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Biomedical subjects

S Katoh

Publications and source records attributed to S Katoh.

At least 289 records · Page 16Linked to original sources
PubMed1989

[Endoscopic treatment of early gastric cancer in patients undergoing chronic hemodialysis].

Endoscopic treatment of early gastric cancer (type Ila in all patients) was performed in four patients undergoing chronic hemodialysis. Surgical treatment was contraindicated because of various risk factors in these patients. Endoscopic treatment was performed by concomitant use of YAG laser irradiation, local ethanol injection and mucosal resection. After endoscopic treatment, stomach biopsy revealed no cancer in four patients. In one patient who is alive now, no sign of cancer recurrence has been noted for about two years after endoscopic treatment. This patient has undergone hemodialysis on outpatient department. The remaining three patients died from diseases other than gastric cancer. When one of them was autopsied, no gastric cancer demonstrated. Taking the prognosis related to life in to consideration, endoscopic treatment should be used positively when surgical treatment of early gastric cancer cannot be performed in patients undergoing chronic hemodialysis.

Aged↗
PubMed1988

Age-related deterioration of ability of acquisition in memory and learning in senescence accelerated mouse: SAM-P/8 as an animal model of disturbances in recent memory.

Memory, learning and behavior of senescence accelerated mouse (SAM-P/8) were investigated by using passive avoidance response, T-maze and open field and the findings were compared with those from senescence resistant mouse (SAM-R/1 control). SAM-P/8 mice showed a remarkable age-related deterioration in ability of memory and learning in passive avoidance response. This age-related memory and learning deficit was linked to a deterioration in the ability of acquisition and was not due to impairment in the ability of retention and hyperactivity, as observed in the open field. In the alternation T-maze tests, SAM-P/8 showed as high a rate of alternations as did the SAM-R/1 and in the T-maze avoidance tests, SAM-P/8 also showed as intact a memory ability as seen in the SAM-R/1, despite a memory deficit in the passive avoidance response. Thus, SAM-P/8 may prove to be a pertinent model for researching mechanisms related to the memory deficit seen in senile humans.

Aging↗
PubMed1988

Suprachiasmatic nucleus neurons immunoreactive for vasoactive intestinal polypeptide have synaptic contacts with axons immunoreactive for neuropeptide Y: an immunoelectron microscopic study in the rat.

An electron microscopic study showed by using a dual immunolabeling technique that in the suprachiasmatic nucleus of the rat, axon terminals immunoreactive for neuropeptide Y (NPY) made synaptic contacts upon neurons immunoreactive for vasoactive intestinal polypeptide (VIP). Diaminobenzidine (DAB)-labeled NPY axon terminals made synaptic contacts on silver-gold-labeled VIP perikarya and dendritic processes. The presynaptic NPY terminals contained many small clear vesicles and a few cored vesicles labeled with DAB chromogen. At the synaptic portion, a symmetrical thickening of the pre- and post-synaptic membranes was evident.

Animals↗
PubMed1988

Ultrastructural localization of immunolabeled substance P and methionine-enkephalin-octapeptide in the surface layer of the dorsal horn of rat spinal cord.

A preembedding dual immunolabeling technique and electron microscopy were utilized to demonstrate the localization of immunoreactive substance P and methionine-enkephalin-octapeptide (Enk-8) in ultrathin sections of the surface layer (laminae I and II) of rat spinal dorsal horn. The immunoreaction of Enk-8 was visualized as gold-toned silver particles and that of substance P as diaminobenzidine reaction products. Axonal terminals with immunoreactive substance P, and also unlabeled axonal terminals, formed synaptic junctions with the perikarya and dendritic processes of Enk-8-containing neurons. Dendritic profiles immunolabeled for substance P were synaptically linked with unlabeled axons but not with Enk-8-positive ones. Furthermore, it was found that Enk-8 axons and substance P axons terminated synaptically in juxtaposition to one another on the same immunonegative dendrites. Among the Enk-8-containing neurons axonal profiles also appeared to be synaptically associated with immunoreactive Enk-8 dendritic processes.

Animals↗
PubMed1988

Light- and electron-microscopic evidence of costoring of immunoreactive enkephalins and substance P in dorsal horn neurons of rat.

The topographical localization of substance P (SP) and methionine-enkephalin-octapeptide (Enk-8) was examined immunohistochemically in the surface layer of the dorsal horn of rat cervical spinal cord. Although a few neurons were immunoreactive for Enk-8 in the intact animals, after an intracisternal administration of colchicine, immunoreactive Enk-8 neurons were numerous, and half of them indicated immunoreactivity also for SP. Some immunoreactive SP neurons appeared to show no immunoreactivity for Enk-8. Immuno-reactive nerve fibers, on the other hand, were numerous, and many of them contained both peptides. Electron-microscopic examination of the nerve fibers in tissue prepared by a freeze-drying procedure and stained by a postembedding procedure, revealed the costoring of both peptides in the same cored vesicles. The physiological significance of this costoring is discussed.

Animals↗
PubMed1988

Coenzyme stimulation of isomerase activity of sepiapterin reductase in the biosynthesis of tetrahydrobiopterin.

The 6-lactoyl tetrahydropterin (C1'-keto PH4) isomerase activity of sepiapterin reductase, which was found in our recent work (Katoh and Sueoka (1987) J. Biochem. 101, 275-278) as a novel activity of the enzyme, i.e., the conversion of C1'-keto PH4 to 6-1'-hydroxy-2'-oxopropyl tetrahydropterin (C2'-keto PH4) without coenzymes, could be enhanced by a small amount of NADPH or NADP+. The concentration of NADP+ required for the maximal stimulation was approximately the same as the concentration of the enzyme subunit. When NADP+ was added with the enzyme and C1'-keto PH4 at pH 8.6, the reaction sequence of C1'-keto PH4----C2'-keto PH4----tetrahydrobiopterin (BH4) was observed in the presence of dithioerythritol. These observations suggest that the coenzyme stimulating the isomerase function of sepiapterin reductase may be involved in the two sequential reductions, from pyruvoyl tetrahydropterin to BH4, by causing internal rearrangement of the keto group of the first intermediate, C1'-keto PH4, to form the second one, C2'-keto PH4.

Alcohol Oxidoreductases↗
PubMed1988

Ultrasonic evaluation of fallopian tube carcinoma.

Primary malignant neoplasms of the fallopian tube are the least common of all the gynecologic malignancies, and constitute only about 0.1-1% of all such malignancies. The actual 5-year survival is 64% in those with stage I, 60% in cases of stage II, and 18% and 25% for stages III and IV, respectively. Therefore, early detection of these neoplasm stages is most important to attain a cure. The preoperative diagnosis of this neoplasm has rarely been reported because these lesions are not common. We present herein the clinical and sonographic features in 4 Japanese women with fallopian tube carcinoma. While the sonographic features alone are not distinct enough to establish a definite preoperative diagnosis, the findings as seen in our patients suggest inclusion of tubal carcinoma in the differential diagnosis.

Carcinoma↗
PubMed1988

Differential action of nerve growth factor, cyclic AMP and neurotropin on PC12h cells.

Nerve growth factor (NGF) induced the activities of acetylcholinesterase (AChE) and Na+,K+-ATPase concomitant with neurite outgrowth in PC12h cells, while dibutyryl cyclic AMP (DBcAMP) caused the induction of AChE activity and neurite outgrowth but not Na+,K+-ATPase activity. A nonproteinaceous extract isolated from the inflamed skin of rabbits inoculated with vaccinia virus (Neurotropin) induced neurite outgrowth and cell surface change similar to NGF without affecting AChE activity. The results suggest that NGF, DBcAMP and Neurotropin act on PC12h cells through different mechanisms.

Acetylcholinesterase↗
PubMed1988

[Antigenicity test of cefodizime sodium].

The antigenicity studies of a beta-lactam antibiotic, cefodizime sodium (THR-221), were examined in mice and guinea pigs and the following results were obtained. 1) In passive cutaneous anaphylaxis (PCA) with sera from BALB/c or C3H/He mice, a slight PCA reaction was observed only in BALB/c mice by using THR-221-ovalbumin (OVA) plus Freund's complete adjuvant (FCA) as the immunogen and THR-221 itself as the eliciting antigen. 2) Immunological cross-reactivity between THR-221 and CTX was present at the rat PCA reaction. 3) Antibodies against THR-221 were detected by PCA in guinea pigs. The anti-THR-221 antibodies gave PCA responses smaller than those of CMZ by using antibiotic plus FCA as the immunogen and the antibiotic-bovine serum albumin (BSA) as the eliciting antigen. 4) In the observation of active systemic anaphylaxis (ASA), no symptoms were observed in guinea pigs sensitized with THR-221 and provoked with THR-221-BSA. On the other hand, guinea pigs sensitized with THR-221 plus FCA by injecting THR-221-BSA showed fetal anaphylactic reactions. 5) The results of passive hemagglutination (PHA) also indicated that the PHA titer of THR-221 was lower than that of CMZ. 6) Protein binding property of THR-221 with human serum albumin was lower than other beta-lactam antibiotics. 7) Antibodies against THR-221-OVA by using THR-221-BSA as the eliciting antigen were detected in any tests above mentioned. It is concluded from these results that immunological activity of THR-221 was equivalent to the other beta-lactam antibiotics.

Anaphylaxis↗
PubMed1988

[Radiation therapy of intracranial germ cell tumors].

The results of radiation therapy in 31 patients with intracranial germ cell tumors have been analyzed. The five-year survival rates were 70.1% for germinomas and 38.1% for teratomas. Three patients with germinoma have since died of spinal seeding. The prophylactic irradiation of the spinal canal has been found effective in protecting spinal seeding, since no relapse of germinoma has been observed in cases that received entire neuraxis irradiation, whereas teratomas and marker (AFP, HCG) positive tumors did not respond favorably to radiation therapy, and the cause of death in these patients has been local failure. Long-term survivors over 3 years after radiation therapy have been determined as having a good quality of life.

Adolescent↗
PubMed1988

[CT-guided stereotaxic implantation of the Ommaya reservoir for cystic brain tumors].

We report the use of CT-guided stereotaxic system to implant Ommaya reservoir in 26 patients with cystic brain tumors consisting of 16 gliomas, 3 craniopharyngiomas, 3 metastatic brain tumors and 5 other and unknown pathologies, on the way of their biopsy. The entire procedure was carried out in the CT room using Leksell's CT stereotaxic system. In 24 cases with supratentorial tumors, it was at the option of the operator to take any approach such as frontal, posterior temporal and parietal approaches. Especially in 3 cases of craniopharyngioma, we inserted the tube into their cyst directly so that the ventricle should not be open to the cyst. Also in cases of a pontine glioma and a C-P angle metastatic tumor, we used retromastoid approach to the posterior fossa by making patient's heads turned about 30 to 40 degrees to contralateral side of the approach, with slight flexion of the neck. Minimal bleeding occurred during operation in one case, however, it showed no clinical symptoms. Advantages of this method are as follows: Operative invasion is minimal; The surgeon can check the course of the cannula and position of the tip of Ommaya tube even at operation, and can modify it, if necessary.

Adolescent↗
PubMed1988

Plasma levels of dihydroxyphenylalanine, dopamine and norepinephrine in the fetoplacental unit and maternal circulation at delivery.

Dihydroxyphenylalanine (DOPA), dopamine (DA) and norepinephrine (NE) levels were measured in matched samples of maternal plasma (MV), umbilical arterial (UA) and venous (UV) blood of 25 normal infants born following an uncomplicated vaginal delivery. Levels in maternal plasma in the preterm period (36-40 weeks of gestation) and in 20 non-pregnant control subjects were also determined. DOPA and NE concentrations in the maternal vein at delivery were markedly higher than findings in the preterm period. The levels of DOPA and NE in the umbilical artery were significantly higher than those in the maternal vein at delivery. The DOPA levels in umbilical cord plasma showed arteriovenous differences indicating a net distribution of DOPA from the fetus to the mother. These data strongly suggest that the high DOPA levels in cord blood originate mainly from the fetus.

Adult↗
PubMed1987

Intragranular colocalization of arginine vasopressin and methionine-enkephalin-octapeptide in CRF-axons in the rat median eminence.

Ultrastructural appearances of axonal terminals containing corticoliberin (CRF) were examined in the rat median eminence prepared by a freeze-drying procedure. Immunolabeling was performed by using 5-, 8-, or 15-nm gold-antibody complexes for CRF, arginine vasopressin (VP) and methionine-enkephalin-octapeptide (Enk-8), singly or in combination. In intact animals, the CRF-containing secretory granules were only slightly labeled with gold-anti-VP or -Enk-8. In adrenalectomized rats, granules within single axons appeared to be labeled with all the immunogold complexes. This intragranular colocalization of the three antigens was confirmed by using three neighboring sections of the same axon terminals which were stained separately with each one of the antibodies and visualized with the avidin-biotin-peroxidase complex method. The granules labeled for CRF had decreased 9 days after adrenalectomy but had increased again by day 21, while those labeled for VP steadily increased after adrenalectomy. However, this did not correspond with the appearances of cell bodies in the paraventricular nucleus; the cell bodies labeled for both CRF and VP steadily increased in number and in stainability. By contrast, Enk-8 immunoreactivity in the axonal terminals and cell bodies was not affected by adrenalectomy. These findings suggest that although the three peptides could be released simultaneously from the axonal terminals, VP may play some special role in the expression of CRF activity.

Adrenalectomy↗
PubMed1987

Immunohistochemical evidence of serotoninergic regulation of vasoactive intestinal polypeptide (VIP) in the rat suprachiasmatic nucleus.

By applying a double-immunolabeling technique to preembedded tissue preparations, we demonstrated the existence of serotoninergic innervation to neurons containing vasoactive intestinal polypeptide (VIP) in the rat suprachiasmatic nucleus (SCN). Immunoreactivity for serotonin and VIP was revealed by the presence of diaminobenzidine (DAB) reaction products and silver-intensified DAB reaction products, respectively; in a further stage, the silver grains were substituted with gold particles. DAB reaction products were precipitated on the surface of vesicular structures, while gold particles were scattered diffusely throughout the neuroplasma at various densities. Serotoninergic axons were numerous and closely packed together, occasionally forming synaptic junctions with gold-labeled VIP-containing neurons. At these synaptic junctions, small vesicular structures accumulated to form a coat under the presynaptic membrane, and the postsynaptic membrane was lined with a homogeneous accumulation of fine deposits. This postsynaptic apparatus varied in appearance; some parts were flat and thin, while others were of irregular thickness. Serotoninergic fibers also formed synaptic junctions with unidentified neurons, in which postsynaptic membrane specialization was also observable. As VIP-containing neurons are known to be synapsed by somatostatin (SRIH)-containing neurons, their regulation must involve both serotonin and SRIH at least.

3,3'-Diaminobenzidine↗