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Biomedical subjects

K Noguchi

Publications and source records attributed to K Noguchi.

At least 523 records · Page 29Linked to original sources
PubMed1981

Illusions of filled lateral and angular extent. The role of cortical feature detectors.

The common principle of the illusions found by Helmholtz and Botti is the overestimation of a filled extent. They differ in that Helmholtz's illusions of filled angular extent can be accounted for in terms of spatial two-line interactions, whereas Botti's illusions of filled lateral extent cannot. The former observation is consistent with the assumption of interacting orientation-detectors in the visual cortex. The Botti illusion probably depends on global computation in the visual system.

Humans↗
PubMed1981

A neglected problem: kinetic size constancy.

Size constancy in three-dimensional motion, "kinetic size constancy", was investigated by measuring both perceived size and perceived distance under monocular and binocular viewing conditions. It was found that forward-motion facilitated a tendency to see an object with an approximately constant size and made it possible to perceive veridically the distance to the object (distance constancy). The size-distance invariance hypothesis, expressed in the form S'/D'=K theta n, was found to hold in the present experimental situation. In contrast to static size constancy, with kinetic size constancy there is no requirement for separate depth cues if a focal stimulus changes along its vertical and horizontal dimensions and this results in the perception of a shape.

Depth Perception↗
PubMed1981

Effect of Iopanoic acid on the pituitary-thyroid axis: time sequence of changes in serum iodothyronines, thyrotropin, and prolactin concentrations and responses to thyroid hormones.

We have previously shown that some oral cholecystographic agents induce marked increase in basal and TRH-stimulated TSH concentrations in normal subjects. To define the relationship between circulating iodothyronines and pituitary secretion after oral cholecystography, temporal changes in the responses of serum TSH and PRL to a fixed dose of TRH (500 micrograms iv) and in serum T4, T3, and rT3 concentrations were assessed before, immediately after, and then at weekly intervals after the three daily doses of iopanoic acid (Ip). Both basal and TRH-stimulated TSH concentrations were significantly increased at the end of the period of Ip administration when the serum T3 concentration was decreased, were still above the pretreatment level 1 week after the course of Ip when the serum T3 had returned to pre-Ip levels, and returned toward normal 2 weeks after the course of Ip. The changes in serum T3 concentration were accompanied by reciprocal changes in rT3 concentration. PRL secretion was not significantly changed. To evaluate further the relationship between the enhanced TSH secretion and the changes in serum iodothyronine concentrations, subjects were given oral doses of T3 (5 micrograms every 4 h) or T4 (50 micrograms every 8 h) during the administration of Ip. In the subjects given Ip plus T3, serum T3 concentrations were maintained at pre-Ip levels, and both basal and TRH-stimulated TSH concentrations were not different from the control. Administration of T4 did not completely prevent the Ip-induced increment of TSH secretion. It is suggested that in subjects given Ip, 1) the serum T3 level is, at least partly, a determining factor for TSH secretion; and 2) the set-point of TSH secretion is appropriately tuned to either reduction or elevation of serum T3 concentration by a mechanism that is different from that in fasting subjects.

Adult↗
PubMed1981

Difference in site and time course of coronary dilating effects of trapidil, nitroglycerin and dipyridamole in anesthetized dogs.

Effects of trapidil, a non-nitrate type coronary vasodilator, nitroglycerin and dipyridamole on epicardial coronary diameter and total coronary resistance were studied in anesthetized open-chest dogs. The epicardial coronary diameter of the left circumflex coronary artery was measured by sonomicrometry and total coronary resistance was calculated by aortic pressure and coronary blood flow. Intravenous administration of Trapidil, as well as nitroglycerin, produced transient decreases in total coronary resistance followed by sustained dilation of the large coronary artery. Dipyridamole increased coronary blood flow by 2.7-fold, whereas diameter of the large coronary artery decreased along with the reduction of aortic pressure. The first peak of the biphasic increases in coronary blood flow and subsequent dilation of the large coronary artery appeared after an i.v. bolus administration of trapidil or nitroglycerin and remained even after beta adrenergic blockade. Intracoronary administration of either drug produced monophasic increases in coronary blood flow along with subsequent dilation of the large coronary artery. Thus, trapidil, like nitroglycerin, directly dilates the large and small coronary arteries.

Animals↗
PubMed1981

Atypical malignant histiocytosis. Its appearance as a single meningeal tumor or as multiple skin tumors.

We studied two unusual cases of malignant histiocytosis (MH). In one case, a solitary intracranial tumor developed in a 20-year-old man eight months before the characteristic symptoms of MH appeared. In the other, a 73-year-old man had multiple nodular skin lesions four months before malignant histiocytes appeared in his blood. In both, the tumor cells were identified as malignant histiocytes by light and electron microscopic, cytochemical, and cytoimmunological criteria.

Adolescent↗
PubMed1981

Pluripotent, erythrocytic and granulocytic hemopoietic precursors in chronic granulocytic leukemia.

Using methylcellulose culture techniques, we investigated the behavior of committed and pluripotent hemopoietic precursors (CFUMIX) in marrow cells and blood from patients with chronic granulocytic leukemia (CGL) in the chronic phase whose marrow cells showed the presence of Ph1 chromosomes. The relative concentrations of the marrow precursors in CGL were nearly equal to those in control patients. The mean nucleated cell count in marrow fluid from the patients, however, was 6.3 times that of control values. As a result, the mean concentrations per unit volume of the hemopoietic precursors in CGL were significantly higher than those in control patients. Furthermore, the presence of erythropoietin (Ep) independent BFUE giving rise to erythropoietic bursts in the medium without the addition of Ep was demonstrable in marrow cells and blood. In the peripheral blood, the increment in numbers of CFUC, CFUE, BFUE, and CFUMIX in accordance with the leucocyte count was observed. The present results are consistent with the theory that the clonal expansion in CGL occurs at the level of pluripotent hemopoietic precursors and suggest that CFUMIX in CGL can differentiate into CFUE along the erythropoietic pathway and that a regulatory defect in CGL in present in both granulocytic cells and erythrocytic cells.

Adult↗
PubMed1981

[Study of endometrial hyperplasia employing the method of micro-electrophoresis of cultured cells of hyperplastic endometrium (author's transl)].

Endometrial hyperplasia was studied from the point of view of cell surface charge employing micro electrophoresis. Surface change of cells corresponding to the cyclic changes of cell multiplication as well as estrogen and/or progesterone effects on the cellular surface charges on each phase of the cell cycle. The results as follows: 1. Electrophoretic mobility was highest in mitotic phase. This result was indicative of what the cell-surface charge was closely related to cell multiplication. 2. Estrogen clearly elevated electrophoretic mobility of cells in synthetic phase. Progesterone lowered electrophoretic mobility of cells in G1 phase. These results indicate that multiplication was forced in synthetic phase by estrogen and differentiation in G1 phase by progesterone. 3. Effects of estrogen and progesterone to cultured pulmonary cancer cells were studied as control to endometrial ones which might be target to these hormones. No definite results as previously shown on endometrial cells were obtained on the pulmonary ones. As a result, it is apparent that endometrium is a target to these hormones. Determination of the cellular surface charge by cell micro electrophoresis indicated that estrogen might play an important role in triggering abnormal proliferations of the endometrium.

Cell Cycle↗
PubMed1981

Clonal nature of pluripotent hemopoietic precursors in vitro (CFU-mix).

Direct evidence is presented for the clonal nature of the mixed colonies from pluripotent hemopoietic precursors in vitro in adult murine marrow cells. Bone marrow cells from BDF1 mice were fractionated using the technique of velocity sedimentation according to Miller and Phillips to enrich the concentration of the mixed colony-forming units. After 3 h sedimentation, marrow cells in the 15th fraction were harvested and cultured using a methylcellulose culture assay. After 2 days of culture, dividing single cells were individually aspirated and transferred to fresh culture medium for mixed colonies using a Leitz micromanipulator. 92 macrophage-granulocyte colonies, 11 erythropoietic bursts, and 4 mixed colonies were detected in 358 single-cell culture experiments. The present results indicate that mixed colonies are clonal, and the mixed colony-forming units are pluripotent.

Animals↗
PubMed1980

Negative feedback effects of chlormadinone acetate and ethynylestradiol on gonadotropin secretion in patients with prostatic cancer and male rats.

Serum LH and FSH levels were determined before and after LH-RH injection (100 micrograms, i.m.) in patients with prostatic cancer who were chronically treated with either chlormadinone acetate (CMA, 100 mg/day) or ethynylestradiol (EE, 1 mg/day). In patients treated with EE, the levels of serum LH and FSH before and after injection of LH-RH were significantly lower than those in controls. On the other hand in patients treated with CMA, the basal levels of serum gonadotropins did not differ from those in controls, and the increase in gonadotropin after LH-RH injection was comparable to that in controls. To examine the effects of these steroids on the hypothalamo-hypophysial axis in the regulation of gonadotropin secretion, CMA or EE was implanted in castrated male rats. CMA, EE or cholesterol (control) was implanted in the hypothalamic median eminence-arcuate nucleus region through a stainless doublecannula. EE implantation resulted in a 75% decrease in serum LH (p < 0.001) and a 38% decrease in serum FSH (p < 0.05) from the control levels on day 5 of implantation. On the other hand, CMA implantation induced a 33% decrease in serum LH (p < 0.05) from the control level on day 3 of implantation, but no significant change in serum FSH levels. The injection of 2 micrograms/kg of LH-RH on day 7 of implantation induced significant lowering of LH and FSH levels. There was no significant difference between serum levels of the hormones 20 min after LH-RH injection for these two groups and those for the control group. These studies suggest that EE has a potent negative feedback effect on both LH and FSH secretion, and that CMA has a mild negative feedback effect on LH secretion.

Aged↗
PubMed1980

[Activation analysis of mercury in head hair of dentists (author's transl)].

Mercury contents in head hair of 58 dentists, working at the hospital of Nihon University School of Dentistry were determined using neutron activation analysis. The values ranged from 2.47 ppm to 13.7 ppm. The frequency distribution of the mercury contents increased steeply at about 2 ppm to the maximum of 4 approximately 5 ppm, and decreased to about 11 ppm, its distribution pattern followed a log-normal one with a median of 5.46 ppm. The dentists were divided into two groups and the mercury contents in head hair of them were compared with each other. The arithmetic and geometric means of the values for dentists who handled amalgam in dental practice were 5.66 ppm (SD +/- 1.80) and 5.40 ppm (SD multiplied/divided by 1.36), while those for the dentists who did not handle amalgam in dental practice were 5.96 ppm (SD +/- 2.82) and 5.38 ppm (SD multiplied/divided by 1.59). The values of them agreed well with each other. The arithmetic mean for all dentists was 5.79 ppm (SD +/- 2.28) and the geometric mean of them was 5.40 ppm (SD multiplied/divided by 1.46). They were much lower than the values reported by Suzuki, Miyazawa or Sairenji, et al. in the past year, and they agreed well to those for normal Japanese men with the same age. Therefore it is concluded that proper mercury handling might be established in the dental office.

Activation Analysis↗