Impact of the implementation of the Intelligent Antimicrobial System (iAMS) on clinical outcomes among patients with bacteraemia caused by methicillin-resistant Staphylococcus aureus

OBJECTIVES

This study aimed to investigate the clinical impact of the Intelligent Antimicrobial System (iAMS) on patients with bacteraemia due to methicillin-resistant (MRSA) and methicillin-susceptible Staphylococcus aureus (MSSA).

METHODS

A total of 1008 patients with suspected SA infection were enrolled before and after the implementation of iAMS. Among them, 252 with bacteraemia caused by SA, including 118 in the iAMS and 134 in the non-iAMS groups, were evaluated.

RESULTS

The iAMS group exhibited a 5.2% (from 55.2% to 50.0%; P = 0.96) increase in the 1-year survival rate. For patients with MRSA and MSSA compared to the non-iAMS group, the 1-year survival rate increased by 17.6% (from 70.9% to 53.3%; P = 0.41) and 7.0% (from 52.3% to 45.3%; P = 0.57), respectively, both surpassing the rate of the non-iAMS group. The iAMS intervention resulted in a higher long-term survival rate (from 70.9% to 52.3%; P = 0.984) for MRSA patients than for MSSA patients. MRSA patients experienced a reduced length of hospital stay (from 23.3% to 35.6%; P = 0.038), and the 45-day discharge rate increased by 20.4% (P = 0.064). Furthermore, the intervention resulted in a significant 97.3% relative decrease in near miss medication incidents reported by pharmacists (P = 0.013).

CONCLUSIONS

Implementation of iAMS platform improved long-term survival rates, discharge rates, hospitalization days, and medical cost (although no significant differences were observed) among patients with MRSA bacteraemia. Additionally, it demonstrated significant benefits in ensuring drug safety.

Efficacy of cefoperazone/sulbactam for ESBL-producing Escherichia coli and Klebsiella pneumoniae bacteraemia and the factors associated with poor outcomes

OBJECTIVE

We aimed to assess the efficacy of cefoperazone/sulbactam (CPZ/SUL) in extended-spectrum β-lactamase (ESBL)-producing Enterobacterales infections and identify factors influencing outcomes.

METHODS

This retrospective multicentre study was conducted in Taiwan (January 2015 to December 2020) and examined the efficacy of CPZ/SUL treatment in ESBL-producing Enterobacterales bacteraemia. The minimum inhibitory concentrations (MICs) were determined using agar dilution; ESBL/AmpC genes were detected using polymerase chain reaction. The primary outcome was clinical success, whereas the secondary outcome was 30-day mortality. Clinical success was defined as the complete resolution of clinical signs and symptoms of K. pneumoniae or E. coli infection, with no evidence of persistent or recurrent bacteraemia. The factors influencing outcomes were identified using a multivariate analysis.

RESULTS

CPZ/SUL demonstrated a clinical success rate of 82.7% (91/110) in treating ESBL-producing Enterobacterales bacteraemia, with a 30-day mortality rate of 9.1% (10/110). Among 110 ESBL-producing isolates, a high clinical success rate was observed at an MIC of ≤32/32 mg/L. Multivariate analysis revealed that a Charlson comorbidity index (CCI) of ≥6 was associated with lower clinical success [odds ratio (OR): 5.80, 95% confidence interval (CI): 1.15-29.14, P = 0.033]. High Sequential Organ Failure Assessment scores (≥6) were significantly associated with increased 30-day mortality (OR: 14.34, 95% CI: 1.45-141.82, P = 0.023).

DISCUSSION

CPZ/SUL demonstrated a clinical success rate of 82.7% (91/110) in treating ESBL-producing Enterobacterales bacteraemia. Treatment success was evident when the CPZ and SUL MIC was ≤32/32 mg/L. Comorbidities (CCI ≥6) were associated with lower clinical success, while disease severity (Sequential Organ Failure Assessment score ≥6) correlated with higher mortality.

The effects of introducing virtual reality communication simulation in students' learning in a fundamentals of nursing practicum: A pragmatic randomized control trials

AIM

This study was conducted to examine the effectiveness of a virtual reality communication simulation (VRCS) in teaching communication skills in fundamentals of nursing practicum.

BACKGROUND

Effective communication skills are an integral part of the nursing profession and the foundation of high-quality nursing care. Effective communication not only addresses the needs of patients but is also necessary for maintaining patient safety. Many studies have reported the inadequacy of nursing students in communicating with patients. Nursing students often experience stress due to their lack of adequate skills to communicate effectively with patients and their family members.

DESIGN

A pragmatic randomized controlled trial research with four within-subjects assessments (at the baseline (T0), 1st week (T1) and 3rd week (T2) of the clinical practice and 1 week after the end of the clinical practice (T3)) and between-subjects assessments.

SETTINGS AND PARTICIPANTS

Eighty-four nursing students at a university of Science and Technology in central Taiwan.

METHODS

The students were randomly assigned to an experimental group (n = 42) and a control group (n = 42). The experimental group received a VRCS, whereas the control group received the nurse-patient communication teaching video. The data were collected from April 2022 to August 2022. The Kalamazoo Essential Element Communication Checklist, Communication Self-Assessment Scale, Learning Satisfaction Questionnaire and Stress Scale for Nursing Students in Clinical Practice were used for data collection.

RESULTS

At baseline, the control group had higher scores on communication ability and confidence compared with the experimental group (t = -3.91, p <.001; and t = -2.35, p =.021). In the first week of clinical practice, the experimental group had significantly higher mean scores for communication ability compared with the control group (β = 15.99, 95 % confidence interval [CI] 13.79, 18.18) and communication confidence and learning satisfaction compared with controls at T1, T2 and T3 of the clinical practice (all, p <.001). The clinical practice stress scores of the experimental group were significantly lower than those of the control group at T1, T2 and T3 of the clinical practice (all, p <.05).

CONCLUSIONS

The newly developed VRCS is acceptable and worthwhile for training nursing students to develop communication abilities. This study suggests that VRCS practice should be arranged as early as possible in fundamentals of nursing practice courses and before the fundamentals of nursing practicum so as to facilitate the learning of effective communication. Follow-up research is needed to evaluate the long-term effects of virtual reality education in nursing practice.

Immune responses and safety of COVID-19 vaccination in atypical hemolytic uremic syndrome patients in Taiwan

Atypical hemolytic uremic syndrome is a rare, life-threatening disorder which can be triggered by COVID 19 infection and COVID 19 vaccination then induce multiple organ failure. Our study is the first to evaluate immune responses to COVID-19 vaccination and safety in a cohort of patients in a local single-center study in Taiwan.. Results indicate that vaccines effectively shield aHUS patients from severe COVID-19 complications without significant safety concerns. A double booster dose for the third vaccine is essential for optimal efficacy. Anti-complement therapy did not influence vaccination effectiveness. Transplant aHUS patients had the lowest immune response titers, indicating a need for additional vaccine doses. Compared to healthcare workers, aHUS patients had poor T-cell responses. We noted a superior trend with mixed-type COVID-19 vaccinations in aHUS patients, while fixed-type mRNA demonstrated better results in healthcare workers. Our findings endorse COVID-19 vaccination as a potent strategy to safeguard aHUS patients from severe complications, emphasizing the importance of vigilant monitoring pre- and post-vaccination.

High-titer anti-interferon-γ neutralizing autoantibodies linked to opportunistic infections in patients with adult-onset still's disease

Objective

Neutralizing anti-interferon (IFN)-γ autoantibodies are linked to opportunistic infections (OIs). To explore the association between anti-IFN-γ autoantibodies and OIs in patients with adult-onset Still's disease (AOSD), we aimed to examine the ability of these autoantibodies to blockade signal transducer and activator of transcription (STAT1)-phosphorylation and chemokines production.

Methods

Serum titers of anti-IFN-γ autoantibodies were quantified using ELISA in 29 AOSD and 22 healthy controls (HC). The detectable autoantibodies were verified with immunoblotting assay, and their neutralizing capacity against IFN-γ-signaling was evaluated with flow-cytometry analysis and immunoblotting. IFN-γ-mediated production of supernatant chemokines, including monocyte chemoattractant protein-1 (MCP-1) and IFN-γ inducible protein-10 (IP-10), were measured by ELISA.

Results

Among 29 AOSD patients, high titers of anti-IFN-γ neutralizing autoantibodies were detectable in two patients with OIs. Immunoblotting assay revealed more effective inhibition of STAT1-phosphorylation in THP-1 cells treated with sera from autoantibody-positive AOSD patients (56.7 ± 34.79%) compared with those from HC (104.3 ±29.51%), which was also demonstrated in flow-cytometry analysis (47.13 ± 40.99 vs. 97.92 ± 9.48%, p < 0.05). Depleted serum IgG from anti-IFN-γ autoAbs-positive AOSD patients with OIs restored phosphorylated STAT-1 upon IFN-γ treatment. Sera from autoantibody-positive AOSD patients more effectively inhibited IFN-γ-mediated production of MCP-1 (45.65 pg/ml) and IP-10 (22.44 pg/ml) than sera from HC (263.1 pg/ml and 104.0 pg/ml, both p < 0.05). Serum samples showing the strongest inhibition of IFN-γ-signaling were from two patients with high-titer autoantibodies and OIs.

Conclusion

AOSD patients have a high positive rate and titers of anti-IFN-γ autoantibodies. The remarkable blockade effect of high-titer autoantibodies on IFN-γ-mediated STAT1-phosphorylation and chemokines could make these patients susceptible to OIs.

Changing epidemiology and prognosis of nosocomial bloodstream infection: A single-center retrospective study in Taiwan

BACKGROUND

Nosocomial bloodstream infection (BSI) remains a significant cause of mortality and morbidity. We evaluate the trend of the pathogens of nosocomial BSI and investigate the distribution of the pathogens to demonstrate the risk factors of mortality.

METHODS

In this retrospective study, we collected data from a 2076-bed tertiary referral center that offers a full range of clinical services in central Taiwan during January, 2016 to December, 2017.

RESULTS

Five hundred and eighty-four patients were identified with nosocomial BSI. Among the comorbidities of nosocomial BSI patients with, the most frequent were hypertension, in 294 patients (50.3%), malignancy, in 279 patients (47.8%); diabetes, in 278 patients (47.6%); chronic kidney disease, in 171 patients (29.3%); and liver cirrhosis, in 132 patients (22.6%). Gram-positive organisms caused 22.9% of these nosocomial BSIs, gram-negative organisms caused 69.2%, and fungi caused 6.8%. The most common organism causing nosocomial BSIs were Klebsiella spp. (14%), E coli. (14%), and Enterococcus spp. (11%). Multivariate analysis of risk factors for mortality displayed that comorbidity with low body weight, liver cirrhosis, and malignancy, high CRP level, high Charlson Comorbidity Index and internal medicine and hematology/oncology distribution were strikingly associated with mortality (P = 0.0222, 0.0352, 0.0008, 0.0122, <0.001, and 0.041; [OR] = 1.8097, 1.9268, 2.7156, 2.7585, 3.5431, and 2.2449, respectively).

CONCLUSION

K. spp. and E coli. became the most common pathogens of nosocomial BSI in recent years. Comorbidities could be important roles to predictive the outcome of nosocomial BSI. The modifiable risk factors of nosocomial BSI may be investigated further to improve the outcome.

Patterns of genetic variation and QTLs controlling grain traits in a collection of global wheat germplasm revealed by high-quality SNP markers

BACKGROUND

Establish a molecular breeding program involved assembling a diverse germplasm collection and generating accurate genotypes to characterize their genetic potential and associate them with agronomic traits. In this study, we acquired over eight hundred wheat accessions from international gene banks and assessed their genetic relatedness using high-quality SNP genotypes. Understanding the scope of genomic variation in this collection allows the breeders to utilize the genetic resources efficiently while improving wheat yield and quality.

RESULTS

A wheat diversity panel comprising 39 durum wheat, 60 spelt wheat, and 765 bread wheat accessions was genotyped on iSelect 90 K wheat SNP arrays. A total of 57,398 SNP markers were mapped to IWGSC RefSeq v2.1 assembly, over 30,000 polymorphic SNPs in the A, B, D genomes were used to analyze population structure and diversity, the results revealed the separation of the three species and the differentiation of CIMMYT improved breeding lines and landraces or widely grown cultivars. In addition, several chromosomal regions under selection were detected. A subset of 280 bread wheat accessions was evaluated for grain traits, including grain length, width, surface area, and color. Genome-wide association studies (GWAS) revealed that several chromosomal regions were significantly linked to known quantitative trait loci (QTL) controlling grain-related traits. One of the SNP peaks at the end of chromosome 7A was in strong linkage disequilibrium (LD) with WAPO-A1, a gene that governs yield components.

CONCLUSIONS

Here, the most updated and accurate physical positions of SNPs on 90 K genotyping array are provided for the first time. The diverse germplasm collection and associated genotypes are available for the wheat researchers to use in their molecular breeding program. We expect these resources to broaden the genetic basis of original breeding and pre-breeding materials and ultimately identify molecular markers associated with important agronomic traits which are evaluated in diverse environmental conditions.

Phosphate transporter PHT1;1 is a key determinant of phosphorus acquisition in Arabidopsis natural accessions

Phosphorus (P) is a mineral nutrient essential for plant growth and development, but most P in the soil is unavailable for plants. To understand the genetic basis of P acquisition regulation, we performed genome-wide association studies (GWASs) on a diversity panel of Arabidopsis (Arabidopsis thaliana). Two primary determinants of P acquisition were considered, namely, phosphate (Pi)-uptake activity and PHOSPHATE TRANSPORTER 1 (PHT1) protein abundance. Association mapping revealed a shared significant peak on chromosome 5 (Chr5) where the PHT1;1/2/3 genes reside, suggesting a connection between the regulation of Pi-uptake activity and PHT1 protein abundance. Genes encoding transcription factors, kinases, and a metalloprotease associated with both traits were also identified. Conditional GWAS followed by statistical analysis of genotype-dependent PHT1;1 expression and transcriptional activity assays revealed an epistatic interaction between PHT1;1 and MYB DOMAIN PROTEIN 52 (MYB52) on Chr1. Further, analyses of F1 hybrids generated by crossing two subgroups of natural accessions carrying specific PHT1;1- and MYB52-associated single nucleotide polymorphisms (SNPs) revealed strong effects of these variants on PHT1;1 expression and Pi uptake activity. Notably, the soil P contents in Arabidopsis habitats coincided with PHT1;1 haplotype, emphasizing how fine-tuned P acquisition activity through natural variants allows environmental adaptation. This study sheds light on the complex regulation of P acquisition and offers a framework to systematically assess the effectiveness of GWAS approaches in the study of quantitative traits.

Correlation Between Cefoperazone/Sulbactam MIC Values and Clinical Outcomes of Escherichia coli Bacteremia

INTRODUCTION

The clinical efficiency of cefoperazone/sulbactam (CPZ/SUL) against Escherichia coli bacteremia was unknown. This study aimed to explore the relationship between CPZ/SUL MIC values and clinical outcomes in Escherichia coli bacteremia.

METHODS

A multicenter, retrospective, observational cohort study was conducted in Taiwan between January 2015 and December 2020. Patients treated with CPZ/SUL for E. coli bacteremia were enrolled in the analysis. The CPZ/SUL MICs were determined by using the agar dilution method. The primary outcome was 30-day mortality.

RESULTS

Among 247 isolates, 160 (64.8%) isolates were susceptible, 8 (3.2%) were intermediate, and 79 (32.0%) were resistant to cefoperazone. The activity of cefoperazone against cefoperazone-non-susceptible E. coli (n = 87) was restored upon combination with sulbactam, with susceptibility ranging from 0% to 97.7%. The 30-day mortality was 4.5% (11/247) and overall clinical success rate was 91.9% (227/247). Multivariate Cox proportional-hazards model revealed that heart failure [adjusted relative risk (ARR), 5.49; 95% confidence interval (CI) 1.31-23.02; p = 0.020], malignancy (ARR 7.50; 95% CI 2.02-27.80; p = 0.003), SOFA score (ARR 1.29; 95% CI 1.09-1.52; p = 0.003), and CPZ/SUL MIC ≥ 64 mg/L (ARR 11.31; 95% CI 1.34-95.52; p = 0.026) were independently associated with 30-day mortality. No statistically significant differences in 30-day mortality were found between groups with or without cefoperazone susceptibility (3.4% vs. 5.0%, p = 0.751, respectively).

CONCLUSIONS

Patients with E. coli bacteremia who were treated with CPZ/SUL had a favorable outcome when the MICs of the isolates were ≤ 16 mg/L and a high risk of mortality with MICs ≥ 64 mg/L.

Association between angiotensin-converting enzyme inhibitors or angiotensin receptor blockers and community-acquired pneumonia: A nationwide population propensity-score matching study

BACKGROUND

Few large-scale cohort studies have investigated the association between community-acquired pneumonia and the use of angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs). We aimed to study whether using ACEIs or ARBs had protective effects for community-acquired pneumonia.

METHODS

This database cohort study was conducted retrospectively in Taiwan. The hypertensive patients were the target population of this study. Patients with ARB use were defined as our first study cohort. The second study cohort comprised patients who used ACEI. Propensity-score matching at 1:1 was used between ARB users and non-ARB users. We recruited 67 944 participants for the ARB study and 58 062 participants for the ACEI study. The same matching was also performed between ACEI users and non-ACEI users. Cox proportional hazard regression was used to analyse the risk of the outcome of viral pneumonia.

RESULTS

The hazard ratio of community-acquired pneumonia for ARB users relative to non-ARB users was 0.33. The hazard ratio of community-acquired pneumonia was 0.71 times in ACEI users compared with ACEI nonusers. In stratification analysis, both ARB and ACEI both exhibited a protective effect for community-acquired pneumonia in each age and sex group. In the analysis of the effects of therapy duration, patients using ARB for fewer than 100 days exhibited a greater reduction in the risk of community-acquired pneumonia (adjusted HR = 0.58) compared with the non-ARB cohort. For the ACEI study, patients who used ACEI for 121-450 days were more likely to exhibit reduced risks of community-acquired pneumonia (adjusted HR = 0.5).

CONCLUSION

Both ACEI and ARB uses were associated with decreased risk of community-acquired pneumonia infection.

The epidemiology, genotypes, antifungal susceptibility of Trichosporon species, and the impact of voriconazole on Trichosporon fungemia patients

BACKGROUND/PURPOSE

Invasive Trichosporon infections are emerging, but association of different therapeutic management of Trichosporon fungemia and clinical outcomes were rarely reported. This study investigates the epidemiology, species distribution and genotypes of trichosporonosis in Taiwan, and identified the predictors of clinical outcomes in patients with Trichosporon fungemia.

METHODS

Strains collected from four medical centers in Taiwan, during 2010-2018. Species identification was confirmed by sequencing of IGS1 region, and antifungal susceptibility was performed using Sensititre YeastOne panel.

RESULTS

Among 115 isolates, Trichosporon asahii was the leading species (73.0%), followed by Trichosporon dermatis (11.3%), Trichosporon faecales (6.1%), and Trichosporon montevideense (5.2%). Of the 84 T. asahii isolates, genotype 1 was the predominant (41.7%). High fluconazole minimal inhibitory concentration (MICs,≧8 μg/mL) were observed for 70.2% T. asahii isolates and 16.1% non-asahii Trichosporon isolates. Posaconazole and voriconazole possess the most potent antifungal activity against all Trichosporon isolates, with geometric mean values of 0.251 μg/mL and 0.111 μg/mL, respectively. Fifty-three isolates collected from blood cultures, and 42 patients with fungemia enrolled for the Kaplan-Meier plot which revealed that voriconazole treatment had a significantly better survival rate compared with those without (p = 0.042). In multivariate analysis, source control (odds ratio [OR]: 0.13 95%CI [confidence interval]: 0.02-0.83, p = 0.031) and voriconazole use (OR: 0.11 95%CI: 0.02-0.74, p = 0.023) are independent predictors of 14-day mortality.

CONCLUSION

This is the largest series of Trichosporon fungemia up till the present moment. Voriconazole therapy and source control play important roles in 14-day mortality.

Risk of Viral Infection in Patients Using Either Angiotensin-converting Enzyme Inhibitors or Angiotensin Receptor Blockers: A Nationwide Population-based Propensity Score Matching Study

BACKGROUND

We hypothesized that renin-angiotensin system (RAS) blockers have systemic protective effects beyond the respiratory tract and could reduce the risk of viral infections.

METHODS

We used the National Health Insurance Research Database and identified 2 study cohorts: the angiotensin receptor blocker (ARB) cohort and angiotensin-converting enzyme inhibitor (ACEI) cohort. Propensity score matching was applied at a 1:1 ratio by all associated variables to select 2 independent control cohorts for the ARB and ACEI cohorts. A Cox proportional hazards model was applied to assess the end outcome of viral infection.

RESULTS

The number of ARB and ACEI users was 20 207 and 18 029, respectively. The median age of ARB users and nonusers was 53.7 and 53.8 years, respectively. The median follow-up duration of ARB users and nonusers was 7.96 and 7.08 years; the median follow-up duration of ACEI users and nonusers was 8.70 and 8.98 years, respectively. The incidence rates of viral infections in ARB users and nonusers were 4.95 and 8.59 per 1000 person-years, respectively, and ARB users had a lower risk of viral infection than nonusers (adjusted hazard ratio [aHR], 0.53 [95% confidence interval {CI}, .48-.58]). The incidence rates of viral infections in ACEI users and nonusers were 6.10 per 1000 person-years and 7.72 per 1000 person-years, respectively, and ACEI users had a lower risk of viral infection than nonusers (aHR, 0.81 [95% CI, .74-.88]).

CONCLUSIONS

Hypertensive patients using either ARBs or ACEIs exhibit a lower risk of viral infection than nonusers.

GAD65 as a potential marker for cognitive performance in an adult population with prediabetes

BACKGROUND

Diabetes mellitus (DM) is a well-known risk factor for cognitive dysfunction in aged populations. However, there are inconsistent reports about impaired fasting glucose or prediabetes as an independent risk factor for cognitive function. Glutamic acid decarboxylase 65 (GAD65) is the key enzyme responsible for γ-aminobutyric acid synthesis in the central nervous system. Antibodies against GAD65 (GAD65Abs) are not only detected in approximately 80% of early-onset type 1 DM, but also linked to several neurological disorders.

AIM

This study aims to investigate the association between GAD65Ab titer levels and cognitive performance. In addition, we assessed the effect of GAD65Ab on cognitive function in adults with normal fasting glucose, prediabetes and DM.

METHODS

A total of 328 subjects aged 49.10 ± 5.72 years were enrolled from the Third Health and Nutrition Examination Survey dataset. Cognitive performance was assessed by three computerized neurobehavioral tests, including the serial digit learning test, simple reaction time test (SRTT) and symbol-digit substitution test (SDST).

RESULTS

Subjects with higher GAD65Ab titers had significantly poorer cognitive function in the SRTT and SDST (P < 0.05). Additionally, GAD65Ab was associated with cognitive decline in non-diabetic adults after adjusting for a number of relevant variables (P < 0.05 in both SRTT and SDST).

CONCLUSIONS

These results indicate that GAD65Ab may be a potential marker for cognitive impairment in non-diabetic adults.

Epidemiology and risk factors for invasive fungal infections during induction chemotherapy for newly diagnosed acute myeloid leukemia: A retrospective cohort study

This study investigated the epidemiology and risk factors associated with invasive fungal infections (IFIs) during induction chemotherapy in a cohort of Taiwanese patients with newly-diagnosed acute myeloid leukemia (AML). IFIs are a significant complication in the management of immunocompromised cancer patients; such infections are associated with a high incidence of morbidity and mortality, particularly in many South-Asian countries, where IFI rates are increasing. We retrospectively analyzed IFI incidence data from 105 patients with newly diagnosed AML at a single center undergoing their first course of induction chemotherapy without primary antifungal prophylaxis between November 2008 and December 2014. Of 21 cases documented as proven/provable IFIs 16 (76%) were invasive aspergillosis, 2 (10%) were mucormycosis infections, and 3 (14%) were proven yeast infections. The lung was the most commonly affected site (n = 16; 76%); 2 patients (10%) developed fungal sinusitis. IFI cases were more often males (P = 0.020). In multivariate analysis, patients with neutropenia lasting>30 days were more than twice as likely to develop IFI (OR, 2.24 [95% CI, 2.81-31.11], P<0.001). We also confirmed patients with smoker and receiving parenteral nutrition during chemotherapy were significant associated with IFIs. Our findings suggest that antifungal prophylaxis should be considered for patients with AML during induction chemotherapy, particularly in patients from Southeastern Asia, an area of potentially high IFI rates. We recommend that clinicians determine which patients receiving induction chemotherapy for AML are at high risk of developing IFI, to allow for targeted therapeutic prophylaxis.

Quantum thermodynamics from the nonequilibrium dynamics of open systems: Energy, heat capacity, and the third law

In a series of papers, we intend to take the perspective of open quantum systems and examine from their nonequilibrium dynamics the conditions when the physical quantities, their relations, and the laws of thermodynamics become well defined and viable for quantum many-body systems. We first describe how an open-system nonequilibrium dynamics (ONEq) approach is different from the closed combined system +  environment in a global thermal state (CGTs) setup. Only after the open system equilibrates will it be amenable to conventional thermodynamics descriptions, thus quantum thermodynamics (QTD) comes at the end rather than assumed in the beginning. The linkage between the two comes from the reduced density matrix of ONEq in that stage having the same form as that of the system in the CGTs. We see the open-system approach having the advantage of dealing with nonequilibrium processes as many experiments in the near future will call for. Because it spells out the conditions of QTD's existence, it can also aid us in addressing the basic issues in quantum thermodynamics from first principles in a systematic way. We then study one broad class of open quantum systems where the full nonequilibrium dynamics can be solved exactly, that of the quantum Brownian motion of N strongly coupled harmonic oscillators, interacting strongly with a scalar-field environment. In this paper, we focus on the internal energy, heat capacity, and the third law. We show for this class of physical models, amongst other findings, the extensive property of the internal energy, the positivity of the heat capacity, and the validity of the third law from the perspective of the behavior of the heat capacity toward zero temperature. These conclusions obtained from exact solutions and quantitative analysis clearly disprove claims of negative specific heat in such systems and dispel allegations that in such systems the validity of the third law of thermodynamics relies on quantum entanglement. They are conceptually and factually unrelated issues. Entropy and entanglement will be the main theme of our second paper on this subject matter.

Clinical characteristics, treatments, and outcomes of hematogenous pyogenic vertebral osteomyelitis, 12-year experience from a tertiary hospital in central Taiwan

BACKGROUND

In Taiwan, studies about hematogenous pyogenic vertebral osteomyelitis (HPVO) are limited. We conducted a retrospective study to evaluate the clinical presentations, treatment, and outcomes of patients with the diagnosis of HPVO.

METHOD

This 12.5-year retrospective study included patients with a diagnosis of HPVO. Medical records of all HPVO patients were thoroughly reviewed and their clinical data were analyzed by the SPSS software.

RESULT

414 HPVO cases were included and the mean age was 61.6 ± 13.4 years. The mean duration of symptoms was 29 ± 35.3 days and pain over the affected site was reported by most patients (86.0%). Gram-positive bacteria, especially Staphylococcus aureus (162/399 = 40.6%), were the main HPVO pathogens. Escherichia coli (42/399 = 10.5%) was the most common gram-negative isolate. Surgery was performed in 68.8% of cases and the mean duration of total antibiotic treatment was 104.7 ± 77.7 days. All-cause mortality and recurrence rates were 6.3% and 18.8%, respectively. In multivariate analysis, polymicrobial infection (OR: 4.154, 95% CI: 1.039-16.604, p = 0.044), multiple vertebral body involvement (OR: 2.202, 95% CI: 1.088-4.457, p = 0.028), abscess formation treated with antibiotics alone (OR: 2.912, 95% CI: 1.064-7.966, p = 0.037), and the duration of antimicrobial treatment less than 4 weeks (OR: 3.737, 95% CI: 1.195-11.683, p = 0.023) were associated with HPVO recurrence.

CONCLUSION

In Taiwan, HPVO mainly affected the elderly and S. aureus remained the most common HPVO pathogen. In patients with risk factors associated with HPVO recurrence, a longer duration (≥6 weeks) of antimicrobial therapy is suggested.

Determinants of women's likelihood of vaginal self-sampling for human papillomavirus to screen for cervical cancer in Taiwan: a cross-sectional study

Background

Many Taiwanese women (43.8%) did not participate in regular cervical screening in 2011. An alternative to cervical screening, self-sampling for human papillomavirus (HPV), has been available at no cost under Taiwan’s National Health Insurance since 2010, but the extent and likelihood of HPV self-sampling were unknown.

Methods

A cross-sectional study was performed to explore determinants of women’s likelihood of HPV self-sampling. Data were collected by questionnaire from a convenience sample of 500 women attending hospital gynecologic clinics in central Taiwan from June to October 2012. Data were analyzed by descriptive statistics, chi-square test, and logistic regression.

Results

Of 500 respondents, 297 (59.4%) had heard of HPV; of these 297 women, 69 (23%) had self-sampled for HPV. Among the 297women who had heard of HPV, 234 (78.8%) considered cost a priority for HPV self-sampling. Likelihood of HPV self-sampling was determined by previous Pap testing, high perceived risk of cervical cancer, willingness to self-sample for HPV, high HPV knowledge, and cost as a priority consideration.

Conclusions

Outreach efforts to increase the acceptability of self-sampling for HPV testing rates should target women who have had a Pap test, perceive themselves at high risk for cervical cancer, are willing to self-sample for HPV, have a high level of HPV knowledge, and for whom the cost of self-sampling covered by health insurance is a priority.

Electronic supplementary material

The online version of this article (doi:10.1186/s12905-014-0139-0) contains supplementary material, which is available to authorized users.

Management and outcome of adults with skin and soft tissue infection caused by methicillin-resistant Staphylococcus aureus in a tertiary hospital in central Taiwan

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) has been increasingly causing skin and soft tissue infections (SSTIs). Only limited studies have made comparisons between incision and drainage (I&D) alone and I&D with adjunctive antibiotic therapy for treatment effects, and most of the studies were conducted before the emergence of MRSA. This study was to evaluate whether antibiotics provide added benefit to I&D alone for purulent MRSA SSTIs.

METHODS

This retrospective study collected data on SSTI patients, including patient demographics, treatment strategies, antibiotic susceptibilities of the infecting MRSA isolates, and clinical outcomes over the course of 24 months.

RESULTS

Antimicrobial drug susceptibility rate were 100% for vancomycin, teicoplanin, and linezolid. Among the 211 patients, 7.6% were treated solely with I&D (Group A), 62.6% were treated via I&D with adjunctive antibiotic (Group B), and 29.8% patients received only antibiotics (Group C). The cure rate was highest in Group A (93.8%), followed by Group B (90.9%) and Group C (77.8%). Combining Group B and Group C, patients who were treated appropriately demonstrated a higher cute rate (91.3% vs. 75.4%, p = 0.005). Multivariate analysis showed that Group B was more likely to be successfully treated compared to Group C (odds ratio = 2.51, 95% confidence interval = 1.01-6.25, p = 0.047), whereas no difference between Group A and Group B was found (odds ratio = 2.09, 95% confidence interval = 0.20-22.34, p = 0.542, data not shown).

CONCLUSION

Surgical intervention is the definitive therapy for purulent SSTIs. Adjunctive antibiotic therapy increased the cure rate and appropriateness of prescription is influential.

Yeast oropharyngeal colonization in human immunodeficiency virus-infected patients in central taiwan

A prospective, cross-sectional study was conducted at a medical center in central Taiwan to understand the prevalence, associated factors, and microbiologic features for oropharyngeal yeast colonization in human immunodeficiency virus-infected outpatients. Oral yeast colonization was detected in 127 (45 %) patients, including 21 (16.5 %) colonized by more than one species. Of the 154 isolates, Candida albicans was the most common species (114, 74 %), followed by Candida dubliniensis (10, 6.5 %), Candida glabrata (10, 6.5 %), Candida tropicalis (7, 4.5 %), and 13 others. We found that receiving antituberculous drug (p = 0.046) or atazanavir (p = 0.045) was two predictors for patients colonized by non-C. albicans species (p = 0.005) and risking mixed yeast colonization (p = 0.009). Even though our data showed that clinical antifungal drugs remained effective in vitro against the colonizing yeasts, the increased mixed yeast colonization indicates a potential issue for controlling mixed infections in hospital settings.

Autointoxication mechanism ofOryza sativa : III. Effect of temperature on phytotoxin production during rice straw decomposition in soil

The phytotoxicity produced during decomposition of rice straw in soil was evaluated under both constant and changing temperature conditions. Bioassay tests showed that the aqueous extract from a soilstraw mixture after incubation at constant temperature was more than twice as phytotoxic as the extract from soil incubated alone. The phytotoxicity was highest at 20-25 ° C. Temperatures above 25 ° C enhanced rice straw decomposition and also degraded the phytotoxic substances more rapidly. After incubation of soil mixtures under changing temperature regimes in a phytotron, the phytotoxicy of the soil aqueous extracts increased in the following order: soil alone < soil + fertilizer < soil + straw < soil + straw + fertilizer. Growth inhibition of lettuce or rice seedlings was also at the highest at the temperature range of 25-30 ° C irrespective of the direction of temperature changes from either low to high or vice versa. Five phytotoxic phenolics,p-hydroxybenzoic, vanillic,p-coumaric, syringic, and ferulic acids, were obtained from both the aqueous extract and residue of the incubated soil samples and were quantitatively estimated by chromatography. The amount of phytotoxins found in various soil mixtures followed the same increasing order as that found by the seed bioassay test. Although no definite distribution pattern of the phenolics in the incubated soil samples can be attributed to temperature variations, the amount of the phenolics was likely higher in the samples incubated at 25 ° C than at either 15 ° C or 35 ° C. The quantity of toxins released during decomposition of rice straw in soil reached highest levels six weeks after incubation and gradually disappeared after twelve weeks.

Allelopathic dominance ofMiscanthus transmorrisonensis in an alpine grassland community in Taiwan

A study site located at 2600 m elevation in Tartarchia Anpu, Nantou county, Taiwan, exhibits a unique grassland community composed of two principal species,Miscanthus transmorrisonensis andYushinia niitakayamensis, and 35 other species. The relative frequencies of the two species are 12% and 11%, while their relative coverages are 25% and 19.5%, respectively. The values for the remaining 35 species are lower than4% each, while species diversity of the community is -3.04839, indicating great diversity. To elucidate the mechanism of dominance ofM. transmorrisonensis, allelopathic evaluation of the plant was conducted. Aqueous extracts of M.Transmorrisonensis plant parts with two ecotypes were bioassayed. The extracts showed significant phytotoxic effects on seed germination and radicle growth of four tested plants: rye grass, lettuce, and two varieties of Chinese cabbage. In addition, rhizosphere soils underMiscanthus also exhibited significant phytotoxicity, indicating that allelopathic interaction was involved. Some responsible phytotoxic phenolics, namely, p-coumaric, ferulic, vanillic, protocatechuic, o-hydroxyphenylacetic, andm-hydroxyphenylacetic acids, and 4-hydroxycoumarin and phloridzin were identified. Allelopathy thus can play an important role in regulating plant diversity in the field.

Correlation of virulence genes to clinical manifestations and outcome in patients with Streptococcus dysgalactiae subspecies equisimilis bacteremia

BACKGROUND/PURPOSE

Streptococcus dysgalactiae subsp. equisimilis (SDSE) is increasingly recognized as a human pathogen responsible for invasive infection and streptococcal toxic shock syndrome (STSS). The pathogen possesses virulence genes that resemble those found in Streptococcus pyogenes (GAS). We analyzed the association between these specific toxic genes, clinical presentations, and outcome in patients with SDSE infections.

METHODS

Patients (older than 18 years) with community-acquired invasive bacteremia caused by SDSE bacteremia who were undergoing treatment at China Medical University Hospital from June 2007 to December 2010 were included in this study. Multiplex polymerase chain reaction was performed to identify virulence genes of the SDSE isolates. Demographic data, clinical presentations, and outcome in patients with SDSE infections were reviewed and analyzed.

RESULTS

Forty patients with 41 episodes of SDSE bacteremia were reviewed. The median age of the patients with SDSE infection was 69.7 years; 55% were female and 78% had underlying diseases. Malignancy (13, 33%) and diabetes mellitus (13, 33%) were the most common comorbidities. The 30-day mortality rate was 12%. Compared with the survivors, the non-survivors had a higher rate of diabetes mellitus (80% vs. 26%), liver cirrhosis (60% vs.11%), shock (60% vs.17%), STSS (60% vs. 8%), and a high Pittsburgh bacteremia score >4 (40% vs. 6%). Most isolates had scpA, ska, saga, and slo genes, whereas speC, speG, speH, speI, speK, smez, and ssa genes were not detected. speA gene was identified only in one patient with STSS (1/6, 17%). All isolates were susceptible to penicillin, cefotaxime, levofloxacin, moxifloxacin, vancomycin, and linezolid.

CONCLUSION

In invasive SDSE infections, most isolates carry putative virulence genes, such as scpA, ska, saga, and slo. Clinical SDSE isolates in Taiwan remain susceptible to penicillin cefotaxime, and levofloxacin.

Associations between serum total bilirubin levels and functional dependence in the elderly

BACKGROUND

Many studies support the role of bilirubin as a cytoprotector in chronic inflammatory diseases, such as stroke and atherosclerosis.

AIM

To investigate the relationship between serum total bilirubin levels and functional dependence in older adults.

METHODS

Data from the National Health and Nutrition Examination Survey (1999-2002) pertaining to 2235 old adults were analysed. All participants had given a household interview, providing information of five major domains on self-reported functional status (activities of daily living, instrumental activities of daily living, leisure and social activities, lower extremity mobility and general physical activities), had completed serum total bilirubin measurement, and a questionnaire regarding personal health. Poor performance was defined as experiencing difficulty with one or more items in a given domain. Functional dependence was defined as having three or more poor performances in the five major domains. Multiple logistic regression was performed together with quartile-based stratified odds ratio (OR) comparison and trend tests.

RESULTS

The OR of functional dependence for each standard deviation increment in the serum total bilirubin level was 0.56 (P = 0.002). After additional adjustment, the inverse association remained essentially unchanged. In quartile-based analysis, participants with higher quartiles of serum total bilirubin tended to have lower ORs of functional dependence. The trends of lower likelihood of functional dependence across increasing quartiles of the serum total bilirubin level were statistically significant (P < 0.05 for all trends).

CONCLUSIONS

Higher serum total bilirubin levels were associated with lower likelihood of functional dependence in older adults.

Effect of rehabilitation on a patient suffering from a tuberculous brain abscess with Gerstmann's syndrome: case report

There are few reports in the literature of tuberculous brain abscess. Tuberculous brain abscess usually occurs in an immunocompromised host. Almost all previously documented cases have involved acquired immune deficiency syndrome. We encountered a 53-year-old right-handed immunocompetent male who was initially suspected of having a cerebrovascular accident due to acute-onset right hemiparesis and paresthesia. A tentative diagnosis of brain tumor versus brain abscess was made on imaging studies. The patient was finally diagnosed with a tuberculous brain abscess based upon deterioration on imaging and a positive tuberculosis culture. The tuberculous brain abscess was located in the left parietal lobe, which resulted in Gerstmann's syndrome and right-sided apraxia. Stereotactic surgery was performed. He was also given antituberculosis chemotherapy and comprehensive rehabilitation. Considerable improvement was noted after rehabilitation. The patient even returned to a normal life and work. Our case demonstrates that an aggressive intensive inpatient rehabilitation program combined with stereotactic surgery and effective antituberculosis therapy play an important role in improving the outcome for patients with tuberculous brain abscess, Gerstmann's syndrome, and right-sided apraxia.

Infections caused by Gordonia species at a medical centre in Taiwan, 1997 to 2008

The inability of conventional identification systems to accurately identify Gordonia spp. often results in the misdiagnosis of infections by these rare pathogens, which require genomic sequencing for precise identification. In the present study, we describe nine cases of the various types of infection caused by Gordonia spp. From 1997 to 2008, 66 isolates (from 30 patients) initially identified as Rhodoccus spp. by conventional biochemical methods, by the Bacteriology Laboratory of National Taiwan University Hospital, were retrospectively analysed to assess the accuracy of species identification. Fifteen of these isolates (from nine patients) were later found to be Gordonia spp. by two molecular methods: PCR-restriction fragment length polymorphism for heat shock protein gene (hsp65) and the 16S rRNA gene sequencing analysis. Gordonia sputi (n = 8) was the most common species, followed by Gordonia terrae (n = 7). Most of the isolates were isolated from blood (n = 11), followed by soft tissue (n = 2) and eye (n = 2). Five patients presented with bacteraemia and two of these had catheter-related bloodstream infection. Two patients had soft tissue infections and another two patients had infective keratitis and conjunctivitis. The random amplified polymorphic DNA patterns for isolates from different patients were different, indicating that they were genetically unrelated. Accurate identification with molecular methods is required if the role of Gordonia spp. in causing infection is to be recognized.

The chondroprotective effects of ferulic acid on hydrogen peroxide-stimulated chondrocytes: inhibition of hydrogen peroxide-induced pro-inflammatory cytokines and metalloproteinase gene expression at the mRNA level

OBJECTIVE

The objective of the study is to evaluate the effect of ferulic acid (FA), an antioxidant from the Chinese herb Dong-Gui [Chinese angelica, Angelica sinensis (Oliv.) Diels], on the regulation of various genes in hydrogen peroxide-stimulated porcine chondrocytes at the mRNA level.

METHODS

The effect of FA and the effective concentration of FA on porcine chondrocytes was evaluated by the lactate dehydrogenase, WST-1, crystal violet assay, and a chemical luminescence assay. Gene expression in hydrogen peroxide-stimulated chondrocytes either pre- or post-treated with FA was evaluated by real-time PCR.

RESULTS

Chondrocytes pre-treated with 40 microM FA decreased the hydrogen peroxide-induced interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), and MMP-1 and partially restored SOX9 gene expression. Post-treatment with 40 microM FA also decreased the expression of MMP-1 and MMP-13.

CONCLUSION

FA decreased the hydrogen peroxide-induced IL-1beta, TNF-alpha, MMP-1 and MMP-13 and increased SOX9 gene expression. These findings suggest that FA may prove to be important in the treatment of osteoarthritis. Further research is needed.

Genetic manipulation of stationary-phase genes to enhance recombinant protein production in Escherichia coli

Genetic manipulation of the host strain, by which cell physiology could be modulated, was exploited to enhance recombinant protein production in Escherichia coli. The effects of an inactivated stationary-phase gene (rmf or katF) on recombinant protein production in strains with two different expression systems (the pH-inducible and the lac promoters) were investigated. An improvement of recombinant protein production in the katF mutant at low growth rates was observed for both expression systems. A fourfold and a 30% increase in the volumetric recombinant protein activity were observed for the pH-inducible and the lac promoter system, respectively. The effect of the rmf mutation, on the other hand, depends on the expression system. A twofold increase in the volumetric recombinant protein activity was found for the pH-inducible promoter system, but there was no improvement for the lac promoter system. Improvement in culture performance for slow-growing cultures may have an impact on the design strategy of the host/vector system used in fed-batch cultures, where the specific growth rate is usually slow. The information may also be useful for developing optimal host/vector gene expression systems for recombinant protein production.

Patient-driven loop control for ambulation function restoration in a non-invasive functional electrical stimulation system

PURPOSE

In this study, a patient-driven loop control in a non-invasive functional electrical stimulation (FES) system was designed to restore ambulation function of patients with stroke with their residual capabilities.

METHOD

With this patient-driven loop control, patients use the electromyographic (EMG) signals from their voluntary controlled muscles in affected extremity to adjust stimulus parameters of the system. A special designed FES system generated electrical stimuli to excite the paralysed muscles through surface electrodes on the basis of the control command from the residual myoelectric signals. The EMG signals were also served as the trigger and the adjustment of stimulus parameters and thereby adding versatility of the FES system. One patient with hemiplegia was recruited to conduct clinical evaluation and treated by using the new closed-loop FES system.

RESULTS

The experimental results showed that hemiplegic could successfully control the system to restore their lost ambulation functions with the strategy of patient-driven loop control. It is revealed that the mean velocity, cadence, stride length, active ankle motion range and functional ambulation category have improved significantly from 0.22 + or - 0.17 m/s, 37.3 + or - 15.5 steps/min, 0.32 + or - 0.11 m, 10 degrees , level 2 to 0.46 + or - 0.23 m/s, 58.2 + or - 19.1 steps/min, 0.73 + or - 0.22 m, 35 degrees , level 4 respectively for the patient. A paired t-test indicated that differences in the EMG of the tibialis anterior and the gastrocnemius muscles between patient's disabled (affected-side) foot and normal (unaffected-side) foot are not significant (p > 0.05) after 12 weeks of training.

CONCLUSIONS

According to the experiment results, this patient-driven loop control can be beneficial for patient with hemiplegia to restore their ambulation functions such as dorsi-flexion and plantar-flexion. The control strategy of this study has the potential to be employed not only in the FES system but also in other assistive devices.

Diagnostic performance of an enzyme-linked immunospot assay for interferon-gamma in extrapulmonary tuberculosis varies between different sites of disease

OBJECTIVES

To evaluate diagnostic performance of an enzyme-linked immunospot assay for interferon-gamma (T SPOT-TB) in patients with suspected extrapulmonary tuberculosis (TB).

METHODS

From January 2007 to December 2008, patients with suspected extrapulmonary TB were prospectively enrolled from 2 tertiary care hospitals.

RESULTS

A total of 138 patients with suspected extrapulmonary TB were enrolled; 50 patients had positive culture for Mycobacterium tuberculosis and 39 patients had probable TB. The sites of infection were lymph node (n = 20), pleura (n = 19), bone/joint (n = 15), urinary tract (n = 7), peritoneum (n = 7), meninges (n = 6), disseminated (n = 5), intestine (n = 3), pericardium (n = 2), skin (n = 2), throat (n = 1), neck (n = 1), and genitalia (n = 1). The overall sensitivity and specificity were 79.8% (71/89) and 81.6% (40/49). The sensitivity ranged from 100% for tuberculous meningitis, tuberculous pericarditis, and intestinal TB, 95% for lymphadenitis, to 42.9% for tuberculous peritonitis. The sensitivity of the T SPOT-TB assay was 70.6% in immunocompromised patients and 85.5% in immunocompetent patients (p = 0.09).

CONCLUSIONS

The T SPOT-TB assay can be a useful tool for diagnosing extra-pulmonary TB in immunocompetent and immunocompromised patients, particularly for tuberculous meningitis, pericarditis, lymphadenitis, and intestinal TB.

Radiation-enhanced hepatocellular carcinoma cell invasion with MMP-9 expression through PI3K/Akt/NF-kappaB signal transduction pathway

This study is to investigate the molecular mechanism of radiation-enhanced cell invasiveness of hepatocellular carcinoma (HCC) correlating with clinical patients undergoing radiotherapy and subsequently developing metastasis. Three HCC cell lines (HepG2, Hep3B and Huh7) and normal hepatocyte cell line (CL-48) were irradiated with different doses. The effect of radiation on cell invasiveness was determined using the Boyden chamber assay. Radiation-enhanced invasion capability was evident in HCC cells but not in normal hepatocytes. Invasion was observed in gelatin-coated but not fibronectin-coated or type I collagen-coated membranes. Radiation upregulated matrix metalloproteinase-9 (MMP-9) mRNA level, MMP-9 protein level and MMP-9 activity. MMP-9 antisense oligonucleotides inhibited radiation-induced MMP-9 expression and thereby significantly inhibited radiation-induced HCC invasion. Furthermore, phosphatidylinositol 3-kinase (PI3K)/Akt chemical inhibitors LY294002 and wortmannin suppressed radiation-induced MMP-9 mRNA expression. Transient transfection with dominant-negative Akt plasmid also showed that the PI3K/Akt-signaling pathway was involved in this radiation-induced MMP-9 expression. Moreover, nuclear factor-kappaB (NF-kappaB) decoy oligodeoxynucleotide suppressed radiation enhanced MMP-9 promoter activity completely. PI3K/Akt chemical inhibitors inhibited radiation-induced NF-kappaB-driven luciferase promoter activity. Taken together, our results indicated that sublethal dose of radiation could enhance HCC cell invasiveness by MMP-9 expression through the PI3K/Akt/NF-kappaB signal transduction pathway.

Influences of pH and hydraulic retention time on anaerobes converting beer processing wastes into hydrogen

To convert high-solids organic wastes (3% w./w.) to high-value hydrogen, a full factorial experimental design was employed in planning the experiments for learning the effects of pH and hydraulic retention time (HRT) on the hydrogen production in a chemostat reactor using waste yeast obtained from beer processing wastes. For determining which experimental variable settings affect hydrogen production, predictive polynomial quadratic equation and response surface methodology were employed to determine and explain the conditions required for high-value hydrogen production. Experimental results indicate that a maximum hydrogen production rate of 460 mL/gVSS/d was obtained at pH = 5.8 and HRT = 32 hours. Moreover, hydrogenase targeted RT-PCR results indicate that Clostridium thermocellum and Klebsiella pneumoniae predominated.

Noninvasive assessment of spontaneous baroreflex sensitivity and heart rate variability in patients with carotid stenosis

BACKGROUND

Previous limited observations have suggested that atherosclerosis may affect the distensibility of the carotid sinus and then impair the baroreflex sensitivity (BRS). No studies have been done to compare the BRS and heart rate variability (HRV) in patients with carotid stenosis and normal controls.

METHODS

A convenience-consecutive sample of 118 patients with transient ischemic attack or minor stroke 3 months to 1 year before (mean 6 months) who met the study criteria were referred to the neurovascular laboratory of the study hospital. Forty-three age-matched healthy adults were recruited as the normal controls. The inclusion criteria for participation were (1) no diabetes mellitus, (2) no history, symptoms or ECG signs of coronary artery disease or myocardial infarction, and (3) presence of carotid stenosis greater than or equal to 50%. The diagnosis of carotid stenosis was made using color-coded duplex ultrasound with published criteria. We categorized the patients into two groups: group 1 had moderate stenosis (50-75%) and group 2 had high-grade stenosis (75-99%). Instantaneous systolic blood pressure (SBP) and heart rate of all participants were assessed noninvasively using servo-controlled infrared finger plethysmography. The fluctuation in SBP as well as the interpulse interval (IPI) was divided into three components at specific frequency ranges by fast Fourier transform as high frequency (HF; 0.15-0.4 Hz), low frequency (LF; 0.04-0.15 Hz) and very low frequency (VLF; 0.004-0.04 Hz). The BRS was expressed as (1) transfer function with its magnitude in the HF and LF ranges, (2) BRS index alpha, and (3) regression coefficient by sequence analysis. The HRV was expressed as total power and power in the three frequency ranges (HF, LF and VLF).

RESULTS

The final analysis included 99 patients (mean age 72 +/- 6 years, 79 male) and 43 healthy controls (mean age 68 +/- 7 years, 30 male). Forty-three patients were classified as group 1 (stenosis 50-75%) and 56 as group 2 (stenosis 75-99%). There was no significant difference in the IPI between patients and controls (p value = 0.8637). We observed a significant decrease in all three HRV components (VLF, LF and HF) in the patients; however, there were no differences between the two patient groups with various degrees of stenosis. All the indices of BRS, including the magnitude of SBP-IPI transfer function at LF and HF, the computed BRS index alpha and the regression coefficient of sequence analysis, revealed similar results. Patients exhibited a significant reduction in the BRS (p < 0.001) compared with controls, and no difference was found between the two groups of patients.

CONCLUSIONS

Our study linked significant carotid stenosis to two important autonomic markers (BRS and HRV) that may have prognostic value for patients with cardiovascular events. Further prospective studies are needed to explore whether or not the decreased BRS and HRV can be predictors for poor cardiovascular prognosis, or even for shortened life span in general, in patients with significant carotid stenosis.

Peripheral tears of triangular fibrocartilage complex: results of primary repair

In 16 patients with ulnar wrist pain, we performed primary arthroscopic or open repair of the peripheral rim tears of the triangular fibrocartilage complex (TFCC) (14 ulnar, 4 volar, and 3 radial tears). The wrist function was assessed before and 1 year after the repair using the Mayo-modified wrist score. The average pain score improved from 9.1+/-8.0 to 21.2+/-6.5, the average functional score from 5.0+/-8.1 to 20.6+/-6.3, the average motion score from 4.7+/-2.8 to 15.6+/-7.3, and the average grip point from 4.4+/-3.5 to 15.6+/-7.7, all with significant differences (P<0.01). Ten of the 17 cases had instability of the distal radioulnar joint and five had recurrent instability after repair.

Phylogeography of Kandelia candel in East Asiatic mangroves based on nucleotide variation of chloroplast and mitochondrial DNAs

Vivipary with precocious seedlings in mangrove plants was thought to be a hindrance to long-range dispersal. To examine the extent of seedling dispersal across oceans, we investigated the phylogeny and genetic structure among East Asiatic populations of Kandelia candel based on organelle DNAs. In total, three, 28 and seven haplotypes of the chloroplast DNA (cpDNA) atpB-rbcL spacer, cpDNA trnL-trnF spacer, and mitochondrial DNA (mtDNA) internal transcribed spacer (ITS) were identified, respectively, from 202 individuals. Three data sets suggested consistent phylogenies recovering two differentiated lineages corresponding to geographical regions, i.e. northern South-China-Sea + East-China-Sea region and southern South-China-Sea region (Sarawak). Phylogenetically, the Sarawak population was closely related to the Ranong population of western Peninsula Malaysia instead of other South-China-Sea populations, indicating its possible origin from the Indian Ocean Rim. No geographical subdivision was detected within the northern geographical region. An analysis of molecular variance (AMOVA) revealed low levels of genetic differentiation between and within mainland and island populations (phiCT = 0.015, phiSC = 0.037), indicating conspicuous long-distance seedling dispersal across oceans. Significant linkage disequilibrium excluded the possibility of recurrent homoplasious mutations as the major force causing phylogenetic discrepancy between mtDNA and the trnL-trnF spacer within the northern region. Instead, relative ages of alleles contributed to non-random chlorotype-mitotype associations and tree inconsistency. Widespread distribution and random associations (chi2 = 0.822, P = 0.189) of eight hypothetical ancestral cytotypes indicated the panmixis of populations of the northern geographical region as a whole. In contrast, rare and recently evolved alleles were restricted to marginal populations, revealing some preferential directional migration.

Organelle DNA phylogeography of Cycas taitungensis, a relict species in Taiwan

The phylogegraphic pattern of Cycas taitungensis, an endemic species with two remaining populations in Taiwan, was investigated based on genetic variability and phylogeny of the atpB-rbcL noncoding spacer of chloroplast DNA (cpDNA) and the ribosomal DNA (rDNA) internal transcribed spacer (ITS) of mitochondrial DNA (mtDNA). High levels of genetic variation at both organelle loci, due to frequent intramolecular recombination, and low levels of genetic differentiation were detected in the relict gymnosperm. The apportionment of genetic variation within and between populations agreed with a migrant-pool model, which describes a migratory pattern with colonists recruited from a random sample of earlier existing populations. Phylogenies obtained from cpDNA and mtDNA were discordant according to neighbour-joining analyses. In total four chlorotypes (clades I-IV) and five mitotypes (clades A-E) were identified based on minimum spanning networks of each locus. Significant linkage disequilibrium in mitotype-chlorotype associations excluded the possibility of the recurrent homoplasious mutations as the major force causing phylogenetic inconsistency. The most abundant chlorotype I was associated with all mitotypes and the most abundant mitotype C with all chlorotypes; no combinations of rare mitotypes with rare chlorotypes were found. According to nested clade analyses, such nonrandom associations may be ascribed to relative ages among alleles associated with the geological history through which cycads evolved. Nested in networks as interior nodes coupled with wide geographical distribution, the most dominant cytotypes of CI and EI may represent ancestral haplotypes of C. taitungensis with a possible long existence prior to the Pleistocene glacial maximum. In contrast, rare chlorotypes and mitotypes with restricted and patchy distribution may have relatively recent origins. Newly evolved genetic elements of mtDNA, with a low frequency, were likely to be associated with the dominant chlorotype, and vice versa, resulting in the nonrandom mitotype-chlorotype associations. Paraphyly of CI and EI cytotypes, leading to the low level of genetic differentiation between cycad populations, indicated a short period for isolation, which allowed low possibilities of the attainment of coalescence at polymorphic ancestral alleles.

Determination of metformin in human plasma by high-performance liquid chromatography with spectrophotometric detection

A simple, selective, sensitive and precise high-performance liquid chromatographic plasma assay for the hypoglycemic agent metformin is described. Acidified samples of plasma were deproteinated with acetonitrile, washed with dichloromethane and the resulting supernatant injected. Chromatography was performed at 40 degrees C by pumping a mobile phase of acetonitrile (250 ml) in pH 7, 0.03 M diammonium hydrogen phosphate buffer (750 ml) at a flow-rate of 1 ml/min through a silica column. Metformin and the internal standard (atenolol) were detected at 240 nm and were eluted 7.8 and 6.8 min, respectively, after injection. No endogenous substances were found to interfere. Calibration curves were linear (r>0.999) from 10 to 2000 ng/ml. The absolute recovery of both metformin and atenolol was greater than 76%. The detection limit and limit of quantitation were 2.5 and 10 ng/ml, respectively. The intra- and inter-day precision (C.V.) was 12%, or less, and the accuracy was within 6.2% of the nominal concentration. This method is suitable for clinical investigation and monitoring metformin concentration.

The anti-apoptotic role of interleukin-6 in human cervical cancer is mediated by up-regulation of Mcl-1 through a PI 3-K/Akt pathway

Interleukin-6 (IL-6), a multifunctional cytokine, has recently been implicated in human cervical cancer, though the mechanism remains elusive. This study demonstrates that the anti-apoptotic protein Mcl-1 and IL-6 was concomitantly expressed in human cervical cancer tissues and cell lines, but not in normal cervix tissues. Upon IL-6 treatment, Mcl-1, but not other Bcl-2 family members, was rapidly up-regulated peaking at 4-8 h in human cervical cancer C33A cells. Supporting this observation, using anti-IL-6 or anti-IL-6 receptor antibody to interrupt the IL-6 autocrine loop in SiHa cells significantly reduced cellular level of Mcl-1. This study hypothesizes that the expression of Mcl-1 in cervical cancer cells is regulated by IL-6. The matter of which signaling pathways transduced by IL-6 is responsible for the Mcl-1 up-regulation is further investigated herein. Blocking the STAT3 or MAPK pathway with dominant-negative mutant STAT3F or the MEK inhibitor PD98059 failed to inhibit IL-6-mediated Mcl-1 expression. Meanwhile, the IL-6-induced Mcl-1 up-regulation was effectively abolished by treatment with PI 3-K inhibitors, LY294002. Additionally, overexpression of dominant-negative (dn) Akt in C33A cells could inhibit the IL-6-induced increase of Mcl-1. Finally, overexpression of IL-6 in C33A cells caused a markable resistance to apoptosis induced by doxorubicin or cisplatin. Transient transfection of IL-6-overexpressed cells with a mcl-1 antisense vector, leading to the attenuation of their apoptosis-resistant activity. In conclusion, the data herein suggest that IL-6 regulated the mcl-1 expression via a PI 3-K/Akt-dependent pathway that may facilitate the oncogenesis of human cervical cancer by modulating the apoptosis threshold.

Synthesis and properties of novel bis(triarylamines) based on a 3,3'-diphenyl-2,2'-bithiophene core

An efficient synthesis of 3,3'-diphenyl-2,2'-bithiophene based bis(triarylamines) and their physical properties are reported.

Monoterpene glycosides and triterpene acids from Eriobotrya deflexa

A phytochemical study on a methanolic extract of leaves of Eriobotrya deflexa led to the isolation and characterization of nine terpenoid compounds. Four of these are new chemical entities, including two monoterpene glycosides, (3S)-O-alpha-L-rhamnopyranosyl-(1-->3)-[4-O-(E)-coumaroyl]-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranosyl-linalool (1) and (3S)-O-alpha-L-rhamnopyranosyl-(1-->3)-[4-O-(Z)-coumaroyl]-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranosyl-linalool (2), and two triterpene acids, 1beta,2alpha,19alpha-trihydroxy-3-oxo-12-ursen-28-oic acid (3) and 2alpha,3alpha,19alpha-trihydroxy-12-oleanen-28-oic acid (4). Their structures were elucidated on the basis of spectroscopic analysis. The activities of these isolates in an in vitro antiproliferation test were also determined.

Allelopathic prenylflavanones from the fallen leaves of Macaranga tanarius

Two new prenylflavanones, tanariflavanones A (1), and B (2), and one known compound, (-)-nymphaeol-C (3), were isolated from the fallen leaves of Macaranga tanarius. Compounds 1 and 2 showed inhibition of radical growth of lettuce seedlings at 200 ppm. Their structures were elucidated primarily by NMR, circular dichroism, and mass spectroscopic methods.

Apoptosis induced by the antigen receptor and Fas in a variant of the immature B cell line WEHI-231 and in splenic immature B cells

Signaling by the BCR causes proliferation and resistance to Fas-induced apoptosis in mature B cells, but growth arrest and apoptosis in immature B cells. We have identified a variant of the immature B cell line WEHI 231 that retains the apoptotic response to the BCR but has acquired susceptibility to Fas-induced apoptosis. The Fas susceptibility was associated with increased Fas expression on the cell surface and down-regulated IgD expression. These cells exhibited a distinctive functional relationship in response to signals from the BCR, Fas and CD40: BCR stimulation markedly promoted Fas-mediated apoptosis (and vice versa) and Fas-induced apoptosis was not subject to modulation by CD40 signaling. While BCR-induced apoptosis was effectively rescued by CD40, it was not affected by the expression of a dominant-negative FADD. The mechanistic distinctions between BCR- and Fas-induced apoptosis were further characterized by the differential effects of different caspase inhibitors on these two processes which imply the involvement of different subsets of caspases. For BCR-induced apoptosis, we provide evidence that the final apoptotic destruction phase can be inhibited by the pan-caspase inhibitor BOC-Asp-FMK (BD) and that, in the presence of BD, the BCR only induces growth arrest which is reversible. The striking enhancing effects of Fas on BCR-induced apoptosis seen in the variant cells prompted us to examine if a similar cooperation in induction of apoptosis occurs in the highly tolerizable immature B cells of the spleen. We found that the splenic immature B population contains a significant number of Fas-expressing cells, but neither Fas-induced apoptosis nor an enhancing effect of Fas on BCR-induced apoptosis of these cells was detected in vitro.