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Biomedical subjects

J K Youn

Publications and source records attributed to J K Youn.

At least 19 recordsLinked to original sources
PubMed1992

Detection of antibodies to human nerve antigens in sera from leprosy patients by ELISA.

Anti-neural antibodies have been implicated to play a role in the pathogenesis of nerve damage in leprosy patients. To find the relationship between anti-neural antibodies and clinical findings, we attempted to detect antibodies against neurofilament-enriched proteins by ELISA in sera from leprosy patients. Of 289 sera from leprosy patients, 74 (25.6%) had significant anti-neural antibodies; in contrast, 1 (5.0%) of 20 tuberculosis patients and 11 (7.1%) of 154 controls were seroreactive to nerve antigen. When clinical types were considered, a significant level of anti-neural IgG antibodies was detectable in 53 (30.1%) of 176 sera from lepromatous patients compared with 21 (18.6%) of 113 sera from tuberculoid patients, indicating that lepromatous patients were more likely to be seropositive to nerve antigens in ELISA. Some of the ELISA-reactive sera showed antibody reactivity with 38-kD, 40-kD and 43-kD nerve antigens in Western blotting analysis. There was no apparent correlation between seroreactivity to nerve antigens and bacterial load in leprosy patients. Although there was no statistical significance, anti-neural antibodies were detectable more often among the patients on chemotherapy than the untreated and among the patients with erythema nodosum leprosum than without. The results, therefore, suggest that anti-neural antibodies are elicited during the course of leprosy and may be associated with the extensiveness of nerve involvement in the patients.

Animals↗
PubMed1992

Point mutation at codon 12 of the c-Ha-ras gene in human gastric cancers.

The molecular mechanisms of the carcinogenic process of gastric cancer have not been fully understood yet. In order to know whether c-Ha-ras gene is being involved in the process of gastric carcinogenesis, 8 gastric cancer cell lines, 8 cases of gastric cancer and same number of adjacent dysplasia were analyzed for the presence of mutation at codon 12, 13 and 61 of the c-Ha-ras gene by using polymerase chain reaction (PCR) and mutant-specific oligonucleotide hybridization. Point mutations at codon 12 of the c-Ha-ras gene were found in 2 out of 8 gastric cancer and dysplasia samples in one case, but we found no mutation at codon 13 or 61 of the c-Ha-ras gene. These results suggest that the frequency of mutation of the c-Ha-ras gene detected by sensitive PCR technique is low indeed, however it would be notable that such a genetic change has been detected in the dysplastic lesion of the gastric cancer patient.

Base Sequence↗
PubMed1992

Natural killer activity and antibody-dependent cellular cytotoxicity in patients with primary lung cancer.

The NK activity and ADCC of peripheral blood mononuclear cell were examined to evaluate the contribution of ADCC and NK activity to host immune response against lung cancer. The NK activity and ADCC were examined in 58 patients with primary lung cancer and 40 healthy volunteers as normal controls. The NK activity of patients with lung cancer was significantly subnormal, but ADCC was at a normal level. The NK activity was decreased in non-small cell lung cancer (NSCLC), but not in small cell lung cancer (SCLC) compared to normal controls. According to stage, the NK activity in stage II, III-M0 and III-M1 NSCLC showed low levels compared to that of stage I NSCLC, but there was no difference of NK activity in patients with SCLC. The NK activity was not affected by performance status. There was no significant difference of ADCC in patients with lung cancer according to cell type, stage and performance compared with that of normal controls. The NK activity and ADCC were not changed after chemotherapy and operation respectively.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1992

Should all the N3 lymph nodes group metastasis be regarded as distant metastasis (M1) in curatively resected gastric cancer?

Recently, metastasis to N3 lymph nodes group was regarded as distant metastasis by the new TNM staging system due to poor overall survival. However, the 5-year overall survival rate of patients with metastasis to N3 groups was 34.5% after curative surgery. Moreover, in patients with metastasis to lymph node subgroups of #12, #13, #14, the overall 5-year survival rate increased upto 47.2% after curative resection and adjuvant chemotherapy. This was similar to that of the patients with metastasis to N1 and N2 lymph nodes groups. But in these highly tumor burden states, no survival benefit was found with the addition of immunotherapy to chemotherapy as we achieved in stage II and III. Therefore, we suggest that, at least, metastasis to #12, #13, #14 lymph nodes subgroups should not be categorized as a distant metastasis. And in these situations, active curative radical surgery with extended lymphadenectomy and adjuvant chemotherapy are recommended.

Adult↗
PubMed1990

Adjuvant treatment of operable stomach cancer with polyadenylic.polyuridylic acid in addition to chemotherapeutic agents: a preliminary report.

A randomized trial of polyadenylic.polyuridylic acid [poly(A).poly(U)] in addition to chemotherapy was undertaken in patients with stomach cancer following curative gastrectomy. They were randomized into a group of 108 patients receiving chemotherapy plus poly(A).poly(U) and a control group of 116 patients receiving chemotherapy alone. Chemotherapy consisted of injections of 5-fluorouracil, 12 mg/kg once weekly and adriamycin, 40 mg/m2 once every 3 weeks, continuously after operation. Poly(A).poly(U) was infused in a 100 mg dose, once a week six times from 5 days after the first injection of chemotherapeutic agents and 6 months later in a half dose similarly. At 55 months after initiation of the trial, the mean follow-up periods were 24 months for both groups. It has been revealed that patients who received the combined treatment postoperatively showed a lesser mortality and lower rate of recurrence, both reflecting significant increases in overall (P less than 0.05) and relapse-free (P less than 0.02) survivals as compared to those who received chemotherapy alone. This effect is more pronounced in patients having moderately advanced lymphnode involvement (N1) than in patients without (N0) or more advanced (N2) involvement. Thus, poly(A).poly(U) appears to be an effective agent when used postoperatively with chemotherapy in stomach cancers.

Aged↗
PubMed1990

Effect of polyadenylic.polyuridylic acid on the proliferative responsiveness of mouse thymus and spleen cells.

The effects of polyadenylic.polyuridylic acid [poly(A).poly(U)] on in vitro proliferations of thymus and spleen cells from C57BL/6 mice were investigated. Mice were injected intravenously with 30 micrograms of poly(A).poly(U) or placebo. Two days later, thymus, spleen and peritoneal cells from these mice were prepared and cultured in pooled or non-pooled conditions. Cell proliferations were assessed by the technique of incorporation of tritiated thymidine. It has been revealed that the in vitro proliferations of thymus and spleen cells as well as the productions of interleukin-1 by peritoneal adhering cells and interleukin-2 by spleen cells were significantly enhanced in the cultures of cells from poly(A).poly(U)-treated mice. These enhancing effects were observed only in the cultures of pooled cells from mice whose genetic homogeneity is suspected. Furthermore, thymus cells from poly(A).poly(U)-treated mice acted as strong responder cells but not as stimulators in one way mixed cultures. Thus, the enhanced cellular responsiveness may be mediated by the increased production of cytokines and antigen recognitions of thymus-derived cells following activations via the adjuvant effect of poly(A).poly(U).

Animals↗
PubMed1987

Adjuvant treatment of operable stomach cancer with polyadenylic.polyuridylic acid in addition to chemotherapeutic agents. Differential effect on natural killer cell and antibody-dependent cellular cytotoxicity.

Peripheral blood lymphocytes of operable stomach cancer patients were evaluated sequentially for their natural killer (NK) and antibody-dependent cellular cytotoxicity (ADCC) activities before and after chemotherapy in association with polyadenylic.polyuridylic acid [poly(A).poly(U)]. Their cytotoxicity was measured by 4 h-chromium release assays, using human K562 and sensitized murine L1210 cells as targets for assays of NK and ADCC respectively. The mean NK cytotoxicity of 89 patients before treatment was significantly lower than that of the 18 sex- and age-matched healthy controls, whereas assays of ADCC showed similar levels of cytotoxicity in both groups. Patients who had received postoperative chemotherapy (5 fluorouracil, 12 mg/kg and adriamycin, 40 mg/M2) once, had, 5 days after injection, NK cytotoxicity levels similar to those before treatment. For these patients, an additional administration of poly(A).poly(U) (100 mg) resulted, 2 days later, in a significant increase in the levels of NK cytotoxicity without affecting the levels of ADCC. Repeated injections of poly(A).poly(U) alternated with chemotherapy induced, consistently, exclusive enhancement of NK activity after each injection. These results suggest that the effector cells for NK and ADCC activities are of functionally different cell populations.

Adult↗
PubMed1985

Enhancement of natural killer cell activity and 2-5A synthetase in operable breast cancer patients treated with polyadenylic; polyuridylic acid.

Treatment of operable breast cancer patients with a single injection of 60 mg poly(A); poly(U) (polyadenylic, polyuridylic acid) resulted in an enhancement of natural killer (NK) cell cytotoxicity against human myeloid K562 target cells. Furthermore, the level of 2-5A synthetase in peripheral blood lymphocytes of such patients was increased after the treatment. Both of these effects, measured 24 and 48 hours after the injection of poly(A); poly(U), were statistically significant compared to their respective levels before the treatment. These events, therefore, may be used as markers to monitor the immediate response of patients toward treatment with this synthetic double-stranded RNA.

2',5'-Oligoadenylate Synthetase↗
PubMed1985

A phase I clinical tolerance study of polyadenylic-polyuridylic acid in cancer patients.

Polyadenylic-polyuridylic acid [poly(A) X poly(U)], an immunomodulator, has been shown to have antitumor effects in rodents and in a randomized clinical trial as an adjuvant to surgery in patients with operable breast cancer. The purpose of the present study was to determine the following: (a) clinical tolerance and safety of poly(A) X poly(U) in 13 patients with advanced cancer receiving a single dose of this duplex, using increasing amounts per intravenous injection of 90, 180, 300, and 450 mg; (b) if such high doses increased the level of interferon-mediated protein kinase and enhanced natural killer (NK) cell activity as observed previously with lower doses; and (c) if circulating interferon could be detected. No toxicity was observed in the 13 patients by close observation of clinical parameters, hemogram, and renal and liver functions. Increases of interferon-mediated protein kinase and of NK cell activity were observed, but there was no correlation between the magnitude of the responses and the dose of poly(A) X poly(U). No circulating interferon was detected. We conclude that poly(A) X poly(U) is not toxic in humans, at least up to a dose of 450 mg.

Drug Evaluation↗
PubMed1977

Virus expression in different tissues of normal and tumor-bearing mice inoculated with a murine leukemia virus.

Evolution of virus expression in different lymphoid organs as well as in solid syngeneic tumors of mice inoculated with an MuLV was studied with the aid of in vitro XC co-culture technique. When normal adult mice of strain XLII were inoculated intraperitoneally with a cultured Rauscher virus (RC), the virus could be detected, 10 days after inoculation, only in bone marrow in small amounts and thereafter no virus could be found in any of the organs tested, including bone marrow, spleen, thymus, lymph node and kidney. However, when age- and sex-matched parallel mice bearing syngeneic subcutaneous non-viral tumors were inoculated similarly with the RC virus, the virus could be detected abundantly not only in bone marrow and spleen but also in tumors during the first 3 weeks and even 6 weeks after virus inoculation. Transitional decrease or disappearance of the virus was observed around the 25th-31st day in organs and tumors of the inoculated mice. When the tumor mass was removed from these mice by surgery, the virus disappeared rapidly and definitely from all the organs tested. The virus recovered from in vitro explanted and cultured tumors, taken from mice inoculated with the virus, induced typical lymphoid leukemia in BALB/c mice inoculated as newborns. However, from certain aspects (hypertrophy of the thymus and lymph nodes), this virus was different from the original RC virus.

Animals↗
PubMed1975

Activation of "eclipsed" lymphoid cells from advanced tumor-bearing mice through adoptive transfer to sublethally irradiated syngeneic hosts.

Immunologically inactive or "eclipsed" lymphoid cells from advanced tumor-bearing mice were investigated following their adoptive transfer to irradiated syngeneic hosts. Experiments were performed with two syngeneic tumor-host system: the T5-BALB/c tumor line chronically infected with a low-leukemogenic Rauscher virus variant and the TM1-C3H tumor line developed from a spontaneous C3H/He mouse mammary tumor. In confirmation of our previous data, peritoneal cells (PC) from advanced tumor-bearing mice (EPC) appeared to have lost any capacity to inhibit specifically the growth of corresponding tumor target cells in vitro colony inhibition (CI) tests, whereas PC from immunized mice (IPC) were perfectly active. When these EPC were adoptively transferred by intraperitoneal inoculation into sublethally irradiated (450 R) syngeneic mice in association with respective tumor extracts (TE), the PC from such recipient mice, taken 5 to 13 days later, were nearly as active in in vitro CI tests as were PC from parallel IPC-recipient mice. For this recovery of specific immunological activity following the adoptive transfer of EPC the adjunction of the TE and irradiation of the recipient animals seem important and may be necessary. On the other hand, no specific immunological activity was seen in PC from irradiated mice to which PC from normal mice had been transferred with TE. In addition to the in vitro results, an effect of adoptive transfer of EPC (retardation of tumor growth) was also observed in vivo. It is concluded that the "eclipsed" immunologically inactive state of the EPC in mice bearing advanced tumor is not irreversible and that activation of these cells can occur in vivo under certain conditions helped by the presence of tumor-specific antigenic stimulus.

Animals↗