Turbidimetric flow analysis system for the investigation of microbial growth

The monitoring of life of microbial populations is of the uttermost importance in environmental and food analysis, agriculture, as well as in medicine. The duration of bacteria adaptation to new environmental conditions, its lifetime and the divisions' pace are the key information in many studies. It was found that the fully-mechanized flow analysis system based on solenoid valves and pumps, paired with a dedicated flow-through optoelectronic detector can be successfully applied for monitoring of bacteria growth. The applicability of the designed multicommutated flow analysis (MCFA) system was proved by analysis of solutions containing bacteria cells proceeded by tests of McFarland (McF) standards. The developed setup allowed modelling and simulation of microbial growth, as well as monitoring of the bacteria growth in real-time manner to be carried out. The monitor is useful for the quantitative estimation of the basic parameters of bacteria population like its size, the rate of bacteria multiplication, as well as the times of lag, log and stationary phases of microbial growth.

Therapeutic drug monitoring of mycophenolic acid (MPA) using volumetric absorptive microsampling (VAMS) in pediatric renal transplant recipients: ultra-high-performance liquid chromatography-tandem mass spectrometry analytical method development, cross-validation, and clinical application

BACKGROUND

Mycophenolic acid (MPA) is widely used in posttransplant pharmacotherapy for pediatric patients after renal transplantation. Volumetric absorptive microsampling (VAMS) is a recent approach for sample collection, particularly during therapeutic drug monitoring (TDM). The recommended matrix for MPA determination is plasma (PL), and conversion between capillary-blood VAMS samples and PL concentrations is required for the appropriate interpretation of the results.

METHODS

This study aimed to validate and develop a UHPLC-MS/MS method for MPA quantification in whole blood (WB), PL, and VAMS samples, with cross and clinical validation based on regression calculations. Methods were validated in the 0.10-15 µg/mL range for trough MPA concentration measurement according to the European Medicines Agency (EMA) guidelines. Fifty pediatric patients treated with MPA after renal transplantation were included in this study. PL and WB samples were obtained via venipuncture, whereas VAMS samples were collected after the fingerstick. The conversion from VAMS_MPA to PL_MPA concentration was performed using formulas based on hematocrit values and a regression model.

RESULTS

LC-MS/MS methods were successfully developed and validated according to EMA guidelines. The cross-correlation between the methods was evaluated using Passing-Bablok regression, Bland-Altman bias plots, and predictive performance calculations. Clinical validation of the developed method was successfully performed, and the formula based on regression was successfully validated for VAMS_MPA to PL_MPA concentration and confirmed on an independent group of samples.

CONCLUSIONS

This study is the first development of a triple matrix-based LC-MS/MS method for MPA determination in the pediatric population after renal transplantation. For the first time, the developed methods were cross-validated with routinely used HPLC-DAD protocol.

The relationship between 6-thioguanine levels and remission outcomes in children with autoimmune hepatitis. Single center experience

Aim of the study

The treatment of autoimmune hepatitis (AIH) is based on steroids and azathioprine (AZA). AZA is a pro-drug which is converted among others into 6-thioguanine (6-TG) and 6-methylmercaptopurine (6-MMP). The aim of the study was to determine the relationship between the AZA active metabolite 6-TG and both the biochemical and histological remission outcomes.

Material and methods

The authors conducted a retrospective analysis of a single chart review. The sample size consisted of 44 pediatric patients with AIH. Biochemical remission was defined as an alanine aminotransferase (ALT) level below 40 U/l and histological remission was defined as a situation when the control biopsy revealed inflammation grade G1 (or lower) in the Batts-Ludwig score. Statistical analysis was applied to assess the difference in remission outcomes in patients with different levels of 6-TG.

Results

In the benchmark variant of our statistical analysis, we found that the correlation between 6-TG and ALT in the sample was not statistically significant. Moreover, the difference between the mean levels of ALT in the populations in and without remission was not statistically significant (the p-value of the t-test was 0.16).

Conclusions

Our results tend to support the claim that there is no statistically significant relationship between 6-TG concentration and remission (both biochemical and histological) in pediatric patients with AIH.

Therapeutic Drug Monitoring of Tacrolimus Based on Volumetric Absorptive Microsampling Technique (VAMS) in Renal Transplant Pediatric Recipients-LC-MS/MS Method Development, Hematocrit Effect Evaluation, and Clinical Application

Tacrolimus (TAC) is post-transplant pharmacotherapy's most widely used immunosuppressant. In routine clinical practice, frequent uncomfortable venipuncture is necessary for whole-blood (WB) collection to check trough TAC levels. Volumetric absorptive microsampling (VAMS) is an alternative strategy to WB collection. In this study, we aimed to validate and develop a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for TAC quantification in WB and VAMS samples. After extraction with water and protein precipitation, the samples were directly analyzed using LC-MS/MS. Whole-blood and VAMS capillary-blood samples were collected from 50 patients treated with TAC during the follow-up visits. The cross-correlation between the developed methods was evaluated using Passing-Bablok regression and a Bland-Altman bias plot. The matrix effect (ME) and carry-over were insignificant for both scenarios. There was a high correlation between the processes and no significant clinical deviation. LC-MS/MS methods were successfully developed and validated in the 0.5-60 ng/mL calibration range. This study demonstrated and confirmed the utility of VAMS-based TAC monitoring in the pediatric population. This is the first study to directly develop and validate the VAMS LC-MS/MS method for evaluating the hematocrit effect in the pediatric population. The statistical correlation between immunochemical and VAMS-based methods was satisfactory.

Cefazolin prophylaxis in children undergoing cardiac surgery with the use of cardiopulmonary bypass-is the dosing correct?

OBJECTIVES

To determine the recommended concentrations of cefazolin to be used for antibiotic prophylaxis during paediatric cardiac surgery with extracorporeal circulation (ECC).

METHODS

Twenty paediatric patients undergoing cardiac surgery with ECC and cefazolin antibiotic prophylaxis were included in the study. Blood samples for measurement of total cefazolin plasma concentration were collected at the following measurement time points: directly after skin incision, 15 min after ECC start, 5 min after ECC cessation and at skin closure. The target concentration was set for ≥40 mg/l, which corresponded to ≥8 mg/l of unbound cefazolin concentration.

RESULTS

The median total cefazolin plasma concentrations at the measurement time points were 62.8, 67.7, 45.8 and 34.2 mg/l, respectively, and target concentrations were achieved in 90%, 85%, 65% and 40% of children, respectively. Among patients who received ≥30 mg of cefazolin per 100 ml of ECC priming, target concentrations after ECC cessation were reached in 80% of patients, while in those with <30 mg cefazolin per 100 ml in 20% of patients (P = 0.031).

CONCLUSIONS

Direct extrapolation of antibiotic prophylaxis recommendations from adults to children may result in suboptimal antibiotic concentrations. An additional cefazolin dose to ECC priming appears necessary and the dosing should be based on ECC priming volume rather than on the weight of the patient.

Serum levels of n-3 and n-6 polyunsaturated fatty acids in patients with systemic lupus erythematosus and their association with disease activity: a pilot study

Objective: Polyunsaturated fatty acids (PUFAs) may modulate the inflammatory process in systemic autoimmune diseases, including systemic lupus erythematosus (SLE). The aim of this study was to assess the serum concentrations of essential 18-carbon PUFAs and their long-chain derivatives in patients with SLE and healthy controls, and to analyse their associations with laboratory and clinical features of the disease.Method: n-6 and n-3 PUFA composition was assessed in the sera of 30 SLE patients and 20 healthy controls using gas chromatography-mass spectrometry. We investigated the associations between PUFAs and disease activity measured with Systemic Lupus Erythematosus Activity Index (SLEDAI) scores, erythrocyte sedimentation rate, C-reactive protein, complement C3 and C4 concentrations, anti-nuclear antibody (ANA) titre, anti-double-stranded DNA (anti-dsDNA) antibody concentration, and medications.Results: Serum linoleic acid (LA) and α-linolenic acid concentrations were significantly higher in SLE patients compared with healthy controls. LA concentration correlated positively with the ANA titre and corticosteroid doses; eicosapentaenoic acid (EPA) and docosahexaenoic acid correlated inversely with anti-dsDNA antibody concentration. Patients treated with immunosuppressants had significantly lower concentrations of LA, arachidonic acid, and EPA.Conclusion: Both n-6 and n-3 PUFA precursors can participate in the inflammatory process in SLE patients. The mechanism of the PUFA metabolism disturbance needs further exploration.

The comparison between light-scattering detectors based on LED and photodiode for immunoprecipitation assays of transferrin and ferritin

Undoubtedly, light-emitting diodes (LEDs) and photodiodes (PDs) are indispensable optoelectronic devices in modern analytical chemistry. LEDs can serve as either light emitters or detectors, thus being an alternative to the most popular detection systems consisted of PD. In this contribution, a comparison between LED-LED and LED-PD detectors, operating in turbidimetric and nephelometric modes, has been carried out for immunoprecipitation detection of transferrin and ferritin. The greatest emphasis was placed on the study of detectors responses under different measurement conditions including current powering an emitter, amplification gain in the case of PD as detector or the construction of detection cells designed for the Multicommutated Flow Analysis (MCFA). The assumption was to obtain the fully-mechanized system with simple but efficient detection system to enable the determination of iron-binding proteins occurring at different concentration ranges in human body. As a result, the optimized arrangements of LED-LED and LED-PD setups were characterized by similar analytical characteristics, enabling the determination of transferrin with the detection limit (LOD) of 0.2 mg/L and RSDs of 2.8-4.8% for LED-LED, and LOD of 0.1 mg/L and RSDs of 0.9-3.6% for LED-PD. In the case of ferritin detection, only the response of the LED-PD detector was statistically distinguishable in the range of 130-198 μg/L of protein with recorded analytical signal change of 20 mV value. The addition of polymer for signal enhancement provided the increase of response range to 107-253 μg/L, enabling the developed system for detection of pathological serum ferritin levels.

Gut microbiota and its metabolic potential

OBJECTIVE

The incidence of obesity and other metabolic-related diseases has been gradually increasing. Multiple genetic as well as environmental factors play a significant role in the pathogenesis of these entities. Currently, the involvement of gut microbiota in metabolic processes has been acknowledged. This paper focuses on obesity, type 2 diabetes, and nonalcoholic fatty liver disease regarding their link with microbiome structure and its function.

MATERIALS AND METHODS

We analyzed literature available in PubMed, Embase, and Google Scholar databases regarding a linkage of metabolic-associated diseases and gut microbiota RESULTS: Gut microbiota plays a significant role in host metabolism. Depending on its composition; however, it may contribute to the development of metabolic-associated diseases. In this context, not only composition of gut microbiota is important, but also its activity. Short-chain fatty acids or lipopolysaccharides are crucial metabolites involved in maintaining metabolic balance.

CONCLUSIONS

Gut microbiota malfunctions might potentially induce obesity, type 2 diabetes, and nonalcoholic fatty liver disease.

High intensity interval and moderate continuous cycle training in a physical education programme improves health-related fitness in young females

The aim of the study was to investigate the effects of eight weeks of regular physical education classes supplemented with high intensity interval cycle exercise (HIIE) or continuous cycle exercises of moderate intensity (CME). Forty-eight collegiate females exercising in two regular physical education classes per week were randomly assigned to two programmes (HIIE; n = 24 or CME; n = 24) of additional (one session of 63 minutes per week) physical activity for 8 weeks. Participants performed HIIE comprising 2 series of 6x10 s sprinting with maximal pedalling cadence and active recovery pedalling with intensity 65%–75% HR_max or performed CME corresponding to 65%-75% HR_max. Before and after the 8-week programmes, anthropometric data and aero- and anaerobic capacity were measured. Two-way ANOVA revealed a significant time main effect for VO₂max (p < 0.001), similar improvements being found in both groups (+12% in HIIE and +11% in CME), despite body mass not changing significantly (p = 0.59; +0.4% in HIIE and -0.1% in CME). A significant main time effect was found for relative fat mass (FM) and fat-free mass (FFM) (p < 0.001 and p < 0.001, respectively). A group x time interaction effect was found for relative FM and FFM (p = 0.018 and p = 0.018); a greater reduction in FM and greater increase in FFM were noted in the CME than the HIIE group. Improvements in anaerobic power were observed in both groups (p < 0.001), but it was greater in the HIIE group (interaction effect, p = 0.022). Weight loss is not mandatory for exercise-induced effects on improving aerobic and anaerobic capacity in collegiate females. Eight weeks of regular physical education classes supplemented with CME sessions are more effective in improving body composition than physical education classes supplemented with HIIE sessions. In contrast to earlier, smaller trials, similar improvements in aerobic capacity were observed following physical activity with additional HIIE or CME sessions.

Genetic and environmental determinants of the urea level in cow's milk

Abstract. This study was conducted on a sample of 2237 Polish Holstein-Friesian cows. The aim was to estimate the effect of selected environmental factors on the level of urea in cow's milk and on its genetic parameters, i.e. the heritability coefficients, and genetic correlation with other selected traits of milk production. The present study has revealed the existence of a highly significant influence of herd, year of calving, parity, lactation phase, and milk performance level on the urea content in cow's milk. A high urea level in milk was detected in samples collected from older animals, both during the winter season and the middle phase of lactation (101–200 days). The heritability estimates were generally at a low level, particularly in terms of milk yield (0.183) and urea content (0.152–0.159), which may indicate the dominant role of the environment in shaping them. Relatively low values of genetic correlation (−0.097–0.140) between the urea content and other traits suggest that improvement of milk yield and its composition modify the urea level in milk only to a small degree.

Microwave-assisted preparation, structural characterization, lipophilicity, and anti-cancer assay of some hydroxycoumarin derivatives

ABSTRACT

A new series of hydroxycoumarin derivatives has been synthesized using conventional synthesis. The syntheses were accelerated by microwave assistance. Yields in both cases were comparable (59-69 %). The structures were established by 1H and 13C NMR spectroscopy and high-resolution mass spectrometry. Five compounds (5-hydroxy-4,7-dimethylcoumarin, 6-acetyl-5-hydroxy-4,7-dimethylcoumarin, 4-(cyanomethoxy)chromen-2-one, 5-(cyanomethoxy)-4,7-dimethylchromen-2-one, and 6-acetyl-5-(cyanomethoxy)-4,7-dimethylchromen-2-one) were assayed for anti-cancer activity. For all presented coumarin derivatives, lipophilicity was measured using reversed-phase TLC in different eluent systems with standardization. In addition, the crystal structure of 6-acetyl-5-hydroxy-4,7-dimethylcoumarin has been solved by X-ray structure analysis of single crystals.

GRAPHICAL ABSTRACT

Gender differences in carotid artery intima-media thickness and flow-mediated dilatation in young, physically active adults

AIM

The purpose of this study was to examine gender differences (GD) in vascular structure and function and their relations to cardiovascular risk factors (CVD) in young, physically active adults.

METHODS

Sixty-three apparently healthy, physically active adults (34 women, 29 men), aged 20.2±0.9 years, were involved in the study.

RESULTS

Carotid artery intima-media thickness (IMT) values of both internal carotid (CI) and common carotid arteries (CC) were significantly (P<0.01 and P<0.01) higher in men than in women (0.47±0.05 vs. 0.51±0.07 mm and 0.45±0.07 vs. 0.49±0.07 mm, respectively). In women, CC-IMT was positively correlated with body fat mass, height and body mass; and CI-IMT was inversely correlated with systolic and diastolic blood pressure. In men, CI-IMT was positively correlated with body height, diastolic blood pressure and high sensitivity C-reactive protein (hsCRP). Relative values of flow-mediated dilatation (FMD) increased in women by 16.6%, in men by 13.7% after a 5-minute period of forearm ischemia, but absolute FMD was similar in men and women, 0.53±0.25 vs. 0.53±0.14 mm, respectively.

CONCLUSION

Values of CC IMT and CI IMT after adjustment to classical CVD risk factors remained strongly diversified with respect to gender, which confirmed the significance of gender as a conditional factor for atherosclerosis assessment. Some GD in vascular structure and function could be eliminated by adjusting for baseline artery diameter and/or subject's somatic features, i.e., body height. This study supports a need for additional studies focusing on understanding GD in vascular characteristics, which could lead to established better quality reference values and comprehend natural history of CVD in view of pathophysiological mechanisms underlying GD.

The influence of thyroid function and bone turnover on lipoprotein profile in young physically active men with different insulin sensitivity

Physical activity induces changes in the endocrine system. Previous data indicated that changes in insulin secretion and the tissue response to this hormone are very important for energy metabolism. It is believed that they are accompanied by changes in lipid metabolism, but factors contributing to this process are still disputed. The aim of this study was to assess interactions among insulin sensitivity, thyroid function, a bone turnover marker and serum lipid profile in young physically active men. Eighty-seven physical education students, aged 18-23 years, participated in the study. We measured serum levels of glucose, lipids, insulin, thyroid-stimulating hormone (TSH), osteocalcin and anthropometric parameters. Insulin sensitivity was determined using homeostatic model assessment for insulin resistance (HOMA-IR). The median value of HOMA-IR (1.344) was used to divide the study population into Group A (above the median) and Group B (below the median). Men from both groups did not differ in anthropometric parameters or in daily physical activity. Triglycerides (TG), total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C) levels were higher in Group A (P < 0.05). TSH and osteocalcin levels were similar in males with different HOMA-IR. Multiple regression analysis for TSH and osteocalcin showed that in Group A these hormones had no effect on plasma lipoproteins. However, in Group B they significantly determined the variation of plasma TC and low-density lipoprotein cholesterol (LDL-C) levels (in about 28% and 29%, respectively). We concluded that TSH and osteocalcin are involved in determination of a more healthy lipid profile at a certain level of insulin sensitivity.

Association of cognitive performance with the physical activity and body mass index in middle-aged and older rural inhabitants

OBJECTIVE

Last few decades have witnessed rapid ageing of the population. The prevalence of mild cognitive impairment and dementia is significantly higher in people aged 60 and over than in younger. The aim of the study was the assessment of the putative associations between physical activity and cognitive functioning in elderly inhabitants of a rural area.

PATIENTS AND METHODS

The participants underwent physical assessment, physical activity, cognitive functions, depression were assessed.

RESULTS

Highly active participants had better results in tests assessing psychomotor speed and in measuring attention and its flexibility comparing to groups of medium and low physical activity. Active people made fewer errors in the test measuring visual memory and new learning, and had significantly better results in the spatial-recognition memory test. Persons with symptoms of depression performed worse in visuospatial memory and working memory tests. Associations between physical activity and cognitive test results as well as association between body mass index and blood pressure and cognitive performance were observed.

CONCLUSIONS

The results of the study suggest an association between higher physical activity and better cognitive functioning in the field of working memory and visual and spatial-recognition, attention and attention flexibility. Symptoms of depression, hypertension and increased BMI may adversely affect cognitive performance in elderly.

Effect of malathion on nucleic acid synthesis in phytohemagglutinin-stimulated human lymphocytes

The effect of malathion, an organophosphorus insecticide, on DNA and RNA synthesis was investigated by measuring the rate of incorporation of 3H thymidine and 3H uridine, respectively, into human lymphocytes stimulated by phytohemagglutinin (PHA). Increasing concentrations of malathion, from 10 to 70 micrograms/ml, were added to human lymphocyte cultures at different times in relation to PHA introduction. The lowest applied dose of malathion (10 micrograms/ml) in most cases led to increased incorporation of both 3H thymidine and 3H uridine. Higher concentrations of malathion (30, 50, 70 micrograms/ml) caused a time- and dose-dependent decrease of radioisotope incorporation.

Effect of malathion on the genetic material of human lymphocytes stimulated by phytohemagglutinin (PHA)

This paper gives the results of studies on the effects of malathion on human lymphocytes stimulated by PHA, including cell survival, chromosomal aberration and nucleic acid content. Increasing malathion doses (10-70 micrograms/ml) were introduced into cultures of human lymphotyes at different times relative to the time of PHA addition. At a concentration of 10 micrograms/ml, malathion induced an increase in the RNA and DNA fractions in lymphocyte cultures. Higher malathion concentrations (50 and 70 micrograms/ml), especially the dose of 70 micrograms/ml, induced both a significant decrease in the content of RNA and DNA and reduced survival of cultured cells. The insecticide damaged the chromosome structure, but no correlation was revealed between the dose and the level of chromosome aberrations.