To provide a scientific basis for determining the health surveillance period of dust-exposed workers, data of a retrospective cohort study was re-analyzed with emphasis on natural course of silicosis. 33640 workers exposed to silica dust who were employed for at least 1 year from 1972 to 1974 in twenty Chinese mines or pottery factories were included as subjects, and were followed up till December 31, 1994. The cohort included subjects from 8 tungsten mines, 4 tin mines and 8 pottery factories. Our results showed that the mean latency of silicosis, for all the cases of the cohorts, was 22.9 +/- 9.8 y. 52.2 % of silicosis was diagnosed approximately 9.1 +/- 5.7 y after the dust exposure had ceased. The progression rates of silicosis from stage I to II and from stage II to III were 48.2 % and 18.5 %, and the duration was 4.1 +/- 0.2 and 6.8 +/- 0.2 y, respectively. The survival times of silicosis stage I , II and III, from the year of diagnosis to death, were 21.5, 15.8 and 6.8 years, respectively. There was 25 % of the silicosis patients whose survival time was beyond 33 y. The mean death age of all silicosis cases was 56.0 y. The death age increased to 65.6 y in the middle of 1990s. Among dust-exposed workers, subjects who became suspected case (0+ ) accounted for 15.0 %. 48.7 % of the suspected silicosis cases developed to silicosis, and the average year from the time of being suspected of the disease to the first stage of silicosis was 5.1 y. The natural characteristics, as mentioned above, varied with different mines and factories. We are led to conclude that silicosis is chronic in nature, but progress quickly. As a serious occupational disease it significantly reduces the life span of exposed workers. The study of its natural history is of importance for the development of health surveillance criteria for dust-exposed workers.

Abstract: Objective　To report a case of suppurative knee arthritis caused by Pasteurella multocida and review relevant literature to improve the awareness of the clinical physicians regarding this bacterium and provide reference for clinical diagnosis and treatment. Methods　A case of right knee suppurative arthritis caused by Pasteurella multocida was retrospectively reported and relevant literatures were reviewed in this article. Results　The infected person was a 76-year-old female patient with a 5-year history of intermittent pain in his right knee and suffered from joint swelling, aggravation pain, and limited flexion and extension activities after intraarticular injection of sodium hyaluronate. After admission and completing all necessary tests, the patient was later confirmed to have been infected with Pasteurella multocida. The patient's right knee was promptly examined and cleared under arthroscopic surgery, synovium and meniscus were excised, a drainage tube was inserted, and continuous joint cavity irrigation was performed after the surgery, and then ceftriaxone was injected and amoxicillin/clavulanate potassium was taken orally for anti-infection and the patient's condition improved significantly after 26 days. Conclusions　Pasteurella multocida infection cases are relatively rare, but the consequences in high-risk groups are relatively serious. Therefore, awareness of Pasteurella multocida and infection caused by it should be improved and high-risk groups should try to avoid contact with infectious sources as well as strengthen the management of pets so as to avoid infection.

Objective To investigate current situation of teaching competition and to put forward some feasible suggestions for improving the teaching competition of theoretical course for young teachers. Methods Questionnaire survey was conducted for 126 teachers including the effect of teaching competi-tion on effective teaching atmosphere,comprehensive teaching results,teaching ability and recommenda-tions for improvement. SPSS software was used to do statistical analysis andχ22 test was applied. P<0 . 05 stands for statistically significant difference. Results Investigation results demonstrated that teaching competition of theoretical course was conducive to forming effective teaching atmosphere,achieving better teaching effect and improving teaching ability of teachers . A χ22 test was performed on the cognition of the cultivating of classroom management ability;results demonstrated that there were significant differ-ences between teachers with more than 10 years education age and those with less than 10 years education age(χ22=4.375,P=0.0365). Conclusions Teaching competition of theoretical course is an effective way to cultivate young teachers teaching ability. Teaching competition should be combined with training and feedback and evaluation should be more scientific and objective in order to improve young teachers' teaching ability.

Objective:To explore the causes and preventive strategies of adverse reactions of blood transfusion in patients with hematological diseases.Methods:The clinical data of 150 hematological patients who received 5 184 cases of blood transfusion in Beijing No.6 Hospital from January 2014 to December 2017 were retrospectively analyzed. The blood transfusion adverse reaction reporting forms were collected, and the content of the form included the basic information of the patient, diagnosis, blood transfusion type, blood transfusion time, blood transfusion history, pregnancy history, adverse reaction history of blood transfusion as well as detailed records of clinical symptoms. The blood bank summarized the blood transfusion adverse reaction reporting forms every week.Results:A total of 112 cases of adverse reactions occurred in 5 184 cases of blood transfusion, the incidence rate was 2.16%. Sixty-eight cases (1.32%) had anaphylaxis, mainly caused by platelet transfusion, and 44 cases (0.85%) had fever, mainly caused by transfusion of red blood cells suspension, and no other adverse reactions were found. The incidence rates of adverse reactions of blood transfusion in patients with blood transfusion history and anaphylaxis history were significantly higher than those in patients without blood transfusion history and anaphylaxis history, and the differences were statistically significant [2.34% (102/4 350) vs. 1.20% (10/834), χ2 = 6.899, P = 0.009; 3.06% (98/3 200) vs. 1.42% (14/984), χ2 = 7.767, P = 0.005]; the incidence rate of adverse reactions of blood transfusion in female patients was significantly higher than that in male patients, and the difference was statistically significant [2.82% (60/2 126) vs. 1.70% (52/3 058), χ2 = 8.356, P = 0.004]; there was no significant difference in the incidence rate of adverse reactions of blood transfusion between patients < 18 years old and ≥ 18 years old [1.16% (3/259) vs. 2.21% (109/4 925), χ2 = 1.295, P = 0.255]. Conclusions:The main manifestations of adverse reactions of component blood transfusion are anaphylaxis and non-hemolytic fever. Clinical medical staff must carefully control the blood transfusion indications and select the appropriate blood components to reduce the adverse reactions of blood transfusion and ensure the safety of blood transfusion.

To provide a scientific basis for determining the health surveillance period of dust-exposed workers, data of a retrospective cohort study was re-analyzed with emphasis on natural course of silicosis. 33640 workers exposed to silica dust who were employed for at least 1 year from 1972 to 1974 in twenty Chinese mines or pottery factories were included as subjects, and were followed up till December 31, 1994. The cohort included subjects from 8 tungsten mines, 4 tin mines and 8 pottery factories. Our results showed that the mean latency of silicosis, for all the cases of the cohorts, was 22.9±9.8 y. 52.2 % of silicosis was diagnosed approximately 9. 1±5.7 y after the dust exposure had ceased. The progression rates of silicosis from stage Ⅰ to Ⅱ and from stage Ⅱ to Ⅲ were 48.2% and 18.5 %, and the duration was 4.1±0.2 and 6.8±0.2 y,respectively.The survival times of silicosis stage Ⅰ , Ⅱ and Ⅲ , from the year of diagnosis to death, were 21.5,15.8 and 6.8 years, respectively. There was 25 % of the silicosis patients whose survival time was beyond 33 y. The mean death age of all silicosis cases was 56.0 y. The death age increased to 65.6y in the middle of 1990s. Among dust-exposed workers,subjects who became suspected case (0+)accounted for 15.0%. 48.7% of the suspected silicosis cases developed to silicosis, and the aver age year from the time of being suspected of the disease to the first stage of silicosis was 5.1 y. The natural characteristics, as mentioned above, varied with different mines and factories. We are led to conclude that silicosis is chronic in nature, but progress quickly. As a serious occupational disease it significantly reduces the life span of exposed workers. The study of its natural history is of importance for the development of health surveillance criteria for dust-exposed workers.

Objective:To analyze the genetic mutation characteristics of glucose-6-phosphate dehydrogenase (G6PD) deficiency among infants in Kunming.Methods:A total of 15 533 infants (7 994 males and 7 539 females) born in Kunming from January 1, 2018, to December 31, 2020, with an age range of 2 to 44 days, were selected. G6PD enzyme activity and gene mutation types were detected using fluorescence quantitative analysis, multicolor melting curve analysis (MMCA), and Sanger sequencing. Droplet digital PCR (ddPCR) was used for quantitative analysis of a newly identified variant family to determine the mutant allele proportion in family members. Meanwhile,the protein structure model and pathogenicity prediction of the novel variant were analyzed.Data analysis was conducted using SPSS 26.0. Specifically, chi-square tests were used for the detection rates of G6PD enzyme activity and gene mutations between different genders. One-way analysis of variance (ANOVA) was used for the comparison of enzyme activity among different mutation types.Results:Among 15 533 infants, 143 cases (129 males and 14 females) were tested positive for G6PD activity, with a detection rate of 0.92% (143/15 533). The difference in detection rates between males and females was statistically significant (χ 2=96.76, P<0.001). Out of 89 enzyme activity-positive cases (83 males and 6 females) underwent genetic testing, 77 (72 males and 5 females) were detected by MMCAand other 12 negative samples were underwent further Sanger sequencing, revealing mutations in 6 samples, all of which were males. Among the 83 individuals with gene mutations, 78 had heterozygous mutations, 1 had a homozygous mutation, and 4 had compound heterozygous mutations. A total of 12 mutation types were detected, with G6PD c.487G>A, c.1024C>T, c.1388G>A, and c.1376G>T being the most common, accounting for 74.70% (62/83) of all mutation types. The average G6PD enzyme activity of c.1376G>T was the lowest, and the differences were statistically significant compared to the average enzyme activity of the other three mutations ( P<0.05). One male infant with a newly identified G6PD c.242G>C mutation was detected, predicted to be pathogenic. ddPCR confirmed that the mother of the affected child was a c.242G>C mutant chimera, with a chimera proportion of 6.66%. Conclusions:In the Kunming region, the predominant G6PD deficiency gene mutation is c.487G>A, with the detection of a novel G6PD c.242G>C mutation. The application of ddPCR technology can assist in detecting the proportion of mutation chimeras.