Biomedical subjects

I Sato

Publications and source records attributed to I Sato.

At least 127 records · Page 7Linked to original sources

PubMed1999

Intraventricular injection of melatonin inhibits naloxone-induced, but not NMDA- or LHRH-induced LH release in ovariectomized estrogen-primed rats.

The present study was aimed to examine the possible functional relationship between melatonin and hypothalamic transmitters, endogenous opioids and excitatory amino acids in controlling gonadotropin secretion in ovariectomized estrogen-primed rats. An intravenous injection of naloxone (mu opioid receptor antagonist), N-methyl-D-aspartate (NMDA; NMDA receptor agonist) or luteinizing hormone-releasing hormone (LHRH) significantly elevated serum luteinizing hormone (LH) concentrations within 10 min. An intraventricular treatment with melatonin, which did not affect the basal LH concentration by itself, significantly suppressed the effect of naloxone. However, the same melatonin treatment did not inhibit the NMDA-induced or LHRH-induced LH secretion. These results support the hypothesis that melatonin has a suprapituitary site of action to inhibit LHRH release, and suggest that the site of its action may be located downstream to that of naloxone action and upstream to that of NMDA in the hypothalamic LHRH neuronal pathway.

Animals↗

PubMed1999

Recent progress in the neurotoxicology of natural drugs associated with dependence or addiction, their endogenous agonists and receptors.

Nicotine in tobacco, tetrahydrocannabinol (delta 9-THC) in marijuana and morphine in opium are well known as drugs associated with dependence or addiction. Endogenous active substances that mimic the effects of the natural drugs and their respective receptors have been found in the mammalian central nervous system (CNS). Such active substances and receptors include acetylcholine (ACh) and the nicotinic ACh receptor (nAChR) for nicotine, anandamide and CB1 for delta 9-THC, and endomorphins (1 and 2) and the mu (OP3) opioid receptor for morphine, respectively. Considerable progress has been made in studies on neurotoxicity, in terms of the habituation, dependence and withdrawal phenomena associated with these drugs and with respect to correlations with endogenous active substances and their receptors. In this article we shall review recent findings related to the neurotoxicity of tobacco, marijuana and opium, and their toxic ingredients, nicotine, delta 9-THC and morphine in relation to their respective endogenous agents and receptors in the CNS.

Acetylcholine↗

PubMed1999

Distributions of adipocyte, blood vessel, and muscle fiber in human lateral petrygoid muscle during ageing.

The composition of adipocyte, blood vessel, and muscle fiber during ageing from 30 to 90 years of age was examined by a computer analyzing system in human lateral petrygoid muscle. The human lateral petrygoid muscle, the intramuscular connective tissue with adipocyte and blood vessel, displayed a specific change in morphology during ageing. Numerous adipocyte appeared around the blood vessel in the perimysium of the human petrygoid muscle from 60 years of age. The percentage and size of adipocyte and vein per 10,000 micron 2 of the cross sectional area in the muscle increased as well. However, the cross sectional area of muscle fiber was almost constant. The increase of adipocyte was related with changes of blood vessel and connective tissue in the perimysium.

Adipocytes↗

PubMed1999

Comparison between deciduous and permanent incisor teeth in morphology of bovine enamel.

Functional incisor teeth (deciduous and permanent teeth) from Bovidae (14 species) were prepared for scanning electron microscopic observation. Ultrastructural patterns of the enamel layer of deciduous and permanent incisor teeth varied (ex. prisms, arrangement pattern of matrices, and in thickness of enamel layer) in each species. The ultrastructures of prisms in longitudinal sections were classified into three types; A, radial, B, tangential, and C, mix of A and B arrangement enamel; modified Koenigswald's method (1982) in examined species. Type A was found in a large part of permanent and a small part of deciduous incisor teeth, while types B and C were mainly found in the deciduous teeth. These morphological features show the remarkable correlation between permanent and deciduous teeth.

Animals↗

PubMed1999

[The effect of midazolam on the memory during cesarean section and the modulation by flumazenil].

In 30 patients (ASA-1) for elective Cesarean section who had given informed consent, characteristics of amnesia induced by midazolam (M) and their modulation by flumazenil (F) were examined. Spinal anesthesia was performed with dibucaine. After the delivery, the baby was shown to the mother. Then 21 patients were given bolus intravenous injection of M until the patient got into sleep and the inhalation of nitrous oxide mixed with oxygen was started. At the end of surgery bolus injection of F 0.1 mg was cumulatively repeated until the patient awoke. Nine patients were given only nitrous oxide and oxygen inhalation after the delivery. The remembrance of the baby face and the doses of M and F were compared. In group given M, 14 patients recalled their baby's face whereas 7 did not. The average doses of M and F in patients with memory were 69 micrograms.kg-1 and 2.5 micrograms.kg-1, respectively, whereas the average dose of M and F in patients without memory were 94 micrograms.kg-1 and 4.2 micrograms.kg-1, respectively. In the patients without M injection, all could recall the face of the baby. These results suggest that M could produce retrograde amnesia, when combined with nitrous oxide inhalation, which is not reversed by F.

Adult↗

PubMed1999

Relation between hemoglobin discordance and adverse outcome in monochorionic twins.

BACKGROUND: The effects of discrepancies in the birth weight and hemoglobin concentration ([Hb]) at the birth on infant outcome have not been fully investigated in monochorionic (MC) and dichorionic (DC) twins. METHODS: A retrospective study of 95 twin pregnancies. All 190 neonates (68 MC twins and 122 DC twins) were admitted to the neonatal intensive care unit, and the [Hb] was determined soon after birth. The [Hb] discordance represents the [Hb] of the smaller twin expressed as a percentage of the [Hb] of the larger twin. Infants were followed-up until 1 year of corrected age and their psychomotor development was evaluated between 12 and 18 months. RESULTS: One DC infant died by 1 year of age. Twelve MC infants and eight DC infants had disabilities by 1.5 year of age. In the MC group, 11 infants (28%) of 20 pairs with an intertwin [Hb] discordance >100 had disabilities compared with one (3.6%) of 14 pairs with an [Hb] discordance < or = 100 (p<0.05). A similar trend was observed in the DC group, but the difference was not significant. The incidence of disabled infants increased as the intertwin birth weight discordance increased in MC twins. CONCLUSIONS: An adverse outcome at 1 year of age in MC twins was associated with a greater birth weight discordance and an [Hb] disordance that indicated polycythemia in the smaller twin.

Adult↗

PubMed1999

Effects of placental chorionicity on outcome in twin pregnancies. A cohort study.

OBJECTIVE: To examine the effects of the chorionicity of the placenta on infant outcome at 1 year of age in twin pregnancies. STUDY DESIGN: Cohort study and retrospective review of the medical records of 44 monochorionic (MC) and 164 dichorionic (DC) twin gestations that had been followed at our institution since < 20 weeks' gestation. Physical and neurologic status was assessed at 1 year of corrected age in infants born to these 208 women. RESULTS: Adverse infant outcomes, such as death, cerebral palsy and mental retardation, occurred in 9 (10%) of 88 MC infants (4 deaths and 5 disabled infants) as compared with 12 (3.7%) of 328 DC infants (6 deaths and 6 disabled infants) (P < .05). Although delivery occurred one week earlier in MC than in DC twins (34.7 +/- 2.8 vs. 35.7 +/- 2.3 weeks, P < .01), there was no significant difference in gestational age at birth or birth weight between the 9 MC and 12 DC infants with adverse outcomes. A presumptive antenatal diagnosis of twin-twin transfusion syndrome (TTTS) was made in 14 (32%) of the 44 MC twin gestations. TTTS was considered to be responsible for adverse outcome in 7 MC infants. All 9 MC infants with adverse outcomes and 4 (33%) of 12 DC infants with adverse outcomes belonged to pairs that had weight discordance > or = 25% (P < .01). CONCLUSION: MC twins had an increased risk of adverse outcomes as compared with DC twins, mainly because of TTTS. In both MC and DC twins, a birth weight discordance > or = 25% was associated with adverse infant outcomes. The number of infants with disabilities at 1 year of age was equal to the number of deaths.

Adult↗

PubMed1999

Gestational age-specific normal birth weight for Japanese twins. Risk of early neonatal death in small-for-gestational-age and large-for-gestational-age twins.

OBJECTIVE: To construct nomograms for birth weight in Japanese twins and to investigate the risk of early neonatal death (death within seven days of birth) in small-for-gestational-age (SGA) and large-for-gestational-age (LGA) twins as compared with appropriate-for-gestational-age (AGA) twins. STUDY DESIGN: Of 89,253 infants born at > or = 24 weeks of gestation to women with multifetal pregnancies (96% twins) between 1989 and 1993 in Japan, 1,804 were stillborn, and 891 died within seven days of birth (early neonatal death [END] group). The remaining 86,558 infants were defined as the normal group. We constructed growth curves for the normal and END groups and compared the incidence of early neonatal death among the SGA, AGA and LGA infants. RESULTS: Birth weights in the END group were similar to those in the normal group until 33 weeks of gestation, but was lower than the birth weights of the normal group after 33 weeks. Both SGA and LGA infants had an increased risk of death within 7 days of birth as compared with AGA infants throughout gestation. CONCLUSION: Both SGA and LGA twins were at increased risk of death as compared with AGA twins. We recommend the use of birth weight nomograms in the management of twin pregnancies.

Birth Weight↗

PubMed1999

[The enhancement of formalin induced agitation behavior by intrathecal administration of prostaglandin E1].

The spinal action of pro-inflammatory agent, prostaglandin E1 (PGE1) was investigated in rats, using formalin test. Sprague-Dawley rats were implanted with chronic intrathecal catheters. PGE1 0.25 microgram or 2.5 micrograms injected intrathecally. Ten minutes later, 5% formalin 50 microliters was injected to the dorsum of one hindpaw. For the time-response analysis, the total number of flinches were counted and expressed as responses per minute for each rat. For the dose response analysis, the cumulative responses per minute over the first 5 min (phase 1) and the interval 10-60 min (phase 2) following the formalin injection were calculated for each rat. PGE1 2.5 micrograms produced a significant increase of flinching in both phase 1 and phase 2. Dose dependent increase of flinching was seen only in the phase 2. Touch evoked allodynia was observed after the injection of PGE1 2.5 micrograms, which lasted about 50 minutes. The enhanced flinches induced by intrathecal PGE1 were antagonized by the coadministration of MK-801, hemoglobin or methylene blue. Allodynia was antagonized only by coadministration of methylene blue. These results indicate that hyperalgesia induced by spinal PGE1 in both phase 1 and phase 2 of the formalin test involves an increased release of glutamate and the activation of NMDA receptor in the spinal cord. The mechanism of allodynia observed in the rats given high dose of PGE1 differs from that of hyperalgesia.

Alprostadil↗

PubMed1999

[Anuria due to bilateral renal artery spasm during hysterectomy and oophorectomy].

A decrease in urinary volume during surgery is often encountered. Usually it can be treated with intravenous fluid or diuretics. We here report a rare case of intraoperative anuria in which renal blood flow ceased totally. The patient was 36 year old female (166 cm 50 kg), who was admitted for a investigations of long-term severe hypertension of unknown origin. Radiographic examination showed no adrenal tumor but a right ovarian cyst was found and suspected to be malignant, for which oophorectomy was indicated. After epidural catheterization, general anesthesia was induced by intravenous propofol and vecuronium, and maintained with epidural lidocaine and the inhalation of isoflurane and nitrous oxide mixed with oxygen. During surgery, urinary outflow decreased gradually leading to total anuria, which was resistant to intravenous fluid and furosemide. Intraoperative pyelography was performed and both kidneys and urinary tracts were not visualized. After the surgery, when the patient returned to the ward, urine began to flow. Postoperative pathological examination of the removed ovary showed a presence of renin excreting tumor cells. The anuria was considered to be the result of transient spastic obstruction of bilateral renal arteries, presumably in response to a high level of plasma renin.

Adult↗

PubMed1999

[The effect of olprinone administered after cardio-pulmonary bypass during open heart surgery, evaluated by its plasma concentrations and hemodynamic changes].

Plasma concentrations and hemodynamic effects of olprinone were evaluated in seventeen patients undergoing open heart surgery. The patients were randomized into the bolus group (15 micrograms.kg-1 bolus dose +0.1 microgram.kg-1.min-1 infusion, n = 9) and the non-bolus group (0.1 microgram.kg-1.min-1 infusion, n = 8). Plasma concentrations and hemodynamic variables were measured before CPB (cardiopulmonary bypass; baseline), 5, 60 min after weaning from CPB, and 3, 6 hours after the end of surgery. Plasma concentrations in the non-bolus group were significantly lower than those of bolus group at any point except for 3 hours after the end of surgery. In the bolus group, increases in the cardiac index and stroke volume index were significantly higher compared with the non-bolus group. From these results we conclude that olprinone given in bolus (15 micrograms.kg-1) followed by continuous infusion (0.1 microgram.kg-1.min-1) is efficacious and safe during weaning from CPB.

Aged↗

PubMed1999

Meconium-stained amniotic fluid activates polymorphonuclear leukocytes ultrastructural and enzyme-cytochemical evidence.

The purpose of the present study was to demonstrate morphological evidence that meconium-stained amniotic fluid activates polymorphonuclear leukocytes. We used Boyden chamber techniques to determine the chemotactic activity of meconium-stained amniotic fluid for leukocytes, and ultrastructural enzyme-cytochemistry for peroxidase and alkaline phosphatase to characterize the leukocyte features induced by contact with meconium-stained amniotic fluid. Amniotic fluid with meconium staining enhanced migration of leukocytes. These leukocytes exhibited more numerous cytoplasmic processes and more prominent phagosomes compared to peripheral blood leukocytes. Peroxidase and alkaline phosphatase activity were evident on the phagosomal membranes. Our results indicate that meconium-stained amniotic fluid activates or stimulates polymorphonuclear leukocytes. Meconium-stained amniotic fluid induced leukocyte activation might play important roles in the pathophysiology of initiation of term labor or of the meconium aspiration syndrome.

Alkaline Phosphatase↗

PubMed1999

Enzyme-cytochemically detectable NADPH-diaphorase activity is present in the endoplasmic reticulum and nuclear envelope of the syncytiotrophoblast of the human placenta.

We investigated the subcellular localization of nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) activity, a histo- and cyto-chemical marker of nitric oxide synthase, in human placental trophoblast obtained from women with normal term pregnancies. Tetrazolium salt BSPT was used as the capturing agent. Precipitates of BSPT-formazan indicative of NADPH-d reaction were observed on the membranes of endoplasmic reticulum and nuclear envelope of syncytiotrophoblasts. Our results indicate these two intracytoplasmic organellae are the sites of nitric oxide generation in the syncytiotrophoblasts of normal term human placenta.

Benzothiazoles↗

PubMed1998

A recurrent nonrandom translocation (3;7)(q27;p12) associated with BCL-6 gene rearrangement in B-cell diffuse large cell lymphoma.

Two cases of B-cell diffuse large cell lymphoma associated with the t(3;7)(q27;p12) and BCL-6 rearrangement are described. Cytogenetic studies revealed [case 1] 47,XY,t(3;7)(q27;p12),+12 and [case 2] 45,X,-Y,t(3;7)(q27;p12),del(6)(q21q25),+16,-21. The translocation of each case had a non-random chromosomal change involving a 3q27 locus associated with BCL-6 gene rearrangement identified by Southern blot analysis. Both cases involved multiple lymph nodes and extranodal regions, such as stomach and peritoneal cavity in case 1, extranodal retroperitoneal space, subcutis, probable liver, and colon in case 2. Chemotherapy provided only short survival after onset: 17 and 16 months, respectively. Altered expression of adhesion molecules CD44, CD54 (case 1) and CD11a and CD18 (case 2) may help to explain the poor outcome of these patients.

Aged↗

PubMed1998

Normal developing rat brain expresses a platelet-derived growth factor B chain (c-sis) mRNA truncated at the 5' end.

The 5' untranslated sequence (5' UTS) of platelet-derived growth factor B (PDGF-B/c-sis) mRNA is highly preserved through evolution, and inhibits translation of downstream coding sequences. In this study, using Northern analysis we identified two PDGF-B/c-sis mRNAs (3.5 kb and 2.6 kb) expressed in normal developing rat brain. In contrast to the constitutive expression of 3.5 kb mRNA, the expression of 2.6 kb mRNA increased markedly in accordance with those stages of brain development at which we had previously demonstrated an increased immunoreactivity for PDGF-B/c-SIS in neurons (Sasahara et al., 1992). By PCR cloning and the RNase protection assay, we determined the complete sequence of rat PDGF-B/c-sis, and found that the 2.6 kb transcript was a form of the 3.5 kb message truncated at the 5' end, and that the predominant 2.6 kb mRNA commenced 15 nt upstream of the signal peptide. Accordingly, it is suggested that the truncation of 5' UTS contributes to the expression of PDGF-B/c-SIS protein in the CNS. Lack of translational inhibitory 5' UTS of PDGF-B/c-sis transcript and resultant efficient protein translation have been reported in only a few transformed cells and cultured umbilical vein endothelial cells. We have extended this knowledge to the developing rat brain, and suggest that a similar mechanism could operate widely in non-transformed tissue in vivo.

Animals↗

PubMed1998

Pelvic lymphocysts following retroperitoneal lymphadenectomy: retroperitoneal partial "no-closure" for ovarian and endometrial cancers.

BACKGROUND AND OBJECTIVES: Pelvic lymphocysts have been reported mainly following pelvic lymphadenectomy for cervical cancer. We attempted to assess whether retroperitoneal partial "no-closure" reduces the incidence of lymphocyst formation following retroperitoneal lymphadenectomy. METHODS: Sixty-one patients with ovarian cancer or endometrial cancer who underwent retroperitoneal lymph node resection were assigned at random to a retroperitoneal partial "no-closure" group or a "closure" group. The incidence of lymphocysts in the two groups as determined using ultrasonography was compared. RESULTS: Lymphocysts appeared in 23/61 patients (38%) in total. In the "closure" group, the incidence was 52% (16/31), but in the "no-closure" group it was only 23% (7/30); the incidence in the "no-closure" group was significantly lower (P < 0.05). The incidence of postoperative fever was 17% (5/30) in the "no-closure" group, which was lower than that in the "closure" group (42%, 13/31), but not significantly so (P < 0.1). No patients in the "no-closure" group required surgical procedures such as needle aspiration or cyst drainage. CONCLUSIONS: Retroperitoneal partial "no-closure" appears to be a useful procedure for reducing the incidence of pelvic lymphocysts associated with retroperitoneal lymphadenectomy.

Aged↗

PubMed1998

Macrophage colony-stimulating factor as a marker for malignant germ cell tumors of the ovary.

We assessed the usefulness of macrophage colony-stimulating factor (M-CSF) as a serum marker for malignant germ cell tumors of the ovary. Serum levels of M-CSF were measured in 49 patients with malignant germ cell tumors and in 64 patients with mature benign cystic teratoma by an enzyme-linked immunosorbent assay. CA125 was measured by radioimmunoassay. The serum level of M-CSF was above normal (>1056 U/ml) in 44 (90%) of 49 patients with malignant germ cell tumors; the CA125 level was above the cutoff value (35 U/ml) in 34 patients (69%) (P < 0.05). The serum level of M-CSF was elevated in 20 (87%) of 23 patients with stage I disease and in all 16 patients with dysgerminoma. Only 7 (11%) of 64 patients with mature benign cystic teratoma had elevated levels of M-CSF. These results suggest that M-CSF is highly sensitive and specific for malignant germ cell tumors of the ovary, especially for dysgerminoma.

Biomarkers, Tumor↗

PubMed1998

Rare case of small-cell carcinoma arising from the endometrium with paraneoplastic retinopathy.

We present the fourth known case of endometrial carcinoma, and the second case of endometrial small-cell carcinoma, to be associated with paraneoplastic retinopathy. Initial symptoms were decreased visual acuity and a narrowing of the visual field. Endometrial carcinoma was diagnosed several months later. An antibody to 34-kDa bovine retinal antigen was detected in the patient's serum. Thus, autoimmunity was suspected as the cause of the retinopathy. In patients with endometrial carcinoma with visual disturbance of unknown cause, paraneoplastic retinopathy should be suspected.

Carcinoma, Small Cell↗