Biomedical subjects

T Amano

Publications and source records attributed to T Amano.

At least 199 records · Page 11Linked to original sources

PubMed1995

Prevalence of hepatitis B surface antigen, hepatitis B e antigen and antibody, and antigen subtypes in atomic bomb survivors.

On the basis of previous studies showing an association between hepatitis B surface antigen (HBsAg) positivity and radiation exposure in atomic bomb (A-bomb) survivors, we investigated further the active state of hepatitis B virus (HBV) infection by incorporating tests for hepatitis B e antigen (HBeAg) and hepatitis B e antibody (anti-HBe) and HBsAg subtypes into our biennial health examinations. Among 6548 A-bomb survivors for whom HBsAg was assayed between July 1979 and July 1981, 129 persons were HBsAg positive. HBeAg and anti-HBe were measured in 104 of these persons and subtypes of HBsAg in 98 persons. Among those exposed to radiation (average liver dose 0.58 Sv), the odds ratio of HBsAg positivity tended to increase with radiation dose (P for trend = 0.024). The P values for association between the prevalence of HB e antigen and radiation dose and between the prevalence of anti-HBe and radiation dose were 0.094 and 0.17, respectively. The HB antigen subtype adr was predominant over other subtypes in both Hiroshima and Nagasaki, but the distribution of subtypes did not seem to differ in relation to radiation dose. These results suggested that A-bomb survivors remain in an active state of HBV infection and that the mechanism(s) of seroconversion may be impaired.

Adolescent↗

PubMed1995

[Empyema caused by perforation of metastatic colon cancer: a case report].

The patient was a 51-year-old female, underwent total gastrectomy for gastric cancer 6 years ago. She was admitted to a local hospital with the complaint of fever, the chest X-ray showed niveau in the left pleural cavity. Fecal material flowed out by drainage. Barium enema showed fistula of diaphragma from transverse colon. She was transferred to our hospital. Partial transverse colon resection and removal of the diaphragma fistula were performed. The colon tumor was histologically determined to be metastasis from gastric cancer with thoracic empyema.

Adenocarcinoma↗

PubMed1995

Specific antibody patterns of Wistar rats inoculated with third stage larvae of Anisakis simplex.

Levels of excretory-secretory (ES)-specific antibody were measured in Wistar rats inoculated with 1, 5, or 20 third stage larvae (L3) of Anisakis simplex. Primary inoculation induced ES-specific IgM and IgG titers, paralleling inoculum size. Secondary inoculations resulted in an IgM and IgG titer augmentation in 1 or 5 larvae-inoculated animals to levels comparable to those of animals inoculated with 20 larvae, but titers in high inoculum animals did not increase upon secondary inoculation. Primary inoculation induced low ES-specific IgE antibody titers. However, secondary inoculation produced a different pattern than with IgM or IgG titers. Instead of titers equivalent to animals receiving more larvae, rats receiving 1 larva developed higher IgE titers than rats receiving larger inoculums. IgE titers of single larvae-inoculated rats peaked at 3-5 days after secondary inoculation but disappeared by day 14. The time course of IgE production is therefore consistent with duration of the infection. As the natural infection typically involves few larvae, monitoring ES-specific IgE may be a useful diagnostic tool for human intestinal anisakiasis.

Animals↗

PubMed1995

[A case of systemic lupus erythematosus associated with severe fibrinoid necrosis located mainly in the glomerular afferent arteriole].

We report here, a patient of systemic lupus erythematosus (SLE) with severe fibrinoid necrosis in the afferent arteriole of the glomerulus, in whom antiphospholipid antibody might have contributed to the pathogenesis. A 24-year-old female who was suffering from severe anemia with fragmented red blood cells, acute renal failure and thrombocytopenia, was admitted to our hospital. Further examinations revealed findings compatible with active lupus nephritis. Moreover, she was found to be positive for antiphospholipid antibody, and anticardiolipin antibody, as well as for lupus anticoagulant and syphilis test. Intensive treatment by methylprednisolone pulse therapy, hemodialysis, and double filtration plasmapheresis were performed. However, 13 days after admission she died suddenly because of intracranial hemorrhage. Pathological investigation of renal tissue revealed severe fibrinoid necrosis of the arterioles mainly in the glomerular afferent arteriole associated with diffuse proliferative lupus nephritis. In this case, hemolytic uremic syndrome (HUS) was associated with SLE. Antiphospholipid antibody was considered to be not only an accelerator in the arterial lesions of HUS, but also an initiator of HUS itself.

Adult↗

PubMed1995

[Low-dose cytarabine ocfosfate therapy in an elderly acute myelogenous leukemia].

A 71-year-old man was admitted for severe anemia. Bone marrow puncture revealed 48% of blast cells. A diagnosis of acute myelogenous leukemia (AML-M 4) was made. As the patient was old, we administered 300mg of cytarabine ocfosfate (SPAC) for 21 days. Blast cells in bone marrow decreased 5.6%, and SPAC was considered effective. We treated him with the same dose of SPAC for 14 days after a 21-day interval from the end of the first treatment. Although leukemic cells were still seen in bone marrow after two treatments, we considered him in partial remission, and he was discharged. After discharge, the hematological findings remain almost normal with intermittent treatment of 150 mg of SPAC for over one year. Thus, cytarabine ocfosfate might be useful in elderly AML patients.

Aged↗

PubMed1995

Blepharophimosis, ptosis, epicanthus inversus, telecanthus, amblyopia, and menstrual abnormality in sisters.

Two sisters with blepharophimosis, ptosis, epicanthus inversus, and telecanthus were examined. Both patients also had amblyopia in the right eye and menstrual abnormalities associated with elevated serum luteinizing hormone and follicle-stimulating hormone. The patients' father was suspected of having blepharophimosis and ptosis. It is possible that the blepharophimosis syndrome observed in this family is of autosomal dominant inheritance. We believe that this condition of blepharophimosis, ptosis, epicanthus inversus, telecanthus, amblyopia, and menstrual abnormality found in our patients may be rare, and that the menstrual abnormality in these patients may be associated with ovarial failure.

Adult↗

PubMed1994

Dopamine-induced protection of striatal neurons against kainate receptor-mediated glutamate cytotoxicity in vitro.

The effects of dopamine on glutamate-induced cytotoxicity were examined using the primary cultures of rat striatal neurons. Cell viability was significantly reduced by exposure of cultures to glutamate or kainate for 24 h. In contrast, similar application of N-methyl-D-aspartate (NMDA) or alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate (AMPA) did not induce cytotoxicity. Kainate-induced cytotoxicity was significantly inhibited by kynurenate but not by MK-801. Dopamine at concentrations of 1-100 microM dose-dependently reduced kainate-induced cytotoxicity. Forskolin also significantly reduced kainate cytotoxicity. The neuroprotective effect of dopamine was antagonized by SCH 23390, a D1 receptor antagonist, but not by domperidone, a D2 receptor antagonist. Moreover, kainate-induced cytotoxicity was prevented by SKF 38393, a D1 receptor agonist, or forskolin but not by quinpirole, a D2 receptor agonist. The patch clamp study revealed that the same striatal neurons responded to both kainate and NMDA. During voltage clamp recording, neither kainate-induced currents nor NMDA-induced currents were affected by dopamine. Moreover, dopamine did not affect glutamate- or kainate-induced Ca2+ influx measured with fura-2. These findings indicate that dopamine prevents kainate receptor-mediated cytotoxicity without affecting the kainate receptor activities and intracellular Ca2+ movement. Dopamine-induced neuroprotection may be mediated by an increased intracellular cAMP formed following activation of D1 receptors.

Animals↗

PubMed1994

Structural model of the ATP-binding domain of the F1-beta subunit based on analogy to the RecA protein.

In contrast to the previous topological model of the ATP binding domain of the F1-ATPase beta subunit based on analogies to those of ras p21 and adenylate kinase, a more consistent model can be constructed with the known structure of the recA protein as a reference. The secondary structure of the F1-ATPase beta subunit predicted from the primary structure agrees well with that of the recA protein. The topology includes a repetitive beta alpha c beta alpha beta alpha beta alpha beta structure where all beta strands are parallel and surround the central alpha c helix above which bound ATP is located. Several residues thought to be located at catalytic site as reported in genetic and chemical labeling work can be consistently positioned in this model.

Adenosine Triphosphate↗

PubMed1994

Spatial precision of a catalytic carboxylate of F1-ATPase beta subunit probed by introducing different carboxylate-containing side chains.

Combining mutation and chemical modification, we have introduced Asp, Gln, Cys, S-carboxymethylcysteine (Cax) and S-carbamoylmethylcysteine (Cam) into the positions of Glu190 and Glu201 of the beta subunit of F1-ATPase from the thermophilic Bacillus PS3. The steady-state ATPase activities of alpha 3 beta 3 gamma complexes containing these changed beta subunits were 12% (E190Cax), 7% (E190D), 3% (E190Cam), < 1% (E190C), < 1% (E190Q), and 73% (E201D), 40% (E201Cax), 25% (E201C), 20% (E201Q), 4% (E201Cam), of that of that of the wild-type alpha 3 beta 3 gamma complex. For the complexes containing E190C or E190Q, even the ability of single-site catalysis was lost. Thus, the presence of a carboxylate at 190 (but not at 201) is absolutely required for catalysis and its spatial precision is very strict. Analysis of inactivation of the complexes by dicyclohexylcarbodiimide suggests that Glu190 and Glu201 are interacting in the F1-ATPase.

Amides↗

PubMed1994

5-HT1A receptor-mediated inhibition of lateral vestibular nucleus neurons projecting to the abducens nucleus.

Electrophysiological studies were performed using cats anesthetized with alpha-chloralose, to elucidate the 5-hydroxytryptamine (5-HT) receptor subtypes involved in the 5-HT-induced inhibition of the lateral vestibular nucleus (LVN) neurons projecting to or through the abducens nucleus. The effects of 5-HT receptor subtype agonists and antagonist were examined in polysynaptic neurons activated by stimulation of the ipsilateral abducens nucleus (IAN) antidromically, since these neurons are sensitive to 5-HT as shown in our previous study. Iontophoretic application of 5-HT and 8-hydroxy-2-(di-n-propylamino)tetrain (8-OH-DPAT), a selective 5-HT1A agonist, inhibited orthodromic spikes elicited by vestibular nerve stimulation in the majority of polysynaptic neurons activated by stimulation of ipsilateral IAN antidromically. There was a good correlation between the effects of 5-HT and 8-OH-DPAT. Iontophoretically applied 5-HT and 8-OH-DPAT also inhibited glutamate-induced firing in these neurons. Simultaneous application of 1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl]piperazine (NAN-190), a 5-HT1A agonist/antagonist, significantly antagonized the 8-OH-DPAT-induced inhibition of glutamate-induced firing, although NAN-190 alone also caused weak suppression of glutamate-induced firing. Microiontophoretically applied 1-(3-chlorophenyl)piperazine (mCPP), a 5-HT1B agonist inhibited the orthodromic spike elicited by vestibular nerve stimulation and glutamate-induced firing in only a small number of the LVN neurons. 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI), a 5-HT2 agonist, rarely affected these neurons. We postulate that postsynaptically located 5-HT1A receptors are mainly involved in the 5-HT-induced inhibition of polysynaptic neurons projecting in the region of the IAN.

8-Hydroxy-2-(di-n-propylamino)tetralin↗

PubMed1994

Age-related changes in activities and localizations of cathepsins D, E, B, and L in the rat brain tissues.

Altered cellular levels and localizations of four distinct intracellular proteinases, cathepsins D, E, B, and L, with aging were studied in various rat brain tissues by enzymatic and immunohistochemical methods using discriminative antibodies specific for each enzyme. With regard to two aspartic proteinases, cathepsin E was barely detectable in all the brain tissues of young adult rats, including the cerebral cortex, the hippocampus, the neostriatum, and the cerebellum, whereas cathepsin D was ubiquitously found in these tissues. Two cysteine proteinases, cathepsins B and L, also existed in these tissues of young rats at the relatively high levels of activities. In aged rats, the cathepsin D levels in all of the brain tissues examined were about twice those of young rats. Cathepsin E was markedly increased in the cerebral cortex and neostriatum of aged rats, but not in the other tissues. The levels of cathepsin B were also increased significantly in the neostriatum of aged rats, but not significantly in the other tissues. In contrast, the activity levels of cathepsin L were strikingly decreased in all the brain tissues of aged rats. At the light microscopic level, the increased immunoreactivity of cathepsins D and E in the brain tissues of aged rats was eminent in both the neurons and the glial cells. By double-immunostaining technique, the cathepsin D-positive glial cells were mainly associated with reactive astrocytes, whereas the cathepsin E-positive glial cells were largely reactive microglial cells. Western blot analyses revealed that the molecular forms of cathepsins D and E increasingly expressed in the cerebral cortex of aged rats were similar to those of the respective normal mature enzymes. The increased immunoreactivity of cathepsin B in the neostriatum of aged rats was also found in both the neurons and the glial cells. Despite the marked decrease of the cathepsin L activity in various brain tissues of aged rats, the immunostaining for this enzyme was not significantly changed, indicating the occurrence of the catalytically inactive form of the enzyme in these tissues. These results suggest that the increased levels of cathepsins D, E, and B and the decrease in cathepsin L activity in brain regions of aged rats are related to both the neuronal degeneration and the reactivation of glial cells during the normal aging process of the brain.

Aging↗

PubMed1994

Excitation by talipexole, a dopamine D2 agonist, of caudate nucleus neurons activated by nigral stimulation.

An electrophysiological study using cats anesthetized with alpha-chloralose was performed to elucidate whether or not talipexole (B-HT 920 CL2: 6-allyl-2-amino -5, 6, 7, 8-tetrahydro-4H-thiazolo [4, 5 -d] -azepine-dihydrochroride), a dopamine D2 agonist, acts on postsynaptic dopamine receptors in the caudate nucleus (CN) neurons receiving excitatory input from the pars compacta of substantia nigra (SN). Extracellular neuron activities were recorded in the CN using a glass-insulated silver wire microelectrode attached along a seven-barreled micropipette, each of which was filled with talipexole, quinpirole (dopamine D2 agonist), domperidone (dopamine D2 antagonist), glutamate and 2M NaCl. These drugs were microiontophoretically applied to the immediate vicinity of the target neuron. In the same neurons in which the spikes elicited by the SN stimulation were blocked by microiontophoretically applied domperidone, microiontophoretic application of talipexole and quinpirole induced a dose-dependent increase in spontaneous firing. This increase in firing by talipexole and quinpirole was blocked during simultaneous application of domperidone, although glutamate-induced firing remained unaffected by domperidone. In the CN neurons, in which the SN stimulation-induced spikes were not blocked by domperidone, spontaneous firing was not affected by talipexole or quinpirole. These findings suggest that talipexole activates CN neurons receiving a dopaminergic input from SN via D2 receptors, as does quinpirole.

Action Potentials↗

PubMed1994

Isolation, characterization and epistasis of fluoride-resistant mutants of Caenorhabditis elegans.

We have isolated 13 fluoride-resistant mutants of the nematode Caenorhabditis elegans. All the mutations are recessive and mapped to five genes. Mutants in three of the genes (class 1 genes: flr-1 X, flr-3 IV, and flr-4 X) are resistant to 400 micrograms/ml NaF. Furthermore, they grow twice as slowly as and have smaller brood size than wild-type worms even in the absence of fluoride ion. In contrast, mutants in the other two genes (class 2 genes: flr-2 V and flr-5 V) are only partially resistant to 400 micrograms/ml NaF, and they have almost normal growth rates and brood sizes in the absence of fluoride ion. Studies on the phenotypes of double mutants showed that class 2 mutations are epistatic to class 1 mutations concerning growth rate and brood size but hypostatic with respect to fluoride resistance. We propose two models that can explain the epistasis. Since fluoride ion depletes calcium ion, inhibits some protein phosphatases and activates trimeric G-proteins, studies on these mutants may lead to discovery of a new signal transduction system that controls the growth of C. elegans.

Animals↗

PubMed1994

Tyr-341 of the beta subunit is a major Km-determining residue of TF1-ATPase: parallel effect of its mutations on Kd(ATP) of the beta subunit and on Km(ATP) of the alpha 3 beta 3 gamma complex.

Residue Tyr-341 of the F1-ATPase beta subunit from a thermophilic Bacillus strain, PS3, was mutagenized to leucine, cysteine or alanine. Each of the mutated beta subunits was isolated and its affinity for ATP-Mg was examined by means of difference circular dichroism and differential titration calorimetry. The Kd values for ATP-Mg obtained were: beta Y341 (wild type), 0.015 mM; beta Y341L, 0.7 mM; beta Y341C and beta Y341A, > 3 mM. All the mutant beta subunits could be reconstituted into the alpha 3 beta 3 gamma complex with alpha and gamma subunits. The alpha 3 beta (mutant)3 gamma complexes hydrolyzed ATP with apparent Vmax values larger than that of the alpha 3 beta (WILD)3 gamma complex. The apparent Km values of the alpha 3 beta (mutant)3 gamma complexes increased in parallel with the Kd values for ATP-Mg of the isolated mutant beta subunits. These results indicate that residue beta Y341 is directly involved in the catalytic ATP-Mg binding and is a major Km-determining residue of F1-ATPase.

Adenosine Triphosphate↗

PubMed1994

Genetic variants of ribosomal DNA and mitochondrial DNA between swamp and river buffaloes.

To clarify the genetic relationship between Swamp and River buffaloes, the restriction fragment length polymorphisms (RFLPs) of nuclear genomic ribosomal DNA (rDNA) and cytoplasmic mitochondrial DNA (mtDNA) were analysed. Blood or liver samples from 73 Swamp and three River buffaloes were collected in East and South-east Asian countries. DNA samples from cattle, goats and sheep were used for comparisons. The analysis of rDNA allowed water buffaloes, cattle, goats and sheep to be characterized by four distinct repeat-types. However, swamp and river buffaloes showed the same repeat-type. Divergence of water buffalo and cattle is considered to have occurred approximately four to six million years ago. The RFLPs for mtDNA divided water buffaloes into three haplotypes, swamp-1, swamp-2 and river types. Swamp-1 accounted for 91% of all swamp buffaloes while swamp-2 was observed only in water buffaloes from Thailand (9%). All river buffaloes were of the same haplotype. No differences were observed between swamp and river buffaloes at the rDNA level. In contrast, a few distinct differences between them were found at the mtDNA level. Therefore, mtDNA polymorphisms provide an adequate means for classifying water buffaloes into either swamp or river buffaloes.

Animals↗

PubMed1994

Transrectal ultrasonography of the prostate and seminal vesicles with hemospermia.

Transrectal ultrasonography was performed in 46 patients with hemospermia. Abnormal findings in the prostate and seminal vesicles, including prostatic stones, benign prostatic hyperplasia, prostatitis, and dilatation and calculi of the seminal vesicles, were observed in 34 patients (73.9%). However, no malignant lesions were found in the prostate or seminal vesicles. Transrectal ultrasonography was a useful and noninvasive procedure to investigate the causes of hemospermia. Furthermore, transrectal ultrasonography could demonstrate latent diseases and exclude malignancy of the prostate and seminal vesicle in patients with hemospermia.

Blood↗

PubMed1994

Inhibitory effects of 7-OH-DPAT, dopamine D3-receptor agonist, on nucleus accumbens neurons.

Effects of 7-hydroxy-2-(N,N-di-n-propylamino)tetralin (7-OH-DPAT), a dopamine D3-receptor agonist, on neuronal activities of the nucleus accumbens (Acc) were examined in chloral hydrate-anesthetized rats. Spikes elicited by stimulation of the parafascicular nucleus were dose-dependently inhibited by microiontophoretic application of dopamine and 7-OH-DPAT. Glutamate-induced firing was also inhibited by these drugs. These findings suggest that D3 receptors are also involved in the postsynaptic inhibition of Acc neuron by dopamine.

Animals↗

PubMed1994

[The regional skin temperature of hand under different clothing conditions].

The change in the regional skin temperature of hand was investigated under two different clothing conditions. The skin temperatures at six points on the palm, dorsum, and middle finger of the hand, respectively, were measured by using thermister thermometers simultaneously. The measurements were performed in a climate chamber conditioned at 20 degrees C and 65% R.H.. The subjects were 10 healthy females aged between 20 and 24 years. Five out of the 10 subjects wore light clothing (ca. 0.36 clo) and the others heavy clothing (ca. 0.75 clo). They first rested sitting on a chair for 30 min in the climate chamber before the onset of measurement. The results are as follows: 1) The skin temperature of the palm was higher than that of the other parts. Data were rather scattered in the case of the middle finger. 2) The skin temperature of the middle finger dropped to about 3 degrees C within 20 min after the start of measurement. 3) The skin temperature of the middle finger was affected by the clothing condition. We imagine that the skin temperature of the middle finger closely relates to arteriovenous anastomoses (AVA) located in the finger. Clothing probably plays an important role in controlling the blood flow of the AVA vessels, and consequently the skin temperature of the middle finger changes more sensitively than other parts of the hand.

Adult↗