Blood metabolites in preterm infants with retinopathy of prematurity based on tandem mass spectrometry: a preliminary study / 中国当代儿科杂志

OBJECTIVES@#To study new biomarkers for the early diagnosis of retinopathy of prematurity (ROP) by analyzing the differences in blood metabolites based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) and metabolomics.@*METHODS@#Dried blood spots were collected from 21 infants with ROP (ROP group) and 21 infants without ROP (non-ROP group) who were hospitalized in the Sixth Affiliated Hospital of Sun Yat-sen University from January 2013 to December 2016. LC-MS/MS was used to measure the metabolites, and orthogonal partial least squares-discriminant analysis was used to search for differentially expressed metabolites and biomarkers.@*RESULTS@#There was a significant difference in blood metabolic profiles between the ROP and non-ROP groups. The pattern recognition analysis, Score-plot, and weight analysis obtained 10 amino acids with a relatively large difference. Further statistical analysis showed that the ROP group had significant increases in blood levels of glutamic acid, leucine, aspartic acid, ornithine, and glycine compared with the non-ROP group (P<0.05). The receiver operating characteristic curve analysis showed that glutamic acid and ornithine had the highest value in diagnosing ROP.@*CONCLUSIONS@#Blood metabolites in preterm infants with ROP are different from those without ROP. Glutamic acid and ornithine are the metabolic markers for diagnosing ROP. LC-MS/MS combined with metabolomics analysis has a potential application value in the early identification and diagnosis of ROP.

Optimization of a cucurbit6uril-based real-time label-free method for analyzing the activity of ornithine decarboxylase / 生物工程学报

Ornithine decarboxylase (ODC) is a key enzyme in the biosynthetic pathway of polyamines and catalyzes the decarboxylation of ornithine to produce putrescine. Inhibition of ODC activity is a potential approach for the prevention and treatment of many diseases including cancer, as the expression levels and the activities of ODC in many abnormal cells and tumor cells are generally higher than those of normal cells. The discovery and evaluation of ODC inhibitors rely on the monitoring of the reaction processes catalyzed by ODC. There are several commonly used methods for analyzing the activity of ODC, such as measuring the yield of putrescine by high performance liquid chromatography, or quantifying the yield of isotope labelled carbon dioxide. However, the cumbersome operation and cost of these assays, as well as the difficulty to achieve high-throughput and real-time detection, hampered their applications. In this work, we optimized a real-time label-free method for analyzing the activity of ODC based on the macromolecule cucurbit[6]uril (CB6) and a fluorescent dye, DSMI (trans-4-[4-(dimethylamino) styryl]-1-methylpyridinium iodide). Finally, the optimized method was used to determine the activities of different ODC inhibitors with different inhibition mechanisms.

Decreased plasmatic spermidine and increased spermine in mild cognitive impairment and Alzheimer's disease patients

Abstract Background Current evidence suggests that upregulation of polyamines system plays a role both in cognitive deficit and synaptic loss observed in Alzheimer's disease (AD). Objective The aim of this study was to determine the plasmatic concentration of polyamines in mild cognitive impairment (MCI) and AD patients in comparison with healthy controls (HC). Methods Plasmatic polyamines were quantified using the AbsoluteIDQ® p180 and liquid chromatography coupled to tandem mass spectrometry (LC/MS-MS). Results The study group comprised 34 AD patients, 20 MCI and 25 HC. All individuals were followed for 4 years. During this period 8 amnestic MCI patients (40% of the MCI sample at baseline) converted to AD. Spermidine level was lower in both patient groups (AD; MCI) compared to HC (p = 0.007). Plasma levels of spermine were higher in the MCI group (p < 0.001), but decreased in the sub-sample of MCI patients who converted to AD (p = 0.043). No statistically significant differences were found in ornithine and putrescine levels (p = 0.056 and p = 0.126, respectively). Discussion Our results suggest dynamic changes in the expression of polyamines in the MCI-AD continuum.

Papel de las poliaminas en la transducción de señales intracelulares: posibles proyec­ciones de uso clínico en el manejo de las distrofias musculares por medio de su inhibi­ción con difluorometilornitina / Polyamines role in intracellular signals transduction: possible projections for clinical use in muscular dy strophies ' management through its inhibition with difluoromethylornithine

Las distrofias musculares de origen genético son muy diversas y, tanto su diagnóstico preciso como su manejo, suponen un reto importante. En cuanto a este último aspecto, no obstante el desarrollo en proceso de nuevas estrategias a nivel molecular para su tratamiento, las herramientas con que se cuenta para este propósito son limitadas, y pocas veces pueden influir de manera efectiva para evitar el deterioro progresivo que muchos de estos pacientes experimentan. Además, las terapias de última generación no abarcan la gran diversidad de estas patologías y no se espera que estén disponibles a corto plazo para la mayoría de los pacientes. El propósito del artículo es mostrar el papel de las poliaminas, actores ubicuos en el metabolismo in­ tracelular tal vez poco conocidos; cómo están involucrados en los procesos fisiológicos y patológicos, y cómo también pudiesen estar involucrados en la fisiopatología de las distrofias musculares. Su inhi­bición controlada, mediante Difluorometilornitina (DFMO), pudiese constituir un mecanismo para en­ lentecer o eliminar el deterioro muscular de estos pacientes, al utilizarse como una herramienta dentro del arsenal de las ya existentes

Muscular dystrophies of genetic origin are very diverse and, both their precise diagnosis and their management represent an important challenge. Regarding this last aspect, despite the development in process of new strategies at the molecular level for its treatment, the tools available for this pur­ pose are limited, and can rarely influence effectively to avoid the progressive deterioration that many of these patients experience. In addition, the lates t­generation therapies do not cover the great diversity of these pathologies and are not expected to be available in the short term for most patients. The purpose of the article is to show the role of polyamines, ubiquitous actors in intracellular meta­ bolism, perhaps little known; how they are involved in physiological and pathological processes, and how they could also be involved in the physiopathology of muscular dystrophies. Its controlled inhi­ bition, by difluoromethylilitin (DFMO), could be a mechanism to slow or eliminate the muscle deterio­ ration of these patients, by being used as a tool within the arsenal of those already existing.

Screening of medium constituents for clavulanic acid production by Streptomyces clavuligerus

ABSTRACT Clavulanic acid is a β-lactam compound with potent inhibitory activity against β-lactamases. Studies have shown that certain amino acids play essential roles in CA biosynthesis. However, quantitative evaluations of the effects of these amino acids are still needed in order to improve CA production. Here, we report a study of the nutritional requirements of Streptomyces clavuligerus for CA production. Firstly, the influence of the primary nitrogen source and the salts composition was investigated. Subsequently, soybean protein isolate was supplemented with arginine (0.0-3.20 g L-1), threonine (0.0-1.44 g L-1), ornithine (0.0-4.08 g L-1), and glutamate (0.0-8.16 g L-1), according to a two-level central composite rotatable design. A medium containing ferrous sulfate yielded CA production of 437 mg L-1, while a formulation without this salt produced only 41 mg L-1 of CA. This substantial difference suggested that Fe2+ is important for CA biosynthesis. The experimental design showed that glutamate and ornithine negatively influenced CA production while arginine and threonine had no influence. The soybean protein isolate provided sufficient C5 precursor for CA biosynthesis, so that supplementation was unnecessary. Screening of medium components, together with experimental design tools, could be a valuable way of enhancing CA titers and reducing the process costs.

A 14-20 kDa protein binds to the upstream region of the phtM operon involved in the synthesis of phaseolotoxin in Pseudomonas syringae pv. phaseolicola NPS3121 / Una proteína de 14-20 kDa se une a la región río arriba del operón phtM involucrado en la síntesis de faseolotoxina en Pseudomonas syringae pv. phaseolicola NPS3121

Pseudomonas syringae pv. phaseolicola is a phytopathogenic bacterium in beans that produces a phytotoxin called phaseolotoxin, in whose synthesis a group of genes that belong to the "Pht cluster" are involved. This cluster comprises 23 genes arranged in 5 transcriptional units, two monocistronic (argK, phtL) and three polycistronic (phtA, phtD, phtM) operons, whose expression is increased at 18°C, correlating with the production of phaseolotoxin by the bacterium. So far, the regulatory mechanisms involved in phaseolotoxin synthesis are poorly understood and only the requirement of low temperatures for its synthesis has been demon strated. Therefore, in this study we searched for regulatory proteins that could be involved in the phaseolotoxin synthesis, focusing on the regulation of the phtM operon. Gel shift assays showed that the promoter region of the phtM operon contains binding sites for putative regulatory proteins, which are encoded outside the Pht cluster and are independent of the GacS-GacA two-component system. Deletion assays with the promoter region of the phtM operon show that the binding site for a putative transcription factor is located within a 58 bp region. The putative transcription factor of the phtM operon has an apparent molecular mass in the 14-20 kDa range. Furthermore, the results demonstrate that the transcription factor recognizes and binds the upstream phtM region as monomer o multimer of a single polypeptide. Our findings provide new insights into the regulatory mechanisms involved in phaseolotoxin production, and suggest that the Pht cluster was integrated into the global regulatory mechanism of P. syringae pv. phaseolicola.

Aspartato de ornitina para o tratamento da hiperamonemia produzida por doenças hepáticas agudas e crônicas / Ornithine aspartate for the treatment of hyperammonemia caused by acute and chronic liver diseases

CONTEXTO: A hiperamonemia é caracterizada pelo elevado nível de amônia na corrente sanguínea, decorrente de falhas no catabolismo de aminoácidos ou amônia para uréia. As doenças hepáticas são as causas mais comuns de hiperamonemia em adultos. Podem ser agudas, como por exemplo, hepatites virais, isquemia, ou hepatotoxinas, ou crônicas, como cirrose hepática, hepatites, atresia biliar, deficiência de alfa1-antitripsina; doença de Wilson; fibrose cística; galactosemia e tirosinemia. A encefalopatia hepática (EH) é uma complicação neuropsiquiátrica frequente nos portadores de doenças hepáticas e caracteriza-se por distúrbios da atenção, alterações do sono e distúrbios motores que progridem desde simples letargia a estupor ou coma. É um distúrbio metabólico, portanto potencialmente reversível, sendo a hiperamonemia, o principal fator dessa condição. São alternativas terapêuticas, os dissacarídeos não absorvíveis (lactulose e lactitol), antibióticos orais não absorvíveis, BCAA (aminoácidos de cadeia ramificada) e probióticos. No SUS, a lactulose é a alternativa disponível para tratar essa condição. TECNOLOGIA: Aspartato de ornitina (Hepa-Merz®). INDICAÇÃO: Hiperamonemia produzida por doenças hepáticas agudas e crônicas. PERGUNTA: O uso do aspartato de ornitina é eficaz e seguro no tratamento da hiperamonemia produzida por doenças hepáticas agudas e crônicas? EVIDÊNCIAS CIENTÍFICAS: Foram encontrados 6 estudos, sendo 2 revisões sistemáticas, 3 ensaios clínicos e 1 parecer técnico-científico. As evidências demonstraram um benefício provável no uso do aspartato de ornitina em comparação à não intervenção ou placebo no tratamento da hiperamonemia decorrente de doenças hepáticas, predominantemente crônicas e presença de cirrose. Entretanto, comparado à lactulose, alternativa disponível no SUS e demais intervenções, não foi observado benefício adicional. AVALIAÇÃO ECONÔMICA: Foi realizada uma avaliação econômica com um modelo de custominimização. Para a realização dos cálculos, foram considerados somente os custos de aquisição dos medicamentos. Os resultados demonstram que a lactulose pode ser até 76% menos custosa que o aspartato de ornitina oral. AVALIAÇÃO DE IMPACTO ORÇAMENTÁRIO: A Secretaria-Executiva da CONITEC calculou o impacto orçamentário em um cenário base que considera uma divisão de mercado (Market-share) gradual de até 70% em 2021, considerando uma perspectiva de horizonte temporal de 5 anos. A quantidade de pacientes elegíveis foi estimada utilizando dados prevalência encontrados na literatura. Os custos de tratamento considerados foram aqueles já utilizados nas compras do Ministério da Saúde ou encontrados em busca no Banco de Preços em Saúde. O impacto orçamentário resultante da incorporação do aspartato de ornitina seria de um incremento de aproximadamente 15,3 milhões de reais em 5 anos após a incorporação. EXPERIÊNCIA INTERNACIONAL: Não foram encontradas avaliações sobre o aspartato de ornitina para tratamento da encefalopatia hepática ou hiperamonemia nas agências NICE (Inglaterra), CADTH (Canadá), SMC (Escócia) e PBAC (Austrália). DISCUSSÃO: Os resultados não demonstraram superioridade do aspartato de ornitina em relação á lactulose, alternativa disponível no SUS. A despeito dos resultados favoráveis ao aspartato de ornitina quando comparado com placebo/não intervenção, evidências robustas apontam efeito benéfico também da lactulose/lactitol sobre resultados clinicamente relevantes quando comparados à placebo/nenhuma intervenção, com destaque para o desfecho de mortalidade. Por fim, em um cenário de incorporação do aspartato de ornitina, haverá incremento importante no impacto orçamentário. RECOMENDAÇÃO DA CONITEC: Os membros da CONITEC, presentes na 54ª reunião ordinária, realizada nos dias 5 e 6 de abril de 2017, apreciaram a proposta e decidiram que a matéria seria disponibilizada em Consulta Pública com recomendação preliminar desfavorável à incorporação do aspartato de ornitina para o tratamento hiperamonemia produzida por doenças hepáticas agudas e crônicas. CONSULTA PÚBLICA: Foi realizada a Consulta Pública nº 16/2017 sobre o relatório de recomendação da CONITEC "Aspartato de ornitina para o tratamento da hiperamonemia produzida por doenças hepáticas agudas e crônicas" entre os dias 13/04/2017 e 02/05/2017. Foram recebidas 10 contribuições, sendo 8 pelo formulário para contribuições sobre experiência ou opinião e 2 pelo formulário para contribuições técnico-científicas. A maioria das contribuições foram contrárias à recomendação inicial da CONITEC. DELIBERAÇÃO FINAL: Os membros da CONITEC presentes na 56ª reunião do plenário do dia 07/06/2017 deliberaram por unanimidade recomendar a não incorporação do aspartato de ornitina para o tratamento da hiperamonemia produzida por doenças hepáticas agudas e crônicas, com a ressalva de que o Ministério da Saúde reformulará a demanda, especificando a população. Foi assinado o registro de deliberação nº 261/2017.(AU)

A Novel SLC25A15 Mmutation Causing Hyperornithinemia-Hyperammonemia-Homocitrullinuria Syndrome

Hyperornithinemia-hyperammonemia-homocitrullinuria syndrome (HHH syndrome) is a neurometabolic disorder with highly variable clinical severity ranging from mild learning disability to severe encephalopathy. Diagnosis of HHH syndrome can easily be delayed or misdiagnosed due to insidious symptoms and incomplete biochemical findings, in that case, genetic testing should be considered to confirm the diagnosis. HHH syndrome is caused by biallelic mutations of SLC25A15, which is involved in the urea cycle and the ornithine transport into mitochondria. Here we report a boy with spastic paraplegia and asymptomatic younger sister who have compound heterozygous mutations of c.535C>T (p.R179*) and c.116C>A (p.T39K) in the SLC25A15 gene. We identified that p.T39K mutation is a novel pathogenic mutation causing HHH syndrome and that p.R179*, which is prevalent in Japanese and Middle Eastern heritage, is also found in the Korean population.

Lethal Hyperammonemia due to Ornithine Transcarbamylase Deficiency in a Patient with Severe Septic Shock / 대한구급학회지

Severe hyperammonemia can occur as a result of inherited or acquired liver enzyme defects in the urea cycle, among which ornithine transcarbamylase deficiency (OTCD) is the most common form. We report a very rare case of a 45-year-old Korean male who was admitted to the intensive care unit (ICU) due to severe septic shock with acute respiratory failure caused by Pneumocystis jiroveci pneumonia. During his ICU stay with ventilator care, the patient suffered from marked hyperammonemia (>1,700 µg/dL) with abrupt mental change leading to life-threatening cerebral edema. Despite every effort including continuous renal replacement therapy and use of a molecular adsorbent recirculating system (extracorporeal liver support-albumin dialysis) to lower his serum ammonia level, the patient was not recovered. The lethal hyperammonemia in the patient was later proven to be a manifestation of acquired liver enzyme defect known as OTCD, which is triggered by serious catabolic conditions, such as severe septic shock with acute respiratory failure.

Lethal Hyperammonemia due to Ornithine Transcarbamylase Deficiency in a Patient with Severe Septic Shock / 대한중환자의학회지

Severe hyperammonemia can occur as a result of inherited or acquired liver enzyme defects in the urea cycle, among which ornithine transcarbamylase deficiency (OTCD) is the most common form. We report a very rare case of a 45-year-old Korean male who was admitted to the intensive care unit (ICU) due to severe septic shock with acute respiratory failure caused by Pneumocystis jiroveci pneumonia. During his ICU stay with ventilator care, the patient suffered from marked hyperammonemia (>1,700 µg/dL) with abrupt mental change leading to life-threatening cerebral edema. Despite every effort including continuous renal replacement therapy and use of a molecular adsorbent recirculating system (extracorporeal liver support-albumin dialysis) to lower his serum ammonia level, the patient was not recovered. The lethal hyperammonemia in the patient was later proven to be a manifestation of acquired liver enzyme defect known as OTCD, which is triggered by serious catabolic conditions, such as severe septic shock with acute respiratory failure.

Quinolone resistance and ornithine decarboxylation activity in lactose-negative Escherichia coli

Quinolones and fluoroquinolones are widely used to treat uropathogenic Escherichia coli infections. Bacterial resistance to these antimicrobials primarily involves mutations in gyrA and parC genes. To date, no studies have examined the potential relationship between biochemical characteristics and quinolone resistance in uropathogenic E. coli strains. The present work analyzed the quinolone sensitivity and biochemical activities of fifty-eight lactose-negative uropathogenic E. coli strains. A high percentage of the isolates (48.3%) was found to be resistant to at least one of the tested quinolones, and DNA sequencing revealed quinolone resistant determining region gyrA and parC mutations in the multi-resistant isolates. Statistical analyses suggested that the lack of ornithine decarboxylase (ODC) activity is correlated with quinolone resistance. Despite the low number of isolates examined, this is the first study correlating these characteristics in lactose-negative E. coli isolates.

Influence of environmental hypertonicity on the induction of ureogenesis and amino acid metabolism in air-breathing walking catfish (Clarias batrachus, Bloch).

Effect of environmental hypertonicity, due to exposure to 300 mM mannitol solution for 7 days, on the induction of ureogenesis and also on amino acid metabolism was studied in the air-breathing walking catfish, C. batrachus, which is already known to have the capacity to face the problem of osmolarity stress in addition to other environmental stresses in its natural habitats. Exposure to hypertonic mannitol solution led to reduction of ammonia excretion rate by about 2-fold with a concomitant increase of urea-N excretion rate by about 2-fold. This was accompanied by significant increase in the levels of both ammonia and urea in different tissues and also in plasma. Further, the environmental hypertonicity also led to significant accumulation of different non-essential free amino acids (FAAs) and to some extent the essential FAAs, thereby causing a total increase of non-essential FAA pool by 2-3-fold and essential FAA pool by 1.5-2.0-fold in most of the tissues studied including the plasma. The activities of three ornithine-urea cycle (OUC) enzymes such as carbamoyl phosphate synthetase, argininosuccinate synthetase and argininosuccinate lyase in liver and kidney tissues, and four key amino acid metabolism-related enzymes such as glutamine synthetase, glutamate dehydrogenase (reductive amination), alanine aminotransaminase and aspartate aminotransaminase were also significantly up-regulated in different tissues of the fish while exposing to hypertonic environment. Thus, more accumulation and excretion of urea-N observed during hypertonic exposure were probably associated with the induction of ureogenesis through the induced OUC, and the increase of amino acid pool was probably mainly associated with the up-regulation of amino acid synthesizing machineries in this catfish in hypertonic environment. These might have helped the walking catfish in defending the osmotic stress and to acclimatize better under hypertonic environment, which is very much uncommon among freshwater teleosts.

Glutamine and ornithine alpha-ketoglutarate supplementation on malate dehydrogenases expression in hepatectomized rats

PURPOSE: To evaluate the relative gene expression (RGE) of cytosolic (MDH1) and mitochondrial (MDH2) malate dehydrogenases enzymes in partially hepatectomized rats after glutamine (GLN) or ornithine alpha-ketoglutarate (OKG) suplementation. METHODS: One-hundred and eight male Wistar rats were randomly distributed into six groups (n=18): CCaL, GLNL and OKGL and fed calcium caseinate (CCa), GLN and OKG, 0.5g/Kg by gavage, 30 minutes before laparotomy. CCaH, GLNH and OKGH groups were likewise fed 30 minutes before 70% partial hepatectomy. Blood and liver samples were collected three, seven and 14 days after laparotomy/hepatectomy for quantification of MDH1/MDH2 enzymes using the real-time polymerase chain reaction (PCR) methodology. Relative enzymes expression was calculated by the 2-ΔΔC T method using the threshold cycle (CT) value for normalization. RESULTS: MDH1/MDH2 RGE was not different in hepatectomized rats treated with OKG compared to rats treated with CCa. However, MDH1/MDH2 RGE was greater on days 3 (321:1/26.48:1) and 7 (2.12:1/2.48:1) while MDH2 RGE was greater on day 14 (7.79:1) in hepatectomized rats treated with GLN compared to control animals. CONCLUSION: Glutamine has beneficial effects in liver regeneration in rats by promoting an up-regulation of the MDH1 and MDH2 relative gene expression. .

[ study on the effects of supplementary L-arginine and L-ornithine on the growth indices in rainbow trout, Oncorhynchus mykiss]

Fish are useful models for physiological studies in which using nutritional, growth and hormonal indices can lead to the understanding of several biological mechanisms in vertebrates. In this study, the effects of the addition of two amino acids, L-arginine and L-ornithine, to a commercial feed on the growth indices and the blood levels of insulin-like growth factor-I [IGF-I] of rainbow trout, Oncorhynchus mykiss were examined. The fish [average initial weight 45 +/- 4 g] were fed for 8 weeks with one of the following 4 dietary treatments: Commercial trout diet supplemented with 2% L-arginine-[T1] 2% L-ornithine-[T2] 2% L-arginine + 1% L-ornithine-[T3]; 3% L-arginine + 1% L-ornithine-[T4] and the commercial feed without addition of the amino acids [controls]. According to the results, maximum weight gain [268.94 +/- 5.84%] and specific growth rate [SGR] [2.33 +/- 0.05% day-1] were observed in the fish of group T3, while maximum hepatosomatic index [HSI] [1.49 +/- 0.04%] was recorded in group T4. These amounts were significantly higher than their counterpart indices of the control group [P<0.05]. Supplementing the feed with the amino acids, overall, increased IGF-I levels throughout the study period. At the end of the eighth week, in the T3 and control groups maximum and minimum IGF levels were 1180 pg/ml and 980.35 pg/ml respectively. Results of this study showed the positive effects of providing fish diet with additional amino acids, especially a combination of arginine and ornithine, on growth promotion in rainbow trout

Research on the treatment of liver failure rats with transplantation of alginate microencapsulated hepatocytes in vivo based on poly-ornithine / 生物医学工程学杂志

This study aims to explore the effects of alginate-poly ornithine-alginate (A-PLO-A) and barium alginate-poly ornithine-alginate (B-PLO-A) microcapsules as cells carriers during implantation. Mice hepatocytes coated in A-PLO-A and B-PLO-A microcapsules were implanted into rats with acute liver failure caused by intraperitoneal injection of D-galactosamine. The rat survival rate, liver cell growth, proliferation and metabolism within the microcapsules were investigated, as well as its effect on the improvement of rat acute liver failure. The influence of A-PLO-A-free microcapsules, B-PLO-A-free microcapsules, isolated liver cells, A-PLO-A microcapsule-coated and B-PLO-A microcapsule-coated liver cells was studied. It was found that the chemical-free microcapsules showed no positive effect on the rats with liver failures, with a death rate of 100% in both groups 3 days after the implantation. The ALT, AST and ALB levels were all improved in the isolated liver cell group, the A-PLO-A microcapsule-coated and the B-PLO-A microcapsule-coated groups. The survival rate of both microcapsule-coated liver cell groups was significantly higher than that of the chemical-free microcapsule group and the isolated liver cells group. The microcapsules were retrieved after 4 weeks' implantation, which were observed to be smooth with no cells attaching to the surface. No apparent fibrosis was observed. This research demonstrated the physical stability and the biocompatibility of the PLO-based alginate microcapsules and therefore they could be used as liver cell carriers during implantation.

Peptidylarginine Deiminase and Citrullination: Potential Therapeutic Targets for Inflammatory Diseases

The multiple post-translational modifications of proteins display specific gain- or loss-of-function under normal and abnormal conditions. These modifications are precisely regulated by post-translational modification enzymes. The altered molecular status perturbs the pattern of gene expression and decides on a direction to signal transduction cascades as well as intrinsic properties of the proteins. Ultimately, it strictly maintains intracellular environment or results in disease manifestations. Recently, it has become that enzyme-dependent modification of arginine residue to citrulline exerts an important role in the induction of autoimmunity including rheumatoid arthritis, multiple sclerosis, and cancer. The modification of arginine residue to citrulline on proteins is called 'citrullination' or 'deimination' and is regulated by the calcium-dependent enzyme peptidylarginine deiminase (PAD). Now many effective PAD inhibitors (for example, Cl-amidine) have developed that ameliorates disease phenotypes. In this review, we discuss crucial roles of PAD enzyme and citrullination, the effectiveness of PAD inhibitors, and the implication in pathology.

Plasma free amino acid profiles of canine mammary gland tumors

The purpose of this study was to elucidate the relationship between plasma free amino acid (PFAA) levels and the clinical stages of mammary gland tumors (MGT) in dogs. PFAA levels in canines with malignant mammary tumors were decreased compared to those of healthy animals. The levels of aspartate and ornithine, in the dogs with tumor metastasis were significantly decreased when compared to those of dogs that did not have metastases. Results of this study indicate that PFAA levels could be a risk factor or biomarker for canine MGT metastasis.

Accumulation of argpyrimidine, a methylglyoxal-derived advanced glycation end product, increases apoptosis of lens epithelial cells both in vitro and in vivo

The formation of advanced glycation end products (AGEs) has been considered to be a potential causative factor of injury to lens epithelial cells (LECs). Damage of LECs is believed to contribute to cataract formation. The purpose of this study was to investigate the cytotoxic effect of AGEs on LECs both in vitro and in vivo. We examined the accumulation of argpyrimidine, a methylglyoxal-derived AGE, and the expression of apoptosis-related molecules including nuclear factor-kappaB (NF-kappaB), Bax, and Bcl-2 in the human LEC line HLE-B3 and in cataractous lenses of Zucker diabetic fatty (ZDF) rats, an animal model of type 2 diabetes. In cataractous lenses from twenty-one-week-old ZDF rats, LEC apoptosis was markedly increased, and the accumulation of argpyrimidine as well as subsequent activation of NF-kappaB in LECs were significantly enhanced. The ratio of Bax to Bcl-2 protein levels was also increased. In addition, the accumulation of argpyrimidine triggered apoptosis in methylglyoxal-treated HLE-B3 cells. However, the presence of pyridoxamine (an AGEs inhibitor) and pyrrolidine dithiocarbamate (a NF-kappaB inhibitor) prevented apoptosis in HLE-B3 cells through the inhibition of argpyrimidine formation and the blockage of NF-kappaB nuclear translocalization, respectively. These results suggest that the cellular accumulation of argpyrimidine in LECs is NF-kappaB-dependent and pro-apoptotic.

Hyperammonemia in a Patient with Late-Onset Ornithine Carbamoyltransferase Deficiency

Ornithine carbamoyltransferase (OTC) deficiency is a urea cycle disorder that causes the accumulation of ammonia, which can lead to encephalopathy. Adults presenting with hyperammonemia who are subsequently diagnosed with urea cycle disorders are rare. Herein, we report a case of a late-onset OTC deficient patient who was successfully treated with arginine, benzoate and hemodialysis. A 59-yr-old man was admitted to our hospital with progressive lethargy and confusion. Although hyperammonemia was suspected as the cause of the patient's mental changes, there was no evidence of chronic liver disease. A plasma amino acid and urine organic acid analysis revealed OTC deficiency. Despite the administration of a lactulose enema, the patient's serum ammonia level increased and he remained confused, leading us to initiate acute hemodialysis. After treatment with arginine, sodium benzoate and hemodialysis, the patient's serum ammonia level stabilized and his mental status returned to normal.

Effect of short-term ornithine alpha-ketoglutarate pretreatment on intestinal ischemia-reperfusion in rats / Efeitos do pré-tratamento em curto prazo com ornitina alfa-cetoglutarato na isquemia-reperfusão intestinal em ratos

PURPOSE: To investigate the effects of preventive enteral administration of ornithine alpha-ketoglutarate (OKG) in an ischemia-reperfusion rat model. METHODS: Sixty rats were randomized into five groups (G1-G5, n = 12). Each group was divided into two subgroups (n = 6) and treated with calcium carbonate (CaCa) or OKG by gavage. Thirty minutes later, the animals were anesthetized with xylazine 15mg + ketamine 1mg ip and subjected to laparotomy. G1-G3 rats served as controls. Rats in groups G4 and G5 were subjected to ischemia for 30 minutes. Ischemia was achieved by clamping the small intestine and its mesentery, delimiting a segment of bowel 5 cm long and 5 cm apart from the ileocecal valve. In addition, G5 rats underwent reperfusion for 30 minutes. Blood samples were collected at the end of the laparotomy (G1), after 30 minutes (G2, G4) and 60 minutes (G3, G5) to determine concentrations of metabolites (pyruvate, lactate), creatine phosphokinase (CPK), thiobarbituric acid reactive substances (TBARS) and glutathione (GSH). RESULTS: There was a significant decrease in tissue pyruvate and lactate and plasma CPK levels in OKG-treated rats at the end of reperfusion period. GSH levels did not change significantly in ischemia and reperfusion groups. However, TBARS levels increased significantly (p<0.05) in tissue samples in OKG-treated rats subjected to ischemia for 30 minutes. CONCLUSION: Short-term pretreatment with OKG before induction of I/R decreases tissue damage, increases pyruvate utilization for energy production in the Krebs cycle and does not attenuate the oxidative stress in this animal model.

OBJETIVO: Investigar os efeitos da administração enteral preventiva de ornitina alfa-cetoglutarato (OKG) em modelo de isquemia-reperfusão no rato. MÉTODOS: Sessenta ratos foram randomizados em cinco grupos (G1-G5, n=12). Cada grupo foi redistribuído em dois subgrupos (n=6) e tratado com carbonato de cálcio (CaCa) ou OKG por gavagem. Trinta minutos mais tarde, os animais foram anestesiados com xilazina 1mg+cetamina 15mg i.p. e submetidos à laparotomia. Os ratos dos grupos G4-G5 foram submetidos à isquemia por 30 minutos. A isquemia foi obtida por pinçamento do intestino delgado, delimitando um segmento com 5 cm de comprimento e distando 5 cm da válvula ileocecal. O grupo G5 foi submetido à reperfusão por 30 minutos. Amostras de sangue foram coletadas no final da laparotomia (G1), após 30 minutos (G2, G4) e 60 minutos (G3, G5) para determinação das concentrações de metabolitos (piruvato, lactato), creatinofosfoquinase (CPK), substâncias reativas ao ácido tiobarbitúrico (TBARS) e glutationa (GSH). RESULTADOS: Observou-se redução significante (p<0,05) das concentrações de piruvato e lactato, teciduais e CPK plasmático em ratos tratados com OKG, no final do período de reperfusão. Não houve alteração significante nos níveis plasmáticos e teciduais de GSH. Entretanto os níveis de TBARS aumentaram significativamente (p<0,05) em amostras de tecido de ratos tratados com OKG submetido à isquemia por 30 minutos. CONCLUSÃO: o pré-tratamento em curto prazo com OKG antes da indução da I/R diminui a lesão tecidual, aumenta a utilização de piruvato para produção de energia no ciclo de Krebs, mas não atenua o estresse oxidativo neste modelo animal.