Biomedical subjects

M Sakaue

Publications and source records attributed to M Sakaue.

At least 55 records · Page 3Linked to original sources

PubMed1994

Nutrient-induced thermogenesis (NIT) following amino acid infusion.

Nutrient-induced thermogenesis (NIT) induced by parenteral infusion of amino acid (AA) mixtures of different composition and of the same AA mixtures given via different routes (parenteral or intraportal infusion) were investigated in rats using a small animal indirect calorimeter. When 8 different AA solutions of differing composition but with the same total concentration were infused parenterally, both standard NIT (each AA is assumed to generate 3.28 kcal/g) and specific NIT (heat energy of each AA is calculated assuming that it is oxidized to carbon dioxide and water, and metabolised to urea and sulphuric acid) values of the leucine (Leu)-rich and the glycine (Gly)-rich solutions were significantly greater than those of the control solution. Removal of Leu or Gly from the respective AA solutions reversed the increase of both NIT values down to control levels. When the parenteral and portal infusion routes were used in one rat, both NIT values for parenteral infusion of the Leu-rich solution were again significantly greater than those of the control. Likewise, both NIT values for intrportal infusion of the Leu-rich solution were also significantly greater than those of the control. However, no difference in NIT values was found between parenteral and portal infusion of either solution. The result of this study indicated that Leu and Gly may be thermogenic AAs, and the thermogenic effect of Leu is not dependent upon the route of infusion.

Journal Article↗

PubMed1994

Enhanced transcription of the human alpha 2A-adrenergic receptor gene by cAMP: evidence for multiple cAMP responsive sequences in the promoter region of this gene.

Expression of the human alpha 2A-adrenergic receptor gene is induced by cAMP. The present studies were designed to define potential cAMP-responsive enhancer elements (CREs) in the promoter region of this gene. Regions from the 5'-flanking sequences of the gene were placed in a promoterless vector with a chloramphenicol acetyltransferase (CAT) reporter gene, and cAMP-stimulated CAT activity was assayed in transfected JEG-3 placental carcinoma cells. Enhancer activity responsive to cAMP was located in DNA sequences both upstream and downstream from the endogenous promoter region. Within the upstream sequences there is a putative "core sequence" homologous to the eight base CRE consensus palindrome, but this region did not function independently as a CRE enhancer; additional upstream sequences were required to provide significant enhancer activity in response to cAMP. Regulation of expression of the alpha 2A-adrenergic gene by cAMP is complex and involves multiple and likely novel DNA sequences.

Base Sequence↗

PubMed1994

[Prostatic carcinoma with bilateral testicular metastasis: a case report].

A 77-year-old man was referred for the treatment of urolithiasis. The patient noticed the swelling of bilateral scrotal contents 2 weeks previously and had been suffering from bladder symptoms for several years, dysuria and pollakisuria. Therefore, he was admitted for the treatment of stones and further examination. By transrectal examination, prostatic carcinoma was suspected. Biopsy of the prostate and bilateral orchiectomy revealed the prostatic carcinoma and the metastatic adenocarcinoma of the bilateral testis. The histological or immunohistological examination indicated that the metastatic adenocarcinoma was prostate in origin.

Adenocarcinoma↗

PubMed1993

Prolonged activation of protein kinase C induces transcription and expression of the alpha 1B adrenergic receptor gene in DDT1 MF-2 cells.

Protein kinase C (PKC) regulates many cellular functions; we have examined the role of PKC in the regulation of the alpha 1B adrenergic receptor gene. Exposure of DDT1 MF-2 cells to phorbol 12-myristate 13-acetate (PMA) (10 nM) increased values of alpha 1B receptor mRNA with peak changes found at 4 h (3.2-fold increase). Increased values of alpha 1B receptor mRNA occurred at PMA concentrations as low as 10 pM with a maximal response at 100 nM. Also, PMA induced a time-dependent increase in the number of alpha 1B receptors. Stimulation of cells with phenylephrine led to an increase in IP3 production after 3, 6, and 12 h of treatment with PMA. Induction of the alpha 1B receptor mRNA was suppressed by the PKC inhibitors H7 (1-(5-isoquinolinylsulsulfonyl)2-methylpiperazine) and saurosporine; the inactive phorbol ester 4 alpha-phorbol didecanoate and calcium ionophores A23187 and Bay K8644 did not increase alpha 1B receptor mRNA. The half-life of the alpha 1B receptor mRNA was unchanged by PMA. Nuclear runoff assays demonstrated that PMA produced a marked increase in the transcription rate of alpha 1B adrenergic receptor expression is mediated by a PKC-dependent mechanism that occurs at the level of transcription.

Animals↗

PubMed1993

Effect of indomethacin on postoperative protein metabolism after gastrectomy under total parenteral nutrition.

A randomized trial was undertaken to evaluate the effects of postoperative indomethacin (IDM) administration on protein metabolism in 20 patients who underwent an uncomplicated distal gastrectomy and were placed on post-operative total parenteral nutrition (TPN). Ten patients (the IDM group) received 50 mg of IDM every 8 h after operation up to postoperative day (POD) 4 while the other ten patients (the control group) received neither IDM nor any other non-steroidal anti-inflammatory drug, postoperatively. Though the requirement for postoperative plasma transfusion was significantly greater in the IDM group, the albumin level on POD 1 was significantly lower in this group than in the control group. The postoperative changes of C-reactive protein, retinol binding protein, and pre-albumin between the two groups showed no difference. Moreover, the urinary 3-methylhistidine excretion, N-balance, and plasma aminogram on POD 4 also demonstrated no difference. We thus concluded that post-operative IDM administration after elective surgery has no additional anti-catabolic effect on the presence of TPN.

Blood Proteins↗

PubMed1992

Schedule-dependent inhibition of thymidylate synthase by 5-fluorouracil in gastric cancer.

BACKGROUND: An optimal treatment schedule of 5-fluorouracil (5-FU) remains to be clarified. METHODS: A randomized study was conducted to investigate schedule-dependent thymidylate synthase (TS) inhibition by 5-FU in 16 patients with gastric cancer who underwent surgical resection. Surgical specimens of tumor, normal gastric mucosa, and regional lymph nodes were obtained 12 hours after administration of 5-FU either as a continuous infusion (1000 mg/m2 for 48 hours) or as a bolus injection (500 mg/m2 x 2 in 48 hours). RESULTS: The total TS activity (567.8 +/- 294 fmol/mg protein) and the rate of TS inhibition (74.7 +/- 23.1%) in cancer tissues were significantly higher in the continuous-infusion group than in the bolus-injection group (228.5 +/- 104.6 fmol/mg protein and 48.8 +/- 12%, respectively). Likewise, the total TS activity (807.4 +/- 440.3 fmol/mg protein) and the rates of TS inhibition in lymph nodes (72.3 +/- 17.1%) and in normal gastric mucosa (85.1 +/- 12.2%) were significantly higher in the continuous-infusion group than those in the bolus-injection group (232.4 +/- 142.3 fmol/mg protein and 53.6 +/- 17.0% in lymph nodes and 46.5 +/- 14.3% in normal gastric mucosa, respectively). There was a significant correlation between the total TS activity and TS inhibition. CONCLUSIONS: Continuous infusion of 5-FU provides a superior antimetabolic effect in the treatment of gastric cancer, which may lead to a superior antitumor effect.

Aged↗

PubMed1992

Establishment of a multi-dose study of chondroitin sulfate iron colloid for evaluation of the reticuloendothelial system function.

The assay system of chondroitin sulfate iron colloid (CSFe) was established to evaluate the reticuloendothelial system (RES) function in individual rabbits. In the multi-dose study of CSFe, CSFe was repeatedly administered to each individual rabbit with increasing doses (0.6, 1.2, 2.4, 6.0 mg/kg) at set intervals. Blood samples were serially collected after injection of CSFe and the concentration of CSFe in serum was directly measured as an iron concentration by modifying the previously described assay method [1] to minimize the sample volume. The clearance rate of CSFe at each injected dose was computed by the least-squares method and the double-reciprocal plotting of the doses against the phagocytic velocities by the Lineweaver-Burk method was obtained in each rabbit. The maximum phagocytic velocity (Vmax) and the CSFe concentration producing 1/2 Vmax (Kp) obtained in ten rabbits were 0.129 +/- 0.025 mg/kg per min and 0.417 +/- 0.121 mg/kg (mean +/- S.D.), respectively. The results obtained from this multi-dose study were comparable to our previous results obtained from the mean values of five groups given different doses [1]. The clearance rates of CSFe (0.6, 1.2, 6 mg/kg) decreased after the co-injection of 80 mg/kg of carbon colloid. The calculated Vmax and Kp in 29 rabbits were 0.125 mg/kg per min and 1.167 mg/kg. The Kp was apparently greater than that of the control (Vmax = 0.128 mg/kg per min, Kp = 0.421 mg/kg). Carbon colloid (80 mg/kg) was injected to six rabbits after the completion of the first multi-dose study of CSFe and then the second multi-dose study of CSFe was repeated after 24 h. No differences were found in Vmax and Kp between the two studies as were in the control group (10 rabbits) where saline was injected instead of carbon colloid. These results indicated that carbon colloid (80 mg/kg) gives a competitive and reversible inhibition on the RES. This multi-dose study of CSFe may be applicable for a bed-side analysis of the RES function in a patient.

Animals↗

PubMed1992

Inhibitory effects of polyethers on human immunodeficiency virus replication.

We examined the inhibitory activities of 10 polyether antibiotics on human immunodeficiency virus (HIV) type 1. These compounds caused concentration-dependent inhibition of HIV replication in primary infected cultures of human T-lymphoblastoid H9 cells. The ratio of 50% effective concentrations for cellular cytotoxicity (MTT assay) to antiviral activity (reverse transcriptase assay) was over 5. Anti-HIV activity was also observed in cultures of monocytic lineage U937 cells chronically infected with HIV.

Anti-Bacterial Agents↗

PubMed1992

[Analgesic effects of epidurally administered fentanyl for postoperative pain relief--comparison with buprenorphine].

We did a retrospective study on 177 patients after upper and lower abdominal surgery, and compared the efficacy of epidural administration of fentanyl and that of buprenorphine for postoperative pain relief. In fentanyl (F) group, 73 patients received fentanyl 0.1 mg with saline 8 ml epidurally after operation, followed by a constant rate infusion of 0.025 mg.hr-1 for 18-24 hrs. In buprenorphine (B) group, 104 patients, received buprenorphine 0.2 mg with saline 9 ml epidurally. After upper abdominal surgery, 33 patients (76.7%) in F group and 27 patients (52.9%) in B group obtained satisfactory analgesia (P < 0.05). The difference of the degree of analgesia after lower abdominal surgery was not significantly different in both groups. Respiratory depression occurred in 19 patients in B group and 5 patients in F group (P < 0.05). It is concluded that epidural fentanyl delivered by continuous infusion offers a significant advantage compared with epidural buprenorphine for postoperative pain relief following upper abdominal surgery.

Abdomen↗

PubMed1992

[Comparison of continuous epidural fentanyl and morphine for postoperative pain management after upper abdominal surgery].

Fentanyl and morphine were administered epidurally to the patients after upper abdominal surgery for postoperative pain management. One hundred and ninety patients were divided into 3 groups; F group: bolus and continuous administration of fentanyl, M group: bolus and continuous administration of morphine, FM group: bolus of fentanyl and morphine and continuous administration of morphine. Pain scores of 1, 2, 3, 4, 8, 12 hours after administration and of the next morning were examined and side effects were recorded. Pain scores at 1 and 2 hours in F and FM group were significantly lower than those in M group. There were no significant differences in the scores among 3 groups from 3 hours to the next morning. The incidence of itching in F group was significantly less than in other groups. Respiratory depression (less than respiratory rate 8.min-1) occurred in 2 cases in M and FM group, but no case in F group. FM group had no advantage compared with F group. We conclude that continuous epidural infusion of fentanyl is more useful than morphine for postoperative pain management after upper abdominal surgery.

Abdomen↗

PubMed1991

cAMP regulates transcription of the alpha 2A adrenergic receptor gene in HT-29 cells.

Since cAMP has a number of important effects regulating activity of adrenergic receptor pathways, we wondered if expression of the alpha 2A adrenergic receptor gene is regulated by this second messenger. We have examined the effects of a cAMP analog (Bt2cAMP) on the expression of alpha 2A adrenergic receptors in HT-29 cells. Bt2cAMP induced a 5.3 +/- 0.8-fold increase in alpha 2A receptor mRNA abundance as did forskolin and vasoactive intestinal polypeptide which both increase cAMP accumulation in these cells. Bt2cAMP increased alpha 2A receptor number up to 2.4 +/- 0.3-fold. The rate of alpha 2A receptor gene transcription increased 7.8 +/- 3.2-fold in cells treated with Bt2cAMP for 2 h; after 24 h, the transcription rate was 3.7 +/- 1.7-fold higher than in controls. The increased rate of transcription occurred in the presence of the protein synthesis inhibitor cycloheximide. The half life of the alpha 2A receptor mRNA in cells incubated with Bt2cAMP for 2 h increased by 1.5-fold but returned to the original value after exposure to Bt2cAMP for 24 h. The increased expression of alpha 2A receptors was associated with an increased efficacy of inhibition of cAMP accumulation mediated by the alpha 2 adrenergic agonist UK14304. Using a chloramphenicol acetyltransferase (CAT) reporter plasmid containing 5'-flanking sequences of the alpha 2A receptor gene, we found that co-transfection of JEG-3 cells with expression vectors containing cAMP-dependent protein kinase regulatory subunit cDNA with mutations at both cAMP binding sites inhibited basal and Bt2cAMP-stimulated expression of CAT activity. These results demonstrate that an alpha 2A adrenergic receptor gene is regulated by the second messenger cAMP via cAMP-dependent protein kinase, mainly by controlling the rate of transcription, which leads to an increased expression of these receptors.

Blotting, Northern↗

PubMed1991

Gene cloning of the maoA gene and overproduction of a soluble monoamine oxidase from Klebsiella aerogenes.

We cloned the structural gene for monoamine oxidase (maoA) from Klebsiella aerogenes into a pKI212 vector in an maoA mutant strain of K. aerogenes. Deletion analysis and complementation tests of the recombinant plasmid showed that the maoA gene was located entirely within a 4.1-kb segment. In an maoA mutant strain harbouring the cloned maoA gene, synthesis of monoamine oxidase was induced by addition of tyramine and related compounds. Transfer of a plasmid containing the maoA gene into a monoamine oxidase-producing strain of K. aerogenes W70 resulted in about a 30- to 40-fold increase in total production of the enzyme. When cells of K. aerogenes carrying the plasmid containing the maoA gene were grown with tyramine, more than 85% of the monoamine oxidase was produced in soluble form, whereas the parent strain W70 produced most monoamine oxidase as the membrane-bound form.

Chromosome Deletion↗

PubMed1991

Evaluation of the reticuloendothelial system function by the vascular clearance of chondroitin sulfate iron colloid.

Vascular clearance of chondroitin sulfate iron colloid (CSFe) was evaluated as a test for the reticuloendothelial system (RES) in rabbits. Injected CS59Fe was taken up by the RES in the liver (49%) and bone marrow (41%) after 60 min, suggesting its application for the RES function test. The clearance rate (K-value) of CSFe from the blood was calculated by measuring serum Fe concentrations after releasing iron from CSFe at certain intervals after injection. Depending upon different injected doses, K-values were varied and the phagocytic velocity, computed by multiplying K-values by corresponding injected doses, reached a plateau at high doses, indicating the phagocytosis of CSFe by the RES takes a saturation process. Double-reciprocal plotting of the dose and the phagocytic velocity showed a linear relationship, which provided the data on the maximum phagocytic velocity (Vmax), 0.122 mg/kg/min, and the CSFe concentration producing 1/2 Vmax (Kp), 0.426 mg/kg. Thus, this CSFe clearance test can be used for the evaluation of the RES function.

Animals↗

PubMed1991

Glucocorticoids induce transcription and expression of the alpha 1B adrenergic receptor gene in DTT1 MF-2 smooth muscle cells.

Steroid hormones modulate physiological processes by a number of mechanisms including regulation of gene expression. We wondered if glucocorticoids might induce expression of alpha 1 adrenergic receptors, which could contribute to the increased sensitivity of vascular smooth muscle to catecholamines that may occur with glucocorticoid excess. We examined the effects of dexamethasone on the expression of the alpha 1B adrenergic receptor gene in DDT1 MF-2 smooth muscle cells. Dexamethasone (10(-6) M) produced a 1.8 +/- 0.2-fold increase in expression of alpha 1B receptors determined with [3H]prazosin. Steady-state values of alpha 1B adrenergic receptor mRNA, analyzed by Northern blotting, increased 2.8 +/- 0.7-fold after 48 h exposure to dexamethasone. This effect of dexamethasone occurred in the presence of the protein synthesis inhibitor cycloheximide. alpha 1B receptor mRNA abundance was also increased by testosterone and aldosterone, whereas beta estradiol and progesterone had no effect. The alpha 1B receptor gene transcription rate, determined in nuclear run-off assays, increased 2.6 +/- 0.6-fold in cells treated with dexamethasone for 24 h. The half-life of the alpha 1B receptor mRNA was unchanged by dexamethasone. These data indicate that glucocorticoids regulate expression of alpha 1B receptors by increasing the rate of transcription of this gene.

Animals↗

PubMed1989

Activation of type I cyclic AMP-dependent protein kinases is impaired by a point mutation in cyclic AMP binding sites.

The type I regulatory (R-I) subunit of cyclic AMP-dependent protein kinase (A-kinase) was expressed in E. coli, and a single amino acid substitution in cyclic AMP binding sites A or B was introduced by site-directed mutagenesis. The cyclic AMP binding activity and cyclic AMP-stimulated phosphotransferase activity of the holoenzymes formed by wild-type or mutant R-Is and the purified bovine catalytic subunit of A-kinase were then examined. The wild-type holoenzyme was activated by low concentrations of cyclic AMP, a finding in accord with its high-affinity binding to cyclic AMP. In contrast, although the two mutant holoenzymes showed high-affinity cyclic AMP binding at their non-mutated sites, both holoenzymes were resistant to activation by cyclic AMP. Thus, binding of cyclic AMP to the non-mutated cyclic AMP binding site is not sufficient to dissociate the catalytic subunit from the mutant R-Is upon cyclic AMP binding. These results suggest that both A and B cyclic AMP binding sites are required for efficient coupling between cyclic AMP binding and activation of the enzyme.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1989

Induction of the acrosome reaction in ejaculated goat spermatozoa by preincubation in chemically defined medium.

The aim of the present study was to examine the effects of the elimination of energy substrate from the medium and the effects of the preincubation vessel, temperature, and time on the induction of the acrosome reaction in ejaculated goat spermatozoa in chemically defined medium. Washed spermatozoa were resuspended in Brackett-Oliphant (BO) medium or substrate-free BO medium to give a high concentration and preincubated in open test tubes or sealed glass tubes at 37.0 or 39.5 degrees C for 1, 2, or 3 h. Sperm acrosome reaction was evaluated using a simplified triple-stain technique and a hamster test. It was found that the goat sperm acrosome reaction occurred more readily in the sealed glass tubes than in open test tubes, in substrate-free BO medium than in BO medium, and at 39.5 than at 37.0 degrees C. During preincubation with substrate-free BO medium in sealed glass tubes at 39.5 degrees C, the optimum time necessary to induce the acrosome reaction in goat spermatozoa was 2-3 h.

Acrosome↗

PubMed1988

Site-directed mutagenesis of the cAMP-binding sites of the recombinant type I regulatory subunit of cAMP-dependent protein kinase.

The type I regulatory subunit (R-I) of rat brain cAMP-dependent protein kinase was expressed in E. coli and site-directed mutagenesis was used to substitute amino acids in the putative cAMP-binding sites. The wild-type recombinant R-I bound 2 mol of cAMP/mol subunit, while two mutant R-Is with a single amino acid substitution in one of the two intrachain cAMP-binding sites (clone N153:a glutamate for Gly-200, and clone C254:an aspartate for Gly-324) bound 1 mol of cAMP/mol subunit. When these two substitutions were made in one mutant, cAMP did not bind to this mutant, indicating that binding of cAMP to N153 or C254 was to their nonmutated sites. Competition experiments with site-selective analogs and dissociation of bound cAMP from mutant R-Is provided evidence for strong intrachain interactions between the two classes of cAMP-binding sites in R-I.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1988

Immunohistochemical localization of gamma-aminobutyric acid in the rat pituitary gland and related hypothalamic regions.

The distribution of gamma-aminobutyric acid (GABA) containing neurons in the rat pituitary gland and related hypothalamic areas was immunohistochemically investigated using antibodies raised against GABA conjugated to bovine serum albumin by glutaraldehyde. A dense network of GABA-like immunoreactive fine varicose nerve fibers was observed within the posterior and intermediate lobes of the pituitary gland, surrounding endocrine cells and capillaries, but not in the anterior lobe. In the pituitary stalk, the dense varicose fibers ran along the anterior wall of the posterior lobe into the posterior and intermediate lobes. A small number of GABA-like immunoreactive cell bodies were evident in the intermediate lobe. GABA-like immunoreactive fibers occurred at low to high density in most parts of the hypothalamus. GABA-like immunoreactive neurons were observed in some regions related to the pituitary gland (such as periventricular nucleus, paraventricular nucleus, arcuate nucleus and accessory magnocellular nucleus). These results provide morphological evidence for the presence of GABAergic neurons in the rat hypothalamo-pituitary system.

Animals↗