetus HS1 or Streptococcus downei MF25 cells. Various makes of immunoplates were coated with whole cells or purified polysaccharide antigens of oral streptococcal strains and tested for reactivity in enzyme immunoassay (EIA) using the Mabs. It was revealed that different immunoplates had different reactivities. It was also shown that the EIA system and MAbs were useful for the immunological study and identification of oral streptococci.

Antibodies, Monoclonal↗
PubMed1990

Cognition of alterations on a facial form corrected by orthognathic surgery.

The purpose of this study was to investigate observer's cognition of alterations on a facial form corrected by orthognathic surgery. Subjects were twenty undergraduate students at a women's college, who had no technical training in dentistry before. The subjects ranged in age from 19 to 22. The computerized analytic system was used for the fixation points analysis of eye movement. Two test cards (55 x 65cm) were used as stimuli; one test card bearing two frontal facial photographs of a patient, preoperative and postoperative, the other test card bearing two lateral facial photographs of the same patient likewise. The patient showed asymmetrical mandibular prognathism, corrected by Obwegeser-Dal Pont osteotomy and Le Fort I osteotomy. Each subject's eye movement was analyzed for 10 seconds during presentation of each stimulus. Fixation points, characteristic points and saccadic eye movements were used as indices. Subjects' introspective comments showed that 70 percent (same person-a brother group) of the subjects recognized two faces as resembling. From eye movement analysis, it was identified that the same person-a brother group searched out precisely at areas which were corrected by orthognathic surgery. This group pointed out lips or chin as differences of facial features by the introspective comments. It was suggested that these subjects comparatively make much more of impression than different facial features themselves. It was clarified that simultaneous repositioning of maxilla and mandible maintained impression of a patient's face. In conclusion, if a dentofacial deformity of a patient's face is altered by orthognathic surgery, the similarity of the face can be maintained after the surgery.

Adult↗
PubMed1990

[The effects of atrial natriuretic peptide on urinary protein excretion in patients with renal parenchymal disease and those with diabetic mellitus].

The effects of atrial natriuretic peptide (ANP) on urinary protein excretion were examined in patients with renal parenchymal diseases (RPD, n = 18) and those with diabetes mellitus (DM, n = 12). Before and 30 min after intravenous injection of ANP (50 micrograms), urine samples were collected. ANP injection increased urinary volume and urinary sodium excretion in both groups. In RPD, urinary protein excretion (UprV) increased by 87% (1.5 +/- 0.7 [SEM] to 2.8 +/- 1.1 mg/min, p less than 0.05). ANP also increased UprV in patients with diabetic nephropathy [N(+); 1.7 +/- 0.8 to 5.0 +/- 2.5 mg/min, p less than 0.05] and those without nephropathy [N(-); 0.10 +/- 0.02 to 0.22 +/- 0.07 mg/min, p less than 0.05]. Since ANP increased creatinin clearance in both groups (+9.4 +/- 2.5 ml/min in RPD and +24.1 +/- 3.5 ml/min in DM, p less than 0.01 for both), urinary protein to creatinine excretion ratios (UprV/UcrV) were determined, which should be a parameter of glomerular protein permeability. The UprV/UcrV ratio increased by 48% (p less than 0.01) and 24% (p less than 0.05) in RPD and in DM, respectively. ANP did not change urinary composition of albumin and globulin. In RPD, increases in UprV by ANP were positively related to the basal serum creatinin levels (r = 0.57, p less than 0.01). In DM group, ANP-induced increases in the UprV/UcrV ratio were higher in the N(+) subgroup than in the N(-) subgroup (+0.8 +/- 0.4 vs +0.09 +/- 0.04, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Automatic karyotyping of plant chromosomes by imaging techniques.

Chromosomes of Crepis capillaris (L.) Wallr. were analyzed using a newly developed chromosome image analyzing system, CHIAS-mini. The CHIAS-mini is a desktop system which consists of an ordinary 16-bit personal computer and an image processor as the main frames. Data acquisition, karyotyping and idiogramming of the plant chromosomes were automatically carried out with some manual interaction. The data obtained were comparable to those obtained manually and by a standard image analyzer already developed.

Computers, Mainframe↗
PubMed1989

Expression of normal and abnormal porcine kidney D-amino acid oxidase in Escherichia coli: purification and characterization of the enzymes.

Expression plasmids for normal and abnormal porcine D-amino acid oxidases (E.C. 1.4.3.3, DAO) have been constructed from cloned cDNA that encodes the entire protein sequence of DAO, and the enzymes were expressed in Escherichia coli cells on a large scale. The expressed enzymes were purified to apparent homogeneity. The molecular weight of the normal DAO (38 kD) was identical with that of DAO purified from porcine kidney, whereas that of the abnormal DAO was 39 kD, which comprised the normal DAO with an additional decapeptide at its amino terminus. However, the specific activities of the two enzymes were comparable with that of natural DAO. The results indicate that the bulky decapeptide does not affect the structure necessary for the catalytic function of DAO in the amino-terminal region. The use of a GTG triplet in the 5'-untranslated region of DAO cDNA as the initiation codon for the synthesis of the abnormal DAO is suggested.

Amino Acid Sequence↗
PubMed1989

A comparison of competitive enzyme immunoassay and precipitin inhibition tests in the analysis of polysaccharide antigenic determinants of oral streptococci.

A rapid and convenient method of competitive enzyme immunoassay (EIA) was explored for the immunological analysis by MAbs of polysaccharide antigens prepared from the mutans group of streptococci, and optimal conditions for it were established. These included the concentrations of antigen, monoclonal antibodies (MAbs) and labelled antibody, temperature, pH and reaction time. The results were compared with those obtained by precipitin inhibition tests using the classical quantitative precipitin reaction, and they were found to be consistent with the latter method. It was concluded that the EIA system can be extended to the immunological study of polysaccharide antigens of oral streptococci using MAbs which perform poorly in precipitation reactions.

Animals↗
PubMed1989

Renal hemodynamic responses to 5-hydroxytryptamine (5-HT): involvement of the 5-HT receptor subtypes in the canine kidney.

The study was designed to define the serotonin (5-HT) receptor subtypes in the canine kidney. An intrarenal infusion of 5-HT at a dose of 5 micrograms/min in anesthetized dogs resulted in a biphasic response of renal blood flow which decreased transiently then increased above the control level during prolonged infusion. The decrease of renal blood flow was abolished by infusion of methysergide but not by ketanserin, and the subsequent increase was abolished by infusion of either ketanserin or methysergide. Terazosin, an alpha1-adrenoceptor antagonist, did not modify the renal action of 5-HT. These findings suggest that the renal blood flow response induced by 5-HT did not depend on an indirect effect via the sympathetic nervous system, the initial vasoconstriction was mediated via a 5-HT1-like receptor, and that the latter vasodilatation was mediated via a 5-HT2 receptor. The infusion of 5-HT also increased urine flow and urinary excretion of sodium. These increases were reversed by pretreatment with ketanserin and abolished by methysergide. We propose that 5-HT may exert its antidiuretic action via a 5-HT1-like receptor in the tubules but that the renal hemodynamic changes induced by 5-HT may overcome its antidiuretic action. The present results suggest the existence of a 5-HT1-like and 5-HT2 receptor in the renal vasculature and a 5-HT1-like receptor in the renal tubules.

Adrenergic alpha-Antagonists↗
PubMed1989

Directional immobilization of sodium- and potassium-activated ATPase to expose its cytoplasmic part to the liquid phase on microtiter plates by wheat germ agglutinin.

A convenient method for highly efficient and directional immobilization of intact sodium- and potassium-activated ATPase (Na,K-ATPase) using wheat germ agglutinin linked on microtiter plates was developed. Wheat germ agglutinin, which bound tightly to the beta-subunit of Na,K-ATPase and had no effect on the Na,K-ATPase activity, the potassium-activated p-nitrophenylphosphatase activity, or the inhibitory action of ouabain, was covalently linked to microtiter plates and used as an immobilizer of the enzyme. The amount of Na,K-ATPase coupled to microtiter plates in this immobilizing system was more than 10-fold greater than that used in the direct immobilizing system (O. Urayama, M. Nakao, H. Nagamune, and H. Sugiyama, (1984) Anal. Biochem. 141, 194-198). Also in this system, the cytoplasmic domain of Na,K-ATPase was exposed to the liquid phase. This technique was useful for investigating the reactivities of monoclonal antibody specific for the cytoplasmic domain of the enzyme. Moreover, because this technique was used successfully in the immobilization of periodic acid--Schiff positive staining glycoprotein 1 prepared from human erythrocytes and human alpha 2-macroglobulin, the technique should also be useful for other membrane or secreted proteins that possess N-linked sugar chains containing bisecting N-acetylglucosamine or a high amount of sialic acid.

Animals↗
PubMed1989

Captopril and hydralazine suppress atrial natriuretic peptide (ANP) gene expression in the ventricles of spontaneously hypertensive rat.

We investigated the influences of captopril (CAP) and hydralazine (HYD) on the ANP mRNA level in the hypertrophied left ventricle (LV) of spontaneously hypertensive rats (SHR). Male SHRs (16 weeks of age) were given CAP (35 mg/kg/day) or HYD (3.5 mg/kg/day) for two weeks. Both drugs reduced blood pressure by a similar magnitude. Treatment with CAP caused a reduction in the ANP mRNA level in LV by 62%, and a reduction in the weight of the LV. The ANP mRNA level in LV of the HYD-treated rats was also decreased, but only by 31%. HYD did not affect LV hypertrophy. ANP gene expression in LV of SHR might be effectively suppressed by a reduction of blood pressure and also by the concomitant attenuation of hypertrophy.

Animals↗
PubMed1989

Selective reduction of serotonin immunoreactivity in some forebrain regions of rats induced by acute methamphetamine treatment; quantitative morphometric analysis by serotonin immunocytochemistry.

The influence of acute methamphetamine treatment on serotonin-like immunoreactive axons was studied in the rat forebrain. Animals, sacrificed 90 min after i.p. injection of methamphetamine (16 mg/kg) or saline, were processed for immunocytochemistry using serotonin antiserum. The numerical density of immunoreactive boutons of terminals and varicosities was quantitatively analyzed by a computer-assisted image analyzer. Compared with the control, administration of methamphetamine caused varying degrees of reduction in the numerical density in several forebrain regions. A high decrement (over -90%) was found in deep layers of the cerebral cortex, striatum and thalamic paraventricular nucleus, while a less prominent reduction (about -50%) was seen in such regions as the suprachiasmatic nucleus and basolateral amygdaloid nucleus. Moreover, superficial layers of the cerebral cortex contained uncommon features of immunopositive axons which were characterized by intensely stained fibers with large varicosities. The results suggest that the rat forebrain contains at least two types of serotonin nerves, one very sensitive to methamphetamine and another relatively insensitive or resistant to it.

Animals↗
PubMed1989

Renal and hormonal effects of alpha 1-adrenoceptor blockade by bunazosin in essential hypertension.

The renal and hormonal effects of the alpha 1-adrenoceptor blocker bunazosin were examined in 6 patients with essential hypertension. Oral bunazosin for 4 to 12 weeks significantly decreased mean blood pressure by 10%, increased effective renal blood flow and creatinine clearance by 34% and 37%, respectively, the plasma norepinephrine concentration was elevated by 60%, and the plasma atrial natriuretic peptide level was lowered by 22%. The plasma renin activity and aldosterone concentration were unchanged. Thus, a moderate reduction in blood pressure was produced by bunazosin treatment while maintaining renal perfusion.

Administration, Oral↗
PubMed1989

Type-specific antigen of Streptococcus rattus strains (KAY1 and FA1). I. Characterization.

A serotype-specific antigen was extracted from Streptococcus rattus KAY1 strain isolated first in Japan from human dental plaque and purified on an ion exchange column to compare it chemically and immunologically with that of FA1 strain which had been examined extensively by previous workers. Antigens of both strains reacted in a double diffusion test specifically with anti-FA1 serum which had previously been demonstrated specific for the strains in the same test, agglutination reactions and/or radioimmunoassay using whole cells. After separation on a DEAE-Sephadex A-25 ion exchange column the antigen was found to be resistant to various enzymatic treatments with pronases, lipase and nucleases and produce a single precipitin band against absorbed anti-FA1 serum in immunoelectrophoresis. Chemical analysis of this antigen revealed that it composed of carbohydrate, protein and a few percentages of glycerol and phosphorus. Hapten inhibition tests between antigen and antibody showed that galactose as well as glucose were the most potent inhibitors, suggesting their involvement in the antigenic determinant. Involvement of the sugars was also supported by gas chromatographic analysis and abolishment of reactivity with antiserum after the treatment of antigens with NaIO4. Moreover, protein does not seem to be involved since after SDS-PAGE analysis an enzyme immunoassay gave a negative reaction with immunoblotted antigens.

Antigens, Bacterial↗
PubMed1989

Type-specific antigen of Streptococcus rattus strains (KAY1, FA1 and BHT). II. Ultrastructural localization.

Streptococcus rattus strains (KAY1, FA1 and BHT) were examined by electron microscopy in whole cell-mounted samples and ultrathin sections for the localization of the type-specific antigen, using specific antiserum and ferritin-labelled anti-rabbit IgG as secondary antibody. In thin sections as well as whole cell-mounted samples the antigen was observed as irregular masses over the entire surface of the cells, in particular in the septal region between cells. The localization of the antigen was also examined in thin sections of a cell wall fraction prepared by treating the whole cells with glass beads in a disintegrator. Ferritin particles were observed around the outer surface, but not as many in number as those in whole cell-mounted or sectioned samples and rarely on the inner surface of the cell wall.

Antigens, Bacterial↗