• Toxicological Research
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• v.8 no.2
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• pp.343-357
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• 1992

Tumor necrosis factor-${\alpha}$(TNF), a polypeptide hormone secreted primarily by activated macrophages, was originally identified on the basis of its ability to cause hemorrhagic necrosis and tumor regression in vivo. Subsequently, TNF has been shown to be an important component of the host responses to infection and cancer and may mediate the wasting syndrome known as cachexia. These systemic actions of TNF are reflected in its diverse effects on target cells in vitro. TNF initiates its diverse cellular actions by binding to specific cell surface receptors. Although TNF receptors have been identified on most of animal cells, regulation of these receptors and the mechanisms which transduce TNF receptor binding into cellular responses are not well understood. Therefore, in the present study, the mechanisms how TNF receptors are being regulated and how TNF receptor binding is being transduced into cellular responses were investigated in rat liver plasma membranes (PM) and ME-180 human cervical carcinoma cell lines. $^{125}I$-TNF bound to high ($K_d=1.51{\pm}0.35nM$)affinity receptors in rat liver PM. Solubilization of PM with 1% Triton X-100 increased both high affinity (from $0.33{\pm}0.04\;to\;1.67{\pm}0.05$ pmoles/mg protein) and low affinity (from $1.92{\pm}0.16\;to\;7.57{\pm}0.50$ pmoles/mg protein) TNF binding without affecting the affinities for TNF, suggesting the presence of a large latent pool of TNF receptors. Affinity labeling of receptors whether from PM or solubilized PM resulted in cross-linking of $^{125}I$-TNF into $M_r$ 130 kDa, 90 kDa and 66kDa complexes. Thus, the properties of the latent TNF receptors were similar to those initially accessible to TNF. To determine if exposure of latent receptors is regulated by TNF, $^{125}I$-TNF binding to control and TNF-pretreated membranes were assayed. Specific binding was increased by pretreatment with TNF (P<0.05), demonstrating that hepatic PM contains latent TNF receptors whose exposure is promoted by TNF. Homologous up-regulation of TNF receptors may, in part, be responsible for sustained hepatic responsiveness during chronic exposure to TNF. As a next step, the post-receptor events induced by TNF were examined. Although the signal transduction pathways for TNF have not been delineated clearly, the actions of many other hormones are mediated by the reversible phosphorylation of specific enzymes or target proteins. The present study demonstrated that TNF induces phosphorylation of 28 kDa protein (p28). Two dimensional soidum dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE) resolved the 28kDa phosphoprotein into two isoforms having pIs of 6.2 and 6.1. The pIs and relative molecular weight of p28 were consistent with those of a previously characterized mRNA cap binding protein. mRNA cap binding proteins are a class of translation initiation factors that recognize the 7-methylguanosine cap structure found on the 5' end of eukaryotic mRNAs. In vitro, these proteins are defined by their specific elution from affinity columns composed of 7-methylguanosine 5'-triphosphate($m^7$GTP)-Sepharose. Affinity purification of mRNA cap binding proteins from control and TNF treated ME-180 cells proved that TNF rapidly stimulates phosphorylation of an mRNA cap binding protein. Phosphorylation occurred in several cell types that are important in vitro models of TNF action. The mRNA cap binding protein phosphorylated in response to TNF treatment was purifice, sequenced, and identified as the proto-oncogene product eukaryotic initiation factor-4E(eIF-4E). These data show that phosphorylation of a key component of the cellular translational machinery is a common early event in the diverse cellular actions of TNF.

• Journal of Life Science
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• v.20 no.6
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• pp.845-852
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• 2010

Our previous study showed that lungs infected by Pseudomonas, a gram-negative bacteria, produce prostaglandin $D_2$ ($PGD_2$) and prostaglandin $E_2$ ($PGE_2$), the two major prostanoids generated by cyclooxygenase-2 (COX-2), and that the ratio of $PGD_2$ and $PGE_2$ can affect the outcome of the bacterial lung infection. In this study, we sought to uncover the mechanism that determines the ratio of $PGD_2$ and $PGE_2$ produced in lung inflammation. When treated with lipopolysaccharide (LPS), primary alveolar macrophages, extracted from mouse lung, more $PGE_2$ was produced than $PGD_2$, whereas MH-S, a murine alveolar macrophage cell line, produced more $PGD_2$ than $PGE_2$ in a similar experiment. Western blot analyses showed that the kinetics of COX-2 expression in both cell types is similar and epigenetic silencing of COX-2 expression did not affect expressions of lipocalin-PGD synthase (L-PGDS) and PGE synthase (mPGES-1), major enzymes synthesizing $PGD_2$ and $PGE_2$ in inflammation, respectively, indicating no effect of COX-2 on expressions of the two enzymes. Expressions of L-PGDS and mPGES-1 were also similar in both cell types, suggesting no effect of the two key enzymes in determining the ratio of $PGD_2$ and $PGE_2$ in these cells. A single intraperitoneal injection of LPS to C57BL/6 mice induced COX-2 expression and, similar to alveolar macrophages, produced more $PGE_2$ than $PGD_2$ in the lung. These results suggest that the differential expressions of $PGD_2$ and $PGE_2$ in the lung reflect those in alveolar macrophages and may not be directly determined by the enzymes responsible for $PGD_2$ and $PGE_2$ synthesis.

• Journal of Life Science
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• v.31 no.11
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• pp.1028-1036
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• 2021

Firefly luciferase (FLuc) can function as an efficient marker in the gene and viral therapies. Nonetheless, its clinical translation has been unaccomplished with the concerns on its exogenous nature and the similarity with human fatty acyl-CoA synthetase. In this study, we aimed to show safety of FLuc by conducting a set of preclinical experiments and a human use. Initially, FLuc permeability across the plasma membrane was investigated by delivering the FLuc-carrying viral vector, OTS-412, or the FLuc recombinant protein. After in vitro infection of OTS-412 into different cancer cell lines, FLuc activity was detected only in the cell lysates, but not in culture media. In addition, recombinant FLuc protein further showed the impermeability against the plasma membrane. Similar result was also observed in the in vivo experiment. After being injected into the VX2 tumor-bearing rabbit, the FLuc exclusively resided within the tumor tissue without being detected in the blood plasma or other organs. Human cancer cell lines originated from various organs were lysed and treated to the FLuc, and none of the human substrates was reactive against the FLuc. As a final step, FLuc recombinant protein was intravenously injected into a human. The luciferase was degraded with the half-life of 20 to 30 minutes in blood, and was untraceable from 1.5 hr after the injection. In addition, the blood plasma was nonresponsive against the fatty acids. Hematological analysis was also comparable between the pre- and post-injection. Altogether, our study collectively demonstrates the safety of the firefly luciferase.

• Journal of Food Hygiene and Safety
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• v.38 no.3
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• pp.123-130
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• 2023

Salmonella spp. are prevalent foodborne pathogens that are infective at relatively low concentrations, thus posing a serious health threat, especially to young children and the elderly. In several countries, the management and regulation of Salmonella spp. in food, including seafood, adhere to a negative detection standard. The risk of infection is particularly high when seafood is consumed raw, which underscores the importance of timely detection of pathogenic microorganisms, such as Salmonella. Accordingly, this study aimed to develop a combined pre-treatment and detection method that includes pre-culture and DNA extraction in order to detect five species of Salmonella at concentrations below 10 CFU/mL in seafood. The effectiveness of the proposed method was assessed in terms of the composition of the enrichment (pre-culture) medium, minimum incubation time, and minimum cell concentration for pathogen detection. Furthermore, a practical DNA extraction method capable of effectively handling high salt conditions was tested and found to be successful. Through polymerase chain reaction, Salmonella spp. Were detected and positively identified in shellfish samples at cell concentrations below 10 CFU/g. Thus, the proposed method, combining sample pre-treatment and cell culture with DNA extraction, was shown to be an effective strategy for detecting low cellular concentrations of harmful bacteria. The proposed methodology is suitable as an economical and practical in situ pre-treatment for effective detection of Salmonella spp. in seafood.

• The Journal of the Korean Society for Microbiology
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• v.14 no.1
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• pp.79-87
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• 1979

The immunosuppressive activity of newcastle disease virus(NDV) and some possible role of interferon(C-IF) in viral suppression of immune response were evaluated by SRBC-induced delayed-type hypersensitivity(DTH), rosette formation in spleen cells, number of lymphocytes in peripheral blood, hemagglutinin and hemolysin response to SRBC in ICR mice sensitized with SRBC. When NDV was inoculated before or after sensitization of mouse with SRBC, virus caused a marked inhibition of DTH, and its depressive effect was dependent on the time of virus inoculation in relation to SRBC sensitization or challenge. Rosette formation of spleen cells was significantly reduced by NDV infection. The degree of the depression of rosette formation was more prominent in mice inoculated before sensitization than after sensitization and could be related to the amount of serum interferon induced by the virus. Humoral response to SRBC of virus infected mouse was significantly depressed when NDV was inoculated 24 or 48 hours before sensitization. However, there was no difference in the response when the virus was inoculated 9 hour before and at the same time of sensitization or even after that. Lymphocytes in peripheral blood of mice were markedly diminished in numbers when NDV was inoculated 48 and 24 hour before sensitization with SRBC, but they were slightly augmented when the virus was inoculated 9 hour before and at the same time of sensitization. When UV-inactivated or heat-inactivated NDV was injected to the mouse at the same time of sensitization with SRBC, DTH and rosette formation of spleen cells were slightly depressed. DTH and rosette formation in mice treated with crude-IF were generally depressed as com pared with those of control mice. These studies suggest that the NDV causes a significant depression of cell-mediated immunity, whereas the humoral immune response is not inhibited markedly, and that the depression of immune response by NDV infection may be caused by interferon produced by NDV and direct viral activity.

• Journal of Preventive Medicine and Public Health
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• v.2 no.1
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• pp.5-22
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• 1969

The urban population of our country is rapidly increasing due to many factors of social structure, and sociologists are predicting that the increase rate of the urban population will be over 50% in 1980's. Above all, the population of the capital city of Seoul, is at present more than four millions. Such centring of people in cities, together with the improvement of the standards of living, caused rapid increase in the amount of fuel consumption, and this consumption of fuels became one of the primary sources of the air pollution in cities. Moreover, the heavy traffic, construction of many tall buildings, and the increasing number of new factories due to the industrial development-all these are contributing to make the matter of air pollution worse and worse in the Metropolitan, whose geographical location is quite unfavorable considered from the view point of air pollution. Most homes in Seoul use briquet as fuel, while oils are used in tall buildings. The CO, $SO_2$, and smoke that come from burning of these fuels are a great threat to the health of the urban population. With the purpose of examining the influence of air pollution upon the public health, written inquiries were made upon respiratory diseases, and the carboxyhemoglobin saturation in the blood was measured to determine whether the air pollution may affect the health of the urban population. Method of Health Examination (1) Investigation of Respiratory Diseases Patients' records were examined to figure out the monthly ambulance rate of respiratory patients to the total number of patients treated. On the other hand, by using the questionnaire form approved by the Medical Research Council's Committee on Research into Chronic Bronchitis, investigators interviewed the examinees and inquired into the respiratory symptoms. (2) Measuring of Carboxyhemoglobin Saturation From the ear lobe of the examinees, with the use of the melangeur for the white blood cell counting, blood was taken, and after diluting it ten times with 0.1% $Na{2}CO_{3}$, again diulting it 20 times with 0.5% $Na_{2}\;CO_{3}$, its absorbancy was measured. The following results are obtained from the investigation. (1) It was found out that 7.7% of the total patients under treatment were suffering from upper respiratory infection, acute or chronic bronchitis, bronchial asthma, pulmonary emphysema and bronchiectasis. Of them all, patients with upper respiratory infection numbered the greatest with 4.8% and patients with acute or chronic bronchitis the next with 2.1%, and their monthly ambulance rate was high from December to February during the winter, and from April to May and from September to October during the changeable seasons. (2) The daily ambulance rate of respiratory patients, it was revealed, had a close connection with the concentration of $SO_2$ and CO in the air. (3) It was found out that men were more subject to respiratory disease than women, and both men and women were more liable to the diseases with the advancing of age. (4) People living at Choong-ku with the heavy traffic and in the industrial zones of Yeungdungpo had high frequency of respiratory symptoms. (5) Considered from the view point of occupations, high frequency was found among those without job, with jobs unknown, merchants and intdustrial workers, whose social status was rather low and traffic policemen who were always exposed to the exhaust gas of cars. As for women, the frequency was detected in the order of those from high to low, housewives who were exposed to briquet gas, women with jobs unknown, women without jobs, whose social status was low. (6) Ex-smokers rather than smokers, of both sexes, had higher frequency. As for men, heavy smokers had high frequency, while in women light smokers had rather high frequency which was presumed to be due to their average old age. (7) Men's average of carboxyhemoglobin saturation was 9.48%, while women's was 11.3%, higher than men's. (p<0.05). Age meant no difference in the case of men, but as for women, the saturation was remarkably high between the ages from 20 to 60. (8) No regional difference was detected in the carboxyhemoglobin saturation. (9) The carboxyhemoglobin saturation was found, in the case of men, in the order of office workers, traffic policemen, students, the unemployed, merchants and industrial workers, drivers; and as for women, the order was housewives, office workers, merchants and industrial workers. (10) No significant correlation was found between the carboxyhemoglobin saturation and the concentration of CO detected in kitchens, or between the carhoxyhemoglobin saturation and the passing of time after exposure to briquet gas. No difference of carboxyhemoglobin saturation was detected between smokers and non-smokers, and the degrees of smoking; only, significant negative correlation was found between the passing of time after smoking and the carboxyhemoglobin saturation. It is ture that air pollution causes or aggravates the respiratory diseases, increases the carboxyhemoglobin saturation in the blood, but what seems to be more hazardous to the health is the air polluted by the briquet gas in the kitchens and on-dol rooms rather than the atmospheric air pollution.

• Korean Journal of Microbiology
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• v.48 no.2
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• pp.109-115
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• 2012

Helicobacter pylori is an important factor of chronic gastritis, digestive ulcer, and stomach cancer. CagL, a virulence factor of H. pylori, is well-known as a pilus protein which acts as adhesion to host cell and a component of Type 4 secretion system. In this study, we evaluated the protective response of recombinant CagL protein (rCagL) using Mongolian gerbil animal model for H. pylori infection. The cagL gene was cloned from 26695 H. pylori followed by over-expression and purification of the protein in E. coli. Mongolian gerbils were immunized with rCagL protein mixed with aluminum adjuvant via intramuscular injections once a week during 4 weeks. At a week after the last immunization, the Mongolian gerbils were administrated with H. pylori 7.13 strain into the stomach and sacrificed to measure antibody titer on rCagL by ELISA and bacterial colonization in the stomach, and to examine the histopathological changes and cytokine expression at 6 week after challenge. Antibody titers on recombinant protein were significantly increased from a week after the first immunization. There was no significant change of the number of bacterial colony between control group and immunized group. The relative stomach weight was significantly decreased in immunized group, but the significant change of histopathological assessment was not observed in the stomach. Cytokine expression such as IL-$1{\beta}$ and KC also was not significantly different between control and immunized groups. These results indicate that rCagL could effectively induce the formation of the specific IgG antibodies. However, bacterial colonization and histopathological lesions could not be inhibited by the immunization in the stomach, indicating not enough protection against H. pylori infection. We consider that along with CagL other adequate antigens could be needed stimulating immune response and inducing protective effects against gastric disease, and also a better adjuvant could be considered.

• Clinical and Experimental Pediatrics
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• v.52 no.1
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• pp.93-98
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• 2009

Purpose : The purpose of this study was to evaluate the clinical characteristics and outcomes of patients with neuroblastoma aged less than 1 year. Methods : From January 1997 to December 2007, 41 patients aged less than 1 year were diagnosed with neuroblastoma. Patients were divided into 3 risk groups according to the stage of the disease and N-myc amplification. Low-risk patients underwent surgery with (stage 2) or without (stage 1) short-term chemotherapy. Intermediate-risk patients underwent chemotherapy and surgery with or without local radiation therapy. High-risk patients underwent chemotherapy, surgery, radiation therapy, and high-dose chemotherapy/autologous stem cell rescue (HDCT/ASCR). Results : While tumor relapse occurred in only 1 patient, 7 patients died of treatment-related toxicities. Causes of treatment- related death included infection during conventional chemotherapy in 5 patients and acute myocarditis during HDCT/ASCR in 2 patients. The overall 5-year survival (${\pm}$ standard error) and 5-year event-free survival (EFS) rates after diagnosis for all 41 patients were $82.8{\pm}5.9%$ and $80.0{\pm}$6.3%$, respectively, with a median follow-up of 58 (9-137) months. The 5-year EFS rates for low-risk, intermediate-risk, and high-risk patients were 100%, $68.4{\pm}10.8%$, and $66.7{\pm}19.3%$, respectively. Conclusion : Increased efforts to reduce infection-associated toxicity deaths during conventional chemotherapy are needed to further improve the survival of patients with neuroblastoma aged less than 1 year.

• Parasites, Hosts and Diseases
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• v.24 no.2
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• pp.109-114
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• 1986

In order to observe the growth and development of Fibricola seoulensis metacercariae, the tadpoles of Rana nigromaculata were experimentally infected with the cercariae. The meta cercariae of various developmental stages were recovered from the tadpoles after 2 to 65 days of infection. They were prepared for morphological observation, and were given orally to mice to observe their infectivity. The following results were obtained. 1. All of the tadpoles exposed to the cercariae were observed to harbour the larvae in their abdominal cavity. 2. The young metacercariae of 2 days after infection were $121.1{\mu}m$ long and $63.3{\mu}m$ wide. They grew linearly for the first 14 days to be $262.0{\mu}m$ long and $166.4{\mu}m$ wide. Thereafter, no more growth recognized until 65 days. 3. The larvae of 2 days old were similar with cercarial body and had 2 suckers, a pharynx, 2 ceca and a primordium of germ cells but no tribocytic organ. On the 8th day, they had tribocytic organ, and their morphology resembled that of mature metacercariae. 4. The metacercariae younger than 10 days could not infect the mice. Only the metacercariae older than 14 days had infectivity. The recovery rates increased by the age of metacercariae from 19.0% in 14 days old to 70.0% in 40 days old. Above findings indicate that the tadpole is indispensable for metacercarial development and it needs at least 2 weeks for maturation. The tadpole is a pivotal host in the life cycle of F. seoulensis for connection between the snail and the frog.

• Pediatric Infection and Vaccine
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• v.5 no.1
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• pp.79-87
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• 1998

Purpose : The P1 protein of Mycoplasma pneumoniae mediates the attachment of the pathogen to its host cell and elicits a strong humoral immune response during infection with this organism. Mycoplasma pneumoniae strains can be classified into two groups(I and II) by PCR method of P1 cytadhesin gene. In this study, we evaluated the prevalence, epidemiological and clinical characteristics of each group. Methods : From 155 patients with Mycoplasma pneumoniae, who admitted to the Department of Pediatrics, Sung-Ae and Kwangmyung Sung-Ae Hospital between November 1996 and October 1997, we collected their throat swabs or nasopharyngeal aspirates for DNA extraction and serum for indirect hemagglutination test of Mycoplasma pneumoniae. The group specific PCR amplification were performed using specific oligonucleotide primers designed for P1 gene genotyping. Results : Group I(137 patients, 88.4%) occurred frequently than group II(18 patients, 11.6%). In both group, the most prevalent season was winter in 1996(Nov. to Dec.) and fall in 1997(Aug. to Oct.) The prevalent age was four to six years old. The number of male was more than female in both group; Group 1(1.2:1), Goup 2(1.6:1). No significant relationship were found between two groups in duration of fever and hospital days(P>0.05). The rate of high antibody titers(>1:5120) was lower in group I(6/137, 4.4%) than group II(2/18, 11.1%). Conclusion : Group I was much more prevalent than group II during 1996~1997 in Korea. There was no difference between two groups in epidemiological and clinical parameters except the rate of high antibody titers. Further follow-up survey will be needed for the epidemiologic and clinical studies of Mycoplasma pneumoniae in Korea.