Systematics of fusion-fission time scales.
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Journal Article↗
Biomedical subjects
H Okamura
Publications and source records attributed to H Okamura.
Endotoxin-induced serum factor that stimulates gamma interferon production.
Serum from Mycobacterium bovis BCG-infected mice that had been challenged with lipopolysaccharide (LPS) exhibited a marked ability to induce gamma interferon (IFN-gamma) in cultures of spleen cells of normal mice in the presence of interleukin-2 (IL-2). The inducing activity became detectable in the circulatory system about 90 min after LPS challenge, disappeared at around 5 h, and was observable upon 640x dilution of the serum. Addition of monoclonal anti-IL-2 receptor antibody to the culture inhibited the induction by the serum. The activity induced high levels of IFN-gamma even in nylon wool-nonadherent cells, while concanavalin A failed to do so. Serum from uninfected mice challenged with LPS contained no such activity. The molecular weight of the active substance, estimated by gel filtration, was about 70,000. There were pronounced differences among mouse strains in the activities of the sera prepared, which paralleled the amounts of IFN-gamma produced in vivo. However, the levels of IFN-gamma produced in whole spleen cells and in nylon wool-nonadherent cells from mice of various strains were the same when stimulated with competent serum. These results indicate the existence of an unidentified factor that induces IFN-gamma in cooperation with IL-2 in macrophage-depleted splenocytes. They also suggest that IFN-gamma production in vivo is not genetically controlled at the lymphocyte level but, rather, at the level of synthesis of the unknown factor.
Animals↗
Increase in ovarian leukotrienes during hormonally induced ovulation in the rat.
The ovulatory process was initiated in 25-day-old Wistar rats by injecting human chorionic gonadotropin (hCG; 10 IU sc) 2 days after the animals had been primed with pregnant mares serum gonadotropin (PMSG; 10 IU sc). By 4 h into the ovulatory process, leukotriene (LT) B4 increased 2-fold (P less than 0.001) and LTs C4/D4/E4 increased 1.3-fold (P less than 0.002). By the time of ovulation (10-12 h after the administration of hCG) both eicosanoids declined to their pre-hCG levels. When animals were treated with the cyclooxygenase inhibitor indomethacin at the specific dose of 0.316 mg/rat sc at 1 h before hCG, the ovarian levels of LT B4 and LTs C4/D4/E4 increased to 210% (P less than 0.01) and 113% (P less than 0.05), respectively, above the control levels at 4 h after hCG. Concomitantly, this dosage of indomethacin reduced ovarian prostaglandins (PGs) E and F by 99% (P less than 0.001) and 98% (P less than 0.001), respectively, and it reduced the ovulation rate by 76% (P less than 0.001). Thus it appears this dose of indomethacin blocked the conversion of ovarian arachidonic acid into PGs and shunted this substrate into the lipoxygenase pathways that lead to LT formation. In conclusion, the moderate increase in ovarian LTs is characteristic of inflammatory reactions, and, therefore, these data support the hypothesis that the biochemical events of ovulation resemble an inflammatory process.
Animals↗
Characterization and applications of monoclonal antibodies to the prolactin receptor.
Monoclonal antibodies (mAbs) were produced in BALB/c mice immunized with partially purified PRL receptors from rat liver. Two mAbs (T1 and T6) were able to completely inhibit [125I]ovine PRL ([125I]oPRL) binding to solubilized rat liver PRL receptors, while two other mAbs (U5 and U6) showed only a small effect on PRL binding, but were able to precipitate hormone-receptor complexes. Scatchard analysis of [125I]oPRL binding to rat liver microsomes in the presence of mAbs resulted in a decrease in the number of sites without changing the affinity of PRL binding by T1 and T6, whereas U5 and U6 altered neither parameter. [125I]mAb binding to rat liver microsomes was performed in the presence of various concentrations of unlabeled mAbs or oPRL to examine the interaction between mAbs. Competition of binding to the receptor was observed, respectively, between T1 and T6, U5 and U6, and U5 and E21 (a mAb to the rat liver PRL receptor previously produced). Both [125I]T1 and [125I]T6 binding were inhibited by oPRL, although not completely (80% inhibition at the higher concentrations). When [125I]T1 binding was analyzed by Scatchard analysis, two classes of binding sites to rat liver microsomes were found, of which only the number of higher affinity sites was affected by the presence of oPRL in incubation. Similar results were observed for [125I]T6 binding. [125I]mAb binding to microsomes from other tissues and species was examined. All five mAbs were able to bind to microsomes from rat tissues (liver, ovary, adrenal, prostate, and Nb2 lymphoma cells), similar to the level of [125I]oPRL binding in these tissues. The binding characteristics of [125I]T6 or [125I]U5 were essentially identical in all rat tissues examined. Although T1, U6, and E21 showed strong species specificity, there was significant binding of T6 to rabbit liver and mammary gland and of U5 to rabbit and pig mammary gland and mouse liver Competition curves of [125I]U5 binding were parallel for rat, rabbit, and mouse tissues, while [125I]T6 binding was able to distinguish PRL receptors in rabbit mammary gland from those in rat tissues. The use of 125I-labeled mAb in immunoblot analysis of the PRL receptor resulted in a marked increase in sensitivity. All mAbs detected microsomal PRL receptors in rat liver with mol wt of 84,000, 42,000 and 40,000. As little as 4 fmol receptors can be identified using this approach. Microsomal PRL receptors from rat ovary, prostate, and Nb2 cells and purified receptors from pig and rabbit mammary gland were subjected to immunoblot analysis.(ABSTRACT TRUNCATED AT 400 WORDS)
Animals↗
Increase in ovarian 15-hydroxyeicosatetraenoic acid during ovulation in the gonadotropin-primed immature rat.
The ovarian level of 15-hydroxyeicosatetraenoic acid (15-HETE) was measured by RIA during ovulation in gonadotropin-primed immature Wistar rats. The ovulatory process was initiated in 25-day-old rats by a 10-IU injection of hCG sc 2 days after the animals had been primed with 10 IU PMSG, sc. Ovarian follicles begin to ovulate 10 h after hCG. At 0 h after hCG, the ovarian 15-HETE level was 0.6 +/- 0.2 ng/mg ovarian protein. At 6 h the 15-HETE level increased sharply to 27.3 +/- 4.2 ng/mg protein and reached a peak of 50.0 +/- 9.8 ng/mg protein at 10 h. Ovarian 15-HETE decreased significantly between 10-16 h after hCG (when ovulation was essentially completed). The pattern of secretion of this 15-lipoxygenase product was reciprocal to the pattern of secretion of leukotriene-B4 by the rat ovary. Ovarian 15-HETE production and ovulation were inhibited in a dose-dependent manner when indomethacin was administered sc 1 h after hCG in doses ranging from 0.10-10.0 mg/rat. In contrast, the synthesis of ovarian prostaglandins-E and -F was inhibited by a dose of indomethacin as low as 0.0316 mg/rat, but this dose did not significantly affect the ovarian 15-HETE level or the ovulation rate. Therefore, the ovulation rate was more closely correlated with the ovarian 15-HETE level (P less than 0.001) than with the ovarian levels of either prostaglandin-E or -F (0.10 greater than P greater than 0.05). The results suggest that products of the 15-lipoxygenase pathway of arachidonic acid metabolism may be important in the biochemical events of mammalian ovulation.
Animals↗
Multiple regulation of prolactin receptor gene expression in rat liver.
Sex steroids are major regulators of PRL receptor expression in rat liver. Using a probe encoding the rat PRL receptor we have studied receptor mRNA levels in female rat liver during ontogeny and in response to estrogen treatment. Steady state mRNA levels were determined by Northern blot and densitometric analysis. Messenger RNA levels have been compared to the number of binding sites, which was assessed by Scatchard analysis of [125I]ovine PRL binding in membrane preparations. Our results show that steady state mRNA and binding levels of PRL receptors are both regulated by development and estrogens, but that binding does not exactly parallel mRNA levels. From the developmental stages of prepuberty to adult, receptor numbers increase 8-fold, whereas mRNA levels increase 3-fold. Estrogen treatment stimulates receptor levels 6-fold, but mRNA levels are only increased 3-fold. These results suggest that PRL receptor gene expression in rat liver is regulated at the transcriptional or posttranscriptional level as well as at the translational level.
Animals↗
Increase in ovarian kallikrein activity during ovulation in the gonadotrophin-primed immature rat.
The ovulatory process was initiated in 25-day-old rats by injecting them with hCG (10 i.u., s.c.) 2 days after the animals had been primed with PMSG (10 i.u., s.c.). At 2-h intervals after hCG, the ovaries were extracted and assayed for glandular kallikrein activity by using a chromogenic substrate (H-D-Val-Leu-Arg-p-nitroanilide) which exhibits optical density (at 405 nm) upon hydrolysis. In 0-h control ovaries the activity was 12.5 x 10(-3) kallikrein units (KU)/mg protein and it increased to a peak of 56.6 x 10(-3) KU/mg at 12 h after hCG, when the follicles first began to rupture. The kallikrein activity was distinguishable from ovarian plasminogen activator activity on the basis of pH optima and response to trypsin inhibitor (SBTI). The activity was inhibited by a s.c. dose of indomethacin of 0.3 mg/rat, or higher, and this dosage inhibited ovulation. The results suggest that kallikrein activity contributes to the degradation of Graafian follicles during ovulation in mammals.
Animals↗
Case studies on the effect of exercise and hot water submersion on intracardiac temperature and the performance of a pacemaker which varies pacing rate based on temperature.
The effectiveness of using blood temperature change as an indicator to automatically vary heart rate physiologically was evaluated in 3 patients implanted with Model Sensor Kelvin 500 (Cook Pacemaker Corporation, Leechburg, PA, USA) pacemakers. Each patient performed two block-randomized treadmill exercise tests: one while programmed for temperature-based, rate-modulated pacing and the other while programmed without rate modulation. In 1 pacemaker patient and 4 volunteers, heart rates were recorded during exposure to a hot water bath. Blood temperature measured at 10 sec intervals and pacing rate measured at 1 min intervals were telemetered to a diagnostic programmer and data collector for storage and transfer to a computer. Observation comments and ECG-derived heart rates were manually recorded. The temperature-based pacemaker was shown to respond promptly not only to physical exertion but also to emotionally caused stress and submersion in a hot bath. These events cause increased heart rate in the normal heart. Using a suitable algorithm to process the measurement of blood temperature, it was possible to produce appropriate pacing rates in paced patients.
Aged↗
Different responses of albumin-containing and alpha-fetoprotein-containing cells to estriol in the adult mouse liver.
A single intraperitoneal injection of 10 mg estriol (E3) rapidly induced a transient decrease in the serum albumin (ALB) level in 3 to 5 days in adult mice. At a dose of 5 mg, E3 showed a remarkable threshold effect on the decline of serum ALB. By immunohistochemistry, two types of ALB-positive cells were found in the liver. Type 1 cells were stained intensely and almost homogeneously throughout all or nearly all their entire cytoplasm, and type 2 cells showed only granular or vesicular cytoplasmic deposits. After administration of 10 mg E3, the type 1 cells diminished rapidly and markedly in direct proportion to the fall in serum ALB from the centro- and mediolobular zones, where they had been normally localized either singly or in small groups. Simultaneously, the granular or vesicular deposits that had been normally stained very weakly in the type 2 cells in the centro- and mediolobular zones became intensely stained along with cells in the perilobular zone. Alpha-fetoprotein (AFP)-containing cells in the liver appeared in maximal numbers at 5 to 7 days after E3 administration. These serological and cytological changes after E3 administration are here discussed on the basis of a possible inverse relationship between ALB and AFP gene expression.
Albumins↗
[Potentiation of inner ear damage following electron beam irradiation with CDDP administration].
The study was designed to examine the combined ototoxic effect of CDDP (Cisplatin, Cis-diammine dichloroplatinum) and electron beam irradiation, using guinea pigs. One group received physiological saline solution of 4 ml/kg/day, and another group received CDDP of 2 mg/kg/day for five days. And following the injection of saline or CDDP, the electron beam of 14Gy/day was applied to the both groups to the right ear for five days. Animals were sacrificed after 21 days, and temporal bones of these animals were removed for the inner ear histopathology. Temporal bones were classified into four groups (control, electron beam irradiation, CDDP administration, and combined administration group), and the inner ears were observed by the surface preparation technique with a phase contrast microscope, and by scanning and transmission electron microscopy, and by temporal bone study of serial sectioned slides. The main pathologic findings of the inner ear are as follows: Electron beam irradiation group showed no hair cell damage. CDDP group induced slight damage to the outer hair cells. Combined administration group (CDDP + electron beam irradiation) showed severe outer hair cell damage. Stria vascularis was degenerated moderately in the combined administration group and slightly in some animals of electron beam irradiation group. And Reissner's membrane and Hensen's cells, were damaged in the basal turn of cochlea of the combined administration group. All other cochlear structures (spiral ganglion, spiral lamina, basilar membrane, spiral prominence, tectorial membrane, blood vessels of the cochlea) and vestibular organs were lack of significant changes in all groups by a light microscopic observation. This study was clarified that combined administration of CDDP and electron beam irradiation showed severe ototoxic potentiation. Therefore, it is important that we must pay attention to the inner ear damage caused by combined therapy of CDDP and electron beam irradiation involving inner ear for the head and neck tumor.
Animals↗
[Clinical experience of a case applying temporal approach to zygomatic arch fracture].
The technique of temporal approach was originally introduced by Gillies (1927) for reduction of the zygomatic arch and zygomatic complex fracture. We reported a case of zygomatic arch fracture which was treated by temporal approach in a 36-year-old woman. She rode on a motorcycle and fell down on the ground, so she injured the right zygomatic region. Roentgenograms revealed right zygomatic arch and maxillary fracture. We performed a reconstructive operation for the right zygomatic arch fracture with temporal approach and fixated using an acrylic resin splint for 2 weeks. At 7 months after this operation, depression of the zygomatic region was improved and paralysis in the cheek and upper lip region gradually disappeared.
Adult↗
[Cells presenting GABA immunoreactivity in the hypothalamus of the cat].
The distribution of GABA-immunoreactive (IR) cells was studied by immunohistochemistry in conjunction with highly specific antiserum GABA in the cat hypothalamus. Colchicine pretreatment made it possible to visualize a large number of labeled cells in the medial preoptic and dorsal hypothalamic areas. In contrast, the ventromedial and anterior hypothalamic nuclei contained only a few labeled cells, and the paraventricular and supraoptic nuclei were devoid of them. A very dense network of GABA-IR presumptive terminals was seen in the ventrolateral posterior hypothalamus where labeled cells could be recognized. The possibility of an involvement of the GABAergic neuronal system in the regulation of sleep-waking cycle is discussed.
Animals↗
[Effect of RU 486 on glycogen metabolism in endometrium].
To elucidate the effect of the antiprogesterone steroid RU 486 (RU) on endometrial glycogen metabolism, a dose of 30 mg/kg of the agent was administered to pregnant rats on Day 2 (group 1) or Day 4 (group 2) of pregnancy, and glycogen content, glycogen synthetase (GS) and glycogen phosphorylase (GP) activities in the endometrium were investigated on Day 6. In addition, serum ovarian steroid hormones and the number of implantation sites were evaluated. The glycogen content in the endometrium in group 1 and group 2 decreased significantly (p less than 0.02 and p less than 0.05) compared with the control group. The total GS activity in the endometrium in group 1 decreased significantly (p less than 0.05). On the other hand, the independent GS activity in group 2 increased significantly (p less than 0.05) compared with the control group. The active GP activity in group 1 increased markedly, and the total GP activity increased significantly (p less than 0.05) compared with the control value. In group 2, the active and total GP activities increased significantly (p less than 0.01 and p less than 0.02) compared with the control values. Serum progesterone (P) concentrations in group 1 and group 2 were significantly (p less than 0.05 and p less than 0.05) lower than those in the control groups 2 days after the RU administration, and implantations were significantly (p less than 0.01 and p less than 0.01) inhibited. These results suggest that RU 486 affects endometrial glycogen metabolism, resulting in the prevention of implantation.
Animals↗
[A case of abdominal desmoid during pregnancy].
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Abdominal Muscles↗
[Role of progesterone in the ovulatory process of PMSG/hCG treated immature female rats].
To determine exactly when progesterone (P) acts as a most important mediator in the ovulatory process, a dose of 10mg/kg of RU486, an antiprogesterone, was administered to PMSG/hCG treated immature female rats (22 days old) at 0 (RU0 groups), 2 (RU2 group), 4,6,8 or 10 hours after an hCG injection, respectively. In the RU0 groups, the ovulatory effect of P was investigated at 0.2 (P2 group), 4 (P4 group), 6 or 8 hours after the hCG injection. Ovulation rates were calculated 24 hours after the hCG injections. Serum P and estradiol (E2) concentrations in the RU0 groups, the P2 group and the control rats (C group), were determined. The results were as follows. 1) The numbers of ova in the RU0, RU2 and RU4 group rats were significantly (p less than 0.01, p less than 0.01 and p less than 0.01) lower than that in the C group rats. 2) In the P2 and P4 groups, the numbers of ova were significantly (p less than 0.01 and p less than 0.01) increased compared with the RU0 group and returned to the control range. 3) In the RU0 group, the serum P and E2 concentrations within 8 hours after an hCG injection did not show any significant differences compared with the C group. In contrast, in the P2 group, the P concentrations at 4 and 6 hours after hCG increased significantly (p less than 0.01 and p less than 0.01) compared to the corresponding RU0 group. These results clarified an indispensable role of P in the ovulatory process within 6 hours after an hCG injection.
Animals↗
[Angiographic arterial embolization for control of intractable postpartum hemorrhage].
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Adult↗
[Prolactin receptor: characterization by monoclonal antibodies and cloning of complementary DNA].
Rat liver prolactin receptor has been partially characterized and purified to homogeneity using monoclonal antibodies. Pure receptor was digested with trypsin and amino acid sequence of receptor fragments determined. This allowed us to clone the prolactin receptor cDNA. Our approach to clone the receptor cDNA consisted of synthesizing oligonucleotides corresponding to the amino acid sequence of receptor fragments, and to screen a cDNA library. Sequencing reveals that prolactin receptor is a 291 amino acid protein, containing an extracellular domain of 210 residues, a single transmembrane segment of 24 amino acids and a cytoplasmic domain of 57 amino acids. Introduction of the prolactin receptor cDNA into various cell types demonstrates that the single protein is sufficient to bind prolactin with the same affinity and specificity reported for the prolactin receptor.
Animals↗
[BANA hydrolase and DNP peptidase activities in the ovulatory process of PMS-hCG treated immature rat].
To investigate the roles of collagenolytic enzymes in the ovulatory process of PMS-hCG treated immature female rats (22 days old), we measured the activities of two of them in the ovary by the using synthetic substrates alpha-N-benzoyl-DL-arginine-2-naphthylamide HCl (BANA) (a collagenolytic cathepsin) and dinitrophenol-Pro-Gln-Gly-Ile-Ala-Gly-Gln-D-Arg OH (DNP peptide) (a neutral collagenase). BANA hydrolase activities significantly began to increase after the hCG injection, reaching a peak 8-9 hours later, and then decreased sharply 10 hours later. There was also a significant increase in DNP peptidase activities 7-10 hours after the hCG injection and a significant decrease 12 hours after the injection. The present study has shown that BANA hydrolase and DNP peptidase appear during the ovulatory process of PMS-hCG-treated immature female rats, and that their significant preovulatory increases are contributory to collagenolysis in follicle rupture.
Animals↗