Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 66
Filter
1.
Front Endocrinol (Lausanne) ; 15: 1287255, 2024.
Article in English | MEDLINE | ID: mdl-38449848

ABSTRACT

Growing evidence shows that maternal nutrition from preconception until lactation has an important effect on the development of non-communicable diseases in the offspring. Biological responses to environmental stress during pregnancy, including undernutrition or overnutrition of various nutrients, are transmitted in part by DNA methylation. The aim of the present narrative review is to summarize literature data on altered DNA methylation patterns caused by maternal macronutrient or vitamin intake and its association with offspring's phenotype (obesity and related metabolic changes). With our literature search, we found evidence for the association between alterations in DNA methylation pattern of different genes caused by maternal under- or overnutrition of several nutrients (protein, fructose, fat, vitamin D, methyl-group donor nutrients) during 3 critical periods of programming (preconception, pregnancy, lactation) and the development of obesity or related metabolic changes (glucose, insulin, lipid, leptin, adiponectin levels, blood pressure, non-alcoholic fatty liver disease) in offspring. The review highlights that maternal consumption of several nutrients could individually affect the development of offspring's obesity and related metabolic changes via alterations in DNA methylation.


Subject(s)
DNA Methylation , Obesity , Female , Pregnancy , Humans , Obesity/genetics , Diet , Nutrients , Nutritional Status
2.
Nutrients ; 15(8)2023 Apr 19.
Article in English | MEDLINE | ID: mdl-37111184

ABSTRACT

Preterm infants have low circulating levels of leptin, a key trophic hormone that influences growth and development. While the clinical importance of prematurity-associated leptin deficiency is undefined, recent preclinical and clinical investigations have shown that targeted enteral leptin supplementation can normalize neonatal leptin levels. We tested the hypothesis that, independent of growth velocity, prematurity-related neonatal leptin deficiency predicts adverse cardiovascular and neurodevelopmental outcomes. In a planned 2-year longitudinal follow-up of 83 preterm infants born at 22 to 32 weeks' gestation, we obtained blood pressures from 58 children and the Ages & Stages Questionnaire (ASQ-3) for 66 children. Based on univariate analysis, blood pressures correlated with gestational age at birth (R = 0.30, p < 0.05) and weight gain since discharge (R = 0.34, p < 0.01). ASQ-3 scores were significantly higher in female than male children. Utilizing best subset regression with Mallows' Cp as the criterion for model selection, higher systolic blood pressure was predicted by rapid postnatal weight gain, later gestation at delivery and male sex (Cp = 3.0, R = 0.48). Lower ASQ-3 was predicted by lower leptin levels at 35 weeks postmenstrual age, earlier gestation at delivery and male sex (Cp = 2.9, R = 0.45). Children that had leptin levels above 1500 pg/mL at 35 weeks postmenstrual age had the highest ASQ-3 scores at 2 years. In conclusion, independent of growth velocity, higher leptin levels at 35 weeks' gestation are associated with better developmental assessment scores in early childhood. While longer-term follow-up of a larger cohort is needed, these findings support investigations that have suggested that targeted neonatal leptin supplementation could improve the neurodevelopmental outcomes of preterm infants.


Subject(s)
Infant, Premature , Leptin , Infant , Child , Humans , Infant, Newborn , Child, Preschool , Male , Female , Child Development/physiology , Gestational Age , Weight Gain
3.
Nutrients ; 15(6)2023 Mar 19.
Article in English | MEDLINE | ID: mdl-36986206

ABSTRACT

BACKGROUND: Infants have three options for feeding: their own mother's breast milk, donor milk, or infant formula. Insulin, testosterone, total protein, and albumin levels were measured in breast milk samples from the first 6 months of lactation, in donor milk samples, and in different infant formulas. METHODS: Mothers who gave birth to term (n = 19) or preterm (n = 19) infants were recruited to collect breast milk samples during the first 6 months of lactation. The Breast Milk Collection Center (Unified Health Institution, Pécs, Hungary) provided 96 donor milk (DM) samples for analysis in our study. Insulin, testosterone, total protein, and albumin levels were measured in breast milk, donor milk, and infant formulas. RESULTS: During the first 2 months of lactation, the concentration of insulin was lower (-27.4%) while the testosterone concentration was higher (+20.8%) compared to the period between the 3rd and 6th months only in the preterm breast milk samples. The infant formulas examined did not contain insulin or testosterone. Holder pasteurization (HoP) did not influence the level of testosterone in human milk, although HoP decreased the insulin (-53.6%) and albumin (-38.6%) concentrations. CONCLUSIONS: Diet impacts the hormone intake of infants, underlining the importance of breastfeeding and the possible supplementation of formula-fed infants.


Subject(s)
Infant Formula , Milk, Human , Infant, Newborn , Infant , Female , Humans , Infant, Premature , Insulin , Testosterone , Infant Nutritional Physiological Phenomena , Breast Feeding , Albumins
4.
Ann R Coll Surg Engl ; 105(S2): S69-S74, 2023 Aug.
Article in English | MEDLINE | ID: mdl-36927165

ABSTRACT

Since the start of the pandemic, over 400 million COVID-19 swab tests have been conducted in the UK with a non-trivial number associated with skull base injury. Given the continuing use of nasopharyngeal swabs, further cases of swab-associated skull base injury are anticipated. We describe a 54-year-old woman presenting with persistent colourless nasal discharge for 2 weeks following a traumatic COVID-19 nasopharyngeal swab. A ß2-transferrin test confirmed cerebrospinal fluid (CSF) rhinorrhoea and a high-resolution sinus computed tomography (CT) scan demonstrated a cribriform plate defect. Magnetic resonance imaging showed radiological features of idiopathic intracranial hypertension (IIH): a Yuh grade V empty sella and thinned anterior skull base. Twenty-four hour intracranial pressure (ICP) monitoring confirmed raised pressures, prompting insertion of a ventriculoperitoneal shunt. The patient underwent CT cisternography and endoscopic transnasal repair of the skull base defect using a fluorescein adjuvant, without complications. A systematic search was performed to identify cases of COVID-19 swab-related injury. Eight cases were obtained, of which three presented with a history of IIH. Two cases were complicated by meningitis and were managed conservatively, whereas six required endoscopic skull base repair and one had a ventriculoperitoneal shunt inserted. A low threshold for high-resolution CT scanning is suggested for patients presenting with rhinorrhoea following a nasopharyngeal swab. The literature review suggests an underlying association between IIH, CSF rhinorrhoea and swab-related skull base injury. We highlight a comprehensive management pathway for these patients, including high-resolution CT with cisternography, ICP monitoring, shunt and fluorescein-based endoscopic repair to achieve the best standard of care.


Subject(s)
COVID-19 , Cerebrospinal Fluid Rhinorrhea , Fractures, Bone , Pseudotumor Cerebri , Female , Humans , Middle Aged , COVID-19/complications , Cerebrospinal Fluid Rhinorrhea/etiology , Skull Base , Pseudotumor Cerebri/complications , Fractures, Bone/complications , Nasopharynx/diagnostic imaging , Fluoresceins
5.
J Chem Theory Comput ; 19(1): 174-189, 2023 Jan 10.
Article in English | MEDLINE | ID: mdl-36576419

ABSTRACT

Several approximations are introduced and tested to reduce the computational expenses of the explicitly correlated coupled-cluster singles and doubles with perturbative triples [CCSD(T)] method for both closed and open-shell species. First, the well-established frozen natural orbital (FNO) technique is adapted to explicitly correlated CC approaches. Second, our natural auxiliary function (NAF) scheme is employed to reduce the size of the auxiliary basis required for the density fitting approximation regularly used in explicitly correlated calculations. Third, a new approach, termed the natural auxiliary basis (NAB) approximation, is proposed to decrease the size of the auxiliary basis needed for the expansion of the explicitly correlated geminals. The performance of the above approximations and that of the combined FNO-NAF-NAB approach are tested for atomization and reaction energies. Our results show that overall speedups of 7-, 5-, and 3-times can be achieved with double-, triple-, and quadruple-ζ basis sets, respectively, without any loss in accuracy. The new method can provide, e.g., reaction energies and barrier heights well within chemical accuracy for molecules with more than 40 atoms within a few days using a few dozen processor cores, and calculations with 50+ atoms are still feasible. These routinely affordable computations considerably extend the reach of explicitly correlated CCSD(T).

6.
Cell Mol Life Sci ; 79(9): 471, 2022 Aug 06.
Article in English | MEDLINE | ID: mdl-35932293

ABSTRACT

In synapses that show signs of local apoptosis and mitochondrial stress and undergo neuro-immunological synapse pruning, an increase in the levels of the presynaptic protein, neuronal-specific septin-3 can be observed. Septin-3 is a member of the septin GTPase family with the ability to form multimers and contribute to the cytoskeleton. However, the function of septin-3 remains elusive. Here, we provide evidence that septin-3 is capable of binding the most-studied autophagy protein Atg8 homolog microtubule-associated protein 1 light chain 3B (LC3B), besides another homolog, GABA receptor-associated protein-like 2 (GABARAPL2). Moreover, we demonstrate that colocalization of septin-3 and LC3B increases upon chemical autophagy induction in primary neuronal cells. Septin-3 is accumulated in primary neurons upon autophagy enhancement or blockade, similar to autophagy proteins. Using electron microscopy, we also show that septin-3 localizes to LC3B positive membranes and can be found at mitochondria. However, colocalization results of septin-3 and the early mitophagy marker PTEN-induced kinase 1 (PINK1) do not support that binding of septin-3 to mitochondria is mitophagy related. We conclude that septin-3 correlates with synaptic/neuronal autophagy, binds Atg8 and localizes to autophagic membranes that can be enhanced with chemical autophagy induction. Based on our results, elevated septin-3 levels might indicate enhanced or impeded autophagy in neurons.


Subject(s)
Autophagosomes , Septins , Autophagosomes/metabolism , Autophagy , Microtubule-Associated Proteins/metabolism , Mitophagy , Neurons/metabolism , Septins/metabolism
7.
Mol Ther Nucleic Acids ; 29: 116-132, 2022 Sep 13.
Article in English | MEDLINE | ID: mdl-35795486

ABSTRACT

Effective systemic delivery of small interfering RNAs (siRNAs) to tissues other than liver remains a challenge. siRNAs are small (∼15 kDa) and therefore rapidly cleared by the kidneys, resulting in limited blood residence times and tissue exposure. Current strategies to improve the unfavorable pharmacokinetic (PK) properties of siRNAs rely on enhancing binding to serum proteins through extensive phosphorothioate modifications or by conjugation of targeting ligands. Here, we describe an alternative strategy for enhancing blood and tissue PK based on dynamic modulation of the overall size of the siRNA. We engineered a high-affinity universal oligonucleotide anchor conjugated to a high-molecular-weight moiety, which binds to the 3' end of the guide strand of an asymmetric siRNA. Data showed a strong correlation between the size of the PK-modifying anchor and clearance kinetics. Large 40-kDa PK-modifying anchors reduced renal clearance by ∼23-fold and improved tissue exposure area under the curve (AUC) by ∼26-fold, resulting in increased extrahepatic tissue retention (∼3- to 5-fold). Furthermore, PK-modifying oligonucleotide anchors allowed for straightforward and versatile modulation of blood residence times and biodistribution of a panel of chemically distinct ligands. The effects were more pronounced for conjugates with low lipophilicity (e.g., N-Acetylgalactosamine [GalNAc]), where significant improvement in uptake by hepatocytes and dose-dependent silencing in the liver was observed.

8.
J Biol Chem ; 298(7): 102113, 2022 07.
Article in English | MEDLINE | ID: mdl-35690144

ABSTRACT

Complement component C1q is a protein complex of the innate immune system with well-characterized binding partners that constitutes part of the classical complement pathway. In addition, C1q was recently described in the central nervous system as having a role in synapse elimination both in the healthy brain and in neurodegenerative diseases. However, the molecular mechanism of C1q-associated synapse phagocytosis is still unclear. Here, we designed monomer and multimer protein constructs, which comprised the globular interaction recognition parts of mouse C1q (globular part of C1q [gC1q]) as single-chain molecules (sc-gC1q proteins) lacking the collagen-like effector region. These molecules, which can competitively inhibit the function of C1q, were expressed in an Escherichia coli expression system, and their structure and capabilities to bind known complement pathway activators were validated by mass spectrometry, analytical size-exclusion chromatography, analytical ultracentrifugation, CD spectroscopy, and ELISA. We further characterized the interactions between these molecules and immunoglobulins and neuronal pentraxins using surface plasmon resonance spectroscopy. We demonstrated that sc-gC1qs potently inhibited the function of C1q. Furthermore, these sc-gC1qs competed with C1q in binding to the embryonal neuronal cell membrane. We conclude that the application of sc-gC1qs can reveal neuronal localization and functions of C1q in assays in vivo and might serve as a basis for engineering inhibitors for therapeutic purposes.


Subject(s)
Complement C1q , Complement Pathway, Classical , Animals , Enzyme-Linked Immunosorbent Assay , Mice
9.
Life (Basel) ; 12(5)2022 Apr 19.
Article in English | MEDLINE | ID: mdl-35629277

ABSTRACT

Maternal exposure to some dietary and environmental factors during embryonic development can affect offspring's phenotype and, furthermore, the risk of developing diseases later in life. One potential mechanism responsible for this early programming may be the modification of the epigenome, such as DNA methylation. Methyl-group donors are essential for DNA methylation and are shown to have an important role in fetal development and later health. The main goal of the present review is to summarize the available literature data on the epigenetic effect (DNA methylation) of maternal methyl-group donor availability on reproductivity, perinatal outcome, and later health of the offspring. In our literature search, we found evidence for the association between alterations in DNA methylation patterns caused by different maternal methyl-group donor (folate, choline, methionine, betaine) intake and reproductivity, birth weight, neural tube defect, congenital heart defect, cleft lip and palate, brain development, and the development of obesity and associated non-communicable diseases in later life. We can conclude that maternal methyl-group donor availability could affect offspring's health via alterations in DNA methylation and may be a major link between early environmental exposure and the development of diseases in the offspring. However, still, further studies are necessary to confirm the associations and causal relationships.

10.
J Chem Phys ; 156(18): 184703, 2022 May 14.
Article in English | MEDLINE | ID: mdl-35568547

ABSTRACT

The adsorption of acetamide on low density amorphous (LDA) ice is investigated by grand canonical Monte Carlo computer simulations at the temperatures 50, 100, and 200 K, characteristic of certain domains of the interstellar medium (ISM). We found that the relative importance of the acetamide-acetamide H-bonds with respect to the acetamide-water ones increases with decreasing temperature. Thus, with decreasing temperature, the existence of the stable monolayer, characterizing the adsorption at 200 K, is gradually replaced by the occurrence of marked multilayer adsorption, preceding even the saturation of the first layer at 50 K. While isolated acetamide molecules prefer to lay parallel to the ice surface to maximize their H-bonding with the surface water molecules, this orientational preference undergoes a marked change upon saturation of the first layer due to increasing competition of the adsorbed molecules for H-bonds with water and to the possibility of their H-bond formation with each other. As a result, molecules stay preferentially perpendicular to the ice surface in the saturated monolayer. The chemical potential value corresponding to the point of condensation is found to decrease linearly with increasing temperature. We provide, in analogy with the Clausius-Clapeyron equation, a thermodynamic explanation of this behavior and estimate the molar entropy of condensed phase acetamide to be 34.0 J/mol K. For the surface concentration of the saturated monolayer, we obtain the value 9.1 ± 0.8 µmol/m2, while the heat of adsorption at infinitely low surface coverage is estimated to be -67.8 ± 3.0 kJ/mol. Our results indicate that the interstellar formation of peptide chains through acetamide molecules, occurring at the surface of LDA ice, might well be a plausible process in the cold (i.e., below 50 K) domains of the ISM; however, it is a rather unlikely scenario in its higher temperature (i.e., 100-200 K) domains.


Subject(s)
Ice , Water , Acetamides , Adsorption , Computer Simulation , Water/chemistry
11.
Life (Basel) ; 12(4)2022 Apr 14.
Article in English | MEDLINE | ID: mdl-35455075

ABSTRACT

Breastfeeding is widely supported in clinical and home practices, and it is known that different forms of infant feeding differ in hormone content. Thyroid hormones have essential physiological roles. In our study, we examined thyroid-stimulating hormone (TSH), thyroxine, and albumin levels in breast milk produced for term (n = 16) or preterm (n = 15) infants throughout the first 6 months of lactation. Moreover, we analyzed these components in donor human milk and in three different infant formulas. Term and preterm breast milk samples were collected monthly. The two groups had similar levels of TSH (18.4 ± 1.4 vs. 24.7 ± 2.9 nU/L), but term milk contained higher amounts of thyroxine (11,245.5 ± 73.8 vs. 671.6 ± 61.2 nmol/L) during the examination period. The albumin level was significantly higher in preterm breast milk than in term breast milk (328.6 ± 17.1 vs. 264.2 ± 6.8 mg/L). In preterm breast milk we detected downward trends in the levels of TSH (-30.2%) and thyroxine (-29.2%) in the 3rd through 6th month compared to the first 2 months of lactation. Microbiological safety of donor milk was ensured by Holder pasteurization (HoP). From the Breast Milk Collection Center of Pécs, Hungary, we enrolled 44 donor mothers into the study. HoP decreased TSH (-73.8%), thyroxine (-22.4%), and albumin (-20.9%) concentrations. Infant formulas used by the Neonatal Intensive Care Unit of the University of Pécs were found to not contain the investigated hormones, but their albumin levels were similar to the breast milk samples. The present study shows the lack of thyroid hormones in infant formulas compared to human milk and raises the question of whether formula-fed infants should be supplemented with thyroid hormones.

12.
Seizure ; 94: 136-141, 2022 Jan.
Article in English | MEDLINE | ID: mdl-34906799

ABSTRACT

BACKGROUND: Studies examining epilepsy as a COVID-related death risk have come to conflicting conclusions. Our aim was to assess the prevalence of epilepsy among COVID-related deaths in Hungary. METHODS: Each COVID-19 infection case is required to be reported on a daily basis to the National Public Health Center of Hungary. This online report includes the beginning and end of the infection, as well as information on comorbidities. Death during infection is regarded as COVID-related. The anonymized data of each deceased patient are published on an information website (www.koronavirus.gov.hu) and provides up-to-date information on each patient with the date of death, the patient's sex, age, and chronic illness. RESULTS: There were 11,968 patients who died of COVID-19 in Hungary between 13 March 2020 and 23 January 2021. Among 11,686 patients with no missing values for comorbidities, 255 patients had epilepsy (2.2%). Epilepsy was much more common among those who died at a young age: 9.3% of those who died under the age of 50 had epilepsy, compared with only 1.3% in those over the age of 80. The younger an age group was, the higher was the prevalence of epilepsy. CONCLUSION: Patients who died of COVID-19 under the age of 50 were 10 to 20 times more likely to have epilepsy than what would have been expected from epidemiological data. Our results highlight the need for increased protection of young people with epilepsy from COVID-19 infection and the development of a vaccination strategy accordingly.


Subject(s)
COVID-19 , Epilepsy , Adolescent , Child , Epilepsy/epidemiology , Humans , Hungary/epidemiology , Prevalence , SARS-CoV-2
13.
JCI Insight ; 6(24)2021 12 22.
Article in English | MEDLINE | ID: mdl-34935646

ABSTRACT

siRNAs comprise a class of drugs that can be programmed to silence any target gene. Chemical engineering efforts resulted in development of divalent siRNAs (di-siRNAs), which support robust and long-term efficacy in rodent and nonhuman primate brains upon direct cerebrospinal fluid (CSF) administration. Oligonucleotide distribution in the CNS is nonuniform, limiting clinical applications. The contribution of CSF infusion placement and dosing regimen on relative accumulation, specifically in the context of large animals, is not well characterized. To our knowledge, we report the first systemic, comparative study investigating the effects of 3 routes of administration - intrastriatal (i.s.), i.c.v., and intrathecal catheter to the cisterna magna (ITC) - and 2 dosing regimens - single and repetitive via an implanted reservoir device - on di-siRNA distribution and accumulation in the CNS of Dorset sheep. CSF injections (i.c.v. and ITC) resulted in similar distribution and accumulation across brain regions. Repeated dosing increased homogeneity, with greater relative deep brain accumulation. Conversely, i.s. administration supported region-specific delivery. These results suggest that dosing regimen, not CSF infusion placement, may equalize siRNA accumulation and efficacy throughout the brain. These findings inform the planning and execution of preclinical and clinical studies using siRNA therapeutics in the CNS.


Subject(s)
Genetic Therapy/methods , RNA, Small Interfering/administration & dosage , Animals , Drug Administration Routes , Sheep
14.
Epileptic Disord ; 23(4): 633-638, 2021 Aug 01.
Article in English | MEDLINE | ID: mdl-34279235

ABSTRACT

Neuromodulation therapy -vagus nerve stimulation (VNS) and deep brain stimulation (DBS)- is one of the therapeutic options for drug-resistant epilepsy. With the increasing number of DBS implantations in women with epilepsy, it has become a burning issue whether DBS is safe in pregnancy. We report here two women with epilepsy who gave birth to healthy children with DBS therapy. We describe two cases, a 30-year-old woman and a 37-year-old woman. Both were implanted with DBS due to drug-resistant epilepsy. Both of our patients showed a significant improvement after DBS implantation and thereafter gave birth to a healthy child with DBS treatment. The severity and frequency of epileptic seizures did not change during pregnancy and after childbirth. Although a Caesarean section was performed in one case, pregnancies and births were essentially problem-free. At present, the two- and four-year-old children are healthy. Considering these cases, previously described VNS cases, and DBS cases with non-epileptic indications; we suggest that pregnancy and childbirth are safe in epilepsy patients with DBS, moreover, DBS treatment has probably no effect on foetal abnormalities or breastfeeding.


Subject(s)
Deep Brain Stimulation , Epilepsy , Vagus Nerve Stimulation , Adult , Cesarean Section , Child, Preschool , Drug Resistant Epilepsy/therapy , Epilepsy/therapy , Female , Humans , Pharmaceutical Preparations , Pregnancy , Treatment Outcome
15.
J Chem Phys ; 155(3): 034107, 2021 Jul 21.
Article in English | MEDLINE | ID: mdl-34293884

ABSTRACT

A new approach is proposed to reduce the basis set incompleteness error of the triple excitation correction in explicitly correlated coupled-cluster singles and doubles with perturbative triples calculations. Our method is similar to the intuitive triples correction approach of Knizia et al. [J. Chem. Phys. 130, 054104 (2009)] but, in contrast to the latter, is size-consistent. The new approximation is easy to implement, and its overhead is negligible with respect to the conventional (T) correction. The performance of the approach is assessed for atomization, reaction, and interaction energies as well as for bond lengths and harmonic vibrational frequencies. The advantages of its size consistency are also demonstrated.

16.
Nutrients ; 13(2)2021 Jan 28.
Article in English | MEDLINE | ID: mdl-33525560

ABSTRACT

Hormones are important biological regulators, controlling development and physiological processes throughout life. We investigated pituitary hormones such as follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL) and total protein levels during the first 6 months of lactation. Breast milk samples were collected every fourth week of lactation from mothers who gave birth to preterm (n = 14) or term (n = 16) infants. Donor milk is suggested when own mother's milk is not available; therefore, we collected breast milk samples before and after Holder pasteurization (HoP) from the Breast Milk Collection Center of Pécs, Hungary. Three infant formulas prepared in the Neonatal Intensive Care Unit of the University of Pécs were tested at three different time points. Our aim was to examine the hormone content of own mother's milk and donor milk. There were no significant changes over time in the concentrations of any hormone. Preterm milk had higher PRL (28.2 ± 2.5 vs 19.3 ± 2.3 ng/mL) and LH (36.3 ± 8.8 vs 15.9 ± 4.1 mIU/L) concentrations than term milk during the first 6 months of lactation. Total protein and FSH concentrations did not differ between preterm and term breast milk. Holder pasteurization decreased the PRL concentration (30.4 ± 1.8 vs 14.4 ± 0.6 ng/mL) and did not affect gonadotropin levels of donor milk. Infant formulas have higher total protein content than breast milk but do not contain detectable levels of pituitary hormones. Differences were detected in the content of pituitary hormones produced for preterm and term infants. Divergence between feeding options offers opportunities for improvement of nutritional guidelines for both hospital and home feeding practices.


Subject(s)
Infant, Premature/physiology , Milk, Human/physiology , Mothers , Tissue Donors , Adult , Breast Feeding , Confounding Factors, Epidemiologic , Female , Follicle Stimulating Hormone/metabolism , Humans , Infant Formula , Infant, Newborn , Luteinizing Hormone/metabolism , Male , Pasteurization
17.
J Phys Chem B ; 124(44): 9884-9897, 2020 11 05.
Article in English | MEDLINE | ID: mdl-33084342

ABSTRACT

The surface tension of all aqueous alkali halide solutions is higher than that of pure water. According to the Gibbs adsorption equation, this indicates a net depletion of these ions in the interfacial region. However, simulations and experiments show that large, soft ions, such as I-, can accumulate at the liquid/vapor interface. The presence of a loose hydration shell is usually considered to be the reason for this behavior. In this work, we perform computer simulations to characterize the liquid-vapor interface of aqueous alkali chloride and sodium halide solutions systematically, considering all ions from Li+ to Cs+ and from F- to I-. Using computational methods for the removal of surface fluctuations, we analyze the structure of the interface at a dramatically enhanced resolution, showing that the positive excess originates in the very first molecular layer and that the next 3-4 layers account for the net negative excess. With the help of a fictitious system with charge-inverted ion pairs, we also show that it is not possible to rationalize the surface affinity of ions in solutions in terms of the properties of anions and cations separately. Moreover, the surface excess is generally dominated by the smaller of the two ions.

18.
Phys Chem Chem Phys ; 22(20): 11652-11662, 2020 May 28.
Article in English | MEDLINE | ID: mdl-32406446

ABSTRACT

The changes in extensive thermodynamic quantities, such as volume, energy, Helmholtz free energy and entropy, occurring upon mixing liquid methanol with supercritical CO2, are calculated using Monte Carlo simulations and thermodynamic integration for all eight combinations of four methanol and two CO2 potential models in the entire composition range at 313 K. The obtained results are also compared with experimental data whenever possible. The transition of the system from liquid to a supercritical state is found to occur at this temperature around a CO2 mole fraction value of 0.95 with all model combinations considered. This liquid to supercritical transition is always accompanied by positive Helmholtz free energy of mixing values and, consequently, by the non-miscibility of the two components. Furthermore, both this non-miscibility around the liquid to supercritical transition and also the miscibility of the two components below this transition, in the liquid regime, are found to be primarily of the energetic rather than entropic origin; the entropy of mixing turns out to be very close to zero, and around the liquid to supercritical transition even its qualitative behaviour is strongly model dependent. Finally, it is found that the methanol expansion coefficient is not sensitive to the details of the potential models, and it is always in excellent agreement with the experimental data. On the other hand, both the volume and the energy of mixing depend strongly on the molar volume of neat CO2 in the model being used, and in this respect the TraPPE model of CO2 [J. J. Potoff and J. I. Siepmann, AIChE J., 2001, 47, 1676] performs considerably better than that of Zhang and Duan [Z. Zhang and Z. Duan, J. Chem. Phys., 2005, 122, 214507].

19.
Nutrients ; 12(3)2020 Mar 04.
Article in English | MEDLINE | ID: mdl-32143273

ABSTRACT

Our aims were to investigate the presence of pituitary glycoprotein hormones in preterm and donor milk, and to examine the effects of Holder pasteurization and refrigeration on the levels of these hormones. We measured follicle-stimulating hormone (FSH), luteinizing hormone (LH), and thyroid-stimulating hormone (TSH) in milk samples from mothers who delivered prematurely (n = 27) and in samples of mothers who delivered at term and donated milk to the Mother's Milk Bank of Iowa (n = 30). The gonadotropins and TSH were present in similar amounts within human milk produced for preterm and term infants. FSH increased 21% after refrigeration (p < 0.05), while LH declined by 39% (p < 0.05). Holder pasteurization decreased LH by 24% (p < 0.05) and increased TSH by 17% (p < 0.05). Holder pasteurization followed by refrigeration resulted in a 21% increase in FSH and a 41% decrease in LH (both p < 0.05), resulting in more than a 3-fold increase in donor milk FSH:LH ratios (p < 0.05 versus fresh donor milk). Despite structural similarities, the gonadotropins are differentially impacted by Holder pasteurization and refrigeration, and this results in marked alterations in the relative amount of FSH and LH that may be administered to preterm infants, potentially swinging hormonal balance towards ovarian hyperstimulation in females and hypogonadism in males.


Subject(s)
Food Analysis , Glycoprotein Hormones, alpha Subunit/analysis , Milk, Human/chemistry , Pasteurization , Pituitary Hormones/analysis , Refrigeration , Humans
20.
Cell Mol Life Sci ; 77(24): 5243-5258, 2020 Dec.
Article in English | MEDLINE | ID: mdl-32034429

ABSTRACT

Synaptic functional disturbances with concomitant synapse loss represent central pathological hallmarks of Alzheimer's disease. Excessive accumulation of cytotoxic amyloid oligomers is widely recognized as a key event that underlies neurodegeneration. Certain complement components are crucial instruments of widespread synapse loss because they can tag synapses with functional impairments leading to their engulfment by microglia. However, an exact understanding of the affected synaptic functions that predispose to complement-mediated synapse elimination is lacking. Therefore, we conducted systematic proteomic examinations on synaptosomes prepared from an amyloidogenic mouse model of Alzheimer's disease (APP/PS1). Synaptic fractions were separated according to the presence of the C1q-tag using fluorescence-activated synaptosome sorting and subjected to proteomic comparisons. The results raised the decline of mitochondrial functions in the C1q-tagged synapses of APP/PS1 mice based on enrichment analyses, which was verified using flow cytometry. Additionally, proteomics results revealed extensive alterations in the level of septin protein family members, which are known to dynamically form highly organized pre- and postsynaptic supramolecular structures, thereby affecting synaptic transmission. High-resolution microscopy investigations demonstrated that synapses with considerable amounts of septin-3 and septin-5 show increased accumulation of C1q in APP/PS1 mice compared to the wild-type ones. Moreover, a strong positive correlation was apparent between synaptic septin-3 levels and C1q deposition as revealed via flow cytometry and confocal microscopy examinations. In sum, our results imply that deterioration of synaptic mitochondrial functions and alterations in the organization of synaptic septins are associated with complement-dependent synapse loss in Alzheimer's disease.


Subject(s)
Alzheimer Disease/genetics , Amyloid/metabolism , Proteome/genetics , Synapses/genetics , Alzheimer Disease/pathology , Amyloid/toxicity , Amyloidogenic Proteins/genetics , Animals , Disease Models, Animal , Gene Expression Regulation/genetics , Humans , Mice , Microglia/metabolism , Microglia/pathology , Mitochondria/genetics , Mitochondria/pathology , Oligopeptides/genetics , Plaque, Amyloid/genetics , Plaque, Amyloid/pathology , Septins/genetics , Synapses/metabolism , Synapses/pathology , Synaptosomes/metabolism , Synaptosomes/pathology
SELECTION OF CITATIONS
SEARCH DETAIL
...