Performance enhancement of procalcitonin by high-sensitivity C-reactive protein at the optimal cutoff in predicting bacteremia in emergency department adult patients.

Pathogenic bacteremia portends a high mortality risk in adult patients admitted to an Emergency Department (ED). This study aims to investigate the effect of adding high-sensitivity C-reactive protein (hs-CRP) to procalcitonin (PCT) and lactate in predicting bacteremia, Gram-negative (GNB) and Gram-positive bacteremia (GPB), using the optimal cutoff derived from the receiver operating characteristics analysis. We evaluated the diagnostic measures, including the positive-test likelihood (LR+), the negative-test likelihood (LR-), and the diagnostic odds ratio (DOR) using a single-center retrospective analysis design. This Standards for Reporting Diagnostic-compliant study comprised 886 consecutive adults who were admitted to the ED in 2010; to this cohort, a 22.2% prevalence of true bacteremia was subsequently confirmed. At the cutoff of 3.9 µg/L, PCT had a DOR of 5.3 (95% confidence interval [CI]: 3.76-7.61) and LR + of 2.8 (95% CI: 2.3-3.4) in predicting overall bacteremia. Elevated PCT and lactate (cutoff at 2 mmol/L), increased the DOR and LR + to 6.3 (95% CI: 4.27-9.29) and 4.0 (95% CI: 3.1-5.2). The DOR and LR + were further improved to 7.1 (95% CI: 4.2-11.95) and 5.6 (95% CI: 3.7-8.6), respectively, when hs-CRP at the cutoff of 1238 nmol/L was added to PCT plus lactate. High-sensitivity CRP at the cutoff of 1,255 nmol/L can enhance the discriminative power raising DOR and LR + values for GPB. The elevation of hs-CRP at the optimal cutoff might improve the diagnostic performance to predict unspecified bacteremia and GPB, but not GNB.

Proteomic analysis of chondrocytes exposed to pressure.

Chondrocytes are the only cell type present in mature articular cartilage (2-5% of total tissue). The biological activities of the chondrocyte population are regulated by genetic, biologic and biochemical factors, as well as environmental factors (stress, flow and electric field). Although compressive forces within joint articular cartilage are required for maintenance of the normal composition of articular cartilage, there is a lack of knowledge about the number of pressure-related proteins expressed in articular cartilage. Two-dimensional gel electrophoresis (2-DE) and high-performance liquid chromatography-electrospray/tandem mass spectrometry (HPLC/ESI-MS/MS) were used to identify the levels of pressure-related proteins expressed by chondrocytes grown in the presence or absence of hydrostatic pressure. A total of 266 spots were excised from the gels and analyzed by HPLC/ESI-MS/MS. Functional classification of up-regulated proteins indicated that energy and protein fate were the main biological processes occurring in pressurized chondrocytes. Furthermore, membrane-bound transferrin-like protein p97, a marker of chondrocyte differentiation, was only expressed in chondrocytes under hydrostatic pressure. These data suggest that hydrostatic pressure can induce cell differentiation by increasing the expression level of energy metabolism- and protein fate-related proteins, indicating that hydrostatic pressure may be needed for normal biosynthesis and differentiation of articular chondrocytes.

Analysis of urinary nucleosides as helper tumor markers in hepatocellular carcinoma diagnosis.

Hepatocellular carcinoma (HCC) is a common neoplasm in Taiwan, for which early diagnosis is difficult and the prognosis is usually poor. HCC is usually diagnosed by abdominal sonography and serum alpha-fetoprotein (AFP) detection. Modified nucleosides, regarded as indicators for the whole-body turnover of RNAs, are excreted in abnormal amounts in the urine of patients with malignancies and can serve as tumor markers. We analyzed the excretion patterns of urinary nucleosides from 25 HCC patients and 20 healthy volunteers by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC/ESI-MS/MS) under optimized conditions. The HPLC/ESI-MS/MS approach with selective reaction monitoring (SRM) allowed for the sensitive determination of nucleosides in human urine samples. The mean levels of the urinary nucleosides adenosine, cytidine, and inosine were significantly higher in HCC patients than healthy volunteers (average of 1.78-, 2.26-, and 1.47-fold, respectively). However, the mean levels of urinary 1-methyladenosine, 3-methylcytidine, uridine, and 2'-deoxyguanosine were not significantly different. Combined with the determination of serum AFP levels, the higher levels of urinary adenosine, cytidine, and inosine may be additional diagnosis markers for HCC in Taiwanese patients.

Diagnostic value of serum procalcitonin, lactate, and high-sensitivity C-reactive protein for predicting bacteremia in adult patients in the emergency department.

BACKGROUND: Few studies compared the diagnostic value of procalcitonin with a combination of other tests including lactate and high-sensitivity C-reactive protein in the prediction of pathogenic bacteremia in emergency department adult patients. METHODS: We performed a retrospective study assessing the differences in performances of procalcitonin at a cutoff of 0.5 ng/mL, lactate at a cutoff of 19.8 mg/dL, high-sensitivity C-reactive protein at a cutoff of 0.8 mg/dL and their combinations for predicting bacteremia in emergency department adult patients. Sensitivity, specificity, overall accuracy, positive-test and negative-test likelihood, and diagnostic odds ratio with 95% confidence interval for each test combination were calculated for comparison. The receiver operating characteristic curve for every single test were compared using DeLong's method. We also performed a sensitivity analysis in two expanded patient cohorts to assess the discriminative ability of procalcitonin or test combination. RESULTS: A total of 886 patients formed the initial patient cohort. The area under the receiver operating characteristic curve for discriminating positive blood culture was: procalcitonin = 0.72 (95% CI [0.69-0.75]) with a derived optimal cutoff at 3.9 ng/mL; lactate 0.69 (0.66-0.72) with an optimal cutoff at 17.9 mg/dL; high-sensitivity C-reactive protein 0.56 (0.53-0.59) with an optimal cutoff of 13 mg/dL; with pairwise comparisons showing statistically significant better performance of either procalcitonin or lactate outperforming high-sensitivity C-reactive protein. To predict positive blood cultures, the diagnostic odds ratio for procalcitonin was 3.64 (95% CI [2.46-5.51]), lactate 2.93 (2.09-4.14), and high-sensitivity C-reactive protein 0.91 (0.55-1.55; P = 0.79). About combined tests, the diagnostic odds ratio for procalcitonin and lactate increases were 3.98 (95% CI [2.81-5.63]) for positive blood culture prediction. Elevated procalcitonin level rendered a six-fold increased risk of positive gram-negative bacteremia with a diagnostic odds ratio of 6.44 (95% CI [3.65-12.15]), which showed no further improvement in any test combinations. In the sensitivity analysis, as a single test to predict unspecified, gram-negative and gram-positive bacteremia, procalcitonin performed even better in an expanded cohort of 2,234 adult patients in terms of the diagnostic odds ratio. DISCUSSIONS: For adult emergency patients, procalcitonin has an acceptable discriminative ability for bacterial blood culture and a better discriminative ability for gram-negative bacteremia when compared with lactate and high-sensitivity C-reactive protein. High-sensitivity C-reactive protein at a cutoff of 0.8 mg/dL performed poorly for the prediction of positive bacterial culture.

Urinary cytidine as an adjunct biomarker to improve the diagnostic ratio for gastric cancer in Taiwanese patients.

BACKGROUND: Gastric cancer is a major public health concern as the fourth most common cancer, and it is of particular relevance as the second most common cause of cancer death worldwide. We caparisoned the urinary nucleoside concentrations between the gastric patients and healthy volunteers that try to evaluate the diagnostic value in the gastric cancer. METHOD: Urinary nucleosides from 49 gastric patients and 40 healthy volunteers were evaluated by high-performance liquid chromatography/electrospray ionization-tandem mass spectrometry (HPLC/ESI-MS/MS) under optimized conditions as determined in our previous study. RESULTS: The mean concentrations of 5 urinary nucleosides, cytidine, 3-methylcytidine (m3C), 1-methyladenosine (m1A), adenosine, and inosine, were found to be elevated in cancer patients, but only cytidine showed a significant elevation. Moreover, cytidine concentrations were significantly elevated by an average of 1.42-fold in patients with late stage (S3+4) disease. Combining the determined concentrations of preoperative serum alpha-fetoprotein (AFP, cutoff of 20 µg/l) or carbohydrate antigen 19-9 (CA19-9, cutoff of 37 U/ml) with the mean urinary cytidine concentration was shown to improve the diagnostic ratio (sensitivity) for gastric cancer from 16.3% (8/49 patients) to 38.8% (8+11/49 patients) or from 28.6% (14/49 patients) to 51.0% (14+11/49 patients), respectively. CONCLUSIONS: Urinary cytidine may be an important adjunct biomarker for gastric cancer.

Analysis of urinary nucleosides as potential tumor markers in human breast cancer by high performance liquid chromatography/electrospray ionization tandem mass spectrometry.

BACKGROUND: Breast cancer is the most common female cancer and the fourth leading cause of cancer death among women in Taiwan. We measured urinary nucleoside levels in female breast cancer patients (n=36) to evaluate the diagnostic value of nucleosides as potential tumor markers. METHODS: Purification of urinary nucleosides was performed using a 96-well solid phase extraction (SPE, cation-exchange column) procedure to decrease the variation between the single column preparations and to shorten the pretreatment time. Cation-exchange allows for the comprehensive purification of modified nucleosides, such as 2-deoxynucleosides, that are not purifiable by phenylboronic acid-based SPE. High-performance liquid chromatography (HPLC) coupled with mass spectrometry (MS) in selected reaction monitoring (SRM) mode was used to quantify multiple nucleosides. Tubercidin was used as an internal standard. The qualitative parameters, retention time, and the parent and daughter ions used revealed that the method was more specific and sensitive than traditional UV detection. RESULTS: Urinary levels of 3 nucleosides, cytidine, 3-methylcytidine, and inosine were significantly higher in breast cancer patients than in normal controls (p<0.01). The discriminative powers of cytidine, 3-methylcytidine, and inosine were 58%, 58%, and 62%, respectively. CONCLUSIONS: LC/MS/MS is a highly specific and sensitive method for rapidly screening a large number of urinary nucleosides that may be potential cancer markers. The 3-methylcytidine may be a candidate marker for breast cancer.

Nosocomial outbreak of infection with multidrug-resistant Acinetobacter baumannii in a medical center in Taiwan.

OBJECTIVE: To investigate a nosocomial outbreak of infection with multidrug-resistant (MDR) Acinetobacter baumannii in the intensive care units at China Medical University Hospital in Taiwan. DESIGN: Prospective outbreak investigation. SETTING: Three intensive care units in a 2,000-bed university hospital in Taichung, Taiwan. METHODS: Thirty-eight stable patients in 3 intensive care units, all of whom had undergone an invasive procedure, were enrolled in our study. Ninety-four A. baumannii strains were isolated from the patients or the environment in the 3 intensive care units, during the period from January 1 through December 31, 2006. We characterized A. baumannii isolates by use of repetitive extragenic palindromic-polymerase chain reaction (REP-PCR) and random amplified polymorphic DNA (RAPD) fingerprinting. The clinical characteristics of the source patients and the environment were noted. RESULTS: All of the clinical isolates were determined to belong to the same epidemic strain of MDR A. baumannii by the use of antimicrobial susceptibility tests, REP-PCR, and RAPD fingerprinting. All patients involved in the infection outbreak had undergone an invasive procedure. The outbreak strain was also isolated from the environment and the equipment in the intensive care units. Moreover, an environmental survey of one of the intensive care units found that both the patients and the environment harbored the same outbreak strain. CONCLUSION: The outbreak strain of A. baumannii might have been transmitted among medical staff and administration equipment. Routine and aggressive environmental and equipment disinfection is essential for preventing recurrent outbreaks of nosocomial infection with MDR A. baumannii.