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Biomedical subjects

R Iizuka

Publications and source records attributed to R Iizuka.

At least 163 records · Page 9Linked to original sources
PubMed1984

[Amenorrhea due to weight loss].

The cessation of the normal menstrual cycle caused by rapid loss of weight was defined as amenorrhea due to weight loss. All patients developed secondary amenorrhea and 80% of 243 patients were young, unmarried women. More than half of the patients had consciously restricted food intake for cosmetic reasons. LH-RH test revealed that, at onset, the basal levels of LH were low and the LH responses were impaired. The basal and the stimulated levels of FSH were comparable to normal. As the amenorrhea improved, the basal and the stimulated levels of LH rose to the normal range while the FSH responses became greater than normal. There was no significant difference between the rate of weight loss and the responsiveness to LH-RH. The rate of induction of ovulation with clomiphene was 95% of 40 patients with 1st grade amenorrhea, while only 3.9% of 54 patients with 2nd grade amenorrhea ovulated following treatment clomiphene. 80 percent of 19 patients with 2nd grade amenorrhea ovulated following gonadotropin therapy. Within a year after LH-RH stimulation therapy, a resumption of the normal ovulatory cycle or a return to 1st grade amenorrhea was observed in 60%.

Adolescent↗
PubMed1984

[Diagnostic significance of LH-RH two step test in women with normoestrogenic amenorrhea: analysis of the self-priming effect of the anterior pituitary glands].

To investigate the self-priming effect of gonadotropin on the anterior pituitary glands, the response of serum gonadotropins to the "LH-RH two step test" (two step administration of 100 micrograms of synthetic LH-RH at a 60 minute interval) was studied in 20 women with normoestrogenic amenorrhea who were responsive to the progesterone test. The patients were divided into two groups according to the results of the clomiphene test. Blood samples were collected before LH-RH stimulation and 30, 60, 90, 120, 180 minutes after the first stimulation, respectively. The P1P2 ratio (2nd peak level/1st peak level) and delta 1 delta 2 ratio (delta 2/delta 1 = 2nd peak level-60 min. level/1st peak level-0 min. level) of LH and FSH in the clomiphene-positive group were significantly higher than those in the clomiphene-negative group. These ratios are regarded as the degree of the self-priming effect, and at least partially reflect the capacity for the synthesis of pituitary gonadotropins. The results demonstrate that the self-priming effect is more restored in the clomiphene-positive group than in the clomiphene-negative group, and the data also indicate that the analysis of the self-priming effect with the "LH-RH two step test" is useful in developing new diagnostic criteria on ovarian dysfunction.

Adult↗
PubMed1984

[Study on human pituitary gonadotropin synthesis and release in amenorrhea and anovulation by LH-RH two step test].

The pituitary gonadotropin response of synthesis and release to two step stimulation at a 60 minute interval with 100 micrograms of luteinizing hormone-releasing hormone (LH-RH) was studied by radioimmunoassay of hLH and hFSH in the normal menstrual cycle, amenorrhea and anovulation. The definition of delta 1 and delta 2 was as follows: delta 1 = 30 (or 60) min. value-0 min. value. delta 2 = 90 (or 120, 180) min. value-60 min. value. delta 1, delta 2 ratio = delta 2/delta 1. Serum mean levels of hLH in follicular and luteal phase increased after the first injection of LH-RH. The second injection of the hormone induced an increase to above the first peak, indicating the priming effect of the first LH-RH on the second peak. The first peak is presumed to be the pituitary gonadotropin release due to the first injection of LH-RH, and the second peak can be composed in part of hLH newly synthesized by the first LH-RH stimulation. The response of hLH in the ovulatory phase increased after the first administration, but showed no significant peak after the second. The LH-RH two step test in normoestrogenic and PCO type amenorrhea produced two peaks of the mean levels of hLH. In ovarian anovulation, an hLH value higher than the others was detected before the first LH-RH stimulation. The first injection caused an increase in serum hLH but after the second there is no significant peak. In contrast, serum hLH and hFSH values were lower than in the normal menstrual cycle.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

[Rapid measurement of estriol & estradiol by high performance liquid chromatography (HPLC)].

Measurement of Estriol (E3) and Estradiol (E2) within 25 minutes by high performance liquid chromatography (HPLC) was achieved in this study and the values were compared with those of radioimmunoassay (RIA). A totally computerized HPLC method was developed for measuring unconjugated E3 and E2 in the sera of pregnant women. The sera samples were injected directly into the apparatus and transferred to a pretreatment column where estrogens were absorbed while hydrophilic components such as proteins and carbohydrates were excluded. The estrogens then passed through another separation column containing a new type of polymer gel. The mobile phase consisted of an acetonitrile/water mixture, and separation was achieved by means of a reversed phase mechanism. The eluent was monitored for fluorescence. All these procedures were monitored and controlled with a built-in microcomputer. The sera samples from 61 normal pregnant women at 20 to 41 weeks of pregnancy were simultaneously assayed by HPLC and RIA. The correlation of values obtained from HPLC and RIA was; E3: Y = 0.875X-0.172, the coefficient of correlation was 0.899, E2: Y = 0.972X + 6.791, the coefficient of correlation was 0.841 (Y = RIA values, X = HPLC values). The quick measurements of E3 and E2 by HPLC can be a useful method in evaluating the feto-placental function.

Chromatography, High Pressure Liquid↗
PubMed1984

Immunoreactive oxytocin in human placental tissue.

Immunoreactive oxytocin was detected with the aid of specific and sensitive assay in a supernatant obtained after homogenization of human placenta. It was found that: 1. The content of immunoreactive oxytocin increased from 30 ng per placenta at first trimester to 4.8 micrograms at second trimester and 15 micrograms at third trimester; 2. The mean immunoreactive oxytocin concentration in 1 g of the placental tissue was 2.5 ng g-1 at first trimester and then it significantly increased to 34 ng g-1 at second and third trimester; 3. The dilution curve of placental tissue was nearly parallel to that of synthetic oxytocin; 4. The elution curve of placental tissue through CMC column chromatography showed similar pattern with that of synthetic oxytocin. Though the hypothalamus and the posterior pituitary have been known as major sources of oxytocin, these data indicate that the placenta might be the third source of this hormone.

Chromatography, Ion Exchange↗
PubMed1983

Effects of tyrosine administration on serum biopterin in normal controls and patients with Parkinson's disease.

After administration of tyrosine, total concentration of biopterin, the cofactor for tyrosine hydroxylase, was increased in the striatum, adrenal glands, and serum of rats, and in the serum of humans. Serum biopterin is lower in patients with Parkinson's disease than in normal controls. After oral administration of tyrosine, the increase in serum biopterin concentration was smaller in patients with Parkinson's disease (less than twofold) than in healthy controls (three-to sevenfold). These results suggest that tyrosine may have a regulatory role in biopterin biosynthesis and that patients with Parkinson's disease may have some abnormality in the regulation of biopterin biosynthesis.

Administration, Oral↗
PubMed1983

Effect of prostaglandin D2 on gonadotropin release from rat anterior pituitary in vitro.

A new prostaglandin D2 (PGD2), which is highly concentrated in the rat hypothalamic-pituitary system, was investigated for its gonadotropin release and synthesis by radioimmunoassay (RIA). Significant increases in the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were observed when the anterior pituitaries were incubated for 4 hours in vitro in the presence of 500 micrograms PGD2/ml incubation medium. Little change in LH and FSH contents in the rat anterior pituitary was observed between the control and PGD2-stimulated groups during incubation. In addition, more than 200 micrograms PGD2/ml induced a marked increase of cyclic adenosine 3',5' monophosphate (cAMP) formation in the rat anterior pituitary, and this was observed within 10 minutes after stimulation by PGD2. These data indicate that PGD2 directly induces a marked release of both LH and FSH from the gonadotrophs, and the mechanism of action of PGD2 could be mediated by cAMP formation.

Animals↗
PubMed1983

Separation of human X- and Y-bearing sperm using percoll density gradient centrifugation.

Human X- and Y-bearing sperm, which were detected by the quinacrine mustard fluorescent staining method, were separated in density gradient centrifugation using Percoll (Pharmacia Fine Chemicals, Uppsala, Sweden). The apparent percentages of Y-bearing sperm in normo- and oligospermia were 46.7% +/- 3.4% (n = 13) and 46.6% +/- 1.2% (n = 10), respectively. The separation was observed to some extent in Ficoll Paque (Pharmacia Fine Chemicals); then it was further achieved using Percoll. After centrifugation, sperm were distributed widely on various interfaces of the discontinuous Percoll density gradient (1.06 to 1.11 gm/ml). The content of Y-bearing sperm in the fraction lighter than 1.06 gm/ml was 73.1% +/- 3.3% and was reduced gradually along the density increment. Finally, it was found to be 27.4% +/- 3.4% in the sediment (more than 1.11 gm/ml).

Adult↗
PubMed1983

Levels of inhibin-F activity and steroids in human follicular fluid from normal women and women with polycystic ovarian disease.

To examine inhibin-F activity (FSH-suppressing activity) in human follicular fluid of polycystic ovary (PCO) patients, 13 follicles from 5 documented PCO patients and an additional 31 follicles from normal women in the follicular phase of the menstrual cycle were sampled, and inhibin-F activity was measured in rat anterior pituitary cell cultures. Inhibin-F activity was measured in follicular fluid after stripping steroids from the fluids using treatment with dextran and activated charcoal. Estrogen, progesterone, and delta 4-androstenedione in the follicular fluid were also determined by RIA. Estrogen and progesterone levels in follicular fluid from PCO follicles 3.9 +/- 0.34 mm in diameter were comparable with those in follicular fluid obtained from viable follicles (which had a delta 4-androstenedione to estrogen ratio of 10 or less) from normal women. delta 4-Androstenedione levels in PCO follicles were higher (P less than 0.01) than those in viable and atretic follicles of normal women. Inhibin-F levels in PCO follicles were comparable to those in viable follicles, but significantly greater (P less than 0.01) than levels in atretic follicles of normal women. If inhibin-F levels in both atretic and viable follicles of normal women were pooled, the levels were less (P less than 0.05) compared to the level in PCO follicular fluid. As an additional control, follicular fluid was collected from 90 follicles of normal women throughout the menstrual cycle, and follicular size was determined as well as inhibin-F and steroid content. Small follicles less than 8 mm; (comparable in size to the PCO follicles examined) obtained at each stage represented 79%, 24%, 0%, and 94% of the total follicles obtained in the early to midfollicular, late follicular, preovulatory, and luteal phases of the cycle, respectively. Inhibin-F activity in the fluids of these follicles was less than that in PCO follicular fluid. The average inhibin content of all of the small normal follicles was 197 +/- 34 U/10 microliter, which was significantly less (P less than 0.05) than the level in PCO follicles (332 +/- 13 U/10 microliters). These data represent the first observation of inhibin-F activity in PCO follicular fluid and suggest the possibility of involvement of inhibin-F in bringing about low or normal basal levels of FSH in the presence of elevated basal LH levels often observed in PCO patients.

Animals↗
PubMed1983

Detection of immunoreactive human placental oxytocin and its contractile effect on the uterine muscle.

Freshly obtained human placentas from various periods of gestation were quantitatively analysed for their immunoreactive oxytocin (OT) content and its biological activity was examined in a Magnus apparatus by utilizing rat uterus. The mean values for placental immunoreactive OT per gram tissue increased from the first to the second trimester, maintaining its high level to term. The total content of placental OT also increased continually from the beginning of pregnancy to term. Blood levels of estrogen stimulated neurophysin (ESN) and OT were concomitantly enhanced through gestation. Placental extract and synthetic OT showed similar peaks in the elution pattern of ion-exchange chromatography through a carboxymethyl cellulose column. Synthetic OT and placental extract induced marked uterine contraction in diestrous rats. However placental extract previously incubated with OT antiserum failed to induce this effect. Though detection of immunoreactive OT by immunoassay alone does not provide definite identification of pituitary and placental OT, the present study suggests that placental immunoreactive OT could have a contracting effect on the uterine muscle.

Animals↗
PubMed1983

[Response of subunits of human pituitary gonadotropins to LH-RH 2 step stimulations in ovarian dysfunction].

To investigate the alteration of pituitary gonadotropin subunits in ovarian dysfunction by two step administration of LH-RH at 60 minutes interval, specific and sensitive radioimmunoassays of the subunits were utilized for this study. Blood samples were obtained from thirteen women of ovarian dysfunction and from fifteen normal women of subunits. The definition of delta 1 and delta 2 was as follows. delta 1(hormone release) = 30 (or 60) min value-0 min value. delta 2(hormone synthesis and release) = 90 (or 120, 180)-60 min value. delta 1 delta 2 ratio = delta 2/delta 1. Correlation was observed between the value of native gonadotropic hormones and the value of their subunits (LH-alpha and LH-beta) in normal women but no correlation was detected in delta 1 and delta 2 values in ovarian dysfunction. Thus LH-RH 2 step test suggest the possibility to differentiated pituitary function in both normal and abnormal subjects. The analysis of gonadotropin subunits was useful to develop new diagnostic criteria of ovarian dysfunction.

Adult↗
PubMed1983

Cytochemical study of steroid-producing activities of human oocytes.

The aim of this study was to determine whether steroidogenesis occurs in human immature oocytes aspirated from follicles during gynecologic laparotomy. delta 5-3 beta-Hydroxysteroid dehydrogenase (delta 5-3 beta-HSD) and 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) activities were detected by Dickmann and Dey's reaction medium consisting of 1.8 mg substrate (pregnenolone or 17 beta-estradiol [E2]), 4 mg nicotinamide-adenine dinucleotide, 2 mg nitro-blue tetrazolium, 10 ml 0.1 M phosphate buffer. The activity of adenylate cyclase was examined by ultrastructural-cytochemical study using 5'-adenylyl-imidodiphosphate (AMP-PNP) as a substrate in Vorbrodt's medium of 0.005 M AMP-PNP, 0.001 M MgCl2, 0.02 M SrCl2, 0.01 M NaF, 0.002 M theophylline, 0.01 M Tris-HCl. Furthermore, in indirect immunofluorescence study, the presence of endogenous progesterone and E2 and the activity of delta 5-3 beta-HSD were demonstrated. The results suggest that steroidogenesis, through the adenylate cyclase-cyclic adenosine 3':5'-monophosphate system, in human oocytes may play some important role in oocyte maturation, fertilization, and early embryonic development. The implication of steroid-producing activities of the human oocytes for cytoplasmic maturation is discussed.

17-Hydroxysteroid Dehydrogenases↗
PubMed1983

[Study on immunoreactive oxytocin in the human placental tissue].

Immunoreactive oxytocin in the human placenta was detected by the following procedure. The fresh placenta of each trimester was rinsed with cold normal saline, then homogenized. Its supernatant was assayed for oxytocin by sensitive and specific radioimmunoassay and the dilution curve of the placental tissue was plotted on the dose response curve of synthetic oxytocin. Through carboxy methyl cellulse (CMC) column chromatography the supernatant of the homogenate was eluted and was compared with that of synthetic oxytocin. The results are as follows: 1) The placental tissue content of immunoreactive oxytocin increases from 30ng/placenta at first trimester to 4.8 micrograms at second trimester, 15 micrograms at third trimester, respectively. 2) The mean immunoreactive oxytocin concentration of 1gm of the placental tissue is 2.5ng/gm at first trimester the significantly increases to 34ng/gm at second trimester maintaining the level till third trimester. 3) The dilution curve of placental tissue nearly parallels that of synthetic oxytocin. 4) The elution curve of placental tissue through CMC column chromatography shows similar pattern compared to that of synthetic oxytocin. Though the hypothalamus and the posterior pituitary gland have been known as major sources of oxytocin, these data indicate that the placenta might be the third origin for oxytocin.

Female↗