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Biomedical subjects

K Hashizume

Publications and source records attributed to K Hashizume.

At least 19 recordsLinked to original sources
PubMed1979

Anomalous systemic arterial supply to the basal segments of the lung presenting with a murmur.

A murmur was discovered on routine preschool physical examination of a 5 year and 7 month-old boy. A lower lobe lesion was detected by chest X-ray. Aortography demonstrated that a large systemic artery from the descending thoracic aorta supplied the basilar segments of the left lower lobe, which had no normal pulmonary arterial supply. A clinical diagnosis of intralobar sequestration of the lung was made, and left lower lobectomy was performed.

Aorta, Thoracic↗
PubMed1979

Adenosine 3',5'-monophosphate-dependent protein kinase activity in soluble thyrotropin receptor complex.

cAMP-dependent protein kinase activity was present in a soluble TSH receptor fraction. The Km of this enzyme was 2.2 X 10(-6) M for casein substrate in the absence or presence of 10(-5) M cAMP. A [3H]cAMP-binding protein was also found in this fraction. The Ka for [3H]cAMP-binding was 0.11 X 10(6) M-1, with a total binding capacity of 3 nmol/mg protein. After fractionation using a continuous sucrose density gradient, one of the several [125I]iodobovine TSH-binding peaks corresponded to a [3H]cAMP-binding peak. After fractionation on a sucrose density gradient containing 0.4 M NaCl at pH 6.5, a major peak of protein kinase activity was shown. This protein kinase activity was stimulated by adding 10(-5) M cAMP. A peak of [3H]cAMP-binding activity corresponded to the same peak. Protein kinase activity in the receptor fraction was stimulated by adding 6 mg/ml bovine TSH. The soluble TSH receptor fraction also has an adenylate cyclase activity stimulated by TSH. These results suggest that some TSH receptors released from thyroid plasma membranes have associated adenylate cyclase activity and cAMP-dependent protein kinase activity. The receptor, cyclase, and kinase activities may exist in a functional primary receptor unit which is spontaneously released from plasma membranes.

Animals↗
PubMed1979

Cyclic nucleotide-dependent protein kinase modulators in thyroid tissue.

A heat-stable protein which inhibits cAMP dependent protein kinase was prepared from the bovine thyroid 100,000 X g supernatant. This protein inhibited the cAMP-dependent protein kinase both from bovine thyroid cytosol and bovine thyroid plasma membranes. The inhibitory effect was noncompetitive with histone as substrate of the cytosolic enzyme. The stimulatory modulator for cGMP-dependent protein kinase was separated from the 100,000 X g supernatant by Sephadex G-100 gel filtration. The stimulatory modulator had no stimulating effect on cAMP-dependent phosphorylation, and the inhibitory modulator of cAMP-dependent enzyme had no effect on cGMP-requiring phosphorylations. The inhibitory modulator may regulate cAMP-dependent protein kinase activity in cytosol and plasma membrane, and the stimulatory modulator for cGMP-dependent protein kinase may have a role in thyroid function independent of the cAMP-requiring system.

Animals↗
PubMed1979

Changes in thyroid-stimulating immunoglobulins during antithyroid therapy.

Thyroid-stimulating immunoglobulin (TSI) activity was measured by radioreceptor assay in sera from patients with Graves' disease, Hashimoto's thyroiditis, and thyroid cancer. In untreated Graves' disease (47 cases), TSI index was significantly lower [76.7 +/- 1.4 (SE)] than the average of a normal control group (30 cases; 94.4 +/- 1.9). In untreated Hashimoto's thyroiditis (25 cases), it was also significantly lower (83.0 +/- 2.4). In patients with thyroid cancer (19 cases), there was no significant difference from normal controls. After 131I treatment, the TSI index in Graves' disease decreased during 2--4 months, then increased and reached normal levels in 1 yr. During propylthiouracil treatment, the TSI index increased and reached a normal level in 5--6 months without the decreasing phase seen after 131I treatment. Free T4 index values were gradually decreased by both treatments. There was no significant relationship between TSI index and thyroid antibodies (microsomal antibodies and thyroglobulin antibodies) in untreated Graves' disease or Hashimoto's thyroiditis. It is concluded that 1) in the sera of patients with Graves' disease and Hashimoto's thyroiditis, there are immunoglobulin Gs that can displace TSH binding to thyroid membranes; 2) these immunoglobulins Gs are different from the classic antithyroid antibodies; and 3) 131T treatment of Graves' disease may enhance TSI production during the first 1--2 months after therapy.

Adult↗
PubMed1978

Purification and properties of nitroalkane oxidase from Fusarium oxysporum.

A nitroalkane-oxidizing enzyme, which was inducibly formed by addition of nitroethane to the medium was purified to homogeneity from an extract of Fusarium oxysporum (IFO 5942) with an overall yield of about 20%. The enzyme catalyzed the oxidative denitrification of 1-nitropropane as follows: CH2(NO2)CH2CH3 + O2 + H2O leads to OHCCH2CH3 + HNO2 + H2O2. In addition to 1-nitropropane, 3-nitro-2-pentanol, 2-nitropropane, and nitrocyclohexane are good substrates; the enzyme is designated "nitroalkane oxidase" (EC class 1.7.3). The enzyme has a molecular weight of approximately 185,000 and consists of four subunits identical in molecular weight (47,000). Flavin adenine dinucleotide was required for the enzyme activity and could be replaced in part by riboflavin 5'-phosphate. The maximum reactivity was found at about pH 8.0. The enzyme was inhibited significantly by HgCl2, KCN, p-chloromercuribenzoate, and N-ethylmaleimide. The Michaelis constants are as follows: 1-nitropropane, 1.54 mM; 2-nitropropane, 7.40 mM; nitroethane, 1.00 mM; 3-nitro-2-pentanol, 3.08 mM; nitrocyclohexane, 0.90 mM; and flavin adenine dinucleotide, 1.33 micrometer.

Cyanates↗
PubMed1978

The biphasic stimulatory and inhibitory effects of concanavalin A on thyroid activation induced by thyrotropin.

Concanavalin A (Con A) was tested for its ability to affect thyroid activation induced by TSH in mouse thyroid lobes. Pretreatment of thyroid lobes with Con A at concentrations from 1.55--400 microgram/ml was found to have biphasic stimulatory and inhibitory effects of the TSH-induced accumulation of cAMP and formation of colloid droplets. Low concentrations of Con A potentiated TSH activation of thyroidal formation of cAMP and endocytosis. In contrast, higher concentrations of Con A markedly inhibited these TSH effects. The inhibitory effects observed after preincubation with Con A were abolished by the addition of alpha-methyl-D-glucoside to the incubation medium. A high concentration of Con A also inhibited cAMP formation induced either by prostaglandin E2 or the long-acting thyroid stimulator. However, the basal and TSH-stimulated glucose oxidation in mouse thyroid lobes was not depressed by a high concentration of Con A. Uptake of 125 I-labeled Con A by thyroid tissues increased with time up to 1 h and was directly proportional to tissue weight. These findings suggest that the specific interaction between Con A and its receptors may lead to conformational changes in the structure of the membranes of the thyroid follicular cells which facilitate TSH-induced thyroid hormone secretion via the adenylate cyclase-cAMP system.

Animals↗
PubMed1978

Evidence for activation by beta2-adrenergic receptors of adenosine 3',5'-monophosphate formation in Ehrlich ascites tumor cells.

The existence of aminergic receptors in mouse Ehrlich ascites tumor cells was studied. L-Isoproterenol in vitro stimulated the formation of cAMP in isolated Ehrlich ascites tumor cells. Stimulation by isoproterenol of cAMP formation was not significantly inhibited by practolol, a beta1-adrenoceptor antagonist-Salbutamol, a beta2-adrenoceptor agonist, markedly stimulated the formation of cAMP in Ehrlich ascites tumor cells at concentrations from 10(-8)-10(-3) M. After the addition of salbutamol, cAMP levels reached a maximum in 10 min and declined to about 2-fold of the basal level to 30 min. The stimulation by salbutamol of cAMP formation was markedly inhibited by butoxamine, a beta2-adrenoceptor antagonist, but not by practolol. Furthermore, the effect of a maximal dose of salbutamol was additive to that of prostaglandin E2. Histamine and 4-methylhistamine, a histamine H2 receptor agonist, had no significant effects. Therefore, it is suggested that a beta2-adrenergic receptor exists in the membranes of Ehrlich ascites tumor cells in terms of the adenylate cyclase-cAMP system.

Albuterol↗
PubMed1978

Thyroglobulin inhibition of thyrotropin binding to thyroid plasma membrane.

The effect of thyroglobulin (TG) on binding of TSH to thyroid plasma membranes was studied in vitro. Human and bovine thyroid plasma membranes have specific binding sites for bovine [125I]TSH. The binding of [125I]TSH is inhibited by the addition of purified TG (100 ng/microgram/ml). The inhibitory mechanism appears to be noncompetitive when subjected to Lineweaver-Burk analysis. Incubation of TG with TSH did not show an interaction, as assessed by sucrose gradient centrifugation. Plasma membranes prepared from human thyroid tissue have specific binding sites for human TG, as shown by [125I]TG binding assay. The TG binding was not affected by adding low concentrations of unlabeled bovine TSH. In the presence of very high concentrations of TSH, TG binding was increased. Hemoglobin, beta-lactoglobin, and ovalbumin did not have an inhibitory effect on [125I]TSH and [125I] TG binding to membrane preparations. Both [125I]TSH and [125I]TG binding were inhibited by 10 mM neuraminic acid. These results suggested that 1) TG released from thyroid gland may have a regulatory effect on TSH binding to its specific receptor, and 2) there are specific binding sites for TG on the thyroid plasma membrane.

Animals↗
PubMed1977

VEP and SEP in non-specific thalamic nuclei and pulvinar during stereotaxic surgery.

This report is based on recordings of evoked photic (VEP) and somatosensory response (SEP) from the thalamic nuclei and cortex of 17 humans during stereotaxic surgery. The cortical SEP and VEP have relatively uniform patterns. The initial latency of the cortical VEP is shorter than that of SEP. Both thalamic SEP and VEP give relatively constant response to Limitans and Parafascicularis, Centromedian and Pulvinar but Dorsomedial nucleus has a smaller and variable latency. Thalamic SEP gives a better response than thalamic VEP in Nucleus Limitans and Parafascicularis, Nucleus Centromedian, and Pulvinar. This suggests that the non-specific thalamic nuclei, especially Centromedian, Limitans and the nucleus Parafascicularis and Pulvinar, play an important role in pain conduction and function as a relay station in the transmission of non-specific visual impulses. The visual evoked response pattern as well as somato-sensory evoked response from the thalamic nuclei can serve as a very reliable means of controlling the target area prior to subcortical destruction.

Adult↗
PubMed1977

Evidence for the existence of a histamine H2-receptor in the mouse thyroid.

The existence of a histamine H2-receptor in the thyroid was investigated. Histamine in vitro stimulated the formation of cyclic AMP and colloid droplet formation in mouse thyroid lobes. Stimulation by histamine of cyclic AMP formation in mouse thyroid lobes was significantly inhibited by metiamide, a histamine H2-receptor antagonist. 4-Methylhistamine, a histamine H2-receptor agonist, markedly stimulated cyclic AMP formation, whereas 2-methylhistamine, a histamine H1-receptor agonist, was ineffective. The stimulation by 4-methylhistamine of cyclic AMP formation was markedly inhibited by metiamide, but not by chlorpheniramine, a histamine H1-receptor antagonist. In contrast, metiamide did not affect cyclic AMP formation induced either by TSH or by the long-acting thyroid stimulator. Therefore, it is suggested that there exists a histamine H2-receptor in the membranes of the thyroid follicular cells which facilitate thyroid hormone secretion via the adenylate cyclase-cyclic AMP system.

Animals↗
PubMed1977

Chloride-induced contraction in a skinned fiber of toad striated muscle.

Cl- -induced contraction was studied in a skinned fiber dissected from toad sartorius muscle. When K-methanesulphonate in a relaxing solution was replaced isotonically with KCl, the skinned fiber contracted due to 'depolarization'-induced Ca++ release on the SR. Contraction was induced by superfusing the fiber with solutions containing different concentrations of Cl-. In the presence of 2 mM EGTA, the Cl- -induced contraction developed when the relaxing solution was replaced by a Cl- solution which contained up to 20 mM Cl-, while contraction started at 15 mM-Cl- in the presence of 0.5 mM EGTA. The peak tension of the Cl- -induced contraction depended on Cl- concentration without obeying the all-or-none law. When the fiber was treated with 1.5 mM caffeine, the threshold for the Cl- -induced contraction was significantly lowered. In spite of previous application of Cl- at different concentrations below 80 mM, the skinned fiber contracted by sudden increase in Cl- concentration, and the tension versus Cl- concentration curve revealed almost the same shape as that in a fiber equilibrated with Cl- -free solution. This suggests that the SR membrane is repolarized after transient depolarization caused by elevation of Cl- concentration.

Animals↗
PubMed1977

Effects of biogenic amines on the formation of adenosine 3',5'-monophosphate in human thyroid slices.

The effects of various concentrations of biogenic amines on the formation of adenosine-3', 5'-monophosphate (cyclic AMP) and their interactions with other thyroid stimulators were investigated in human thyroid slices from normal and Graves' disease. Most of biogenic amines were found to have the stimulatory effects to some extent. Among the biogenic amines tested, histamine was the most potent thyroid stimulator, norepinephrine and serotonin, the intermediate in terms of cyclic AMP formation. The effect of histamine was almost as potent as TSH in thyroid slices from Graves' disease. This stimulatory effect of histamine was blocked by metiamide, a histamine H2-receptor antagonist, but not by chlorpheniramine, a histamine H1-receptor antagonist. The effect of norepinephrine was completely inhibited by propranolol, but not by phentolamine. Polyphloretin phosphate did not inhibit norepinephrine- or histamine-induced cyclic AMP formation, while it significantly depressed cyclic AMP formation induced by prostaglandin E2. The maximal effect of histamine was additive to that of TSH. It is suggested that biogenic amines, histamine and norepinephrine, in particular, have the thyroid receptors different from that of TSH or prostaglandin E2 and could play an important role in thyroid physiology.

Catecholamines↗