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Biomedical subjects

Y Takeuchi

Publications and source records attributed to Y Takeuchi.

At least 1,009 records · Page 56Linked to original sources
PubMed1983

Immunohistochemical observation of serotonin neurons in newborn mouse and rat brainstem cultures.

Serotonin neurons in newborn mouse and rat brainstem cultures were studied by peroxidase-antiperoxidase immunohistochemistry using a serotonin antibody. The intensity of the immunohistochemical reaction in the neuronal somata decreased gradually with time and was hardly detectable after one month of culturing. On the other hand, the immunoreactivity of the processes noted at the early stages later on became more intense and covered the full extent of the fibers. From the early stages of the cultures, the axon of each serotonin neuron formed not only a network by branching, but also a true anastomosis with the axonal networks of the other serotonin neurons.

Animals↗
PubMed1983

New broad-spectrum cephalosporins with anti-pseudomonal activity. II. Synthesis and antibacterial activity of 7 beta-[2-acylamino-2-(4-hydroxyphenyl)acetamido]-3-[ (1-methyl-1H-tetrazol-5-yl)thiomethyl]ceph-3-em-4-carboxylic acids.

The influence of the chirality of the 7-acyl side chain and of various N-acyl moieties (A-CO-) on the in vitro activity of 7 beta-[2-acylamino-2-(4-hydroxyphenyl)acetamido ]-3-[(1-methyl-1H-tetrazol-5-yl)thiomethyl]ceph-3-em-4-carboxylic acids (6) was investigated. A cephalosporin having a 7-acyl side chain of S-configuration (6r) was only weakly active against Staphylococcus aureus and Klebsiella pneumoniae and was inactive against the other species tested. Among the various N-acyl moieties in the cephalosporins having a 7-acyl side chain of the R-configuration, the 4-hydroxypyridine-3-carbonyl moiety, unsubstituted or substituted with 5-bromo and/or 6-alkyl groups and the 4-hydroxy-1,5-naphthyridine-3-carbonyl moiety, unsubstituted or substituted with a 6-methyl and a 6-methoxy group gave the most active compounds. N-Ethylation of the 4-hydroxy-1,5-naphthyridine-3-carbonyl derivative and the 4-hydroxypyridine-3-carbonyl derivative (6p, 6q) resulted in a decrease of the in vitro activity.

Bacteria↗
PubMed1983

Effect of beta-receptor blockade on the development of resistance to trauma in rats.

To study the mechanisms of the development of resistance to trauma, we examined the survival of a tumbling trauma using a Noble-Collip drum (40 rpm) by rats conditioned by sublethal drummings with and without prior administration of propranolol. The drum conditioning that consisted of four consecutive sublethal drummings (200, 350, 500, and 650 revolutions) induced increased resistance to an otherwise lethal drumming (800 revolutions) in rats without pretreatment of propranolol. Rats administered with propranolol 4 mg/kg intraperitoneally (ip) prior to each sublethal drumming showed a mortality of 22% after the lethal drumming which was significantly less than the mortality of 92% in nonconditioned rats pretreated with propranolol. This increased resistance to a lethal trauma in rats conditioned by drummings with concurrent administration of propranolol was confirmed in another lot of rats. These results indicated that prior administration of propranolol 4 mg/kg ip did not inhibit the induction of trauma resistance by repeated sublethal drummings, suggesting the existence of a mechanism unaffected by this dose of propranolol.

Adaptation, Physiological↗
PubMed1983

Distribution of serotonergic neurons in the central nervous system: a peroxidase-antiperoxidase study with anti-serotonin antibodies.

Distribution of serotonin (5-HT) neurons in the central nervous system (CNS) of various vertebrates was investigated with a highly sensitive immunohistochemical technique. Antibodies were raised in rabbits against an antigen prepared by coupling 5-HT to bovine thyroglobulin. 5-HT neurons were found to be distributed more widely and densely than has been heretofore described. Serotonergic neuronal somata are organized according to certain basic patterns, but there are interspecific differences with regard to the distribution of 5-HT fibers. The processes of 5-HT neurons form a dense plexus by ramification and anastomosis in almost all areas of the CNS, including the ventricular surfaces. In the light of our observation, Golgi's reticular theory may have to be revised.

Animals↗
PubMed1983

[Intra-arterial infusion through 2 routes in liver (primary and metastatic cancer].

Patients with unresectable liver cancer (primary and metastatic) were treated with a newly-devised arterial infusion chemotherapy using Cis-DDP and its antidote Sodium thiosulfate (STS). The patients consisted of 4 with primary hepatoma and 1 with metastatic liver cancer originated from intestinal cancer. For the purpose of reducing unfavourable side effects without changing anticancer effect, Cis-DDP was infused into hepatic artery through the catheter while STS being administered systemically. According to Koyama and Saito's criteria, 2 of 5 patients showed partial response (PR) and the others showed no change (NC). The median survival time after onset of therapy was 6.6 months ranging from 2 to 11 months in all the patients. The myelosuppression and renal toxicity, which were considered to be the most serious side effects of Cis-DDP, were not found and liver function was not affected in all the patients. However, all the patients complained of nausea and vomiting. Thus, our experience has indicated that this newly devised infusion chemotherapy is a promising method for treating unresectable liver cancer, although further efforts are necessary for reducing the gastrointestinal toxicity.

Adult↗
PubMed1982

Absorption spectral properties of acetylated bacteriorhodopsin in purple membrane depending on pH.

The dark-adapted form of bacteriorhodopsin in the purple membrane of Halobacterium halobium changes its absorption maximum from 560 to 600 nm if the pH is lowered to about 2 [Oesterhelt, D., & Stoeckenius, W. (1971) Nature (London), New Biol. 233, 149; Moore, T. A., Edgerton, M. E., Parr, G., Greenwood, C., & Perham, R. N. (1978) Biochem. J. 171, 469; Mowery, P. C., Lozier, R. H., Chae, Q., Tseng, T.-W., Taylor, M., & Stoeckenius, W. (1979) Biochemistry 18, 4100; Fischer, U., & Oesterhelt, D. (1979) Biophys. J. 28, 211; Muccio, D. D., & Cassim, J. Y. (1979) J. Mol. Biol. 135, 595]. We compared the pH dependence of the absorption spectra of acetylated membrane with that of unacetylated native membrane. The completely acetylated membrane showed a midpoint of pH 4.8 for the conversion to the acidic form; that of the native membrane was 3.4. On acetylation, the absorption maximum at neutral pH moved from 560 to 555 nm with about 20% decreases in extinction coefficients as compared with that of the native membrane, whereas the spectrum in acid was not affected. The chloride-dependent blue shift from the acidic form of the acetylated membrane was largely suppressed. The CD spectrum of the acetylated membrane was composed of two bands of an opposite sign with slightly decreased amplitudes. The chromophore of the acetylated membrane was sensitive to hydroxylamine, and the spectrum before bleaching was restored on addition of all-trans-retinal to the bleached membrane followed by dark incubation. Blue light irradiation accelerated the conversion to the acidic form in the native membrane but not in the acetylated membrane. Reductive ethylation did not affect the pH dependence of the absorption spectra.

Acetylation↗
PubMed1982

Reciprocal connections between the amygdala and parabrachial nuclei: ultrastructural demonstration by degeneration and axonal transport of horseradish peroxidase in the cat.

An ultrastructural analysis of the connections of the amygdala with the parabrachial nuclei (PBN) was carried out after electrolytic lesions or injections of horseradish peroxidase in the amygdala. Degenerating and labeled terminals originating from the amygdala formed axosomatic and axodendritic synapses in the PBN. In some instances, anterogradely labeled terminals synapsed with retrogradely labeled neurons. These results demonstrate that the amygdala and PBN have close reciprocal synaptic connections.

Amygdala↗
PubMed1982

Immunohistochemical study on the distribution of serotonin fibers in the spinal cord of the dog.

Distribution of serotonin fibers in the spinal cord of the dog was investigated by means of a modified PAP method; a rabbit anti-serotonin serum prepared in the laboratory of the authors was used in this study. Serotonin fibers were revealed as PAP-positive dark-brown elements displaying dot-like varicosities (0.5--2.0 micrometers in diameter). In the spinal cord of the dog, the distribution of serotonin fibers is extensive. These fibers occur more densely in more caudal segments and are most prominent at the sacrococcygeal level. From the level of the cervical spinal cord to the upper lumbar region, the descending serotonin fibers are located immediately under the pia mater in the ventrolateral portion of the lateral funiculus. In more caudal segments, serotonin fibers are dispersed throughout the ventral and lateral funiculi. These longitudinal en passage-fibers send numerous transverse collaterals to the gray matter. Serotonin fibers are distributed abundantly in the laminae I and III of the posterior column, while only a few fibers are found in the lamina II (substantia gelatinosa). In the intermediate zone, two descending serotonin pathways, i.e., lateral and medial longitudinal bundles, are observed to coincide topographically with the nucleus intermediolateralis at C8(T1)--L3(L4) and the nucleus intermediomedialis at C1--Co respectively. The former is particularly prominent and communicates with the contralateral bundle via commissural bundles at intervals of 300--500 micrometers. The large motoneurons in the anterior column, especially those in the nucleus myorabdoticus lateralis within the cervical and lumbar enlargements, are closely surrounded by fine networks of serotonin fibers and terminals.

Animals↗
PubMed1982

Immunohistochemical demonstration of the distribution of serotonin neurons in the brainstem of the rat and cat.

The morphological characteristics and distribution of the somata of serotonin-containing neurons in the brainstem of rats and cats were studied by use of the peroxidase-anti peroxidase (PAP) immunohistochemical method employing highly specific antibodies to serotonin. Antibodies were raised in rabbits against an antigen prepared by coupling serotonin to bovine thyroglobulin and using formaldehyde as the coupling reagent. The distribution pattern of serotonin neurons observed in the present material is essentially in agreement with that described by other investigators who used the Falck-Hillarp method. In addition, this immunohistochemical technique revealed serotonin-containing perikarya in the following regions: 1) the periaqueductal gray, especially lateral to the nucleus raphe dorsalis, 2) the nucleus interpeduncularis, 3) the nucleus parabrachialis ventralis and dorsalis, 4) the field of the lemniscus lateralis, and 5) the reticular formation of the pons and medulla oblongata. The described immunohistochemical procedure makes it possible to study central serotonin neurons in detail without pharmacological pretreatment. The wide distribution of serotonin neurons demonstrated in this study should be considered when interpreting experiments dealing with the serotonin system.

Animals↗