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Biomedical subjects

Seiji Katayama

Publications and source records attributed to Seiji Katayama.

6 recordsLinked to original sources
PubMed2006

Postoperative adjuvant treatment for pineal parenchymal tumour of intermediate differentiation.

Pineal parenchymal tumour of intermediate differentiation (PPTID) in adults is rare and a treatment strategy for this condition has not yet been established. We present a case of an elderly patient treated with postoperative adjuvant therapy using radio- and chemotherapy. This 60-year-old man presented with a 3-month history of memory disturbance, gait instability and double vision. Computed tomography and magnetic resonance imaging demonstrated a mass in the pineal region that suggested a malignant tumour. Partial removal of the tumour was undertaken via the right occipital transtentorial approach. The histological diagnosis was PPTID. Postoperative radio- and chemotherapy were administered, with a good response. Little is known about the clinical behaviour of PPTID in adults. Our treatment plan indicates one effective option for the management of such tumours.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2006

Tricyclic quinoxalinediones, aza-kynurenic acids, and indole-2-carboxylic acids as in vivo active NMDA-glycine antagonists.

This review article describes the development of in vivo active antagonists for the glycine binding site of the N-Methyl-D-Aspartate (NMDA) receptor. There were several difficulties in identifying a class of antagonists with in vivo efficacy and only a few compounds succeeded in emerging with activity in vivo. A series of tricyclic quinoxalinediones was highly potent glycine antagonists in vitro and the derivatives having a zwitterionic moiety including SM-18400 indeed showed in vivo activity. Similarly, tricyclic indole-2-carboxylic acids having a zwitterionic moiety such as SM-31900 were also active in vivo. In fact, SM-18400 and SM-31900 exhibited efficacy in several animal stroke models using intravenous infusion protocols. The practical syntheses of SM-18400 and SM-31900 as well as the novel synthesis of moderately active glycine antagonists, tricyclic azakynurenic acids, were also developed.

Carboxylic Acids↗
PubMed2005

[A deficit in preattentive processing of visual information in schizophrenic patients].

Schizophrenia is associated with deficits in information processing. Several studies have shown impairments in attentional functions of visual perception in schizophrenic patients. Attentional function is thought to consist of two stages; preattentive processing and attentive processing. Preattentive processing enables an individual to detect a target without scanning stimuli one by one. The search time is almost constant as distoractors increase. On the other hand, attentive processing needs sequential scanning of stimuli to detect a target. Here, the search time increases as distractors increase. In this paper, preattentive information processing was investigated in 30 schizophrenic patients and 30 control subjects using visual search tasks. Subjects were instructed to find a target and press a button in two kinds of visual search tasks. The figures of tasks were constructed with one 'L' and 5, 17, 35 'X's in the high-pop-out task, and one 'L' and 5, 17, 35 'T's in the low-pop-out task. The performance of the high-pop-out task requires preattentive processing. The time to push the button, the time for the viewpoint to reach the target and the direction of the first saccade were recorded using the eye-mark recorder. The reaction time to push the button in schizophrenics was generally longer than that in controls, irrespective of the levels of pop-out. In addition, the time for the viewpoint to reach the target was also greater in schizophrenics. Also, in the direction of the first saccade, schizophrenics showed a lower rate of making the first saccade toward the target than controls in the high-pop-out task. In conclusion, the present results suggests that there is some kind of deficit in preattentive processing of visual information in schizophrenic patients.

Attention↗
PubMed2003

Tricyclic indole-2-carboxylic acids: highly in vivo active and selective antagonists for the glycine binding site of the NMDA receptor.

A series of tricyclic indole-2-carboxylic acid derivatives were synthesized and evaluated by the radioligand binding assay and the anticonvulsant effects in the mouse NMDA-induced seizure model. Among them, derivatives of 3S-(-)-4 such as 3a, 3f, and 3g which had certain zwitterionic anilides showed high affinity to the NMDA-glycine binding site. The absolute configuration of 3S-(-)-4 was confirmed by X-ray crystallographic analysis. In particular, 3g (SM-31900) was found to be a highly active glycine antagonist for both in vitro and in vivo assays (K(i) = 1.0 +/- 0.1 nM, ED(50) = 2.3 mg/kg, iv) and also showed high selectivity for the glycine site. In addition, 3g was soluble enough in aqueous media (>10 mg/mL at pH 7.4) to use for medications by intravenous injection.

Animals↗
PubMed2002

Relationships between serum magnesium levels and clinical background factors in patients with mood disorders.

We measured serum magnesium (Mg) levels in 71 in-patients and out-patients with mood disorders and in 30 healthy controls and investigated the relationships between serum Mg levels and clinical background factors. Serum Mg levels were found to be significantly higher in patients with mood disorders than in controls. Serum Mg levels showed no significant correlation with patient sex, age, diagnosed subtype and disease phase in the mood disorder group. Serum Mg levels in patients with major depressive disorder who were taking psychotropic drugs were not significantly different from levels seen in patients with major depressive disorder who were not taking psychotropic drugs. These results suggest that the high serum Mg levels noted in patients with mood disorder are related to the underlying disorder itself and are not influenced by clinical background factors.

Adult↗