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Biomedical subjects

R Hashimoto

Publications and source records attributed to R Hashimoto.

At least 127 records · Page 7Linked to original sources
PubMed1991

Naloxone injected into the preoptic region has hypophysiotropic and seizurogenic actions in rats.

The effects of microinjection of naloxone, an opiate receptor antagonist, into the medial preoptic area (MPO) and diagonal band of Broca (DBB) on luteinizing hormone (LH) and prolactin (PRL) secretion were examined in the intact male rat and female rat in diestrus 1. In both the male and female rats, the injection of 50 micrograms naloxone at 1300 h produced an acute, two- to three-fold increase in serum LH, attaining the peak at 20 min. The PRL concentration in the female 20 min-2 h after the injection was significantly lower than in the saline-injected rat. In the male rat, naloxone caused a decrease in the PRL concentration in the late afternoon when a small rise occurred in the saline-injected rat, although it caused no immediate changes. In addition to these hypophysiotropic effects, naloxone injected in the MPO and DBB unexpectedly had seizurogenic actions. More than 40% of the animals of both sexes given an injection of naloxone had behavioral seizures, which began after about 20 min and were repeated intermittently at 15-20 min intervals through the sampling period of 6 h. In the LH and PRL response to naloxone, there was no significant difference between animals with and without seizure response in both sexes. The results suggest that in the preoptic opioid system there is no difference according to sex in the control of LH, and only a small one, if any, in the control of PRL. Further, on the basis of previous reports, there is a GABAergic system in the preoptic region, that is antagonized by naloxone and causes the activation of cortical neuronal activity.

Animals↗
PubMed1991

[Nonocclusive intestinal necrosis after the successful veno-arterial bypass].

A 52-year-old male suffered from acute viral myocarditis with severe cardiogenic shock. On his admission, he underwent the inotropic and IABP supports, and subsequently was treated effectively by V-A bypass, which was continued for 35 hours. But he died in the period of 69 hours after V-A bypass from extended bowel necrosis and septic shock. The small and large intestinal mucosal necrosis, hemorrhagic hepatic necrosis and acute tubular necrosis were confirmed at necropsy. It is well known that the nonocclusive mesenteric vascular spasm is concerned strongly in their pathogenesis, after prolonged severe cardiogenic shock.

Acute Disease↗
PubMed1990

Proclotting enzyme from horseshoe crab hemocytes. cDNA cloning, disulfide locations, and subcellular localization.

Proclotting enzyme is an intracellular serine protease zymogen closely associated with an endotoxin-sensitive hemolymph coagulation system in limulus. Its active form, clotting enzyme, catalyzes conversion of coagulogen to insoluble coagulin gel. We present here the cDNA and amino acid sequences, disulfide locations, and subcellular localization of proclotting enzyme. The isolated cDNA for proclotting enzyme consists of 1,501 base pairs. The open reading frame of 1,125 base pairs encodes a sequence comprising 29 amino acid residues of prepro-sequence and 346 residues of the mature protein with a molecular mass of 38,194 Da. Three potential glycosylation sites for N-linked carbohydrate chains were confirmed to be glycosylated. Moreover, the zymogen contains six O-linked carbohydrate chains in the amino-terminal light chain generated after activation. The cleavage site that accompanies activation catalyzed by trypsin-like active factor B, proved to be an Arg-Ile bond. The resulting carboxyl-terminal heavy chain is composed of a typical serine protease domain, with a sequence similar to that of human coagulation factor XIa (34.5%) or factor Xa (34.1%). The light chain has a unique disulfide-knotted domain which shows no significant homology with any other known proteins. Thus, this proclotting enzyme has a mammalian serine protease domain and a structural domain not heretofore identified in coagulation and complement factors. Immunohistochemical studies showed that the proclotting enzyme is localized in large granules of hemocytes.

Amino Acid Sequence↗
PubMed1990

Dopaminergic cells align along radial glia in the developing mesencephalon of the rat.

Studies were performed to examine the relation of dopaminergic cells and radial glia in the developing mesencephalon of the rat at ages E12-E20. Dopaminergic cells were immunolabelled with an antiserum which recognizes tyrosine hydroxylase, and radial glia were immunolabelled with a monoclonal antibody which recognizes vimentin. The vimentin-immunoreactive fibres of radial glia were noted at E12. At E12, and more clearly at later time points, the radial glia extended from the aqueduct to the pial surface, and this pattern persisted throughout the prenatal period. Tyrosine hydroxylase-immunoreactive cells were located along the ventral surface of the mesencephalon at age E13. At age E15, E16, and E18 the tyrosine hydroxylase-immunoreactive cells were present from the aqueduct to the ventral pial surface of the mesencephalon and were aligned along radial glia. Our study suggests that radial glia provide paths for migration of dopaminergic cells in the mantle layer from E15 to E18 of the developing mesencephalon. It also suggests that some dopaminergic cells between E15 and E18 may express tyrosine hydroxylase during their migration through the mantle layer and prior to reaching the location they occupy in the adult brain.

Aging↗
PubMed1990

Analysis of the morphology and structure of crowns in a young sugi (Cryptomeria japonica) stand.

Crown form, vertical changes in branch inclination and vertical distribution of foliage density in a young sugi (Crytomeria japonica D. Don) stand were analyzed using allometric equations. Tall trees had deeper crowns than short trees, whereas the crown diameters of both tall and short trees were similar. Apical roundness was more pronounced in the lower-story trees, which were characterized by umbrella-shaped crowns. The vertical distribution of foliage density was approximated by a nearly symmetrical curve. Tall trees had higher spatial densities of foliage than short trees. Branch inclination also varied significantly with tree height. The middle-story trees had the largest branch inclinations and the lower-story trees had the smallest branch inclinations. Even in young uniform stands, crown morphology and structure were modified in response to the light environment.

Journal Article↗
PubMed1990

Development of the innervation pattern in the upper limb of staged human embryos.

The upper limb nerves of 8 human embryos (Carnegie stages 13-21) were studied by reconstruction. In stage 13, upper limb nerves (C5-T1) extended from the spinal cord. In stage 14, these nerves united to form the nascent brachial plexus. In stages 16 and 17, the median nerve, the radial nerve and the ulnar nerve entered into the hand plate. In stages 20 and 21, the upper limb nerves were observed in an orientation and arrangement similar to those in the adult.

Arm↗
PubMed1990

LH and PRL secretion in ovariectomized spontaneously hypertensive rats.

The pulsatile patterns of LH and PRL secretion, and effects of stress on these patterns were examined in ovariectomized normotensive Wistar, spontaneously hypertensive, and genetically matched normotensive Wistar Kyoto rats. Judged by the overall mean of PRL concentrations, PRL levels in spontaneously hypertensive rats were not different from those in Wistar Kyoto rats, but the pulse amplitudes as well as the overall mean concentrations were significantly greater in both Wistar Kyoto and spontaneously hypertensive rats than in Wistar rats. Increases in PRL release during immobilization stress in spontaneously hypertensive rats occurred earlier than in Wistar rats, but the peak levels were not different between the two animal groups, though significantly lower in Wistar Kyoto rats than in Wistar rats. Overall mean of LH concentrations was higher, but pulse amplitude was smaller in spontaneously hypertensive rats than in Wistar Kyoto rats, and in both groups significantly smaller than in Wistar rats. The decrease in LH release owing to stress was similar in all animal groups. A significant association between LH and PRL peaks was evident in all animals, although the rate of association was lowest in Wistar Kyoto rats. In conclusion, the central nervous system mechanisms for both LH and PRL secretion differ markedly in both spontaneously hypertensive and Wistar Kyoto rats from those in Wistar rats, and no specific difference was found in spontaneously hypertensive rats compared with Wistar Kyoto and Wistar rats as controls.

Animals↗
PubMed1990

Esophageal cancer complicated by acute myelofibrosis--report of an autopsy case.

An autopsy case of esophageal cancer complicated by myelofibrosis was studied. A 62-year-old Japanese patient with esophageal cancer, received surgical treatment and then splenectomy. The resected spleen was normal in appearance. Five months later he received radiation therapy for the cancer. After the therapy, his blood profile revealed thrombocytopenia and leukoerythroblastosis, and the bone marrow punctures were dry tap. He died of disseminated fungal infections at eleven months after the first operation. An autopsy of the patient revealed a striking increase in the megakaryocytes and a moderate increase in the reticulin fibers in the bone marrow. Myeloid metaplasia was noted in the lymph nodes, kidneys, and other organs and tissues, although the lymph nodes were not grossly swollen. These findings suggest esophageal cancer complicated by acute myelofibrosis. This it the first case report on esophageal cancer complicated by acute myelofibrosis.

Acute Disease↗
PubMed1990

Effects of thyroid hormone and actinomycin D on phosphate uptake of brush-border membrane vesicles from kidney of rachitic rats.

It is generally accepted that 3,5,3'-triiodothyronine (T3) is responsible for most of the known physiological actions of thyroid hormone. Our new rachitogenic diets, deficient in both vitamin D and iodine and low in phosphorus (1.13% calcium and 0.14% phosphorus), induced typical rachitic changes in rats. To know the possible role of T3 on bone and phosphate (Pi) metabolism and its related biochemical and molecular mechanism, weanling male Wistar rats were fed this diet for 28 days, and then treated with 6 micrograms/100g BW of T3 and/or 60 micrograms/100g BW of actinomycin D intraperitoneally. After 2 hours of treatment, renal brush-border membrane vesicles (BBMV) were prepared according to the calcium precipitation method, and their Na(+)-dependent Pi uptake was analyzed by Lineweaver-Burk plots. Km value was not significantly altered by all these treatments. In contrast, Vmax value as a Pi uptake index was significantly increased in T3-treated rats compared with rachitic control. This increase was evident as less as 2 hr after T3 administration, so it was assumed that T3 stimulated the Pi uptake not by mediation of the de novo protein synthesis. However this increase was suppressed by administration of actinomycin D, and then this result suggests that the antirachitic effect of T3 is mediated by somehow de novo protein synthesis. After all, T3 acting as an antirachitic agent, the most likely possibility is that T3 provides favorable conditions for mineralization of bone by improving Pi transport in various types of cells, even under rachitogenic condition, at least of hypophosphatemic type, and correction of phosphate metabolism may be the most essential prerequisite for cure of this type of rickets.

Animals↗
PubMed1990

IgA myeloma complicated by fractures of the bones and hyperviscosity syndrome--report of an autopsied case.

A case of IgA (kappa type) myeloma complicated by fractures of the bones and hyperviscosity syndrome is presented. A 56-year-old woman who had been followed as an outpatient with diabetes mellitus for about 16 years, developed multiple myeloma. She also showed symptoms and signs of hyperviscosity syndrome; hemorrhagic diathesis, blurred vision and episodes of transient ischemic attacks of the brain, and fractures of the bones by small powers of trauma. At autopsy, almost all bones showed infiltration of multiple myeloma of IgA-kappa type and severe osteoporosis accompanied with proliferation of osteoclasts. The association of IgA myeloma with hyperviscosity syndrome and/or bone destruction was discussed. The "serum hyperviscosity syndrome" has been described clinically as the triad of bleeding, visual signs and symptoms, and neurologic manifestations. And this syndrome has been associated frequently with macroglobulinemia of Waldenström, occasionally with immunoglobulin (Ig) G myeloma, rarely with IgA myeloma, and with other dysproteinemia. Myeloma is also characterized by extensive bone destruction and is accompanied by susceptibility to fracture, although Waldenström's macroglobulinemia, acute leukemia or chronic leukemia are rarely associated with bone resorption. The present report describes a patient with IgA myeloma complicated by hyperviscosity syndrome and multiple bone fractures.

Blood Viscosity↗
PubMed1989

Puberty and ovulatory release of gonadotropins in spontaneously hypertensive rats.

The age at vaginal opening, estrous cyclicity, serum levels of luteinizing hormone (LH), follicle stimulating hormone (FSH) and prolactin (PRL) on the day of proestrus, and number of ova and ovarian weight as measured on the day of estrus in spontaneously hypertensive (SH) and genetically matched normotensive Wistar Kyoto (WKY) female rats were compared. In SH rats, there was a significant delay in the vaginal opening, but the regular 4-day estrous cycle followed afterwards. No significant changes were observed in the afternoon increase in serum LH, FSH and PRL on the day of proestrus in SH and WKY rats, although the basal levels of LH and PRL in the morning (11:00 h) were lower in SH rats than in WKY rats. The mean number of ova in SH rats was also less than in WKY rats, whereas the ovarian relative weight was similar in both species of rats. It can be said that SH rats undergo certain, but not critical, endocrine and/or neuroendocrine changes related to reproduction.

Animals↗
PubMed1989

Time-dependent effects of intrahypothalamic injection of vasoactive intestinal peptide on spontaneous motor activity in rats.

In male Wistar rats, microinjection cannulae were stereotaxically implanted in the ventromedial and paraventricular hypothalamic nuclei. After control recordings of spontaneous motor activity for 4-6 days, vasoactive intestinal peptide (VIP) was injected in a dose of 1.0 microgram and a volume of 2.0 microliters into these nuclei at 1100 or 1900 h, and the activity during the 3-h period following was compared with that on the control days in individual animals. VIP injection produced an increase when injected at 1100 h, and a decrease when injected at 1900 h. Thus, a time-dependent fluctuation in the VIP effect on the hypothalamic neuronal activity was suggested.

Animals↗
PubMed1989

Complicated central effects of endothelin on blood pressure in rats.

The role of endothelin (ENT) in the control of systemic blood pressure (BP) was examined in conscious rats. Intracerebroventricular (i.c.v.) administration of ENT (0.002 or 0.2 micrograms, i.e., 0.78 or 78 pmol/2 microliters 0.9% saline) to conscious rats had complicated effects on BP. A significant fall in BP occurred in the initial 2-4 min after administration; and then after recovery toward the control level, BP decreased again within 17 min, following which a constant rise in BP occurred. In addition to the changes in BP, 3 of 9 rats which received 0.2 micrograms lapsed into severe barrel rotation-like behavior only to die 6-8 min after i.c.v. injection. It was therefore assumed that ENT had central effects on BP regulation and motor activity.

Animals↗
PubMed1989

[A T-cell type non-Hodgkin's lymphoma with a near-triploid karyotype].

A 16 year-old boy of non-Hodgkin's lymphoma (NHL) was reported. Although Hodgkin's disease was suspected by the presence of Reed-Sternberg-like cells and lacunar cells histologically, a diagnosis of NHL was made because of atypism and monoclonality of the background's cells as well as the morphology of invasive cells in the bone marrow. The tumor cells expressed, CD2, CD3, CD4, CD5 and CD7 antigens, which corresponded to the phenotype of helper-inducer T-lymphocytes. In the analysis of their karyotypes, 16 out of 24 cells revealed normal karyotype, while all the rest showed near-triploidy. Common abnormality was identified as trisomies of No. 1, 3, 5, 16, 21 chromosomes, tetrasomies of No. 10, 19, 20 chromosomes, and 4q+, 7q+, 14p+. Multimodal chemotherapy was successful to induce the patient promptly into complete remission. He has been free from the disease for approximately 12 months. Thus far, triploid clones in hematopoietic malignancies have rarely been described. More importantly, the appearance of them in pediatric lymphoid neoplasms has not yet been reported.

Adolescent↗
PubMed1989

Nuclear binding sites for reverse triiodothyronine in human placenta.

It has been generally believed that reverse triiodothyronine (reverse T3, rT3) is biologically inactive. Nevertheless the serum rT3 level is very high in fetal life, when the serum calcium level is higher than in the maternal. For this hypercalcemia in fetal life, there is no convincing evidence that any major calcium regulating hormone is responsible. And the assumption that rT3 may be concerned in active transport of calcium at placenta could be suggested. In this study nuclear protein was isolated from human placenta by extraction with 0.4M KCl buffer and binding studies utilizing radioactive rT3 were carried out. Scatchard analysis presented a curvilinear pattern, suggesting two classes of receptors: One with a association constant (Ka) of 1.14 X 10(8) M-1 and a limited capacity (Bmax) of 32.0 X 10(-15) mol/100 micrograms DNA and the other with Ka = 4.34 X 10(6) and Bmax = 454 X 10(-15). Its relative affinities for several thyroid hormone analogues were calculated. If the affinity for rT3 was assigned l, that for triiodothyronine would be 1/40, thyroxine: 1/63, Triiodothyroacetic acid: 1/18. Sulfhydryl agents affecting these binding characteristics were also studied. The Ka was not substantially changed but the Bmax was notably decreased by dithiothreitol (43%) and 2-mercaptoethanol (26%). In liver nuclei, the binding characteristics of rT3 receptor were analyzed for comparison. In this case only a single class of low affinity-high capacity rT3 binding site with a Ka of 6.69 X 10(6) was detected, a finding which was apparently different from those in placenta.(ABSTRACT TRUNCATED AT 250 WORDS)

Binding Sites↗
PubMed1989

[The usefulness of two-dimensional transesophageal echocardiography in follow-up studies of dissecting aortic aneurysm].

Two-dimensional transesophageal echocardiography (2D-TEE) facilitates clear imaging of the thoracic aorta, and we have already reported the diagnostic value of this procedure for detecting dissecting aortic aneurysm (DAA). Recently, we performed preoperative and postoperative 2D-TEE in nine surgically treated patients with DAA (Debakey type I: 2 cases, type II: 1 case, type IIIa: 2 cases, type IIIb: 4 cases), and repeated 2D-TEE in six medically treated patients (DeBakey type IIIa: 2 cases, type IIIb: 4 cases), and the usefulness of 2D-TEE in the follow-up study of DAA was evaluated. Two types of ultrasound probe (radial scan type, and sector type with a color-Doppler system) were used in this study. Of the surgically treated patients, four of nine cases in which the initial tears were excised or repaired showed neither leakage nor pseudoaneurysm at the site of graft insertion. Other surgically treated patients showed residual intimal tears and continued to harbor patent false lumen. One patient with type I dissection demonstrated localized saccular aneurysm in the proximal arch of the aorta, but no evidence of aortic regurgitation. Of the six medically treated patients, further extension of the initial dissection was observed in one of the two type IIIa cases. False lumen narrowing was recognizable in three of the four type IIIb patients, and complete obliteration of false lumen was observed at necropsy in one of these three cases. Double-channeled aorta was seen in another case of type IIIb dissection.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗