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Biomedical subjects

A Sakamoto

Publications and source records attributed to A Sakamoto.

At least 145 records · Page 8Linked to original sources
PubMed1997

The behavior of endometrial hyperplasia: a prospective study. Endometrial Hyperplasia Study Group.

OBJECTIVE: To clarify the behavior of endometrial hyperplasia in a prospective study. METHOD: Fifty-one patients with endometrial hyperplasia were followed up for 6 months. Samples of endometrial tissues were taken by uterine endometrial biopsy every 4 weeks during the first 3 months and at the end of follow-up. RESULTS: In 69% (35/51) of the patients histological picture of the endometrium became normal during the observation period. The lesions persisted in 17% (6/35) of the patients with simple hyperplasia, in 25% (1/4) of those with complex hyperplasia, in 14% (1/7) of those with simple atypical hyperplasia, and in 80% (4/5) of the patients with complex atypical hyperplasia. In the remaining 3 patients with simple hyperplasia, the lesions progressed to complex atypical hyperplasia by the end of follow-up, after showing a normal endometrium. CONCLUSION: Most cases of endometrial hyperplasia, except for complex atypical hyperplasia, disappeared spontaneously within a short period of time.

Adult↗
PubMed1997

Alteration in water channel AQP-2 by removal of AVP stimulation in collecting duct cells of dehydrated rats.

Dehydration increased the expression of aquaporin of collecting duct (AQP-2) and translocated AQP-2 to the apical plasma membranes from cytoplasmic vesicles of collecting duct cells. We determined whether the abrupt decrease in circulating arginine vasopressin (AVP) by giving excess water affects the expression of AQP-2 mRNA and subcellular localization of AQP-2 in collecting duct cells of the dehydrated rats. The 72-h water deprivation increased plasma AVP levels to 3.1 pg/ml and the expression of AQP-2 mRNA by 336% in rats, which were concomitantly abolished by the 40 ml/kg oral water load. A 50% inhibition ofAQP-2 mRNA expression was obtained with 20 min after the forced water load. In immunohistochemistry and electron microscopy, the AQP-2 was manifestly present around the apical edge of collecting duct cells in the 72-h dehydrated rats. The AQP-2 was diffusely translocated into the cytoplasm 1 h after the forced water administration. These results indicate that AVP plays the on-off regulation of AQP-2 mRNA expression and that a majority of AQP-2 is regulated by the shuttle recycling in the collecting duct cells.

Animals↗
PubMed1997

Bupivacaine combined with isoflurane synergistically depressed myocardial contractility in rat working heart preparation.

It is well known that both local and volatile anesthetics depress myocardial functions. This study was performed to evaluate the combined effects of commonly utilized local anesthetics (bupivacaine, mepivacaine, and lidocaine) and a volatile anesthetic (isoflurane) on heart rate and myocardial contractility in an isolated rat working heart preparation using each local anesthetic at 0 to 3 x 10(-4) (mol/L) with or without 1 MAC (minimum alveolar concentration) of isoflurane. The three local anesthetics depressed the heart rate and myocardial contractility dose-dependent. Bupivacaine depressed the heart rate more than the other two local anesthetics. One MAC isoflurane showed significant negative inotropic effects, and accelerated the effects of the local anesthetics. By using isobolographic analysis, we concluded that the combined effect of isoflurane and bupivacaine on myocardial negative inotropism was synergistic, while the effects of isoflurane and mepivacaine or lidocaine were additive.

Anesthetics, Inhalation↗
PubMed1997

External high-frequency oscillation for hypercapnia after upper abdominal surgery.

The purpose of this study was to evaluate the efficacy of external high-frequency oscillation (EHFO) in patients with hypercapnia following upper abdominal surgery. Seven patients were ventilated with EHFO for 2 hr at 60 oscillations/min, with cuirass pressures of 36 cm H2O (-26 to +10), and an inspiratory to expiratory ratio of 1:1. Blood gases and cardiac functional parameters were examined during the 2 hr on EHFO. Pulmonary functional parameters were analyzed prior to the institution and after the termination of EHFO. PaCO2 significantly decreased from 61 +/- 8 mmHg to 48 +/- 7 mmHg after 10 min on EHFO (p < 0.01). PaO2 significantly increased from 74 +/- 10 mmHg 95 +/- 26 mmHg after 1 hr on EHFO (p < 0.01). The heart rate decreased significantly from 108 +/- 27 beats/min to 101 +/- 24 beats/min after 30 min on EHFO (p < 0.05). The FEV1 and FVC significantly increased from 1.09 +/- 0.54 L to 1.50 +/- 0.46 L (p < 0.01) and from 1.90 +/- 0.74 L to 2.18 +/- 0.60 L (p < 0.05), respectively. The other parameters of lung function also significantly improved after the termination of EHFO. The significant changes in all of the pulmonary functional parameters continued for 1 hr after the termination of EHFO. EHFO is an effective method of gas exchange which is associated with earlier return to preoperative lung function.

Aged↗
PubMed1997

[The effects of subliminal and supraliminal presentation of trait-related words on person perception].

The present experiment was conducted to investigate how prior information affects subsequent person perception and when perceivers can control such an effect. One of three types of trait related words (i.e., hostility-related, friendliness-related, and neutral words) was subliminally or supraliminally presented to subjects, and subsequently, subjects rated the impression of four targets: a hostile person, a friendly person, a neutral person and themselves. Although results did not show that supraliminally presented words affected targets' impressions, they showed that the impressions sometimes varied with the valence of subliminally presented words regardless of targets' valence. The mechanism and controllability of priming effects in person perception were discussed.

Adult↗
PubMed1997

Evidence for monoclonal expansion of epithelial cells in ovarian endometrial cysts.

Ovarian endometrial cysts, one of the typical manifestations of endometriosis, are generated by the retention of cyclic hemorrhages and are classified as tumor-like lesions rather than neoplasms. Clonality analysis provides important information about the histogenesis and progression of neoplastic diseases. As it is generally accepted that most neoplasms are monoclonal in origin, however, the clonality of endometrial cysts remains uncertain. Using the human androgen receptor gene (HUMARA) as an X-linked polymorphic marker, we examined the clonal status of epithelial cells in endometrial cysts. We separated 21 fresh epithelial cell samples from 11 endometrial cysts and found that all were monoclonal in the methylation pattern of the HUMARA alleles. Moreover, in each of the five cysts from which epithelial cells were sampled from multiple and distant areas, the methylation patterns of all samples from a single cyst were identical. These data indicate that endometrial cysts are monoclonal in origin and suggest their neoplastic potentiality.

Adult↗
PubMed1997

[Study on Mato cells (Mato's FGP cells) under various conditions].

Mato cells are unique macrophagic cells locating in the Virchow-Robin space of cerebral microvessels. They play a significant role in blood brain barrier, and uptake and digest proteinous and lipoidal materials derived from surroundings. They are provided with epitopes of macrophage lineages such as MHC Class II and scavenger receptor. Under pathological conditions, -cerebral injury, hypercholesteremia, hypertension and congenital dysfunction of nerve and some enzymes-induce heavy damages of Mato cells in shape and contents, and some of Mato cells are going into degeneration. Subsequently, the architecture of microvessels is also modified and result in the narrowing of vascular luminae. Finally, the authors discusses these findings referring to the earlier reports of Alzheimer (1913).

Aging↗
PubMed1997

[Assessment of quality of life in long-term results of patients over 75 years old after emergent cardiovascular surgery].

Long-term results in QOL of patients over 75 years old after emergent cardiovascular surgery were examined. From January 1991 to June 1996, 46 patients underwent cardiovascular surgery. 22 patients who had elective surgery (elective group) and 15 patients who had emergency surgery (emergency group) tolerated with the operation: Two-year survival rate after surgery was 80.7% in the elective group and 78% in the emergency group, and relative survival rate was 0.89 in the elective group and 0.86 in the emergency group. As regards to the ability to live independently, 89% of elective group and 75% of emergency group showed good improvement, and there was no significant difference between two groups. The rate of patients who did not feel anxiety for disease at all was 61.1% in the elective group and 41.7% in the emergency group. The relationship between the patient and his family was good in both groups. For physical condition, the emergency group was superior to the elective group with no significant difference. Although QOL was relatively good after emergency surgery, some items were inferior compared with elective surgery. To improve the long-term results, elective surgery is required to avoid emergency surgery.

Age Factors↗
PubMed1997

[Surgery for acute aortic dissection extending to the aortic root using gelatine-resorcine-formol biological glue--a case report].

A 73-year-old woman was admitted with chest pain of sudden onset and hypotension. Enhanced CT showed the dilated ascending aorta with an intimal flap. Emergency surgery was performed under a diagnosis of type A acute aortic dissection and cardiac tamponade. Replacement of the ascending aorta was planned, but during the operation we found that the dissection had extended to the aortic root and that the laceration of the adventitia was located just distal to the aortic annulus. Since the laceration was closer to the aortic annulus than the coronary ostium, it was impossible to reconstruct the aortic stump by classical techniques using Teflon felt strips. Gelatine-Resorcine-Formol (GRF) glue was therefore used to reinforce the proximal aortic stump. We then curved the suture line of the proximal anastomosis so as to resect the laceration while preserving the ostia of the coronary arteries. We were thus able to perform simple replacement of the ascending aorta successfully and the postoperative course was uneventful. By using GRF glue, replacement of the aortic root can be avoided in such cases.

Acute Disease↗
PubMed1997

The postoperative drain-clamping method for hemostasis in total knee arthroplasty. Reducing postoperative bleeding in total knee arthroplasty.

We attempted to decrease the amount of postoperative bleeding after total knee arthroplasty (TKA) by clamping the suction drain and through retrograde infusion of saline containing a low concentration of epinephrine. When TKA was completed and the sutured wound was bandaged, 50 ml of saline containing epinephrine diluted to 1:200,000 and 0.5 g of antibiotic was injected into the knee joint via the inserted suction drain. The drain was clamped for 20 hours and then unclamped to begin aspiration until 48 hours after surgery. To clarify the effectiveness of this method, patients were divided into three groups. Group I consisted of 116 knees (in 95 patients) infused with 50 ml saline containing a low dose of epinephrine: Group II was composed of 70 knees (42 patients) infused with 50 ml saline only; and Group III included 97 knees (78 patients) who did not undergo this drain-clamp method. The average amount of postoperative bleeding was 207 ml in Group I, 255 ml in Group II (p < 0.01), and 501 ml in Group III (p < 0.001). With this method of using saline with a low dose of epinephrine and sustained clamping of up to 20 hours, we have been able to operate on elderly patients with rheumatoid arthritis without blood transfusion, even in cases of simultaneous bilateral TKA. Drain-clamping with saline infusion effectively controlled postoperative bleeding after TKA, and when epinephrine was added to the saline, the hemostatic effect was even greater than that of saline alone.

Adult↗
PubMed1996

Memantine induces heat shock protein HSP70 in the posterior cingulate cortex, retrosplenial cortex and dentate gyrus of rat brain.

High-affinity N-methyl-D-aspartate (NMDA) receptor antagonists like MK-801 are known to induce the heat shock protein, HSP70, in the posterior cingulate cortex and retrosplenial cortex of rat brain. Memantine, which is a low affinity uncompetitive NMDA receptor antagonist, has been used in the treatment of Parkinson's disease in Europe. The faster kinetics of memantine in blocking and unblocking the NMDA receptor-operated ion channel as opposed to high-affinity NMDA antagonists like MK-801 has been thought to account for the safety of memantine. The present study evaluated the neurotoxic potential of memantine and amantadine using the induction of HSP70 immunoreactivity in rat brain. Memantine (25, 50, 75 mg/kg) induced HSP70 in the posterior cingulate, retrosplenial cortex and dentate gyrus of rat brain. In contrast, amantadine (50, 100, 200 mg/kg) did not induce HSP70 in the rat brain. These results suggest that memantine has an antagonistic effect at NMDA receptor in vivo, and raises the possibility that high doses of memantine may cause neuronal damage similar to those observed with other high-affinity NMDA receptor antagonists.

Animals↗
PubMed1996

Effects of insulin and transferrin on the generation of lymphokine-activated killer cells in serum-free medium.

We have developed a serum-free medium designated RDSF for the generation of LAK cells based on RD6F medium, which was originally developed as a serum-free medium for the growth of myeloma and hybridoma cells. The cytotoxic activity of LAK cells generated in RDSF against Raji, K562 and oral cancer cells, is 3-4 times that of LAK cells generated in medium containing 10% human type AB serum. RDSF medium consisted of nutrient mixture supplemented with transferrin, 2-aminoethanol, 2-mercaptoethanol, sodium selenite and interleukin-2. In this study, we have found that insulin which has been shown to be the most important polypeptide hormone in serum-free media for animal cells, inhibited the generation of cytotoxic activity of LAK cells cultured from peripheral blood lymphocytes. In addition, we found that transferrin was an essential component for the growth and generation of LAK cells in serum-free culture. These results suggest that RDSF may be useful in adoptive immunotherapy for cancer as well as for studying factors involved in the growth and differentiation of LAK cells.

Cell Culture Techniques↗
PubMed1996

Involvement of specific macrophage-lineage cells surrounding arterioles in barrier and scavenger function in brain cortex.

The transport of solutes between blood and brain is regulated by a specific barrier. Capillary endothelial cells of brain are known to mediate barrier function and facilitate transport. Here we report that specific cells surrounding arterioles, known as Mato's fluorescent granular perithelial (FGP) cells or perivascular microglial cells, contribute to the barrier function. Immunohistochemical and in situ hybridization studies indicate that, in normal brain cortex, type I and type II macrophage scavenger receptors are expressed only in FGP/perivascular microglial cells, and surface markers of macrophage lineage are also detected on them. These cells mediate the uptake of macromolecules, including modified low density lipoprotein, horseradish peroxidase, and ferritin injected either into the blood or into the cerebral ventricles. Accumulation of scavenged materials with aging or after the administration of a high-fat diet results in the formation of honeycomb-like foam cells and the narrowing of the lumen of arterioles in the brain cortex. These results indicate involvement of FGP/perivascular microglial cells in the barrier and scavenger functions in the central nervous system.

Adult↗
PubMed1996

Contribution of sustained Ca2+ elevation for nitric oxide production in endothelial cells and subsequent modulation of Ca2+ transient in vascular smooth muscle cells in coculture.

To elucidate the intracellular Ca2+ (Ca2+i ) transient responsible for nitric oxide (NO) production in endothelial cells (ECs) and the subsequent Ca2+i reduction in vascular smooth muscle cells (VSMCs), we administrated four agonists with different Ca2+i-mobilizing mechanisms for both cells in iso- or coculture. We monitored the Ca2+i of both cells by two-dimensional fura-2 imaging, simultaneously measuring NO production as NO2-. The order of potency of the agonists in terms of the peak Ca2+i in ECs was bradykinin (100 nM) > ATP (10 microM) > ionomycin (50 nM) > thapsigargin (1 microM). In contrast, the order in reference to both the extent of Ca2+i reduction in cocultured VSMCs and the elevation in NO production over the level of basal release in ECs completely matched and was ranked as thapsigargin > ionomycin > ATP > bradykinin. Treatment by NG-monomethyl-L-arginine monoacetate but not indomethacin or glybenclamide restored the Ca2+i response in cocultured VSMCs to the isoculture level. In ECs, when the Ca2+ influx was blocked by Ni2+ or by chelating extracellular Ca2+, all four agonists markedly decreased NO production, the half decay time of the Ca2+i degenerating phase, and the area under the Ca2+i curve. The amount of produced NO hyperbolically correlated to the half decay time and the area under the Ca2+i curve but not to the Ca2+i peak level. Thus, the sustained elevation of Ca2+i in ECs, mainly a result of Ca2+ influx, determines the active NO production and subsequent Ca2+i reduction in adjacent VSMCs. Furthermore, L-arginine but not D-arginine or L-lysine at high dose (5 mM) without agonist enhanced the NO production, weakly reduced the Ca2+i in ECs, and markedly decreased the Ca2+i in VSMCs, demonstrating the autocrine and paracrine effects of NO (Shin, W. S., Sasaki, T., Kato, M., Hara, K., Seko, A., Yang, W. D., Shimamoto, N., Sugimoto, T., and Toyo-oka, T. (1992) J. Biol. Chem. 267, 20377-20382).

Animals↗
PubMed1996

Inhibition of nitric oxide formation with L-canavanine attenuates endotoxin-induced vascular hyporeactivity in the rat.

L-Canavanine, a selective inhibitor of inducible nitric oxide (NO) synthase, has beneficial effects on the circulatory failure of rats with endotoxin shock. To investigate the direct relationship between these beneficial effects and the inhibition of the formation of NO in response to L-canavanine in endotoxin shock in the rat, we detected changes in venous nitrosyl-hemoglobin (NO-hemoglobin) levels using an electron spin resonance (ESR) assay. Anaesthetized rats were injected with lipopolysaccharide (10 mg/kg i.v.). 1 h after the lipopolysaccharide injection, the rats were divided into four groups: a lipopolysaccharide group receiving 0.3 ml of saline hourly, an L-canavanine 10 or an L-canavanine 20 group receiving L-canavanine 10 or 20 mg/kg i.v. hourly, respectively, and an L-NAME group receiving NG-nitro-L-arginine methyl ester (L-NAME) 15 mg/kg followed by 10 mg/kg i.v. hourly. A sham group received saline instead of lipopolysaccharide, and an L-canavanine group received L-canavanine 20 mg/kg i.v. hourly, 1 h after the saline injection. At 5 h after the lipopolysaccharide or saline injection, pressor responses to noradrenaline (1 microgram/kg i.v.) were obtained. In the lipopolysaccharide group, lipopolysaccharide caused a progressive decrease in mean arterial pressure and an impairment of pressor responsiveness to noradrenaline. Administration of L-canavanine or L-NAME attenuated the endotoxin-induced hypotension and vascular hyporeactivity to noradrenaline. L-Canavanine did not alter mean arterial pressure and the pressor response to noradrenaline in the L-canavanine group. The endotoxin-induced increases in venous levels of NO-hemoglobin were significantly inhibited by L-canavanine or L-NAME. These data indicate that the beneficial hemodynamic effects of L-canavanine are associated with inhibition of the enhanced formation of NO by inducible NO synthase in a rat model of endotoxin shock. L-Canavanine is a potential agent in the treatment of endotoxin shock.

Animals↗
PubMed1996

Optimal schedule for administering granulocyte colony-stimulating factor in chemotherapy-induced neutropenia in non-small-cell lung cancer.

A prospective randomized study was conducted to determine the optimal schedule of rhG-CSF (recombinant human granulocyte colony-stimulating factor). A group of 33 lung cancer patients treated with MVP therapy (mitomycin, vindesine, and cisplatin) were randomly assigned to three groups: an early prophylaxis group in which rhG-CSF was initiated on day 2 of the MVP cycle; a late prophylaxis group in which rhG-CSF was initiated on day 8; and a therapeutic group in which rhG-CFS was initiated after the onset of neutropenia. Ten patients who had received MVP therapy without rhG-CSF were also analyzed as a no-support group. The incidence of neutropenia was 80% (16/20 courses) in the early prophylaxis group, 44% (8/18) in the late prophylaxis group, 94% (17/18) in the therapeutic group, and 94% (16/17) in the no-support group. The incidence of neutropenia in the late prophylaxis group was less than in the early prophylaxis group (P<0.05), the therapeutic group (P<0.01), and the no-support group (P<0.01). The late prophylactic rhG-CSF schedule was therefore more effective in countering neutropenia than either the early prophylactic or therapeutic schedule.

Aged↗
PubMed1996

A zinc-finger-type transcription factor WZF-1 that binds to a novel cis-acting element of histone gene promoters represses its own promoter.

WZF-1 is a zinc-finger protein which binds to the wheat histone gene promoter. Southwestern-binding analyses revealed that it bound a CACTC sequence, a novel positive cis-acting element. The activity of WZF-1 gene promoter, containing six CACTC sequences, was markedly reduced when WZF-1 was co-expressed, suggesting that WZF-1 is a transcriptional repressor.

Base Sequence↗