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Biomedical subjects

T Hamamoto

Publications and source records attributed to T Hamamoto.

At least 127 records · Page 7Linked to original sources
PubMed1991

Immunohistochemical and biochemical demonstration of calcium-dependent cysteine proteinase (calpain) in calcifying cartilage of rats.

Calpain is a Ca2(+)-dependent cysteine proteinase that has neutral pH optima. There are two classes of calpains that differ in their optimal calcium ion concentration for enzymatic activity. Calpain I requires a low concentration of Ca2+ for activation, and calpain II requires a much higher Ca2+ concentration. This report describes the immunohistochemical and biochemical demonstration of calpain II in calcifying cartilage in rats and also the degradation of the cartilage proteoglycan subunit by calpain II. Immunoperoxidase (peroxidase-antiperoxidase) staining of the frozen sections of the knee joint from 3-day-old and 6-day-old Wistar rats, using polyclonal antibodies against the respective heavy subunits of calpains I and II, showed positive staining only with the anti-calpain II antibody in the hypertrophic chondrocytes and surrounding cartilaginous matrix of the growth cartilage. Diethylaminoethyl-cellulose chromatography of the cartilaginous extract from 3-day-old rats showed a peak of caseinolytic activity attributable to calpain as well as an inhibitory peak of calpastatin, a specific inhibitor protein of calpains. Immunoblotting using the anti-calpain II antibody of the calpain peak demonstrated identity with the heavy subunit of calpain II (80 kDa). Proteoglycan-degrading activity of calpain was assessed using porcine kidney calpain II and the porcine articular cartilage proteoglycan subunit. After incubation in the presence of Ca2+, degradation of proteoglycan was demonstrated by the change of the elution position on Sepharose-2B chromatography. It is possible that calpain functions as one of the proteoglycan-degrading proteolytic enzymes of growth cartilage. Intracellular localization of calpain in hypertrophic chondrocytes also suggests a role in the hypertrophic process of the chondrocyte in growth cartilage.

Animals↗
PubMed1991

Nucleotide sequence and characteristics of endoglucanase gene engB from Clostridium cellulovorans.

An endoglucanase gene, engB, from Clostridium cellulovorans, previously cloned into pUC19, has been further characterized and its product investigated. The enzyme, EngB, encoded by the gene was secreted into the periplasmic space of Escherichia coli. The enzyme was active against carboxymethylcellulose, xylan and lichenan but not Avicel (crystalline cellulose). The sequenced gene showed an open reading frame of 1323 base pairs and coded for a protein with a molecular mass of 48.6 kDa. The mRNA contained a typical Gram-positive ribosome-binding site sequence GGAGG and a sequence coding for a putative signal peptide. There is high amino acid and base sequence homology between the N-terminal regions of EngB and another C. cellulovorans endoglucanase, EngD, but they differ significantly in their C-termini. Deletion analyses revealed that up to 32 amino acids of the N-terminus and 52 amino acids of the C-terminus were not required for catalytic activity. The conserved reiterated domains at the C-terminus of EngB were similar to those from endoglucanases from other cellulytic bacteria. According to our deletion analyses, this region is not needed for catalytic activity.

Amino Acid Sequence↗
PubMed1991

Epidermoid cyst derived from an accessory spleen in the pancreas. A case report with literature survey.

A rare case of splenic epidermoid cyst (SEC) of the pancreas discovered in a 32-year-old Japanese female is reported. The lesion, 5 x 6 cm in size including caseous material and serous fluid in the lumen, was discovered by ultrasonography and computed tomography at the tail of the pancreas and was easily removed. Histopathologically, the cystic wall consisted of three components: the inside was lined by mature squamous epithelium with keratinization, the middle layer consisted of splenic pulp with a sinus structure, and the peripheral layer was dense fibrous connective tissue in which some involutional pancreatic ducts and islets were recognized. The literature about SEC of the pancreas is discussed in comparison with other types of epidermoid cyst including lymphoepithelial cyst and dermoid cyst in the pancreas.

Adult↗
PubMed1990

Cytosol type electrolyte medium suitable for long term growth of human cells with very low membrane potential.

Culture media for mammalian cells contain electrolytes at concentrations that approximate those of the extracellular fluid (ECF). However, we observed that HeLa strain cells can grow in a cytosol type, serum-free, high amino acid medium (KN13) in which the concentrations of K+, Mg2+ and Pi were increased to about 10 times those in ECF by replacing NaCl. The Ca2+ concentration of KN13 is 10% of that in ECF. The additions of Mg2+ and Pi are essential to prevent the harmful effect of a high concentration of K+ in the medium. Even an increase in the K/Na ratio to 7 and 9 permitted growth for at least 2 weeks and 4 days, respectively. HeLaP3 cells adapted to KN13 (HeLaK cells) have proliferated (4 fold/week) for 4 years in this medium. The Na,K-ATPase of HeLaK cells was the alpha 1 isoform. HeLaK cells in KN13 medium have a lower membrane potential (-3.0 +/- 6.1 mV) than that of the original HeLaP3 cells in DM160 (-26 +/- 10 mV).

Base Sequence↗
PubMed1990

Cloning of Clostridium cellulovorans endo-1,4-beta-glucanase genes.

A Clostridium cellulovorans lambda gt11 gene bank was screened for endo-1,4-beta-glucanase [EC 3.2.1.4, EGase, Carboxy Methyl Cellulase (CMCase)] genes using a chromogenic substrate. Three genes (engA, engB, and engC) were isolated. The engB expressed the most active CMCase. The engA encoded a bifunctional enzyme that displayed endo-1,4-beta-glucanase and beta-glucosidase activities. The three recombinant glucanases, when expressed in Escherichia coli, were partially degraded into multiform active enzymes as evidenced by their SDS-PAGE-CMC zymograms. None of the clones could degrade crystalline cellulose, thus supporting the hypothesis that the integrity of the C. cellulovorans cellulase complex was essential for its 'true cellulase' activity.

Cellulase↗
PubMed1990

Nonoxidative metabolism of ethanol in the pancreas; implication in alcoholic pancreatic damage.

Alcohol dehydrogenase activity and fatty acid ethyl ester synthase activity were measured in various organs of male Wistar strain rats. The mean (+/- SE) values of alcohol dehydrogenase activity in liver, testis, pancreas and brain were 223 +/- 34, 35 +/- 13, 27 +/- 17 and 24 +/- 15 nmol/hr/mg protein, respectively, but not detectable in heart and skeletal muscle. Fatty acid ethyl ester synthase activity in pancreas, liver, testis and heart were 1348 +/- 263, 23 +/- 14, 17 +/- 3 and 2 +/- 1 nmol/hr/mg protein, respectively, but not detectable in brain and skeletal muscle. Alcohol dehydrogenase activity, fatty acid ethyl ester synthase activity, fatty acid ethyl ester content and amylase activity were measured in pancreas of rat after 7 weeks of ethanol feeding. Compared with control rats, ethanol-fed rats had normal fatty acid ethyl ester synthase activity and alcohol dehydrogenase activity. However, fatty acid ethyl ester content increased five-fold and amylase activity decreased up to 20% of the control group. Fatty acid ethyl ester content was inversely correlated with amylase activity. These results suggest that fatty acid ethyl ester may be responsible for the development of pancreatic damage by ethanol.

Acyltransferases↗
PubMed1990

Biochemical demonstration of calpains and calpastatin in osteoarthritic synovial fluid.

Calpains (calcium-dependent cysteine proteinases; optimum pH 7.0-7.5) have been regarded as intracellular proteinases. We examined the cell-free components of synovial fluid from 14 patients with osteoarthritis and demonstrated the existence of calpains, as the caseinolytic activities of chromatographic fractions, together with calpastatin, the specific endogenous inhibitor of calpains. The presence of these calpains and calpastatin was verified by immunoblotting with their respective specific antibodies. Calpain fractions showed proteoglycan-degrading activity. The results suggest that the calpain-calpastatin system may contribute to the turnover of cartilage matrix components.

Aged↗
PubMed1990

Agranulocytosis following infectious mononucleosis.

A girl developed acute agranulocytosis (45/mm3), 37 days after the onset of infectious mononucleosis. The bone marrow showed myeloid hyperplasia with maturation arrest and erythroid hypoplasia. A normal amount of colony forming units of granulocytes and macrophages (CFU-GM) colonies with a relative high number of clusters was observed. Neither anti-neutrophil antibodies nor circulating inhibitors of colony growth were found in serum. Granulocyte and macrophage colony stimulating factor (GM-CSF) activity in the patient's serum rose at this time. The agranulocytosis lasted 5 days and her clinical state soon improved. These results suggested that agranulocytosis was presumably not due to serum factors, including auto-antibodies and/or suppressive substances, and that Epstein-Barr virus (EBV) had some direct or indirect effect on the marrow cells of the myeloid series.

Agranulocytosis↗
PubMed1990

[Eight cases of diphyllobothriasis].

Eight cases of diphyllobothriasis have been experienced in the Juntendo University Hospital. Seven of the 8 patients excreted tapeworm fragments. Eggs of Diphyllobothrium latum were found in the feces in 5 cases. One patient had a history of ingestion of raw trout (Sushi), and 2 raw salmon. One might have been infected in foreign countries, and 3 could not tell the source of infection. Bithoinol was administered orally to 7 patients. Four of the 7 excreted the worm and the scolex was recognized in three of the four. Neither recurrence nor abnormal findings have been recognized so far.

Adult↗
PubMed1990

[Study on specific IgE antibodies in pediatric allergic patients by CAP system].

The CAP system is a new method to detect specific IgE antibodies and is an advanced method of the traditional paper disc RAST. Our result suggests a significant correlation between scores obtained with the CAP system and those with the traditional RAST. Since specific IgE antibodies against multiple allergens can be measured with the CAP system, we studied 5 food allergen specific IgE antibodies (Fx5) in cases of infantile atopic dermatitis. This study indicates a good correlation between the Fx5 scores and clinical symptoms of these patients. Thus, it is concluded that the CAP system is useful for screening IgE antibodies against multiple food allergens in cases of infantile atopic dermatitis.

Adolescent↗
PubMed1990

Five-year results of bipolar arthroplasty with bone grafts and reamed acetabula for osteoarthritis in young adults.

Bateman universal proximal femoral arthroplasty combined with acetabular reaming was performed in 35 cases of osteoarthritis of the hip joint. The patients were from 21 to 59 years of age (average, 41 years of age) at the time of operation. The postoperative outcome for a middle term ranging from two to eight years, with an average of five years and nine months, was studied along with postoperative migration of the outer head. The clinical outcome, assessed by the evaluation criteria for hip function proposed by the Japanese Orthopaedic Association, was favorable. A stable average score of greater than 80 occurred for eight years postoperatively; the average preoperative score was 45. Of the 35 cases, seven cases (20%) had an upward migration of the outer head, and one case (2.9%) had an inward migration of 5 mm or more, but the migration did not affect the clinical outcome in any case. There was no certain relationship between the degree of rotation of the outer head and the extent of its migration. Migration of the outer head was prevented by postoperative exercise, in which total loading was initiated after the completion of the radiolucent zone around the outer head and its circumferential zone of osteosclerosis.

Acetabulum↗
PubMed1989

Oxygen radicals in influenza-induced pathogenesis and treatment with pyran polymer-conjugated SOD.

The pathogenicity of influenza virus infection in the mice involves, at least in part, overreaction of the immune responses of the host rather than a direct effect of virus multiplication. Xanthine oxidase, which is responsible for the generation of oxygen free radicals, was elevated in serum and lung tissue of mice infected with influenza virus. To test the theory that oxygen-free radicals are involved in pathogenesis, free radicals were removed by injecting superoxide dismutase (SOD), a specific superoxide radical scavenger, which was conjugated with a pyran copolymer. The conjugate protected mice against a potentially lethal influenza virus infection if administered 5 to 8 days after infection. These findings indicate that oxygen radicals are important in the pathogenesis of influenza virus infection, and that a polymer-conjugated SOD has therapeutic potential for this virus infection and other diseases associated with free radicals.

Animals↗
PubMed1989

Sodium channel-blocking properties of flecainide, a class IC antiarrhythmic drug, in guinea-pig papillary muscles. An open channel blocker or an inactivated channel blocker.

Effects of flecainide (a class IC antiarrhythmic drug) on the maximum rate of rise (Vmax) of action potentials (APs) were studied in guinea-pig papillary muscles, with special reference to their time, voltage, and action potential duration (APD) dependence in the presence and absence of nicorandil. Nicorandil was used to shorten APD, i.e., the time period of inactivation state of sodium channels. APs were recorded from the preparations using standard microelectrode techniques. Flecainide (5 mumol/l) reduced Vmax without changing resting potential, AP amplitude, APD50, and APD90 examined at 1 Hz. The drug shifted the normalized Vmax-membrane potential curve (examined at 1/60 Hz) in the hyperpolarizing direction by 3.1 +/- 0.8 mV (n = 6) (voltage dependence). The drug caused a frequency-dependent reduction of Vmax at greater than or equal to 0.1 Hz, developed a use-dependent reduction of Vmax at 1 Hz with an onset time constant of 11.7 +/- 0.4 s (n = 6), and slowed the recovery process of Vmax, whose resultant recovery time constant was 19.9 +/- 1.2 s (n = 6) (time dependence). These flecainide-induced time-dependent reductions of Vmax were not antagonized by nicorandil (1 mmol/l) which shortened APD to about 1/4 of control (APD independence). These results suggest that flecainide is primarily an open channel blocker because its channel-blocking actions are independent of APD or the time period of inactivation.

Action Potentials↗
PubMed1989

Construction of a chimeric series of Bacillus cyclomaltodextrin glucanotransferases and analysis of the thermal stabilities and pH optima of the enzymes.

The cyclomaltodextrin glucanotransferase (CGTase, EC 2.4.1.19) gene from the alkalophilic Bacillus sp. strain no. 17-1 was cloned in Escherichia coli. The cloned CGTase gene consisted of a single open reading frame which would encode a polypeptide of 713 amino acids, and the first 27 amino acid residues comprised a signal peptide. The nucleotide sequence and the amino acid sequence of this CGTase (CGTase 17-1) gene had strong homology with those of the CGTase (CGTase 38-2) gene previously cloned in our laboratory from the alkalophilic Bacillus sp. strain no. 38-2, although the enzymic properties of the CGTase 17-1 were distinct from those of the CGTase 38-2. To analyse those enzymic properties further, we constructed 12 chimeric CGTases using three restriction nuclease sites and compared the enzymic properties of the chimeric CGTases. The N-terminal part of the enzyme was important for heat stability, and the pH-activity profile was influenced by both the N- and the C-terminal parts. A third segment was less important for enzymic properties.

Amino Acid Sequence↗
PubMed1989

[Fluconazole treatment of systemic mycoses].

Efficacies of fluconazole, a new triazole antifungal agent, were evaluated in 11 cases of systemic mycoses (1 case each of candiduria, pulmonary cryptococcosis, pulmonary aspergillosis, pulmonary penicilliosis and suspected fungal pulmonary infection, and 3 cases each of candidemia and Candida endophthalmitis). The clinical efficacies were excellent or good in 8 out of 9 cases and poor in 1. Side effects observed were mild with 1 incident each of gastrointestinal symptom and reversible leukopenia. This drug appears to be promising in treatment of systemic mycoses.

Adolescent↗
PubMed1989

Effects of lidocaine alone and in combination with tetraethylammonium on the maximum upstroke velocity in guinea-pig papillary muscles.

Effects of 18.5 mumol/l lidocaine on the Vmax in the absence and presence of 10 mmol/l tetraethylammonium chloride (TEA), which specifically prolongs the action potential duration with little effects on Vmax, were studied in guinea-pig papillary muscles in a 10 mmol/l K+ Tyrode solution. The frequency-dependent reduction of Vmax was significantly increased at high frequencies (3 and 4 Hz) in the presence of lidocaine plus TEA. A simulation study was performed under the assumption that lidocaine interacts with open, inactivated and resting sodium channels and that TEA specifically prolongs the inactivated state, and a reasonable fit to the experimental Vmax changes was obtained. There were no significant differences between the effects of lidocaine alone and lidocaine plus TEA on the tonic blocks, time constants and zero-time intercepts of reactivation process of Vmax. The F-test shows that these reactivation processes in all preparations examined are described sufficiently well by monoexponential functions, that is, under the assumption of the linear relationship between available sodium conductance and Vmax. The finding that a nonlinear model does not significantly improve the fit indicates the possibility that the nonlinearity may not be prominent under the present experimental conditions.

Action Potentials↗