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Biomedical subjects

K Kurachi

Publications and source records attributed to K Kurachi.

At least 109 records · Page 6Linked to original sources
PubMed1984

Isolation of a human cDNA for alpha 2-thiol proteinase inhibitor and its identity with low molecular weight kininogen.

A lambda gt11 cDNA library containing DNA inserts prepared from human liver mRNA has been screened with an antibody to human alpha 2-thiol proteinase inhibitor that was isolated from fresh plasma. Eighteen positive clones were isolated from one million phage, and each was plaque purified. The cDNA insert of one of these phage was sequenced and shown to code for alpha 2-thiol proteinase inhibitor as identified by a partial amino acid sequence of the light chain of alpha 2-thiol proteinase inhibitor. This cDNA insert contained 1529 base pairs coding for the complete alpha 2-thiol proteinase inhibitor. It included 45 base pairs of 5' noncoding sequence, 1281 base pairs that code for pre alpha 2-thiol proteinase inhibitor, a stop codon, 160 base pairs of 3' noncoding sequence, and 40 base pairs of poly(A) tail. The noncoding sequence on the 3' end contained a potential recognition site (AATAAA) for processing and polyadenylation of precursor messenger RNA. The amino acid sequence of alpha 2-thiol proteinase inhibitor deduced from the cDNA showed a striking similarity (overall homology at 74%) to that of bovine low molecular weight (LMW) kininogen, including two internally repeated sequences and a nonapeptide sequence of bradykinin. These data clearly indicated that alpha 2-thiol proteinase inhibitor and LMW kininogen are identical. This was further supported by immunological cross-reactivity between alpha 2-thiol proteinase inhibitor and LMW kininogen.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1984

Argyrophil cells in the endometrioid carcinoma of the ovary.

Of 42 endometrioid carcinomas of the ovary examined with Grimelius staining, 19 tumors were found to have argyrophil cells. Argyrophil cells were subgrouped into two types according to the distribution of the argyrophil granules. Type I cells contained argyrophil granules in the basal part of the cytoplasm, and were found in four tumors. Type II cells contained argyrophil granules mainly in the apical portion or throughout the whole cytoplasm, and were found in 14 tumors. Both type I and II cells were found in different areas of one tumor. In type II cells, the distribution of argyrophil granules was similar to that of mucins, and the apical argyrophilia was diminished in varying degrees in some tumors after diastase digestion. The distribution of argyrophil granules paralleled that of secretory granules identified by electron microscopy in the representative tumors of each type. In the immunohistochemical study, somatostatin was found in a tumor with both types of argyrophil cells. Somatostatin-containing cells generally corresponded to type I cells, but were less numerous than argyrophil cells.

Adenocarcinoma↗
PubMed1984

Complete sequence of the cDNA for human alpha 1-antitrypsin and the gene for the S variant.

A 1434 base pair human liver cDNA coding for the entire alpha 1-antitrypsin protein has been isolated and sequenced. Translation of the coding region into amino acids reveals a precursor molecule which contains a 24 amino acid signal peptide and 394 amino acids present in the mature polypeptide chain. The human gene for the S variant of alpha 1-antitrypsin has also been subcloned and sequenced. The gene is composed of 10226 nucleotide bases and is approximately equimolar for all 4 nucleotides. The gene contains four intervening sequences (introns) and 5' and 3' noncoding regions which are 54 and 79 nucleotides in length, respectively. A 5.3-kilobase intron exists in the 5' noncoding region and contains a 143 amino acid open reading frame, an Alu family sequence, and a pseudo transcription initiation region. No significant differences in base composition are seen between the introns and those regions corresponding to coding regions of the corresponding mRNA (exons). A sequence of 1951 nucleotides flanking the 5' end of the gene has also been determined and contains a "TATA" box sequence (TTAAA-TA) 21 nucleotides upstream from the proposed transcription start site. Comparison of the gene sequence with the cDNA sequence reveals a single base substitution (A----T), which results in a Glu----Val substitution at position 264 in the S variant protein. The position and size of introns, the overall base composition, and the codon preference for the alpha 1-anti-trypsin gene differ from those for the chicken ovalbumin gene even though the two proteins belong to a common protein family, as judged by amino acid sequence homology.

Amino Acid Sequence↗
PubMed1984

Effect of pituitary transplants on the LH-RH concentrations in the medial basal hypothalamus and hypophyseal portal blood.

The effects of hyperprolactinemia on catecholamine turnover in the medial basal hypothalamus (MBH) and on the luteinizing hormone-releasing hormone (LH-RH) concentrations in MBH and hypophyseal portal blood were investigated in female Wistar rats. Chronic endogenous hyperprolactinemia was produced by implantation of anterior pituitary glands under the kidney capsule. Catecholamine turnover in the MBH was studied by inhibiting monoamine oxidase and then measuring the accumulation of catecholamines by high-performance liquid chromatography with electrochemical detection. Rats bearing pituitary transplants exhibited: (1) persistent vaginal diestrus within 3-6 days of the implantation; (2) increased serum concentrations of prolactin (PRL); (3) decreased serum concentrations of luteinizing hormone (LH); (4) increased pituitary concentrations of LH and follicle-stimulating hormone (FSH); (5) increased turnovers of dopamine in the MBH; and (6) decreased concentrations of LH-RH in the MBH and in plasma of hypophyseal portal blood. These findings suggest that chronic hyperprolactinemia may increase dopaminergic tone in the MBH that may inhibit LH-RH secretion from the MBH, and LH release from the pituitary. These processes may be responsible for disturbances of cyclic pituitary-ovarian activity.

Animals↗
PubMed1984

Active-site mapping of bovine and human blood coagulation serine proteases using synthetic peptide 4-nitroanilide and thio ester substrates.

A series of 14 tripeptide 4-nitroanilide substrates of the type Z-AA-Gly-Arg-NA and Z-AA-Phe-Arg-NA where AA = Ala, Asn, Glu, Lys, Phe, Pro, or Ser were used to map the S3 subsite of several serine proteases involved in blood coagulation. The enzymes studied included bovine thrombin, factor IXa, factor Xa, factor XIa, human beta-factor XIIa (factor XIIa fragment), and activated bovine and human protein C. Kinetic constants (kcat, KM, and kcat/KM) for the enzymatic hydrolysis of the substrates by each enzyme were determined and used to compare the relative reactivities of the individual enzymes. Most of the enzymes reacted with all the substrates, although a few showed considerable specificity. Human beta-factor XIIa showed the highest reactivity of all the coagulation proteases studied and was also very substrate specific (kcat/KM ranged over 470-fold). The best substrate was Z-Lys-Phe-Arg-NA with kcat/KM = 140 000 M-1 s-1. Activated bovine protein C (best substrate = Z-Ser-Phe-Arg-NA), factor Xa (best substrate = Z-Glu-Gly-Arg-NA), and thrombin (best substrate = Z-Lys-Gly-Arg-NA) were the group of enzymes that showed next highest reactivity toward the substrates. Activated bovine protein C, thrombin, and factor Xa displayed relatively little substrate specificity. Activated human protein C (best substrate = Z-Ser-Phe-Arg-NA) and factor XIa (best substrate = Z-Glu-Gly-Arg-NA) are moderately reactive enzymes. Activated human protein C is an extremely specific enzyme since it has such a large range of kcat/KM values.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Replenishment of pituitary estrogen receptor in chronically estrogenized rats.

Replenishment of pituitary estrogen receptor (ER) following a single injection of estradiol-17 beta (E2) was examined in chronically estrogenized ovariectomized rats. Subcutaneous implantation of E2-pellet in castrated rats for 7 days caused a shift of ER distribution in the pituitary (39.9 +/- 5.7 fmol/10 mg tissue in the cytosol vs 24.8 +/- 1.9 fmol/10 mg tissue in the nucleus). An intraperitoneal injection of 5 micrograms E2 in the E2-implanted rats resulted in a significant decrease in cytosol ER with a concomitant significant increase in nuclear ER (16.6 +/- 1.2 fmol in the cytosol vs. 36.7 +/- 4.1 fmol in the nucleus at 1 h). However, cytosol ER was rapidly replenished, which was accompanied by nuclear ER reduction, and both values returned to the pre-injection levels at 4 h. An administration of 150 micrograms cycloheximide, that effectively blocked protein synthesis in the E2-implanted and 5 micrograms E2 injected rats, completely inhibited the replenishment of ER. These findings suggest that replenishment of ER following E2 administration in the pituitary of chronically estrogenized rats is entirely dependent on protein synthesis.

Animals↗
PubMed1984

Divergent effects of prolactin on 4-ene-5 alpha-reductase activity and production of C19-steroids from progesterone in immature rat ovary.

Female rats of the Sprague-Dawley strain were used. Two pituitaries from 9-week old rats were grafted in both kidneys of 21-day old rat to induce hyperprolactinemia. All rats with or without pituitary isografts were hypophysectomized on day 26. Starting from day 29, the rats in groups of 8-11 were injected daily with 5 micrograms NIH-LH-S19 or saline for 3 days. Ovarian homogenates from these rats on day 32 were incubated with [14C]4-androstene-3,17-dione or [3H]progesterone and steroid metabolism was estimated. In the hypophysectomized rat ovary, the 5 alpha-reductase activity was stimulated significantly by LH. Although pituitary isograft alone had no stimulative effect on 5 alpha-reductase activity of the hypophysectomized rat ovary, concomitant treatment with LH and pituitary isograft (prolactin) had an additive effect. Formation of the sum of C19-steroids from progesterone in the hypophysectomized rat ovary was stimulated markedly by LH but reduced slightly by prolactin. The LH-induced production of C19-steroids from progesterone was inhibited markedly by prolactin. These results indicate that prolactin treatment inhibits basal and LH-induced production of C19-steroids from progesterone but stimulates LH-induced 4-ene-5 alpha-reductase activity in immature rat ovary.

Androgens↗
PubMed1984

Specific antibodies to porcine zona pellucida detected by quantitative radioimmunoassay in both fertile and infertile women.

The specific radioimmunoassay system was developed for the titration of the antibodies to porcine zona pellucida (ZP) in human sera by using 125I-labeled purified porcine ZP as antigen, which is known to have cross-reactivity with human ZP. The antibodies in human sera were detected in 3 of 11 (27%) women with unexplained infertility, in 16 of 48 (33%) amenorrheic patients, in 4 of 12 (33%) fertile women, and in 3 of 10 (30%) men. Moreover, antibody titers in infertile women were no higher than those in fertile women and in men. These results seem to suggest that the antibodies in human sera that cross-react with porcine ZP may not be an important factor in causing infertility in women.

Animals↗
PubMed1984

Characterization of a cDNA coding for human factor X.

A lambda gt11 cDNA library containing DNA inserts prepared from human liver mRNA has been screened with an antibody to human factor X, a plasma protein participating in the middle phase of the blood coagulation cascade. Ten positive clones were isolated from 2 X 10(6) phage and plaque purified. The cDNA in the phage containing the largest insert has been sequenced and shown to code for human factor X. This cDNA insert contained 1137 base pairs coding for a portion of the light chain of the molecule, a connecting region, the heavy chain, a stop codon, a short 3' noncoding region, and a poly(A) tail. The sequence of A-T-T-A-A-A, which functions as a potential recognition site for polyadenylylation or processing, was present in the 3' end of the coding sequence and preceded the stop codon of TGA by 1 base pair and the poly(A) tail by 14 base pairs. The amino acid sequence deduced from the cDNA indicated that factor X is synthesized as a single-chain polypeptide containing the light and heavy chains connected by an Arg-Lys-Arg tripeptide. The single-chain molecule is then converted to the light and heavy chains by cleavage of two (or more) internal peptide bonds. In plasma, these two chains are linked together by a disulfide bond. The DNA sequence coding for the active site of human factor X showed a high degree of identity with prothrombin and factor IX, two other vitamin K-dependent serine proteases that participate in blood coagulation. These data along with the protein sequence data previously published for the light chain of human factor X establish the complete amino acid sequence for the mature protein present in plasma.

Amino Acid Sequence↗
PubMed1984

Impaired LH-RH release by estrogen in women with sulpiride-induced hyperprolactinemia.

The effects of hyperprolactinemia on the release of immunoreactive luteinizing hormone-releasing hormone (LH-RH) and luteinizing hormone (LH) in response to iv injection of 20 mg conjugated estrogens (Premarin) were studied. Five normal cycling women were injected with Premarin on the morning of the 7th day of the first cycle (control cycle), and then the plasma levels of LH-RH, LH, and prolactin (PRL) were determined every 8 to 16 hours for 72 h. Two months later, the same women received 200 mg of oral sulpiride daily for 8 days from the 3rd day of the cycle (sulpiride treated cycle), and then the same protocol as in the control cycle was applied. Mean (+/- SE) plasma levels of PRL on day 7 in the sulpiride treated cycle were significantly higher than those in the control cycle (118 +/- 24 ng/ml vs. 14 +/- 4 ng/ml, p less than 0.001). After estrogen injection, the mean percent increases in immunoreactive LH-RH at 32 h (control: 71 +/- 38% vs. sulpiride: 6 +/- 36%) and 40 h (154 +/- 38% vs. -5 +/- 21%) and in LH at the 48 h (175 +/- 89% vs. 57 +/- 57%) and 56 h (99 +/- 32% vs. 7 +/- 21%) were significantly (p less than 0.01 or p less than 0.05) suppressed in the sulpiride cycle. These data suggest that the impaired positive feedback effect of estrogen on LH-release in hyperprolactinemic anovulatory women may be caused, at least in part, by disturbed LH-RH release.

Adult↗
PubMed1984

Restoration of LH pulsatility in patients with prolactinomas after trans-sphenoidal surgery.

In hyperprolactinaemic patients with amenorrhoea, pulsatile secretion of LH is reported to be infrequent or absent. For further assessment of the effect of prolactin (Prl) on LH pulsatility, the serum gonadotrophin concentration was determined at 15 min intervals for 180 min in 12 patients with prolactinomas before treatment and in 6 patients who showed normalization of the Prl level after trans-sphenoidal surgery. Surgical treatment caused a significant reduction (P less than 0.05) of the mean (+/- SE) serum Prl level from 519 +/- 152 to 9.2 +/- 1.4 ng/ml. The mean LH level (7.3 +/- 1.2 mIU/ml) before treatment was significantly increased (P less than 0.05) after trans-sphenoidal surgery (12.7 +/- 2.4 mIU/ml). An LH spike was defined as an LH concentration that exceeded the mean LH level over the study period by 2 SD of the intra-assay variation, achieving a level of above 10 mIU/ml. LH spikes were observed in 2 of 12 patients (16.7%) before treatment, and in 5 of 6 patients (83.3%) after trans-sphenoidal surgery, the difference being significant (P less than 0.05). These results suggest that hyperprolactinaemia in prolactinoma patients may cause impaired LH pulsatile secretion and that this derangement can be reversed by reduction of the Prl level by adenomectomy.

Adenoma↗
PubMed1984

[Immunohistological study on the histogenesis and malignant transformation of ovarian mucinous tumors, with special reference to the intestinal metaplasia].

Mucinous tumors of the ovary are generally considered to have a dual origin in histogenesis. Teratomatous elements, however, have recently been reported as appearing in a process of intestinal metaplasia. Malignant transformation has also been felt to occur through intestinalization. To clarify the matter, the relationships among morphological changes in intestinalization, carcinoembryonic antigen and mucus antigens named IMA and M1, which were isolated from intestinal mucosa and ovarian mucinous cyst fluid respectively, were studied in 4 benign, 8 borderline and 6 malignant mucinous tumors of the ovary. Intestinal type and goblet- like cells were sparse, if any, in benign tumors, but conspicuous in borderline and malignant ones. Carcinoembryonic antigen was located in the glycocalyx of intestinal type cells in the benign tumors, but distributed over the entire cytoplasm increasingly with malignancy. These findings lend support to the theory that malignant transformation may occur through intestinal metaplasia in mucous tumors. M1 was positive in many cells of all mucinous tumors, but IMA was shown in some goblet-like cells of a few tumors, regardless of malignancy or the presence of argyrophil cells. These phenomena could be best understood by postulating that IMA was located in the teratomatous intestinal goblet cells of the tumors.

Antigens, Neoplasm↗
PubMed1984

Immunohistological study of isoantigens, carcinoembryonic antigen and human chorionic gonadotropin in adenocarcinomas of the uterus.

Isoantigens, carcinoembryonic antigen (CEA) and human chorionic gonadotropin (hCG) were simultaneously studied by immunohistology in the cervical and endometrial adenocarcinomas. Isoantigen loss was observed in all adenocarcinoma in situ (AIS) of the uterus. However, they appeared again in some tumor cells in 8 of 23 cervical and 4 of 41 endometrial adenocarcinomas. CEA was positive in 1 of 4 AIS and 22 of 23 adenocarcinomas of the cervix. It was distributed continuously in the apical portion and/or in the whole cytoplasm of tumor cells. On the other hand, CEA was positive only in 16 of 41 endometrial adenocarcinomas. It was strongly positive in the squamous elements, but weakly and sparsely in the apical portion and/or in the cytoplasm of some isolated glandular cells which occasionally showed a tendency to squamous differentiation. The majority of neoplastic glands, however, were negative for CEA. HCG was positive in 1 of 23 cervical and 3 of 41 endometrial adenocarcinomas. Two or 3 antigens were found concomitantly in some tumors, but localized differently from each other. It was concluded from the present study that the simultaneous examination of multiple antigens may be useful for characterization of adenocarcinomas of the uterus.

Adenocarcinoma↗
PubMed1983

Reactivity of bovine blood coagulation factor IXa beta, factor Xa beta, and factor XIa toward fluorogenic peptides containing the activation site sequences of bovine factor IX and factor X.

The published activation site sequences of bovine factors IX and X have been utilized to synthesize a number of peptides specifically designed respectively as substrates for bovine factors XIa and IXa beta. The substrates contain a fluorophore (2-aminobenzoyl group, Abz) and a quenching group (4-nitrobenzylamide, Nba) that are separated upon enzymatic hydrolysis with a resultant increase in fluorescence that was utilized to measure hydrolysis rates. Factor XIa cleaved all of the peptides bearing factor IX activation site sequences with Abz-Glu-Phe-Ser-Arg-Val-Val-Gly-Nba having the highest kcat/KM value. The kinetic behavior of factor XIa toward the synthetic peptide substrate indicates that it has a minimal extended substrate recognition site at least five residues long spanning S4 to S1' and has favorable interactions over seven subsites. The hexapeptide Abz-Glu-Phe-Ser-Arg-Val-Val-Nba was the most specific factor XIa substrate and was not hydrolyzed by factors IXa beta or Xa beta or thrombin. Factor IXa beta failed to hydrolyze any of the synthetic peptides bearing the activation site sequence of factor X. This enzyme slowly cleaved four hexa- and heptapeptide substrates with factor IX activation site sequences extending from P4 or P3 to P3'. Factor Xa beta poorly hydrolyzed all but one of the factor XIa substrates and failed to cleave any of the factor IXa beta substrates. Thrombin failed to hydrolyze any of the peptides examined while trypsin, as expected, was highly reactive and not very specific. Phospholipids had no effect on the reactivity of either factors IXa beta or Xa beta toward synthetic substrates. Both factor IXa beta and Xa beta cleaved the peptide substrates at similar rates to their natural substrates under comparable conditions. However the rates were substantially lower than optimum activation rates observed in the presence of Ca2+, phospholipids, and protein cofactors. In the future, it may be useful to investigate synthetic substrates that can bind to phospholipid vesicles in the same manner as the natural substrates for factors IXa beta and Xa beta.

Amino Acid Sequence↗
PubMed1983

Zonal distribution of cytochrome P-450s (P-450(11) beta and P-450scc) and their relation to steroidogenesis in bovine adrenal cortex.

Zona glomerulosa and zonae fasciculata-reticularis of bovine adrenal cortex were separated by our improved method using a remodeled microtome. A considerable amount of fresh mitochondria and microsomes was quickly obtained. Specific content of cytochrome P-450 in the mitochondria was higher in zonae fasciculata-reticularis than in zona glomerulosa. When metyrapone was added to the mitochondria and the drug-induced difference spectra were measured, there appeared two phases in the titration curve; the first phase was saturated at a concentration of 3 microM and the second phase appeared at concentrations higher than 10 microM. The first phase seemed to be due to the substrate-free P-450(11) beta and the second phase to the cholesterol-bound P-450scc. From these spectral studies contents of cytochrome P-450scc and P-450(11) beta were estimated, and those were found to be equal for each zone. From similar studies on substrate-induced difference spectra, there seemed to be no difference between two zones in the affinity of cytochrome P-450(11) beta for deoxycorticosterone and 11-deoxycortisol. This was also the case with 11 beta-hydroxylase activity and substrate specificity for deoxycorticosterone and 11-deoxycortisol.

Adrenal Cortex↗
PubMed1983

Effects of clomiphene citrate on the pituitary gland in chronically estrogenized rat.

Effects of clomiphene citrate (clomiphene) on the pituitary gland of chronically estrogenized ovariectomized rats were investigated. Estradiol-17 beta (E2) pellet implanted subcutaneously in castrated rats for 7 days caused significant increases in pituitary weight and serum prolactin (PRL) level but suppressed serum luteinizing hormone (LH) level. In the estrogenized rats about 40% of estrogen receptor (ER) found in whole pituitary cells (65 +/- 7 fmol/10 mg tissue) was observed in the nucleus, while 60% of ER was present in the cytosol fraction. A single injection of 5 micrograms E2 translocated cytosol ER immediately to nuclear compartment; amounts of ER found in cytosol and nuclear fractions were 16 +/- 1 and 37 +/- 4 fmol/10 mg tissue, respectively, at 1 h. However, the distribution of ER returned to the pre-injection level within 4 h. In the non-estrogenized castrated rats, the nuclear retention of ER was significantly longer than that in the estrogenized rats. A single administration of 200 micrograms clomiphene in the estrogenized rats, on the other hand, increased nuclear ER gradually. Nuclear ER reached the peak level at 4 h (62 +/- 5 fmol/10 mg tissue) and the level remained almost unchanged for 24 h. Cytosol ER decreased and reached a nadir at 4 h (4.3 +/- 0.3 fmol), and the replenishment of cytosol ER could not be detected for 24 h. Similar patterns of cytosol and nuclear ER following the clomiphene injection were also found in the castrated rats. The clomiphene administration in the estrogenized rats resulted in a significant reduction of the pituitary weight 48 h after the administration. The present results seem to show the antiestrogenic action of clomiphene in the pituitary gland.

Animals↗
PubMed1983

Treatment of carcinoma of the uterine cervix by remotely controlled afterloading intracavitary radiotherapy with high-dose rate: a comparative study with a low-dose rate system.

From September, 1974 through December, 1979, a total of 249 patients with carcinoma of the cervix uteri Stage IIb and III were randomly allocated to either remotely controlled high-dose-rate intracavitary radiotherapy or manual afterloading low-dose-rate therapy, with radiotherapy of 20 Gy in 2 weeks to Point A to whole pelvis and 40 Gy in 4 weeks to the parametria. The dose to Point A by intracavitary radiotherapy was 40-60 Gy with one or two fractions in the low-dose-rate group and 30 Gy for the high-dose-rate group by 3 fractions with a once a week schedule. The purpose of this paper is to compare the results between the groups and to clarify the problems in the high-dose-rate group clinically. The local control rate was higher in the high-dose-rate group; however, the complication rate was also higher in this group than in the low-dose-rate group. The dose schedule and the place of rectal dose measurement is discussed. The overall cumulative survival rate was nearly the same in both groups (55% at 5 years), although some difference was noted in each stage. The most common cause of death was distant metastasis outside the pelvis and the second most common was intercurrent disease in Stage IIb and local failure in Stage III.

Brachytherapy↗