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Biomedical subjects

T Ono

Publications and source records attributed to T Ono.

At least 757 records · Page 42Linked to original sources
PubMed1992

Spatial responsiveness of monkey hippocampal neurons to various visual and auditory stimuli.

To investigate involvement of the hippocampal formation in spatial information processing, activity of neurons in the hippocampal formation of the conscious monkey was recorded during presentation of various visual and auditory stimuli from several directions around the monkey. Of 1,047 neurons recorded, 106 (10.1%) responded to some stimuli from one or more directions. Of these 106 neurons with directionally differentiating responsiveness, 49 responded to visual stimulation, 35 to auditory stimulation, and 22 to both. Among 81 neurons, each tested with more than 10 different stimuli, one type responded independent of the nature of the stimulus (nonselective, n = 39), and responses of the other type depended on the nature of the stimulus (selective, n = 42). To investigate effects of change in spatial relations between test stimuli and background stimuli fixed on the monkey or fixed in the environment, 59 of 106 neurons were tested while the experimental apparatus holding the stimulus was moved relative to the monkey. Of these 59 neurons, 36 changed their responsiveness; 7 maintained the magnitude of their responses but changed the response direction with the movement of the apparatus, 5 changed direction regardless of the movement, and 24 did not change direction, but decreased or extinguished responses from the preferred direction. Thirty-two of 106 neurons were also tested by rotating the monkey. The directionally differentiating responsiveness of 11 neurons followed the monkey (egocentric neurons), that of 9 remained in place in the environment (allocentric neurons), and responses of 12 were reversibly extinguished when the monkey was rotated. The results suggest that these hippocampal neurons may be involved in identification of relations among various kinds of stimuli in different spatial frameworks (egocentric or allocentric) and this identification may be developed from multiple sensory modalities.

Acoustic Stimulation↗
PubMed1992

Genetic linkage between copper accumulation and hepatitis/hepatoma development in LEC rats.

The concentration of copper in the livers of Long-Evans rats with cinnamon-like coat color (LEC), in which hepatitis and then hepatomas develop spontaneously, was recently found to be abnormally high. Therefore, we examined the copper concentrations in the livers of LEC F1 backcrosses (LEC F1 x LEC) to determine the linkage of copper accumulation with development of hepatitis. Consistent with a previously reported ratio of rats with hepatitis to rats without hepatitis of about 1:1, hepatitis developed in 14 of 30 F1 backcrosses. The copper concentrations in the livers of all LEC F1 backcrosses with hepatitis were abnormally high and comparable to those of LEC rats. In contrast, the concentrations in all backcrosses without hepatitis were similar to those in normal Long-Evans with agouti coat color or Brown-Norway rats. Copper accumulation was shown to be closely linked with the development of hepatitis in LEC rats and appeared to be a possible cause of hepatitis. The concentrations of copper in the livers of Fischer 344 rats after carbon tetrachloride treatment were in the range for normal liver, indicating that a high copper concentration in the liver is specific to LEC rats and not a specific characteristic of hepatitis. Furthermore, we found that the size and level of ceruloplasmin mRNA in the livers of LEC rats were the same as those in LEA rats and that the size and level of ceruloplasmin polypeptide in their livers and plasma were almost the same as those in LEA rats. Therefore, these results suggest that the copper accumulation is not due to alteration of expression or to gross alteration of the ceruloplasmin gene.

Animals↗
PubMed1992

Relationship between muscle fatigue and oxygen uptake during cycle ergometer exercise with different ramp slope increments.

The surface electromyogram (EMG) from active muscle and oxygen uptake (VO2) were studied simultaneously to examine changes of motor unit (MU) activity during exercise tests with different ramp increments. Six male subjects performed four exhausting cycle exercises with different ramp slopes of 10, 20, 30 and 40 W.min-1 on different days. The EMG signals taken from the vastus lateralis muscle were stored on a digital data recorder and converted to obtain the integrated EMG (iEMG). The VO2 was measured, with 20-s intervals, by the mixing chamber method. A non-linear increase in iEMG against work load was observed for each exercise in all subjects. The break point of the linear relationship of iEMG was determined by the crossing point of the two regression lines (iEMGbp). Significant differences were obtained in the exercise intensities corresponding to maximal oxygen uptake (VO2max) and the iEMGbp between 10 and 30, and 10 and 40 W.min-1 ramp exercises (P < 0.05). However, no significant differences were obtained in VO2max and VO2 corresponding to the iEMGbp during the four ramp exercises. With respect to the relationship between VO2 and exercise intensity during the ramp increments, the VO2-exercise intensity slope showed significant differences only for the upper half (i.e. above iEMGbp). These results demonstrated that the VO2max and VO2 at which a nonlinear increase in iEMG was observed were not varied by the change of ramp slopes but by the exercise intensity corresponding to VO2max and the iEMGbp was varied by the change of ramp slopes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Intestinal fatty acid-binding protein as a sensitive marker of intestinal ischemia.

Determination of the serum level of intestinal fatty acid-binding protein has been used to detect rat intestinal ischemia following ligation or 30-min occlusion of the superior mesenteric artery. The normal values were under the minimal detectable level of less than 2 ng/ml in all the 10 rats. The serum fatty acid-binding protein level increased rapidly, to 340.7 +/- 54.6, 438.5 +/- 40.1, 388.1 +/- 37.4, and 292.2 +/- 95.7 ng/ml (P less than 0.01) at 1, 2, 4, and 8 hr after ligation, respectively. It also increased, to 347.2 +/- 127.7 ng/ml (P less than 0.01) at 1 hr, after a 30-min transient occlusion and then returned to a normal level. Histological studies showed destruction of the villi, disappearance of the mucosa, and transmural necrosis with the progress of time after ligation, while no remarkable morphological change was observed following 30-min transient occlusion. These observations strongly suggest that the intestinal fatty acid-binding protein is a useful biochemical marker for intestinal ischemia, particularly in the early reversible phase.

Alkaline Phosphatase↗
PubMed1992

Induction of external abnormalities in offspring of male mice irradiated with 252Cf neutron.

To assess the genetic effects of fission neutron, the induction of external malformations was studied in F1 fetuses after F0 male mice were irradiated. Male mice of the ICR:MCH strain were irradiated with 252Cf neutron at doses of 0.238, 0.475, 0.95 and 1.9 Gy. They were mated with non-irradiated female mice at 71-120 days after the irradiation. Pregnant females were autopsied on day 18 of gestation and their fetuses were examined for deaths and external abnormalities. No increases of pre- and post-implantation losses were noted at any dose. External abnormalities were observed at rates of 1.40% in the 0.238 Gy, 2.23% in the 0.475 Gy, 3.36% in the 0.95 Gy and 3.26% in the 1.9 Gy groups; the rate in the control group was 1.65%. The dose-response curve was linear up to 0.95 Gy, and then flattened out; the induction rate of external abnormalities was 2.7 x 10(-4)/gamete/cGy based on the linear regression. These results indicated that fission neutron effectively induces external abnormalities in F1 fetuses after spermatogonial irradiation.

Abnormalities, Radiation-Induced↗
PubMed1992

In vivo assessment of drug sensitivity of African trypanosomes using the akinetoplastic induction test.

Following treatment of mice infected with Trypanosoma congolense or T brucei brucei with various doses of isometamidium chloride or diminazene aceturate, the induction of akinetoplastic (AK) forms was observed in the trypomastigotes of both species within 10 hours of drug administration. The levels of AK-induction were closely correlated with the levels of resistance to each compound found using a standard in vivo drug assay in mice. In general, ineffective doses of either compound conferred AK-induction rates of less than 30 per cent; relapsing cases had between 30 and 50 per cent while curative doses had AK-induction rates of 50 per cent or more. In vivo determination of AK-induction rates using ordinary light microscopy is thus a potentially feasible alternative indicator to the conventional use of mice infection and treatment methods for assessing drug sensitivity in African trypanosomes.

Animals↗
PubMed1992

Rat exploratory behavior controlled by intracranial self-stimulation improves the study of place cell activity.

This report is limited to the description of a procedure that should help to resolve the question whether firing fields of hippocampal place cells are relatively stable or modifiable by learning. Rats implanted with lateral hypothalamic electrodes for rewarding intracranial self-stimulation (ICSS) were trained to explore a circular open field (100 cm in diameter) while their locomotion was tracked by a computerized video system which also delivers ICSS whenever the animal's exploration has met certain experimenter defined criteria. The 3 following conditions were examined. (1) Homogeneous exploration of the entire field: ICSS was delivered after the animal repeatedly visited 5 equal segments of the field (central annulus and remainders of the 4 quadrants), entered randomly located circular areas of the field, and/or traveled a criterion distance. (2) Place field contingent reward or non-reward: ICSS was delivered when the animal entered a circular area (23 cm in diameter) corresponding to the place field after a previous visit to a similar area outside the place field. These conditions were reversed in the following task. (3) Delayed reward: ICSS was delivered when the animal entered the circular area and remained in it for 2 s. Each condition was tested for 600 s or until 50 ICSS were delivered. The behavioral procedures described make it possible to propose an experimental protocol that allows examination of the same place cell under conditions of homogeneous exploration with a segment condition or randomly distributed reward and under conditions with the place field signaling reward or non-reward. The delayed reward condition increases the accuracy of the target location and allows assessment of the phasic versus tonic nature of the place cell firing.

Animals↗
PubMed1992

Hippocampal neuronal damage after transient forebrain ischemia in monkeys.

To investigate cerebral injury in the monkey due to transient ischemia, monkeys were each subjected to temporary occlusion of eight (bilateral common carotid, internal and external carotid, and vertebral) major arteries. After 0 (control), 5, 10, 13, 15, and 18 min occlusion, blood flow was restored. The monkeys were sacrificed by perfusion fixation 5 days after the operation, and all brain regions were then histologically examined for ischemic neuronal changes induced by the occlusion. The amplitude of EEG signals from skull and scalp became almost isoelectric within 1-6 min after the onset of occlusion. The EEG signals from the hippocampus were markedly attenuated within 1-4 min, although they did not become completely isoelectric. Blood pressure was significantly increased after 10-min ischemia. Five-min occlusion produced no ischemic neuronal changes except a slight increment of glial cells in the striatum and III, V, and VI layers of the neocortices. After 10- to 15-min occlusion, there were ischemic cell changes restricted exclusively to the CA1 subfield of the hippocampus. Eighteen-min occlusion produced more prominent ischemic neuronal damage in the CA1 subfield of the hippocampus, but ischemic neuronal damage was no longer confined to the hippocampus. These results suggest that only the CA1 subfield of the monkey hippocampus could be damaged by mild ischemic insult. We demonstrate that the limited lesion of the hippocampus, especially the CA1 subfield, after 10- to 15-min occlusion of eight arteries in the monkey, produces a model equivalent to human amnesia caused by transient ischemic insult.

Animals↗
PubMed1992

Cholinergic regulation of the phosphoinositide second messenger system in the guinea pig organ of Corti.

The effect of cholinergic agents on the phosphoinositide second messenger system was investigated in the cochlea of the adult guinea pig in vivo and in vitro. In vivo, phospholipids were labeled with [32P]-orthophosphate by perilymphatic perfusion and their hydrolysis assayed in 'chase' experiments with non-radioactive orthophosphate. Carbachol (1 mM) reduced the content of 32P-labeled phosphatidylinositol 4,5-bisphosphate in the organ of Corti from 31% to 21% of total 32P-lipids, indicating stimulated hydrolysis. The pharmacology of this effect was studied in detail in vitro via the release of inositol phosphates from phosphoinositides pre-labeled with 3H-inositol. Release was increased 2-fold by 1 mM carbachol, 1.6-fold by 1 mM muscarine, but was unaffected by dimethylphenylpiperazinium; the stimulation was blocked by 1 microM atropine but not mecamylamine. These responses indicate the coupling of phosphoinositides to a muscarinic receptor. Furthermore, stimulated inositol phosphate release was higher in the base of the organ of Corti than in the apex which correlates with the increased cholinergic efferent innervation of outer hair cells in the basal region. These results suggest that muscarinic-stimulated inositol phosphate release occurs at the level of the outer hair cell and thus may have an important modulatory role in auditory transduction.

Animals↗
PubMed1992

A case of adult T cell leukemia with bullae in the palmoplantar regions followed by a crisis.

A 48-year-old Japanese female who had had chronic ATL for 4 years suddenly developed vesicles on the palms and soles. Histologically, these bullae were specific lesions of ATL. After a tendency toward improvement, a crisis appeared with increases in the following: peripheral white blood cells, atypical lymphocytes, CD25 positive cells, serum LDH, and soluble IL-2R. Palmoplantar bullae, a rather rare finding, may be indicative of a following crisis.

Female↗
PubMed1992

Expression of CA 50 in normal human skin: comparative study of CEA and CA 19-9.

Normal skin specimens from different body sites were estimated for the expression of CA 50 in comparison with CA 19-9 and CEA. Expression of CA 50 and CA 19-9 was observed in the ductal system and a small part of the secretory portion of eccrine units, but never in any other skin components including apocrine units. CEA was expressed on the ductal and a small part of the secretory portion of apocrine units as well as on those of eccrine units. However, the expression pattern and intensity in eccrine units were different from those of CA 50 or CA 19-9. We concluded that CA 50 was strongly expressed in the normal ductal system of eccrine units and hence could be standardized to stain the eccrine ductal portion and that immunohistochemical comparative studies with CA 19-9 or CEA might be a good methodological technique for discriminating an eccrine or apocrine origin for some skin disorders.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1992

BCC-associated amyloidosis with a peculiar pattern of deposition.

An 83-year-old Japanese woman with lepromatous leprosy had been treated in a leprosarium. More than 10 years ago, she developed a dome-like brown tumor on the dorsum of the nose which showed the histology of basal cell carcinoma. The lesion was a well bordered, rounded tumor with tumor cell nests on its periphery extending toward the center as cords of tumor nest and with amyloid depositions between the cords. The tumor nests and amyloid lessened toward the center of the tumor, being replaced by collagen fibers. Amyloidosis showing this peculiar pattern of transition was reported with a review of published cases.

Aged↗
PubMed1992

Analysis of expression and soluble form of intercellular adhesion molecule-1 in malignant melanoma.

The effects of interferon (IFN) on the expression of ICAM-1 in human melanoma cell lines and the shedding of ICAM-1 into spent media were investigated using an indirect binding assay and a double determinant immunoassay (DDIA). While IFN increased the level of expression of ICAM-1 on melanoma cell lines, the susceptibility to IFN differed according to cell line. The enhancing effect of IFN-gamma was concentration-dependent, and it exceeded those of IFN-alpha and IFN-beta. Shedding of ICAM-1 into spent media was detected effectively, and the results agreed well with the expression of ICAM-1 on melanoma cells. Immunostaining of the surgically removed melanoma lesions was positively correlated with the thickness of the primary lesion. The expression of ICAM-1 in primary melanoma lesions was inversely correlated with the disease-free interval. The circulating ICAM-1 with stage 4 melanoma patients significantly exceeded that of stage 1-3 melanoma patients. These observations suggest that ICAM-1 in its soluble form may play an important role in host immunities and may be useful in evaluating the prognosis of patients with melanoma.

Cell Adhesion Molecules↗
PubMed1992

Bactericidal activities of rat defensins and synthetic rabbit defensins on Staphylococci, Klebsiella pneumoniae (Chedid, 277, and 8N3), Pseudomonas aeruginosa (mucoid and nonmucoid strains), Salmonella typhimurium (Ra, Rc, Rd, and Re of LPS mutants) and Escherichia coli.

Rat defensins were purified and tested for in vitro bactericidal assay against gram-positive and gram-negative bacteria. Staphylococcus aureus (209P, Cowan I, Smith diffuse and Smith compact) were resistant to defensins, whereas Staphylococcus epidermidis, Staphylococcus saprophyticus, Micrococcus lysodeikticus and Bacillus subtilis were less sensitive. Gram-negative bacteria, such as Pseudomonas aeruginosa (mucoid and K) and Klebsiella pneumoniae (Chedid, 277, and 8N3 which were heavily capsulated, moderately capsulated and noncapsulated, respectively) were all very sensitive to defensins and killed within 20 min. Escherichia coli was moderately sensitive and the rough mutants of lipopolysaccharide (LPS) of Salmonella typhimurium LT2, such as Ra, Rc, Rd, and Re were equally sensitive to defensins, being killed within 40 min. Lysozyme did not show any bactericidal activity except against M. lysodeikticus and B. subtilis, whereas it enhanced the bactericidal activity of defensins against P. aeruginosa, E. coli, and K. pneumoniae and suppressed the killing activity of defensins against S. typhimurium and S. aureus. With regard to the three synthetic rabbit defensins, NP1, NP4, and NP5, NP1 showed strong bactericidal activity against K. pneumoniae 277, comparable to that of rat defensins. Neither NP4 nor NP5 showed any bactericidal activity, while NP5 rather enhanced the bactericidal activity of NP1 against K. pneumoniae 277.

Animals↗
PubMed1992

Growth inhibition by anchorage-deficiency is associated with increased level but reduced phosphorylation of mutant p53.

Human breast carcinoma MCF-7 cells seeded on type I collagen-coated dishes were provided with an anchor via the collagen receptor, integrin, and grew as actively as those in plastic tissue culture dishes. In contrast, cells seeded on a layer of soft agar became anchorage-deficient and their growth was significantly inhibited, although the cell viability and the cell cycle distribution were unaffected. Immunoprecipitation analysis revealed that mutant p53 was phosphorylated at tyrosine in the anchorage-provided cells. In contrast, the p53 in the anchorage-deficient cells was present in 2-fold greater amount, but was phosphorylated to a lesser extent. Addition of a potent protein-tyrosine kinase inhibitor, herbimycin A, to the anchorage-provided cells caused an elevated level of p53, and inhibitions of cell proliferation and p53 phosphorylation, without interfering with the cell adhesion to the substratum. These results demonstrated that the growth inhibition by anchorage-deficiency or by herbimycin A is associated with an elevated p53 level and reduced p53 phosphorylation at tyrosine.

Amino Acids↗
PubMed1992

Analysis of antigenic determinants shared by two different allergens recognized by human T cells: house dust mite (Dermatophagoides pteronyssinus) and chironomid midge (Chironomus yoshimatsui).

To analyse the cross-reactivity of T-cell-mediated immunity between Dermatophagoides pteronyssinus (Dp) and Chironomus yoshimatsui (Cy), the most common allergens in Japan, we established antigen-specific human T-cell lines and clones. Some but not all of the Cy-induced T-cell lines showed a significant proliferative response not only to Cy, but also to Dp. No T-cell line responded to other unrelated antigens. When we stimulated the Dp-induced T-cell clones with Cy, 3 of the 40 clones (7.5%) showed a significant proliferation, and 2 of the 3 clones produced interleukin-4 and interferon-gamma, indicating their helper function. Cross-reactivity was diminished significantly after the absorption of Dp antigen in an anti-Cy affinity column. The cross-reactive epitopes were thought to be expressed on the Dp molecule of 45-53 kD. The presence of helper T cells reactive to both allergens suggests a possibility that this cross-reactivity might be involved in part in the high incidence of allergy to the 2 major allergens.

Allergens↗