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Biomedical subjects

Y Ohba

Publications and source records attributed to Y Ohba.

At least 163 records · Page 9Linked to original sources
PubMed1991

Determination of serum cortisol by reversed-phase liquid chromatography using precolumn sulphuric acid-ethanol fluorescence derivatization and column switching.

An assay method for serum cortisol, using precolumn sulphuric acid-ethanol fluorescence derivatization and reversed-phase liquid chromatography with a column-switching technique, has been developed. The crude precolumn fluorescence cortisol derivative was prepared by the addition of sulphuric acid to serum deproteinized with ethanol, and directly injected onto an octadecylsilane-bonded silica gel (ODS) precolumn for concentration and purification. After switching columns the samples were separated using an ODS analytical column and monitored fluorimetrically. When the pH of the mobile phase in the analytical separator decreased to 1.85, the emission wavelength of the cortisol derivative changed to 520 nm (excitation of 365 nm) and the fluorescence intensity increased. Among the sulphuric acid-ethanol derivatives of various steroids, cortisol, corticosterone and testosterone emitted fluorescence. However, their retention times differed from those of the cortisol derivatives (12.5 min). The detection limit of cortisol was 0.3 micrograms/dl (signal-to-noise ratio of 3). Use of the fully automated column-switching system contributed to good reproducibility and recovery.

Chromatography, High Pressure Liquid↗
PubMed1991

Effect of salivary epidermal growth factor on wound healing of tongue in mice.

The role of salivary epidermal growth factor (EGF) in wound healing of the tongue was studied in mice. Sialoadenectomy (removal of the submandibular glands, which are the major source of salivary EGF) or sham operation was performed 2 wk before infliction of wound on the tongue. Salivary EGF levels were 1.98 +/- 0.47 and 0.20 +/- 0.04 (SE) microgram/ml in sham-operated male and female mice, respectively, whereas sialoadenectomy reduced salivary EGF to undetectable levels in both male and female mice. A circular superficial wound measuring approximately 2 mm in diameter was made in the middle of the tongue by mechanically ablating only the epithelial layer. The rate of wound healing was monitored by a stereomicroscopy. Sialoadenectomized male mice showed a significant delay in wound healing compared with sham-operated controls. Treatment of sialoadenectomized male mice with EGF (1 microgram/ml in drinking water) restored the rate of wound healing to normal levels. Transforming growth factor (1 microgram/ml) was as effective as EGF in the promotion of wound healing, whereas nerve growth factor (1 microgram/ml) was ineffective. Essentially the same results were obtained in female mice. In addition, two classes of EGF binding sites with high and low affinity were demonstrated in the epithelium of the tongue obtained from male and female mice. The maximum binding sites and dissociation constants of the EGF receptors were the same between males and females and were not affected by sialoadenectomy. These results suggest that salivary EGF is involved in the promotion of wound healing of the tongue in both male and female mice.

Animals↗
PubMed1991

Pretranslational enhancement of epidermal growth factor receptor by direct effect of testosterone in mouse liver.

The effects of testosterone on the levels of epidermal growth factor receptor (EGFR) in mouse liver were studied. Orchiectomy resulted in 39% and 41% reductions in the levels of EGFR mRNA and EGF binding, respectively, within 2 weeks. Treatment of orchiectomized mice with a sc injection of testosterone propionate (TP; 100 micrograms/mouse.day) for 1 week restored these values to normal male levels. The hepatic levels of EGFR mRNA and EGF binding in females were 37% and 36% of those in males, respectively, and were not affected by ovariectomy, whereas treatment of females with TP (100 micrograms/mouse.day) increased EGFR to normal male levels within 1 week. On the other hand, neither orchiectomy nor androgen treatment affected levels of mRNAs for EGFR in the kidney or mRNAs for the structural protein beta-actin in the liver. To examine whether testosterone directly increased EGFR levels in the liver, TP (1.0 mg) pellets were implanted into the spleen of orchiectomized mice, so that testosterone released from the pellets reached the liver through the portal vein but did not enter the systemic circulation due to rapid clearance by the liver. The heptic levels of EGFR mRNA and EGF binding in orchiectomized mice were restored to normal male levels by intrasplenic implantation of TP (1.0 mg) pellets. This treatment also increased the hepatic levels of EGFR mRNA and EGF binding in female mice by 61% and 68%, respectively. In addition, sialoadenectomy, which reduced plasma EGF, as well as EGF antiserum treatment did not affect the androgen-dependent increase in EGFR levels in the liver, suggesting that endogenous EGF is not involved in the androgenic regulation of hepatic EGFR levels. These results suggest that hepatic EGFR levels are at least in part regulated at a pretranslational level by direct effects of androgens on the liver.

Animals↗
PubMed1991

A point mutation in C-terminal region of cdc2 kinase causes a G2-phase arrest in a mouse temperature-sensitive FM3A cell mutant.

A mouse temperature-sensitive mutant for cell growth, tsFT210, was characterized. More than 90% of the mutant cells were arrested at the G2 phase at the nonpermissive temperature (39 degrees C). In this mutant, the activity of cdc2 kinase did not increase at the nonpermissive temperature (39 degrees C) but did increase at the permissive temperature (33 degrees C) at the G2/M phase in the cell cycle. The in vitro activity of cdc2 kinase of tsFT210 was more thermolabile than that of wild-type cells. The amount of cdc2 kinase in tsFT210 cells decreased when the cells were incubated at 39 degrees C, but that in wild-type cells did not. Using the polymerase chain reaction (PCR), a point mutation in cDNA of cdc2 kinase was found in tsFT210, and as a result, the proline of wild-type cdc2 kinase at the 272 amino acid residues from N-terminal methionine changed to serine. During preparation of this paper, the detection of two mutation sites of this mutant was reported (Th'ng, J.P.H., Wright, P.S., Hamaguchi, J., Lee, M.G., Norbury, C.J., Nurse, P., and Bradbury, E.M. (1990). Cell, 63: 313-324); one was the same site as reported here, the other was A-to-G change in the 154th base from base A in initial ATG, and this caused the change of isoleucine to valine in the PSTAIR region of cdc2 kinase. This mutation in the PSTAIR region was not detected by us. The probable reason for this discrepancy was in that Th'ng and his group sequenced a cDNA cloned from the amplified cDNAs by PCR, and did not directly sequence the amplified cDNA as we did.

Amino Acid Sequence↗
PubMed1991

Influence of epidermal growth factor on liver regeneration after partial hepatectomy in mice.

The role of epidermal growth factor (EGF) in liver regeneration was studied in mice after partial hepatectomy. Two weeks before partial hepatectomy, mice were sham-operated (control) or sialoadenectomized (removal of submandibular glands) to reduce plasma EGF levels. Sialoadenectomized mice showed low plasma EGF levels (29.7 +/- 6.6 pmol/l; mean +/- S.E.M.) compared with controls (66.0 +/- 8.3 pmol/l). After partial hepatectomy, sialoadenectomized mice were treated with or without a daily s.c. injection of 5 micrograms EGF and the rate of DNA synthesis in the regenerating liver was monitored by [125I]iododeoxyuridine uptake. Control mice showed a sharp peak of DNA synthesis at 48 h after partial hepatectomy while sialoadenectomized mice showed a delayed and broad peak at 84 h. Treatment of sialoadenectomized mice with EGF (5 micrograms/mouse per day) completely restored the pattern of DNA synthesis so that a sharp peak appeared at 48 h. The total liver DNA content of the control mice (79.1 +/- 2.5% of the preoperative level; mean +/- S.E.M.) was significantly (P less than 0.01) higher than that of the sialoadenectomized mice (65.2 +/- 3.0%) 3 days after partial hepatectomy, but this difference disappeared on day 7 when liver regeneration was almost completed in both groups. Treatment of sialoadenectomized mice with EGF increased total liver DNA content (78.2 +/- 2.9%) to that of control mice on day 3 after partial hepatectomy. In addition, normal mice showed a rapid increase in plasma EGF levels at 1-8 h after partial hepatectomy, whereas sialoadenectomized mice showed low plasma EGF levels throughout the course of the experiment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

[Statistical analysis of post-stroke patients in a rehabilitation institution].

A retrospective analysis of 312 stroke patients (200 men, 112 women; average age 65) admitted to Yamaguchi Rehabilitation Hospital during the past three years showed the following results. 1) After an average period of stay of 244 days 225 patients were discharged to home, general hospitals, extended care facilities, or nursing homes. 2) The group of patients over 80 years of age at admission had a lower ratio of home returns than in other groups (p less than 0.01). 3) Patients who returned home had higher scores not only on discharge Barthel index scores but on admission Barthel index scores, compared with other discharged patients (p less than 0.01). 4) The higher the admission Barthel index score, the shorter the period of stay (p less than 0.01). Concerning discharge Barthel index scores, patients who stayed over two years had lower scores than patients who stayed less than two years (p less than 0.01). The results of this analysis suggest the importance of determining goals and programs taking admission Barthel index scores as well as other available factors into consideration for patients with stroke admitted to rehabilitation institutions.

Aged↗
PubMed1991

Control of growth and differentiation of the mammary gland by growth factors.

Mammary gland development is a complex process regulated by various steroid and polypeptide hormones. Although the systemic importance of hormones, such as estrogen, progesterone, prolactin, and growth hormone, in the growth of the mammary gland has been well documented, these hormones are virtually incapable of stimulating mammary cell growth in vitro. Thus, the growth stimuli for mammary cells requires clarification. In recent years, a number of growth factors have been discovered; this has prompted interest in examining possible involvement of these biologically active agents in the process of mammary gland development. Results presented herein indicate that several growth factors including epidermal growth factor, transforming growth factor alpha and beta, basic fibroblast growth factor, insulin-like growth factor-I, and mesenchyme-derived growth factor participate in the regulation of mammary cell growth and differentiation.

Animals↗
PubMed1991

Cyclothiazomycin, a novel polythiazole-containing peptide with renin inhibitory activity. Taxonomy, fermentation, isolation and physico-chemical characterization.

Cyclothiazomycin is a novel renin inhibitor produced by Streptomyces sp. NR0516. It was isolated from fermentation broth by extraction with butyl alcohol, QAE-Toyopearl column chromatography and preparative HPLC. Cyclothiazomycin, which was determined to be a unique polythiazole-containing bicyclic peptide, exhibited inhibitory activity against human plasma renin with IC50 being 1.7 microM.

Angiotensin I↗
PubMed1991

[An autopsy case of neoplastic angioendotheliosis mainly affecting the lung and presenting with atypical cells in peripheral blood].

Neoplastic angioendotheliosis (NAE) is a rare condition characterized by proliferation of atypical cells in small vessels of various organs. In the past, atypical cells seen in this condition were considered to originate from vascular endothelial cells. However, recent immunohistochemical studies have established that the tumor cells in this condition mainly originate from B-lymphocytes. NAE is likely to affect the central nervous system and skin. Cases of NAE with a primary lesion in the pulmonary vessels are rare. One such rare case of NAE was recently encountered by us. The patient was a 77-year-old woman who was admitted to our department because of fever and interstitial shadow in both lungs. After admission, fever did not subside, and the pulmonary shadow became more marked. Laboratory tests upon admission disclosed elevated LDH. Of isozymes, LDH2 and LDH3 were high. Anemia and thrombocytopenia gradually became aggravated, and atypical cells with large basophilic cell body and irregularly shaped nucleus subsequently appeared in peripheral blood. Thereafter, the patient's general condition worsened rapidly and she died about 5 months after admission. Post-mortem examination revealed pleomorphic atypical cells filling the lumen of small vessels in various regions of the body. This finding was particularly marked in pulmonary vessels. With various immunohistochemical stains, these cells were identified as cells of B-lymphocyte origin.

Aged↗
PubMed1991

[Humoral immunity and lymphocyte subsets in patients with dilated cardiomyopathy].

We examined immunological abnormalities in patients with dilated cardiomyopathy (DCM) and reviewed their medical histories, NYHA classifications, electrocardiogram findings and chest X-Ray findings with regard to severity of DCM. Elevated CD4/CD8 ratio as well as decreased number of CD8 cells in lymphocyte subsets was recognized. These abnormalities were particularly noted in patients with past history of myocarditis. NYHA IV class increases in CTR and left ventricular dimension, and a reduced ejection fraction. These findings suggest that lasting of myocardial damage causes immunological abnormalities and the examination of DCM patients' immunological status is useful in anticipating disease process and determining medical treatment.

Autoantibodies↗
PubMed1991

Further cases of Hb Hirosaki in two Japanese families.

Hb Hirosaki (alpha 43(CE1)Phe----Leu) was recently found anew in two Japanese families. The probands had chronic hemolytic disorders, while two other carriers of the same Hb in one family did not exhibit increased hemolysis. Hb Hirosaki comprised 5 and 2% of the total Hb in the splenectomized and non-splenectomized proband, respectively, while it comprised only 1% in the two clinically silent carriers. The expected nucleotide substitution was found in the alpha 2 (rather than alpha 1) globin gene in 1 proband. The abnormal globin was synthesized (with incorporation of [3H]-leucine) at about 30 and 20% of the total alpha-chain in reticulocytes of the probands and in those of the silent carriers, respectively. The specific radioactivity of the abnormal chain was about 20-times higher than that of the normal counterpart in the non-splenectomized patient and silent carriers (7-times in the splenectomized patient). The total alpha/beta radioactivity ratio was much higher than unity. The newly synthesized Hb Hirosaki had a slightly high isoelectric point and appeared just in front of normal Hb A in anion-exchange chromatography, but the electric charge of aged Hb Hirosaki was indistinguishable from that of Hb A. These results suggest that Hb Hirosaki is quite unstable, and is rapidly denatured and degraded after biosynthesis. The physical number of the alpha globin genes was normal in all subjects.

DNA↗
PubMed1990

The difference in murine CDC2 kinase activity between cytoplasmic and nuclear fractions during the cell cycle.

The mouse analog of yeast CDC2+ kinase was detected in the cytoplasmic and nuclear fractions of cultured mouse FM3A cells. Its activity in the nuclear fraction increased in the G2/M phase became seven times higher than that in the G1/S phase, while the activity in the cytoplasmic fraction remained was almost constant from the G1/S to G1 phases. The activity in the cytoplasmic fraction was similar to that in the nuclear fraction in the G2/M phase. The amount of the enzyme remained almost constant during the cell cycle in both the nuclear and cytoplasmic fractions. These findings suggest that the cytoplasmic enzyme might play an independent role in the cell cycle.

Amino Acid Sequence↗
PubMed1990

Determination of urinary free noradrenaline by reversed-phase high-performance liquid chromatography with on-line extraction and fluorescence derivatization.

A fully automated reversed-phase high-performance liquid chromatographic method with fluorimetric detection for the determination of urinary free noradrenaline was developed. Urine samples, diluted with buffer were injected into a boric acid gel column (12 microns, TSK: 10 x 4.6 mm I.D.) without prior extraction. Urinary noradrenaline was simultaneously extracted and derivatized with an alkaline mobile phase of pH 11, containing o-phthalaldehyde and 2-mercaptoethanol, in a boric acid gel column. After switching columns, the fluorescent derivatized catecholamines were separated with an ODS-4PW column (TSK) and a mobile phase of pH 2 and the fluorescence was monitored with excitation at 340 and emission at 440 nm. The retention times of noradrenaline and dopamine were 11.0 and 14.2 min, respectively. The detection limits for noradrenaline and dopamine were 0.2 and 20 ng, respectively. This method has the advantages of not requiring preliminary extraction of urinary catecholamines, high sensitivity and stability of o-phthalaldehyde-derivatized catecholamines.

Boric Acids↗
PubMed1990

Distribution and classification of acylphosphatase isozymes.

Distributions of acylphosphatase isozymes among organs of several animal species were investigated. Organ extracts of pig and chicken were treated with isozyme-specific antibodies, subjected to electrophoresis on a polyacrylamide gel, then the gel was stained for acylphosphatase activity. Both animals showed three activity bands; one band was named common type isozyme because of its wide distribution in testis, muscle, brain, heart, spleen, kidney, liver, and erythrocyte, and the other two bands were named muscle type isozymes because of their localization in skeletal muscle. This classification was supported by selective and quantitative reactions of the isozymes to the isozyme-specific antibodies. Because the two bands of the muscle type have the same amino acid sequence and differ only in modifications on an -SH group, it is suggested that pig and chicken have only the two major types of acylphosphatase. This conclusion was supported by similar experiments on dog, human, rabbit, and pigeon.

Acid Anhydride Hydrolases↗