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Biomedical subjects

K Takakura

Publications and source records attributed to K Takakura.

At least 37 records · Page 2Linked to original sources
PubMed2001

The role of human chorionic gonadotropin on decidualization of endometrial stromal cells in vitro.

Although decidualization of endometrial stromal cells (ESC) is crucial for blastocyst implantation and maintenance of pregnancy, its complex mechanism still remains largely unknown. It has long been believed that hCG can directly induce in vitro decidualization of ESC via cAMP signaling. Recently, however, it has been reported that the LH/CG receptor is not present in human endometrium, and the direct effect of hCG on decidualization has become controversial. To reevaluate the exact effect of hCG on decidualization, human ESC were isolated and cultured with hCG and/or ovarian steroids. ESC treated with 17beta-estradiol plus progesterone (E(2)/P) transformed morphologically and produced significant PRL, whereas ESC treated with hCG alone showed no significant increase in PRL in culture medium and exhibited no morphological changes. Moreover, hCG did not promote E(2)/P-induced PRL production or intracellular cAMP accumulation, and protein kinase A inhibitor failed to block E(2)/P-induced PRL production. These results suggest that hCG does not directly affect in vitro decidualization of human ESC and that the process of E(2)/P-induced in vitro decidualization might consist of several pathways, including the intracellular cAMP signaling cascade.

Adult↗
PubMed2001

[A case report of Ebstein's anomaly treated with Hetzer's procedure].

A 27-year-old male who had been diagnosed with Ebstein's anomaly was admitted with uncontrollable congestive heart failure. The echocardiogram revealed severe tricuspid valve incompetence and the electrocardiogram showed atrial fibrillation. He underwent Hetzer's repair procedure for tricuspid valve incompetence and Minzioni's right atrial isolation technique to restore sinus rhythm. His congestive heart failure quickly disappeared and sinus rhythm was restored after operation. He was discharged 3 weeks postoperatively and remains well 22 months after his operation. Hetzer's technique for tricuspid valve repair in Ebstein's anomaly restructures the valve mechanism at the level of the true tricuspid anulus by using the most mobile leaflet for valve closure without plication of the atrialized chamber. We conclude that Hetzer's procedure is an effective operation for Ebstein's anomaly.

Adult↗
PubMed2001

Enhanced strand break induction of DNA by resonant metal-innershell photoabsorption.

We determined the number of single and double strand breaks (ssb and dsb) in a DNA-chloroterpyridine platinum complex induced by resonant photoabsorption in the L(III) innershell of a platinum atom. The number of ssb and dsb were measured in supercoiled plasmids (AG30) versus the chloroterpyridine platinum concentration, i.e., the ratio of intercalated molecules to the number of phosphate sites in DNA. A significant increase in the number of ssb and dsb was observed when the DNA contained intercalated molecules. This technique is an efficient way to induce ssb and dsb triggered by the atomic Auger effect.

Algorithms↗
PubMed2001

Spontaneous remission of cyclic neutropenia during pregnancy. A case report.

BACKGROUND: Cyclic neutropenia is characterized by regularly recurring episodes of neutropenia. It has been reported that pregnancy often has a mitigating effect on the symptoms. However, there have been no detailed studies on changes in the neutrophil count before, during and after pregnancy. CASE: A 24-year-old woman with cyclic neutropenia had a successful pregnancy, during which her symptoms improved spontaneously, with decreased severity. The disease recurred soon after pregnancy, and cyclic neutropenia was inherited by the child. CONCLUSION: Cyclic neutropenia may follow a favorable course during pregnancy, with decreased severity, but postpartum maternal and neonatal complications can occur.

Adult↗
PubMed2000

Determination of genes involved in the process of implantation: application of GeneChip to scan 6500 genes.

Using the high-density arrays of oligonucleotides (GeneChip) technology, the expression of uterine genes was examined before and after conceptus implantation in mice. Of the 6500 genes analyzed, levels of 399 gene expressions changed; 192 genes increased levels of expression while the remaining 207 genes declined. The findings suggest that both gene activation and deactivation (suppression) are required for successful implantation.

Animals↗
PubMed2000

Expression of cadherin and CSF dissemination in malignant astrocytic tumors.

Cadherins are Ca2+-dependent cell adhesion molecules that play an important role in tissue construction and morphogenesis in multicellular organisms. Because in recent years there have been reports of cadherin involvement in tumor metastasis, we conducted an immunostain for E-cadherin and N-cadherin monoclonal antibodies in paraffin-embedded surgical specimens of primary and recurrent lesions in 13 cases of glioblastoma and nine cases of anaplastic astrocytoma. No expression of E-cadherin was detected in the tumor cells. On the other hand, expression of N-cadherin was observed in malignant astrocytic tumor cells, but the N-cadherin positive rate tended to be less at the time of recurrence. Decreased expression of N-cadherin was detected at the time of recurrence in 11 of the 13 cases in the glioblastoma group. Cerebrospinal fluid (CSF ) dissemination and extracranial metastasis were observed in nine (81.8%) of these 11 patients. Therefore, we tried to analyze the clinical backgrounds and the N-cadherin positive rates by statistics. We concluded that decreased expression of N-cadherin at the time of recurrence correlates with dissemination in malignant astrocytic tumors.

Adult↗
PubMed2000

Mutation analysis of the growth differentiation factor-9 and -9B genes in patients with premature ovarian failure and polycystic ovary syndrome.

OBJECTIVES: To investigate whether growth differentiation factor (GDF)-9 or GDF-9B/bone morphogenetic protein (BMP)-15 mutation is present in Japanese women with premature ovarian failure (POF) and polycystic ovary syndrome (PCOS). DESIGN: Clinical and molecular studies. SETTING: Outpatient clinic in a university hospital. PATIENT(S): Fifteen women with POF, 38 women with PCOS, and 3 normal fertile controls. INTERVENTION(S): Extraction of DNA from blood samples for subsequent polymerase chain reaction (PCR). MAIN OUTCOME MEASURE(S): Amplified DNA was analyzed by denaturing gradient gel electrophoresis (DGGE) and/or by direct sequencing. RESULT(S): No missense mutation was found in any exons of the GDF-9 gene and the GDF-9B/BMP-15 gene in patients with POF and PCOS. CONCLUSION(S): The missense mutation in the GDF-9 gene or the GDF-9B/BMP-15 gene is uncommon in anovulatory Japanese women with POF and PCOS.

Adult↗
PubMed2000

Adsorption of lidocaine into a plastic infusion balloon.

An infusion balloon is a well established device used to continuously supply drugs for pain management. In this study, we determined the concentration of lidocaine that flowed out of a balloon because the balloon is made from plastics that adsorb local anesthetics.

Adsorption↗
PubMed2000

Thermological study of drilling bone tissue with a high-speed drill.

OBJECTIVE: To perform a detailed quantitative analysis of the effect of intermittent drilling and irrigation to lower the temperature during high-speed drilling. METHODS: We examined the thermal changes for 15 bone flaps while drilling a 7- x 7-mm area for 18 seconds and a specific point for 9 seconds, under the following conditions: continuous or intermittent drilling; with a fluted steel or a diamond ball cutter; without or with irrigation, with room temperature or cold (8 degrees C) Ringer solution. RESULTS: The maximum temperature during continuous drilling with a diamond cutter (or steel cutter) was 82.4 +/- 1.3 degrees C (55.2 +/- 1.0 degrees C) without irrigation, 42.5 +/- 1.2 degrees C (35.4 +/- 0.9 degrees C) with room temperature Ringer irrigation, and 22.5 +/- 1.4 degrees C (21.6 +/- 0.3 degrees C) with cold Ringer irrigation, whereas that during intermittent drilling was 66.1 +/- 1.2 degrees C (35.6 +/- 0.8 degrees C), 35.0 +/- 0.8 degrees C (25.4 +/- 0.7 degrees C), and 21.5 +/- 0.6 degrees C (21.8 +/- 0.4 degrees C), respectively. During continuous drilling of a specific point, the radius of the concentric isothermal line for 43 degrees C (thermal threshold for neurons) was 3.6 +/- 0.8 mm with a steel cutter, and it was 8.1 +/- 0.3 mm with a diamond cutter. The radius was 4.2 +/- 0.8 mm during intermittent drilling with a diamond cutter, and it was 4.0 +/- 0.1 mm during continuous drilling with room temperature Ringer irrigation. Intermittent drilling with cold Ringer irrigation kept the temperature, even at the center of the drilled area, below 20 degrees C. CONCLUSION: Intentional intermittent drilling with irrigation reduces temperature elevation and its expansion. These procedures are necessary for safe drilling, especially with a diamond burr. Although cold irrigation can minimize temperature elevation, its substantial effect on nerves or other structures needs to be elucidated.

Adult↗
PubMed2000

Clinical features of intracranial aneurysms in siblings.

OBJECTIVE: Among the family members of patients with aneurysmal subarachnoid hemorrhage (SAH), siblings have been documented to be at high risk of SAH and to have a high prevalence of unruptured aneurysms. We studied the distinctive features of aneurysms in siblings and attempted to determine the risk of rupture. METHODS: We analyzed detailed data on 159 patients with siblings who had ruptured and unruptured aneurysms in 77 families from throughout Japan. RESULTS: Seventy-three percent of the patients were female, and the mean age at the time of rupture was 55.6 years. In 39 families, two or more siblings had SAH. Eighty of 107 patients with ruptured aneurysms and 28 of 52 with unruptured aneurysms had a family history of SAH in siblings (P = 0.0082). Multiple and mirror-image aneurysms were found in 42 and 21 patients, respectively. Among 218 aneurysms, middle cerebral artery aneurysms were the most common type (43%). Anterior communicating artery aneurysms were underrepresented (15%). There were significantly more ruptured than unruptured anterior communicating artery aneurysms, compared with other aneurysms (P = 0.01). CONCLUSION: The clinical features of aneurysms in siblings in this population agreed well with those reported for familial intracranial aneurysms and SAH, except for the age at the time of rupture. It is suggested that the risk of rupture is greater when patients with unruptured aneurysms have siblings with aneurysmal SAH and/or anterior communicating artery aneurysms.

Aneurysm, Ruptured↗
PubMed2000

Strand break induction by photoabsorption in DNA-bound molecules.

Dried samples of a DNA-chloroterpyridine platinum complex were irradiated with monochromatic X rays tuned to the photoabsorption resonance of the L(III) inner shell of the platinum atom. The number of single- and double-strand breaks (SSBs and DSBs) triggered by the Auger effect in supercoiled DNA plasmids was measured by the production of circular nicked and linear forms. To probe the specific contribution of the L(III) inner-shell excitation of the platinum atom, photon wavelengths were tuned on the resonance energy (on peak) and below (off peak). The quantum yields of the resonance radiation were typically found to be 11 for the SSBs and 1 for the DSBs. The DSB-to-SSB ratio increased by 20% when switching from off-resonance to on-resonance irradiation.

DNA↗
PubMed2000

Gamma knife radiosurgery as a primary treatment for prolactinomas.

OBJECT: The purpose of this study was to estimate the efficacy of gamma knife radiosurgery (GKS) in controlling tumor growth and endocrinopathy associated with prolactinomas. METHODS: Between 1993 and 1997, 164 of 469 patients with pituitary adenomas treated by GKS harbored prolactinomas. The dose to the tumor margin ranged from 9 to 35 Gy (mean 31.2 Gy), and the visual pathways were exposed to a dose of less than 10 Gy. The mean tumor diameter was 13.4 mm. The mean follow-up time for 128 cases was 33.2 months (range 6-72 months). Tumor control was observed in all but two patients who underwent surgery 18 and 36 months, respectively, after GKS. Clinical cure was achieved in 67 cases. Clinical improvement was noted with a decrease in the hyperprolactinemia after GKS. Nonetheless, in 31 (29%) of 108 patients who were followed for more than 2 years no improvement in serum prolactin levels was demonstrated, although this could be normalized by bromocriptine administration after treatment. Nine infertile women became pregnant 2 to 13 months after GKS and all gave birth to normal children. There was no visual deterioration related to GKS. Five women experienced premature menopause. In these patients there was subtotal disappearance of the tumor and an empty sella developed. CONCLUSIONS: Gamma knife radiosurgery as a primary treatment for prolactinomas can be safe and effective both for controlling tumor growth and for normalization of prolactin hypersecretion. A higher margin dose (> or = 30 Gy) seemed to be associated with a better clinical outcome. Gamma knife radiosurgery may make prolactinomas more sensitive to the bromocriptine.

Humans↗
PubMed2000

Identification of the full-length KIAA0591 gene encoding a novel kinesin-related protein which is mapped to the neuroblastoma suppressor gene locus at 1p36.2.

The distal region of a short arm of chromosome 1p is frequently deleted in many human cancers including neuroblastoma (NBL), in which it has been narrowed down to the smallest region of overlap between D1S244 and D1S214 (approximately 7 cM). During the search for the candidate tumor suppressor genes mapped within the region, we found the KIAA0591 gene which encoded a new human kinesin-related protein with a homology to human axonal transporter of synaptic vesicles (ATSV). The kinesin is an intracellular motor protein and often associated with neuronal differentiation and survival. Here we identified a complete open reading frame of the KIAA0591 gene by screening a cDNA library derived from human substantia nigra. The KIAA0591 protein contains a possible pleckstrin homology (PH) domain at its carboxy-terminus. However, it did not possess a force-generating motor domain which is well conserved among kinesin superfamily members (KIFs). Northern blot analysis demonstrated that KIAA0591 mRNA was preferentially expressed in both adult and fetal brains, kidney, skeletal muscle and pancreas. KIAA0591 was expressed in favorable NBLs at higher levels than in unfavorable NBLs, although RT-PCR SSCP analysis showed no mutation within the coding region of the KIAA0591 gene, when 8 neuroblastoma tissues and 15 neuroblastoma-derived cell lines were examined. Thus, the full-length KIAA0591 gene may be a novel member of human KIF superfamily which lacks motor domain and might function as a tumor suppressor in an epigenetic but not a classic Knudson's manner.

Amino Acid Sequence↗