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Biomedical subjects

H Okamura

Publications and source records attributed to H Okamura.

At least 433 records · Page 24Linked to original sources
PubMed1993

Differential expression of serotonin and [Met]enkephalin-Arg6-Gly7-Leu8 in neurons of the rat brain stem.

The hypothesis that serotonin (5-HT) and [Met]enkephalin-Arg6-Gly7-Leu8 (MEAGL) coexist in the rat brain stem raphe nuclei was tested by a technique combining histofluorescence with immunocytochemistry, after treatment with colchicine and nialamide. In midbrain and pons serotonergic cell groups (B5-B9), no coexistence of 5-HT and MEAGL was detected. In serotonergic cell groups of the medulla oblongata (B1-B3), only 0.3-1.5% of 5-HT-fluorescent cells were MEAGL-immunoreactive. These findings suggest that putative 5-HT and MEAGL are mostly expressed in different populations of neurons in the rat raphe nuclei.

Animals↗
PubMed1993

The direct retinal projection to VIP neuronal elements in the rat SCN.

The connection between optic nerve terminals and vasoactive intestinal peptide (VIP)-containing neurons in the rat suprachiasmatic nucleus (SCN) was investigated using double labeling immunocytochemistry. Cholera toxin B subunit (CT) was injected into the right eyeball, and coronal sections of the SCN were then processed for CT immunocytochemistry with silver-gold intensification and VIP immunocytochemistry consecutively with DAB staining alone. In the ventrolateral portion of the SCN, CT immunoreactive (CT-IR) optic nerve terminals were found to make synaptic contacts not only with VIP-like immunoreactive (VIP-LI) dendrites, but also with VIP-LI perikarya. CT-IR nerve endings were also found to make synaptic contacts with non-VIP immunoreactive neuronal dendrites.

3,3'-Diaminobenzidine↗
PubMed1993

Scanning electron microscopic and immunohistochemical studies of pelvic endometriosis.

The pathogenesis of pelvic endometriosis has been studied by using scanning electron and light microscopy, observing the surface structure of bluish lesions obtained from 26 patients during laparotomy. Paraffin sections included another 17 tissue samples of endometriosis, based on immunohistochemical responses to epithelial membrane antigen, keratin and vimentin. Ultrastructurally, the surface epithelial cells could not be detected in 13 out of 17 pelvic peritoneal endometriosis samples. In one case in which the surface peritoneal cells were seen histologically to dip into the subperitoneal stroma, many surface peritoneal infoldings were observed, and ciliated cells were detected at the edge of these infoldings. Ovarian endometriosis was composed of three types of cells, none of which had any cilia. These findings were observed in continuity with adjacent normal mesothelial cells. No characteristic structure of the endometrial surface was observed for the bluish lesion, but the gland surface of endometriosis located in the subperitoneal stroma initially had ciliated cells. The immunoreactions in both the columnar mesothelial cells with surface peritoneal infoldings and the glands of endometriotic tissues were similar to those of normal endometrial glands, but different from those of normal mesothelial cells. Pelvic endometriosis might originate by a process of metaplasia from the pelvic peritoneum.

Adult↗
PubMed1993

Neuronal interaction between VIP and vasopressin neurones in the rat suprachiasmatic nucleus.

Synaptic interaction between VIP-like immunoreactive (VIP-LI) and vasopressin-like immunoreactive (VASO-LI) neurones both of which are main neuronal components in the SCN was investigated using double labelling immunoelectron microscopy. VIP-LI axons were identified as having synaptic contacts with VASO-LI neuronal perikarya and dendrites. VIP-LI axons also formed synapses on non-immunoreactive dendrites or dendritic spines. In addition to the above findings, VIP-LI neuronal elements also formed synaptic contacts with other VIP immunoreactive structures.

Animals↗
PubMed1993

Pharmacologic properties of a novel Ca2+ entry blocker, AJ-2615, in vitro.

We studied the in vitro vascular relaxant properties of AJ-2615, (+/-)-N-[6,11-dihydrodibenzo[b,e]-thiepin-11-yl]-4-[4- fluorophenyl]-1-piperazinebutanamide monomaleate, a novel compound with long-lasting antihypertensive activity. AJ-2615 inhibited the high K(+)-induced contractile response in rat aorta with an IC50 of 2.08 x 10(-8) M. It was 13 times less potent than nifedipine and 3, 10, and 15 times more potent than verapamil, diltiazem, and fluanarizine, respectively. AJ-2615 also inhibited the high K(+)-induced 45Ca influx in rat aorta at almost the same concentration as that for inhibition of the contractile response. The inhibition of 45Ca influx was reversed by Bay k 8644, a Ca2+ channel agonist. The effects of AJ-2615 on the contractile response and Ca2+ influx persisted for at least 120 min after AJ-2615 was removed from the medium. These results indicate that AJ-2615 acts directly on the potential-dependent Ca2+ channel in a long-lasting manner. AJ-2615 inhibited [3H]prazosin binding to dog aortic membranes (IC50 = 1.25 x 10(-8) M) and phenylephrine-induced contractile response in superior mesenteric artery (SMA) of rabbits (IC50 = 3.87 x 10(-8) M), indicating that AJ-2615 has potent alpha 1-adrenoceptor blocking activity. AJ-2615 at 10(-6) M did not inhibit the caffeine-induced contractile response in rabbit SMA in Ca(2+)-free medium, nor did it inhibit calmodulin (CAM) activity.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1993

Purification of a factor which provides a costimulatory signal for gamma interferon production.

A protein factor which induces high levels of gamma interferon (IFN-gamma) in resting splenic nonadherent cells was isolated from the sera of mice with generalized inflammation caused by endotoxic shock. The factor was highly purified by ammonium sulfate precipitation followed by ion-exchange column chromatography on DEAE-Sepharose, molecular sieving on Ultrogel AcA 44, and hydrophobic column chromatography with phenyl-Sepharose. It was further purified to apparent homogeneity by polyacrylamide gel electrophoresis. It induced IFN-gamma production in a dose-dependent manner in the presence of interleukin-2, monoclonal anti-CD3 antibody (anti-CD3 MAb), or concanavalin A (ConA) in spleen cells deprived of plastic plate- and nylon wool-adherent cells. Anti-CD3 MAb induced the highest level of production of the three. The factor, interleukin-2, anti-CD3 MAb, or ConA alone induced a trace of or no detectable IFN-gamma in these cells. The factor also exhibited an accessory function during proliferation in these cells in the presence of a suboptimal dose of ConA. However, the factor failed to stimulate IFN-gamma production when staphylococcal enterotoxin A, a superantigenic T-cell mitogen, was employed. Treatment with pronase or heat abolished these activities. These studies confirm the existence of a soluble protein factor which is able to exhibit a novel accessory function in IFN-gamma production in resting T or natural killer cells. It will be of interest to compare this factor with the recently cloned human natural killer stimulatory factor (NKSF/IL-12).

Animals↗
PubMed1993

Normal uterus and FIGO stage I endometrial carcinoma: dynamic gadolinium-enhanced MR imaging.

Dynamic magnetic resonance (MR) imaging was performed on a 1.5-T superconducting unit for evaluation of 26 stage I endometrial carcinomas. To establish the appearance of the normal uterus, 27 normal uteri were also evaluated. After rapid injection of gadopentetate dimeglumine, dynamic images were obtained every 30 seconds with the spin-echo technique in the sagittal plane. On dynamic studies of endometrial carcinoma, the tumor-myometrial contrast was marked at 120 seconds after administration of gadopentetate dimeglumine (contrast-to-noise ratio [C/N], 26.0). The tumor-myometrial contrast on the dynamic study was more marked than that on postcontrast T1-weighted images (C/N, 10.0) and on T2-weighted images (C/N, 2.14). Dynamic and postcontrast MR images were superior in enabling differentiation of viable tumors from necrosis or residual secretion in the endometrial cavity. In the evaluation of presence of tumor and myometrial invasion, the accuracy of T2-weighted imaging and dynamic imaging was 67.9% and 84.9%, respectively.

Adult↗
PubMed1993

Hyperintense uterine leiomyoma at T2-weighted MR imaging: differentiation with dynamic enhanced MR imaging and clinical implications.

PURPOSE: To evaluate the role of dynamic enhanced magnetic resonance (MR) imaging in differentiating leiomyomas with high signal intensity at T2-weighted imaging. MATERIALS AND METHODS: Histologic features of 34 uterine leiomyomas that showed hyperintensity on T2-weighted images were compared with those of ordinary hypointense leiomyomas (n = 74). The results of treatment with gonadotropin-releasing hormone analogue were also analyzed in relation to pretreatment signal intensity. RESULTS: Degenerated leiomyomas (n = 13) had higher signal intensity and heterogeneous architecture, but there was considerable overlap in signal intensity with cellular leiomyomas (n = 21). At dynamic enhanced MR imaging, cellular leiomyomas had marked contrast enhancement in the early phase, while degenerated leiomyomas showed slight or irregular enhancement. Cellular leiomyomas were reduced significantly in size after treatment (P = .02). The response in degenerated leiomyomas was minimal. CONCLUSION: Evaluation of signal intensity at T2-weighted imaging and degree of contrast enhancement at dynamic enhanced MR imaging provide useful information on the nature of leiomyomas.

Buserelin↗
PubMed1993

Effects of progesterone and anti-progesterone RU486 on ovarian 3 beta-hydroxysteroid dehydrogenase activity during ovulation in the gonadotrophin-primed immature rat.

The effects of progesterone and RU486, a synthetic anti-progesterone, on ovarian 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) activity, a key enzyme of progesterone production, were studied during ovulation in immature 22-day-old rats primed with pregnant mares' serum gonadotrophin (PMSG) and human chorionic gonadotrophin (hCG). Ovarian 3 beta-HSD activities had increased significantly 4 h after hCG injection. These increases were inhibited at 4 and 6 h after hCG when 20 mg RU486 kg-1 was administered 2 h before hCG. However, RU486 had no influence on the activity of 3 beta-HSD when administered at the same time as hCG injection. A histochemical study revealed that 3 beta-HSD activities in the granulosa cell layer, but not in the theca cell layer, were inhibited when RU486 was given 2 h before hCG. Serum progesterone concentrations, but not oestradiol concentrations, were significantly suppressed by RU486 treatment 4 and 6 h after hCG. The effect of progesterone on ovarian 3 beta-HSD activity was tested by administering graded doses of progesterone exogenously to rats 2 h before hCG injection. Ovarian 3 beta-HSD activity was increased in a dose-dependent manner, and more than 20 mg progesterone kg-1 significantly stimulated the activity. Although 10 mg progesterone kg-1 did not stimulate ovarian 3 beta-HSD activities, the RU486-inhibited activities were recovered by the concomitant administration of 10 mg progesterone kg-1 with RU486. These results indicate that ovarian 3 beta-HSD activity depends on progesterone concentrations, and suggest an autocrine regulation of progesterone production during ovulation in immature rat ovaries stimulated with PMSG and hCG.

3-Hydroxysteroid Dehydrogenases↗
PubMed1993

Changes in adenylyl cyclase activity in human endometrium during the menstrual cycle and in human decidua during pregnancy.

Adenylyl cyclase activity was studied in human endometrium during the menstrual cycle and in human decidua during pregnancy. Higher adenylyl cyclase activity was found in the endometrium than in the myometrium, corpus luteum or Fallopian tubes. In the endometrium, the basal and stimulated activities were highest in the fundus and decreased slightly from the fundus to the isthmus. Prostaglandin-stimulated adenylyl cyclase activity increased gradually from the proliferative phase to the secretory phase, and then quickly reached its highest value in the late secretory phase. Catecholamine-stimulated adenylyl cyclase activity reached a peak in the late proliferative phase and decreased significantly thereafter. Forskolin-stimulated activity was significantly higher throughout the secretory phase than in the proliferative phase. In the decidua, prostaglandin-, catecholamine- and forskolin-stimulated adenylyl cyclase activities in late pregnancy were significantly lower than those in early pregnancy. Our results demonstrate dramatic alterations in adenylyl cyclase activity in human endometrium during the menstrual cycle and in human decidua during pregnancy.

Adenylyl Cyclases↗
PubMed1993

Association of immunolocalization of matrix metalloproteinase 1 with ovulation in hCG-treated rabbit ovary.

Matrix metalloproteinase 1, MMP-1, which was previously called interstitial collagenase, is necessary for extracellular matrix reconstruction. The immunolocalization of the latent form of MMP-1 (proMMP-1) was examined in the ovulatory process in hCG-treated (100 iu per animal) rabbit ovaries. Immunoreactive products of proMMP-1 were identified by the avidin-biotin peroxidase complex formation using an anti-rabbit proMMP-1 polyclonal antibody. ProMMP-1 was distributed in the cytoplasm of theca interna cells, theca externa cells, interstitial glands and germinal epithelium throughout ovulation. However, at 9 or 10 h after hCG treatment, this enzyme was identified in several capillary lumina around the apex of preovulatory follicles. In addition, the staining density of immunoreactive products apparently increased in granulosa cells and theca interna cells around the orifice of the ruptured follicle 10 h after the stimulation. These results indicate that the spatiotemporal appearance of proMMP-1 in ovulation may be closely associated with the initiation of rupture of the follicle.

Animals↗
PubMed1993

Assessment of myometrial invasion by endometrial carcinoma: transvaginal sonography vs contrast-enhanced MR imaging.

OBJECTIVE: A prospective study was designed to compare transvaginal sonography with contrast-enhanced MR imaging to determine preoperatively the depth of myometrial invasion in patients with early-stage endometrial carcinoma. SUBJECTS AND METHODS: In 40 patients, findings on transvaginal sonograms, unenhanced T2-weighted MR images, and contrast-enhanced T1-weighted Mr images were compared with histologic findings. The depth of myometrial invasion was classified as stage E (tumor limited to endometrium, n = 12), stage S (superficial invasion: tumor invades up to 50% of the myometrium, n = 15), or stage D (deep invasion: tumor invades more than 50% of the myometrium, n = 13). RESULTS: Findings on transvaginal sonograms were accurate in 27 of 40 patients (accuracy, 68%); the depth of invasion was overestimated in five patients and underestimated in eight patients. The results of unenhanced T2-weighted MR images were accurate in 27 patients (accuracy, 68%), with four overestimations and nine underestimations. The results of contrast-enhanced T1-weighted MR images were accurate in 34 patients (accuracy, 85%), with five underestimations and one overestimation. In the assessment of each stage of myometrial invasion, the sensitivity and specificity of contrast-enhanced T1-weighted imaging were higher than those of T2-weighted MR imaging and transvaginal sonography. The false-positive diagnoses based on transvaginal sonograms and T2-weighted images, respectively, involved polypoid tumors (n = 4 and 2), distension of the endometrial cavity by pyometra (n = 2 and 1), the presence of myoma (n = 2 and 1), atrophy of the myometrium (n = 1 and 0), and poor tumor/myometrium contrast (n = 0 and 2). On contrast-enhanced MR images, accuracy was influenced only in a case of polypoid tumor, because tumor, endometrial cavity, and myometrium were clearly distinguished and residual myometrium was clearly visualized. With all imaging techniques, false-negative diagnoses were caused mainly by tumors with superficially spreading growth or microscopic invasion. With transvaginal sonography, infiltrative tumor also tended to be understaged (n = 3). CONCLUSION: Contrast-enhanced MR imaging is significantly superior to transvaginal sonography and unenhanced T2-weighted MR imaging for detecting myometrial invasion.

Adult↗
PubMed1993

[Quantitative evaluation of X-ray opacity of the maxillary sinus using a digital disposition system].

The authors attempted to obtain a quantitative index of X-ray opacity of the maxillary sinus using a digital disposition system. X-ray films of the Waters' view were used for analysis. A cooper wedge was placed on the left side of the subject's face and was simultaneously filmed. The wedge was made of copper plates increased in thickness from 0.2 to 4.0 mm in 20 steps and serving as a calibration standard. The subject-to-film distance was kept constant at one meter. The voltage and current of the X-ray tube were 85 kV and 200 mA, respectively. The X-ray films were digitized with a film-digitizer (Toshiba, TDF-500B). The X-ray opacity from 0.0 to 4.0 was transformed to 1024 steps and the whole X-ray film was divided into 512 x 512 pixels. Then, the X-ray density of each pixel was converted to an absolute value of wedge thickness with a medical image processor (Toshiba, GMS-500U). The mean pixel values in the region of interest (ROI) of the maxillary sinus and that of the whole maxillary sinus were named MR and MW, respectively. The mean pixel value in the ROI of the ipsilateral orbita was called O. We used MR, MW, MR -O and MW -O as indices. The results were as follows: 1. MR, MW, MR -O and MW -O were useful in quantitative evaluation of the X-ray opacity of the maxillary sinus in a subject. 2. MR -O and MW -O were also good references for comparing the X-ray opacity of the maxillary sinus among different subjects.

Adult↗
PubMed1993

[The localization and the function of carbonic anhydrase in the inner ear].

Carbonic anhydrase (CA) is distributed in a wide variety of animal cells and tissues, especially in cells and tissues involved in rapid exchange or transport of protons, bicarbonate, or other ions. Although localization of this enzyme and its physiological roles in the inner ear have been investigated extensively, full clarification has yet to be achieved. We have conducted a histochemical investigation of CA localization in the inner ear of the guinea pig by Hansson's method, with emphasis on improved fixation. The histochemical reaction for CA activity is localized in the outer and inner hair cells of the organ of Corti, Deiters' cells or nerve endings, inner pillar cells, Boettcher's cells, stria vascularis, spiral ligament, vasculo-epithelial zone and spiral ganglion cells. The physiological roles of CA in the inner ear, particularly in relation to the production or absorption of endolymph, are discussed in this report.

Animals↗
PubMed1993

The properties and mec A gene of the methicillin-resistant Staphylococcus aureus isolated in Fukushima Medical College Hospital.

The 106 methicillin-resistant strains of Staphylococcus aureus (MRSA) isolated in Fukushima Medical College Hospital were examined for their properties and mecA gene. The strains produced four types of coagulase, of which type II was the most common, produced by 84 (79.2%). Beta-lactamase was produced by 58 (50%). Enterotoxins were produced by 45 (42.5%), most of which (39/106, 36.8%) were of type A. Thirty-four strains (32.1%) produced both enterotoxins and toxic shock syndrome toxin-1. All strains were susceptible to vancomycin and arbekacin, although they were mostly resistant to many other antibiotics. Using the polymerase chain reaction (PCR) technique, the mecA gene was detected in 57 (91.9%) of the 62 strains used. In addition, one of the 42 methicillin-susceptible strains isolated had the mecA gene. These results indicate that detection of the mecA gene by the PCR technique is a rapid and accurate way to identify methicillin resistance.

Bacterial Proteins↗