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Biomedical subjects

Y Maeda

Publications and source records attributed to Y Maeda.

At least 19 recordsLinked to original sources
PubMed1992

Neutralizing activity of human antibodies against the structural protein of human T-cell lymphotropic virus type I.

We have identified and mapped the regions responsible for neutralization in the human T-cell leukemia virus type I (HTLV-I) structural proteins by using region-specific human antibodies derived from seropositive blood donors. We have obtained 18 kinds of region-specific antibody (2 in the p19 gag, 10 in the gp46 env and 6 in the gp21 env proteins) from seropositive human plasma by means of an affinity column coupled with the synthetic peptides corresponding to the antigenic regions of the HTLV-I structural proteins. These antibodies were highly specific in ELISA using synthetic peptides as an antigen. Subsequently, we examined the neutralizing activity expressed by the inhibition of virion-induced syncytium formation by region specific antibodies. Twelve of 16 antibodies derived from the env protein were able to inhibit syncytium formation induced by co-cultivation of 8C cells with HTLV-I antigen-positive T cells. The antibodies derived from the p19 gag protein and the seronegative plasma used as the control showed no significant activity. The sequences recognized by the 10 neutralizing antibodies were sites corresponding to amino acids 20 to 49, 89 to 115, 136 to 160, 175 to 199, 213 to 236, 235 to 254, 277 to 292, 332 to 352, 350 to 386, 382 to 403, 426 to 448 and 458 to 488 from the amino terminal of the env protein. These observations suggest that the neutralizing epitopes were widely distributed in the env proteins of HTLV-I.

Enzyme-Linked Immunosorbent Assay↗
PubMed1992

Sexual transmission of hepatitis C virus among female prostitutes and patients with sexually transmitted diseases in Fukuoka, Kyushu, Japan.

The authors investigated the prevalence of antibody to hepatitis C virus (anti-HCV) in 404 female prostitutes, 428 clinic patients with a history of at least one episode of sexually transmitted disease, and 8,944 blood donors who served as the controls. All subjects were Japanese, and all studies were carried out in Fukuoka, Kyushu, Japan, in 1989. The prevalence of anti-HCV was significantly higher in the prostitutes (6.2%), in the female patients with sexually transmitted diseases (6.1%), and in the male patients with sexually transmitted diseases (2.9%) than in the controls (1.5%). Prevalence of anti-HCV increased with age in prostitutes and in the controls. The prevalence of anti-HCV in those who had been involved in prostitution for 1 year or more (8.1%) was higher than in those who had been involved in prostitution for less than 1 year (1.4%), but the difference was not statistically significant. One of the 152 anti-HCV negative prostitutes seroconverted between 1 and 2 years later. Among the subjects with sexually transmitted diseases, patients with a history of at least one episode of syphilis had a significantly higher prevalence of anti-HCV (4.4%) than the controls. Patients with acute urethritis and cervicitis also showed a high prevalence of anti-HCV (3.6% and 6.7%, respectively). These data support the possibility of sexual transmission of hepatitis C virus.

Adolescent↗
PubMed1992

Frequent loss of heterozygosity for loci on chromosome 8p in hepatocellular carcinoma, colorectal cancer, and lung cancer.

Frequent loss of heterozygosity at chromosomal loci in a specific tumor type may indicate the presence of a tumor suppressor gene. We have examined loss of heterozygosity on chromosome 8p in paired tumor and constitutional DNA from 346 patients representing seven different types of human cancer. Frequent allelic losses were observed in hepatocellular carcinoma (22 of 46 cases, 47.8%), in colorectal cancer (12 of 26, 46.2%), and in non-small cell lung cancer (14 of 35, 40.0%), in contrast to low frequencies detected in breast cancer (5 of 56, 8.9%) and renal cell carcinoma (2 of 27, 7.4%). Ovarian cancer and gastric cancer showed intermediate frequencies of 33.3% and 22.2%. Subsequent analysis of 120 hepatocellular carcinomas and 94 colorectal cancers with five polymorphic markers along the short arm of chromosome 8 defined commonly deleted regions within the same chromosomal interval, 8p23. 1-8p21.3, suggesting that one or more tumor suppressor genes for both cancers may be present in that region.

Alleles↗
PubMed1992

Genetic changes of both p53 alleles associated with the conversion from colorectal adenoma to early carcinoma in familial adenomatous polyposis and non-familial adenomatous polyposis patients.

Mutation and loss of heterozygosity (LOH) in the p53 gene were analyzed in 274 colorectal tumors of 4 histopathological grades. Among 160 tumors from 40 familial adenomatous polyposis patients, none of 58 adenomas with moderate dysplasia had p53 mutations, whereas 8% (3 of 37) of severe adenomas, 15% (6 of 40) of intramucosal carcinomas, and 40% (10 of 25) of invasive carcinomas had p53 mutations. Only 3% (1 of 33) of severe adenomas showed both mutation and LOH, while 25% (6 of 24) of intramucosal carcinomas and 40% (10 of 25) of invasive carcinomas had both mutation and LOH. All intramucosal and invasive carcinomas that had mutations lost the other allele of the p53 gene. In 114 tumors from 86 non-familial adenomatous polyposis patients, similar results were obtained; no adenoma showed both mutation and LOH, but both alterations occurred in intramucosal and invasive carcinoma. As regards specificity in 56 mutations detected in the present study, the frequently affected codons were codons 175, 238, 245, 248, 273, and 282, 4 of these amino acids being arginine, and 72% (39 of 54) of all mutations were GC to AT transition. Although expression into p53 polyadenylated RNA was high in every invasive carcinoma irrespective of the presence of mutation or LOH, there was a correlation between mutation and protein level; immunostaining of p53 protein was negative in almost all adenomas, but it was positive in 86% of invasive carcinomas exhibiting p53 mutation. These data suggest that genetic changes on both alleles of the p53 gene through mutation and LOH, which result in abnormal protein accumulation, are involved in the conversion of adenoma to early carcinoma. Also, carcinoma cells with p53 mutations existing within adenoma tissues are detectable by immunostaining, even in formalin-fixed, paraffin-embedded specimens.

Adenoma↗
PubMed1992

Effects of the tripeptide substance P antagonist, FR113680, on airway constriction and airway edema induced by neurokinins in guinea-pigs.

FR113680 is a newly developed tripeptide substance P (SP) receptor antagonist. The effects of FR113680 on airway constriction and airway edema induced by neurokinins were investigated in guinea-pigs. In in vitro experiments, FR113680 inhibited the contraction of isolated guinea-pig trachea induced by SP and neurokinin A (NKA) in a dose-dependent manner with IC50 values of 2.3 x 10(-6) and 1.5 x 10(-5) M, respectively. The tracheal contraction induced by histamine and acetylcholine was not affected by FR113680. FR113680 (5 x 10(-5) M) also significantly inhibited the atropine-resistant contraction of isolated guinea-pig bronchi induced by electrical field stimulation. In in vivo experiments, FR113680 given i.v. inhibited SP-induced airway constriction in guinea-pigs at doses of 1 and 10 mg kg-1. However, FR113680 only inhibited NKA- and capsaicin-induced airway constriction by 40-50% even at a dose of 10 mg kg-1. FR113680 also inhibited SP-induced airway edema in guinea-pigs with the same potency as it inhibited SP-induced airway constriction. Histamine-induced airway constriction and airway edema were not affected at a dose of 10 mg kg-1. These results suggest that FR113680 preferentially inhibits responses induced by NK1 receptor activation (SP-induced airway constriction and airway edema), but is less effective on a NK2 receptor-induced response (airway constriction by NKA and neurogenic stimulation).

Amino Acid Sequence↗
PubMed1992

Mouse rRNA gene transcription factor mUBF requires both HMG-box1 and an acidic tail for nucleolar accumulation: molecular analysis of the nucleolar targeting mechanism.

RNA polymerase I requires at least two nucleolar transcription factors, UBF and SL-1, for ribosomal RNA gene (rDNA) transcription. UBF requires SL-1 for the formation of a stable initiation complex on the rDNA promoter region. We have determined the region of mouse UBF (mUBF) required for nucleolar targeting. Although mUBF has a nuclear localization sequence, this sequence alone is not sufficient for mUBF to accumulate in the nucleolus. Deletion analyses show that mUBF requires a wide region except for the N-terminal 101 amino acids for nucleolar targeting. Deletion of either the HMG-box1, a region crucial for rDNA binding, or the acidic tail, a region that may interact with SL-1, results in the loss of nucleolar targeting. We show by DNA affinity analysis that the HMG-box1 is absolutely necessary for mUBF to bind to the upstream control element of the rDNA. We also show that mUBFs with various internal deletions retain both nucleolar targeting and DNA binding ability. A clear correlation was demonstrated between the DNA binding and nucleolar targeting ability. These results suggest that UBF is transferred to the nucleus by its NLS and is sequestered in the nucleolus by its specific and stable binding to the rDNA promoter via HMG-boxes and the acidic tail.

Animals↗
PubMed1992

Autoantibodies to 64,000-M(r) islet cell protein in long-term type 1 (insulin-dependent) diabetic patients.

Autoantibodies to the 64,000-M(r) (64K) islet cell protein, identified as glutamic acid decarboxylase, were assayed in 46 Type 1 (insulin-dependent) diabetic patients with a disease duration of more than 5 years. Of 46 Type 1 diabetic patients, 18 (39.1%) were found to be positive for 64K antibodies and 12 of these patients had been diagnosed with autoimmune thyroid disease. Serum C-peptide levels were not detectable in 15 of 18 patients positive for 64K antibodies. The samples were also tested for titres of islet cell antibodies. Islet cell antibodies were detected in 15 (32.6%) of the 46 patients and all the islet cell antibody positive patients were also found to be positive for 64K antibodies. Furthermore, of these 15 patients 12 had previously been diagnosed with autoimmune thyroid disease. A correlation between levels of 64K antibodies and islet cell antibody titre revealed that higher levels of 64K antibodies were observed in patients who had higher islet cell antibody titre. These results demonstrate that most long-term Type 1 diabetic patients with 64K antibodies were also positive for islet cell antibodies complicated by autoimmune thyroid disease.

Adult↗
PubMed1992

Helicobacter pylori infection induces a decrease in immunoreactive-somatostatin concentrations of human stomach.

Immunoreactive-somatostatin (ir-somatostatin) concentrations of the gastric mucosa and gastric juice with Helicobacter pylori infection were measured in the human stomach. One hundred seventy-one patients (106 males, 65 females; mean age, 52.0; range, 19-84 years) were registered. Gastric juice and mucosa were obtained with the usual endoscopy procedure. Somatostatin concentration was measured by radioimmunoassay. The ir-somatostatin concentrations in the H. pylori-negative group were significantly higher than in the positive group gastric mucosa, whereas its levels in gastric juice tended to decrease with H. pylori infection. There was an inverse correlation between luminal ammonia levels and ir-somatostatin concentrations of the gastric mucosa. On the other hand, ir-somatostatin concentrations of the gastric mucosa significantly decreased with chronic and active inflammatory change. This decrease was not correlated with the grade of active inflammation, which was in close relation to H. pylori infection, but with the grade of chronic inflammation. These results indicate that H. pylori may reduce ir-somatostatin concentrations of the human stomach and that its effect is partly mediated via luminal ammonia produced by H. pylori.

Adult↗
PubMed1992

Regional cerebral blood flow in patients with schizophrenia. A preliminary report.

Regional cerebral blood flow was evaluated using Tc99m-HMPAO SPECT in 10 medicated patients with schizophrenia and 9 healthy volunteers. There were no prefrontal regions in the patient group with lower regional indices than in the control group. However, in the left hippocampal region, relative blood flow was significantly increased in the patient group compared with the control group. Furthermore, there was a relative increase in blood flow in the left basal ganglia of the patient group. A negative correlation coefficient was calculated between the relative blood flow in the left middle prefrontal cortex and the severity of the blunted affect, as well as between the relative blood flow in the left basal ganglia and the severity of the anhedonia-asociality. These findings indicate that prefrontal hypoactivity is not invariably present in all schizophrenics and that left basal ganglial hyperactivity may be associated with the effects of antipsychotic treatment and clinical improvement. Moreover, the left hippocampal hyperactivity may correspond to left limbic dysfunction in schizophrenia.

Adult↗
PubMed1992

Hepatitis C virus detection is facilitated by the combined use of c100 protein and GOR epitope.

Assay for the antibody to the c100 protein (anti-c100) lacks sensitivity in terms of detection of hepatitis C virus (HCV) in all samples. The author used anti-c100 and antibody to the GOR epitope (anti-GOR) by the enzyme-linked immunosorbent assay to examine 524 patients with chronic liver disease and 682 volunteer blood donors in Fukuoka, Japan. The prevalence of HCV infection, as revealed by the presence of anti-c100 and/or anti-GOR, was 3.9% in 540 volunteer blood donors, 12.7% in 142 volunteers with abnormal liver function, 7.4% in 135 patients with HBsAg-positive liver disease and 89.5% in 389 patients with non-A, non-B (NANB) liver disease. These results show a higher prevalence than demonstrated only by the anti-c100 in NANB liver disease patients (82.5%, P < 0.01). The concurrence of anti-c100 and anti-GOR in subjects with HCV infection was 23.8% in 21 volunteer blood donors, 44.4% in 18 volunteers with abnormal liver function and 61.2% in 348 NANB liver disease patients. The concurrence seems to increase with deterioration of liver function. We concluded that combination assay for anti-c100 and anti-GOR demonstrated a more accurate prevalence of HCV infection than single assay for anti-c100 among NANB liver disease patients, and that the presence of anti-GOR plays a role in liver disease in anti-HCV-positive subjects.

Adolescent↗
PubMed1992

Effect of luminal administration of thyrotropin-releasing hormone or somatostatin on gastric pH and interaction of these peptides in rats.

The effect of intraluminal administration of thyrotropin-releasing hormone (TRH) on gastric pH and release of luminal somatostatin, and a possible interrelationship between TRH and somatostatin in the rat stomach were studied. TRH was administered into the stomach via an intragastric tube at various doses (50 pg/kg-10 micrograms/kg) and gastric pH was measured after 15 min. The intraluminal administration of TRH significantly decreased gastric pH at doses over 1.0 ng/kg. Time-course studies at a dose of 100 ng/kg TRH exhibited a significant decrease in gastric pH at 15, 30 and 60 min. Furthermore, TRH administration caused a significant increase in immunoreactive-somatostatin (ir-somatostatin) concentrations in the gastric wall and a significant decrease in ir-somatostatin concentrations in the gastric juice. On the other hand, intraluminal administration of somatostatin caused a significant increase in ir-TRH concentrations in the gastric wall and a significant decrease in ir-TRH concentrations in the gastric juice, and significantly raised gastric pH at 5 min. These findings suggest that luminal TRH may exert a regulatory effect on gastric acid secretion, and that TRH may have a possible interaction with somatostatin in the modulation of gastric acid secretion.

Animals↗
PubMed1992

Time trends of HBsAg prevalence among blood donors in Fukuoka, Japan.

We examined time trends of the prevalence of hepatitis B surface antigen (HBsAg) among blood donors at the Fukuoka Red Cross Blood Center, Japan, during 1977-88. As was expected, a marked but artificial decrease in the HBsAg prevalence attributable to a notification program was detected. The seropositivities among males were uniformly higher than those among females. About 1% absolute rate decrease (approximately 50% relative rate reduction) was found among young donors aged 16-19 in seven years before the notification schedule. An age effect closely related to self-selection due to chronic hepatitis B virus (HBV) infection was demonstrated in the declining trends according to the advance of age. A remarkable birth cohort effect was also observed for both sexes. These data undoubtedly indicate that there were medical/iatrogenic factors as well as natural (sanitary/socioeconomic/nutritional) factors causing the reduction of chronic HBV infection.

Adolescent↗
PubMed1992

Effect of phosphoenolpyruvate on metabolic and morphological recovery of red cells after prolonged liquid storage and subsequent freezing in glycerol medium.

The present study was designed to determine the effects of (i) phosphoenolpyruvate (PEP) treatment of red blood cells (RBCs) previously cold stored for a prolonged period in a liquid medium and (ii) the freezing of these treated cells in glycerol. RBCs stored for 21 days at 4 degrees C were incubated for 30 min at 37 degrees C with rejuvenant solution containing 50 mM PEP, 60 mM mannitol, 30 mM sodium chloride, 25 mM glucose, and 1 mM adenine, pH 6.0, and then frozen at -80 degrees C for 4 weeks. Red cell recovery as frozen and thawed red cells (FTRCs) after deglycerolization was increased to 80 +/- 4% compared to 43 +/- 9% in units without rejuvenation; the percentage of PEP-treated FTRCs was similar to the percentage of FTRCs recovered from fresh RBCs within 5 days after donation. Incubation of RBCs with PEP solution restored ATP and 2,3-DPG to levels seen in fresh RBCs, and also facilitated transformation of crenated RBCs to discocytes. These results indicate that maximum recovery of viable RBCs can be attained when FTRCs are processed from cells stored in the frozen state after they had been rejuvenated with PEP even after prolonged liquid storage.

2,3-Diphosphoglycerate↗
PubMed1992

Regional differences in insulin receptor function in Werner's syndrome.

Werner's syndrome is a genetic disease characterized by premature aging and is often associated with glucose intolerance due to insulin resistance. The clinical manifestations in this syndrome are preferentially expressed in the face and acral regions without apparent involvement of the trunk. We compared insulin receptor binding and amino acid uptake of fibroblasts derived from the forearm that had sclerodermoid features, and from the abdomen that was apparently normal in a patient with Werner's syndrome. In normal controls, specific insulin binding was not different in forearm and abdomen-derived fibroblasts (10.72 +/- 2.11%, 10.40 +/- 1.27%, respectively). In the patient, however, specific insulin binding was reduced in the fibroblasts derived from the forearm compared with those derived from the abdomen (3.55%, 8.16%, respectively). Scatchard analysis revealed that the reduction in insulin binding of the forearm fibroblasts from the patient was due to a reduction in receptor number with no change in receptor affinity. The dose-response curve for insulin of alpha-aminoisobutyric acid (AIB) uptake is shifted to the right in the fibroblasts derived from the acral area. The results show that in a patient with Werner's syndrome, regional differences occur in fibroblast insulin receptor binding and function. This suggests early phenotypic expression of the genetic abnormality of insulin receptor function in these patients.

Abdomen↗
PubMed1992

The changes in body temperature, oxygen consumption, CO2 production and muscle protein turnover rate by selection for body size in Japanese quail, Coturnix coturnix japonica.

1. Body temperature, oxygen consumption, CO2 production and muscle protein degradation rate were measured in the three quail lines selected for body size, a random bred line (RR) and two lines selected for large (LL) or small (SS) body size. 2. The body temperature at 15 weeks of age was highest for small body size line and lowest for large body size line. 3. The body temperature, oxygen consumption and CO2 production of females were significantly higher than that of males. 4. The fractional degradation rate of muscle protein of SS, RR and LL lines were measured as 2.4, 1.6 and 1.2% per day in male, and 2.6, 1.7 and 1.4% per day in female.

Animals↗