Comparison of Safety of Different Vaccine Boosters Following Two-Dose Inactivated Vaccines: A Parallel Controlled Prospective Study.

A vaccine booster to maintain high antibody levels and provide effective protection against COVID-19 has been recommended. However, little is known about the safety of a booster for different vaccines. We conducted a parallel controlled prospective study to compare the safety of a booster usingfour common vaccines in China. In total, 320 eligible participants who had received two doses of an inactivated vaccine were equally allocated to receive a booster of the same vaccine (Group A), a different inactivated vaccine (Group B), an adenovirus type-5 vectored vaccine (Group C), or a protein subunit vaccine (Group D). A higher risk of adverse reactions, observed up to 28 days after injection, was found in Groups C and D, compared to Group A, with odds ratios (OR) of 11.63 (95% confidence interval (CI): 4.22-32.05) and 4.38 (1.53-12.56), respectively. Recipients in Group C were more likely to report ≥two reactions (OR = 29.18, 95% CI: 3.70-229.82), and had a higher risk of injection site pain, dizziness, and fatigue. A gender and age disparity in the risk of adverse reactions was identified. Despite the majority of reactions being mild, heterologous booster strategies do increase the risk of adverse reactions, relative to homologous boosters, in subjects who have had two doses of inactive vaccine.

Acute mushroom poisoning of Amanita pseudosychnopyramis: A case report from Fujian, China with exact species identification and descriptive study.

Mushroom poisoning is a deeply concerning food safety problem that affects the public in China every year. Although there are statistics on the number of poisonings and incidents, there is a lack of data on the types of toxic mushrooms, clinical manifestations and toxins. A case of wild mushroom poisoning occurred in Xiamen. Descriptive epidemiological investigation, toxins detection, and morphological and phylogenetic identification were immediately performed. The patients exhibited typical neurotoxic symptoms after consuming wild mushrooms, including chills, vertigo, drowsiness, salivation and coma. The average incubation period was 30 min. Treatments that were adopted included fluid infusion, gastric lavage, catharsis, and liver protection treatment. All patients recovered within 10 days. The species was identified as Amanita pseudosychnopyramis, and its contents of muscarine, muscimol and ibotenic acid were 170.3 ± 5.9 mg/kg, 835.4 ± 43.1 mg/kg and 637.9 ± 54.8 mg/kg in dry weight, respectively, as detected by ultrahigh-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). To our knowledge, this is the first report of Amanita pseudosychnopyramis poisoning worldwide.

Global Genomic Characterization of Salmonella enterica Serovar Telelkebir.

Non-typhoidal Salmonella (NTS) is a common cause for self-limiting gastroenteritis, representing a public health concern globally. NTS is one of the leading causes of foodborne illnesses in China; however, the invasive infection caused by NTS is largely underappreciated. Here, we reported an NTS invasive infection caused by an infrequently reported serovar Telelkebir (13,23:d:e,n,z15) strain FJ001 in China, which carries antimicrobial-resistant genes [fosA7 and aac(6')-Iaa] and typhoid-toxin genes (cdtB, pltA, and pltB). By conducting the whole genomic sequencing, we also investigated the relatedness of this strain with an additional 120 global contextual Salmonella enterica serovar Telelkebir (S. Telelkebir) isolates, and assessed the antimicrobial-resistant determinants and key virulence factors using the available genomic dataset. Notably, all 121 (100%) of the S. Telelkebir strains possessed the typhoid toxin genes cdtB, pltA, and pltB, and 58.67% (71/121) of S. Telelkebir harbored antimicrobial-resistant gene fosaA7. The study by core genome multilocus sequence typing (cgMLST) and core single-nucleotide polymorphism (SNP)-based phylogenomic analysis demonstrated that the S. Telelkebir isolates from different sources and locations clustered together. This suggests that regular international travels might increase the likelihood of rapid and extensive transmissions of potentially pathogenic bacteria. For the first time, our study revealed the antimicrobial resistance, virulence patterns, and genetic diversity of the serovar S. Telelkebir isolate in humans and similar isolates over the world. The present study also suggests that genomic investigation can facilitate surveillance and could offer added knowledge of a previously unknown threat with the unique combination of virulent and antimicrobial-resistant determinants.

Frequent Import and Multiple Sources of Dengue Fever have Changed the Epidemic Situation of the Disease in Fujian Province, China.

OBJECTIVE: The aim of this study was to update the epidemic situation of dengue fever (DF) and provide new insights for the consideration of disease control in Fujian province, China. METHODS: Details about DF cases in Fujian reported during 2004-2017 were collected and analyzed. The envelope (E) genes of isolates of dengue virus (DENV) were sequenced for phylogenetic analysis. RESULTS: The number of imported DF cases had increased dramatically since 2013, and the source regions expanded from Southeast Asia to South Asia, America, Oceania, and Africa, as well as the surrounding provinces. This resulted in local outbreaks and indigenous cases of DF that occurred more frequently, with 10 of 13 local outbreaks and 85.9% (1,252/1,458) of indigenous cases reported in 2013-2017. Compared with only two coastal cities before 2013, four coastal and one inland city in 2013-2017 experienced the local DF outbreaks. The phylogenetic analysis of E genes confirmed that the import of DENV, not only from abroad but also from the surrounding provinces, played an important role in dissemination and local outbreaks of DF in Fujian. CONCLUSIONS: The frequent import of DF cases from not only abroad but also the surrounding provinces resulted in increased incidence, frequent local outbreaks, and expansion of distribution in Fujian in recent years. There is a need for urgent measures to improve disease control in this province.

RT-nPCR Assays for Amplification and Sequencing of VP1 Genes in Human Enterovirus A-D from Clinical Specimens.

OBJECTIVE: To develop RT-nPCR assays for amplifying partial and complete VP1 genes of human enteroviruses (HEVs) from clinical samples and to contribute to etiological surveillance of HEV-related diseases. METHODS: A panel of RT-nPCR assays, consisting of published combined primer pairs for VP1 genes of HEV A-C and in-house designed primers for HEV-D, was established in this study. The sensitivity of each RT-nPCR assay was evaluated with serially diluted virus stocks of five serotypes expressed as CCID 50 per µL and copies per µL, and the newly established methods were tested in clinical specimens collected in recent years. RESULTS: The sensitivity of RT-nPCR assays for amplifying partial VP1 gene of HEVs was 0.1 CCID 50 per µL and 10 virus copies per µL, and for the complete VP1 gene was 1 CCID 50 per µL and 100 virus copies per µL, using serially-diluted virus stocks of five serotypes. As a proof-of-concept, 25 serotypes were identified and complete VP1 sequences of 23 serotypes were obtained by this system among 858 clinical specimens positive for HEVs during the past eight surveillance seasons. CONCLUSION: This RT-nPCR system is capable of amplifying the partial and complete VP1 gene of HEV A-D, providing rapid, sensitive, and reliable options for molecular typing and molecular epidemiology of HEVs in clinical specimens.

A study of the relationship between human infection with avian influenza a (H5N6) and environmental avian influenza viruses in Fujian, China.

BACKGROUND: Avian influenza A (H5N6) virus poses a great threat to the human health since it is capable to cross the species barrier and infect humans. Although human infections are believed to largely originate from poultry contaminations, the transmissibility is unclear and only limited information was available on poultry environment contaminations, especially in Fujian Province. METHODS: A total of 4901 environmental samples were collected and tested for Avian Influenza Virus (AIV) from six cities in Fujian Province through the Fujian Influenza Surveillance System from 2013 to 2017. Two patient-related samples were taken from Fujian's first confirmed H5N6 human case and his backyard chicken feces in 2017. Chi-square test or Fisher's exact probability test was used to compare the AIV and the viral subtype positive rates among samples from different Surveillance cities, surveillance sites, sample types, and seasons. Phylogenetic tree analysis and molecular analysis were conducted to track the viral transmission route of the human infection and to map out the evolutions of H5N6 in Fujian. RESULTS: The overall positive rate of the H5 subtype AIVs was 4.24% (208/4903). There were distinctive differences (p < 0.05) in the positive rates in samples from different cities, sample sites, sample types and seasons. The viruses from the patient and his backyard chicken feces shared high homologies (99.9-100%) in all the eight gene segments. Phylogenetic trees also showed that these two H5N6 viruses were closely related to each other, and were classified into the same genetic clade 2.3.4.4 with another six H5N6 isolates from the environmental samples. The patient's H5N6 virus carried genes from H6N6, H5N8 and H5N6 viruses originated from different areas. The R294K or N294S substitution was not detected in the neuraminidase (NA). The S31 N substitution in the matrix2 (M2) gene was detected but only in one strain from the environmental samples. CONCLUSIONS: The H5 subtype of AIVs has started circulating in the poultry environments in Fujian Province. The patient's viral strain originated from the chicken feces in his backyard. Genetic reassortment in H5N6 viruses in Fujian Province was indicated. The H5N6 viruses currently circulating in Fujian Province were still commonly sensitive to Oseltamivir and Zanamivir, but the resistance against Amantadine has emerged.

The role of lipid rafts in the early stage of Enterovirus 71 infection.

BACKGROUND/AIMS: Although it has been widely accepted that Enterovirus 71 (EV71) enters permissive cells via receptor-mediated endocytosis, the details of entry mechanism for EV71 still need more exploration. This study aimed to investigate the role of lipid rafts in the early stage of EV71 Infection. METHODS: The effect of cholesterol depletion or addition of exogenous cholesterol was detected by immunofluorescence assays and quantitative real-time PCR. Effects of cholesterol depletion on the association of EV71 with lipid rafts were determined by flow cytometry and co-immunoprecipitation assays. Localization and internalization of EV71 and its receptor were assayed by confocal microscpoy and sucrose gradient analysis. The impact of cholesterol on the activation of phosphoinositide 3'-kinase/Akt signaling pathway during initial virus infection was analyzed by Western-blotting. RESULTS: Disruption of membrane cholesterol by a pharmacological agent resulted in a significant reduction in the infectivity of EV71. The inhibitory effect could be reversed by the addition of exogenous cholesterol. Cholesterol depletion post-infection did not affect EV71 infection. While virus bound equally to cholesterol-depleted cells, EV71 particles failed to be internalized by cholesterol-depleted cells. EV71 capsid protein co-localized with cholera toxin B, a lipid-raft-dependent internalization marker. CONCLUSION: Lipid rafts play a critical role in virus endocytosis and in the activation of PI3K/Akt signaling pathway in the early stage of EV71 infection.

Differences in the levels of gastric cancer risk factors between Nanjing and Minqing counties, China.

OBJECTIVES: In Fujian Province, China, gastric cancer is one of the leading causes of mortality among all malignant tumors. Nanjing county and Minqing county are located in inland Fujian and have similar general demographics. However, the adjusted mortality rate of gastric cancer in Minqing was found to be much higher than that in Nanjing. We sought to explore factors associated with this increased risk of gastric cancer between the two counties. METHODS: We recruited 231 and 224 residents from Nanjing and Minqing, respectively, and analyzed differences between their dietary habits, Helicobacter pylori infection rates, and concentrations of serum pepsinogen I, pepsinogen II, gastrin-17, and ratio of pepsinogen I:II. RESULTS: Subjects in Minqing had more first-degree relatives who had been diagnosed with upper gastrointestinal tumor, more unhealthy dietary habits, a higher Helicobacter pylori positive rate, and greater proportion of abnormal serum gastrin-17 than those in Nanjing did. CONCLUSIONS: The factors that differed between these two counties might indicate that residents in Minqing have a higher risk for developing gastric cancer than those in Nanjing do.

[Characteristics of complete genome of pandemic A/H1N1/2009 influenza virus isolated in Fujian Province, China].

This study aims to investigate the characteristics of genomic variation of pandemic A/H1N1/2009 influenza virus isolated in Fujian Province, China. Complete genome sequence analysis was performed on 14 strains of pandemic A/H1N1/2009 influenza virus isolated from Fujian during 2009-2012. All virus strains were typical low-pathogenic influenza viruses, with resistance to amantadine and sensitivity to neuraminidase inhibitors. Eight genome fragments of all strains were closely related to those of A/California/07/2009 (H1N1) vaccine strain, with > or = 98.2% homology. Compared with the vaccine strain, the influenza strains from Fujian had relatively large variation, and variation was identified at 11 amino acid sites of the HA gene of A/Fujiangulou/SWL1155/2012 strain, including 4 sites (H138R, L161I, S185T, and S203T) involved inthree antigen determinants (Ca, Sa, and Sb). In conclusion, the influenza vaccine has a satisfactory protective effect on Fujian population, but the influenza strains from Fujian in 2012 has antigenic drift compared with the vaccine strain, more attention should therefore be paid to the surveillance of mutations of pandemic A/H1N1/2009 influenza virus.

IL-4 and IL-5 secretions predominate in the airways of wistar rats exposed to toluene diisocyanate vapor.

OBJECTIVES: We established a Wistar rat model of asthma caused by toluene diisocyanate (TDI) exposure, and investigated the relationship between TDI exposure concentrations and respiratory hypersensitivity, airway inflammation, and cytokine secretions in animals, to better understand the mechanism of TDI induced occupational asthma. METHODS: Wistar rats were exposed to two different concentrations of TDI vapor four hours a day for five consecutive days. Bronchoalveolar lavage (BAL) was performed, and differential leucocytes from the BAL fluid were analyzed. Lung histopathological examination was carried out to investigate the inflammatory status in the airways. Production of cytokines interleukin (IL)-4 and IL-5 productions in the BAL fluid in vivo was determined with enzyme-linked immunosorbent assay kits. RESULTS: The TDI-exposed rats exhibited greater airway hypersensitivity symptoms than the control rats. The BAL differential cell count and lung histopathological examination demonstrated that inflammation reactions were present in both the central and peripheral airways, characterized with marked infiltration of eosinophils in the TDI-exposed rats. The cytokine assay showed that IL-4 and IL-5 were predominantly produced in the BAL fluid in vivo. CONCLUSIONS: These findings imply that TDI exposure concentrations may greatly affect the occurrence and extent of inflammatory events and that Th2 type cytokines may play an important role in the immunopathogenesis of TDI-induced occupational respiratory hypersensitivity.

[Molecular epidemiology of HFMD-associated pathogen coxsackievirus A6 in Fujian Province, 2011-2013].

In order to characterize the molecular epidemiology of HFMD-associated Coxsackievirus A6 (CVA6) in Fujian Province, a total of 1340 specimens from non-EV71 non-CVA16 HFMD patients were collected during 2011-2013. Isolated virus strains were identified and subtyped. Full-length coding regions for the VP1 gene of the predominant serotype CVA6 isolates were amplified and sequenced. Among the 375 non-EV71 non-CVA16 HFMD cases confirmed by virus isolation and molecular subtyping, 182 (48.5%) were found to be caused by CVA6, accounting for 7.9%, 16.2% and 39.6% HFMD-associated enteroviruses in FujianProvince during 2011, 2012, and 2013, respectively. Compared with general features observed in the HFMD epidemic, no difference in CVA6-specificity or severity rates was observed between geographical origins, gender, or age groups. Nucleotide sequence analyses of VP1 genes revealed high diversity levels of 16.2%-18.6% among CVA6 strains from Fujian Province, in contrast to the prototype CVA6 strain, and showed low levels of diversity in the amino acid sequences (4.3%-6.2%). Phylogenetic analysis also indicated that CVA6 isolates from Fujian Province were distinct from the prototype strain and other isolates from abroad; however, it was homologous to domestic strains, although the Fujian isolates clustered into multiple branches. These results suggested that significant changes in the pathogenic spectrum of HFMD in Fujian Province occurred during 2011-2013, as CVA6 was one of the predominant serotypes of HFMD. CVA6 isolates from Fujian Province were co-circulating and co-evolving with other domestic strains as multiple closely related CVA6 transmission chains were observed in Fujian Province overall and within each prefecture.

[Immuno-affinity chromatographic purification: the study of methods to test citrinin in monascus products by high performance liquid chromatography].

OBJECTIVE: To establish a method to test citrinin (CIT) in monascus products by immuno-affinity chromatography (IAC)-high performance liquid chromatography (HPLC), and to detect the content of CIT in monascus products in Fujian province. METHODS: IAC-HPLC was applied to detect the CIT content in monascus products. The conditions to use HPLC were as follows: C(18) reversed-phase chromatographic column, 150.0 mm×4.6mm×3 µm; mobile phase: the volume ratio of acetonitrile and 0.1% phosphoric acid solution at 65:35; isocratic elution; column temperature: 28°C; flow velocity: 0.8 ml/min; fluorescence detector, excitation wavelength (λ(ex)) was 331 nm and emission wavelength (λ(em)) was 500 nm. The standard curved was established by the linear regression of peak area (Y) to CIT content (X, ng/ml). The accuracy and precision of the method would then be verified. And 32 kinds of monascus products were determined and their color values were compared by this method. RESULT: The standard curve established in this study was Y = 4634.8X-136.42, r = 1.000; whose limits of detection was 20 µg/kg and the limits of qualification was 64 µg/kg. In the range between 200 and 800 µg/kg, the standard recovery rate was 98.9% - 110.0% (n = 3), and the relative standard deviation (RSD) was 0.51% - 1.76%. Out of the 32 samples, CIT was detected from 11 samples of monascus rice, 9 samples of monascus powder and 5 samples of monascus pigments, the content was around 0.212 - 14.500 mg/kg. 4 out of 7 functional monascus samples were detected out CIT, whose content at 0.142 - 0.275 mg/kg. CONCLUSION: The method to detect CIT in monascus products by IAC-HPLC has been established.

Serum pepsinogens, gastrin-17 and Helicobacter pylori antibody in the residents of two cities in china with distinct mortality rates of gastric cancer.

Gastric cancer is one of the most common malignant tumors causing death in Fujian Province, China. However, the mortality of gastric cancer is greatly varied in different areas in Fujian; for example, the mortality in Changle City is 7.4 times higher than that in Fuan City. In this study, we compared the differences in serological parameters, pepsinogen (PG) I, PG II, gastrin-17 (G-17), and Helicobacter pylori (H. pylori) antibody, between the two cities. It has been reported that low serum PG I is correlated with atrophic gastritis, a high-risk condition for developing gastric cancer, while high serum G-17 has been used for serological detection of atrophic corpus gastritis. We recruited 224 healthy subjects in Changle and 229 healthy subjects in Fuan, matched in age and sex. The serum levels of PG II and G-17 were significantly higher in Changle than those in Fuan. Importantly, the frequency of the subjects with low serum PG I (< 25 µg/L) was significantly higher in Changle than in Fuan, although the serum PG I levels were similar between the two cities. Moreover, the percentage of the subjects with high serum G-17 (≥ 2 pmol/L) and the positive rate of serum IgG antibody against H. pylori were significantly higher in Changle than those in Fuan. The detected differences in these serological parameters are consistent with the notion that the prevalence of atrophic gastritis may be higher in Changle than in Fuan, which results in a higher risk condition for developing gastric cancer in Changle.

Modulations of immune functions and oxidative status induced by noise stress.

Noise has long been realized as an environmental stress causing physiological, psychological and behavioral changes in humans. The aim of the present study was to determine the effect of acute or chronic noise stress on both cellular and humoral immune responses and oxidative status. BALB/c mice were exposed to 90 dB (A) white noise 5 h per day for either 3 d or 4 wk. Hormone levels, splenic lymphocyte proliferation, lymphocyte subsets in spleen and thymus, serum antibody and oxidative status were determined. A 3-d exposure to noise stress resulted in increased hormone levels, splenic lymphoproliferation and serum IgM. On the other hand, a 4-wk exposure to noise stress caused a reduction of splenic lymphoproliferation, splenic CD4(+) cells and serum IgG, but hormone levels and urinary 8-hydroxy-2'deoxyguanosine (8-OHdG) were increased. These results imply that acute exposure to noise stress may enhance immune responses, whereas chronic exposure to noise stress may suppress both cellular and humoral immune functions. The effect of noise stress on immune functions may be related to neuroendocrine modulation and oxidative imbalance as well.

Potassium excretion in healthy Japanese women was increased by a dietary intervention utilizing home-parcel delivery of Okinawan vegetables.

Potassium, which is abundant in vegetables, is inversely related to blood pressure. Although the situation has changed somewhat in recent years, the Okinawan diet has generally included a large amount of vegetables, and until recently Okinawans had the lowest rates of mortality due to stroke and coronary heart disease in Japan. Based on the hypothesis that these low mortality rates are partly attributable to increased potassium intake resulting from the high vegetable consumption, this study examined whether increasing the consumption of typical yellow-green Okinawan vegetables increases potassium intake. The purpose of this investigation was to determine whether increased consumption of these vegetables should be one of the dietary modifications recommended in public health promotion programs for Okinawans. The study employed 56 healthy, normotensive, free-living Japanese women aged 18-38 years living in Okinawa. They were randomized to a dietary intervention group (n=27) or a control group (n=29). Members of the dietary intervention group received an average weight of 371.4 g/day of a combination of the following vegetables twice weekly through an express home parcel deliver service for a period of 14 days: Goya (Momordica charantia), green papaya (Carica papaya), Handama (Gynura bicolor), Karashina (Brassica juncea), Njana (Crepidiastrum lanceolatium), Fuchiba (Artemisia vulgaris) and Fudanso (Beta vulgaris); and they consumed an average of 144.9 g/day, resulting in a 20.5% increase in their urinary potassium excretion over the baseline (p=0.045). The members of the control group were asked to avoid these vegetables, and the change in potassium excretion in this group was not significant (p=0.595). Urinary sodium and magnesium excretions, systolic and diastolic blood pressures, folic acid, triglycerides and serum high density lipoprotein cholesterol, low density lipoprotein cholesterol and total cholesterols changed non-significantly in both groups. Also, post-intervention urinary potassium excretion correlated positively with vegetable consumption in both the dietary intervention (p<0.0001) and control (p=0.008) groups and with Okinawan vegetable intake in the dietary intervention group (p=0.0004).

Associations between lifestyle and mental health in a group of Japanese overseas workers and their spouses resident in Düsseldorf, Germany.

This study investigated associations between lifestyle factors and selected aspects of mental health in a group of Japanese overseas workers and their accompanying spouses who were residing in and around Düsseldorf, Germany, in February 1994. Considering four aspects of mental health (depression, mental instability, nervousness and neurosis) and six lifestyle factors (alcohol consumption, sleeping hours, cigarette smoking, physical exercise, eating breakfast and eating snacks), a cross-sectional study involving 822 volunteers (486 workers and 336 spouses) was performed using the Todai Health Index (THI) for surveying self-perceived health and a lifestyle related self-administered questionnaire. Alcohol consumption had no associations with any of the four aspects of mental health, and only very weak inverse associations were found between the other five lifestyle factors and the four aspects of mental health in the workers group. In the spouses group, physical exercise was the only lifestyle factor significantly associated with mental health.

Airway inflammatory and immunological events in a rat model exposed to toluene diisocyanate.

To investigate the inflammatory and immunological events in the airway induced by a short period of repeated exposure to toluene diisocyanate (TDI), an animal model was established, which resembled the industrial field exposure. After whole body exposure of Wistar rats to 0.38 and 1.20 ppm TDI vapor 4h a day for five consecutive days in a glass chamber, bronchoalveolar lavage (BAL) was performed. BAL fluid cellular and cytokine contents were then determined. Histopathological examinations were also carried out on the lungs. The TDI vapor exposure resulted in airway symptoms similar to those in occupational asthma. BAL fluid cellular analysis and lung histopathological examination revealed that inflammatory response was characterized by marked eosinophil infiltration of the airways. The cytokine assay revealed significant production of IL-4 in the airways of the TDI exposed rats as compared to the control rats. These findings indicated that a short period of repeated exposure to TDI vapor may cause respiratory hypersensitivity in which airway inflammatory and immunological events represented by eosinophil infiltration and Th2 cytokines may play an important role. Also, this animal model may be suitable for exploring the mechanism underlying TDI-induced occupational asthma.

Detection of p53 and K-ras mutations in sputum of individuals exposed to smoky coal emissions in Xuan Wei County, China.

Lung cancer mortality rates in the Xuan Wei County population are among the highest in China and are associated with exposure to indoor emissions from the burning of smoky coal. Previous studies of lung tumors from both non-smoking women and smoking men in this region showed high frequencies of mutations, consisting mostly of G-->T transversions in the p53 tumor suppressor gene and K-ras oncogene, suggesting that these mutations were caused primarily by polycyclic aromatic hydrocarbons. In this study sputum samples from 92 individuals with no evidence of lung cancer from Xuan Wei County were screened for p53 and K-ras mutations. Sputum cells were collected on glass slides by sputum cytocentrifugation, stained and cytopathologically analyzed. Cytologically non-malignant epithelial cells were taken from each sputum sample using a laser capture microdissection microscope and molecularly analyzed. Cells taken from the sputum of 15 (16.3%) individuals were mutation positive, including 13 (14.1%) individuals each with a p53 mutation, 1 (1.1%) individual with a K-ras mutation and 1 (1.1%) individual with a p53 and a K-ras mutation. p53 mutations were found in both the sputum of individuals with evidence of chronic bronchitis (3 of 46 or 6.5%) and those without evidence of this disease (11 of 46 or 23.9%). Therefore, mutations in the p53 gene and, to a lesser extent, the K-ras gene were frequent in non-malignant epithelial cells taken from the sputum of individuals without evidence of lung cancer who were exposed to smoky coal emissions in Xuan Wei County and were at a high risk for developing the disease.