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Biomedical subjects

I Nagata

Publications and source records attributed to I Nagata.

At least 271 records · Page 15Linked to original sources
PubMed1987

Parathyroid hormone-induced lipolysis in human adipose tissue.

Relative lipolytic activity of human parathyroid hormone-(1-34) (hPTH-(1-34], hPTH-(3-34), desamino-Ser1-hPTH-(1-34), and rat PTH-(1-34) was compared in human subcutaneous adipose tissues in vitro. Human PTH-(1-34), rat PTH-(1-34), and desamino-Ser1-hPTH-(1-34) stimulated in vitro lipolysis significantly above basal level at the concentration of 10(-6) M. Average increments of lipolytic rate were 2.39, 1.82, and 0.87 mumol/g per 2 hr, respectively, being significantly different among the three groups. On the other hand, hPTH-(3-34)-induced lipolytic rate was 0.83 +/- 0.18 mumol/g per 2 hr, not significantly different from the basal level (0.71 +/- 0.20 mumol/g per 2 hr). The effect of hPTH-(3-34) on glycerol release stimulated by hPTH-(1-34), isoproterenol, or forskolin was subsequently investigated. Human PTH-(3-34) produced a dose-dependent inhibition of hPTH-(1-34)-stimulated lipolysis. In contrast, isoproterenol- and forskolin-induced lipolytic rates were not influenced by hPTH-(3-34). The effect of propranolol on hPTH-(1-34)- or isoproterenol-induced lipolysis was also studied. Propranolol dose-dependently inhibited isoproterenol-induced lipolysis but had no effect on lipolysis stimulated by hPTH-(1-34). These results suggest that the amino acids at positions 1 (serine) and 2 (valine) of PTH are critical for the stimulation of lipolysis in human adipose tissue. Human PTH-(1-34) causes lipolysis after binding to receptors distinct from beta-adrenergic receptors of fat cells and possibly hPTH-(3-34) inhibits hPTH-(1-34)-stimulated lipolysis by competing at the level of PTH receptor.

Adipose Tissue↗
PubMed1987

[Application of spinal dynamic computed tomography in the diagnosis of spinal cord arteriovenous malformations].

Seventeen cases of spinal cord arteriovenous malformation (AVM) were evaluated by use of spinal dynamic computed tomography (CT). In the intravenous injection method, contrast medium was injected bolusly into the median cubital vein. In the intraarterial injection method, contrast medium was injected slowly into the feeding artery. In both methods, lesions were demonstrated in all cases. Three-dimensional localization of the lesions were more clearly demonstrated in the intraarterial injection method. Intravenous injection method was useful in the postoperative follow-up study due to its noninvasiveness.

Adolescent↗
PubMed1987

[Intraoperative liquid embolization of an arteriovenous malformation in the basal ganglia and thalamic region].

Total three patients with arteriovenous malformation (AVM) in basal ganglia or thalamic region were treated by intraoperative liquid embolizations. These procedures were decided because of repeated hemorrhagic episodes. In the case with AVM in the head of the caudate nucleus which was fed by several anterior perforating arteries originated from anterior cerebral artery (A1 portion) and middle cerebral artery (M1 portion), frontotemporal craniotomy was performed. After the microsurgical dissection of these feeders, one of the feeders lenticulostriate artery, was cannulated with a small-caliber polyethylene catheter, 0.6 mm in outer diameter and 0.3 mm in inner diameter. A small amount of isobutyl 2-cyanoacrylate (IBCA) was injected through the catheter. Same procedure was carried out one month later. Postoperative angiograms revealed about 90% loss of AVM. In two cases with AVM which involved almost entire thalamus, subtemporal craniotomy was done. Feeding vessels which originated from posterior communicating artery and posterior cerebral artery (PCA) were carefully dissected under the operative microscope and one of them was prepared for cannulation with small catheter. When the small amount of IBCA was injected, proximal PCA and internal carotid artery were temporarily occluded. In both cases intraoperative embolization was carried out twice. Postoperative angiograms revealed that the size of AVM was decreased to 20% in one and 40% in the other. Although temporary postoperative deterioration of neurological deficits such as hemiparesis and visual disturbance was slightly noted in all cases, no hemorrhagic episode was experienced for 6 months, 1.5 and 2 years in each after embolization.

Adult↗
PubMed1986

Conversion of embryonic to adult form of the neural cell adhesion molecule (N-CAM) does not correlate with pre- and postmigratory states of mouse cerebellar granule neurons.

The migration of postmitotic granule neurons from the external to the internal granular layer along the radial processes of Bergmann glia is an outstanding event in the development of the early postnatal mouse cerebellar cortex. It has been hypothesized that the conversion of the embryonic to the adult form of the neural cell adhesion molecule (N-CAM) is important for this migration since this conversion coincides with the time of migration [2, 10]. To investigate this issue we have examined the molecular forms of N-CAM by Western blot analysis in tissue obtained from hand-dissected cerebellar layers at several stages of early postnatal development. Here we report that there is no temporal difference between internal and external granular layers in shifting from exclusive expression of the embryonic form of N-CAM at postnatal day 1 to predominance of the adult form at day 17. White matter shows a delay in the conversion to the adult form which is completed only after day 17. We conclude that the transition from embryonic to adult form of N-CAM is not a prerequisite for granule neuron migration.

Animals↗
PubMed1986

Traumatic stenosis of the internal carotid artery in children.

Two cases of stenosis of the internal carotid artery after blunt craniocervical trauma in children are described. Their neurological symptoms developed a few hours after the injury. A superficial temporal artery-middle cerebral artery anastomosis was performed in one, and the other was conservatively treated because of the spontaneous resolution of the stenosis. The pathophysiology and treatment of this clinical entity, especially in children, are discussed.

Accidents, Home↗
PubMed1986

Neuronal influence on antigenic marker profile, cell shape and proliferation of cultured astrocytes obtained by microdissection of distinct layers from the early postnatal mouse cerebellum.

To study the cellular heterogeneity of astrocytes from early postnatal mouse cerebellum in culture, Bergmann glia were enriched by hand-dissection of Purkinje, molecular and external granular layers ('outer' layer) and fibrous astrocytes of white matter and deep cerebellar nuclei ('inner' layer). Both populations of GFA protein and vimentin-positive astrocytes express N-CAM and the L2/HNK-1 epitope, but not tetanus toxin receptors or A2B5 antigen, at levels detectable by indirect immunofluorescence procedures. The two astrocyte populations are thus indistinguishable from each other. Expression of tetanus toxin receptors and A2B5 antigen in these astrocytes can, however, be induced by removal of neurons. The expression of tetanus toxin receptors is again reduced by readdition of purified populations of small cerebellar neurons. Morphology and proliferation of astrocytes from both layers is also dependent on the presence of neurons: removal of neurons leads to an epithelioid, rather than star-shaped morphology and a severalfold increase in proliferation. Readdition of neurons induces astrocytes to return to their star-shaped morphology. Epidermal growth factor increases proliferation in both populations of astrocytes. We conclude that neither antigenic marker profile, morphology nor proliferative responses serve to distinguish between enriched Bergmann glia and enriched fibrous astrocytes.

Animals↗
PubMed1986

Ovulatory disturbances. Causative factors among Japanese student nurses in a dormitory.

The incidence of ovulatory disturbances in student nurses living in a restricted circumstance was evaluated by observing a basal body temperature (BBT) chart recorded for three to nine months by all of the student nurses in our medical college. The students were 18-21 years of age and were all living in a school dormitory. One hundred of the 154 students (64.9%) were anovulators during the school term. However, 40 of the anovulators showed ovulatory cycles with biphasic BBT patterns during their spring and/or summer holidays. The subjects' living conditions were investigated by questionnaire. Age of menarche, sport activity, self-perceived physical and mental work load, and native region did not appear to be related to their ovulatory disturbances. Weight-height-derived indices indicated that the anovulators had a tendency to corpulence as compared to the regular ovulators. Serum luteinizing hormone, follicle stimulating hormone, and prolactin levels of the anovulators were not significantly different from the regular ovulators.

Adolescent↗
PubMed1986

Effect of benzodiazepine derivatives: I. Augmentation of T cell-dependent antibody response by diazepam in mouse spleen cells.

Oral administration of diazepam at doses of 5-10 mg/kg to restraint-stressed mice resulted in almost complete recovery in the stress-induced suppression of the antibody response to sheep red blood cell (SRBC). Moreover, this compound restored the suppression of antibody response to SRBC in cyclophosphamide-treated mice. Diazepam treatment also enhanced the antibody response against SRBC in normal mice only when the animals were immunized with the reduced amount of antigen. It was demonstrated that antigen specific helper T cell activity was promoted by diazepam administration in mice. Addition of diazepam augmented the in vitro anti-SRBC hemolytic plaque-forming cell (PFC) response in mouse splenocytes without altering kinetics of the response. However, the enhancing effect was observed only when the drug was added to the medium at the culture initiation. On the other hand, antibody response to T cell-independent antigens such as trinitrophenylated (TNP)-Ficoll and TNP-lipopolysaccharide were not enhanced by diazepam. Concanavalin A or LPS-induced 3H-thymidine uptake into splenocytes were not stimulated by diazepam. These results suggest that diazepam promotes the antibody response through stimulating helper T cell functions.

Animals↗
PubMed1986

Study of the posterior circulation in moyamoya disease. Part 2: Visual disturbances and surgical treatment.

The involvement of the posterior circulation in moyamoya disease was studied in 178 patients. Forty-three had several types of disturbance such as visual field defect, decreased visual acuity, episodes of blindness, and scintillating scotomata. Most of these symptoms were attributed to occlusive lesions in the posterior circulation. Visual disturbances were seen more often in patients with a juvenile onset than in cases of adult onset. Superficial temporal artery (STA) to middle cerebral artery (MCA) anastomosis and encephalomyosynangiosis (EMS) improved the cerebral perfusion both in the anterior and posterior circulation by redistribution of blood. In most cases, the visual symptoms subsided or were stabilized after STA-MCA anastomosis and EMS. These surgical procedures did not, however, lead to direct revascularization in cases of ischemia in the visual cortex. In five patients with impending blindness, transplantation of the omentum to the occipital lobe led to improved vision.

Adolescent↗
PubMed1986

Localization and kinetic properties of prostaglandin E1 receptor on the plasma membrane of rabbit myometrium in late pregnancy.

The distribution of prostaglandin E1 (PGE1) receptor in various subcellular fractions of pregnant rabbit myometrium was closely related with the distribution of [Na + K]-ATPase, 5'-nucleotidase, and Ca2+-ATPase activities, marker enzymes for plasma membrane, but not with that of NADPH-cytochrome c reductase activity, which is a marker enzyme for endoplasmic reticulum. The specificity of PGE1 receptor was significantly different from those of PGE2 and PGF2 alpha. The PGE1 receptor concentration in the plasma membrane fraction increased significantly from 89.0 to 111.1 fmol/mg protein between the 28th and 30th days of pregnancy. Scatchard analysis of PGE1 receptor revealed a nonlineal plot which indicated the existence of negative cooperativity in a kinetic study.

5'-Nucleotidase↗
PubMed1986

[Studies on the blood constituents of the neonates delivered by the induced delivery of the Defense Medical College method].

For the assessment of the influence of the Defense Medical College planned delivery method upon neonates, the measurement of the blood constituents of the umbilical cord was conducted. Statistically speaking, no marked differences were seen between the neonates delivered by the Defense Medical College Method and neonates delivered naturally. The blood constituents investigated were: Blood cells, activity of various enzymes, other blood constituents and electrolytes.

Adult↗
PubMed1986

[Sacrospinous ligament fixation of vaginal apex for repair operation of uterine prolapse--operative procedure and postoperative outcome evaluated with score system and X-ray subtraction colpography].

To preserve a snug vagina with complete repair, sacrospinous ligament fixation (SLF) to the vaginal apex was applied in operations for uterine prolapse from the April of 1983 to the April of 1984. SLF was added to 11 vaginal hysterectomies with anterior and posterior (A-P) colporrhaphy, 1 Manchester operation and 1 A-P colporrhaphy. SLF was performed at the stage of posterior colporrhaphy in each operation. The postoperative outcome was evaluated with a score system and an X-ray subtraction colpography. The score system describes the grade of vaginal relaxation in each part of the vagina before and after the operation. It showed that the vagina was repaired quite well by the SLF especially in the area of the vaginal apex and posterior wall. The subtraction colpography revealed the side view of the vagina and its movement on straining. It suggested that the SLF was a reasonable procedure for the prevention of recurrence. SLF also proved to have wide application to the repair of uterine prolapse including patients desiring the preservation of childbearing capability and elderly or poor-risk patients.

Adult↗
PubMed1986

Neutral glyceride synthesis from glucose in human adipose tissue: comparison between growing and mature subjects.

Basal and insulin-stimulated neutral glyceride syntheses from glucose were studied in fat cells of different size (fat cell volume, 0.07-0.20, 0.20-0.60, 0.60-1.00, 1.00-1.50 micron3 X 10(6)) obtained from subcutaneous adipose tissues in 20 subjects aged 3 months to 67 years. In 0.07-0.20 or 0.20-0.60 micron3 X 10(6) fat cells, the basal rate of glucose conversion to neutral glyceride was significantly lower in mature (36 to 67 years old) than in growing (0 to 12 years old) subjects. In 0.60-1.00 or 1.00-1.50 micron3 X 10(6) fat cells, however, basal rate was not significantly different between the two groups. The stimulating effect of insulin on conversion of glucose to neutral glyceride was not significantly different from the basal rate in fat cells of each size taken from the mature subjects, whereas in fat cells from growing subjects, it was significantly different from the basal rate in each fat cell size category. These results indicate that when fat cell size is taken into account, not only is the rate of basal glucose conversion to neutral glyceride higher in growing subjects but also its responsiveness to exogenous insulin, and that insulin insensitivity of large fat cells, reported previously, may be influenced by age.

Adipose Tissue↗