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K Takakura

Publications and source records attributed to K Takakura.

At least 145 records · Page 8Linked to original sources
PubMed1995

Developmental potential of frozen-thawed human blastocysts.

PURPOSE: To examine the possibility of freezing human embryos at late cleaved stages (morula or blastocyst stage), we cryopreserved human embryos 5 days (day 5) or 6 days (day 6) after insemination and investigated their developmental potential after thawing. MATERIALS AND METHODS: One hundred nineteen morphologically good-quality human embryos from 43 women undergoing in vitro fertilization treatment between 1991 and 1992 were frozen using dimethylsulfoxide as a cryoprotectant. The embryos were cryopreserved for 5 to 30 months. After thawing they were then cultured in vitro for 24 hr to investigate their developmental potential. Survival rates and developmental rates were morphologically assessed after 24 hr of in vitro culture. RESULTS: Developmental rates were significantly (P < 0.01 or P < 0.05) lower than survival rates at every developmental stage. There was no difference in total survival rates between embryos frozen 5 days after insemination (78.2%; 54/69) and embryos frozen 6 days after insemination (70.0%; 35/54). However, the developmental rates after 24 hr of culture was significantly (P < 0.05) lower for embryos frozen 6 days after insemination (6.0%; 3/50) than for embryos frozen 5 days after insemination (18.8%; 13/69). Only two embryos developed into fetuses after transfer into the uterus (1.7%; 2/119). CONCLUSIONS: From the results, the developmental potential of frozen-thawed human blastocysts was found to be significantly reduced, even though the blastocysts were of morphologically good quality. Longer in vitro exposure of embryos appears to reduce their developmental potential.

Blastocyst↗
PubMed1995

Differential microcirculation dynamics during deliberate hypotension induced by nicardipine, PGE1 and trimethaphan in rat mesentery.

The purpose of this study was to determine the arteriolar changes that occur in the microcirculation during deliberate hypotension and general anaesthesia and whether the changes depended on the drugs used to induce vasodilatation or on the degree of systemic blood pressure decrease. Changes in the vessel diameter and the velocity of red blood cells in the mesenteric arterioles of pentobarbitone-anaesthetized rats were observed using continuous biomicroscopy. Observations were made during deliberate moderate (BP 70 mmHg) or deep (BP 50 mmHg) hypotension by titration with nicardipine, prostaglandin E1 (PGE1) or trimethaphan. Then, the responses of arterioles to locally applied noradrenaline (1 microgram) were assessed. During moderate hypotension PGE1 decreased the arteriole diameter slightly (16.7 +/- 1.6 to 14.7 +/- 1.3 microns, P < 0.05), reduced the velocity of red blood cells considerably (1.98 +/- 0.2 to 1.03 +/- 0.4 mm.sec-1, P < 0.05) and increased the contractile response of arterioles to locally-applied noradrenaline. Nicardipine and trimethaphan had no effect on the microcirculation. During deep hypotension, all drugs decreased the diameter of the arterioles slightly but reduced the velocity of red blood cells considerably (P < 0.05). We conclude that the major change in the mesenteric arterioles during deliberate hypotension during general anaesthesia is a decrease in red blood cell velocity that is dependent on the drug used and the degree of blood pressure decrease.

Alprostadil↗
PubMed1995

Management of intracranial hemorrhage associated with anticoagulant therapy.

BACKGROUND: Intracranial hemorrhage may be a particularly devastating complication of anticoagulant therapy. Very few accounts have reported data on the duration of anticoagulant discontinuation following intracranial hemorrhage or the intensity of anticoagulation during treatment for it, although we must adequately manage such a complication. METHODS: We analyzed the management of warfarin-related intracranial hemorrhages in 27 patients with cardiac diseases. We evaluated the degree of anticoagulation using the thrombotest. Anticoagulants were stopped as soon as the diagnosis of intracranial hemorrhage was established by computed tomographic scan. RESULTS: Mechanical valve prosthesis patients, who required intensive long-term anticoagulant therapy, constituted the majority of our series (74.1%). Intraoperative hemostasis was brought under control despite low thrombotest values (13%-68%) at the time of surgery except for the acute subdural hematoma (SDH) patients with cerebral contusion. Early resumption of anticoagulant therapy (within 3 days) did not cause intracranial rebleeding in any operative patient. All the chronic SDH patients and some of the subcortical hematoma patients had a good outcome. All three patients with acute SDH and contusion, however, had a fatal outcome because of intracranial rebleeding within a short period of time or ineffective intraoperative hemostasis. CONCLUSIONS: The patients with anticoagulant-related intracranial hemorrhage may undergo surgery with thrombotest values approximately between 20% and 60%, and anticoagulants can be resumed after an interval of 3 days. Aggressive surgery should particularly be performed in patients with anticoagulation-related chronic SDH or subcortical hemorrhage, as in the cases of anticoagulant-unrelated intracranial hemorrhage.

Adolescent↗
PubMed1995

A mouse monoclonal antibody, S2n8, detects a 140 kDa protein on the surface of human endometrial stromal cells and decidual cells.

We developed a mouse monoclonal antibody, S2n8, by immunizing mice i.p. with human decidual cells collected in the first trimester of pregnancy. By indirect immunofluorescence staining of frozen sections, S2n8 was found to react with decidual cells and endometrial stromal cells throughout the menstrual cycle, but not with endometrial glandular cells or with the endometrial surface epithelium. Judging from the fluorescence intensity, the antigen expression on stromal cells was weak in the proliferative phase, and became stronger in the secretory phase. Decidual cells in the first trimester of pregnancy and decidual cells at term showed strong expression of this antigen. Indirect immunofluorescence staining of enzymatically dispersed decidual tissue revealed that the S2n8 antigen was expressed on the decidual cell surface. Flow cytometric analysis of 12 freshly prepared stromal cell-enriched cell suspensions showed that 74.8-94.2% (mean +/- SD 86.1 +/- 6.6%) of the cells carried the antigen. The expression of S2n8 antigen on cultured stromal cells was enhanced by the addition of oestradiol and/or progesterone. The antigenic molecule was purified by immunoaffinity chromatography from decidua collected in the first trimester of pregnancy, and the molecular weight was estimated to be approximately 140 kDa. These findings indicate that the S2n8 antigen is a useful cell surface marker for stromal cells/decidual cells and is associated with their differentiation.

Animals↗
PubMed1995

A porcine homolog of human integrin alpha 6 is a differentiation antigen of granulosa cells.

To search for new molecules relating to the mechanism(s) of follicular differentiation, we raised a new monoclonal antibody (mAb), POG-2, which reacted with the surface of porcine ovarian granulosa cells. An immunohistological study revealed that the antigen appeared initially on the primary follicles. The antigen expression increased during follicular development, reached the highest level in small follicles 1-2 mm in diameter, and then decreased in the preovulatory follicles. The antigen was not detected on luteal cells in the CL. SDS-PAGE profiles of POG-2 antigen purified from isolated porcine granulosa cells by immunoaffinity chromatography indicated that it consisted of two proteins (120 and 130 kDa) and that the antigenic epitope of POG-2 was on the 120-kDa protein. We next purified a large amount of POG-2 antigen from the homogenate of porcine ovaries by immunoaffinity chromatography. Analysis of the partial amino acid sequence of the 120-kDa protein showed that 16 amino acids from the amino terminus were very similar to those of both human and murine mature integrin alpha 6, with 88% homology. SDS-PAGE profiles revealed that the 120-kDa protein was bound to a 28-30-kDa protein by a disulfide bond; this was compatible with the reported characteristics of human integrin alpha 6. We then examined the immunoreactive distribution of integrin alpha 6 using anti-integrin alpha 6 mAb GoH3. The staining profiles obtained with GoH3 were very similar to those obtained with POG-2. These findings showed that the molecule detected by POG-2 was a porcine homolog of human integrin alpha 6 and that integrin alpha 6 was a differentiation antigen of porcine granulosa cells, suggesting an involvement of integrins in follicular differentiation.

Amino Acid Sequence↗
PubMed1995

Three-dimensional imaging diagnosis for cranial base lesions.

Diagnosis of neurological disease by imaging has greatly improved in recent years. Precise morphological information can be obtained by computed tomography and magnetic resonance imaging, and biochemical or electrophysiological dynamic changes can be assessed by positron emission tomography or magnetoencephalography. The transcription of such biochemical or electrophysiological data on computed tomographic scan or magnetic resonance imaging can precisely demonstrate the local dynamic information in the brain. Three-dimensional imaging also provides accurate intelligence on the morphological structure of lesions and facilitates the surgical management. In this article the recent technology of three-dimensional imaging diagnosis in skull base surgery is reported.

Brain Neoplasms↗
PubMed1995

A new approach to control central deafferentation pain: spinal intrathecal baclofen.

Baclofen, an agonist of the gamma-aminobutyric acid (GABA) receptor, has antinociceptive effects, and its intrathecal administration reduces allodynic responses in animal models of neurogenic central pain. Such experimental studies lead to the hypothesis that neurogenic pain may be induced in part by functional abnormalities in spinal GABAergic systems. However, whether a GABAergic system is actually involved in human central pain is unknown. The authors investigated the effect of an intrathecal bolus injection of baclofen in 14 patients with central pain due to a stroke or spinal cord injury. Nine reported substantial pain relief they had never experienced previously. The effect appeared 1-2 h after the injection and persisted for 10-24 h. Allodynia and hyperalgesia, if present, were relieved as well. Pinprick and light touch sensations did not change in nonaffected regions. The results indicate that dysfunction of spinal GABAergic systems plays a role in the clinical expression of central pain. In clinical situations, continuous intrathecal infusion of baclofen seems feasible for relief of central pain.

Afferent Pathways↗
PubMed1995

The antitumor activity of the DNA fraction from Mycobacterium bovis BCG (MY-1) for glioblastoma.

The antitumor activity of the DNA fraction extracted from Mycobacterium bovis BCG (MY-1) for glioblastoma was investigated in the experimentally produced brain tumor in rats. The tumor-bearing rats were given intralesional injection of 1 mg of MY-1 twice a week for three weeks, and were sacrificed for comparison with those of control rats. The main macroscopic features of the tumors treated with serial injections of MY-1 were cystic and destructive structures, which were histologically characterized by multiple microcysts containing macrophages. Furthermore, infiltration of leukocytes as well as the perivascular cuffing in the marginal area was observed. These findings suggested that the serial injections of MY-1 into the brain tumor have the therapeutic potential for glioblastoma.

Animals↗
PubMed1995

Inhibin alpha, beta A subunit and activin type II receptor mRNAs are expressed in human brain tumors.

Inhibin and activin were initially isolated as regulators of pituitary or gonadal hormone and are now known to be growth factors belonging to the TGF-beta family with diverse influences on the differentiation and proliferation of various tissues. To investigate the role of inhibin and activin in human brain tumors, the expression of inhibin alpha, and beta A mRNA as well as activin type II receptor (ACTR II) mRNA were studied in various human brain tumors. The tumors were divided into the following 4 groups: 3 Rathke's cleft cysts and 2 craniopharyngiomas (group 1), 8 meningiomas (group 2), 8 malignant gliomas (group 3), and various other tumors including 1 each of germinoma, astrocytoma, hemangioblastoma, and osteochondroma as well as 2 malignant lymphomas and 2 metastatic squamous cell carcinomas (group 4). Immediately after resection, tumor tissues were homogenized in guanidine thyiocyanate to extract total RNA. PCR was then performed with reverse-transcribed cDNA and the respective amplification primers. DNA bands were obtained by agarose gel electrophoresis. Messenger RNA for the inhibin beta A subunit was demonstrated in all of the tissues studied. In contrast, inhibin alpha subunit mRNA was expressed in 60%, 50%, 75%, and 75% of the tumors in groups 1, 2, 3 and 4, respectively, whereas ACTR II mRNA was demonstrated in 20%, 37.5%, 62.5% and 50% of the tumors in each group. Coexpression of mRNAs for the inhibin alpha, and beta A subunits and ACTR II occurred in some brain tumors. The levels of inhibin alpha and ACTR II mRNA tended to be higher in the tumors with a higher grade of malignancy.(ABSTRACT TRUNCATED AT 250 WORDS)

Activin Receptors↗
PubMed1995

Transcavernous surgery; an effective treatment for pituitary macroadenomas.

The endocrinological outcome in four patients with pituitary macroadenomas laterally invading the cavernous sinus, who were treated surgically by the transcranial transcavernous approach, was compared with that in four patients with macroadenomas that had been removed transsphenoidally. The decrease in the elevated serum levels of anterior pituitary hormones after transcavernous surgery ranged from 58.4% to 90.1%, whereas after transsphenoidal surgery it ranged from 0% to 46.1%. The responsiveness of pituitary hormones to stimulation tests was restored and maintained after transcranial transcavernous surgery. Transsphenoidal surgery achieved neither sufficient tumor reduction nor produced a satisfactory endocrinological remission. When cavernous sinus invasion is suspected by magnetic resonance imaging, even if it cannot be confirmed with certainty, transcranial transcavernous surgery is recommended. It is a useful surgical procedure for obtaining a sufficient degree of tumor extirpation and satisfactory endocrinological improvement in patients with macroadenomas laterally invading the cavernous sinus, particularly somatotroph or corticotroph macroadenomas. Postoperatively, mild cranial nerve paresis may occur, but this may resolve in 1-4 months.

Adenoma↗
PubMed1995

[Studies on factors influencing the attack of subarachnoid hemorrhage during labor].

We analyzed factors affecting attacks of subarachnoid hemorrhage (SAH) retrospectively in 411 patients and studied the relation of the attacks with labor. The onset time of SAH has two peaks of the time: one is 7:00 a.m. and the other is between 16:00 and 17:00 in the afternoon. The attacks of SAH during labor were observed in 15.1% of all the patients. It was noted that 66.7% of all the attacks were observed at the time with certain external stress such as working, sporting, sexual intercourse, etc. The number of patients who suffered from attacks during labor with history of hypertension and insomnia were not significantly different compared with those suffered from attacks during other activities, but 40-59 aged men those who have a history of smoking were significantly more in number compared with those that suffered attacks during other activities. Transient increase of blood pressure due to external stress is suggested as an initiative factor of the bleeding during working. Reactivity of the individuals against physical and mental stress (external stress) might be considered to be the major problem, although it remains not to be unexplained whether labor itself participates in the onset of SAH. Regarding the prevention of SAH during labor, new methods of medical examination and health control is required.

Adult↗
PubMed1995

Functional changes in cultured strips of canine cerebral arteries after prolonged exposure to oxyhemoglobin.

The present study was undertaken to determine whether oxyhemoglobin (OxyHb) is responsible for the functional alterations in the cerebral arteries observed during chronic vasospasm after subarachnoid hemorrhage. Vascular strips of canine basilar arteries were kept in organ culture for 3 days with or without repetitive exposure to OxyHb (OxyHb-treated and control strips). Contractions elicited by high levels of potassium (80 mM) and uridine 5'-triphosphate (3 x 10(-4) M) were reduced in the OxyHb-treated group in a concentration-dependent manner. The relaxations evoked by nitric oxide and 8-bromo-cyclic guanosine monophosphate (8-bromo-cGMP) were not affected. Relaxations elicited by the calcium channel blocker, diltiazem, were attenuated in the OxyHb-treated rings. When the extracellular calcium concentration ([Ca2+]e) was changed from a concentration in the external solution of 10(-8) M to 10(-3) M, myogenic tension developed. Myogenic tension, expressed as a percentage of the maximum contraction in each segment, was augmented in the OxyHb-treated group at [Ca2+]e of 10(-5) M and 10(-4) M. There were no significant differences in passive compliance of the arterial wall between the two groups. These results demonstrated that prolonged exposure to OxyHb in vitro results in a decrease in contractile capacity and an increase in sensitivity to [Ca2+]e, in agreement with previous findings in spastic arteries. By contrast, impairment of the 8-bromo-cGMP-mediated relaxation pathway and increased stiffness of the arterial wall, which have been reported to occur in spastic arteries, were not induced by prolonged exposure to OxyHb in vitro.

Analysis of Variance↗
PubMed1995

[Cooperative multicentric study on posttraumatic epilepsy].

A multicenter cooperative study was conducted to investigate factors influencing posttraumatic epilepsy (PTE) and to evaluate the prophylactic effect of anticonvulsants. A retrospective study of 102 PTE patients revealed the following typical clinical features: occurrence in young males, traffic accidents, contusion and/or cerebral hematoma. The latent period after the injury was longer in children. The percentage of EEG paroxysmal activity gradually increased as the generalized abnormality diminished. A retrospective-prospective study of 1998 patients who suffered a head injury between 1984 and 1988 was conducted till 1994. During the follow-up period, 62 patients (3.1%) developed PTE. The drop-out cases were excluded, and the 154 cases followed at least two years were analyzed. Statistical analysis of differences between patients with and without PTE suggested following factors: young, immediate early epilepsy (within 24 hours after injury; IMEE) and early epilepsy (within one week after injury). The risk with the highest relative risk rate was early epilepsy. Multiple regression analysis revealed that three factors, IMEE, early epilepsy and young age, contributed to the prediction of PTE. There was no significant difference in the percentage of patients having PTE in the group treated with anticonvulsants and the untreated group. Anticonvulsant treatment after head injury was unlikely to have a prophylactic effect on the development of PTE.

Adolescent↗
PubMed1995

[The effects of treatment with lipopolysaccharide on responsiveness of rat blood vessels].

Effects of treatment with lipopolysaccharide (LPS) both in vivo (intraperitoneal administration of 20 mg.kg-1 LPS for 6 hours) and in vitro (incubation with 1 microgram.kg-1 LPS for 6 hours) on the responsiveness of the rat thoracic aorta, carotid, renal, femoral, mesenteric, pulmonary arteries, and the femoral and mesenteric veins were examined. Intraperitoneal administration of LPS did not change the blood pressure of rats, but increased the heart rate significantly. The same amplitude of relaxation was produced by L-arginine in the aortic strips treated by LPS in vivo and in vitro, and the responses were inhibited by NG-nitro-L-arginine (L-NOARG). The contractile responses to phenylephrine in the aortic strips were reduced by LPS-treatment in vivo or in vitro, but the extent of inhibition was greater in vivo than in vitro. Further, the attenuation of contractile responses to phenylephrine was completely reversed by L-NOARG in the strips treated with LPS in vitro, whereas the reversal by L-NOARG was incomplete in the strips treated with LPS in vivo. Different amplitudes of relaxations were also produced by L-arginine or SNP in the blood vessels treated by LPS in vivo or in vitro. However, the tail artery treated with LPS in vivo or in vitro did not relax in response to L-arginine but did produce a relaxation to SNP. These results suggest that the hyporesponsiveness of rat blood vessels after treatment with LPS in vivo or in vitro may be related to an enhanced NO production in the smooth muscle cells and that there is a possible heterogeneity of regional induction or activation of L-arginine/NO pathway by LPS in rat blood vessels.

Animals↗
PubMed1995

Immunohistochemical and electron microscopic study of subependymal giant cell astrocytoma.

Six cases of subependymal giant cell astrocytoma (SGCA), five associated with tuberous sclerosis (TS), were reviewed by light microscopy, electron microscopy and immunohistochemistry. Histologically, all cases showed features typical of SGCA. GFAP and neurofilament expression were found in all cases. Synaptophysin and myelin basic protein were positive in single different cases. The MIB-1 positive rate was 0% in 4 cases, 3% in a case with recurrence after a partial resection, and 6.4% in another case with a rapid growing tumor. By electron microscope, glial filament was identified in the tumor cells of all cases, whereas none of them showed any ultrastructural evidence of a neuronal origin. We therefore suggest that SGCA is a glial origin tumor, arising from the astrocytic part of a subependymal nodule--the most common cerebral lesion of tuberous sclerosis caused by distorted migration of the germinal mantle-the neuronal part of which remains as entrapped remnants of dysgenetic, incompletely expressed neuronal cells.

Adolescent↗
PubMed1994

Selective inhibition of sympathetic nerve-mediated contraction by L-arginine in lipopolysaccharide-treated tail artery of rats.

The effects of L-arginine on the adrenergic responses to either electrical transmural stimulation or phenylephrine were studied in isolated endothelium-denuded strips of rat tail arteries treated with lipopolysaccharide for 6 h in vitro. L-arginine did not relax the strips precontracted by phenylephrine. However, the adrenergic contractions induced by electrical transmural stimulation were significantly inhibited by the addition of L-arginine. This inhibitory effect was reversed by NG-nitro-L-arginine (a nitric oxide synthase inhibitor) or methylene blue (a soluble guanylate cyclase inhibitor) but was not affected by hemoglobin (a scavenger of nitric oxide). These results indicate that the adrenergic neurogenic contractions may be directly modulated by nitric oxide derived from the sympathetic nerves and/or neighboring cells in the lipopolysaccharide-treated rat tail arteries, and the nitric oxide production may be associated with the reduction of sympathetic tone in sepsis.

Amino Acid Oxidoreductases↗