Biomedical subjects

H Ichimura

Publications and source records attributed to H Ichimura.

At least 37 records · Page 2Linked to original sources

PubMed1997

Suppression of HIV replication in vitro by CD8+ T-cells from HIV-infected and HIV-seronegative individuals.

The inhibitory effect of CD8+ T-cells from HIV-infected or HIV-seronegative individuals on HIV replication in the naturally-infected CD4+ T-cells in vitro was examined. Not only autologous CD8+ T-cells from HIV-infected individuals but also allogeneic CD8+ T-cells from HIV-seronegative individuals prevented or delayed HIV replication, even in transwell cocultures using a semi-permeable 0.45 micron filter. The level of the inhibitory effect of allogeneic CD8+ T-cells from the HIV-seronegative individuals on the HIV replication was varied among CD4+ T-cells obtained from HIV-infected individuals used. The results suggested that CD8+ T-cells from HIV-seronegative individuals as well as HIV-infected individuals could produce some cytokine(s) which suppress HIV replication in vitro. The sensitivity to the cytokine(s) might be variable among HIV strains, depending on differences in the nucleotide sequence of different HIV-1 strains. Further studies of control of HIV replication by CD8+ anti-HIV cytokine(s) should provide new strategies for the therapy of HIV infection.

CD8-Positive T-Lymphocytes↗

PubMed1996

Sources of selection bias in evaluating social programs: an interpretation of conventional measures and evidence on the effectiveness of matching as a program evaluation method.

This paper decomposes the conventional measure of selection bias in observational studies into three components. The first two components are due to differences in the distributions of characteristics between participant and nonparticipant (comparison) group members: the first arises from differences in the supports, and the second from differences in densities over the region of common support. The third component arises from selection bias precisely defined. Using data from a recent social experiment, we find that the component due to selection bias, precisely defined, is smaller than the first two components. However, selection bias still represents a substantial fraction of the experimental impact estimate. The empirical performance of matching methods of program evaluation is also examined. We find that matching based on the propensity score eliminates some but not all of the measured selection bias, with the remaining bias still a substantial fraction of the estimated impact. We find that the support of the distribution of propensity scores for the comparison group is typically only a small portion of the support for the participant group. For values outside the common support, it is impossible to reliably estimate the effect of program participation using matching methods. If the impact of participation depends on the propensity score, as we find in our data, the failure of the common support condition severely limits matching compared with random assignment as an evaluation estimator.

Bias↗

PubMed1996

[Recurrence of AL type primary localized pulmonary amyloidosis].

A 52-year-old female, who was diagnosed primary pulmonary amyloidosis by left open lung biopsy 11 years ago, has been pointed out chest abnormal shadow in the opposite lung for 9 years. Two masses situated in the right S3a and S4 have been growing gradually with suspicion of malignancy. The right open lung biopsy revealed amyloidosis by frozen section and wedge resections were performed. Microscopic findings were compatible with AL type amyloid protein. We reported a rare case of recurrence of localized primary pulmonary amyloidosis.

Amyloidosis↗

PubMed1995

The amino acid sequence and interaction with the nucleosome core DNA of transition protein 4 from boar late spermatid nuclei.

The primary structure of transition protein 4 (TP4) from boar late spermatid nuclei was determined by automated Edman degradation of S-pyridylethylated protein and of peptides generated by cleavage with Staphylococcus aureus V8 protease, lysyl endopeptidase and CNBr. Boar TP4 is a basic protein consisting of a highly basic amino-terminal half (residues 1-73) and a less basic carboxy-terminal half (residues 74-138). The latter half includes a highly hydrophobic segment, a four-times tandemly repeated sequence, N(G)QNKR(K)X, and a carboxy-terminal segment containing Trp126. Ultraviolet absorption and CD spectra of TP4-rat-liver-nucleosome-core-DNA (double-stranded DNA) complexes suggest a TP4-induced local melting of DNA. Although at 1 mM NaCl TP4 brought about a slight stabilization of the DNA against thermal melting, a destabilization of the DNA was observed at 50 mM NaCl. From the results of quenching of tryptophan (Trp126) fluorescence of TP4 upon its binding to double-stranded and single-stranded boar liver nucleosome-core DNA at 50 mM NaCl, the apparent association constants for the binding of TP4 to double-stranded and single-stranded DNA were calculated to be 7.3 x 10(3) M-1 and 4.1 x 10(3) M-1, respectively. These results suggest that TP4, having different domain structures from TP1-3 and a higher affinity for double-stranded DNA, induces a local destabilization of DNA probably through the stacking of Trp126 with nucleic acid bases.

Amino Acid Sequence↗

PubMed1995

Polymerase substrate depletion: a novel strategy for inhibiting the replication of the human immunodeficiency virus.

Mycophenolic acid (MPA), an inhibitor of inosine monophosphate dehydrogenase, shows strong anti-HIV activity in vitro in both human peripheral blood CD4+ lymphocytes and macrophages, as well as established human cell lines. MPA shows its greatest antiviral effects during the early stages of HIV infection. By limiting the rate of de novo synthesis of guanosine nucleotides, this drug apparently blocks the activity of reverse transcriptase, which is required for the formation of the HIV DNA provirus. MPA provides a novel strategy for inhibiting the replication of HIV and should be considered in clinical trials of antiviral therapies.

Antiviral Agents↗

PubMed1994

Effect of dibutyryl cyclic AMP on morphologic features and marker production of human cervical argyrophil small-cell carcinoma cell line.

The effect of dibutyryl cyclic AMP (dB-cAMP) on the morphologic features and marker production of a human cervical argyrophil small-cell carcinoma (ASCC) cell line was examined. Following 1-5 days' exposure to 5 mM dB-cAMP, morphologic differentiation as defined by the expression of cytoplasmic processes (stellate cells) was observed. The number of stellate cells depended on the dose of dB-cAMP and incubation time. Shortly after removal of dB-cAMP from the culture medium, the treated cells returned to their original spherical shape. dB-cAMP caused a reduction in the growth rate of cells which recovered after removal of the agent. The morphological changes appeared not to be the result of growth inhibition by dB-cAMP, because the cells maintained in a serum-free medium did not show any change in shape. Electron microscopic study revealed the development of intracytoplasmic microtubules, microfilaments, and an increase in the number of neurosecretory granules in the treated cells. The levels of neuron-specific enolase, serotonin and gastrin in treated cells were significantly higher than those in untreated controls. These findings indicate that a reversible differentiation of cultured ASCC cells into neuroendocrine cells occurs in a growth medium containing dB-cAMP.

Biomarkers, Tumor↗

PubMed1994

Hepatitis C virus genotypes, reactivity to recombinant immunoblot assay 2 antigens and liver disease.

To clarify the relationship between hepatitis C virus (HCV) genotypes and liver disease, we typed HCV genomes in the sera of 151 blood donors, 180 patients with type C chronic liver disease (CLD), and 30 haemophiliacs residing in Hiroshima, Japan. All of the subjects were positive for anti-HCV and HCV-RNA, and were examined for seroreactivity to HCV-specific antigens. The HCV genotypes were determined by polymerase chain reaction (PCR) with type-specific primers deduced from the putative core region of the HCV genome. Significantly more (P < 0.001) type III HCV was found in the samples from the CLD patients (80%) than in those from the blood donors (55%). Significantly more (P < 0.001) type III HCV was found in the samples from the blood donors (29.1%) than in those from the CLD patients (11.7%). There was no significant difference in the distribution of the HCV types among the patients with chronic active hepatitis, liver cirrhosis, and hepatocellular carcinoma. A four-antigen recombinant immunoblot assay (RIBA-2) assay was used to compare the serum samples for their reactivity to a range of structural and nonstructural peptides specific for HCV (5-1-1, C100-3, C33c, and C22-3). The frequency of seropositivity to 5-1-1 and C100-3 was significantly higher (P < 0.001) in type II HCV-infected blood donors than in type III HCV-infected donors (68.2% and 65.9% vs. 4.5% and 22.7%, respectively). Among the type III HCV-infected individuals, the CLD patients had a significantly higher (P < 0.01) frequency of seropositivity to 5-1-1 than the blood donors (33.3% vs. 4.5%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Biological, serological, and genetic characterization of HIV-1 subtype E isolates from northern Thailand.

Twenty-three HIV-1 isolates were recovered from PBMCs from 26 HIV-1-seropositive individuals in northern Thailand. The viruses grew readily in human PBMCs but only 7 of 17 (41.2%) and 5 of 17 (29.4%) replicated and only at a low level in primary macrophages and in established T cell lines, respectively. By immunoblot assays, sera from Thai subjects were strongly reactive with gp120 from a Thailand isolate, moderately reactive with a Rwandan isolate, and weakly reactive with a North American strain. These three viruses represent, respectively, examples of subtypes E, A, and B as classified by the sequences of the envelope region. Serological assays indicated that broadly reactive rather than type-specific neutralizing activity was detected among these northern Thai sera. The majority of the sera (approximately 75%) neutralized a representative Thailand isolate and the Rwanda isolate but only 55% neutralized the North American strain. However, the difference was not statistically significant. The genetic analyses indicated that nearly all the Thai isolates were highly homogeneous and distinct from the North American/European consensus sequence (subtype B); they belong to subtype E. This is the first report providing biological, serological, and genetic characterization of HIV-1 strains from Thailand. The findings suggest these viruses were recently introduced into the country and that serological evaluation of viral strains needs to be considered along with genetic subtyping when developing an HIV-1 vaccine.

Adult↗

PubMed1994

Isolation of intact transition protein 4 from boar late spermatid nuclei.

Boar transition protein 4 was extracted with acid from the late spermatid nuclei, and separated from the transition protein-degrading proteases by ion-exchange chromatography on Fractogel EMD SO3- 650 (M). The transition protein was further purified by HPLCs on Nucleosil 300 7C18 and Diol-200. The circular dichroic spectra of the protein with and without dithiothreitol showed that the protein had beta-form predominantly. Although sodium dodecyl sulfate affected the tertially structure of the protein, the beta-form was well retained. These indicate that the protein has a structure-forming potential for the beta-structure.

Animals↗

PubMed1993

Huge subdural empyema with unusual presentation in infant--case report.

An 11-month-old boy presented with a huge subdural empyema in the left hemisphere associated with a subsequent contralateral chronic subdural hematoma. Burr-hole drainage and antibiotic therapy achieved a successful outcome. Subdural empyema may result from hematogenous seeding of infection into a pre-existing chronic subdural hematoma.

Brain↗

PubMed1992

Prevalence of four blood-borne viruses (HBV, HCV, HTLV-I, HIV-1) among haemodialysis patients in Japan.

To investigate the prevalence of four blood-borne viruses among a cohort of haemodialysis (HD) patients in Japan, hepatitis B surface antigen (HBsAg), antibody to hepatitis C virus (anti-HCV), antibody to human T-cell lymphotropic virus type-I (anti-HTLV-I), and antibody to human immunodeficiency virus type-1 (anti-HIV-1) were studied in the sera from 393 consecutive HD patients and in the sera from 786 age- and sex-matched healthy individuals from the general population (controls). The prevalence of anti-HCV and anti-HTLV-I was significantly higher in HD patients than in the controls (17.8% vs. 1.1% and 3.8% vs. 0.5%), but the prevalence of HBsAg showed no significant difference. No patients or controls were positive for anti-HIV-1. In HD patients with no history of blood transfusion, anti-HCV was detected in only one (2.1%) of 48 patients undergoing HD treatment for less than 3 years, and there was no significant difference between the prevalence of anti-HCV in these patients and in the controls. In HD patients who had received blood transfusion, anti-HTLV-I was detected in only one (1.0%) of 103 patients undergoing HD treatment for less than 3 years, and there was no significant difference between the prevalence of anti-HTLV-I in these patients and in the controls. These findings suggest that in recent years, the risk of HCV transmission by routes other than blood transfusion in HD patients is low, and that of HTLV-I transmission by transfusion is very low or non-existent.

Adolescent↗

PubMed1992

Hepatitis C virus RNA and hepatitis C virus antibody in the serum of patients with abnormal liver function.

In order to elucidate the relation between hepatitis C virus (HCV) RNA and antibody to HCV (anti-HCV) in serum, we examined samples of serum collected from 228 HBsAg-negative patients, with abnormal alanine aminotransferase (ALT) values, for HCV-RNA by nested polymerase chain reaction (PCR) assay and for anti-HCV using C100 protein as the antigen. HCV-RNA was detected in 99 (92.5%) of 107 anti-HCV-IgG-positive samples, regardless of ELISA optical density cut-off value (ELISA ratio), and in 34 (28.1%) of 121 anti-HCV-IgG-negative samples in which the frequency of the presence of HCV-RNA became higher in proportion to the ELISA ratio. Among 42 discordant cases (34 anti-HCV-IgG-negative, RNA-positive cases and eight anti-HCV-IgG-positive, RNA-negative cases), 10 were positive for anti-HCV-IgM (8/34 and 2/8, respectively) irrespective of clinical status. These findings suggest that in patients with abnormal ALT values, even if they are anti-HCV-IgG negative, HCV infection cannot be excluded. Furthermore, PCR assay for detecting HCV-RNA may be more suitable for identifying patients with infectious virus than is detection of anti-HCV-IgG. Detection of anti-HCV-IgM may also be useful.

Alanine Transaminase↗

PubMed1992

[Studies on hepatitis C virus infection in haemodialysis patients].

To examine the prevalence of hepatitis C virus (HCV) in haemodialysis patients without blood transfusion in Hiroshima Prefecture, antibody to HCV (anti-HCV) was studied by the Ortho ELISA Kit in sera from 393 consecutive haemodialysis patients and in sera from 510 age and sex matched healthy members of the general population (control). An additional confirmatory test was done by a recombinant immunoblot assay. 1) Anti-HCV was detected in 70 of the 393 dialysis patients and 3 of the 510 healthy controls (17.8% vs 0.6%, p less than 0.01). Prevalence of anti-HCV in haemodialysis patients sera was increased by the volume of blood transfusion, and even in dialysis patients who had no blood transfusion, the frequency of anti-HCV positivity (9.2%) was greater than the healthy controls (p less than 0.01). Thus, the major route of HCV transmission in haemodialysis patients without blood transfusion may be via the haemodialysis treatment. 2) The prevalence of anti-HCV increased significantly with the ALT level and abnormal ALT activity of the anti-HCV positive group were significantly greater than that of the negative group. Thus, it is suggested that HCV infection may be an etiologic factor of liver dysfunction in haemodialysis patients.

Adult↗

PubMed1991

Establishment and characterization of a new cell line TC-YIK originating from argyrophil small cell carcinoma of the uterine cervix integrating HPV16 DNA.

A new cell line, designated TC-YIK, was established from YIK-1 tumor cells, derived from argyrophil small cell carcinoma (ASCC) of the uterine cervix, and serially heterotransplanted into nude mice, integrating human papillomavirus type 16 (HPV16) DNA. The population doubling time of TC-YIK was approximately 21.6 hours at the 119th subculture. Subcutaneous injection of 1 x 10(8) TC-YIK cells into nude mice yielded a solid tumor. The cytologic appearance of TC-YIK was similar to that of YIK-1. The TC-YIK cells contained argyrophil granules and neurosecretory granules in the cytoplasm and showed positive immunohistochemical staining for neuron-specific enolase, serotonin, and chromogranin. Thus, TC-YIK retained the histochemical characteristics of ASCC. The TC-YIK cells contained HPV16 DNA in a multiple-copy integrated form and actively transcribed the integrated HPV16 genome. Amplification of the c-myc oncogene was observed in the TC-YIK cells. These data suggest that TC-YIK is a useful in vitro experimental model of ASCC and that HPV16 and c-myc may play some role in the genesis of this malignant tumor and/or maintenance of the transformed TC-YIK phenotype.

Animals↗

PubMed1991

Chromosomal insertion and amplification of human papillomavirus 16 DNA sequences in a cell line of argyrophil small cell carcinoma of the uterine cervix.

The chromosomal location of human papillomavirus (HPV) 16 DNA sequences integrated in a cell line derived from argyrophil small cell carcinoma of the uterine cervix was determined by means of fluorescence in situ hybridization (FISH). The HPV 16 DNA sequences were integrated near a fragile site and the location of the c-myc oncogene at 8q24.1. Amplification of the integrated viral sequences resulted in an abnormally banded region. The amplified HPV 16 DNA sequences were also detected in every interphase nucleus by FISH.

Carcinoma, Small Cell↗

PubMed1990

[Combination therapy with ofloxacin and chloramphenicol against typhoid fever].

Recently we experienced two male typhoid patients who required additional treatment with CP sodium succinate (CP succinate) to OFLX therapy. Although both of the cases were administered 900 mg/day of OFLX orally for three and four days, respectively, the clinical efficacies were not sufficient. We added 2.0 g/day of CP succinate intravenously for six days, although a lasting high fever returned to normal level in a few days. The administration of OFLX was continued up to 14 days. The daily doses of OFLX during the co-medication with CP succinate were 600 mg in one case and 900 mg in the other case. In both cases no recurrence was observed clinically and bacteriologically for six months after their discharge. No adverse reaction was observed throughout the therapy.

Adolescent↗

PubMed1989

[HBV carriers and HDV superinfection--studies on the cases of HBsAg clearance].

We studied the annual clearance rates of hepatitis B surface antigen (HBsAg) and the annual seroconversion rates of HBsAg (HBs seroconversion rates), and the correlation between HBsAg clearance and hepatitis delta virus (HDV) superinfection in hepatitis B virus (HBV) carriers in Japan. Out of 1,029 HBV carriers followed for more than 36 months, 56 cases were cleared of HBsAg from the sera, and 24 of these cases developed hepatitis B surface antibody. The annual clearance rate of HBsAg was 0.94% and the annual HBs seroconversion rate was 0.27%. These rates increased with aging, especially above 30 years of age. Antibody to HDV was detected in three cases with increased serum alanine aminotransferase activity preceding HBsAg clearance. These data indicate that HDV superinfection may play a role in induction of the HBsAg clearance in HBV carriers in Japan.

Adult↗

PubMed1989

[Studies on the clinical and bacteriological effects of ofloxacin on the typhoid patients and carriers].

Fundamental and clinical studies of OFLX were performed against the patients with typhoid fever and typhoid carriers. 1) Clinical and bacteriological effects: Eight patients with typhoid fever and 3 typhoid carriers were treated with OFLX. Daily doses of the agent were 900 mg in 5 adult patients, 600 mg in a child patient and 3 adult carriers. In one case of the remaining 2 adult patients, daily doses of the agent changed from 800 mg to 1200 mg and from 900 mg to 1200 mg in the other one. The duration of the treatment was 9, 14 or 21 days. Clinical efficacies of OFLX against the patients proved 4 cases were "excellent", 3 cases were "good" and one case was "poor". The eradication of Salmonella typhi recognized in all cases containing 3 carriers with the exception of the "poor" case. Adverse reactions were observed transiently in 3 patients, such a slight decrease of RBC count, decrease of granulocyte count and elevation of GPT value respectively. 2) Antimicrobial activity: MICs of OFLX against 40 strains of S. typhi were 0.05 micrograms/ml and 0.1 micrograms/ml. The MICs of NFLX, CPFX and T-3262 were almost the same as that of OFLX, and those of ENX, NY-198 and NA were higher than that of OFLX. The peaks of MIC of CP and ABPC, first choice drug against typhoid fever, were 1.56 micrograms/ml and 0.38 micrograms/ml respectively. 3) Serum concentration; Serum concentrations of OFLX were serially measured on 5 patients through the day. The concentrations of the drug were distributed from 0.82 micrograms/ml to 6.34 micrograms/ml at 6.30 a.m. and from 2.52 micrograms/ml to 11.2 micrograms/ml at 9:00 p.m. Those of the day time showed considerable individual differences.

Adult↗