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Biomedical subjects

H Chiba

Publications and source records attributed to H Chiba.

At least 145 records · Page 8Linked to original sources
PubMed1995

Efficient production of casoxin D, a bradykinin agonist peptide derived from human casein, by Bacillus brevis.

We efficiently produced a small peptide by the host-vector system using Bacillus brevis as a host. DNA encoding the physiologically functional casoxin D, composed of seven amino acids, was ligated in tandem. An expression-secretion vector containing DNA, which codes for a fusion protein of epidermal growth factor-casoxin D pentamer, was constructed. B. brevis transformed with this plasmid produced about 0.5 g/liter of the fusion protein in the culture supernatant. The fusion protein was purified with ammonium sulfate fractionation from the supernatant and digested with two kinds of proteinases. A peptide well separated by high pressure liquid chromatography was identified as biologically active casoxin D.

Amino Acid Sequence↗
PubMed1995

[B/F separation systems in enzyme immunoassay].

Methods for bound/free (B/F) separation in enzyme immunoassay are reviewed. In liquid-phase enzyme immunoassays, double antibody methods are used in small laboratories. In solid-phase enzyme immunoassay, which is a more popular and convenient method, antibody (antigen) is usually bound to the support by physical adsorption, and B/F separation is accomplished by washing the solid phase. Covalent binding of proteins, DNA, and oligosaccharides is also possible by using chemically modified supports. Indirect binding of antibody (antigen) to the support mediated by avidin-biotin methods has several merits in comparison with direct methods and double antibody methods. The immune complex transfer method has been used for ultrasensitive assays. The use of magnetic particles as a support can accelerate the immune complex formation, and is becoming more popular in clinical laboratories. A rapid sandwich enzyme immunoassay, using a porous filter as a support, has been developed for dry chemistry.

Antigen-Antibody Complex↗
PubMed1995

[A case of malignant lymphoma arising from chronic pyothorax; usefulness of magnetic resonance imaging (MRI) for diagnosis].

A 79-year-old man had a history of pneumothorax induced to treat pulmonary tuberculosis when he was 40 years old, and of chronic pyothorax when he was 60 years old. He was admitted to our hospital because of chest pain and swelling of the right lateral chest wall. Soft tissues of the chest wall and rib had been destroyed, and a fistula had formed at the skin. The diagnosis was confirmed by examination of a biopsy specimen from the chest wall tumor. The tumor was successfully treated by radiation therapy. 67Ga scintigraphy, CT, and MRI were useful for diagnosis and follow up. Pyothorax and the tumor could be distinguished only with MRI.

Aged↗
PubMed1994

Two human homologues of Saccharomyces cerevisiae SWI2/SNF2 and Drosophila brahma are transcriptional coactivators cooperating with the estrogen receptor and the retinoic acid receptor.

A set of genes (SWI1, SWI2/SNF2, SWI3, SNF5 and SNF6) in Saccharomyces cerevisiae are required for transcription of a variety of yeast genes. It was recently reported that the mammalian glucocorticoid receptor failed to activate transcription when transiently expressed in swi1-, swi2- or swi3- yeast strains. We report here that two highly related human cDNAs, hSNF2 alpha and -beta, encode amino acid sequences homologous to both the yeast SWI2/SNF2 and the Drosophila brahma. Similar to their yeast and Drosophila counterparts, both human cDNAs contain helicase motifs, a bromodomain, a highly charged C-terminal sequence and an N-terminal sequence rich in proline, glutamine and glycine. Tissue distribution of the mRNAs varied slightly. Transcriptional activation by the estrogen receptor and the retinoic acid receptor was enhanced by co-expression of either hSNF2 cDNA. No enhancement was observed for promoters which do not respond to nuclear receptors. We suggest that global transcriptional coactivators equivalent to the yeast SWI/SNF complex exist in mammalian cells.

Adenosine Triphosphatases↗
PubMed1994

Monoclonal antibodies specific for 18-hydroxycortisol and their use in an enzyme immunoassay for human urinary 18-hydroxycortisol for diagnosis of primary aldosteronism.

We report the development of a monoclonal antibody-based enzyme immunoassay (EIA) specific for human urinary 18-hydroxycortisol, a biological marker of primary aldosteronism. Hybrid cell lines (hybridomas) were isolated after fusion between myeloma cells and spleen cells prepared from mice immunized with 18-hydroxycortisol conjugate. A competitive EIA suitable for the measurement of urinary 18-hydroxycortisol was developed using the mouse monoclonal antibody, KTM-41, which showed no practical cross-reaction with related endogenous steroids and synthetic steroids. This EIA meets all the requirements of routine clinical assay in terms of sensitivity (detection limit: 20 nmol/L), reproducibility (total CV: 8-15%), accuracy (recovery: 88-115%), simplicity and rapidity (< 3 h). Urinary 18-hydroxycortisol measured by the present assay was 153 +/- 119 nmol/L (mean +/- SD, range, 28-485) and 1787 +/- 1180 (range, 810-4264) in normal subjects (n = 20) and in patients with primary aldosteronism (n = 7), respectively. Clinical validation of the assay was confirmed by an appropriate decrease in urinary 18-hydroxycortisol level in patients with primary aldosteronism subsequent to adrenalectomy: 171 +/- 141 nmol/L (range, 41-466).

Animals↗
PubMed1994

Smooth pursuit eye movements and express saccades in schizophrenic patients.

Abnormalities of saccades such as disinhibition have been hypothesized as one cause of smooth pursuit eye movement (SPEM) dysfunctions in schizophrenia. Thus, we studied saccadic eye movements in schizophrenics with SPEM dysfunction. Subjects were divided into three groups: 10 normal control subjects, 10 schizophrenic subjects without SPEM dysfunction and 10 schizophrenic subjects with SPEM dysfunction characterized by a cogwheel appearance. Visually guided saccades in gap and overlap paradigms (Saslow, 1967) were examined and saccadic reaction times (SRTs) were measured in all subjects. Only schizophrenics with SPEM dysfunctions tended to manifest excessive reflexive saccades, named express saccades (Fischer, 1987), in the gap paradigm. Moreover, most of them were also found to have express saccades in the overlap paradigm, whereas normal subjects and schizophrenic subjects without SPEM dysfunction did not show such phenomena under the same conditions. In particular, most express saccades in the overlap paradigm in schizophrenics with SPEM dysfunction, were found in movements to the right.

Adult↗
PubMed1994

Smooth pursuit eye movements and voluntary control of saccades in the antisaccade task in schizophrenic patients.

It has been hypothesized that a saccade control dysfunction is one cause of a smooth pursuit eye movement (SPEM) dysfunction in schizophrenia. We studied the voluntary control of saccades in schizophrenic patients with the SPEM dysfunction using an antisaccade task. The mean error rate in the antisaccade task was significantly higher in the two schizophrenic groups with and without a SPEM dysfunction than in the normal control group. Furthermore, the schizophrenic group with the SPEM dysfunction showed significantly more errors than the schizophrenic group without the SPEM dysfunction. These findings seem to suggest a close relationship between the SPEM dysfunction and the appearance of errors which indicates an inability to inhibit reflexive saccades voluntarily in the antisaccade task. However, 4 of 10 subjects with the SPEM dysfunction showed an error rate less than the mean error rate of the schizophrenic group without the SPEM dysfunction. So, a voluntary control disorder of saccades as the main cause of the SPEM dysfunction appeared to be unlikely. An interesting finding of this study was that many schizophrenic subjects with the SPEM dysfunction showed errors with the latencies similar to those in express saccades, particularly in the rightward direction. This finding may suggest a close relationship between the SPEM dysfunction in schizophrenic patients and some pathological conditions of express saccades such as disinhibition of express saccades.

Adult↗
PubMed1994

Cholesteryl ester transfer protein gene: two common mutations and their effect on plasma high-density lipoprotein cholesterol content.

Cholesteryl ester transfer protein regulates high-density lipoprotein cholesterol (HDL-C) level, and genetic deficiency causes hyperalphalipoproteinemia (HALP). The G to A mutation in the intron 14 splice donor (I14A) has been known to be a common mutation in HALP. Recently, another mutant, D442G (Asp 442 to Gly), was ascertained. The allelic frequencies of I14A and D442G were investigated using 226 unrelated patients with HDL-C of 1.03 mmol/L (40 mg/dL) or greater. Of these, 44 had a mutation I14A and/or D442G. The I14A was found in 15, including 4 compound heterozygotes (I14A/D442G) in patients with HDL-C of 2.05 mmol/L (80 mg/dL) or greater. All I14A homozygotes (n = 5) were present in the group with HDL-C of 3.08 mmol/L (120 mg/dL) or greater, and the allelic frequency paralleled the increase in HDL-C level. D442G was identified in 33, including the 4 compound heterozygotes. Its allelic frequency appeared as two clusters, one at HDL-C around 1.79-2.03 mmol/L (70-79 mg/dL) and the other at HDL-C of 2.82 mmol/L (110 mg/dL) or greater; the latter consisted exclusively of compound heterozygotes. Allelic frequency in the general population for I14A and D442G was 0.81% and 4.62%, respectively. These data suggest that D442G is a common mutation and that, although I14A is responsible for the most severe HALP, D442G leads to a relatively smaller increase in HDL-C.

Adult↗
PubMed1994

Rapid appearance of connexin 26-positive gap junctions in centrilobular hepatocytes without induction of mRNA and protein synthesis in isolated perfused liver of female rat.

In the adult rat liver, the gap junction protein connexin 32 (Cx32) is evenly distributed in hepatocytes within the liver lobules, while connexin 26 (Cx26) is preferentially localized in hepatocytes in periportal zones. We report here that Cx26-positive gap junctions rapidly appear in the centrilobular hepatocytes of adult female rat livers during a 30 minute perfusion of the liver through the hepatic portal vein with a 1:1 mixture of Dulbecco's modified Eagle's medium (DMEM) and oxygen transport FC-43 fluid at a physiological flow rate without any changes in the distribution of Cx32. The change in the localization of Cx26 was closely related to that of E-cadherin, and there was no significant increase in the amounts of Cx26 protein and mRNA. The appearance of Cx26 in the centrilobular hepatocytes was inhibited by treatment with cytoskeleton disruptors such as colchicine and cytochalasin B, and intracytoplasmic transport inhibitors such as brefeldin A. The liver perfusion induced the appearance of Cx26 in the centrilobular hepatocytes only in female rats. Estrogen treatment of ovariectomized rats caused the appearance of both Cx26 and E-cadherin in centrilobular hepatocytes not only in the perfused liver but also in the non-perfused liver. Our results indicate that in the rat liver: (a) the localization of Cx26 can be modulated by a post-translational mechanism; (b) E-cadherin may play an important role in the formation of gap junctions composed of Cx26; and (c) the formation of gap junctions is regulated by female steroid hormones.

Animals↗
PubMed1994

Cellular polarity correlates with vimentin distribution, but not to keratin, in human renal cell carcinoma cells in vitro.

To investigate the relationships among vimentin, keratin and cellular polarity, reorganized glands composed of renal cell carcinoma cells were investigated in vitro. We employed two different three-dimensional collagen gel culture methods, the "floating sandwich method (FSM)" and the "dispersed embedding method (DEM)." The cells composed of reorganized glands formed by FSM culture showed distinct polarity. In contrast, the cellular polarity of the cells formed by DEM culture was less distinct. Keratin was evenly distributed throughout the cytoplasm regardless of the culture method. In contrast, in reorganized glands obtained by FSM culture, vimentin was distinctly polarized at the basal pole while glands obtained by DEM culture showed random distribution of vimentin. These results suggest that there is a close relationship between cell polarity and intracellular localization of vimentin, and that there may be different mechanisms controlling the organization of the two intermediate filament (IF) networks.

Carcinoma, Renal Cell↗
PubMed1994

Hormonal regulation of connexin 43 expression and gap junctional communication in human osteoblastic cells.

We have recently shown that connexin 43 (Cx43), a major gap junction protein in osteoblasts, is expressed with an increase in cell density (CHIBA, H. et al. (1993). Cell Struc. Funct., 18: 419-426). In the present study, we examined what kinds of hormones and cytokines regulate the gap junction protein in osteoblastic cells, using a human osteoblastic cell line (SV-HFO) after reaching a confluent density to avoid influence of cell proliferation. Either retinoic acid (RA) or transforming growth factor-beta 1 (TGF-beta 1) induced the Cx43 expression of SV-HFO cells, as revealed by Northern blot analysis and immunocytochemistry. These modulators also increased gap junctional intercellular communication, in terms of the extent of dye transfer. On the other hand, 1 alpha, 25-dihydroxyvitamin D3 did not influence the Cx43 expression and gap junctional intercellular communication of the cells. These results suggest that RA and TGF-beta might maintain bone tissue as an organized tissue in vivo by increasing intercellular communication of osteoblastic cells.

Calcitriol↗
PubMed1994

Biochemical significance of 19-hydroxytestosterone in the process of aromatization in human corpus luteum.

19-Hydroxyandrogens are known to be an intermediary metabolite in the aromatizing reaction, though the physiological role of this compound has not yet been clarified. In this study, microsomes obtained from human corpus luteum were incubated with testosterone or 19-hydroxytestosterone (19-OHT) as the substrate to investigate the biochemical significance of 19-OHT in the process of aromatization in the ovary. The inhibitory effects of 4-hydroxyandrostenedione (4-OHA) on the formation of estradiol from testosterone and 19-OHT in human ovary were also investigated. When testosterone was incubated with human ovarian microsomes, 19-OHT and estradiol were identified. When 19-OHT was used as the substrate, the formation of estradiol was demonstrated. To our knowledge, this is the first report to demonstrate the formation of estradiol from 19-OHT in human ovarian tissue. The Km value of aromatase for testosterone on human corpus luteum microsomes was 0.21 microM. 4-OHA exhibited inhibition with a Ki of 35 nM. With testosterone and 19-OHT as the substrate, the formation of estradiol was also equally inhibited by 4-OHA. A dose dependent inhibition of estradiol formation was observed, with no apparent accumulation of 19-OHT. These results suggest that 19-OHT may not only be an intermediary metabolite in the aromatization of testosterone by human ovary but could be a product of the microsomal enzyme.

Adult↗
PubMed1994

A family with complete deficiency of plasma cholesteryl ester transfer protein activities.

A 43-year-old male with a high value of high density lipoprotein cholesterol (151 mg/dl) was found among subjects receiving annual health checks. We investigated the cholesteryl ester transfer protein (CETP) activity and conducted a family study. There was complete deficiency of CETP activities in the proband and his sister, and partial deficiency of CETP activities in his mother and daughter. Genetic analysis revealed a splicing defect (G to A point mutation) in intron 14 of the CETP gene.

Adult↗
PubMed1994

Study on self-recording audiogram of sudden deafness.

Self-recording audiograms of sudden deafness in 54 patients were studied for the relationship between type of Jerger's classification, hearing loss at the initial examination, and prognosis of hearing loss. Type I of Jerger's classification was shown in patients with slight to profound hearing loss, whereas Type II + IV was shown more frequently in cases with profound hearing loss. Many patients of Types I and II were among those who recovered completely or markedly, while patients of Type II + IV were found more frequently among those who recovered or had unchanged hearing.

Audiometry↗
PubMed1994

[Pharmacokinetic and clinical studies on biapenem (L-627) in the pediatric field].

Pharmacokinetic and clinical studies on biapenem (L-627), a newly developed carbapenem, were performed and the following results were obtained. 1. Absorption/excretion: Pharmacokinetics of biapenem was studied in 14 children at doses of 6 mg/kg and 12 mg/kg administered through 30 minutes-drip infusion. Peak plasma levels and plasma half-lives of the 2 doses were 22.5, 29.9 micrograms/ml, and 0.84, 0.85 hours, respectively. Their urinary recovery rates were 54.5 to 76.1% and 37.3 to 59.5%, respectively. Cerebrospinal fluid levels of biapenem in two patients with purulent meningitis were 0.88 and 2.72 micrograms/ml, and the penetration rates were 3.7 to 8.3%. 2. Clinical study: Forty-nine patients were treated with biapenem at doses exceeding 90 to 100 mg/kg/day for purulent meningitis and at doses between 15.0 and 36.0 mg/kg/day for other infections. Biapenem gave "Excellent" or "Good" responses in 48 cases, hence an efficacy rate of 98.0% was obtained. Only one patient with pneumonia showed a fair response. No adverse reactions were observed. Abnormal laboratory test results were noted in 7 patients including elevation of GOT, GPT, and eosinophils. In no cases the treatment had to be discontinued.

Absorption↗