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Biomedical subjects

N Morioka

Publications and source records attributed to N Morioka.

At least 19 recordsLinked to original sources
PubMed2000

Changes in nocturnal melatonin secretion in perimenopausal women: correlation with endogenous estrogen concentrations.

Although age-related decrease in melatonin secretion in humans and animals is well documented, there is a paucity of data on the precise changes in melatonin secretion that occur during the perimenopausal period. The present study was designed to measure changes in nocturnal melatonin and to characterize the role played by estrogen in controlling nocturnal melatonin secretion in perimenopausal women. Nocturnal serum melatonin concentrations were determined every 2 hr in 46 premenopausal women, 44 postmenopausal women, and 11 premenopausal women with uterine leiomyoma scheduled for hysterectomy and bilateral salpingo-oophorectomy. Nocturnal serum melatonin secretion in premenopausal women declined moderately from 17 to 45 years of age, and increased during the period from 46 to 50 years of age. Among postmenopausal women, a steep, age-related decline in nocturnal melatonin secretion was found for up to 15 years postmenopause, followed by an extremely gradual decline thereafter. A significant negative correlation was observed between the peak serum melatonin concentration and the serum 17 beta-estradiol concentration in premenopausal women aged 40-50 years (r = -0.661, P<0.0005). Daily oral administration of conjugated estrogen (0.625 mg) to postmenopausal women suppressed nocturnal melatonin secretion (P<0.005). A low estrogen state, induced by oophorectomy of premenopausal women with uterine leiomyoma led to an increase in nocturnal melatonin secretion (P<0.0001). Our findings suggest that transient elevated nocturnal melatonin secretion during menopause may be related to the existence of a low estrogen environment. The age-related decrease in melatonin secretion observed in other conditions is most likely attributable to other age-related factors.

Adolescent↗
PubMed2000

[Neural-immune interactions in dorsal root ganglia].

Interleukin-1 (IL-1) beta is a proinflammatory cytokine that is produced by a large variety of cells, including macrophages, fibroblasts, mesangial cells and endothelial cells, and is believed to play important roles in the inflammatory responses, including hyperalgesia. Hyperalgesia is characterized by intensified pain with a reduced threshold to somatic stimulation, and it is involved in chronic inflammatory disease. Substance P (SP), an undecapeptide, has been shown to relay noxious signals as a neurotransmitter in primary afferent neurons. Thus it is expected that the change of neuropeptide activities in primary afferent neurons is attributed to inflammatory hyperalgesia by IL-1 beta. In our recent studies, IL-1 beta was found to stimulate SP release from cultured dorsal root ganglion cells via the cyclooxygenase system. These studies provide a new insight in the neural-immune intercommunication involved in the pain-regulation system observed in inflammation-induced hyperalgesia.

Animals↗
PubMed1999

Changes in nocturnal pineal melatonin synthesis during the perimenopausal period: relation to estrogen levels in female rats.

To evaluate changes in melatonin synthesis during the perimenopausal period in the female rat and to determine the effects of estrogen on melatonin synthesis, pineal levels of tryptophan, melatonin and norepinephrine and activities of N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT) were determined. Homogenates for assay were prepared from the pineal glands of female virgin Sprague-Dawley rats between 4 and 24 months of age in the middle of the dark period of a daily light/dark cycle. Serum 17 beta-estradiol (E2) concentrations were also determined. Pineal melatonin levels significantly decreased from month 4 12 and significantly increased from month 12 16, decreasing thereafter. Serum E2 concentrations significantly decreased from month 12-16, and remained low thereafter. No significant changes in tryptophan or norepinephrine were seen. NAT activities paralleled the time course of changes in melatonin. HIOMT activities decreased gradually from month 4 24. Subcutaneous implantation of an E2 capsule between months 12 and 16 resulted in significant decreases in levels of melatonin and NAT activity at month 16. Ovariectomy at month 4 or 12 led to significant increases in the levels of melatonin and NAT activity. These findings represent a temporal increase in pineal melatonin synthesis during the perimenopausal period, and suggest that the increase in melatonin synthesis activity at that time might result from decreasing levels of endogenous estrogen. The effect of estrogen on melatonin synthesis appeared to involve modulation of NAT activity.

Acetylserotonin O-Methyltransferase↗
PubMed1999

Melatonin inhibits the vasorelaxant action of peroxynitrite in human umbilical artery.

We evaluated the antioxidant property of melatonin as it relates to the vasorelaxant effect of peroxynitrite (ONOO ), a reaction product of superoxide anion radical (O2(-*)) and nitric oxide (NO), on the human umbilical artery. Helical sections of umbilical arteries were obtained from human placentas at elective cesarean delivery between weeks 37 and 39 of gestation. Changes in maximal tension induced by potassium chloride were measured in arterial sections with intact endothelium. Sections were treated with 3-morpholinosydomine (SIN-1), which releases O2(-*) and NO simultaneously, with or without pre-treatment either with hemoglobin (3 microM) or melatonin (0.1-10 microM). SIN-1 produced a significant dose-dependent relaxation of vascular tension. Pre-treatment with hemoglobin did not affect SIN-1-induced relaxation. Melatonin significantly reduced the vasorelaxant effect of SIN-1 in a concentration-dependent manner. These findings indicate that ONOO attenuates vascular tension in the human umbilical artery. Melatonin significantly suppressed the vasorelaxant effect of SIN-1, possibly due to its ability to scavenge ONOO-.

Antioxidants↗
PubMed1999

Melatonin protects against age-related DNA damage in the brains of female senescence-accelerated mice.

We investigated whether melatonin reduces the age-related susceptibility of brain to oxidative DNA damage. Brain tissues and blood samples were obtained in the middle of dark period of the daily light:dark cycle from female senescence-accelerated mice (SAM-P/6) at ages 4, 8, and 12 months. Serum melatonin concentrations and the contents of deoxyguanosine (dG) and 8-hydroxydeoxyguanosine (8-OHdG) in DNA extracted from these brain homogenates were measured by high-performance liquid chromatography. Contents of 8-OHdG showed a significant age-related increase (P < 0.001) while that of dG did not. The 8-OHdG:dG ratio also exhibited a significant age-related increase (P < 0.001). Serum melatonin concentration decreased markedly between 8 (159.7 +/- 4.5 pg/mL) and 12 (46.8 + 4.5 pg/mL) months of age (P < 0.0001). Oral melatonin administration (2 microg/mL in water) starting at 8 months of age, which produced a significant increase in serum melatonin concentration at 12 months (187.6 +/- 18.3 pg/mL) compared with untreated animals (P < 0.0001) also resulted in significant decreases in brain 8-OHdG contents and 8-OHdG:dG ratios. These results indicate that administration of a physiologic dose of melatonin to SAM-P 6 mice may prevent the age-related oxidative DNA damage in the brain.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1999

Interleukin-1beta induces substance P release from primary afferent neurons through the cyclooxygenase-2 system.

Substance P (SP) is synthesized in the dorsal root ganglion (DRG) and released from primary afferent neurons to convey information regarding noxious stimuli. The effects of the proinflammatory cytokine interleukin-1 (IL-1) beta on the release of SP were investigated using primary cultured rat DRG cells. Recombinant mouse IL-1beta added to the cells at 0.1 ng/ml increased the SP-like immunoreactivity (SPLI) in the culture medium after incubation for 6 h by approximately 50% as compared with that of nontreated DRG cells. The effect of IL-1beta was Ca(2+)-dependent and significantly inhibited by 100 ng/ml IL-1 receptor-specific antagonist (IL-1r antagonist), cyclooxygenase (COX) inhibitors such as 0.1 mM aspirin, 1 microg/ml indomethacin, and 1 microM NS-398 (specific for COX-2), and 1 microM dexamethasone. Furthermore, a 1-h incubation with IL-1beta markedly increased the inducible COX-2 mRNA level, which was inhibited by an IL-1r antagonist and dexamethasone, whereas IL-1beta showed no effect on the level of constitutive COX-1 mRNA. These observations indicated that IL-1beta induced the release of SP from the DRG cells via specific IL-1 receptors, the mechanism of which might involve prostanoid systems produced by COX-2. This could be responsible for the hyperalgesic action with reference to inflammatory pain in the primary afferent neuron to spinal cord pathway.

Animals↗
PubMed1999

[Catecholestrogen].

Explore the source record for details and available documents.

Estrogens, Catechol↗
PubMed1998

Primary ovarian angiosarcoma: a case report and literature review.

Primary ovarian angiosarcoma is extremely rare. Only 16 cases have histologically been reported to date in the literature. A case of angiosarcoma arising in the right ovary of a 46-year-old female is presented. Grossly, the resected right ovary was completely replaced by a solid tumor mass, which revealed multiple necrotic and/or hemorrhagic foci. This case revealed the typical histological features of angiosarcoma with sinusoidal and solid patterns of anaplastic tumor cells. Immunohistochemically, tumor cells were strongly and diffusely positive for CD31 and CD34, in particular, along the cytoplasmic membrane of the tumor cells. Ultrastructurally, tumor cells possessed the intermediate junctions between tumor cells, discontinuous basal laminae attached to the irregularly shaped blood vessels and occasional cytoplasmic pinocytotic vesicles. These findings confirmed the case as being one of angiosarcoma of the ovary. The patient died 9 months after surgery as a result of developed multifocal brain metastases. A total of 17 cases reported as primary ovarian angiosarcoma, including this presented case, are clinicopathologically reviewed.

Antigens, CD34↗
PubMed1998

Effect of estrogen on melatonin synthesis in female peripubertal rats.

Our objective was to evaluate the effect of estrogen on the synthesis of melatonin in female rats during the peripubertal period. The level of melatonin and of N-acetyl serotonin (NAS) and the activity of N-acetyltransferase (NAT) and of hydroxy-indole-O-methyltransferase (HIOMT) were determined in homogenates of pineal glands from peripubertal female Sprague-Dawley rats in the mid-dark during the daily light/dark cycle between 4 and 10 weeks of age. Ovariectomy was performed and daily administration of estradiol benzoate (E2B) was initiated at 6 weeks of age. A peak in the pineal level of melatonin and NAS and in NAT activity was observed in untreated (control) rats with intact ovaries at 6 weeks. Thereafter, HIOMT activity increased and remained unchanged. Ovariectomy at week 6 led to significant increases in the level of melatonin and of NAS and in NAT activity at week 8. At week 10, NAT activity was similar to that of control animals, but melatonin and NAS levels were slightly elevated. Ovariectomy did not affect HIOMT activity. The subcutaneous injection of a low dose (0.1 microg/day) of E2B suppressed the ovariectomy-induced elevation of levels of melatonin and NAS and of NAT activity, similar to that seen in rats with intact ovaries. A higher dose of E2B (1.0 microg/day) reduced the activity of NAT and HIOMT to values significantly below the control values. Results suggest that estrogen modulates the nocturnal synthesis of melatonin by the pineal gland in peripubertal female rats. The decline in melatonin synthesis during puberty may be related to an increase in the estrogen level. The inhibitory effect of estrogen in melatonin synthesis appeared to be mediated by the modulation of NAT activity.

Acetylserotonin O-Methyltransferase↗
PubMed1998

Estrogen modulates the nocturnal synthesis of melatonin in peripubertal female rats.

Our objective was to evaluate the effects of estrogen deficit and of estrogen stimulation on the synthesis of pineal melatonin in female rats during the peripubertal period. The levels of melatonin and N-acetylserotonin (NAS) and the activities of N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT) were determined in homogenates of pineal glands obtained from peripubertal female Sprague-Dawley rats 4 to 12 weeks of age in the mid-dark during the daily light/dark cycle. Animals were ovariectomized at 4 weeks of age; daily administration of estradiol benzoate (E2B, 1.0 microg/d, s.c.) was initiated at 4 weeks of age. A peak in the pineal levels of melatonin and NAS and in NAT activity was observed in untreated (control) rats with intact ovaries at 6 weeks. HIOMT activity increased from Week 4 to 6 and remained unchanged thereafter. Ovariectomy at Week 4 led to significant increases in the levels of melatonin and of NAS and NAT in activity at Week 8. NAT activity Week 10 resembled that of control animals, but levels of melatonin and NAS were slightly elevated. Ovariectomy did not affect HIOMT activity. Subcutaneous injection of E2B significantly decreased the levels of melatonin and NAS and of NAT activity at Week 4, as compared with those in control rats. E2B suppressed the ovariectomy-induced elevation of levels of melatonin and NAS and of NAT activity, similar to the effect in control animals. E2B did not affect HIOMT activity. Our results suggest that estrogen modulates the nocturnal synthesis of melatonin in the pineal gland in peripubertal female rats. The effects of estrogen on melatonin synthesis appeared to be mediated by the modulation of NAT activity.

Acetylserotonin O-Methyltransferase↗
PubMed1998

Coronary vasospasm at the site of myocardial bridge--report of two cases.

Two patients with angina pectoris and postmyocardial infarction angina due to coronary vasospasm at the site of myocardial bridge are described. Intracoronary injection of isosorbide dinitrate led to resolution of coronary vasospasm on acetylcholine provocation test, and vasospastic angina pectoris has been well controlled after treatment with calcium channel blockers.

Angina Pectoris↗
PubMed1998

[PARAGRAPH as a neuromuscular blockade monitor].

To assess the clinical performance of a new neuromuscular blockade monitor "PARAGRAPH", we studied adults and pediatric patients during general anesthesia. PARAGRAPH enables anesthesiologists to perform various types of assessment of neuromuscular blockade, including TOF, DBS and single twitch even with children. The most remarkable point is its capability for analysis and printing by personal computer. We conclude this device is portable and easy to use, as well as a clinically reliable neuromuscular blockade monitor.

Adult↗
PubMed1998

[Transdermal nitroglycerin before induction of anesthesia prevents redistribution hypothermia in patients under general anesthesia].

Initial anesthesic-induced hypothermia results largely from core-to-peripheral redistribution of heat. Administration of transdermal nitroglycerin induces vasodilation. Such vasodilation, induced well before induction of anesthesia, might redistribute heat to peripheral tissues. Minimal redistribution hypothermia might accompany subsequent induction of anesthesia. We studied 32 patients undergoing gastrointestinal surgery. Thirty minutes before induction of anesthesia, they were randomly assigned to: 1. transdermal nitroglycerin 10 mg; 2. transdermal nitroglycerin 5 mg; and, 3. control. Core temperature during the first hour of anesthesia decreased significantly more in the control patients than in those given either dose of nitroglycerin. Vasodilation induced by transdermal nitroglycerin before induction of anesthesia significantly decreased subsequent redistribution hypothermia. Drug-induced modulation of vascular tone thus produces clinically important alterations in intraoperative core temperature.

Administration, Cutaneous↗
PubMed1997

Nocturnal changes in pineal melatonin synthesis during puberty: relation to estrogen and progesterone levels in female rats.

Our objective was to evaluate the changes in melatonin synthesis during the peripubertal period in the female rat and to determine the effects of ovarian steroid hormones on melatonin synthesis. Pineal levels of tryptophan, 5-hydroxytryptamine (5-HT), melatonin and norepinephrine were determined in female Sprague Dawley rats (between 2 and 12 weeks of age) in the mid-dark during the daily light/dark cycle. Melatonin levels increased with age, parallel to pineal growth, until 6 weeks of age, when the vaginal opening was found in 66.7% of rats, and significantly decreased until 8 weeks of age, when the vaginal opening was found in all rats. Norepinephrine began to increase earlier and reached a mature level at 4 weeks of age. Treatments with bilateral ovariectomy at 4, 6, and 8 weeks of age resulted in significant increases in melatonin and 5-HT levels, and significant decrease in tryptophan level at 2 weeks after ovariectomy. Treatments with ovariectomy at 6 weeks of age produced a consistent increase in 5-HT level and a consistent decrease in tryptophan level until 6 weeks after ovariectomy. However, melatonin levels increased until 2 weeks after ovariectomy, then decreased and reached a control level at 6 weeks after ovariectomy. Subcutaneous implantation of estradiol-17 beta capsule and daily subcutaneous injection of estradiol benzoate (E2B) (1.0 microgram, 20 micrograms) for two weeks in the rats ovariectomized at 4, 6, and 8 weeks of age resulted in significant decreases in melatonin and 5-HT levels and a significant increase in tryptophan level at 2 weeks after ovariectomy. A smaller dose of E2B (0.1 microgram) produced the same effects in the rats ovariectomized at 4, but not at 6 and 8 weeks of age. Administration of progesterone (200 micrograms/day) for 2 weeks did not produce any significant changes in melatonin, 5-HT, and tryptophan levels. Norepinephrine levels were not changed by any of the above treatments. These results suggest that estrogen, but not progesterone, can modulate nocturnal pineal melatonin synthesis in peripubertal female rats, and that the decline in the melatonin synthetic activity during the pubertal period might be related to the increasing levels of endogenous estrogen, which is secreted from the maturing ovary. The sites of action of the inhibitory effect of estrogen on the pineal melatonin synthesis may be multiple.

Age Factors↗
PubMed1995

Cytotoxic T cell recognition of a human melanoma derived peptide with a carboxyl-terminal alanine-proline sequence.

Recently, we defined the antigenic epitope recognized by the human monoclonal antibody L94 to be a protein with a C-terminal sequence of alanine-proline (AP). An antigenic peptide no. 707 (RVAALARDAP), which was identified by the use of cDNA libraries of an antigen positive melanoma cell line M14, was evaluated for cellular immune responses in melanoma patients. PBMC from 16 of 19 melanoma patients were shown to lyse autologous B lymphoblastoid cell lines (BCL) pulsed with synthetic peptide no. 707 (hereafter no. 707). This specific cytotoxicity to the peptide significantly increased in 84% of melanoma patients after in vivo immunization with a melanoma cell vaccine (MCV). In contrast, peptide specific cytotoxicity was observed in only one of 19 normal volunteer donors. In vitro restimulation of MCV treated patients' PBMC with no. 707 augmented cytotoxicity against autologous no. 707-pulsed BCL. This cytotoxicity was specific to the C-terminal sequence AP, since the removal of C-terminal AP completely abolished the specific lysis. no. 707 restimulation of PBMC enhanced cytotoxicity against autologous melanomas. Autologous melanoma and peptide-pulsed BCL targets were lysed by CD8+CTL in a HLA class I-restricted manner. The strong cytotoxicity was obtained from patients of HLA A24. CTL lysis of autologous no. 707-pulsed BCL was partially blocked by unlabeled autologous melanomas in a cold target inhibition test. This suggested that the epitope identical or cross-reactive to no. 707 may be presented on the melanoma cell surface by HLA class I antigens. Our findings suggest that peptide no. 707 presented on human melanoma cells is recognized by CTL and that C-terminal AP plays a critical role in both antibody and T cell recognition.

Alanine↗
PubMed1995

[Physical properties of Strecker stents].

Strecker stent is a balloon-expandable metallic stent that is made of knitted tantalum wire mesh in order to Maintain flexibility. Therefore, the prosthesis is well suited to irregular and tortuous tube organs. We performed several physical experiments using 8 mm and 6 mm diameter stents made of 0.1 mm diameter wire filament. The bearing power of the 8 mm diameter stent against the circumferential compression pressure was divided into two groups, that is, 77-100% and under 66% of expansile rate. The capacity bearing the circumferential compression pressure of the latter group was greater than that of the former. Further, the bearing power of the 6 mm diameter stent was greater than that of the 56% expansile rate of the 8 mm diameter stent. The smaller the expansile rate of the stent, the smaller the minimum radius of curvature within the limits of the stent's plastic. To evaluate the suitability of the stent in clinical use, we made two projections on the inner surface of rubber tubes, and the stents were placed into the rubber tubes at different expansile rates. We evaluated the degree of contact of the stents against the rubber wall by taking soft X-ray photographs. The stents showed good suitability under the condition of incomplete expansion. For the above reasons, we concluded that, from the view-point of bearing power, the stent should be placed in the full expansile state. From the viewpoint of contact against the vessel wall, the stent should be placed in the incomplete expansile state.

Physical Phenomena↗
PubMed1995

[Percutaneous placement of intraluminal stent-graft for aortic dissection: experimental study].

Highly porous fabric vascular grafts fabricated of ultrafine polyester fibers (UFPF-graft; porosity, 7,000 ml, 9,000 ml, 11,000 ml at 120 mmHg) were attached between two Gianturco stents connected with two stainless steel struts. UFPF-grafts with two Gianturco stents were placed into the aortas of six adult mongrel dogs without firm contact with the luminal surface. From two days to four months after placement, all the UFPF-grafts were completely sealed with fresh thrombus or neointima. Within two months, complete endothelialization was observed on both surfaces of the neointima. In three dogs, aortic dissections were created experimentally. Then an UFPF-graft (porosity, 9,000 ml) with two Gianturco stents was placed at the site of entry of the dissection, followed by additional Gianturco stents to expand the UFPF-graft. X-ray angiography showed that the entries were closed immediately after placement, and false lumens disappeared within one hour after placement. These results indicated that the method has the possibility of treating aortic dissection with complete sealing of the fabric by the neointima.

Aortic Dissection↗