PubMed Health⌕ Search

Biomedical subjects

K Ohama

Publications and source records attributed to K Ohama.

At least 19 recordsLinked to original sources
PubMed1997

Fetal diagnosis of galactosialidosis (protective protein/cathepsin A deficiency).

The fetal diagnosis of galactosialidosis is performed by measuring carboxypeptidase (cathepsin A) activity in cultured villous cells and by immunofluorescence analysis with an antibody against an oligopeptide corresponding to the N-terminal domain of the human mature protective protein. Neither carboxypeptidase activity nor immunofluorescence was detected in cultured villous cells derived from an at-risk fetus or in cultured fibroblasts derived from the sister with galactosialidosis. Neuraminidase and beta-galactosidase activities were also confirmed to be deficient or low. A direct assay system for protective protein/cathepsin A is useful for the accurate prenatal diagnosis of galactosialidosis.

Antibodies↗
PubMed1997

Telomerase activity in ovarian tumors.

BACKGROUND: Shortening of telomeres occurs with each cell division and eventually results in cell death. The activity of telomerase, an enzyme that catalyzes telomere elongation, has been detected in germ cell lines and cancer cells, and has been detected in immortal cell lines but not in normal somatic cells. The relationship between telomerase expression and ovarian carcinogenesis was investigated. METHODS: Ovarian tissue was obtained from 41 women with ovarian tumors (10 benign, 6 borderline-malignant, and 25 malignant tumors) and 6 with uterine disease (2 with uterine myoma and 4 with uterine carcinoma). These specimens were analyzed for telomerase activity and telomere length by the telomeric repeat amplification protocol and Southern blot hybridization, respectively. RESULTS: Telomerase activity was detected in 23 of 25 malignant ovarian tumors (92%), in 1 of 6 borderline-malignant tumors (16.7%), and in 2 of 10 benign tumors (20%) (both of which were germ cell tumors). Weak telomerase activity was present in the cortex of normal ovaries from premenopausal women, and appeared to be attributable to follicles. Telomerase activity in malignant and poorly differentiated tumors tended to be higher than that in other tumors. Terminal restriction fragment length ranged between 8 and 13 kilobase pairs (kbp) for normal ovaries, and was <8 kbp in 1 of 6 malignant Stage I tumors (16.7%), 1 of 2 Stage II tumors (50%), and 9 of 17 Stage III tumors (52.9%). CONCLUSIONS: Telomerase activity may be a useful marker for the diagnosis of ovarian tumors.

Adult↗
PubMed1997

Stimulated rapid expression in vitro for early detection of in vivo T-cell receptor mutations induced by radiation exposure.

The T-cell receptor (TCR) mutation assay for in vivo somatic mutations is a sensitive indicator of exposure to ionizing radiation. However, this assay cannot be immediately applied after radiation exposure because expression of a mutant phenotype may require as long as several months. In the present study, we eliminate this time lag by stimulating lymphocytes with a mitogen that can accelerate the turnover of TCR protein expression in T-cells. When lymphocytes obtained from healthy donors were irradiated with various doses of X-rays and cultured with human interleukin-2 after phytohemagglutinin (PHA) pulse stimulation, the mutant frequency (MF) of CD4+ T-cells increased dose dependently during the first 7 days, then decreased rapidly due to the growth disadvantage of mutant cells. This suggests that PHA stimulation can shorten the expression time of a mutant phenotype to within a week after radiation exposure. The relationship between radiation dose and TCR MF on the seventh day was best fitted by a linear-quadratic dose-response model. We applied this improved TCR mutation assay to gynecological cancer patients who received 5 days of localized radiotherapy, totaling about 10 Gy. The in vivo TCR MF in the patients did not change within a week after radiotherapy, whereas the in vitro TCR MF of PHA-stimulated lymphocytes from the same patients significantly increased 7 days after initiating culture. The estimated mean radiation dose to the peripheral blood lymphocytes of the cancer patients was about 0.9 Gy, based on the in vitro linear-quadratic dose-response curve. This estimated dose was close to that described in a previous report on unstable-type chromosome aberrations from cervical cancer patients after receiving the same course of radiotherapy. On the basis of these findings, we propose that the improved TCR mutation assay is a useful biological dosimeter for recent radiation exposure.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1997

Alpha-fetoprotein (AFP) levels in normal children.

Alpha-fetoprotein (AFP) is an important tumor marker for yolk sac tumor and hepatoblastoma in childhood. We have been using the graph of the normal range of serum AFP made by Tsuchida et al, when we evaluate the serum AFP levels in early infancy. We measured the serum AFP levels by an immunoradiometric assay in 163 normal infants under 2 years of age, in order to make a more precise graph. Our normal range was a little wider than that of Tsuchida et al. According to our graph, false-positive cases would be fewer. Referring to the half-lives of serum AFP levels in normal infancy is also useful, when it is difficult to evaluate the AFP level.

Age Factors↗
PubMed1997

Assessment of sex chromosome ratio and aneuploidy rate in motile spermatozoa selected by three different methods.

Using three-colour fluorescence in-situ hybridization, sex chromosome ratios and frequencies of diploidy and disomy for chromosomes X, Y and 18 were compared in spermatozoa of good and poor motility after separation by swim-up, glass-wool and two-layer discontinuous Percoll methods. Semen samples were collected from seven normal males aged 26-31 years. A minimum of 6000 sperm nuclei per sample were evaluated for each chromosome for a total of 308,432 sperm nuclei. Hybridization efficiency was 99.8%. A slight change in the ratio of X- to Y-bearing spermatozoa was noted after Percoll separation (from 49.3:49.5 to 50.0:48.9; P = 0.036 and P = 0.046), but not after separation by the other two methods. We did not observe significant differences in the disomy rates for sex chromosomes or chromosome 18 or in the diploidy rate between spermatozoa with good and poor motility after separation by any of the three methods. Our data indicate that separation of motile spermatozoa does not alter the ratio of X- to Y-bearing spermatozoa to a degree that represents sex chromosome selection.

Adult↗
PubMed1997

A phenotypically normal liveborn male after prenatal diagnosis of trisomy 20 mosaicism.

We report on a case of prenatally diagnosed trisomy 20 mosaicism. Conventional cytogenetic analysis and fluorescence in situ hybridization (FISH) using a chromosome 20 specific probe were performed on the lymphocytes and extra-embryonic tissues after birth. All of them revealed normal karyotypes. The baby is developing normally at the age of 2 years.

Adult↗
PubMed1997

Expression of CD44 alternative splicing variants in primary and lymph node metastatic lesions of gynecological cancer.

CD44 is known as an adhesion molecule which is involved in lymphocyte activation and lymphocyte homing. In recent years, its role in the invasion and metastasis of malignant tumors has attracted the attention of investigators. In this study, the expression of CD44 variants was investigated in primary lesions and metastasis into the lymph node in 53 patients with gynecological cancer. The following patients with various types of gynecological carcinoma, established by operation and pre-treatment biopsy, were included in this study: 19 patients with cancer of the uterine cervix, 23 with cancer of the uterine endometrium, and 11 with ovarian cancer. Tissue samples were obtained from a primary lesion and a nodal metastasis of each patient, and immunohistochemical staining was performed by the ABC method through the use of monoclonal antibodies against CD44v1-10. Specimens proving CD44v1-10 positive were then submitted to immunohistochemical staining through the use of monoclonal antibodies against CD44v6 and CD44v9. Expression of CD44v was judged positive when DAB revealed color development, irrespective of the degree of staining intensity. CD44v were all expressed in the cancer cell membrane. In normal endometrium, expression of CD44v1-10 and v9 was observed in the endometrial gland cell membrane. In normal ovarian tissues, CD44v6 and v9 were not detected. The expression of CD44v6 in patients with endometrial cancer was noted in 13 (72.2%) of 18 patients with vascular invasion and in one (20.0%) of 5 patients without it, indicating a significant relation to vascular invasion. It was also remarkably higher in those for whom the invasion exceeded 1/2 of the myometrium than in those for whom the invasion did not exceed 1/2 of the myometrium, and was higher too in advanced stages and in node-positive patients. In one patient, CD44v6 was detected not in the primary lesion but in the nodal metastasis. The expression of CD44v6 in patients with ovarian cancer occurred more frequently in node-positive patients. Our study results suggest that the expression of CD44v6 in endometrial adenocarcinoma cells is involved in the progression of the carcinoma, nodal metastasis, myometrial invasion, and vascular invasion, and that in ovarian cancer, the expression of CD44v6 is involved in nodal metastasis.

Alternative Splicing↗
PubMed1997

Interleukin-1 as an autocrine stimulator in the growth of human ovarian cancer cells.

The role of interleukin-1 (IL-1), a multifunctional cytokine which mediates important immune responses, was investigated in the growth of ovarian cancer cell lines in vitro. The messenger RNA for IL-1 alpha and IL-1 beta was expressed in six and four ovarian cancer cell lines, respectively out of eight. Measurement of IL-1 in the eight cell lines by enzyme-linked immunosorbent assay revealed that two lines, MCAS and TYK-nu, secreted a high amount of IL-1 alpha, but that none secreted IL-1 beta after 72 hours of incubation. The growth of these cells was significantly stimulated by the addition of recombinant IL-1 alpha (rIL-1 alpha) in a concentration-dependent manner in a 96 hour culture. The maximum response was obtained with 10 ng/ml of IL-1 alpha by counting the viable cell number using trypan blue. [3H]-thymidine incorporation by these cells was also stimulated by a 72 hour incubation with rIL-1 alpha. The spontaneous growth of these cells was inhibited by the addition of anti-IL-1 alpha antibody, anti-IL-1 receptor antibody or IL-1 receptor antagonist. These cells expressed two classes of IL-1 binding receptors on their surface as detected by [125I]-labeled rIL-1 alpha. These results indicate that IL-1 alpha is an autocrine growth stimulator for some ovarian cancer cells and suggest that IL-1 alpha plays an important role in the progression of this disease.

Antibodies, Monoclonal↗
PubMed1997

Prevalence of uterine myoma detected by ultrasound examination in the atomic bomb survivors.

Benign tumors of several organs have been demonstrated to occur as late effects of atomic bomb exposure, and a recent addition to the list of affected organs is the uterus. The increased incidence of uterine myoma noted in Radiation Effects Research Foundation (RERF) Adult Health Study Report 7 (Wong et al., Radiat, Res. 135, 418-430, 1993), however, was based on self-reported information, optional gynecological examination and patient-requested ultrasound examination. Thus the possibility of dose-related bias in case detection was a serious concern. Therefore, the relationship between the prevalence of uterine myoma and dose to the uterus was examined after excluding as much bias as possible by asking all women who had undergone biennial examinations from December 1991 through December 1993 to undergo ultrasound examinations. Among 2506 female participants in Hiroshima, the uterus was visualized by ultrasound examination in 1190, and 238 were found to have uterine nodules. Multiple logistic analysis using Dosimetry System 1986 uterine doses revealed a significant dose response for the prevalence of uterine nodules. The odds ratio at 1 Gy was 1.61 (95% confidence interval: 1.12-2.31). It is unlikely that the observed relationship after adjusting for bladder filling, volume of the uterus, age and menopause status was the result of dose-related bias. These results support previous findings at RERF and provide further evidence that radiation exposure is one of the factors associated with uterine myoma.

Adult↗
PubMed1996

Detection of chromosomal abnormalities in uterine leiomyoma using conventional cytogenetic method and interphase fluorescence in situ hybridization.

Seventy-nine uterine leiomyomas were examined using a conventional cytogenetic method and fluorescence in situ hybridization (FISH) for detection of chromosomal abnormalities of chromosome 12. Nine (17.6%) of 51 tumor samples examined showed chromosomal abnormalities by conventional cytogenetic analysis. Rearrangements of chromosome 12 were detected in two tumors. Other tumors showed abnormalities affecting chromosomes 1, 4, 6, 7, 10, 13, 14, and 22. For FISH, the whole-chromosome painting probe and the D12Z3 probe specific for the centromeric region were used to detect structural and numerical abnormalities of chromosome 12. Of forty-one tumor samples, six showed structural aberrations and four showed numerical aberrations of chromosome 12 by FISH analysis. Of the tumors with structural aberrations identified by FISH, two had normal karyotypes, two showed structural rearrangements of chromosome 12 cytogenetically, and two could not be analyzed because of an insufficient number of metaphases. There were no correlations between the cytogenetic data and clinical parameters. The results indicate that chromosomal abnormalities are important in the biology of at least some types of uterine leiomyomas, and that FISH is a useful complement to conventional cytogenetic analysis in the study of solid tumors.

Adult↗
PubMed1996

Detection of aneuploidy in human spermatozoa using fluorescence in situ hybridization (FISH).

Fluorescence in situ hybridization (FISH) with chromosome specific alpha-satellite DNA probes was used to estimate the rates of aneuploidy of chromosomes 1, 17, 18, X and Y in human ejaculated sperm. Sperm samples were collected from six donors, and biotinylated DNA probes, D1Z5, D17Z1, D18Z1, DXZ1 and DYZ3 were hybridized to interphase sperm which had been pretreated with dithiothreitol to expand their nuclei. A minimum of 3,000 sperm per donor were analyzed. The hybridization efficiency was 99.68% for all the five probes. The frequencies of aneuploidy for chromosomes 1, 17 and 18 were 0.65%, 0.66%, and 0.61%, respectively. For XX- and YY-sperm the frequencies were 0.28% and 0.27%, respectively. To estimate the diploidy and disomy rates, a mixture of D17Z1 and D18Z1 were used as probes, and the frequency of diploid sperm was calculated to be 0.27%. After subtraction of the diploidy rate, the disomy rates for chromosomes 1, 17, and 18 were estimated to be 0.38%, 0.39% and 0.33%, respectively. The proportion of X- and Y-bearing sperm were 49.90% and 49.66%, consistent with an expected 1:1 ratio.

Aneuploidy↗
PubMed1996

Detection of chromosomal abnormalities of chromosome 12 in uterine leiomyoma using fluorescence in situ hybridization.

Fifty uterine leiomyomas were examined using conventional cytogenetic method and fluorescence in situ hybridization (FISH) for detection of chromosomal abnormalities of chromosome 12. Of the 50 tumors, nine were examined using FISH on the non-cultured samples. Two (4.0%) of 50 tumor samples examined showed chromosomal abnormalities of chromosome 12 by the conventional cytogenetic analysis. For FISH, the whole-chromosome painting probe and D12Z3 probe specific for the centromeric region were used. Of the 50 cultured samples, 10 showed structural aberrations and four showed numerical aberrations of chromosome 12 by FISH analysis. Of the nine non-cultured samples, four showed structural abnormalities of chromosome 12, all of which also showed structural abnormalities of chromosome 12 on the cultured samples. These results indicate that chromosomal abnormalities of chromosome 12 are important in the biology of at least some types of uterine leiomyoma, and that FISH is a useful complement to the conventional cytogenetic analysis in the study of solid tumors.

Chromosome Aberrations↗
PubMed1996

Relationship between the mandibular and lumbar vertebral bone mineral density at different postmenopausal stages.

OBJECTIVE: To analyse the relationship between mandibular and general skeletal mineral status at two different postmenopausal stages. METHODS: Using dual energy quantitative computed tomography, the mandibular and 3rd lumbar (L3) vertebral bone mineral density (BMD) were evaluated in 21 women within five years after the menopause (recent postmenopause) and 23 women more than five years after (long-term postmenopause). RESULTS: There were significant correlations between the mandibular cortical and L3 vertebral BMD (p < 0.01) in the recent postmenopausal women and between the mandibular BMD and the trabecular BMD of L3 vertebrae (p < 0.05) in the long-term postmenopausal women. CONCLUSION: These results suggest that the general mineral status more markedly affects the mandibular cortex in the recent postmenopausal stage and both cortical and trabecular bone in the long-term postmenopausal stage.

Adult↗
PubMed1996

[Classification of US findings of ovarian masses in children].

The ultrasonographic findings of 25 lesions in 23 patients with surgically proven ovarian masses were reviewed. There were 10 cystic teratomas, two simple cysts, two follicular cysts, two mucinous cystadenomas, two NHL, one corpus luteum cyst, one hydrosalpinx, one serous cystadenoma, one yolk sac carcinoma, one dysgerminoma, one embryonal carcinoma, and one mixed form (yolk sac carcinoma, choriocarcinoma). All patients were less than 15 years old. We classified all cases into four patterns: cystic, cystic with mural nodule, mixed, and solid. Eight lesions of the cystic pattern included two simple cysts, two follicular, cysts and one corpus luteum cyst. The other lesions were benign, too. Nine lesions with the cystic with mural nodule pattern consisted of eight cystic teratomas and one mucinous cystadenoma. All lesions were benign. The mixed pattern was seen in four lesions, half of which were malignant, i. e., one embryonal carcinoma and one yolk sac carcinoma. Four lesions with the solid pattern were all malignant masses: one dysgerminoma, two NHL and one mixed form. In this classification, the cystic and cystic with mural nodule patterns are benign, while mixed and solid patterns are highly suggestive of malignancy.

Adolescent↗
PubMed1995

Somatic-cell mutations as a possible predictor of cancer risk.

The somatic-mutation theory of carcinogenesis has received strong scientific support from results of recent studies on tumor-suppressor genes. We anticipated that people among the high risk for cancer group, either through exposure to various ionizing radiations or by virtue of unique genotypes, would also manifest increased frequencies of somatic mutation. This report presents the results of two somatic-mutation assays--at the erythrocyte glycophorin A (GPA) and lymphocyte T-cell receptor (TCR) genes--in various groups at high risk for cancer development, including atomic-bomb survivors, patients with various cancers, patients administered Thorotrast, and patients with genetic disorders that make them cancer prone. Although neither the GPA-mutation nor the TCR-mutation assay detects gene mutations directly related to carcinogenesis, increased mutation frequencies were detected by both assays in many individuals among the high-risk groups and among cancer patients. We have continued to follow up those individuals who show values of about three times higher than those of the control group. Thus, these assays may prove useful for identifying high-risk cancer groups and for estimating the effects of mutagens. Such information would constitute a valuable data base for epidemiological studies.

Adult↗
PubMed1995

Human spermatozoa attach to trypsin-treated hamster zonae pellucidae but do not undergo acrosome reactions.

The acrosome reaction by spermatozoa is an indispensable prerequisite for fertilization, and zonae pellucidae of human oocytes induce this reaction in the human spermatozoa attached to them. Human spermatozoa can attach to the zona pellucida of hamster oocytes when the oocytes have been treated with trypsin. We examined whether or not trypsin-treated hamster zona pellucida induces the acrosome reaction of human spermatozoa. Ten semen samples from 7 donors of proven fertility were examined in the present study. Highly motile spermatozoa were obtained by a swim-up method, and pre-incubated for 1 or 6 hours in modified Biggers, Whitten and Whittingham's (mBWW) medium supplemented with human serum albumin. The spermatozoa were then co-incubated for 1 hour with trypsin-treated hamster oocytes to allow sperm attachment to the zona. The spermatozoa on the zona were incubated for 3 additional hours in the mBWW medium. The percentage of acrosome reacted spermatozoa (%AR) was determined before and after the 3-hours of incubation. The %AR in the sperm suspension was also determined. There was no significant difference in the %AR between the spermatozoa attached to the zona pellucida and those in suspension during the incubation for 3 hours. These results indicate that the trypsin-treated hamster zona pellucida does not induce the acrosome reaction of human spermatozoa.

Acrosome↗