Safety and efficacy of restarting immune checkpoint inhibitors in non-small cell lung cancer patients following immune-related adverse events: a systematic review and meta-analysis.

OBJECTIVE: This meta-analysis aims to evaluate the safety and efficacy of restarting immune checkpoint inhibitors (ICIs) in patients with non-small cell lung cancer (NSCLC) after experiencing immune-related adverse events (irAEs). METHODS: A comprehensive search of PubMed, Web of Science, Embase, and the Cochrane Library was conducted to identify studies investigating the safety and efficacy of restarting ICIs in NSCLC patients after irAEs. Outcome measures, including objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) after ICI restarting, were extracted. Meta-analysis was performed using the R meta-package. RESULTS: Four studies involving a total of 326 subjects were included, comprising 137 patients who restarted ICI treatment after irAEs and 189 patients who did not restart ICI treatment. The results revealed that ICI restarting was associated with an increased ORR (OR = 2.36, 95% CI 1.49-3.84), prolonged PFS (HR = 0.60, 95% CI 0.42-0.86), and prolonged OS (HR = 0.65, 95% CI 0.43-0.99) compared to non-restarting. The incidence of irAEs after ICI restarting was 45% (95% CI 0.27-0.63). CONCLUSION: Restarting ICI treatment after discontinuation due to previous irAEs appears to be a reasonable option for NSCLC patients. However, a comprehensive assessment of the potential benefits and risks to individual patients is crucial, and close monitoring of irAEs is warranted.

The effect of narrative nursing on improving the negative emotions and quality of life of patients with moderate to severe cancer pain.

OBJECTIVE: This study aimed to explore the effect of narrative nursing on improving the negative emotions, sleep quality, and quality of life of patients with moderate to severe cancer pain. METHODS: A total of 80 patients with moderate to severe cancer pain who had been hospitalized in the lymphoma oncology department in our hospital from March 2019 to September 2021 were selected as the study subjects and randomly divided into the conventional nursing and narrative nursing groups, with 40 cases in each group. A conventional nursing intervention was conducted for one group, and narrative nursing was provided for the second group in addition to the conventional nursing. The anxiety and depression, sleep quality, quality of life, and satisfaction with pain management of the patients in the two groups were compared before and after the intervention. RESULTS: In the narrative nursing group, the self-rating anxiety scale and self-rating depression scale scores were significantly lower than those in the conventional nursing group after the intervention (P < 0.05). The scores for sleep quality, sleep duration, sleep efficiency, and daytime dysfunction and the total Pittsburgh Sleep Quality Index scores were significantly lower in the narrative nursing group compared with the conventional care group (P < 0.05). The scores for the physical function, living ability, social adaptation, and psychological status items in the Quality of Life Questionnaire Core 30 were significantly higher in the narrative nursing group than in the conventional care group (P < 0.05). The patients' satisfaction with pain management was higher in the narrative nursing group than in the conventional care group (P < 0.05). CONCLUSION: Narrative nursing can alleviate the negative emotions of anxiety and depression in patients with moderate to severe cancer pain and improve their sleep quality, quality of life, and pain management satisfaction.

Efficacy and safety of anlotinib plus anti-PD-1 agents in patients with refractory advanced biliary tract cancers.

BACKGROUND: Anlotinib has demonstrated promising anti-tumor efficacy in various solid tumors. Additionally, there is evidence suggesting that immune therapy can enhance the systemic responses of anlotinib. This study aimed to assess the effectiveness and safety of combining anlotinib with PD-1 inhibitors compared to fluoropyrimidine-based chemotherapy as a second-line treatment option for advanced biliary tract cancers (BTCs). METHODS: A total of 242 patients with BTCs were screened at the First Affiliated Hospital of Zhengzhou University from October 2015 to October 2022. Among them, 78 patients who received either anlotinib plus PD-1 inhibitors (AP) or fluoropyrimidine-based chemotherapy (FB) as second-line treatment were included in the study. The primary endpoint was progression-free survival (PFS), and the secondary endpoints included objective response rate (ORR), disease control rate (DCR), overall survival (OS), safety, and predictive tumor biomarkers. RESULTS: Among the 78 patients with BTCs, 39 patients received AP, while 39 patients were administered FB. The ORR in the AP group was 20.5%, compared to 5.1% in the FB group. The DCR was 87.2% in the AP group and 66.7% in the FB group. The AP group demonstrated significantly better ORR and DCR compared to the FB group (p = 0.042, p = 0.032). The median PFS and OS in the AP group were 7.9 months (95% CI: 4.35-11.45) and 13.9 months (95% CI: 5.39-22.41), respectively. In the FB group, the median PFS and OS were 4.1 months (95% CI: 3.17-5.03) and 13.2 months (95% CI: 8.72-17.68), respectively. The AP group exhibited significantly better median PFS than the FB group (p = 0.027). In the subgroup analysis, patients without liver metastasis had a much longer PFS in the AP group compared to the FB group (14.3 vs. 5.5 months, p = 0.016). Similarly, patients with CEA ≤ 5 µg/L also demonstrated a longer PFS in the AP group compared to the FB group (8.7 vs. 3.9 months, p = 0.008). CONCLUSIONS: The combination of anlotinib and PD-1 inhibitors demonstrated a promising clinical effect compared to fluoropyrimidine-based chemotherapy in the second-line treatment of refractory advanced BTCs. Liver metastases and CEA levels may serve as predictive factors for identifying patients who may benefit from AP therapy.

Genomic sequencing revealed recombination event between clade 1 and clade 2 occurs in circulating varicella-zoster virus in China.

Varicella-zoster virus (VZV), a member of the Alphaherpesvirinae subfamily, causes varicella in primary infections and establishing a latent stage in sensory ganglia. Upon reactivation, VZV causes herpes zoster with severe neuralgia, especially in elderly patients. The mutation rate for VZV is comparatively lower than the other members of other alpha herpesviruses. Due to geographic isolation, different genotypes of VZV are circulating on separate continents. Here, we successfully isolated a VZV from the vesicular fluid of a youth zoster patient. Based on the single-nucleotide polymorphism profiles of different open reading frames that define the genotype, this newly isolated VZV primarily represents genotype clade 2 but also has characteristics of genotype clade 1. The next-generation sequencing provided a nearly full-length sequence, and further phylogenetic analysis revealed that this VZV isolate is distinct from clades 1 and 2. The Recombination Detection Program indicates that a possible recombinant event may occur between the VZV isolate and clade 1. In summary, we found that there is a circulating VZV isolate in China that may represent a recombinant between clade 1 and clade 2, providing new concerns that need to be considered in the future VZV vaccination program.

Effect of obesity, lipids and adipokines on allergic rhinitis risk: a Mendelian randomization study

Abstract Objectives: Observational studies suggested that obesity may promote the development of allergic rhinitis. The aim of this study was to explore the association of obesity, lipids and adipokines with this allergic disease at the genetic level using Mendelian randomization strategies. Methods: Summary data for three obesity indicators (such as body mass index), eight lipid indicators (such as triglycerides) and six adipokines (such as interleukin-6 and adipocyte fatty acid-binding protein) were collected, and suitable instrumental variables were extracted from these summary data according to the three main assumptions of Mendelian randomization. Three Mendelian randomization methods (such as inverse variance weighted) were used to detect the casual effect of the above indicators on allergic rhinitis risk. Sensitivity analyses were performed to assess heterogeneity and horizontal pleiotropy. Results: After Bonferroni correction, the inverse variance weighted reported that elevated levels of interleukin-6 and adipocyte fatty acid-binding protein were nominally associated with the decreased risk of allergic rhinitis (OR = 0.870, 95% CI 0.765-0.990, p = 0.035; OR = 0.732, 95% CI 0.551-0.973, p = 0.032). The other Mendelian randomization methods supported these results. Obesity, lipids and other adipokines were not related to this allergic disease. Sensitivity analyses found no heterogeneity and horizontal pleiotropy in the study. Conclusion: The study provided some interesting, but not sufficient, evidence to suggest that interleukin-6 and adipocyte fatty acid-binding protein might play a protective role in the development of allergic rhinitis at the genetic level. These findings should be validated by more research. Level of evidence: This was a Mendelian randomized study with a level of evidence second only to clinical randomized trials, and higher than cohort and case-control studies.

Effect of obesity, lipids and adipokines on allergic rhinitis risk: a Mendelian randomization study.

OBJECTIVES: Observational studies suggested that obesity may promote the development of allergic rhinitis. The aim of this study was to explore the association of obesity, lipids and adipokines with this allergic disease at the genetic level using Mendelian randomization strategies. METHODS: Summary data for three obesity indicators (such as body mass index), eight lipid indicators (such as triglycerides) and six adipokines (such as interleukin-6 and adipocyte fatty acid-binding protein) were collected, and suitable instrumental variables were extracted from these summary data according to the three main assumptions of Mendelian randomization. Three Mendelian randomization methods (such as inverse variance weighted) were used to detect the casual effect of the above indicators on allergic rhinitis risk. Sensitivity analyses were performed to assess heterogeneity and horizontal pleiotropy. RESULTS: After Bonferroni correction, the inverse variance weighted reported that elevated levels of interleukin-6 and adipocyte fatty acid-binding protein were nominally associated with the decreased risk of allergic rhinitis (OR = 0.870, 95% CI 0.765-0.990, p = 0.035; OR = 0.732, 95% CI 0.551-0.973, p = 0.032). The other Mendelian randomization methods supported these results. Obesity, lipids and other adipokines were not related to this allergic disease. Sensitivity analyses found no heterogeneity and horizontal pleiotropy in the study. CONCLUSION: The study provided some interesting, but not sufficient, evidence to suggest that interleukin-6 and adipocyte fatty acid-binding protein might play a protective role in the development of allergic rhinitis at the genetic level. These findings should be validated by more research. LEVEL OF EVIDENCE: This was a Mendelian randomized study with a level of evidence second only to clinical randomized trials, and higher than cohort and case-control studies.

Enhancing medical ethics education for medical students in clinical research: considerations and strategy analysis / Mejorando la educación ética médica para los estudiantes de medicina en la investigación clínica: consideraciones y análisis de estrategias / Melhorando a educação de ética médica para estudantes de medicina em pesquisa clínica: pensamentos e análise de estratégia

In recent years, the vigorous development of clinical researches carried out by medical schools is inseparable from the effective participation of medical students. However, as the number and categories of clinical research projects that medical students participate in increase, medical ethics related issues gradually occur. This article sorts out the ethical issues that arose in clinical researches, in which medical students participated, analyzes the underlying causes, and proposes solutions for the above-mentioned ethical issues, aiming to provide reference for medical ethics education and research project management for medical schools.

La participación efectiva de los estudiantes de medicina ha contribuido en gran medida al desarrollo exitoso de la investigación clínica en las escuelas de medicina de China en los últimos años. Sin embargo, con el creciente número y tipos de proyectos de investigación clínica en los que participan estudiantes de medicina, las cuestiones éticas se exponen gradualmente. Este trabajo enumera las cuestiones éticas que han surgido en la participación de los estudiantes de medicina en la investigación clínica en los últimos años, analiza las causas subyacentes y propone soluciones a las cuestiones éticas mencionadas anteriormente, con el objetivo de proporcionar referencia para la enseñanza de la ética médica y la gestión de proyectos de investigación para las escuelas de medicina.

A participação efetiva dos estudantes de medicina tem contribuído muito para o próspero desenvolvimento da pesquisa clínica nas escolas médicas da China nos últimos anos. No entanto, com o aumento do número e tipos de projetos de pesquisa clínica dos quais os estudantes de medicina participam, questões relacionadas à ética e à alfabetização são gradualmente expostas. Este artigo lista as questões éticas que surgiram na participação de estudantes de medicina em pesquisas clínicas nos últimos anos, analisa as causas subjacentes e propõe soluções para as questões éticas acima mencionadas, com o objetivo de fornecer referência para o ensino de ética médica e gestão de projetos de pesquisa para escolas médicas.

Comparative study of the histomorphological structure of the small intestine of Lonchura striata and Copsychus saularis / Estudio comparativo de la estructura histomorfológica del intestino delgado de Lonchura striata y Copsychus saularis

SUMMARY: Six Lonchura striata and six Copsychus saularis birds were selected in this study, morphological index of the small intestine was measured by quantitative biology and image analysis. The changes of goblet cells and Na+/K+ATPase were detected by AB-PAS staining and ELISA to inform the different mechanisms of the digestion and absorption of nutrients between the Lonchura striata and Copsychus saularis. The villus height, crypt depth and muscle thickness of each segment of small intestine of Lonchura striata were smaller than those of Copsychus saularis, and the difference of ileum muscle thickness was significant. In addition, the ileum villus height/crypt depth (VH/CD) value of Lonchura striata was significantly less than that of Copsychus saularis. The number of goblet cells in duodenum and jejunum of Lonchura striata and Copsychus saularis had no significant difference, but the number of goblet cells in ileum of Copsychus saularis was significantly larger than that of Lonchura striata. The vitality of Na+/K+-ATPase in different intestinal segments of the Lonchura striata and the Copsychus saularis was different. The vitality of Na+/K+-ATPase in the Lonchura striata was significantly higher than that of the Copsychus saularis. It can be concluded that the digestion and absorption capacity of Copsychus saularis and Lonchura striata are significantly different, and the reason may be due to their different diets and intestinal floras.

RESUMEN: En este estudio se seleccionaron seis aves Lonchura striata y seis Copsychus saularis, a las cuales se midió mediante biología cuantitativa y análisis de imágenes el índice morfológico del intestino delgado. Los cambios de las células caliciformes y Na+/K+ATPasa se detectaron mediante tinción AB- PAS y ELISA para informar los diferentes mecanismos de digestión y absorción de nutrientes entre Lonchura striata y Copsychus saularis. La altura de las vellosidades, la profundidad de las criptas y el grosor del músculo de cada segmento del intestino delgado de Lonchura striata fueron menores que los de Copsychus saularis, y se observó una diferencia significativa en el grosor de la músculatura del íleon. Además, el valor de la altura de la vellosidad del íleon/profundidad de la cripta (VH/CD) de Lonchura striata fue significativamente menor que el de Copsychus saularis. En el número de células caliciformes del duodeno y del yeyuno de Lonchura striata y Copsychus saularis no hubo una diferencia significativa, pero el número de células caliciformes en el íleon de Copsychus saularis fue significativamente mayor que el de Lonchura striata. Hubo diferencias en la vitalidad de Na+/K+-ATPasa en diferentes segmentos intestinales de Lonchura striata y Copsychus saularis. La vitalidad de Na+/K+-ATPasa en Lonchura striata fue significativamente mayor que la de Copsychus saularis. Se puede concluir que la capacidad de digestión y absorción de Copsychus saularis y Lonchura striata son significativamente diferentes, posiblemente debido a sus distintas dietas y floras intestinales.

RNA Sequencing Reveals Phenylpropanoid Biosynthesis Genes and Transcription Factors for Hevea brasiliensis Reaction Wood Formation.

Given the importance of wood in many industrial applications, much research has focused on wood formation, especially lignin biosynthesis. However, the mechanisms governing the regulation of lignin biosynthesis in the rubber tree (Hevea brasiliensis) remain to be elucidated. Here, we gained insight into the mechanisms of rubber tree lignin biosynthesis using reaction wood (wood with abnormal tissue structure induced by gravity or artificial mechanical treatment) as an experimental model. We performed transcriptome analysis of rubber tree mature xylem from tension wood (TW), opposite wood (OW), and normal wood (NW) using RNA sequencing (RNA-seq). A total of 214, 1,280, and 32 differentially expressed genes (DEGs) were identified in TW vs. NW, OW vs. NW, and TW vs. OW, respectively. GO and KEGG enrichment analysis of DEGs from different comparison groups showed that zeatin biosynthesis, plant hormone signal transduction, phenylpropanoid biosynthesis, and plant-pathogen interaction pathways may play important roles in reaction wood formation. Sixteen transcripts involved in phenylpropanoid biosynthesis and 129 transcripts encoding transcription factors (TFs) were used to construct a TF-gene regulatory network for rubber tree lignin biosynthesis. Among them, MYB, C2H2, and NAC TFs could regulate all the DEGs involved in phenylpropanoid biosynthesis. Overall, this study identified candidate genes and TFs likely involved in phenylpropanoid biosynthesis and provides novel insights into the mechanisms regulating rubber tree lignin biosynthesis.

The prevalence and risk factors for anxiety in frontline nurses under COVID-19 pandemic based on a large cross-sectional study using the propensity score-matched method

ABSTRACT Introduction: We determined the prevalence of anxiety and the associated risk factors in frontline nurses under COVID-19 pandemic. Methods: This cross-sectional study was conducted from February 20, 2020, to March 20, 2020, and involved 562 frontline nurses. The effective response rate was 87.68%. After propensity score matched, there were 532 participants left. Extensive characteristics, including demographics, dietary habits, life-related factors, work-related factors, and psychological factors were collected based on a self-reported questionnaire. Specific scales measured the levels of sleep quality, physical activity, anxiety, perceived organization support and psychological capital. Adjusted odds ratios and 95% confidence intervals were determined by binary paired logistic regression. Results: Of the nurses enrolled in the study, 33.60% had anxiety. Five independent risk factors were identified for anxiety: poor sleep quality (OR=1.235), experienced major events (OR=1.653), lower resilience and optimism of psychological capital (OR=0.906, and OR=0.909) and no visiting friend constantly (OR=0.629). Conclusions: This study revealed a considerable high prevalence of anxiety in frontline nurses during the COVID-19 outbreak, and identified five risk factors, which were poor sleep quality, experienced major events, lower resilience and optimism of psychological capital, and no visiting friend constantly. Protecting mental health of nurses is important for COVID-19 pandemic control and their wellbeing. These findings enrich the existing theoretical model of anxiety and demonstrated a critical need for additional strategies that could address the mental health in frontline nurses for policymakers.

Inhibition of B-cell receptor signaling disrupts cell adhesion in mantle cell lymphoma via RAC2.

Inhibition of the B-cell receptor (BCR) signaling pathway is highly effective in B-cell neoplasia through Bruton tyrosine kinase inhibition by ibrutinib. Ibrutinib also disrupts cell adhesion between a tumor and its microenvironment. However, it is largely unknown how BCR signaling is linked to cell adhesion. We observed that intrinsic sensitivities of mantle cell lymphoma (MCL) cell lines to ibrutinib correlated well with their cell adhesion phenotype. RNA-sequencing revealed that BCR and cell adhesion signatures were simultaneously downregulated by ibrutinib in the ibrutinib-sensitive, but not ibrutinib-resistant, cells. Among the differentially expressed genes, RAC2, part of the BCR signature and a known regulator of cell adhesion, was downregulated at both the RNA and protein levels by ibrutinib only in sensitive cells. RAC2 physically associated with B-cell linker protein (BLNK), a BCR adaptor molecule, uniquely in sensitive cells. RAC2 reduction using RNA interference and CRISPR impaired cell adhesion, whereas RAC2 overexpression reversed ibrutinib-induced cell adhesion impairment. In a xenograft mouse model, mice treated with ibrutinib exhibited slower tumor growth, with reduced RAC2 expression in tissue. Finally, RAC2 was expressed in ∼65% of human primary MCL tumors, and RAC2 suppression by ibrutinib resulted in cell adhesion impairment. These findings, made with cell lines, a xenograft model, and human primary lymphoma tumors, uncover a novel link between BCR signaling and cell adhesion. This study highlights the importance of RAC2 and cell adhesion in MCL pathogenesis and drug development.

Family Integrated Care for Preterm Infants in China: A Cluster Randomized Controlled Trial.

OBJECTIVE: To explore whether family integrated care (FICare) is feasible and improves the outcomes of preterm infants in China. STUDY DESIGN: This was a multicenter prospective cluster-randomized controlled trial comparing FICare and standard care. The primary outcome was length of stay (LOS). Secondary outcomes were nosocomial infections, duration of supplemental oxygen, breastfeeding, and weight gain. Outcomes were compared using univariate and multivariable analyses adjusted for potential confounders and clustering. RESULTS: We enrolled 601 preterm infants from 11 neonatal intensive care units (FICare, n = 298; control, n = 303). The unadjusted LOS was 30.81 vs 30.26 days (mean ratio, 1.02; 95% CI, 0.85-1.22; P = .85). After adjustment, outcomes in the FICare group were improved compared with the control group, including LOS (28.26 vs 35.04 days; mean ratio, 0.81; 95% CI, 0.72-0.91), total medical expenditures (mean ratio, 0.69; 95% CI, 0.53-0.90), weight gain velocity (15.73 vs 10.30 g/day; mean difference, 5.43; 95% CI, 3.65-7.21), duration of supplemental oxygen (13.11 vs 21.42 days; mean difference, 0.71; 95% CI, 0.50-1.00), nosocomial infection rates (4.13 vs 5.84/1000 hospital days; mean ratio, 0.67; 95% CI, 0.47-0.96), antibiotic exposure (38.63 vs 57.32/100 hospital days; mean ratio, 0.67; 95% CI, 0.47-0.96), breastfeeding rates (87.25% vs 55.78%; OR, 5.42; 95% CI, 3.25-9.05), and rehospitalization rates (3.65% vs 7.48%; OR, 0.47; 95% CI, 0.28-0.77). At follow-up to 18 months, breastfeeding rates and weight were significantly (P < .05) higher over time in the FICare group. CONCLUSIONS: FICare was feasible in Chinese neonatal intensive care units and was associated with reduced hospital LOS, medical expenditures, and rates of adverse outcomes.

The virulence of Streptococcus pneumoniae partially depends on dprA

Streptococcus pneumoniae is one of the most frequent opportunistic pathogens worldwide. DNA processing protein A (DprA) is an important factor involved in bacterial uptake and DNA integration into bacterial genome, but its role in S. pneumoniae virulence remains unclear. The aim of this study was to characterize the effects of the pneumococcal dprA gene on the pathogenesis of S. pneumoniae. To construct a dprA-deficient pneumococcal strain, the dprA gene of the S. pneumoniae strain D39 was inactivated. The virulence of this dprA-deficient strain, designated ΔD39, was compared with that of the wild-type strain by evaluating their respective capabilities to adhere to human pulmonary epithelial cells (PEC-A549) and by analyzing their choline-binding protein expression levels. In addition, the expression profiles of genes associated with virulence and host survival assays were also conducted with the mutant and the wild-type strain. Our results indicate that the capability of ΔD39 to adhere to the PEC-A549 airway cells was significantly lower (p < 0.01) compared with D39. Additionally, the 100-KD choline-binding protein was not detected in ΔD39. The addition of competence-stimulating peptide (CSP) lead to a significantly reduction of psaA mRNA expression in the dprA-deficient mutant and an increased level of psaA transcripts in the wild-type strain (p < 0.01). The median survival time of mice intraperitoneally infected with ΔD39 was significantly higher (p < 0.01) than that of mice infected with D39. The results of this study suggest that DprA has a significant effect on virulence characteristics of S. pneumoniae by influencing the expression of choline-binding protein and PsaA.(AU)

The virulence of Streptococcus pneumoniae partially depends on dprA

Abstract Streptococcus pneumoniae is one of the most frequent opportunistic pathogens worldwide. DNA processing protein A (DprA) is an important factor involved in bacterial uptake and DNA integration into bacterial genome, but its role in S. pneumoniae virulence remains unclear. The aim of this study was to characterize the effects of the pneumococcal dprA gene on the pathogenesis of S. pneumoniae. To construct a dprA-deficient pneumococcal strain, the dprA gene of the S. pneumoniae strain D39 was inactivated. The virulence of this dprA-deficient strain, designated ΔD39, was compared with that of the wild-type strain by evaluating their respective capabilities to adhere to human pulmonary epithelial cells (PEC-A549) and by analyzing their choline-binding protein expression levels. In addition, the expression profiles of genes associated with virulence and host survival assays were also conducted with the mutant and the wild-type strain. Our results indicate that the capability of ΔD39 to adhere to the PEC-A549 airway cells was significantly lower (p < 0.01) compared with D39. Additionally, the 100-KD choline-binding protein was not detected in ΔD39. The addition of competence-stimulating peptide (CSP) lead to a significantly reduction of psaA mRNA expression in the dprA-deficient mutant and an increased level of psaA transcripts in the wild-type strain (p < 0.01). The median survival time of mice intraperitoneally infected with ΔD39 was significantly higher (p < 0.01) than that of mice infected with D39. The results of this study suggest that DprA has a significant effect on virulence characteristics of S. pneumoniae by influencing the expression of choline-binding protein and PsaA.

The virulence of Streptococcus pneumoniae partially depends on dprA.

Streptococcus pneumoniae is one of the most frequent opportunistic pathogens worldwide. DNA processing protein A (DprA) is an important factor involved in bacterial uptake and DNA integration into bacterial genome, but its role in S. pneumoniae virulence remains unclear. The aim of this study was to characterize the effects of the pneumococcal dprA gene on the pathogenesis of S. pneumoniae. To construct a dprA-deficient pneumococcal strain, the dprA gene of the S. pneumoniae strain D39 was inactivated. The virulence of this dprA-deficient strain, designated ΔD39, was compared with that of the wild-type strain by evaluating their respective capabilities to adhere to human pulmonary epithelial cells (PEC-A549) and by analyzing their choline-binding protein expression levels. In addition, the expression profiles of genes associated with virulence and host survival assays were also conducted with the mutant and the wild-type strain. Our results indicate that the capability of ΔD39 to adhere to the PEC-A549 airway cells was significantly lower (p<0.01) compared with D39. Additionally, the 100-KD choline-binding protein was not detected in ΔD39. The addition of competence-stimulating peptide (CSP) lead to a significantly reduction of psaA mRNA expression in the dprA-deficient mutant and an increased level of psaA transcripts in the wild-type strain (p<0.01). The median survival time of mice intraperitoneally infected with ΔD39 was significantly higher (p<0.01) than that of mice infected with D39. The results of this study suggest that DprA has a significant effect on virulence characteristics of S. pneumoniae by influencing the expression of choline-binding protein and PsaA.

Efficient Expression and Purification of Recombinant Human Enteropeptidase Light Chain in Esherichia coli

Human enterokinase (synonym: enteropeptidase, EC 3.4.21.9) light chain (hEKL) gene was designed and artificially synthesized with built-in codon blas towards Escherichia coli codon preference. The synthetic hEKL gene was cloned into prokaryotic expression vector pMAL-s and transferred into the expression strain E. coli BL21 (DE3). Recombinant hEKL protein with a maltose binding protein (MBP) tag was expressed at high levels in soluble form, which yielded about 42% of the total cellular protein. The target protein was then purified to the homogeneity (> 95%) by affinity chromatography. The peptide substrate GST-Melittin with enterokinase recognition site was completely cleaved by the purified MBP-hEKL at the molar ratio of 1:5000 (enzyme:substrate). Tricine SDS-PAGE analysis showed that the activity of MBP-hEKL was approximately seven times that of bovine enterokinase catalytic subunit (EKMaxTM, Invitrogen). From 1 L flask culture, 206 mg pure active MBP-hEKL was with specific activity of 1.4×104 U/mg.

Epithelial sodium channel allele T594M is not associated with blood pressure or blood pressure response to amiloride.

The T594M allele of the epithelial sodium channel beta-subunit has been proposed as a gain-of-function mutation leading to salt-sensitive hypertension in blacks that is particularly responsive to the specific sodium channel antagonist amiloride. However, the positive associations derive from small convenience samples, and the amiloride challenge study lacked a control group. We determined whether the T594M allele was associated with hypertension and blood pressure (BP) response to amiloride in 2 well-characterized random population samples including 3137 Dallas County subjects and 1666 Jamaican blacks. In multivariate models, the T594M allele was not predictive of systolic BP (adjusted odds ratio for hypertension 1.1; 95% confidence interval, 0.7 to 1.8). Amiloride treatment did not lower the BP of 6 T594M heterozygotes significantly more than in 22 control subjects (P=0.8). We conclude that the T594M allele does not contribute significantly to BP in blacks and does not predict a significantly superior response to amiloride therapy.