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Biomedical subjects

N Hashimoto

Publications and source records attributed to N Hashimoto.

At least 73 records · Page 4Linked to original sources

Memory development in early childhood: encoding process in a spatial task.

A new kind of spatial task was devised to provide a description of the development of mnemonic strategy in early childhood. Five kinds of vertical arrays of drawings differing only in left-right orientation were presented one by one. Children at ages 5, 6, 7, and 9 years were asked to reconstruct the model. Most of the preschoolers succeeded only with those arrays in which drawings in the same orientation were juxtaposed. Memory for the most complicated array was not accurate enough until age 9. During the study, the oldest children usually verbalized the orientations as a sequence or the positions of the drawings in each orientation distinctively. This was interpreted as indicating that only the oldest children executed the sophisticated encoding strategies that integrate information on the orientation and position. Analysis of children's answers to the question about how to memorize revealed that awareness of using a strategy emerged at age 7 and grew clear by age 9.

Attention

Cervical spinal epidural hematoma with spontaneous remission.

Spinal epidural hematoma (SEH) is comparatively rare. In most cases, urgent surgical decompression is necessary. Several reports have described spontaneous remission of SEH. The authors present a rare case of spontaneous resolution of cervical SEH.

Epidural Space

Naturally occurring anti-interferon-alpha 2a antibodies in patients with acute viral hepatitis.

The occurrence of antibodies against recombinant human interferon-alpha 2a (IFN-alpha 2a) in patients with acute viral hepatitis (AVH) was examined by ELISA. Naturally occurring IgG anti-IFN-alpha 2a were found in 50% of patients with type A, 50% of those with type B and in 8.3% of those with non-A, non-B AVH. The corresponding frequencies of IgM antibodies were 80%, 30% and 33.3%, respectively. IgM anti-IFN-alpha 2a were found more frequently in patients with AVH type A than in normal control subjects (P less than 0.01). Anti-IFN-alpha 2a were detectable at the highest frequency 3 weeks after acute onset and then became negative. An absorption experiment revealed that IgM anti-IFN-alpha 2a did not cross-react with recombinant human IFN-alpha 2b. Immunoblotting analysis confirmed the binding of antibodies to IFN-alpha 2a. Sera positive for IgG and/or IgM anti-IFN-alpha 2a were unable to neutralize IFN-alpha 2a. The appearance of anti-IFN-alpha 2a was not correlated with disease severity. There was no evidence to suggest that anti-IFN-alpha 2a impaired the elimination of hepatitis virus. This is the first study to demonstrate the occurrence of anti-IFN-alpha 2a in patients with AVH. Detection of anti-IFN-alpha 2a may be useful for clarifying any underlying immune events in various diseases.

Acute Disease

An ultrastructural study of vulval myofibroblastoma in a cow.

A case of myofibroblastoma in a 3-year-old Japanese Black cow is described. Raised tumours which formed in the anus and in the labium and vestibulum of the vulva during pregnancy were excised surgically. The latter two tumours had dense growth of slender spindle cells beneath the epithelium, and fibrous connective tissue at the periphery. The anal tumour consisted of abundant collagen and sparse numbers of spindle cells. Proliferating cells contained moderate amounts of thin filaments with focal densities as well as well-developed rough endoplasmic reticulum and Golgi apparatus, and desmosome-like structures were found between the cells. These cells were distinguishable from leiomyoma cells containing abundant thin filaments and poorly-developed organelles. In the neoplastic lesions, there was an infiltration of many lymphocytes, plasma cells and macrophages.

Animals

Renal lesions in rats infected with Rattus serotype hantavirus (SR-11 strain).

Hemorrhagic fever with renal syndrome (HFRS) virus, strain SR-11 (SR) was inoculated intraperitoneally into specific-pathogen-free (SPF) newborn rats, from which the kidney lesions were examined pathologically. The infected rats revealed proteinuria on and after 16 days postinoculation (PI). Histologically, the epithelial cells of the renal tubules showed mild vacuolar and granular degeneration with cytoplasmic inclusion bodies (CIB) on and after 16 days PI. Ultrastructurally, a decrease in number of mitochondria and endocytic vesicles was recognized in the epithelial cells of the proximal renal tubules. Occasionally, both the proximal and distal renal tubular cells had CIB near well-developed Golgi apparatus on and after 13 days PI. Immunohistochemically, CIB were positive for anti-SR nucleocapsid antibody, but negative for anti-SR envelope protein antibody. From the results obtained here, it was concluded that the proteinuria in rats infected with HFRS virus resulted from an insufficiency of reabsorption in the proximal renal tubules, and that CIB consisted of the viral nucleocapsid protein.

Animals

Pathological studies on central nervous tissues of rats infected with Rattus serotype hantavirus (SR-11 strain).

Newborn rats inoculated intraperitoneally with a hantavirus strain (SR-11) developed neurological signs such as ataxia and limb paralysis. The main histological lesions were scattered and multiple neuronal degeneration and necrosis with eosinophilic cytoplasmic inclusion bodies (CIB) in the brain, spinal cord and ganglia. Immunohistochemically, the viral antigen was detected in neurons, capillary endothelial and glial cells throughout the nervous tissue and CIB were identified as consisting of hantaviral antigen (nucleocapsid protein). Ultrastructurally, CIB in the neurons consisted of an accumulation of granular or filamentous materials, or both. They were seen near a well-developed Golgi apparatus and associated with well-developed rough endoplasmic reticulum and increased numbers of ribosomes. The present results suggested that this virus strain was highly infective in neurons of the newborn rats and that excess production of viral antigen which accumulated as CIB resulted in the neuronal changes.

Animals

Detection of burst-promoting activity in spleens of myeloproliferative sarcoma virus-infected mice using serum-free cultures.

Myeloproliferative syndrome was induced in adult DBA/2 mice by inoculation with myeloproliferative sarcoma virus (MPSV) and Friend murine leukemia virus (F-MuLV) as a helper virus. On day 26 after infection, the spleen weighed a maximum of 2.0 g (about 30 times the control weight). Assay of multipotent stem cells in vitro showed that the more enlarged spleens contained an increased number and concentration of mixed colony-forming units (CFU-mix) (at maximum, 11 times higher than the control). When the supernatant of cultured spleen cells was added to a serum-free bone marrow cell culture with or without erythropoietin (Epo) for detection of burst-promoting activity (BPA), it enhanced erythroid mixed colony (E-mix) formation only in the presence of Epo (p less than 0.05). Even when addition of Epo was delayed, it still induced a significant number of E-mix (p less than 0.05). These findings rule out a mimic effect of Epo resembling BPA and indicate the presence of BPA in the spleen. The culture supernatant also supported the proliferation of interleukin 3 (IL-3)-dependent 32Dcl cells. Therefore, although purification of the BPA substance has not yet been accomplished, BPA in the supernatant seems to depend on the presence of IL-3, which is known to be one of the factors stimulating multipotent hemopoietic stem cells. The presence of BPA- or CFU-mix-stimulating activity in the spleen after infection might be responsible for the development of panmyelosis, which is a characteristic of MPSV-induced myeloproliferative syndrome.

Animals

Serological assessment of chlamydial infection in the koala by a slide EIA technique.

A rapid and simplified slide enzyme immunosorbent assay (EIA) was developed for the diagnosis of chlamydial infection in the koala. HeLa 229 cells infected with koala strain Chlamydia psittaci were fixed on the surface of multiwell slides and used as the antigen. The assay consisted of first reacting koala antiserum with the fixed C psittaci antigen, followed by reaction with biotinylated rabbit anti-koala IgG, ABC reagent and substrate. The chlamydial EIA antibody titres obtained were compared with those of a complement fixation (CF) test using koala strain C psittaci as antigen. Of 35 koala sera tested, 16 CF positive sera (greater than or equal to 1:8) also had a positive titre (greater than or equal to 1:200) in the slide EIA test (sensitivity 93.8%, 15/16). Nineteen CF negative sera were also negative in the slide EIA (specificity 100%, 19/19). Sixty-eight samples of koala blood were collected by ear-prick using a sampling paper method and were assayed by both tests. Sensitivity of the slide EIA was 100% (15/15) and specificity of the test was 96.2% (51/53). To simplify the slide EIA for use as a practical screening test, a 3-point serum dilution series (1:100, 1:200, 1:400) was used. This 3-point slide EIA was compared with the CF test using sheep strain chlamydial antigen. Thirty-nine sera were assayed by both tests. The sensitivity of the 3-point method was 85.7% (6/7) and the specificity was 71.9% (23/32) as compared with the sheep antigen CF test.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals

Kinetic studies on the appearance of antigens of Chlamydia psittaci during its developmental cycle.

The kinetics of the antigen production of Chlamydia psittaci strains Izawa-1 and Pigeon-1041 (P-1041) was examined every 6 hr after infection up to 48 hr, by the indirect immunofluorescent antibody technique using monoclonal antibodies (MAbs). All three genus-specific antigenic determinants on lipopolysaccharide (LPS) appeared during the whole growth cycle. Antigenic determinants on proteins were, on the other hand, detected at various time periods from the early to the late stages of infection. However, a cross-reactive antigenic determinant on protein recognized by a MAb 3E9 was also detected during the whole growth cycle, similar to that on LPS. The time of appearance of common antigenic determinants on proteins of Izawa-1 and P-1041 was examined using cross-reactive MAbs, and it varied depending on heterologous and homologous MAbs. From the relationship between the detection of antigenic determinants and the morphological changes of chlamydial particles revealed by electron microscopy during the growth cycle, the antigenic determinants on proteins of Chlamydia psittaci were divided into two groups; one was specific to the elementary body and the other was coexisting in both the elementary body and the reticulate body.

Animals

Cerebral blood flow patterns at major vessel bifurcations and aneurysms in rats.

Cerebral arterial bifurcations in rats were treated to induce cerebral aneurysms experimentally, and flow patterns of latex particles introduced under a constant flow rate were analyzed with a 16-mm cine-camera and videocassette recorder. Cerebral aneurysms were produced by ligating one common carotid artery, inducing experimental hypertension, and feeding the animals beta-aminopropionitrile. After perfusion and fixation, samples of cerebral arterial bifurcations with shallow invaginations and with small aneurysms were obtained and used for analysis. Bifurcations in rats without experimental treatment were used as control specimens. Flow studies in the control bifurcations showed that the apical intimal pad, not the apex itself, acted as the flow divider. Small particles tended to accumulate at the region just distal to the apical intimal pad, where the initial aneurysmal changes are known to occur. This indicates stagnation of flow at that site. In the bifurcations with shallow invaginations and small aneurysms, a marked pressure gradient was present at the proximal end of the aneurysm orifice. A tendency for stagnation of small particles near the aneurysm wall was also observed. The wall shear stress was highest at the distal end of the aneurysmal orifice, which may be responsible for the development of these lesions.

Animals

Susceptibility of laboratory and wild rodents to Rattus or Apodemus-type hantaviruses.

Adult Wistar rats (Rattus norvegicus), Apodemus agrarius, Meriones unguiculatus, Clethrionomys rufocanus, and Apodemus argenteus were inoculated with Rattus-type (SR-11, KI-262, and TB-314) or Apodemus-type (Hantaan 76-118) hantaviruses. Production of serum antibody to the inoculated virus (IAHA titres of 1:32 to 1:4 096) was obsersved in all rodent species 10 weeks after virus inoculation. Rattus-type virus was detected in some organs of all the rodent species employed except of Apodemus agrarius. Apodemus-type virus was found only in some organs of Apodemus agrarius. Newborn Wistar rats induced antibody in high titres to both Rattus- and Apodemus-type hantaviruses. Rattus-type virus was detected in all the organs examined for up to 6 weeks after inoculation, whereas Apodemus-type virus disappeared from all organs except of brain and lung tissues. The virulence of the three Rattus-type viruses to newborn rats was different. These findings indicate that the susceptibility of rodents may vary depending on the combination of rodent species and virus strains; they also suggest that the various species of rodents may be the reservoir animals of hantavirus infection in nature.

Animals

Nucleotide sequence of a gene encoding a new genus specific protein of Chlamydia psittaci.

DNA fragment No. 13 from the C. psittaci pigeon strain, has been cloned in the plasmid pUC19. Hybridization analysis revealed that the fragment maintained a chlamydial common sequence. Furthermore, nucleotide sequencing identified two partial open reading frames (ORF), 675b. p. and 530b. p. Expression of ORFs revealed that the second ORF encoded 25KD polypeptide, whereas the first ORF did not produce any antigenic product. The 25KD beta-galactosidase fusion protein reacted strongly with chlamydia-specific antibodies elicited against a number of different chlamydial strains. Gene Bank analysis showed that this cloned gene is not highly homologous with chlamydia or other organisms for which nucleotide sequences have already been published. This 25KD polypeptide may be an additional genus-specific antigen of Chlamydiae.

Amino Acid Sequence

Characterization of DNA fragment from Chlamydia psittaci avian strain which shows high homology with hypB gene of Chlamydia.

A study was performed to characterize DNA fragment No. 17 of C. psittaci strain P-1041 which encoded 42 KD beta-galactosidase fusion protein with type-specific antigenicity. Sequence determination identified a partial open reading frame that spanned about 1,200b. p. nucleotides. Screening the literatures for the nucleotide and deduced amino acid sequences revealed extensive similarity between the DNA fragment of P-1041 and two chlamydial hypB genes. This DNA showed 91.5% homology with C. psittaci GPIC hypB gene in nucleotide sequence and 96.4% homology in deduced amino acid sequence. The hypB gene of C. trachomatis serovar A and the P-1041 DNA fragment showed 81.2% and 91.3% homology in nucleotide and amino acid sequences, respectively. Dot enzyme-linked immunosorbent assay, for the products of deleted DNA fragments defined the coding region for type-specific antigenic polypeptide. In addition, the P-1041 DNA fragment carried a sequence highly homologous (greater than 49%) with other bacterial and plant genes called chaperonin which responds to various stress in cells. From these results, the P-1041 DNA fragment was found to be a part of hypB gene and to encode the region critical for type-specific antigenicity.

Amino Acid Sequence

Accumulation of quinolinic acid in uremic serum and its removal by hemodialysis.

Quinolinic acid was first identified in uremic serum by use of gas chromatography/mass spectrometry. Quantification by selected ion monitoring revealed that the serum concentration of quinolinic acid was markedly increased in chronic hemodialysis patients, and that the acid could be removed by conventional hemodialysis. The serum concentration of quinolinic acid was weakly but significantly correlated with the serum uric acid concentration. Accumulation of quinolinic acid in uremic blood may be involved in the pathogenesis of anemia, suppressed immune system, and uremic encephalopathy.

Adult

[A study of the determination of serum fucose concentrations].

We examined the biochemical properties of reaction products during the procedure for serum fucose determination (Dische & Shettles). The optical density at 396 nm (OD396) of the reaction products increased linearly with the increment of fucose concentrations, and was stable for at least 210-240 min at room temperature. The reaction products were destroyed with the addition of distilled water. Sephadex G-200 gel chromatography of the mixed serum samples revealed a single peak of fucose in the void volume fractions. Of interest was the presence of trace amounts of fucose detected in the low-molecular weight fractions less than 66,000, suggesting the presence of free fucose in the serum. Based on these observations, the method for serum fucose determination was modified so it was possible to use 100 microliters of the serum sample. The mean serum fucose concentration, measured by this modified method, was 561.0 +/- 191.1 mumol/l (9.1 +/- 3.1 mg/dl) in normal healthy children. In patients with idiopathic nephrotic syndrome, the values were significantly higher both at relapse and in remission than those in normal healthy children.

Chemical Fractionation

Trolox protects rat hepatocytes against oxyradical damage and the ischemic rat liver from reperfusion injury.

Trolox, a hydrophilic analog of vitamin E, was reported to scavenge peroxyl radicals from artificial systems better than its parent compound. Here we examined the possible cytoprotective effect of Trolox in cultured hepatocytes and in the rat liver. In cultured rat hepatocytes, 0.5 to 16 mmol/L Trolox (with optimum between 1 to 2 mmol/L) was observed to prolong the survival of cells exposed to oxyradicals generated with xanthine oxidase-hypoxanthine. The protection by 1 mmol/L Trolox surpassed that provided by either ascorbate, mannitol, superoxide dismutase and/or catalase--each at a level giving its maximal protection in the same system. In both a global and partial model of hepatic ischemia-reperfusion in rats, infusion of Trolox (7.5 to 10 mumol/kg body weight) just before reflow reduced by greater than 80% the liver necrosis sustained in untreated (no Trolox) control rats. Such organ salvage was apparently accompanied by approximately 50% reduction in the amount of hepatic conjugated dienes, which were quantified by a highly specific radiochemical assay. Since conjugated dienes are presumed to be good "markers" of oxyradical damage, our data may have provided a semiquantitative link between free radical-induced necrosis and its chemical imprint in vivo. The data also indicated a relatively rapid and potent antioxidant-like action by Trolox on rat hepatocytes and on the postischemic reperfused rat liver.

Animals