[Research progress of phage therapy in orthopedic implant-related infection]

The widespread application of implantable materials has brought about a corresponding increase in implant-related complications, with implant-associated infections being the most critical. Biofilms, which often form on these implants, can significantly impede the effectiveness of traditional antibiotic therapies. Therefore, strategies such as surgical removal of infected implants and prolonged antibiotic treatment have been acknowledged as effective measures to eradicate these infections. However,the challenges of antibiotic resistance and biofilm persistence often result in recurrent or hard-to-control infections, posing severe health threats to patients. Recent studies suggest that phages, a type of virus, can directly eliminate pathogenic bacteria and degrade biofilms. Furthermore, clinical trials have demonstrated promising therapeutic results with the combined use of phages and antibiotics. Consequently, this innovative therapy holds significant potential as an effective solution for managing implant-associated infections. This paper rigorously investigates and evaluates the potential value of phage therapy in addressing orthopedic implant-associated infections, based on a comprehensive review of relevant scientific literature.

Impact of shift work on dementia: a systematic review and dose-response meta-analysis

OBJECTIVES

Although shift work has been reported as having a link to dementia, evidence remains inconsistent, and a comprehensive dose-response meta-analysis of the association is still lacking. We therefore conducted this meta-analysis to explore the association between shift work and the risk of dementia.

STUDY DESIGN

Systematic review and dose-response meta-analysis.

METHODS

PubMed, Embase, and Web of Science databases were systematically searched. Fixed or random-effects models were used to estimate the summary relative risks (RRs) and 95% confidence intervals (95% CIs). Generalized least squares regression was used to estimate dose-response associations, and restricted cubic splines were used to examine possible linear or non-linear associations.

RESULTS

Five articles (10 studies) with 72,999 participants and 23,067 cases were eventually included in the meta-analysis. The summary RRs and 95% CIs of dementia risk with shift work and night shift work versus daytime work were 1.13 (95% CI: 1.05-1.21, I2 = 46.70%) and 1.13 (95% CI: 1.03-1.24, I2 = 9.20%), respectively. The risk of dementia increased by 1% (RR = 1.01, 95% CI: 1.01-1.02, I2 = 41.3%) with each 1-year increase in the duration of shift work. We found a non-linear dose-response association between the duration of shift work and the risk of dementia (Pnon-linearity = 0.006). Though the shape of the curve was steeper with the duration of shift work <7 years, the increase was more gradual after 7 years.

CONCLUSION

Our findings suggest that shift work may be a risk factor for future dementia and that controlling the length of shift work is a feasible measure that may contribute to prevent dementia.

Epidemiological analysis of septic shock in the plateau region of China

Purpose

Little epidemiological data exist on patients with severe infection in the plateau region of China, and the data that do exist are lacking in quality. Using the medical records of patients with severe infection in the Department of Intensive Medicine (intensive care unit; ICU) of the People's Hospital of Tibet Autonomous Region, this study analyzed the epidemiological and clinical characteristics of patients with septic shock in plateau area (Tibet), with the ultimate aim of reducing the incidence and mortality from this condition.

Methods

Clinical data on 137 patients with septic shock in the studied ICU from November 2017 to October 2019 were retrospectively analyzed using SPSS, Version 21.0.

Results

Among the 137 patients with septic shock, there were 47 survivors and 90 in-hospital or post-discharge deaths. There were 91 male patients and 46 female patients. The incidence of septic shock was 11.3%, and mortality rate was 65.7%. Median age was 55 years old, median APACHE-II score on the day of admission was 17, median SOFA score was 11, and median number of organ injuries was one. APACHE-II score (P = 0.02), SOFA score (P &lt; 0.001), and the number of organ injuries (P &lt; 0.001) were higher among patients who died than among survivors. The infections were mainly pulmonary and abdominal, and the main pathogen was gram-negative bacteria.

Conclusion

The incidence and mortality of septic shock in ICU wards in Tibet are very high. The APACHE-II score, SOFA score, and the number of organ damage on the first day after diagnosis are independent risk factors for septic shock. To some extent, this study reflects the epidemiological characteristics of septic shock in the plateau region of China (≥ 3,650 m above sea level) and provides data that can support the prevention and treatment of sepsis in the future. More and deeper epidemiological studies of septic shock are necessary.

[Characteristics of the immune microenvironment and related treatment strategies in patients with periprosthetic joint infection]

Periprosthetic joint infection (PJI) involves complex immunomodulatory interactions between pathogens,biomaterials,and hosts,and correlates with alterations in the ratio of immune cells as well as in the concentration of immune checkpoint molecules.Prosthesis,biofilm,microorganisms,and host constitute a special and complex immune microenvironment.Fully studying the characteristics of immune microenvironment and potential targets of immunotherapy in orthopedic implant-associated infections are expected to provide a new direction for clinical treatment of PJI. An overview of the literature related to PJI and immune regulation at domestic and international sites was conducted to summarize and analyze the characteristics of the immune microenvironment and the potential value of related immunotherapy, aiming to provide new insights for the targeted treatment of PJI.

Vimentin regulation of autophagy activation in lung fibroblasts in response to lipopolysaccharide exposure in vitro

Background

The activation and assembly of the NLRP3 inflammasome is dependent on the interaction between NLRP3 and the intermediate filament protein vimentin in an acute respiratory distress syndrome (ARDS) model. We investigated the role of vimentin in this process using human fetal lung (HFL-1) fibroblasts with vimentin transfer genes or gene knockdown and lipopolysaccharide (LPS) intervention.

Methods

HFL-1 cells [con-vector + LPS, vimentin-pCMV3 (VIM-pCMV3), con-siRNA, and vimentin siRNA (VIM-siRNA)] were treated with LPS. An oxidative stress damage assessment, apoptosis analysis, and quantification of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, and IL-10 by enzyme linked immunosorbent assay (ELISA) were performed. Immunoblotting was used to reveal the autophagy pathway.

Results

We demonstrated that in response to LPS vimentin expression was lower in the HFL-1 cells with the vimentin gene knocked down. Specifically, an increase in oxidative stress, a decrease in mitochondrial membrane potential, or an increase in calcium ion permeability resulted in an increase in the fibroblast apoptosis rate. In addition, the inflammatory response after vimentin gene knockout was upregulated, as indicated by higher levels of TNF-a, IL-1β, IL-6, and IL-10. Importantly, the mechanism of suppression of vimentin in the lung fibroblasts was caused by a decrease in autophagy, an increase in mitochondrial membrane protein, and a decrease in mitochondrial function, which may contribute to the augmented cellular injury generated during the response to LPS.

Conclusions

This study provides insights into whether vimentin may interfere with the inflammatory cascade by activating the autophagy pathway of mitochondrial lung fibroblasts in the early stage of acute lung injury (ALI).

Negative central venous to arterial lactate gradient in patients receiving vasopressors is associated with higher ICU 30-day mortality: a retrospective cohort study

Background

Serum lactate has long been used to evaluate hypoxia and predict prognosis in critically ill patients, however, discrepancy in lactate measurements between different sites have not been recognized as a useful tool for monitoring hypoxia and evaluating outcome.

Methods

Data were obtained from the clinical information system of the intensive care unit (ICU) in a tertiary academic hospital for 1582 ICU patients with vasoactive drug requirement and valid paired blood gas. The mortality rates were compared between patients with sustained negative venous to arterial lactate gradient (VALac) and the others using the Cox proportional hazard model. Predictive factors associated with negative VALac were searched.

Results

A sustained negative VALac was significantly associated with higher 30 day ICU mortality [Adjusted hazard ratio (HR) = 2.31, 95% confidence interval (CI), 1.07–4.99; p = 0.032. Propensity score- weighted HR: 2.57; 95% CI, 1.17–5.64; p = 0.010]. Arterial lactate in the first blood gas pair, 24-h arterial lactate clearance, use of epinephrine, mean positive end-expiratory pressure level, and extracorporeal membrane oxygenation initiation showed statistically significant association with sustained negative VALac during the first 24 h.

Conclusion

The sustained negative VALac in the early stage of treatment may suggest additional information about tissue hypoxia than arterial lactate alone. Critical care physicians should pay more attention to the lactate discrepancy between different sites in their clinical practice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-021-01237-5.

Epidemiology, mortality and risk factors for patients with K. pneumoniae bloodstream infections: Clinical impact of carbapenem resistance in a tertiary university teaching hospital of Beijing

BACKGROUND

This study compared the epidemiology of carbapenem-resistant (CRKP) and carbapenem-sensitive (CSKP) K. pneumoniae bloodstream infections (BSIs), and assessed risk factors for 28-day mortality of patients with K. pneumoniae BSIs.

METHODS

A retrospective cohort study was conducted in a 2000-bed tertiary teaching hospital of Beijing between Jan 1st 2013 to Dec 31st, 2019. All patients with K. pneumoniae BSI were identified through the Hospital Information System. The endpoints included incidence rate, mortality and risk factors for mortality of patients with K. pneumoniae BSIs.

RESULTS

496 patients with K. pneumoniae BSIs were included in the analysis, with 108 CRKP BSIs. The incidence rate of K. pneumoniae BSI was 10.6 (CI: 9.7, 11.6) per 100 000 patient-days, with the rate for CRKP BSI was 2.3 (95% CI: 1.9, 2.8). The 28-day mortality was 38.0% for CRKP BSI and 8.8% for CSKP BSI, respectively. Logistic analysis showed, higher Charlson Comorbidity Index score (OR = 1.26, 95%CI 1.12-1.43, p < 0.001), respiratory failure (OR = 2.73, 95%CI1.28-5.84, p = 0.010), renal failure (OR = 4.13, 95%CI1.93-8.83, p < 0.001), septic shock (OR = 8.77, 95%CI3.60-21.32, p < 0.001), mechanical ventilation (OR = 4.41, 95%CI1.59-12.25, p = 0.004) and CRKP infection (OR = 3.04, 95%CI1.28-7.22, p = 0.012) were independently associated with 28-day mortality.

CONCLUSIONS

Considerable incidence rate and remarkable mortality of patients with K. pneumoniae (especially CRKP) BSI was declared in the study. Patient conditions before (higher CCI) and after presentation (respiratory failure, renal failure, septic shock), and healthcare factors (mechanical ventilation and CRKP infection) were independently associated with 28-day mortality. Understanding these risks helps better establishment of infection control strategies.

MicroRNA-142 promotes the development of nasopharyngeal carcinoma through targeting PTEN

OBJECTIVE

To elucidate whether microRNA-142 could regulate the development of nasopharyngeal carcinoma (NPC) by mediating gene of phosphate and tension homology deleted on chromosome ten (PTEN) expression.

PATIENTS AND METHODS

The microRNA-142 expression in NPC tissues and paracancerous tissues was detected by the quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Correlation between the microRNA-142 expression and the prognosis of NPC patients was analyzed. MicroRNA-142 expression in NPC cell lines was determined as well. By transfection of microRNA-142 inhibitor or negative control, biological performances of NPC cells were accessed through cell counting kit-8 (CCK-8), colony formation, wound healing, and transwell assay. Dual-luciferase reporter gene assay was conducted to verify the binding condition between microRNA-142 and its target gene PTEN. Rescue experiments were carried out by co-transfection of microRNA-142 inhibitor and si-PTEN, followed by detecting the invasive capacity of NPC cells. Protein expressions of relative genes in the PI3K/AKT pathway after the microRNA-142 knockdown in NPC cells were determined by Western blot.

RESULTS

MicroRNA-142 was highly expressed in NPC tissues than that of paracancerous tissues, which was correlated with poor prognosis of NPC patients. MicroRNA-142 was also highly expressed in NPC cells. Downregulated microRNA-142 inhibited proliferative, migratory, and invasive capacities of NPC cells. Dual-luciferase reporter gene assay verified that microRNA-142 could directly bind to PTEN. Knockdown of PTEN could reverse the inhibitory effect of microRNA-142 on invasive capacity of NPC cells. Finally, Western blot results demonstrated that the microRNA-142 knockdown inhibited the PI3K/AKT pathway in NPC cells.

CONCLUSIONS

MicroRNA-142 is highly expressed in NPC. MicroRNA-142 enhances the proliferative and invasive capacities of NPC cells by inhibiting PTEN expression, thus promoting NPC development.

Management of gynecology patients during the coronavirus disease 2019 pandemic: Chinese expert consensus

Since December 2019, the outbreak of novel coronavirus disease 2019 became a major epidemic threat in China and later spread worldwide. During the coronavirus disease 2019 outbreak in mainland China, the Chinese Obstetricians and Gynecologists Association distributed guidelines regarding the care of gynecologic patients. These guidelines were developed by the Department of Obstetrics and Gynecology at the Peking Union Medical College Hospital and represent an effort to integrate infection control strategy and promote professionalism in medical practice. The guidelines represent collaboration with experts from 31 provinces and autonomous regions of mainland China over 2 weeks’ time. With the implementation of these guidelines, no nosocomial infections of coronavirus disease 2019 have been identified at the Peking Union Medical College Hospital. We think these guidelines might be helpful to departments of obstetrics and gynecology internationally during these unprecedented times. In our guidelines, we describe basic infection precaution principles, an epidemiologic screening tool, prioritization of surgical procedures, and operating room requirements. Using these principles, we then review the management of gynecologic patients during the coronavirus disease 2019 epidemic in the outpatient and operative and nonoperative inpatient settings and in clinical trials.

Clinical Performance Evaluation of VersaTrek 528 Blood Culture System in a Chinese Tertiary Hospital

Background: The aim of this study was to evaluate the clinical performance of VersaTrek 528 compared to BACTEC FX 400 blood culture (BC) systems.

Materials and Methods: Simulated and clinically obtained BCs were used in the study. Confirmed bacterial species (n = 78), including 43 Gram-positives, 30 Gram-negatives, and 5 Candida albicans strains, were each inoculated into BC bottles. Clinically obtained BCs were subdivided into two groups, A and B. In group A were 72 BC sets (pair: aerobic and anaerobic) in which a set inoculated with 5 ml blood was processed in the VersaTrek BC system, whilst the one inoculated with 10 ml blood was processed in the FX BC system. In group B, 76 BC sets (pairs) corresponding to 152 VersaTrek bottles and 152 FX bottles were inoculated with the same volume (10 ml) of blood, and processed in each system.

Results: In the simulated BC study, 90% (63/70) of the VersaTrek aerobic bottles were positive, which was higher than that of FX 400 (59/70, 84%), but was not statistically significant (P = 0.423). In contrast, FX 400 anaerobic bottles had a higher positive rate than the other BC system (84 vs. 77%), although it was statistically insignificant (P = 0.267). Time to detection of organisms in the two BCs was comparable for both aerobic (P = 0.131) and anaerobic bottles (P = 0.104). In clinical BCs of group A, FX BC system had slightly higher positive rates for both aerobic (11.1 vs. 9.7%, P = 0.312) and anaerobic (8.3 vs. 6.9%, P = 0.375) bottles. However, the difference was not statistically significant. In group B, VersaTrek aerobic bottles had a higher positive rate compared to the other BC system (10.5 vs. 5.2%, P = 0.063). In terms of positive rates of sub-studies A and B, VersaTrek and FX BC systems were comparable.

Conclusion: There was no significant difference between the two BC systems in the detection of bacteria and fungi in simulated BCs. In clinical BCs, the performance of the VersaTrek BC system, with inoculation of 5 or 10 ml patient’s blood, was comparable to the FX system with inoculation of 10 ml patient’s blood.

[The relationship between incidence of secretory otitis media and passive smoking in children]

Children with secretory otitis media are often the result of multiple factors. Recent epidemiological studies on its incidence have mentioned the effects of passive smoking on its incidence. This article explores the potential links between the two by summarizing relevant literatures.

Use of stepwise lactate kinetics-oriented hemodynamic therapy could improve the clinical outcomes of patients with sepsis-associated hyperlactatemia

Background

Setting lactate kinetics at >30% might improve the clinical outcomes of patients with sepsis-associated hyperlactatemia. The aim of this study was to explore the outcome benefits of stepwise lactate kinetics vs central venous oxygen saturation (ScvO₂)-oriented hemodynamic therapy at 6 h as the protocol goal during early resuscitation.

Methods

The relevant parameters and adverse events after different targets in 360 randomly assigned patients with sepsis-associated hyperlactatemia were recorded and compared.

Results

Heart rate (HR) at 48 h in the ScvO₂ group was higher than in the lactate kinetics group (105 ± 19 bpm vs 99 ± 20 bpm, P = 0.040). The liquid balance at 4 h, 12 h, and 24 h in the lactate kinetics group was larger than in the ScvO₂ group (1535 (1271–1778) ml vs 826 (631–1219) ml, P < 0.001; 1688 (1173–1923) ml vs 1277 (962 − 1588) ml, P <0.001; and 1510 (904–2087) ml vs 1236 (740–1808) ml, P = 0.005), respectively. Mortality was higher in the ScvO₂ group (27.9% vs 18.3%, P = 0.033), but there was no significant difference between the two groups in the length of stay in the ICU or mechanical ventilation. In terms of new onset organ dysfunction, there was a significant difference between the two groups in total bilirubin at 48 h and 72 h. Based on the 60-day survival curves, there was significantly more mortality in the ScvO₂ group than in the lactate kinetics group (X² = 4.133, P = 0.042). In addition, fewer adverse events occurred in the lactate kinetics group.

Conclusions

Stepwise lactate kinetics-oriented hemodynamic therapy can reduce mortality in patients with sepsis-associated hyperlactatemia compared with ScvO₂-oriented therapy.

Trial registration

National Institutes of Health Clinical Trials Registry, NCT02566460. Registered on 26 September 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1617-1) contains supplementary material, which is available to authorized users.

Silencing of microRNA-138-5p promotes IL-1β-induced cartilage degradation in human chondrocytes by targeting FOXC1: miR-138 promotes cartilage degradation

Objectives

Osteoarthritis (OA) is characterised by articular cartilage degradation. MicroRNAs (miRNAs) have been identified in the development of OA. The purpose of our study was to explore the functional role and underlying mechanism of miR-138-5p in interleukin-1 beta (IL-1β)-induced extracellular matrix (ECM) degradation of OA cartilage.

Materials and Methods

Human articular cartilage was obtained from patients with and without OA, and chondrocytes were isolated and stimulated by IL-1β. The expression levels of miR-138-5p in cartilage and chondrocytes were both determined. After transfection with miR-138-5p mimics, allele-specific oligonucleotide (ASO)-miR-138-5p, or their negative controls, the messenger RNA (mRNA) levels of aggrecan (ACAN), collagen type II and alpha 1 (COL2A1), the protein levels of glycosaminoglycans (GAGs), and both the mRNA and protein levels of matrix metalloproteinase (MMP)-13 were evaluated. Luciferase reporter assay, quantitative real-time polymerase chain reaction (qRT-PCR), and Western blot were performed to explore whether Forkhead Box C1 (FOCX1) was a target of miR-138-5p. Further, we co-transfected OA chondrocytes with miR-138-5p mimics and pcDNA3.1 (+)-FOXC1 and then stimulated with IL-1β to determine whether miR-138-5p-mediated IL-1β-induced cartilage matrix degradation resulted from targeting FOXC1.

Results

MiR-138-5p was significantly increased in OA cartilage and in chondrocytes in response to IL-1β-stimulation. Overexpression of miR-138-5p significantly increased the IL-1β-induced downregulation of COL2A1, ACAN, and GAGs, and increased the IL-1β-induced over expression of MMP-13.We found that FOXC1 is directly regulated by miR-138-5p. Additionally, co-transfection with miR-138-5p mimics and pcDNA3.1 (+)-FOXC1 resulted in higher levels of COL2A1, ACAN, and GAGs, but lower levels of MMP-13.

Conclusion

miR-138-5p promotes IL-1β-induced cartilage degradation in human chondrocytes, possibly by targeting FOXC1.

Cite this article: Y. Yuan, G. Q. Zhang, W. Chai,M. Ni, C. Xu, J. Y. Chen. Silencing of microRNA-138-5p promotes IL-1β-induced cartilage degradation in human chondrocytes by targeting FOXC1: miR-138 promotes cartilage degradation. Bone Joint Res 2016;5:523–530. DOI: 10.1302/2046-3758.510.BJR-2016-0074.R2.

[Analysis of association of human 8-oxoguanine giycosylase 1 polymorphism with the susceptibility of laryngeal cancer]

Objective: To study the association between human 8-oxoguanine giycosylase 1 (hOGG1) gene polymorphisms and the risk of laryngeal carcinoma. Methods: A total of 86 patients with laryngeal carcinoma treated in The Air Force General Hospital and the Bozhou People's Hospital of Anhui Province from Jan 2010 to Dec 2014 were included in experimental group, and 86 healthy adults were selected as control group. The hOGG1 gene polymorphisms of subjects in two group were detected with by polymerase chain reaction amplification and gene sequencing technology, the differences in hOGG1 gene polymorphisms between two groups were analyzed. Results: The frequencies of hOGG1 gene heterozygous type (Ser/Cys) and mutant type (Cys/Cys) in experimental group were higher than those in control group(P<0.05). Compared to individuals with hOGG1 gene Ser/Ser, individuals with hOGG1 gene Ser/Cys had a 2.97-fold increased risk of laryngeal carcinoma, and individuals with hOGG1 gene Cys/Cys had a 8.09-fold increased risk of laryngeal carcinoma. Stratified by smoking or not, it was found that the proportion of heterozygous type or mutant type in smokers was higher significantly than non-smokers (P<0.05). Conclusion: Individuals with hOGG1 gene heterozygous type (Ser/Cys) or mutant type (Cys/Cys) have a higher risk of laryngeal carcinoma, with interaction between these gene types and smoking, and the gene types could be used as predictors for the occurrence of laryngeal carcinoma.

[The influence on the peeling off time of the tunica albuginea after 4-8℃ cool water was applied to children's low temperature plasma-assisted tonsillectomy]

Objective:The aim of this study is to discuss the influence on the peeling off time of the tunica albuginea after 4-8℃ cool water was applied to children 's low temperature plasmaassisted tonsillectomy.Method:One hundred and seventeen benign hypertrophy of tonsil patients were recruited,the 56 cases of them were served as experimental group,who were treated with plasma tonsillectomy using 4-8℃ normal saline as medium,while the 61 cases were served as control group,who were treated with plasma tonsillectomy using 22-25℃ normal saline as medium.Then,we analyzed the peeling off time of the tunica albuginea between experimental and control group.Result:The difference of formation time between experimental group and control group was not statistically significant(P >0.05).The average peeling off time of the tunica albuginea was (11.32±2.51) days in experimental group,while time was(15.03±4.12) days in control group.There was a statistical difference between them.Conclusion:The use of 4-8℃ cold water in children's low temperature plasma-assisted tonsillectomy can reduce the peeling off time of the tunica albuginea,and it indicate that the ice water medium can reduce the heat injury caused by the plasma operation.

[The diagnosis and treatment progress of vocal fold leukoplakia]

Vocal fold leukoplakia is a descriptive diagnosis, and can be divided into simple hyperplasia, precancerous lesions(with atypical hyperplasia) and invasive carcinoma according to pathological types. Because of a close relationship with the laryngeal carcinoma, knowing the risk factors and treatment methods of vocal fold leukoplakia has grate significance in preventing the malignant change and recurrence. This paper summarizes the recent progress in clinical diagnosis and treatment of vocal cord leukoplakia, mainly including risk factors, means of examination, treatment and prognosis.

Role of sTREM-1 in predicting mortality of infection: a systematic review and meta-analysis

OBJECTIVES

Several studies have investigated the prognostic value of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) in patients with infection. However, the result was controversial. Thus, the purpose of the present meta-analysis was to determine the prognostic value of the sTREM-1 level in predicting mortality at the initial stage of infection.

METHODS

The literature was searched in the PubMed, EMBASE, Web of Knowledge and Cochrane databases. A 2×2 contingency table was constructed on the basis of mortality and sTREM-1 levels in patients with infection. 2 authors independently judged study eligibility and extracted data. The prognostic value of sTREM-1 in predicting mortality was determined using a bivariate meta-analysis model. Q-test and I(2) index were used to test heterogeneity.

RESULTS

9 studies were selected from 803 studies. An elevated sTREM-1 level was associated with a higher risk of death in infection, with pooled risk ratio (RR) was 2.54 (95% CI 1.77 to 3.65) using a random-effects model (I(2)=53.8%). With the bivariate random-effects regression model, the pooled sensitivity and specificity of sTREM-1 to predict mortality in infection were 0.75 (95% CI 0.61 to 0.86) and 0.66 (95% CI 0.54 to 0.75), respectively. The diagnostic OR was 6 (95% CI 3 to 10). The overall area under the summary receiver operator characteristic (SROC) curve was 0.76 (95% CI 0.72 to 0.79). When we calculated the sepsis subgroup, the pooled RR was 2.98 (95% CI 2.19 to 4.40). The pooled sensitivity and specificity were 0.74 (95% CI 0.58 to 0.85) and 0.72 (95% CI 0.62 to 0.80), respectively. The overall area under the SROC curve was 0.78 (95% CI 0.74 to 0.81).

CONCLUSIONS

Elevated sTREM-1 concentrations had a moderate prognostic significance in assessing the mortality of infection in adult patients. However, sTREM-1 alone is insufficient to predict mortality as a biomarker.

Prognostic value of extravascular lung water and its potential role in guiding fluid therapy in septic shock after initial resuscitation

PURPOSES

To explore whether extravascular lung water (EVLW) provides a valuable prognostic tool guiding fluid therapy in septic shock patients after initial resuscitation.

MATERIALS AND METHODS

We performed a retrospective study of septic shock patients who achieved adequate initial fluid resuscitation with extended hemodynamic monitoring, analyzing the prognostic value of EVLW and whether fluid therapy for 24 (T24) or 24-48 hours (T24-48) after initial resuscitation with a recommended value of EVLW yielded a 28-day mortality advantage.

RESULTS

One hundred five patients with septic shock were included in this study, 60 (57.1%) of whom died after 28 days. For 48 hours after initial resuscitation, the daily fluid balance (DFB; T24: 2494 ± 1091 vs 1965 ± 964 mL [P = .011] and T24-48: 2127 ± 783 vs 1588 ± 665 mL [P < .001]) and daily maximum values of the EVLW index (EVLWImax; T24: 13.9 ± 3.7 vs 11.5 ± 3.2 mL/kg [P < .001] and T24-48: 14.4 ± 5.3 vs 12.0 ± 4.4 mL/kg [P < .001]) were significantly higher in nonsurvivors than in survivors. In multivariate regression analysis, the DFB (T24: odds ratio [OR] 1.001 [P = .016] and T24-48: OR 1.001 [P = .008]), EVLWImax (T24: OR 2.158 [P = .002] and T24-48: OR 3.277 [P = .001]), blood lactate (T24: OR 1.368 [P = .021] and T24-48: OR 4.112 [P < .001]), and central venous blood oxygen saturation (T24: OR 0.893 [P = .013] and T24-48: OR 0.780 [P = .004]) were all independently associated with the 28-day mortality. A receiver operating characteristic analysis revealed that area under the curve values of 0.82 (95% confidence interval, 0.74-0.91; P < .001) and 0.90 (95% confidence interval, 0.83-0.96; P < .001) for EVLWImax ≥ 12.5 mL/kg (T24 and T24-48) predicted a 28-day mortality with sensitivities of 88% (80%-96%) and 95% (90%-100%) and specificities of 60% (46%-74%) and 76% (63%-89%).The EVLWImax was correlated with DFB with Spearman ρ values of 0.497 (T24: P < .001) and 0.650 (T24-48: P < .001). Cox survival and regression analyses demonstrated that EVLWImax ≥ 12.5 mL/kg (T24 and T24-48) was associated with higher risk and increased mortality, with adjusted ORs of 4.77 (P < .001) and 10.86 (P < .001).

CONCLUSIONS

A higher EVLW in septic shock patients after initial resuscitation was associated with a more positive fluid balance and increased mortality, which is an independent predictor of the 28-day mortality in septic shock patients after initial resuscitation.

[Occurrence and outcome of left ventricular-arterial coupling in sepsis-induced cardiomyopathy]

OBJECTIVE

To explore the occurrence and development of sepsis-induced cardiomyopathy (SIC) and its correlation with left ventricular arterial coupling.

METHODS

A total of 46 SIC patients were recruited and divided into non-survival and survival groups. And hemodynamics parameters, lactate, cardiac elastance (Ees), arterial elastance (Ea) and ventricular-arterial coupling (Ea/Ees), stroke work (SW), total mechanical work (PVA) and cardiac work efficiency (SW/PVA) were recorded before and after an onset of SIC.

RESULTS

The occurrence and development of SIC had close correlations with left ventricular arterial coupling.Heart and arterial elastance affected the occurrence and outcome of SIC. The former was a underlying cause while the latter a precipitating factor; the primary treatment goal of SIC was improving ventricular-arterial coupling. And the short-term objective was reducing arterial elastance and long-term strategy improving cardiac elastance; Ea declined initially when SIC recovered. And it was consistent with ventricular-arterial coupling improvement. Ees recovery was delayed; before and after SIC, low peripheral vascular resistance within 36 h could reduce arterial elastance Ea; ventricular artery coupling affected cardiac external work, work efficiency and stroke volume and was associated with tissue perfusion.

CONCLUSION

The occurrence and outcome of SIC are simultaneously influenced by Ees and Ea and are closely correlated with Ea/Ees. Treatment goal of SIC is improving ventricular-arterial coupling.Ea should be reduced within 36 h and Ees should be boosted after 48 h.

[The application of combined central venous pressure and oxygen metabolism parameters monitoring in diagnosing septic shock-induced left ventricular dysfunction]

OBJECTIVE

To evaluate the value of central venous pressure (CVP), central venous oxygen saturation (ScvO₂) and venous-arterial carbon dioxide partial pressure gradient (Pv-aCO₂)) in the diagnosis of septic shock-induced left ventricular dysfunction.

METHODS

Consecutive patients with septic shock were enrolled from September 2013 to September 2014 in ICU at Peking Union Medical College Hospital. The data of CVP, Pv-aCO₂) and ScvO₂) were recorded and analyzed. According to the left ventricular ejection fraction (LVEF) tested by bedside echocardiography, the patients were divided into two groups: new onset of left ventricular dysfunction (LVEF < 50%) group and non-left ventricular dysfunction (LVEF ≥ 50%) group. A diagnostic model was created by logistic regression. The diagnostic performance and cut-off values of CVP, Pv-aCO₂, ScvO₂) were determined using receiver operating characteristic (ROC) curve analysis.

RESULTS

Among 93 patients enrolled, 39 were diagnosed with left ventricular dysfunction. In the new onset group, CVP [(12.5 ± 3.9) mmHg (1 mmHg = 0.133 kPa) vs (10.4 ± 2.5) mmHg; P = 0.005] and Pv-aCO₂[(7.5 ± 3.9) mmHg vs (4.5 ± 2.6) mmHg; P < 0.001] were significantly higher than those in the non-left ventricular dysfunction group, while Scv2 [(62.4 ± 10.5)% vs (72.6 ± 9.0)%; P < 0.001] was significantly lower. As far as the diagnostic value of these three parameters were concerned for left ventricular dysfunction, the sensitivity of CVP ≥ 12.5 mmHg was 46.2%, specificity 81.5% with an area under ROC curve (AUCROC) 0.674; the sensitivity of Pv-aCO₂≥ 5.0 mmHg 76.9%, specificity 37.0%, AUCROC 0.738; the sensitivity of ScvO₂≤ 65.8% 64.1%, specificity 78.6%, AUCROC 0.775. When the cut-off values were determined by ROC, the diagnostic performance of the model was ≥ 0.377 with the sensitivity, specificity and AUCROC 82.1%, 79.6% and 0.835, respectively.

CONCLUSION

In patients with septic shock, the logistic regression model established by CVP, Pv-aCO₂and ScvO₂contributes to the diagnosis of septic shock-induced left ventricular dysfunction.

[A pilot study of measuring inferior vena cava internal diameter on transverse section plane in different sites by ultrasonography]

OBJECTIVE

To investigate the shape change index (SCI) of inferior vena cava (IVC) measured from subcostal area and right mid-axillary line through ultrasonography laying the foundation for future research about SCI and volume status.

METHODS

A total of 107 patients were enrolled in the Critical Care Medicine Department of Peking Union Medical College Hospital from December, 2014-January, 2015. The maximal diameter (MXD) and the minimal diameter (MID) were measured transversely from subcostal area and right mid-axillary line. The SCI was calculated.

RESULTS

Totally 47 patients (42 with spontaneous breathing and 5 on mechanical ventilation) achieved measurements on transversal plane from subcostal area and right mid-axillary line. (1) The internal diameter of IVC on longitudinal plane measured from subcostal area was statistically different from that measured from right mid-axillary line both at end inspiration (P=0.001) and at end expiration (P=0.027). (2) No difference were found in the SCI measured from subcostal and right mid-axillary line both at end inspiration and at expiration. (3) The internal diameter of IVC and the SCI measured on transversal plane from subcostal area correlated well with that measured from mid-axillary line both at end inspiration (SCI:r=0.866, P=0.000) and at end expiration (SCI: r=0.887, P=0.000).

CONCLUSIONS

Inferior vena cava internal diameters and the shape change index measured through ultrasonography on transversal planefrom subcostal area are correlated well with those from mid-axillary line. Measurements from the two sites can be replacedby each other.

Using critical care chest ultrasonic examination in emergency consultation: a pilot study

The purpose of this study was to investigate the effects of critical care chest ultrasonic examination (CCUE) by intensivist on the diagnosis and treatment decisions in emergent consultation for patients who may have a problem-need transfer to an intensive care unit (ICU). A total of 130 patients who required emergent consultation in the ordinary wards were included in this study. Patients were randomly divided into conventional group (n = 63) and CCUE group (n = 67, added CCUE). The two groups showed no significant differences in general clinical information or final diagnosis (p > 0.05). The CCUE group had a shorter time to preliminary diagnosis, final diagnosis, treatment response and X-ray/computed tomography examination; a delay in ICU transfer and ICU stay days (3.9 ± 1.2 vs. 5.4 ± 1.9 d, p < 0.05) and a higher diagnostic accuracy than the conventional group (p < 0.001). In conclusion, CCUE could help early diagnosis and therapy for the patient who may need to transfer to the ICU and reduce the ICU stay for in-hospital patients in emergent consultation.

[The effects of Peking Union Medical College Hospital Critical Ultrasonic Management scheme on the etiological diagnosis of dyspnea and/or hemodynamic instability in ICU patients]

OBJECTIVE

To investigate the effects of Peking Union Medical College Hospital (PUMCH) Critical Ultrasonic Management (PCUM) scheme on the etiological diagnosis and treatment decisions for the patients with dyspnea and/or hemodynamic instability in ICU.

METHODS

Patients who suffered from dyspnea and/or hemodynamic instability in PUMCH ICU were included in this study. The time to preliminary diagnosis, time to final diagnosis, diagnostic accuracy, time to accurate treatment, time to consultation with other specialties, time to other examinations were recorded.

RESULTS

A total of 129 patients were included in this study. In patients applied with PCUM scheme, time to preliminary diagnosis, final diagnosis and accurate treatment were (15 ± 6)min, (65 ± 16)min and (34 ± 14)min respectively, and the accuracy of diagnosis was 93.0%. PCUM patients had high sensitivity and specificity for the diagnosis of acute respiratory distress syndrome (ARDS)(sensitivity 90.2%/specificity 93.6%), distributive shock(sensitivity 92.5%/specificity 93.6%) and pulmonary edema(sensitivity 93.4%/specificity 92.7%) etc.

CONCLUSIONS

The PCUM scheme is associated with short time to preliminary diagnosis and high diagnostic accuracy and could improve the treatment for patients with dyspnea and/or hemodynamic instability.

[Prognostic outcomes of adherence to guideline of bundle therapy by key points of control strategies in septic shock patients]

OBJECTIVE

To evaluate the improvement of clinical septic shock guideline of bundle therapy by key points of control strategies and its impact on the outcomes of septic shock patients.

METHODS

The quality control team and sepsis steering committee were established to apply key points of control strategies to improve the clinical septic shock guideline of bundle therapy. The time to resuscitation, antibiotics and cultures, the implementation rate of 6-hour resuscitation goals, glucose control and lung protective ventilation strategies were recorded during the plan-do-check-act (PDCA) steps. And the changes of length of ICU stay and hospital mortality were analyzed.

RESULTS

Between July 2009 and December 2012, a total of 563 sequential septic shock patients were admitted. Demographics included median age, gender ratio, initial Acute Physiology and Chronic Health Evaluation II (Apache II) score and sources of infection showed no significant differences during this period. Compared with 2009, the time to resuscitation (65.1 ± 10.3 vs 99.7 ± 10.5 min, P < 0.01) , the time to cultures (55.9 ± 5.2 vs 71.5 ± 7.9 min, P < 0.01) and the time to antibiotics (58.1 ± 5.8 vs 152.8 ± 16.1 min, P < 0.01) significantly decreased in 2012. The implementation rate of 6-hour resuscitation goals (68.7% vs 28.7%, P < 0.01) , the implementation rate of glucose control (79.6% vs 40.0%, P < 0.01) and the implementation rate of lung protective ventilation strategies (74.1% vs 51.4%, P = 0.004) improved significantly form 2009 to 2012. The length of ICU stay (7.2 ± 1.5 vs 9.8 ± 2.7 d, P < 0.01) decreased. And hospital mortality decreased from 40.0% in 2009 to 23.1% in 2012 (P = 0.015).

CONCLUSION

The key points of control strategies can improve the clinical septic shock guideline of bundle therapy performance so that there are significant decreases of length of ICU stay and hospital mortality of septic shock patients.

[The effect of body temperature control on organ function and prognosis in patients with refractory septic shock]

OBJECTIVE

To investigate the effect of body temperature control on organ function and prognosis in patients with refractory septic shock.

METHODS

A total of 67 eligible patients with the body temperature over 38.5 °C were enrolled in the study and all patients were treated with a water-flow cooling blanket to control the body temperature below 38.3 °C for 72 hours. The core and peripheral temperature was tested at 1 hour interval. All patients were devised into the following two groups according to their mean core temperature within the 72 hours: the HT group with a mean core temperature ≥ 37.5 °C and the LT group with a mean core temperature <37.5 °C. Hemodynamic, respiratory, and laboratory parameters were tested every 6 hours during the first 72 hours after the temperature increased above 38.5 °C.

RESULTS

Thirty-four patients (50.7%) were classified into the HT group, while thirty-three patients (49.3%) were in the LT group. Compared with the HT group, higher mortality rate at Day 28 was observed in the LT group (69.7% vs 35.3%, P = 0.005). Significant difference in the increase of sepsis-related organ failure assessment (SOFA) score was found between of the HT and the LT groups (1.30 ± 0.90 vs 2.30 ± 2.10, P = 0.02). Statistical differences were observed between the two groups in mean core temperature [(37.90 ± 0.30) °C vs (36.80 ± 0.60) °C, P < 0.000 1], mean peripheral temperature [(37.20 ± 0.30) °C vs (36.30 ± 0.60) °C, P < 0.000 1], minimum core temperature [(36.90 ± 0.30)°C vs (35.80 ± 0.60) °C, P < 0.000 1] and minimum peripheral temperature [(36.20 ± 0.40) °C vs (35.50 ± 0.60) °C, P < 0.000 1], but not in maximum core and peripheral temperature.Statistical difference was also shown in troponin I, fibrinogen, partial thromboplastin and activated partial thromboplastin between the two groups. Cox regression analysis revealed that the mean core temperature was the only independent predictor for the mortality rate at Day 28.

CONCLUSION

Body temperature control within the normal range may exert potentially detrimental effect on organ function and prognosis in patients with refractory septic shock with fever.

The FEN1 E359K germline mutation disrupts the FEN1-WRN interaction and FEN1 GEN activity, causing aneuploidy-associated cancers

Polymorphisms and somatic mutations in Flap Endonuclease 1 (FEN1), an essential enzyme involved in DNA replication and repair, can lead to functional deficiencies of the FEN1 protein and a predisposition to cancer. We identified a FEN1 germline mutation which changed residue E359 to K in a patient whose family had a history of breast cancer. We determined that the E359K mutation, which is in the protein-protein domain of FEN1, abolished the interaction of FEN1 with Werner Syndrome protein (WRN), an interaction which is critical for resolving stalled DNA replication forks. Furthermore, although the flap endonuclease activity of FEN1 E359K was unaffected, it failed to resolve bubble structures, which requires the FEN1 gap dependent endonuclease (GEN) activity. To determine the etiological significance of E359K, we established a mouse model containing this mutation. E359K mouse embryonic fibroblasts (MEF) were more sensitive to DNA cross-linking agents that cause replication forks to stall. Cytological analysis suggested that the FEN1-WRN interaction was also required to for telomere stability; mutant cell lines had fragile telomeres, increased numbers of spontaneous chromosomal anomalies and higher frequencies of transformation. Moreover, the incidence of cancer was significantly higher in mice homozygous for FEN1 E359K than in wild-type mice, suggesting that the FEN1 E359K mutation is oncogenic.

Melatonin improved rat cardiac mitochondria and survival rate in septic heart injury

The pathogenesis of septic myocardial depression is complicated. Mitochondrial dysfunction has been suggested to be one of the main reasons for the reduced cardiac function. As melatonin is an antioxidant with the potential to scavenge radicals in mitochondria, we therefore employed a sepsis model, that is, cecal ligation and double puncture (CLP) in rats, to study the melatonin effects on: (i), myocardial mitochondrial function; (ii), heart systolic function; and (iii), prognosis of septic rats. We demonstrate that melatonin treatment (30 mg/kg, 3, 6, 12, 18, 24 hr after CLP) (i) improved myocardial cytochrome c oxidase (CcOX) activity and blood lactate level, (ii) attenuated heart dysfunction with a higher left ventricular ejection fraction (EF), and (iii) promoted 48-h survival of the rats compared to CLP animals with no melatonin treatment. In conclusion, our results show that rat myocardial mitochondrial CcOX activity was depressed during severe sepsis accompanied by myocardial depression characterized by the decline of EF. In septic rats, melatonin increased the CcOX activity, improved heart systolic function, and lowered mortality rate. The clinical use of melatonin in septic myocardial depression should be tested in the future.

Hypoxic preconditioning attenuates global cerebral ischemic injury following asphyxial cardiac arrest through regulation of delta opioid receptor system

This study was designed to investigate whether delta opioid receptor (DOR) is involved in the neuroprotective effect induced by hypoxic preconditioning (HPC) in the asphyxial cardiac arrest (CA) rat model. Twenty-four hours after the end of 7-day HPC, the rats were subjected to 8-min asphyxiation and resuscitated with a standardized method. In the asphyxial CA rat model, HPC improved the neurological deficit score (NDS), inhibited neuronal apoptosis, and increased the number of viable hippocampal CA1 neurons at 24 h, 72 h, or 7 days after restoration of spontaneous circulation (ROSC); however, the above-mentioned neuroprotection of HPC was attenuated by naltrindole (a selective DOR antagonist). The expression of hypoxia-inducible factor-1α (HIF-1α) and DOR, and the content of leucine enkephalin (L-ENK) in the brain were also investigated after the end of 7-day HPC. HPC upregulated the neuronal expression of HIF-1α and DOR, and synchronously elevated the content of L-ENK in the rat brain. HIF-1α siRNA was used to further elucidate the relationship between HIF-1α and DOR in the HPC-treated brain. Knockdown of HIF-1α by siRNA markedly abrogated the HPC induced upregulation of HIF-1α and DOR. The present study demonstrates that the expression of DOR in the rat brain is upregulated by HIF-1α following exposure to 7-day HPC, at the same time, HPC also increases the production of endogenous DOR ligand L-ENK in the brain. DOR activation after HPC results in prolonged neuroprotection against subsequent global cerebral ischemic injury, suggesting a new mechanism of HPC-induced neuroprotection on global cerebral ischemia following CA and resuscitation.

First Report of Gray Mold of Strawberry Caused by Botrytis cinerea in South Carolina

Gray mold caused by Botrytis spp. is one of the most economically important diseases of cultivated strawberry (Fragaria × ananassa) worldwide. From April to June 2011, strawberries with symptoms resembling gray mold disease were collected from different locations (Chesnee, Florence, Lexington, McBee, Monetta, and North Augusta) in South Carolina. Fruit infections began as small, firm, light brown lesions that enlarged quickly, becoming covered with a gray, fuzzy mass of spores followed by a soft rot. To isolate the causal agent, spores from symptomatic fruit were suspended in 1% Tween 20, streaked onto the surface of potato dextrose agar plates, and incubated at 22°C. Fungal colonies from single spores were at first colorless and later became gray to brown when the conidiphores and conidia developed. Conidia were identified by their morphological characteristics: an average size of 14 × 9 μm, ellipsoid to rounded without internal structure, and with a scar on the point of union to the conidiophore (1). Sclerotia produced in culture were hard, dark, irregular shaped, and formed after 2 weeks. The pathogen was identified as Botrytis cinerea Pers.: on the basis of morphology and confirmed by a restriction digest with ApoI of the 413-kb PCR amplification product obtained with BA2f/BA1r primers (2). Koch's postulates were conducted by inoculating 10 surface-sterilized strawberries with a conidial suspension (10⁵ spores/ml) of a randomly chosen B. cinerea isolate previously characterized; 10 control fruit received sterile water without conidia. The inoculated fruit were incubated for 3 days at room temperature in air-tight plastic bags. Inoculated fruit developed typical gray mold symptoms with gray sporulating lesions. The developing spores on inoculated fruit were confirmed to be B. cinerea. All control fruit remained healthy. For many Botrytis spp., the internal transcribed spacer region does not reveal nucleotide variations and thus is useless for species identification. We used additional, more appropriate genetic markers for molecular-based species identification and verified that strawberries in South Carolina are affected by gray mold disease caused by B. cinerea. To our knowledge, this is the first scientific report of B. cinerea causing gray mold of strawberry in South Carolina. References: (1) W. R. Jarvis. Botryotinia and Botrytis Species: Taxonomy, Physiology and Pathogenicity. A Guide to the Literature. Monograph no. 15. Canada Department of Agriculture, Research Branch, Ottawa, 1977. (2) K. Nielsen et al. Plant Dis. 86:682, 2002.

The vascular actions of insulin control its delivery to muscle and regulate the rate-limiting step in skeletal muscle insulin action

Evidence suggests that insulin delivery to skeletal muscle interstitium is the rate-limiting step in insulin-stimulated muscle glucose uptake and that this process is impaired by insulin resistance. In this review we examine the basis for the hypothesis that insulin acts on the vasculature at three discrete steps to enhance its own delivery to muscle: (1) relaxation of resistance vessels to increase total blood flow; (2) relaxation of pre-capillary arterioles to increase the microvascular exchange surface perfused within skeletal muscle (microvascular recruitment); and (3) the trans-endothelial transport (TET) of insulin. Insulin can relax resistance vessels and increase blood flow to skeletal muscle. However, there is controversy as to whether this occurs at physiological concentrations of, and exposure times to, insulin. The microvasculature is recruited more quickly and at lower insulin concentrations than are needed to increase total blood flow, a finding consistent with a physiological role for insulin in muscle insulin delivery. Microvascular recruitment is impaired by obesity, diabetes and nitric oxide synthase inhibitors. Insulin TET is a third potential site for regulating insulin delivery. This is underscored by the consistent finding that steady-state insulin concentrations in plasma are approximately twice those in muscle interstitium. Recent in vivo and in vitro findings suggest that insulin traverses the vascular endothelium via a trans-cellular, receptor-mediated pathway, and emerging data indicate that insulin acts on the endothelium to facilitate its own TET. Thus, muscle insulin delivery, which is rate-limiting for its metabolic action, is itself regulated by insulin at multiple steps. These findings highlight the need to further understand the role of the vascular actions of insulin in metabolic regulation.

Imaging the effects of propofol on human cerebral glucose metabolism using positron emission tomography

The effects of propofol on glucose metabolism in different cerebral regions were observed, using positron emission tomography (PET) technology, to determine a possible cerebral target region. Seven healthy volunteers were injected with (18)F-fluorodeoxyglucose developing agent for PET scanning whilst awake (control group T1), during sedation (induced by 1.5 microg/ml propofol administered by target controlled injection [TCI], group T2) and when unconsciousness (induced by 2.5 microg/ml propofol administered by TCI, group T3). Whole brain glucose metabolism was reduced during propofol anaesthesia; this was initially observed in the cortical areas at the lower dose of propofol (group T2) but extended to the subcortical regions, especially the thalamus and hippocampus, at the higher dose (group T3). This suggests that these regions of the brain might be important targets that are susceptible to propofol.

Biotransformation of (+)- and (-)-camphorquinones by plant cultured cells

Biotransformation of (+)- and (-)-camphorquinones with suspension plant cultured cells of Nicotiana tabacum and Catharanthus roseus was investigated. It was found that the plant cultured cells of N. tabacum and C. roseus reduce stereoselectively the carbonyl group of (+)- and (-)-camphorquinones to the corresponding alpha-keto alcohols.

Biotransformation of thujopsene by Caragana chamlagu

Biotransformation of thujopsene (1) using a cell suspension culture of Caragana chamlagu for 14 days gave mayurone (2, 52%) and two new compounds, 3beta-hydroxy-4-thujopsene (4, 16%) and 3beta-epoxythujopsa-5beta-ol (3, 22%).

NMR studies of mannitol-terminating oligosaccharides derived by reductive alkaline hydrolysis from brain glycoproteins

Interest in the characterisation of O-mannosyl glycan structures has been stimulated following the identification of mannitol-terminating oligosaccharides among the chains released from mammalian proteins in nervous and muscle tissues, and by the discovery of a putative human O-mannosyl transferase. Several mass spectrometry methods have been applied to structure elucidation particularly when low amounts of oligosaccharide are available for analysis. However, when sufficient amounts are available, a combination of through-bond homo- and heteronuclear, and of through-space homonuclear NMR experiments permit the complete identification of these oligosaccharide sequences. We describe here the assignment of 1H and 13C NMR chemical shifts from such experiments for four mannitol-terminating oligosaccharide alditols, GlcNAcbeta-(1-->2)Manol, Galbeta-(1-->4)GlcNAcbeta-(1-->2)Manol, Galbeta-(1-->4)[Fucalpha-(1-->3)]GlcNAcbeta-(1-->2)Manol and NeuAcalpha-(2-->3)Galbeta-(1-->4)GlcNAcbeta-(1-->2)Manol, that were released from brain glycopeptides by alkaline borohydride treatment.

10E4 antigen of Scrapie lesions contains an unusual nonsulfated heparan motif

The carbohydrate antigen on heparan sulfate recognized by monoclonal antibody 10E4 is uniquely codistributed with the abnormal prion protein, PrP(Sc), even in the earliest detectable brain lesions of scrapie-infected mice. Determining the chemical structure of 10E4 antigen is, therefore, an important aspect of structure elucidation of scrapie lesions, and a prerequisite for designing experiments to understand its role in scrapie pathogenesis. Toward this aim, we have examined preparations of heparan sulfate, with differing sulfate contents, for binding by 10E4 antibody. The highest antigenicity was observed in a preparation (HS-1) with the lowest sulfate content. HS-1 was partially depolymerized with heparin lyase III, and oligosaccharide fragments examined for 10E4 antigen expression by the neoglycolipid technology. An antigen-positive and two antigen-negative tetrasaccharides were isolated and examined by electrospray mass spectrometry. The antigen-positive tetrasaccharide sequence on heparan sulfate was thus deduced to contain a unique unsulfated motif that includes an N-unsubstituted glucosamine in the sequence, UA-GlcN-UA-GlcNAc. Antibody binding experiments with neoglycolipids prepared from a series of heparin/heparan sulfate disaccharides, and the trisaccharide derived from the antigen-positive tetrasaccharide after removal of the terminal hexuronic acid, show that both the penultimate glucosamine and the outer nonsulfated hexuronic acid are important for 10E4 antigenicity.

Cloning and pharmacological characterization of a fourth histamine receptor (H(4)) expressed in bone marrow

Histamine is a multifunctional hormone that regulates smooth muscle contraction in the airways, acid secretion in the gut, and neurotransmitter release in the central nervous system through three well characterized receptor subtypes, H(1), H(2), H(3), respectively. As part of a directed effort to discover novel G-protein-coupled receptors through homology searching of genomic databases, we identified a partial clone (GPCR105) that had significant homology to the recently identified histamine H(3) receptor cDNA. Expression of the full-length human GPCR105 in cells confers the ability to bind [(3)H]histamine with high affinity (K(D) = 5 nM). GPCR105 is pharmacologically similar to the histamine H(3) receptor in that it binds many of the known H(3) agonists and antagonists, albeit with a different rank order of affinity/potency. GPCR105 does not bind (i.e., K(D) > 10 microM) all tested H(1) and H(2) receptor antagonists such as diphenhydramine, loratadine, ranitidine, and cimetidine, but has modest affinity for the H(2) receptor agonist, dimaprit (377 nM). Whereas the H(3) receptor is expressed almost exclusively in nervous tissues, GPRC105 is expressed primarily in bone marrow and eosinophils. Together, these data demonstrate that GPCR105 is a novel histamine receptor structurally and pharmacologically related to the H(3) receptor. However, its unique expression profile and physiological role suggest that GPCR105 is a fourth histamine receptor subtype (H(4)) and may be a therapeutic target for the regulation of immune function, particularly with respect to allergy and asthma.

Negative-ion electrospray mass spectrometry of neutral underivatized oligosaccharides

Negative-ion electrospray mass spectrometry (ES-MS) with collision-induced dissociation (CID) and MS/MS scanning on a quadrupole-orthoganal time-of-flight instrument provide a sensitive means for structural analysis of neutral underivatized oligosaccharides. Molecular mass information can be readily obtained from the dominant [M - H]- ions in the ES mass spectrum formed with subnanomole amounts of oligosaccharides, and similar sensitivity is available from CID-MS/MS to give structural details. The CID spectra of 14 oligosaccharides demonstrated that sequence and partial linkage information can be derived and isomeric structures can be differentiated. Series of C-type fragment ions give sequence information while the double glycosidic D-type cleavage of a 3-linked GlcNAc or Glc and the saccharide ring fragmentation of the 0,2A-type from 4-linked GlcNAc or Glc can provide partial linkage information. The distinctive D- and A-cleavages are important for differentiation of oligosaccharide type 1 and type 2 chains and to define the blood group H, Le(a), Le(x), Le(b), and Le(y) determinants carried by their fucosylated analogues.

Expression of glycoconjugates bearing the Lewis X epitope during neural differentiation of P19 EC cells

The Lewis X (Le(x)) bearing glycolipids were noticeably increased in amounts during the course of neural differentiation of P19 EC cells induced by retinoic acid (RA, all-trans form). Applying neoglycolipid technology and in situ TLC-LSIMS, the oligosaccharide chains of these scarce Le(x) bearing glycolipids were partially characterized after released by endoglycoceramidase and subsequent conversion into neoglycolipids. In order to understand the enzymatic basis for the expression of Le(x) bearing glycolipids, we measured glycolipid, glycoprotein and oligosaccharide fucosyltransferase (Fuc-T) activities using appropriate substrates in P19 EC cells with or without RA treatment. All three Fuc-Ts were increased after RA treatment and the highest activity was in the differentiated neural cells. We then investigated the two possible Fuc-T genes that might be responsible for these changes using RT-PCR analysis. Mouse Fuc-TIX (mFuc-TIX) transcript was detected in all cell types but it was only strongly expressed in RA-induced aggregates and neural cells. In the case of mouse Fuc-TIV (mFuc-TIV) gene, its transcript was only detectable in RA-induced aggregates and not found in either undifferentiated or RA-induced neural cells. These results strongly support that RA induces only a transient expression of the mFuc-TIV gene in cell aggregates but a more persistent expression of the mFuc-TIX gene at the transcription level throughout neural cell differentiation. The mFuc-TIX gene is probably the main cause for the increased expression of Le(x) glycoconjugates during neural differentiation of P19 EC cells.

Inhibition of adhesion of Plasmodium falciparum-infected erythrocytes by structurally defined hyaluronic acid dodecasaccharides

We recently reported that Plasmodium falciparum-infected erythrocytes (IRBCs) can adhere to hyaluronic acid (HA), which appears to be a receptor, in addition to chondroitin sulfate A (CSA), for parasite sequestration in the placenta. Further investigations of the nature and specificity of this interaction indicate that HA oligosaccharide fragments competitively inhibit parasite adhesion to immobilized purified HA in a size-dependent manner, with dodecasaccharides being the minimum size for maximum inhibition. Rigorously purified and structurally defined HA dodecasaccharides, free of contamination by CSA or other glycosaminoglycans, effectively inhibited IRBC adhesion to HA but not CSA, providing compelling evidence of a specific interaction between IRBCs and HA.