Development of a real-time impedance matching system for ion cyclotron resonance heating in experimental advanced superconducting tokamak

To achieve stable operation of an ion cyclotron resonance heating (ICRH) system in the Experimental Advanced Superconducting Tokamak (EAST), a real-time impedance matching system needs to be established to respond to antenna load variation during long pulse discharges. A new impedance matching method based on capacitors was proposed in this study. By considering the reflected voltage of the transmission line as the feedback parameter, the real-time impedance-matching system can quickly control the motors based on a programmable logic controller to determine the minimum reflection voltage. A real-time impedance matching system was successfully used on the test platform in the laboratory and on the ICRH system in EAST. A significant result is that we can match the variable impedance within 1 s by suitably adjusting the motor controller to ensure high-power and long-pulse operation of the ICRH system to satisfy the requirements of the EAST experiment.

[Risk factors for the occurrence of laryngopharyngeal reflux disease in the aged and the clinical characteristics of patients complicated with pneumonia]

Objective: To investigate the risk factors for the occurrence of laryngopharyngeal reflux disease in the aged, and to analyze the characteristics of patients with pneumonia. Methods: Patients who underwent 24-hour laryngopharyngeal pH monitoring from June 2020 to July 2022 and the positive patients of those who underwent 24-hour esophageal pH monitoring from March 2017 to July 2022 at the Second Medical Center of the PLA General Hospital were enrolled retrospectively. Positive results of 24-hour laryngopharyngeal reflux monitoring were in the laryngopharyngeal reflux group, and the negative results were in the non-laryngopharyngeal reflux group. Patients with pneumonia and simple gastroesophageal reflux disease were in the esophageal reflux pneumonia group, and patients with pneumonia and simple laryngopharyngeal reflux disease were in the laryngopharyngeal reflux pneumonia group. Patients' basic data, co-morbidities, drug use and relevant examination and test results were collected. Multivariate logistic regression analysis was used to analyze the risk factors of laryngopharyngeal reflux disease in the aged and its relationship with pneumonia. Results: A total of 80 patients with 24-hour laryngopharyngeal pH monitoring were enrolled finally, including 34 cases, all male, aged (73±12) years, in the laryngopharyngeal reflux group, and 46 cases [44 males, 2 females, aged (78±11) years] in the non-laryngopharyngeal reflux group. Multivariate logistic regression analysis showed that the risk factors of laryngopharyngeal reflux disease in the aged included age ≤70 years (OR=13.07, 95%CI: 2.53-67.68), body mass index (BMI) (OR=1.37, each additional 1 kg/m2, 95%CI: 1.03-1.83), use of antipsychotic drugs (OR=8.00, 95%CI: 1.40-45.73) and calcium channel blockers (OR=5.27, 95%CI: 1.13-24.53) (all P<0.05). The protective factors of the laryngopharyngeal reflux disease in the aged included antacids (OR=0.19, 95%CI: 0.04-0.90, P=0.035). The incidence of pneumonia was higher in the laryngopharyngeal reflux group compared with the non-laryngopharyngeal reflux group [44.1% (15/34) vs 21.7% (10/46), P=0.033]. The esophageal reflux pneumonia group included 32 cases [31 males and 1 females, aged (84±12) years]. The laryngopharyngeal reflux pneumonia group included 15 cases [ 15 males, aged (79±11) years]. Compared to the patients in the laryngopharyngeal reflux pneumonia group, the patients in the esophageal reflux pneumonia group had a longer course of antibiotics [(27.7±27.0) vs (14.6±13.9) days, P=0.034], a higher frequency of seizure frequency [(4.3±3.0) vs (1.8±1.5) times/year, P<0.001] and a higher maximal body temperature [(38.2±0.9) vs (37.6±1.1) ℃, P=0.037]. Conclusions: The risk factors of laryngopharyngeal reflux disease in the aged included age ≤70 years, higher BMI, use of antipsychotic drugs and calcium channel blockers. The incidence of pneumonia in laryngopharyngeal reflux disease is higher, but the condition of pneumonia is milder.

[Application of omics in the diagnosis of metabolic dysfunction-associated fatty liver disease]

Metabolic dysfunction-associated fatty liver disease (MAFLD) is the most common chronic liver disease worldwide, and the risk of all-cause and liver-related mortality significantly increases with the degree of fibrosis. Early diagnosis of MAFLD and its degree of liver fibrosis are of great significance, so it is particularly important to find an accurate and simple, non-invasive diagnostic method. In recent years, high-throughput omics technology has developed rapidly and played an important role in the non-invasive diagnosis and prediction of fibrosis degree in MAFLD. This article summarizes the application progress of genomics, epigenomics, transcriptomics, proteomics, metabolomics, microbiomics, radiomics, and the combination of multi-omics for the diagnosis of MAFLD disease.

Concurrent Chemoradiotherapy plus Programmed Death-1 (PD-1) Blockade for Locally Advanced Cervical Cancer: Preliminary Results of a Single-Arm, Open-Label, Phase II Trial

PURPOSE/OBJECTIVE(S)

This study aims to assess the anti-tumor activity and safety of concurrent chemoradiotherapy plus PD-1 blockade in patients with locally advanced cervical cancer.

MATERIALS/METHODS

This is a single-arm, open-label, prospective phase II study. The key inclusion criteria were treatment-naive patients aged 18-75 years with stage II A2-IVA (FIGO 2018) locally advanced cervical cancer. All patients were treated with concurrent chemoradiotherapy including 2 cycle cisplatin (75mg/m2, for three days, every 3 weeks[Q3W]), nedaplatin or carboplatin can be selected for patients who can't tolerate cisplatin. After CCRT, patients achieving complete response (CR), partial responses(PR), stable disease(SD) received adjuvant chemotherapy (docetaxel 75 mg/m2 day 1+ cisplatin DDP 25 mg/m2 day 1-3, Q3W) for 2 cycle. PD-1 blockade Sintilimab and Tislelizumab was administered intravenously at 200 mg every 3 weeks up to 1 year or until disease progression, unacceptable toxicity, or withdrawal of consent. The primary endpoint was objective response rate (ORR) assessed by investigators per Response Evaluation Criteria In Solid Tumours (RECIST) version 1.1. Secondary endpoints were the 12, 24-month overall survival (OS) rates, the 12, 24-month disease free survival (DFS) rates and safety.

RESULTS

From February 2020 to June 2022, a total of 15 patients was enrolled. Median age was 57 years (range, 36-74 years). Stage IIA1 was documented in 2 patients, stage IIA2 in two patients, stage IIIA in one patient, stage IIIC1 in eight patients, and stage IVA in two patients. And 66.7% (10/15) of patients had Metastatic lymph node. Four patients received adjuvant chemotherapy. The ORR was 100%, with 4 patients achieving CR and 11 PR. The 12 and 24-month OS rates are 93.3% and 84%, the 12 and 24-month DFS rates are 86% and 75.4%, respectively. Treatment-related adverse events (TRAEs) occurred in 86.7% (13/15) of patients. Grade 3 TRAEs are leukocyte (n = 1), thrombocytopenia (n = 1), hepatitis (n = 1), skin reaction (n = 1). No treatment-related deaths occurred. And IFN-γ was significantly elevated after radiotherapy (p = 0.0073).

CONCLUSION

Concurrent chemoradiotherapy plus PD-1 blockade showed promising antitumor activity and manageable toxicities in patients with locally advanced cervical cancer. Long-term outcomes are still pending to further evaluate their therapeutic effects. (ChiCTR2000032856).

[Analysis of drug resistance pattern and genes of Salmonella.spp isolated from human infections in Anhui Province]

Objective: To investigate the drug resistance pattern and drug resistance genotypes of Salmonella. spp isolated from fecal specimens and anal swabs of diarrhea cases in Anhui Province. Methods: The 149 strains of Salmonella.spp isolated from feces and anal swabs of diarrhea cases in Anhui Province from April to October 2017 were selected. The serotypes of Salmonella.spp were identified by slide agglutination. The susceptibility of all strains to 14 antibiotics were determined by micro-broth dilution method. Sixty of the cephalosporin-resistant antibiotics were selected. The β-lactamase encoding genes bla(TEM), bla(SHV), bla(OXA-1), bla(OXA-2), bla(PER), bla(CMY), bla(CTX-M), and colistin resistance genes mcr-1 and mcr-2 were performed using the multi-PCR method. Results: Of the 149 diarrhea cases, the median (P(25), P(75)) of the age was 5.0 (1.1, 38.5). The 92 of them were male and 54.4% were children. Of the 149 strains of Salmonella.spp, 105 strains had different degrees of resistance to 13 antibiotics other than imipenem. The resistance rate of ampicillin was 55.0% (82/149), which was the highest. 53.0% strains (79 strains) were multidrug resistant, main of which were Salmonella typhimurium and Salmonella enteritidis. A total of 53 resistance patterns were detected, and 10 strains were resistant to ampicillin-ampicillin/sulbactam-tetracycline-chloramphenicol-cefazolin-trimethoprim/sulfamethoxazole, which was the most common resistance pattern. Among the 60 cephalosporin resistant strains, 45 strains carried bla(TEM-1), 6 of which also carried bla(CTX-M-14) and 3 of which also carried bla(CTX-M-65). All the 32 strains carried only bla(TEM-1) show resistance to ampicillin and 31 of them show resistance to cefazolin. There were 2 strains showing negative results of gene detection. mcr-1 was detected in a multidrug resistant strain. Conclusion: The resistance of Salmonella.spp to ampicillin shows a serious situation in this region, and there were a number of multidrug resistant strains. The bla(TEM-1) was the major drug resistance gene detected in this research. Detection of the mcr-1 suggests the emergence of surveillance to colistin resistance of Salmonella.spp in this area.

[Retrospectively analysis of characteristics and risk factors of immune treatment-related hepatic adverse events in malignant tumor]

Objective: To explore the clinical features and risk factors of hepatic injury due to immune checkpoint inhibitors (CPI) therapy in malignant tumor. Methods: Data of 112 patients (64 men and 48 women) who received CPI between January 2016 and March 2019 in Chinese Academy of Medical Sciences and Peking Union Medical College Shenzhen Hospital, and Huazhong University of Science and Techology Union Shenzhen Hospital were retrospectively collected. The median age of these patients was 60 years. Results: Hepatic adverse events were observed in 30 patients out of 112 patients (26.8%). Among them, the incidence of grade 3-5 hepatic adverse events were 7.14% (8/112). The median time of hepatic adverse event occurrence was 3 weeks (2-30) after undergoing therapy. The results of univariate and multivariate analyses showed that liver cancer was attributed to the CPI induced hepatitis (P<0.05). Patients with severe hepatic injury got almost complete resolution after receiving methlprednisolone for 4 to 6 weeks. Conclusion: Live cancer is the risk factor of CPI-related hepatic adverse events.

Drug-resistance reversal in colorectal cancer cells by destruction of flotillins, the key lipid rafts proteins

Multi-drug resistance (MDR) of tumor cells attenuates the efficacy of anticancer drugs and has become the main reason for chemotherapy failure. It is indispensable to establish an effective way to reverse multi-drug resistance. Our previous work has shown that down-regulation of the ERK/MAPK signaling pathway activity can reverse the drug-resistance of resistant cells. Further-more, the effect of signal transduction is strongly associated with lipid rafts. The drug-resistance is reversed successfully after lipid rafts are destroyed by heptakis(2, 6-di-O-methyl)-β-cyclodextrin (MβCD). However, the reversal of the drug-resistance is not associated with down-regulation of the expression of ERK1/2. Cell membrane permeability may increase when lipid rafts are destroyed by MβCD, causing the reversal of drug-resistance due to an increase in accumulation of the drugs in the cytoplasm. To minimize the influence of MβCD on the cell membrane structure, we selected flotillin, a marker protein of lipid rafts, as the target molecule, to further investigate the mechanism of changes in drug resistance after destruction of the lipid rafts. The effect of flotillin on the reversal of the drug resistance was examined using an RNA interference (RNAi) in a retrovirus system in human drug-resistant strains of colorectal cancer cell line HCT-15. The results demonstrate that flotillin-1 downregulation by RNAi (Flot1-RNAi) reduced the drug resistance, caused cell cycle arrest and decreased the expression of ERK1/2; however, apoptosis was not significantly affected. Knockdown of flotillin-2 by RNAi (Flot2-RNAi) had effects similar to those of Flot1-RNAi except that the effects on expression of ERK1/2 and apoptosis were different. Screening of multiple pathways indicated that the PI3K/Akt signaling pathway was closely related. This experiment demonstrates the association between PI3K and drug resistance through the activation of PI3K and suggests that PI3K may play a key role during the development of resistance in CRC. The results reveal that the levels of IRS-1 and PI3K proteins in the Flot1-RNAi and Flot2-RNAi groups were significantly down-regulated. Knockdown of flotillins by RNAi reduced the resistance of HCT-15/ADM cells; the results investigations of the Akt pathway indicate a decrease in resistance after lipid raft destruction. These data confirm that knockdown of flotillin reduces the resistance of HCT-15/ADM cells, and the mechanism may be relevant to the PI3K/Akt pathway. Additionally, flotillin may be used as a potential target for chemotherapy in the treatment of colorectal cancer.

Risk factors for early-onset ventilator-associated pneumonia in aneurysmal subarachnoid hemorrhage patients

This study aimed to investigate the risk factors related to ventilator-acquired pneumonia (VAP) in aneurysmal subarachnoid hemorrhage (SAH) patients. From January 2011 to December 2015, a single-center retrospective study including 200 SAH patients requiring mechanical ventilation (MV) ≥48 h was performed. The clinical data of these patients were collected and analyzed. The age range of the patients were 41-63 and 72 (36%) were male. The Glasgow coma scale score range was 5-15 and the Simplified Acute Physiology Score II range was 31-52. One hundred and forty-eight (74%) patients had a World Federation of Neurosurgeons (WNFS) score ≥III. Aneurysm was secured with an endovascular coiling procedure in 168 (84%) patients and 94 (47%) patients presented VAP. Male gender (OR=2.25, 95%CI=1.15-4.45), use of mannitol (OR=3.02, 95%CI=1.53-5.94) and enteral feeding above 20 kcal·kg-1·day-1 (OR=2.90, 95%CI=1.26-6.67) after day 7 were independent factors for VAP. Patients with early-onset VAP had a longer duration of sedation (P=0.03), MV (P=0.001) and ICU length of stay (P=0.003) and a worse Glasgow Outcome Scale score (P<0.001), but did not have a higher death rate.

[Curative effects and influenced factors of primary chemotherapy with single-agent methotrexate on low-risk gestational trophoblastic neoplasia]

Objective: To evaluate the efficacy of primary chemotherapy with single-agent methotrexate (MTX) for low-risk gestational trophoblastic neoplasia and to analysis the influenced factors. Methods: We retrospectively reviewed 259 cases with low-risk gestational trophoblastic neoplasia whose primary chemotherapies were MTX 0.4 mg·kg(-1) (maximum 25 mg) daily for 5 days every other week. Patients' data between January 2001 and June 2015 was collected and the relationships of different factors to outcomes of chemotherapy were also evaluated. Results: 183 of the 259 patients (70.66%, 183/259) achieved complete primary remission and all patients achieved complete remission after salvage chemotherapy. Univariate analysis showed that FIGO score, serum level of HCG before treatment and interval months from previous pregnancy were significantly associated with outcome of chemotherapy (P=0.001, 0.018, 0.014 respectively). Logistic regression analysis showed that the FIGO score (OR=4.094) and antecedent pregnancy (OR=0.268) were two independent factors predictive for the outcome of chemotherapy. Conclusions: Primary chemotherapy with single-agent MTX may still be one of the options for patients with low risk GTN. The FIGO score and antecedent pregnancy are two independent risk factors of outcome of single-agent MTX chemotherapy.

Relationship between serum irisin levels and urinary albumin excretion in patients with type 2 diabetes

AIM

Irisin is first discovered as a potential mediator of obesity related energy homeostasis. Recent studies indicate that irisin is associated with endothelial dysfunction and atherosclerosis in patients with type 2 diabetes. Our objective was to examine the relationship between irisin and urinary albumin excretion in patients with type 2 diabetes.

METHODS

100 newly diagnosed patients with type 2 diabetes and 100 healthy subjects were selected. Serum irisin levels were measured by ELISA, and urine albumin was measured by radioimmunoassay. High resolution ultrasound was used to measure brachial artery diameter at rest, after reactive hyperemia (flow-mediated arterial dilation, FMD) and after sublingual glyceryltrinitrate.

RESULTS

Patients with type 2 diabetes presented decreased irisin levels when compared to controls (14.12±3.93 versus 28.98±2.56ng/ml, P=0.015).Serum irisin levels in the microalbuminuric and macroalbuminuria subgroup were 9.89±1.56ng/ml and 5.67±1.89ng/ml, respectively, which were significantly lower than those in the normoalbuminuria (15.97±3.12ng/ml). In comparison to microalbuminuric subgroup, macroalbuminuria subgroup had lower levels of irisin. By dividing the distribution of serum irisin levels into quartiles, FMD was increased gradually with the increase of serum irisin levels (P<0.001). Multiple stepwise linear regression analysis showed that FMD (β=0.75, P=0.002), 2-hBG (β=-0.25, P=0.038) and UAE (β=-0.87, P=0.008) were significantly associated with irisin. Pearson's correlation analyses showed a negative correlation between irisin and logUAE (r=-0.57) and between FMD and logUAE (r=-0.47), and positive correlations between irisin and FMD (r=0.51).

CONCLUSIONS

Decreased plasma levels of irisin seem to be associated with UAE and FMD in patients with type 2 diabetes.

Aspirin may modify tumor microenvironment via antiplatelet effect

High-quality evidence suggests that aspirin is a promising agent for cancer prevention and treatment. Direct inhibition of cyclooxygenase-2 (COX-2) pathway is generally thought to be the main mechanism by which aspirin inhibits cancer development. However, either pharmacological properties of aspirin or recent results of epidemiologic studies do not support that mechanism. To address this inconsistency, we hypothesize that antiplatelet effect of aspirin via inhibition of COX-1 may be one of potential mechanisms to inhibit carcinogenesis. Aberrant platelet activation will lead to promote hostility of tumor microenvironment by releasing an abundant array of angiogenesis regulators. Given the outstanding ability of antiplatelet, aspirin may restore balance of pro- and anti-angiogenic factors released from platelet to "normalize" tumor vasculature and shape tumor microenvironment to some extent, which will not only diminish tumor aggressiveness and progression, but also enhance the sensitivity to therapeutic treatment. Thus, targeting the platelet activation leading to alter tumor microenvironment may provide a novel way to tumor therapy.

Effect of asymmetric dimethylarginine on osteoblastic differentiation

BACKGROUND

Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide synthase (NOS) that accumulates in renal insufficiency and may be a uremic toxin. To determine whether ADMA inhibits bone metabolism, we investigated the in vitro effect of ADMA on osteoblastic differentiation in mouse bone marrow-derived mesenchymal stem cells (BMSCs).

METHODS

The effect of ADMA on nitric oxide (NO) production was determined by measuring the stable end product of NO, nitrite, in the culture medium using commercial NO kit. The temporal sequence of osteoblastic differentiation in BMSCs was assessed in the presence and absence of ADMA by measuring alkaline phosphatase (ALP) activity, mineralization, and osteoblast gene expression at 0, 4, 8, 12 days of culture.

RESULTS

ADMA (5, 50, 500 micromol. L-1) resulted in a dose-dependent decrease in nitrite formation in conditioned media of BMCS cultures, consistent with inhibition of NOS. ADMA treatment was associated with reduced ALP activity, calcium deposition and osteoblast-related gene expression in BMSCs cultures. Concurrent treatment with l-arginine (3600 micromol. L-1) reversed the ADMA (500 micromol. L-1)-mediated decrease in NO production, restored the differentiation potential of BMSCs, and significantly attenuated the down-regulation of Cbfa1 and osteocalcin gene expression by ADMA.

CONCLUSIONS

ADMA inhibition of the NO-NOS pathway in BMSCs impairs osteoblastic differentiation of mouse BMSC cultures. These studies further support a role of NO in the local regulation of bone metabolism and the possibility that ADMA may act as uremic toxin on bone through its effect to inhibit NO actions in osteoblasts.

Opposing effect of p38 CCDPK and p44/42 CCDPK signaling on TNF-alpha-induced apoptosis in bovine aortic endothelial cells

AIM

To investigate the pro-apoptotic role of tumor necrosis factor alpha (TNF-alpha) in cultured bovine aortic endothelial cells (BAEC) and its underlied apoptotic signaling pathways.

METHODS

BAEC were cultured and passaged in Dulbecco's modified Eagle's medium (DMEM). Morphologic changes and quantification of apoptotic cells were determined under fluorescence microscope after TNF-alpha treated BAEC for 24 h with Hoechst 33258 staining. Cell viability was determined with MTT method. DNA fragmentation was visualized by agarose gel electrophoresis. The expression of phospho-p38 and phospho-p44/42 Ca2+-calmodulin dependent protein kinase (CCDPK, formerly called MAPK) was measured by Western blotting.

RESULTS

TNF-alpha elicited typical apoptotic morphologic changes (chromatic condensation, nucleus fragmentation) and DNA fragmentation. At 1000-5000 kU/L, incubation with TNF-alpha for 24 h induced BAEC apoptosis and both of phospho-p38 and phospho-p44/42 CCDPK expression in a concentration-dependent manner. Interestingly, TNF-alpha-stimulated activation of p44/42 CCDPK was completely blocked, TNF-alpha-induced apoptosis was markedly increased by preincubation with U0126, a specific p44/42 CCDPK inhibitor. However, SB203580, a specific p38 CCDPK inhibitor, completely blocked TNF-alpha-stimulated activation of p38 CCDPK, and enhanced the expression of phospho-p44/42 CCDPK induced by TNF-alpha, substantially inhibited the pro-apoptotic effect of TNF-alpha.

CONCLUSION

TNF-alpha simultaneously activates p38 CCDPK and p44/42 CCDPK, and these two CCDPK signaling pathways appeared to play opposing roles in TNF-alpha-induced apoptosis in BAEC.

Dengue in China: a clinical review

Three etiologically proven outbreaks of dengue fever and one etiologically confirmed epidemic of dengue haemorrhagic fever have occurred in south China since 1978. The first of these, an epidemic of dengue due to virus type 4 took place in Shiwan town, Foshan city, Guangdong Province, in 1978; the epidemic began in May and ended in November. The clinical manifestations of 583 hospitalized patients were observed from August to October. The majority (81.3%) of patients were aged 21-50 years (male:female = 1.2:1). The course of illness was about 1 week in most cases; three patients (0.5%) died. A local outbreak of dengue due to virus type 1 occurred in Shiqi town, Zhongshan County, Guangdong Province, from September to November 1979. The majority of patients were older children and adolescents. There was no marked difference between males and females in terms of the course of the illness, and there were no complications or deaths. A large epidemic of dengue due to virus type 3 occurred on Hainan Island in 1980. The clinical manifestations of 510 hospitalized patients (mostly adolescents and adults) were observed from April to September. Some patients developed rare complications, such as loss of hair, acute intravascular haemolysis, and multiple peripheral paralysis; there were four deaths (0.78%). The first known epidemic of dengue haemorrhagic fever in China occurred among 10-29-year-olds on Hainan Island in 1985 and 1986. There were no essential differences between males and females. Some cases had rare complications such as acute intravascular haemolysis, while others had diffuse intravascular coagulation and altered mental status; 10 patients (6.5%) died.

A survey of epidemiology of Gnathostoma hispidum and experimental studies of its larvae in animals

The present study is concerned with a survey of the epidemiology and infectivity of Gnathostoma hispidum larvae in animals. A total or 3,478 pigs were examined in Hongze-Lake, Jiangsu; Po-Lake, Anhui; and Jiujiang, in Jiangxi Province. The infection rate of G. hispidum in pigs was 14.9%. The prevalence in pigs in the lake districts (26.4%) was considerably higher than in the mountainous districts (5.1%). The results of field surveys and experimental studies revealed that in China, 38 animal species served as the first and the second intermediate hosts and paratenic hosts of G. hispidum. Among them, 23 species (6 cyclops, 13 fish, 2 frogs and one each of snake and bird) were similar to the hosts of G. spinigerum. Carnivorous fish, frogs and rodents are an important infection source for gnathostomiasis. Experiments demonstrated that Macaca mulatta was successfully infected with the early 3rd-stage larvae from cyclops or the advanced 3rd-stage larvae from fish. The domestic cat and white rat were experimentally infected by skin penetration by advanced 3rd-stage larvae of G. hispidum obtained from fish; the results of the test were all positive. The survey of epidemiology and biology of G. hispidum and G. spinigerum were quite similar, so the authors consider that humans may be infected by G. hispidum.

The first epidemic of dengue hemorrhagic fever in the People's Republic of China

The first epidemic of dengue in China associated with significant severe and fatal hemorrhagic disease which met the World Health Organization case definition occurred on Hainan Island in 1985-1986. The epidemic began in Zhan County in September 1985, spread throughout the coastal areas, and ultimately involved 13 counties and cities of the island in 1986. The mosquito vector was Aedes aegypti. The morbidity associated with dengue infection on Hainan Island was 1,913 per 100,000 residents, with a case fatality rate of 0.25%. Severe disease was more prevalent in the 10-29-year-old age group. Principal clinical features in laboratory-confirmed cases were fever, osteoarthralgia, hemorrhage and/or shock, and thrombocytopenia. Complications such as acute intravascular hemolysis, diffuse intravascular coagulation, hemoconcentration, pleural effusion, altered mentality, and pneumonia were also observed. One hundred twenty-five isolates of dengue 2 virus were recovered from acute-phase serum samples from 278 patients, and 5 strains of this same virus serotype were isolated from 5 pools of adult Ae. aegypti.