Biomedical subjects
Publications and source records attributed to T Yasui.
Transient involuntary movement of the leg developed during diagnostic or therapeutic angiography in five patients. The movement was jerky, brisk flexion/extension of the hip and knee joints on the side contralateral to acute ischemia. This movement may occur as a result of thromboembolic cerebral ischemia or as an ischemic complication of angiography.
A rare case of chronic subdural hematoma associated with a middle meningeal arteriovenous fistula was treated by a combination of embolization and burr hole drainage. This clinical situation might be missed in this era of computed tomography, when cerebral angiography is seldom indicated for the diagnosis of neuro-traumatic diseases. We should bear in mind the possibility of this clinical situation of a chronic subdural hematoma associated with a linear skull fracture crossing the middle meningeal groove in order to avoid possible hemorrhagic complications during surgery for chronic subdural hematoma.
OBJECTIVE: To clarify the mechanism of anovulation in hyperprolactinemic anovulatory women by subcutaneous (SC) pulsatile GnRH injection. DESIGN: Prospective clinical study. SETTING: Studies were made on at the Department of Obstetrics and Gynecology, the University of Tokushima, School of Medicine. PATIENTS: Six hyperprolactinemic (group 1) and 7 normoprolactinemic (group 2) anovulatory patients were studied. INTERVENTIONS: After examinations of pulsatile secretion of LH, the GnRH test, thyrotropin-releasing hormone test and estrogen test, pulsatile GnRH treatment (20 micrograms/2 hours SC) was performed. Two protocols were tested on each patient. In the non-hCG protocol, GnRH treatment was continued until ovulation. In the hCG protocol, 5,000 IU of hCG was injected to induce ovulation when follicles were fully mature. MAIN OUTCOME MEASURE: The rates of follicular maturation and ovulation, serum E2 and P in the two groups. RESULTS: Pulsatile LH secretion was impaired in both groups. LH release 48 hours after estrogen injection was impaired in group 1 but not in group 2. Follicles matured on pulsatile GnRH treatment in all cycles in both groups. However, with the non-hCG protocol, ovulation occurred in only 17% of group 1, but in 89% of group 2. With the hCG protocol ovulation occurred in all cycles in both groups. CONCLUSIONS: The main cause of anovulation is impaired gonadotropin pulsatility and derangement of the estrogen-positive feedback effect on LH secretion in hyperprolactinemic patients, their ovarian response to gonadotropin being well maintained. Subcutaneous pulsatile GnRH therapy combined with hCG can be used as an alternative to bromocriptine treatment for induction of ovulation in these patients.
Hydrostatic pressure-induced morphological and physiochemical changes in monomeric myosin were investigated. The turbidity of a myosin solution increased after release of pressure, indicating aggregation of the molecules. Some molecules were single headed after exposure to 100-200 MPa, in contrast with an intact molecule having two heads. Small-sized oligomeric species, composed of several molecules, appeared after pressurization at 200 MPa. The oligomers were formed only through head-to-head association. Neither head-to-tail nor tail-to-tail interaction was observed. With increasing pressure to 300 MPa, monomeric myosin remarkably decreased, and most molecules formed oligomers, in which the myosin heads were tightly associated, forming a clump, the tails of the myosin molecules extending radially from the clump. Such an oligomer was shaped like a daisy wheel and its morphology was quite similar to that formed on heating reported previously [Yamamoto et al. (1990) J. Biochem. 108, 896-898]. The aggregation of myosin molecules upon pressurization was concomitant with an increase in hydrophobicity, which was measured spectrofluorometrically with 8-anilino-1-naphthalene sulfonate, a probe for apolar binding sites. Although the turbidity increased continuously with increasing pressure, the hydrophobicity remained at a constant level above 200 MPa at pH 6.0 and above 300 MPa at pH 7.0. The loss of myosin ATPase activity was accompanied by aggregation of the molecules. These results indicate that hydrophobic groups in the heads of myosin are exposed to the surface of the molecule on pressurization, so that hydrophobic interaction among the heads occurs, yielding aggregates. Beside the hydrophobic interaction, the contribution of other interaction(s) is also suggested.
beta-Xylosidase of Aspergillus pulverulentus catalyzes a transxylosylation reaction from xylooligosaccharides to acceptor hydroquinone. Two transfer products were purified and their structures were examined. These were identified as hydroquinone beta-(1-->4)-xyloside and hydroquinone 4-O-(beta-xylosyl)-beta-xyloside. The hydrolysis of these glycosides apparently took place accompanying the synthesis of the transfer products.
A levoglucosan (1,6-anhydro-beta-D-glucopyranose)-using bacterium, isolated from soil, was identified. It was shown to belong to the genus Arthrobacter and tentatively named Arthrobacter sp. I-552. A novel enzyme catalyzed the dehydrogenation of levoglucosan to form 1,6-anhydro-beta-D-ribo-hexopyranos-3-ulose (3-keto levoglucosan), using NAD+ as an electron acceptor, i.e. NAD+: 1,6-anhydro-beta-D-glucopyranose oxidoreductase (trivial name: levoglucosan dehydrogenase). This enzyme was purified and characterized. A possible reaction scheme for the glucose formation was proposed. This pathway for levoglucosan use is distinct from those in yeast and fungi.
Five patients with kissing aneurysms (adherent internal carotid-posterior communicating artery and ipsilateral internal carotid-anterior choroidal artery aneurysms) are reported. There was female predominance and the subarachnoid hemorrhage was commonly due to rupture of the proximal posterior communicating artery aneurysm. Despite the demonstration of angiographic cleavage, the two aneurysms adhere to each other, which makes surgical dissection difficult. Meticulous dissection of the aneurysmal necks and preservation of the blood flow in the anterior choroidal artery are of vital importance.
Among the cases of ruptured aneurysms we have handled, some patients have rebled before surgery was performed. In this study, we examine the factors that contribute to the rerupture of cerebral aneurysms in the acute stage and suggest measures to prevent rerupture prior to surgery. We have encountered 32 cases of rebleeding prior to surgery. The rebleeding occurred within six hours of the initial subarachnoid hemorrhage (SAH) in 26 patients, among whom 21 rebled within three hours. Thirteen patients rebled during bed rest, 10 patients during angiography, 4 patients during CT scan and 5 patients in various other circumstances. Nine of the 10 patients who rebled during angiography had undergone the procedure within three hours of the initial SAH. Overall, the patients' condition deteriorated substantially after rebleeding. Considering these circumstances surrounding aneurysmal rerupture, we suggest the following measures for the prevention of preoperative rerupture in the acute stage: 1) maintenance of lowered blood pressure during the risky period; 2) intentional delay of performance of angiography until at least hours after the initial rupture, and 3) performance of surgery on an emergency basis.
Variations in the level of albumin mRNA and the transcription rate of the albumin gene in rats with adenine-induced renal failure were compared with those in normal rats. A paired feeding schedule was employed to eliminate any nutritional differences between normal rats and rats with adenine-induced renal failure. The albumin mRNA level isolated from the liver became lower as the period of adenine administration lengthened. However, there was no difference in the transcription rate of the albumin gene between the two rat groups. These results suggest that a post-transcriptional process is responsible for the renal failure-induced repression of albumin synthesis. Furthermore, plasma glucagon levels in adenine-induced renal failure specimens were markedly higher than those in the normal group, whereas we found no difference in the plasma insulin level between normal and adenine-fed rats. These investigations provide evidence that the decrease in the level of albumin mRNA in renal failure may be partly related to the elevated level of glucagon.
The authors report the surgical removal of four arteriovenous malformations (AVM's) in the brain stem causing hemorrhage. These included two intra-axial and two extra-axial AVM's. Three of the four were situated at the pons, and the remaining one in the posterior medullary velum. Complete surgical removal was obtained in the two extra-axial cases and in one of the intra-axial cases. The patient in whom complete removal was not obtained received partial embolization therapy with the remaining feeder being coagulated surgically. No patient was made permanently worse after surgery. One patient, in a comatose state on admission, died, while the remaining three patients showed useful recovery. These data indicate that surgical therapy with or without endovascular surgery appears to be possible for some AVM's and can be performed at an acceptable risk.
POU-domain transcription factors are known as developmental regulators which control organ development and cell phenotypes. In order to clarify the roles of POU-domain transcription factors in cell differentiation, we cloned a novel POU family gene, Epoc-1, from a murine thymus cDNA library. The amino acid (aa) sequence of the POU-specific domain of Epoc-1 is almost identical to those of Oct-1 and Oct-2. However, within the POU-homeodomain, 13 out of 60 aa differ between Epoc-1 and Oct-2. Recombinant Epoc-1 products were found to bind specifically to the octamer sequence. Epoc-1 was found to be expressed in skin, thymus, stomach and testis. In situ hybridization experiments and RNase protection assays indicated that Epoc-1 is expressed in the epidermal basal cells of the skin, which contain stem cells unipotent for keratinocyte differentiation and in thymic stromal elements. These results suggest that Epoc-1 might be one of the developmental regulators which controls epidermal development and thymic organogenesis.
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To clarify the mechanism of FSH secretion from the pituitary induced by activin A, we studied the interaction between activin A and gonadal steroids in inducing FSH release from primary cultured female rat pituitary cells in serum-free medium. The basal release of FSH was stimulated by activin A, testosterone (T) and progesterone (P), and T and P also facilitated basal FSH release stimulated by activin A. The GnRH-stimulated FSH release was facilitated by activin A, P and 17 beta-estradiol (E2), but suppressed by T. The effect of activin A on GnRH-stimulated FSH release was facilitated by P, but not affected by T or E2. These findings suggested that the interaction between activin A and T or P may be involved in the regulation of FSH secretion during the estrus cycle in rats.
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Effects of hyaluronan (HA) on the prostaglandin E2 (PGE2) production induced by recombinant human interleukin-1 beta (rhIL-1 beta) in rabbit articular chondrocytes were studied in vitro. The rhIL-1 beta-induced PGE2 production was dose-dependently inhibited by HA. HA with the highest molecular weight (M(r) = 2.0 x 10(6)) exhibited an inhibitory effect that was statistically more significant than the same polymer of lower molecular weights (M(r) = 1.0 x 10(6), 0.5 x 10(6)). This effect was observed in both young and adult rabbit articular chondrocytes. Since PGE2 has been implicated as a mediator of inflammatory joint diseases, our observations suggest that HA may elicit an anti-inflammatory effect by inhibiting PGE2 production.
A case is reported of a thrombosed giant aneurysm of the intracavernous carotid artery. Transient neurological deterioration was attributable to the acute swelling of the aneurysmal mass after rapid and massive intraluminal thrombosis. Characteristics on the magnetic resonance imaging of this case are reported and discussed.
We investigated the feasibility of specifically delivering adriamycin (ADR) to the regional lymph nodes via gastric submucosal injection of liposomal adriamycin (Lipo-ADR) in a rabbit model. We determined the tissue distribution of ADR for up to 7 days after the gastric submucosal injection of Lipo-ADR (0.4 mg/kg of ADR potency) and i.v. administration of an equal dose of free adriamycin (F-ADR). The area under the ADR concentration-time curve (AUC) of the regional lymph nodes was 85.4 micrograms.day/g after gastric submucosal injection of Lipo-ADR and 8.44 micrograms.day/g after i.v. administration of F-ADR. The targeting index of the regional lymph nodes, defined as the ratio of the AUC after gastric submucosal injection of Lipo-ADR to the AUC after i.v. administration of F-ADR, was 10.1. Gastric submucosal injection of Lipo-ADR enhanced lymph node-specific delivery of ADR compared with i.v. administration of F-ADR. The targeting index was 0.47 for the heart, 0.25 for the bone marrow, and 0.41 for the spleen, indicating that gastric submucosal injection of Lipo-ADR reduced delivery of ADR to these organs, as compared with i.v. administration of F-ADR. These data demonstrate that gastric submucosal injection of Lipo-ADR is well suited for specific delivery of ADR to the regional lymph nodes, suggesting that this method of administration may be useful in delivering preoperative adjuvant chemotherapy for preventing gastric cancer recurrence.
Effects of hyaluronic acid on the release of elastase from rat peritoneal leucocytes were studied by measuring the leucocyte elastase activity using a synthetic peptide substrate. Leucocyte elastase release was induced by opsonized zymosan, 12-O-tetradecanoyl phorbol-13-acetate (TPA) and N-formyl-L-methionyl-L-leucyl-L-phenylalanine combined with cytochalasin B. Calcium ionophore A23187 potentiated the action of TPA on leucocyte elastase release, whereas hyaluronic acid inhibited leucocyte elastase release regardless of the method of stimulation. Inhibitory effects of hyaluronic acid were dependent on its concentration and molecular weight. Hyaluronic acid of the highest molecular weight (2.0 x 10(6)) indicated a potent inhibitory effect on elastase release. Our present findings suggest that hyaluronic acid may elicit an anti-inflammatory effect by inhibiting leucocyte elastase-dependent pathological processes.