Machine learning for early prediction of in-hospital cardiac arrest in patients with acute coronary syndromes

Background

Previous studies have used machine leaning to predict clinical deterioration to improve outcome prediction. However, no study has used machine learning to predict cardiac arrest in patients with acute coronary syndrome (ACS). Algorithms are required to generate high‐performance models for predicting cardiac arrest in ACS patients with multivariate features.

Hypothesis

Machine learning algorithms will significantly improve outcome prediction of cardiac arrest in ACS patients.

Methods

This retrospective cohort study reviewed 166 ACS patients who had in‐hospital cardiac arrest. Eight machine learning algorithms were trained using multivariate clinical features obtained 24 h prior to the onset of cardiac arrest. All machine learning models were compared to each other and to existing risk prediction scores (Global Registry of Acute Coronary Events, National Early Warning Score, and Modified Early Warning Score) using the area under the receiver operating characteristic curve (AUROC).

Results

The XGBoost model provided the best performance with regard to AUC (0.958 [95%CI: 0.938–0.978]), accuracy (88.9%), sensitivity (73%), negative predictive value (89%), and F1 score (80%) compared with other machine learning models. The K‐nearest neighbor model generated the best specificity (99.3%) and positive predictive value (93.8%) metrics, but had low and unacceptable values for sensitivity and AUC. Most, but not all, machine learning models outperformed the existing risk prediction scores.

Conclusions

The XGBoost model, which was generated based on a machine learning algorithm, has high potential to be used to predict cardiac arrest in ACS patients. This proposed model significantly improves outcome prediction compared to existing risk prediction scores.

[Blood pressure control and influencing factors in hypertension patients with metabolic syndrome]

Objective: To investigate the blood pressure control and its influencing factors in hypertension patients with MS. Methods: Between January 2017 and December 2018, more than 78 000 residents aged 35-75 years selected through convenient sampling were invited to participant in China Patient-Centered Evaluative Assessment of Cardiac Event Million Persons Project in Fujian province, physical and laboratory tests were conducted for them, and their basic information were recorded. A total of 5 281 hypertension patients with MS were included in the study. Results: The treatment rate of hypertension patients with MS was 55.5%, and the control rate was 7.2%. The control rate was higher in patients who were older, women, had advanced education level, had history or family history of cardiovascular disease. The results of multivariate analysis indicated that living area (urban or rural), cardiovascular history, diabetes, urine protein, BMI had impacts on both treatment and control of hypertension. Family history of cardiovascular disease, age, self-management of hypertension, dyslipidemia, waist circumference and drinking had impacts on the treatments, and gender had effects on the control. Conclusions: The treatment rate of hypertension patients with MS was unsatisfactory and the control rate was low. Intervention should be strengthened in rural area, males and young age groups, and activity of self-management group of hypertension should be conducted regularly.

IL-22 relieves sepsis-induced liver injury via activating JAK/STAT3 signaling pathway

The purpose of this study was to investigate the influence of interleukin(IL)-22 on the Janus kinase/ signal transducer and activator of transcription 3 (JAK/STAT3) signaling pathway and sepsis-induced liver injury in rats. A total of 48 Sprague-Dawley rats were randomly divided into sham-operated group (n=12), model group (n=12), low-dose group (n=12) and high-dose group (n=12). Next, rat models of sepsis-induced liver injury were established through cecal ligation and puncture (CLP). At 12 h after surgery, blood was collected by heart puncture to detect liver function of the rats. It was found that the activity of alanine aminotransferase (ALT) and aspartame aminotransferase (AST) and the content of total bilirubin were reduced in low-dose group and high-dose group. Hematoxylin-eosin (HE) staining results revealed that after treatment with IL-22, the liver injury was relieved compared with model group. Moreover, the results of TUNEL staining assay revealed that the apoptosis level of liver cells declined after treatment with IL-22. Enzyme-linked immunosorbent assay (ELISA) results demonstrated that the levels of IL-6 and TNF-α were reduced, while the level of IL-10 was increased after treatment with IL-22. Moreover, it was discovered that the SOD content was overtly elevated in low-dose and high-dose groups compared with that in the model group. Finally, using Western blotting, it was confirmed that in comparison with the model group, the levels of Bcl-2/Bax and JAK/STAT3 signaling pathway-related proteins were markedly raised, while the level of Caspase-3 was decreased in the low-dose and high-dose groups. In conclusion, IL-22 can improve liver function, reduce the apoptosis level of liver cells, the expression of apoptosis-related proteins and the release of inflammatory factors, and alleviate liver injury by activating the JAK/STAT3 signaling pathway.

[Exploration of the treatment model for patients with advanced non-small cell lung cancer complicated with chronic obstructive pulmonary disease based on real-world data]

Objective: To explore whether combining treatment of chronic obstructive pulmonary disease (COPD) with anti-tumor therapy is better than that of tumor treatment alone in advanced non-small cell lung cancer (NSCLC) patients with COPD in the real world. Methods: The clinical data of 101 patients with advanced NSCLC complicated with COPD from January 1, 2015, to December 31, 2017, in the First Affiliated Hospital of Guangzhou Medical University were analyzed retrospectively, including 99 males and two females, aged from 52 to 84 years[average (67±8) years]. Among the patients, 90 (89.1%) were smokers, with an average pack-year smoking index of (47±4) . The patients were divided into observation and control groups, depending on whether they received standardized anti-COPD supportive treatment. In the observation group, there were 36 patients, including 35 males and one female, aged from 54 to 84 years[ average (67±8) years], with an average pack-year of smoking (47±4). There were 65 patients in the control group, including 64 males and one female, aged from 52 to 83 years [average (67±8) years], with an average pack-year of smoking 47±4. There was no significant difference in the baseline data between the two groups. The primary outcome measures included the Objective response rate (ORR), disease control rate (DCR), disease-free survival (PFS), and overall survival (OS) of the two groups. An unpaired t-test was used to compare continuous variables between the observation and control groups. The Pearson chi-square test was used to compare categorical variables between the two groups. Kaplan-Meier survival curves were used to evaluate the median PFS and median OS of patients, and the log-rank test was used to assess differences between groups. Result: The ORR of the observation group and the control group was 22.6% (7 cases) and 22.2% (11 cases), respectively, with no significant difference (χ(2)=0.01, P=0.971). The DCR between the observation group and the control group was 58.1% (19 cases) and 57.8% (27 cases), with no significant difference (χ(2)=0.02, P=0.889). Median PFS in the observation group was 6.0 months, which was better than the 3.5 months in the control group (χ(2)=3.947, P<0.05). The median OS of the observation group was 18.0 months, which was better than the 15.0 months of the control group (χ(2)=4.083, P<0.05). Conclusions: Compared with the treatment of tumors alone, combination of anti-tumor therapy with anti-COPD therapy showed longer PFS and OS in patients with advanced NSCLC complicated with COPD.

[Association of Crohn's disease with aryl hydrocarbon receptor gene polymorphisms and haplotypes]

Objective: To explore the relationship of Crohn's disease (CD) susceptibility to aryl hydrocarbon receptor (AhR) polymorphisms and haplotypes in Han population in Wenzhou city, China. Methods: A total of 310 CD patients and 573 age- and sex-matched healthy controls were enrolled in our study. Three single nucleotide polymorphisms (SNPs) of AhR(rs10249788,rs2158041,rs2066853) were determined by the improved multiple ligase detection reaction technique. Unconditional logistic regression analyses was applied to analyze the allelic and genotypic differences of each SNP between CD patients and controls, as well as their influence on the clinicopathologic characteristics in CD patients. Analyses of linkage disequilibrium and haplotype were performed by Haploview 4.2 software in all study subjects. Results: Compared with the controls, the variant allele (T) and genotype (CT+TT) of (rs2158041) were evidently decreased among CD patients (19.52% vs. 25.04%, P=0.009; 34.19% vs. 44.68%, P=0.003). According to "the Montreal Classification Standards" , CD patients were divided into different subgroups. The variant allele (T) and genotype (CT+TT) of (rs2158041) were significantly lower in patients with terminal ileum CD than in controls (16.79% vs. 25.04%, P=0.005; 28.24% vs. 44.68%, P=0.001). Similar conclusions were also drawn in patients with constricting disease when compared with the controls (15.20% vs. 25.04%, P=0.003; 28.43% vs. 44.68%, P=0.003). The three SNPs above were shown to be in a linkage disequilibrium. Compared with the controls respectively, the frequency of haplotype (CCG) was increased in CD patients (44.73% vs. 39.60%, P=0.039), whereas that of haplotype (CTG) was decreased (18.02% vs. 22.78%, P=0.047). Conclusions: AhR (rs2158041) variation might influence the risk as well as the location and behavior of CD. The haplotype (CCG) possibly increase the risk of CD development, whereas haplotype (CTG) might decrease it.

[Clinical analysis of 36 cases of advanced non-small cell lung cancer (NSCLC) with performance status (PS) scores between 2 and 4]

Objective: To analyze the treatment of advanced non-small cell lung cancer (NSCLC) with performance status (PS) scores between 2 and 4, in order to improve the diagnosis and treatment of these patients. Methods: A total of 36 patients with advanced NSCLC with hypoxemia were reviewed. The clinical data of disease characteristics, etiology, complications, manifestation, therapy, progression, and secondary biopsy were collected. The clinical efficacy was graded according to the Response Evaluation Criteria In Solid Tumors (RECIST): complete response (CR), partial response (PR), stable disease (SD) and disease progression (PD). Results: All patients had hypoxemia, of whom 86.1% (31 patients) had complications and 55.6% (20 patients) had noninvasive ventilator for respiratory support. 77.8% (28 cases) received broad-spectrum antibiotic treatment, and 78.6% of them got lung osmotic relief after the anti-infection treatment. 15 cases received bedside fiberoptic bronchoscopy suction, of whom two cases were treated with airway stent deposition due to airway obstruction, four cases with thoracic drainage, four cases with anticoagulation, and one with thrombolytic therapy. After these supportive treatment, the PS score of these patients decreased from 3.4±0.5 to 2.5±0.7, while SPO(2) improved from (89.0±5.2)% to (95.0±3.5)%. As first-ling anti-cancer treatment, nine patients were administrated with targeted medicine orally, 13 patients with a combined chemotherapy of pemetrexed plus bevacizumab or carboplatin, eight patients with paclitaxel plus carboplatin, four patients with gemcitabine plus carboplatin, and two patients with docetaxel plus gemcitabine. In the first response evaluation, there were one case of CR, 23 cases of PR, four cases of SD, and eight cases of PD, with a clinical benefit rate of 66.7% and a disease control rate of 77.8%. A total of 22 patients experienced disease progression, of whom eight cases had a secondary biopsy and six cases had gene sequencing. Of these 36 patients, 10 (27.8%) patients survived at the last follow-up, with a progression-free survival of (10.0±6.5) months. Conclusion: Besides prompt anti-cancer treatment and best supportive treatment should be incorporated to improve PS and improve outcome.

[Association of ulcerative colitis with fork head/winged helix transcription factor-3 gene polymorphisms in Chinese patients]

Objective: To investigate the association of ulcerative colitis (UC) with fork head/winged helix transcription factor-3 (Foxp3) polymorphisms in Han population in Zhejiang province, China. Methods: A total of 381 UC patients and 490 healthy controls were enrolled in this study.The four single nucleotide polymorphisms (SNPs) of Foxp3 (rs3761547, rs2232365, rs2294021, rs3761548) were examined by SNaPshot.The analyses of linkage disequilibrium (LD) and haplotype were also performed in all study subjects. Results: When male and female UC patients were compared with their corresponding controls respectively, the alleles and genotypes of the four SNPs were not statistically different (all P>0.05). According to severity and location of the disease, the UC patients were divided into different subgroups. The alleles (C, G, A) of (rs2232365, rs2294021, rs3761548) were more frequent in male patients with severe UC than in the male controls (69.6% vs 34.3%, P=0.001; 69.6% vs 34.3%, P=0.001; 39.1% vs 14.4%, P=0.002, respectively). As compared with the female controls, the alleles (C, G, A) and genotypes (TC+ CC, AG+ GG, CA+ AA) of (rs2232365, rs2294021, rs3761548) were significantly increased in the female patients with severe UC (51.9% vs 38.0%, 63.5% vs 39.2%, 53.8% vs 21.4%, 80.8% vs 57.7%, 84.6% vs 58.4%, 76.9% vs 34.7%, all P<0.05). The four SNPs above were shown to be in a strong LD both in male and in female subjects.When male and female UC patients were compared with their corresponding controls respectively, nevertheless, each haplotype frequency was not statistically different (all P>0.05). Conclusions:Foxp3 (rs2232365, rs2294021, rs3761548) variations might engender the increased risk of severe UC in Chinese Han patients.

[Association between high expression of intrahepatic programmed death-1 and liver inflammation in patients with autoimmune hepatitis]

Objective: To investigate the expression of programmed death-1 (PD-1) in liver tissue and its association with liver pathology in patients with autoimmune hepatitis (AIH). Methods: A total of 54 AIH patients (38 in the active stage and 16 in the remission stage) were enrolled, and 9 healthy volunteers were enrolled as control group. Immunohistochemistry combined with quantitative image analysis was used to measure the expression of PD-1 in liver tissue. The t-test, rank sum test, one-way analysis of variance, least significant difference t-test, Mann-Whitney U test, and Pearson relation analysis were used for statistical analysis of different types of data. Results: The AIH group had a significantly higher positive rate of PD-1 in liver tissue than the control group (13.57%±6.84% vs 2.22%±0.66%, P < 0.01), and the patients in the active stage of AIH had a significantly higher positive rate of PD-1 in liver tissue than those in the remission stage (16.53%±7.72% vs 6.56%±3.16%, P < 0.01). The positive rate of PD-1 in liver tissue was 6.56%±3.16% in G0 group, 14.33%±5.08% in G1-2 group, and 19.23%±5.41% in G3-4 group (P < 0.01), but there was no significant difference in the positive rate of PD-1 between S0, S1-2, and S3-4 groups (P > 0.05). In AIH patients, the positive rate of PD-1 in liver tissue was positively correlated with the levels of total bilirubin, alanine aminotransferase, aspartate aminotransferase, and IgG (r = 0.665, 0.721, 0.711, and 0.813, all P < 0.01). Conclusion: AIH patients have regulated PD-1 expression in liver tissue, which is closely associated with liver inflammation and is not associated with fibrosis degree, suggesting that PD-1 is involved in the development and progression of inflammation in AIH patients.

[Estimation of underreporting rate of death cases in disease surveillance system of Fujian province using propensity score weighting method, 2012-2014]

Objective: To understand the underreporting of death cases and related factors in disease surveillance system of Fujian province. Methods: We carried out a field underreporting survey in 20 disease surveillance sites selected through stratified cluster random sampling during 2012-2014. The related factors of underreporting were analyzed by using logistic regression method. Propensity score weighting method was used to calculate the underreporting rate in different groups classified by year, urban/rural areas, gender, age and death cause variables. Results: The overall underreporting rate was 9.21%(95%CI: 9.06%-9.39%) after adjusting by propensity score weighting method. The underreporting rate was higher in rural area (11.55%, 95%CI: 11.30%-11.81%) than in urban area (6.64%, 95%CI: 6.50%-6.78%). The underreporting rate was highest in age group 0-14 years (36.29%, 95% CI: 34.23%-38.67%) and lowest in age group ≥65 years (7.91%, 95% CI: 7.78%-8.03%). The underreporting rate was higher in people died of perinatal disease, congenital anomalies and injury. Conclusion: The underreporting rates were different between different groups classified by urban/rural areas, age and death cause variables. Propensity score weighting method can be used to adjust underreporting rate of death cases in mortality surveillance in Fujian.

[Association of Crohn's disease with transcobalamin Ⅱ gene polymorphisms and serum homocysteine, folate and vitamin B12 levels in Chinese patients]

OBJECTIVE

To investigate the association of Crohn's disease (CD) with transcobalamin Ⅱ (TCN2) gene polymorphisms and serum homocysteine (Hcy), folate, and vitamin B12 levels in Chinese patients.

METHODS

In a total of 307 CD patients (CD group) and 574 healthy controls (control group) of Han ethnicity selected at 4 hospitals in Wenzhou between January 2007 and August 2015, TCN2 gene polymorphisms (rs1801198, C/G; rs9606756, A/G) in peripheral blood were determined using improved multiple ligase detection reaction (iMLDR). The Simplified Crohn's Disease Activity Index (CDAI) was applied to evaluate activity of CD. Eighty-eight CD patients and 138 age- and sex-matched controls were randomly selected from all the study subjects using computer-generated random numbers, in whom serum Hcy level was tested by enzymatic cycling assay, folate and vitamin B12 levels were examined by chemiluminescence immunoassay.

RESULTS

(1) The mutant allele (G) and genotype (CG+ GG) of rs1801198 were not significantly different between the CD group and the control group (both P>0.05), but more prevalent in patients with stricturing CD than in controls (65.75% vs 56.10%, 93.15% vs 82.40%, both P<0.05). The frequencies of mutant allele (G) and heterozygous genotype (AG) of rs9606756 were higher in CD patients than in controls (2.44% vs 1.05%, 4.89% vs 2.09%, both P<0.05), also higher in patients with stricturing CD or ileocolonic CD compared with controls (stricturing CD: 4.79% vs 1.05%, 9.59% vs 2.09%; ileocolonic CD: 3.18% vs 1.05%, 6.36% vs 2.09%; all P<0.05). The two polymorphic loci (rs1801198 and rs9606756) were shown to be in a weak linkage disequilibrium. The frequency of haplotype (GG) was higher in the CD patients than in the controls (2.23% vs 0.81%, P<0.05). (2) When compared with the controls, the serum Hcy level was higher in the CD patients (P=0.023), whereas the folate and vitamin B12 levels were decreased in the CD patients (both P<0.001). The prevalence of hyperhomocysteinemia (Hcy >15 μmol/L), folate deficiency (folate <4 μg/L) and vitamin B12 deficiency (<203 ng/L) were higher in the CD patients than in the controls (18.18% vs 4.35%, 27.27% vs 5.07%, 31.82% vs 5.07%, all P<0.01). Compared to the patients at remission stage (CDAI<5), the serum Hcy level was increased in those at active stage (CDAI≥5) (P=0.005), while the folate and vitamin B12 levels were decreased in the patients ate active stage (both P<0.05). (3) According to the results of multivariate linear regression analysis, average Hcy level in the CD patients was negatively associated with folate level (β=-0.494, P<0.001), while positively correlated with percentage of neutrophils (β=0.294, P=0.004). Unconditional Logistic regression showed that both folate deficiency and vitamin B12 deficiency were independent risk factors for CD (OR=5.415, OR=7.112, both P<0.001).

CONCLUSIONS

TCN2 rs1801198 mutation might be associated with increased risk of stricturing CD. TCN2 rs9606756 mutation might be a potential functional locus to affect CD susceptibility. Individuals carrying the haplotype (GG) formed by TCN2 (rs1801198 and rs9606756) seem to be at higher risk of developing CD. Hyperhomocysteinemia, folate deficiency, and vitamin B12 deficiency are prevalent in this cohort of CD patients of Han ethnicity from Zhejiang province. Both folate deficiency and vitamin B12 deficiency are independent risk factors for CD.

Recent Chlamydia pneumoniae infection is highly associated with active ankylosing spondylitis in a Chinese cohort

OBJECTIVE

The aim of the present study was to investigate the presence of anti-Chlamydia pneumoniae (Cp) antibodies in patients with ankylosing spondylitis (AS) to determine whether there is an association with AS disease activity.

METHODS

Seventy-nine AS outpatients and 73 normal controls were enrolled in this case-control study. Serum anti-Cp immunoglobulins (CpIg) were detected by enzyme-linked immunosorbent assay (ELISA). Antibodies to Epstein-Barr virus (EBV), cytomegalovirus (CMV), and Chlamydia trachomatis (Ct) were also measured. Clinical and experimental data were collected, and the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) was determined. Patients with positive Cp IgM or Cp IgA were considered to have had a recent Cp infection.

RESULTS

Cp IgG was detected in the majority of AS patients and also controls (88.8% vs. 91.8%, respectively). The seroprevalence of Cp IgA and Cp IgM was significantly higher in AS patients than in the controls (51.9% vs. 31.5%, p = 0.010 for Cp IgA; 79.7% vs. 20.5%, p < 0.0001 for Cp IgM). Seropositivity of Cp IgM was associated with elevation of the disease activity index, including erythrocyte sedimentation rate (ESR; p = 0.021), C-reactive protein (CRP; p = 0.007) and the BASDAI (p = 0.009). Persistent positive Cp IgM was associated with active disease, while seroreversion of Cp IgM was associated with a reduction in these disease activity indices. There was no correlation between Cp IgM or Cp IgA and symptomatic upper respiratory infections or other clinical manifestations.

CONCLUSIONS

Recent Cp infections occur frequently in AS patients and Cp IgM antibody is correlated with active disease. These findings indicate that Cp infections may be a triggering factor for active AS.

Comparison of genomic and predicted amino acid sequences of respiratory and enteric bovine coronaviruses isolated from the same animal with fatal shipping pneumonia

The complete genome sequences are reported here of two field isolates of bovine coronavirus (BCoV), which were isolated from respiratory and intestinal samples of the same animal experiencing fatal pneumonia during a bovine shipping fever epizootic. Both genomes contained 31028 nucleotides and included 13 open reading frames (ORFs) flanked by 5'- and 3'-untranslated regions (UTRs). ORF1a and ORF1b encode replicative polyproteins pp1a and pp1ab, respectively, that contain all of the putative functional domains documented previously for the closest relative, mouse hepatitis virus. The genomes of the BCoV isolates differed in 107 positions, scattered throughout the genome except the 5'-UTR. Differences in 25 positions were non-synonymous and were located in all proteins except pp1b. Six replicase mutations were identified within or immediately downstream of the predicted largest pp1a-derived protein, p195/p210. Single amino acid changes within p195/p210 as well as within the S glycoprotein might contribute to the different phenotypes of the BCoV isolates.

Pre-concentration of non-uniform field electrophoresis for sample introduction of capillary electrophoresis

A new sample introduction method of capillary electrophoresis, in which field-amplified sample injection was combined with a pre-concentration of non-uniform field electrophoresis, is presented in this paper. With an additional pre-concentration voltage applied to sample solution, a non-uniform electric field was generated, with which analytical cations or anions were pre-concentrated around an electrode adjacent to the injection end of capillary. After the pre-concentration, analytical ions were injected into the capillary and stacked at the boundary between sample and buffer solution inside capillary by field-amplified injection technique. In contrast to the conventional field-amplified injection, larger concentration factor and higher analytical sensitivity were obtained with the improved pre-concentration method. Its concentration factor was about 10 approximately 15 fold as that of field-amplified sample injection.

[Study on sampling preconcentration method combining electrostacking with isotachophoresis in capillary electrophoresis]

A sampling preconcentration method combining electrostacking with isotachophoresis is presented in this paper. The optimum conditions for electrostacking and isotachophoresis were investigated. With the preconcentration conditions of 70 s electrostacking and 40 s isotachophoresis, two medicines, propranolol and metoprolol, with similar structures were separated by capillary zone electrophoresis. The working voltage for all the steps was 15 kV. Being adjusted to pH 4.0, 30 mmol/L NaAc-HAc, 30 mmol/L beta-alanine-HAc and 1.5 mmol/L NaAc-HAc were employed as the background, viz. leading, terminating and sample buffer solutions respectively. In comparing with the conventional electro-migration injection, the enhancement factors in peak height of the present method were about 250 and 160 for propranolol and metoprolol respectively. Total analysis time was similar to that of the conventional one.

Temperature-sensitive acetylesterase activity of haemagglutinin-esterase specified by respiratory bovine coronaviruses

Numerous respiratory bovine coronaviruses (RBCV) were isolated recently from nasal swab samples and lung tissues of feedlot cattle with acute respiratory tract disease. These newly emerging RBCV isolates exhibited distinct phenotypic features that differentiated them from enteropathogenic bovine coronaviruses (EBCV). The RBCV strains had a receptor-destroying enzyme function mediated by acetylesterase (AE) activity of the haemagglutinin-esterase (HE) glycoprotein. The HE genes of wild-type EBCV strain LY138 and RBCV strains OK-0514 (OK) and LSU-94LSS-051 (LSU) were cloned, sequenced and transiently expressed in COS-7 cells. The enzymic properties of HE proteins in COS-7 cellular extracts and in purified virus preparations were assayed at room temperature, 37 degrees C and 39 degrees C by two different assays. One assay used p-nitrophenyl acetate (PNPA) as substrate and detected serine-esterase activity; the second assay monitored AE function with bovine submaxillary mucin (BSM) as substrate. The PNPA tests confirmed that HE proteins of EBCV and RBCV were functionally expressed in transfected COS-7 cells. Time-dependent determination of the AE activity of purified RBCV OK and LSU particles showed lower AE activity at 39 degrees C than at 37 degrees C, whereas the purified EBCV LY particles retained full AE activity at both 37 degrees C and 39 degrees C. Transiently expressed RBCV HE exhibited a marked reduction of AE activity after 40 min of assay time at 37 degrees C. In contrast, the AE activity of the transiently expressed EBCV HE remained stable beyond 40 min. The deduced amino-acid sequences of the HE proteins specified by the RBCV strains OK and LSU contained specific amino-acid changes in comparison with the EBCV LY strain, which may be responsible for the observed enzymic differences. These results are consistent with the hypothesis that RBCV strains have evolved to selectivelyreplicate in respiratory tissues and that HE may play a role in this tissue tropism.

Long-lasting chemiluminescence of luminol on electrochemically pre-oxidized platinum electrodes in NaOH solution

A long-lasting bright chemiluminescence (CL) of luminol was generated at polycrystalline platinum electrodes with open circuit. The CL can last for several hours with the presence of O(2) in the solution when the electrode was preoxidized at potentials more positive than 1.10 V vs. SCE. The effects of the varieties of solution conditions and surface states of the electrode on the CL intensity and the interfacial potential of the electrode were investigated. It was proposed that PtO was generated at the pre-oxidized potentials and played a role of catalyst of luminol oxidation for generating the CL. The redox couple of PtO/Pt(active) at the electrode surface was maintained in the presence of O(2) and luminol, and generated the interfacial potential more positive than 140 mV. Mathematical treatment of the reaction mechanism was conducted, which led to an approximated expression of a steady CL intensity (I(CL)) as a function of the pre-polarization potential (E( h)) and time (tau( h)) of the electrode. An empirical equation, (I(CL))(4/3) = 3480(-1 + 0.82E( h) + 0.037 ln tau( h)), was estimated from the experimental data.

Antibody responses to respiratory coronavirus infections of cattle during shipping fever pathogenesis

Antibody responses against respiratory bovine coronavirus (RBCV) infections were monitored in cattle from the onset of a naturally occurring severe shipping fever (SF) epizootic to complete recovery of affected cattle or fatal outcomes. The infection with RBCV was detected in nasal secretions of 86 cattle, and 81 of them developed acute respiratory tract disease, including fatal pneumonia. Cattle nasally shedding RBCV at the beginning of the epizootic experienced characteristic primary immune responses with specific antibodies for hemagglutinin-esterase (HE) and spike (S) glycoproteins. Virus shedding in nasal secretions of the majority of the cattle ceased between days 7 and 14 with the appearance of HE- and S-specific antibodies. Nasal samples and lung tissues from 9 of the 10 fatal cases had high titers of RBCV, but these cattle had only IgM responses to RBCV infections. Cattle remaining negative in RBCV isolation tests entered this epizootic with antibodies against HE and S. Protection against respiratory tract disease was apparently associated with high level of opsonic and virus-neutralizing IgG2. The HE and S glycoproteins were recognized earliest by the bovine immune system while the N protein induced antibody responses during the later stage of initial infection and the early stage of reinfection. The membrane (M) glycoprotein was the least immunogenic of the major viral structural proteins.

[Determination of the contents of mineral elements in the soil where the jinin big-wild ginseng grows]

The element contents in the soil where the Jilin Big-Wild Ginseng grows were determined with plasma emission spectrometry. 23 elements in the soil were found, of which 12 are macro and trace elements indispensable to Ginseng growth. This study provides a scientific basis for selecting suitable soil for planting wild ginseng, or for creating optimum soil conditions for the bumper harvest and high quality of Ginseng.