Total Plasma Calcium Research Articles

Measurement of plasma total calcium before plasma free ionized calcium – a possibility with affordable pitfalls

Free ionized calcium (fCa) is considered the gold standard for assessing calcium status in patients, but it is relatively expensive and is associated with several preanalytical and analytical error sources. We investigated the feasibility of using a reflex test that involves first measuring total calcium (tCa) and if out of reference range, then measure fCa, with expectation of reducing the number of fCa measurements. We used data from 1815 unique patients with concurrent measurement of fCa, tCa and albumin adjusted calcium (aCa). Patients were stratified by albumin level, and the association of fCa to tCa and aCa respectively was assessed with linear regression. The regression analysis showed the best linearity for tCa and aCa at albumin <35 g/L (R 2: 0.80–0.90), and the poorest at albumin >40 g/L (R 2: tCa 0.58; aCa 0.59). We examined the accuracy of hypo- and hypercalcemia classifications for tCa, aCa and the reflex test. aCa had more misclassifications of hypo- and hypercalcemia than tCa, with respectively 25% and 21%. Implementation of the reflex test would correct any false hypo- or hypercalcemia classified by tCa, leaving only false negative results corresponding to 9% of all tCa measurements. False negative results were on average 0.04 mmol/L above or below the reference range of fCa. Implementation of the reflex test reduces the number of fCa by 68% without major errors diagnosing hyper- or hypocalcemia.

Cordymin alleviates osteoporosis induced by hindlimb unloading via regulating the gut - microelements -bone axis --for non-clinical studies

IntroductionThe purpose of this study was to evaluate the protective effects of cordymin on osteoporosis induced by hindlimb unloading(HLU) in rats and whether cordymin can prevent bone loss from HLU.Materials and methodsWe employed the hindlimb suspension rats model to mimic physiological changes concomitant with space travel.The mechanical strength in the femoral neck,cancellous bone volume, gut microbiota structure,serum calcium and phosphorus contents, bone mineral content and bone mineral content can be changed after hindlimb unloading. Oral cordymin was administered for 4 weeks,cordymin treatment significantly increased the mechanical strength through elevated bone volume/tissue volume (BV/TV), trabecular number (Tb. N), trabecular thickness (Tb. Th) and decreased trabecular separation (Tb. Sp).ResultsImportantly, 16 S rRNA sequencing showed cordymin treatment regulated the various genera that were imbalanced in hindlimb unloading rats. At the same time,The plasma total calcium and inorganic phosphate concentrations in hindlimb unloading rats decreased and bone mineral content in the lumbar vertebrae and femur increased after treatment with cordymin.ConclusionThese data indicate that the cordymin might exert bone protective effects indirectly via modulating the complex relationship between gut microbiota, microelements and bone loss.

Association of hypertension in pregnancy with serum electrolyte disorders in late pregnancy among Cameroonian women

Multiple electrolyte disorders, including sodium, potassium and calcium disorders, have been associated with hypertension in pregnancy. Most of these studies failed to evaluate the combined effect of low and high sodium, potassium, calcium and chloride ion concentrations on hypertension in pregnancy. This study evaluates the combined effect of these ion categories (low, normal, high) on hypertension in pregnancy. Biochemical ion assays and blood pressure measurements were carried out on 1074 apparently healthy pregnant women in late third trimester. Serum potassium, sodium, chloride, and ionised calcium were measured by ion-selective electrode potentiometry, while total plasma calcium was measured by absorption spectrophotometry. Hypertension in pregnancy was defined as systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg. The prevalence of hyponatraemia, hypokalaemia, hypochloraemia, ionised hypocalcaemia and total hypocalcaemia in late pregnancy was 1.30 [0.78–2.18]%, 3.55 [2.60–4.84]%, 1.96 [1.28–2.97]%, 1.49 [0.92–2.21]% and 43.58 [40.64–46.56]%, respectively. Hypernatraemia, hyperkalaemia, hyperchloraemia, ionised hypercalcaemia and total hypercalcaemia were found in 1.49 [0.92–2.41]%, 2.34 [1.59–3.43]%, 4.38 [3.31–5.77]%, 39.94 [37.06–42.90]%, 2.79 [1.96–3.96]% of the participants, respectively. The prevalence of hypertension in pregnancy was 7.17 [5.77–8.87]%. When ion categories were considered in multiple logistic regression, only ionised and total calcium had significant associations with hypertension in pregnancy. Women with ionised hypercalcaemia had lower odds of hypertension in pregnancy (AOR = 0.50 [0.29–0.87], p-value = 0.015), and women with total hypocalcaemia had higher odds of hypertension in pregnancy (AOR = 1.99 [1.21–3.29], p-value = 0.007), compared to women with ionised and total normocalcaemia, respectively. Increasing kalaemia was associated significantly with higher odds of hypertension in pregnancy; however, kalaemia below and above the normal concentrations had no significant association with hypertension. Nonetheless, participants with kalaemia ≤ 3.98 mmol/L, had lower odds of hypertension in pregnancy compared with those with higher kalaemia (OR = 0.40 [0.24–0.66], p-value = 0.0003). Calcium disorders remain the most frequent electrolyte disorders in pregnancy. When normal cut-offs are considered for calcium and other ions, only ionised and total calcium influence the occurrence of hypertension in pregnancy. Kalaemia seems to affect hypertension in pregnancy but primarily within its normal concentrations. Serum electrolyte follow-up is indispensable for a proper pregnancy follow-up.

SAT238 Ionophore-based Chemical Sensors For At-home Blood Calcium Monitoring

Abstract Disclosure: N. Ghanbari Ghalehjoughi: None. N. Adil: None. X. Wang: None. At-home blood calcium monitoring may revolutionize the management of hypoparathyroidism similarly as glucose meters have done for diabetes management. Measurements of ionized calcium in whole blood via ion-selective electrodes and total calcium in plasma via chromogenic probes have been routinely performed in hospitals for decades. However, calcium monitoring in resource-limited settings such as at home remains challenging. One reason is that large volumes of blood (&amp;gt; 95 μL) are needed for tests using current technologies, which are hard to collect from fingerpicks by patients. Another reason is that complicated and costly designs are used to handle fluids and perform on-site calibration. My group is developing two types of ionophore-based chemical sensors for highly selective detection of blood calcium via low-cost devices and less than 10 μL of capillary blood from the fingertip. In one direction, we develop highly sensitive colorimetric sensors that detect total calcium concentration in blood. Our novel biphasic sensing design does not suffer from optical interference from the colored and turbid blood and therefore tests blood without pretreatment processes. A smartphone with a color analysis app is used to acquire and analyze the colorimetric response to blood samples. In another direction, we develop electrochemical sensors that detect ionized calcium in blood without any fluid handling or on-site calibration. An innovative self-calibration method is designed to reduce the sensor-to-sensor variations and assure the accuracy of the calcium electrodes. The goal is that these methods will empower patients to self-monitor blood calcium and self-manage parathyroid disorders. Presentation: Saturday, June 17, 2023

Plasma Concentrations of Calcium and Risk of Alzheimer Disease-Observational and Genetic Studies.

Dysregulation of calcium ion homeostasis in neurons is well documented in Alzheimer disease (AD), and high plasma calcium concentrations have been associated with cognitive decline in the elderly; however, a potential causal nature for this association has not been elucidated. Plasma calcium ion concentrations of 97 968 individuals from the Copenhagen General Population Study (CGPS) were included and multifactorial Cox regressions using splines or quartiles was performed to investigate the observational association. A plasma calcium ion genome-wide association study (GWAS) was performed in 2 independent subgroups of the CGPS. The plasma calcium ion GWAS and publicly available genomic data sets for plasma total calcium and AD were used to perform the currently most powerful 2-sample Mendelian randomization studies. The hazard ratio for lowest vs highest quartile of the calcium ion concentration was 1.24 (95% CI, 1.08-1.43) for AD. The plasma calcium ion GWAS identified 3 independent loci. None of the genetic instruments for plasma concentrations of calcium ions or total calcium were associated with AD risk. High plasma concentrations of calcium ions were observationally associated with increased risk of AD but genetic associations were not found, suggesting that the observational findings may be due to reverse causation or residual confounding.

Association between Serum Calcium Concentration and Glycated Haemoglobin in Type II Diabetic Nigerian Patients

Background: Diabetes is a metabolic disease that affects key biochemical parameters in the body. The study was carried out to evaluate the serum calcium concentration and the relationship between serum calcium and glycosylated haemoglobin in type 2 diabetics. Methods: A total of 126 subjects consisting of 63 Diabetic patients and 63 controls participated in this study. Serum calcium and glycosylated haemoglobin concentrations were measured. Fasting blood sugar was also measured. Total calcium was measured using colorimetric determination of plasma total calcium by the o-cresolphthalein o-complexone (CPC) assay principle. Plasma albumin was determined using Bromocresol green (BCG) method, and thus corrected calcium was deduced. Glycosylated haemoglobin (HbA1C) was estimated using an ion-exchange chromatographic method. A semi-structured questionnaire was used for data collection. Results: The mean serum calcium levels of diabetics compared to non-diabetics did not differ statistically even though that of diabetics was in the lower range of normal. There was no statistically significant difference (p=0.099) between the mean serum calcium levels of diabetic patients who had glycosylated haemoglobin values below 6.5 (2.26 mmol/l±0.07) and diabetic patients who had glycosylated haemoglobin values above 6.5 (2.17mmol/l±0.09). Surprisingly, there was a weak positive correlation between glycosylated haemoglobin levels above 6.5 and serum calcium levels (p=0.087) and HbA1C below 6.5 correlated negatively albeit weakly with serum calcium levels though they were both insignificant. Socio-demographic data show that more females were diabetic. Conclusion: Overall, the study reveals that mean serum calcium concentrations in diabetic and non-diabetic patients are not different and this may be due to good blood glucose control in these diabetic patients

Correlation Depending on Age Between Saliva and Plasma Parameters

Abstract Introduction. Because of the increasing interest in the study of saliva, many methods have become available that can allow us to perform multiple and rapid analyzes of the composition of salivary secretion using advanced techniques of nanotechnology and fluid micro- engineering. The objectives of our study were to identify immunoglobulin levels variations with age. Materials and methods. We conducted an analysis to check the correlation between saliva and plasma parameters on 24 patients. The study population was divided into 2 groups based on age, with a cut-off at 35 years. The differences on the variables between two groups were evaluated by TTEST and CORREL. Results. Total plasma calcium, as well as ionic calcium have increased values in group 2, the increase being statistically significant (p =0.04) only for ionic calcium. Significant correlation of plasma and salivary values in the case of IgA / IgG ratio, and also a significant correlation of salivary and plasma concentrations for IgG were identified in our study. Conclusions. The correlation between plasma and salivary parameters is closely related to age and these can be used as markers for diagnosis and evaluation of various pathologies. Also, regarding women, salivary calcium and phosphate concentrations increase with age showing peak values around menopause.

RF30 | PSAT136 Gitelman Syndrome and Primary Hyperparathyroidism, a Case Report

Abstract Introduction Gitelman syndrome, also known as familial hypokalemia-hypomagnesemia, is a rare autosomal recessive disorder that impairs the sodium chloride cotransporter (NCC) and magnesium channels in the renal distal convoluted tubule, causing salt-losing tubulopathy. It is characterized by hypokalemia, hypomagnesemia, hypocalciuria, and secondary hyperaldosteronism. Although hypocalciuria is a distinctive characteristic of Gitelman syndrome, it seldom can cause any change in the total plasma calcium level. Thus, the occurrence of hypercalcemia would need further investigation. Case presentation We reported a case of a 36-year-old normotensive man with a past medical history significant for bipolar depression disorder and a history of chronic atrial fibrillation secondary to chronic hypokalemia, hypomagnesemia, and mild hypercalcemia. He was diagnosed with Gitelman syndrome. However, he was noncompliant with spironolactone, potassium, and magnesium supplementation. He suffered a motor vehicle accident, and on presentation to the emergency room, he was found with a serum potassium of 2.5 mEq/L (reference value 3.5-5.1), serum magnesium of 0.8 mEq/L (reference value 1.6-2.6), total serum calcium of 11.3 mEq/L (reference value 8.4-10.2), and serum phosphorus of 2.7 (reference value 2.5-4.5 mg/dl). Random urine potassium was 122.1 mEq/L, and intact parathyroid hormone was 144 pg/mL (reference value 14-65). His CT neck scan showed a 1.5 cm nodule inferior to the right thyroid lobe pole consistent with an inferior parathyroid adenoma. However, a parathyroid radionuclide scan using technetium-99m MIBI showed no radiopharmaceutical localization for parathyroid adenoma. Conclusion Hypercalcemia is extremely rare in Gitelman syndrome, offset by the action of concomitant hypomagnesemia. Our case shows the importance of investigating other causes of hypercalcemia, such as primary hyperparathyroidism in patients with Gitelman syndrome. To our knowledge, Gitelman syndrome and primary hyperparathyroidism are an extremely rare association that is present in our case. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m., Monday, June 13, 2022 12:48 p.m. - 12:53 p.m.

Acidified diet is not effective in preventing hypocalcemia in dairy cows on French commercial farms

The objective of this study was to assess, in the context of typical dairy farms in western France, the preventive effects of prepartum diet acidification (AcD) and mineral intake during late gestation on the incidence of subclinical hypocalcemia (SHC) and subclinical hypophosphatemia (SHP) after calving. We conducted a longitudinal study that followed a cohort of 371 Holstein cows from 26 French dairy farms; of these, 235 cows (15 farms) were supplied with anionic salts during late gestation, and 136 cows (11 farms) were not. Blood samples were collected from 1 to 22 cows per farm (average of 14.3 cows per farm) between 24 and 48 h after calving. Total calcium and inorganic phosphorus concentrations in plasma were then quantified by inductively coupled plasma - optical emission spectrometry. The effects of AcD on the incidence of SHC and SHP were assessed using mixed linear models that evaluated the cow-level factors parity, milk yield index, and individual health events/treatments, and the farm-level factors diet calcium and magnesium content, dietary phosphorus intake, vitamin D supply, diet crude protein content, and duration of AcD, with farm as a random effect. Approximately 55% of cows were diagnosed with SHC (calcium &amp;lt; 2.0 mmol/l, n = 203) and 37% with SHP (inorganic phosphorus &amp;lt; 1.3 mmol/l, n=136). The first model confirmed earlier findings that the risk of SHC is higher with increased parity (P ≤ 0.0001) and revealed a higher risk associated with high milk yield (P = 0.0005), high phosphorus intake (40–60 g/cow per day, OR = 3.5; ≥ 60 g/cow per day, OR = 7.3; P = 0.0003) and high vitamin D supply (≥ 19950 IU/cow per day, OR = 3, P = 0.007). The second model highlighted a greater risk of SHP with increasing parity (P = 0.03) and showed trends for the preventive effects of AcD (OR = 0.4, P = 0.07) and moderate amounts of phosphorus in the diet (OR = 0.4, P = 0.10). Overall, our results do not support the effectiveness of AcD in preventing SHC or SHP under field conditions examined here, probably resulting from insufficient diet acidification.

Ionized hypercalcemia in cats with azotemic chronic kidney disease (2012-2018).

BackgroundHypercalcemia is associated with chronic kidney disease (CKD) in cats, but studies assessing the physiologically relevant ionized calcium fraction are lacking.ObjectivesTo describe the prevalence and incidence rate of ionized hypercalcemia, and to explore predictor variables to identify cats at risk of ionized hypercalcemia in a cohort of cats diagnosed with azotemic CKD.AnimalsOne hundred sixty‐four client‐owned cats with azotemic CKD.MethodsVariables independently associated with ionized hypercalcemia at diagnosis of azotemic CKD were explored by binary logistic regression. Cats that were normocalcemic at diagnosis of azotemic CKD were followed over a 12‐month period or until ionized hypercalcemia occurred and baseline predictor variables for ionized hypercalcemia explored using Cox proportional hazards and receiver operating characteristic curve analysis.ResultsIonized hypercalcemia (median, 1.41 mmol/L; range, 1.38‐1.68) was observed in 33/164 (20%) cats at diagnosis of azotemic CKD and was associated with male sex, higher plasma total calcium and potassium concentrations, and lower plasma parathyroid hormone concentrations. Twenty‐five of 96 initially normocalcemic (26%) cats followed for minimum 90 days developed ionized hypercalcemia (median, 1.46 mmol/L; range, 1.38‐1.80) at a median of 140 days after diagnosis of azotemic CKD (incidence rate, 0.48 per feline patient‐year). Only body condition score was independently associated with incident ionized hypercalcemia.Conclusions and Clinical ImportanceThe occurrence of ionized hypercalcemia is high in cats with CKD. Continued monitoring of blood ionized calcium concentrations is advised.

Risk factors and implications associated with renal mineralization in chronic kidney disease in cats.

BackgroundNephrocalcinosis is a pathological feature of chronic kidney disease (CKD). Its pathophysiological implications for cats with CKD are unexplored.ObjectivesIdentify nephrocalcinosis risk factors and evaluate its influence on CKD progression and all‐cause mortality.AnimalsFifty‐one euthyroid client‐owned cats with International Renal Interest Society (IRIS) stages 2‐3 azotemic CKD.MethodsRetrospective cohort study. Histopathological kidney sections were assessed for nephrocalcinosis (von Kossa stain). Nephrocalcinosis severity was determined by image analysis (ImageJ). Ordinal logistic regressions were performed to identify nephrocalcinosis risk factors. The influence of nephrocalcinosis on CKD progression and mortality risk were assessed using linear mixed model and Cox regression, respectively. Cats were categorized by their owner‐reported time‐averaged phosphate‐restricted diet (PRD) intake, where PRD comprised ≥50%, 10‐50%, or none of food intake.ResultsNephrocalcinosis was rated as mild‐to‐severe in 78.4% and absent‐to‐minimal in 21.6% of cases. Higher baseline plasma total calcium concentration (tCa; odds ratio [OR] = 3.07 per 1 mg/dL; P = .02) and eating a PRD (10%‐50%: OR = 8.35; P = .01; ≥50%: OR = 5.47; P = .01) were independent nephrocalcinosis risk factors. Cats with absent‐to‐minimal nephrocalcinosis had increasing plasma creatinine (0.250 ± 0.074 mg/dL/month; P = .002), urea (5.06 ± 1.82 mg/dL/month; P = .01), and phosphate (0.233 ± 0.115 mg/dL/month; P = .05) concentrations over a 1‐year period, and had shorter median survival times than cats with mild‐to‐severe nephrocalcinosis.Conclusion and Clinical ImportanceHigher plasma tCa at CKD diagnosis and PRD intake are independently associated with nephrocalcinosis. However, nephrocalcinosis is not associated with rapid CKD progression in cats.

Effects of feeding different doses of 25-hydroxyvitamin D3 on the growth performance, blood minerals, antioxidant status and immunoglobulin of preweaning calves

The objective of this trial was to investigate the effects of feeding different doses of 25-hydroxyvitamin D3 (25(OH)D3) on the growth performance, blood minerals, vitamin D3 metabolites, antioxidant capacity and immunoglobulin of pre-weaned calves. In this experiment, eighteen Holstein calves (3.5 ± 1.24 days, average body weight: 40.68 ± 1.21 kg) were randomly assigned to 1 of 3 treatments (6 calves per group): the control group (0 IU 25(OH)D3 per calf per day), low-dose group (6000 IU 25(OH)D3 per calf per day) and high-dose group (12,000 IU 25(OH)D3 per calf per day). The 25(OH)D3 was mixed into the milk and offered to the calves. Calves fed 25(OH)D3 showed a linear increase in ADG (P = 0.013) and feed efficiency (P = 0.039) from 1 to 8 weeks, the withers height showed an improvement (P < 0.05) at 56 d. The plasma total calcium level tended to increase (P = 0.074) at 28 d and linearly increased (P = 0.012) at 56 d, and plasma 25(OH)D3 in calves linearly increased (P < 0.001) by feeding 25(OH)D3. The plasma total phosphorus content linearly increased (P = 0.003) at 56 d, but there was no difference in plasma total magnesium content by increasing feeding 25(OH)D3. Plasma growth hormone (P = 0.276) and insulin-like growth factor Ⅰ (P = 0.117) were not affected by treatment at 28 d, but growth hormone tended to increase (P = 0.058) and insulin-like growth factor Ⅰ linearly increased (P = 0.018) by increasing feeding 25(OH)D3 at 56 d. Plasma catalase (P < 0.05) and superoxide dismutase (P = 0.010) contents linearly increased by increasing feeding 25(OH)D3. Additionally, increasing 25(OH)D3 supplementation linearly increased (P < 0.05) the plasma immunoglobulin G concentration. In conclusion, the results indicated that feeding 25(OH)D3 (especially high dose of 25(OH)D3) could effectively improve growth performance, plasma minerals and hormones concentration and enhance the antioxidant capacity and immunoglobulin of calves. Feeding 25(OH)D3 is expected to be an effective means of promoting growth and maintaining the health of calves before weaning.

Poor performance of albumin or protein-adjusted plasma calcium to diagnose dyscalcemia in hospitalized patients: A confirmatory study in a general internal medicine department

IntroductionHypo- and hypercalcemia are common and some causes require urgent diagnosis and treatment. Measurement of ionized calcium is the reference test to diagnose calcium disorders but total calcium adjusted for protein or albumin concentration is more often used. MethodsPatients hospitalised in a general internal medicine department from September 2013 to December 2015 who had a total plasma calcium concentration and a serum albumin or protein concentration measured within 24h of a ionized calcium blood measurement were included. Total calcium was adjusted for protein or albumin concentration using widely used formulas and compared to ionized calcium as the gold standard. ResultsAmong 210 included patients, 46 (22%) had hypocalcemia, 124 (59%) normocalcemia and 40 (19%) hypercalcemia according to ionized calcium concentration. Total calcium had 50% sensitivity and 95% specificity to diagnose hypocalcemia and a 93% sensitivity and 89% specificity to diagnose hypercalcemia. Adjusting total calcium for protein or albumin concentrations did not increase and sometimes decreased diagnostic accuracy. ConclusionTotal calcium, with or without albumin/protein adjustment, is poorly sensitive to screen for hypocalcemia. Unadjusted total calcium is as sensitive as protein- or albumin-adjusted total calcium to screen for hypercalcemia. These data argue against the use of albumin- or protein-adjusted calcium. Ionized calcium measurement should be performed to confirm dyscalcemia in patients with abnormal total calcium concentration and to rule out hypocalcemia in patients with total calcium concentration in the lower range of normal values.

Biochemical reference intervals in broiler chickens according to age and strain

Abstract. The objective of the research was to study the physiological pattern of biochemical variables and to obtain reference intervals for young (less than 1 month) and adult (more than 1 month) broiler chickens of 2 strains. From the jugular vein, blood for analysis was collected, separated, and then immediately analyzed. The influence of age was significant for the majority of the investigated variables in the 2 groups. In Isa15 strain, a significant age-related decrease in plasma uric acid, glucose, cholesterol, triglycerides, phosphorus, potassium and iron was established. Also, a significant age-related increase in plasma calcium and ASAT was obtained in the same broiler strain. In Arbor Acres Plus strain, a significant age-related decrease in plasma glucose, cholesterol, triglycerides and phosphorus was observed. A significant age-related increase in plasma total protein, calcium and ASAT has also been reported in this broiler strain. A significant difference between the two strains was reported for plasma uric acid, glucose, cholesterol, phosphorus, magnesium and iron (p&lt;0.05). For most estimated parameters in the 2 strains, calculation of separate reference intervals for young and adult animals was appropriate. Except for potassium in young Isa15 strain, and phosphorus in young Arbor Acres Plus strain, all variables did not follow a normal distribution. Reference intervals are presented for both ages using non-parametric or robust method. 90% confidence intervals for both groups were calculated non-parametrically, or by the bootstraping method. The established reference intervals will be a useful guide for interpreting plasma biochemical variables in different strains of broiler chickens raised in Algeria, and reared in a mild Mediterranean climate.

Feline ureteral obstruction: a case-control study of risk factors (2016-2019).

Ureteral obstruction (UO) in cats causes acute kidney injury and typically requires surgical intervention. Information is required about potentially modifiable risk factors to inform prevention strategies. A case-control study was performed to assess risk factors associated with feline UO. Cases were defined as cats with either of the following: (1) ureteral obstruction (ureteroliths: 13/18; unknown: 5/18) confirmed with pyelography; or (2) a creatinine concentration >140 µmol/l with both UO (ureteroliths: 6/10; blood clots: 3/10; pyonephrosis: 1/10) and pyelectasia ⩾5 mm on abdominal ultra sonography. Controls were defined as cats without evidence of UO on history, physical examination and abdominal ultrasound. Age, sex, breed (domestic shorthair/longhair), diet (predominantly dry, mixed or predominantly moist food), housing (indoors or mixed) and plasma total calcium were evaluated for their association with UO using multivariable logistic regression. A receiver operator characteristic (ROC) curve was created to evaluate the predictive ability of the final model. In total, 168 cats (28 cases, 140 controls) were included. Age, sex, breed, housing and total calcium were not significantly associated with UO; however, diet was. Compared with cats eating a predominantly moist food diet, cats fed a predominantly dry food diet were 15.9 times more likely to develop a UO (95% confidence interval 2.9-295; P = 0.009). There was no difference in the association between diet and UO in cats fed a mixed diet vs cats fed a predominantly moist food diet (P = 0.25). The area under the ROC curve was 72%. Changes in diet formulation could provide a simple and economical method to reduce the risk of UO.

MO1020EFFICACY OF CALCITRIOL COMPARING TO ALFACALCIDOL FOR THE TREATMENT OF SECONDARY HYPERPARATHYROIDISM IN CHILDREN ON PERITONEAL DIALYSIS

Abstract Background and Aims Active vitamin D analogues are used routinely for the treatment of secondary hyperparathyroidism in children with end-stage renal disease (ESRD) on peritoneal dialysis (PD). Calcitriol is preferred active form of vitamin D, while data on efficacy of alfacalcidol in children on PD are limited. The aim of this study was to compare the efficacy of these two active vitamin D analogues for the treatment of secondary hyperparathyroidism in children on PD. Method This retrospective cohort study included data from 26 pediatric patients under 18 years of age with ESRD on PD who were treated at the National Research Center for Maternal and Child Health, Astana, Kazakhstan. Patients were allocated by initial treatment into two groups: oral alfacalcidol (n=21) and oral calcitriol (n=5). The first step of the study was to compare the efficacy of treatment between this two groups 3 and 6 months after. The second step was to compare the efficacy of calcitriol in subgroup of patients from alfacalcidol group who were switched to calcitriol later (n=12). The following characteristics were analyzed: parathyroid hormone (PTH), total plasma calcium, ionized plasma calcium, plasma phosphorus, initial dose of active vitamin D and corrected dose of vitamin D after 3 months. Independent t-test and repeated measures Anova were used for comparison between alfacalcidol and calcitriol groups. To compare data in subgroup between baseline and 3 months after conversion from alfacalcidol to calcitriol we used paired Student t-test. Results The mean age and baseline characteristics were no different between alfacalcidol and calcitriol groups (Table 1). The initial dose of alfacalcidol was 2.42±1.03 µg/week (0.157±0.097 µg/kg/week) and 2.09±0.74 µg/week (0.105±0.039 µg/kg/week) for calcitriol were not significantly different (P=0.5 and P=0.25 respectively). After 3 months of treatment there was statistically significant decrease of PTH level in calcitriol group 180±168 pmol/L comparing to alfacalcidol group 869±670 pmol/L (P=0.006). After 6 months, there was statistically significant decrease of PTH level in calcitriol group 261±259 pmol/L in contrast with alfacalcidol group 1080±716 pmol/L (P=0.047) and rise in total calcium in calcitriol group 2.46±0.17 mmol/L compared with alfacalcidol group 2.09±0.25mmol/L (P=0.035). The mean dose of calcitriol was also significantly lower as opposed to alfacalcidol dose: 0.04±0.039 µg/kg/week and 0.17±0.076 µg/kg/week respectively (P=0.002). The median age of children who were switched from alfacalcidol to calcitriol were significantly younger comparing with those who continued alfacalcidol (5±4.6 and 10±4.3 years of age respectively (P=0.022)). 3 months after conversion there was significant increase in ionized calcium level and decrease in PTH level comparing with baseline (Table 2). The dose of alfacalcidol before and dose of calcitriol after switch were differed (0.18±0.1 µg/kg/week and 0.13±0.05 µg/kg/week respectively, P=0.025) Conclusion Calcitriol showed superior efficacy for the treatment of secondary hyperparathyroidism in children on PD with the dose 4.25 times lower that of alfacalcidol. Alfacalcidol had limited efficacy for the treatment of secondary hyperparathyroidism in younger children when prescribed in recommended doses.

The effect of oral calcium boluses at parturition on blood metabolites and milk yield in grazing Holstein cattle

The objective of this study was to assess the effect of oral calcium boluses at parturition on plasma total calcium (tCa), phosphorus (P), total magnesium (tMg), beta hydroxybutyrate (BHB) and milk yield during the postpartum (pp) of grazing Holstein cows. The study was conducted on a seasonal grazing dairy in Chile. Prepartum cows were fed an anionic diet (-86 mEq/kg DM). In 2019, 10 cows of parity 2, 3, and ≥ 4, respectively, were randomly assigned at parturition to a treatment group (n=30), receiving 2 boluses of oral Ca, (CaCl2, providing 44 g Ca) 24 h apart, and matched by parity to a control group (n=30). A blood sample was obtained at d 1, 2, 3, 4 and 7 pp. Milk yield was recorded until 30 d pp. Minerals and milk yield were analysed by ANOVA for repeated measures. Treatment had no effect on tCa in parity 2 cows. However, in lactation 3, Ca supplementation increased the concentration of tCa at d 2 and 3 pp, and in lactation ≥ 4 boluses tended to increase tCa at d 2 pp. Higher BHB concentrations at d 4 pp were found in treated cows than in the control cows. Milk yield in lactation 2 was lower in the treated than the control group. In lactations ≥ 3, milk yield was higher in the treated than the control group. In conclusion, two oral Ca boluses at parturition 24 h apart in grazing cattle fed anionic prepartum diets, improved Ca status and milk yield during the postpartum period in cows ≥ 3 lactations.

Changes in the Relationship between Ionized and Total Calcium in Clinically Healthy Dairy Cows in the Period around Calving.

Simple SummaryHypocalcemia is a widespread problem in dairy cows in the first days after calving, which increases the risk for secondary diseases. In practice, the measurement of total blood serum or plasma calcium is widely used to diagnose hypocalcemia. The present study demonstrates a high discrepancy between total and ionized calcium specifically around calving, suggesting that only ionized calcium provides an accurate indication of the animal’s calcium status during that period. We developed an optimized model for prediction of ionized calcium from total calcium, non-esterified fatty acids, beta-hydroxybutyric acid, cholesterol, and phosphorous. However, the precision of that model is still unsatisfactory.We aimed to establish a model for prediction of iCa from tCa, using multivariable regressions with diverse blood constituents. Blood was taken from 14 cows at days −2, 0, 2, 4, 7, and 14 relative to parturition. Cows were clinically healthy, and no hypocalcaemia prophylaxis and treatment were applied. Total calcium and further parameters were determined from frozen serum. Ionized calcium, blood gases, and electrolytes were determined from heparin-stabilized blood samples. Linear regression between iCa and tCa was estimated. Precision improved only slightly using a multivariable model. Best precision was achieved when estimating the iCa:tCa ratio from other blood constituents. To identify the reason behind the poorly predictive value of tCa for iCa, the relative changes of iCa and tCa around calving were calibrated to the respective values of day −2 (=100%) for each cow. An increase in the iCa:tCa ratio was observed from 0.43 at day −2 to 0.48 at day 0, followed by a gradual decrease towards 0.43 at day 7. We conclude that routine measurement of iCa should be implemented in the diagnosis of hypocalcaemia. An optimized estimate of iCa from tCa with non-esterified fatty acids (NEFA), beta-hydroxybutyric acid, cholesterol, and phosphorous as co-predictors is still poorly satisfying.

Performance specifications for measurement uncertainty of common biochemical measurands according to Milan models.

Definition and fullfillment of analytical performance specifications (APS) for measurement uncertainty (MU) allow to make laboratory determinations clinically usable. The 2014 Milan Strategic Conference have proposed models to objectively derive APS based on: (a)the effect of analytical performance on clinical outcome; (b)biological variation components; and (3) the state of the art of the measurement, defined as the highest level of analytical performance technically achievable. Using these models appropriately, we present here a proposal for defining APS for standard MU for some common biochemical measurands. We allocated a group of 13 measurands selected among the most commonly laboratory requested tests to each of the three Milan models on the basis of their biological and clinical characteristics. Both minimum and desirable levels of quality of APS for standard MU of clinical samples were defined by using information obtained from available studies. Blood total hemoglobin, plasma glucose, blood glycated hemoglobin, and serum 25-hydroxyvitamin D3 were allocated to the model 1 and the corresponding desirable APS were 2.80, 2.00, 3.00, and 10.0%, respectively. Plasma potassium, sodium, chloride, total calcium, alanine aminotransferase, creatinine, urea, and total bilirubin were allocated to the model 2 and the corresponding desirable APS were 1.96, 0.27, 0.49, 0.91, 4.65, 2.20, 7.05, and 10.5%, respectively. For C-reactive protein, allocated to the model 3, a desirable MU of 3.76% was defined. APS for MU of clinical samples derived in this study are essential to objectively evaluate the reliability of results provided by medical laboratories.

Beneficial effects of substituting soybean meal for white lupin (Lupinus albus, cv. Zulika) meal on the biochemical blood parameters of laying hens

The experiment aimed to determine the effect of substituting 50% of soy protein for lupin protein in feed mixtures intended for the nutrition of high-yield Isa Brown laying hens, on selected biochemical blood plasma indicators. The trial was designed as a long-lasting feeding experiment (51 weeks) and involved a total of 180 hens divided in three experimental groups (control group C and experimental groups WLS and WDLS). At the end of the laying cycle, blood samples were taken from the hens by puncture of the vena basilica and subsequently, the required blood plasma indicators were analysed in the laboratory. The results demonstrated that the long-term feeding of white lupin (variety Zulika) did not affect the molar concentration of plasma inorganic phosphorus (P), magnesium (Mg), sodium (Na), potassium (K), chloride (Cl), uric acid (UAC) and the activity of alanine aminotransferase (AST). By contrast, the substitution of soy protein for lupin protein in the diets of the experimental groups of laying hens led to the statistically significant (p ≤ .05) decrease of total plasma protein (TP), total cholesterol (Chol), calcium (Ca) and triacylglycerides (TAG) and to an increase (p ≤ .05) of alkaline phosphatase activity (ALP). Highlights Replacement of soya protein with white lupin protein reduced cholesterol and triacylglycerides in blood plasma Feedstuff including white lupin protein did not affect negatively the health status of the layers