High rates of colonization and antimicrobial resistance of group B streptococcus highlight the need for vaccination even after implementation of guidelines for intrapartum antibiotic prophylaxis.

INTRODUCTION: It is estimated that about 11-35% of pregnant women are colonized with Group B streptococcus. Intrapartum antibiotic prophylaxis (IAP) is the primary intervention to decrease the risk of infecting babies born to GBS colonized mothers. METHODS: A total of 5,996 pregnant women, who received the Taiwanese universal GBS screening program from 2012 to 2020, were included in this study that investigated GBS colonization, antimicrobial resistance rates and their neonatal incidence of invasive GBS infection. RESULTS: The average GBS colonization rate was 18.5%. Older age groups had higher colonization rates than younger age groups. Compared to Taiwanese, immigrant women from Indonesia had a greater positive rate. GBS isolated from Vietnamese women had significant greater resistance to clindamycin relative to Taiwanese women. Rates of resistance to erythromycin increase from 35.5% to 45.5% over the 9 years of measurements. The incidence of invasive GBS disease was about 0.6/1,000 (4/6,204) live births during the study. CONCLUSIONS: Although relatively low incidence of invasive GBS diseases was observed after implementation of IAP, the colonization of GBS remains high and antimicrobial resistance of GBS is increasing. An effective GBS vaccine holds promise to be a solution for these issues.

High Levels of 25-OH-Vitamin D and Copper in Pregnant Women with Abnormal Glucose Challenge Test.

Several hormones and elements are involved in the homeostasis of glucose metabolism during pregnancy. This present study determined the differences among the factors involved in glucose regulation for pregnant women with and without an abnormal glucose challenge test (GCT), but without gestational diabetes mellitus, during the second trimester of gestation and the postpartum period. One hundred and six pregnant women who had received routine prenatal and postpartum examinations at our hospital were recruited. Sugar-related tests and the levels of pregnancy-associated hormones and 25-OH-vitamin D were performed using a clinical autoanalyzer; six elements were assessed using graphite furnace atomic absorption spectrometry or inductively coupled plasma mass spectrometry. The women in the abnormal GCT group (n = 27) featured significantly higher levels of 25-OH-vitamin D (p = 0.006) and copper (p < 0.001) than those in the normal GCT group (n = 79). After adjusting for possible pregnancy factors, abnormal GCT remained the significant contributing factor for the elevated levels of 25-OH-vitamin D and copper during gestation (p = 0.046 and 0.002, respectively). Furthermore, significant positive correlations existed between 25-OH-vitamin D and glucose after a 50-g GCT (p = 0.001), 25-OH-vitamin D and HbA1C (p = 0.004), serum copper and glucose after a 50-g GCT (p = 0.003), and serum copper and HbA1C (p < 0.001). We conclude that blood 25-OH-vitamin D and copper are strongly correlated with glucose levels during gestation; these two factors are potential clinical predictors for maternal impaired glucose tolerance and, indirectly, for reducing perinatal risks and neonatal complications.

Magnesium, zinc, and chromium levels in children, adolescents, and young adults with type 1 diabetes.

BACKGROUND & AIMS: Several trace elements are involved in insulin signal transduction and glucose metabolism. Our aim for this present study was to determine the levels of three important elements-magnesium, chromium, and zinc-as well as one oxidative stress marker-malondialdehyde (MDA)-in young type 1 diabetic patients at different periods of their growth, and to realize the relationships between trace elements, oxidative stress, and growth stages. METHODS: A total of 88 patients with type 1 diabetes mellitus in different growth stages and 76 gender- and age-matched healthy subjects were included in this study. The levels of MDA were measured through HPLC using a C-18 column. Zinc, magnesium, and chromium concentrations in serum were assessed using atomic absorption spectrophotometry. RESULTS: We found higher levels of blood malondialdehyde (MDA; p < 0.001), significantly lower levels of magnesium (p < 0.001), and no differences in zinc and chromium levels (p = 0.153 and 0.515, respectively) in younger type 1 diabetic subjects relative to those of control subjects. Only 3.4% (3/88) of younger diabetic subjects exhibited hypomagnesemia; similar results were obtained when comparing different subgroups: children, adolescents, and adults. We also observed no differences in the levels of the three elements between the genders and among the growth stages (p > 0.05) of the diabetic subjects. There were no correlations between the three trace elements and HbA1C, diabetes duration, and insulin dose/BMI (all p > 0.05), but there was a significant difference between zinc levels and insulin dose/BMI (p = 0.043) in the diabetic patients. CONCLUSIONS: We found elevated blood MDA, decreased magnesium, and no changes in zinc and chromium levels in younger type 1 diabetic subjects relative to those of control subjects. Only 3.4% of younger diabetic subjects exhibited hypomagnesemia. Whether magnesium supplementation is suitable for improving insulin sensitivity and decreasing oxidative stress and inflammation will require confirmation through additional studies.

Selective and eco-friendly method for determination of mercury(II) ions in aqueous samples using an on-line AuNPs-PDMS composite microfluidic device/ICP-MS system.

In this study we developed an on-line, eco-friendly, and highly selective method using a gold nanoparticle (AuNP)-coated polydimethylsiloxane (PDMS) composite microfluidic (MF) chip coupled to inductively coupled plasma mass spectrometry (ICP-MS) to separate trace Hg(2+) ions from aqueous samples. Because Hg(2+) ions interact with AuNPs to form Hg-Au complexes, we were able to separate Hg(2+) ions from aqueous samples. We prepared the AuNPs-PDMS composite through in situ synthesis using a PDMS cross-linking agent to both reduce and embed AuNPs onto PDMS microchannels so that no additional reductants were required for either AuNP synthesis or the PDMS surface modification (2% HAuCl4, room temperature, 48 h). To optimize the proposed on-line system, we investigated several factors that influenced the separation of Hg(2+) ions in the AuNPs-PDMS/MF, including adsorption pH, adsorption and elution flow rates, microchannel length, and interferences from coexisting ions. Under optimized conditions (pH 6.0; adsorption/elution flow rates: 0.05/0.5 mL min(-1); channel length: 840 mm), we evaluated the accuracy of the system using a standard addition method; the measured values had agreements of ≥ 93.0% with certified values obtained for Hg(2+) ions. The relative standard deviations of the proposed method ranged from 2.24% to 6.21%. The limit of detection for Hg(2+) for the proposed on-line AuNPs-PDMS/MF/ICP-MS analytical method was as low as 0.07 µg L(-1).

On-line microdialysis coupled with liquid chromatography for biomedical analysis.

This work presents a review of the microdialysis (MD) sampling technique for on-line coupling with high-performance liquid chromatography (HPLC) for biomedical analysis. MD-HPLC was first used in the field of brain metabolism to study neurotransmission, and this remains its common application in the biomedical field. On-line MD-HPLC hyphenated methods provide advantages over those with off-line MD-based techniques, including simplified sample preparation, automated analyses, avoidance of contamination introduced during the analytical process, and in situ analysis of the extracellular fluid of living organisms. This review outlines the effectiveness of the continuous monitoring of unbound chemicals from tissues, organs, and body fluids by on-line MD-HPLC methods. In addition, a discussion is presented on the application of in vivo on-line MD-HPLC toward obtaining biochemical event information in the extracellular fluid of various tissues and in biological fluids for pharmacokinetic, pharmacodynamic, toxicological, and bioprocess monitoring.

On-line microdialysis-nano-Au/TiO2-high-performance liquid chromatography system for the simultaneous determination of cobalt and nickel in water.

An on-line configuration of microdialysis (MD), Au/TiO2 nanoparticle preconcentration, and high-performance liquid chromatography-ultraviolet (HPLC-UV) detection method was developed for the simultaneous measurement of cobalt (Co) and nickel (Ni) concentrations in water. The sample matrix was first cleaned with an MD system using a MD probe. A continuously flowing dialysate stream was introduced into tubing coated with Au/TiO2 nanoparticles to adsorb metals, followed by elution by an acidic eluent. The enriched samples were derivatized on-line using 8-hydroxyquinoline. The separation of Co and Ni were achieved by using a LC-C18 column. The three aforementioned system components were connected on-line using a valve control. The UV detection was performed at 319nm. Validation experiments demonstrate good linearity, precision, accuracy, and recovery. The proposed method offers a simple and reliable procedure to determine the levels of Co and Ni in environmental water samples. Moreover, the methodology described in this study adheres to the concept of green chemistry, including the absence of organic solvents in the MD sampling and extraction processes. To the best of our knowledge, the proposed method is the first reported on-line connection of MD, Au/TiO2 nanoparticle tubing, and HPLC devices for the measurement of Co and Ni concentrations in water.

Real-time dynamic monitoring of nonprotein-bound copper in the blood.

To obtain real-time dynamic changes of non-protein-bound copper in the blood, we have developed an online microdialysis sampling system coupled with a flow-injection graphite furnace-atomic absorption spectrometer (FI-GFAAS). The analytical performances of the online system such as linearity, limit of detection, precision, and spiked recoveries were validated. Before the in vivo experiments, the in vivo recovery was conducted. The levels of non-protein-bound Cu in the blood of living rabbits were evaluated before and after administering them with 5 mg/kg body weight of CuSO4 by the online microdialysis-FI-GFAAS system. The results showed that the average basal concentration of non-protein-bound Cu in the blood of living rabbits was 16.2 microg/L (n = 3). Furthermore, the levels of non-protein-bound Cu in the blood of living rabbits were observed after a long delay following intravenous injection of CuSO4. The non-protein-bound Cu reached the maximum value at 125 min after injection. Our present study might provide the in vivo, direct observation that different metals have their own binding characteristics with proteins when transported into the blood of living organisms.

Continuous in vivo monitoring of blood diffusible calcium using on-line microdialysis sampling coupled with flame atomic absorption spectrometry.

A direct, rapid and continuous in vivo monitoring of diffusible calcium in the blood of living rabbits has been developed using microdialysis sampling coupled on-line with flame atomic absorption spectrometry. Microdialysates perfused through implanted microdialysis probes were collected with a sample loop on an injection valve and directly introduced into the flame atomizer by a carrier solution. An ultrapure saline solution (0.9% NaCI, pH 7.2) was used as the perfusion solution at a flow rate of 20 microI min(-1) via the microdialysis probe. A 0.1% La solution in 0.5% HNO3 solution was employed as the carrier solution at a nebulizer uptake flow rate of 2.5 ml min(-1). The interval for each determination was 2.5 min (2 min of sampling time, 20 s of read time and 10 s of washing time). The performance characteristics of the on-line microdialysis-FAAS system were validated as follows: linearity range, 0 - 100 mg l(-1); detection limit (3a, n = 7), 3.66 mg l(-1); precision (RSD, n = 50), 6.2%. For the evaluation of analytical accuracy, the proposed on-line method was compared with the in vivo no net flux method. The use of an on-line microdialysis-FAAS system permitted the in situ, dynamic and continuous in vivo monitoring of diffusible calcium in the blood of the living rabbits after CaCl2 administration with a temporal resolution of 2.5 min.

On-line microdialysis sampling coupled with flame atomic absorption spectrometry for continuous in vivo monitoring of diffusible magnesium in the blood of living animals.

A novel on-line microdialysis sampling coupled with flame atomic absorption spectrometry (FAAS) with an attractive application is reported. Microdialysates perfused through implanted microdialysis probes were directly introduced into the flame atomizer of a FAAS system using 0.2% HNO(3) as carrier solution at a nebulizer uptake flow rate of 6mlmin(-1). The interval for each determination was 90s (60s sampling time, 10s read time and 20s washing time). The analytical characteristics of the on-line microdialysis-FAAS system were validated as follows: linearity range, 0-300mgl(-1); detection limit (3sigma, n=7), 0.53mgl(-1); precision (R.S.D., n=50), 4.1%. By comparing Mg levels in the blood of living rabbits with the results obtained from in vivo no net flux (NNF) method, the accuracy of the proposed on-line method was found to be good. The present method can be successfully applied to the in vivo monitoring of diffusible Mg in the blood of living rabbits after magnesium sulfate (MgSO(4)) administration with a temporal resolution of 1.5min.