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Biomedical subjects

S Yamada

Publications and source records attributed to S Yamada.

At least 523 records · Page 29Linked to original sources
PubMed1998

Peripheral blood mononuclear cells stimulate progesterone production by luteal cells derived from pregnant and non-pregnant women: possible involvement of interleukin-4 and interleukin-10 in corpus luteum function and differentiation.

Human luteal cells have been reported to express human leukocyte antigen-DR and lymphocyte functional antigen-3 on the cell surface, suggesting physiological interaction between luteal cells and T-lymphocytes through the menstrual cycle into early pregnancy. To elucidate the role of peripheral lymphocytes on corpus luteum differentiation, the effect of peripheral blood mononuclear cells (PBMC) on steroidogenesis by luteal cells was investigated. The production of Th-2 cytokines such as interleukin (IL)-4 and IL-10 by the co-cultured cells was also examined, and the effects of these cytokines on progesterone production by luteal cells were investigated. Corpora lutea were obtained from eight non-pregnant women in the luteal phase and five women in early pregnancy for luteal cell culture. PBMC were isolated from unrelated women in the follicular phase, secretory phase, and early pregnancy. After coculture with allogenic PBMC for 48 h, progesterone production was significantly enhanced by PBMC from the secretory phase and early pregnancy in the non-pregnant luteal cell culture. In the pregnant luteal cell culture, a significant increase in progesterone production was also observed by the co-culture with PBMC from women in early pregnancy, showing that PBMC have a luteotrophic effect. The stimulatory effects of PBMC were also observed in co-culture conditions which prevented direct cell-to-cell interaction with luteal cells, showing the minor influence of mixed lymphocyte reaction. By co-culture with PBMC, the production of IL-10, but not IL-4, was significantly augmented in luteal cell culture derived from non-pregnant women, whereas the production of both IL-4 and IL-10 was significantly enhanced in the luteal cell culture derived from pregnant women. Moreover, IL-4 and IL-10 promoted progesterone production by cultured luteal cells, especially in the luteal cell culture derived from corpora lutea of early pregnancy. These findings indicate that PBMC stimulate progesterone production by luteal cells and suggest the involvement of PBMC in corpus luteum function and differentiation probably via the Th-2-type lymphocytes.

Adult↗
PubMed1998

A monoclonal antibody, HCL-2, raised against human luteal cells reacts with apolipoprotein-B and detects the uptake of low density lipoprotein by luteinizing granulosa cells.

A monoclonal antibody, HCL-2, was raised by immunizing mice against human luteal cells. HCL-2 reacted with luteal cells and villous trophoblasts. The sodium dodecyl sulphate-polyacrylamide gel electrophoresis profile of immunopurified antigens from corpus luteum, chorionic villi, and placenta showed the same main protein band, the molecular mass of which is >200 kDa. The sequence of a portion of the N-terminal region of the antigenic protein purified from placenta was identical to that of apolipoprotein-B. The antigen purified from human serum and low density lipoprotein (LDL) using HCL-2 showed the same protein band as that from corpus luteum. Furthermore, the amino acid sequence (20 amino acids) of the protein purified from serum was also identical to that of apolipoprotein-B. Thus, we concluded that HCL-2 antigen is apolipoprotein-B. Human luteinizing granulosa cells isolated from the patients undergoing in-vitro fertilization treatment were cultured in the medium containing lipoprotein-deficient serum with or without supplementation of LDL. Using HCL-2, apolipoprotein-B was immunocytochemically detected on granulosa cells only in the presence of LDL. These findings showed that the uptake of LDL by granulosa cells was detected by immunocytochemical staining of apolipoprotein-B, indicating that HCL-2 is useful for analysing dynamic utilization of LDL by ovarian cells.

Adult↗
PubMed1998

Stage-specific uptake of apolipoprotein-B in ovarian follicles and corpora lutea of the menstrual cycle and early pregnancy.

A monoclonal antibody (mAb), HCL-2, was raised which reacts with apolipoprotein-B, and it was shown by immunohistology that HCL-2 can be used to analyse the uptake of apolipoprotein-B by steroid-producing cells in vivo. In this study we have investigated the dynamic utilization of low density lipoprotein (LDL) in human ovary by immunohistological localization of apolipoprotein-B and LDL receptors using HCL-2 and anti-LDL receptor mAb. In antral follicles, including those of <1 mm in diameter, both apolipoprotein-B and LDL receptors were localized to theca interna cells, but not granulosa cells. In pre-ovulatory follicles, the LDL receptor was expressed on all granulosa cells. Apolipoprotein-B was also detected in granulosa cells located at the basal layer, suggesting that they utilize LDL through the basal lamina before ovulation. In mid-luteal phase, large luteal cells seemed to stain more intensely for apolipoprotein-B than did small luteal cells, suggesting that large lutal cells are the main sites of LDL utilization. In regressing corpora lutea, the expression of LDL receptor was weak, and apolipoprotein-B was rarely detected. In corpora lutea of early pregnancy, LDL receptor and apolipoprotein-B were localized to both luteal cells. These findings show the precise dynamic changes in LDL uptake by human ovarian cells during their differentiation in vivo.

Adolescent↗
PubMed1998

Patterns of care study of radiation therapy for cervix cancer in Japan: the influence of the stratification of institution on the process.

BACKGROUND: To improve the quality of radiation oncology in Japan, Patterns of Care Study (PCS), a widely known quality assurance (QA) program in the USA, was introduced. The feasibility was tested by collecting nationwide data by extramural audit for cervix cancer. METHODS: From July 1996 through February 1997, PCS audits were performed for 29 institutions nationwide. On the basis of the facility survey by Tsunemoto, 13 institutions were classified as A1 (university hospital/cancer center), 10 as B1 (other institutions treating >120 patients/year) and six as B2 (other institutions treating <120 patients/year). Medical charts for the patients treated for cervix cancer between 1992 and 1994 were reviewed based on the data format of the US PCS. The total number of patients surveyed was 432. RESULTS: Simulation was used for >90% of the patients in both A1 and B1-2 institutions. However, in B1-2, planning for 5% of the patients was performed with only a clinical set-up (p = 0.0287). A daily fraction with a size of 200 cGy was given to >65% of patients in A1 and to <47% in B1-2. On the other hand, >50% of those in B1-2 were treated with daily fractions of 180 cGy and less compared with 25% in A1 institutions (p < 0.0001). Brachytherapy was utilized more frequently for patients in Stages II (p = 0.0365), III (p = 0.0015) and IV (p = 0.0483) in A1 than in B1-2. As for external beam equipment, linear accelerators with 10 MV or more were used for 83% of the patients in A1. However, in B1-2 institutions, machines with lower energy were used for 38% of the patients (p < 0.0001). The median number of full-time-equivalent (FTE) radiation oncologists was 2.7 in A1, 0.65 in B1 and 0.2 in B2. CONCLUSIONS: Institutional stratification, including equipment and personnel, was found to affect significantly the patterns of care for cervix cancer. Therefore, to improve the quality of radiation therapy nationwide, improvements in equipment and in supply of FTE personnel are extremely important. PCS was found to have great potential for a practical evaluation of how much improvement will be required in Japan.

Adult↗
PubMed1998

True calcium absorption in the intestine is enhanced by fructooligosaccharide feeding in rats.

Fructooligosaccharides (FOS) have been shown to stimulate apparent calcium absorption in the intestine. In this study, we examined the effect of FOS on true calcium absorption using the calcium balance in combination with the 45Ca kinetics method. Sixteen 45-d-old male Wistar rats were randomly divided into two groups, a control group (n = 8) and a FOS group (n = 8). The diet fed to the FOS group contained 5% FOS, at the expense of half of the sucrose in the control diet. After an adaptation period (3 d) and a free-access period (3 d) that were used to estimate the amount of food required for pair-feeding on the basis of calcium, all of the rats were pair-fed throughout the experiment from the age of 51 d. A constant amount of calcium was fed to the rats in each group (95 mg /d). At age 60 d, a 3-d metabolic study was started by the intravenous injection of 45Ca. Several variables were calculated on the bases of measurements of calcium intake, calcium in feces and serum, and 45Ca in feces, urine and serum. Both true and apparent calcium absorption in the intestine (Vad and Vna) and urinary calcium were significantly greater in rats that had been fed FOS. There were no differences between the groups in endogenous net calcium excretion into feces (Vf; Vad - Vna). The calcium balance was also enhanced by FOS. Calcium balance in the FOS group was significantly correlated with the absorbed calcium (r2 = 0.936, P < 0.01), as was that in the control group (r2 = 0.994, P < 0.01). These results suggest that the increased true calcium absorption and balance produced by FOS feeding might improve bone calcification.

Animals↗
PubMed1998

Membrane-bound carboxypeptidase-M is expressed on human ovarian follicles and corpora lutea of menstrual cycle and early pregnancy.

We have previously reported that membrane-bound aminopeptidases were expressed on human follicles and corpora lutea (CL) and we showed that these aminopeptidases are involved in follicular growth, probably by regulating extracellular peptide concentrations. In this study, the expression of membrane-bound carboxypeptidase-M (CP-M), which cleaves carboxyl-terminal amino acids from peptides extracellularly, on human follicles and CL was examined. In growing and pre-ovulatory follicles, CP-M was immunohistochemically detected with weak or moderate intensity on theca interna cells. Although CP-M was not detected on granulosa cells in growing and pre-ovulatory follicles, it was strongly detected on the cell surface of luteinizing granulosa cells isolated from patients undergoing in-vitro fertilization treatment, indicating that CP-M was rapidly expressed on granulosa cells during ovulation. In menstrual and pregnant CL, CP-M was clearly detected on luteal cells. In menstrual CL, the expression of CP-M mRNA was observed by reverse transcription-polymerase chain reaction (RT-PCR). Western blotting analysis revealed that the molecular mass of the CP-M extracted from mid-luteal CL was 62 kDa. These results indicate that CP-M is a cell surface differentiation-related molecule of human granulosa, theca, and luteal cells. The rapid expression on granulosa cells during ovulation strongly suggests the involvement of CP-M in the ovulation and CL formation processes.

Blotting, Western↗
PubMed1998

Characterization of heparinase from an oral bacterium Prevotella heparinolytica.

Heparinase was purified to homogeneity from the cell extract of an oral bacterium, Prevotella heparinolytica, by a combination of anion exchange chromatography, gel filtration chromatography, and hydroxyapatite chromatography. Properties of the purified P. heparinolytica heparinase (P. heparinase) were investigated. The enzyme exhibited a maximum activity in 50 mM Tris-HCl buffer, pH 7.5-8.0, containing 75 mM sodium acetate, 0.1 M NaCl, and 1 mM CaCl2. Optimum conditions for the maximum activity of P. heparinase were similar to those of the heparinase from Flavobacterium heparinum (F. heparinase). The two enzymes also yielded similar digestion profiles of various glycosaminoglycans and heparin tetrasaccharides, suggesting that they have a similar substrate specificity. Kinetic study of the P. heparinase reaction using porcine intestinal heparin as substrate gave a Km value of 3.8 x 10(-5) M and a Vmax value of 11.4 micromol/min x mg protein. The Michaelis constant of P. heparinase was slightly larger than but not significantly different from that of F. heparinase. The amino acid composition of P. heparinase was also similar to that of F. heparinase, but its N-terminal sequence of 20 amino acid residues was different and hitherto unreported. These results together indicate that these heparinases are different proteins with closely similar enzymatic properties. Since F. heparinum produces not only heparinase but also heparitinase II, which has a broad substrate specificity, F. heparinase may be contaminated with this enzyme. In contrast, P. heparinolytica does not produce heparitinase II, and P. heparinase should prove a useful tool for degrading heparin without the risk of contamination with heparitinase II.

Amino Acid Sequence↗
PubMed1998

EPR spectroscopic evidence for the mechanism-based inactivation of adenosylcobalamin-dependent diol dehydratase by coenzyme analogs.

EPR spectra were measured upon incubation of the complex of diol dehydratase with coenzyme analogs in the presence of 1,2-propanediol, a physiological substrate. When the analog in which the D-ribose moiety of the nucleotide loop was replaced by a trimethylene group was used as coenzyme, essentially the same EPR spectrum as that with adenosylcobalamin was obtained. The higher-field doublet and the lower-field broad signals derived from an organic radical and low-spin Co(II) of cob(II)alamin, respectively, were observed. With the imidazolyl counterpart, base-on cob(II)alamin-like species accumulated, but signals due to an organic radical quickly disappeared. When a coenzyme analog lacking the nucleotide moiety was incubated with apoenzyme in the presence of substrate, the EPR spectrum resembling cob(II)inamide was obtained, but no signals due to an organic radical were observed. From these results, it was concluded that the extinction of organic radical intermediates results in inactivation of the enzyme by these coenzyme analogs. Upon suicide inactivation with a [15N2]imidazolyl analog, the octet signals due to Co(II) showed superhyperfine splitting into doublets, indicating axial coordination of 5,6-dimethylbenzimidazole to the cobalamin bound to diol dehydratase.

Cobamides↗
PubMed1998

An endogenous target protease, SAM-P26, of Streptomyces protease inhibitor (SSI): primary structure, enzymatic characterization, and its interaction with SSI.

We have been focusing on the potent involvement of the molecular interaction between a protease and a protease inhibitor in the physiological or morphological regulation of Streptomyces cells producing them [Taguchi et al. (1995) J. Bacteriol. 177, 6638-6643; Suzuki et al. (1997) J. Bacteriol. 179, 430-438]. In this study, an extracellular protease, termed SAM-P26, was isolated as a target of endogenous protease inhibitor (SSI) from the culture medium of an SSI non-producing mutant strain derived from Streptomyces albogriseolus S-3253. Complete amino acid sequence determination revealed that SAM-P26 is identical to a protein encoded by the SAM-P20D gene, which was previously found to be located downstream of the gene for SAM-P20, another target protease of SSI. Based on the sequence homology, SAM-P26 was categorized as a member of the chymotrypsin family like SAM-P20. Sequence similarity between SAM-P26 and SAM-P20 was immunologically demonstrated by Western blot analysis using anti-SAM-P20 antiserum. The molecular mass (26 kDa) of SAM-P26 estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was much higher than that calculated from the amino acid sequence of SAM-P26 (18,376.8 Da) and that of the S-pyridylethylated form (18,808.4 Da) of SAM-P26 determined by Matrix-assisted Laser Desorption/Ionization-Time of Flight/Mass Spectrometry. Analytical gel-filtration analysis revealed that SAM-P26 exists as a monomer (18.8 kDa) in the native state. The results as to substrate specificity and inhibitor sensitivity indicated SAM-P26 exhibits chymotrypsin-like activity. For the proteolytic activity, the optimal pH was 10.5 and the optimal temperature was 60 degreesC. The complex formation of SAM-P26 with SSI was confirmed by native-PAGE analysis.

Amino Acid Sequence↗
PubMed1998

Saliva level of free 3-methoxy-4-hydroxyphenylglycol in psychiatric outpatients with anxiety.

As a measurement of the level of anxiety in psychiatric outpatients with anxiety, we determined the saliva level of free 3-methoxy-4-hydroxyphenyleglycol (MHPG) using gas chromatography- mass spectrometry and scored the levels of anxiety with the Hamilton Anxiety Scale (HAS) in patients, before and after drug treatment with alprazolam for 1 week. The saliva level of free-MHPG at first visit to hospital was significantly higher than that of control individuals and disease control individuals and was reduced by alprazolam treatment for 1 week. There was no correlation between MHPG level and the HAS score at the first hospital visit. The MHPG levels after treatment correlated with the HAS scores. The reduction of the anxiety level as scored by the HAS correlated with the reduction of MHPG level. These results indicate that the free saliva MHPG level may be a useful indicator for assessing not only the level of anxiety, but also the response to drug treatment for anxiety in these patients.

Adult↗
PubMed1998

Immunosuppressants decrease neutrophil chemoattractant and attenuate ischemia/reperfusion injury of the liver in rats.

BACKGROUND: Neutrophils may play an important role in the development of liver ischemia/reperfusion injury. We investigated the effects of the immunosuppressants azathioprine (AZA), cyclosporine A (CsA), tacrolimus (FK506), and rapamycin (RPM) on the expression of cytokine-induced neutrophil chemoattractant (CINC) after ischemia/reperfusion of the liver. METHODS: Liver ischemia was induced in male Wistar rats by occluding the portal vein with a microvascular clip for 30 minutes. Rats received two intramuscular injections of AZA (4 mg/kg), CsA (5 mg/kg), FK506 (0.5 mg/kg), or RPM (0.5 mg/kg) 3 and 24 hours before ischemia/reperfusion of the liver. RESULTS: Serum CINC concentrations in untreated animals increased, peaked 6 hours after reperfusion, and thereafter decreased gradually. Pretreatment with AZA, CsA, FK506, and RPM, however, inhibited the increase in serum CINC concentrations after reperfusion. CINC mRNA in liver tissue increased and peaked 3 hours after reperfusion, but was significantly lower in animals treated with AZA, CsA, FK506, and RPM. In vitro CINC production by Kupffer cells harvested from animals treated with AZA, CsA, FK506, or RPM 3 hours after reperfusion was also significantly lower than that observed in untreated animals. Both myeloperoxidase activity and the number of neutrophils accumulating in the liver 24 hours after reperfusion in animals treated with AZA, CsA, FK506, and RPM were significantly lower than in untreated animals. This correlated with lower serum aspartate transaminase, alanine transaminase, and lactate dehydrogenase levels in animals treated with AZA, CsA, FK506, and RPM 24 hours after reperfusion. CONCLUSION: The immunosuppressants AZA, CsA, FK506, and RPM reduce neutrophil accumulation and attenuate ischemia/reperfusion injury of the liver.

Animals↗
PubMed1998

Linkage mapping of the Bra, Brb and Brg genes for rat protein phosphatase 2A 55 kDa B-regulatory subunit isotypes.

We previously identified the rat Bra, Brb and Brg genes, which encode alpha, beta and gamma isotypes of the 55 kDa B-regulatory subunit of protein phosphatase 2A. Polymerase chain reaction-single strand conformation polymorphism analysis in the present study identified polymorphisms in Bra, Brb and Brg between the ACI and BUF, ZI and TM, and BN and WTC strains, respectively. Linkage analysis using mapping panels composed of F2 or back-crosses of these strains allowed Bra, Brb and Brg to be assigned to chromosomes 15, 18 and 14, respectively. Furthermore, it was revealed that Bra is located close to the Rb1 locus. Using polymorphism in Bra, loss of heterozygosity (LOH) was analyzed for rat mammary tumors induced in (SD x F344) F1 female rats by a food-borne carcinogen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, and a typical mammary carcinogen, 7,12-dimethylbenz[a]anthracene. No LOH was detected at the Bra locus.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1998

Time course of saliva and serum melatonin levels after ingestion of melatonin.

Salival and serum melatonin levels after melatonin ingestion were measured by gas chromatography-mass spectrometry. Ingestion of 3 mg melatonin caused a marked increase in serum melatonin (3561+/-1201 pg/mL) within 20 min, followed by a gradual decrease, but the level still remained higher than the basal level at 240 min after the ingestion. The saliva melatonin 60 min after the ingestion showed the highest level (1177+/-403 pg/mL) which was one-third of the plasma level. The saliva melatonin level was highly correlated with the serum level throughout the experimental period (r=0.82, P=0.0001). These data indicate that the measurement of saliva melatonin level may be a suitable indicator for the melatonin secretion into general circulation.

Adult↗
PubMed1998

Cartilaginous membranocystic lesions mimicking membranous lipodystrophy of bone.

Two cases are presented in which membranocystic lesions were observed in the cartilaginous tissue of surgical specimens. In both cases, the histological and ultrastructural features were reviewed, and S-100 protein distribution was examined immunohistochemically in one case. In both cases, the membranocystic lesions were observed to be adjacent to ballooned chondrocytes. In one case, several chondrocytes showed partially membranocystic lesions in their cytoplasm. The chondrocytes and nuclei in membranocystic lesions were stained positively for S-100 protein. It is suggested that the membranocystic lesions in the cartilaginous tissue were associated with the degeneration of the chondrocytes.

Adolescent↗
PubMed1998

Repair of septal and posterior tricuspid leaflets in Ebstein's anomaly.

BACKGROUND AND AIM: In Ebstein's anomaly, the septal and posterior tricuspid leaflets are plastered to the endocardium. We postulated that tricuspid valve function could be corrected by restoring mobility of these leaflets. (Feasibility of such repair was explored by anatomical and clinical studies.) METHODS: Ten heart specimens with Ebstein's anomaly were examined to investigate the size of the tricuspid leaflets. We operated on four patients with Ebstein's anomaly: the plastered septal and posterior leaflets were mobilized from the endocardium, the atrialized right ventricle was longitudinally plicated, and the basal attachment of the mobilized leaflets was sutured (reattached) to the valve annulus. RESULTS: In heart specimens, approximately 40% of the total surface of the tricuspid leaflets was comprised of the septal and posterior leaflets. Clinically, all patients operated on returned to normal functional status after surgery. The mean cardiothoracic ratio on chest X-rays decreased from 0.70 to 0.55 (after surgery). Echocardiographic tricuspid regurgitation, graded from 0 to 4, decreased from 3.5 to 1.0, and tricuspid annular diameter ratio to the normal value reduced from 1.88 to 0.66. Angiographic right ventricular ejection fraction increased from 0.36 to 0.50, and end-diastolic volume ratio to the normal value decreased from 3.65 to 1.19. CONCLUSIONS: Repair of the septal and posterior tricuspid leaflets was found to be feasible and effective as tricuspid valvuloplasty for Ebstein's anomaly.

Adolescent↗
PubMed1998

Formation of the dermal chromatophore unit (DCU) in the tree frog Hyla arborea.

In the tadpole of the tree frog Hyla arborea, the color of the dorsal skin was dark brown. Dermal melanophores, xanthophores, and iridophores were scattered randomly under the subepidermal collagen layer (SCL). After metamorphosis, the dorsal color of the animal changed to green and the animal acquired the ability of dramatic color change, demonstrating that the dermal chromatophore unit (DCU) was formed at metamorphosis. Fibroblasts invaded the SCL and divided it into two parts: the stratum spongiosum (SS) and the stratum compactum (SC). The activity of collagenase increased at metamorphosis. The fibroblasts appeared to dissolve the collagen matrix as they invaded the SCL. Then, three types of chromatophores migrated through the SCL and the DCU was formed in the SS. The mechanism how the three types of chromatophores were organized into a DCU is uncertain, but different migration rates of the three chromatophore types may be a factor that determines the position of the chromatophores in the DCU. Almost an equal number of each chromatophore type is necessary to form the DCUs. However, the number of dermal melanophores in the tadpoles was less than the number of xanthophores and iridophores. It was suggested that epidermal melanophores migrated to the dermis at metamorphosis and developed into dermal melanophores. This change may account for smaller number of dermal melanophores available to form the DCUs.

Animals↗
PubMed1998

[Bacteriological and virological studies on the cause of sporadic acute gastroenteritis in Tama, Tokyo (1991-1996)].

Between May 1991 and December 1996, bacteriological and virological investigations on the fecal samples from patient of infantile diarrhea (155 cases), or infectious gastroenteritis (1,409 cases) diagnosed with 9 medical institutions in Tama of Tokyo were carried out. Of 1,564 samples, 722 (46.2%) were enteropathogen positive cases, and mixed infection was also observed in about 15% of the positive cases. Among 13 different kinds of enteropathogens identified, the most prevalent one was pathogenic E. coli (20.7%), followed by Campylobacter spp. (10.0%), Rotavirus (8.8%), Salmonella spp. (3.9%), Adenovirus (1.9%), ECHO virus (0.9%), Vibrio parahaemolyticus (0.8%), Poliovirus (0.7%), Aeromonas spp. and Coxsackie B virus (both 0.6%). Furthermore, SRSV was confirmed in 82 out of 619 patients (13.2%) for 2 years (1995 and 1996). In addition, Shigella sonnei (3 cases), S. Paratyphi-A (1 case) and enterohemorrhagic E. coli O157: H7 (2 cases) were also detected. A higher detection ratio was recorded in February, August and November, reflecting respectively by month a highly frequency of Rotavirus, enteric bacteria causing food poisoning and SRSV. With reference to the isolates, the most of pathogenic E. coli belonged to enteropathogenic serotype E. coli (EPEC), and S. Enteritidis was most prevalent serotype.

Acute Disease↗