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Biomedical subjects

T Hamamoto

Publications and source records attributed to T Hamamoto.

At least 109 records · Page 6Linked to original sources
PubMed1993

[A case of Legionnaires' disease due to aspiration of hot spring water and isolation of Legionella pneumophila from hot spring water].

We report a case of fulminant pneumonia that was due to aspiration of contaminated hot spring water and was not affected by beta-lactam antibiotics. We suspected that the patient had Legionnaires' disease and treated the clinical symptoms with erythromycin. Legionellaceae could not be isolated from sputum or lung biopsy material, but an elevated titer to Legionella pneumophila serogroup 4 was found by indirect immunofluorescence test. We diagnosed the patent as having Legionnaires' disease with improved clinical symptoms. Furthermore, we went to the hot spring that he visited and tried to isolate Legionellaceae. Hot spring water was collected from the bathroom and water, hot water, and shower water from the guest-room. After using a low-pH method, samples were cultured on BCYE alpha medium. Serogroups are classified by agglutination method with immune rabbit serum. As a result, we successfully isolated Legionella pneumophila serogroup 4 from hot spring water (42 degrees C) from the bath. No bacteria could be isolated from the other samples. Therefore, we believe that this case of Legionnaires' disease was caused by aspiration of contaminated hot spring water. The infection route of Legionnaires' disease is unclear. There are no previous reports of isolation of Legionellaceae from Japanese hot springs. This case would provide important information when considering the infection route of Legionnaires' disease in Japan.

Accidents↗
PubMed1992

Primary structure of the alanine carrier protein of thermophilic bacterium PS3.

Purified alanine carrier proteins were cleaved into peptides either chemically after solubilization in 1,1,1,3,3,3-hexafluoro-2-propanol or proteolytically with lysylendopeptidase. From the amino acid sequence analyses of these peptides, we synthesized a DNA probe and utilized it for successful cloning of a gene encoding the alanine carrier protein (acp gene). The 5'-flanking region was determined by an inverse polymerase chain reaction, and an open reading frame consisting of 1,335 nucleotides was found. The amino acid sequence deduced from the open reading frame consists of 445 amino acids, and all the partial amino acid sequences determined are included in the sequence. Although the calculated M(r) of 47,803 is significantly larger than the apparent M(r) of 42,500 as reported previously (Hirata, H., Kambe, T., and Kagawa, Y. (1984) J. Biol. Chem. 259, 10653-10656), an in vitro translation experiment revealed that the product of the acp gene migrates at a position coinciding with that of the purified alanine carrier. Hydropathy analysis suggests that the protein contains at least 8 hydrophobic segments presumably spanning membrane. A homology search on a database reveals relatively high scores of homology with either the Escherichia coli melibiose carrier or the human Na+/glucose symporter, particularly in the region from Leu246 to Glu286. Furthermore, the region also reveals low but significant similarities to other Na(+)-coupled symporters.

Amino Acid Sequence↗
PubMed1992

Characterization of proteoglycan degradation by calpain.

Degradation of cartilage proteoglycans was investigated under neutral conditions (pH 7.5) by using pig kidney calpain II (EC 3.4.22.17; Ca(2+)-dependent cysteine proteinase). Aggregate and monomer degradation reached a maximum in 5 min at 30 degrees C when the substrate/enzyme ratio was less than 1000:1. The mode of degradation was limited proteolysis of the core protein; the size of the products was larger than that of papain-digested products and comparable with that of trypsin-digested products. The hyaluronic acid-binding region was lost from the major glycosaminoglycan-bearing region after incubation with calpain II. Calpains thus may affect the form of proteoglycans in connective tissue. Ca(2+)-dependent proteoglycan degradation was unique in that proteoglycans adsorb large amounts of Ca2+ ions rapidly before activation of calpain II: 1 mg of pig cartilage proteoglycan monomer adsorbed 1.3-1.6 mu equiv. of Ca2+ ions before activation of calpain II, which corresponds to half the sum of anion groups in glycosaminoglycan side chains. This adsorption of Ca2+ was lost after solvolysis of proteoglycan monomer with methanol/50 mM-HCl, which was used to desulphate glycosaminoglycans. Therefore cartilage proteoglycans are not merely the substrates of proteolysis, but they may regulate the activation of Ca(2+)-dependent enzymes including calpains through tight chelation of Ca2+ ions between glycosaminoglycan side chains.

Animals↗
PubMed1992

Analysis of functional domains of endoglucanases from Clostridium cellulovorans by gene cloning, nucleotide sequencing and chimeric protein construction.

The nucleotide sequence of engD, an endo-beta-1,4-glucanase gene from Clostridium cellulovorans was determined (Genbank Accession No. M37434). The COOH-terminal part of the gene product, EngD, contained a Thr-Thr-Pro repeated sequence followed by a region that has homology to the exoglucanase of Cellulomonas fimi. EngD and EngB, another C. cellulovorans endoglucanase, show 75% amino acid sequence homology at their NH2-termini, in contrast to their carboxyterminal domains which show no homology. EngD had endoglucanase activity on carboxymethylcellulose (CMC), cellobiosidase activity on p-nitrophenyl-cellobioside (p-NPC), and partial hydrolytic activity on crystalline cellulose (Avicel), while EngB showed hydrolytic activity against only CMC. Chimeric proteins between EngB and EngD were constructed by exchanging the non-homologous COOH-terminal regions. Chimeric proteins that contained the NH2-terminus of EngD retained cellobiosidase activity but chimeras with the EngB NH2-terminus showed no cellobiosidase activity. Hydrolysis of crystalline cellulose (Avicelase activity) was observed only with the enzyme containing the EngD NH2-terminus and EngD COOH-terminus.

Amino Acid Sequence↗
PubMed1992

Modelling of frequency-dependent effects of lignocaine homologues on the maximum upstroke velocity of action potentials in guinea-pig papillary muscles.

1. The effects of 14 lignocaine homologues on the maximum upstroke velocity (Vmax) of the action potentials (AP) were studied in guinea-pig papillary muscles. These drugs possess one, two or three methyl groups in different positions: an ortho-chloro, -carbomethoxy or -ethyl group instead of an ortho-methyl group; or an N-butyl group instead of an N-diethyl group in lignocaine molecules. 2. At 50-100 mumol/L, six drugs possessing two ortho substituents (but not the other eight) reduced Vmax more prominently at 2-4 Hz than at 1 Hz, and slowed the time courses of recovery of the premature responses. None of the drugs affected resting potential. 3. Besides the two-state piecewise exponential model (models I and II) frequently used, a time-dependent and time-independent, two-state model (model III) was formulated and applied to these experimental data. The above two groups were effectively distinguished by the difference of the estimated association and dissociation rate constants (model II) and equilibrium constants for phasic state (model III) and for resting (model II) or tonic (model III) states. 4. The equilibrium constants for resting or tonic state correlated well with log P (where P = the n-octanol: water partition coefficients), but correlated better with an indicator variable that denotes the existence of two ortho substituents, suggesting the importance of the contribution of steric factors to the activity.

Action Potentials↗
PubMed1992

Intravenous gamma-globulin therapy in Diamond-Blackfan anemia.

Pure red cell aplasia (PRCA) is a rare disorder of erythrocyte production which is believed to have an autoimmune basis in most cases. Diamond-Blackfan anemia (DBA) is one type of congenital PRCA. Since PRCA has been reported to respond to intravenous gamma-globulin (IVGG) therapy, we administered IVGG to a 2 year old girl with DBA resistant to corticosteroids and observed slight therapeutic effect.

Adrenal Cortex Hormones↗
PubMed1992

A case of ulcerative colitis induced by oral ferrous sulfate.

We report a case of ulcerative colitis (UC) in a 15 year old female undergoing treatment for anemia with oral ferrous sulfate. We suggest that the oral ferrous sulfate initiated the typical symptoms of UC in this case. This case is the first clinical report to our knowledge supporting the 'iron-catalysed oxidant-mediated ischemic injury theory' of UC.

Administration, Oral↗
PubMed1992

Increased plasma tumour necrosis factor-alpha concentration in atopic dermatitis.

Plasma tumour necrosis factor-alpha (TNF-alpha) was measured in 15 children with atopic dermatitis, 13 children with bronchial asthma, and 11 healthy controls. Plasma TNF-alpha concentration was increased in atopic dermatitis and the magnitude of the increase was correlated with the severity of the dermatitis but TNF-alpha concentration was not increased in bronchial asthma. A significant correlation was found between plasma TNF-alpha and plasma histamine concentrations in atopic dermatitis. The data suggest that the overproduction of TNF-alpha is associated with increased plasma histamine concentration, and might play a part in the pathophysiological mechanism of atopic dermatitis.

Adolescent↗
PubMed1992

Expression of human metallothionein-II fusion protein in Escherichia coli.

In order to obtain antibody against metallothionein-II (MT-II), a capsid protein metallothionein fusion protein was prepared. A gene encoding human MT-II was cloned into a plasmid for expression of MT fusion protein in Escherichia coli. MT cDNA was generated from human astrocytoma U373MG and amplified by polymerase chain reaction. The nucleotide sequence was identical to reported MT-II. The cDNA was inserted into plasmid pGEM EXTM-2 which carries the T7 promoter and T7 phage 10A major head protein. This expressed phage protein-MT fusion protein, has a molecular weight of 37kDa, forms inclusion bodies and constitutes about 20% of the total protein in transformed E. coli.

Amino Acid Sequence↗
PubMed1992

[Intra-arterial chemotherapy with granulocyte colony-stimulating factor for breast cancer before surgical treatment].

Intra-arterial chemotherapy (IAC) for far advanced breast cancer is now performed as a routine adjuvant chemotherapy before surgical treatment. However, the following problems remain unsolved; (1) serious adverse reactions such as myelosuppression, (2) unsuccessful insertion of catheter into the internal thoracic artery, and (3) long waiting-period from IAC to surgical treatment. The present studies were conducted to evaluate the utility of a one-route IAC, in which the subclavian artery alone is used, and the efficacy of granulocyte colony-stimulating factor (G-CSF). There was no significant difference in the antitumor effect between the patients with two-route IAC, in which both internal thoracic artery and subclavian artery are used, and the patients with one-route IAC. Administration of G-CSF in combination with IAC reduced both the frequency and the severity of IAC-induced side effects. G-CSF administration during IAC was more effective than after IAC. G-CSF prevented IAC-induced myelo-suppression and/or accelerated recovery from this complication and thus reduced significantly the waiting-period before surgical treatment.

Breast Neoplasms↗
PubMed1991

Gene structure of heat shock proteins 61KDa and 12KDa (thermophilic chaperonins) of thermophilic bacterium PS3.

Heat shock proteins 60 (hsp60) and 10 (hsp10) are essential for the formation and restoration of many supramolecular structures. For reconstitution of these structures, we isolated stable hsps of 61kDa and 12kDa, which are similar to hsp60 and hsp10, respectively, from the supernatant fraction of thermophilic bacterium PS3 by ATP-Agarose chromatography. Using synthetic DNA of the deduced sequence, the 1.6kbp double stranded DNA encoding both proteins was obtained by the polymerase chain reaction (PCR). The complete sequence of the resulting reading frames showed high homology to those of the genes encoding GroEL (hsp60) and GroES (hsp10) of E. coli, and hsp60s and hsp10s of several other species. The genes for the 12K and 61K were present in the same operon. 61K was also partially similar to the F1 alpha subunit of thermophilic ATP synthase, which is highly reconstitutable to form the alpha beta complex.

Amino Acid Sequence↗
PubMed1991

Aplastic anemia associated with systemic lupus erythematosus.

Hematologic complications of systemic lupus erythematosus (SLE) usually involve peripheral destruction of blood cells. We report a case of aplastic anemia associated with SLE observed during the remission phase of SLE 3 months after the beginning of treatment. CD8+ T cells in the patient's bone marrow may have suppressed maturation of hematopoietic progenitor cells, which may have induced the aplastic anemia associated with SLE. Repeated therapy with high-dose methylprednisolone resulted in lasting remission.

Anemia, Aplastic↗