Time Of Blood Sampling Research Articles

Evaluation of the covariation between leukotriene B4, prostaglandin E2, and hematologic inflammatory parameters in a canine pentylenetetrazole-induced seizure model

BackgroundSeizures can cause as well as result from neuroinflammation. This study was performed to identify the hematologic inflammatory parameters (HIPs) and inflammatory mediators that change after a single seizure in a canine pentylenetetrazole (PTZ)-induced seizure model.MethodsFive healthy Beagle dogs were used in this study. A 3% solution of PTZ was infused until the occurrence of generalized convulsion. Two separate experiments were conducted to observe changes in HIPs over short and long time periods. Blood sampling time points were divided into two periods as follows: short period (baseline, 30, 60, 90, and 120 min after seizure induction) and long period (baseline, 2, 6, 12, 24, and 48 h after seizure induction). The HIPs were calculated, and the serum prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) concentrations were estimated using enzyme-linked immunosorbent assay.ResultsSignificant changes (p < 0.05) in various HIPs were observed at different time point as follows: neutrophil × monocyte (90 min), neutrophil-to-lymphocyte ratio (60, 90, and 120 min), lymphocyte to monocyte ratio (60 min, 90 min, 120 min, 2 h, 12 h, and 24 h), platelet-to-albumin ratio (90 min), lymphocyte percentage × serum albumin concentration (LA; 60 min, 90 min, 120 min, 2 h), and neutrophil × platelet (6 h). LTB4 concentrations were significantly increased (p < 0.05) at 60 and 90 min, and 2, 6, and 48 h after seizure induction. PGE2 was significantly increased only 6 h after seizure induction (p < 0.05). LA was one of the HIPs that demonstrated a correlation with LTB4 concentration and showed significant changes that could be observed for a long-period (p < 0.05, r = −0.4194).ConclusionThe LA was the only HIP that reflected seizure-associated neuroinflammation. The 5-lipoxygenase pathway might be related to seizure-associated neuroinflammation.

Optimal Blood Sampling Time for Area under the Concentration-Time Curve Estimation of Vancomycin by Assessing the Accuracy of Four Bayesian Software.

Effective blood sampling times, beyond trough and peak levels, have not been determined for estimating vancomycin's area under the concentration-time curve (AUC) using the Bayesian software. The aim of this study was to evaluate the accuracy of AUC estimation at different blood sampling times during the same dosing interval at steady state utilizing data from a prior phase I trial of vancomycin. Six healthy adult participants were sampled following intravenous administration of 1 g vancomycin for 1.5 h every 12 h. The AUC was estimated using four software packages and four population pharmacokinetic models. Accuracy was assessed using bias (difference between the estimated and reference AUC) and imprecision (absolute percentage difference between the estimated and reference AUC). The accuracy varied with the sampling time. The optimal two-point sampling times were determined to be 2.5 and 5.5 h post-injection using software packages for EasyTDM, Practical AUC-guided therapeutic drug monitoring (TDM), and Anti-MRSA Agents TDM Analysis Software (incorporating Rodvold, Yamamoto, and Yasuhara models). In these estimations, the mean bias (range, -1.7 to 9.5 µg·h/mL) was unbiased and the mean imprecision (range, -3.0% to 5.0%) was precise. The optimal one-point sampling time was 5.5 h post-injection for Anti-MRSA Agents TDM Analysis Software, which incorporated the Yamamoto and Yasuhara models. In conclusion, optimal blood sampling times may vary depending on the software and model used. Our findings suggest that identifying specific sampling times could improve the efficacy of TDM in clinical practice.

Efficacy and Blood Levels of Lacosamide in Patients with Focal Epilepsy.

Objectives: The aim of this paper is to analyze clinical targets for lacosamide (LCM) blood levels in patients with focal epilepsy. Referring to the LCM optimal range will encourage us to think about the importance and usefulness of measuring its blood levels. Methods: A total of 101 (45 female, 56 male) patients were treated with LCM. Blood sampling was performed 1 month after the start of oral medication (the levels reached a steady state) if the LCM treatment had been continued, and then 6 and 12 months after. The efficacy of LCM was evaluated by the reduction in the epileptic seizure rate (RR) at the time of blood sampling. The patients were classified as effective cases (seizure reduction rate ≥ 50%) and ineffective cases (<50%). The actual level, the calculated peak/trough levels, and the levels for each type of seizure were investigated. A statistical analysis was performed using Spearman's rank correlation coefficient and the Wilcoxon signed-rank test. Results: A positive correlation was seen between blood levels and dosage (r = 0.446). However, the blood levels and RR showed no correlation. The blood levels were higher in effective cases than in ineffective cases at all time points (measurement p < 0.001, peak p = 0.013, trough p = 0.001). Because the range was set so that the effective and ineffective groups did not overlap, the optimal range of LCM was found to be 8.0-10.5 µg/mL. Conclusions: Measuring and calculating blood levels of LCM and adjusting the dosage to reach the optimal range are recommended. Moreover, the optimal range for LCM was determined as a therapeutic target.

Impact of encounters on patient app use: results of a tethered mobile personal health record usage pattern analysis.

The adoption of tethered mobile personal health records provides not only medical information to patients but also various convenience functions related to hospital use, thereby increasing accessibility to healthcare services and promoting patient engagement. We analyse the tethered mobile personal health records app's usage logs to determine how it can contribute to improving medical service accessibility and patient engagement. Log data, that comprised menu type, log time, and date, were collected from the mobile personal health records app of a tertiary referral hospital. Clinical information, including patients' demographics and visit type, was collected from the clinical research warehouse system. The usage log was analysed in terms of the type of visit, service function, and time period. Outpatients accounted for 34% of the total app usage and was the most app-accessed visit type. The most utilized menu functions were lab test and visit schedule for visits or non-visits. For Inpatient and Health check-ups, menu usage patterns showed a focus on lab test results. While investigations and other menu usage showed double peaks in the morning and afternoon, peak usage of lab test results correlated with inpatient blood sampling times, which was around 9 am. App menus to access health information, particularly blood tests, emerged as the most accessed menu. Hence, when compared with blood sampling times and hospital information system usage patterns, encounters occurring in the hospital majorly impacted patient app use. For improved patient engagement, improving lab test function should be the priority.

Meta-analysis of experimental studies of the effect of melatonin monotherapy on the levels of thyroid hormones and glucocorticoids in rats kept under standard condition

Melatonin is known to modulate circadian and seasonal rhythms in metabolism, reproduction, and behavior. However, the effect of exogenous melatonin supplementation on the functioning of the thyroid and adrenal glands in species without a clear seasonality in reproduction is still unclear. Using a meta-analysis of publications, to investigate the effect of melatonin monotherapy on the concentrations of pituitary thyroid-stimulating hormone, thyroid hormones (TG), pituitary adrenocorticotropic hormone and corticosterone (CS) in rats kept under standard laboratory conditions. In our work, using the Review Manager 5.3 program, we conducted a meta-analysis of publications examining the effect of melatonin monotherapy on the functioning of the thyroid gland (22 papers) and adrenal glands (20 papers) in rats kept under standard conditions. According to the results of our meta-analysis, the effects of melatonin on the levels of TG and CS depend on the dose and duration of therapy. A decrease in TG and CS was associated with therapy lasting no more than 4-5 weeks and with high doses of melatonin. An increase in CS and a trend toward increased TG levels were observed with longer therapy. However, a few studies have observed a decrease in TG with very long-term melatonin therapy (≥32 weeks). Among all TGs, total thyroxine (T4) showed maximum sensitivity to exogenous melatonin, which indicates the influence of melatonin on the secretory function of the thyroid gland. In addition, melatonin increased the relative weight of the adrenal glands. There was no convincing evidence that the effects of melatonin were influenced by the route and timing of administration, or the timing of blood sampling. As a result, exogenous melatonin can modulate TG and CS levels, even in species without a clear seasonality in reproductive function.

Effect of Blood Sampling Time After Colostrum Intake on the Concentration of Metabolites Indicative of the Passive Immunity Transfer in Newborn Dairy Calves.

Due to the synepitheliochorial placental structure, bovines show no maternal antibody flow from mother to fetus during pregnancy, resulting in an agammaglobulemic newborn [...].

Phenotypes and clinical laboratory data for polycystic ovary syndrome cases: A nationwide survey in Japan.

Describe the current phenotypes and clinical laboratory data regarding polycystic ovary syndrome (PCOS) in Japan, taking into account ethnic differences and obesity status. Data for 986 PCOS cases and 965 control cases were collected using a nationwide survey in Japan. Obese/overweight (body mass index [BMI] ≥25 kg/m2) and non-obese/overweight (BMI <25 kg/m2) cases were compared. Japanese PCOS cases predominantly involved non-obese/overweight patients, accounting for 75% of all cases. Among non-obese/overweight PCOS cases, the incidence of both amenorrhea and clinical/biochemical hyperandrogenism was significantly lower than in obese/overweight PCOS cases, whereas the rate of elevated serum luteinizing hormone (LH) level was significantly higher. Even though the incidence of hirsutism in Japan is only 13.5%, the detection rate for hyperandrogenism increased by as much as 30.4% when hirsutism was added to the Japan Society of Obstetrics and Gynecology (JSOG) criteria for the diagnosis of hyperandrogenism in addition to elevated serum total testosterone level. When evaluated based on timing of blood sampling, the LH level and LH/follicle-stimulating hormone ratio determined at the initial consultation involving a chief complaint of irregular menstrual cycle (after confirming the absence of follicles measuring ≥1 cm in diameter) were significantly higher than on days 2-3 or 4-6 of the menstrual cycle. Ethnic differences, including obesity status, affected the phenotype and clinical laboratory data of Japanese PCOS patients, such as the incidence rates of clinical/biochemical hyperandrogenism and the rate of elevated basal LH level. Adding hirsutism to the JSOG 2024 criteria would enhance the accuracy of PCOS diagnosis and enhance consistency with the Rotterdam 2003 criteria. Measuring basal LH level is useful for assessing the endocrinologic characteristics of Japanese PCOS cases, as well as lean Asian PCOS cases, but the timing of blood sampling can affect the result.

Serum concentrations of lipids, ketones and acylcarnitines during the postprandial and fasting state: the Postprandial Metabolism (PoMet) study in healthy young adults.

To improve the interpretation and utilisation of blood lipids, ketones and acylcarnitine concentrations as biomarkers in clinical assessments, more information is needed on their dynamic alterations in response to dietary intake and fasting. The aim of this intervention study was to characterise the changes in serum lipid, ketone and acylcarnitine concentrations 24 h after a standardised breakfast meal. Thirty-four healthy subjects (eighteen males and sixteen females) aged 20-30 years were served a breakfast meal (∼500 kcal, 36 E% fat, 46 E% carbohydrates, 16 E% protein, 2E% fibre), after which they consumed only water for 24 h. Blood samples were drawn before and at thirteen standardised timepoints after the meal. Metabolite concentrations were plotted as a function of time since the completion of the breakfast meal. Results demonstrated that concentrations of HDL-cholesterol and LDL-cholesterol decreased until ∼2 h (-4 % for both), while TAG concentrations peaked at 3 h (+27 %). Acetoacetate and β-hydroxybutyrate were highest 24 h after the meal (+433 and +633 %, respectively). Acetylcarnitine, butyrylcarnitine, hexanoylcarnitine, octanoylcarnitine, decanoylcarnitine and dodecanoylcarnitine reached the lowest values at 60 min (decreases ranging from -47 to -70 %), before increasing and peaking at 24 h after the meal (increases ranging from +86 to +120 %). Our findings suggest that distinguishing between fasting and non-fasting blood samples falls short of capturing the dynamics in lipid, ketone, carnitine and acylcarnitine concentrations. To enhance the utility of serum acylcarnitine analyses, we strongly recommend accounting for the specific time since the last meal at the time of blood sampling.

Human milk feeding practices and serum immune profiles of one-year-old infants in the CHILD birth cohort study

BackgroundBreastfeeding and human milk consumption are associated with immune system development; however, the underlying mechanisms and the impact of different infant feeding practices are unclear. ObjectivesThis study aimed to investigate how current human milk feeding (HMF) status is related to infant immune biomarker profiles, as well as explore relationships with HMF history (i.e., duration, exclusivity, and method: directly from the breast or pumped and bottled). MethodsThis observational birth cohort study involved 605 infants from the Canadian CHILD Cohort Study. Infant feeding was captured from hospital birth records and parent questionnaires. Ninety-two biomarkers reflecting immune system activity and development were measured in serum collected at 1 y (12.6 ± 1.4 mo) using the Olink Target 96 Inflammation panel. Associations were determined using multivariable regression (adjusted for sex, time until blood sample centrifugation, and study site). ResultsNearly half (42.6%) of infants were still receiving HMF at the time of blood sampling. Compared with non-HMF infants, HMF infants had higher levels of serum fibroblast growth factor 21 (FGF-21, adjusted standardized β coefficient: 0.56; 95% CI: 0.41, 0.72), cluster of differentiation 244 (CD244, β: 0.35; 95% CI: 0.19, 0.50), chemokine ligand 6 (CXCL6, β: 0.34; 95% CI: 0.18, 0.50), and chemokine ligand 20 (CCL20, β: 0.26; 95% CI: 0.09, 0.42) and lower extracellular newly identified receptor for advanced glycation end-products binding protein (EN-RAGE, β: −0.16; 95% CI: −0.29, −0.03). Among non-HMF infants, serum interleukin 7 (IL-7) had a marginally positive association with past HMF duration (β: 0.05; 95% CI: 0.02, 0.08) that persisted for ≤5 mo post-HMF cessation. Exclusive HMF duration and HMF method (at 3 mo of age) were not associated with any biomarkers. ConclusionsCurrent HMF status and (to a lesser extent) HMF history are associated with several inflammation-associated biomarkers in 1-y-old infants. These results provide new evidence that HMF impacts immune activity and development and suggest hypotheses about the underlying mechanisms. They also highlight the importance of including current HMF status in immune system–focused infant serum proteomic studies.

Interpretation of TSH results can be improved by reference values fluctuating in time.

The secretion of thyroid stimulating hormone (thyrotropin, TSH), is characterized by a marked circadian rhythm. Plasma or serum TSH values are significantly lower in the afternoon and in the evening as compared to the early morning. As in clinical practice, blood sampling time shows an important variation, a reliable assessment of thyroid status is often not an easy task for the clinician. The biological variation of TSH plays a major role in the intra-individual variability of TSH results in serum or plasma. The observed intra-day variation largely exceeds the reported inter-vendor variation and the coefficient of variation of clinical TSH assays. Therefore, a mathematical solution was sought for correcting interpretation of TSH results for sampling time. We have developed a cosinor model which allows to compensate TSH decision values for the fluctuating serum or plasma TSH concentrations throughout the day. The following mathematical function could be derived: corrected TSH cutoff_value (mIU/L)=0.40+0.24*cos(((π/12) *T)+6) in which T represents the time (hours). This mathematical function can be easily implemented into a laboratory's informatics system and furthermore allows a better tailored diagnosis of (subclinical) hyperthyroidism, regardless the blood sampling time. Implementing the corrected cut-off values result in a marked reduction of apparent (false positive) hyperthyroidism diagnosis, in particular in the afternoon.

Biochemical Amenability in Fabry Patients Under Chaperone Therapy-How and When to Test?

Current recommendations for Fabry disease include α-galactosidase A (AGAL) activity measurements to assess the biochemical response in migalastat-treated patients. Owing to contradictory data from laboratories, we aimed to analyze why AGAL activity measures from dried blood spots (DBS) often fail to detect migalastat-mediated enzymatic activity increases in treated patients. 43 patients with 58 visits under migalastat were consecutively recruited. Enzymatic AGAL activities were measured from DBS and peripheral blood mononuclear cells (PBMCs). Migalastat concentrations in sera were determined using modified serum-mediated inhibition assays to assess Cmax and serum half-life. Results were set in relation to the time of last migalastat intake and blood sampling to assess an optimal timepoint for AGAL activity measures. DBS-based AGAL activity measurements of 21 (42.0%) amenable patients were below the limit of detection. Serum samples from migalastat-treated patients showed significant AGAL inhibition, depending on the time between migalastat intake and blood sampling (r2 = 0.8140, p < 0.0001). Migalastat concentrations were determined in serum samples confirming a Cmax at 3 h and a serum half-life of 4 h. At 24 h after intake, migalastat clearance was significantly associated with renal function (r2 = 0.3135, p = 0.0102). Enzymatic AGAL activities were higher in samples from DBS and PBMCs 24 h after migalastat intake (both p < 0.05). The optimal time for enzymatic AGAL activity measurement in migalastat-treated patients appears to be 24 h after the last migalastat intake. Since migalastat is a competitive inhibitor of AGAL, enzymatic AGAL activity measurements should be better performed from PBMCs to reduce migalastat-mediated interferences.

Ghrelin may protect against vascular endothelial injury in Acute traumatic coagulopathy by mediating the RhoA/ROCK/MLC2 pathway.

Ghrelin exerts widespread effects in several diseases, but its role and mechanism in Acute Traumatic Coagulopathy (ATC) are largely unknown. The effect of ghrelin on cell proliferation was examined using three assays: 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT), Lactate Dehydrogenase (LDH), and flow cytometry. The barrier function of the endothelial cells was evaluated using the Trans-Endothelial Electrical Resistance (TEER) and the endothelial permeability assay. An ATC mouse model was established to evaluate the in vivo effects of ghrelin. The Ras homolog family member A (RhoA) overexpression plasmid or adenovirus was used to examine the molecular mechanism of ghrelin. Ghrelin enhanced Human Umbilical Vein Endothelial Cells (HUVEC) proliferation and endothelial cell barrier function and inhibited HUVEC permeability damage in vitro. Additionally, ghrelin decreased the activated Partial Thromboplastin Time (aPTT) and Prothrombin Time (PT) in mice blood samples in the ATC mouse model. Ghrelin also improved the pathological alterations in postcava. Mechanistically, ghrelin acts through the RhoA/ Rho-associated Coiled-coil Containing Kinases (ROCK)/ Myosin Light Chain 2 (MLC2) pathway. Furthermore, the protective effects of ghrelin, both in vitro and in vivo, were reversed by RhoA overexpression. Our findings demonstrate that ghrelin may reduce vascular endothelial cell damage and endothelial barrier dysfunction by blocking the RhoA pathway, suggesting that ghrelin may serve as a potential therapeutic target for ATC treatment.

Dialoxygenation: A Preclinical Trial for Transforming the Artificial Kidney Into an Oxygenator.

Critically ill patients sometimes require tandem application of extracorporeal membrane oxygenation (ECMO) and continuous renal replacement therapy (CRRT) which is easier and cheaper. We aimed to transform the kidney membrane into a lung membrane by adding hydrogen peroxide (H 2 O 2 ) to the dialysate as the oxygen source. A solution containing H 2 O 2 and a dialysate fluid mixture was used as the final dialysate. Starting with 100% H 2 O 2 solution and gradually reducing the volume of H 2 O 2 , respectively: 50%, 10%, 5%, 4%, 3%, 2%, and 1%. PRISMAFLEX system, Prismaflex M60 set and a bag of packed red blood cells (pRBCs) were the prototype. blood flow rate was about 40 ml/minute and the dialysis rate was about 200 ml/m 2 /minute/1.73 m 2 . blood sampling times were; at the beginning ( T0 ), at 15th ( T1 ), 30th ( T2 ), 60th ( T3 ) minutes. Amongst eight attempts H 2 O 2 concentration that increased the partial oxygen pressure (pO 2 ) level significantly in a reasonable period, without any bubbles, was 3%. Methemoglobinemia was not observed in any trial. After the test with 3%, H 2 O 2 in the dialysate fluid decreased progressively without any H 2 O 2 detection at post-membrane blood. Three percent H 2 O 2 solution is sufficient and safe for oxygenation in CRRT systems. With this new oxy-dialysate solution, both pulmonary and renal replacement can be possible viaa single membrane in a simpler manner.

Production responses of multiparous dairy cattle with differing prepartum muscle reserves and supplementation of branched-chain volatile fatty acids

Periparturient dairy cattle undergo physiological adaptations to support fetal growth and colostrum synthesis in late gestation and milk production in early lactation. To support energy and protein demands dairy cattle mobilize body tissue reserves. The objective of this study was to determine the effects of prepartum skeletal muscle reserves and supplementation of branched-chain volatile fatty acids (BCVFA) on body composition measurements, metabolic markers related to health, protein, and energy status, and subsequent milk yield in multiparous dairy cows. Skeletal muscle reserves were assessed by 3 ultrasounds of the longissimus dorsi muscle depth (LDD) measured 42 d before expected calving (BEC), and cows (n = 48) were assigned to either high muscle (HM; > 4.6 cm) or low muscle (LM; ≤ 4.6 cm) groups. Cows were then randomly assigned to either control (CON) of soyhull pellets (80 g/d) or BCVFA treatment which contained isobutyrate (40 g/d), isovalerate (20 g/d), and 2-methylbutyrate (20 g/d) calcium salt products. Treatments were top dressed from 42 BEC until parturition, resulting in 4 combinations of muscle groups and treatments: HM-CON (n = 13), HM-BCVFA (n = 13), LM-CON (n = 11), and LM-BCVFA (n = 11). Measurements of the LDD, BW, and BCS were taken on the following days relative to calving -42, -35, -21, -7, 0, 7, 14, 21, 28. Weekly blood samples were taken to measure glucose, BHB, and insulin concentrations, and 5 of the blood sample time points were utilized to determine 3-methylhistidine and creatinine blood concentrations. Milk yield was recorded daily for the first 28 d of lactation, and samples were taken from both milkings once a wk for the first 4 wk to determine components. The statistical model included the fixed effects of treatment, group, time, their interactions, and the random effect of cow nested within group and treatment. Prepartum muscle mobilization varied between muscle groups, as LM cows accreted muscle prepartum, and HM cows mobilized muscle. The HM cows had higher milk fat, protein, lactose, and energy corrected milk yields. The BCVFA supplementation tended to increase blood glucose concentrations both prepartum and postpartum and decreased milk urea nitrogen concentrations. Higher prepartum skeletal muscle reserves improve productivity of early lactation cows likely due to differences in muscle mobilization, and BCVFA supplementation improves glucose dynamics during the transition period, which may improve the metabolic health of the periparturient dairy cow.

A validated UPLC-MS/MS method for the quantification of immunosuppressive drugs in peripheral blood mononuclear cells using liquid-liquid extraction with low temperature purification without complex pretreatment steps

Immunosuppressive drugs (ISDs) are given to avoid the allograft rejection after transplantation. The concentrations of ISDs should be closely monitored owing to their wide inter-individual variability in its pharmacokinetics and narrow therapeutic window. Currently, the whole blood concentration measurement is the major approach of therapeutic drug monitoring of clinical ISDs in organ transplantation. Its correlation with the efficacy of ISDs remains elusive. While the acute rejection after transplantation may occur even when whole-blood ISDs concentrations are within the target range. Since the site of action of ISDs are within the lymphocyte, direct measurement of drug exposure in target cells may more accurately reflect the clinical efficacy of ISDs. Although several methods have been developed for the peripheral blood mononuclear cells (PBMCs) extraction and drug concentration measurement, the complex pre-processing has limited the study of the relationship between intracellular ISDs concentrations and the occurrence of rejection. In this study, the extraction of ISDs in PBMCs was carried out by the liquid-liquid extraction with low temperature purification, without centrifugation. The lower limit of quantitation were 0.2 ng/mL for cyclosporine A, tacrolimus and sirolimus, 1.0 ng/mL for mycophenolic acid, and the within-run and between-run coefficient of variations were both less than 12.4 %. The calibration curves of mycophenolic acid had a linear range (ng/mL): 1.0–128.0 (r2 = 0.9992). The calibration curves of other three ISDs had a linear range (ng/mL): 0.2–20.48 (r2 > 0.9956). A total of 157 clinical samples were analyzed by the UPLC-MS/MS for ISDs concentration in blood or plasma ([ISD]blood or plasma) and the concentration within PBMCs ([ISD]PBMC). Although there was strong association between [ISD]PBMC and [ISD]blood or plasma, the large discrepancies between concentration within [ISD]blood or plasma and [ISD]PBMC were observed in a small proportion of clinical samples. The developed method with short analysis time and little amounts of blood sample can be successfully applied to therapeutic drug monitoring of ISDs in PBMCs for analysis of large numbers of clinical samples and is helpful to explore the clinical value of ISDs concentration in PBMCs.

Conversion from the frequency of chromosome translocations in T-lymphocytes to the bone marrow dose in the long-term period after internal 89,90 Sr exposure

Cytogenetic Fluorescence In Situ Hybridization studies, that allow assessing the frequency of stable chromosome aberrations in circulating T lymphocytes, are commonly used in retrospective dosimetry in cases of uniform whole-body exposure. In the event of 89,90Sr exposure, interpretation of cytogenetic data is challenging, especially if blood sampling occurs long after the start of exposure. The weighted average dose to T-lymphocytes at the time of donor blood sampling in the long-term period after exposure to 89,90Sr does not coincide with the red bone marrow dose. Previously, we developed a model that allows us to estimate the weighted average doses to T-lymphocytes upon 89,90Sr ingress into the body of people belonging to various age groups. In this study, the modeling results were used to estimate the conversion factors from the frequency of translocations to the red bone marrow dose, which is important for assessing radiobiological effects associated with hematological diseases. The objective of our study is to estimate numerically the conversion factors (Brbm) from the dose to lymphocytes to the dose to red bone marrow for various scenarios of 89,90Sr ingestion depending on age, sex, and time after the start of exposure. The following scenarios are considered: single, uniform chronic for six months, uniform chronic for 1-5 years, non-uniform intake for 5 years (simulates the dynamics of intake in the Techa riverside settlements in 1950-1954). As a result, it has been found that the Brbm values significantly depend on the age at the time of 89,90Sr intake. The older the person is at the start of exposure, the more the cytogenetic dose differs (it is significantly lower) from the dose to the red bone marrow. We can say that the cytogenetic dose corresponds to the red bone marrow dose only in newborns and infants. This is due to the age-related dynamics of T-cell populations. Sex does not have a significant effect on Brbm. The effect of the 89,90Sr intake duration on Brbm is the most pronounced for 15-year-old adolescents. For them, the difference in Brbm values for a single and chronic 5-year ingress reaches 13%. Non-uniform intake of 90Sr over several years does not have a significant effect on Brbm and can be modelled by a uniform intake of the same duration.

Improving 1-Deamino-8-D-Arginine Vasopressin (DDAVP) Challenges in Pediatric/Young Adult Patients With Bleeding Disorders: A Quality Improvement Study.

Background: Desmopressin (1-deamino-8-D-arginine vasopressin [DDAVP]) has demonstrated efficacy as a treatment option for patients with inherited bleeding disorders. Because of individuals' variable response to the medication, it is recommended to complete a challenge to document appropriate hemostatic response to the medication before recommending its use prior to surgical procedures or treatment of bleeding symptoms. The project aimed to reduce the errors in hemostatic response assessments for patients with bleeding disorders undergoing a DDAVP challenge (process outcome), particularly timing and number of blood samples drawn, from an error rate baseline of 36% to 0% by December 2021 and sustained for one year. Method: Plan-Do-Study-Act methodology was employed for this qualitative improvement initiative. Interventions designed and implemented included: an order set with medication doses and corresponding laboratory orders as clinically indicated for the bleeding disorder indication, clinical procedure guidelines for infusion nurses to follow, hemostasis nurse coordination of appointments with patients, and family education. Results: Baseline data on 22 patients who completed a DDAVP challenge demonstrated a 36% error rate not involving doses of medication administered. Errors encountered included improper timing of laboratory draw after DDAVP administration, incomplete laboratory evaluation, laboratory results displayed incorrectly due to testing orders released at once instead of in a sequential manner. These interventions resulted in a reduction of DDAVP challenge errors to 0% that were sustained for one year. Conclusion: Improvement in procedural medication administration and appropriate laboratory evaluation of patients undergoing a DDAVP challenge leads to a complete and reliable assessment of hemostatic response following medication administration.

Effects of sodium intake, age, gender, blood sampling time on distribution of plasma aldosterone, renin activity, deoxycorticosterone, cortisol, cortisone, and 24 h urinary aldosterone levels in normotensive individuals based on LC-MS/MS.

This study aims to analyze the distribution of plasma aldosterone, renin activity, deoxycorticosterone (DOC), cortisol, cortisone, and 24 h urinary aldosterone (24 h-uAld) levels based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. Plasma and 24 h urine were collected from 129 healthy volunteers in Northeast China. The effect of sodium intake, age, gender, blood sampling time on plasma aldosterone concentration (PAC), plasma renin activity (PRA), PAC to PRA ratio (ARR), DOC, cortisol, cortisone, cortisol to cortisone ratio, and 24 h-uAld were investigated by nonparametric test, multiple linear regression and Harris-Boyd's standard deviate test. There was no significant difference observed in 24 h-uAld, PAC (AM), PRA(AM), ARR (AM), DOC (AM), cortisol (AM), cortisone (AM), and cortisol to cortisone (AM) between high and low sodium intake group. Significant differences were observed between morning and afternoon sampling groups in terms of PAC, ARR, DOC, cortisol, and cortisone. Reference intervals (RIs) of 24 h-uAld, PAC (AM) were recommended to be partitioned by gender. RI of PRA was recommended age stratification. We recommend that the same reference interval could be used regardless of sodium intake. Gender is the main influence factor for 24 h-uAld, PAC, and ARR. Age is key influence factor for PRA.

#2422 Iohexol plasma clearance measurement protocol standardization—a consensus of the European Kidney Function Consortium

Abstract Background and Aims International consensus supports the development of standardized protocols for measured glomerular filtration rate (mGFR) to facilitate the adoption of mGFR determination in both clinical and research settings. Method The European Kidney Function Consortium (EKFC) convened an international group of mGFR experts. The working group performed an extensive literature search to inform the development of recommendations for mGFR determination using one-compartment plasma clearance models and iohexol as the exogenous filtration marker. Iohexol was selected as it is non-radio labeled, inexpensive, widely available, and can be assayed at a central laboratory. Other commonly used non-radio labeled tracers have been (inulin) or are soon to be (iothalamate) discontinued. A plasma clearance model was selected as it requires no timed urine collections. A one-compartment model was preferred to a two compartment model as it requires fewer samples. The resulting recommendations were based on published evidence complemented by expert opinion. Results Recommendations include practical advice for patients and health professionals, preparation, administration and safety aspects of iohexol, laboratory analysis, blood sample collection and sample timing for both multiple and single sample protocols, description of the mGFR mathematical calculations as well as implementation strategies (Fig.). EKFC will provide materials such as patient information sheets, standard operating procedures, a study protocol template, and support for mGFR calculation. Conclusion Members of the EKFC have evaluated the evidence and formulated recommendations that include all aspects of iohexol plasma clearance measurement using a one compartment model. *Author list on behalf of the European Kidney Function Consortium (EKFC).

Evidence-based practice in canine artificial insemination.

A number of methods are currently used to predict the optimal date of insemination of the breeding bitch, particularly with the use of frozen-thawed canine semen which has a far shorter lifespan than fresh semen. Aside from confirming cytological oestrus, vaginal cytology is of no assistance in predicting the most fertile day(s) in a bitch; however, a neglected avenue of research suggests that vaginal cytology may be of great importance in confirming the days of optimal fertility retrospectively. Similarly, vaginoscopy provides clues as to the stage of a bitch's cycle but is inadequate as a sole determinant of her most fertile days. Nevertheless, vaginoscopy is useful to identify very late oestrus and the onset of dioestrus, as well as Stage I of labour (cervical dilatation). Due to variations in the rate at which circulating progesterone concentrations rise in individual bitches, the reliability of circulating progesterone concentrations for determining the optimal day(s) of insemination with frozen-thawed semen decreases as values rise. Moreover, progesterone assay results can vary widely due to extrinsic factors such as the time of blood sampling, sample storage conditions and the assay employed. Finally, this review investigates evidence surrounding various insemination routes and suggests that well-performed vaginal insemination, even with frozen-thawed semen, may be an acceptable approach for cases where transcervical insemination is impractical.