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Biomedical subjects

T Shibasaki

Publications and source records attributed to T Shibasaki.

At least 271 records · Page 15Linked to original sources
PubMed1980

High-molecular-weight immunoreactive beta-endorphin in extracts of human placenta is a fragment of immunoglobulin G.

A high-molecular-weight protein with beta-endorphin- and adrenocorticotropin-immunoreactivities was isolated from extracts of human placenta after several purification steps, including immunoadsorption with a well-characterized antiserum raised to beta-endorphin. This protein was identified as the heavy chain of the human immunoglobulin class IgG1. These results have led to the recognition of homologies in the amino acid sequences of these physiologically unrelated molecules. They also suggest caution in accepting immunological competence as the sole criterion of the chemical identity of a ligand.

Amino Acid Sequence↗
PubMed1980

Stress-induced release of prolactin: blockade by dexamethasone and naloxone may indicate beta-endorphin mediation.

Basal levels of immunoreactive (ir) beta-endorphin, corticotropin (ACTH), and prolactin (PRL) in plasma of male rats decrease after dexamethasone pretreatment (400 microgram/kg at 24 hr and 200 microgram/kg at 2 hr before). Inescapable electric footshocks increase ir-beta-endorphin, ACTH, and PRL plasma levels and this effect is blocked by dexamethasone pretreatment. Morphine (20 mg/kg) also increases ir-beta-endorphin, ACTH, and PRL levels. Dexamethasone pretreatment blocks the morphine-induced release of ir-beta-endorphin but does not prevent the morphine-induced release of PRL. Naloxone, the opiate antagonist, decreases basal plasma levels of PRL and partially blocks the stress-induced increase of PRL, but it has no effect on the basal or stress-induced release of ir-beta-endorphin. These results are consistent with the proposal that beta-endorphin may interact with an opiate receptor involved in the regulation of PRL secretion.

Adrenocorticotropic Hormone↗
PubMed1979

Opioid peptides and alpha-melanocyte-stimulating hormone in genetically obese (ob/ob) mice during development.

Compared to littermate controls (C57BL/6J ob/?), body weights of genetically obese (ob/ob) mice are significantly higher at 1-6 months of age; the greatest percentage weight gain of the ob/ob group occurs during the first 3 months of life. Levels of pituitary immunoreactive beta-endorphin and immunoreactive alpha-melanocyte-stimulating hormone are also significantly elevated in ob/ob animals compared to controls. However, these pharmacological differences only emerge at 4-6 months of age--3 months after the appearance of obesity. High levels of immunoreactive endorphin in the pituitary are, therefore, more likely to be a consequence than a cause of obesity. Furthermore, numerous other neurologic abnormalities, which may or may not play a role in the obesity syndrome, are evident in ob/ob mice. Compared to controls, ob/ob total brain, hypothalamus, and pituitary weights are 11%, 16%, and 23% less, respectively. Levels of immunoreactive Leu5-enkephalin in pars nervous are also 200% higher in ob/ob mice; this increase is apparent at 1-6 months of age and is highly correlated with changes in body weight.

Aging↗
PubMed1979

Composition of free amino acids in brain tumors.

The composition of the free amino acid pools in various brain tumors and in normal brains obtained at surgery or at autopsy is determined with an automatic amino acid analyzer and the results statistically evaluated. The tumors have lower ratios of GABA in the pools than the normal brain; tumors with higher GABA ratios are found in those which are in close contact with and have an invasive nature to brain tissue. In gliomas, the more malignant a tumor becomes, the more different the composition in that tumor is from that in normal brain tissue. But conversely, the ratio of GABA is highest in glioblastoma. The composition of the pool in oligodendroglioma is not significantly different from that in the normal brain. Metastatic brain tumors show the highest ratios of phenylalanine, tyrosine and methionine in the pool among the tumors and the normal brain. From the viewpoint of the composition of the free amino acid pools, like from that of the histological aspects, brain tumors seem to be classified into four groups: glioma, neurinoma, meningioma and metastatic tumors.

Adolescent↗
PubMed1977

[Extraneural metastases of malignant brain tumors through ventriculoperitoneal shunt--report of two autopsy cases and a review of the literature (author's transl)].

Internal drainage of cerebrospinal fluid utilizing a mechanical tube has been an increasingly common and effective procedure for the relief of non-communicating hydrocephalus with intracranial tumor. However, several cases have recently been reported in which extraneural metastases of the tumor were initiated through the shunt tube implanted. The purpose of this paper is to present two cases with malignant brain tumor metastasizing extraneurally through ventriculoperitoneal shunt, and to review the reported cases in the literature. Case 1 The patient, a 9-year-old boy, had been suffering from headache and vomiting for 3 months prior to admission to the Neurosurgical Clinic, Gumma University Hospital. On admission, he had choked discs and cerebellar dysfunction with a staggering gait. The clinical diagnosis was a 4th ventricle tumor. On November 29, 1971, a suboccipital craniectomy was performed. A medullary tumor in the 4th ventricle was partially removed, and ventriculoperitoneal shunt was also performed. Subsequently postoperative irradiation was given, and the symptoms were abated. Histological diagnosis was ependymoblastoma. Thirteen months later, he was again admitted because of visual disturbance, psychic change and pituitary hypofunction. Bilateral frontal craniotomy revealed a large mass over the midline of the anterior skull base, accompanied by numerous meningeal neoplastic deposits. The tumor was partially removed and histologically proven to be meningeal metastases of ependymoblastoma. Irradiation was again given and the symptoms improved. But the 4th ventricle tumor recurred 5 months after the 2nd operation, and then a massive intraperitoneal effusion appeared. Cytological examination revealed clusters of tumor cells in the ascites. The patient died on September 8, 1974, namely 22 months after the ventriculoperitoneal shunt was implanted. Postmortem examination showed a solid tumor in the 4th ventricle which was accompanied by diffuse meningeal dissemination, and metastases were present throughout the peritoneal surface...

Adult↗
PubMedDate not supplied

Effect of polyaspartic acid on CdCl2-induced nephrotoxicity in the rat.

We produced an animal model of CdCl2 nephrotoxicity in rats, and treated them with polyaspartic acid (PAA) to prevent renal damage. Male Sprague-Dawley (SD) rats (190-200 g) were used to induce proximal renal tubular damage by daily injection of CdCl2 3.0 mg/1,000 g body wt for 2 wk. CdCl2-exposed SD rats exhibited significant increases in urine volume, urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG), alanine aminopeptidase (AAP), and fractional excretion of sodium (FENa) and a decrease in the percentage of tubular reabsorption of phosphate (%TRP). Of these indicators of proximal tubular function, AAP and %TRP are more sensitive than NAG or FENa. No glycosuria or aminoaciduria, however, were observed. PAA markedly improved these indicators of proximal tubular function. Daily urinary protein excretion and creatinine clearance, on the other hand, did not change after administration of PAA. Cd concentrations in the cortex were 3 times higher than in the medulla, however, there were no differences between Cd-treated rats and PAA-treated rats. Our animal model is an excellent one for determining the effect of cadmium on renal proximal tubule damage. PAA appears to be useful in the treatment of CdCl2 nephrotoxicity.

Acetylglucosaminidase↗
PubMedDate not supplied

Hyperthermic action of somatostatin-28.

An intracisternal injection of somatostatin-28 produced hyperthermia in rats at cold, thermoneutral, warm ambient temperatures. The hyperthermic response to somatostatin-28 was not prevented by pretreatment of rats with the following agents: alpha-methylparatyrosine, phenoxybenzamine, propranolol, sulpiride, atropine, methysergide or naloxone. Somatostatin-28 prevented hypothermia induced by bombesin and gamma-MSH when it was administered simultaneously, but it left the hyperthermic response to TRH intact. The results indicate that somatostatin-28 produces hyperthermia by elevating a "set point" or regulated level of temperature. Under the conditions tested, the hyperthermic response to somatostatin-28 does not appear to be dependent on muscarinic cholinergic, serotonergic, alpha- or beta-adrenergic, dopaminergic or endogenous opiate system.

Animals↗
PubMedDate not supplied

The distribution of alpha-melanocyte stimulating hormone (alpha-MSH) in the central nervous system of the rat: an immunohistochemical study. II. Lower brain stem.

The distribution of immunoreactive alpha-melanocyte stimulating hormone (alpha-MSHI) in the rat lower brain stem was examined by indirect immunofluorescence or peroxidase- anti-peroxidase immunohistochemical method using an antiserum against synthetic alpha-MSH. The results confirmed the presence of alpha-MSHI fibers in the midbrain central gray matter and parabrachial area, and demonstrated a much more extensive distribution of these fibers in various parts of the lower brain stem areas previously thought not contain alpha-MSHI fibers. In addition, the commissural nucleus was identified as a new alpha-MSHI neurons-containing site. No alpha-MSHI neurons were seen in other regions of the rat lower brain stem.

Animals↗
PubMedDate not supplied

Intracellular Na+ activates a K+ channel in mammalian cardiac cells.

In a wide variety of cells, various intracellular agents, such as Ca2+, ATP and cyclic nucleotides, regulate ionic conductances of the membrane. In cardiac cells, the intracellular Na+ concentration [( Na+]i) frequently increases when a disturbance occurs in the electrogenic Na-K pump activity or the Na-Ca exchange mechanism. We have investigated a possible role of [Na+]i in controlling ion channels by using a patch-clamp method, and have found a K+ channel that is gated by [Na+]i greater than 20 mM, but not by the intracellular Ca2+ concentration (approximately 10(-4) M). We report here that the channel has a unitary conductance of 207 +/- 19 pS (n = 16) with K+ concentrations of 150 mM outside and 49 mM inside, and shows no detectable voltage-dependent kinetics. The Na+-activated K+ channel represents a novel class of ionic channel.

Adenosine Triphosphate↗
PubMedDate not supplied

Effect of testosterone replacement therapy on serum PSA in patients with Klinefelter syndrome.

The effect of testosterone replacement therapy on serum prostate-specific antigen (PSA) was investigated in 11 patients with Klinefelter syndrome. Significant increases in serum testosterone level and prostate volume were observed after testosterone replacement therapy. However, serum PSA level did not change after testosterone replacement therapy. It would appear that serum PSA is not influenced by exogenous testosterone in patients with Klinefelter syndrome.

Adult↗
PubMedDate not supplied

Correlation between the neural noise in the thalamus after cerebrovascular disease and computerized tomography. A case report.

The case is presented of a 45-year-old man who suffered from a sudden attack of unconsciousness with right hemiplegia and later developed a spastic hemiparesis accompanied by involuntary movement of the right upper limb. CT scan revealed an old putaminal hemorrhage and almost intact thalamus, but neural noise recordings during the stereotactic thalamotomy of this case showed marked decrease of the neural activity in the thalamus suggesting some functional changes.

Cerebral Hemorrhage↗
PubMedDate not supplied

Effect of cyclophosphamide pulse therapy in a patient with intractable lupus nephritis.

A 32-year-old female was suffering from intractable lupus nephritis (LN). Prednisolone at 30 mg per day had been prescribed for two months because of massive proteinuria and edema. After that, anasarca and orthopnea were induced, and hypoproteinemia, hypercholesteremia, and anti-cardiolipin antibody were observed. Prednisolone at a dose of 60 mg per day was necessary. However, there was no improvement of the nephrotic state and renal pathological changes shown as diffuse proliferative lupus nephritis were followed by moderate crescent formation as determined by serial needle biopsy. Cyclophosphamide (CYP) pulse therapy was started and marked improvement of LN was obtained clinically and serologically without significant adverse effects.

Adult↗