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Nature Reviews. Nephrology Aug 2020Hyperammonaemia in children can lead to grave consequences in the form of cerebral oedema, severe neurological impairment and even death. In infants and children, common... (Review)
Review
Hyperammonaemia in children can lead to grave consequences in the form of cerebral oedema, severe neurological impairment and even death. In infants and children, common causes of hyperammonaemia include urea cycle disorders or organic acidaemias. Few studies have assessed the role of extracorporeal therapies in the management of hyperammonaemia in neonates and children. Moreover, consensus guidelines are lacking for the use of non-kidney replacement therapy (NKRT) and kidney replacement therapies (KRTs, including peritoneal dialysis, continuous KRT, haemodialysis and hybrid therapy) to manage hyperammonaemia in neonates and children. Prompt treatment with KRT and/or NKRT, the choice of which depends on the ammonia concentrations and presenting symptoms of the patient, is crucial. This expert Consensus Statement presents recommendations for the management of hyperammonaemia requiring KRT in paediatric populations. Additional studies are required to strengthen these recommendations.
Topics: Arginine; Carnitine; Child; Child, Preschool; Continuous Renal Replacement Therapy; Delphi Technique; Diet, Protein-Restricted; Humans; Hybrid Renal Replacement Therapy; Hyperammonemia; Infant; Infant, Newborn; Parenteral Nutrition; Peritoneal Dialysis; Phenylacetates; Phenylbutyrates; Practice Guidelines as Topic; Renal Dialysis; Sodium Benzoate; Urea Cycle Disorders, Inborn; Vitamin B Complex
PubMed: 32269302
DOI: 10.1038/s41581-020-0267-8 -
Molecules (Basel, Switzerland) Sep 2023Catechols have important applications in the pharmaceutical, food, cosmetic, and functional material industries. 4-hydroxyphenylacetate-3-hydroxylase (4HPA3H), a... (Review)
Review
Catechols have important applications in the pharmaceutical, food, cosmetic, and functional material industries. 4-hydroxyphenylacetate-3-hydroxylase (4HPA3H), a two-component enzyme system comprising HpaB (monooxygenase) and HpaC (FAD oxidoreductase), demonstrates significant potential for catechol production because it can be easily expressed, is highly active, and exhibits -hydroxylation activity toward a broad spectrum of phenol substrates. HpaB determines the -hydroxylation efficiency and substrate spectrum of the enzyme; therefore, studying its structure-activity relationship, improving its properties, and developing a robust HpaB-conducting system are of significance and value; indeed, considerable efforts have been made in these areas in recent decades. Here, we review the classification, molecular structure, catalytic mechanism, primary efforts in protein engineering, and industrial applications of HpaB in catechol synthesis. Current trends in the further investigation of HpaB are also discussed.
Topics: Mixed Function Oxygenases; Catechols; Phenylacetates
PubMed: 37764475
DOI: 10.3390/molecules28186699 -
Clinical & Experimental Optometry Apr 2022The role of topical non-steroidal anti-inflammatory drugs (NSAIDs) in routine cataract surgery has been established since decades. Topical NSAIDs have been shown to... (Review)
Review
The role of topical non-steroidal anti-inflammatory drugs (NSAIDs) in routine cataract surgery has been established since decades. Topical NSAIDs have been shown to reduce postoperative ocular inflammation and pain, preserve intraoperative mydriasis, and reduce the risk of postoperative cystoid macular oedema, whilst carrying a very low side-effect profile. Nepafenac is one of the currently available topical NSAIDs. The studies have shown that is has a high ocular penetration, allowing for potentially better results than other NSAIDs. This review gathers the current literature on the role of nepafenac in cataract surgery aiming to help surgeons maximise the benefits of its use to achieve improved surgical outcomes.
Topics: Benzeneacetamides; Cataract; Cataract Extraction; Humans; Phenylacetates; Postoperative Complications
PubMed: 34210237
DOI: 10.1080/08164622.2021.1945412 -
Drug Metabolism and Pharmacokinetics Feb 2023TAK-123, a combination of sodium phenylacetate (NaPA) and sodium benzoate (NaBZ), is an intravenously administered drug developed for the treatment of acute...
TAK-123, a combination of sodium phenylacetate (NaPA) and sodium benzoate (NaBZ), is an intravenously administered drug developed for the treatment of acute hyperammonemia in infants, children, and adults with urea cycle enzyme deficiencies. The aim of the current study was to evaluate the pharmacokinetics, safety, and tolerability after intravenous infusion of TAK-123 in Japanese healthy adult volunteers. Ten volunteers received a 3.75 g/m loading dose of TAK-123 over a period of 1.5 h followed by a maintenance infusion of the same dose over 24 h. Phenylacetate (PA) and benzoate (BZ) and their respective metabolites, phenylacetylglutamine (PAG) and hippurate (HIP) were measured over a 24-h period using a high-performance liquid chromatography/tandem mass spectrometry method. Non-compartmental analysis was performed using WinNonlin® Professional. During the loading dose, plasma levels of both PA and BZ peaked at 1.5 h. Plasma PA levels plateaued and were maintained up to 6.5 h, whereas plasma BZ levels declined rapidly after switching to maintenance infusion. Urinary excretion ratios of PAG and HIP at 48 h after the administration were 99.3% and 104%, respectively, suggesting that almost all NaPA and NaBZ were metabolized and excreted into urine. Overall, TAK-123 was well-tolerated in healthy Japanese adults.
Topics: Adult; Child; Infant; Humans; Sodium Benzoate; East Asian People; Hyperammonemia; Phenylacetates; Benzoates; Healthy Volunteers
PubMed: 36529053
DOI: 10.1016/j.dmpk.2022.100474 -
Expert Opinion on Drug Metabolism &... Apr 2017Ammonia-scavenging drugs, benzoate and phenylacetate (PA)/phenylbutyrate (PB), modulate hepatic nitrogen metabolism mainly by providing alternative pathways for nitrogen... (Review)
Review
An update on the use of benzoate, phenylacetate and phenylbutyrate ammonia scavengers for interrogating and modifying liver nitrogen metabolism and its implications in urea cycle disorders and liver disease.
Ammonia-scavenging drugs, benzoate and phenylacetate (PA)/phenylbutyrate (PB), modulate hepatic nitrogen metabolism mainly by providing alternative pathways for nitrogen disposal. Areas covered: We review the major findings and potential novel applications of ammonia-scavenging drugs, focusing on urea cycle disorders and liver disease. Expert opinion: For over 40 years, ammonia-scavenging drugs have been used in the treatment of urea cycle disorders. Recently, the use of these compounds has been advocated in acute liver failure and cirrhosis for reducing hyperammonemic-induced hepatic encephalopathy. The efficacy and mechanisms underlying the antitumor effects of these ammonia-scavenging drugs in liver cancer are more controversial and are discussed in the review. Overall, as ammonia-scavenging drugs are usually safe and well tolerated among cancer patients, further studies should be instigated to explore the role of these drugs in liver cancer. Considering the relevance of glutamine metabolism to the progression and resolution of liver disease, we propose that ammonia-scavenging drugs might also be used to non-invasively probe liver glutamine metabolism in vivo. Finally, novel derivatives of classical ammonia-scavenging drugs with fewer and less severe adverse effects are currently being developed and used in clinical trials for the treatment of acute liver failure and cirrhosis.
Topics: Ammonia; Animals; Benzoates; Drug Design; Glutamine; Humans; Liver Cirrhosis; Liver Diseases; Liver Failure, Acute; Nitrogen; Phenylacetates; Phenylbutyrates; Urea Cycle Disorders, Inborn
PubMed: 27860485
DOI: 10.1080/17425255.2017.1262843 -
Journal of Veterinary Pharmacology and... Jul 2022Robenacoxib is a veterinary-approved non-steroidal anti-inflammatory drug (NSAID) of the coxib group. It possesses anti-hyperalgesic, anti-inflammatory and anti-pyretic... (Review)
Review
Robenacoxib is a veterinary-approved non-steroidal anti-inflammatory drug (NSAID) of the coxib group. It possesses anti-hyperalgesic, anti-inflammatory and anti-pyretic properties. Robenacoxib inhibits the cyclooxygenase (COX)-2 isoform of COX selectively (in vitro IC ratios COX-1:COX-2, 129:1 in dogs, 32:1 in cats). At registered dosages (2 mg/kg subcutaneously in dogs and cats, 1-4 mg/kg orally in dogs and 1-2.4 mg/kg orally in cats), robenacoxib produces significant inhibition of COX-2 whilst sparing COX-1. The pharmacokinetic (PK) profile of robenacoxib is characterized by a high degree of binding to plasma proteins (>98%) and moderate volume of distribution (at steady state, 240 ml/kg in dogs and 190 ml/kg in cats). In consequence, the terminal half-life in blood (<2 h) is short, despite moderate body clearance (0.81 L/kg/h) in dogs and low clearance (0.44 L/kg/h) in cats. Excretion is principally in the bile (65% in dogs and 72% in cats). Robenacoxib concentrates in inflamed tissues, and clinical efficacy is achieved with once-daily dosing, despite the short blood terminal half-life. In dogs, no relevant breed differences in robenacoxib PK have been detected. Robenacoxib has a wide safety margin; in healthy laboratory animals daily oral doses 20-fold (dog, 1 month), eight-fold (cat, 6 weeks) and five-fold (dog, 6 months) higher than recommended clinical doses were well tolerated. Clinical efficacy and safety have been demonstrated in orthopaedic and soft tissue surgery, and in musculoskeletal disorders in dogs and cats.
Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Cat Diseases; Cats; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Diphenylamine; Dog Diseases; Dogs; Phenylacetates
PubMed: 35460083
DOI: 10.1111/jvp.13052 -
Molecules (Basel, Switzerland) Oct 2022A new series of cytotoxic platinum(IV) complexes (-) incorporating halogenated phenylacetic acid derivatives (4-chlorophenylacetic acid, 4-fluorophenylacetic acid,...
A new series of cytotoxic platinum(IV) complexes (-) incorporating halogenated phenylacetic acid derivatives (4-chlorophenylacetic acid, 4-fluorophenylacetic acid, 4-bromophenylacetic acid and 4-iodophenylacetic acid) were synthesised and characterised using spectroscopic and spectrometric techniques. Complexes - were assessed on a panel of cell lines including HT29 colon, U87 glioblastoma, MCF-7 breast, A2780 ovarian, H460 lung, A431 skin, Du145 prostate, BE2-C neuroblastoma, SJ-G2 glioblastoma, MIA pancreas, the ADDP-resistant ovarian variant, and the non-tumour-derived MCF10A breast line. The in vitro cytotoxicity results confirmed the superior biological activity of the studied complexes, especially those containing 4-fluorophenylacetic acid and 4-bromophenylacetic acid ligands, namely and , eliciting an average GI value of 20 nM over the range of cell lines tested. In the Du145 prostate cell line, exhibited the highest degree of potency amongst the derivatives, displaying a GI value of 0.7 nM, which makes it 1700-fold more potent than cisplatin (1200 nM) and nearly 7-fold more potent than our lead complex, (4.6 nM) in this cell line. Notably, in the ADDP-resistant ovarian variant cell line, (6 nM) was found to be almost 4700-fold more potent than cisplatin. Reduction reaction experiments were also undertaken, along with studies aimed at determining the complexes' solubility, stability, lipophilicity, and reactive oxygen species production.
Topics: Humans; Female; Platinum; Cisplatin; Cell Line, Tumor; Reactive Oxygen Species; Glioblastoma; Ovarian Neoplasms; Antineoplastic Agents; Phenylacetates
PubMed: 36296713
DOI: 10.3390/molecules27207120 -
Scientific Reports Oct 2017Urea cycle enzyme deficiency (UCED) patients with hyperammonemia are treated with sodium benzoate (SB) and sodium phenylacetate (SPA) to induce alternative pathways of...
Urea cycle enzyme deficiency (UCED) patients with hyperammonemia are treated with sodium benzoate (SB) and sodium phenylacetate (SPA) to induce alternative pathways of nitrogen excretion. The suggested guidelines supporting their use in the management of hyperammonemia are primarily based on non-analytic studies such as case reports and case series. Canine congenital portosystemic shunting (CPSS) is a naturally occurring model for hyperammonemia. Here, we performed cross-over, randomized, placebo-controlled studies in healthy dogs to assess safety and pharmacokinetics of SB and SPA (phase I). As follow-up safety and efficacy of SB was evaluated in CPSS-dogs with hyperammonemia (phase II). Pharmacokinetics of SB and SPA were comparable to those reported in humans. Treatment with SB and SPA was safe and both nitrogen scavengers were converted into their respective metabolites hippuric acid and phenylacetylglutamine or phenylacetylglycine, with a preference for phenylacetylglycine. In CPSS-dogs, treatment with SB resulted in the same effect on plasma ammonia as the control treatment (i.e. saline infusion) suggesting that the decrease is a result of volume expansion and/or forced diuresis rather than increased production of nitrogenous waste. Consequentially, treatment of hyperammonemia justifies additional/placebo-controlled trials in human medicine.
Topics: Animals; Dogs; Female; Hyperammonemia; Male; Nitrogen; Phenylacetates; Random Allocation; Saline Waters; Sodium Benzoate
PubMed: 29030642
DOI: 10.1038/s41598-017-12686-9 -
Biosensors Nov 2021A novel, integrated experimental and modeling framework was applied to an inhibition-based bi-enzyme (IBE) electrochemical biosensor to detect acetylcholinesterase...
A novel, integrated experimental and modeling framework was applied to an inhibition-based bi-enzyme (IBE) electrochemical biosensor to detect acetylcholinesterase (AChE) inhibitors that may trigger neurological diseases. The biosensor was fabricated by co-immobilizing AChE and tyrosinase (Tyr) on the gold working electrode of a screen-printed electrode (SPE) array. The reaction chemistry included a redox-recycle amplification mechanism to improve the biosensor's current output and sensitivity. A mechanistic mathematical model of the biosensor was used to simulate key diffusion and reaction steps, including diffusion of AChE's reactant (phenylacetate) and inhibitor, the reaction kinetics of the two enzymes, and electrochemical reaction kinetics at the SPE's working electrode. The model was validated by showing that it could reproduce a steady-state biosensor current as a function of the inhibitor (PMSF) concentration and unsteady-state dynamics of the biosensor current following the addition of a reactant (phenylacetate) and inhibitor phenylmethylsulfonylfluoride). The model's utility for characterizing and optimizing biosensor performance was then demonstrated. It was used to calculate the sensitivity of the biosensor's current output and the redox-recycle amplification factor as a function of experimental variables. It was used to calculate dimensionless Damkohler numbers and current-control coefficients that indicated the degree to which individual diffusion and reaction steps limited the biosensor's output current. Finally, the model's utility in designing IBE biosensors and operating conditions that achieve specific performance criteria was discussed.
Topics: Acetylcholinesterase; Biosensing Techniques; Cholinesterase Inhibitors; Electrochemical Techniques; Electrodes; Enzymes, Immobilized; Monophenol Monooxygenase; Phenylacetates
PubMed: 34821676
DOI: 10.3390/bios11110459 -
British Medical Journal (Clinical... May 1982
Topics: Chemical and Drug Induced Liver Injury; Diagnosis, Differential; Diclofenac; Hepatitis; Humans; Male; Middle Aged; Phenylacetates
PubMed: 6805622
DOI: 10.1136/bmj.284.6329.1605