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1.
Exp Neurol ; 377: 114781, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38636773

RESUMO

Chronic hypoxia in utero causes intrauterine growth restriction (IUGR) of the fetus. IUGR infants are known to be at higher risk for neurodevelopmental disorders, but the mechanism is unclear. In this study, we analyzed the structure of the cerebral cortex using IUGR model rats generated through a reduced uterine perfusion pressure operation. IUGR rats exhibited thinner cerebral white matter and enlarged lateral ventricles compared with control rats. Expression of neuron cell markers, Satb2, microtubule-associated protein (MAP)-2, α-tubulin, and nestin was reduced in IUGR rats, indicating that neurons were diminished at various developmental stages in IUGR rats, from neural stem cells to mature neurons. However, there was no increase in apoptosis in IUGR rats. Cells positive for Ki67, a marker of cell proliferation, were reduced in neurons and all glial cells of IUGR rats. In primary neuron cultures, axonal elongation was impaired under hypoxic culture conditions mimicking the intrauterine environment of IUGR infants. Thus, in IUGR rats, chronic hypoxia in utero suppresses the proliferation of neurons and glial cells as well as axonal elongation, resulting in cortical thinning and enlarged lateral ventricles. Thrombopoietin (TPO), a platelet growth factor, inhibited the decrease in neuron number and promoted axon elongation in primary neurons under hypoxic conditions. Intraperitoneal administration of TPO to IUGR rats resulted in increases in the number of NeuN-positive cells and the area coverage of Satb2. In conclusion, suppression of neuronal proliferation and axonal outgrowth in IUGR rats resulted in cortical thinning and enlargement of lateral ventricles. TPO administration might be a novel therapeutic strategy for treating brain dysmaturation in IUGR infants.


Assuntos
Proliferação de Células , Retardo do Crescimento Fetal , Crescimento Neuronal , Neurônios , Fármacos Neuroprotetores , Ratos Sprague-Dawley , Trombopoetina , Animais , Retardo do Crescimento Fetal/patologia , Ratos , Neurônios/efeitos dos fármacos , Neurônios/patologia , Neurônios/metabolismo , Feminino , Proliferação de Células/efeitos dos fármacos , Gravidez , Crescimento Neuronal/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Células Cultivadas , Animais Recém-Nascidos , Córtex Cerebral/patologia , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo
2.
Neurochem Res ; 49(3): 800-813, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38112974

RESUMO

Therapeutic hypothermia (TH) provides neuroprotection. However, the cellular mechanisms underlying the neuroprotective effects of TH are not fully elucidated. Regulation of microglial activation has the potential to treat a variety of nervous system diseases. Transient receptor potential vanilloid 4 (TRPV4), a nonselective cation channel, is activated by temperature stimulus at 27-35 °C. Although it is speculated that TRPV4 is associated with the neuroprotective mechanisms of TH, the role of TRPV4 in the neuroprotective effects of TH is not well understood. In the present study, we investigated whether hypothermia attenuates microglial activation via TRPV4 channels. Cultured microglia were incubated under normothermic (37 °C) or hypothermic (33.5 °C) conditions following lipopolysaccharide (LPS) stimulation. Hypothermic conditions suppressed the expression of pro-inflammatory cytokines, inducible nitric oxide synthase, and the number of phagocytic microglia. AMP-activated protein kinase (AMPK)-NF-κB signaling was inhibited under hypothermic conditions. Furthermore, hypothermia reduced neuronal damage induced by LPS-treated microglial cells. Treatment with TRPV4 antagonist in normothermic culture replicated the suppressive effects of hypothermia on microglial activation and microglia-induced neuronal damage. In contrast, treatment with a TRPV4 agonist in hypothermic culture reversed the suppressive effect of hypothermia. These findings suggest that TH suppresses microglial activation and microglia-induced neuronal damage via the TRPV4-AMPK-NF-κB pathway. Although more validation is needed to consider differences according to age, sex, and specific central nervous system regions, our findings may offer a novel therapeutic approach to complement TH.


Assuntos
Antineoplásicos , Hipotermia , Fármacos Neuroprotetores , Humanos , NF-kappa B/metabolismo , Microglia/metabolismo , Canais de Cátion TRPV/metabolismo , Fármacos Neuroprotetores/farmacologia , Hipotermia/metabolismo , Lipopolissacarídeos/toxicidade , Proteínas Quinases Ativadas por AMP/metabolismo , Antineoplásicos/farmacologia , Óxido Nítrico/metabolismo
3.
Exp Cell Res ; 432(1): 113784, 2023 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-37730144

RESUMO

Atherosclerosis is a persistent inflammatory state that contributes significantly to cardiovascular disease, a primary cause of mortality worldwide. Enhanced lipid uptake by macrophages and their transformation into foam cells play a key role in the development of atherosclerosis. Recent studies using in vivo mouse models indicated that activation of AMPK has anti-atherosclerotic effects by upregulating the expression of cholesterol efflux transporters in foam cells and promoting cholesterol efflux. However, the pathway downstream of AMPK that contributes to elevated expression of cholesterol efflux transporters remains unclear. In this study, we found that activation of AMPK by AICAR and metformin inhibits foam cell formation via suppression of mTOR in macrophages. Specifically, activation of AMPK indirectly reduced the phosphorylation level of mTOR at Ser2448 and promoted the expression of cholesterol efflux transporters and cholesterol efflux. These inhibitory effects on foam cell formation were counteracted by mTOR activators. Metformin, a more nonspecific AMPK activator than AICAR, appears to inhibit foam cell formation via anti-inflammatory effects in addition to suppression of the mTOR pathway. The results of this study suggest that the development of new drugs targeting AMPK activation and mTOR inhibition may lead to beneficial results in the prevention and treatment of atherosclerosis.


Assuntos
Aterosclerose , Metformina , Animais , Camundongos , Proteínas Quinases Ativadas por AMP/metabolismo , Macrófagos/metabolismo , Colesterol/metabolismo , Células Espumosas , Serina-Treonina Quinases TOR/metabolismo , Metformina/farmacologia , Metformina/metabolismo , Aterosclerose/metabolismo , Transportador 1 de Cassete de Ligação de ATP/metabolismo
4.
World J Clin Cases ; 11(26): 6262-6267, 2023 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-37731562

RESUMO

BACKGROUND: Holoprosencephaly (HPE) is a congenital malformation with various degrees of incomplete separation of the cerebral hemispheres due to differentiation disorders of the forebrain. Although HPE with diabetes insipidus due to associated pituitary dysfunction has been reported, HPE with the syndrome of inappropriate antidiuretic hormone secretion (SIADH) is very rare. Tolvaptan, a vasopressin V2 receptor antagonist, is effective in adults with SIADH. However, there is no report of its efficacy in infants with SIADH. The purpose of this report is to demonstrate that tolvaptan is effective for SIADH in infants and that administration of tolvaptan eliminates the need for restriction of water intake and sodium administration. CASE SUMMARY: A 2414-g female infant was born at 38 wk by normal vaginal delivery. Facial anomalies and head magnetic resonance imaging indicated semilobar HPE. After birth, she had hyponatremia due to SIADH and was treated using water and sodium restriction. However, she developed an exaggerated response to the fluid restrictions, resulting in large fluctuations in serum sodium levels. Subsequent administration of tolvaptan improved the fluctuations in serum sodium levels without the need for adjustment of water or sodium administration. Serum sodium was maintained within the normal range after discontinuation of tolvaptan at 80 d of life. There were no side effects, such as hypernatremia or liver dysfunction, during the administration of tolvaptan. CONCLUSION: This is the first report on the safety and efficacy of tolvaptan in an infant with SIADH associated with HPE.

5.
Angew Chem Int Ed Engl ; 62(41): e202306518, 2023 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-37466360

RESUMO

A new series of transparent aerogels of biopolymer-polysiloxane double networks is reported. Biopolymer aerogels have attracted much attention from green and sustainable aspects but suffered from strong hydrophilicity and difficulty to make homogeneous structures in nanoscale; these drawbacks are overcome by compositing with a polysiloxane network. Alginate-polymethylsilsesquioxane aerogel has high optical transparency, water repellency, comparable superinsulation property and improved bending flexibility compared to pure polymethylsilsesquioxane aerogel. The nanoscale homogeneity is realized by separating the crosslinking steps for two networks in a sequential protocol: condensation of siloxane bonds and metal-crosslinking of biopolymer. The crosslinking order, biopolymer-first or siloxane-first, and universality/limitation of biopolymer-crosslinker pairs are discussed to construct fundamental chemistry of double network systems for their further application potentials.

6.
Am J Case Rep ; 24: e939642, 2023 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-37357428

RESUMO

BACKGROUND Choanal atresia with a supernumerary nostril located on the columella is extremely rare. Infants are obligate nasal breathers because the oral airway is invariably blocked during calm respiration. Infants breathe through the mouth only during crying, and they only have nasal breathing until 5 months of life. Congenital nasal anomalies have been reported to be fatal from birth, requiring tracheal intubation or tracheostomy in the early postnatal period. In these cases, it is crucial to maintain an adequate airway. CASE REPORT A 2948-g female infant was born at 40 weeks by normal vaginal delivery. Her Apgar scores were 9 and 9 at 1 and 5 min, respectively. She had retractive breathing, cyanosis, and a supernumerary nostril at birth. She had no other anomalies. Computed tomography showed bilateral membranous choanal atresia. She needed nasal continuous positive pressure or a high-flow nasal canula for oxygen desaturation during crying, apnea, and dyspnea. However, her respiratory symptoms did not improve completely. On day 25 of life, she was given a mouthpiece to support mouth breathing. Her respiratory symptoms improved gradually, and she was discharged on day 73 of life with a mouthpiece. CONCLUSIONS A very rare case of choanal atresia with a supernumerary nostril located on the columella was described. A mouthpiece was effective for breathing, obviating the need for emergency surgical intervention in the early postnatal period. Emergency procedures were avoided, probably because this case involved incomplete bilateral membranous choanal atresia rather than complete bony atresia.


Assuntos
Atresia das Cóanas , Recém-Nascido , Humanos , Lactente , Feminino , Atresia das Cóanas/cirurgia , Atresia das Cóanas/diagnóstico , Septo Nasal , Dispneia , Tomografia Computadorizada por Raios X , Traqueostomia
7.
Curr Cancer Drug Targets ; 23(11): 837-842, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37221685

RESUMO

BACKGROUND: Neuroblastoma is one of the most common childhood solid tumors. Because tumor suppressor genes are often hypermethylated in cancers, DNA methylation has emerged as a target for cancer therapeutics. Nanaomycin A, an inhibitor of DNA methyltransferase 3B, which mediates de novo DNA methylation, reportedly induces death in several types of human cancer cells. OBJECTIVE: To study the antitumor activity of nanaomycin A against neuroblastoma cell lines and its mechanism. METHODS: The anti-tumor effect of nanaomycin A on neuroblastoma cell lines was evaluated based on cell viability, DNA methylation levels, apoptosis-related protein expression, and neuronal-associated mRNA expression. RESULTS: Nanaomycin A decreased genomic DNA methylation levels and induced apoptosis in human neuroblastoma cells. Nanaomycin A also upregulated the expression of mRNAs for several genes related to neuronal maturation. CONCLUSIONS: Nanaomycin A is an effective therapeutic candidate for treating neuroblastoma. Our findings also suggest that the inhibition of DNA methylation is a promising anti-tumor therapy strategy for neuroblastoma.


Assuntos
Naftoquinonas , Neuroblastoma , Humanos , Criança , Neuroblastoma/tratamento farmacológico , Neuroblastoma/genética , Neuroblastoma/metabolismo , DNA (Citosina-5-)-Metiltransferases/metabolismo , Naftoquinonas/farmacologia , Naftoquinonas/uso terapêutico , Metilação de DNA , Linhagem Celular Tumoral , DNA Metiltransferase 3B
8.
Int J Mol Sci ; 24(3)2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36769149

RESUMO

Atherosclerosis can lead to cardiovascular and cerebrovascular diseases. Atherosclerotic plaque formation is promoted by the accumulation of inflammatory cells. Therefore, modulating monocyte recruitment represents a potential therapeutic strategy. In an inflammatory state, the expression of adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) is upregulated in endothelial cells. We previously reported that miR-1914-5p in endothelial cells suppresses interleukin (IL)-1ß-induced ICAM-1 expression and monocyte adhesion to endothelial cells. However, whether monocyte miR-1914-5p affects monocyte recruitment is unclear. In this study, IL-1ß decreased miR-1914-5p expression in a human monocyte cell line. Moreover, miR-1914-5p inhibition enhanced adhesion to endothelial cells with the upregulation of macrophage-1 antigen (Mac-1), a counter-ligand to ICAM-1. Transmigration through the endothelial layer was also promoted with the upregulation of monocyte chemotactic protein-1 (MCP-1). Furthermore, a miR-1914-5p mimic suppressed IL-1ß-induced monocyte adhesion and transmigration in monocytes with Mac-1 and MCP-1 downregulation. Further investigation of miR-1914-5p in monocytes could lead to the development of novel diagnostic markers and therapeutic strategies for atherosclerosis.


Assuntos
Aterosclerose , MicroRNAs , Humanos , Monócitos/metabolismo , Molécula 1 de Adesão Intercelular/genética , Molécula 1 de Adesão Intercelular/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Células Endoteliais/metabolismo , Aterosclerose/genética , Aterosclerose/metabolismo , Adesão Celular/fisiologia
9.
Pediatr Res ; 93(3): 619-624, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-35568734

RESUMO

BACKGROUND: Small-for-gestational-age (SGA) infants are at increased risk for transient thrombocytopenia. The aim of this study was to determine whether thrombocytopenia in human SGA infants is due to insufficient thrombopoietin (TPO) production. METHODS: A prospective study of 202 infants with gestational age less than 37 weeks was conducted; 30 of them were SGA infants, and 172 were non-SGA infants. Thrombocytopenia was seen in 17 of 30 SGA infants and 40 of 172 non-SGA infants. RESULTS: Platelet counts were significantly lower in the SGA group than in the non-SGA group at the time of the lowest platelet count within 72 h of birth. The platelet count and immature platelet fraction (IPF) were negatively correlated in non-SGA infants, but not in SGA infants. In addition, the platelet count and TPO were negatively correlated in non-SGA infants. IPF and TPO were significantly lower in SGA than in non-SGA infants with thrombocytopenia. CONCLUSION: IPF increased with thrombocytopenia to promote platelet production in non-SGA infants due to increasing TPO, but not in SGA infants. This study found an association between insufficient TPO production and thrombocytopenia in SGA infants. In addition, this study is important for understanding the etiology of thrombocytopenia in SGA infants. IMPACT: The immature platelet fraction was low, and serum thrombopoietin was not increased in small-for-gestational-age (SGA) infants with thrombocytopenia. Thrombocytopenia in SGA infants is due to insufficient thrombopoietin production. This study is important for understanding the etiology of thrombocytopenia in SGA infants.


Assuntos
Trombocitopenia , Trombopoetina , Feminino , Humanos , Lactente , Estudos Prospectivos , Contagem de Plaquetas , Plaquetas , Retardo do Crescimento Fetal
10.
Neonatology ; 119(6): 781-784, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36183690

RESUMO

The use of linezolid is relatively safe for all age categories, including premature infants. The case of an extremely premature infant with hyperglycemia and lactic acidosis associated with linezolid is reported. A 350-g male infant was born at 24 weeks by cesarean section. His Apgar scores were 1 and 1 at 1 and 5 min, respectively. On the day of life (DOL) 7, linezolid was started at a dose of 10 mg/kg/dose every 8 h for a catheter-related blood stream infection caused by methicillin-resistant coagulase-negative Staphylococci. After linezolid was given, serum lactate and glucose levels increased gradually. After discontinuation of linezolid on DOL 16, hyperglycemia and lactic acidosis improved immediately. In conclusion, a rare case of an extremely premature infant with hyperglycemia and lactic acidosis associated with linezolid was reported. It is crucial to monitor glucose levels along with lactate and pH levels during linezolid therapy.


Assuntos
Acidose Láctica , Feminino , Gravidez , Masculino , Humanos , Recém-Nascido , Acidose Láctica/induzido quimicamente , Linezolida/efeitos adversos , Lactente Extremamente Prematuro , Cesárea , Ácido Láctico , Glucose
11.
Pediatr Int ; 64(1): e14747, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33904213

RESUMO

BACKGROUND: Antenatal magnesium sulfate (MgSO4 ) has been used with mothers, but the influence of MgSO4 on the fetus is unclear. The purpose of this study is to determine whether longer antenatal MgSO4 exposure correlates with adverse effects in newborns. METHODS: The clinical data of 77 infants born to mothers treated with MgSO4 were collected. The infants were divided into two groups according to (1) the serum Mg concentration, (2) cumulative Mg dose, and (3) duration of antenatal maternal Mg treatment, respectively. RESULTS: The serum Mg level of the infants correlated with that of the mothers but not with the duration of Mg treatment or the cumulative dose of Mg. There were no significant differences in the infants' clinical variables according to either the duration of Mg treatment or the cumulative dose of Mg. By contrast, enteral feeding tolerance began at a significantly later age and the heart rate on admission was significantly lower in infants with a serum Mg level ≥4.0 mmol/L than in those with a serum Mg level <4.0 mmol/L. CONCLUSIONS: Modest effects on the clinical variables of infants with higher serum Mg levels were determined, whereas neither the duration of Mg treatment nor the cumulative Mg dose correlated with the clinical variables of the infants. Thus, in newborns with only moderately elevated serum Mg levels, serious adverse effects are unlikely.


Assuntos
Sulfato de Magnésio , Pré-Eclâmpsia , Feminino , Feto , Humanos , Recém-Nascido , Sulfato de Magnésio/efeitos adversos , Gravidez
12.
Pediatr Int ; 63(9): 1069-1074, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33464662

RESUMO

BACKGROUND: Acetaminophen is widely administered to neonates but its effect on unbound bilirubin (UB) levels remains unclear. The aim of this study was to clarify whether administration of acetaminophen is related to an elevation of UB levels. METHOD: Infants with a birthweight of ˂1,500 g admitted to our neonatal intensive care unit between January 2017 and April 2020 were retrospectively reviewed. Seventy-one infants were enrolled, five of whom had received acetaminophen. Clinical data were analyzed when the highest UB value (UB peak) in each infant was recorded. Demographic data and information on treatment within the 24 h before the UB peak were also collected. UB was determined by the glucose oxidase-peroxidase (GOD-POD) method. Infants were categorized according to the presence or absence of acetaminophen administration (acetaminophen and no acetaminophen groups) within 24 h of the UB peak. The relationship between UB values and various clinical variables was then compared. RESULTS: Both the peak UB value and the ratio of gastrointestinal disease were higher in the acetaminophen group than in the no acetaminophen group. Univariate analysis revealed that a total of seven variables were potentially correlated with UB peak values (P < 0.10). Multivariate analysis showed that acetaminophen and direct bilirubin were independently associated with UB peak values. CONCLUSION: Our study suggests that administration of acetaminophen is related to higher UB levels by the GOD-POD method. UB values measured by the GOD-POD method should not be used in infants treated with acetaminophen for evaluation of bilirubin neurotoxicity avoidance.


Assuntos
Icterícia Neonatal , Peroxidase , Acetaminofen/efeitos adversos , Bilirrubina , Glucose Oxidase , Humanos , Lactente , Recém-Nascido , Oxirredutases , Peroxidases , Estudos Retrospectivos
14.
Angew Chem Int Ed Engl ; 60(18): 9828-9851, 2021 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-32270894

RESUMO

Chitosan is an abundant biopolymer derived from food waste with attractive properties, particularly its high biocompatibility and easy chemical processability. Here, we review the rapidly expanding literature on chitosan-based porous materials with a focus on the gelation mechanisms, the three-dimensional multiscale structural control, and the diverse chemical functionality not accessible by other biopolymers. The properties vary widely: from supercritically dried, mesoporous chitosan aerogels to very light, freeze-dried macroporous scaffolds. Porous chitosan displays impressive performance at the laboratory scale, but the highly (meso)porous nature amplifies not only the beneficial functionality of chitosan, but also its drawbacks, resulting in serious barriers to industrialization. In order to facilitate technology transfer, we critically discuss the practical feasibility of chitosan aerogels in potential applications compared to conventional and other biopolymer-based porous or nonporous materials.

15.
Cell Mol Neurobiol ; 41(3): 459-468, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32382852

RESUMO

Although therapeutic hypothermia (TH) provides neuroprotection, the cellular mechanism underlying the neuroprotective effect of TH has not yet been fully elucidated. In the present study, we investigated the effect of TH on microglial activation to determine whether hypothermia attenuates neuronal damage via microglial activation. After lipopolysaccharide (LPS) stimulation, BV-2 microglia cells were cultured under normothermic (37 °C) or hypothermic (33.5 °C) conditions. Under hypothermic conditions, expression of pro-inflammatory cytokines and inducible nitric oxide synthase (iNOS) was suppressed. In addition, phagocytosis of latex beads was significantly suppressed in BV-2 cells under hypothermic conditions. Moreover, nuclear factor-κB signaling was inhibited under hypothermic conditions. Finally, neuronal damage was attenuated following LPS stimulation in neurons co-cultured with BV-2 cells under hypothermic conditions. In conclusion, hypothermia attenuates neuronal damage via inhibition of microglial activation, including microglial iNOS and pro-inflammatory cytokine expression and phagocytic activity. Investigating the mechanism of microglial activation regulation under hypothermic conditions could contribute to the development of novel neuroprotective therapies.


Assuntos
Citocinas/biossíntese , Hipotermia/patologia , Microglia/patologia , Neurônios/patologia , Fagocitose , Animais , Linhagem Celular , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Citocinas/genética , Regulação da Expressão Gênica , Mediadores da Inflamação/metabolismo , Interleucina-1beta/genética , Interleucina-1beta/metabolismo , Lipopolissacarídeos , Camundongos Endogâmicos C57BL , NF-kappa B/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Transdução de Sinais/efeitos dos fármacos , Fator de Necrose Tumoral alfa/metabolismo
16.
Carbohydr Polym ; 251: 117089, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33142630

RESUMO

Aldehyde-free, transparent chitosan aerogel is reported. The aerogel was prepared by thermal decomposition of urea to induce gelation of a chitosan solution, followed by solvent exchange to ethanol, and supercritical drying. Low urea concentrations (≤ 25 g L-1) result in transparent and highly mesoporous aerogels, while higher urea concentrations (≥ 30 g L-1) produce opaque, more macroporous aerogels. The high surface areas of > 400 m2 g-1, large mesopore volumes up to 3.5 cm3 g-1, and optical transparency of the low-urea aerogels indicate a high structural homogeneity at the mesoscale, and the properties comparable to previously reported transparent chitosan aerogels prepared with formaldehyde crosslinking. The macroscopic size changes of the wet gels indicate that microstructure formation is controlled by the timing of chitosan coagulation, which depends among others on urea concentration. The aldehyde-free, microstructure-tunable process provides a new series of transparent biopolymer aerogels with "true aerogel" mesoporous structures.

17.
Carbohydr Polym ; 247: 116680, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32829808

RESUMO

The functionality of biopolymer aerogels is inherently linked to its microstructure, which in turn depends on the synthesis protocol. Detailed investigations on the macroscopic size change and nanostructure formation during chitosan aerogel synthesis reveal a new aspect of biopolymer aerogels that increases process flexibility. Formaldehyde-cross-linked chitosan gels retain a significant fraction of their original volume after solvent exchange into methanol (50.3 %), ethanol (47.1 %) or isopropanol (26.7 %), but shrink dramatically during subsequent supercritical CO2 processing (down to 4.9 %, 3.5 % and 3.7 %, respectively). In contrast, chitosan gels shrink more strongly upon exchange into n-heptane (7.2 %), a low affinity solvent, and retain this volume during CO2 processing. Small-angle X-ray scattering confirms that the occurrence of the volumetric changes correlates with mesoporous network formation through physical coagulation in CO2 or n-heptane. The structure formation step can be controlled by solvent-polymer and polymer-drying interactions, which would be a new tool to tailor the aerogel structure.


Assuntos
Biopolímeros/química , Dióxido de Carbono/química , Quitosana/química , Hidrogéis/química , Solventes/química , 2-Propanol/química , Adsorção , Biopolímeros/análise , Dessecação/métodos , Etanol/química , Formaldeído/química , Heptanos/química , Metanol/química , Microscopia Eletrônica de Varredura , Nanoestruturas/química , Nitrogênio/química , Tamanho da Partícula , Porosidade , Espalhamento a Baixo Ângulo , Fatores de Tempo
18.
J Neuroinflammation ; 17(1): 141, 2020 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-32359362

RESUMO

BACKGROUND: Hypoxic-ischemic encephalopathy (HIE) has a high morbidity rate and involves severe neurologic deficits, including cerebral palsy. Therapeutic hypothermia (TH) has been shown to decrease the mortality rate and provide neuroprotection in infants with HIE. However, death and disability rates in HIE infants treated with TH remain high. Although the cellular mechanism of the neuroprotective effect of TH remains unclear, astrocytic erythropoietin (EPO) is known to be a key mediator of neuroprotection under hypoxic conditions. In the present study, we investigated the hypothermia effect on EPO expression in astrocytes and determined whether hypothermia attenuates neuronal damage via EPO signaling. METHODS: Astrocytes derived from rat cerebral cortex were cultured under oxygen/glucose deprivation (OGD). The expression of EPO and hypoxia-inducible factor (HIF), a transcription factor of EPO, was assessed. After OGD, astrocytes were cultured under normothermic (37 °C) or hypothermic (33.5 °C) conditions, and then EPO and HIF expression was assessed. After OGD, rat cortical neurons were cultured in astrocyte-conditioned medium (ACM) derived from the hypothermic group, and neuronal apoptosis was evaluated. RESULTS: OGD induced EPO mRNA and protein expression, although at lower levels than hypoxia alone. HIF-1α and HIF-2α protein expression increased under hypoxia alone and OGD, although OGD increased HIF-2α protein expression less than hypoxia alone. EPO gene and protein expression after OGD was significantly higher under hypothermia. Moreover, expression of HIF-1α and HIF-2α protein was enhanced under hypothermia. In the presence of ACM derived from hypothermic astrocytes following OGD, the number of cleaved caspase 3 and TdT-mediated dUTP nick-end labeling-positive apoptotic neurons was lower than in the presence of ACM from normothermic astrocytes following OGD. Blockade of EPO signaling using anti-EPO neutralization antibody attenuated the anti-apoptotic effect of ACM derived from hypothermic astrocytes following OGD. CONCLUSIONS: Hypothermia after OGD stabilized HIF-EPO signaling in astrocytes, and upregulated EPO expression could suppress neuronal apoptosis. Investigating the neuroprotective effect of EPO from astrocytes under hypothermic conditions may contribute to the development of novel neuroprotection-based therapies for HIE.


Assuntos
Astrócitos/metabolismo , Eritropoetina/biossíntese , Hipotermia Induzida , Neurônios/patologia , Neuroproteção/fisiologia , Animais , Hipóxia-Isquemia Encefálica/patologia , Ratos , Ratos Wistar
19.
Neonatology ; 116(4): 376-379, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31553974

RESUMO

BACKGROUND: Food protein-induced enterocolitis syndrome (FPIES) is a non-IgE-mediated food allergy. The pathological mechanism of FPIES is intestinal inflammation, and cell-mediated hypersensitivity is presumed to play an important role in its development. CASE REPORT: The first case in which significant fetal intestinal distension suggested fetal onset of FPIES is reported. A 2,334-g male was born at 34 weeks by vaginal delivery. RESULTS: In utero, he had significant intestinal distension on ultrasonography and MRI. A few hours after the first feeding, he produced bloody stool and showed abdominal distension. In this case, FPIES was not only caused by cow's milk protein diagnosed clinically and by an allergen-specific lymphocyte stimulation test, but also by breast milk diagnosed by oral food challenge. The clinical course and laboratory results strongly suggested not only fetal sensitization but also fetal onset. CONCLUSION: This report might be helpful for prompt diagnosis and treatment and, furthermore, lead to elucidation of the pathogenesis and pathophysiology of FPIES.


Assuntos
Enterocolite/etiologia , Doenças Fetais/diagnóstico por imagem , Hipersensibilidade Alimentar/complicações , Proteínas do Leite/efeitos adversos , Líquido Amniótico/química , Animais , Bovinos , Enterocolite/fisiopatologia , Hipersensibilidade Alimentar/fisiopatologia , Humanos , Lactente , Recém-Nascido Prematuro , Imageamento por Ressonância Magnética , Masculino , Proteínas do Leite/imunologia , Síndrome , Ultrassonografia Pré-Natal
20.
Pediatr Int ; 61(11): 1114-1119, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31281996

RESUMO

BACKGROUND: Late-onset circulatory collapse (LCC) is the transient development of refractory hypotension and oliguria after the early neonatal period, which may cause periventricular leukomalacia (PVL). The aim of this study was to evaluate the endogenous cortisol response to corticotrophin-releasing hormone (CRH) and determine whether it is effective for elucidating the pathology and selecting treatment in LCC. METHODS: This retrospective study examined infants admitted to the neonatal intensive care unit. Included were preterm (gestational age <34 weeks) infants who underwent CRH stimulation test and were treated for LCC with no obvious cause. Hydrocortisone (HC; 3.3-10 mg/kg) was given by bolus injection to the LCC infants. At 2 h after treatment, infants without a 20% rise in blood pressure (systolic or mean) from before treatment were defined as non-responsive to HC, and given catecholamine and/or vasopressin. RESULTS: Sixteen infants (median gestational age, 24 weeks 3 days; birthweight, 638 g) were eligible. Six of the infants had a good response to the CRH stimulation test. HC was effective in only three CRH good-response cases, and catecholamine and/or vasopressin was needed in the three other cases. HC was effective, however, for all CRH non-response cases. CONCLUSIONS: Although HC is the first-choice treatment for LCC, the CRH stimulation test facilitates prompt treatment of LCC, which may prevent PVL. The present findings help elucidate the pathology and aid in the selection of treatment for infants with LCC.


Assuntos
Hormônio Liberador da Corticotropina/efeitos dos fármacos , Hidrocortisona/administração & dosagem , Recém-Nascido Prematuro , Choque/tratamento farmacológico , Pressão Sanguínea/efeitos dos fármacos , Hormônio Liberador da Corticotropina/metabolismo , Feminino , Idade Gestacional , Glucocorticoides/administração & dosagem , Humanos , Recém-Nascido , Unidades de Terapia Intensiva Neonatal , Masculino , Prognóstico , Estudos Retrospectivos , Choque/diagnóstico , Choque/metabolismo
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