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Biomedical subjects

K Takano

Publications and source records attributed to K Takano.

At least 253 records · Page 14Linked to original sources
PubMed1994

Effects of activin A on ionic channels in human FSH-secreting tumour cells.

1. Effects of activin A on ionic channels were examined in human FSH-secreting tumour cells using electrophysiological techniques. 2. Under voltage clamp with the conventional whole-cell clamp technique, the voltage-gated Na+ channel, the T- and L-type Ca2+ channels, the delayed K+ channel and the A-channel were observed. 3. With the nystatin-perforated whole-cell clamp technique, the same voltage-gated channels were recorded. Activin A (10(-7) M) increased the amplitude of the L-type Ca2+ current, whereas it decreased the amplitude of the delayed K+ current. 4. Under current clamp with the perforated whole-cell clamp technique, more than 80% of the cells exhibited spontaneous action potentials. Application of 10(-7) M activin A depolarized the membrane with a conductance increase and augmented action potential frequency. The reversal potential of the activin A-induced current was -20 to 0 mV. The activin A-induced current was abolished in a Na(+)-free extracellular solution, indicating that the membrane depolarization caused by activin A was due to the conductance increase to Na+ ions through non-selective cation channels.

Activins↗
PubMed1994

Effect of growth hormone on wound healing in protein-malnourished rats treated with corticosteroids.

This study was designed to evaluate the efficacy of human growth hormone (GH) in improving the tensile strength of wounds weakened by chronic protein malnourishment and corticosteroid (CS) administration. Eighty-six female Sprague-Dawley rats, weighing 80 to 100 g, were divided into five groups. Group 1 (control) received 23.4% protein chow for 8 weeks before surgery. Groups 2, 3, 4, and 5 received nonprotein chow on alternate days for the same duration. Groups 3 and 5 received prednisolone (2 mg/kg/d intramuscularly) for 3 weeks preoperatively and for 5 days postoperatively. Groups 4 and 5 were given GH (somatotropin, 1 IU/d) for 5 days postoperatively. All the animals underwent a precise 4-cm midline celiotomy. Wound testing was performed on the sixth postoperative day, after removal of the sutures. The bursting strength (BS, mean +/- SD) for group 1 was 145 +/- 16 mm Hg. The BS for groups 4 (137 +/- 13 mm Hg) and 5 (134 +/- 7 mm Hg) were significantly stronger than those for groups 2 (115 +/- 15 mm Hg) and 3 (91 +/- 16 mm Hg). The authors conclude that postoperative systemic GH restored the wound BS in protein-malnourished animals treated with CS, to the level of the normally nourished controls.

Alanine Transaminase↗
PubMed1994

Characterization of phe B gene encoding catechol 2,3-dioxygenase.

DNA sequence of the phe B gene isolated from a chromosome of the phenol degrading bacterium Pseudomonas putida BH is identical to that of the dmp B gene from the phenol degradative plasmid, pVI150. Catechol 2,3-dioxygenase encoded by phe B showed similar substrate specificity to that of xyl E. However, Phe B has much smaller Km values than Xyl E, indicating that Phe B is useful for treatment of low concentrations of catechol derivatives in waste water.

Biodegradation, Environmental↗
PubMed1994

Psychosocial adjustment in a large cohort of adults with growth hormone deficiency treated with growth hormone in childhood: summary of a questionnaire survey. Committee for the Study Group of Adult GH Deficiency.

The quality of life of adult patients with growth hormone (GH) deficiency, who ceased GH therapy before the age of 20 years, was surveyed. Questionnaires were sent to 1116 patients and their physicians, asking about socioeconomic status and for medical information, respectively. Response rates were 64% and 69%, respectively. The final height of the patients was about -2 SD in 61% of those surveyed. The distributions of occupation and income were similar to those in the general population. Patients with a final adult height below 155 cm (men) and below 140 cm (women) felt disadvantaged in terms of obtaining employment and finding partners. Slight psychological problems in these patients were revealed by the Cornell Medical Index health questionnaire.

Adult↗
PubMed1994

Activation of G protein-coupled K+ channels by dopamine in human GH-producing cells.

Dopamine (DA) inhibited the secretion of growth hormone (GH) from cultured human GH-secreting adenoma cells. The mechanism of this DA effect on these cultured cells was investigated with electrophysiological techniques. Under current clamp, DA (10(-6) M) hyperpolarized the membrane and arrested Ca(2+)-dependent action potentials. Voltage clamp experiments revealed that this membrane hyperpolarization was the result of a K+ conductance increase caused by DA. The current-voltage relationship of the DA-induced K+ current showed an inward-going rectification. Application of sulpiride (10(-6) M) abolished the DA-induced K+ current, indicating that the hyperpolarization was caused by the activation of D2-like receptors. Pertussis toxin (PTX) treatment eliminated the DA-induced K+ current as well as the DA-induced inhibition of GH secretion. An intracellular application of guanosine-5'-O-(3-thiotriphosphate) (100 microM) evoked a spontaneous increase in the K+ current in the absence of an agonist, and the application of DA did not further increase conductance. Intracellular application of guanosine-5'-O-(2-thiodiphosphate) (2 mM) inhibited the DA-induced K+ current. These results indicate that the DA-induced K+ channel is coupled to a G protein. When adenosine 3',5'-cyclic monophosphate (cAMP, 100 microM) was added to the patch-pipette solution, the DA-induced K+ current was still observed, indicating that the DA-induced K+ current was not caused by an inhibition of cAMP production.(ABSTRACT TRUNCATED AT 250 WORDS)

Dopamine↗
PubMed1994

Induction of drug metabolizing enzymes by polychlorinated biphenyl in the parotid gland and relation to changes in vitamin A content and morphological changes.

The relationship between the morphological changes and vitamin A content during the development of acute toxicity induced by polychlorinated biphenyl (PCB) in mouse parotid glands was investigated. PCB was administered intraperitoneally at a single dose of 2 mg/kg. Ultrastructural studies revealed remarkable morphological changes in the rough endoplasmic reticulum, nucleus, Golgi apparatus and the secretory granules at 7 days after the administration of PCB. The activities of adenosine monophosphatase (AMPase) and alkaline phosphatase were increased 1 day after PCB administration. Then the activity of NADPH-cytochrome c reductase increased 4 days after PCB administration. Subsequently, the vitamin A content of the parotid glands significantly decreased at 7 days compared with the control. These sequential changes in enzyme activities implied that the decrease of vitamin A content in the parotid glands may be partly due to catabolism of vitamin A by increased activities of microsomal enzymes induced by PCB. In conclusion, it is suggested that PCB also induces drug metabolizing enzymes in the parotid gland cells and that the acute toxicity of PCB on this tissue may occur, at least partly, through the reduction of vitamin A not only by the secondary effect from liver impairment but also by the locally accelerated catabolism of vitamin A in the mouse parotid gland.

Animals↗
PubMed1994

Octreotide treatment results in the inhibition of GH gene expression in the adenoma of the patients with acromegaly.

Seven patients with growth hormone (GH)-secreting pituitary adenoma were treated preoperatively with octreotide (Sandostatin or SMS 201-995; a somatostatin analogue), and were compared with 18 non-treated patients in their clinical courses and adenoma analyses. Octreotide treatment improved the endocrinological data in all 7 cases. The octreotide-treated adenomas were soft and easily removed by suction and curettage. The postoperative normalization of endocrinological data was encountered more often in the octreotide-treated cases than in the non-treated, although the statistical significance was not observed by the limited number of cases. The adenoma tissues were examined with conventional histology and immunohistochemistry, and the amount of GH messenger ribonucleic acid (mRNA) was quantitatively assessed. The studies demonstrated: 1) No fibrosis nor necrosis was observed in the adenomas from the octreotide-treated patients. 2) Immunohistochemistry for human GH revealed no remarkable differences between the octreotide-treated and the non-treated adenomas. 3) The amounts of GH mRNA in the adenoma from the octreotide-treated patients were 4.2 +/- 1.8 (mean +/- SEM; expressed in an arbitrary unit) and were significantly less than those from the non-treated (33.6 +/- 9.1). These data suggest that octreotide inhibits not only GH release from the adenoma but also its biosynthesis.

Acromegaly↗
PubMed1994

A case of a primary hepatic tumor causing segmental changes on imaging and its relation to Zahn's infarct.

A 69-year-old female was admitted to our hospital for further examination of an intrahepatic mass which had been found while undergoing a complete physical examination. The mass measured 4 cm in size and was located in the medial segment (S4) of the liver. On computed tomography (CT), S4 was observed to be 'atrophied' and was well enhanced segmentally. A celiac angiogram showed segmental staining, and a transarterial portogram demonstrated portal stoppage of S4 from the left branch. However, no segmental intensity difference was seen on magnetic resonance imaging (MRI). An aspiration biopsy showed adenocarcinoma and thus an operation was performed under a tentative diagnosis of intrahepatic cholangiocarcinoma. The postoperative diagnosis of the tumor was combined hepatocellular and cholangiocellular carcinoma. However, no histological abnormality was seen in S4, contrary to the expectation of Zahn's infarct. In this study, we discuss the mechanism and imaging findings of Zahn's infarct, the possible reasons as to why no pathological change was seen in S4, as well as stress the rarity of reports on Zahn's infarct in cases of portal thrombus due to hepatocellular carcinoma.

Aged↗
PubMed1994

[Cesium-137 residues in food and in persons in areas severely contaminated by the Chernobyl power station accident].

On April 26, 1986, the fourth reactor of the Chernobyl Nuclear Power Station, in the Ukraine, of the former Soviet Union, exploded. Since March in 1991, a group including the author has been performed medical surveys and provided assistance centered mainly in Gomel district of the Republic of Belarus, which contains many severely contaminated areas due to fallout. Ultra sound scanning was performed by the Shinshu University School of Medicine Second Department of surgery on thyroid glands of children in Chechersk region, of Gomel. Twenty-one persons, each with tuberculous echogenic dots in their thyroid glands, were brought to Japan for further examination. The 137Cs residue was measured in these 21 persons, using a whole-body counter (WBC). Subsequently 137Cs was also measured in a range of food items found in the city in which they live. These studies indicate that, although the children live in the same area, differences in life style and in food intake are reflected in the amount of cesium residue in their bodies.

Adolescent↗
PubMed1993

Muscle pH/PCO2 monitoring.

The surface pH of skeletal muscle has been confirmed to be a sensitive indicator of peripheral muscle blood flow, but the development of a better electrode has been required. As a consequence, a unique and minute sensor was developed to measure muscle pH/PCO2. The purpose of this article was to evaluate this new monitoring device experimentally and clinically in order to clarify its effects, usefulness and specificity. Our experimental and clinical results showed that placement and measurements using the muscle pH/PCO2 monitor were easily and quickly accomplished without any complications. This small sensor provided an accurate assessment of vital physiologic functions and gave an early warning of clinical deterioration. The new monitor should be useful in pediatric surgery clinical management.

Animals↗
PubMed1993

Growth hormone treatment in Turner syndrome: results of a multicentre study in Japan. The Committee for the Treatment of Turner Syndrome.

Patients with Turner syndrome were treated with recombinant human growth hormone (GH) for 3 years. Sixty-eight patients received GH, 0.5 IU/kg/week, while 93 received GH, 1.0 IU/kg/week, by daily subcutaneous injection. Both treatment groups showed a statistically significant increase in growth during treatment. However, the higher dose increased height velocity to a significantly greater extent during the first and second year of treatment. The projected adult height was exceeded by 52 of 71 patients over the age of 14 years. Plasma insulin-like growth factor 1 levels were elevated and no remarkable advances in bone age were observed. There were no other significant changes in physical or laboratory parameters. No glucose intolerance was observed. These results indicate that GH treatment is useful for accelerating growth velocity in patients with Turner syndrome. However, further study will be required to find the most appropriate dose.

Adolescent↗
PubMed1993

Altered cerebral hemodynamics and metabolism in Takayasu's arteritis with neurological deficits.

BACKGROUND AND PURPOSE: Takayasu's arteritis is a nonspecific arteritis involving major cerebral arteries. The aim of our study is to examine cerebral hemodynamics and metabolism in Takayasu's arteritis with neurologic symptoms. METHODS: We measured cerebral blood flow and metabolism using positron emission tomography in seven patients (14 to 59 years of age) with Takayasu's arteritis who developed transient ischemic attacks (2 patients), ischemic stroke (4) or putaminal hemorrhage with multiple brain infarction (1). RESULTS: All patients had severe stenosis or occlusion of one or more major cerebral arteries. There were no significant differences in the values of cerebral blood flow, oxygen extraction fraction, and cerebral blood volume in the infarcted and noninfarcted hemisphere. By contrast, the value of cerebral metabolic rate for oxygen in the infarcted hemisphere was markedly reduced (1.87 mL/100 mL per minute, P < .01) compared with controls. Mean transit time in the infarcted hemisphere was significantly greater than in the noninfarcted one, both in patients and controls (P < .01 and P < .05, respectively). CONCLUSIONS: Collateral blood flow to the hemisphere without brain damage may be relatively well developed in Takayasu's arteritis, although hemodynamic reserve as well as oxygen metabolism were impaired in the infarcted hemisphere with ischemic lesions.

Adolescent↗
PubMed1993

Idiopathic cerebral hemorrhage during delivery in normotensive women--case reports.

Two normotensive pregnant women who developed cerebral hemorrhage during delivery are reported. The hematoma was small and subcortical in one and large and putaminal in the other. They had no history of hypertension, cerebrovascular disorders, or eclampsia. Cerebral angiography studied in one case revealed no abnormalities. Idiopathic cerebral hemorrhage during delivery without any evidence of vascular risk factors is discussed.

Adult↗
PubMed1993

Localization of salivary proteins in granules of human parotid and submandibular acinar cells.

Electron microscopic immunocytochemistry was used to investigate the distribution of four secretory proteins within the granules of human parotid and submandibular gland acinar cells. The results demonstrate that the distribution of the individual proteins differs significantly. Amylase is concentrated within the electron-dense regions of the granules, whereas agglutinin is present mainly in the regions of lower density. In contrast, the proline-rich proteins and histatins are distributed throughout the content of the granules and do not appear to be concentrated in either the high- or low-density regions. The results also suggest that different mechanisms, such as self-aggregation or ionic complexes with metal ions and charged macromolecules, may be involved in the packaging of individual proteins within the same granule. Further, they also show that among the salivary glands of various species, the intragranular distribution of similar proteins (e.g., amylase and proline-rich proteins) may differ.

Agglutinins↗
PubMed1993

Characterization of new monoclonal antibodies to human insulin-like growth factor-II and their application in western immunoblot analysis.

Four immunoglobulin G1 class monoclonal antibodies (mAbs; 1D5, 1D9, 2B11, and 2H11) were produced against recombinant human insulin-like growth factor-II (rhIGF-II). Enzyme-linked immunosorbent assay established that these four mAbs specifically recognized rhIGF-II and hIGF-II, but not rhIGF-I. mAbs 1D5, 1D9, and 2H11 did not cross-react with mouse rIGF-II, although there are only six amino acid differences between mouse IGF-II and human IGF-II. The epitope for each mAb was partially defined by enzyme-linked immunosorbent assay using mouse-human chimera IGF-II mutants and other IGF-II mutants that were prepared by site-directed mutagenic procedures. These results indicated that the epitopes of mAbs 1D5, 1D9, and 2H11 are in the C-domain of hIGF-II around Ala32 to Ser36, and that of 2B11 is in the carboxyl-terminal end of the B- and A-domains of hIGF-II. A specific and sensitive RIA was developed using mAb 2H11. In this RIA, IGF-II variant ([RLPG/S29]IGF-II) and rhIGF-II competed equally with [125I]IGF-II for binding to mAb 2H11. Similar results were produced when mAbs 1D5, 1D9, and 2B11 substituted for 2H11. The potential usefulness of mAb 2H11 in an immunoblot procedure to characterize the heterogeneity of IGF-II in the sera and tumor tissues of patients with nonislet cell tumor hypoglycemia was evaluated. A procedure that combined acid-ethanol extraction of serum or tumor tissues and immunoaffinity concentration of the extracted IGF-II with mAb 2H11-immobilized resin was found to be an effective way to prepare the samples. In Western immunoblots, a quantity of rhIGF-II as low as 3 ng could be identified, whereas 200 ng rhIGF-I or rat IGF-II were not recognized. The levels of IGF-II in the sera of 12 patients with nonislet cell tumor hypoglycemia varied from normal to about twice normal. The mol wt (M(r)) of this IGF-II was between 10-17K. There was little of the processed 7.5K M(r) IGF-II in the sera of these patients. Finally, the source of the high M(r) forms of IGF-II was the tumor, because the ratios of high M(r) forms of IGF-II to 7.5K IGF-II changed dramatically from 99:1 and 91:9 to 4:96 and 32:68 in two patients after successful excision of their tumors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗