The hygiene hypothesis, first proposed in 1989, suggested that reduced exposure to infections in early life leads to allergic diseases by the defects in the establishment of immune tolerance. Although many studies provided evidence that some exposure conditions, including family size, antibiotics, probiotics, and viral or bacterial infections, are strongly related to the prevalence of allergic diseases, thereby supporting the hygiene hypothesis, some evidence does not provide acceptable results for the hygiene hypothesis. Further, most studies have focused on patients with asthma or atopic dermatitis, not allergic rhinitis. In this review, we summarize the recent studies for and against the ‘hygiene hypothesis’ and identify causal association with the prevalence of allergic rhinitis.

Allergic rhinitis (AR) is a type of rhinitis accompanied by sensitization to allergens. One of the most clinically important allergens is pollen. Recently, due to climate change and CO 2 air pollution, the flowering period starts earlier and persists longer. In addition, antigenicity due to environmental pollution is also being strengthened. As a result, the sensitization rate to pollen antigens is on the rise. It is known that the prevalence of AR especially caused by pollen is rapidly escalating. Although the causal relationship between pollen exposure and the severity of rhinitis is not precisely established, an association of rhinitis symptoms with the time of pollen scattering exists. In addition, the mixed effect of environmental pollution and pollen may play a role in the development of rhinitis symptoms. Therefore, in order to avoid pollen, it is necessary to constantly improve pollen forecast and minimize the contact with pollen indoors and outdoors. Treatment of AR should be performed according to guidelines. Also, continuous efforts to solve the environmental problems affecting the ecology of pollen are needed.

Among allergic diseases of the Korean pediatric population, allergic rhinitis shows the most rapidly increasing prevalence. Its economic burden is substantial in many Asian countries including South Korea. This investigation of its risk factors aims to reduce the socioeconomic burden by blocking exposure of susceptible individuals to identified causes. However, the risk factors of allergic rhinitis varied considerably depending on the seasons, geographical locations, and populations involved. This review article primarily deals with studies on the risk factors for allergic rhinitis in Korean children that were published during the last 10 years and additionally investigates associated large scale international studies. Our investigation identified several single-nucleotide polymorphisms, inhalant allergens, pollution, tobacco smoke, chemicals, and family affluence as risk factors for allergic rhinitis. In contrast, breastfeeding, older sibling, and microbial diversity were protective factors against allergic rhinitis. This suggests that various genetic and environmental factors might affect the manifestation and presentation of allergic rhinitis complexly. These findings are beneficial as they can provide insights into modifiable risk factors that may hinder the development of allergic rhinitis.

The global worsening of air pollution has decreased the quality of life. Air pollutants can induce oxidative stress, epigenetic changes, and alterations to microRNA expression in the airway and skin, leading to immune dysregulation. Previous epidemiological studies suggest a strong association between outdoor environmental pollution and childhood allergic disease, especially allergic rhinitis (AR). Moreover, traffic-related air pollution has increased the severity and incidence of AR, and heavy traffic has been associated with an increased prevalence of AR. Thus, this review aimed to define outdoor environmental pollution and clarify the mechanisms by which air pollutants aggravate AR. In addition, we performed a systematic review and meta-analysis to summarize the findings of several domestic and international epidemiological and clinical studies about the effects of air pollution on AR in children.

The prevalence of allergic rhinitis in children and adolescents is constantly increasing. However, few studies exist on the relationship between smoking and allergic rhinitis. In addition to conventional cigarettes, electronic and heated cigarettes have recently been introduced, which have several harmful effects. It is hypothesized that smoking and rhinitis are correlated; however, this relationship is complex. Previous studies reported that exposure to smoking during pregnancy is associated with allergic rhinitis development.Unlike the varied results reported in adults, studies on children and adolescents have often correlated direct/indirect smoke with allergic rhinitis, with prolonged exposure being associated with a higher risk of allergic rhinitis, particularly when exposed at an early age. Nonallergic inflammatory reactions and immunoglobulin E-mediated allergic sensitization are assumed to be the underlying mechanisms for the association between allergic rhinitis and smoking. Measures to reduce smoking are warranted to lower the incidence of allergic rhinitis in children and adolescents and to improve their health.

Allergic rhinitis (AR) is one of the most common allergic diseases characterized by stuffy nose, rhinorrhea, sneezing, and itching. Researchers have indicated an increase in the prevalence of AR and younger-age onset during the last few decades. The increasing burden of AR has caused many researchers to investigate time trends of the prevalence of AR and to identify its risk factors. The most commonly used epidemiological studies are cross-sectional ones such as the International Study of Asthma and Allergies in Childhood study and big data from National Health Insurance Service or National Health and Nutrition Examination Survey. However, these studies have many limitations including recall bias, selection bias, and deficit of objective evaluation. Furthermore, crosssectional studies cannot reflect new risk factors associated with the development of AR. New epidemiological studies will be needed to cover genetic factors, environmental changes, microbiomes, and lifestyles that are known to be risk factors for AR. Further studies will be needed to determine the prevalence, natural history, and risk factors of AR in order to advance our understanding of the pathophysiology, prevention, and management of comorbidities of AR.

PURPOSE: Gastric emptying may influence the quality of life of patients who undergo distal gastrectomy. Little is known, however, about gastric emptying after distal gastrectomy. The aim of our study was to investigate gastric emptying patterns after distal gastrectomy. METHODS: This gastric-emptying study investigated patients who underwent distal gastrectomy in the 6 months or more before May 2008 to July 2013 at Chungbuk National University Hospital with a study sample of 205 patients. We analyzed patterns of gastric emptying. RESULTS: Delayed gastric emptying was found in 109 of the 205 patients (53.2%). Food stasis was more frequent in a group with delayed gastric emptying. In multivariate analysis, risk factors for gastroparesis were laparoscopic operation (hazard ratio [HR], 2.731; P = 0.008) and duration of less than 24 months after distal gastrectomy (HR, 2.795; P = 0.001). Delayed gastric emptying tended to decrease with duration of the postoperative period. CONCLUSION: Delayed gastric emptying is common in distal gastrectomy, and is related to laparoscopic operation and duration of the postoperative period. Food stasis was more frequent in a group with delayed gastric emptying.
Chungcheongbuk-do ; Gastrectomy* ; Gastric Emptying* ; Gastroparesis ; Humans ; Multivariate Analysis ; Postoperative Period ; Quality of Life ; Risk Factors ; Stomach Neoplasms

PURPOSE: Gastric emptying may influence the quality of life of patients who undergo distal gastrectomy. Little is known, however, about gastric emptying after distal gastrectomy. The aim of our study was to investigate gastric emptying patterns after distal gastrectomy. METHODS: This gastric-emptying study investigated patients who underwent distal gastrectomy in the 6 months or more before May 2008 to July 2013 at Chungbuk National University Hospital with a study sample of 205 patients. We analyzed patterns of gastric emptying. RESULTS: Delayed gastric emptying was found in 109 of the 205 patients (53.2%). Food stasis was more frequent in a group with delayed gastric emptying. In multivariate analysis, risk factors for gastroparesis were laparoscopic operation (hazard ratio [HR], 2.731; P = 0.008) and duration of less than 24 months after distal gastrectomy (HR, 2.795; P = 0.001). Delayed gastric emptying tended to decrease with duration of the postoperative period. CONCLUSION: Delayed gastric emptying is common in distal gastrectomy, and is related to laparoscopic operation and duration of the postoperative period. Food stasis was more frequent in a group with delayed gastric emptying.
Chungcheongbuk-do ; Gastrectomy* ; Gastric Emptying* ; Gastroparesis ; Humans ; Multivariate Analysis ; Postoperative Period ; Quality of Life ; Risk Factors ; Stomach Neoplasms

BACKGROUND/AIMS: Identifying the impact of a patient's ethnicity on treatment responses in clinical practice may assist in providing individualized treatment regimens for chronic hepatitis C (CHC). The effectiveness of standard peginterferon plus ribavirin therapy and the need for triple combination therapy with protease inhibitors in Koreans remain matters of debate. These issues were investigated in the present study. METHODS: The clinical data of 272 treatment-naive Korean CHC patients who were treated in a community-based clinical trial (Clinical Trial group; n=51) and in clinical practice (Cohort group; n=221), were analyzed and compared. All were treated with standard protocols of peginterferon alfa-2a plus ribavirin therapy. RESULTS: For patients with hepatitis C virus (HCV) genotype 1, the sustained virological response (SVR) rates in the Clinical Trial and Cohort groups were 81% (21/26) and 55% (58/106), respectively, by intention-to-treat (ITT) analysis (P=0.02), and 100% (13/13) and 80% (32/40), respectively, in treatment-adherent patients (P=0.18). For patients with HCV genotype 2, the SVR rates in these two groups were 96% (24/25) and 88% (101/115), respectively, by ITT analysis (P=0.31). Adherence and treatment duration were independent predictors of SVR for genotypes 1 and 2, respectively (P<0.01 for each). Korean patients with CHC achieved high SVR rates with peginterferon alfa-2a plus ribavirin in both the clinical trial and clinical practice settings. CONCLUSIONS: Measures to raise adherence to standard therapy in clinical practice may improve the SVR rates in these patients as effectively as adding protease inhibitors, thus obviating the need for the latter.
Adolescent ; Adult ; Aged ; Antiviral Agents/*therapeutic use ; Asian Continental Ancestry Group ; Cohort Studies ; Drug Therapy, Combination ; Female ; Genotype ; Hepacivirus/genetics ; Hepatitis C, Chronic/*drug therapy ; Humans ; Interferon-alpha/*therapeutic use ; Male ; Middle Aged ; Odds Ratio ; Polyethylene Glycols/*therapeutic use ; Predictive Value of Tests ; RNA, Viral/genetics ; Recombinant Proteins/therapeutic use ; Republic of Korea ; Ribavirin/*therapeutic use ; Treatment Outcome ; Young Adult

Hepatitis B virus X (HBx) protein has been known to play an important role in development of hepatocellular carcinoma (HCC). The aim of this study is to find out whether HBx protein expression affects antiproliferative effect of an epidermal growth factor receptor-tyrosine kinase (EGFR-TK) inhibitor and a MEK inhibitor in HepG2 and Huh-7 cell lines. We established HepG2 and Huh-7 cells transfected stably with HBx gene. HBx protein expression increased pERK and pAkt expression as well as beta-catenin activity in both cells. Gefitinib (EGFR-TK inhibitor) inhibited pERK and pAkt expression and beta-catenin activity in both cells. Selumetinib (MEK inhibitor) reduced pERK level and beta-catenin activity but pAkt expression was rather elevated by selumetinib in these cells. Reduction of pERK levels was much stronger with selumetinib than gefitinib in both cells. The antiproliferative efficacy of selumetinib was more potent than that of gefitinib. However, the antiproliferative effect of gefitinib, as well as selumetinib, was not different between cell lines with or without HBx expression. Signal pathway activation by HBx might not be strong enough to attenuate the antiproliferative effect of EGFR-TK inhibitor. Future experiments are needed to understand the role of HBx protein expression in HCC treatment using molecular targeting agent.
Animals ; Antineoplastic Agents/*pharmacology ; Benzimidazoles/*pharmacology ; Carcinoma, Hepatocellular/*metabolism ; Cell Line, Tumor/drug effects ; Cell Proliferation ; Extracellular Signal-Regulated MAP Kinases/metabolism ; Humans ; Liver Neoplasms/*metabolism ; Mitogen-Activated Protein Kinase Kinases/*antagonists & inhibitors ; Protein Kinase Inhibitors/*pharmacology ; Proto-Oncogene Proteins c-akt ; Quinazolines/*pharmacology ; Receptor, Epidermal Growth Factor/antagonists & inhibitors ; Signal Transduction/*drug effects ; Trans-Activators/*metabolism ; beta Catenin/metabolism