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Biomedical subjects

I Kumazawa

Publications and source records attributed to I Kumazawa.

9 recordsLinked to original sources
PubMed2001

Linear constraints on weight representation for generalized learning of multilayer networks.

In this article, we present a technique to improve the generalization ability of multilayer neural networks. The proposed method introduces linear constraints on weight representation based on the invariance natures of training targets. We propose a learning method that introduces effective linear constraints into an error function as a penalty term. Furthermore, introduction of such constraints leads to reduction of the VC dimension of neural networks. We show bounds on the VC dimension of the neural networks with such constraints. Finally, we demonstrate the effectiveness of the proposed method by some experiments.

Algorithms↗
PubMed1999

[A recurrent case of esophageal cancer in which metastatic skin tumor disappeared after local injection of activated lymphocytes with tumor-pulsed dendritic cells].

We examined the effect of activated lymphocytes stimulated with tumor-pulsed dendritic cells (DC-K), and found that such stimulation enhanced the cytotoxity of the activated lymphocytes. Furthermore, in applying DC-K to a recurrent case of esophageal cancer, the skin tumors disappeared after local injection of DC-K. The only adverse effect of this treatment was pyrexia. Although no general effect was observed, the local effect was satisfactory. This suggests that DC-K might be useful for local treatment or postoperative adjuvant therapy.

Aged↗
PubMed1998

Effect of site directed mutagenesis in the CMGCC region of the alpha-subunit on immunoreactive human thyrotropin.

The cDNA of the common alpha-subunit of human glycoprotein hormone was mutated by site directed mutagenesis in the CMGCC region composed of cysteine-methionine-glycine-cysteine-cysteine (position 28-32). The cDNA of wild-type human thyrotropin (hTSH) beta-subunit and that of wild-type or mutant common alpha-subunits were co-transfected into COS-I cells. The concentration of hTSH determined by two immunoradiometric assay systems was detectable in culture media of COS-I cells transfected with wild-type (CMGCC) and a mutant (CRGCC) alpha-subunits but not four other mutants (YMGCC) (CMRCC) (CMACC) (CMDCC). The present data with the other studies on wild-type or mutant glycoprotein hormones support our hypothesis that an amino acid motif of "C-X-G-X-C" in the common alpha-(CMGCC in human) and beta-(CAGYC in human) subunits play an important role in biosynthesis of glycoprotein hormones in all species.

Amino Acid Substitution↗
PubMed1997

The role of N-terminal glycosylation in the human oxytocin receptor.

The human oxytocin receptor includes three N-glycosylation sites in its extracellular N-terminal domain. We have established permanent cell-lines in which the gene for the human oxytocin receptor (OTR) has been introduced into HeLa cells. These cells differ by the disruption of one or more of the N-terminal N-glycosylation sites by site-directed mutagenesis of the transfected OTR constructs. The binding capacity of each transfectant, calculated per mg membrane protein, was 5-17 times higher than that of human term myometrium. The pharmacological characteristics of the transfected wild-type OTR are very similar to those of native myometrial OTR. The mutation of N-glycosylation sites (Asn-X-Ser/Thr), namely OTR-D8N15N26 (Asn8-->Asp8), -N8D15N26(Asn15-->Asp15), -N8D15D26(Asn15-->Asp15, Asn26-->Asp26) and -D8N15D26 (Asn8-->Asp8, Asn26-->Asp26) appear to affect neither their dissociation constant (Kd), nor the affinities for various oxytocin related ligands. As a high level of cell surface binding was retained for each clone, receptor trafficking appears to be normal. This suggests that the full glycosylation of OTR observed in vivo is not essential for its activity. These results indicate also that these cell lines may prove very useful for pharmacological screening of oxytocin related products.

Gene Transfer Techniques↗
PubMed1997

[Spirochetosis].

Explore the source record for details and available documents.

Humans↗
PubMed1996

Expression of oxytocin receptor in human pregnant myometrium.

Around the onset of labor, uterine sensitivity to oxytocin (OT) increases tremendously. Although this is considered to reflect OT receptor (OTR) augmentation in myometrium, neither spatial expression of OTR nor the level of the receptor message during the course of pregnancy have been investigated at the molecular level. We examined the localization and expression of the OTR in human myometrium by means of in situ hybridization, immunohistochemistry, and Northern and Western blotting. In the term pregnant myometrium, OTR expressing smooth muscle cells are observed diffusely and heterogeneously. Some of the smooth muscle cells were expressed high levels of the receptor at the messenger RNA and protein level, and they were surrounded with cells weakly positive for the OTR or negative. The level of OTR transcripts increased according to the course of pregnancy. The receptor messenger RNA level reached over 300-fold at parturition compared with the nonpregnant myometrium. In the myometrium at 32 weeks of gestation and not in labor, a relatively large amount (about 100-fold) of the receptor message was expressed. In the nonpregnant myometrium, significant amount of the receptor protein was revealed by Western blotting. We also found that the receptor protein was augmented at term and after the onset of labor. These findings indicated that the expression of OTR changes dynamically at the transcription and protein level during pregnancy and that its expression is heterogeneous in the term myometrium.

Amino Acid Sequence↗
PubMed1993

[A case of postoperative pulmonary metastasis of colon cancer which responded to treatment with leucovorin and 5-FU].

A 72-year-old man underwent a radical operation for sigmoid colon cancer (well-differentiated adenocarcinoma, stage III) in 1989. Chest X-ray examination performed in September 1992 showed multiple nodular shadows in the lungs. A diagnosis of pulmonary metastasis was made from abnormally increased CEA and CA 19-9 and findings by chest tomography and CT scanning. There was no evidence of metastasis or recurrence in the liver, bone, brain or large intestine. He received three courses of bolus injections of leucovorin (30 mg/body) and 5-FU (500 mg/body), each over five consecutive days with a two-week rest period, and subsequently weekly at the same doses. CEA and CA 19-9 levels started to decrease after completion of the second course of consecutive treatment. In week 18 of chemotherapy, CEA and CA 19-9 levels dropped to 5.6 ng/ml and 32 U/ml from 66 ng/ml and 130 U/ml, respectively. Chest tomography and chest CT showed the disappearance or reduction in size of the nodules, with a reduction rate of 87.1%. Twenty-two weeks later, at this writing, there was no evidence of disease progression, and the patient was thus judged to be PR. He continues to receive chemotherapy at our outpatient clinic.

Adenocarcinoma↗
PubMedDate not supplied

A comparison of the prognostic significance between the number of metastatic lymph nodes and nodal stage in gastric carcinoma.

BACKGROUND/AIMS: To clarify what staging system of lymph node metastasis is suitable for evaluating prognosis of gastric cancer patients. METHODOLOGY: We analyzed the survival 5 years after operation of 186 advanced gastric cancer patients who underwent potentially curative gastric resection. The following 3 systems were compared using multivariate analyses by the logistic regression model. Nodal status in pathology was classified as follows: (a) nodal stage according to the General Rules for the Gastric Cancer Study of the Japanese Research Society for Gastric Cancer (the Japanese Rules), (b) number of metastatic nodes according to the new UICC staging system (the TNM system), (c) number of metastatic nodes in n1 group of the Japanese Rules (the new classification). RESULTS: The TNM system revealed better results than the nodal stage in sensitivity and -2 log likelihood. The new classification revealed the best result among the 3 systems in sensitivity, specificity, accuracy and -2 log likelihood. CONCLUSIONS: The TNM system is a better prognostic factor than the nodal stage in the Japanese Rules, and the new classification is the best prognostic factor of the above 3 systems in potentially curative advanced gastric cancer patients. Furthermore, the new classification might be useful in comparing data between some facilities.

Adenocarcinoma↗