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T Iijima

Publications and source records attributed to T Iijima.

At least 253 records · Page 14Linked to original sources
PubMed1995

[Anesthetic management of a patient with cardiac sarcoidosis].

We report the anesthetic management of a patient with cardiac sarcoidosis. Cardiac sarcoidosis is characterized by a high incidence of complete atrioventricular block, right bundle branch block, and ventricular arrhythmias. Cases of sudden death during stable cardiac function have been reported. Therefore, careful anesthetic management is necessary. The patient was premedicated with scopolamine, intramuscularly. Before the induction, he received lidocaine, propranolol, and pentazocine, intravenously. Anesthesia was induced with midazolam and vecuronium, and the trachea was intubated. Anesthesia was maintained with nitrous oxide, sevoflurane in oxygen. Anesthetic method adapted to prevent severe complications including sudden death resulted in good condition of the patient during the perioperative period.

Adult↗
PubMed1994

Signal transmission in the parallel fiber-Purkinje cell system visualized by high-resolution imaging.

We investigated the synaptic transmission in the parallel fiber-Purkinje cell system at high spatio-temporal resolution by using voltage-sensitive dyes and an imaging system. In rat cerebellar slices, cut in the frontal plane or in a plane of the cerebellar surface, local electrical stimulation induced volleys of action potentials in the parallel fibers; subsequent postsynaptic responses from Purkinje cells were observed along the volleys' entire trajectories. Furthermore, the formation of an ordered spatial gradient in parallel fiber conduction velocity across the depth of the molecular layer during postnatal development was observed. In preparations of adult, but not of immature rats, the conduction velocity of parallel fibers in the deep molecular layer was faster than in its more superficial regions. Our observations demonstrate that parallel fibers can mediate Purkinje cell excitation effectively and over considerable distances in a well-organized spatio-temporal manner, thus supporting the classical view of the physiological role assigned to the parallel fibers.

Action Potentials↗
PubMed1994

Novel cell-surface Ag expressed on rat osteoclasts regulating the function of the calcitonin receptor.

Osteoclasts are known to be hematopoietic in origin. However, the detailed mechanisms of their differentiation and activation are not known. Cell-surface molecules preferentially expressed on cells of the osteoclast lineage may play some important roles in these processes. We prepared a mAb that recognizes a unique cell-surface membrane protein specifically expressed on rat osteoclasts. Expression of this Ag, designated as Kat1 Ag, was markedly stimulated by a factor secreted by the osteoblastic cell line ROS 17/2.8. Binding studies of 125I-labeled calcitonin (CT) showed that the Ag was not the CT receptor (CTR). However, interestingly, studies of the biologic activity of this mAb that recognizes Kat1-antigen (mAb Kat1) revealed possible regulatory functions of this Ag in osteoclasts. Firstly, mAb Kat1 significantly elevated the binding affinity of the CTR expressed on osteoclast-like cells without altering the number of receptors. Secondly, CT-sensitivity of the osteoclast progenitor cells in the system of osteoclast differentiation showed marked augmentation on treatment of these cells with this mAb. Even a very low concentration of CT (0.1 ng/ml) significantly inhibited osteoclast differentiation in the presence of mAb Kat1, whereas a higher concentration of CT (10 ng/ml) was required to inhibit their differentiation in the absence of this mAb. Thirdly, mAb Kat1 inhibited dentin-resorbing activity of osteoclast-like cells. Furthermore, the inhibitory effects of CT on osteoclast-mediated dentin resorption was augmented by the presence of this mAb. These observations strongly suggest that Kat1-antigen is a unique cell-surface protein regulating the affinity of the CTR expressed on osteoclasts and also the bone-resorbing function of these cells.

Animals↗
PubMed1994

Retinobenzoic acids. 6. Retinoid antagonists with a heterocyclic ring.

Several candidate retinoid antagonists were designed on the basis of the ligand superfamily concept and synthesized. Retinoidal activities of these benzimidazole and benzodiazepine derivatives were examined by assay of differentiation-inducing activity on human promyelocytic leukemia cell line HL-60. The parent benzimidazole derivative, 4-(5,6,7,8-tetrahydro-5,5,8,8- tetramethylnaphth-[2,3-d]imidazol-2-yl)benzoic acid (7a), and related compounds with a small alkyl group instead of the hydrogen on the nitrogen (1N) atom of the imidazole ring exhibited retinoidal activity, and the potency strongly depended on the bulkiness of the substituent. The compounds having a phenyl or benzyl group on the nitrogen lacked differentiation-inducing activity on HL-60 cells and acted as antagonists to the potent retinoid 4-[(5,6,7,8-tetrahydro-5,5,8,8- tetramethyl-2-naphthalenyl)carbamoyl]benzoic acid (Am80). Among the compounds possessing a seven-membered heterocyclic ring as a linking group, 4-(5H-7,8,9,10-tetrahydro-5,7,7,10,10- pentamethylbenzo[e]- naphtho[2,3-b][1,4]diazepin-13-yl)benzoic acid (16) also exhibited the antagonistic activity. The binding abilities of these compounds to retinoic acid receptors alpha and beta were consistent with their potency for the inhibition of HL-60 cell differentiation induced by the retinoid Am80.

Benzimidazoles↗
PubMed1994

Chloride-sensitive Ca2+ entry by histamine and ATP in human aortic endothelial cells.

The regulation of intracellular free Ca2+ concentration ([Ca2+]i) was studied in cultured human aortic endothelial cells loaded with the fluorescent Ca2+ indicator fura-2. Histamine and ATP at concentrations of 10 microM and higher produced a biphasic change in [Ca2+]i, which consisted of an initial transient elevation followed by a sustained elevation. Reduction of the extracellular Cl- concentration to 40 mM, or exposure to the Cl- channel antagonist N-phenylanthranilic acid selectively prevented the sustained response to histamine or ATP, but they did not affect the sustained response to the Ca2+ ionophore ionomycin. Elevation of extracellular K+ concentration to 90 mM had no influence on the sustained response to histamine or ATP. These results suggest that the sustained elevation of [Ca2+]i in response to histamine and ATP is due to the Cl(-)-sensitive entry of extracellular Ca2+ in cultured human aortic endothelial cells.

Adenosine Triphosphate↗
PubMed1994

A novel monoclonal antibody recognizing a unique antigen of rat osteoclasts induced by the calcified matrices.

The morphology of osteoclasts, primary cells that resorb bone, is well documented; however, the precise details of their terminal differentiation remains obscure. To date, the only morphological criterion for identifying activated functional osteoclasts has been the presence of ruffled borders. We have developed a rat bone marrow culture system in which osteoclast-like cells formed. These cells fulfilled most of the criteria of osteoclasts, and when they were reseeded on calcified tissue, formed numerous resorption lacunae in vitro. To find an immunological marker for functional osteoclasts, we have used these cells in a functional state as antigens for the preparation of monoclonal antibodies (mAb) that reacted with rat osteoclasts; we obtained mAb Ch1 and Ch2. Interestingly, these mAbs reacted with the marginal portion of authentic osteoclasts, where they attached to the bone surface on frozen sections. The reactivity of Ch1 to rat osteoclasts was more restricted than that of Ch2: Ch1 reacted with few tartrate-resistant acid phosphatase (TRAP)-positive cells on a culture plate. These TRAP-positive cells (including mono- and multinucleated cells) were, however, converted to Ch1-positive cells when they were reseeded on calcified tissues. These findings suggested that the antigen recognized by the Ch1 antibody was induced by some factors of matrix proteins released from calcified tissues.

Acid Phosphatase↗
PubMed1994

Localization of osteopontin in resorption lacunae formed by osteoclast-like cells: a study by a novel monoclonal antibody which recognizes rat osteopontin.

The characteristics of a monoclonal antibody produced against osteoclast-like multinucleated cells (MNCs) formed in rat bone marrow cultures were examined immunohistochemically and biochemically. The in vitro immunization was performed using as immunogen the MNCs from rat bone marrow cell culture, which revealed many characteristics of osteoclasts. After screening and cloning of hybridomas, the monoclonal antibody HOK 1 was obtained. This antibody reacted weakly with stromal cells and intensely with both MNCs and their putative migratory traces on culture dishes. Immunofluorescent examination of paraffin sections revealed intense reactivity on the epithelium of the choroid plexus, the ileum and the proximal-convoluted tubules of the kidney, and also on bone cells such as osteocytes, osteoblasts, and osteoclasts. Western blotting using purified rat osteopontin verified that the antigen recognized by HOK 1 was osteopontin. Positive HOK 1 immunoreactivity was further observed in the resorption lacunae formed by a culture of MNCs on human tooth slices and on the surface of osteoclasts. The present data suggested that osteopontin is preferentially present on the resorption lacunae in resorbing calcified matrices and that osteoclasts under a specific state might trap this protein on their cell surface.

Animals↗
PubMed1994

A randomized trial of intrahepatic arterial infusion of 4'-epidoxorubicin with Lipiodol versus 4'-epidoxorubicin alone in the treatment of hepatocellular carcinoma.

We conducted a prospective randomized trial to evaluate the efficacy of Lipiodol in intrahepatic arterial infusion chemotherapy for patients with hepatocellular carcinoma (HCC). A total of 38 patients with unresectable HCCs and underlying cirrhosis were entered in this trial, and 36 of them were evaluable. Every 4 weeks, 17 patients received 70 mg of 4'-epidoxorubicin (epirubicin) alone (group A), whereas 19 patients received a Lipiodol emulsion containing the same dose of epirubicin (group B) through the hepatic artery. A tumor response (CR+PR) was observed in 12% of group A patients and in 42% of group B patients. The group B patients showed a significantly higher response rate than the group A patients. There was a tendency for an increased duration of survival (P = 0.09) in the group B patients. These results suggested that the infusion of the Lipiodol emulsion with epirubicin was more effective than epirubicin alone for the treatment of these patients with HCC.

Aged↗
PubMed1994

High-yield induction of uterine endometrial adenocarcinomas in Donryu rats by a single intra-uterine administration of N-ethyl-N'-nitro-N-nitrosoguanidine via the vagina.

A total of 130 female Donryu rats (10-week-old) were divided into two groups; 80 animals in the experimental group were given a single intra-uterine administration of 20 mg/kg N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) dissolved in polyethylene glycol (PEG) via the vagina without laparotomy, and 50 animals in the control group received PEG alone in the same manner. Small numbers of animals in both groups were killed at 3, 6, 9 and 12 months after ENNG treatment for sequential histological and endocrinological examination, and at 12.5 experimental months (15 months of age) all survivors were killed. At the termination, endometrial adenocarcinomas were present in 49% of the experimental group, compared to 0% in the control group. Severe endometrial hyperplasias were also found only in the experimental group and sequential histological examination showed first appearance of hyperplasia at 6 months and adenocarcinoma at 9 months. No tumors other than uterine carcinomas were induced by ENNG and the carcinogen treatment did not affect the endocrine environment of rats, persistent estrus appearing at 6 months after the start and increasing with age in both groups. The estradiol-17 beta:progesterone (E:P) ratio was also increased after 6 months, with further elevation at 12 months to about 8 times higher than the level at 6 months. These results indicate that an increased E:P ratio might act as a promoter of development of endometrial proliferative lesions initiated by ENNG in this rat strain. The study indicates that the present simple method using Donryu rats provides a good animal model for endometrial adenocarcinoma development in women.

Adenocarcinoma↗
PubMed1994

Differential modulation by adenylate cyclase of Ca2+ and delayed K+ current in ventricular myocytes.

This study was designed to investigate the differential modulation of the L-type Ca2+ (ICa) and the delayed rectifier K+ (IK) currents by direct activation of adenylate cyclase in guinea pig ventricular preparations. Action potentials were measured with conventional microelectrodes in excised papillary muscles. Isoproterenol significantly shortened the action potential duration at 90% repolarization (APD90) at 0.1 nM but significantly prolonged it at a higher concentration (10 nM). A water-soluble forskolin derivative, 6-(3-dimethylaminopropionyl) forskolin (NKH-477), slightly but significantly shortened APD at 12 nM but not at a higher concentration (120 nM). Effects of isoproterenol and NKH-477 on ICa and IK were also investigated by use of the whole cell voltage-clamp technique in single ventricular cells. Isoproterenol increased not only IK but also ICa at the same threshold concentration (0.3 nM). In contrast, the threshold concentration of NKH-477 for increasing IK (approximately 1 nM) was clearly lower than that for increasing ICa (10 nM). These results indicate that ICa and IK channels could be differentially regulated during beta-adrenoceptor stimulation.

Action Potentials↗
PubMed1994

Detection of glycosylated protein in renal tissues and dermal vascular vessels in the microalbuminuric stage of diabetic nephropathy using the nitro blue tetrazolium reaction.

Detection of glycosylated protein in renal and dermal tissues was performed in patients in the microalbuminuric stage of diabetic nephropathy using the nitro blue tetrazolium (NBT) reaction. The intensity of NBT staining in glomeruli and dermal vascular vessels was marked in the microalbuminuric stage as well as in the overtly proteinuric stage. The NBT staining in the renal and dermal vascular walls in both stages was significantly stronger than in the samples of control autopsy patients. It appeared that nonenzymatic glycosylation in various tissues, i.e. kidneys and dermal vascular vessels, had already progressed in the microalbuminuric stage in patients with diabetic nephropathy.

Adult↗
PubMed1994

Postnatal changes in mRNA expression of the K+ channel in rat cardiac ventricles.

The reason for the postnatal changes of action potential duration in rat heart cells is still a matter of controversy. We have examined mRNA expression levels of Kv1.2, one of the K(+)-channel genes, in neonatal (1 week) and adult (8 weeks) rat cardiac ventricles. For analysis of mRNA expression, we used the reverse transcription-polymerase chain reaction method. The level of Kv1.2 mRNA expression in adult rats was significantly higher than that in neonatal rats. This result suggests that the levels of ion channel gene expression may be responsible for the postnatal changes of the action potential duration.

Action Potentials↗
PubMed1994

[The transverse submammary skin incision for median sternotomy].

Median sternotomy is the incision of choice to allow access to the anterior mediastinum, heart or both lungs. The vertical skin incision is cosmetically unsatisfactory for many female patients. The transverse submammary skin incision with dissection of a flap including the subcutaneous tissue and breasts allow exposure of the sternum for a median sternotomy. Seventy patients with the transverse submammary skin incision was compared with 56 patients with the vertical skin incision in the point of the cosmetic aspect and satisfaction of patients. The transverse submammary skin incision needed a longer wound size and took a longer time for cardiopulmonary bypass, but there were no difficulties in cannulating the ascending aorta for cardiopulmonary bypass. The exposure of the mediastinum and the cosmetic result were excellent. The complications associated with this incision are insignificant if close attention is paid to details.

Adolescent↗
PubMed1994

[Advanced breast cancer with remarkable response to the combination therapy of mitoxantrone (MIT) and medroxyprogesteron acetate (MPA) after failure of anthracycline therapy: a case report].

A 67-year-old advanced breast cancer patient with multiple bone metastases showed a remarkable response to the combination therapy of mitoxantrone (MIT) and medroxyprogesteron acetate (MPA) after failure of anthracycline therapy. Eight course of CTF (cyclophosphamide, THP-adriamycin, 5-fluorouracil) and subsequent 4'-epi-adriamycin were performed for locally advanced breast cancer and multiple bone metastases, but the ulcerated breast cancer enlarged. Then the combination therapy of MIT (10 mg/day) and MPA (1,200 mg/day) was carried out. Seven months after treatment, the ulcerated breast cancer disappeared completely and the serum levels of CA 15-3, TPA and CEA decreased within the normal range. These results suggest that combination therapy with mitoxantrone may well be effective against the anthracycline-resistant breast cancer.

Aged↗
PubMed1993

Brain resuscitation by extracorporeal circulation after prolonged cardiac arrest in cats.

OBJECTIVE: Brain reanimation after prolonged ischemia is limited by post-ischemic reperfusion deficits (no-reflow phenomenon). The present study was undertaken to establish whether after 30 min cardiac arrest extracorporeal circulation is able to restore brain reperfusion and to promote functional and metabolic recovery. DESIGN: Adult normothermic cats were submitted to 30 min cardiac arrest by KCl-induced cardioplegia. Resuscitation was carried out by extracorporeal circulation (ECC) until spontaneous heart function returned. The quality of brain recovery was assessed 3 h later by electrophysiological recording and by imaging of the regional distribution of brain energy metabolites. RESULTS: In 6 of 10 cats cardiac sinus rhythm returned after 32 +/- 15 min. In the other 4 cats cardiac function did not return or only intermittently returned during the 3 h observation period. Cerebral blood flow measured by laser Doppler flowmetry returned to 102% +/- 40% of control immediately after the beginning of resuscitation but then gradually declined to 43% +/- 32% after 3 h despite normotensive perfusion. In all cats pupils started to constrict within less than 5 min of recirculation but in 2 animals they secondarily dilated 1.5 and 2 h later, respectively. Spontaneous EEG activity reappeared in 4 of the 6 successfully resuscitated cats after 111 +/- 40 min but failed to recover in the others. Bioluminescent imaging of ATP after 3 h recirculation revealed near-complete depletion throughout the brain in all 4 cats without cardiac recovery. Of the 6 successfully resuscitated cats 5 exhibited patchy areas of low ATP, glucose and pH in 22%-92% of the cross sectional area of brain; in one cat recovery of energy metabolism and acid-base homoeostasis was homogeneous without any focal deficits. The cross sectional area of ATP recovery correlated directly with CBF and hematocrit and inversely with the plasma lactate level. CONCLUSIONS: This study demonstrates for the first time that ECC is able to restore electrophysiological and metabolic brain function after cardiac arrest of as long as 30 min, but recovery is heavily restricted by delayed post-ischemic disturbances of recirculation. Progress in cardiac resuscitation by ECC requires substantial improvement in the efficiency of cerebrovascular reperfusion.

Acid-Base Equilibrium↗
PubMed1993

Scanning electron microscopic observation of the vascular wall cells in human dental pulp.

The following six vascular segment types were identified in human dental pulp based on morphological differences in the periendothelial cells: (a) muscular arterioles with at least two compact layers of smooth muscle (SM) cells; (b) terminal arterioles with at least one compact muscle layer; (c) precapillary arterioles with an incomplete muscle layer; (d) capillaries with scattered pericytes; (e) postcapillary venules with clustered pericytes; and (f) muscular venules with at least one layer of flattened SM cells. In almost all muscular and terminal arterioles, the surface of SM cells showed marked to slight irregularities indicating vasoconstriction apparently caused by local administration of anesthetic containing epinephrine. Flattened SM cells in muscular venules also showed surface irregularities. SM cells in precapillary arterioles and pericytes in capillaries and most postcapillary venules, however, showed no distinct features of constriction.

Adolescent↗