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Biomedical subjects

H Chiba

Publications and source records attributed to H Chiba.

At least 199 records · Page 11Linked to original sources
PubMed1991

[201Tl-reverse redistribution in a case with stunned myocardium].

A 58-year-old man was admitted to our hospital because of chest pain. Electrocardiogram showed giant negative T waves in leads I, II, III, aVl, aVf and V2 through V6. Echocardiogram showed anterior wall motion abnormality. Rest-redistribution thallium scan obtained 3 days after admission revealed reverse redistribution in antero-apical area. Coronary angiogram showed no significant stenotic lesions and left ventriculogram in chronic stage showed improvement of wall motion abnormality. Repeat thallium scan in chronic stage showed disappearance of perfusion defect in apical area. It was difficult to diagnose myocardial viability in our case with stunned myocardium because rest-redistribution thallium scan showed reverse redistribution. As the mechanism of this finding, early coronary recanalization in acute stage of the event was suspected.

Coronary Disease↗
PubMed1990

[A study of non-aromatizing androgen C10-19lyase in adrenal tissue].

The conversion of androgen to estrogen is mediated by aromatase activity, and 19-hydroxylase and C10-19lyase are seen to be involved in C19-demethylation. The present study is to demonstrate C10-19lyase activity in adrenal tissue. Fetal bovine and pig adrenal tissue homogenates were incubated with 14C-androstenedione(A) and NADPH under air. The products 14C-19-OHA, 14C-19-norA, with added carrier standard 3H-19-OHA, 3H-19-norA were separated and purified by T.L.C.. The identification of 19-norA was established by recrystallization and that of 19-OHA by C.C.D.. The 3H/14C ratios of the products 19-norA were found to be constant in repeated crystallization. The amount of 19-OHA from A in fetal adrenal tissue was 30.0nmol/h/g protein, and that of 19-norA from A was 12.59pmol/h/g protein. C10-19lyase activity from 19-OHA, calculated by the amounts of 19-norA in fetal, bovine and pig adrenal tissue, was 49.7, 3.50, 10.3pmol/h/g protein, respectively. This is the first report to demonstrate androgen C10-19lyase in human fetal adrenal tissue, and it is assumed that fetal adrenal tissue forms 19-norA via 19-OHA.

Adrenal Glands↗
PubMed1990

Expression of guinea-pig liver transglutaminase cDNA in Escherichia coli. Amino-terminal N alpha-acetyl group is not essential for catalytic function of transglutaminase.

Transglutaminases (EC 2.3.2.13) catalyze the formation of epsilon-(gamma-glutamyl)lysine cross-links and the substitution of a variety of primary amines for the gamma-carboxamide groups of protein-bound glutamine residues. These enzymes are involved in many biological phenomena. Transglutaminase reactions also have been shown to be suitable for applied enzymology. In this study, as a first step of studies to elucidate the structure/function relationship of transglutaminase, we constructed an expression plasmid, pKTG1, containing a cDNA of guinea-pig liver transglutaminase between the NcoI and PstI sites of an expression vector, pKK233-2, and produced the liver transglutaminase as an unfused protein in Escherichia coli. The purified recombinant enzyme was indistinguishable from natural liver transglutaminase in some structural properties such as molecular mass, amino acid composition, and amino- and carboxyl-terminal sequences. However, the alpha-amino group of the amino-terminal alanine residue of the recombinant transglutaminase was not acetylated as was that of the natural enzyme. Comparison of the recombinant enzyme with the natural one did not indicate significant differences in specific activity and apparent Km values for substrates in the histamine incorporation into acetyl alpha s1-casein. The sensitivity to activation by Ca2+ and the rate of catalyzed protein cross-linking were also similar between recombinant and natural transglutaminases. These results indicated that the N alpha-acetyl group in natural liver transglutaminase has not a particular role in the catalytic function of this enzyme.

Acetylation↗
PubMed1990

Sandwich enzyme-linked immunosorbent assay of rat apolipoprotein E.

A sandwich ELISA for rat apo E was developed. Blood was drawn from rats that had been administered with triamcinolone diacetate to increase apo E-rich HDL in serum. Apo E was purified from the d less than 1.225 g/ml lipoproteins, and antiserum was raised in rabbits. Diluted samples and standards were added into the wells of polystyrene microtiter plates precoated with immunoaffinity-purified IgG and incubated for 90 min. After washing, immunoaffinity-purified Fab'-horseradish peroxidase conjugate was added to each well and incubated for 90 min. The bound enzyme was assayed by a colorimetric method. Samples and standards were pretreated with 6 M guanidine. HCl to maximize the antigenic response of apo E. The sensitivity lies around 1 pg apo E, and the working range was 0.1 to 1.0 ng. All assay procedures were completed within 4-5 hr. The mean intra- and interassay coefficients of variation were 1.8 and 4.1%, respectively. Serum apo E concentrations were 21.2 +/- 2.1 and 61.3 +/- 17.0 mg/dl (mean +/- SD) for young (8-12 weeks old, n = 9) and old (36-40 weeks old, n = 16) rats, respectively. As determined by gel filtrations, most of the apo E in fasted rat serum was associated with larger HDL particles (or HDL1) and a small portion of apo E was present in a free form.

Aging↗
PubMed1990

Detection of human papillomavirus DNA in genital condylomata in women and their male partners by using in situ hybridization with digoxygenin labeled probes.

Twelve couples (12 women and their male partners) presenting genital warts were investigated in order to evaluate the sexual transmission of human papillomavirus (HPV) in mutual partners and the localization of HPV DNA. Formalin-fixed, paraffin-embedded biopsy samples of 12 vulvar condylomata, and 12 penile condylomata from male partners were analyzed for the presence of HPV DNA-6, -11, and 16/18 by using in situ hybridization with digoxygenin labeled DNA probes. HPV DNA was identified in 9 women (75%) and in 9 men (75%). HPV-6 was frequently identified, being revealed in 42% of the vulvar specimens, in 67% of the cervical specimens and 58% of the penile specimens. Seven of 9 (77%) positive couples shared the same HPV DNA, and 2 couples harbored different HPV DNA types between the partners. The signal intensity of the HPV DNA was generally strong in superficial cell layers, weak in parabasal or basal cell layers. No malignant lesions resulted from the condyloma acuminatum caused by HPV-6 or -11. There were only mild dysplasia in the both sexes.

Condylomata Acuminata↗
PubMed1990

Isolation and characterization of opioid antagonist peptides derived from human lactoferrin.

Peptides with affinity for opioid receptors were found in an artificially methyl-esterified peptic digest of human lactoferrin. Three active peptides were purified by two steps of reverse-phase high-performance liquid chromatography. Their structures were Tyr-Leu-Gly-Ser-Gly-Tyr-OCH3, Arg-Tyr-Tyr-Gly-Tyr-OCH2, and Lys-Tyr-Leu-Gly-Pro-Gln-Tyr-OCH3, which respectively correspond to the methyl esters of residues 318-323, 536-540, and 673-679 of human lactoferrin. The IC50 values of these peptides were 15, 10 and 23 microM, respectively, in a radioreceptor assay in the presence of 1 nM [3H]naloxone. In the myenteric plexus preparation of the longitudinal muscle of guinea pig ileum, the individual peptides had no opioid agonist activities, but they antagonized [Met5]enkephalin and morphiceptin when they were at a concentration of 10(-6)-10(-5) M, suggesting that these were the opioid antagonist peptides. These three opioid antagonist peptides were named lactoferroxin A, B and C, after casoxin, the opioid antagonist peptide derived from bovine kappa-casein. Concerning the antagonist activities of lactoferroxins for opioid receptor sub-types, lactoferroxin A showed preference for mu-receptors, while lactoferroxin B and C had somewhat higher degrees of preference for kappa-receptors than for mu-receptors. A study of the structure-activity relationship of the three lactoferroxins and their synthetic analogues showed that these opioid antagonist peptides derived from food protein could be expressed by the general formula XA-Tyr-XB-Tyr-OCH3. An amino acid in position XA may affect the specificity of the antagonist peptide for opioid receptor sub-types.

Amino Acid Sequence↗
PubMed1990

[Clinical study of ectopic eruption of the permanent first molars].

The purpose of this study was to investigate the etiology and characteristics of the ectopic eruption of first permanent molars. The subjects were 35 cases (27 maxilla and 8 mandible) with ectopically erupted permanent first molars, which were recognized in 24 out-patients (10 boys and 14 girls) visiting Tohoku University, Dental Hospital. The materials used for the analysis were dental casts, X-ray lateral cephalograms and panoramic radiographs, and both materials of the ectopic and normal groups were compared. The results were as follows: 1) There were no significant differences statistically between the mesio-distal crown diameters of the maxillary permanent first molar, central and lateral incisor, and all deciduous teeth in ectopic group and their mean values in Ono's and Otsubo's studies. 2) There were no significant differences as compared to all parts of the size of the dental arch in ectopic sides with those in the normal sides of same individuals at IIA and IIC of Hellman's developmental stage in dentition. 3) When the sizes of the dental arch in the ectopic group were compared with those of the normal group, the former were smaller at the distance between the mid-point and the canine mesial surface (Fig. 1-4), the ridge of the posterior region of the basal arch and most distal point of the primary second molar (Fig. 1-6) at the Hellman's dental age IIA, while the canine distance to the midline (Fig. 1-1), the dental arch perimeter from mid-point to the distal surface of primary second molar (Fig. 1-4+5), and the distance between the canine and primary second molar, div. X (Fig. 1-7) at Hellman's dental age of IIC were significantly smaller than the latter. 4) Regarding the comparison of the value of the changes in dental arch size between the ectopic group and the normal group from Hellman's dental age of IIA to IIC, the distance between the canine and primary second molar, div. X (Fig. 1-7) decreased markedly and the distance between the ridge of the posterior region of the basal arch and the most distal point of the primary second molar (Fig. 1-6) increased. 5) Results of the analysis of X-ray lateral cephalograms showed that the angle of eruption of first molars in the ectopic group was significantly smaller compared with normal group. 6) According to the cluster analysis on the calcification of tooth germ using panoramic radiographs, similarity among all of the samples was lacking in the ectopic group, especially congenital missing of the second molars and second premolars in the ectopic side and the delayed calcification of the ectopically erupted teeth were found in maxilla.

Child↗
PubMed1990

[Changes of the arch form and occlusion of the deciduous open bite cases: a longitudinal study].

The purpose of this study was to determine the characteristics and longitudinal changes of the arch morphology and occulusion of the deciduous open bite cases. The materials used in this study were the serial plaster casts of 40 Japanese children with deciduous open bite, and they were measured with the three dimentional system. The following results were obtained: 1. The form of dental arch with open bite in the early primary dentition changed remarkably in the maxilla but little in the mandible. In children with open bite, the maxillary intercanine distance was narrower, the maxillary arch length was longer, the palatal height of the front area was higher, but the back one was lower, and the upper central primary incisors were located more forward and upward higher than in children without open bite. 2. In the late primary dentition, the dental arch shape in the spontaneous closure group showed little difference from the control group. However the deciduous upper central incisors of the spontaneous closure group were very remarkably inclined to the palatal side, and the vertical over-jet was larger than that in the control group. The larger the horizontal over-jets were in the early deciduous dentition, the larger the vertical over-jet changed in the late deciduous dentition. 3. In the spontaneous closure group, the point of the dental arch showed a regular changing aspect, in which place marked variation was recognized in the early deciduous dentition as compared with the control group. Because of spontaneous closure, the dental arch shape approached the one of control group rapidly. 4. The result of multivariate analysis indicate that not only discontinuance of thumb-sucking but also many variables of the dental arch shape and occlusal condition may induce spontaneous closure of the open bite within the deciduous dentition term.

Child↗
PubMed1990

[Study on prognosis of threatened abortion assessed by multivariate analysis].

The serum concentrations of various hormones which included hPL, progesterone(P), estradiol(E2) and 17 alpha-hydroxyprogesterone (17P) in serum, and hCG in urine were measured simultaneously in patients with threatened abortion to evaluate the prognosis. Ultrasound scanning was also undertaken. One hundred and thirty-six patients at 5 to 8 weeks of gestation were divided into two groups retrospectively. Group A consisted of 99 patients with a good prognosis and group B consisted of 37 patients who aborted spontaneously. The mean concentrations of hormones, and ultrasound findings (GS, CRL and FHM) were not significantly different in both groups at 5 weeks. An attempt was made to apply the data to the computation in multivariate analysis. By discriminant analysis, 100% reliability was achieved in separating the two groups according to hormone levels only at this stage of pregnancy. At 6 weeks, the hCG, P and E2 values were statistically higher in group A than B. Because of the overlapping of the data, principal component analysis was attempted. Two groups were roughly separated. The values for factor loading indicated that GS, CRL and 17P effective in making the separation possible. At 7 and 8 weeks of gestation, the mean concentrations of hCG, hPL, P and E2 were significantly higher in A than B. The factor loading values indicated that ultrasound findings were essential in separating into two groups. These results suggested that hormonal analysis may be useful in assessing the prognosis in threatened abortion in the early stage of gestation (5 and 6 weeks), while ultrasound findings make an accurate prediction for the prognosis possible after 7 weeks of gestation.

Abortion, Threatened↗
PubMed1989

[Correlation between the levels of catecholamines (noradrenaline, adrenaline) and adrenal steroids (DHA-S, cortisol) in maternal and fetal blood during pregnancy and labor].

It is known that both catecholamines (CA) and cortisol (F) levels elevate during labor. To determine the correlation between adrenal steroids and medullary function, maternal blood was collected during pregnancy, first stage of labor (MVI) and at delivery (MVII). Umbilical arterial and venous blood (UA, UV) was also obtained at delivery. Further, ACTH or dexamethasone (Dx) was given during the first stage of labor, and maternal blood was collected before and 30 minutes after the administration. Plasma levels of CA[noradrenaline (NA), adrenaline (Ad)] were extracted by trihydroxyindole method and were measured by HPLC. DHA-S and F levels were determined by specific RIA. Results are as follows: 1. No apparent change was observed in maternal NA and Ad levels throughout pregnancy. DHA-S levels were high in first trimester and decreased as pregnancy advanced, while F levels showed an increase trend as pregnancy progressed. 2. All hormone levels in maternal blood increased remarkably during labor. A significant negative correlation between F and Ad levels at delivery was noted. When F levels were elevated by ACTH administration, Ad levels decreased. Ad levels elevated when F levels were suppressed by Dx administration. 3. NA, Ad and DHA-S levels in cord blood were higher than those in MVII. Levels of F in maternal blood were higher than those in cord blood. A significant correlation of F in MVII and UA was observed. These results indicate that the suppressive effect of F may be involved in the mechanism of Ad secretion, though the secretion of Ad increased with F in the course of labor. The response of fetal adrenal to the stress of labor may be different from that of maternal adrenal since a significant correlation was not noticed between the levels of Ad and cortisol in cord blood as was found in maternal blood.

Adrenocorticotropic Hormone↗
PubMed1989

Determination of amino- and carboxyl-terminal sequences of guinea pig liver transglutaminase: evidence for amino-terminal processing.

Transglutaminases (EC 2.3.2.13) catalyze the formation of epsilon-(gamma-glutamyl)lysine cross-links and the substitution of a variety of primary amines for the gamma-carboxamide groups of protein-bound glutaminyl residues. These enzymes are involved in many biological phenomena. In this study, the amino- and carboxyl-terminal sequences of guinea pig liver transglutaminase were identified by sequence analysis to determine whether this enzyme is processed posttranslationally at its terminal regions. Two peptides, believed to contain the amino-terminal sequences of transglutaminase, were isolated from the Pronase digest of the enzyme protein with SP-Sephadex C-25 column chromatography and reverse-phase HPLC. Analyses (amino acid analysis, sequencing after the treatment with an acylamino-acid-releasing enzyme, and fast atom bombardment mass spectrometry) of these peptides indicated that the amino-terminal structure of this enzyme is acetylAla-Glu-Asp-Leu-Ile-Leu-Glu. The candidate for the carboxyl-terminal peptide in the trypsin digest of enzyme was isolated from the unadsorbed fraction of affinity chromatography with anhydrotrypsin agarose gel. The peptide was found to be Asn-Val-Ile-Ile-Gly-Pro-Ala. Both the terminal sequences were completely consistent with those predicted from the cDNA sequence [Ikura, K., Nasu, T., Yokota, H., Tsuchiya, Y., Sasaki, R., & Chiba, H. (1988) Biochemistry 27, 2898-2905]. These results indicated that the amino-terminal processing occurred after or in the course of translation of this enzyme, namely, removal of the initiator methionine and a subsequent acetylation of the alanine residue adjacent to the methionine. Our results did not indicate carboxyl-terminal processing of guinea pig liver transglutaminase.

Amino Acid Sequence↗
PubMed1989

Opioid antagonist peptides derived from kappa-casein.

Opioid antagonists were sought in the fragments of kappa-casein which were obtained by chemical synthesis and enzymic digestion. A synthetic bovine kappa-casein peptide (35-41), Tyr-Pro-Ser-Tyr-Gly-Leu-Asn (casoxin A) showed opioid antagonist activity at 200 microM in the guinea pig ileum assay. A synthetic peptide Tyr-Pro-Tyr-Tyr (casoxin B) which is found in bovine and human kappa-casein, also showed opioid antagonist activity at 100 microM. Another opioid antagonist peptide (casoxin C) was isolated from tryptic digests of bovine kappa-casein by reverse-phase HPLC. The structure of the peptide was Tyr-Ile-Pro-Ile-Gln-Tyr-Val-Leu-Ser-Arg, which corresponded to kappa-casein (25-34). Casoxin C was active at 5 microM in the guinea pig ileum assay. Thus, bovine kappa-casein contains three potential opioid antagonist sequences.

Amino Acid Sequence↗
PubMed1989

Phosphorylation of casein components by tyrosine-specific protein kinases.

The phosphorylation of different caseins by a number of tyrosine-specific kinases has been studied. The different kinases showed a range of specificities, suggesting differences in recognition mechanisms. The site of phosphorylation of alpha s2-casein by one phosphorylase has been identified, and compared with analogous sites in other proteins.

Caseins↗
PubMed1989

Application of inclusion chromatography to the determination of in vitro metabolites of estriol.

The application of inclusion chromatography with beta-cyclodextrin as a mobile phase additive in high-performance liquid chromatography to the determination of in vitro metabolites of estriol is reported. Compared to conventional methods, the inclusion chromatography gives much more satisfactory separation of isomeric estriol derivatives in a short time. Species difference (rat and guinea pig liver homogenates) is observed in the glucuronidation of estriol. The hydroxylation of estriol with rat liver homogenate occurs preferentially at the 2-position. Methylation of this product with catechol-O-methyl transferase in rat liver gives almost equal amounts of 2- and 3-methyl ethers. In contrast, 4-hydroxyestriol gives 4-methyl ether as a main product.

Animals↗
PubMed1989

Characterization and use of monoclonal antibodies directed against human erythropoietin that recognize different antigenic determinants.

We have established four hybridoma cells that produce monoclonal antibodies (MoAbs) R2, R4, R6, and R12 directed toward recombinant human erythropoietin (rHuEPO). MoAbs R2, R4, and R6 bound to EPO with high affinities (kd = approximately 2, 4, and 1 nmol/L, respectively) but MoAb R12 had a low affinity (240 nmol/L). These antibodies inhibited the biological activity of rHuEPO and EPOs from humans, rats, mice, and rabbits. This inhibition was due to the blocking of EPO binding to the target cells. The fully deglycosylated rHuEPO bound to the MoAbs, indicating that they recognized peptide sequences of the antigen but not the carbohydrates attached to the antigen. An immunosorbent column with the immobilized MoAb R2 was effective for the rapid purification of EPO. MoAb R6 bound to EPO at a site(s) different from those to which other MoAbs bound. Based on this finding, a sensitive and rapid enzyme-linked immunosorbent assay of EPO, in which EPO was sandwiched between two MoAbs (R2 and R6), was developed. The assay measured plasma levels of EPO as low as 5 mU/mL within several hours.

Animals↗
PubMed1989

[Changes in 13,14-dihydro-15-keto-prostaglandin F2 alpha and dehydroepiandrosterone-sulfate (DHA-S) levels in amniotic fluid and maternal peripheral venous blood in late pregnancy and during labor].

To study the role of prostaglandin (PG) and steroids on the mechanism of parturition, levels of 13,14-dihydro-15-keto-prostaglandin F2 alpha (dhk.PGF2 alpha) and dehydroepiandrosterone-sulfate (DHA-S) in amniotic fluid and plasma during late pregnancy, labor, and puerperium, were measured by radioimmunoassay and gas chromatography-mass spectrometry. Seven patients at term were selected for this study and labor was induced by amniotomy. Amniotic fluid and maternal peripheral blood were obtained simultaneously from each individual at A) the artificial rupture of the membranes before the onset of labor, B) the onset of labor, C) the second stage of labor, D) the delivery, and E) 2 hours postpartum. No increase in either amniotic fluid or plasma dhk-PGF2 alpha was noticed when compared before and at the onset labor. However, there was a steady increase during labor and the maximum was reached at delivery. The dhk-PGF2 alpha concentration in amniotic fluid correlated well with that in maternal plasma. A similar pattern was observed in the DHA-S levels both in amniotic fluid and plasma. No apparent change was observed before the onset of labor, but there was a tendency to increase during labor. A significant correlation between the levels of dhk.PGF2 alpha and DHA-S in amniotic fluid was noticed. From the results obtained above, it is suggested that PG and DHA-S may be involved not in the initiation of labor but in the promotion of parturition. The biological significance of DHA-S on PG levels remains to be clarified.

Amniotic Fluid↗
PubMed1989

[Detection of multivessel disease in patients with myocardial infarct using exercise myocardial scintigraphy--usefulness of SPECT with qualitative and quantitative analysis].

The detection of multivessel disease (MVD) in patients with myocardial infarction (MI) was performed using exercise myocardial scintigraphy with qualitative and quantitative analysis, to compare the diagnostic ability of planar (PL), planar + washout rate (PL + WR), SPECT, Bull's eye + WR (BE + WR) and SPECT + BE + WR. Forty seven patients of anterior MI (SVD: DVD: TVD = 29: 8: 10) and thirty four patients of infero-posterior MI (SVD: DVD: TVD = 16: 8: 10) were reviewed. SPECT was superior to PL to detect ischemia of RCA in patients with anterior MI (50% vs. 100%) and to detect ischemia of diagonal branch in patients with infero-posterior MI (0% vs. 83%). The detection of ischemia of LCX in patients with anterior MI revealed low sensitivity in both PL and SPECT. SPECT + BE + WR showed the highest diagnostic ability to detect MVD in patients with both anterior (87%) and infero-posterior MI (82%). We conclude that SPECT with qualitative and quantitative analysis is the most useful to detect MVD in patients with MI.

Adult↗