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Biomedical subjects

T Tsujimoto

Publications and source records attributed to T Tsujimoto.

At least 91 records · Page 5Linked to original sources
PubMed1988

Calcitonin gene-related peptide prevents disuse-induced sprouting of rat motor nerve terminals.

Calcitonin gene-related peptide (CGRP) coexists with acetylcholine (ACh) in motor nerve terminals. Externally applied CGRP has been shown to increase the synthesis of ACh receptors in cultured myotubes by a mechanism independent of muscle activity. Thus, CGRP is suggested to be a neurotrophic factor that may regulate the expression of several long-term events occurring at the neuromuscular junction. We have examined the effect of CGRP on the sprouting of motor nerve terminals induced by chronic block of nerve-muscle activity in adult rats. Daily treatment with CGRP suppressed the disuse-induced terminal sprouting in a dose-dependent manner, whereas the morphology of motor nerve terminals in active muscles was unaffected by CGRP. CGRP may be a possible candidate for an antisprouting agent which has been postulated to exist in nerve terminals. The disuse-induced outgrowth of terminal sprouts was accompanied by an increase in the mean quantum content of end-plate potentials, as well as in the frequency of spontaneous miniature end-plate potentials. This increased transmitter release was still maintained at the junctions in which disuse-induced terminal sprouting had been suppressed by CGRP. It is suggested that the formation of terminal sprouts per se is not responsible for the plastic change of transmitter release induced by prolonged disuse of the neuromuscular junction.

Animals↗
PubMed1986

Pathway of the blink reflex in the brainstem of the cat: interneurons between the trigeminal nuclei and the facial nucleus.

Blink reflex responses evoked by electrical stimulation of the supraorbital nerve were examined using cats and the pathway of the blink reflex in the brainstem was elucidated. Both early response (ER) and late response (LR) were mediated by the main sensory trigeminal nucleus and the spinal trigeminal nucleus. However, a lesion of the main sensory trigeminal nucleus had less effect on the blink reflex than a lesion of the spinal trigeminal nucleus. The ER was mediated not only by the shorter disynaptic pathway of 3 neurons through the trigeminal nerve, the trigeminal nuclei and the facial nucleus but also by a polysynaptic pathway of 4 neurons. The interneurons were located between the trigeminal nuclei and the facial nucleus. Some of these interneurons participated in the production of both ER and LR. The area of the brainstem responsible for ER and LR of the blink reflex was the reticular formation from the rostral part of the medulla to the pons except the medial area around the median sulcus. The LR interneurons were distributed more widely than the ER interneurons.

Animals↗
PubMed1986

Influence of voltage and ATP on ion-channel of (Na,K)ATPase incorporated into solvent-free phospholipid planar bilayers.

Purified (Na,K)ATPase was incorporated into solvent free phospholipid bilayers made on patch-clamp pipettes. In the absence of ATP, the incorporated enzyme acted as an ion-channel which underwent opening and closing (switching) upon application of transmembrane potential gradient of more than 40 mV. The minimum conductance was about 40 pS. It was inhibited by ouabain from one side. ATP added to the opposite side shifted the threshold potential for switching of the channel to 80 mV. Furthermore the magnitude of minimum conductance decreased to 6-10 pS in the presence of ATP.

Adenosine Triphosphate↗
PubMed1984

Monocular movement of contralateral eye following cortical stimulation in the coronal sulcus of cat.

Monocular movements of the contralateral eye were demonstrated following the stimulation of the internal kneelike portion of the cortex in the coronal sulcus of the cat. The stimulation of this cortical area in the coronal sulcus yielded rapid medial or slightly oblique ventromedial movement of the contralateral eye. While ablation of the same cortical area produced contralateral eye shift toward the dorsolateral side and the shifted eye became uncontrollable. The results suggested that the control mechanism of eye movement involves unilateral innervation system to the contralateral side as seen in the extremities.

Animals↗
PubMed1984

Transuncodiscal approach to dumbbell tumors of the cervical spinal canal.

A combined anterior and lateral approach to the anterior cervical spinal canal with fusion was performed on five patients with cervical dumbbell-shaped tumors. The procedure consists of anterior discectomy and ipsilateral uncectomy, and removal of the posterolateral corners and posterior transverse ridges of the upper and lower vertebral bodies at the level of the tumor. In the case of a large tumor in the spinal canal, additional removal of a limited segment from the lateral part of the vertebral body was performed. The bone defect was filled with a T-shaped iliac bone graft. Two vertebral bodies were fused in each case. The highest level of the operation was C-2 and the lowest was T-1. The authors believe that any cervical dumbbell-shaped tumor below the C-2 level can be removed via an anterolateral approach as long as no more than three levels of the spine are involved.

Adult↗
PubMed1983

Electron spin resonance studies on the selective labeling of N-(1-oxyl-2,2,5,5-tetramethyl-3-pyrrolidinyl)maleimide of rat liver mitochondria.

N-(1-Oxyl-2,2,5,5-tetramethyl-3-pyrrolidinyl)maleimide (MSL) was incorporated into rat liver mitochondria and the nitroxide radical incorporated was found to decay considerably. The incorporation was blocked by a high concentration of NEM, but not by pCMB. Spin labeled fatty acid derivatives, 2-(3-carboxypropyl)-2-tridecyl-4,4-dimethyl-3-oxazolidinyloxyl (FSL1) and 2-(14-carboxytetradecyl)-2-ethyl-4,4-dimethyl-3-oxazolidinyloxyl (FSL2), were also incorporated and the nitroxide radical decayed. However, incorporation of FSL1 or FSL2 was not blocked by NEM or pCMB. The ESR spectrum of 3-carboxyl-2,2,5,5-tetramethyl-pyrroline-1-oxyl (CSL) did not change on reaction with the mitochondria. The labeled MSL exhibited an ESR spectrum composed of both strongly immobilized and weakly immobilized components. A similar reaction with FSL1 gave an ESR spectrum mainly composed of a strongly immobilized component, the weakly immobilized component was negligibly small, while FSL2 exhibited an ESR spectrum in which free-like signals of the nitroxide radical were predominant. The results suggest that MSL is labeled selectively in the mitochondrial membrane through those SH groups that are not reactive to pCMB, and the labeled nitroxide radical is reduced in situ. The mode of incorporation into the mitochondria differs between MSL and the other spin labeled reagents, and labeling of MSL at the binding site may precede reduction of the nitroxide radical. The incorporation of MSL was dependent on the concentration of MSL used. ADP-acceleration of mitochondrial oxygen uptake with succinate was inhibited by labeling the mitochondria with MSL without loss of the electron transferring activity.

Animals↗
PubMed1983

Eye movements evoked by electrical stimulation of the frontal cortex in the coronary sulcus of the cat.

The frontal cortex concerned with eye movements was investigated by electrical stimulation in the cat. Stimulation of the lateral part of the frontal cortex at the coronary sulcus evoked rapid medial movement and enophthalmos of the contralateral eye. The latency of eye movement following cortical stimulation was found to be shorter in the coronary sulcus than in the medial wall of the hemisphere under the cruciate sulcus or in the presylvian sulcus.

Animals↗
PubMed1983

Combined therapy for maxillary sinus carcinoma with special reference to cryosurgery.

Three hundred cases of maxillary sinus carcinoma were divided into four groups according to the initial treatment: the first group was treated by irradiation of 5,000 rad (25 fractions) for 5 weeks; the second by intra-arterial infusion of 5-FU combined with irradiation; the third by sinus curetting in accordance with Denker's operation combined with the second method; and the fourth by cryosurgery once a week during the second irradiation method followed by sinus curetting at the end of initial treatment. Histologically confirmed recurrence was removed by maxillectomy, if possible. The three year cumulative survival rates in the four groups were 27.1% (first group), 55.1% (second group), 53.5% (third group) and 53.1% (fourth group). The three year local non-recurrence rates after initial treatment without maxillectomy were 26.4%, 31.1%, 55.8% and 45.4%, respectively. The frequency of distant metastasis without local recurrence was as high as 12.3% in the third group and conversely 5.6% in the fourth. These results demonstrated the usefulness of cryosurgery.

Cryosurgery↗
PubMed1982

Reactivated response of blink reflex in the cat.

Three reflex responses in the orbicularis oculi muscles were observed by electrical stimulation of the trigeminal nerve in lightly anesthetized or conscious cats. The third response, following the first and second responses, was concluded as being a "reactivated response" of the blink reflex as it was set up by the trigeminal afferent input evoked by the palpebral movement of the preceding blink. The reasons for this were as follows: 1) the third response disappeared on administration of muscle relaxants and 2) was enhanced by touching the palpebral hair; 3) the palpebral movement activated the afferent discharges of the trigeminal exteroceptors which were strong enough to yield the reflex responses and 4) the latency of the first reflex response by the palpebral movement corresponded to the time lag between the preceding large reflex response and the third response; 5) the third response was hardly suppressed at all until the first response disappeared over a period of maximum reflex suppression following the conditioned stimulation of the trigeminal nerve.

Action Potentials↗
PubMed1981

Neutron activation analysis of nickel purified by floating zone-refining and anion exchange.

Nondestructive neutron activation analysis was performed on the nickel purified by floating zone-refining and anion exchange. It is found that floating zone-refining in vacuum is effective to remove Na, Sc, Cr, Zn, As, Ag, Sb and Hg through vaporization in addition to elimination of Se, Sb, Ta, Sm and Tb through segregation. Anion exchange method is also effective to separate Fe, Co, Zn, Mo, Hg, Th and U usually contained in the commercial nickel sources. It is concluded that combination of these two purification methods is required to obtain high purity nickel, since floating zone-refining is known ineffective to eliminate Fe and Co, main impurities in commercial nickel sources.

Activation Analysis↗
PubMed1979

Study on trace impurity elements in highly purified iron and aluminum by neutron activation analysis.

Activation analysis was carried out on the purified iron and aluminum to study the behavior of trace impurities on purification process, and to estimate the purity of the purified samples. Thermal neutrons with high Cd ratio through D2O column or graphite column were used for the activation of samples to reduce the interference effects by fast neutrons, the reactions, (n, p) or (n, a), from matrix elements. On the zone refined aluminum, the segregation of impurity elements was cleary observed. In the case of iron, decrease of impurity content was confirmed on superposing the various purification processes.

Aluminum↗
PubMed1979

[Clinico-antimicrobial evaluation of cefuroxime by observation of transitional change of micro-organisms in urine specimen (author's transl)].

Cefuroxime (CXM) was administered for 1 week to spinal cord injury patients with chronic complicated urinary tract infection and the transitional change of micro-organisms was observed. Bacterial counts and identification of isolated organisms were performed daily on the mid-stream urine for 1 week. MIC was also determined on the strains before and after CXM treatment. The results with 83 strains from 28 patients are as follows: 1. CXM's efficacy appears in line with MIC of strains. With the cases given 0.75 g twice daily intramuscularly, all the 14 strains with MIC lower than 50 micrograms/ml were eradicated, but 2 of the 14 strains were found re-growing, with only bacteriostatic action noted (in region of minimal inhibitory action). With the group of the cases given 1.5 g twice daily, all the 15 strains with MIC lower than 200 micrograms/ml were eradicated from urine 1 approximately 3 days after start of treatment (in region of bactericidal action). 2. At dose of bactericidal action CXM responded effectively with no relationship to organism species or bacterial count before CXM treatment. 3. Dose response was noted between the cases given 1.5 g daily and those given 3.0 g daily. 4. From the above result, we can presume appropriate doses in accordance with the disease conditions. From above observation, combined with correlation between organism species, bacterial count, MIC of strains, etc., CXM's efficacy was assessed quantitatively and objectively.

Bacteria↗