PubMed Health⌕ Search

Biomedical subjects

K Manabe

Publications and source records attributed to K Manabe.

At least 109 records · Page 6Linked to original sources
PubMed1991

Two-dimensional gel electrophoresis of the membrane-bound protein complexes, including photosystem I, of thylakoid membranes in the presence of sodium oligooxyethylene alkyl ether sulfate/dimethyl dodecylamine oxide and sodium dodecyl sulfate.

Two-dimensional polyacrylamide gel electrophoresis (PAGE), using a mixture of sodium oligooxyethylene alkyl ether sulfate and dimethyl dodecylamine oxide as detergents (AES-DDAO mixture) in the first dimension and sodium dodecyl sulfate (SDS) in the second dimension, was developed and applied to an analysis of the photosystem I (PS I) complex in thylakoid membranes prepared from spinach chloroplasts. When thylakoid membranes of chloroplasts were solubilized directly in the AES-DDAO mixture and subjected to PAGE in the presence of these detergents as the first dimension, some protein complexes containing chlorophyll were observed. The protein components in these complexes separated into an array of polypeptide spots when the strip of gel after PAGE in the first dimension was subjected to PAGE in the presence of SDS as the second dimension. The main band of protein which separated in the first dimension was demonstrated to be the PS I complex. This complex retained the intrinsic photochemical activity of P700 even after it was subjected to one-dimensional PAGE. These results suggest that certain protein complexes can be separated, with the maintenance of their original structures, by electrophoresis in the presence of the AES-DDAO mixture, and this method appears to have valuable potential for analysis of the components of membrane-bound protein complexes.

Cell Membrane↗
PubMed1991

Determination of hippuric acid and o-, m- and p-methylhippuric acids in urine by capillary gas chromatography.

A capillary gas chromatographic (GC) method for the simultaneous determination of urinary hippuric acid (HA) and o-, m- and p-methylhippuric acids (MHAs), metabolites of toluene and o-, m- and p-xylenes, respectively, is described. These metabolites are converted into their isopropyl derivatives by extractive alkylation with tetrahexylammonium ion as extracting agent and isopropyl bromide as alkylating reagent in benzene. The derivatives are analysed using a chromatograph equipped with hydrogen flame ionization detector, split injection system and DB-17 capillary column. Benzoylleucine is used as an internal standard. The derivatives are well separated within 5 min and no interfering peaks are observed. The calibration curves of HA and MHAs in the range 1-50 micrograms are linear and sufficiently reproducible for quantitative analysis. Urine can be analysed accurately and precisely by this method without prior clean-up of the sample.

Animals↗
PubMed1991

Progesterone metabolism in recombinant yeast simultaneously expressing bovine cytochromes P450c17 (CYP17A1) and P450c21 (CYP21B1) and yeast NADPH-P450 oxidoreductase.

Simultaneous expression plasmids were constructed for bovine adrenal cytochromes P450c17 and P450c21 (pA gamma alpha) and for both P450s together with NADPH-cytochrome P450 reductase (pAR gamma alpha). On introduction of each of the plasmids into Saccharomyces cerevisiae AH22 cells, the transformed yeast strains AH22/pA gamma alpha and AH22/pAR gamma alpha produced about 10(5) molecules per cell of P450c17 and 2 x 10(3) molecules per cell of P450c21. The expression levels of NADPH-cytochrome P450 reductase was about 3 x 10(4) and 6 x 10(5) molecules per cell in the strains AH22/pA gamma alpha and AH22/pAR gamma alpha, respectively. When progesterone was added to growing cell cultures of the transformed yeast strains, the substrate was metabolized more rapidly in the AH22/pAR gamma alpha cells than AH22/pA gamma alpha cells, probably due to overproduction of the reductase. In the AH22/pAR gamma alpha cells, progesterone was first converted into 17 alpha-hydroxyprogesterone to the extent of 82% by the catalysis of P450c17. 17 alpha-hydroxyprogesterone was further converted into 11-deoxycortisol by P450c21 to the extent of 60% of the added substrate. The conversion of progesterone into androstenedione through 17 alpha-hydroxyprogesterone was estimated to be less than 3%, suggesting very low C17,20-lyase activity of P450c17, although other hydroxylation products were detected. Androstenedione was further converted into testosterone by an unknown pathway present in S. cerevisiae cells.

17-alpha-Hydroxyprogesterone↗
PubMed1990

Determinants of pigeons' waiting time: Effects of interreinforcement interval and food delay.

Four pigeons performed on three types of schedules at short (i.e., 10, 30, or 60 s) interreinforcement intervals: (a) a delay-dependent schedule where interreinforcement interval was held constant (i.e., increases in waiting time decreased food delay), (b) an interreinforcement-interval-dependent schedule where food delay was held constant (i.e., increases in waiting time increased interreinforcement interval), and (c) a both-dependent schedule where increases in waiting time produced increases in interreinforcement interval but decreases in food delay. Waiting times were typically longer under the delay-dependent schedules than under the interreinforcement-interval-dependent schedules. Those under both-dependent schedules for 1 subject were intermediate between those under the other two schedule types, whereas for the other subjects waiting times under the both-dependent procedure were similar either to those under the delay-dependent schedule or to those under the interreinforcement-interval-dependent schedule, depending both on the subject and the interreinforcement interval. These results indicate that neither the interreinforcement interval nor food delay is the primary variable controlling waiting time, but rather that the two interact in a complex manner to determine waiting times.

Journal Article↗
PubMed1990

Additional-delay schedules: A continuum of temporal contingencies by varying food delay.

Pigeons performed on discrete-trial, temporally defined schedules in which the food delay (D) was adjusted according to the latency of the key peck (X) and two schedule parameters (t and A). The schedule function was D = A(t - X), where D is the experienced delay between a response and a reinforcer. The schedule parameter t is the maximum value below which the present contingencies occur. A is the additional delay to reinforcement for each second the response latency is shorter than the t value. When A = 0 s, the schedule is a continuous reinforcement schedule with immediate reinforcement. When A = 1 s, the schedule is a conjunctive fixed-ratio 1 fixed-time t-s schedule. When A approaches infinity, the schedule becomes a differential reinforcement of long latency schedule. The latencies for subjects with t = 10 s and t = 30 s were observed with the present schedules having seven values for A between 0 s and 11 s. In addition, the latencies for subjects for which t = 30 s were observed at an A value of 31 s to 41 s. As the A value increased, the latencies approached the t value for subjects for which t = 10 s. The latencies for 30-s-t subjects did not approach t, even when the A value was 41 s. The latencies for 10-s-t subjects at 11-s A value were longer than those under yoked conditions having exactly the same delays/interreinforcement intervals. These results demonstrated a continuum of latency related to the schedule continuum (value of A) at a small t value.

Journal Article↗
PubMed1989

Vasorelaxing effects of prostaglandin I2 on the canine basilar and coronary arteries.

The effects of prostaglandin (PG) I2 on canine basilar and coronary arteries were studied. PGI2 caused a relaxation from the basal level more effectively in the endothelium-intact preparations of the coronary artery than in those of the basilar artery. The PGI2-induced relaxation in the basilar artery was enhanced by removal of the endothelium, and by treatment with indomethacin (10(-6) M), aspirin (5 X 10(-5) M), both cyclooxygenase inhibitors, OKY-046 (3 X 10(-5) M) and RS-5186 (10(-6) M), both thromboxane (TX) A2 synthetase inhibitors and ONO-3708 (10(-8) M), a TXA2 antagonist. The enhancing effects of removal of the endothelium and treatment with indomethacin and aspirin on the PGI2-induced relaxation were greater than those of treatment with OKY-046, RS-5186 and ONO-3708. The PGI2-induced relaxation in the coronary artery was not affected by removal of the endothelium, treatment with indomethacin (10(-6) M) or methylene blue (10(-6) M). In the endothelium-removed preparations precontracted with a TXA2 agonist, PGI2-induced relaxation was less in the basilar artery than in the coronary artery. The present experiments suggest that endothelium-derived factors (TXA2 and other cyclooxygenase products) counteract the vasorelaxing effect of PGI2 in the canine basilar artery, but not in the coronary artery.

Animals↗
PubMed1989

[Clinical evaluation of CA-50 in cases with colorectal cancer].

Serum CA-50 has been evaluated in 67 healthy donors and in 46 patients with a colorectal cancer by an enzyme immunoassay (EIA Kit, Mitsui pharmaceuticals, Inc.). The mean value of the healthy donors (n = 67) was 10.6 +/- 6.1 U/ml and for patients with a colorectal cancer 31.7 +/- 55.2 U/ml. Both in healthy donors and in patients, the mean value was found to be higher in females than males. The overall sensitivity in the colorectal cancer patients was 26.1 percent, the percentages for those in stage I, 20, II, 9.1, III, 40, IV, 20, and V, 50% respectively. In a correlation between serum CA-50 and CA 19-9, the correlation coefficient was 0.82 (p less than 0.01), and in between CA-50 and CEA, 0.51 (p less than 0.01). Thus a combination assay among CA-50, CA 19-9, and CEA has proved to be of significant value in cases of a colorectal cancer.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1989

Endothelium-dependent contractions induced by angiotensin I and angiotensin II in canine cerebral artery.

Whether angiotensin I and angiotensin II caused endothelium-dependent contraction was examined in canine cerebral arteries. In endothelium-intact preparations, angiotensin I and angiotensin II at 10(-8) to 10(-6) M caused dose-dependent contractions, whereas both angiotensins caused much less contractions in endothelium-removed preparations. The contractions induced by angiotensin I and angiotensin II were strongly attenuated by aspirin (cyclooxygenase inhibitor) (5 x 10(-5) M), OKY-046 [thromboxane (TX) A2 synthetase inhibitor] (10(-5) M) and ONO-3708 (TX)A2 antagonist) (5 X 10(-9) M). Captopril (10(-6) M) significantly attenuated the contractions induced by angiotensin I but not those induced by angiotensin II. Angiotensin I- and angiotensin II- induced contractions were inhibited markedly by Sar1, Ala8-angiotensin II (10(-9) and 10(-8) M). The present experiments demonstrate that angiotensin I and angiotensin II produce endothelium-dependent contraction in canine cerebral artery via a factor which appears to be TXA2. Angiotensin I may be converted by endothelial cells to angiotensin II, which may activate the cells to produce TXA2 in canine cerebral artery.

Angiotensin I↗
PubMed1988

An endothelium-dependent contraction induced by A-23187, a Ca++ ionophore in canine basilar artery.

In most isolated canine basilar arteries tested, Ca++ ionophore A-23187 induced a small relaxation followed by a transient contraction. Both contraction and relaxation were abolished by removal of endothelium. The endothelium-dependent contraction induced by A-23187 was attenuated by a phospholipase A2 inhibitor (quinacrine), cyclooxygenase inhibitors (aspirin and indomethacin), a thromboxane A2 (TXA2) synthetase inhibitor (OKY-046) and a TXA2 antagonist (ONO-3708). The A-23187-induced contraction was abolished by lowering the Ca++ concentration of medium to 10%, whereas the contraction induced by 9,11-epithio-11,12-methano-TXA2 (STA2) was attenuated slightly by lowering [Ca++]. The A-23187-induced contraction was reduced markedly by nifedipine (10(-9) to 10(-7) M), but the STA2-induced contraction was only attenuated slightly by nifedipine. Bay K 8644 did not affect the A-23187- and STA2-induced contractions. The present experiments demonstrate that A-23187 induced an endothelium-dependent contraction in canine basilar artery, and suggest that Ca++ might play a key role in production of an endothelium-derived contracting factor (probably TXA2).

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1988

[Clinical evaluation of a combination assay of CEA, CA-19-9 and TPA in patients with colorectal cancer].

The effectiveness of serum CEA (56 cases), CA-19-9 (53 cases) and TPA (48 cases) in patients with colorectal cancer has been evaluated. The preoperative sensitivity and specificity of CEA and CA 19-9 were found to be almost the same in level but the level of TPA was low. In 20 cases recurrent, the sensitivity of the marker was 66.7% in the liver, 60% in the lung, and 66.7% in the local recurrence of primary foci. In these recurrent cases, serum CEA in initially elevated to 65%, CA 19-9 to 25%, and TPA to only 10%. In diagnostic rate imaging or in our clinical findings, however, the frequency was almost the same as tumor markers.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1988

Endothelium-dependent contraction and -independent relaxation induced by adenine nucleotides and nucleoside in the canine basilar artery.

ATP, ADP, AMP and adenosine at 10(-8) induced a slight relaxation, and at concentrations greater than 10(-7) M caused a biphasic response consisting of an initial relaxation followed, after a brief period, by a transient contraction in canine basilar artery. ATP (10(-6) and 10(-5) M) caused a triphasic response consisting of a rapid, small contraction, a relaxation and then a second, transient contraction. The order of agonist potency for contraction was ATP greater than ADP much greater than AMP = adenosine, but for producing relaxation the agonists were equipotent. Removal of the endothelium abolished the contraction after the relaxation, but had virtually no effect on the relaxation and the rapid contraction induced by ATP (10(-6) and 10(-5) M). Only the relaxation in response to ATP (10(-6) M) was attenuated by removal of the endothelium. Aspirin (a cyclooxygenase inhibitor) (5 X 10(-5) M), OKY-046 (a thromboxane A2 synthetase inhibitor) (10(-5) M) and ONO-3708 (a thromboxane A2 antagonist) (5 X 10(-9) M) attenuated markedly the endothelium-dependent contraction induced by ATP (10(-5) M) and ADP (10(-5) M), but did not affect the relaxation. Phentolamine (10(-6) M) and atropine (10(-6) M) did not affect either the contraction or the relaxation. The relaxations induced by both ATP and adenosine in both endothelium-intact preparations and endothelium-removed preparations were attenuated by 8-phenyltheophylline (P1 antagonist) (10(-6) M).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenine Nucleotides↗
PubMed1986

Immunohistochemical study of HLA class 1 antigens on the hepatocytes of patients with chronic hepatitis B.

In order to evaluate the role of histocompatibility antigen (HLA) class 1 antigens in the pathogenesis of liver cell necrosis, HLA class 1 antigens on hepatocytes were studied in the liver biopsy materials from 20 patients with chronic hepatitis B by the peroxidase-labeled antibody method using a monoclonal antibody to human HLA-A, B, C (Cappel Laboratories). Both increased expression of HLA class 1 antigens on the hepatocytes and decreased distribution of intrahepatic hepatitis B core antigen (HBcAg) were observed in patients with an exacerbation of the inflammatory activity. These findings suggest that expression of HLA class 1 antigens on the hepatocytes may be increased when an exacerbation of inflammatory activity develops, and may be compatible with the concept that expression of these antigens plays and important role for the lysis of hepatitis B virus (HBV)-infected liver cells by cytotoxic T cells. Furthermore, in seven patients, expression of HLA class 1 antigens was studied in the liver before and after treatment with human lymphoblast interferon (IFN)-alpha, recombinant IFN-alpha or IFN-beta. Increased expression of HLA class 1 antigens was observed in patients with decreased intrahepatic HBcAg and DNA-P in sera after IFN treatment. These results also suggest that the increase of HLA class 1 antigens by IFN may be related to the immune mechanism for the effective elimination of HBV.

Adult↗
PubMed1986

Effects of adenine arabinoside on cellular immune responses in patients with chronic hepatitis B.

The lymphocyte subsets in the peripheral blood and in liver biopsies from 4 patients with chronic hepatitis B obtained about 2-7 weeks before and after treatment with adenine arabinoside (Ara-A) were studied by a peroxidase-labeled antibody method using monoclonal antibodies against Leu-1, Leu-2a, Leu-3a, Leu-7 and Leu-10 antigens. In the peripheral blood, the percentage of Leu-2a+ (cytotoxic/suppressor) cells was significantly reduced and the ratio of Leu-3a+ (helper/inducer) to Leu-2a+ cells was increased after the treatment with Ara-A. In the liver biopsies, the numbers of Leu-1+ (pan T) and Leu-2a+ cells were significantly decreased after the treatment with Ara-A. As a result, the Leu-3a+/Leu-2a+ ratio was significantly elevated in the liver after the therapy. The majority of lymphocytes distributed at sites of hepatocytic necrosis were positive for Leu-2a. The reduced numbers of Leu-1+ and Leu-2a+ cells after the treatment were mainly due to the decrease of these cells infiltrating to the sites of hepatocytic necrosis. The numbers of other subsets (Leu-3a+, Leu-7+ and Leu-10+) changed without any specific tendency both in the peripheral blood and in the liver biopsies after the treatment. With respect to viral replication, most of the patients showed a decrease of serum DNA polymerase activity or demonstrable intrahepatic HBsAg and HBcAg after the treatment. These data suggest that T cell-mediated cytotoxicity against HBV-infected hepatocytes is diminished after treatment with Ara-A.

DNA-Directed DNA Polymerase↗
PubMed1986

Tubular structures in the hepatic nuclei of a patient with delta agent.

Liver biopsy specimens obtained from a 31-year-old female with delta-positive hepatitis were studied by routine electron microscopy. In several nuclei of hepatocytes, there were filamentous or microtubular structures 15 to 20 nm in diameter, in the vicinity of which, round particles, probably cross sections of tubular ones, were seen. In these nuclei, irregular granules approximately 20 to 30 nm in diameter were also found in clusters. However, cores of Dane particles were not found in such hepatocytes. These intranuclear microtubular structures may be associated with delta agent.

Adult↗