Association of hydration status and in-hospital mortality in critically ill patients with ischemic stroke: Data from the MIMIC-IV database.

BACKGROUND: Hydration plays a critical role in the pathophysiological progression of ischemic stroke. However, the impact of extreme hydration on the mortality of critically ill patients with ischemic stroke remains unclear. Therefore, our objective was to evaluate the association between hydration, as indicated by the blood urea nitrogen to creatinine ratio (UCR), and in-hospital mortality in critically ill patients with ischemic stroke. METHODS: Data from the Medical Information Mart for Intensive Care (MIMIC-IV) database were utilized. Patients with ischemic stroke admitted to the Intensive Care Unit (ICU) for the first time were identified. The exposure variable was the hydration state represented by the UCR. The study outcome measure was in-hospital mortality. The primary analytical approach involved multivariate Cox regression analysis. Kaplan-Meier curves were constructed, and subgroup analyses with interaction were performed. RESULTS: A total of 1539 patients, with a mean age of 69.9 years, were included in the study. Kaplan-Meier curves illustrated that patients in higher UCR tertiles exhibited increased in-hospital mortality. Accordingly, the risk of in-hospital mortality significantly rose by 29 % with every 10 units increase in UCR. Subgroup analysis indicated a robust association between UCR and in-hospital mortality in each subgroup, with no statistically significant interactions observed. CONCLUSION: Hydration status is significantly associated with in-hospital all-cause mortality in critically ill patients with ischemic stroke. This finding underscores the importance of closely monitoring critically ill patients for adequate hydration and implementing appropriate rehydration strategies.

Physiological, transcriptomic and metabolomic insights of three extremophyte woody species living in the multi-stress environment of the Atacama Desert.

MAIN CONCLUSIONS: In contrast to Neltuma species, S. tamarugo exhibited higher stress tolerance, maintaining photosynthetic performance through enhanced gene expression and metabolites. Differentially accumulated metabolites include chlorophyll and carotenoids and accumulation of non-nitrogen osmoprotectants. Plant species have developed different adaptive strategies to live under extreme environmental conditions. Hypothetically, extremophyte species present a unique configuration of physiological functions that prioritize stress-tolerance mechanisms while carefully managing resource allocation for photosynthesis. This could be particularly challenging under a multi-stress environment, where the synthesis of multiple and sequential molecular mechanisms is induced. We explored this hypothesis in three phylogenetically related woody species co-occurring in the Atacama Desert, Strombocarpa tamarugo, Neltuma alba, and Neltuma chilensis, by analyzing their leaf dehydration and freezing tolerance and by characterizing their photosynthetic performance under natural growth conditions. Besides, the transcriptomic profiling, biochemical analyses of leaf pigments, and metabolite analysis by untargeted metabolomics were conducted to study gene expression and metabolomic landscape within this challenging multi-stress environment. S. tamarugo showed a higher photosynthetic capacity and leaf stress tolerance than the other species. In this species, a multifactorial response was observed, which involves high photochemical activity associated with a higher content of chlorophylls and ß-carotene. The oxidative damage of the photosynthetic apparatus is probably attenuated by the synthesis of complex antioxidant molecules in the three species, but S. tamarugo showed the highest antioxidant capacity. Comparative transcriptomic and metabolomic analyses among the species showed the differential expression of genes involved in the biosynthetic pathways of key stress-related metabolites. Moreover, the synthesis of non-nitrogen osmoprotectant molecules, such as ciceritol and mannitol in S. tamarugo, would allow the nitrogen allocation to support its high photosynthetic capacity without compromising leaf dehydration tolerance and freezing stress avoidance.

All-in-One, Wireless, Multi-Sensor Integrated Athlete Health Monitor for Real-Time Continuous Detection of Dehydration and Physiological Stress.

Athletes are at high risk of dehydration, fatigue, and cardiac disorders due to extreme performance in often harsh environments. Despite advancements in sports training protocols, there is an urgent need for a non-invasive system capable of comprehensive health monitoring. Although a few existing wearables measure athlete's performance, they are limited by a single function, rigidity, bulkiness, and required straps and adhesives. Here, an all-in-one, multi-sensor integrated wearable system utilizing a set of nanomembrane soft sensors and electronics, enabling wireless, real-time, continuous monitoring of saliva osmolality, skin temperature, and heart functions is introduced. This system, using a soft patch and a sensor-integrated mouthguard, provides comprehensive monitoring of an athlete's hydration and physiological stress levels. A validation study in detecting real-time physiological levels shows the device's performance in capturing moments (400-500 s) of synchronized acute elevation in dehydration (350%) and physiological strain (175%) during field training sessions. Demonstration with a few human subjects highlights the system's capability to detect early signs of health abnormality, thus improving the healthcare of sports athletes.

Model-Assisted Optimization of Xylose, Arabinose, Glucose, Mannose, Galactose and Real Hemicellulose Streams Dehydration To (Hydroxymethyl)Furfural and Levulinic Acid.

Conversion of hemicellulose streams and the constituent monosaccharides, xylose, arabinose, glucose, mannose, and galactose, was conducted to produce value-added chemicals, including furfural, hydroxymethylfurfural (HMF), levulinic acid and anhydrosugars. The study aimed at developing a kinetic model relevant for direct post-Organosolv hemicellulose conversion. Monosaccharides served as a tool to in detail describe the kinetic behavior and segregate contribution of hydrothermal decomposition and acid catalyzed dehydration at the temperature range of 120-190 °C. Catalyst free aqueous media demonstrated enhanced formation of furanics, while elevated temperatures led to significant saccharide isomerization. The introduction of sulfuric and formic acids maximized furfural yield and significantly reduced HMF concentration by facilitating its rehydration into levulinic acid (46 mol%). Formic acid additionally substantially enhanced formation of anhydrosaccharides. An excellent correlation between modeled and experimental data enabled process optimization to maximize furanic yield in two distinct hemicellulose streams. Sulfuric acid-containing hemicellulose stream achieved the highest furfural yield after 30 minutes at 238 °C, primarily due to the high Ea for pentose dehydration (150 - 160 kJmol-1). Contrarily, formic acid-containing hemicellulose stream enabled maximal furfural yield at more moderate temperature and extended reaction time due to its lower Ea for the same reaction step (115 - 125 kJmol-1).

Physical Treatments Modified the Functionality of Carrot Pomace.

This study addressed the critical issue of food waste, particularly focusing on carrot pomace, a by-product of carrot juice production, and its potential reutilization. Carrot pomace, characterized by high dietary fiber content, presents a sustainable opportunity to enhance the functional properties of food products. The effects of physical pretreatments-high shearing (HS), hydraulic pressing (HP), and their combination (HSHP)-alongside two drying methods (freeze-drying and dehydration) on the functional, chemical, and physical properties of carrot pomace were explored. The results indicated significant enhancements in water-holding capacity, fat-binding capacity, and swelling capacity, particularly with freeze-drying. Freeze-dried pomace retained up to 33% more carotenoids and demonstrated an increase of up to 22% in water-holding capacity compared to dehydrated samples. Freeze-dried pomace demonstrated an increase of up to 194% in fat-binding capacity compared to dehydrated samples. Furthermore, HSHP pretreatment notably increased the swelling capacity of both freeze-dried (54%) and dehydrated pomace (35%) compared to pomace without pretreatments. Freeze-drying can enhance the functional properties of dried carrot pomace and preserve more carotenoids. This presents an innovative way for vegetable juice processors to repurpose their processing by-products as functional food ingredients, which can help reduce food waste and improve the dietary fiber content and sustainability of food products.

Intentional vomiting as a rare cause of hypercalcemia and consequent acute renal failure: a case report.

Two most common causes of elevated serum calcium levels, which together account for nearly 90% of all cases, are primary hyperparathyroidism and malignancy. Thus, it is necessary to consider other disorders in the diagnostic evaluation of patients with hypercalcemia. We report the case of a 40-year-old female patient with an intellectual disability who was admitted to the Emergency Department with severe symptomatic hypercalcemia and acute renal failure, caused by recurrent intentional vomiting. The aim of this report is to help clinicians make an accurate diagnosis by considering recurrent vomiting habits as a potential cause of hypercalcemia and acute renal failure. Our case provides a comprehensive diagnostic work-up and multidisciplinary treatment strategies for patients with symptomatic hypercalcemia.

Transcription Cofactor CsMBF1c Enhances Heat Tolerance of Cucumber and Interacts with Heat-Related Proteins CsNFYA1 and CsDREB2.

Multiprotein bridging factor 1 (MBF1) is a very important transcription factor (TF) in plants, whose members influence numerous defense responses. Our study found that MBF1c in Cucurbitaceae was highly conserved. CsMBF1c expression was induced by temperature, salt stress, and abscisic acid (ABA) in cucumber. Overexpressed CsMBF1c enhanced the heat resistance of a cucumber, and the Csmbf1c mutant showed decreased resistance to high temperatures (HTs). CsMBF1c played an important role in stabilizing the photosynthetic system of cucumber under HT, and its expression was significantly associated with heat-related TFs and genes related to protein processing in the endoplasmic reticulum (ER). Protein interaction showed that CsMBF1c interacted with dehydration-responsive element binding protein 2 (CsDREB2) and nuclear factor Y A1 (CsNFYA1). Overexpression of CsNFYA1 in Arabidopsis improved the heat resistance. Transcriptional activation of CsNFYA1 was elevated by CsMBF1c. Therefore, CsMBF1c plays an important regulatory role in cucumber's resistance to high temperatures.

Water Versus Electrolyte Rehydration on Vocal Fold Osmotic and Oxidative Stress Gene Expression.

OBJECTIVES: Systemic dehydration may induce osmotic and oxidative stress in the vocal folds, but our knowledge of the biology and mitigation with rehydration is limited. The purpose of this experiment was to evaluate whether systemic dehydration induces vocal fold oxidative and osmotic stress and to compare the impact of rehydration by water intake versus electrolyte intake on osmotic and oxidative stress-related gene expression. METHODS: Four-month-old male Sprague-Dawley rats (N = 32) underwent water restriction. Rehydration was achieved with ad libitum access to water or electrolytes for 24 hours. Rats were divided into four groups: euhydration control, dehydration-only, dehydration followed by either water or electrolyte rehydration (n = 8/group). Gene expression was assessed via RT2 Gene Expression Profiler arrays. RESULTS: With respect to oxidative stress, 10 genes were upregulated and 2 were downregulated after vocal fold dehydration compared with the euhydrated control. Concerning osmotic stress, six genes were upregulated with dehydration only, six genes were upregulated following rehydration with water, whereas a single gene was upregulated with electrolyte rehydration. All genes with significantly different expression between the rehydration groups showed lower expression with electrolytes compared with water. CONCLUSIONS: The results support a potential role of oxidative and osmotic stresses in vocal folds related to systemic dehydration. The differences in stress-related gene expression in vocal fold tissue between rehydration with electrolytes or water, albeit modest, suggest that both rehydration options offer clinical utility to subjects experiencing vocal fold dehydration with preliminary evidence that electrolytes may be more effective than water in resolving osmotic stress. LEVELS OF EVIDENCE: NA (prospective animal study) Laryngoscope, 2024.

Electrodeposition of cellulose nanofibers as an efficient dehydration method.

Dehydration of a cellulose nanofiber (CNF)/water dispersion requires large amounts of energy and time due to the high hydrophilicities and high specific surface areas of the CNFs. Various dehydration methods have been proposed for CNF/water dispersions; however, an efficient dehydration method for individually dispersed CNFs is needed. Here, electrodeposition of CNFs was evaluated as a dehydration method. Electrodeposition at a DC voltage of 10 V on a 0.2 wt% CNF/water dispersion resulted in a concentration of ∼1.58 wt% in 1 h. The dehydration energy efficiency was ∼300 times greater than that of dehydration by evaporation. The concentrated CNF hydrogels recovered after electrodeposition were redispersed with a simple neutralization process, and clear transparent films were obtained by drying after redispersion. This work provides a new method for dehydration and reuse of individually dispersed CNF/water dispersions and provides new insights into control of the hierarchical structures of CNFs by electrodeposition.

Respiratory Syncytial Virus in a Child With Dravet Syndrome: A Case Report.

The objective of this case report is to describe and document a case of respiratory syncytial virus (RSV) in a pediatric patient with Dravet syndrome (DS), also known as severe myoclonic epilepsy of infancy. Febrile seizures are often a complication in a patient with DS and can lead to status epilepticus, necessitating measures to prevent triggers such as fever, electrolyte imbalance, or dehydration. An increased awareness and understanding of DS can facilitate the identification of warning signs. A two-year-old female with a past medical history of DS with focal and generalized features presented to the pediatric emergency department (ED) with a five-day history of cough, fever, and decreased oral intake. The patient's parents accompanied her and expressed concerns regarding the risk of seizures associated with a rise in body temperature, as they had been alternating between acetaminophen and ibuprofen to manage her fever with a maximum recorded temperature of 101.5℉. She exhibited signs of increased work of breathing, necessitating the administration of supplemental oxygen via nasal cannula. Blood samples were obtained and resulted in the development of metabolic acidosis. A respiratory panel confirmed the presence of an RSV infection, promoting the administration of breathing treatment with albuterol and ipratropium bromide. The patient was admitted for dehydration and was started on ½ normal saline/potassium chloride 20 mEq at 40 mL/hr. Additionally, her home medication regimen was resumed to minimize the risk of seizures. Given the patient's complications and increased risk of seizure, she was transferred to higher-level care where her status improved after the placement of a percutaneous endoscopic gastrostomy (PEG). This case underscores the complexities involved in managing patients with DS, particularly when complicated by respiratory illness and electrolyte imbalances that can lower the seizure threshold. This patient received a combination of diet and medications to prevent seizures, as well as allow for recovery and correction of the underlying metabolic acidosis. The transfer to a higher level of care in this case was necessary to allow for the specialized resources and expertise needed to handle this case.

Characteristics and preventability of medication-related admissions for acute kidney injury and dehydration in elderly patients.

PURPOSE: Patients with impaired renal function using medication that affects glomerular filtration rate are at increased risk of developing acute kidney injury (AKI) leading to hospital admissions. The risk increases during periods of dehydration due to diarrhoea, vomiting or fever (so-called "sick days"), or high environmental temperatures (heat wave). This study aims to gain insight into the characteristics and preventability of medication-related admissions for AKI and dehydration in elderly patients. METHODS: Retrospective case series study in patients aged ≥ 65 years with admission for acute kidney injury, dehydration or electrolyte imbalance related to dehydration that was defined as medication-related. General practitioner's (GP) patient records including medication history and hospital discharge letters were available. For each admission, patient and admission characteristics were collected to review the patient journey. A case-by-case assessment of preventability of hospital admissions was performed. RESULTS: In total, 75 admissions were included. Most prevalent comorbidities were hypertension, diabetes, and known impaired renal function. Diuretics and RAS-inhibitors were the most prevalent medication combination. Eighty percent of patients experienced non-acute onset of symptoms and 60% had contacted their GP within 2 weeks prior to admission. Around 40% (n = 29) of admissions were considered potentially preventable if pharmacotherapy had been timely and adequately adjusted. CONCLUSION: A substantial proportion of patients admitted with AKI or dehydration experience non-acute onset of symptoms and had contacted their GP within 2 weeks prior to admission. Timely adjusting of medication in these patients could have potentially prevented a considerable number of admissions.

Optimizing Recovery in Elderly Patients: Anabolic Benefits of Glucose Supplementation during the Rehydration Period.

BACKGROUND: Since many acutely admitted older adults display signs of dehydration, treatment using balanced crystalloids is an important part of medical care. Additionally, many of these patients suffer from chronic malnutrition. We speculated that the early addition of glucose might ameliorate the hospital-related drop of caloric intake and modify their catabolic status. METHODS: We included patients 78 years and older, admitted acutely for non-traumatic illnesses. The patients were randomized into either receiving balanced crystalloid (PlasmaLyte; group P) or balanced crystalloid enriched with 100 g of glucose per liter (group G). The information about fluid balance and levels of minerals were collected longitudinally. RESULTS: In the G group, a significantly higher proportion of patients developed signs of refeeding syndrome, i.e., drops in phosphates, potassium and/or magnesium when compared to group P (83.3 vs. 16.7%, p < 0.01). The drop in phosphate levels was the most pronounced. The urinalysis showed no differences in the levels of these minerals in the urine, suggesting their uptake into the cells. There were no differences in the in-hospital mortality or in the 1-year mortality. CONCLUSION: The short-term administration of balanced crystalloids with glucose induced an anabolic shift of electrolytes in acutely admitted older adults.

Association between Urine Specific Gravity as a Measure of Hydration Status and Risk of Type 2 Diabetes: The Kailuan Prospective Cohort Study.

Diabetes, especially type 2 diabetes (T2D), poses an unprecedented challenge to global public health. Hydration status also plays a fundamental role in human health, especially in people with T2D, which is often overlooked. This study aimed to explore the longitudinal associations between hydration status and the risk of T2D among the Chinese population. This study used data from the large community-based Kailuan cohort, which included adults who attended physical examinations from 2006 to 2007 and were followed until 2020. A total of 71,526 participants who eventually met the standards were divided into five hydration-status groups based on their levels of urine specific gravity (USG). Multivariable and time-dependent Cox proportional hazards models were employed to evaluate the associations of baseline and time-dependent hydration status with T2D incidence. Restricted cubic splines (RCS) analysis was used to examine the dose-response relationship between hydration status and the risk of T2D. Over a median 12.22-year follow-up time, 11,804 of the participants developed T2D. Compared with the optimal hydration-status group, participants with dehydration and severe dehydration had a significantly increased risk of diabetes, with adjusted hazard ratios (95% CI) of 1.30 (1.04-1.63) and 1.38 (1.10-1.74). Time-dependent analyses further confirmed the adverse effects of impending dehydration, dehydration, and severe dehydration on T2D incidence by 16%, 26%, and 33% compared with the reference group. Inadequate hydration is significantly associated with increased risks of T2D among Chinese adults. Our findings provided new epidemiological evidence and highlighted the potential role of adequate hydration status in the early prevention of T2D development.

Relative merits of offering a milk replacer, glucose-electrolyte or whey-based diet on the blood composition and health of unweaned calves after transport.

The objective of this randomized controlled trial was to assess the relative merits of offering unweaned calves 3 different types of diets to meet energy and water deficits that can occur during journeys. Six young unweaned male Holstein calves were randomly selected from within 2 body weight ranges (median 48 and 42 kg) from each of 29 loads (total n = 174 calves) transported from an auction market or a collection center to a calf sorting center before transport to a veal unit. The calves were then randomly allocated to one of 3 dietary treatments (n = 58 calves/dietary treatment). They were offered either a milk replacer diet (M), a glucose-electrolyte diet (G) or a whey-based diet with added electrolytes (W). The ability of these diets to provide sufficient nutrient energy to restore vigor, avoid hypoglycaemia and clinical signs of dehydration without increasing the risk of diarrhea was assessed. A clinical assessment of dehydration, health and vigor was made, and the calves were blood sampled before feeding, then 2 h and 4 h after feeding. The plasma glucose concentration was increased 2 h and 4 h after feeding the M and W diets. The increases in plasma glucose concentration were greater 2 and 4 h after (a) feeding the M than after the W diet and (b) feeding the M and W diets than after the G diet. Back-transformed means and 95% Confidence Intervals (CI) for the ratio of the plasma glucose concentration at 4 h compared with 0 h for the milk replacer, glucose-electrolytes and whey-based diets were 1.2 mM CI 1.21, 1.35; 0.95 mM CI 0.92, 0.97; and 1.09 mM CI 1.06, 1.14, respectively. There was no effect of diet on the change in serum total protein concentration between before feeding and 2 and 4 h after feeding. The serum osmolality was lower 2 h after feeding the G diet. The fall in serum osmolality was greater 2 h after feeding the G diet than after feeding the M and W diets. The changes in the serum osmolality between before feeding and 2 h after feeding for the milk replacer, glucose-electrolytes and whey-based diets were -0.68 mosmol CI -3.27, 1.91; -5.23 mosmol CI -7.82, and -2.64; -0.13 mosmol CI -2.77, 2.51, respectively. The diet offered at the sorting center had no effect on subsequent growth on the veal rearing farm between arrival and slaughter (milk replacer 1.22 kg/d, CI 1.17, 1.28; glucose-electrolyte diet 1.23 kg/d. CI 1.18, 1.28; whey-based diet 1.28 kg/d CI 1.23, 1.33). The M diet provided the calves with nutrients and water to replace energy and water deficits that had accumulated before arrival at the sorting center, and these dietary benefits were still apparent 4 h after feeding. The benefits of the W diet were similar to those of the M diet, but the M diet was better able to assist the calves in maintaining their plasma glucose concentration 4 h after feeding than the W diet. The G diet had some short-term benefits in providing energy and assistance to the calves to recover from dehydration, as indicated by a decrease in serum osmolality. However, the G diet was clearly inferior to the M and W diets in providing sufficient energy to assist the calves in recovering from the effects of transport and fasting. During the 4-h after feeding, no adverse effects of offering the calves the M or W diets were observed. The benefits of the W diet in replacing energy and water deficits were similar to those of the M diet, but the M diet was better able to assist the calves in maintaining their blood glucose concentration 4 h after feeding than the W diet.

Is the NICE Guideline for maintenance fluid therapy in adults in hospital appropriate?

BACKGROUND AND AIMS: The National Institute for Health and Care Excellence's (NICE) Guideline for Maintenance Fluid Therapy in Adults in Hospital is widely used, but the recommendations have not been evaluated properly. In this study, we investigated whether the recommendation of providing 25-30 mL/kg/day of fluid and 1 mmol/kg each of sodium and potassium is sufficient for human needs. METHODS: First, we calculated the distribution of fluid between the extracellular fluid volume (ECV) and intracellular fluid volume (ICV) during a cross-over infusion experiment where 12 volunteers received 25 mL/kg/day of either a high-sodium (154 mmol/L) or low-sodium (54 mmol/L) solution over 48 h. Second, urine samples from 719 volunteers and clinical patients were used to quantify their renal water conservation and excretion of sodium and potassium. Third, retrospective analysis of a diet study was used to extrapolate how large the fluid intake and the electrolyte excretion likely had been in the 719 volunteers and hospital patients who delivered urine. RESULTS: The high-sodium fluid maintained the ECV but the ICV had decreased by 1.3 L after 48 h. The low-sodium fluid resulted in a volume deficit of 1.7 L that equally affected the ECV and the ICV. Regression equations based on the diet study suggested that the daily intake of water in the 719 subjects averaged 2.6 L and that 2 mmol/kg of sodium and 1 mmol/kg of potassium was excreted. CONCLUSION: The NICE guideline recommends too little water and sodium for a human to adequately maintain the ECV and ICV. CLINICAL TRIAL REGISTRATIONS: EudraCT 2016-001846-24 and ISRCTN 12215472.

Efficient determination of critical water activity and classification of hydrate-anhydrate stability relationship.

For a pair of hydrated and anhydrous crystals, the hydrate is more stable than the anhydrate when the water activity is above the critical water activity (awc). Conventional methods to determine awc are based on either hydrate-anhydrate competitive slurries at different aw or solubilities measured at different temperatures. However, these methods are typically resource-intensive and time-consuming. Here, we present simple and complementary solution- and solid-based methods and illustrate them using carbamazepine and theophylline. In the solution-based method, awc can be predicted using intrinsic dissolution rate (IDR) ratio or solubility ratio of the hydrate-anhydrate pair measured at a known water activity. In the solid-based method, awc is predicted as a function of temperature from the dehydration temperature and enthalpy obtained by differential scanning calorimetry (DSC) near a water activity of unity. For carbamazepine and theophylline, the methods yielded awc values in good agreement with those from the conventional methods. By incorporating awc as an additional variable, the hydrate-anhydrate relationship is categorized into four classes based on their dehydration temperature (Td) and enthalpy (ΔHd) in analogy with the monotropy/enantiotropy classification for crystal polymorphs. In Class 1 (ΔHd< 0 and Td ≥ 373 K), no awc exists. In Class 2 (ΔHd>0andTd≥373K), awc always exists under conventional crystallization conditions. In Class 3 (ΔHd<0andTd<373K), awc exists when T>Td. In Class 4 (ΔHd>0andTd<373K), awc exists only when T

Glyceraldehyde metabolism in mouse brain and the entry of blood-borne glyceraldehyde into the brain.

D-Glyceraldehyde, a reactive aldehyde metabolite of fructose and glucose, is neurotoxic in vitro by forming advanced glycation end products (AGEs) with neuronal proteins. In Alzheimer's disease brains, glyceraldehyde-containing AGEs have been detected intracellularly and in extracellular plaques. However, little information exists on how the brain handles D-glyceraldehyde metabolically or if glyceraldehyde crosses the blood-brain barrier from the circulation into the brain. We injected [U-13C]-D-glyceraldehyde intravenously into awake mice and analyzed extracts of serum and brain by 13C nuclear magnetic resonance spectroscopy. 13C-Labeling of brain lactate and glutamate indicated passage of D-glyceraldehyde from blood to brain and glycolytic and oxidative D-glyceraldehyde metabolism in brain cells. 13C-Labeling of serum glucose and lactate through hepatic metabolism of [U-13C]-D-glyceraldehyde could not explain the formation of 13C-labeled lactate and glutamate in the brain. Cerebral glyceraldehyde dehydrogenase and reductase activities, leading to the formation of D-glycerate and glycerol, respectively, were 0.27-0.28 nmol/mg/min; triokinase, which phosphorylates D-glyceraldehyde to D-glyceraldehyde-3-phosphate, has been demonstrated previously at low levels. Thus, D-glyceraldehyde metabolism toward glycolysis could proceed both through D-glycerate, glycerol, and D-glyceraldehyde-3-phosphate. The aldehyde group of D-glyceraldehyde was overwhelmingly hydrated into a diol in aqueous solution, but the diol dehydration rate greatly exceeded glyceraldehyde metabolism and did not restrict it. We conclude that (1) D-glyceraldehyde crosses the blood-brain barrier, and so blood-borne glyceraldehyde could contribute to AGE formation in the brain, (2) glyceraldehyde is taken up and metabolized by brain cells. Metabolism thus constitutes a detoxification mechanism for this reactive aldehyde, a mechanism that may be compromised in disease states.

Dehydration of Organic Solvents from Ternary Mixtures Containing Toluene/Methanol/Water by Pervaporation.

The separation of a toluene/methanol/water ternary mixture is a difficult task due to the toluene/water and toluene/methanol azeotropes. In this article, low-energy pervaporation is proposed for the separation of the ternary azeotrope toluene-methanol-water. This work investigates the effects of feed temperature, feed flow rate, and vacuum on pervaporation and compares the energy consumption of pervaporation with that of distillation. The results showed that at the optimized flow rate of 50 L/h and a permeate side vacuum of 60 kPa at 50 °C, the water and methanol content in the permeate was about 63.2 wt.% and 36.8 wt.%, respectively, the water/ methanol separation factor was 24.04, the permeate flux was 510.7 g/m2·h, the water content in the feed out was reduced from 2.5 wt.% to less than 0.66 wt.%, and the dehydration of toluene methanol could be realized. Without taking into account the energy consumption of pumps and other power equipment, pervaporation requires an energy consumption of 43.53 kW·h to treat 1 ton of raw material, while the energy consumption of distillation to treat 1 ton of raw material is about 261.5 kW·h. Compared to the existing distillation process, the pervaporation process consumes much less energy (about one-sixth of the energy consumption of distillation). There is almost no effect on the surface morphology and chemical composition of the membrane before and after use. The method provides an effective reference for the dehydration of organic solvents from ternary mixtures containing toluene/methanol/water.

Experimental study of different dehydration methods in the process of preparing frozen brain sections.

This study aimed to provide a recommendable protocol for the preparation of brain cryosections of rats to reduce and avoid ice crystals. We have designed five different dewatering solutions (Scheme 1: dehydrate with 15%, 20%, and 30% sucrose-phosphate-buffered saline solution; Scheme 2: 20% sucrose and 30% sucrose; Scheme 3: 30% sucrose; Scheme 4: 10%, 20%, and 30% sucrose; and Scheme 5: the tissue was dehydrated with 15% and 30% sucrose polyacetate I until it sank to the bottom, followed by placement in 30% sucrose polyacetate II) to minimize the formation of ice crystals. Cryosections from different protocols were stained with Nissl staining and compared with each other by density between cells and the distance of intertissue spaces. The time required for the dehydration process from Scheme 1 to Scheme 5 was 24, 23, 24, 24, and 33 h, respectively. Density between cells gradually decreased from Scheme 1 to Scheme 5, and the distance of intertissue spaces was differentiated and irregular in different schemes according to the images of Nissl staining. We recommend the dewatering method of Scheme 4 (the brain tissues were dehydrated in 10%, 20% and 30% sucrose solution in turn until the tissue samples were completely immersed in the solution and then immersed in the next concentration solution for dehydration).