PubMed Health⌕ Search

Biomedical subjects

R Hashimoto

Publications and source records attributed to R Hashimoto.

At least 127 records · Page 7Linked to original sources
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↗
PubMed1988

Preoptic injection of VIP, but not of secretin or PHI, inhibits LH and stimulates prolactin secretion in the ovariectomized rat.

The microinjection of vasoactive intestinal peptide (VIP) into the medial preoptic area rapidly inhibited pulsatile luteinizing hormone (LH) secretion within 1 h in ovariectomized rats. A transient but significant increase in prolactin (PRL) secretion occurred after VIP injection coincidentally with the initiation of the inhibition of LH pulses. Preoptic microinjections of secretin or peptide histidine isoleucine amide (PHI) did not have such effects. These results suggest specific actions of VIP, despite its structural similarity to secretin and PHI, on the preoptic mechanisms governing LH and PRL secretion in ovariectomized rats.

Animals↗
PubMed1988

Effects of preoptic injection of glucagon on luteinizing hormone secretion in ovariectomized rats with or without estrogen priming.

Effects of microinjection of glucagon or GIP into the medial preoptic area on luteinizing hormone (LH) and prolactin (PRL) release were examined in unanesthetized ovariectomized rats with or without estrogen priming. Microinjection of glucagon (1.0 microgram) into the medial preoptic area of ovariectomized estrogen-primed rats significantly facilitated the circadian afternoon rise in LH secretion as compared to the hormone values in control animals microinjected with physiological saline. The timing of the afternoon LH rise was not altered by glucagon and the circadian rise of PRL secretion was not altered by glucagon injected in the preoptic area. The injection of GIP did not have any significant effect on either LH or PRL secretion. In ovariectomized estrogen-unprimed rats, on the other hand, glucagon did not affect the pulsatile LH secretion, but it inhibited PRL secretion. GIP did not affect any hormone secretion. The results show that (1) glucagon, as other secretion family peptides such as secretion and PHI, can stimulate the preoptic LH secretory mechanism that undergoes the circadian clock mechanism under the influence of estrogen, and (2) without estrogen priming, glucagon in the preoptic area inhibits PRL secretion.

Animals↗
PubMed1988

Plasma biopterin levels of patients with affective disorders.

The plasma biopterin levels of 13 patients with affective disorders were measured both in the symptomatic phase and in the remission phase, and under no influence of psychotropic drugs except lithium and/or carbamazepine by high-performance liquid chromatography with fluorescence detection, and were compared with those of normal controls. The biopterin levels of patients in the symptomatic phase were elevated significantly as compared with those of normal controls, and the elevation tended to be more pronounced in the hypomanic phase than in the depressive phase. In contrast, the biopterin levels of patients in remission were not different from those of normal controls.

Adult↗
PubMed1988

Quadricuspid aortic valve perforation resulting from bacterial endocarditis--2-D echo- and angiographic diagnosis and its surgical treatment.

A 75-year-old man with quadricuspid aortic valve regurgitation affected by bacterial endocarditis is reported. The aortic valve consisted of 4 equal-sized cusps (type a) and a supernumerary cusp located between the right and noncoronary cusps. A right coronary ostium was close to the accessory commissure, but there was no displacement. A few small fenestrations were found at the 4 commissures and a large perforation resulting from endocarditis was observed in the noncoronary cusp. 2-D echocardiogram and angiogram suggested these findings, and they were confirmed at surgery. Successful aortic valve replacement was achieved.

Aged↗