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Biomedical subjects

H Akatsuka

Publications and source records attributed to H Akatsuka.

50 records · Page 3Linked to original sources
PubMed1994

Production of tumour necrosis factors by human T cells stimulated by a superantigen, toxic shock syndrome toxin-1.

The capacity of human T cell subsets, CD4+ or CD8+ T cells, to produce tumour necrosis factors (TNF-alpha and TNF-beta) upon stimulation with toxic shock syndrome toxin-1 (TSST-1) and the requirement for MHC class II molecules on accessory cells (AC) in the response were investigated. The capacity of CD4+ T cells was much higher than that of CD8+ T cells in TSST-1-induced production of TNF-alpha and TNF-beta. The expression of MHC class II molecules on AC was required in the response.

Animals↗
PubMed1994

The lipA gene of Serratia marcescens which encodes an extracellular lipase having no N-terminal signal peptide.

The lipA gene encoding an extracellular lipase was cloned from the wild-type strain of Serratia marcescens Sr41. Nucleotide sequencing showed a major open reading frame encoding a 64.9-kDa protein of 613 amino acid residues; the deduced amino acid sequence contains a lipase consensus sequence, GXSXG. The lipase had 66 and 56% homologies with the lipases of Pseudomonas fluorescens B52 and P. fluorescens SIK W1, respectively, but did not show any overall homology with lipases from other origins. The Escherichia coli cells carrying the S. marcescens lipA gene did not secrete the lipase into the medium. The S. marcescens lipase had no conventional N-terminal signal sequence but was also not subjected to any processing at both the N-terminal and C-terminal regions. A specific short region similar to the regions of secretory proteins having no N-terminal signal peptide was observed in the amino acid sequence. Expression of the lipA gene in S. marcescens was affected by the carbon source and the addition of Tween 80.

Amino Acid Sequence↗
PubMed1993

Preservation of the umbilical cord at the primary fascial closure in infants with gastroschisis.

Recently, the survival of patients with gastroschisis has been dramatically improved and it has reached more than 90%. Over the last 10 years, 20 of 21 cases (95%) survived in our hospital. We have been using the primary fascial closure of the abdominal wall as a standard operative procedure. The umbilical cord was usually excised at the operation in order to secure the suture line and prevent wound infection. The survivors sometimes complained of the absence of the umbilicus. However, it was somewhat difficult to create a new umbilicus later by use of the surrounding skin. In the last five cases, we tried to carry out the primary fascial closure with preservation of the umbilical cord. All patients could obtain good cosmetic results with near-normal appearance. Omphalitis or cellulitis was never observed, but a small umbilical hernia occurred in one case.

Esthetics↗
PubMed1992

Site-directed mutation makes rabbit calcyclin dimer.

Unlike human, rat and mouse calcyclin, purified rabbit calcyclin did not form a dimer on Tricine SDS-PAGE under non-reduced conditions. Based on the internal peptide sequence of rabbit calcylin, we isolated and sequenced a cDNA clone encoding calcyclin. The sequence of this clone (pCalC) is 629 bp long and codes 90 amino acid residues of a protein with a molecular mass of 10,153 Da. By Northern blot analysis, a major band of 0.9 kbp and a minor band of 2.6 kbp were detected in the lung. The recombinant calcyclin mutated serine at the third position to cysteine was expressed in E. coli and made dimer formation under non-reduced conditions on SDS-PAGE. Whether or not this type of mutation which prevents dimer formation of calcyclin plays a physiological role in the rabbit lung is the subject of an ongoing study.

Amino Acid Sequence↗
PubMed1992

Site-directed mutagenesis at aspartate and glutamate residues of xylanase from Bacillus pumilus.

To elucidate the reaction mechanism of xylanase, the identification of amino acids essential for its catalysis is of importance. Studies have indicated the possibility that the reaction mechanism of xylanase is similar to that of hen's egg lysozyme, which involves acidic amino acid residues. On the basis of this assumption, together with the three-dimensional structure of Bacillus pumilus xylanase and its amino acid sequence similarity to other xylanases of different origins, three acidic amino acids, namely Asp-21, Glu-93 and Glu-182, were selected for site-directed mutagenesis. The Asp residue was altered to either Ser or Glu, and the Glu residues to Ser or Asp. The purified mutant xylanases D21E, D21S, E93D, E93S, E182D and E182S showed single protein bands of about 26 kDa on SDS/PAGE. C.d. spectra of these mutant enzymes show no effect on the secondary structure of xylanase, except that of D21E, which shows a little variation. Furthermore, mutations of Glu-93 and Glu-182 resulted in a drastic decrease in the specific activity of xylanase as compared with mutation of Asp-21. On the basis of these results we propose that Glu-93 and Glu-182 are the best candidates for the essential catalytic residues of xylanase.

Aspartic Acid↗
PubMed1992

Purification and characterization of a new member of the S-100 protein family from human placenta.

A novel Ca(2+)-binding protein which is termed S-100P was purified from human placenta with a hydrophobic column followed by an anion exchange column and reverse phase high performance liquid chromatography (HPLC). Molecular mass of the protein was 10 kDa according to sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis. Using immunoblotting technique, anti-human calcyclin antibodies did not bind to the S-100P. Isoelectric point of S-100P was pI = 4.6. S-100P did not formed disulfide-linked dimer. Calcium binding ability was proved by UV difference spectrometry, urea/alkaline gel electrophoresis, and 45Ca overlay technique. A ninety amino acid sequence of S-100P was determined. It is 49% identical with human S-100 beta, 38% with human calcyclin, and 37% with human cystic fibrosis antigen.

Amino Acid Sequence↗
PubMed1990

The diagnostic and prognostic value of pretreatment serum creatine kinase BB levels in patients with neuroblastoma.

The serum levels of the BB isozyme of creatine kinase (CK-BB) and neuron-specific enolase (NSE) were measured before therapy in 35 patients with neuroblastoma. Sixty percent (21 of 35) of neuroblastoma patients had CK-BB levels higher than 11 ng/ml. The extent of disease was associated with an increased incidence of elevated serum CK-BB levels. The highest pretreatment serum CK-BB titers were found in patients with Stage IV disease. A strong correlation between the pretreatment CK-BB level and the outcome in patients with neuroblastoma was observed. Eleven (79%) of 12 patients who had a serum CK-BB level greater than 15 ng/ml died, and eight of ten (80%) who had a serum level less than 11 ng/ml were alive and tumor free after 2 years. A positive linear correlation between the pretreatment CK-BB and NSE (n = 35, r = 0.695) levels was found.

Biomarkers, Tumor↗
PubMed1986

Age changes of myofibrils of human minor pectoral muscle.

Micro- and ultramicromeasuring studies have been made on the age changes of surgically resected minor pectoral muscles in 200 Japanese females of various ages (26-80 years). With advancement of age, muscle fibers of type I decreased in number and increased in size, and the age-related increase in size is not considered to be due to an increase in number of myofibrils but seems to be due to an increase in their volume resulting from an increase in the number of myofilaments.

Adult↗
PubMed1986

Biological and clinical implication of neuron-specific enolase and creatine kinase BB in small cell lung cancer.

The specificity of neuron-specific enolase (NSE) and creatine kinase BB (CK-BB) for small cell lung cancer (SCLC) was determined by biological and immunohistochemical procedures in lung cancer tissues and cultured cell lines. Average values of extractable NSE and CK-BB of SCLC tissues were significantly higher than those of non-SCLC and normal lung tissues. A large amount of NSE and CK-BB was demonstrated in SCLC cell lines. Immunohistochemical examination showed positive staining for NSE and CK-BB in most cases of SCLC and in a few cases of non-SCLC. From these data NSE and CK-BB should be considered to be highly specific for SCLC. In a clinical study serum values exceeding 10 ng/ml for NSE and 1.5 ng/ml for CK-BB were set as positive for the enzymes. Positive rates in SCLC were 71.4% for NSE and 65.3% for CK-BB, which were significantly higher than those in non-SCLC. All positive cases were in an advanced stage. Consecutive daily NSE determinations during induction chemotherapy showed transient elevation immediately after the initiation of drug administration (tumor lysis syndrome), followed by a decline to normal range in responders. This phenomenon seems to indicate tumor sensitivity to cytotoxic drugs. NSE positive non-SCLC was as sensitive to cytotoxic drugs as SCLC. These findings indicate that lung cancer with elevated serum NSE and CK-BB levels at diagnosis should be strongly suspected of being SCLC in the advanced stage.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1984

Immunoelectron microscopic studies on peripheral T-cell lymphomas using monoclonal antibodies.

Ultrastructural comparison between helper/inducer and suppressor/cytotoxic type cells in peripheral T-cell lymphomas was made using the immunoperoxidase technique. The nuclei of T4 positive cells were more irregular in outline than those of T8 positive cells, and nuclear irregularity was further pronounced in the cells of the adult T-cell leukemia/lymphoma which were of helper/inducer type cells. The suppressor/cytotoxic type cells possessed in their cytoplasm scattered dense bodies encircled by distinct membranes, although they also contained clustered dense bodies. On the other hand, the helper-inducer type cells had only clustered dense bodies. No other significant differences were observed regarding other cytoplasmic organelles between T4 positive cells and T8 positive cells. The existence of the peripheral T-cell lymphomas with "double-markers" which possessed surface antigens for both helper/inducer and suppressor/cytotoxic subsets was also demonstrated.

Antibodies, Monoclonal↗
PubMed1984

Age changes in size and number of muscle fibers in human minor pectoral muscle.

Micromeasuring studies have been made on the senile changes of the surgically resected minor pectoral muscles in 200 Japanese females of various ages (26-80 years). The microscopic differentiation between type I (red) and type II (white) fibers were made by the histochemically demonstrated myosin-ATPase activity with frozen sections and also by the immunohistochemical demonstration of beta-enolase in the paraffin sections with indirect antibody method. The decrease with age in weight of the muscle was not markedly observed. Muscle fibers of type I were significantly decreased in number and increased in size after 60 years of age. However, size of muscle fibers of type II decreased gradually after 40 years of age. However, size of muscle fibers of type II decreased gradually after 40 years of age. Total volume of type I muscle fibers was not changed according to age, on the contrary, that of the type II fibers decreased significantly after 60 years of age.

Adenosine Triphosphatases↗