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Biomedical subjects

H Nagata

Publications and source records attributed to H Nagata.

At least 325 records · Page 18Linked to original sources
PubMed1986

Recognition of concrete and abstract pictures as a function of poststimulus interval.

This study examined picture recognition of concrete common objects and abstract random shapes under two presentation conditions: The durations of the unfilled intervals (off-time duration) that followed the presentation of the pictures were varied either randomly or in blocks. The major findings were: recognition of the concrete pictures was better than recognition of random shapes, the off-time duration did not influence recognition of either type of picture under the random presentation condition, and under the block presentation condition, recognition of the concrete pictures increased as a function of off-time duration, whereas the effect of off-time duration was not found for the abstract shapes. The results were interpreted as suggesting that a longer off-time duration is necessary for abstract shapes so that stimulus differentiation, verbal encoding, visual analogizing, and rehearsing may be utilized in processing.

Form Perception↗
PubMed1986

Thyroidal response to an increase or decrease of endogenous TSH in patients with hyperthyroidism and its correlation with TSH binding inhibiting immunoglobulin.

One hundred and twenty-one patients with hyperthyroidism of Graves' disease were treated with antithyroid drugs for 3 years and thyroidal response to an increase or decrease of TSH and the serum thyroid stimulating immunoglobulin (TSI) activity were studied in relation to the presence or absence of TSH binding inhibiting immunoglobulin (TBII). TBII activity was positive in 83% of untreated patients but decreased gradually with time during antithyroid drug therapy. Thyroidal radioactive iodine uptake (RAIU) was suppressed by T3 in 86 of 121 treated patients but 16% of suppressible patients had TBII activity. Thyroidal RAIU was not suppressed by T3 in 35 treated patients, and 19 of 35 unsuppressible patients had TBII activity but other 16 patients did not. When suppressible and unsuppressible patients were combined, suppression of serum T4 and thyroidal RAIU by T3 tended to be less in the presence of TBII activity. TSI activity was detected in the sera of untreated patients but did not correlate with TBII activity. TSI activity was undetectable after treatment for 3 years irrespective of presence or absence of TBII activity and T3-suppressibility. TSH, T4 and T3 elevation in response to 500 micrograms thyrotropin releasing hormone (TRH) was normal in all treated patients irrespective of presence or absence of TBII activity and T3-suppressibility. It is suggested that in vivo thyroidal responsiveness to an increase or decrease of endogenous TSH did not correlate with the presence or absence of TBII activity after long-term therapy with antithyroid drugs.

Adolescent↗
PubMed1986

Comparable effects of oral diltiazem and verapamil in the treatment of hypertrophic cardiomyopathy. Double-blind crossover study.

The effects of oral diltiazem, 180 mg/day, were compared with those of oral verapamil, 240 mg/day, in 32 patients with hypertrophic cardiomyopathy (HCM), using a double-blind crossover study design. In the first treatment period, diltiazem and verapamil improved subjective complaints in 83% and 71% of those who were symptomatic in the baseline period. Maximal oxygen consumption on exercise stress test increased with verapamil by 2.9 +/- 4.2 ml/Kg/min (p less than 0.05), and tended to increase with diltiazem. Verapamil also reduced the amplitude of negative T wave. In the statistical analysis based on the crossover design, diltiazem and verapamil did not differ in global improvement, overall safety and global utility ratings. In addition, both drugs showed comparable effects on electrocardiographic and echocardiographic variables and exercise tolerance except for minor differences in diastolic blood pressure, T wave amplitude and peak exercise heart rate. On the other hand, verapamil tended to induce more serious side effects, forcing the discontinuation of medication in 3 patients. Therefore, the present study indicates that diltiazem is essentially equally as effective as verapamil and is preferable in the treatment of patients with HCM since it may exhibit fewer serious side effects.

Administration, Oral↗
PubMed1986

Formation of lymph follicles in draining lymph nodes after local injection of various antigenic substances in mice.

Formation of lymph follicles in draining popliteal lymph nodes was examined in 8-week-old, male C57Bl/6 mice which had been injected in the rear footpad with any one of eleven test substances including thymus-dependent and thymus-independent antigens, and killed after 6-14 days. HGG (10-100 micrograms), MGG, tetanus and diphtheria toxoids (2-10 Lf) and influenza HA vaccine (35 CCA) induced germinal centers in association with existing follicles, but failed to produce new follicles in draining nodes. KLH (10-100 micrograms), SRBC (1 X 10(8)) and formalin-killed pertussis organisms (5 X 10(8)) induced germinal centers in existing follicles and also produced new follicles which soon developed germinal centers. Levan and PVP (10-100 micrograms) induced neither germinal centers nor new follicles. Ferritin (100 micrograms) virtually failed to induce germinal centers but produced a significant number of new primary follicles. In further experiments, artificially aggregated substances were examined with regards to their ability of inducing lymph follicle formation in draining nodes. Precipitated proteins such as alum-precipitated PHA, HGG, tetanus and diphtheria toxoids, "Sepharose"-PHA and "Sepharose"-HGG induced a significant number of new follicles. These observations suggest that efficient follicle formation is associated with particulate and high-molecular-weight antigens which are liable to be phagocytized, whereas soluble, poorly phagocytized antigens tend to be inefficient. Soluble proteins may be effective if given in precipitated form. Thymic dependency appears to be irrelevant. The present results point to a possible participation of macrophages in the mechanism of follicle formation.

Animals↗
PubMed1985

Fibronectin. Localization in normal human skin, granulation tissue, hypertrophic scar, mature scar, progressive systemic sclerotic skin, and other fibrosing dermatoses.

The histologic localization of fibronectin (FN) in normal human skin, granulation tissue, hypertrophic scar, mature scar, progressive systemic sclerotic skin, and tissue of other fibrotic disorders was investigated by an indirect immunofluorescence technique using specific antiserum prepared in rabbits against purified human plasma FN. In granulation tissue that developed just after traumatic wounding, FN seemed to increase remarkably in the wound as a fibrillar network. In the hypertrophic scar, one to five years after wounding, FN was detected in a linear or curling arrangement throughout the dermis. On the contrary, FN gradually decreased in the wound of the mature scar five to 20 years after wounding. There were some interesting observations among other diseases. In the skin of patients with progressive systemic sclerosis and morphea, FN was found to be localized faintly on the dermoepidermal junction and papillary dermis. In the involved skin of dermatofibroma, FN was observed in a curling arrangement throughout the dermis.

Adolescent↗
PubMed1985

Heavy metal concentrations in blood cells in patients with amyotrophic lateral sclerosis.

Manganese (Mn) and selenium (Se) concentrations in blood cells were measured by neutron activation analysis. Blood was obtained from patients with amyotrophic lateral sclerosis (ALS), patients with other neurological diseases and control subjects. Dried blood cells were activated by neutron irradiation. Mn was determined after chemical separation and Se was determined nondestructively. Mn concentrations in blood cells from ALS patients were significantly lower (P less than 0.01) than those from the other groups. The Mn concentrations were also significantly lower (P less than 0.01) in late than in earlier stages of ALS. Se concentrations in blood cells from ALS patients were significantly higher (P less than 0.01) than those from the other two groups. A generalized abnormal distribution of these metals may play a role in the pathogenesis of this disorder. Bromine, zinc, rubidium, and iron concentrations of erythrocytes were the same in all groups.

Amyotrophic Lateral Sclerosis↗
PubMed1985

Prostaglandin cytoprotection: role of microcirculatory changes.

Both the fluorescent in vivo microscopic study and the hydrogen-gas-clearance study revealed complete absence of blood flow in the areas of gross ethanol damage. PG pretreatment prevented this cessation of flow. However, the hydrogen-gas-clearance study demonstrated that PG administered in a cytoprotective dose did not increase blood flow. It maintained blood flow by some other mechanism. The final in vivo microscopic studies demonstrated a marked leak of albumin from microvessels and slowing and then cessation of flow very shortly after topical ethanol application. This suggests that an increase in blood viscosity due to plasma leak may be the mechanism of the ethanol-induced flow stasis. PG prevented this leak. PG cytoprotection, by preventing this permeability change, maintains mucosal blood flow and may thus protect the mucosa against the deeper and more severe ethanol injury.

16,16-Dimethylprostaglandin E2↗
PubMed1984

Pathologic laughing and crying treated with levodopa.

Levodopa or amantadine hydrochloride was administered to 25 patients with pathologic laughing and/or crying. This symptom was markedly improved in ten cases, most of which were devoid of a cortical atrophy or a periventricular lucency in computed tomographic scan and also devoid of a severe dementia or a disturbance in activity of daily living. The concentration of homovanillic acid in the CSF of the patients was significantly decreased, whereas the concentration of 5-hydroxyindoleacetic acid remained within the normal limit. Because part of pathologic laughing and crying seems to be caused by the decreased function of the dopaminergic neuron, levodopa or amantadine is worth trying.

Affective Symptoms↗
PubMed1984

Microcirculatory responses to estradiol benzoate in chronic liver damage induced by carbon tetrachloride in the rat.

Microcirculatory responses to estradiol benzoate (ES) under condition of chronic liver damage induced by long-term administration of carbon tetrachloride (CCl4) was investigated in the rat. One hundred and five male rats were divided into the following groups receiving 0.1 mg/100 g body weight ES injected intraperitoneally 5 times per week: controls, exposed to CCl4 alone; rats treated with ES from the fourth week of CCl4 exposure; animals treated with ES from the 11th week of CCl4 exposure. In rats receiving CCl4 alone, liver cirrhosis was induced by 10 consecutive weeks of exposure. Microangiograms of the liver demonstrated conspicuous rarefaction of the vascular tree. On the other hand, animals treated with ES had neither atrophic liver nor rarefaction of the intrahepatic vascular tree. ES produced also intrahepatic neovascular proliferation in the cirrhotic liver. After long-term CCl4 administration, ES treated rats had extremely enlarged nodules with tumor-stain like findings, giving rise to a structure differing from hepatocellular carcinoma which latter generally displays a broom-swept appearance. It is concluded that in providing potent angiogenesis in the liver, ES protects the liver against microcirculatory dearangement and parenchymal damage induced by CCl4.

Angiography↗
PubMed1984

Dopamine-beta-hydroxylase activities in serum and cerebrospinal fluid of aged and demented patients.

Age-related changes in dopamine-beta-hydroxylase (DBH) activities in serum and cerebrospinal fluid (CSF) were determined. In normal subjects, serum DBH activity increased gradually from the 3rd to the 8th decade, but decreased prominently in the 9th decade. DBH activity in CSF did not differ between younger and older subjects. Serum DBH activity decreased significantly in senile dementia of Alzheimer's type (SDAT, 12.2 +/- 8.8 nmoles/min/ml, P less than 0.05), but not in multi-infarct dementia (MID, 13.9 +/- 9.1 nmoles/min/ml) compared to control subjects (17.1 +/- 9.5 nmoles/min/ml). The decrease of serum DBH in SDAT was more prominent in patients with severe dementia and/or severe brain atrophy. DBH activity in CSF was much lower than that in serum and did not correlate with each other. DBH activity in CSF obtained from SDAT patients (1.60 +/- 0.94 nmoles/h/ml) and from MID patients 2.01 +/- 0.99 nmoles/h/ml) were both lower than that from other neurological diseases without dementia (4.04 +/- 3.81 nmoles/h/ml). DBH in CSF from SDAT patients was significantly lower (P less than 0.05) than that from controls, but that from MID did not differ from controls. Noradrenergic nervous dysfunction is partly associated with pathophysiology and life expectancy of senile dementia of Alzheimer's type (SDAT).

Adult↗
PubMed1984

Regional and subcellular distribution in mammalian brain of the enzymes producing adenosine.

The activities of 5'-nucleotidase, 2'-nucleotidase, alkaline phosphatase, and acid phosphatase were measured in rat and autopsied human brains. The four phosphatases in the rat brain showed little change in activity after death. The activities of adenosine-producing enzymes were compared in various parts of rat and human brains. When phosphatase activity was measured at pH 7.5, 5'-nucleotidase showed the highest activity in the most parts of the brain. The activity of 2'-nucleotidase and that of nonspecific phosphatase were almost the same at pH 7.5. However, higher phosphatase activity was observed in all parts of the brain when nonspecific phosphatase activity was measured at pH 10.0 or 5.5. High specific activity of 5'-nucleotidase in the brain was detected in the membranous components, especially in the synaptic membranes. The activity of 2'-nucleotidase was distributed in the soluble and synaptosomal fractions. The highest activity of both alkaline and acid phosphatases was recovered in the crude mitochondrial fraction, with the highest specific activity in the microsomal fraction. Phosphatase activity was distributed widely in the rat brain. The activity of 5'-nucleotidase was high in the medulla oblongata, thalamus, and hippocampus, but low in the peripheral nerve, spinal cord, and occipital lobe. The activity of 2'-nucleotidase was high in the vermis and frontal lobe. The highest acid and alkaline phosphatase activities were detected in the frontal lobe and in the olfactory bulb, respectively. The distribution of the four phosphatases in the autopsied human brain was similar to that in the rat brain. The highest 5'-nucleotidase activity was observed in the temporal lobe and thalamus.(ABSTRACT TRUNCATED AT 250 WORDS)

5'-Nucleotidase↗
PubMed1984

Effect of topical histamine on mucosal microvascular permeability and acid secretion in the rat stomach.

The effect of topical histamine on microvascular permeability to macromolecules was studied in the rat gastric mucosa using a fluorescent in vivo microscopy technique. Acid secretion was measured in the pylorus-ligated rat. A topical dose of 10(-2)M histamine increased acid output to a maximum, which was equal to the maximum values attained by intravenous or subcutaneous histamine. Only in rats pretreated with a beta-adrenergic antagonist did 10(-2) to 5 X 10(-2)M histamine cause leak of a fluorescein-albumin conjugate from mucosal microvessels. Leak occurred around collecting venules but not from capillaries. An H1-receptor antagonist, but not an H2-receptor antagonist, significantly decreased histamine-induced leaks. We concluded the following. 1) topically applied histamine penetrates into the mucosa and can increase acid secretion to the same extent as parenteral histamine. 2) Topical histamine increases microvascular permeability to macromolecules only when beta-adrenergic receptors are blocked. Larger doses of histamine are needed for initiating the permeability change than for initiating the acid secretory response. 3) H1-receptors in venules are involved in the histamine-induced increase in permeability.

Administration, Topical↗
PubMed1984

Reappraisal of the 3,5,3'-triiodothyronine-suppression test in the prediction of long term outcome of antithyroid drug therapy in patients with hyperthyroid Graves' disease.

Thyroidal suppressibility by exogenous T3 in terms of both radioiodine uptake (RAIU) and serum T4 was evaluated in 115 hyperthyroid patients treated with methimazole for 2 yr and followed for an additional 2 yr to study the rate of recurrence. Various other serum parameters including serum thyroglobulin concentrations, thyroid autoantibody, and TSH receptor antibody titers, and thyroidal responses to TRH-induced TSH elevation were also determined. After 2 yr of methimazole therapy, thyroidal RAIU was not suppressible (RAIU less than 12%/4 h was defined as suppressible) in 50 of 115 patients (group I). Of 65 patients with suppressible thyroid RAIU, serum T4 was significantly reduced (less than 60% of pre-T3 level) by T3 administration in only 43 patients (group III) but not in the remainder (group II). Antithyroid drug therapy was discontinued in the group II and III patients, and 7 of the patients had recurrence of hyperthyroidism within 2 yr of follow-up. All of them were from group II. The thyroidal response to TSH was greater in group III patients than in group II patients. During antithyroid drug therapy, decrease of microsomal antibody titer was more likely to occur in group III patients than in those of group II. Serum thyroglobulin concentrations were uniformly normal in treated patients irrespective of T3 suppressibility. TSH receptor antibody was positive in all 13 untreated patients with Graves' disease but was negative in treated patients regardless of their T3 suppressibility. Measurement of both thyroidal RAIU and serum T4 after administration of T3 improves the reliability of T3-suppression testing as a predictor of the remission of Graves' disease.

Adolescent↗