Assessing the performance of a robust multiparametric wearable patch integrating silicon-based sensors for real-time continuous monitoring of sweat biomarkers.

The development of wearable devices for sweat analysis has experienced significant growth in the last two decades, being the main focus the monitoring of athletes health during workouts. One of the main challenges of these approaches has been to attain the continuous monitoring of sweat for time periods over 1 h. This is the main challenge addressed in this work by designing an analytical platform that combines the high performance of potentiometric sensors and a fluidic structure made of a plastic fabric into a multiplexed wearable device. The platform comprises Ion-Sensitive Field-Effect Transistors (ISFETs) manufactured on silicon, a tailor-made solid-state reference electrode, and a temperature sensor integrated into a patch-like polymeric substrate, together with the component that easily collects and drives samples under continuous capillary flow to the sensor areas. ISFET sensors for measuring pH, sodium, and potassium ions were fully characterized in artificial sweat solutions, providing reproducible and stable responses. Then, the real-time and continuous monitoring of the biomarkers in sweat with the wearable platform was assessed by comparing the ISFETs responses recorded during an 85-min continuous exercise session with the concentration values measured using commercial Ion-Selective Electrodes (ISEs) in samples collected at certain times during the session. The developed sensing platform enables the continuous monitoring of biomarkers and facilitates the study of the effects of various real working conditions, such as cycling power and skin temperature, on the target biomarker concentration levels.

Sodium content in plant and insect food resources consumed by chimpanzees (Pan troglodytes schweinfurthii) in Gombe National Park, Tanzania.

OBJECTIVES: Many nonhuman primate diets are dominated by plant foods, yet plant tissues are often poor sources of sodium-a necessary mineral for metabolism and health. Among primates, chimpanzees (Pan troglodytes), which are ripe fruit specialists, consume diverse animal, and plant resources. Insects have been proposed as a source of dietary sodium for chimpanzees, yet published data on sodium values for specific foods are limited. We assayed plants and insects commonly eaten by chimpanzees to assess their relative value as sodium sources. MATERIALS AND METHODS: We used atomic absorption spectroscopy to determine sodium content of key plant foods and insects consumed by chimpanzees of Gombe National Park, Tanzania. Dietary contributions of plant and insect foods were calculated using feeding observational data. RESULTS: On a dry matter basis, mean sodium value of plant foods (n = 83 samples; mean = 86 ppm, SD = 92 ppm) was significantly lower than insects (n = 12; mean = 1549 ppm, SD = 807 ppm) (Wilcoxon rank sum test: W = 975, p < 0.001). All plant values were below the suggested sodium requirement (2000 ppm) for captive primates. While values of assayed insects were variable, sodium content of two commonly consumed insect prey for Gombe chimpanzees (Macrotermes soldiers and Dorylus ants) were four to five times greater than the highest plant values and likely meet requirements. DISCUSSION: We conclude that plant foods available to Gombe chimpanzees are generally poor sources of sodium while insects are important, perhaps critical, sources of sodium for this population.

High-resolution community-level sodium variation on the Tibetan Plateau: Content, density, and storage.

Sodium (Na), a beneficial mineral element, stimulates plant growth through osmotic adjustment. Previous studies focused on Na content at the individual or species level, however, it is hard to link to ecosystem functions without exploring the characteristics (content, density, and storage) of Na at the community level. We conducted grid-plot sampling of different plant organs in 2040 natural plant communities on the Tibetan Plateau (TP) to comprehensively characterize community-level Na on a regional scale. The Na content was 0.57, 0.09, 0.07, and 0.71 mg g-1 in leaves, branches, trunks, and roots, respectively. Across biomes Na content was higher in deserts under drought stress. Oxygen partial pressure, radiation, precipitation, soil Na supply, and temperature significantly affected the spatial variation in Na content. Furthermore, we accurately simulated the spatial variation in Na density and produced a highly precise 1 km × 1 km spatial map of plant Na density on the TP using random forest algorithm, which demonstrated higher Na density in the southeast of TP. The total plant Na storage on the TP was estimated as 111.80 × 104 t. These findings provide great insights and references for understanding the plant community-level adaptation strategies and evaluating the mineral element status on a large scale, and provide valuable data for ecological model optimization in the future.

Effect of milking time on yield, composition, and antimicrobial components of milk in lactating goats.

Various studies have attempted to improve the milk yield and composition in dairy animals. However, no study has examined the effects of milking at different times on milk yield and composition. Therefore, this study aimed to compare the yield, composition, and antimicrobial components of milk obtained from milking at different times in lactating goats. Eight goats were milked once daily at different times for three consecutive weeks (first week: 06:00 h; second week: 09:00 h; and third week: 12:00 h). The light ranged from 06:30 to 19:00 h. Milk and blood samples were collected once a day during milking time. Milking at 09:00 h resulted in a significantly higher milk yield than that obtained after milking at 06:00 and 12:00 h. Prolactin levels in plasma and the fat, Na+, ß-defensin, and S100A7 (antimicrobial component) levels in milk were the lowest in the 09:00 h milking. These results indicate that milk yield, composition, and antimicrobial components can be affected by milking time, which may be related to the altered concentration of prolactin in the blood. These findings provide a rational basis for achieving maximal milk production with strong immunity by changing to a more effective milking time.

Sodium removal per ultrafiltration volume in automated peritoneal dialysis in pediatric patients.

BACKGROUND: The standard rate of sodium removal in adult anuric patients on continuous ambulatory peritoneal dialysis (CAPD) is 7.5 g/L of ultrafiltration volume (UFV). Although automated PD (APD) is widely used in pediatric patients, no attempt has yet been made to estimate sodium removal in APD. METHODS: The present, retrospective cohort study included pediatric patients with APD who were managed at Tokyo Metropolitan Children's Medical Center between July 2010 and November 2017. The patients underwent a peritoneal equilibrium test (PET) at our hospital. Sodium removal per UFV was calculated by peritoneal function and dwell time using samples from patients on APD with 1- and 2-h dwell effluent within three months of PET and 4- and 10-h dwell effluent at PET. RESULTS: In total, 217 samples from 18 patients were included, with 63, 81, and 73 of the samples corresponding to the High [H], High-average [HA], and Low-average [LA] PET category, respectively. Sodium removal per UFV (g/L in salt equivalent) for dwell times of one, two, four, and ten hours was 5.2, 8.8, 8.0, and 11.5 for PET [H], 5.3, 5.8, 5.6, and 8.1 for PET [HA], and 4.6, 5.1, 5.1, and 7.1 for PET [LA], respectively. CONCLUSIONS: Sodium removal per UFV in pediatric APD was less than the standard adult CAPD and tended to be lower with shorter dwell times, leading to sodium accumulation. Therefore, salt intake should be restricted in combination with one or more long daytime dwells, especially in anuric patients.

Decrease in electrolyte after vitrectomy surgery may affect the results of forensic investigations using vitreous humor.

PURPOSE: Vitreous humor (VH) is used for postmortem biochemical studies because it is well protected in an uncontaminated state even after death. The goal of this research was to investigate electrolyte concentrations in the VH from human eyes with and without a history of vitrectomy surgery. METHODS: We analyzed the sodium (Na), potassium (K), chloride (Cl) and magnesium (Mg) concentrations from 34 VH samples from 34 patients. Eleven samples were from eyes with a history of vitrectomy, and the remaining 23 eyes had no history of vitrectomy. The correlations of Na, K, Cl and Mg concentrations with patient age, interval between first and second vitrectomy, and lens status (history of cataract surgery) were also evaluated. RESULTS: The Na, K, Cl and Mg concentrations in VH from vitrectomized eyes were 134.1 ± 7.9 mmol/L, 3.7 ± 0.2 mmol/L, 99.7 ± 6.7 mmol/L and 0.59 ± 0.09 mmol/L, respectively; all were significantly lower than the corresponding concentrations in VH from control eyes (lower by 5.0%, 11.0%, 11.7%, and 22.6%, respectively). Na, K, Cl and Mg concentrations in VH from vitrectomized eyes did not show significant correlations with patient ages or the interval between their first and second vitrectomies. There were no significant differences in Na, K, Cl and Mg concentrations in VH between phakic eyes and intraocular lens-implanted eyes. CONCLUSIONS: With the increasing number of vitrectomies being performed, it is necessary to consider the history of vitrectomy when using a subject's VH in forensic examination.

Quality and Flavor Difference in Dry-Cured Meat Treated with Low-Sodium Salts: An Emphasis on Magnesium.

The present study aimed to develop low-sodium curing agents for dry-cured meat products. Four low-sodium formulations (SPMA, SPM, SP, and SM) were used for dry-curing meat. The physicochemical properties and flavor of the dry-cured meat were investigated. The presence of Mg2+ ions hindered the penetration of Na+ into the meat. The weight loss, moisture content, and pH of all low-sodium salt groups were lower than those of S. Mg2+ addition increased the water activity (Aw) of SPMA, SPM, and SM. Dry-curing meat with low-sodium salts promoted the production of volatile flavor compounds, with Mg2+ playing a more prominent role. Furthermore, low-sodium salts also promoted protein degradation and increased the content of free amino acids in dry-cured meat, especially in SM. Principal component analysis (PCA) showed that the low-sodium salts containing Mg2+ were conducive to improving the quality of dry-cured meat products. Therefore, low-sodium salts enriched with Mg2+ become a desirable low-sodium curing agent for achieving salt reduction in dry-cured meat products.

Effect of low milking frequency on the concentration of antimicrobial proteins in goat milk.

This study examined the effects of low frequency milking on the concentrations of antimicrobial components in goat milk. Sixteen goats were divided into two groups of eight each: milking once every 2 d three times (for six days, three times group) or five times (for 10 days, five times group). On other days, milking was performed once daily. Milk was collected, and milk yield, somatic cell count (SCC), and the concentrations of some antimicrobial proteins such as lactoferrin (LF), S100A7, IgA, and sodium ions (Na+) in milk were measured. Milk yield significantly decreased in both the groups during the low-milking frequency period, followed by an increase above the low frequency milking period in both groups. In contrast, SCC and LF concentrations in milk increased in both groups during the low frequency milking period. The concentration of S100A7 in milk temporarily decreased after the low frequency milking period, followed by a significant increase. The S100A7 concentration during this period was higher in the five times group than in the three times group. These results indicated that low frequency milking induced a gradual decrease in milk yield and a concomitant increase in antimicrobial components, such as LF and S100A7, in milk. This increase in the antimicrobial components may be useful in preventing mastitis.

Wireless wearable potentiometric sensor for simultaneous determination of pH, sodium and potassium in human sweat.

This paper reports on the development of a flexible-wearable potentiometric sensor for real-time monitoring of sodium ion (Na+), potassium ion (K+), and pH in human sweat. Na0.44MnO2, polyaniline, and K2Co[Fe(CN)6] were used as sensing materials for Na+, H+ and K+ monitoring, respectively. The simultaneous potentiometric Na+, K+, and pH sensing were carried out by the developed sensor, which enables signal collection and transmission in real-time to the smartphone via a Wi-Fi access point. Then, the potentiometric responses were evaluated by a designed android application. Na+, K+, and pH sensors illustrated high sensitivity (59.7 ± 0.8 mV/decade for Na+, 57.8 ± 0.9 mV/decade for K+, and 54.7 ± 0.6 mV/pH for pH), excellent stability, and good batch-to-batch reproducibility. The results of on-body experiments demonstrated that the proposed platform is capable of real-time monitoring of the investigated ions.

Temporal dynamics of drinking water sodium levels in coastal areas, Cyprus 2009-2020.

Around the world, groundwater salinity levels are increasing in coastal areas, as a result of its systematic overexploitation for domestic, agricultural and industrial demand and potentially due to climate change manifestations (such as, sea level rise). We hypothesized that the groundwater quality of many Mediterranean coastal areas is already being perturbed, especially for water salinity, depending on the groundwater distance from the seafront. The objectives of this study were: i) to evaluate the magnitude and temporal variance of drinking water sodium (Na) as a metric of salt intake used for public health purposes using drinking water data in Cyprus; and ii) to examine the degree of Na enrichment in drinking water as defined by the seawater coastline distance of each sampling point. Open access governmental data of drinking water Na (n = 3304), daily max ambient air temperature and total rainfall were obtained for the period of 2009-2020 from governmental repositories. Linear mixed-effect regression models of drinking water Na with unsupervised covariance matrix were used. After adjusting for temperature and rainfall data, there was a significant annual increase in drinking water Na levels over time (beta = 0.01; 95 % CI: 0.00, 0.02; p = 0.02) for the coastal areas (<10 km from coastline, cutoff used by the EU Environment Agency), but this was not the case for non-coastal areas (>10 km distance from coastline). The distance of each sampling point from the coastline in Cyprus was negatively associated with drinking water Na in coastal areas (beta = -0.04, 95%CI: -0.06, -0.01; p = 0.002); this was not the case for non-coastal areas. More research is warranted to better understand the impacts of global environmental change on water quality in association with the burden of disease in coastal areas.

Spatiotemporal variations, health risk assessment, and sources of potentially toxic elements in potamic water of the Anday Stream Basin (Türkiye), Black Sea Region.

Monitoring and protecting freshwater habitats are paramount for a sustainable water management perspective. This study investigated potentially toxic elements (PTEs) in the potamic water of the Anday Stream Basin (Türkiye), Black Sea Region, for a hydrological year (from May 2020 to April 2021). Among PTEs, the highest average values were recorded for sodium (Na) at 41.3 mg/L and the lowest for mercury (Hg) at 0.009 µg/L and noted under quality guidelines. The stream was found to be at the level of "Low Heavy Metal Pollution" and "Low Contamination" based on the ecotoxicological risk indices. The highest calculated hazard quotient (HQ) value of 1.21E-02 for Cd was noted in the children via the dermal pathway and the lowest of 6.91E-06 for Fe in adults via the ingestion pathway. Results revealed a higher hazard index (HI) value of 1.50E-02 for Cd to children and the lowest of 1.98E-05 for Fe to adults. As a result of applying agricultural risk indices, the stream showed sodium adsorption ratio values less than 6 and was found to be "Excellent" for agriculture. However, the sodium percentage values were less than 20 and found "Permissible" and the magnesium hazard > 50 and noted as "Unsuitable" for agriculture. Statistical analysis revealed that natural factors mainly attributed to PTE contamination of the Anday Stream Basin.

Assessment of coastal river water quality in Bangladesh: Implications for drinking and irrigation purposes.

Saltwater intrusion in the coastal areas of Bangladesh is a prevalent phenomenon. However, it is not conducive to activities such as irrigation, navigation, fish spawning and shelter, and industrial usage. The present study analyzed 45 water samples collected from 15 locations in coastal areas during three seasons: monsoon, pre-monsoon, and post-monsoon. The aim was to comprehend the seasonal variation in physicochemical parameters, including water temperature, pH, electrical conductivity (EC), salinity, total dissolved solids (TDS), hardness, and concentrations of Na+, K+, Mg2+, Ca2+, Fe2+, HCO3-, PO43-, SO42-, and Cl-. Additionally, parameters essential for agriculture, such as soluble sodium percentage (SSP), sodium absorption ratio (SAR), magnesium absorption ratio (MAR), residual sodium carbonate (RSC), Kelly's ratio (KR), and permeability index (PI), were examined. Their respective values were found to be 63%, 16.83 mg/L, 34.92 mg/L, 145.44 mg/L, 1.28 mg/L, and 89.29%. The integrated water quality index was determined using entropy theory and principal component analysis (PCA). The resulting entropy water quality index (EWQI) and SAR of 49.56% and 63%, respectively, indicated that the samples are suitable for drinking but unsuitable for irrigation. These findings can assist policymakers in implementing the Bangladesh Deltaplan-2100, focusing on sustainable land management, fish cultivation, agricultural production, environmental preservation, water resource management, and environmental protection in the deltaic areas of Bangladesh. This research contributes to a deeper understanding of seasonal variations in the hydrochemistry and water quality of coastal rivers, aiding in the comprehension of salinity intrusion origins, mechanisms, and causes.

Evidence from experiments, modeling, and field observations for effects of increased salinization on re-distribution of sediment base cations in Taihu Lake, China.

Taihu Lake, the third largest freshwater lake in China, has experienced rapid salinization in the past decades; however, little is known about the impact of sodium (Na) on ion exchange in the lake environment. To explore the potential effect of increased Na on the migration of base cations (Ca and Mg) and resulting redistribution between the water and sediment, we used the adsorption-exchange experiment, MINTEQ modeling to explore the cation exchange induced by high Na input, and its impact on the redistribution of Ca and Mg in Taihu different media. The results indicated that exchanged quantity of Ca and Mg increased with time, and the exchange process reached 90% during 0-4 h and reached equilibrium after 24 h under 100 mg/L Na (the maximum Na concentration in Taihu sediment pore water). Our MINTEQ modeled result indicated that the exchanged quantity of Ca and Mg increased with the increasing Na concentration, with Ca being preferably exchanged over Mg at the same Na concentration. The MINTEQ model further predicted that, in the Taihu lake environment, the exchange adsorption would reach the equilibrium at the concentration of 6000 mg/L Na, with exchanged Ca2+ and Mg2+ accounting for 47% and 55% of the total exchangeable Ca and Mg in the sediment, respectively. Although current Na-induced exchange in the Taihu lake has been far from the equilibrium, the MINTEQ result confirmed the existence of this reaction and predicted the potential redistribution of base cations or Ca/Mg ratio in the lake sediment and water phase with further Na increase. Furthermore, our field observations not only confirmed the existence of Na-induced cation exchange in this lake environment but also were generally in agreement with our experimental and modeled results. The increased salinization-induced ion exchange would alter the re-distribution of base cations and the resulting potential ecosystem consequences should be given close attention in this large freshwater lake.

A wearable microfluidic system for efficient sweat collection and real-time detection.

Sweat is an important biofluid with rich physiological information that can evaluate human health condition. Wearable sweat sensors have received widespread attention in recent years due to the benefits of non-invasive, continuous, and real-time monitoring. Currently, an efficient device integrating sweat collection and detection is still needed. Here, a wearable sweat microfluidic system was fabricated for real-time collection and analysis of sweat. The fabricated microfluidic system consisted of four layers, including a skin adhesive layer, a microfluidic layer, an electrode layer, and a capping layer. The sweat collection rate was around 0.79 µL/min, which demonstrated efficient sweat sampling, storage, and refreshing capabilities. Simultaneous detection of multiple sweat biomarkers was achieved with a screen-printed sweat sensing array, which could realize high-precision detection of Na+, K+, and glucose. Moreover, the sensing array also showed good repeatability and stability, with a relative standard deviation of sensitivity of less than 5%. Additionally, human testing was conducted to demonstrate that this microfluidic system can continuously monitor Na+, K+, and glucose in subjects' sweat during exercise, which showed high potential for non-invasive human health monitoring.

Reliability and validity of the MX3 portable sweat sodium analyser during exercise in warm conditions.

PURPOSE: Accurately measuring sweat sodium concentration ([Na+]) in the field is advantageous for coaches, scientists, and dieticians looking to tailor hydration strategies. The MX3 hydration testing system is a new portable analyser that uses pre-calibrated biosensors to measure sweat [Na+]. This study aimed to assess the validity and reliability of the MX3 hydration testing system. METHODS: Thirty-one (11 females) recreationally active participants completed one experimental trial. During this trial, participants exercised at a self-selected pace for 45 min in a warm environment (31.5 ± 0.8 °C, 63.2 ± 1.3% relative humidity). Sweat samples were collected from three measurement sites using absorbent patches. The samples were then analysed for sweat [Na+] using both the MX3 hydration testing system and the Horiba LAQUAtwin-NA-11. The reliability of the MX3 hydration testing system was determined following two measurements of the same sweat sample. RESULTS: The mean difference between measurements was 0.1 mmoL·L-1 (95% limits of agreement (LoA): - 9.2, 9.4). The analyser demonstrated a coefficient of variation (CV) of 5.6% and the standard error of measurement was 3.3 mmoL·L-1. When compared to the Horiba LAQUAtwin-NA-11, there was a mean difference of - 1.7 mmoL·L-1 (95% LoA: - 0.25 X ¯ , 0.25 X ¯ ) and the CV was 9.8%. CONCLUSION: The MX3 hydration testing system demonstrated very good single-trial reliability, moderate agreement and a very good CV relative to the Horiba LAQUAtwin-Na-11. To further validate its performance, the MX3 hydration testing system should be compared with analytical techniques known for superior reliability and validity.

Interdialytic weight gain and low dialysate sodium concentration in patients on chronic hemodialysis: a systematic review and meta-analysis.

PURPOSE: The present systematic review and meta-analysis aimed at evaluating the effect of low dialysate sodium concentration on interdialytic weight gain (IDWG) in chronic hemodialysis patients. METHODS: Studies were eligible for inclusion if they were English language papers published in a peer-reviewed journal and met the following inclusion criteria: (1) studies in adult patients (over 18 years of age), (2) included patients on chronic hemodialysis since at least 6 months; (3) compared standard (138-140 mmol/l) or high (> 140 mmol/l) dialysate sodium concentration with low (< 138 mmol/l) dialysate sodium concentration; (4) Included one outcome of interest: interdialytic weight gain. Medline, PubMed, Web of Science, and the Cochrane Library were searched for the quality of reporting for each study was performed using the Quality Assessment Tool of Controlled Intervention Studies of the National Institutes of Health. The quality of reporting of each cross-over study was performed using the Revised Cochrane Risk of Bias (RoB) tool for cross-over trials as proposed by Ding et al. RESULTS: Nineteen studies (710 patients) were included in the analysis: 15 were cross-over and 4 parallel randomized controlled studies. In cross-over studies, pooled analysis revealed that dialysate sodium concentration reduced IDWG with a pooled MD of - 0.40 kg (95% CI - 0.50 to - 0.30; p < 0.001). The systematic review of four parallel, randomized, studies revealed that the use of a low dialysate sodium concentration was associated with a significant reduction of the IDWG in two studies, sustained and almost significant (p = 0.05) reduction in one study, and not significant reduction in one study. CONCLUSION: Low dialysate sodium concentration reduces the IDWG in prevalent patients on chronic hemodialysis.

Trace metals and nutrient analysis of marine fish species from the Gwadar coast.

Trace metals are naturally occurring metals found in very small concentrations in the environment. In the context of fish flesh, metals such as copper, calcium, potassium, sodium, zinc, iron, and manganese are absorbed by fish and play vital roles in various physiological functions. However, if these metals exceed the recommended limits set by WHO/FAO, they are termed 'toxic metals' due to their harmful impacts on both the fish and its consumers. Therefore, the present study aims to analyze the levels of protein, lipids, and certain metals-Aluminum (Al), Sodium (Na), Zinc (Zn), Titanium (Ti), Iron (Fe), Copper (Cu), Potassium (K), and Calcium (Ca) in three commercially important marine fishes i.e. Rastrelliger kanagurta, Sardinella abella, and Otolithes ruber. The study also aims to assess their potential impact on human health. The macro-Kjeldhal method and Soxhlet apparatus were used to estimate protein and lipid contents, while atomic absorption spectroscopy (AAS) was used to estimate trace metals found in fishes. The study found that these fish species are valuable sources of protein, lipids, and certain essential minerals. The protein content (CP) in these three species ranged from 63.35 to 86.57%, while lipid content was from 21.05 to 23.86%. The overall results of the trace metal concentrations analyzed in the present study revealed that Aluminum (Al), Sodium (Na), Zinc (Zn), Titanium (Ti), Copper (Cu), Potassium (K), and Calcium (Ca) were found in low concentration or traces and also within suitable ranges as set by WHO/FAO. However, Iron (Fe) was absent in all three species. Moreover, both copper and potassium were found in all three species, while Zinc was present in Rastrelliger kanagurta and Sardinella abella, calcium in Sardinella abella, and sodium in Otolithes ruber only. Titanium was recorded for the first time in S. abella. However, the total health risk assessment associated with these fish food consumption was measured by THQ and TTHQ and found to be less than 1, which shows no potential risk related to trace metals found in these fishes on human health upon their consumption. In conclusion, these commercially important marine fish species were found valuable sources of protein, lipids, and essential trace minerals that are necessary for human health. Thus, the current study provides useful information for the local population to make informed decisions about their daily diets and highlights the importance of sustainable fishing practices to maintain these valuable marine resources by periodical monitoring of their ecosystem.

"Milk on Ice": A detailed analysis of Ernest Shackleton's century-old whole milk powder in comparison with modern counterparts.

Whole milk powder (WMP) manufactured in New Zealand in 1907 was sent to the Antarctic continent with the Shackleton-led British Antarctic Expedition from 1907 to 1909. This powder was stored at ambient conditions at Shackleton's Hut at Cape Royds, Antarctica, for over 100 yr before a sample was collected on behalf of Fonterra by the Antarctic Heritage Trust. Having spent most of its existence both dried and in frozen storage, any deleterious reactions within the WMP would have been markedly retarded. The composition and some properties of the roller-dried Shackleton's WMP are reported along with those of 2 modern spray-dried New Zealand WMP. The Shackleton powder was less white and more yellow than the modern WMP and was composed of flakes rather than agglomerated particles, consistent with that expected of a roller-dried powder. Headspace analysis showed lipolytic and oxidative volatile compounds were present in the Shackleton WMP, indicting some deterioration of the milk either before powder manufacture or on storage of the finished product. On a moisture-free basis, the Shackleton WMP had higher protein, higher fat (with a markedly higher free fat level), higher ash, and a lower lactose level than the modern WMP. The lysine level was lower in the Shackleton WMP compared with the spray-dried powders, whereas the fatty acid composition was relatively similar. The sodium level was markedly higher in the Shackleton WMP compared with the spray-dried powder, which is probably due to the addition of an alkaline sodium salt to adjust the pH of the milk before roller drying. Lead, iron, and tin levels were markedly higher in the Shackleton WMP compared with the spray-dried powders, possibly due to the equipment used in powder manufacture and the tin-plated cases used for storage. The proteins in the Shackleton WMP were more lactosylated than in the spray-dried powders. The Shackleton WMP had a higher ratio of κ-casein A to B variants and a higher ratio of ß-lactoglobulin B to A variants than the spray-dried powders, whereas the αS1-casein, ß-casein, αS2-casein, and α-lactalbumin protein variants were similar in all powders. The total phospholipid content was markedly lower in the Shackleton WMP than the spray-dried powders, primarily due to a lower phosphatidylethanolamine concentration. The molecular species distributions within the phospholipid classes were generally similar in the 3 powders. Claims are sometimes encountered that the milk of today is different from that consumed by previous generations. However, this comparative study has shown that the Shackleton WMP was generally similar to modern WMP. Although differences in some components and properties were observed, these were attributable to the manufacturing equipment and processes used in the pioneering years of WMP manufacture.

Predicting solute transfer rate in patients initiating peritoneal dialysis.

BACKGROUND: While assessment of membrane characteristics is fundamental to peritoneal dialysis (PD) prescription in patients initiating therapy, peritoneal equilibration test has theoretical and practical drawbacks. We wished to determine whether an equation using simple clinical variables could predict fast (above population mean) peritoneal solute transfer rate without dialysate sampling. METHODS: We measured peritoneal solute transfer rate, as determined by peritoneal equilibration test using the 4-h dialysate to plasma creatinine ratio, in consecutive PD outpatients attending a single tertiary hospital for their first clinical follow-up within 3 months of dialysis initiation. An equation estimating peritoneal solute transfer rate based on readily available clinical variables was generated in a randomly selected modeling group and tested in a distinct validation group. RESULTS: We included 712 patients, with 562 in the modeling group and 150 in the validation group. Mean age was 58.4 ± 15.9 with 431 (60.5%) men. Mean peritoneal solute transfer rate value was 0.73 ± 0.13. An equation based on gender, race, serum sodium and albumin yielded a receiving operator characteristics (ROC) area under the curve (AUC) to detect fast peritoneal solute transfer rate (> 0.73) of 0.74 (0.67-0.82). Estimated peritoneal solute transfer rate values based on percentiles 15th (> 0.66), 20th (> 0.68), 25th (> 0.69) and 30th (> 0.70) could rule out fast peritoneal solute transfer rate with negative predictive values of 100%, 93.5%, 84.2% and 80.0%, respectively. CONCLUSIONS: An equation based on simple clinical variables allows ruling out fast transport in a significant proportion of patients initiating PD with a high degree of confidence without requiring dialysate sampling. This could prove useful in guiding dialysis prescription of PD patients in daily clinical practice, particularly in low-resource settings.

Do Not Turn a Blind Eye on Forensic Biochemistry: Using Vitreous Electrolytes to Reveal Renal Insufficiency as Cause of Death.

ABSTRACT: In both medical and forensic autopsy, the kidneys may be overlooked grossly and histologically. As both acute and chronic kidney dysfunction have major implications on morbidity and mortality, it is essential to consider the kidneys as a pathologic source for both immediate and proximate cause of death. For decades, vitreous humor has been used as a measure of postmortem electrolyte analysis to help understand ionic disturbances carried over from the antemortem period. Renal insufficiency from both acute and chronic kidney dysfunction can be ascertained from vitreous investigations and should be a consideration for cause of death. Here, we present 4 cases in which vitreous analysis was used to determine the cause of death. In highlighting these cases, we support the use of biochemical testing in autopsy while demonstrating how it can help elucidate an often overlooked means of mortality. Importantly, it can help with the formulation of clinicopathologic correlations between antemortem and postmortem findings.