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Biomedical subjects

A Sato

Publications and source records attributed to A Sato.

At least 361 records · Page 20Linked to original sources
PubMed1997

Mapping of mhc class I and class II regions to different linkage groups in the zebrafish, Danio rerio.

The mammalian major histocompatibility complex (Mhc) consists of three closely linked regions, I, II, and III, occupying a single chromosomal segment. The class I loci in region I and the class II loci in region II are related in their structure, function, and evolution. Region III, which is intercalated between regions I and II, contains loci unrelated to the class I and II loci, and to one another. There are indications that a similar Mhc organization exists in birds and amphibians. Here, we demonstrate that in the zebrafish (Danio rerio), a representative of the teleost fishes, the class II loci are divided between two linkage groups which are distinct from the linkage group containing the class I loci. The beta2-microglobulin-encoding gene is loosely linked to one of the class II loci. The gene coding for complement factor B, which is one of the region III genes in mammals, is linked neither to the class I nor to the class II loci in the zebrafish. These results, combined with preliminary data suggesting that the class I and class II regions in another order of teleost fish are also in different linkage groups, indicate that close linkage of the two regions is not necessary either for regulation of expression or for co-evolution of the class I and class II loci. They also raise the question of whether linkage of the class I and class II loci in tetrapods is a primitive or derived character.

Animals↗
PubMed1997

Evidence for convergent evolution of A and B blood group antigens in primates.

To determine whether convergent or trans-specific evolution is responsible for the persistence of the ABO polymorphism in apes, we have sequenced segments of introns 5 and 6 of the ABO gene. Four substitutions and one insertion or deletion group human A, B, and O alleles together, separate from their chimpanzee A and gorilla B counterparts. No shared substitutions support a trans-species mode of evolution for any of the alleles examined. We conclude that the A and B antigens of the chimpanzee and gorilla, respectively, have arisen by convergent evolution. Phylogenetic analysis suggests that the human A and B alleles are ancient, having diverged at least 3 million years ago. These alleles must have therefore been trans-specifically inherited within the genus Homo.

ABO Blood-Group System↗
PubMed1997

Separation of multiple yellow fluorescent lipofuscin components in rat kidney and their characterization.

Yellow fluorescent lipofuscin deposited in rat kidney was extracted in an aqueous solution and characterized after separation. Centrifugal fractionation of the extract revealed that most of the yellow fluorescence was detected in the 105,000 x g-supernatant, and little in nuclei, cell debris, mitochondria, lysosomes, microsomes and plasma membrane. The yellow fluorescence in the supernatant was fractionated by gel filtration through Sephadex columns into 5 yellow fluorescent fractions A, B (B1, B2 and B3) and C showing the same fluorescence spectra with excitation maximum/emission maximum at 400/620 nm. The components in fraction A were converted into the smaller molecular-weight components in fraction B on treatment with 4 M urea or protease, suggesting that they were proteinaceous. The smallest molecular-weight fluorescent components in fraction C were adherent to solid cellulose materials. The fluorescent components in all the fractions were soluble in water and insoluble in chloroform-methanol, indicating that they were not lipidic materials. The fluorophores in these fractions were kept stable on borohydride treatment, but readily converted into non-fluorescent components on heavy-metal ion treatment. The characteristics of the yellow fluorescence in these fractions were quite different from those of bluish lipofuscin-like fluorophores that may be generated in tissues during lipid peroxidation.

Aging↗
PubMed1997

Failure of aged rats to accumulate eosinophils in allergic inflammation of the airway.

To investigate the effect of aging on the allergic airway response, we examined the bronchoconstrictive responses and cellular inflammatory changes in a rat model of bronchial asthma by evaluating young and old animals. Two different age groups of Brown-Norway rats, actively sensitized by injection of ovalbumin into the foot pads, were used: 7 to 8 weeks old (young group) and 100 to 120 weeks old (aged group). Both the aged and young rats produced on ovalbumin-specific IgE antibody and exhibited an immediate asthmatic response after exposure to ovalbumin, but the degree of specific IgE antibody was significantly higher in young rats. The young group showed a marked increase in the number of eosinophils and neutrophils in bronchoalveolar lavage fluid 2 days after exposure to ovalbumin, whereas no eosinophilia was seen in the aged group. To evaluate the mechanism of the decreased accumulation of eosinophils in aged rats, cells from popliteal lymph nodes from ovalbumin-sensitized rats were incubated with ovalbumin for 48 hours. Although eosinophil chemotactic activity, determined by a modified Boyden chamber method, was present in the supernatant of cultured lymph node cells from young rats, it was absent from those of aged rats. In vivo administration of anti-IL-5 monoclonal antibody revealed that one of the factors of eosinophil chemotactic activity was IL-5. Lymph node cells from aged rats tended to produce greater amounts of interferon-gamma than did those from young animals. Findings indicate that aged rats have a defect in eosinophil accumulation in sites exposed to antigen, probably because of an age-dependent alteration in T cells.

Aging↗
PubMed1997

Responses of adrenal function to stimulation of lumbar and thoracic interspinous tissues in the rat.

In urethane-anesthetized Wistar rats, the responses of adrenal sympathetic nerve activity and catecholamine secretion were measured following chemical stimulation of lumbar and thoracic interspinous tissues. Injection of normal saline into the lower lumbar or lower thoracic interspinous tissues produced no changes in adrenal sympathetic nerve activity or catecholamine secretion. On the other hand, the injection of capsaicin produced protracted increases in adrenal nerve activity and catecholamine secretion both in CNS-intact animals and in animals acutely spinalized at the Cl-2 level. Repetitive electrical stimulation of the medial branch of a lumbar primary dorsal ramus, the nerve which provides sensation to the lumbar interspinous tissues, produced A- and C-reflex discharges, mediated at the spinal and supraspinal levels, in the adrenal sympathetic nerve.

Adrenal Glands↗
PubMed1997

Prenatal determination of human platelet antigen type 4 by DNA amplification of amniotic fluid cells.

To predict a fetus at risk for neonatal alloimmune thrombocytopenia (NATP) caused by human platelet antigen (HPA)-4 incompatibility, we applied a sequence-specific polymerase chain reaction (PCR-SSP). We were able to determine the HPA-4 genotype of three infants at risk using amniotic fluid cells without the need for fetal blood sampling. The HPA-4 genotypes of amniotic fluid cells determined in this way were completely concordant with the genotype and phenotype of infants' venous blood samples obtained after delivery. Therefore, this technique is also convenient to a fetus at risk in the antenatal management of NATP induced by HPA-4 incompatibility.

Adult↗
PubMed1997

Epigallocatechin gallate-induced histamine release in patients with green tea-induced asthma.

BACKGROUND AND OBJECTIVE: Epigallocatechin gallate is the causative agent of green tea-induced asthma. To determine whether an IgE-mediated mechanism plays a pathogenetic role in this disorder, we measured histamine release after in vitro exposure to epigallocatechin gallate. METHODS: Subjects included eight patients (four men and four women) with green tea-induced asthma, who had been diagnosed by skin test and inhalation challenge, and eight controls (four asthmatic subjects with no previous exposure tea dust and four healthy volunteers). Heparinized whole blood samples were taken and incubated with epigallocatechin gallate at various concentrations (final concentration range, 0.003 to 300 micrograms/mL) for 30 minutes at 37 degrees C. After centrifugation, histamine was measured in the cell-free supernatants by radioimmunoassay. Histamine release was expressed as a percentage of total histamine. A result higher than 10% was considered positive. RESULTS: In one of the tea-sensitive patients, epigallocatechin gallate did not cause histamine release. Five of the other seven patients (71%) demonstrated a positive, dose-dependent histamine release to epigallocatechin gallate. In asthmatic and normal controls, histamine release was not observed at any epigallocatechin gallate concentration. Furthermore, a significant correlation was noted between the maximum percentage histamine release and the threshold epigallocatechin gallate concentration for intradermal skin testing. CONCLUSION: These results indicate that an IgE-mediated response is the basis for green tea-induced asthma.

Adult↗
PubMed1997

Design of stable biologically active recombinant lutropin analogs.

Glycoprotein hormones are noncovalent heterodimers comprised of a common alpha subunit and a hormone-specific beta subunit. Secretion and biologic action of these hormones are dependent on the formation of the heterodimer. The human LH beta subunit is unique among the other beta subunits in that it assembles inefficiently with the alpha subunit. To bypass this rate-limiting step, we constructed the LH single chains where the carboxy terminus of beta was fused to the amino terminus of alpha subunit through a linker. Compared to the human LH heterodimer, the extent of secretion was greater for the tethers although the rate was dependent on the nature of the linker. The LH single chains were biologically active even though there was loss of recognition by a LH-specific monoclonal antibody. This suggests that receptor binding of the single chains is not impaired by changes in the heterodimeric configuration resulting from tethering the subunits. In addition, single chains exhibited a remarkably greater in vitro stability than the heterodimer, implying that these analogs will be useful as diagnostic reagents and that their purification will be facilitated.

Animals↗
PubMed1997

Acute myelogenous leukaemia with t(8;21) translocation of normal cell origin in mosaic Down's syndrome with isochromosome 21q.

We report a 13-year-old girl with Down's syndrome (DS) having a mosaic karyotype of 46,XX/46,XX, -21,+i(21q), who developed acute myelogenous leukaemia (AML) (FAB M1). The t(8;21) translocation generating a AML1/MTG8 chimaeric gene of her blasts was demonstrated by cytogenetic analysis and reverse transcription-polymerase chain reaction. Interestingly, the leukaemic clone with t(8;21) did not have isochromosome 21q, indicating that the blasts were of normal cell origin. These findings suggest that, in older patients with DS, 21 trisomy cells have no greater predisposition to develop AML than normal karyotypic cells.

Adolescent↗
PubMed1997

High incidence of positive autoantibodies against thyroid peroxidase and thyroglobulin in patients with sarcoidosis.

OBJECTIVE: Although abnormalities of the humoral immune system, such as increased immunoglobulin production, are known in sarcoidosis, the relationship between sarcoidosis and autoimmune disorders in uncertain. We studied the incidence of thyroid autoantibodies and the prevalence of Hashimoto's thyroiditis in patients with sarcoidosis. PATIENTS AND MEASUREMENTS: Sixty-two patients with pulmonary sarcoidosis, diagnosed by a combination of clinical, radiographic and histological findings were studied. As controls, three groups of subjects aged 40 and over without a known history of thyroid disease (60 patients with pulmonary diseases other than sarcoidosis, 88 hospital employees and 82 company workers), were also analysed. Antibodies against thyroid peroxidase (TPO-Ab) and purified thyroglobulin (Tg-Ab) were measured by radioimmunoassay and antibodies against microsomal antigen (MCHA) and thyroglobulin (TGHA), by haemagglutination. RESULTS: Seventeen of 62 patients (27.4%) had either positive TPO-Ab or Tg-Ab or both. All the patients with positive thyroid autoantibodies were of middle or advanced age, and the incidence of positive TPO-Ab/Tg-Ab in patients with sarcoidosis aged 40 and over was 54.5% in males, 32.4% in females and 37.8% overall. The prevalence was significantly higher in males compared to age-matched control males (0-7.7% in the controls), and in female patients was twice that found in controls (11.8-16.3%). Seven patients had Hashimoto's thyroiditis, indicating that the prevalence was 11-3%, and much higher than that previously reported. CONCLUSIONS: The data show a remarkably high incidence of thyroid autoantibodies in patients of middle of advanced age with sarcoidosis, especially in males, and a higher prevalence of Hashimoto's thyroiditis than in previous reports.

Age Factors↗
PubMed1997

Effect of 6-fluoro-8-methoxy quinolone (AM-1155) against chronic airway infection with Pseudomonas aeruginosa in a rat model.

We studied the effect of AM-1155, a newly developed quinolone, against chronic airway infection with Pseudomonas aeruginosa using a previously described rat model. AM-1155 (25 mg/kg) or ciprofloxacin (25 mg/kg) or saline (controls) were injected s.c. for 14 days (from day 4 to day 17) after the inoculation of agar beads containing P. aeruginosa. The number of viable cells of intrapulmonary P. aeruginosa, histological findings of the lungs and immunoglobulin levels of serum and bronchoalveolar lavage fluid were examined in rats 11 and 18 days after the treatment. The findings indicated that the number of viable cells of P. aeruginosa in lungs was significantly decreased in the AM-1155- or ciprofloxacin-treated group compared with the non-treated control group. Histological examination in the non-treated control group showed hyperplasia of bronchus-associated lymphoid tissue as well as cellular infiltration in airways, but not prominently in the AM-1155- or ciprofloxacin-treated group. The IgG and IgA levels in serum and bronchoalveolar lavage fluid were significantly lower in the AM-1155- and ciprofloxacin-treated groups than in the control group. These in-vivo effects of AM-1155 were comparable to those of ciprofloxacin. These findings suggest that treatment with AM-1155 and ciprofloxacin suppressed excessive immune responses, preventing progression of airway damage in the chronic infectious state.

Animals↗
PubMed1997

Nucleotide sequence of the promoter region of chicken cytosolic phosphoenolpyruvate carboxykinase gene.

The nucleotide sequence of the promoter region and its flanking regions which span - 1855 to +2083 in the chicken cytosolic phosphoenolpyruvate carboxykinase gene was determined. The transcription initiation site was located at 119 nucleotides downstream of the previously reported chicken kidney transcription initiation site of this gene. The nucleotide sequences of exons 1, 2, and 3 were highly homologous to the corresponding exons of the rat gene. Homology of the sequence - 1 to - 500 to that of rat gene was 52% and most of the hormone-responsive sequences in rat gene, such as the glucocorticoid-responsive region, were not conserved in the chicken gene, in accord with the species-specific responsiveness to starvation. In contrast, in the region of - 1 to - 300, some sequence motifs conserved both in the chicken and rat genes were found at essentially the same positions in the promoters. Such sequence motifs included a cAMP-responsive element (CRE), a nuclear factor-1 (NF-1/CTF)-binding site, and a hepatocyte nuclear factor-1 (HNF-1)-binding site. Transient expression of the reporter luciferase gene ligated to the 3' end of this chicken sequence (-1855 to +7) was observed in a primary culture of chick hepatocytes when dibutyryl cyclic AMP was added to the culture medium.

Animals↗
PubMed1997

An abnormal sodium metabolism in Japanese patients with essential hypertension, judged by serum sodium distribution, renal function and the renin-aldosterone system.

OBJECTIVE: The role of the renin-aldosterone system and the ability of renal sodium reabsorption to facilitate pressure natriuresis were analyzed by using a sufficient number of Japanese patients with essential hypertension. METHODS: We studied 3222 normal Japanese subjects (610 in Kashiwa City Hospital and 2612 in Shinshu University Hospital), 741 Japanese patients with essential hypertension (256 in Kashiwa City Hospital and 485 in Shinshu University Hospital), 20 patients with aldosterone-producing adenomas and 11 patients with idiopathic hyperaldosteronism to determine the possible roles of sodium, renal function, and plasma aldosterone concentration (PAC) on blood pressure elevation. Inappropriate elevation of aldosterone levels [elevation of the aldosterone:plasma renin activity (PRA) ratio] was used to assess aldosterone action. RESULTS: The peak of the serum sodium distribution curve was approximately 2 mmol/l higher in the patients with essential hypertension than it was in controls. The prevalence of higher serum sodium concentrations (> or = 147 mmol/l) also was increased significantly hypertensive patients. Age-related deterioration of renal function did not explain the hypertension and abnormal sodium metabolism in the hypertensive patients. In stepwise regression analysis, the serum sodium concentration was related inversely to the PRA and positively to the PAC:PRA ratio. Although there was an inverse relationship between urinary sodium excretion (representing sodium intake) and the PRA, urinary sodium excretion proved not to be significant as a source of variation in the PAC or in the PAC:PRA ratio in the hypertensive patients. Although the PAC was within the normal range in patients with serum sodium concentrations of 147 mmol/l or more and an elevated PAC:PRA ratio, it was inappropriately high for the stimulus applied, as indicated by the PRA; this is similar to the situation with aldosterone-producing adenomas or idiopathic hyperaldosteronism. CONCLUSION: Serum sodium distribution patterns differed between normal subjects and patients with essential hypertension in this Japanese population. The deterioration of renal function and increased sodium intake did not explain this abnormal sodium metabolism. A higher serum sodium concentration is related to an elevated blood pressure, and, in some patients, an inappropriate elevation of plasma aldosterone levels. Of the Japanese hypertensive patients, 10-14% exhibited serum sodium concentrations of 147 mmol/l or more and inappropriate elevations of aldosterone level (suppressed PRA and normal aldosterone level). The defect in these patients presumably lies in the inappropriately high secretion of aldosterone.

Adult↗
PubMed1997

Application of image analysis and neural networks to the pathology diagnosis of intraductal proliferative lesions of the breast.

We studied whether a computer-assisted system using a combination of data collection by image analysis and analysis by neural networks can differentiate benign and malignant breast lesions. Forty-six intraductal lesions of the breast were studied by pathologists and by the computer-assisted system. Histological evaluation was performed independently by three pathologists, and the lesions were classified into pathologically malignant (n = 12), undetermined (n = 13), and benign (n = 21). Computerized nuclear image analysis was performed using the CAS200 (Cell Analysis Systems, Elmhurst, IL) system to obtain data on nuclear morphometric and textural features. A neural network was constructed using the morphometric and texture data obtained from teaching cases of malignant and benign lesions. Then data for unknown cases were classified by the constructed neural network into neural network-malignant (n = 11), -undetermined (n = 5), and -benign (n = 30). The agreement rate between the diagnosis by pathologists and judgment by the computer-assisted system was 75%, excluding pathologically undetermined lesions. There were four false-negative but no false-positive results. False-negative cases had nuclei that were quite different from those of the teaching cases. The agreement rate obtained using either morphometric data or texture data only was lower than that using a combination of both. Selection of appropriate teaching data and incorporation of both morphometric and textural parameters seemed important for obtaining more accurate results. The present data suggest that development of a computer-assisted histopathological diagnosis system for practical use may be possible.

Breast↗
PubMed1997

Effect of taurolithocholate-3-sulphate on biliary excretion of sulphobromophthalein and dibromosulphophthalein in the Eisai hyperbilirubinaemic rat.

We previously reported that biliary lithocholate-3-sulphate excretion was inhibited by dibromosulphophthalein, not by sulphobromophthalein in Eisai hyperbilirubinaemic rats (EHBR); instead its excretion was inhibited by both organic anions in control rats. In the present study, the effect of taurolithocholate-3-sulphate on the excretion of sulphobromophthalein and dibromosulphophthalein was studied in EHBR and control Sprague-Dawley rats. Taurolithocholate-3-sulfate infusion inhibited biliary excretion of sulphobromophthalein and dibromosulphophthalein in both EHBR and control rats. These findings indicate that in control rats biliary excretion of taurolithocholate-3-sulphate is mediated by a carrier common for both organic anions, and that in EHBR, in which the canalicular multispecific organic anion transporter is impaired, the excretory pathway for taurolithocholate-3-sulphate is also partly identical to that for both organic anions.

Animals↗
PubMed1997

A study of bronchus-associated lymphoid tissue in a rat model of chronic pulmonary infection with Pseudomonas aeruginosa.

The immunologic pathogenesis of conditions characterized by chronic pulmonary infections, such as diffuse panbronchiolitis and those associated with cystic fibrosis, had not been fully clarified. Organized lymphoid tissue along the airway has been termed bronchus-associated lymphoid tissue (BALT), and hyperplasia of BALT is frequently observed in chronic pulmonary infections in humans. To investigate the role of BALT, we intratracheally inoculated rats with Pseudomonas aeruginosa (PA) enmeshed in agar beads according to the method of Cash et al., thereby establishing a chronic pulmonary infection model. Histopathological examination of tissue from this rat model revealed the accumulation of lymphocytes and foamy cells around bronchioles. This finding corresponds to chronic bronchiolitis in humans. Hyperplasia of BALT was also observed. Immunohistochemical examination demonstrated that Ia+ cells, helper T cells, surface IgM-positive (sIgM+) cells and sIgA+ cells had gradually increased in BALT and the walls of peripheral airways during the period from day 4 to 7. The anti-PA IgA antibody titer in bronchoalveolar lavage fluid (BALF) was also elevated during this period. After day 21, non-helper T cells became predominant in tissue sections, and the numbers of various immunoglobulin-positive cells as well as the anti-PA IgA antibody titer in BALF were reduced. Histological examination revealed that the inflammatory findings had also diminished. The time course of changes in the various immune cells in BALT and the walls of peripheral airways, paralleled the reductions in anti-PA IgA antibody titers in BALF. Our findings suggest that hyperplastic BALT may be one source of the Ig producing cells which play an important role in the local immune response characteristic of chronic pulmonary infections.

Animals↗
PubMed1997

[A case of pseudomembranous enterocolitis which diagnosis was delayed in the outpatient clinic].

A 71-year-old male visited our hospital because of diarrhea. At first we suspected infectious colitis and levofloxacin (300 mg/day) was administered for four days. But the diarrhea continued, so performed a barium enema after about 3 weeks from onset. Round polyposis from the rectum to the sigmoid colon were found. Colonoscopy was suggested to the patient, but was rejected. However diarrhea continued and fever appeared. Ceftriaxone (1 g/day) and sparfloxacin (200 mg/day) were administered, but the symptoms increased. He was admitted about 6 weeks from onset, and the colonoscopy showed multiple round yellow-white pseudomembranes. Pseudomembranous enterocolitis diagnosed because Clostridium difficile and its toxin were positive in the feces. After oral administration of vancomycin (1.5 g/day) was started, the symptoms alleviated rapidly and disappearance of pseudomembrane was confirmed by colonoscopy.

Aged↗