Biomedical subjects

K Okamura

Publications and source records attributed to K Okamura.

At least 37 records · Page 2Linked to original sources

PubMed2004

Comparison of the psychophysical properties of various intraoral film and digital systems by means of the perceptibility curve test.

OBJECTIVES: To compare psychophysical properties of two intraoral films and three digital systems using the perceptibility curve (PC) test. MATERIALS AND METHODS: A test object was used to determine the exposures and exposure differences between the total thickness of the test object and details consisting of holes of increasing depth. The PCs for the two intraoral films, UltraSpeed and EktaSpeed Plus, were constructed employing exposure and exposure differences from dose response functions. Integrals of the PCs were calculated to obtain the psychophysical properties of the two films. Psychophysical properties of the two films were compared with those of the three digital systems published previously (CDR, Dixel and Digora). RESULTS: The PC for the EktaSpeed Plus showed a slightly higher peak than that for the UltraSpeed. Available exposure ranges were comparable. The PC for the EktaSpeed Plus was shifted to the left of the exposure axis indicating its higher sensitivity as compared with UltraSpeed. All three digital systems had narrower but higher peaks compared with the films. The integrals for the digital systems were considerably larger than those for the two film types. CONCLUSIONS: All the three digital systems have superior psychophysical properties compared with the two tested films.

Absorptiometry, Photon↗

PubMed2003

Induction of cyclooxygenase-2 in human endometrial stromal cells by malignant endometrial epithelial cells: evidence for the involvement of extracellularly regulated kinases and CCAAT/enhancer binding proteins.

We previously reported that human malignant endometrial epithelial cell conditioned medium (MECM) up-regulated cyclooxygenase (COX)-2 mRNA and protein levels in human normal endometrial stromal cells (ESC). Here we showed that pretreatment with a selective inhibitor of the extracellularly regulated kinase (ERK)1/2 signaling pathway blocked the MECM-induced COX-2 expression in ESC. Transient transfection assays indicated critical roles of a cAMP response element (CRE,-59/-53 bp) and a nuclear factor for interleukin (IL)-6 expression (NF-IL6) site (-132/-124 bp) in the regulation of basal and MECM-induced activity of COX-2 gene promoter in ESC. Employing electrophoretic mobility shift assays, we demonstrated that increased functional binding of CCAAT/enhancer binding protein (C/EBP)alpha, C/EBPbeta and upstream stimulatory factor-2 to the CRE and C/EBPalpha and C/EBPbeta to the NF-IL6 site were, at least in part, responsible for MECM-induced COX-2 expression in ESC. Moreover, overexpression of C/EBPalpha and C/EBPbeta significantly induced COX-2 promoter activity in ESC. Collectively, these results suggest that the basal and MECM-induced transcription of the COX-2 gene in ESC is regulated through a combination of the CRE and the NF-IL6 site by functional interactions of C/EBPalpha and C/EBPbeta.

Base Sequence↗

PubMed2003

Efficacy of a polyurethane foam/spheroid artificial liver by using human hepatoblastoma cell line (Hep G2).

We invesigated the availability of human hepatoblastoma cell line (Hep G2), compared with human primary hepatocytes (HH) and porcine primary hepatocytes (PH), as a cell source for the hybrid artificial liver support system (HALSS) by using polyurethane foam (PUF). All three kinds of hepatocytes spontaneously formed spherical multicellular aggregates (spheroids) of 100-200 microm diameter in the pores of PUF within 3 days of culture. In a PUF stationary culture, Hep G2 spheroids recovered the ammonia removal activity that was lost in monolayer culture, although the removal for each unit cell number was about one tenth that of HH spheroids and about one eighth of PH spheroids. The synthesis activities of albumin and fibrinogen of each unit cell number of Hep G2 were also upregulated by PUF spheroid culture, and were about twice as high as in monolayer culture. The albumin secretion activity of Hep G2 spheroids was almost the same as that of PH spheroids. HH scarcely secreted these proteins in this experiment, probably because they were cultured in a serum-free medium. In the PUF module in a circulation culture, HH had high ammonia removal and low synthesis activities similar to stationary culture. Hep G2 proliferated to a high cell density, such as about 4.8 x 10(7) cells/cm3-module at 10 days of culture. Although Hep G2 spheroids had low ammonia removal activity in each cell, the removal rate in the PUF module was almost the same as for PH at 7 days of culture because of the high cell density culture by cell proliferation. The albumin secretion rate by Hep G2 in the PUF module also increased with cell proliferation and was about 10 times higher than the initial for the rate for PH at 7 days of culture. These results suggest that Hep G2 is a potential cell source PUF-HALSS.

Albumins↗

PubMed2002

Immunohistochemical expression of CA19-9 and CA125 in mucoepidermoid and adenoid cystic carcinomas of the salivary gland.

This study examined the immunohistochemical expression of carbohydrate antigens CA19-9 and CA125 and their relationship to various biological parameters in 27 mucoepidermoid carcinomas (MEC) and 18 adenoid cystic carcinomas (ACC) arising from salivary glands. The series showed higher immunopositivity for CA125 (67% for MEC; 33% for ACC) than for CA19-9 (59% for MEC; 11% for ACC). CA19-9 epitope was mainly expressed in cystic (MEC) and cribriform/tubular (ACC) components of carcinoma tissues. Solid components in MEC occasionally showed positive staining for CA19-9. CA125 was evenly expressed in both ACC and MEC tissues regardless of their different histological components. The positive expression of CA19-9 and CA125 in the carcinoma tissues did not influence the clinical course of patients with MEC and ACC. A significant relationship was only demonstrated between the immunohistochemical expression of CA125 and the low proliferative activity (LI) evaluated by Ki-67 immunohistochemistry. However, no significant relationship was found between LI and the patients' clinical course. These results suggest that the immunostaining for CA19-9 and CA125 provide no reliable data to predict the clinical course of patients with MEC and ACC of the salivary glands.

Adult↗

PubMed2002

Analysis of the human sperm centrosomal function and the oocyte activation ability in a case of globozoospermia, by ICSI into bovine oocytes.

BACKGROUND: Centrosomal function and oocyte activation ability of human sperm from a case of globozoospermia was assayed by heterologous ICSI into bovine oocytes. METHODS: Microtubules and chromatin configuration in bovine oocytes were examined by immunofluorescence after heterologous ICSI with human sperm from two fertile donors and from a globozoospermic man. RESULTS: The microtubule array from the sperm centrosome, the 'sperm aster' and the male pronucleus were observed in bovine oocytes, following ICSI with round-headed sperm from a globozoospermic man. The rate of sperm aster formation and the rate of male pronuclear formation in the bovine oocytes injected with fertile donor sperm were 57.9 and 92.5% respectively; the respective values for oocytes injected with round-headed sperm without artificial oocyte activation were 15.8 and 31.0%. Ethanol activation after ICSI improved male pronuclear formation (84.9%) but not sperm aster formation rate (32.3%) of the globozoospermic patient. CONCLUSIONS: These data indicated that sperm from this patient with globozoospermia have centrosomal dysfunction and low ability for oocyte activation compared with fertile donor sperm. The centrosomal dysfunction may be one of the reasons for infertility in this patient.

Animals↗

PubMed2002

Volume changes in human masticatory muscles between jaw closing and opening.

Most jaw muscles are complex, multipennate with multiple components. The morphologic heterogeneity of masticatory muscles reflects their functions. We hypothesized that the volume of masticatory muscles changes between jaw closing and opening, and that there is a difference in the volume change among the muscles. Magnetic resonance images of the entire head were obtained in ten normal young adult subjects before and after maximum jaw opening. The volume changes of the masseter, medial, and lateral pterygoid muscles were measured. Only slight changes were seen in the masseter and medial pterygoid muscles. The lateral pterygoid muscle, however, significantly decreased its volume during jaw opening. The results provide normative values of muscle volume in living subjects, and suggest that the volume changes differ among jaw muscles.

Adult↗

PubMed2001

Isochromosome consisting of terminal short arm and proximal long arm X in a girl with short stature.

A 16-year-old girl with short stature, short neck, shield chest, and cubitus valgus was studied. FISH analyses of her structurally altered X chromosome showed a der(X)- (wcpX+,TelXp/Yp++,SHOX++,STS++,KAL-, 37A12-,DXZ1+,XIST++,97L7++,300O13-,404F- 18-,417G15-,404F18-,140A-,TelXq/Yq-). These results, together with the high-resolution banding analysis, indicated her karyotype to be 46,X,der(X)(Xpter-->Xp22.3::Xq22.3--> cen-->Xq22.3::Xp22.3-->Xpter). The der(X) was an isochromosome, consisting of duplicated terminal short arms and duplicated proximal long arms. This in turn suggested that the chromosome was formed through pericentric inversion of an X chromosome, followed by isochromosome formation through sister chromatid exchange at Xp, close to the centromere. Replication R-banding analysis showed that the abnormal X chromosome was late replicating. Analysis of digestion patterns with a methylation-sensitive restriction endonuclease of the phosphoglycerate kinase 1 gene, located in Xq13.3, indicated that its inactivation patterns were completely skewed.

Adolescent↗

PubMed2001

Multiple intracranial recurrent tumors with hyperprolactinemia combined with a parasellar malignant fibrous histiocytoma long after transfrontal surgery and irradiation to a pituitary adenoma.

We herein describe a 40-year-old woman with hyperprolactinemia, an empty sella and two extrasellar intracranial recurrent tumors which were revealed 23 years after the first transfrontal craniotomy and 18 years after the second transfrontal surgery and irradiation to a provable prolactin-producing pituitary macroadenoma. One recurrent tumor was in the right orbital apex causing right oculomotor nerve palsy, and the other tumor was in the right apex partispetrosae and foramen jugulare. Although her serum prolactin level decreased after the administration of bromocriptine mesilate, and the size of the two tumors remained unchanged, a malignant fibrous histiocytoma, which might have been induced by the irradiation 18 years before, grew rapidly in the right suprasellar-prepontine cistern to the right pedunculus cerebralis, leading to a poor prognosis. This case confirmed the importance of the life-lasting follow-up of pituitary adenomas treated with surgery and/or irradiation therapy. Not only ectopic recurrence of the primary tumor but also post-irradiation tumors may become apparent long after the removal of the primary tumor.

Adult↗

PubMed2001

X chromosome inactivation patterns in 45,X/46,XX mosaics.

To investigate X chromosome inactivation (XCI) patterns in 45,X/46.XX mosaics, genomic DNA was extracted from peripheral blood samples of 15 female subjects who showed different proportions of 45,X cell clones. XCI patterns were analyzed using two assays. The first assay was the BstXI restriction endonuclease detection of an X-linked phosphoglycerate kinase (PGK) gene polymorphism following digestion of the DNA with methylation-sensitive HpaII, or with methylation-insensitive AfaI as a control. The second assay was the detection of a CAG triplet repeat polymorphism in the X-linked androgen receptor (AR) gene after sodium bisulfite treatment. Of the 15 subjects, 11 were informative due to heterozygosity for at least one of the polymorphisms (6 were heterozygous for the PGK polymorphism and 9 were heterozygous for the AR polymorphism). Four of the 11 informative subjects (36%) showed extremely skewed XCI for at least one of the polymorphisms, which was a much higher incidence than previously reported for normal females. Moreover, 3 of these 4 women had proportions of 45,X cell clones greater than 20%. Although our results may be due to several possible cytogenetic or molecular mechanisms, the most likely explanation is that cases of 45,X/46,XX that contain relatively high levels of 45,X cell clones probably arose due to structural aberrations of the X chromosome undetectable by conventional karyotyping.

Base Sequence↗

PubMed2001

A remnant tubal pregnancy after cloacal malformation repair.

OBJECTIVE: Report of a remnant tubal pregnancy after cloacal malformation repair. DESIGN: Case report. SETTING: A university hospital. PATIENT: A woman with cloacal malformation repair. INTERVENTION: Laparoscopic surgery. MAIN OUTCOME MEASURE: Remnant tubal pregnancy. RESULT: Laparoscopic right salpingectomy. CONCLUSION(S): In this patient, ectopic pregnancy was caused by contralateral sperm transmigration to the remnant right tube, which was not connected with the left uterus.

Adult↗

PubMed2001

Expression of the cyclin-dependent kinase inhibitor p27Kip1 in eutopic endometrium and peritoneal endometriosis.

OBJECTIVE: This study was undertaken to evaluate the immunohistochemical expression of the cell cycle inhibitor p27Kip1 and proliferation marker Ki67 in peritoneal endometriosis and eutopic endometrium. DESIGN: Prospective study. SETTING: University hospital. PATIENT(S): Thirty-one patients with peritoneal endometriosis. INTERVENTION(S): During laparoscopy, 25 samples of predominantly red peritoneal lesions and 27 samples of predominantly black peritoneal lesions were collected from 31 patients with endometriosis. Eutopic endometrium from 25 patients with endometriosis was collected by curettage during laparoscopy or just after surgery. MAIN OUTCOME MEASURE(S): The percentage of glandular and stromal cells exhibiting positive staining for p27Kip1 and Ki67 (labeling index, LI) was determined. RESULT(S): The LI of stromal cells in red peritoneal lesions for both p27Kip1 and Ki67 was similar to that of proliferative eutopic endometrium. Although the LI of glandular epithelial cells for Ki67 in red lesions was comparable to that of proliferative eutopic endometrium, the LI for p27Kip1 was significantly higher. Furthermore, we detected a significantly higher LI of glandular epithelial and stromal cells for p27Kip1 in black lesions compared with red lesions. CONCLUSION(S): Our results suggest that expression of the cyclin kinase inhibitor p27Kip1 is involved in the natural history and progression of peritoneal endometriosis.

Adult↗

PubMed2001

Expression of estrogen receptor alpha and beta in peritoneal and ovarian endometriosis.

OBJECTIVE: To quantify and compare messenger RNA (mRNA) levels of ER-alpha and ER-beta among ovarian endometriotic cysts and red and black peritoneal endometriotic lesions. DESIGN: Prospective study. SETTING: University hospital. PATIENT(S): Patients with or without endometriosis. INTERVENTION(S): Samples of peritoneal (n = 33) and ovarian endometriotic lesions (n = 37) were obtained during laparoscopic surgery. Normal eutopic endometrial tissues and macroscopically normal peritoneal tissues were obtained as controls during or just after surgery. MAIN OUTCOME MEASURE(S): Expression of mRNA for ER-alpha and ER-beta, using a real-time reverse transcription (RT)-PCR assay, TaqMan RT-PCR, and nonradioactive in situ hybridization (ISH) techniques. RESULT(S): Both eutopic endometrium and endometriotic tissues showed predominantly higher levels of ER-alpha than ER-beta mRNA. Relative ratio of ER-alpha to ER-beta (ER-alpha/ER-beta) mRNA in red peritoneal lesions was significantly higher than in black lesions and ovarian endometriotic cysts. There was no significant difference in ER-alpha/ER-beta between proliferative eutopic endometrium and red peritoneal lesions. These results were confirmed by ISH analysis, which also revealed that the two estrogen receptors were localized in both epithelial and stromal cells of endometriotic tissues. CONCLUSION(S): The predominant expression of ER-alpha in both glandular epithelial and stromal cells may be essential for the development and growth of peritoneal and ovarian endometriosis.

Adult↗

PubMed2001

Immunohistochemical analysis of the role of angiogenic status in the vasculature of peritoneal endometriosis.

OBJECTIVE: To investigate the angiogenic status of the vasculature in peritoneal endometriosis based on macroscopic appearance. DESIGN: Prospective study. SETTING: University hospital. PATIENT(S): Patients with peritoneal endometriosis. INTERVENTION(S): During laparoscopy, 25 samples of predominantly red peritoneal lesions and 27 samples of predominantly black peritoneal lesions were collected from a total of 31 patients with endometriosis. Eutopic endometrium from 25 patients with endometriosis was collected by curettage during laparoscopy or just after surgery. MAIN OUTCOME MEASURE(S): A proliferating endothelial cell index (PCI) was determined by calculating the percentage of microvessels that contained proliferating endothelial cells. A vessel maturation index (VMI) was determined by calculating the percentage of microvessels showing colocalization of CD34- and alpha-SMA-positive staining. RESULT(S): Peritoneal endometriotic tissues had extremely low or null PCI. The VMI of red peritoneal lesions was significantly lower than that of black ones. Vessel maturation index of red lesions was higher that that of proliferative eutopic endometrium and similar to that of secretory eutopic endometrium. CONCLUSION(S): Compared with the case of black peritoneal lesions, red lesions had a much higher fraction of immature vessels.

Actins↗

PubMed2001

Preferential X-chromosome inactivation in women with idiopathic recurrent pregnancy loss.

OBJECTIVE: To determine whether preferential X-chromosome inactivation (P-XCI) relates to idiopathic recurrent pregnancy loss. DESIGN: A retrospective study. SETTING: Infertility clinics and laboratory. PATIENT(S): Women with idiopathic recurrent pregnancy loss (group I), women who had given birth to children but with no history of spontaneous abortion (group II), and women without a history of pregnancy (group III). INTERVENTION(S): DNA samples from the heterozygotes for the (CAG)n polymorphism within the androgen receptor gene were modified with sodium bisulfite, PCR-amplified with primer pairs for methylated androgen receptor alleles (M-PCR) and unmethylated alleles (U-PCR), and subjected to electrophoresis. MAIN OUTCOME MEASURE(S): Band peak patterns and peak area sizes. RESULT(S): In group I, 7 (16.7%) of 42 heterozygotes exhibited P-XCI; four possessed single-peak patterns in the M-PCR and U-PCR products, and three had two-peak patterns in which the peak sizes differed considerably. In group II, 2 (5.6%) of 36 heterozygotes exhibited P-XCI as determined by the two-peak patterns. In group III, none of the 47 heterozygotes exhibited P-XCI. CONCLUSION(S): The incidence of P-XCI was statistically higher in group I than in the other groups. As P-XCI characterized by single-peak patterns was observed only in group I, such patterns, which may result from undiscovered cytogenetic or molecular abnormalities of the X-chromosome, likely correlate with pregnancy loss.

Abortion, Habitual↗

PubMed2001

A field evaluation of in situ biodegradation of trichloroethylene through methane injection.

A field study of biodegradation of trichloroethylene (TCE) through methane injection was conducted at the yard of a home in Japan. Methane was selected as the safest substrate for injection into groundwater. Methane, oxygen, nitrate, and phosphate were introduced into groundwater contaminated with 220 microg/L of TCE. After a week of biostimulation, methane concentrations gradually decreased below the detection limit. Methane oxidizing bacterial numbers increased from 10 to 10(4) cells/mL with methane consumptions. During methane injection. 10-20% of TCE removal was observed. The biotransformation yield was 3-13 mgTCE/gCH4 in this field test. After methane injections were stopped, TCE removal was not observed. These results indicated that bioremediation using methane was useful as a safe technology for a TCE-contaminated area near homes.

Biodegradation, Environmental↗

PubMed2001

Finger-assisted laparoscopy to remove a noncommunicating uterine horn.

A 21-year-old-woman had a double uterus with noncommunicating right uterine horn and communicating left uterine horn. The pelvic cavity showed evidence of endometriosis and adhesions from previous laparotomy. A finger was inserted under laparoscopic observation without gas leakage through an iris access port in the lower abdominal wall, which required only a small incision. An index finger was adequate to separate and manipulate inflamed tissue and to assess a connection of horns.

Abnormalities, Multiple↗

PubMed2001

Expression of p53 tumor suppressor gene in adenoid cystic and mucoepidermoid carcinomas of the salivary glands.

Seventeen adenoid cystic carcinomas (ACCs) and 27 mucoepidermoid carcinomas (MECs) occurring in the salivary glands were analyzed for p53 tumor suppressor gene alteration (exons 5-8) and protein expression. The cell proliferation activity was also examined by Ki-67 immunohistochemistry. The p53 alterations were detected in three samples (17.6%) of ACC and in four samples (14.8%) of MEC, and were only found in carcinomas arising in the minor salivary glands. The occurrence of the p53 gene alteration is less frequent in ACC and MEC than that in other kinds of tumors, and therefore does not seem to play a critical role in the course of the tumorigenesis in ACC and MEC. All ACC samples arising from the minor salivary glands exhibiting p53 gene alterations showed recurrence/metastasis, thus suggesting a poor outcome of these patients. All ACCs and three out of four MECs samples with p53 gene alterations showed the lowest degree of p53 immunostaining ratio, thus suggesting that no correlation exists between the p53 gene alterations and the p53 immunostaining in these salivary gland carcinomas. No significant relationship was demonstrated between the immunostaining ratio of either p53 or Ki-67 and the morphological growth pattern or patient clinical course in the ACC samples. The p53 immunopositivity in MEC correlated to the histological grade. The Ki-67 immunostaining ratio was also significantly related to the histological grade and the clinical course in MEC.

Adult↗

PubMed2001

Conventional and predicted perceptibility curves for contrast-enhanced direct digital intraoral radiographs.

OBJECTIVES: To construct Perceptibility Curves (PCs) for contrast-enhanced digital intraoral radiographs. METHODS: Radiographs of a test object having holes of increasing depths were exposed using three digital systems, the CDR (Schick Technologies, Long Island, NY, USA), the Dixel (J Morita MFG, Kyoto, Japan) and the Sens-A-Ray (Regam Medical Systems, Sundsvall, Sweden). The radiographs were contrast-enhanced and PCs constructed in the conventional way using 10 observers. Predicted PCs were calculated and compared with observer data. RESULTS: The PCs showed that contrast enhancement is effective for the perception of small contrast details, especially in the low exposure range. Predicted PCs demonstrated excellent agreement with observer data. CONCLUSIONS: Contrast enhancement should be advantageous in digital radiography. The effects of contrast enhancement on PCs may be predicted without previous knowledge of observer performance.

Algorithms↗