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Biomedical subjects

A Imai

Publications and source records attributed to A Imai.

At least 181 records · Page 10Linked to original sources

Acardiac acephalic monster extremely larger than its co-twin. A case report.

The acardiac monster represents a rare but one of the severest congenital anomalies which occur only in multiple pregnancy. The affected fetus is sustained by a parasitic anastomosis to the umbilical blood vessels of the normal fetus. We report an interesting case of a macrosomic acardiac acephalic fetus weighing 4.5-fold of another variable donor fetus (approximately 6 kg) in a twin pregnancy.

Abnormalities, Multiple↗

Different effects on oestrogen binding sites and anti-oestrogenic action of danazol and progesterone.

Rabbit uterus contains type I and II oestrogen binding sites in the cytosol, and nuclear fractions. Oestrogen-stimulated increase in uterine weight was inhibited by concurrent treatment with progesterone or danazol. Oestrogen-induced type I binding sites were decreased by progesterone and to a lesser extent by danazol, while oestrogen-induced type II sites were decreased almost equally in the two groups. Neither progesterone nor danazol alone caused any detectable changes in uterine weight. These findings may suggest that the anti-oestrogenic effect on uterine weight is more correlated with the change in type II binding sites of oestrogen than that in type I sites. Thus, danazol may exert anti-oestrogenic actions through a pathway independent from that of progesterone.

Animals↗

Effects of overt and covert tasks on orienting response under unimodal and bimodal stimulations.

The present study examined the occurrences of "selective" and "alertive" orienting responses (ORs) in relation to stimulus modality under overt and covert tasks by using electrodermal response (EDR). Two sets of 36 university students received two stimuli (figure and/or toe) during both habituation and test sessions either unimodally (Exp. I) or bimodally (Exp. II). The subjects were assigned to one of three groups during a test session: (1) Key-press which required pressing a key at the offset of the test stimulus, (2) Perceptual-judgment which requested estimating the duration of the test stimulus, or (3) Neutral-instruction which received no task for stimulus presentation. Analysis showed in Exp. I, the first two groups indicated significant increases in EDR magnitudes only in response to the test stimulus, and this EDR increase demonstrated the occurrence of selective OR. In Exp. II, key-press alone showed a significant increase in EDR magnitudes to the nontest stimulus, and this EDR demonstrated the elicitation of alertive OR. The alertive OR emerged clearly when the subject perfored an overt task under binodal stimulation.

Adolescent↗

Suppression of growth-promoting activity in extract from human uterine cancer by cyclic AMP-mediated mechanism.

Uterine cervical and corpus cancers have been reported to synthesize and secrete the putative peptide mitogen, which elicits a potent proliferative response in the fibroblasts [Res. Commun. Chem. Pathol. Pharmacol. 66, 477-480 (1989)]. The extract from human cervical cancers stimulated [H]thymidine incorporation into human endometrial fibroblasts in a dose-dependent manner. Concomitant exposure of the fibroblasts to dibutyryl cyclic AMP (cAMP) of forskolin, the mitogenic activity of the extract was suppressed by 60%. A higher concentration of the extract did not overcome the inhibitory effects of them, implying that they acted at a stage after the mitogen in extract and specific receptor interaction. These results demonstrated that the growth-promoting activity in cervical cancer extract could be under negative control through cAMP-dependent mechanism.

Bucladesine↗

Possible evidence that dehydroepiandrosterone sulfate (DHA-S) stimulates cervical ripening by a membrane-mediated process: specific binding-sites in plasma membrane from human uterine cervix.

Fetal adrenal steroid, dehydroepiandrosterone sulfate (DHA-S) is well known to promote cervical ripening in late pregnancy. The presence of sites specifically binding the DHA-S in plasma membrane was studied in human cervical fibroblasts prepared from pregnant uterus. The fibroblasts were incubated with [3H] DHA-S and then fractionated into plasma membranes, cytosol, nuclei, and other organella debris. The specific activity of 3H-count in the plasma membrane fraction was enriched approximately 7-fold compared with the whole homogenate. When the isolated plasma membrane preparations from the fibroblasts were exposed to [3H] DHA-S, the binding showed saturation kinetics; an apparent equilibrium dissociation constant (Kd) of 12 nM, and the binding capacity (Bmax) of 1.25 pmol/mg protein. The present results suggest that DHA is bound to and recognized by components in plasma membrane, and may exert its action on cervical ripening through the membrane-mediated processes.

Binding Sites↗

[A case of rheumatoid arthritis complicated with auranofin-induced acute interstitial pneumonitis].

A case of auranofin(AF)-induced acute interstitial pneumonitis in a patient with rheumatoid arthritis (RA) is reported and possible mechanism of the incidence is discussed. A 57 year-old woman with a history of RA starting in early April 1989, had been prescribed AF for seven days prior to her referral to this hospital. Because of the severity of her polyarthritis, AF was discontinued; therapy with gold sodium thiomalate (GST) instead was started on 23 June 1989. The patient responded quite favorably. At a total cumulative dose of 160mg of GST, however, she developed generalized exfoliative dermatitis and the drug was discontinued. On 29 Sept. 1989 when her skin lesions cleared up completely, she was put on AF again. Six days after resumption of AF therapy, she developed fever. Nonproductive cough and dyspnea on exertion was observed within the following three days. The chest X-ray film revealed diffuse reticular-linear infiltrates more prominently in both upper lobes. Arterial blood gas studies showed hypoxemia and a restrictive ventilatory defect was demonstrated by pulmonary function studies. AF was stopped. High dose pulse iv corticosteroid(CS) therapy combined with oral CS was instituted. Immediate improvement of both subjective and objective findings was observed. By using the patient's peripheral blood lymphocytes, delayed lymphocyte stimulation test(DLST) against the probable causative agents was performed before the bolus CS therapy. Stimulation Index(shown in percentage) was markedly elevated in AF(724%) as compared with GST(163%). The fiberoptic bronchoscopy with bronchoalveolar lavage(BAL) was performed. Analysis of BAL fluid revealed increased cellularity (9 x 10(5)/ml) with marked lymphocytosis of 79%.(ABSTRACT TRUNCATED AT 250 WORDS)

Arthritis, Rheumatoid↗

Changes in the prolactin response to thyrotropin-releasing hormone (TRH) throughout the proliferative phases in the ovulatory and anovulatory menstrual cycle.

This study was undertaken to determine the changes of prolactin (PRL) response to thyrotropin-releasing hormone (TRH) throughout the menstrual cycle. The infertile patients with normal ovulatory menstrual cycle and with normoprolactinemic anovulatory cycles were assigned to intravenous loading tests with TRH (0.5 mg) and gonadotropin-releasing hormone (Gn-RH)(0.1 mg) during the proliferative phase of the cycle. In normal ovulatory patients, the basal PRL and gonadotropin levels did not significantly vary, while the response to TRH was reduced to late proliferative phase, compared to early and mid-phases. The response of luteinizing hormone (LH), but not follicle-stimulating hormone (FSH) was approximately 2-fold higher in the late proliferative phase than in early or mid-phases. In patients with normal PRL and high LH (over 8 mIU/ml), both basal levels and responses to Gn-RH of the gonadotropins were higher than those in the normal ovulatory cycle, but PRL profiles was essentially equal to those in the late proliferative phase of normal cycle. No significant differences of basal and stimulated levels of gonadotropins and PRL were observed in patients with normal PRL and LH levels. Thus PRL response rather than basal level may be related to gonadotropin secretion and consequently menstrual cycle.

Adult↗

Direct interaction between human endometrial carcinoma and fibroblast: fibroblast-derived growth factor.

Epithelial-stromal interaction was investigated in human endometrial carcinoma. The medium cultured with fibroblasts derived from human endometrial carcinoma tissue increased [3H]thymidine incorporation into and estrogen receptor level of endometrial carcinoma (Hashimoto) cells. Concomitant exposure to estradiol, but not to progesterone, synergistically enhanced the conditioned medium-induced events. These findings demonstrated direct interaction of epithelial cells and its stromal cells in endometrial carcinoma.

Adenocarcinoma↗

Inhibitory action of estradiol on growth promoting activity in extract from uterine cancers.

Extracts from uterine cervical and body cancers, but not from benign tumor or intact tissues tested, were found to contain a growth-promoting activity which induced the proliferation of human endometrial fibroblasts. Exposure of cultured fibroblasts to the cancer extracts increased the rate of [3H]thymidine incorporation in a dose-dependent manner. The activity was heat-labile, and not inactivated by removal of lipid-soluble material suggesting that the activity is associated with a protein. When the fibroblasts were preincubated with estradiol for 12 hours, but not for 1 hour, the extract-induced fibroblast proliferation was suppressed. The inhibitory effect of estradiol was dose related (EC50: 10nM) and non-competitive, suggesting that the steroid may reduce the sensitivity of fibroblasts to the extracts. This is the first report to provide direct evidence that estradiol may play an inhibitory role in the action of growth factor-like peptide produced from malignant tumors.

Cell Division↗

Evidence for tight coupling of phospholipase activation and Ca2+ influx during acrosome reaction of golden hamster spermatozoa.

1. Phospholipases have been proposed to play a key role in sperm acrosome reaction. To examine the activation mechanism of phospholipases and subsequently sperm fertilizing capacity. Ca2+ fluxes and phospholipid turnover (breakdown and synthesis) were investigated in golden hamster spermatozoa during acrosome reaction. 2. Upon exposure of the spermatozoa to 1.7 mM Ca2+, a net uptake by the cells occurred in two distinguishable phases. 3. Depletion of extracellular Ca2+ by ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) at a time that an initial Ca2+ uptake was observed to reach almost steady-state, prevented the secondary Ca2+ uptake and acrosome reaction. 4. The time course of an initial Ca2+ uptake seemed to precede that of the acrosome reaction. 5. Incubation of the spermatozoa with Ca2+ in the presence of [3H]glycerol induced a rapid increase in labeling of phosphatidic acid, a key intermediate of phosphinositide turnover initiated by the action of phospholipase C, which appeared to parallel the time course of a first phase of Ca2+. 6. Phospholipase A2 activation, detected by lysophospholipid formation, slightly delayed the initial events of first Ca2+ uptake and phosphatidic acid production. 7. It is concluded that first Ca2+ entry into the cells, associated with phosphatidic acid production, activates a phospholipase A2, leading to the production of substances, like lysophospholipids and fatty acids, which may contribute to acrosome reaction.

Acrosome↗

Effects of estradiol-17 beta and estriol on their binding sites in the rabbit uterus.

1. Receptors for estradiol-17 beta (E2) and estriol (E3) were detected in the rabbit uterus. 2. Saturation analysis of estrogen binding sites in the cytosol showed that the dissociation constants of E2 and E3 for the high affinity binding sites were 1.8 +/- 0.5 nM and 2.3 +/- 0.3 nM, respectively, when dextran-coated charcoal was used to isolate free and bound ligands. 3. To eliminate non-specific (cross) bindings to their receptors, effects of unlabeled E2 and E3 on [3H]E3 and [3H]E2 bindings was examined. 4. [3H]E2 cytosol binding was observed to be specific for E2 and [3H]E3 cytosol binding was more specific for E3. 5. E2 priming to rabbits increased the binding sites for both E2 and E3, which was also more potent than E3 priming. 6. Moreover, the increase in E2 binding sites was greater than that in E3 binding sites. 7. These findings may suggest that there are separate binding sites for E2 and E3 in rabbit uterus and that synthesis of their binding sites is regulated by E2 but not E3.

Animals↗

Phospholipase C in human endometrial fibroblasts and its regulation by estrogens.

1. Stimulated inositolphospholipid turnover has been proposed as a signal-transducing mechanism in many cell types. It appears to be initiated by stimulation of hydrolysis of inositolphospholipid by a phospholipase C. 2. In human endometrial fibroblasts, estradiol was observed to cause sequential enhancement of [32P]phosphate incorporation into phosphatidic acid (PA) and phosphatidylinositol (PI), indicating an accelerating effect of estradiol on inositolphospholipid turnover. Specific 32P-radioactivity in the gamma-phosphate of ATP was increased in response to estradiol. Estrone or estriol were without any effects. 3. To investigate possible mechanisms by which estradiol activates a phospholipase C enzyme in the fibroblasts, the plasma membrane fraction isolated from the fibroblasts was exposed to estradiol in the presence of guanosine triphosphate (GTP) to detect inositol trisphosphate (IP3) production. The IP3 production was Ca2+ dependent, a dependency not affected by estradiol. 4. However, ATP decreased the Ca2+ concentration required for IP3 production in a dose-dependent manner; adenosine diphosphate (ADP), cytidine triphosphate (CTP) showed no effects. 5. These findings from cell and cell-free systems might suggest that estradiol stimulates a phospholipase C, as a result of enhancement of intracellular ATP synthesis, but not as a result of a direct effect on the enzyme molecule or direct activation of receptor-phospholipase C unit. 6. This may give us new insight into estrogen-stimulated cellular phenomenon through some mechanisms other than that classically associated with the action of estrogen.

Adenosine Triphosphate↗

Possibility of anti-estrogen action from estriol specific binding sites in rabbit uterus.

1. This study was designed to investigate the clomiphene or tamoxifen binding to receptor sites for estradiol-17 beta (E2R) and estriol (E3R) in the rabbit uterus. 2. Those so-called anti-estrogenic compounds tended to inhibit E2-E2R and E3-E3R bindings equally. 3. The inhibitor constant of clomiphene for E2R was approximately 3.8 x 10(-8) M at 4 degrees C and that for E3R approximately 1.8 x 10(-8) M at 4 degrees C in a given case, determined by charcoal assay. 4. It is suggested that the anti-estrogenic compounds demonstrate their effects after binding either to E2R or to E3R. 5. There were some tissue differences of the contents between E2R and E3R. For example, the uterus and the cortex contained E2R, and the pituitary E3R more than the other.

Animals↗

[Two cases of rheumatoid arthritis complicated with vasculitis-induced ischemic enterocolitis].

Episodes of catastrophic entero-colitis associated with mesenteric vascular insufficiency in patients with rheumatoid arthritis(RA) have rarely been recorded thus far. We herein report two cases of RA complicated with severe attacks of entero-colitis presumably due to mesenteric vasculitis. Surgical intervention was necessary in the first case, while the second patient recovered well only through conservative therapy. Case 1: A 74-year-old man with history of RA since 1985 started to complain of abdominal discomfort and nausea early in February, 1989. On February 12, Episodes of tarry stool developed. Rapid down-hill clinical course prompted laparotomy under the clinical diagnosis of peritonitis. Ischemic changes were observed at the ileum end, the entire length of which was 120 cm orally from the cecum. The site was resected. Multiple linear and aphthoid ulcer lesions were discovered throughout the entire lumen. Histopathologically, evidence of necrotizing vasculitis such as fibrinoid necrosis and mural thrombi was demonstrated in small arteries of the submucosal layer underlying the ulcer lesion. Case 2: A 63-year-old woman who had been suffering from RA since 1980 noticed the onset of nausea, abdominal pain and bloody diarrhea in July, 1989. Colonoscopy examination revealed multiple linear and aphthoid ulcers in the sigmoid colon which was presumed to be due to ischemia. Laboratory evaluation at that time demonstrated hypocomplementemia, positive circulating immune complex and high titer of anti-DNA antibody. Corticosteroid therapy with moderate dose was successful in alleviation of all the abnormal findings and the patient fully recovered three months after her initial GI episode.

Aged↗

Acute pseudo-obstruction of the colon (Ogilvie's syndrome) during pregnancy.

A case of colonic pseudo-obstruction (Ogilvie's syndrome) during pregnancy is described. The patient, with placenta previa, was in management of bleeding and also of premature labor. She was successfully treated with conservative measures for the Ogilvie's syndrome, and thereafter underwent a cesarean section only. There had been no recurrence of the pseudo-obstruction after the surgical procedure.

Acute Disease↗