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Biomedical subjects

K Okamura

Publications and source records attributed to K Okamura.

At least 73 records · Page 4Linked to original sources
PubMed2001

[Three cases of advanced gastric cancer resected after successful treatment with the novel oral anticancer drug TS-1].

We operated on 3 patients with advanced gastric cancer after successful treatment with novel oral 5-fluorouracil derivatives (TS-1). In all 3 patients, gastrointestinal fiberscopy revealed a considerable reduction in the tumor after oral administration of TS-1 in our clinic. Case 1 underwent surgery after an interval of 1 day following oral administration of TS-1 for 18 days. Pathologically, no cancer cells were found in the resected stomach and a few cancer cells were found only in resected lymph nodes. In case 2, who underwent surgery after an interval of 7 days following oral administration of TS-1 for 14 days, a few cancer cells were found only in the submucosal layer of the stomach and no viable cancer cells remained in the metastasized lymph nodes. In case 3, who underwent surgery after an interval of 11 days following administration of TS-1 for 26 days, scattered cancer cells, mostly fibrotic, were found as far as the subserosal layer. The pathological effectiveness of chemotherapy was grade 2 or 3 in each case. Case 2 and 3 followed a satisfactory postoperative course; however, case 1 suddenly had endotoxinemia on the 7th postoperative day. Although the patient had temporary multiple organ failure, he recovered eventually. All 3 patients have been well without any signs of recurrence for more than a year after surgery.

Administration, Oral↗
PubMed2001

[Peripheral blood stem cell harvest for patients with germ cell tumors].

From January 1996 to December 1999, fifteen patients with germ cell tumors underwent peripheral blood stem cell harvest during 15 courses of bleomycin, etoposide, cisplatin (BEP), 4 courses of etoposide, ifosfamide, cisplatin (VIP) and 3 courses of high-dose etoposide mobilization at Nagoya University Hospital. We performed 29 aphereses during BEP, eight during VIP, and six during high-dose etoposide. Although we were able to harvest 4.4 x 10(6)/kg of median CD34 positive cells per apheresis during BEP, the number of stem cells (more than 4 x 10(6)/kg of CD34 positive cells), which are needed for tandem high-dose chemotherapy, could not be obtained during four courses of BEP. For three patients in whom white blood cell counts at nadir were 2,000/microL or more, however, the required number of CD34 positive cells were harvested. VIP provided only 1.7 x 10(6)/kg of median CD34 positive cells per apheresis, while, 7.3 x 10(6)/kg of CD34 positive cells were harvested during high-dose etoposide mobilization. The dose of G-CSF was a significant factor for the number of CD34 positive cells harvested during BEP (p = 0.02); however, there might be some relationship between the harvest and the number of the peripheral white blood cells on the day of apheresis (p = 0.08), the day to start G-CSF (p = 0.13), or the day to initiate apheresis (p = 0.27). Based on our experience, it is recommended that 5 micrograms/kg of G-CSF should be started from the 14th or 15th day of BEP until the last apheresis and that aphereses should be performed between the 19th and 21st day, especially at the days when the peripheral white blood cell count increases beyond 10,000/microL.

Adolescent↗
PubMed2001

[Differences between gynecological cancer patients taken care for at home and those taken care for at the hospital].

Thirty-five patients with end-stage gynecological cancer, twelve taken care for at home care and 23 taken care for at our hospital, were compared. The life span after recurrence was significantly (p < 0.05) longer in the group taken care for at home. The number of persons living with the patient was also significantly (p < 0.01) larger in the group taken care for at home. Moreover, the hospitalization in the end stage of the disease was significantly (p < 0.01) shorter in the group taken care for at home. The average hospitalization in the end was for 6.5 days. Four patients died at their home. Average period the 12 patients stayed at home was 52.7 days. Following matters are important in order to provide home care. 1. We must know the biological characteristics of the cancer. 2. It is important that it does not lose the timing to which shift to the home care, keeping good doctor-patient relationship. 3. Limit of the therapy against cancer and importance of treatment at home should be carefully and clearly explained to the patient.

Adult↗
PubMed2000

Dissociation of Kar2p/BiP from an ER sensory molecule, Ire1p, triggers the unfolded protein response in yeast.

The unfolded protein response (UPR) is a signal transduction pathway induced by a variety of endoplasmic reticulum (ER) stresses and functions to maintain homeostasis of the cellular membrane in eukaryotes. Various ER stresses result in the accumulation of unfolded proteins in the ER, which is sensed by the transmembrane protein kinase/ribonuclease Ire1p that transmits a signal from the ER to the nucleus in Saccharomyces cerevisiae. Here we report that the yeast ER chaperone Kar2p/BiP, a member of the HSP70 family found in the ER, directly regulates the UPR by the interaction with Ire1p. In the absence of ER stress, Kar2p binds the lumenal domain of Ire1p and keeps Ire1p in an inactive unphosphorylated state. Upon exposure of cells to ER stresses, Kar2p is released from Ire1p, resulting in activation of Ire1p and signal transduction to the nucleus. Subsequently, KAR2 mRNA is induced and Kar2p accumulates in the ER in a time-dependent manner, restoring the system to the basal state. This negative autoregulation is similar to the regulation of mammalian cytosolic chaperone Hsp70 via its interaction with heat shock factor 1.

Cloning, Molecular↗
PubMed2000

Radical cyclization in heterocycle synthesis. 11.(1) A novel synthesis of alpha,beta-disubstituted gamma-lactones via sulfanyl radical addition-cyclization using hydroximates as a tether

A combination of sulfanyl radical addition-cyclization of dienes connected with hydroximates and subsequent conversion of the resulting cyclic hydroximate to the lactones provides a novel method for the construction of alpha,beta-disubstituted gamma-lactones. Upon treatment with thiophenol in the presence of AIBN, dienes connected with hydroximates smoothly underwent sulfanyl radical addition-cyclization to give cyclic cis- and trans-hydroximates. Hydrolysis of cyclic hydroximates gave the desired cis- and trans-lactones in high yield. This method was successfully applied to the practical synthesis of (+/-)-oxo-parabenzlactone.

Journal Article↗
PubMed2000

Primitive synteny of vertebrate major histocompatibility complex class I and class II genes.

Major histocompatibility complex (MHC) class I and class II molecules bind to and display peptidic antigens acquired from pathogens that are recognized by lymphocytes coordinating and executing adaptive immune responses. The two classes of MHC proteins have nearly identical tertiary structures and were derived from a common ancestor that probably existed not long before the emergence of the cartilaginous fish. Class I and class II genes are genetically linked in tetrapods but are not syntenic in teleost fish, a phylogenetic taxon derived from the oldest vertebrate ancestor examined to date. Cartilaginous fish (sharks, skates, and rays) are in the oldest taxon of extant jawed vertebrates; we have carried out segregation analyses in two families of nurse sharks and one family of the banded houndshark that revealed a close linkage of class IIalpha and beta genes both with each other and with the classical class I (class Ia) gene. These results strongly suggest that the primordial duplication giving rise to classical class I and class II occurred in cis, and the close linkage between these two classes of genes has been maintained for at least 460 million years in representatives of most vertebrate taxa.

Amino Acid Sequence↗
PubMed2000

Adenovirus-mediated in utero gene transfer in mice and guinea pigs: tissue distribution of recombinant adenovirus determined by quantitative TaqMan-polymerase chain reaction assay.

Fetal somatic cell gene therapy could become an attractive solution for some congenital genetic diseases or the disorders which manifest themselves during the fetal period. We performed adenovirus-mediated gene transfer to mice and guinea pig fetuses in utero and evaluated the efficiency of gene transfer by histochemical analysis and a quantitative TaqMan-polymerase chain reaction (TaqMan-PCR) assay. We first injected a replication-deficient recombinant adenovirus containing the Escherichia coli LacZ gene driven by a CAG promoter (AxCALacZ) into pregnant mice through the amniotic space, placenta, or intraperitoneal space of the fetus. Histochemical analysis showed limited transgene expression in fetal tissues. We then administered AxCALacZ to guinea pig fetuses in the late stage of pregnancy through the umbilical vein. The highest beta-galactosidase expression was observed in liver followed by moderate expression in heart, spleen, and adrenal gland. The transgene expression was also present in kidney, intestine, and placenta to a lesser degree. No positively stained cells were observed in lung, muscle, or pancreas except in the vascular endothelium of these organs. Quantitative measurement of recombinant adenoviral DNA by the TaqMan-PCR assay showed that the vast majority of the injected viruses was present in liver. The current study indicated that adenovirus-mediated gene transfer into guinea pig fetus through the umbilical vein is feasible and results in efficient transgene expression in fetal tissues. The experimental procedures using pregnant guinea pigs might serve as a good experimental model for in utero gene transfer. Since our TaqMan-PCR assay detects the LacZ gene, one of the most widely used reporter genes, it may be generally applicable to adenovirus quantification in various gene transfer experiments.

Adenoviridae↗
PubMed2000

Triple carcinomas of the biliary tract associated with congenital choledochal dilatation and pancreaticobiliary maljunction.

We report a rare case of triple carcinomas of the biliary tract associated with congenital choledochal dilatation (CCD) and pancreaticobiliary maljunction (PBM). The patient was a 58-year-old Japanese man who complained of epigastralgia. Ultrasonography and computed tomography revealed an elevated lesion inside the markedly dilated extrahepatic bile duct, thickening of the gallbladder wall, and small polypoid lesions in the gallbladder. Magnetic resonance cholangiopancreatography and endoscopic retrograde cholangiopancreatography showed CCD and PBM. With a diagnosis of carcinoma of the bile duct and cholesterol polyps in the gallbladder, pylorus-preserving pancreaticoduodenectomy was performed. The resected specimen showed two elevated lesions in the dilated bile duct, cholesterol polyps, and an area of irregular mucosa in the gallbladder. Histopathological examination showed two carcinomas in the bile duct, an adenosquamous cell carcinoma, and a moderately differentiated tubular adenocarcinoma, and a well differentiated tubular adenocarcinoma of the gallbladder. Two years and 6 months after the operation, a solitary metastatic liver tumor was detected. Left hepatic lobectomy was performed. At present, 7 months after the second operation, the patient is doing well with no signs of recurrence. Multiple carcinomas in the biliary tract associated with CCD and PBM, including the details in the present patient, were reviewed.

Bile Duct Neoplasms↗
PubMed2000

X-chromosome inactivation in the human trophoblast of early pregnancy.

To investigate X-chromosome inactivation (XCI) in human trophoblasts during early pregnancy, trophoblast genomic DNA was extracted and analyzed for a Bst XI restriction endonuclease site polymorphism in the X-linked phosphoglycerate kinase gene, after digestion with methylation-sensitive Hpa II (control samples were digested instead with Afa I). Six villous trophoblast DNA samples were informative for the polymorphism (ie, heterozygous) and were derived from women homozygous for the polymorphism. These samples were then evaluated for XCI. In five of the six samples with Hpa II predigestion, the sizes of the two heterozygous band peaks differed; maternal X-chromosome (X(M))-derived alleles showed smaller peak sizes than paternal X-chromosome (X(P))-derived alleles, but the differences varied in degree. In samples obtained by microdissection from formalin-fixed, paraffin-embedded tissues (30 samples from different anchoring villi, and 38 samples from different branch villi), monoclonal band patterns of X(P)-derived alleles were observed more frequently than those of X(M)-derived alleles, but almost half of the samples showed polyclonal patterns. Our results suggest that a skewing of XCI exists in the human trophoblast; however, the degree of nonrandomness due to predominant X(P) inactivation appears to be restricted. It is probable that transcription of the X inactivation center (XIC) begins earlier in mice than in humans.

Clone Cells↗
PubMed2000

Quantitative analysis of estrogen receptor alpha and beta messenger ribonucleic acid levels in normal endometrium and ovarian endometriotic cysts using a real-time reverse transcription-polymerase chain reaction assay.

OBJECTIVE: To quantify messenger RNA (mRNA) levels of the two estrogen receptor isoforms, estrogen receptor-alpha (ER-alpha) and estrogen receptor-beta (ER-beta) in the eutopic endometrium and ovarian endometriotic cysts. DESIGN: Prospective study. SETTING: University hospital. PATIENT(S): Patients with endometriosis and patients with uterine leiomyoma or carcinoma in situ. INTERVENTION(S): Gonadotropin-releasing hormone agonist (GnRH-a)-treated (n = 12) or untreated (n = 24) endometriotic cysts were obtained from 36 patients during laparoscopic cystectomy. Eutopic endometrium tissues were obtained from 24 patients during or immediately after surgery. MAIN OUTCOME MEASURE(S): ER-alpha and ER-beta mRNA levels, using a real-time reverse transcription (RT)-polymerase chain reaction (PCR) assay, TaqMan RT-PCR. RESULT(S): Eutopic endometrium and ovarian endometriotic cysts showed predominantly higher levels of ER-alpha mRNA than ER-beta mRNA. Although ER-alpha and ER-beta mRNA levels in the eutopic endometrium were affected by a cyclic change in ovarian hormones, ovarian endometriotic cysts were less affected. Moreover, a long-term hypoestrogenic state induced by GnRH-a especially decreased ER-alpha mRNA levels in endometriotic cysts. Consequently, the relative ratios of ER-alpha to ER-beta mRNA levels in both GnRH-a-treated and untreated endometriotic cysts were significantly lower than those in the eutopic endometrium. CONCLUSION(S): The results suggest that the principal and regulatory effects of estrogens may be mediated mainly via ER-alpha rather than ER-beta in both the eutopic endometrium and endometriotic cysts.

Adult↗
PubMed2000

Growth pattern of twins of different chorionicity evaluated by sonographic biometry.

OBJECTIVE: To determine differences between growth patterns of monochorionic and dichorionic twins, and of concordant and discordant twins of both chorionicities. METHODS: We studied 70 cases of concordant twins (24 monochorionic, 46 dichorionic) and 45 cases of discordant twins (25 monochorionic, 20 dichorionic). In each case, growth was measured longitudinally by ultrasound biometry and the growth pattern was depicted. RESULTS: There were no differences in incremental growth between concordant monochorionic and dichorionic twins. The growth curve of concordant twins of both chorionicities was almost the same as that of a singleton until 34 weeks' gestation. However, in the discordant twins, the growth of the larger twin matched the growth curve of a singleton or concordant twin, but the growth of the smaller twin gradually decreased to the range of growth restriction. The growth curves for monochorionic discordant twins appeared to be representative of two groups, one of which had onset of discordancy before 24 weeks. CONCLUSION: It is clinically important to determine chorionicity early in twin pregnancies, to calculate the percentage of discordancy between the fetuses, and to examine longitudinal fetal growth curves in each chorionicity.

Biometry↗
PubMed2000

Pathologic examination of renal cell cancer by means of step-sectioning.

BACKGROUND: Because incidental detection of small renal cell cancers (RCC) has recently become increasingly common, nephron-sparing surgery for these cases has been more widely performed. Renal cell cancer was investigated by means of step-sectioning in order to determine which cases were suitable for nephron-sparing surgery and how it should be performed. METHODS: Pathology specimens obtained from 90 cases of radical nephrectomy were examined in 5 mm sections. We excluded large and invasive tumors from the present study. Particular attention was given to satellite tumor nodules (STN), pseudocapsules of the main tumor and vascular invasion. RESULTS: Satellite tumor nodules of cancer (STN-Ca) were found in seven of 90 cases (7.8%). Tumor size and grade was not correlated with the existence of STN-Ca. The distance between the main tumor and STN-Ca varied. with the pathology of the STN-Ca mostly resembling that of the main tumor. Pseudocapsules of the main tumor were incomplete in 53 cases (58.9%), but extracapsular invasion of more than 1 mm was not seen in tumors less than 50 mm in diameter. Through step-sectioning, a further six cases with microscopic vascular invasion were found. Vascular invasion within the main tumor was confirmed in 16 of 17 cases (94.1%) and within normal renal tissue in only one case. CONCLUSIONS: The incidence of existing STN-Ca was not high (7.8%) in the present study, we had not any characteristics in the cases with STN-Ca. As STN-Ca were rarely near the main tumor, we could not expect to resect STN-Ca with main tumor, resection to more than 1 mm outside the pseudocapsule was needed for complete resection of main tumor less than 50 mm in diameter. Normal renal tissue between the tumor and pelvis is a requirement for selecting appropriate cases in nephron-sparing surgery, but we could not remove the risk of leaving STN-Ca completely.

Adenoma↗
PubMed2000

Progesterone receptor isoforms A and B in human epithelial ovarian carcinoma: immunohistochemical and RT-PCR studies.

Human epithelial ovarian carcinoma is well-known as a sex steroid-dependent neoplasm, but the possible biological significance of progesterone receptor (PR) in this cancer remains controversial. Recently, two isoforms of human PR, PRA and PRB, have been characterized and different functional characteristics have been reported for these two isoforms. We therefore examined immunohistochemistry (107 cases) and reverse transcription-polymerase chain reaction (RT-PCR) (16 cases) for PRA, PRB, and oestrogen receptor-a (ER-a). Labeling indices (LI) for PRA and PRB were 2.4 and 43.6, respectively, and the difference was statistically significant. PRB LI, but not PRA LI, as well as performance status, stage, and residual tumour turned out to be independent prognostic factors following multivariate analysis. There was also a significant correlation between ER-a LI and PRB LI (r = 0.595, P < 0.0001), suggestive of a possible interaction between these two receptors. RT-PCR also detected the expression of PR isoform transcripts in the same pattern as was observed with immunohistochemistry. Results of these studies indicate that PRA and PRB both mediate distinct pathways of progesterone action in ovarian carcinoma. Moreover, it is important to examine PRB LI as a prognostic factor in the cases of human epithelial ovarian carcinoma.

Analysis of Variance↗
PubMed2000

Power spectral analysis of R-R interval variability before and during the sinusoidal heart rate pattern in fetal lambs.

OBJECTIVE: The appearance of the sinusoidal heart rate pattern found on fetal cardiotocograms has not been fully explained, either physiologically or clinically. In this study we performed power spectral analysis on the sinusoidal heart rate pattern obtained by administration of arginine vasopressin and atropine sulfate to investigate its frequency components in fetal lambs with long-term instrument implantation. STUDY DESIGN: Eleven tests were performed in 4 fetal lambs at 120 to 130 days' gestation. An artificial sinusoidal heart rate pattern was obtained by administration of atropine sulfate and arginine vasopressin in 9 tests. An autoregression model was used to compare the spectral patterns before and during the sinusoidal heart rate pattern. RESULTS: Marked decreases in low-frequency (0.025-0.125 cycles/beat) and high-frequency (0.2-0.5 cycles/beat) areas were observed in the presence of the sinusoidal heart rate pattern. However, there were no significant changes in the very-low-frequency area (0.01-0.025 cycles/beat), which corresponds to the frequency of the sinusoidal heart rate pattern. CONCLUSION: The sinusoidal heart rate pattern may represent a very low-frequency component inherent in fetal heart rate variability that appears when low- and high-frequency components are reduced as a result of strongly suppressed autonomic nervous activity.

Animals↗