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Human Q fever, a zoonosis caused by Coxiella burnetii, presents with diverse clinical manifestations ranging from mild self-limited febrile illnesses to life-threatening complications such as endocarditis or vascular infection. Although acute Q fever is a benign illness with a low mortality rate, a large-scale outbreak of Q fever in the Netherlands led to concerns about the possibility of blood transfusion-related transmission or obstetric complications in pregnant women. Furthermore, a small minority (< 5%) of patients with asymptomatic or symptomatic infection progress to chronic Q fever. Chronic Q fever is fatal in 5–50% of patients if left untreated. In South Korea, Q fever in humans was designated as a notifiable infectious disease in 2006, and the number of Q fever cases has increased sharply since 2015. Nonetheless, it is still considered a neglected and under-recognized infectious disease. In this review, recent trends of human and animal Q fever in South Korea, and public health concerns regarding Q fever outbreaks are reviewed, and we consider how a One Health approach could be applied as a preventive measure to prepare for zoonotic Q fever outbreaks.
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Objective@#Vortioxetine, a new antidepressant, has been demonstrated to have effects on depression and cognitive function. This study aimed to investigate the anti-depressive efficacy of vortioxetine through a well-designed double-blind, placebo-controlled study in Alzheimer’s disease (AD) patients, and to confirm the presence of secondary benefits, including the improvement of cognitive function and activities of daily living (ADL). @*Methods@#The present study included 100 AD patients with depression who were assigned randomly to 12 weeks of daily treatment with either vortioxetine or placebo. The primary efficacy measure was the change in the Cornell Scale for Depression in Dementia score from baseline to 12 weeks. Several secondary efficacy measures were evaluated, including the Korean version of the Short form of Geriatric Depression Scale and several cognitive function domains. The safety and tolerability of vortioxetine were also assessed. We performed modified intention-to-treat analysis using mixed modeling (the Mixed Models for Repeated Measures). @*Results@#There was no statistically significant difference between the two groups in terms of depressive symptoms, cognitive functions, and ADL. Further, the percentage of adverse events and drug discontinuation between the vortioxetine and placebo groups was similar. @*Conclusion@#Our results suggest that vortioxetine might not be effective in reducing depressive symptoms or cognitive impairment in AD patients with depression. However, general drug tolerance and patient safety were similar to those of placebo. Thus, additional studies are needed to replicate the effectiveness and tolerability of vortioxetine in AD patients with depression.
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Background@#Iliotibial band friction syndrome (ITBFS) is a common disorder of the lateral knee. Previous research has reported that the iliotibial band (ITB) thickness (ITBT) is correlated with ITBFS, and ITBT has been considered to be a key morphologic parameter of ITBFS. However, the thickness is different from inflammatory hypertrophy. Thus, we made the ITB cross-sectional area (ITBCSA) a new morphological parameter to assess ITBFS. @*Methods@#Forty-three patients with ITBFS group and from 43 normal group who underwent T1W magnetic resonance imaging were enrolled. The ITBCSA was measured as the cross-sectional area of the ITB that was most hypertrophied in the magnetic resonance axial images. The ITBT was measured as the thickest site of ITB. @*Results@#The mean ITBCSA was 25.24 ± 6.59 mm 2 in the normal group and 38.75 ± 9.11 mm 2 in the ITBFS group. The mean ITBT was 1.94 ± 0.41 mm in the normal group and 2.62 ± 0.46 mm in the ITBFS group. Patients in ITBFS group had significantly higher ITBCSA (P < 0.001) and ITBT (P < 0.001) than the normal group. A receiver operator characteristic curve analysis demonstrated that the best cut-off value of the ITBT was 2.29 mm, with 76.7% sensitivity, 79.1% specificity, and area under the curve (AUC) 0.88. The optimal cut-off score of the ITBCSA was 30.66 mm 2 , with 79.1% sensitivity, 79.1% specificity, and AUC 0.87. @*Conclusions@#ITBCSA is a new and sensitive morphological parameter for diagnosing ITBFS, and may even be more accurate than ITBT.
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During the 2019 domestic measles outbreak in Korea, measles occurred in healthcare workers with two doses of the measles, mumps and rubella vaccine, and the strict application of the Occupational Safety and Health Act required medical institutions to identify healthcare workers' immunity to measles and vaccinate the susceptible pockets. In response to the frontline medical institutions' request to review the measles recommendations and guidelines, the Korean Society of Infectious Diseases held a roundtable discussion on the causes of measles outbreak, timing of vaccinations, antibody tests, and booster vaccinations for healthcare workers, and financial support from the government and municipality as well as response strategies against the outbreak in healthcare settings. In Korea, the seroprevalence of measles is decreasing in the vaccine-induced immunity group during the maintenance of measles elimination over several years. The susceptible group against measles is in their 20s and 30s, and this may be because of waning immunity rather than nonresponse considering Korea's vaccine policy. The risk of measles nosocomial infection from community increases as these susceptible pockets actively engage in medical institutions.Thus, data on the immunity of low seroprevalence group in Korea are needed, further discussion is needed on the booster vaccination based on the data. Especially, antibody testing and vaccination in healthcare workers may be necessary to prevent the spread of measles in medical insutitutions, and further discussion is needed regarding specific testing methods, and the timing and frequency of test and vaccination.
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Background@#Iliotibial band friction syndrome (ITBFS) is a common disorder of the lateral knee. Previous research has reported that the iliotibial band (ITB) thickness (ITBT) is correlated with ITBFS, and ITBT has been considered to be a key morphologic parameter of ITBFS. However, the thickness is different from inflammatory hypertrophy. Thus, we made the ITB cross-sectional area (ITBCSA) a new morphological parameter to assess ITBFS. @*Methods@#Forty-three patients with ITBFS group and from 43 normal group who underwent T1W magnetic resonance imaging were enrolled. The ITBCSA was measured as the cross-sectional area of the ITB that was most hypertrophied in the magnetic resonance axial images. The ITBT was measured as the thickest site of ITB. @*Results@#The mean ITBCSA was 25.24 ± 6.59 mm 2 in the normal group and 38.75 ± 9.11 mm 2 in the ITBFS group. The mean ITBT was 1.94 ± 0.41 mm in the normal group and 2.62 ± 0.46 mm in the ITBFS group. Patients in ITBFS group had significantly higher ITBCSA (P < 0.001) and ITBT (P < 0.001) than the normal group. A receiver operator characteristic curve analysis demonstrated that the best cut-off value of the ITBT was 2.29 mm, with 76.7% sensitivity, 79.1% specificity, and area under the curve (AUC) 0.88. The optimal cut-off score of the ITBCSA was 30.66 mm 2 , with 79.1% sensitivity, 79.1% specificity, and AUC 0.87. @*Conclusions@#ITBCSA is a new and sensitive morphological parameter for diagnosing ITBFS, and may even be more accurate than ITBT.
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During the 2019 domestic measles outbreak in Korea, measles occurred in healthcare workers with two doses of the measles, mumps and rubella vaccine, and the strict application of the Occupational Safety and Health Act required medical institutions to identify healthcare workers' immunity to measles and vaccinate the susceptible pockets. In response to the frontline medical institutions' request to review the measles recommendations and guidelines, the Korean Society of Infectious Diseases held a roundtable discussion on the causes of measles outbreak, timing of vaccinations, antibody tests, and booster vaccinations for healthcare workers, and financial support from the government and municipality as well as response strategies against the outbreak in healthcare settings. In Korea, the seroprevalence of measles is decreasing in the vaccine-induced immunity group during the maintenance of measles elimination over several years. The susceptible group against measles is in their 20s and 30s, and this may be because of waning immunity rather than nonresponse considering Korea's vaccine policy. The risk of measles nosocomial infection from community increases as these susceptible pockets actively engage in medical institutions.Thus, data on the immunity of low seroprevalence group in Korea are needed, further discussion is needed on the booster vaccination based on the data. Especially, antibody testing and vaccination in healthcare workers may be necessary to prevent the spread of measles in medical insutitutions, and further discussion is needed regarding specific testing methods, and the timing and frequency of test and vaccination.
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The aim of this study was to compare and quantify the spatiotemporal and gait parameters obtained by foot pressure analysis during the gait in a group of Parkinson's disease (PD) patients compared with other Parkinsonism diseases, especially multiple system atrophy (MSA). Thirty-seven out of ninety-three patients who visited the center of neurology or rehabilitation with features of Parkinsonism were recruited. Spatiotemporal gait parameters were collected using gait analysis system. The results did not differ in terms of the stride length, step width, double stance phase, stride time, cadence, velocity, gait line and single support line differences, anterior-posterior position of center of pressure, and maximal gait line velocity; the lateral symmetry showed a significant difference between the PD and the MSA groups (p < 0.05). The study evaluated the differences in terms of spatiotemporal parameters between the PD and MSA along with other Parkinsonism diseases; it showed that the PD patients had a gait tendency to deviate laterally compared to the MSA patients. The result suggests conducting the gait foot pressure analysis might help distinguish PD from other Parkinsonism diseases in early stage, aiding the early decision for the treatment plans.
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Humans , Foot , Gait , Multiple System Atrophy , Neurology , Parkinson Disease , Parkinsonian Disorders , RehabilitationABSTRACT
PURPOSE: The purpose of this study was to test a hypothesis explaining direct and indirect relationships among the factors affecting self-care behaviors of kidney transplant patients, based on self-determination theory. METHODS: Data were collected from 222 outpatients with kidney transplantation. The endogenous and exogenous variables of the hypothetical model consisted of healthcare provider's autonomy support, duration after kidney transplantation, basic psychological need satisfaction, autonomous and controlled motivation, depression, and self-care behaviors. Collected data were analyzed using SPSS/WIN 24.0 and AMOS 24.0. RESULTS: The hypothetical model demonstrated a good fit: RMSEA=.06, SRMR=.04, TLI=.94, CFI=.97. Statistically significant explanatory variables for the self-care behaviors of kidney transplant patients were duration after transplantation and basic psychological need satisfaction. Healthcare provider's autonomy support was indirectly significant, while autonomous motivation, controlled motivation and depression were not statistically significant for self-care behaviors. The variables accounted for 59.5% of the self-care behaviors of kidney transplant patients. CONCLUSION: It is necessary to develop an autonomy support program for healthcare providers to enhance the self-care behaviors of kidney transplant patients. Preventing the deterioration of self-care behaviors will be possible by conducting this program at one year and six years post-transplantation. In addition, the results suggest the need to developing personalized autonomy support programs for healthcare providers that can meet the basic psychological need satisfaction of kidney transplant patients.
Subject(s)
Humans , Delivery of Health Care , Depression , Health Behavior , Health Personnel , Kidney Transplantation , Kidney , Motivation , Outpatients , Self CareABSTRACT
To develop the large scale serological assay for severe fever with thrombocytopenia syndrome virus (SFTSV) infection, we evaluated two different enzyme-linked immunosorbent assay (ELISA) methods using nucleocapsid protein (NP) and Gn proteins of CB1 (genotype B) SFTSV strains. The NP-based ELISA tests showed more sensitive with broad cross-reactivity between two different genotype A and B strains compared with those of Gn-based ELISA tests. However, Gn-based ELISA showed more genotype specificity and specificity. These result suggested that NP-based ELISA test could be applicable for general sero-prevalence studies of SFTSV infections, while Gn-based ELISA could be applicable for a certain specific genotype sero-prevalence study.
Subject(s)
Diagnosis , Enzyme-Linked Immunosorbent Assay , Fever , Genotype , Nucleocapsid Proteins , Sensitivity and Specificity , ThrombocytopeniaABSTRACT
BACKGROUND: The converging epidemics of tuberculosis (TB) and end-stage renal disease (ESRD) have generated a significant public health burden, however, previous studies have been limited to a small number of patients. This nationwide cohort study aimed to assess the rate of developing active TB among patients receiving dialysis for ESRD. METHODS: The Korean national health insurance database was used to identify patients receiving dialysis for new-onset ESRD during 2004–2013, who were propensity score matched to an equivalent number of non-dialysis subjects from the general population. The incidences of active TB in the ESRD and control cohorts were calculated for 2004–2013, and multivariable Cox proportional hazards model was used to evaluate the ESRD-related risk of active TB. RESULTS: During 2004–2013, 59,584 patients received dialysis for newly diagnosed ESRD. In the dialysis and control cohorts, 457 (0.8%) and 125 (0.2%) cases of active TB were detected, respectively. Patients with ESRD were associated with a significantly higher risk of active TB compared to the controls (incidence rate ratio, 4.80). The ESRD cohort had an independently elevated risk of active TB (adjusted hazard ratio, 4.39; 95% confidence interval, 3.60–5.37). CONCLUSION: We found that patients receiving dialysis for ESRD had an elevated risk of active TB. These results highlight the need for detailed and well-organised guidelines for active TB screening among patients with ESRD.
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Humans , Cohort Studies , Dialysis , Incidence , Kidney Failure, Chronic , Korea , Mass Screening , National Health Programs , Propensity Score , Proportional Hazards Models , Public Health , Renal Insufficiency, Chronic , TuberculosisABSTRACT
Since 2013, the Hospital-based Influenza Morbidity and Mortality (HIMM) surveillance system began a H7N9 influenza surveillance scheme for returning travelers in addition to pre-existing emergency room (ER)-based influenza-like illness (ILI) surveillance and severe acute respiratory infection (SARI) surveillance. Although limited to eastern China, avian A/H7N9 influenza virus is considered to have the highest pandemic potential among currently circulating influenza viruses. During the study period between October 1st, 2013 and April 30th, 2016, 11 cases presented with ILI within seven days of travel return. These patients visited China, Hong Kong, or neighboring Southeast Asian countries, but none of them visited a livestock market. Seasonal influenza virus (54.5%, 6 among 11) was the most common cause of ILI among returning travelers, and avian A/H7N9 influenza virus was not detected during the study period.
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Humans , Asian People , China , Emergency Service, Hospital , Hong Kong , Influenza A Virus, H7N9 Subtype , Influenza, Human , Livestock , Mortality , Orthomyxoviridae , Pandemics , SeasonsABSTRACT
Although Q fever is an important zoonotic infection with a worldwide distribution, no human isolates of Coxiella burnetii have been identified in Korea. For the first time, we identified the nucleotide sequence of C. burnetii from a 32-year-old man with an acute febrile illness in Korea. Diagnosis of acute Q fever was confirmed by seroconversion using indirect immunofluorescence antibody assays. Phylogenetic analysis demonstrated high sequence similarity (99.6%–100%) with C. burnetii 16S rRNA sequences identified from the reservoir. These results are the first genetic analysis of C. burnetii in a human case of Q fever in Korea.
Subject(s)
Adult , Humans , Base Sequence , Coxiella burnetii , Coxiella , Diagnosis , Fluorescent Antibody Technique, Indirect , Korea , Q Fever , Seroconversion , ZoonosesABSTRACT
We reported on a 60-year-old man presenting lymphedema of both lower extremities and scrotum for 3 years with unknown cause. We took a computed tomography scan of the lower extremities as a follow-up. There were diffuse subcutaneous edema in both lower extremities and multiple enlarged lymph nodes along the para-aortic and bilateral inguinal areas. For further evaluation, biopsy of an enlarged inguinal lymph node was taken, yielding a diagnosis of primary amyloidosis. A treatment of chemotherapy for amyloidosis was recommended for him. To our knowledge, this is the first report of lymphedema presenting with primary amyloidosis in Asia. This case suggests that primary amyloidosis could be one of the differential diagnoses in patients with lymphedema in the lower extremities.
Subject(s)
Humans , Middle Aged , Amyloidosis , Asia , Biopsy , Diagnosis , Diagnosis, Differential , Drug Therapy , Edema , Follow-Up Studies , Lower Extremity , Lymph Nodes , Lymphedema , ScrotumABSTRACT
BACKGROUND: The World Health Organization recommends the surveillance of influenza-like illness (ILI) and severe acute respiratory infection (SARI) to respond effectively to both seasonal influenza epidemics and pandemics. In Korea, the “Hospital-based Influenza Morbidity and Mortality (HIMM)” surveillance system has been operated to monitor ILI and SARI occurrences. MATERIALS AND METHODS: A multi-center prospective observational study was conducted. Adult patients with acute respiratory infection (ARI) were enrolled during the 2011-12, 2012-2013, and 2013-2014 influenza seasons at the 10 university hospitals using the HIMM surveillance system. With respect to SARI and pneumonia development, risk profiles were analyzed in patients with ARI in Korea. RESULTS: A total of 5,459 cases were eligible for this analysis. Among 5,459 cases with ARI, 2,887 cases (52.9%) were identified that they had influenza infection. Among enrolled cases, 750 cases belonged to the SARI group, while 4,709 cases belonged to the non-SARI group. With respect to pneumonia development, 317 cases were accompanied by pneumonia, and 5,142 cases were not. Multivariate analyses revealed that the following factors were associated with an increased risk of SARI: Old age (≥65 years) (odds ratio [OR] 2.69, 95% confidence interval [CI] 2.2-3.32), chronic heart disease (CHD) (OR 2.24, 95% CI 1.68-2.98), cerebrovascular disease (CVD) (OR 1.49, 95% CI 1.05-2.10), chronic obstructive pulmonary disease (COPD) (OR 2.34, 95% CI 1.48-3.69), asthma (OR 2.33, 95% CI 1.62-3.36), chronic kidney disease (CKD) (OR 2.62, 95% CI 1.73-3.99), chronic liver disease (OR 1.71, 95% CI 1.04-2.81), and autoimmune diseases (OR 2.53, 1.57-4.08). Multivariate analyses revealed that the following factors were independent risk factors for pneumonia development: Old age (≥65 years) (OR 5.71, 95% CI 4.10-7.94), CHD (OR 1.54, 95% CI 1.07-2.22), COPD (OR 2.34, 95% CI 1.48-3.69), asthma (OR 2.33, 95% CI 1.62-3.36), CKD (OR 2.62, 95% CI 1.73-3.99), immunocompromised conditions (OR 3.12, 95% CI 1.47-6.62), and autoimmune diseases (OR 3.35, 95% CI 1.79-6.27). The risk of SARI and pneumonia was increased by the number of concurrent chronic medical conditions. CONCLUSION: The risk of SARI and pneumonia development among adult patient with ARI was significantly increased by the presence or number of concurrent chronic medical conditions in Korea.
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Adult , Humans , Asthma , Autoimmune Diseases , Cerebrovascular Disorders , Heart Diseases , Hospitalization , Hospitals, University , Influenza, Human , Korea , Liver Diseases , Mortality , Multivariate Analysis , Observational Study , Pandemics , Pneumonia , Prospective Studies , Pulmonary Disease, Chronic Obstructive , Renal Insufficiency, Chronic , Risk Factors , Seasons , World Health OrganizationABSTRACT
BACKGROUND: A Middle East Respiratory Syndrome coronavirus (MERS-CoV) outbreak in South Korea in 2015 started by a single imported case and was amplified by intra- and inter-hospital transmission. We describe two hospital outbreaks of MERS-CoV infection in Daejeon caused by a single patient who was infected by the first Korean case of MERS. MATERIALS AND METHODS: Demographic and clinical information involving MERS cases in the Daejeon cluster were retrospectively collected and potential contacts and exposures were assessed. The incubation periods and serial intervals were estimated. Viral RNAs were extracted from respiratory tract samples obtained from the index case, four secondary cases and one tertiary case from each hospital. The partial S2 domain of the MERS-CoV spike was sequenced. RESULTS: In Daejeon, a MERS patient (the index case) was hospitalized at Hospital A in the first week of illness and was transferred to Hospital B because of pneumonia progression in the second week of illness, where he received a bronchoscopic examination and nebulizer therapy. A total of 23 secondary cases (10 in Hospital A and 13 in Hospital B) were detected among patients and caregivers who stayed on the same ward with the index case. There were no secondary cases among healthcare workers. Among close hospital contacts, the secondary attack rate was 15.8% (12/76) in Hospital A and 14.3% (10/70) in Hospital B. However, considering the exposure duration, the incidence rate was higher in Hospital B (7.7/100 exposure-days) than Hospital A (3.4/100 exposure-days). In Hospital B, the median incubation period was shorter (4.6 days vs. 10.8 days), the median time to pneumonia development was faster (3 days vs. 6 days) and mortality was higher (70% vs. 30.8%) than in Hospital A. MERS-CoV isolates from 11 cases formed a single monophyletic clade, with the closest similarity to strains from Riyadh. CONCLUSION: Exposure to the MERS case in the late stage (2nd week) of diseases appeared to increase the risk of transmission and was associated with shorter incubation periods and rapid disease progression among those infected. Early detection and isolation of cases is critical in preventing the spread of MERS in the hospital and decreasing the disease severity among those infected.
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Humans , Caregivers , Coronavirus Infections , Delivery of Health Care , Disease Outbreaks , Disease Progression , Incidence , Korea , Middle East Respiratory Syndrome Coronavirus , Middle East , Mortality , Nebulizers and Vaporizers , Pneumonia , Respiratory System , Retrospective Studies , RNA, ViralABSTRACT
BACKGROUND: From May to July 2015, the Republic of Korea experienced the largest outbreak of Middle East respiratory syndrome (MERS) outside the Arabian Peninsula. A total of 186 patients, including 36 deaths, had been diagnosed with MERS-coronavirus (MERS-CoV) infection as of September 30th, 2015. MATERIALS AND METHODS: We obtained information of patients who were confirmed to have MERS-CoV infection. MERS-CoV infection was diagnosed using real-time reverse-transcriptase polymerase chain reaction assay. RESULTS: The median age of the patients was 55 years (range, 16 to 86). A total of 55.4% of the patients had one or more coexisting medical conditions. The most common symptom was fever (95.2%). At admission, leukopenia (42.6%), thrombocytopenia (46.6%), and elevation of aspartate aminotransferase (42.7%) were observed. Pneumonia was detected in 68.3% of patients at admission and developed in 80.8% during the disease course. Antiviral agents were used for 74.7% of patients. Mechanical ventilation, extracorporeal membrane oxygenation, and convalescent serum were employed for 24.5%, 7.1%, and 3.8% of patients, respectively. Older age, presence of coexisting medical conditions including diabetes or chronic lung disease, presence of dyspnea, hypotension, and leukocytosis at admission, and the use of mechanical ventilation were revealed to be independent predictors of death. CONCLUSION: The clinical features of MERS-CoV infection in the Republic of Korea were similar to those of previous outbreaks in the Middle East. However, the overall mortality rate (20.4%) was lower than that in previous reports. Enhanced surveillance and active management of patients during the outbreak may have resulted in improved outcomes.
Subject(s)
Humans , Antiviral Agents , Aspartate Aminotransferases , Coronavirus Infections , Disease Outbreaks , Dyspnea , Extracorporeal Membrane Oxygenation , Fever , Hypotension , Leukocytosis , Leukopenia , Lung Diseases , Middle East Respiratory Syndrome Coronavirus , Middle East , Mortality , Pneumonia , Polymerase Chain Reaction , Republic of Korea , Respiration, Artificial , ThrombocytopeniaABSTRACT
Pneumocystis jirovecii pneumonia (PJP) in patients with HIV infection can, in rare cases, present with pulmonary nodules that histologically involve granulomatous inflammation. This report describes an intriguing case of granulomatous PJP with pulmonary nodules after commencing antiretroviral therapy (ART) in an HIV-infected patient without respiratory signs or symptoms. Diagnosis of granulomatous PJP was only achieved through thoracoscopic lung biopsy. This case suggests that granulomatous PJP should be considered in the differential diagnosis of pulmonary nodules in HIV-infected patients for unmasking immune reconstitution inflammatory syndrome manifestation after initiation of ART.
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Infectious diseases have historically resulted in suspended or cancelled military operations. Vaccination for disease prevention is a critical component of the military's force readiness doctrine. Until recently, Korea had not recognized the importance of vaccinating military personnel. However, a 2011 meningococcal disease outbreak at an army recruit training center led to dramatic changes in the paradigm of traditional medical practice in the Korean armed forces. A new vaccination policy was formed by a 2012 Military Healthcare Service Act. Since then, Neisseria meningitidis, hepatitis A, and measles-mumps-rubella vaccines have been routinely administered to all new recruits early in basic training to ensure protection against these diseases. All active-duty soldiers also receive seasonal influenza vaccination annually. Despite quantitative improvements in vaccination policies, several instances of major infectious diseases and adverse vaccine reactions have threatened soldier health. In the future, vaccination policies in the Korean armed forces should be based on epidemiologic data and military medical research for vaccine use and safety management.
Subject(s)
Humans , Health Policy , Hepatitis A Vaccines/immunology , Influenza Vaccines/immunology , Measles-Mumps-Rubella Vaccine/immunology , Meningococcal Vaccines/immunology , Military Personnel , Republic of Korea , VaccinationABSTRACT
This study was designed to examine the effects of histamine on gastric motility and its specific receptor in the circular smooth muscle of the human gastric corpus. Histamine mainly produced tonic relaxation in a concentration-dependent and reversible manner, although histamine enhanced contractility in a minor portion of tissues tested. Histamine-induced tonic relaxation was nerve-insensitive because pretreatment with nerve blockers cocktail (NBC) did not inhibit relaxation. Additionally, K+ channel blockers, such as tetraethylammonium (TEA), apamin (APA), and glibenclamide (Glib), had no effect. However, N(G)-nitro-L-arginine methyl ester (L-NAME) and 1H-(1,2,4)oxadiazolo (4,3-A) quinoxalin-1-one (ODQ), an inhibitor of soluble guanylate cyclase (sGC), did inhibit histamine-induced tonic relaxation. In particular, histamine-induced tonic relaxation was converted to tonic contraction by pretreatment with L-NAME. Ranitidine, the H2 receptor blocker, inhibited histamine-induced tonic relaxation. These findings suggest that histamine produced relaxation in circular smooth muscle of human gastric smooth muscle through H2 receptor and NO/sGC pathways.