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Biomedical subjects

K Okochi

Publications and source records attributed to K Okochi.

At least 37 records · Page 2Linked to original sources
PubMed1991

Identification of the region including the epitope for a monoclonal antibody which can neutralize human parvovirus B19.

In this study, we identified a region in the human parvovirus structural protein which involves the neutralization of the virus by a monoclonal antibody and site-specific synthetic peptides. A newly established monoclonal antibody reacted with both viral capsid proteins VP1 and VP2. The epitope was found in six strains of independently isolated human parvovirus B19. The monoclonal antibody could protect colony-forming unit erythroid in human bone marrow cell culture from injury by the virus. The monoclonal antibody reacted with only 1 of 12 peptides that were synthesized according to a predicted amino acid sequence based on nucleotide sequences of the coding region for the structural protein of B19 virus. The sequence recognized by the antibody was a site corresponding to amino acids 328 to 344 from the amino-terminal portion of VP2. This evidence suggests that the epitope of the viral capsid protein is located on the surface of the virus and may be recognized by virus-neutralizing antibodies.

Amino Acid Sequence↗
PubMed1990

Study of seroconversion of antibody to human T-cell lymphotropic virus type-I in children of Okinawa, Japan.

From 1983 to 1986, 1,813 children in nursery schools in Ishigaki Island and 1,228 children under 15 years old in the rural area in the Yaeyama District of Okinawa, Japan, were tested for anti-HTLV-I; 18 children (1.0%) in Ishigaki Island and 39 children (3.2%) in the rural area were positive. In order to survey when anti-HTLV-I developed in these children, their older serum samples were investigated retrospectively for 1 to 5 years. Two cases of seroconversion from anti-HTLV-I negative to positive were found between the age of 2 and 4, and there were no cases of seroconversion over 4 years old. Among the children who suffered maternal transmission of HTLV-I and developed anti-HTLV-I before the age of 15, about 80% of the children were considered to have anti-HTLV-I before the age of 2, and the remainder developed anti-HTLV-I before the age of 4.

Adolescent↗
PubMed1990

Serological studies of an SLE-associated antigen-antibody system discovered as a precipitation reaction in agarose gel: the HAKATA antigen-antibody system.

Current population studies indicate that the HAKATA antigen is one of the normal plasma proteins not yet completely characterized. The frequency of Japanese donor, patients and Swedish patients was 100%, 99.99% and 99.98%, respectively. Anti-HAKATA antibody production was found in three patients, all with systemic lupus erythematosus (SLE). Transient HAKATA antigen deficiency was found in 13 patients and appeared to be strongly associated with SLE (11 out of 13). None of the 14 SLE patients had a history of transfusion. It is therefore concluded that anti-HAKATA antibody is produced as one of the autoantibodies in SLE.

Antibody Formation↗
PubMed1989

Prevention of transmission of human T-lymphotropic virus type 1 (HTLV-1) through transfusion, by donor screening with antibody to the virus. One-year experience.

To prevent the transmission of human T-lymphotropic virus, type 1 (HTLV-1) during blood transfusion, a program was implemented to screen donors for antibodies to the virus, using a newly developed, passive agglutination (PA) method. During the period April 1986 to March 1987, 675 recipients of donor blood in whom the antibody to HTLV-1 was not present before transfusion were followed for at least 50 days after transfusion. One of these 675 seroconverted despite the transfusion of screened blood, but this seroconversion rate (0.15%) represents a marked decrease from the rate of 8.3 percent prevalent before donor screening began. The rate in the Fukuoka area of donors seropositive for anti-HTLV-1 is 5.34 percent, as detected by the PA method and 1.80 percent, as assessed by the indirect immunofluorescence (IF) technique, with PA-positive but IF-negative blood units thus accounting for 3.5 percent (5.34-1.80) of the total blood donated. The seroconversion rate among recipients transfused with blood screened by IF (at Kyushu University Hospital only) from 1981 to 1985 was 0.41 percent, which was not significantly different from the rate of 0.15 percent observed after PA screening. The discrepancy between PA and IF in the rate of seropositivity was due, in part, to the higher sensitivity of PA in detecting anti-HTLV-1. It is proposed that all donor blood in areas where HTLV-1 is endemic be screened by PA before transfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Agglutination Tests↗
PubMed1989

[Reference value of glutamic transaminase to prevent non-A non-B post-transfusion hepatitis].

GPT is currently used as a surrogate test for detection of the non-A, non-B carrier state. Among the patients who received the blood at least one blood unit from donor with relatively high level of GPT (26-35 KU), incidence of post-transfusion NANB hepatitis was higher than that of the patients who received only blood with low level of GPT (less than or equal to 25 KU). It is expected that introduction of lower GPT cut-off value will substantially reduce the incidence of post-transfusion NANB hepatitis. We reviewed several factors, such as gender, age and body weight that could potentially affect GPT activity, using the data of 40,967 regular blood donors for GPT who donated at Fukuoka Red Cross Blood Center from October to November, 1987. The upper limit of normal GPT for males is significantly higher than that of females. GPT values in both males and females progressively increase with the age and body weight. It would therefore seem that gender, age and body weight should be taken into account in resetting of GPT cut-off values to prevent post-transfusion NANB hepatitis.

Adolescent↗
PubMed1988

Elevated serum antibody titers to Epstein-Barr virus in HTLV-I-associated myelopathy (HAM).

We studied the serum antibody titers to Epstein-Barr virus (EBV) in 11 patients with HTLV-I-associated myelopathy (HAM). HAM patients showed significant increases in IgG antibodies to EBV-capsid antigen (VCA) and -early antigen (EA) and in VCA-specific IgA compared with 25 seronegative subjects. However, there were no significant differences in antibodies to EBV-nuclear antigen (EBNA) or to other viruses between the two groups. In HAM patients, altered antibody responses occurred specifically to EBV-associated antigens, not to other viruses.

Adult↗
PubMed1988

Altered subsets of peripheral blood lymphocytes in patients with HTLV-I associated myelopathy (HAM).

We studied subsets of peripheral blood lymphocytes (PBL) from 12 patients with human T-lymphotropic virus type I (HTLV-I) associated myelopathy (HAM). The percent of OKT8+ cells was significantly decreased, and the percentages of OKDR+ cells and IL-2R+ cells and the ratio of OKT4+ cells to OKT8+ cells were significantly increased compared with either HTLV-I seronegative healthy adults (controls) or HTLV-I seropositive non-HAM subjects (carriers). The subsets of PBL from eight carriers showed no differences from those in controls. The patients with HAM showed significantly higher antibody titers to HTLV-I compared with carriers. These altered PBL subsets and high HTLV-I antibody titers in the patients suggest that immune functions are in an activated state in HAM.

Adult↗
PubMed1988

Spontaneous proliferation of peripheral blood lymphocytes increased in patients with HTLV-I-associated myelopathy.

We found unstimulated (spontaneous) peripheral blood lymphocyte (PBL) proliferation significantly increased in 14 patients with human T-lymphotropic virus (HTLV)-I-associated myelopathy (HAM) compared with findings in HTLV-I seropositive non-HAM carriers (N = 8) or HTLV-I seronegative controls (N = 16). The proliferative response to phytohemagglutinin, concanavalin A, or pokeweed mitogen was decreased in the HAM patients. Cell clusters were frequent in cultures of unstimulated PBL from the HAM patients, but much less common in the controls or carriers. This spontaneous PBL proliferation was depressed when adherent-cell populations were depleted from the cultures. IL-2 activity increased in the supernatant of 3-day cultured cells from HAM patients, but not in cultured cells from the controls. Since IL-2 receptor positive cells increased in HAM, this spontaneous PBL proliferation is probably a response to IL-2 through the expression of IL-2 receptors.

Adult↗
PubMed1987

Absence of HTLV I from New Zealand.

Sera from 1,943 individuals from Auckland, New Zealand, were tested for the presence of serum antibodies to human T cell lymphotropic virus I (HTLV I), mainly with an enzyme-linked immunosorbent assay (ELISA) with cell extracts as target antigen. The individuals tested were blood donors and mostly Caucasian, but included indigenous Maoris and representatives of several groups of Pacific islanders now resident in New Zealand. Also included were 37 patients with various hematological malignancies, including seven with T cell leukemias. Although 1% of samples were positive by ELISA, none of these were confirmed as positives by Western blotting. On the basis of these results we consider that it is unlikely that HTLV I infection occurs in Auckland; however, we cannot exclude the possibility that pockets of virus infection may occur in other parts of New Zealand or the South Pacific.

Adolescent↗
PubMed1987

Incidence of antibody to HTLV-I is not increased in Japanese MS patients.

To examine the association between MS and anti-human T-cell lymphotropic virus-I (HTLV-I) antibody, we studied serum and CSF antibody to HTLV-I in 27 Japanese MS patients by an indirect immunofluorescence method sensitive and specific enough to detect carriers of HTLV-I. The antibody was detected in 3 of 27 MS patients (11.1%), in 4 of 48 patients (8.3%) with other neurologic diseases, and in 8.3% of 2,500 healthy blood donors. There was no significant difference in the incidence between the three groups. The titer of the antibody was low in CSF when compared with that in serum in all seropositive MS patients. Fluctuations in the CSF antibody titer were not observed in any of 14 MS patients sampled repeatedly.

Adult↗
PubMed1986

Transmission of human T-cell leukemia virus (HTLV-I) by blood transfusion: demonstration of proviral DNA in recipients' blood lymphocytes.

Human T-cell clones bearing antigens encoded by human T-cell leukemia/lymphoma virus (HTLV-I) were isolated from 6 patients who produced antibodies against HTLV-I after having received anti-HTLV-I-positive blood units containing cell components. On the other hand, it was not possible to isolate clonal cells carrying viral antigens from the recipients who did not produce antibodies. The clonal cell lines had the same surface markers as neoplastic cells of adult T-cell leukemia and had the HLA phenotype of the recipients themselves. Proviral DNA of HTLV-I was demonstrated in each of the clonal cell lines. The site of integration was different in each case even if the clones were derived from the same recipient. These results indicate that blood transfusion can cause persistent HTLV-I infection.

Adolescent↗
PubMed1986

Intrafamilial transmission of adult T cell leukemia virus.

In an investigation of the mode of transmission of adult T cell leukemia virus (ATLV) in family settings, 275 male and 444 female subjects positive for antibody to ATLV-associated antigen (anti-ATLA) were studied. Their children were surveyed for anti-ATLA status. None of the 82 children of a positive father and a negative mother were positive for anti-ATLA. In contrast, the antibody prevalence among children with a positive mother and a positive or negative father was 27.9% and 19.9%, respectively. Of 39 parents who had one or more anti-ATLA-positive children less than 20 years old, 56.3% of the fathers and 97.1% of the mothers were anti-ATLA positive. Algorithm computation showed the possibility of ATLV transmission from husband to wife to be 60.8% and from wife to husband to be 0.4% over a 10-year period. These data suggest that ATLV is transmitted from mother to child and from husband to wife in family settings.

Adolescent↗
PubMed1986

Intrafamilial clustering of anti-ATLA-positive persons.

A total of 1,333 persons in 627 families were surveyed for presence of antibody to adult T-cell leukemia-associated antigen (anti-ATLA). Each person was classified according to the anti-ATLA status (positive for sample 1, negative for sample 2) of the head of household of his or her family. In sample 1, the sex- and age-standardized prevalence of anti-ATLA was 38.5%. This was five times as high as the standardized prevalence in sample 2 (7.8%). There were significant differences in prevalence of anti-ATLA between males in samples 1 and 2 and between females in samples 1 and 2. In every age group, prevalence in sample 1 was greater than that in sample 2 except for males aged 60-69 years. In each of four subareas, families in sample 1 had higher standardized prevalence (29.6-42.5%) than families in sample 2 (6.0-9.7%). Although crude prevalence decreased with family size in sample 1 (62.1-25.4%) as well as in sample 2, indirectly standardized prevalence was almost equal within each sample, regardless of number of family members. The degree of aggregation was independent of locality and family size. These data suggest that anti-ATLA-positive persons aggregate in family units.

Antibodies, Viral↗