Low Potassium Research Articles

A randomized controlled trial evaluating the effect of providing a rest period during long-distance transportation of surplus dairy calves: Part II. Effect on hematological variables

The objective of this randomized controlled trial was to determine if providing a rest stop including provision of feed and water between periods of continuous transportation mitigates the effect of long-distance transportation on markers of energy status and hydration in calves transported by road for 16 h. This study was conducted between September 2022 to January 2023 and included male and female Holstein and crossbred dairy calves ≥7 d old from 2 commercial dairy farms in Ontario, Canada (n = 96). On the day before transportation, calves were enrolled and randomly assigned to one of 2 treatment groups: (1) continuous transportation by road for 16 h or (2) 8 h of transport, 8 h of rest, and a further 8 h of transport to a single calf-raising facility. Calves that received a rest stop were fed 2 L of milk replacer at the time of unloading for the rest period and again immediately before reloading for the second leg of the journey. Blood samples were collected before and after transportation as well as daily for 3 d following arrival to the calf-raising facility. Serum was analyzed for concentrations of BHB, nonesterified fatty acids (NEFA), haptoglobin, and creatine kinase, and acid-base disturbances were evaluated within 1 h of collection of whole blood to assess glucose, sodium, potassium, ionized calcium, hematocrit, hemoglobin, pH, base excess, partial pressure of oxygen, total carbon dioxide, bicarbonate, partial pressure of carbon dioxide, and oxygen saturation. Mixed linear regression models with repeated measures were built to assess the effect of treatment group, age at transportation, breed, and sex on these parameters. Immediately after transportation, calves that received the rest period had lower BHB (-68.04 μmol/L, 95% CI: -99.59 to -36.49), NEFA (-0.14 mmol/L, 95% CI -0.22 to -0.07), and sodium (-1.10 mmol/L, 95% CI = -2.18 to -0.02), and higher glucose (0.48 mmol/L, 95% CI = 0.21 to 0.74), potassium (0.27 mmol/L, 95% CI = 0.11 to 0.43), ionized calcium (0.06 mmol/L, 95% CI = 0.03 to 0.08), and oxygen saturation (8.76%, 95% CI = 1.61 to 15.91) compared with calves that were continuously transported for 16 h. Additionally, calves transported between 11 and 12 d old had lower hematocrit (-1.22%, 95% CI = -2.19 to -0.25), hemoglobin (-3.07 g/L, 95% CI = -5.70 to -0.43), haptoglobin (-0.13 g/L, 95% CI = -0.23 to -0.02), and potassium (-0.13 mmol/L, 95% CI = -0.22 to -0.04) and higher sodium (0.83 mmol/L, 95% CI = 0.03 to 1.63) than 7 to 8 d old calves. Furthermore, calves that were 13 to 24 d old at transport had lower haptoglobin (-0.16 g/L, 95% CI = -0.27 to -0.06) and potassium (-0.14 mmol/L, 95% CI = -0.23 to -0.05), and higher sodium (1.02 mmol/L, 95% CI = 0.22 to 1.82) and ionized calcium (0.02 mmol/L, 95% CI = 0.002 to 0.035) compared with calves transported at 7 to 8 d old. The results of this trial demonstrate that a rest period improves energy status upon arrival to a calf-raising facility, suggesting that the benefit of a rest period may be mostly related to the provision of mid-journey milk meals.

Effects of different treatment modalities on cardiovascular disease in ARR-positive hypertensive patients.

Data on the prognosis of clinically undiagnosed hypertensive patients who are aldosterone-to-renin ratio (ARR) positive are still scarce. Therefore, we investigated the clinical characteristics of clinically undiagnosed hypertensive patients who were ARR-positive and the influence of their different treatments on the occurrence and development of complications. A total of 285 hypertensive patients data with ARR ≥ 3.8 in the Second People's Hospital of Huai'an from January 2019 to December 2021 were collected, and 135 undiagnosed hypertensive patients were ultimately included in the analysis. According to their treatment strategy in various clinical departments, 135 patients were divided into the operation, spironolactone and control groups. Then, the clinical characteristics and the occurrence and development of complications in the three groups were compared. The results suggested that: (1) Only 34 (11.9%) of 285 hypertensive patients with ARR ≥ 3.8 were clearly diagnosed with Primary aldosteronism (PA) through functional tests, and the blood pressure (BP) compliance rate was only 50.30% during follow-up. (2) Based on exclusion criteria, 135 undiagnosed hypertensive patients were eventually included in the analysis. Patients in the surgery group had lower blood potassium levels and higher aldosterone levels than those in the other two groups, and their risk of new cerebrovascular complications was lower than that of the patients in the spironolactone group. (3) The risk of new cerebrovascular complications in the spironolactone group was 9.520 times higher than that of the control group, and this risk mainly occurred in patients with ARR values of 3.8-5.7. On the whole, surgery remains a good option for hypertensive patients with severe hyperaldosteronism and hypokalemia and those unable to undergo confirmatory tests; however, spironolactone therapy in patients with clinically undiagnosed hypertension, especially those with 3.8 ≤ ARR < 5.7, confered a higher risk of new cerebrovascular complications.

Taste Preference for Salt Predicts Salt Intake in a Chinese Population.

This study describes the association between taste preference for salt and actual salt intake, thus guiding and refining personal and public health campaigns designed to lower salt intake in China. A cross-sectional survey of 1489 residents aged 18 to 69 years was conducted in 2017 in China. A multistage random sampling strategy was used, and a combination of questionnaires and physical and laboratory measurements were conducted to collect baseline characteristics and knowledge, attitudes, and behavior (KAB) related to salt. A 24 h urine collection was obtained for sodium and potassium excretion analysis. Participants were divided into two groups, light taste preference and salty taste preference, according to their answer to the question "Compared to others, how do you think your taste preference is for salt?". The mean age of the 1489 participants was 46.26 years, 48.9% were males, over 1/3 (35.7%) were identified as hypertensive, and 317 (21.3%) self-reported a salty taste preference. The mean of 24 h urinary sodium excretion was 167.32 mmol/24 h, corresponding to 9.79 g salt/d intake, and the sodium-to-potassium ratio (Na/K) was 4.90. The 24 h urinary sodium excretion of salty taste preference (177.06 mmol/24 h) was significantly higher than that of light taste preference (164.69 mmol/24 h). The multiple logistic regression analysis showed that the salty taste preference group had significantly higher 24 h urinary sodium (ORa(95%CI) = 1.004(1.002-1.006)), diastolic blood pressure (DBP), proportion of greasy food preference, and drinking levels, but lower potassium excretion, response levels to most KAB questions, and regular physical activity compared to the light taste preference group. Self-reported taste preference for salt predicted actual salt intake, which was verified by 24 h urinary sodium monitoring. Taste preference for salt could be used as a proxy for intake in terms of targeted salt intake, nutrition, and health education.

Exogenous regulation of macronutrients promotes the accumulation of alkaloid yield in anisodus tanguticus (Maxim.) pascher

BackgroundAnisodus tanguticus (Maxim.) Pascher (A. tanguticus) is a valuable botanical for extracting tropane alkaloids, which are widely used in the pharmaceutical industry. Implementing appropriate cultivation methods can improve both the quality and yield of A. tanguticus. A two-year field experiment was conducted from 2021 to 2023 using a single-factor randomized complete block design replicated three times. The study examined the effects of different nutrient levels (nitrogen: 0, 75, 150, 225, 300, 375 kg/ha; phosphorus: 0, 600, 750, 900, 1050, 1200 kg/ha; potassium: 0, 75, 112.5, 150, 187.5, 225 kg/ha) on the growth, primary alkaloid contents, and alkaloid yield of A. tanguticus at different growth stages (S-Greening, S-Growing, S-Wilting; T-Greening, T-Growing, and T-Wilting) in both the roots and aboveground portions.ResultsOur results demonstrate that nutrient levels significantly affect the growth and alkaloid accumulation in A. tanguticus. High nitrogen levels (375 kg/ha) notably increased both root and aboveground biomass, while phosphorus had a minimal effect, especially on aboveground biomass. For alkaloid content (scopolamine, anisodamine, anisodine, atropine), a moderate nitrogen level (225 kg/ha) was most effective, followed by low potassium (75 kg/ha), with phosphorus showing a limited impact. Increased phosphorus levels led to a decrease in scopolamine content. During the T-Growing period, moderate nitrogen addition (225 kg/ha) yielded the highest alkaloid levels per unit area (205.79 kg/ha). In the T-Wilting period, low potassium (75 kg/ha) and low phosphorus (750 kg/ha) resulted in alkaloid levels of 146.91 kg/ha and 142.18 kg/ha, respectively. This indicates nitrogen has the most substantial effect on alkaloid accumulation, followed by potassium and phosphorus. The Douglas production function analysis suggests focusing on root biomass and the accumulation of scopolamine and atropine in roots to maximize alkaloid yield in A. tanguticus cultivation.ConclusionsOur findings show that the optimum harvesting period for A. tanguticus is the T-Wilting period, and that the optimal nitrogen addition is 225 kg/ha, the optimal potassium addition is 75 kg/ha, and the optimal phosphorus addition is 600 kg/ha or less.

Home blood pressure measurement days and changes in urinary sodium-to-potassium ratio, estimated salt and potassium intakes and blood pressure: 1-year prospective study.

Current international guidelines recommend home blood pressure (BP) measurement and low sodium and high potassium intakes for the management of hypertension. We hypothesized that increased home BP measurement may result in more effective management of sodium and potassium intakes and BP. We examined associations of home BP measurement days with changes in the urinary sodium-to-potassium (Na/K) ratio, estimated salt and potassium intakes and BP. We included 209 healthy participants (mean age, 55.9 years; 56.5% women) from a prospective cohort study. We examined 1-year data on self-measured home BP and spot urine samples. Median (interquartile range) days of home BP measurement was 324 (225-358) over 1-year. Baseline mean (SD) Na/K ratio, salt and potassium intakes, morning and evening SBP, and morning and evening DBP were 3.8 (2.3), 8.5 (1.9) g/day, 1833.5 (416.5) mg/day, 120.4 (14.0) mmHg, 118.2 (14.2) mmHg, 79.2 (10.1) mmHg, and 76.2 (10.1) mmHg, respectively. In multivariable-adjusted linear regression , β (standard error) per 10 days increase in number of home BP measurement were -0.031 (0.017) for Na/K ratio, -0.036 (0.015) for salt intake, -1.357 (2.797) for potassium intake, -0.178 (0.064) for morning SBP, -0.079 (0.041) for morning DBP, -0.109 (0.067) for evening SBP and -0.099 (0.045) for evening DBP. Additionally, relationships persisted for men and women, but changes in salt intake were more pronounced among participants taking antihypertensive medication (interaction P = 0.002). Continuous measurement of home BP may lead not only to self-monitoring of BP, but also to declines in salt intakes and some BP indices.

Dietary salt intake and kidney function in rural Senegalese populations: a cross-sectional study

IntroductionHigh salt intake is a major risk factor for hypertension and its complications such as chronic kidney disease (CKD) and cardiovascular diseases. The present study aimed to determine level of sodium consumption and its relation with kidney function in the rural populations of Ferlo (centre of Senegal).Subjects and methodsWe performed a cross-sectional study including 400 volunteers aged > 18 years. Clinical, biological and dietary data were collected during household visits. Daily sodium intake was measured in the 24 h-urine outpout and CKD was defined as eGFR < 60 ml/min. Linear regression analysis was used to assess association between sodium intake and covariates.ResultsMean age was 46.42 ± 15.60 and sex-ratio was 1.05. Prevalence of hypertension, CKD and overweight were 21.5, 11.7 and 20.5%, respectively. The median daily salt intake was 11.7 g with interquartile range of 14.8 g. Only 11.25% of participants consumed less than 5 g/day. After multivariate analysis, high salt intake was associated with age > 60 years, overweight and CKD. However, gender and hypertension were not significantly associated with salt intake. Industrial broths (91.5%) and bread (85%) represented the main sources of dietary salt.ConclusionThis study revealed high levels of daily salt intake contrasting with low potassium intakes in the majority of participants. Participants with CKD, overweight and age > 60 years presented higher salt consumption. Stategies to reduce salt consumption are urgently needed to reduce burden of CKD in rural Senegalese populations.

Sodium and potassium excretion and its association with cardiovascular disorders in Mexican adults.

Worldwide, as well as in Mexico, the leading cause of death is cardiovascular disease (CVD). Hypertension is the main risk factor for CVD; about 50% of the adult population suffers from this condition. High sodium (Na) intake combined with low potassium (K) intake can trigger cardiovascular disorders such as high blood pressure (BP). The aim of this study was to estimate the mean excretion of Na and K in Mexican adults using a spot urine sample, and its association with cardiovascular disorders. Information on 2,778 adults, 20-59 years of age, who participated in ENSANUT-2016 was analyzed. Na and K were estimated using Tanaka formulae. Biomarkers such as glucose, total cholesterol, triglycerides, HDL cholesterol and LDL cholesterol, and anthropometry were measured. Mean Na was 3,354 mg/day (95%CI: 3,278, 3,429), 1,440 mg/day of K (95%CI: 1,412, 1,469), and the Na-K ratio was 2.4. The excretion of Na was greater in adults with high BP (3,542 mg/day) compared to those with normal BP (3,296 mg/day). In adults with hypertension, excretion of K was 10% greater (1,534 mg/day) than in adults with normal BP (1,357 mg/day). In adults with moderate reduction of renal function, Na excretion was 22% less (2,772 mg/day) than in adults with normal kidney function (3,382 mg/day). The results of this study show that the cardiovascular health of Mexican adults is at risk, as they showed high Na excretion and low K excretion.

Low potassium activation of proximal mTOR/AKT signaling is mediated by Kir4.2

The renal epithelium is sensitive to changes in blood potassium (K+). We identify the basolateral K+ channel, Kir4.2, as a mediator of the proximal tubule response to K+ deficiency. Mice lacking Kir4.2 have a compensated baseline phenotype whereby they increase their distal transport burden to maintain homeostasis. Upon dietary K+ depletion, knockout animals decompensate as evidenced by increased urinary K+ excretion and development of a proximal renal tubular acidosis. Potassium wasting is not proximal in origin but is caused by higher ENaC activity and depends upon increased distal sodium delivery. Three-dimensional imaging reveals Kir4.2 knockouts fail to undergo proximal tubule expansion, while the distal convoluted tubule response is exaggerated. AKT signaling mediates the dietary K+ response, which is blunted in Kir4.2 knockouts. Lastly, we demonstrate in isolated tubules that AKT phosphorylation in response to low K+ depends upon mTORC2 activation by secondary changes in Cl- transport. Data support a proximal role for cell Cl- which, as it does along the distal nephron, responds to K+ changes to activate kinase signaling.

Genome-Wide Identification, Characterization, and Expression of the HAK/KUP/KT Potassium Transporter Gene Family in Poncirus trifoliata and Functional Analysis of PtKUP10 under Salt Stress

Potassium is an essential mineral nutrient for citrus growth and stress response. In this study, the HAK/KUP/KT gene family was identified from the genome of trifoliate orange (Poncirus trifoliata). The physical and chemical properties, chromosomal location, gene structure, evolutionary relationship, conserved motifs, and tissue expression characteristics were analyzed. The expression characteristics under low potassium and salt stress were analyzed by fluorescence quantitative PCR. The function of PtKUP10 was investigated by heterologous expression in Arabidopsis thaliana. The results showed that at least 18 PtKUPs were distributed in seven chromosomes. Phylogenetic analysis showed that four PtKUPs clustered in clade I, which mediated the high-affinity potassium absorption. Gene expression analysis showed that four PtKUPs were highly expressed in root, seven PtKUPs were up-regulated by low potassium stress, and nine PtKUPs were up-regulated by salt stress. The cis-acting elements on the promoter of PtKUPs were predominantly involved in stress and hormone responses. Overexpression of PtKUP10 in Arabidopsis thaliana could enhance salt tolerance by accumulating more potassium in the shoot and reducing sodium content in the shoots and roots. These results indicated that PtKUPs play important roles in potassium absorption and salt stress response, and PtKUP10 might enhance salt tolerance by maintaining potassium and sodium homeostasis.

Association between spot urinary sodium-to-potassium ratio and blood pressure among Chinese adults aged 18-69 years: the SMASH study.

Excessive sodium and low potassium intake are involved in the development of hypertension. Growing evidence showed that the sodium-to-potassium ratio (Na/K) was significantly associated with blood pressure (BP). However, studies on the dose-response relationship of spot urinary Na/K ratio with hypertension and BP in the general population are scarce, especially in the Chinese population. Data from the post-intervention survey of the Shandong Ministry of Health Action on Salt and Hypertension (SMASH) project was analyzed. Associations between Na/K molar ratio and hypertension prevalence and between Na/K molar ratio and BP indices were analyzed using multivariable logistic and linear regression, respectively, followed by subgroup analysis and interaction analysis. The restricted cubic spline model was used to explore the dose-response relationship. Informed by existing literature, we adjusted for potential confounding factors, including temperature and renal function, to assess the association and dose-response relationship. There was a non-linear positive association between Na/K and hypertension (OR:1.09, 95%CI: 1.08-1.11) and a linear positive association between Na/K and systolic BP, diastolic BP, and mean arterial pressure (β 0.53, 95%CI: 0.45-0.60; β 0.36, 95%CI: 0.31-0.41; and β 0.42, 95%CI: 0.36-0.47, respectively). The association was stronger in individuals with hypertension, female patients, those in the 50-59-year age group, and those who were obese. Environmental temperatures had little impact on associations. Our findings provide further evidence that the spot urinary Na/K ratio is a simple, useful, and convenient indicator for monitoring salt reduction and potassium increase, which could be used in clinical and public health practices.

The 14-3-3 protein nt GF14e interacts with CIPK2 and increases low potassium stress in tobacco

ABSTRACT Potassium (K+) plays a role in enzyme activation, membrane transport, and osmotic regulation processes. An increase in potassium content can significantly improve the elasticity and combustibility of tobacco and reduce the content of harmful substances. Here, we report that the expression analysis of Nt GF14e, a 14-3-3 gene, increased markedly after low-potassium treatment (LK). Then, chlorophyll content, POD activity and potassium content, were significantly increased in overexpression of Nt GF14e transgenic tobacco lines compared with those in the wild type plants. The net K+ efflux rates were severely lower in the transgenic plants than in the wild type under LK stress. Furthermore, transcriptome analysis identified 5708 upregulated genes and 2787 downregulated genes between Nt GF14e overexpressing transgenic tobacco plants. The expression levels of some potassium-related genes were increased, such as CBL-interacting protein kinase 2 (CIPK2), Nt CIPK23, Nt CIPK25, H+-ATPase isoform 2 a (AHA2a), Nt AHA4a, Stelar K+ outward rectifier 1(SKOR1), and high affinity K+ transporter 5 (HAK5). The result of yeast two-hybrid and luciferase complementation imaging experiments suggested Nt GF14e could interact with CIPK2. Overall, these findings indicate that NtGF14e plays a vital roles in improving tobacco LK tolerance and enhancing potassium nutrition signaling pathways in tobacco plants.

Association between the preprocedural serum potassium level and atrial fibrillation recurrence after catheter ablation

BackgroundThe association between serum potassium and atrial fibrillation (AF) recurrence after catheter ablation remains unclear. ObjectiveThe purpose of this study was to investigate whether preprocedural serum potassium level influences AF recurrence in patients who underwent catheter ablation. MethodsWe used data of patients with AF who underwent de novo catheter ablation from the prospective Chinese Atrial Fibrillation Registry Study. Patients with prior ablation and without baseline serum potassium were excluded. The primary outcome was 1-year AF recurrence after a 3-month blanking period from the ablation procedure. Restricted cubic spline and Cox proportional models were used to compare outcomes across serum potassium groups. ResultsA total of 4838 patients with AF who underwent de novo catheter ablation was enrolled. At 1 year, AF recurrence occurred in 1347 patients (27.8%). The relationship between preprocedural serum potassium levels and 1-year AF recurrence after ablation presented as U shape (P for nonlinear = .048). Compared with the group of serum potassium within 4.41–4.60 mmol/L, the risk of AF recurrence increased significantly in the lowest serum potassium group (≤4.00 mmol/L) after multivariable analysis (hazard ratio [HR] 1.26; 95% confidence interval 1.06–1.51; P = .010). Other groups with lower or higher serum potassium levels including 4.01–4.20 mmol/L (HR 1.18), 4.21–4.40 mmol/L (HR 1.16), 4.61–4.80 mmol/L (HR 1.07), and ≥4.81 mmol/L (HR 1.11) showed nonsignificant higher recurrence risk. ConclusionThe relationship between preprocedural potassium and AF recurrence was U shaped, with an optimal potassium range (4.41–4.60 mmol/L). Lower potassium level is associated with increased AF recurrence risk after catheter ablation.

Effect of the DASH diet on the sodium-chloride cotransporter and aquaporin-2 in urinary extracellular vesicles.

The dietary approach to stop hypertension (DASH) diet combines the antihypertensive effect of a low sodium and high potassium diet. In particular, the potassium component of the diet acts as a switch in the distal convoluted tubule to reduce sodium reabsorption, similar to a diuretic but without the side effects. Previous trials to understand the mechanism of the DASH diet were based on animal models and did not characterize changes in human ion channel protein abundance. More recently, protein cargo of urinary extracellular vesicles (uEVs) has been shown to mirror tissue content and physiological changes within the kidney. We designed an inpatient open label nutritional study transitioning hypertensive volunteers from an American style diet to DASH diet to examine physiological changes in adults with stage 1 hypertension otherwise untreated (Sacks FM, Svetkey LP, Vollmer WM, Appel LJ, Bray GA, Harsha D, Obarzanek E, Conlin PR, Miller ER 3rd, Simons-Morton DG, Karanja N, Lin PH; DASH-Sodium Collaborative Research Group. N Engl J Med 344: 3-10, 2001). Urine samples from this study were used for proteomic characterization of a large range of pure uEVs (small to large) to reveal kidney epithelium changes in response to the DASH diet. These samples were collected from nine volunteers at three time points, and mass spectrometry identified 1,800 proteins from all 27 samples. We demonstrated an increase in total SLC12A3 [sodium-chloride cotransporter (NCC)] abundance and a decrease in aquaporin-2 (AQP2) in uEVs with this mass spectrometry analysis, immunoblotting revealed a significant increase in the proportion of activated (phosphorylated) NCC to total NCC and a decrease in AQP2 from day 5 to day 11. This data demonstrates that the human kidney's response to nutritional interventions may be captured noninvasively by uEV protein abundance changes. Future studies need to confirm these findings in a larger cohort and focus on which factor drove the changes in NCC and AQP2, to which degree NCC and AQP2 contributed to the antihypertensive effect and address if some uEVs function also as a waste pathway for functionally inactive proteins rather than mirroring protein changes.NEW & NOTEWORTHY Numerous studies link DASH diet to lower blood pressure, but its mechanism is unclear. Urinary extracellular vesicles (uEVs) offer noninvasive insights, potentially replacing tissue sampling. Transitioning to DASH diet alters kidney transporters in our stage 1 hypertension cohort: AQP2 decreases, NCC increases in uEVs. This aligns with increased urine volume, reduced sodium reabsorption, and blood pressure decline. Our data highlight uEV protein changes as diet markers, suggesting some uEVs may function as waste pathways. We analyzed larger EVs alongside small EVs, and NCC in immunoblots across its molecular weight range.

Chemical constraints and tectonic setting of the Ginebra ophiolite complex

The occurrence and types of ophiolites in the Central Cordillera of the Colombian Andes have not been identified in terms of their tectonic settings and geochemical features. Therefore, the study of the tectonic setting and subduction zones in the ophiolites’ magmatic evolution becomes a significant issue. The Ginebra Ophiolitic Complex (GOC) is located on the western flank of the Central Cordillera in the Valle del Cauca Department, southwest of Colombia, assigned to the Lower Cretaceous period, as indicated by the contact of the GOC with the Buga Batholith. The GOC is formed by three main lithologies: amphibolite, gabbro, and ultramafic rocks (pyroxenite and peridotite), according to Ossa (2007). The rocks in the Puente Piedra section, located in the northeast of Ginebra municipality, are part of the gabbroic cumulates within the ophiolitic sequence. This sequence comprises interspersed layers of gabbroic cumulates, gabbrodiorites, and diorites; interpreted as a result of crystal accumulation and fractional crystallization processes. The mafic rocks of the GOC are sub-alkaline and correspond to the low potassium (K2O wt% 0.03-0.06) tholeiitic series. Geochemically, they have SiO2 wt% ranging from 49 to 61 and an aluminum oxide saturation index of approximately ~0.4 and ~0.8, indicating a metaluminous type. The geochemistry of the studied rocks from Puente Piedra section indicates that the GOC formed through fractional crystallization and accumulation processes from a single magma source. Cluster analysis, used to compare the geochemistry of GOC rocks and the Amaime Complex basalts, suggests a similar magma source, possibly linked to multiple recharge events that underwent fractional crystallization, melt extraction, and accumulation processes. The geochemical parameters are indicative of a suprasubduction zone ophiolite, characterized by a low potassium tholeiitic series affinity, TiO2 values typically &lt;1.2 wt%, Th enrichment typical of subduction zones, high Pb content, and low values of Ti, Y, Yb, Ta, Nb, Zr, and Hf.

Hemodynamic effects of low versus high dialysate bicarbonate concentration in hemodialysis patients.

Hemodialysis treatment using standard dialysate bicarbonate concentrations cause transient metabolic alkalosis possibly associated with hemodynamic instability. The aim of this study was to perform a detailed comparison of high and low dialysate bicarbonate in terms of blood pressure, intradialytic hemodynamic parameters, orthostatic blood pressure, and electrolytes. Fifteen hemodialysis patients were examined in a single-blind, randomized, controlled, crossover study. Participants underwent a 4-h hemodialysis session with dialysate bicarbonate concentration of 30 or 38 mmol/L with 1 week between interventions. Blood pressure was monitored throughout hemodialysis, while cardiac output, total peripheral resistance, stroke volume, and central blood volume were assessed with ultrasound dilution technique (Transonic). Orthostatic blood pressure was measured pre- and post-hemodialysis. With similar ultrafiltration (UF) volume (2.6 L), systolic blood pressure (SBP) tended to decrease more during high dialysate bicarbonate compared to low dialysate bicarbonate; the mean (95% confidence interval) between treatment differences in SBP were: 8 (-4; 20) mmHg (end of hemodialysis) and 7 (0; 15) mmHg (post-hemodialysis). Stroke volume decreased whereas total peripheral resistance increased significantly more during high dialysate bicarbonate compared to low dialysate bicarbonate with mean between treatment differences: Stroke volume: 12 (1; 23) mL; Total peripheral resistance: -2.9 (-5.3; -0.5) mmHg/(L/min). Cardiac output tended to decrease more with high dialysate bicarbonate compared to low dialysate bicarbonate with mean between treatment difference 0.7 (0.0; 1.4) L/min. High dialysate bicarbonate caused alkalosis, hypocalcemia, and lower plasma potassium, whereas patients remained normocalcemic with normal pH during low dialysate bicarbonate. Orthostatic blood pressure response after dialysis did not differ significantly. The use of high dialysate bicarbonate compared to low dialysate bicarbonate was associated with hypocalcemia, alkalosis, and a more pronounced hypokalemia. During hemodialysis with UF, a better preservation of blood pressure, stroke volume, and cardiac output may be achieved with low dialysate bicarbonate compared to high dialysate bicarbonate.

Assessment of Physico-chemical Properties of Soil from Various Regions of Different Taluk of Pathanamthitta District in the State of Kerala, India

The assessment of Physico-Chemical Properties of Soil from Various Regions of Different Taluk of Pathanamthitta District of Kerala in 2023-24 was a valuable endeavour. A total of 27 samples were collected at profile depths of 0-15, 15-30, and 30-45. It is interesting to note the variations in soil colour between dry and wet conditions, ranging from light brown to dark reddish brown.The soil textural class was identified as Sandy clay Loam, and the sand, silt and clay percentage varied from 45.18% to 50.64%, 17.21% to 20.70%, 30.91% to 34.61%. Bulk Density was varied from 1.08 Mg m-3 to 1.28 Mg m-3. The Particle Density varied from 2.02 Mg m-3 to 2.55 Mg m-3. The Pore Space (%) ranged from 40.18% to 50.62%. The Water Retaining Capacity (%) ranged from 39.19 to 48.98%. The pH value ranged from 4.9 to 6.9. The Electrical Conductivity ranged from 0.03 to 0.30 dS m-1. The value of total Organic Carbon (%) varied from 0.16 to 1.68 %. The available Nitrogen content of soil ranged from 119.45 to 286.07 kg ha-1. The available Phosphorus content of soil ranged from 13.23 to 64.20 kg ha-1. Available Potassium content of soil ranged from 100.80 to 382.40 kg ha-1. Exchangeable Calcium content of soil ranged from 1.7(meq 100g-1) to 9.1(meq 100g-1). Exchangeable Magnesium content of soil ranged from 0.23 (meq 100g-1) to 0.74(meq 100g-1). The Sulphur content of soil ranged from 0.03 to 0.44 kg ha-1. The findings revealed minor increases in bulk and particle density with depth, yet the overall physical condition of the soil seems favourable for plant growth. It is evident that the soils are slightly acidic but meet the acceptable EC limit. The high levels of Organic Carbon are promising, while Nitrogen is lower and Phosphorus and Potassium levels are moderate to high. However, secondary nutrients like Calcium, Magnesium, and Sulphur are relatively low. Nutrient levels appear to be influenced by soil depth, with leaching due to higher precipitation levels in the area contributing to nutrient deficiencies. The results suggest that improvements can be made by implementing strategies such as cover crops, green manure, legume cultivation, mulching, and specific cropping systems to address leaching concerns.

Effect of ethanolamine as a steel corrosion inhibitor in realkalization of carbonated concrete

ABSTRACT This paper assessed the electromigration behavior of ethanolamine and its efficiency as a corrosion inhibitor of rebar during the realkalization. Cylindrical concrete specimen (diameter 45 mm, height 20 mm) with steel rebar (6 mm in diameter, 35 mm in length) were artificially carbonated and corroded in an accelerated manner with impressed anodic current. The specimens were realkalized in the electrolyte solution containing ethanolamine, while the steel rebars were connected to the cathodic current (200 mA·h, 1 A/m2). After 25 days of monitoring the repair process, experimental data revealed notable changes in electrochemical parameters. The corrosion potential increased from −627 mV to −236 mV, signifying a reduction in corrosion activity. The cathodic exchange current density decreased from 4.9 μA/cm2 to 2.3 μA/cm2, showing a decrease in the corrosion rate. Also, the pH value of the solution dropped to a comparatively lower level, the ethanolamine and potassium ion concentrations decreased from 22 to 30.54 g/L to 3.22 and 10.23 g/L, respectively. Moreover, nitrogen detection on the steel surface and varied levels of ethanolamine concentration at different depths in the concrete were also measured, both indicating a clear migration of inhibitor to the steel surface to form a passive film.

#1642 Influence of potassium intake on the renoprotective response to sodium restriction and hydrochlorothiazide in patients with diabetic nephropathy

Abstract Background and Aims Both salt restriction and hydrochlorothiazide (HCT) potentiate the antihypertensive and antiproteinuric effects of renin-angiotensin-aldosterone-system inhibitors (RAASi) in chronic kidney disease (CKD). Potassium intake is another dietary component that influences blood pressure (BP) and albuminuria. The influence of potassium intake on the response to sodium restriction during RAASi treatment in diabetic nephropathy is unknown. Method We performed a post-hoc analysis of a randomised, double blind, placebo-controlled cross-over trial (n = 43) investigating the combined and separate effects of low sodium (LS; aim 50 mmol Na+/d) and HCT (50 mg/d) on BP and albuminuria during background ACE inhibition (ACEi; lisinopril 40 mg/d) in patients with diabetic nephropathy. Each treatment (normal sodium (NS), LS, NS+HCT, LS+HCT) period consisted of six weeks. Participants were categorised as above or below median 24-hour urinary potassium excretion (UKV) at baseline, stratified by sex. Effects on BP and albuminuria were defined as % reduction from baseline systolic BP (SBP) and urinary albumin-creatinine ratio (ACR). Changes over time within both UKV subgroups were compared to baseline using repeated measures ANOVA (SBP) or paired Wilcoxon rank sum analysis (log-transformed ACR). Post-hoc between-group comparison was performed using Bonferroni testing. Results 43 patients (6 female; mean age 64.9±1.4 yrs) had UKV data available and were included in analysis. 33 patients had complete ACR data. Mean estimated glomerular filtration rate (eGFR) was 65.2 (±3.9), mean SBP was 146.6±2.4 mmHg and median albuminuria 648.6 [251.2 - 1883.0] mg/24 h. Median UKV in the high and low potassium groups was 64 [IQR 49-71] and 94 [90 – 111] mmol/24 u, respectively (p&amp;lt;0.0001). Mean baseline sodium excretion was higher in the high potassium group (191 vs. 260 mmol/d; P = .002), but percentual reduction in sodium excretion at SR was comparable between the two groups. There were no significant differences in baseline SBP, ACR, age and estimated glomerular filtration rate between the groups. LS led to a significant reduction of ACR in the high potassium group (P = .011), whereas in the low potassium group the ACR reduction was not significant (P = .058; Fig. 1). Similarly, addition of HCT to background ACEi therapy without salt restriction reduced ACR compared to ACEi monotherapy in the high potassium group (P &amp;lt; .0001), not the low potassium group (P = .211). LS+HCT combined led to a reduction in ACR in both high (P &amp;lt; .0001) and low potassium (P = .034) groups. A post-hoc between-group analysis showed a significantly larger ACR reduction for the high potassium group (P = .01) upon HCT therapy, and a trend towards larger reduction for HCT+LS (P = .05). The effect of LS alone was similar between high and low potassium groups (P = .485). During LS, within-group analysis showed a significant reduction in SBP compared to baseline for the low potassium group (P = .003), but not for the high potassium group (P = .208). In all further conditions, SBP was significantly reduced from baseline in both groups. Post-hoc analysis showed no significant differences in SBP reduction between high and low potassium groups, although there was a trend towards larger SBP reduction in the low potassium group during LS (P = .07). Conclusion Higher baseline potassium excretion is associated with stronger albuminuria lowering effects of salt restriction and HCT in patients with diabetic nephropathy on background ACEi therapy. These effects were not driven by similar effects on BP.

#2424 Higher 24-hour urine sodium-to-potassium ratio is associated with worse renal outome

Abstract Background and Aims Low sodium and high potassium intake are advised to control blood pressure and may improve long term cardiorenal outcomes. The optimal potassium intake for patients with chronic kidney disease remains to be defined. We investigated whether the 24-hour urine sodium-to-potassium ratio (Na/K-ratio), which incorporates estimates of both sodium and potassium intake, could predict long-term renal outcome. Method We selected adult outpatients of a Dutch tertiary hospital who collected at least one 24-hour urine collection with available sodium and potassium measurements between 1998-2023. Patients with a history of dialysis or kidney transplantation were excluded. We examined the need for persistent renal replacement therapy (RRT), defined as dialysis or kidney transplantation, using Cox regression. The association between the 24-hour urine Na/K-ratio and the estimated glomerular filtration rate (eGFR) slope was assessed using linear regression in patients who had ≥3 eGFR measurements available in ≥3 years. The linear regression analysis was adjusted for age, sex, baseline eGFR, diabetes mellitus and hypertension. In the Cox regression analysis, we additionally adjusted for the interaction between the 24-hour urine Na/K-ratio and baseline eGFR. Hypertension was defined as a clinical diagnosis or an office blood pressure ≥140/90 mmHg. Results We included 720 patients aged 50 ± 15 years, of whom 52% were male, 58% had hypertension and 31% diabetes mellitus. The baseline eGFR was 64 ± 34 ml/min/1.73 m2. The 24-hour urine Na/K ratio was 2.5 ± 1.2 in a median number of 1 (IQR = 1-2) urine collection. During a median follow-up of 11.2 (14.0) years, 29% of patients needed RRT. In 575 patients with sufficient eGFR measurements (mean 12 ± 8 measurements per subject) the median annual eGFR decline was 1.51 (IQR = 0.49-3.98) ml/min/1.73 m2. Every unit increase in the 24-hour urine Na/K-ratio was associated with a 19% higher risk for persistent RRT need (HR 1.19, 95% CI 1.03-1.39; p = 0.02) and an additional 0.44 ml/min/1.73 m2 (95% CI −0.83, −0.04; p = 0.03) decline in eGFR. Conclusion This study suggests that higher 24-hour urine Na/K-ratio is associated with faster kidney function decline and the need for RRT, independent of hypertension, in a selected group of outpatients.

#1328 Haemodynamic effects of low versus high dialysate bicarbonate concentration in haemodialysis patients

Abstract Background and Aims Haemodialysis (HD) treatment using standard dialysate bicarbonate concentrations cause transient metabolic alkalosis possibly associated with haemodynamic instability. We performed a detailed comparison of blood pressure (BP), haemodynamic parameters, electrolytes and orthostatic BP response with low (LDB) versus high dialysate bicarbonate concentration (HDB). Method Fifteen HD patients were examined in a single-blind, randomised, controlled, crossover study. Participants underwent a 4-hour HD session with dialysate bicarbonate concentration of 30 mmol/l (LDB) or 38 mmol/l (HDB) with one week between interventions. During HD, cardiac output (CO), total peripheral resistance (TPR), stroke volume (SV) and central blood volume were measured with ultrasound dilution technique (Transonic). Throughout dialysis, blood samples were obtained from the arterial cannula. Orthostatic BP was measured pre and post HD. Results With similar ultrafiltration volume (2.6 litres), systolic BP tended to decrease more during HDB compared to LDB (Fig. 1 and Table 1); the mean (95% confidence interval) between treatment differences in systolic BP were: 8 (-4;20) mmHg (end of HD) and 7 (0;15) mmHg (post HD). SV decreased (Fig. 2) whereas TPR increased significantly more during HDB compared to LDB with mean between treatment differences: SV: 12 (1;23) ml; TPR: -2.9 (-5.3;-0.5) mmHg/(L/min). CO tended to decrease more with HDB compared to LDB with mean between treatment difference 0.7 (0.0;1.4) L/min. HDB caused alkalosis, hypocalcaemia and lower plasma potassium, whereas patients remained normocalcaemic with normal pH during LDB (Table 1). Orthostatic BP response after dialysis did not differ significantly. Conclusion HDB compared to LDB was associated with hypocalcaemia and alkalosis and a more pronounced hypokalaemia which may impair preservation of BP, SV and CO during HD.