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Biomedical subjects

K Hashizume

Publications and source records attributed to K Hashizume.

At least 343 records · Page 19Linked to original sources
PubMed1990

[Present status of neuroblastoma mass screening in Japan. Neuroblastoma-Committee of the Japanese Childhood Cancer Society].

In 1973, mass screening program for 6-month old infants for early detection of neuroblastoma using a VMA spot test of a urine sample was initiated in Kyoto. In 1985, nation wide mass screening was initiated throughout the entire country and the Government has given the financial support to each district. In 1988, the Government recommended the institution of mass screening by quantitative measurements of VMA, HVA and creatinine using HPLC (high performance liquid chromatography), instead of the qualitative test of VMA alone. From 1974, at the time of initiation of mass screening for neuroblastoma to the end of October, 1989, 383 cases with this tumor have been discovered throughout the screening program. Three hundreds eighty three cases (88%) of them had been registered to the Neuroblastoma Committee of the Japanese Society of Pediatric Oncology. In this paper, the mass screening program was introduced and the 337 cases with this tumor detected by 6-month old screening were analyzed their clinical symptoms, findings, urinary VMA and HVA levels, primary sites, weights of primary tumor, histology, stages at diagnosis, metastatic sites, and the results of the treatment. Three hundreds twenty eight cases (97%) of them are expected to be cured. And we discussed clinical problems related to mass screening program for neuroblastoma, such as an increase of the incidence of infantile neuroblastomas detected by this program and the spontaneous regression.

Adolescent↗
PubMed1990

[Effects of controlled hypotension induced by prostaglandin E1 on the cerebral blood flow].

The effect of controlled hypotension induced by prostaglandin E1 (PGE1) on the cerebral blood flow (CBF) was studied in 14 patients undergoing neurosurgery. CBF was measured by thermal diffusion using a flow probe with a Peltier stack. PGE1 was injected i.v. continuously, at a dose of 0.05, 0.1 and 0.2 micrograms.kg-1.min-1. CBF tended to increase dose-dependently but not significantly by PGE1 administration. Cerebral vascular resistance was reduced significantly by every dose of PGE1 administered. Therefore, the results indicate that the cerebral vascular beds are dilated directly by PGE1. In conclusion, this study suggests that PGE1 can be used safely to control hypotension without reducing CBF during neurosurgery.

Adult↗
PubMed1989

Nerve stimulation does not necessarily enhance retrograde HRP labeling of rat motoneuron.

The retrograde horseradish peroxidase (HRP) labeling of medial gastrocnemius (MG) motoneurons was not enhanced by electrical stimulation of the sciatic nerve after HRP injection into the MG muscle of the rat. When pulse trains with short intermissions were applied immediately after the HRP injection, the number of labeled MG motoneurons on the stimulated side was even smaller than that on the control side.

Animals↗
PubMed1989

Contents of dopamine sulfoconjugate isomers and their desulfation in dog arteries.

In humans and dogs, the plasma contains little free dopamine, and dopamine is almost all present in two isomeric forms of conjugates with sulfate esters, dopamine-3-O-sulfate and dopamine 4-O-sulfate. These two isomers differ in metabolic stability and biological activity. The physiological role of dopamine sulfates is controversial. In the present study on dogs, noradrenaline, dopamine and the two dopamine sulfate isomers in the peripheral arteries were measured by high-performance liquid chromatography, and the possibility that dopamine sulfate isomers are deconjugated in the arteries as a source of free dopamine was examined. The arteries were found to contain free dopamine and dopamine 3-O-sulfate at concentrations of 0.09-0.54 and 0.008-0.015 pmol/mg wet tissue, respectively. No dopamine 4-O-sulfate was found in the arteries or the plasma. Arylsulfatase activity was assayed by incubating a crude extract of arterial homogenate with dopamine 3-O-sulfate or dopamine 4-O-sulfate and measuring the dopamine produced. Exogenous dopamine 4-O-sulfate was desulfated by the extract, but dopamine 3-O-sulfate, which is the predominant isomer in the artery, was not desulfated by the extract. These results suggest that dopamine sulfate is not converted to dopamine in physiological conditions in the dog.

Animals↗
PubMed1989

The effects of blocking nerve conduction on retrograde HRP labeling of rat motoneuron.

The effect of blocking nerve conduction on retrograde horseradish peroxidase (HRP) labeling was investigated for rat hindlimb motoneurons. Conduction of the sciatic nerve in the left leg was blocked with tetrodotoxin, and HRP solution was injected into the medial gastrocnemius (MG) muscles of both sides. The total number of labeled MG motoneurons and the labeling intensities of individual cell somas were measured. There were no differences in these two parameters between the blocked and the intact sides. The results suggest that motoneurons are sufficiently well labeled with HRP, even if they are electrically silent.

Animals↗
PubMed1989

Purification and characterization of NADPH-dependent cytosolic 3,5,3'-triiodo-L-thyronine binding protein in rat kidney.

The NADPH-dependent cytosolic 3,5,3'-triiodo-L-thyronine(T3)-binding protein (CTBP) has been purified over 30,000-fold from rat kidney by using charcoal extraction, Mono Q-Sepharose, Blue Sepharose CL-6B, and Sephacryl S-200 column chromatography. Purified CTBP had a sedimentation coefficient of 4.7 S, Stokes radius of 32.5A, and calculated molecular weight of 58,000. The apparently homogeneous protein consisted of a single polypeptide chain with Mr of 58,000 as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Scatchard analysis of T3 binding showed that NADPH increases maximal binding capacity without changes in the affinity constant (Ka = 2.43 X 10(9) M-1). Double reciprocal analysis of NADPH and binding capacity gave maximal binding capacity of 16,400 pmol/mg of CTBP, Mr = 58,000. The order of affinity of iodothyronine analogues to purified CTBP was as follows: L-T3 = D-T3 greater than triiodothyroacetic acid greater than L-thyroxine. [125I]T3 bound to purified CTBP spontaneously dissociated from CTBP at 20 degrees C (t 1/2 = 22 min) in the absence of NADPH, whereas the dissociation was not observed in the presence of NADPH. The optimal pH for T3 binding was 7.2-7.5 Na+, K+, Ca2+, and Mg2+ (0-200 mM) did not influence T3 binding to CTBP. The purified CTBP did not bind to DNA and was not adsorbed to concanavalin A-Sepharose.

Animals↗
PubMed1989

Evidence for the presence of two active forms of cytosolic 3,5,3'-triiodo-L-thyronine (T3)-binding protein (CTBP) in rat kidney. Specialized functions of two CTBPs in intracellular T3 translocation.

Cytosolic NADPH-dependent 3,5,3'-triiodo-L-thyronine (T3)-binding protein (CTBP) purified from rat kidney was further characterized in its T3 binding and its interaction with nuclei. Pretreatment of the CTBP with NADP induced dithiothreitol (DTT)-dependent T3 binding. The DTT-dependent T3 binding was increased by NADP in a concentration-dependent manner, and the maximal binding was obtained by 0.1 microM NADP. Higher concentrations of NADP (more than 0.1 microM), however, reduced T3 binding. NAD also induced DTT-dependent T3 binding, but was very low compared to that induced by NADP. NADPH and NADH did not produce DTT-dependent T3 binding. This NADP-activated, DTT-dependent T3 binding was characterized as follows: Ka for T3 binding was 1.8 x 10(9) M-1, and the maximal binding capacity was 15,000 pmol/mg of protein in the CTBP activated by 0.1 microM NADP. The molecular weight of the CTBP was 58,000 (4.7 S). A complex of [125I]T3 and CTBP (NADP.DTT.CTBP.[125I]T3), which was made from the CTBP pretreated with NADP and DTT, did not bind to DNA. However, the complex bound to the nuclei prepared from rat kidney. Treatment of the nuclei with 0.38 M KCl and with DNase I did not lead to loss of the binding activity for the complex. Treatment of nuclei with 0.5 M NaCl led to the loss of the activity for binding the complex. A complex of [125I]T3 and NADPH-activated CTBP did not bind these nuclear preparations. These results suggested that the active form of CTBP is present in two different forms: one is NADPH-activated, which plays a role as a reservoir for cytoplasmic T3, and the other is NADP-activated, which plays a role as a T3 carrier protein that transfers T3 from cytoplasm to nucleus.

Animals↗
PubMed1989

Differences in nuclear thyroid hormone receptors among species.

Hepatic nuclear thyroid hormone receptors from rat, dog, chicken, and rainbow trout were compared. Receptor affinities for 3,5,3'-triiodo-L-thyronine (T3) were similar in preparations from rat, dog, and chicken, using isolated nuclei and nuclear extracts. Rainbow trout nuclear receptor showed a lower affinity for T3. Almost half of the receptors were released into the medium with rat and chicken nuclei, and 79.7 +/- 1.1% of the receptors were released with rainbow trout nuclei, when isolated nuclei were incubated with T3 at 22 degrees for 2 hr. The affinity constant of rat liver receptor for calf thymus DNA-cellulose at 0.17 M KCl, pH 7.4, was 3.98 +/- 1.47 x 10(5) M-1, when determined using DNA-cellulose columns. The number of salt bridges involved in DNA binding of the rat receptor was 5.73 +/- 0.38. When receptor-DNA interactions were compared among species, significant differences were found, but the receptors from dog and rainbow trout liver were similar. Sephacryl S-200 column chromatography showed that chicken receptor had a Stokes radius significantly smaller than that of rat receptor. Partial proteolysis of T3-receptor complex using trypsin alpha-chymotrypsin, elastase, and papain produced distinct T3-binding fragments in different species. Our data provide evidence that nuclear thyroid hormone receptors from different species have significant structural dissimilarities.

Animals↗
PubMed1989

Antipeptide antibodies reveal structural and functional characteristics of rat placental lactogen-II.

The purpose of this investigation was to develop specific immunologic probes to rat placental lactogen-II (PL-II) and to use the immunologic probes to further characterize rat PL-II. Five oligopeptides corresponding to different regions of rat PL-II (amino acids 1-13, 56-70, 89-103, 107-118, 150-164) were chemically synthesized by solid phase methods and purified to homogeneity by reverse phase high performance liquid chromatography. The synthetic peptides were coupled to keyhole limpet hemocyanin (KLH) and the peptide-KLH conjugates were used to immunize rabbits. Antibody production was monitored by enzyme-linked immunoassay (EIA), electrophoresis and immunoblotting analyses. Each of the antipeptide antisera showed reactivity with the entire rat PL-II protein; however, the extent of the reactivities of each antiserum with rat PL-II was dependent on the conformational state of rat PL-H. Antisera directed to amino acids 56-70 showed the best reactivity toward each of the conformational states of rat PL-II tested. Antibodies generated to the entire rat PL-II protein specifically recognized the 56-70 amino acid sequence but showed limited reactivity with synthetic peptide corresponding to amino acids 1-13, 89-103, 107-118, and 150-164 of rat PL-II. Antisera to amino acids 56-70 of rat PL-II were specific for PLs as demonstrated by their recognition of rat PL-II, mouse PL-II and human PL and by their lack of reactivity with rat pituitary prolactin and growth hormone and with a series of other synthetic peptides to rat PL-II and rat prolactin-like protein-A. The immunorecognition of human PL was restricted to antipeptide antibodies directed to amino acids 56-70 of rat PL-II. The chemically synthesized peptides representing various regions of rat PL-II did not show significant interactions with prolactin receptors, and antisera directed to the peptides failed to interfere with the binding of either rat PL-II or human PL to prolactin receptors. In summary, we have generated a series of immunologic probes for studying the structure of rat PL-II. The sequence comprising amino acids 56-70 of rat PL-II was shown to make up at least part of an epitope for rat PL-II and to be a region of significant structural homology with mouse PL-II and human PL.

Amino Acid Sequence↗
PubMed1989

Age-related changes of thyroid function and immunologic abnormalities in patients with hyperthyroidism due to Graves' disease.

In order to clarify the reasons why hyperthyroidism due to Graves' disease is mild in aged patients compared to young patients, we examined the degree of hyperthyroidism and immune abnormalities in 371 untreated patients. The patients were divided into nine groups based on their age; groups A to I consisted of patients aged 0-9, 10-19, 20-29, 30-39, 40-49, 50-59, 60-69, 70-79, and 80-89 years, respectively. Serum thyroxine (T4), triiodo-thyronine (T3), and thyroglobulin levels were highest in group B (patients aged 10-19 years) and decreased progressively with advancing age. T3/T4 ratio was also highest in group B and decreased progressively with age. These data reconfirmed that the degree of hyperthyroidism is milder in older patients. The prevalence of positive microsomal and thyroglobulin antibodies was highest in group B (patients aged 10-19 years) and progressively lower in older groups, suggesting that an association with Hashimoto's thyroiditis is less prevalent in aged patients. We suggest that hyperthyroidism due to Graves' disease is mild in aged patients because responsiveness of the thyrocyte to the abnormal stimulator, thyrotropin-receptor antibody, may be reduced. Such reduced responsiveness may not be due to Hashimoto's thyroiditis, since the prevalence of antithyroid antibodies is lower in aged than in younger patients with hyperthyroidism due to Graves' disease.

Adolescent↗
PubMed1989

Changes in properties of the medial gastrocnemius motor units in aging rats.

1. The properties of motor units were investigated in the medial gastrocnemius (MG) of old rats [27.5 +/- 1.6 (SD) mo old, n = 18]. Individual motor units were functionally isolated by ventral root fiber splitting and grading stimulus intensity. The muscle-unit portion of the motor unit was identified by the glycogen depletion method. The physiological properties of 77 motor units in 6 animals and the histological results of 7 slow-twitch (type S) muscle units were compared with data from motor units in the same muscle of middle-aged rats (12.8 +/- 1.6 mo old, n = 33). 2. The motor units were classified into four types of categories [FF (fast-twitch motor units with a fatigue index less than or equal to 0.5), FI (fast-twitch motor units with a fatigue index greater than 0.5 but less than 0.75), FR (fast-twitch motor units with a fatigue index greater than or equal to 0.75), S (slow-twitch motor units with a fatigue index greater than 0.75)] using the same criteria (i.e., presence or absence of the "sag" property and fatigability) used for middle-aged rats. No significant difference in the relative distributions of these unit types was detected, although the MG muscle in old rats exhibited a relatively high proportion of type S units and fewer type FR units. 3. The mean tetanic tensions for type FF + FI and FR units were significantly smaller than those in the middle-aged rats. On the other hand, type S motor units produced more tension than in the middle-aged rats. 4. The conduction velocity of motor axons was considerably slower in any unit type of old motor units, and the most marked change was found in type FR units. 5. The general morphological features of the old rat MG were fiber-type grouping, disseminated atrophic or angulated fibers, a decrease in the total number of muscle fibers, and an increase in the number of type I muscle fibers. The major distribution patterns of fibers of different types were the same as those in the middle-aged MG. 6. Seven type S units that produced large tetanic tension were depleted of glycogen in the muscle-unit portions. These units had a large innervation ratio compared with those in the middle-aged rats, whereas the mean cross-sectional area of muscle fibers and the calculated specific tension remained unaltered.(ABSTRACT TRUNCATED AT 400 WORDS)

Aging↗
PubMed1989

Counterregulation of nuclear 3,5,3'-triiodo-L-thyronine (T3) binding by oxidized and reduced-nicotinamide adenine dinucleotide phosphates in the presence of cytosolic T3-binding protein in vitro.

The role of cytosolic T3-binding protein (CTBP) in the regulation of nuclear T3 binding was studied in vitro. Nuclear [125I]T3 binding was observed in the presence of 1.0 mM dithiothreitol (DTT). When the nuclei prepared from rat kidney were incubated with inactive form of CTBP which was also prepared from rat kidney, [125I]T3 binding to nuclei was not affected. When the nuclei were incubated with inactive form of CTBP in the presence of NADP, [125I]T3 binding to nuclei was increased, whereas binding was diminished when nuclei were incubated with CTBP in the presence of NADPH. The inactive form of CTBP was activated by NADPH. NADP also activated CTBP in the presence of DTT. Both active forms of CTBP were again inactivated by extraction with charcoal, and these inactive forms were reactivated by NADPH or by NADP and DTT, but not by NADP alone. Although the nuclei treated with 0.3 M NaCl lost the binding activity for [125I]T3 in the absence of NADP, the nuclei retained the binding activity for [125I]T3 in the presence of NADP and the inactive form of CTBP. Treatment of the nuclei with 0.5 M NaCl lost the binding activity for [125I]T3 not only in the absence but also in the presence of NADP and CTBP. These results suggested that NADP and NADPH play roles as counterregulatory factors for nuclear T3 binding in the presence of CTBP. Further, it was speculated that binding sites for the T3-CTBP complex, which is generated in the presence of NADP and DTT, are present in nuclei, and that binding sites for the complex are different from nuclear T3 receptors.

Animals↗
PubMed1989

Cytosolic 3,5,3'-triiodo-L-thyronine (T3)-binding protein (CTBP) regulation of nuclear T3 binding: evidence for the presence of T3-CTBP complex-binding sites in nuclei.

Effect of cytosolic 3,5,3'-triiodo-L-thyronine (T3)-binding protein (CTBP) on [125I]T3 binding to nuclei was investigated in vitro. CTBP and nuclei were prepared from rat kidney. CTBP was inactivated by incubating with charcoal and activated by incubating with NADPH or with NADP and dithiothreitol. Two complexes of CTBP and T3 [CTBP-T3(NADPH) and CTBP-T3(NADP)] were separately prepared, and the functions of these complexes were estimated. [125I]T3 binding to nuclei was not influenced by the inactive form of CTBP. NADP or NADPH alone did not modify [125I]T3 binding to the nuclei. However, the binding was markedly inhibited by NADPH in the presence of the inactive form of CTBP, but it was not inhibited by NADP in the presence of the inactive form of CTBP. The ability of nuclei to bind [125I]T3 was markedly diminished by pretreatment of the nuclei with 10(-8) M unlabeled T3. The diminished activity was not modified by adding NADPH or NADP. However, [125I]T3 bound to these nuclei in the presence of NADP and the inactive form of CTBP. Binding of [125I]T3 to these nuclei was not observed in the presence of NADPH and the inactive form of CTBP. When the nuclei that had previously been saturated with 10(-6) M unlabeled T3 were incubated with [125I]T3-CTBP(NADP) complex, radioactivity bound to the nuclei. The binding of radioactivity, however, was not observed when these nuclei were incubated with [125I]T3. The [125I]T3-CTBP(NADPH) complex did not bind to these nuclei. When the nuclei that had previously been treated with T3-CTBP(NADP) complex were incubated with [125I]T3, radioactivity bound to the nuclei. The binding of radioactivity, however, was not observed when these nuclei were incubated with [125I] T3-CTBP(NADP) complex. The [125I]T3-CTBP(NADPH) complex did not bind to these nuclei. These results suggested that 1) CTBP activated by NADP plays a role as a carrier protein for T3 from cytoplasm to nucleus; 2) there are binding sites for T3-CTBP(NADP) complex in rat kidney nuclei; and 3) these binding sites are different from nuclear T3 receptors.

Animals↗
PubMed1989

Synthesis of myo-inositol derivatives required for the total synthesis of surugatoxin, prosurugatoxin, and neosurugatoxin.

Two myo-inositol derivatives (4) and (5), required for the total synthesis of surugatoxin, prosurugatoxin, and neosurugatoxin, were prepared. Synthesis of (+/-)-2,3-O-cyclohexylidene-4,5-O-isopropylidene-1-O-methoxymethyl-myo-i nositol (4) was achieved from (+/-)-1-O-benzoyl-2,3-O-cyclohexylidene-4,5-O-isopropylidene-myo-inosito l (6) in 4 steps, and (-)-2,3-O-cyclohexylidene-1,4-di-O-methoxymethyl-5-O-[2',3',4'-tri-O-ace tyl- beta-D-xylopyranosyl]-myo-inositol (5) was synthesized from (+/-)-1-O-benzoyl-2,3-O-cyclohexylidene-5,6-O-isopropylidene-myo-inosito l (12) in 7 steps.

Chemical Phenomena↗
PubMed1989

Effect of atrial natriuretic peptide on catecholamine release from human pheochromocytoma.

The effect of synthetic alpha human atrial natriuretic peptide on catecholamine release from human pheochromocytomas was studied both in vivo and in vitro. Iv infusion of atrial natriuretic peptide at a rate of 0.1 microgram.kg-1.min-1 for 60 min into two normotensive patients with pheochromocytoma caused a small decrease in the mean blood pressure, increase in the heart rate, and marked increase in the plasma level of norepinephrine (2.08 to 6.83 nmol/l, and 1.15 to 2.83 nmol/l, respectively) compared with 0.60 +/- 0.10 to 1.19 +/- 0.20 nmol/l in normal subjects. Treatment with atrial natriuretic peptide also increased the plasma epinephrine level from 0.34 to 1.27 nmol/l, and from 0.67 to 0.79 nmol/l in the patients with pheochromocytoma, but not in the normal subjects (0.05 +/- 0.01 to 0.05 +/- 0.01 nmol/l). After removal of the tumour, the responses of the plasma norepinephrine and epinephrine to atrial natriuretic peptide infusion were normalized. There was no significant effect of 10(-8) to 10(-5) mol/l atrial natriuretic peptide on the basal release of catecholamines from isolated superfused pheochromocytoma tissue. Atrial natriuretic peptide (10(-7) mol/l) did not affect the increase in catecholamine release induced by glucagon (10(-5) mol/l). These results suggest that the exaggerated responses of plasma catecholamines to atrial natriuretic peptide in patients with pheochromocytoma may be due to a washout effect resulting from change in blood flow in the vessels feeding the tumour rather than increased sympathetic nerve activity induced by hypotension and hypovolemia. The results also suggest that atrial natriuretic peptide dose not have any direct action on pheochromocytoma tissue causing catecholamine release.

Adrenal Gland Neoplasms↗
PubMed1989

Stabilization, accurate determination, and purification of rat liver nuclear thyroid hormone receptor.

Rat liver nuclear thyroid hormone receptor lost 3.5.3'-tri-iodo-L-thyronine (T3)-binding activity with a half-life of 14 days, 4h, 139 min, 62 min, 16 min or 6 min at 0, 36, 38, 40, 43 or 45 degrees C respectively, when present in crude nuclear extracts. Glycerol increased the half-life of the receptor during heat inactivation. Protection was reversible by removing the glycerol. The receptor was unstable at a pH below 6.0 or above 10.0. We also found a loss of the receptor activity during the separation of bound and free hormone using the resin test. Of several conditions tested for the separation of bound and free hormone, the addition of heated nuclear extract gave the most accurate estimation of bound hormone when using the resin test. Using these characteristics of the receptor, we purified the receptor to 1220 pmol T3-binding capacity/mg protein with a final yield of 14.6 micrograms/4 kg rat liver.

Animals↗
PubMed1989

Possible role of histones in the organization of rat liver thyroid hormone receptors in chromatin.

The effects of histone subfractions on rat liver thyroid hormone receptor-DNA interaction were examined using an in-vitro DNA-cellulose binding assay. H1 histones bound to DNA showed reversible and potent inhibition of receptor-DNA binding without affecting receptor hormone binding. Poly-lysine, bovine serum albumin, ovalbumin and cytochrome c did not alter receptor-DNA binding. H1 histone subfractions (calf thymus lysine-rich histone (CTL)-1, CTL-2 and CTL-3) showed potent inhibition of receptor-DNA binding indistinguishable from each other. The quantity of H1 histone subfractions bound to DNA was the same. Although each subfraction has different functional properties, inhibition of receptor-DNA binding was a common feature of all the H1 histone subfractions, which is important for the non-random distribution of the receptor in chromatin. Binding of the receptor to core histones was investigated; it was found to bind to core histones more potently than to other proteins (H1 histone, ovalbumin and cytochrome c). Among core histone subfractions, H4 histone bound to the receptor most potently and is the candidate to be one of the acceptor sites of the receptor in chromatin.

Animals↗