RESUMO
L-Fucose (6-deoxy-L-galactose), a monosaccharide abundant in glycolipids and glycoproteins produced by mammalian cells, has been extensively studied for its role in intracellular biosynthesis and recycling of GDP-L-fucose for fucosylation. However, in certain mammalian species, L-fucose is efficiently broken down to pyruvate and lactate in a poorly understood metabolic pathway. In the 1970s, L-fucose dehydrogenase, an enzyme responsible for the initial step of this pathway, was partially purified from pig and rabbit livers and characterized biochemically. However, its molecular identity remained elusive until recently. This study reports the purification, identification, and biochemical characterization of the mammalian L-fucose dehydrogenase. The enzyme was purified from rabbit liver approximately 340-fold. Mass spectrometry analysis of the purified protein preparation identified mammalian hydroxysteroid 17-ß dehydrogenase 14 (HSD17B14) as the sole candidate enzyme. Rabbit and human HSD17B14 were expressed in HEK293T and Escherichia coli, respectively, purified, and demonstrated to catalyze the oxidation of L-fucose to L-fucono-1,5-lactone, as confirmed by mass spectrometry and NMR analysis. Substrate specificity studies revealed that L-fucose is the preferred substrate for both enzymes. The human enzyme exhibited a catalytic efficiency for L-fucose that was 359-fold higher than its efficiency for estradiol. Additionally, recombinant rat HSD17B14 exhibited negligible activity towards L-fucose, consistent with the absence of L-fucose metabolism in this species. The identification of the gene-encoding mammalian L-fucose dehydrogenase provides novel insights into the substrate specificity of enzymes belonging to the 17-ß-hydroxysteroid dehydrogenase family. This discovery also paves the way for unraveling the physiological functions of the L-fucose degradation pathway, which remains enigmatic.
RESUMO
Iron is the micronutrient with the best-studied biological functions. It is widely distributed in nature, and its involvement in the main metabolic pathways determines the great importance of this metal for all organisms. Iron is required for cellular respiration and various biochemical processes that ensure the proper functioning of cells and organs in the human body, including the brain. Iron also plays an important role in the production of free radicals, which can be beneficial or harmful to cells under various conditions. Reviews of iron metabolism and its regulation can be found in the literature, and further advances in understanding the molecular basis of iron metabolism are being made every year. The aim of this review is to systematise the available data on the role of iron in the function of the nervous system, especially in the brain. The review summarises recent views on iron metabolism and its regulatory mechanisms in humans, including the essential action of hepcidin. Special attention is given to the mechanisms of iron absorption in the small intestine and the purpose of this small but critically important pool of iron in the brain.
RESUMO
L-2-Keto-3-deoxyfuconate 4-dehydrogenase (L-KDFDH) catalyzes the NAD+-dependent oxidization of L-2-keto-3-deoxyfuconate (L-KDF) to L-2,4-diketo-3-deoxyfuconate (L-2,4-DKDF) in the non-phosphorylating L-fucose pathway from bacteria, and its substrate was previously considered to be the acyclic α-keto form of L-KDF. On the other hand, BDH2, a mammalian homolog with L-KDFDH, functions as a dehydrogenase for cis-4-hydroxy-L-proline (C4LHyp) with the cyclic structure. We found that L-KDFDH and BDH2 utilize C4LHyp and L-KDF, respectively. Therefore, to elucidate unique substrate specificity at the atomic level, we herein investigated for the first time the crystal structures of L-KDFDH from Herbaspirillum huttiense in the ligand-free, L-KDF and L-2,4-DKDF, D-KDP (D-2-keto-3-deoxypentonate; additional substrate), or L-2,4-DKDF and NADH bound forms. In complexed structures, L-KDF, L-2,4-DKDF, and D-KDP commonly bound as a α-furanosyl hemiketal. Furthermore, L-KDFDH showed no activity for L-KDF and D-KDP analogs without the C5 hydroxyl group, which form only the acyclic α-keto form. The C1 carboxyl and α-anomeric C2 hydroxyl groups and O5 oxygen atom of the substrate (and product) were specifically recognized by Arg148, Arg192, and Arg214. The side chain of Trp252 was important for hydrophobically recognizing the C6 methyl group of L-KDF. This is the first example showing the physiological role of the hemiketal of 2-keto-3-deoxysugar acid.
Assuntos
Modelos Moleculares , Especificidade por Substrato , Cristalografia por Raios X , Ligação Proteica , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Sítios de LigaçãoRESUMO
Background: Kidneys play an essential role in the circulatory system, regulating blood pressure and intravascular volume. They are also set on maintaining an adequate filtration pressure in the glomerulus. During the CPB, a decrease in systemic blood pressure and hemoglobin concentration may lead to renal ischemia and subsequent acute kidney injury. Methods: One hundred nine adult patients were prospectively enrolled in this study. The intervention in this study was increasing the flow of the CPB pump to reach the target MAP of > 90 mmHg during the procedure. The control group had a standard pump flow of 2.4 L/min/m2. Results: Standard pump flow of 2.4 L/min/m2 resulted in mean MAP < 90 mmHg during the CPB in most patients in the control group. Maintaining a higher MAP during CPB in this study population did not affect CSA-AKI incidence. However, it increased the intraoperative and postoperative diuresis and decreased renin release associated with CPB. Higher MAP during the CPB did not increase the incidence of cerebrovascular complications after the operation; patients in the highest MAP group had the lowest incidence of postoperative delirium, but the result did not obtain statistical significance. Conclusion: Maintaining MAP > 90 mmHg during the CPB positively impacts intraoperative and postoperative kidney function. It significantly reduces renal hypoperfusion during the procedure compared to MAP < 70 mmHg. MAP > 90 mmHg is safe for the central nervous system, and preliminary results suggest that it may have a beneficial impact on the incidence of postoperative delirium.
RESUMO
INTRODUCTION: Physical activity during pregnancy is established to derive clinically meaningful improvements in pregnancy, childbirth, and postpartum health outcomes. Evidence-based pre-screening tools have been developed to support the implementation of physical activity programmes, and enhance communication between health care providers, exercise professionals and pregnant women. The Get Active Questionnaire for Pregnancy (GAQ-P) and the Health Care Provider Consultation Form for Prenatal Physical Activity (HCPCF) empower pregnant women to identify whether they require additional counselling from their obstetric health care provider in terms of physical activity. However, these tools are not available in Polish. This work details the process taken to translate the GAQ-P and HCPCF into Polish. MATERIAL AND METHODS: We followed the translation process outlined by the Translation and Cultural Adaptation International Society for Pharmacoeconomics and Outcomes Research (ISPOR) guidelines between August 2022 and August 2023. We formed an expert group that included representatives of the Polish Society of Sports Medicine, The Polish Society of Gynaecologists and Obstetricians, practitioners, and scientists in physical activity during pregnancy. We implemented 9 of the 10 steps recommended by ISOPR in the translation process. At the Cognitive Debriefing stage, we collected opinions on the Polish version of GAQ-P and HCPCF from 70 stakeholders on the clarity and cultural appropriateness of the translation. RESULTS AND CONCLUSIONS: Target users have positively evaluated the Polish version of GAQ-P and HCPCF. Thanks to the ISPOR methodology, we obtained a trustworthy, evidence-based screening tools, which can reduce the barriers for most women to be physically active during pregnancy.
RESUMO
OBJECTIVES: The Polish criteria for "intrauterine death" include fetal demise after 22 weeks of gestation, weighing > 500 g and body length at least 25 cm, when the gestational age is unknown. The rate of fetal death in Poland in 2015 is 3:10,000. In 2020, 1,231 stillbirths were registered. MATERIAL AND METHODS: An analysis using 142,662 births in the period between 2015-2020 in 11 living in Poland. The first subgroup was admitted as patients > 22 to the beginning of the 30th week of pregnancy (n = 229), and the second from the 30th week of pregnancy inclusively (n = 179). In the case of women from both subgroups, there was a risk of preterm delivery close to hospitalization. RESULTS: It was found that stillbirth in 41% of women in the first pregnancy. For the patient, stillbirth was also the first in his life. The average stillbirth weight was 1487 g, the average body length was 40 cm. Among fetuses up to 30 weeks, male fetuses are born more often, in subgroup II, the sex of the child was usually female. Most fetal deaths occur in mothers < 15 and > 45 years of age. CONCLUSIONS: According to the Polish results of the origin of full-term fetuses > 30 weeks of gestation for death in the concomitant antenatal, such as placental-umbilical and fetal hypoxia, acute intrapartum effects rarely, and moreover < 30 Hbd fetal growth restriction (FGR), occurring placental-umbilical, acute intrapartum often.