Biomedical subjects

M Satoh

Publications and source records attributed to M Satoh.

At least 901 records · Page 50Linked to original sources

PubMed1989

Idebenone and vinpocetine augment long-term potentiation in hippocampal slices in the guinea pig.

The effects of idebenone and vinpocetine which reportedly prevent impairment of learning and memory were studied in vitro, on the long-term potentiation of the population spike in the pyramidal layer of CA3 region of slices of hippocampus in the guinea pig. Idebenone (10(-9) M-10(-6) M) or vinpocetine (10(-7) M-10(-6) M) significantly augmented long-term potentiation in the mossy fibre-CA3 pyramidal cell system, without any significant changes in population spikes in the absence of tetanic stimulation. These results suggest that both drugs have direct actions on the hippocampal neurones to augment long-term potentiation at fairly small concentrations. Further, when the two drugs were applied together, the augmenting effects were additive.

2-Amino-5-phosphonovalerate↗

PubMed1989

Capsaicin-induced release of calcitonin gene-related peptide from dorsal horn slices is enhanced in adjuvant arthritic rats.

The capsaicin (3 microM)-evoked release of the immunoreactive calcitonin gene-related peptide (iCGRP) from dorsal-half slices of the rat lumbar spinal cord was substantially reduced in slices from rats which had undergone dorsal rhizotomy. This suggests that the release is elicited mainly from the nerve terminals of primary afferents. The release was significantly increased in slices from adjuvant arthritic rats compared with those from control rats. This suggests that the amount of iCGRP in a capsaicin-sensitive pool of the nerve terminals of primary afferents is elevated by adjuvant arthritis. Since adjuvant arthritis is known to cause an enhancement of biosynthesis and axonal flow of iCGRP in primary sensory neurons, the present results imply an increased release of iCGRP from the central terminals of the primary afferents in the adjuvant arthritic rat.

Animals↗

PubMed1989

Prevention of adverse effects of gamma-ray irradiation after metallothionein induction by bismuth subnitrate in mice.

The effect of preinduction of metallonthionein (MT) by bismuth subnitrate (BSN) on the adverse effects and antitumor activity of gamma-ray irradiation was investigated in mice. Preinduction of MT by oral administration of BSN significantly reduced the lethal effects and bone marrow injury caused by total body irradiation with gamma-rays. A significant increase in the MT concentration in bone marrow was observed in mice treated with BSN. In tumor-bearing mice, pretreatment with BSN did not compromise the antitumor activity of gamma-ray irradiation although bone marrow injury was remarkably suppressed. These results suggest that BSN pretreatment is an effective method for protection against side-effects in radiotherapy.

Adenocarcinoma↗

PubMed1989

Stimulus specificity of peripherally evoked substance P release from the rabbit dorsal horn in situ.

Characteristics of in situ substance P release from the lumbar dorsal horn were investigated in decerebrated rabbits. Noxious mechanical stimuli produced by pinching the skin of a hind leg ipsilateral to the perfusion site remarkably and significantly increased the release of immunoreactive substance P, which was identified as substance P itself, using separation with high-performance liquid chromatography and radioimmunoassay. The noxious pinch did not affect the release of immunoreactive substance P, when applied to the contralateral hind leg. Both the basal and pinch-evoked release of immunoreactive substance P were largest in the dorsolateral part of the dorsal horn. The pinch-evoked release of immunoreactive substance P was abolished when the dorsal horn was perfused with a Ca2+-free medium containing 7 mM Mg2+ or with a medium with 10 microM tetrodotoxin added. The evoked release of immunoreactive substance P was also abolished following pretreatment of a stimulated region with the local anesthetic dibucaine, a procedure which inhibited the pinch-evoked aversive behavior in freely-moving rabbits. Among a variety of natural stimuli applied to the hind leg, noxious pinch and a subcutaneous injection of formaldehyde solution significantly evoked the release of immunoreactive substance P from the dorsal horn. The most intense heat or scalding stimulation increased the immunoreactive substance P release in two out of five experiments. However, other natural stimuli such as ice-cold, warm, noxious heat and innocuous mechanical stimuli produced no apparent changes in the release of immunoreactive substance P. These results suggest that among the noxious stimuli, only mechanical and inflammatory but not thermal stimuli lead to a release of substance P from the primary afferent terminals in the dorsal horn. The present findings suggest that, at least in rabbits, substance P-containing primary afferents have high-threshold mechanoreceptors. Substance P may participate in the transmission of information related to noxious mechanical and inflammatory stimulation from the periphery to the dorsal horn.

Animals↗

PubMed1989

Carcinoid tumour of the middle ear.

Carcinoid tumours belong to the rarer neoplasms of the middle ear. In 1980, Murphy et al. described the first case of a carcinoid tumour of the middle ear. Only five cases could be traced in the literature. The light and electron microscope features of a primary atypical carcinoid tumour of the middle ear are presented and compared with those described in the literature. Primary carcinoid of the middle ear appears to be derived from the epithelial lining of the middle ear. Distant metastases have not been reported. The duration and nature of the symptoms are of little diagnostic value. An atypical carcinoid tumour in the left ear of a 33-year-old woman is described.

Adult↗

PubMed1989

Rubredoxin from Clostridium perfringens: complete amino acid sequence and participation in nitrate reduction.

The complete primary structure of rubredoxin (Rd) isolated from Clostridium perfringens was sequenced to be: MKKFICDVCGYIYDPAVGDPDNGVEPGTEFKDIPDDWVCPLCGVDKSQFSETEE. The sequence was highly homologous to that of C. pasteurianum Rd but was different at 13 sites out of the total 54 amino acid residues (76% homology). It contained 1 Fe atom, 4 cysteine residues, and no labile sulfur, had a molecular weight of 6,056, and shared the general properties of classical anaerobic Rds. The pI was 4.4. The Rd was reduced with NADH in the presence of a specific NAD(P)H oxidoreductase preparation from the bacterium. The Km value of nitrate reductase for Rd as an electron-donor was 12 microM, a value comparable to that of the 13 microM for ferredoxin (Fd). These results taken together provide additional support for its role as the electron carrier in the nitrate reductase system [Seki, S., Ikeda, A., and Ishimoto, M. (1988) J. Biochem. 103, 583-584].

Amino Acid Sequence↗

PubMed1989

Characterization of cysteine proteases functioning in degradation of dynorphin in neuroblastoma cells: evidence for the presence of a novel enzyme with strict specificity toward paired basic residues.

Two dynorphin-degrading cysteine proteases, I and II, were extracted with Triton X-100 from neuroblastoma cell membrane, isolated from accompanying dynorphin-degrading trypsin-like enzyme by affinity chromatography on columns of soybean trypsin inhibitor-immobilized Sepharose and p-mercuribenzoate-Sepharose, and separated by ion-exchange chromatography on diethylaminoethyl (DEAE)-cellulose and TSK gel DEAE-5PW columns. Cysteine protease II was purified further by hydroxyapatite chromatography and gel filtration. The molecular weights of cysteine proteases I and II were estimated to be 100,000 and 70,000, respectively, by gel filtration. Both of the enzymes, were inhibited by p-chloromercuribenzoate, N-ethylmaleimide, and high-molecular-weight kininogen, but not or only slightly inhibited by diisopropylphosphorofluoridate, antipain, leupeptin, E-64, calpain inhibitor, and phosphoramidon. Cysteine protease I cleaved dynorphin(1-17) at the Arg6-Arg7 bond with the optimum pH of 8.0, whereas II cleaved dynorphin(1-17) at the Lys11-Leu12 bond and the Leu12-Lys13 bond with the optimum pH values of 8.0 and 6.0, respectively. These bonds corresponded to those that had been proposed as the initial sites of degradation by neuroblastoma cell membrane. Cysteine protease I was further found to show strict specificity toward the Arg-Arg doublet, when susceptibilities of various peptides containing paired basic residues were examined as substrates for the enzyme.

Animals↗

PubMed1989

Electrophysiologic evaluation of asymptomatic patients with the Wolff-Parkinson-White pattern.

In the past 4 years, 34 asymptomatic patients with the Wolff-Parkinson-White (WPW) pattern underwent electrophysiologic study. The effective refractory period (ERP) of antegrade conduction over the accessory pathway was 288 +/- 29 msec. In three asymptomatic patients (9%), the antegrade ERP of the accessory pathway was shorter than 250 msec. The antegrade ERP of the accessory pathway became shorter than 250 msec in an additional 12 of 22 (55%) patients after isoproterenol administration. Nineteen (56%) of the asymptomatic patients showed the absence of retrograde conduction over the accessory pathway even after isoproterenol administration. The rate of induction of orthodromic reciprocating tachycardia in the asymptomatic WPW patients was 15% (5/34), which was significantly lower than that in the symptomatic patients. These data suggest that in the asymptomatic patients, the absence of retrograde conduction over the accessory pathway is the reason they remained asymptomatic, free of reciprocating tachycardia. However, even in the asymptomatic patients, some had the accessory pathway in which antegrade ERP was shorter than 250 msec. They may result in rapid ventricular conduction over the accessory pathway when atrial fibrillation develops.

Adult↗

PubMed1989

Fusion with the prolonged first postpacing interval in pacing of ventricular tachycardia.

In cases of recurrent sustained ventricular tachycardia (VT), constant fusion and progressive fusion in the surface electrogram were observed during overdrive pacing of VT. However, following cessation of pacing, the return cycle of VT (stimulus to the first nonpaced QRS) was longer than the VT cycle length. This phenomenon can be explained by orthodromic capture of the exit site of the VT current with a conduction time (stimulus to QRS) exceeding the VT cycle length. This site can therefore be activated during entrainment of VT during the mid-to-terminal portion of the paced QRS complex, resulting in constant fusion.

Cardiac Pacing, Artificial↗

PubMed1989

Characterization of the Schizosaccharomyces pombe ral2 gene implicated in activation of the ras1 gene product.

Mutations in the Schizosaccharomyces pombe ral2 gene cause a phenotype indistinguishable from that of the ras1-defective mutant. Using cloned ral2 DNA, we disrupted the chromosomal gene. The disruptants showed the same phenotype as the original ral2 isolates, i.e., they had spherical cells, had no detectable mating activity, and exhibited no response to the mating pheromone, but their vegetative growth was apparently normal. Sequence analysis of the ral2 gene suggests that it encodes a polypeptide of 611 amino acid residues whose predicted amino acid sequence shows no strong homology to any known protein. Either multiple copies or even a single copy of the ras1Val-17 allele, which is an activated form of ras1, restored rodlike cell morphology and ability to respond to the mating factor to ral2 mutants. These results suggest that the ral2 and ras1 gene products interact intimately and that the ral2 gene product is involved in activation of the ras1 protein in S. pombe.

Alleles↗

PubMed1989

Harderianization is another sexual dimorphism of rat exorbital lacrimal gland.

The exorbital lacrimal glands (ELG) of rats were examined for both sexes to determine what degree of harderianization occurred as a function of age and after castration, and to investigate its time course and origin in ELG. Light microscopically, very small Harderian foci were seen in the ELG of both sexes at 3 weeks of age. As the male rats became older, the relative volume of the Harderian gland (HG) cells in the ELG increased. At age 6 months, the value was 1.25 +/- 0.31% in males and 0.13 +/- 0.05% in females (p less than 0.05). After castration, a significant decrease (0.21 +/- 0.01%, p less than 0.05) was observed in that of male ELG. In contrast, in female ELG, HG cells were inconspicuous and the relative volume of those did not vary during this experimental period or after castration. It appeared that the HG cells had developed from undifferentiated basal cells of the acini and the intercalated ducts in the ELG at age 2-6 months. Then, at age 22 months, they also probably developed from those of the excretory ducts of the ELG.

Aging↗

PubMed1989

Optimum schedule of selenium administration to reduce lethal and renal toxicities of cis-diamminedichloroplatinum in mice.

The optimum conditions of selenium administration to reduce the side effects of a single dose of cis-diamminedichloroplatinum (cis-DDP) in mice were examined. The best effects against lethal toxicity of cis-DDP was obtained when sodium selenite was administered subcutaneously (s.c.) to mice simultaneously with s.c. injected cis-DDP at a molar ratio of 1 to 3.5 (sodium selenite to cis-DDP) on the first day and the same amount of selenite was given daily for four subsequent days. This coadministration of selenite completely depressed not only lethal toxicity of cis-DDP but also its renal toxicity (indicated by increased blood urea nitrogen values) and intestinal toxicity (indicated by the incidence of diarrhea) which were usually observed in the mice treated with cis-DDP alone. Furthermore, coadministration of selenite did not compromise the antitumor activity of cis-DDP against several transplantable tumors in mice. Therefore, the administration schedule of selenite with cis-DDP described above may be useful for cancer chemotherapy.

Animals↗

PubMed1989

Indeloxazine augments long-term potentiation in the mossy fiber-CA3 system of guinea pig hippocampal slices.

The effects of indeloxazine and piracetam, which reportedly prevent experimental impairments of memory and learning, on long-term potentiation (LTP) of the population spike in the mossy fiber-CA3 system were studied in vitro using the guinea pig hippocampal slices. Indeloxazine (10(-6) M) or piracetam (10(-4) M) significantly augmented the LTP and the effect of indeloxazine on the LTP was approximately 100 times as potent as that of piracetam.

Animals↗

PubMed1989

Histological evidence of left ventricular involvement in arrhythmogenic right ventricular dysplasia.

A 40-year-old female with arrhythmogenic right ventricular dysplasia (ARVD) demonstrated a reduced motion of the left ventricular (LV) apex. Specimens of LV free wall, obtained by endomyocardial biopsy, histologically revealed prominent interstitial fibrosis with sparse distribution of myocytes. The myocytes were hypertrophic and disrupted with loss of myofibrils. This is a case of ARVD, where LV involvement was histologically verified.

Adipose Tissue↗

PubMed1989

Sustained ventricular tachycardia responsive to verapamil in patients with hypertrophic cardiomyopathy. Clinical and electrophysiological assessment of drug efficacy.

Recently, we examined 2 cases of hypertrophic cardiomyopathy (HCM) presenting with sustained ventricular tachycardia (VT). One case was a 62 year old male with midventricular hypertrophy and monomorphic sustained VT. After admission, the efficacies of procainamide, disopyramide, aprindin, flecainide, mexiletine and verapamil were evaluated by means of continuous electrocardiographic monitoring. Verapamil prevented the recurrence of sustained VT and markedly reduced the frequency and number of runs of nonsustained VT. In the electrophysiologic study, rapid VT was induced by double extrastimuli at the right ventricular apex. Intravenous verapamil at a dose of 10 mg prevented the induction of VT. The patient was discharged on verapamil and remains asymptomatic after 3 months of follow up. The other case was a 34 year old female who was a survivor of cardiac arrest. Monomorphic VT was observed on emergency admission and was converted to sinus rhythm by direct current cardioversion after resuscitation. In the electrophysiologic study, rapid VT was induced by double extrastimuli at the right ventricular outflow tract. Verapamil at a dose of 10 mg prevented the induction of VT. These 2 cases of HCM are rare in that they presented with sustained VT. It is also of interest that verapamil, which has been used conventionally in HCM, prevented VT.

Adult↗

PubMed1989

[Evaluation of recurrent metastatic brain tumor of lung cancer origin].

The authors examined numerous clinical features in 15 patients in whom brain metastases from lung cancer recurred after total or subtotal removal. The incidence of recurrence after initial removal of brain nodules was 46.9% (15 of 32 cases). There was no significant correlation between the incidence of recurrence and the histology of the lung cancer, the site of brain nodules, or age. Recurrent brain nodules were the cause of or contributed to death in 60% of recurrent cases. Recurrence was within 3 months of initial removal of brain nodules in 10 of the 15 patients. Brain metastasis recurred only at the initial site in 11 cases (73.3%). Three patients developed carcinomatous meningitis and one had multiple metastases in addition to recurrence or regrowth at the original site. The primary lung cancer was relatively stable at the time of recurrence of brain nodules in 60% of the patients. Tumor removal and radiotherapy are highly recommended for prevention of early recurrence following initial removal of brain metastases. Removal of metastatic tumor is advised in the event of recurrence after 1 year from initial surgery, since the outcome after second surgery tends to be fair. However, tumor removal and radiotherapy are sometimes capable of inducing recurrence of brain nodules. Therefore, it is hoped that more effective cancer chemotherapy will be developed in the near future.

Adenocarcinoma↗

PubMed1989

[Effect of recombinant human granulocyte colony-stimulating factor on white blood cell count and neutrophil functions in patients with malignant lymphoma].

We studied the in vivo effects of recombinant human granulocyte colony-stimulating factor (rhG-CSF) on white blood cell (WBC) count and neutrophil functions in nine patients with malignant lymphoma. The WBC count and absolute neutrophil count were rapidly increased without a nadir phase after chemotherapy. Neutrophil alkaline phosphatase (NAP) scores also markedly increased following chemotherapy in all patients. Phagocytosis of India ink and nitroblue tetrazolium (NBT) reduction were revealed tend to be increased, but not exceeded significantly to normal range. RhG-CSF repaired neutrophil function in patients with decreasing that. Thus, rhG-CSF may be useful for prevention and treatment of infection after chemotherapy.

Adult↗

PubMed1989

[Study on the formation of fluorapatite with freeze-drying silicahydro gel method].

Resultant products and gel substance, formed with silicahydro gel method as well as with freeze-drying silicahydro gel method by use of tray, were compared and examined to materialize clinical application of gel method easily and the following results were obtained: 1. Evaluation of gel substance in control group gel (silicahydro gel) and in experimental group gel (gel prepared by the addition of deionized water to freeze-drying silicahydro gel) As the results of measuring the estimation of F- by ion chromatography and pH value, no clear-cut distinction between control group gel and experimental group gel was recognized, however, it was implied by naked-eye observations and through scanning electron microscope with the passage of time that experimental group gel had been inferior to control group gel. 2. Evaluation of resultant products in control group gel (resultant products formed with silicahydro gel method) and in experimental group gel (resultant products formed with freeze-drying silicahydro gel method) Naked-eye observations of reacting progress, the pH measurements, the calculation of Ca/P ratio, qualitative analyses by X-ray diffraction (reference; the measurements of crystallite size, lattice imperfection and lattice constant) and composition analyses by infrared absorption spectrum were carried out and as the results, resultant products in control group gel proved to be more favorable than those in experimental group gel. From the foregoing outcomes, it was suggested that fluorapatite of favorable crystallinity had been possible to be produced more with silicahydro gel method than with freeze-drying silicahydro gel method, and that further investigation inclusive of gel substance would be required in the event of clinically applying freeze-drying silicahydro gel method effectively.

Apatites↗