Mass spectrometry imaging-based assays for aminotransferase activity reveal a broad substrate spectrum for a previously uncharacterized enzyme.

Aminotransferases (ATs) catalyze pyridoxal 5'-phosphate-dependent transamination reactions between amino donor and keto acceptor substrates and play central roles in nitrogen metabolism of all organisms. ATs are involved in the biosynthesis and degradation of both proteinogenic and nonproteinogenic amino acids and also carry out a wide variety of functions in photorespiration, detoxification, and secondary metabolism. Despite the importance of ATs, their functionality is poorly understood as only a small fraction of putative ATs, predicted from DNA sequences, are associated with experimental data. Even for characterized ATs, the full spectrum of substrate specificity, among many potential substrates, has not been explored in most cases. This is largely due to the lack of suitable high-throughput assays that can screen for AT activity and specificity at scale. Here we present a new high-throughput platform for screening AT activity using bioconjugate chemistry and mass spectrometry imaging-based analysis. Detection of AT reaction products is achieved by forming an oxime linkage between the ketone groups of transaminated amino donors and a probe molecule that facilitates mass spectrometry-based analysis using nanostructure-initiator mass spectrometry or MALDI-mass spectrometry. As a proof-of-principle, we applied the newly established method and found that a previously uncharacterized Arabidopsis thaliana tryptophan AT-related protein 1 is a highly promiscuous enzyme that can utilize 13 amino acid donors and three keto acid acceptors. These results demonstrate that this oxime-mass spectrometry imaging AT assay enables high-throughput discovery and comprehensive characterization of AT enzymes, leading to an accurate understanding of the nitrogen metabolic network.

Pentadecanoic Acid Supplementation in Young Adults with Overweight and Obesity: A Randomized Controlled Trial.

BACKGROUND: Obesity and its associated comorbidities are major public health concerns for which nutrition is central to disease prevention and management. Pentadecanoic acid (C15:0) has the potential for beneficial effects on obesity, but supplementation has not been studied in humans. OBJECTIVES: The primary objective was to investigate changes in plasma C15:0 levels after daily supplementation for 12 wk. Additionally, the study aimed to assess safety and tolerability as well as measure potential markers of physiologic response. METHODS: This was a single-center, double-blind, randomized, controlled, 2-arm trial of 200 mg C15:0 or placebo daily for 12 wk in young adults with overweight or obesity. RESULTS: A total of 30 participants with a mean age of 20.0 ± 2.1 y and a mean body mass index of 33.4 ± 5.3 kg/m2 were included. In total, 20 participants received C15:0 supplement and 10 received placebo. The mean increase in circulating C15:0 for the treatment group was 1.88 µg/mL greater than that of the placebo group (P = 0.003). No significant adverse events occurred. Half of the participants in the treatment group had a posttreatment C15:0 level >5 µg/mL. In these individuals, there were significantly greater decreases in alanine aminotransferase (-29 U/L, P = 0.001) and aspartate aminotransferase (-6 U/L, P = 0.014), as well as a greater increase in hemoglobin (0.60 g/dL, P = 0.010), as compared with participants that did not reach a posttreatment level >5 µg/mL. CONCLUSIONS: Daily C15:0 supplementation increased circulating C15:0 levels in young adults with overweight or obesity. End-of-treatment C15:0 >5 µg/mL was associated with potentially relevant improvements in clinical indices, warranting further study. This trial was registered at clinicaltrials.gov as NCT04947176.

Impact of gastrointestinal inoculation and benznidazole treatment on infection by Trypanosoma cruzi (Y strain, DTU TcII) in Swiss mice.

In Brazil, where Chagas disease is endemic, the most frequent form of transmission of the parasite is the oral route, associated with greater severity and worse response to benznidazole (BZ), the drug used in its treatment. This study aimed to evaluate the impact of gastrointestinal infection (GI) and BZ treatment on the parasitological and histopathological parameters in mice inoculated with a strain of T. cruzi II. Swiss mice were inoculated by GI and intraperitoneal (IP) routes with 2x106 culture-derived metacyclic trypomastigotes of the Y strain (TcII) of T. cruzi and were treated with BZ in the acute phase of the infection. Fresh blood examination, qPCR, histopathological and biochemical evaluations (enzymatic dosages and oxidative stress-OS) were performed. BZ treatment of uninfected animals caused changes in the liver, increased the activity of aspartate aminotransferase and alanine aminotransferase enzymes and OS, showing that the drug alone affects this organ. Inflammation and necrosis in the cardiac tissue were less intense and deaths occurred later in animals inoculated via the GI route than the animals inoculated via the IP route. BZ reduced the intensity of tissue lesions and avoided lethality in animals inoculated via the GI route, and decreased parasitemia and OS in those inoculated via both routes. Although BZ alone caused liver damage, it was less intense than that caused by both routes of inoculation. Infection with the Y strain of T. cruzi II via the GI route proved to be less virulent and pathogenic and responded better to treatment than the infection acquired via the IP route.

Does curcumin improve liver enzymes levels in nonalcoholic fatty liver disease? A systematic review, meta-analysis, and meta-regression.

The aim of this meta-analysis is to investigate the sources of heterogeneity in randomized clinical trials examining the effects of curcumin supplementation on liver aminotransferases in subjects with nonalcoholic fatty liver disease (NAFLD). We conducted a systematic search of the PubMed, SCOPUS, and Web of Science databases for randomized clinical trials and identified 15 studies (n = 835 subjects). We used random-effects models with DerSimonian-Laird methods to analyze the serum levels of alanine aminotransferase and aspartate aminotransferase enzymes. Our results indicate that curcumin did not affect serum alanine aminotransferase, but it did reduce aspartate aminotransferase levels. Notably, both outcomes showed high heterogeneity (p < 0.01). Subgroup analysis revealed that adding piperine to curcumin did not benefit aminotransferase levels in NAFLD patients. Additionally, we found a negative correlation between the duration of the intervention and the relative (mg/kg/day) curcumin dose with the reduction in liver aminotransferases. In summary, the sources of heterogeneity identified in our study are likely attributed to the duration of the intervention and the relative dose of curcumin. Consequently, longer trials utilizing high doses of curcumin could diminish the positive impact of curcumin in reducing serum levels of aminotransferases in patients with NAFLD.

The Probiotic Lactobacillus reuteri Preferentially Synthesizes Kynurenic Acid from Kynurenine.

The gut-brain axis is increasingly understood to play a role in neuropsychiatric disorders. The probiotic bacterium Lactobacillus (L.) reuteri and products of tryptophan degradation, specifically the neuroactive kynurenine pathway (KP) metabolite kynurenic acid (KYNA), have received special attention in this context. We, therefore, assessed relevant features of KP metabolism, namely, the cellular uptake of the pivotal metabolite kynurenine and its conversion to its primary products KYNA, 3-hydroxykynurenine and anthranilic acid in L. reuteri by incubating the bacteria in Hank's Balanced Salt solution in vitro. Kynurenine readily entered the bacterial cells and was preferentially converted to KYNA, which was promptly released into the extracellular milieu. De novo production of KYNA increased linearly with increasing concentrations of kynurenine (up to 1 mM) and bacteria (107 to 109 CFU/mL) and with incubation time (1-3 h). KYNA neosynthesis was blocked by two selective inhibitors of mammalian kynurenine aminotransferase II (PF-048559989 and BFF-122). In contrast to mammals, however, kynurenine uptake was not influenced by other substrates of the mammalian large neutral amino acid transporter, and KYNA production was not affected by the presumed competitive enzyme substrates (glutamine and α-aminoadipate). Taken together, these results reveal substantive qualitative differences between bacterial and mammalian KP metabolism.

Evaluating treatment effect on interferon-alpha in female patients with systemic lupus erythematosus: a case-control study.

OBJECTIVE: To assess the effect of treatment on interferon-alpha titer in the serum of female patients with systemic lupus erythematosus. METHODS: The case-control study was conducted at the Rheumatology Unit of Baghdad Teaching Hospital from January 2022 to April 2022 and comprised female systemic lupus erythematosus patients and healthy controls matched for age. The treated patients formed group A, while the untreated patients were placed in group B, and the controls were in group C. The disease severity status was confirmed using the systemic lupus erythematosus disease activity index. The serum level of interferon-alpha was determined using the enzyme-linked immunosorbent assay. Data was analysed using SPSS 21. RESULTS: Of the 150 subjects, 5033.3%) were in each of the 3 groups. The mean age of patients was 32.3±9 years while that of the controls was 33.0±11 years. Erythrocyte sedimentation rate, creatinine and aspartate aminotransferase were significantly higher in patient groups compared to the controls (p<0.05), while no-significant difference was noted between the treated and untreated groups (p>0.05). Interferon-alpha level was significantly high in group B compared to group A (p=0.037). The increase was more pronounced in those aged ≤50 years (p<0.05). Interferon-alpha was significantly high in group B patients with a disease duration of <1 year compared to group A (p=0.01). Interferon-alpha showed a significant increase in group B compared to the group A in patients with inactive systemic lupus erythematosus disease activity index and with family history (p<0.05). CONCLUSIONS: Treatment had a direct impact on interferon-alpha protein level in the serum of female patients of systemic lupus erythematosus.

Evaluation of some haematological, liver, and renal function biomarkers in different job categories at Kufa cement factory workers: a cross-sectional study.

Objective: To evaluate the workplace health-related environment of workers in various job categories at a cement factory. METHODS: The cross-sectional study was conducted at the Kufa Cement Factory, Najaf, Iraq, from November 12, 2021, to January 12, 2022 and comprised adult male non-smoking factory workers in group A, and healthy, unexposed non-smokers in control group B. Subjects in group A were subdivided into factory, kiln and packing workers. All the participants were subjected to blood tests for liver and kidney functions. Data was analysed using SPSS 27. RESULTS: Of the 90 subjects, 45(50%) were each of the 2 groups. The mean age of group A workers was 46.581±1.559 years and they had a mean duration of exposure 15.953±0.873 years. There were 15(33.3%) factory workers and as many kiln and packing workers. Group A subjects worked for at least 7-8 hours per day. The subjects in control group B had a mean age of 45.01±8.17 years and were matched for gender. There was significant elevation in total leukocyte count, alkaline phosphatase, aspartate aminotransferase and alanine aminotransferase in group A compared to group B (p<0.05). Neutrophils were significantly high in factory workers than controls and packing workers (p<0.05), while total bilirubin level was significantly high in factory and kiln workers than controls (p<0.05). There was no significant difference in the mean serum creatinine level between the groups (p>0.05). CONCLUSIONS: Workplace exposure to cement particulate in a factory environment was found to have a harmful impact on health.

Evaluation of the hepatoprotective effect of curcumin alone or in combination with vitamin C in methotrexate-induced hepatotoxicity in mice.

OBJECTIVE: To assess the hepatoprotective effect of curcumin and/or vitamin C in methotrexate-induced hepatotoxicity. METHODS: The experimental study was conducted at the Department of Pharmacology, College of Medicine, and the Iraqi Centre for Cancer and Medical Genetic Research, Mustansiriya University, Baghdad, Iraq, from Nov 12, 2020, to June 1, 2021, and comprised Swiss albino female mice aged 3-4 months and weighing 30-40g each. The mice were divided into 5 groups and treated for 10 days. Group 1 received distilled water, group 2 received single-dose methotrexate on the 10th day of the trial, group 3 was treated with curcumin plus methotrexate, group 4 was treated with vitamin C plus methotrexate, and group 5 was treated with curcumin and vitamin C plus methotrexate. Parameters measured were serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and lactate dehydrogenase, as well as hepatic tissue malondialdehyde, superoxide dismutase and glutathione. Data was analysed using SPSS 16. RESULTS: There were 35 mice; 7(20%) in each of the 5 groups. Hepatoprotection produced by curcumin as reflected by a decrease in lactate dehydrogenase and malondialdehyde levels was significant (p<0.05). Vitamin C also produced a significant hepatoprotection, demonstrated by a decrease in alanine aminotransferase, alkaline phosphatase, lactate dehydrogenase and malondialdehyde levels. The combination of curcumin and vitamin C reflected an additive effect demonstrated by a significant decrease in malondialdehyde (p<0.05). CONCLUSIONS: Curcumin and/or vitamin C provided hepatoprotection against methotrexate-induced hepatotoxicity through modulation of oxidative stress biomarkers.

The hepatoprotective potentials of Olea europaea L. leaves against carbon tetrachloride-induced hepatic injury in rats.

OBJECTIVE: To examine the therapeutic effects of Olea europaea L. leaves extract on carbon tetrachloride-induced liver injury in rats. Methods: The experimental study was conducted at the Department of Physiology, University of Karachi, Karachi, in July 2021, and comprised Albino Wistar male rats weighing 180-220gm. The animals were divided into control group I, carbon tetrachloride group II, Olea europaea L. + carbon tetrachloride group III and Olea europaea L. group IV. In Vitro model of hepatic toxicity was developed by carbon tetrachloride. A daily dose of 50mg/kg of aqueous extract of olive leaves was administered orally and 0.8ml/kg of carbon tetrachloride was administered twice a week subcutaneously for 28 days. On the 29th day, the animals were sacrificed, and tested for hepatic enzymes, lipid peroxidation markers and histopathology. Data was analysed using SPSS 20. RESULTS: Of the 24 rats, 6(25%) were in each of the 4 groups. Alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and total bilirubin levels were significantly reduced (p<0.05) in group II whereas, 4- hydroxynonenal, isoprostane and malondialdehyde levels were significantly increased (p<0.05). However, total antioxidant level increased significantly (p<0.05) in group III compared to group II. Histopathology showed severe liver damage in group II and mild damage in group III. Conclusion: Olea europaea L. leaves extract was found to have profound hepatoprotective effects.

Evolutionary origin and functional diversification of aminotransferases.

Aminotransferases (ATs) are pyridoxal 5'-phosphate-dependent enzymes that catalyze the transamination reactions between amino acid donor and keto acid acceptor substrates. Modern AT enzymes constitute ∼2% of all classified enzymatic activities, play central roles in nitrogen metabolism, and generate multitude of primary and secondary metabolites. ATs likely diverged into four distinct AT classes before the appearance of the last universal common ancestor and further expanded to a large and diverse enzyme family. Although the AT family underwent an extensive functional specialization, many AT enzymes retained considerable substrate promiscuity and multifunctionality because of their inherent mechanistic, structural, and functional constraints. This review summarizes the evolutionary history, diverse metabolic roles, reaction mechanisms, and structure-function relationships of the AT family enzymes, with a special emphasis on their substrate promiscuity and multifunctionality. Comprehensive characterization of AT substrate specificity is still needed to reveal their true metabolic functions in interconnecting various branches of the nitrogen metabolic network in different organisms.

Human cytosolic transaminases: side activities and patterns of discrimination towards physiologically available alternative substrates.

Transaminases play key roles in central metabolism, transferring the amino group from a donor substrate to an acceptor. These enzymes can often act, with low efficiency, on compounds different from the preferred substrates. To understand what might have shaped the substrate specificity of this class of enzymes, we examined the reactivity of six human cytosolic transaminases towards amino acids whose main degradative pathways do not include any transamination. We also tested whether sugars and sugar phosphates could serve as alternative amino group acceptors for these cytosolic enzymes. Each of the six aminotransferases reacted appreciably with at least three of the alternative amino acid substrates in vitro, albeit at usually feeble rates. Reactions with L-Thr, L-Arg, L-Lys and L-Asn were consistently very slow-a bias explained in part by the structural differences between these amino acids and the preferred substrates of the transaminases. On the other hand, L-His and L-Trp reacted more efficiently, particularly with GTK (glutamine transaminase K; also known as KYAT1). This points towards a role of GTK in the salvage of L-Trp (in cooperation with ω-amidase and possibly with the cytosolic malate dehydrogenase, MDH1, which efficiently reduced the product of L-Trp transamination). Finally, the transaminases were extremely ineffective at utilizing sugars and sugar derivatives, with the exception of the glycolytic intermediate dihydroxyacetone phosphate, which was slowly but appreciably transaminated by some of the enzymes to yield serinol phosphate. Evidence for the formation of this compound in a human cell line was also obtained. We discuss the biological and evolutionary implications of our results.

Is Endoscopy Mandatory In Cases Mimicking Acute Pancreatitis?

Objectives: To detect the utility of nonspecific rising of pancreatic enzymes in patients with stomach discomfort, and to explore the possibility of hyperamylasemia as a differential diagnosis. Method: The cross-sectional study was conducted from April 2020 to April 2021 at two large tertiary care centres in Kafrelsheikh and Zagazig governorates in northern Egypt, and comprised patients complaining of dull aching abdominal pain. They were classified into two groups. Patients with nonspecific rise in pancreatic enzymes less than threefold in the absence of acute pancreatitis were in group I, while those having abdominal pain without rise in pancreatic enzymes were in group II. All patients were subjected to detailed history and clinical examination followed by laboratory assessment, imaging studies and upper endoscopy. Data was analysed using SPSS 20. RESULTS: Of the 270 patients, 170(63%) were in group I; 120(70.5%) males and 50(29.5%) females with mean age 51±6.58 years, There were 100(37%) patientsin group II; 65(65%) males and 35(35%) females with mean age 53±8.96 years (p>0.05). Amylase, lipase, serum glutamic-oxaloacetic transaminase, serum glutamic-pyruvic transaminase, Creactive protein and helicobacter pylori values were significantly different between the groups (p<0.05). CONCLUSIONS: Elevation of pancreatic enzymes with a level less than three-fold in patients with abdominal pain reflected mucosal injury of the gastrointestinal tract and may raise the necessity for diagnostic upper endoscopy.

Clues to reaction specificity in PLP-dependent fold type I aminotransferases of monosaccharide biosynthesis.

Novel functions can emerge in an enzyme family while conserving catalytic mechanism, motif or fold. Pyridoxal 5'-phosphate-dependent enzymes have evolved into seven fold-types and catalyze diverse reactions using the same mechanism for the formation of external aldimine. Nucleotide sugar aminotransferases (which will be henceforth referred to as aminotransferases) belong to fold type I and mediate the biosynthesis of several monosaccharides. They use diverse substrates but are highly selective to the C3 or C4 carbon to which amine group is transferred. Profile hidden Markov models (HMMs) were able to identify aminotransferases but could not capture reaction specificity. A search for discriminating features led to the discovery of sequence motifs that are located near the pyranose binding site suggesting their role in imparting reaction specificity. Using a position weight matrix for this motif, we were able to assign reaction specificity to a large number of aminotransferases. Inferences from this analysis set way for future experiments that can shed light on mechanisms of functional diversification in nucleotide sugar aminotransferases of fold type I.

Nitrogen Metabolism in Pseudomonas putida: Functional Analysis Using Random Barcode Transposon Sequencing.

Pseudomonas putida KT2440 has long been studied for its diverse and robust metabolisms, yet many genes and proteins imparting these growth capacities remain uncharacterized. Using pooled mutant fitness assays, we identified genes and proteins involved in the assimilation of 52 different nitrogen containing compounds. To assay amino acid biosynthesis, 19 amino acid drop-out conditions were also tested. From these 71 conditions, significant fitness phenotypes were elicited in 672 different genes including 100 transcriptional regulators and 112 transport-related proteins. We divide these conditions into 6 classes, and propose assimilatory pathways for the compounds based on this wealth of genetic data. To complement these data, we characterize the substrate range of three promiscuous aminotransferases relevant to metabolic engineering efforts in vitro. Furthermore, we examine the specificity of five transcriptional regulators, explaining some fitness data results and exploring their potential to be developed into useful synthetic biology tools. In addition, we use manifold learning to create an interactive visualization tool for interpreting our BarSeq data, which will improve the accessibility and utility of this work to other researchers. IMPORTANCE Understanding the genetic basis of P. putida's diverse metabolism is imperative for us to reach its full potential as a host for metabolic engineering. Many target molecules of the bioeconomy and their precursors contain nitrogen. This study provides functional evidence linking hundreds of genes to their roles in the metabolism of nitrogenous compounds, and provides an interactive tool for visualizing these data. We further characterize several aminotransferases, lactamases, and regulators, which are of particular interest for metabolic engineering.

AST·MLR index and operation injury condition are novel prognostic predictor for the prediction of survival in patients with colorectal cancer liver metastases undergoing surgical resection.

BACKGROUND: The prognostic values of preoperative aspartate aminotransferase (AST), monocyte-to-lymphocyte ratio (MLR), AST·MLR index (AMLRI) and operation injury condition in patients with colorectal cancer liver metastases (CRLM) remains unclear. This retrospective study assessed the relationship between these markers, progression-free survival (PFS), and overall survival (OS) in CRLM patients undergoing resection. METHODS: AMLRI was defined as AST × MLR. Operation injury condition was defined according to operation time and blood loss. Cox regression analyses were used to identify risk factors and to develop nomograms. C-indexes, time-dependent receiver operating characteristic (time-ROC) curves and calibration curves were used to assess the models. RESULTS: A total of 379 patients were enrolled. The optimal cut-off value of the AMLRI was 3.33. In the multivariable analysis, AMLRI > 3.33 (hazard ratio [HR] = 2.162, p = 0.002) and serious operation injury condition (HR = 1.539, p = 0.012) were predictive for unfavourable OS, and AMLRI > 3.33 (HR = 1.462, p = 0.021) was predictive for unfavourable PFS. The nomograms were superior to Fong's Clinical Risk Score (CRS) according to the C-indexes (PFS: 0.682 vs. 0.600; OS: 0.730 vs. 0.586) and time-ROCs. CONCLUSIONS: Preoperative AMLRI and operation injury condition are easily accessible predictors for prognosis. The nomograms performed better than CRS for the prediction of recurrence and survival.

A new syndrome of moyamoya disease, kidney dysplasia, aminotransferase elevation, and skin disease associated with de novo variants in RNF213.

Ring-finger protein 213 (RNF213) encodes a protein of unknown function believed to play a role in cellular metabolism and angiogenesis. Gene variants are associated with susceptibility to moyamoya disease. Here, we describe two children with moyamoya disease who also demonstrated kidney disease, elevated aminotransferases, and recurrent skin lesions found by exome sequencing to have de novo missense variants in RNF213. These cases highlight the ability of RNF213 to cause Mendelian moyamoya disease in addition to acting as a genetic susceptibility locus. The cases also suggest a new, multi-organ RNF213-spectrum disease characterized by liver, skin, and kidney pathology in addition to severe moyamoya disease caused by heterozygous, de novo C-terminal RNF213 missense variants.

Influences of pregravid liver enzyme levels on the development of gestational diabetes mellitus.

BACKGROUND & AIMS: Elevated liver enzymes are associated with later development of type 2 diabetes mellitus. The objective of this study was to assess the association between prepregnancy liver enzyme levels and subsequent risk of gestational diabetes mellitus. METHODS: Data from a total of 236,109 women who participated in the National Health Screening Examination between 2011 and 2015 was analysed. Multivariate logistic regression analyses were performed to estimate the risk of developing gestational diabetes mellitus in relation to pregravid liver enzyme levels. Subgroup analyses were performed according to pregravid obesity and metabolic syndrome (MetS). RESULTS: Approximately 5.7% and 1.1% of women developed gestational diabetes mellitus with and without insulin treatment requirement respectively. Pregravid gamma-glutamyl transferase and alanine aminotransferase levels with greater than or equal to the 4th quartile were associated with significantly increased risks of gestational diabetes mellitus requiring insulin treatment in women with obesity and with MetS, (odds ratios [ORs] with 6.228 and 9.505, respectively, P < .001 for both). In women without obesity and without MetS, the risks of gestational diabetes mellitus requiring insulin treatment were also significant (ORs with 2.837 and 3.029, respectively, P < .001 for both). The elevated pregravid liver enzymes were associated with gestational diabetes mellitus without insulin treatment requirement, but minimally. CONCLUSIONS/INTERPRETATION: The elevated pregravid liver enzyme levels were significantly associated with the subsequent risk of gestational diabetes mellitus, especially gestational diabetes mellitus requiring insulin treatment, not only in women with obesity or MetS, but also in women without obesity or MetS.

Aminotransferases disorders associated with venous thromboembolic events in patients infected with COVID-19.

INTRODUCTION AND OBJECTIVES: Since the outbreak of the COVID-19 pandemic, increasing evidence suggests that infected patients present a high incidence of venous thromboembolic (VTE) events and elevated aminotransferases (AT).The objective of this work was to evaluate the incidence of aminotransferases disorders in patients infected with COVID-19 and to manage the VTE events associated with elevated AT. PATIENTS OR MATERIALS AND METHODS: We report a retrospective study of 46 patients admitted for COVID-19 infection. Venous duplex ultrasound of lower limbs was performed in all patients at Day 0 and Day 5. All patients had antithrombotic-prophylaxis upon admission using low molecular weight heparin with Enoxaparin. Demographics, comorbidities and laboratory parameters were collected and analyzed. RESULTS: Elevated AT were reported in 28 patients (61%). 10 had acute VTE events of which eight (17.4%) had aminotransferases disorders. They had been treated with curative Enoxaparin. After a follow-up of 15 and/or 30 days, six of them were controlled, and treated with direct oral anticoagulant (DOACs) after normalization of aminotransferases. CONCLUSIONS: The incidence of aminotransferases disorders associated with acute VTE events in patients infected with COVID-19 is significant. The use of DOACs appear pertinent in these patients. Monitoring of the liver balance should therefore be considered at a distance from the acute episode in the perspective of DOACs relay.

Prolonged abnormal isolated aminotransferase levels in healthy children is a benign condition.

AIM: Hypertransaminasaemia is a common incidental finding in children. It has been demonstrated that even prolonged elevation usually resolves spontaneously without clear aetiology. The aim of this study was to evaluate whether a longer follow-up period, on a larger group, supports the previous findings. METHODS: We retrospectively reviewed medical charts of children diagnosed with prolonged idiopathic hypertransaminasaemia, which spontaneously resolved over the follow-up period. RESULTS: Of the 468 patients screened for elevated transaminases levels, 87 patients younger than 5 years of age were included in the study. An aetiology was found in half of the patients, and the most common aetiologies were fatty liver and cytomegalovirus (CMV) infection. Aminotransferase abnormality persisted for a median of 10 months, and alanine aminotransferase (ALT) levels ranged from 1.5 to 15.9-fold of the upper limit of normal (ULN). After normalisation of transaminase levels, the values remained normal for a documented mean period of 6.4 ± 3.0 years. CONCLUSION: Although idiopathic asymptomatic aminotransferase elevation in healthy children resolves spontaneously in most children, the abnormality may be prolonged. Comprehensive workup finds aetiology only in half of the patients, and the most common aetiologies are fatty liver and CMV hepatitis, which can be diagnosed by non-invasive methods.

Conversion of Racemic Unnatural Amino Acids to Optically Pure Forms by a Coupled Enzymatic Reaction.

Genetic code expansion (GCE) technology is a useful tool for the site-specific modification of proteins. An unnatural amino acid (UAA) is one of the essential components of this technique, typically required at high concentration (1 mM or higher) in growth medium. The supply of UAAs is an important limitation to the application of GCE technology, as many UAAs are either expansive or commercially unavailable. In this study, two UAAs in a racemic mixture were converted into optically pure forms using two enzymes, the d-amino acid oxidase (RgDAAO) from Rhodotorula gracilis and the aminotransferase (TtAT) from Thermus thermophilus. In the coupled enzyme system, RgDAAO oxidizes the d-form of UAAs in a stereospecific manner and produces the corresponding α-keto acids, which are then converted into the l-form of UAAs by TtAT, resulting in the quantitative and stereospecific conversion of racemic UAAs to optically pure forms. The genetic incorporation of the optically pure UAAs into a target protein produced a better protein yield than the same experiments using the racemic mixtures of the UAAs. This method could not only be used for the preparation of optically pure UAAs from racemic mixtures, but also the broad substrate specificity of both enzymes would allow for its expansion to structurally diverse UAAs.