Biomedical subjects

T Morimoto

Publications and source records attributed to T Morimoto.

At least 271 records · Page 15Linked to original sources

PubMed1996

Expanding laminoplasty for cervical myelopathy-spinous process roofing technique.

We have carried out expanding laminoplasty using spinous process roofing technique for patients presenting with cervical myelopathy. The technique is a modified Kurokawa's method. The result shows that laminoplasty with this technique provides better postoperative neck movement with a simpler surgical procedure. The clinical material consists of 54 cases with more than 3 years follow-up. Long-term investigation was performed focusing on the following three points, (1) bony fusion rates, (2) radiographic neck movement, (3) neurological improvement. The results indicate good postoperative bony fusion in all cases. Postoperative neck movement was also well preserved in the majority of cases.

Adult↗

PubMed1996

Correlation between spinal cord blood flow and arterial diameter following acute spinal cord injury in rats.

Simultaneous measurements of spinal cord blood flow and arterial diameter at areas adjacent to a site of spinal cord injury were carried out to determine changes in CO(2) reactivity and autoregulation. The spinal cord injury was made at T10 level by the epidural clip compression method. A spinal window was drilled at an area either 7 mm caudal or 7 mm rostral to the injury site for the measurement of spinal cord blood flow and arterial diameter at the same time. Spinal cord blood flow was decreased at both spinal windows, especially at the rostral window. Arterial diameter was also decreased significantly at both sites. The ischaemic zone evaluated histologically tended to expand more diffusely in the rostral direction than in the caudal direction. In the pre-injury stage, both CO(2) reactivity and autoregulation were present in the spinal cord. Following the clip injury, CO(2) reactivity and autoregulation were both impaired in the areas 7 mm adjacent to the impact site. Correlation coefficients suggested that the rostral spinal cord tended to sustain more injury than the caudal spinal cord. The histologically proven spinal cord ischaemia following the injury may have resulted from the decreased arterial diameter and impaired CO(2) reactivity and dysautoregulation of the spinal cord.

Animals↗

PubMed1996

Modulation of thermogenic response to parenteral amino acid infusion in surgical stress.

Thermogenic response to parenteral infusion of amino acid mixtures in rats undergoing surgical stress was investigated with the aid of a small animal indirect calorimeter. Male Wistar rats (n = 12) were laparotomized and received intestinal abrasion along with construction of a parenteral route. After 48 h, nutrient-induced thermogenesis (NIT) produced by amino acid mixtures was examined and compared with that of control rats (n = 12) without surgical stress. The NIT values of the leucine-enriched solution were greater than those of the control solution in both rats with and without surgical stress. The NIT generated by the leucine-enriched solution in rats with surgical stress was significantly higher than that in rats without. NIT values for 10 different kinds of single amino acid solutions with identical concentrations was then examined in 60 rats. The NIT values of the leucine and the glycine solutions were relatively higher than those of other solutions. However, when puromycin was injected intraperitoneally into 12 rats just before measurement of the NIT in response to amino acid mixtures, no significant differences were found in NIT values between the mixtures. In summary, surgical stress increased the thermogenic response to the leucine-enriched solution, indicating that utilization of leucine may be augmented under surgical stress. In fact, leucine itself may be a thermogenic amino acid. Inhibition of protein synthesis prevented the increase in thermogenic response induced by the leucine-enriched solution. We conclude that thermogenic responses to parenteral amino acid mixtures may differ depending not only upon the compositions of amino acids but also upon the host conditions.

Amino Acids↗

PubMed1996

Postoperative adjuvant randomised trial comparing chemoendocrine therapy, chemotherapy and immunotherapy for patients with stage II breast cancer: 5-year results from the Nishinihon Cooperative Study Group of Adjuvant Chemoendocrine Therapy for Breast Cancer (ACETBC) of Japan.

Between 1985 and 1988, the effect of using ftorafur (FT) or PSK (an immunotherapy agent) in combination with the conventional postoperative adjuvant therapy using mitomycin (MMC) plus tamoxifen (TAM) was assessed in stage II, oestrogen receptor-positive (ER+) breast cancer patients. Furthermore, in ER- breast cancer stage II patients, the effects of postoperative adjuvant therapy using MMC plus FT were compared with the effects of postoperative adjuvant therapy using MMC plus PSK. Patients had primary stage II breast cancer and had undergone total mastectomy plus axillary dissection or more radical surgery. On the day of surgery, MMC (13 mg/m2) was administered intravenously. Then, ER+ patients received one of three regimens of drug therapy, starting 2 weeks after surgery: regimen A (daily oral treatment with 30 mg of TAM), regimen B (daily oral treatment with 30 mg of TAM and 600 mg of FT) or regimen C (daily oral treatment with 30 mg of TAM and 3 g of PSK) [corrected]. ER- patients received either regimen D (daily oral treatment with 600 mg of FT) or regimen E (daily oral treatment with 3 g of PSK), starting 2 weeks after surgery. Of the 540 ER+ patients registered, 525 were evaluated. The 5-year overall survival rate for ER+ patients was higher for patients who received regimen B (94.2%) than for those who received regimen A (86.9%) or regimen C (89.9%) (P = 0.063). The 5-year relapse-free survival rate was higher for regimen B (88.9%) than for regimen A (78.6%) and regimen C (77.2%) (P = 0.010). Stratified analysis revealed better results with the FT-combined therapy in patients positive for lymph node metastasis and premenopausal patients. These results indicate the effectiveness of using FT in combination with TAM. Of the 376 ER- patients registered, 364 were evaluated. The 5-year overall and relapse-free survival rate for ER- patients did not differ significantly between patients who received regimen D and those who received regimen E.

Adult↗

PubMed1996

Ischemic preconditioning of the liver in rats: implications of heat shock protein induction to increase tolerance of ischemia-reperfusion injury.

It has been reported that ischemic preconditioning of the heart or brain has a possible relevance to heat shock protein (HSP). It is still unknown, however, whether HSP induced by means of ischemic preconditioning of the liver is a direct factor in the acquisition of tolerance to succeeding ischemia-reperfusion injury. In the present study we used ischemic preconditioning of the liver to verify the effects of induced HSP72 in the liver on the subsequent longer warm ischemia and reperfusion. Rats preconditioned with short-term (15-minute) ischemia were compared with rats preconditioned by heat exposure or with control rats. After a 48-hour recovery from the sublethal stress for preconditioning, all rats were exposed to longer (30-minute) warm ischemia and reperfusion. Forty-eight hours after ischemic preconditioning, HSP72 was clearly induced in the liver, as well as in the liver preconditioned with heat shock, but not in the kidney or heart. This ischemic preconditioning also attenuated the liver damage in the subsequent ischemia-reperfusion injury, improving the restoration of hepatic function during reperfusion and resulting in higher postischemic rat survival. According to the proposed model of tolerance acquisition for ischemia-reperfusion injury by stress preconditioning, these observations support the speculation that the induced HSP72 plays some beneficial role in this protection mechanism.

Adaptation, Physiological↗

PubMed1996

Simultaneous measurement of salicylate hydroxylation and glutamate release in the penumbral cortex following transient middle cerebral artery occlusion in rats.

Using the microdialysis technique and laser-Doppler flowmetry, we performed simultaneous measurement of salicylate hydroxylation and glutamate release along with local CBF in the ischemic penumbral cortex of rat brain subjected to normothermic transient middle cerebral artery (MCA) occlusion. Cortical CBF fell to 24 +/- 11% (mean +/- SD) during ischemia and recovered to 84 +/- 16% during reperfusion. Extracellular glutamate levels increased by 6.5-fold above baseline 10 min following MCA occlusion but subsequently returned to near baseline levels in spite of the persistent ischemia. Increase in 2,3- and 2,5-dihydroxybenzoic acid (DHBA) concentrations in the microdialysis perfusate was confirmed during both ischemia and reperfusion phase. Although the temporal profile and amount of salicylate hydroxylation were heterogeneous among individual animals, integrated 2,3-DHBA concentrations during reperfusion were correlated positively with integrated glutamate concentrations during ischemia and negatively with mean postischemic CBF. These relationships suggest a possible association of the enhanced production of 2,3-DHBA during reperfusion with larger amounts of intraischemic glutamate release and lower levels of post-ischemic CBF.

Acid-Base Imbalance↗

PubMed1996

Comfortable zone of the mandible evaluated by the constant stimuli method.

For evaluation of the comfortable zone (CZ) and the most comfortable position (MCP) of the occlusal vertical relation of the mandible, the constant stimuli method with three subjective categories of judgements was applied in 10 edentulous subjects. The evaluated CZ was stable and about 3 mm in width. The occlusal vertical dimension (OVD) of the existing dentures was found to be located within the CZ in nine of the 10 subjects.

Aged↗

PubMed1996

Alteration in the bite force and EMG activity with changes in the vertical dimension of edentulous subjects.

The bite force and EMG activity of jaw closing muscles were studied at seven different vertical jaw positions around the occlusal vertical dimension (OVD) in 10 edentulous subjects. When the masseteric EMG activity was maintained at constant values (40% and 20% of the maximum activity at the OVD), the bite force increased in proportion to increase of the vertical dimension. On the other hand, when the bite force was maintained at constant values (4 kg and 8 kg), the EMG activities of the jaw closing muscles decreased, with an increase of the vertical dimension. These results indicate that the OVD is not the position at which the most efficient exertion of the bite force is obtained.

Adaptation, Physiological↗

PubMed1996

Diffusivity of oxygen in microvascular beds as determined from PO2 distribution maps.

Dynamic changes in the distribution of PO2 in the rat mesentery were measured to determine the O2 diffusion coefficient (DO2) and consumption rate (VO2). The distribution of PO2 was obtained in two-dimensional maps by microscopic fluorometry on the basis of oxygen quenching. The corresponding vasculature was also recorded on a video recorder to analyze the PO2 distribution consistent with the arrangement of the microvessels. Anesthetized rats breathing room air were subjected to 100% O2 ventilation to induce dynamic changes in PO2 distribution. We assumed a homogenous and constant VO2 in the tissue, and a one-dimensional diffusion equation was applied to simulate oxygen transport. The PO2 data corresponded very well to the theoretical curves, and calculated DO2 was 1.04 +/- 0.78 X 10(-5) cm2/s (mean +/- SD, n = 38) and VO2 was 8.2 +/- 3.9 x 10(-6) cm3 O2.cm-3 tissue.s-1 (n = 27) at 37 degrees C. However, PO2 values at points remote from the arterioles remained higher than the theoretical prediction.

Animals↗

PubMed1996

Evaluation of the protective effect of a novel prostacyclin analog on mesenteric circulation following warm ischemia.

The protective effect of a novel prostacyclin (PGI2) analog, OP-2507, on mesenteric circulation was investigated in a canine warm ischemia model. In 20 mongrel dogs, the entire portion of the intestine supplied by the superior mesenteric artery (SMA) and drained by the superior mesenteric vein (SMV) was completely isolated, maintaining the blood and lymph vessels intact. Sixty or 120 min of complete warm ischemia (WI) of the intestine was induced by clamping SMA and SMV, followed by reperfusion for 120 min. Animals were divided into five groups (each n = 4): group 1, sham operation; group 2, 60 min WI; group 3, 120 min WI; group 4, 60 min WI with PGI2 analog administration; group 5, 120 min WI with PGI2 analog administration. The analog was administered at a rate of 6 micrograms.kg-1.h-1 immediately after laparotomy until the end of the observation period. Mean arterial pressure, SMA blood flow (SMABF), SMV pressure were monitored and total mesenteric vascular resistance (TMVR) was calculated. To evaluate the endothelial activation, endothelin, which is secreted from the endothelium under hypoxic stress, was assayed from blood samples of SMV. None of the animals showed significant changes in mean arterial pressure. In groups 2 and 3, SMABF decreased significantly to less than 60% of preoperative value (15 ml.kg-1.min-1) and TMVR significantly increased from 8.1 and 7.3 mm Hg.ml-1.kg.min before WI to 14.0 and 16.4 mm Hg.ml-1.kg.min after 120 min reperfusion, respectively, resulting in delayed hypoperfusion. In contrast, in groups 4 and 5, SMABF increased to over 100% of preoperative level, while TMVR declined from 7.8 and 8.4 mm Hg.ml-1.kg.min before WI to 6.2 and 6.3 mm Hg.ml-1.kg.min after 120 min reperfusion. After 60 min reperfusion, SMABF and TMVR showed a significant difference between the treated and nontreated groups. Only in group 3, high endothelin concentrations (over 20 pg/ml) were observed even after 120 min reperfusion. It was concluded that the PGI2 analog was able to suppress the endothelial activation and the disturbance of mesenteric circulation caused by WI and reperfusion.

Animals↗

PubMed1996

Tongue, jaw, and lip muscle activity and jaw movement during experimental chewing efforts in man.

The electromyographic (EMG) activity of the human genioglossus (GG) muscle during chewing efforts is not fully understood. In this study, the EMG activity of the human GG muscle during unilateral gum chewing was illustrated and correlated with the activities in the anterior temporalis (AT), the anterior digastric (DG), and the inferior orbicularis oris (OI) muscles. GG muscle activity was measured with customized surface electrodes, while other muscles were recorded with conventional surface electrodes. EMG activities during tongue displacement and the articulation of long vowels, recorded by the customized electrodes, were consistent with the recordings obtained by fine wire electrodes placed in the GG muscle. Jaw displacement was monitored by means of a kinesiograph with a transducer attached to the mandibular central incisors. Mean normalized GG muscle activity showed an onset in the last one-fifth of the intercuspal phase, gradually increasing during jaw-opening, and at its greatest immediately before the maximum jaw-opening position. It then decreased during jaw-closing and ceased in intercuspation but showed a small rebound in the third fifth of the intercuspal phase. The GG muscle burst showed phase lags with the DG and OI muscles and an opposite phase with the AT muscle (all P < 0.0001). All correlations were statistically significant (all P < 0.0001, r values between 0.88 and 0.97). The results suggest central coordination of the timing of the activities of the jaw, lip, and tongue muscles in chewing.

Adolescent↗

PubMed1996

ATP is required in platelet serotonin exocytosis for protein phosphorylation and priming of secretory vesicles docked on the plasma membrane.

Calcium-evoked secretion generally requires the presence of millimolar concentrations of Mg-ATP. We investigated the role of Mg-ATP in the secretion of serotonin from electropermeabilized bovine platelets. The secretion of serotonin was lost within 5 minutes when the Mg-ATP concentration was diluted to less than 0.1 mM, but was maintained when ATP-gamma S (adenosine 5'-O-3-thiotriphosphate) was used instead of ATP. Okadaic acid, a potent inhibitor of protein phosphatase, could also maintain the exocytotic activity even when ATP was diluted. Decrease in the secretory activity was paralleled by a decrease in phosphorylation level of four proteins after dilution of ATP, but the activity was maintained when the thiophosphorylation level of these proteins was maintained. Two of these proteins were digested by a protease, calpain, which has been shown to lead to a loss in the exocytotic activity. Electron microscopic studies showed that calcium did not induce the formation of distinct bridge-like structures between the granule membrane and the plasma membrane in Mg-ATP-diluted cells, previously shown as the structure transiently formed prior to fusion of the two membranes. Anchorage of the secretory dense granules to the plasma membrane and the presence of the amorphous structures between the granules and the plasma membrane were unchanged by dilution of ATP. These results indicate that ATP is not required for the anchorage itself, but is required to prime anchored granules for calcium-triggered secretion. Maintenance of the phosphorylated state of proteins by ATP enables the calcium trigger to form the bridge-like structures preceding membrane fusion events.

Adenosine Triphosphate↗

PubMed1996

Antitumor-promoting activities of various synthetic 1-O-acyl-3-O-(6'-O-acyl-beta-D-galactopyranosyl)-sn-glycerols related to natural product from freshwater cyanobacterium Anabaena flos-aquae f. flos-aquae.

1-O-Acyl-3-O-(6'-O-acyl-beta-D-galactopyranosyl)-sn-glycerol, which was isolated from a nitrogen-fixing fresh water cyanobacterium, Anabaena flos-aquae f. flos-aquae, was synthesized by utilizing lipase-catalyzed acylation. The antitumor-promoting activities of these galactolipids were evaluated using a short-term in vitro assay of Epstein-Barr virus activation in Raji cells induced by 12-O-tetradecanoyl- phorbol 13-acetate (TPA). The glyceroglycolipids which have a palmitoleoyl residue at the 1-O-position exhibited more potent activities than the others in this assay.

Anabaena↗

PubMed1996

Transplantation of the cadaver heart harvested one hour after hypoxic cardiac arrest using the core-cooling technique in dogs.

A shortage of donor organs in clinical transplantation prompted us to study whether resuscitated dead hearts could be utilized for successful orthotopic heart transplantation. After 60 min of hypoxic cardiac arrest, one group of canine hearts was resuscitated (Res group, n = 6). The other group was harvested directly (Non-Res group, n = 6). In the Res group, cardiopulmonary bypass was utilized for resuscitation at 37 degrees C and the animals were then core-cooled to 15 degrees C. The hearts then were preserved in University of Wisconsin solution and orthotopically transplanted. Stable prostacyclin analogue (OP2507) and verapamil, a calcium antagonist, were added to the cardioplegia, and substrate-enriched warm blood cardioplegia and a hydroxy radical scavenger (EPC) were administered at the time of reperfusion of the transplanted heart. All animals in each group were successfully weaned from cardiopulmonary bypass with dopamine (5 micrograms/kg/min). Cardiac function without dopamine was better preserved in the Res group than the Non-Res group (Emax: 130.6 +/- 41.5% vs. 47.1 +/- 24.7%; mean +/- SD, as percent of postbrain death values, P < 0.01 by unpaired t-test). Cadaver hearts 60 min after anoxic arrest can be successfully re-animated and orthotopically engrafted. In addition, the core-cooling technique is useful. We believe this study serves as the key step in the clinical application of dead hearts to successful cardiac transplantation.

Animals↗

PubMed1996

A study of monoamine oxidase activity in fetal membranes.

OBJECTIVE: To study the role of decidual monoamine oxidase (MAO)-A and -B activities before delivery, the relationship between MAO activity in fetal membranes and catecholamine (CA) concentration in amniotic fluid (AF) was determined. METHODS: Fetal membranes and AF were obtained at the time of elective Cesarean section (CS group, n = 11) and Cesarean section due to fetal distress without labor pains (FD group, n = 5). MAO-A and -B activities were radiometrically measured using 14C-5-hydroxytriptamine for MAO-A substrate and 14C-benzylamine for MAO-B substrate. CA concentrations in AF were measured by high performance liquid chromatograph with an electro-chemical detector. RESULTS: Both MAO-A and -B activities in decidua obtained from CS were significantly lower than those obtained from FD. Both norepinephrine (NE) and epinephrine (EP) concentrations were significantly lower in the CS group than the FD group. A significant positive correlation between decidual MAO-A activity and NE concentration in AF was observed. No significant correlation was observed between MAO-B activity and the concentration of NE in AF. There was no correlation between EP concentrations and MAO activities. CONCLUSION: These results suggest that CA concentration in AF may be related to the activity of MAO in fetal membranes, determined by certain physiological processes during pregnancy. It has been suggested that metabolism of monoamines in fetal membranes also plays an important role in reducing monoamine influx into maternal myometrium from the AF.

Adult↗

PubMed1996

Postoperative staging of gastric carcinoma. A comparison between the UICC stage classification and the 12th edition of the Japanese General Rules for Gastric Cancer Study.

BACKGROUND: The feasibility of the latest edition of the Japanese General Rules for Gastric Cancer Study (GRGCS) is evaluated by comparison with the TNM system. METHODS: In a 5-year period from 1985 to 1989, 978 patients with gastric cancer underwent laparotomies at the Dept. of Gastroenterological Surgery, Aichi Centre Centre, Japan. All the patients have now been followed up for 5 years or until death. These patients were retrospectively classified into appropriate clinical stages and residual tumour status on the basis of the GRGCS and the 4th edition of the TNM classification by the UICC, and survival curves for various stages and subgroups were evaluated. RESULTS: The GRGCS classification provided useful information by splitting UICC stage IV into stages IVa and IVb, and R0 into curabilities A and B, both subgroups showing significant differences in the survival curves. CONCLUSIONS: The new edition of the GRGCS can be recommended as a useful staging manual for gastric cancer.

Follow-Up Studies↗

PubMed1996

Characterization of fibroblast growth factor-2 binding to ribosomes.

We have examined the binding of FGF-2 to ribosomes and have found that in NIH 3T3 cells that synthesize high amounts of all FGF-2 forms, both 18 kDa and HMW forms of FGF-2 bind to ribosomes. Ribosomes purified from these cells were treated with RNase or puromycin to identify the binding site of FGF-2 on the ribosome. Neither RNase nor puromycin treatment affected the in vivo binding of FGF-2 to ribosomes suggesting that FGF-2 binds ribosomal protein or rRNA, but not mRNA. The stoichiometry of binding in these cells was approximately 1 FGF-2 molecule bound per 1 ribosome. Binding was unaffected by high salt treatment indicating that FGF-2 tightly associates with polysomes. An in vitro binding experiment performed with purified ribosomes and recombinant FGF-2 suggested that the binding site is saturable. HBNF, a protein with similar charge and size to FGF-2, bound 15-fold less than FGF-2 to purified ribosomes. These results indicate that the binding of FGF-2 to ribosomes is specific.

3T3 Cells↗

PubMed1996

Dural arteriovenous fistula of the posterior fossa developing after surgical occlusion of the sigmoid sinus. Report of five cases.

In this article, the authors present five cases of dural arteriovenous fistula (AVF) that developed in the transverse-sigmoid sinus 2 to 6 years after sacrifice of the sigmoid sinus because of tumor involvement. The original tumor was meningioma in two patients and neurinoma, glomus jugulare tumor, and ameloblastoma in one patient each. The involved sigmoid sinus was resected along with the tumor and ligated at the normal edge; all that remained of the sigmoid sinus was a small stump on the retrosigmoid portion. Serial angiography performed before and after tumor surgery revealed no abnormal arteriovenous communications or dural AVF in any of the cases. Although many reports have suggested that sinus thrombosis is a precipitating factor in the pathogenesis of dural AVFs, this has been difficult to verify because of the small number of cases in which serial angiography was performed before the development of a dural AVF. In all of the cases presented in this article, surgical resection of a dural AVF and histological examination were performed. Subintimal fibrous thickening was marked, and the sinus wall was found to contain many dural vessels. Organized thrombosis with neovascularization was seen in only two patients. These cases demonstrate that subintimal fibrous thickening a hypertrophied sinus wall secondary to increased intrasinus pressure or sinus thrombosis occurring after sinus occlusion can provoke the development of a dural AVF within the course of a lifetime. Maintenance of intrasinus blood flow may be very important to prevent this late postoperative complication.

Arteriovenous Fistula↗