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Biomedical subjects

T Yokota

Publications and source records attributed to T Yokota.

At least 91 records · Page 5Linked to original sources
PubMed2000

Cloning and expression pattern of a Xenopus pronephros-specific gene, XSMP-30.

The first step in kidney development is the formation of the pronephros which is derived from mesoderm. Xenopus is an appropriate model to study this process since the pronephros can be efficiently induced in animal cap explants by treatment with activin and retinoic acid (RA). Using this in vitro system, we isolated a Xenopus homologue of SMP-30 (Senescence marker protein-30), which is a Ca(2+)-binding protein that is highly conserved in vertebrates. This gene, termed XSMP-30, was found to be selectively expressed in pronephric tubules from the late tadpole stage, by whole mount in situ hybridization. Furthermore XSMP-30 was expressed in animal caps treated with both activin and RA, a condition in which the pronephros is formed in vitro. These data indicate that XSMP-30 is a specific marker for the pronephros.

Activins↗
PubMed2000

Comparison of skin prick test with serially diluted wild-type and genetically engineered recombinant Der f2.

BACKGROUND: C8/119S, a genetically engineered less allergenic mutant of group II allergen (Der f2) of house dust mite, Dermatophagoidesfarinae, was constructed in order to reduce the risk of anaphylactic reactions of allergen specific immunotherapy. OBJECTIVE: To further evaluate, with a larger number of mite-allergic patients, the safety of C8/119S for the treatments of humans. METHOD: We tested the dose-dependent responses of 20 mite-allergic volunteers to a skin prick test with C8/119S and wild-type recombinant Der f2 and compared the biologic potentials of these allergens to induce type I allergic reactions. In a separate experiment, we compared IgE binding capacities to C8/119S and to wild-type recombinant Der f2 in individual sera from 34 mite-allergic donors. RESULTS: The concentration of C8/119S needed to induce positive skin prick test (SPT) reaction was at least 100 times more than that of recombinant Der f2 in 95% of the volunteers tested. Consistent with this result, IgE binding data showed that 85% of the mite-allergic donors had little or no detectable IgE bound to C8/119S. Our data also shows that a minority of mite-allergic patients responded in a similar manner to both C8/119S and wild-type recombinant Der f2. CONCLUSION: Our data confirms that C8/119S is much less allergenic and thus can be used safely for immunotherapy of most of mite-allergic patients. Care should still be taken because, in a minority of patients, C8/119S may cause similar type I allergic reactions as does wild-type recombinant Der f2.

Adult↗
PubMed2000

Limitin: An interferon-like cytokine that preferentially influences B-lymphocyte precursors.

We have identified an interferon-like cytokine, limitin, on the basis of its ability to arrest the growth of or kill lympho-hematopoietic cells. Limitin strongly inhibited B lymphopoiesis in vitro and in vivo but had little influence on either myelopoiesis or erythropoiesis. Because limitin uses the interferon alpha/beta receptors and induces interferon regulatory factor-1, it may represent a previously unknown type I interferon prototype. However, preferential B-lineage growth inhibition and activation of Janus kinase 2 in a myelomonocytic leukemia line have not been described for previously known interferons.

Amino Acid Sequence↗
PubMed2000

Brassinolide and [26, 28-2H6]brassinolide are differently demethylated by loss of C-26 and C-28, respectively, in Marchantia polymorpha.

Metabolism of brassinolide in Marchantia polymorpha was investigated by use of in vivo suspension cultured cells. GC-MS analysis of metabolites derived from non-labelled brassinolide and [26, 28-2H6] brassinolide revealed that brassinolide was converted to 26-norbrassinolide while [26, 28-2H6]brassinolide to [26-2H3]28-norbrassinolide. It seems that Marchantia cells recognized [26, 28-2H6]brassinolide as a xenobiotic rather than brassinolide and deteriums attached to C-28 significantly affect demethylation reaction due to isotopic effect. Thus, demethylation of brassinolide in planta seems to proceed by loss of C-26 rather than C-28. The present finding is the first evidence for demethylation metabolism of brassinosteroids. The biological activity of 26-norbrassinolide was 10-fold reduced as shown by the rice lamina inclination test. However, because of its high biological activity, it remains difficult to conclude whether or not C-26 demethylation serves as an important deactivation process of brassinolide.

Brassinosteroids↗
PubMed2000

The striking effect of hyperbaric oxygenation therapy in the management of chronic idiopathic intestinal pseudo-obstruction.

Chronic idiopathic intestinal pseudo-obstruction is one of the disorders that is most refractory to medical and surgical treatment. Even when patients are given nutritional support, including total parenteral nutrition, obstructive symptoms seldom disappear. We report a case of chronic idiopathic intestinal pseudo-obstruction, due to myopathy, in which hyperbaric oxygenation therapy was strikingly effective. The presence of myopathy was histologically confirmed on the surgically resected jejunal specimen. Hyperbaric oxygenation resulted not only in relief of the patient's obstructive symptoms but also in a rapid decrease of abnormally accumulated intestinal gas. At last, he could resume oral intake without any critical adverse effects. These observations strongly suggest that hyperbaric oxygenation can be an effective therapy in the management of chronic idiopathic intestinal pseudo-obstruction.

Chronic Disease↗
PubMed2000

Detection of peptidoglycan in human plasma using the silkworm larvae plasma test.

Silkworm larvae plasma (SLP) reagent, which is prepared from the body fluid of the silkworm, reacts with peptidoglycan (PG), a fragment of both the Gram-positive and Gram-negative bacterial cell wall, as well as with beta-glucan, a component of fungi. We developed a quantitative method for the detection of PG in human plasma from cases with bacterial infection using the SLP reagent. Tested in this way, the SLP method showed 86.2% sensitivity, 90.6% specificity, 89.3% positive predictive value, and 88.5% efficiency. The SLP method provides a valuable tool for the diagnosis of systemic infection using patients' blood.

Animals↗
PubMed2000

Postmortem study of ataxia with retinitis pigmentosa by mutation of the alpha-tocopherol transfer protein gene.

A new syndrome of ataxia and retinitis pigmentosa with vitamin E deficiency caused by the missense mutation of alpha-tocopherol transfer protein (alpha-TTP) gene was recently proposed. After studying the first postmortem case with this mutation pathologically and biochemically, whether the symptoms can be treated by supplementation of vitamin E or not is discussed. The major pathological findings were retinal atrophy; severe dying back-type degeneration of the posterior column; and massive accumulation of lipofuscin in neurons including dorsal root ganglion (DRG) cells, which were almost identical to those in vitamin E deficient animals and patients with fat malabsorption. Also, mild loss of Purkinje cells was noted. Because robust expression of alpha-TTP was detected in the cerebellum as well as in the liver and the tissue concentration of vitamin E in the cerebellum was still low even after oral supplementation, the mild Purkinje cell loss might be related to the mutant alpha-TTP in the cerebellum. By contrast, in the DRG, thought to be mainly responsible for ataxia, no expression of alpha-TTP was detected, and the tissue concentration of vitamin E increased to normal after supplementation. It is therefore considered that oral supplementation of vitamin E should effectively counteract the progression of ataxia.

Aged↗
PubMed2000

Production of enzymatically and immunologically active Der f 1 in Escherichia coli.

Der f 1 is a major house dust mite allergen belonging to the cysteine protease family. Because of the great demand for clinical and research use of this allergen, much effort to establish an efficient method of preparing purified Der f 1 has been made. We constructed an isopropyl-beta-D-thiogalactopyranoside-inducible expression plasmid to produce the pro-form of Der f 1 in Escherichia coli. The recombinant product was accumulated as insoluble inclusion bodies in cells. The solubilized inclusion bodies were found to be successfully renatured by two-step gel filtration chromatography. About 70 mg of pro Der f 1 were properly refolded by this method from 1 liter of culture. Acid treatment of the renatured pro Der f 1 resulted in the autocatalytic removal of the pro-sequence. The obtained mature form of Der f 1 bound IgE in patient sera and induced the release of histamine from peripheral blood leukocytes equally to native Der f 1. Furthermore, mature Der f 1 obtained by this method had identical protease activity with native Der f 1. We also discussed the contribution of the pro-sequence and the sugar chain of Der f 1 to its antigenic and enzymatic activity. This is the first report to produce an active mature form of recombinant Der f 1 in E. coli.

Allergens↗
PubMed2000

Production of humanized Fab fragment against human high affinity IgE receptor in Pichia pastoris.

Binding of allergen-IgE complexes to the high affinity IgE receptor (Fc epsilonRI) on mast cells and basophils leads to the release of various mediaters such as histamine. Fab fragments prepared by the papain digestion of humanized antibody against human Fc epsilonRI inhibited the release of histamine from human basophils. Here we established an expression system to directly produce Fab fragments of the humanized anti-human Fc epsilonRI antibody in methylotropic yeast, P. pastoris. Fab fragments were efficiently secreted into the medium at a concentration of 10-40 mg/L using a signal sequence from the P. pastoris phosphatase gene. They were consisted of disulfide-linked light and heavy chains correctly starting from the first amino acid residues by proper cleavage of the signal peptides. The obtained Fab fragments inhibited the binding between IgE and Fc epsilonRI as efficiently as the counterpart prepared by papain digestion of the whole antibody.

Amino Acid Sequence↗
PubMed2000

Splice isoforms of transcription factor Elf-1 affecting its regulatory function in transcription-molecular cloning of rat Elf-1.

To elucidate the role of Elf-1 in Fc epsilonRI alpha chain expression, rat Elf-1 cDNAs were isolated and characterized. The rat Elf-1 cDNA of 2744 bp contained an open reading frame of 1848 bp. In addition to the full length rat Elf-1 cDNA (named type 1), two splice isoforms were isolated. One of the two isoforms lacked the amino acid residues from 85th to 120th (type 2), and the other from 85th to 175th (type 3). Similar isoforms were also observed in human tissue. Overexpression of rat Elf-1 (type 1) using a transient coexpression system inhibited of the alpha chain promoter activity. The inhibition activity was different between the isoforms; the inhibition activity of type 2 was lower than that of type 1, and type 3 did not have an inhibitory effect. This observation suggested that each Elf-1 isoform played a different role in the gene expression under its control.

Amino Acid Sequence↗
PubMed2000

Analysis of catalytic residues of Thermoactinomyces vulgaris R-47 alpha-amylase II (TVA II) by site-directed mutagenesis.

To confirm that the catalytic residues (Asp325, Glu354, and Asp421) are necessary for the hydrolysis of starch, pullulan, and cyclodextrins, we constructed TVA II mutated by site-directed mutagenesis. The mutated enzymes (D325N, E354Q, and D421N) had markedly reduced levels of activity, less than 0.006% of the wild type, indicating that these three residues are the catalytic sites for these substrates. Even E354D had reduced levels of activity, less than 0.05% of wild type. These four mutated enzymes retained a trace of activity. From the result of hydrolysis patterns for maltohexaose, in particular, D421N, unlike D325N and E354Q, catalyzed transglycosylation rather than hydrolysis. The results suggest that Asp421 could function to capture water molecules.

Catalytic Domain↗
PubMed2000

Lysyl-tRNA synthetase of Bacillus stearothermophilus molecular cloning and expression of the gene.

The gene of the lysyl-tRNA synthetase of Bacillus stearothermophilus NCA1503 was cloned and sequenced. The gene consists of 1485 bp nucleotides commencing with an ATG start codon and ending with a TAA stop codon, and encodes a polypeptide of 493 amino acids. The recombinant enzymes were expressed in E. coli using an expression plasmid containing the T7 RNA polymerase/promoter.

Amino Acid Sequence↗
PubMed2000

Lymph-node staining with activated carbon CH40: a new method for axillary lymph-node dissection in breast cancer.

OBJECTIVE: To demonstrate the usefulness of activated carbon particles (CH40) as a vital staining dye for visualizing lymphatic vessels and lymph nodes in breast cancer. DESIGN: A retrospective evaluation. SETTING: Department of Surgery in Sendai National Hospital, Japan, a 716-bed teaching hospital. METHODS: To identify as many lymph nodes as possible in the axillary fat, by which we might decrease the possibility of the presence of undetected metastatic nodes, an emulsion of activated carbon particles (CH40) was injected into the centre of the mammary gland, close to the tumour site, 3 days before radical surgery. MAIN OUTCOME MEASURE: The number of lymph nodes found by the traditional method and by the CH40-injection method were recorded. RESULTS: After injection, the CH40 was readily adsorbed into regional lymphatics and streamed along with the lymph flow to blacken regional lymph nodes. The CH40-guided method increased the mean number of nodes per case found in the axilla from 8.4, by the traditional method, to 14.0 nodes per case. CONCLUSIONS: The use of the CH40 technique has two technical advantages; one is that it allows surgeons to locate the blackened lymph nodes at the time of surgery and the other is that it allows pathologists to look for the nodes in fatty tissue. Lymph-node dissection with the aid of activated carbon particles is inexpensive, easy to perform and enables the smallest lymph nodes to be easily recognized. CH40 is the technique of choice for the detection of axillary lymph nodes in cases where the number of lymph nodes detected by the traditional method is too small for accurate surgery. In conclusion, the present study demonstrates that CH40 could be an appropriate tool for more accurate staging of breast cancer axillary specimens.

Adult↗
PubMed2000

[Radiation-induced squamous cell carcinoma of the chest wall seven years after adjuvant radiotherapy following the surgery of breast cancer: a case report].

A 54-year-old woman, who had underwent an adjuvant radiotherapy following the modified radical mastectomy in the left primary breast cancer in June 1988. She underwent second surgery and adjuvant radiotherapy (electronic radiotherapy) for recurrent breast cancer in the major pectoral muscle and received chemoimmunotherapy in May 1989. In May 1996 she complained of two ulcers of the chest wall. The ulcer biopsy findings was squamous cell carcinoma, and we diagnosed she fell the radiation-induced skin cancer. She underwent chest wall resection and reconstruction with vertical rectal abdominal musculocutaneous flap (VRAM). However two months later her chest wall resection, she again got the recurrent squamous cell carcinoma in the right axillary lymph nodes and left pleura. The third radiotherapy and the chemotherapy with pepleomycin were uneffective on her recurrent cancer. And she died in March 1997.

Breast Neoplasms↗
PubMed2000

Clinicopathologic prognostic factors in patients with Borrmann type 4 gastric cancer: univariate and multivariate analyses.

BACKGROUND: Advanced gastric cancer is classified into four Borrmann types, types 1 to 4. Type 4 is a relatively undifferentiated carcinoma with little or no gland-forming capability. Despite recent advances in the diagnosis and surgical management of gastric cancer, most tumors of Borrmann type 4 are not detected at an early stage and the prognosis remains poor; the five-year survival rate after gastric resection ranges from 10 to 20 percent. We evaluated the affects of several clinicopathologic variables on the 5-year survival rate after resection of Borrmann type 4 gastric cancer. METHODS: Data on clinical characteristics were obtained from the records of patients who underwent gastric resection between 1985 and 1995 at the Department of Surgery, Sendai National Hospital, and follow-up data were obtained from our tumor registry. Pathologic characteristics were determined from a detailed review of all available histopathologic slides. The relationship between clinicopathologic variables and 5-year survival rate was estimated by the Kaplan-Meier survival curve and the logrank test. Multivariate Cox's proportional hazards regression analysis was then performed to determine which variables were independent prognostic factors. RESULTS: Eighty-seven patients with Borrmann type 4 gastric cancer underwent a resection during the study period at our hospital. The overall 5-year survival rate was 14.8%. The relationship between clinicopathologic variables and 5-year survival rate was determined by constructing a Kaplan-Meier survival curve. Tumor location (upper, middle and distal vs whole stomach, p=0.0214), lymph node metastasis, capillary microinvasion, and peritonitis carcinomatosa (absent vs present, p<0.05) significantly influenced survival. When multivariate analysis using Cox's proportional hazards regression of 5-year survival was performed, capillary microinvasion, peritonitis carcinomatosa (absent vs present) and tumor location (distal vs whole stomach) emerged as the statistically significant independent prognostic factors associated with long-term survival. CONCLUSION: Capillary microinvasion and the presence or absence of peritonitis carcinomatosa are more powerful predictors of 5-year survival than is lymph node metastasis. Patients with gastric cancer of the whole stomach have a poorer prognosis than do those with carcinoma in the antrum of the stomach.

Adult↗