Tyrosine Ratio Research Articles

Effect of ageing and cataract formation on the Raman spectroscopic profile of human lens: An observational study.

To observe the spectroscopic profile of human lens in different age groups and varying grades of cataract and to use the data to arrive at differentiating molecular biology. An observational cross-sectional study. The study enrolled 30 patients (30 eyes) with a mean age of 59.6 years diagnosed with immature senile cataracts. The patients underwent small incision cataract surgery, and the harvested lens nuclei were examined under a Raman spectroscope for studying their molecular composition. The relative intensities of the peaks in the Raman spectra were evaluated and compared among different age groups and grades of cataract. A correlation of tyrosine doublet ratio with grade of cataract and age of the subject was calculated. Several Raman spectral peaks were observed in the range of 600 cm-1 to 1800 cm-1 with correspondence to tyrosine, phenylalanine, tryptophan, and amides I and III. A strong negative correlation between the grade of cataract and the ratio of tyrosine doublet was seen (r = -0.805). Also, a negative correlation between age and tyrosine ratio was seen (r = -0.62). The wavenumber/spectral peak of tryptophan was observed only in one sample, and amides I and III were identified, but the intensity of the peak for amide II was very small or absent. It was observed that the buried conformation of tyrosine was predominant in cases with a higher age or grade of cataract. The buried conformation of tryptophan became less in the higher grades of cataract.

Differences in branched-chain amino acid to tyrosine ratio (BTR) among etiologies of chronic liver disease progression compared to healthy adults.

The branched-chain amino acids (BCAAs) to tyrosine (Tyr) ratio (BTR) test is used to evaluate the progression of chronic liver disease (CLD). However, the differences across sex, age, body mass index (BMI) and etiologies are still unclear. We retrospectively reviewed data from 2,529 CLD cases with free amino acids (FAAs) in peripheral blood from four hospitals and 16,421 general adults with FAAs data from a biobank database. In total, 1,326 patients with CLD (covering seven etiologies) and 8,086 healthy controls (HCs) were analyzed after exclusion criteria. We investigated the change of BTR in HCs by sex, age and BMI and then compared these to patients divided by modified ALBI (mALBI) grade after propensity score matching. BTR is significantly higher in males than females regardless of age or BMI and decreases with aging in HCs. In 20 types of FAAs, 7 FAAs including BCAAs were significantly decreased, and 11 FAAs including Tyr were significantly increased by mALBI grade in total CLD. The decreasing timings of BTR were at mALBI grade 2b in all CLD etiologies compared to HCs, however in chronic hepatitis C (CHC), chronic hepatitis B (CHB) and alcoholic liver disease (ALD), BTR started to decrease at 2a. There was a positive correlation between BCAAs and albumin among parameters in BTR and mALBI. The correlation coefficients in PBC, ALD and MASLD were higher than those of other etiologies. BTR varies by sex and age even among healthy adults, and decreasing process and timing of BTR during disease progression is different among CLD etiologies.

The value of simultaneous determination of blood large neutral amino acids and tetrahydrobiopterin metabolites in the diagnosis of atypical hyperphenylalaninemia

Tetrahydrobiopterin deficiency in newborns with atypical hyperphenylalaninemia requires rapid and accurate diagnosis and the ability to distinguish it from the classical type to prevent early irreversible neurological damage. The study aimed to evaluate neopterin and biopterin (products of tetrahydrobiopterin recycling pathway) and amino acid profiles (used in supplementation therapy) in patients with hyperphenylalaninemia after optimizing ultra-performance liquid chromatography coupled with tandem mass spectrometry to simultaneously measure neopterin, biopterin, and amino acids in dried blood spots. The study enrolled preselected infants with classic (n = 46), atypical (n = 14) hyperphenylalaninemia, and a control group (n = 50).Result Tandem mass spectrometry detected neo/biopterin in the blood with a sensitivity and specificity of 100%. The mean neo/biopterin levels were significantly lower in the atypical cases (4 ± 1 and 3 ± 1 nmol/L) than the classic (49 ± 13 and 50 ± 12 nmol/L) and control (15.2 and 15.3 nmol/L) groups and correlated with phenylalanine and phenylalanine to tyrosine ratio (all P < 0.05). The study compared classic and atypical hyperphenylalaninemia cases with the control group. Both classic and atypical cases exhibited decreased levels of arginine, valine, and leucine compared to controls. Classic cases showed increased levels of citrulline, ornithine, and methionine, while atypical cases showed increased citrulline levels only. Comparing atypical versus classic cases, atypical cases exhibited decreased levels of citrulline, ornithine, methionine, arginine, leucine, and valine (all P < 0.05). Correlation analysis revealed negative associations between ornithine and biopterin and between arginine and neopterin in classic PKU cases. These findings highlight distinct metabolic differences between classic and atypical PKU.Conclusion The optimized method detected neo/biopterin in the blood with accuracy and precision. The characteristic pattern of neo/biopterin in the blood makes it possible to differentiate between classic and atypical hyperphenylalaninemia with a sensitivity and specificity of 100%. The amino acid profile could add value when treatment with large neutral amino acids is considered.

Platelets characteristics in patients with coronary artery disease and atrial fibrillation

The aim. To estimate the connections between platelet morphological characteristics and amino acids (AA) profile in patients with coronary artery disease (CAD) and atrial fibrillation (AF).&#x0D; Materials and methods. 300 patients were included in the study. They were divided into 3 groups: first (CAD) – 149 patients with CAD but without arrhythmias, second (CAD+AF) – 124 patients with CAD and AF paroxysm and control group – 27 patients without CAD and arrhythmias. Platelets AA level was detected by method of ion exchange liquid column chromatography. Total platelet count (PC), mean platelet volume (MPV), platelets distribution width (PDW), platelet-to-leukocyte (PLR) were obtained from common blood count.&#x0D; Results. Significant decline of PC and rise of MPV and PLR ratio was found in CAD patients and AF paroxysm in comparison with group with CAD without arrhythmia, p &lt; 0.05. Significant increase of isoleucine, leucine and decrease of threonine, serine, glycine, valine levels was found, changes in branched chain amino acids (rise of Isoleucine + Leucine / Valine ratio) and Glycine + Serine (decline Glycine + Serine sum) metabolism were revealed in CAD patients and AF paroxysm in comparison with group with CAD without arrhythmia, p &lt; 0.05. Phenylalanine / Tyrosine ratio was significantly elevated in CAD patients with and without AF, p &lt; 0.05.&#x0D; Taurine, serine, and glycine correlated with platelets morphological characteristics: PC (r = 0.714, r = 0.732 and r = 0.340 consequently), MPV (r = -0.724, r = -0.390 and r = -0.571 consequently), PDW (r = -0.666 and r = -0.364 consequently) and PLR (r = 0.586 and r = 0.648 consequently), p &lt; 0.05. Platelets glycine (AUC = 0.8760), valine (AUC = 0.8707), leucine (AUC = 0.8267) and threonine (AUC = 0.8213) levels are closely connected with AF paroxysm in CAD patients by ROC-analysis results, p &lt; 0.05.&#x0D; Platelets amino acids combinations: Glycine + 0.6 × Valine (AUC = 0.9987), Threonine – 3.6 × Leucine (AUC = 0.9040) were found in prediction AF paroxysm for CAD patients by ROC-analysis results, p &lt; 0.05.&#x0D; Conclusions. Connections between platelets morphology and AA profile violations in patients with CAD and AF paroxysm were found in our study.

Persistent Symptoms and IFN-γ-Mediated Pathways after COVID-19.

After COVID-19, patients have reported various complaints such as fatigue, neurological symptoms, and insomnia. Immune-mediated changes in amino acid metabolism might contribute to the development of these symptoms. Patients who had had acute, PCR-confirmed COVID-19 infection about 60 days earlier were recruited within the scope of the prospective CovILD study. We determined the inflammatory parameters and alterations in tryptophan and phenylalanine metabolism in 142 patients cross-sectionally. Symptom persistence (pain, gastrointestinal symptoms, anosmia, sleep disturbance, and neurological symptoms) and patients' physical levels of functioning were recorded. Symptoms improved in many patients after acute COVID-19 (n = 73, 51.4%). Still, a high percentage of patients had complaints, and women were affected more often. In many patients, ongoing immune activation (as indicated by high neopterin and CRP concentrations) and enhanced tryptophan catabolism were found. A higher phenylalanine to tyrosine ratio (Phe/Tyr) was found in women with a lower level of functioning. Patients who reported improvements in pain had lower Phe/Tyr ratios, while patients with improved gastrointestinal symptoms presented with higher tryptophan and kynurenine values. Our results suggest that women have persistent symptoms after COVID-19 more often than men. In addition, the physical level of functioning and the improvements in certain symptoms appear to be associated with immune-mediated changes in amino acid metabolism.

Effects of Dietary Phenylalanine: Tyrosine Ratio on Growth, DNA/RNA, Serum Biochemistry, Digestive Enzyme Activities and Physiological Responses of Heteropneustes fossilis

Stinging catfish (Heteropneustes fossilis) has high consumer demand due to its high iron and calcium contents. Also, being a lean fish, it is very suitable for people who do not prefer to consume animal fats. In view of its nutritional and therapeutic significance and lack of data on dietary phenylalanine: tyrosine ratio, a dose-response experiment was conducted to determine phe: tyr ratio for H. fossilis fry (4.1±0.3g). Six isonitrogenous (380 g/kg crude protein) and isocaloric (15.3 kJ/g digestible energy) amino acid test diets were prepared by adjusting 26.6 g/kg of total phenylalanine and tyrosine in varying ratios of phenylalanine/tyrosine (30:70, 40:60, 50:50, 60:40, 70:30, 80:20) on molar basis. Quadruplicate groups of fishes were fed with diets indicated for 12-weeks to apparent satiation, thrice daily. Mathematical analyses of Daily Growth Coefficient (DGC%), Specific Growth Rate (SGR%/day), Feed Conversion Ratio (FCR) and Erythrocyte Osmotic Fragility (EOF) as quadratic-broken line regression analyses, exhibited optimum dietary phenylalanine: tyrosine ratio of 64.94: 35.06 corresponding to 15.83 g/kg: 8.55 g/kg on equimolar basis. Data of this study would be of high significance to ensure that optimum phenylalanine and tyrosine ratio of fish is met while using a greater variety of cost-effective dietary protein feedstuffs for sustainable aquafarming of this fish.

Micro-Raman spectroscopy study of blood samples from myocardial infarction patients

Acute myocardial infarction (MI) is found to be a major causative factor for global mortality and morbidity. This situation demands necessity of developing efficient and rapid diagnostic tools to detect acute MI. Raman spectroscopy is a non-destructive optical diagnostic technique, which has high potential in probing biochemical changes in clinical samples during initiation and progress of diseases. In this work, blood was taken as the sample to examine inflammation in acute MI patients using Raman spectroscopy. Ratio of Raman peak intensities that corresponds to phenylalanine (1000 cm−1) and tyrosine (825 cm−1) can facilitate indirect information about tetrahydrobiopterin (BH4) availability, which can indicate inflammatory status in patients. This ratio obtained was higher for MI patients in comparison with control subjects. The decrease in phenylalanine and tyrosine ratio (Phe-Tyr ratio) is attributed to the prognosis of standard of care (medications like antiplatelets including aspirin, statin and revascularisation) leading to inflammation reduction. Phe-Tyr ratio estimated from the Raman spectra of blood can be exploited as a reliable method to probe inflammation due to MI. The method is highly objective, require only microliters of sample and minimal sample preparation, signifying its clinical utility.

Serum Amino Acid Profiles Predict the Development of Hepatocellular Carcinoma in Patients with Chronic HBV Infection.

Background: The study aimed to find out the alterations in serum amino acid (AA) profiles and to detect their relationship with carcinoma formation. Methods: Targeted metabolomics based on ultraperformance liquid chromatography triple quadrupole mass spectrometry to quantitatively analyze serum AA levels in 136 hepatitis B (CHB) patients and 93 hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) patients. Results: It was shown that decreased serum levels of leucine, lysine, threonine, tryptophan, valine, serotonin, and taurine were observed in more HCC patients than CHB patients, but the serum phenylalanine level was increased. Serum valine and serotonin were lower in Class C than Class A and Class B in HCC patients. Accompanied with the higher score of Model for End-Stage Liver Disease, serum phenylalanine was increased not only in CHB patients but also in HCC patients. The serum level of phenylalanine increased in the decompensated stage more than in the compensated stage, while serum leucine and serotonin significantly decreased. Serum serotonin still had significant differences between CHB and HCC both in the HBV desoxyribonucleic acid (HBV-DNA) negative group and in the HBV-DNA positive group. Furthermore, it was shown that the tryptophan ratio, branched-chain amino acids (BCAA)/aromatic amino acids ratio, BCAAs/tyrosine ratio, Fischer’s ratio, and serotonin-to-tryptophan ratio significantly decreased, while the tyrosine ratio and the kynurenine-to-tryptophan ratio increased in HCC patients more than those in CHB. Conclusions: A distinct metabolite signature of some specific serum amino acids was found between CHB and HCC patients, which may help predict the development of HCC at an early stage.

Exploring Early Detection of Frailty Syndrome in Older Adults: Evaluation of Oxi-Immune Markers, Clinical Parameters and Modifiable Risk Factors.

Ageing is accompanied with a decline in several physiological systems. Frailty is an age-related syndrome correlated to the loss of homeostasis and increased vulnerability to stressors, which is associated with increase in the risk of disability, comorbidity, hospitalisation, and death in older adults. The aim of this study was to understand the relationship between frailty syndrome, immune activation, and oxidative stress. Serum concentrations of vitamins A and E were also evaluated, as well as inflammatory biomarkers (CRP and IL-6) and oxidative DNA levels. A group of Portuguese older adults (≥65 years old) was engaged in this study and classified according to Fried’s frailty phenotype. Significant increases in the inflammatory mediators (CRP and IL-6), neopterin levels, kynurenine to tryptophan ratio (Kyn/Trp), and phenylalanine to tyrosine ratio (Phe/Tyr), and significant decreases in Trp and Tyr concentrations were observed in the presence of frailty. IL-6, neopterin, and Kyn/Trp showed potential as predictable biomarkers of frailty syndrome. Several clinical parameters such as nutrition, dependency scales, and polypharmacy were related to frailty and, consequently, may influence the associations observed. Results obtained show a progressive immune activation and production of pro-inflammatory molecules in the presence of frailty, agreeing with the inflammageing model. Future research should include different dimensions of frailty, including psychological, social, biological, and environmental factors.

Application of Raman spectroscopy in a correlation study between protein oxidation/denaturation and conformational changes in beef after repeated freeze–thaw

AbstractKnowledge of protein properties is vital for quality assessment in meat systems. This study applied Raman spectroscopy to investigate the relationship between protein oxidation/denaturation and conformational changes in beef during repeated freeze–thaw (RFT). A lower α‐helix and higher β‐sheet content was observed after RFT. The I850 cm−1/I830 cm−1 intensity ratio of tyrosine indicates that tyrosine residues were exposed to the polar environment during RFT. Further, RFT led to increased carbonyl content and surface hydrophobicity, with decreased total sulphydryl content, Ca2+‐ATPase activity and enthalpy of myosin (ΔH1). Subsequently, correlation analysis showed that carbonyl content, Ca2+‐ATPase activity and ΔH1 in beef protein have good correlations with secondary protein structure data, especially ΔH1, which has a strong negative correlation (r = −0.906) with the β‐sheet/α‐helix ratio. Therefore, protein secondary conformation information during RFT has the potential to be used as a parameter for studying the thermal properties of myosin.

A Retrospective Case Series Analysis of the Relationship Between Phenylalanine: Tyrosine Ratio and Cerebral Glucose Metabolism in Classical Phenylketonuria and Hyperphenylalaninemia.

We retrospectively examined the relationship between blood biomarkers, in particular the historical mean phenylalanine to tyrosine (Phe:Tyr) ratio, and cerebral glucose metabolism. We hypothesized that the historical mean Phe:Tyr ratio would be more predictive of cerebral glucose metabolism than the phenylalanine (Phe) level alone. We performed a retrospective case series analysis involving 11 adult classical phenylketonuria/hyperphenylalaninemia patients under the care of an Inherited Metabolic & Neuropsychiatry Clinic who had complained of memory problems, collating casenote data from blood biochemistry, and clinical [18F]fluorodeoxyglucose positron emission tomography ([18F]FDG PET). The Phe:Tyr ratio was calculated for individual blood samples and summarized as historical mean Phe:Tyr ratio (Phe:Tyr) and historical standard deviation in Phe:Tyr ratio (SD-Phe:Tyr), for each patient. Visual analyses of [18F]FDG PET revealed heterogeneous patterns of glucose hypometabolism for eight patients. [18F]FDG PET standardized uptake was negatively correlated with Phe in a large cluster with peak localized to right superior parietal gyrus. Even larger clusters of negative correlation that encompassed most of the brain, with frontal peaks, were observed with Phe:Tyr, and SD-Phe:Tyr. Our case series analysis provides further evidence for the association between blood biomarkers, and cerebral glucose hypometabolism. Mean historical blood Phe:Tyr ratio, and its standard deviation over time, appear to be more indicative of global cerebral glucose metabolism in patients with memory problems than Phe.

Easy clinical predictor for low BCAA to tyrosine ratio in chronic liver disease patients with hepatocellular carcinoma: Usefulness of ALBI score as nutritional prognostic marker.

Background/AimLow branched‐chain amino acid (BCAA) to tyrosine ratio (BTR) is known as an indicator of amino acid imbalance. We elucidated usefulness of newly developed albumin–bilirubin (ALBI) score as alternative methods of BTR in patients with naïve hepatocellular carcinoma (HCC) retrospectively.Materials/MethodsIn 842 patients with HCC and without BCAA supplementation (71 years, male 614, Child‐Pugh A:B:C = 689:116:37), relationships among BTR and clinical features were evaluated. Of those, 438 patients, with Milan criteria HCC, treated curatively were divided into the high‐BTR (>4.4) (n = 293) and low‐BTR (≤4.4) (n = 145) groups. The prognostic value of BTR was evaluated using inverse probability weighting (IPW) with propensity score.ResultsThe low‐BTR group showed worse prognosis than the other (3‐, 5‐, 10‐year overall survival rates: 88.9% vs. 86.3%/70.5% vs. 78.1%/38.1% vs. 52.3%, respectively; p < 0.001). Multivariate Cox‐hazard analysis adjusted for IPW showed elderly (≥65 years) HR 2.314, p = 0.001), female gender (HR 0.422, p < 0.001), ECOG PS ≥2 (HR 3.032, p = 0.002), low platelet count (HR 1.757, p = 0.010), and low BTR (≤4.4) (HR 1.852, p = 0.005) to be significant prognostic factors. Both serum albumin level (r = 0.370, p < 0.001) and ALBI score (r = −0.389, p < 0.001) showed a significant relationship with BTR. Child‐Pugh class B, modified ALBI grade (mALBI) 2a, and mALBI 2b predictive values for BTR were 3.589, 4.509, and 4.155 (AUC range: 0.735–0.770), respectively, while the predictive value of ALBI score for low‐BTR (≤4.4) was −2.588 (AUC 0.790).ConclusionALBI score −2.588 was a predictor for low‐BTR (≤4.4), which was prognostic factors for early HCC patients, and at least patients with mALBI 2b might have an amino acid imbalance.

Significance of serum branched-chain amino acid to tyrosine ratio measurement in athletes with high skeletal muscle mass

BackgroundFew nutritional markers reflect the hypermetabolic state of athletes with high levels of skeletal muscle. Although branched-chain amino acids (BCAA) play crucial roles in protein metabolism in skeletal muscle, the relationship between skeletal muscle mass and amino acid imbalances caused by the metabolism of BCAA and aromatic amino acids remains unclear. The aim of this study is to test the hypothesis that athletes with high levels of skeletal muscle mass have plasma amino acid imbalances, assessed by serum BCAA to tyrosine ratio (BTR) which can be measured conveniently.MethodsThe study enrolled 111 young Japanese men: 70 wrestling athletes and 41 controls. None of them were under any medications, extreme dietary restrictions or intense exercise regimens. Each participant’s body composition, serum concentrations of albumin and rapid turnover proteins including transthyretin and transferrin, BTR, and thyroid function were assessed.ResultsCompared to the controls, the athletes had significantly higher skeletal muscle index (SMI) (p < 0.001), and lower serum albumin concentration (p < 0.001) and BTR (p < 0.001). Kruskal–Wallis tests showed that serum albumin concentration and BTR were significantly lower in the participants with higher SMI. Serum albumin concentration and BTR were inversely correlated with SMI by multiple regression analysis (logarithmic albumin, β = − 0.358, p < 0.001; BTR, β = − 0.299, p = 0.001). SMI was inversely and transthyretin was positively correlated with serum albumin (SMI, β = − 0.554, p < 0.001; transthyretin, β = 0.379, p < 0.001). Serum concentration of free 3,5,3′-triiodothyronine (FT3) was inversely correlated with BTR, and, along with SMI and albumin, was independent predictor of BTR (SMI, β = − 0.321, p < 0.001; FT3, β = − 0.253, p = 0.001; logarithmic albumin, β = 0.261, p = 0.003). However, FT3 was not correlated with SMI or serum albumin. Serum concentrations of rapid turnover proteins were not correlated with BTR.ConclusionsIncreased skeletal muscle mass enhances the circulating amino acid imbalances, and is independently facilitated by thyroid hormones. Serum BTR may be a useful biomarker to assess the hypermetabolic state of wrestling athletes with high levels of skeletal muscle.

Targeted Metabolomics Identifies Differential Serum and Liver Amino Acids Biomarkers in Rats with Alcoholic Liver Disease.

To investigate changes in serum and hepatic levels of amino acids in ALD and to provide novel evidence and approaches for the prevention and treatment of ALD. Twenty specific pathogen-free SD male rats were devided into two groups, ten for the control group, and ten for the model group. Serum biochemical markers, including alanine aminotransferase, aspartate aminotransferase, laminin and hyaluronidase were measured. Histological analysis of liver tissues was performed. Serum and liver amino acids levels were quantitatively determined by ultra-high-performance liquid chromatography-tandem quadrupole mass spectrometry (UPLC-TQMS)-based targeted metabolomics. Compared with the normal group, ALD rats showed an obvious increase in the levels of β-alanine, alanine, serine, ornithine, tyrosine and the tyrosine ratio, while there was a decrease in arginine levels, the BTR ratio and Fischer's ratio in serum. Additionally, ALD rats exhibited a significant increase in the levels of cysteine and putrescine, while there was a decrease in sarcosine, β-alanine, serine, proline, valine, threonine, ornithine, lysine, histidine, tyrosine, symmetric dimethylarginine, methionine, isoleucine and methionine-sulfoxide levels in liver tissues compared with the normal group. The serum and liver amino acids showed significant changes in ALD rats and can be considered as potential specific diagnostic biomarkers for ALD.

Branched-chain amino acid to tyrosine ratio is an essential pre-treatment factor for maintaining sufficient treatment intensity of lenvatinib in patients with hepatocellular carcinoma.

Lenvatinib was recently approved as a novel agent for hepatocellular carcinoma. To maximize the therapeutic effect of anticancer drugs, it is essential to maintain treatment intensity by avoiding dose reduction or discontinuation. We aimed to identify essential factors contributing to achieve sufficient treatment intensity of lenvatinib. Seventy-one patients who received treatment with lenvatinib were included in this study. We used the delivered dose intensity/body surface area ratio (DBR) to measure treatment intensity of lenvatinib. 2M-DBR (DBR for the first 60days) of lenvatinib (≥206.7) was strongly correlated with objective response and was the significant factor contributing to prolonged progression-free survival (PFS). Patients with high 2M-DBR had significantly prolonged PFS compared with those who had low 2M-DBR (P<.001). Multivariate analysis revealed that pre-treatment α-fetoprotein and branched-chain amino acid to tyrosine ratio (BTR) were significant factors in maintaining high 2M-DBR of lenvatinib. Furthermore, patients with high pre-treatment BTR (≥4.50) showed significantly longer PFS than those with low BTR (P=.032). Maintaining high 2M-DBR of lenvatinib is essential to increase response rate and PFS. To achieve high 2M-DBR levels, preservation of pre-treatment BTR is essential, suggesting the importance of nutritional management in the treatment for hepatocellular carcinoma with lenvatinib.

Role of aromatic amino acids in pathogeneses of diabetic nephropathy in Chinese patients with type 2 diabetes

BackgroundWe aimed to estimate the associations between aromatic amino acids (AAAs) and diabetic nephropathy (DN) in patients with type 2 diabetes (T2D). MethodsWe collected clinical and metabolomic data from 132 healthy subjects (HS group), 132 type 2 diabetes patients without diabetic nephropathy (T2D group) and 132 diabetic nephropathy patients (DN group) in tertiary hospital from May 2015 to August 2016. The odds ratio (OR) and 95% confidence interval (CI) were obtained by logistic regression. ResultsThe odds ratio of tyrosine for DN increased gradually. High tyrosine was associated with an increased OR of DN (model 3, OR:0.329, 95%CI, 0.144–0.750) when comparing extreme quantiles. ConclusionIn Chinese patients with T2D, elevated tyrosine was associated with increased risk of DN.

Effects of Varied Tyrosine Concentrations on FEEM and SFS of Constant Tryptophan concentration

In recent years, the 3D fluorescence excitation emission spectrum has been widely applied into the analysis of the properties of soluble organic matter in water bodies, but there is very little research on the fluorescence properties of protein residues in water quality detection by Fluorescence Excitation Emission Matrix (FEEM), and synchronous fluorescence excitation emission spectra (SFS). The characteristics of luminescent of amino acids, including tryptophan, tyrosine and phenylalanine, where tryptophan and tyrosine fluorescence are relatively strongest, and the effects of tyrosine on the fluorescence properties of tryptophan are seldom discussed in different mixing ratios for both amino acids. The fluorescent peak positions and intensities of the three amino acids are related to the angle size of conjugate plane, N hybrids and hydroxyls on benzene rings. When the ratio of tyrosine to tryptophan content is less than 150:100, tryptophan will quench the fluorescent peak of the tyrosine. Constant tryptophan content, tyrosine at excitation wavelength of 228 nm, its concentration changes with the corresponding fluorescence intensity has a good linear relationship; however, at 276-278 nm of tyrosine, the varied concentrations and fluorescence intensities are opposite.

Randomized clinical trial of the effect of intraoperative humidified carbon dioxide insufflation in open laparotomy for colorectal resection.

BackgroundAnimal studies have shown that peritoneal injury can be minimized by insufflating the abdominal cavity with warm humidified carbon dioxide gas.MethodsA single‐blind RCT was performed at a tertiary colorectal unit. Inclusion criteria were patient aged 18 years and over undergoing open elective surgery. The intervention group received warmed (37°C), humidified (98 per cent relative humidity) carbon dioxide (WHCO2 group). Multiple markers of peritoneal inflammation and oxidative damage were used to compare groups, including cytokines and chemokines, apoptosis, the 3‐chlorotyrosine/native tyrosine ratio, and light microscopy on peritoneal biopsies at the start (T0) and end (Tend) of the operation. Postoperative clinical outcomes were compared between the groups.ResultsOf 40 patients enrolled, 20 in the WHCO2 group and 19 in the control group were available for analysis. A significant log(Tend/T0) difference between control and WHCO2 groups was documented for interleukin (IL) 2 (5·3 versus 2·8 respectively; P = 0·028) and IL‐4 (3·5 versus 2·0; P = 0·041), whereas apoptosis assays documented no significant change in caspase activity, and similar apoptosis rates were documented along the peritoneal edge in both groups. The 3‐chlorotyrosine/tyrosine ratio had increased at Tend by 1·1‐fold in the WHCO2 group and by 3·1‐fold in the control group. Under light microscopy, peritoneum was visible in 11 of 19 samples from the control group and in 19 of 20 samples from the WHCO2 group (P = 0·006). The only difference in clinical outcomes between intervention and control groups was the number of days to passage of flatus (2·5 versus 5·0 days respectively; P = 0·008).ConclusionThe use of warmed, humidified carbon dioxide appears to reduce some markers related to peritoneal oxidative damage during laparotomy. No difference was observed in clinical outcomes, but the study was underpowered for analysis of surgical results. Registration number: NCT02975947 ( http://www.clinicaltrials.gov/).

Evaluation of treatment with zinc acetate hydrate in patients with liver cirrhosis complicated by zinc deficiency.

In Japan, no zinc preparation had been approved for therapeutic purposes before March 2017. Zinc acetate hydrate was recently approved for the treatment of hypozincemia. We evaluated the efficacy and safety of treatment with zinc acetate hydrate. A total of 97 patients with cirrhosis complicated by hypozincemia were treated with zinc acetate hydrate, and their serum zinc normalization rates; factors contributing to normalization; changes in blood ammonia levels; branched-chain amino acids-to-tyrosine ratios; levels of albumin, hemoglobin, alkaline phosphatase, serum copper, and iron; incidence of adverse events; improvement in subjective symptoms; and serum zinc levels taken at 3months post-treatment were determined. The cumulative serum zinc normalization rates, when normalization was defined as achievement of a serum zinc level ≥80μg/dL, after 2, 4, and 6months of treatment were 64.9%, 80.3%, and 82.5%, respectively. Multivariate analysis identified an albumin level of ≥3.3g/dL and branched-chain amino acids to tyrosine ratio of ≥3.46 as factors contributing to zinc normalization within 3months of treatment. Treatment resulted in a significant decrease in blood ammonia and serum copper levels, and significant increases in branched-chain amino acids-to-tyrosine ratios and alkaline phosphatase levels. Seven (7.2%) patients prematurely discontinued treatment due to hypocupremia. By the end of treatment, subjective symptoms had resolved in 46.2% of patients. By 3months post-treatment, serum zinc levels had reverted to levels close to those at baseline. Treatment with zinc acetate hydrate resulted in normalization of serum zinc levels at a high rate. The main reasons for discontinuation of treatment included hypocupremia.

No Influence of Low-, Medium-, or High-Dose Tyrosine on Exercise in a Warm Environment.

Tyrosine administration may counter exercise fatigue in a warm environment, but the typical dose is inconclusive, with little known about higher doses. We explored how three tyrosine doses influenced the circulating ratio of tyrosine/amino acids competing for brain uptake and hypothesized that a medium and high dose would enhance exercise performance in a warm environment. Eight recreationally trained, non-heat-acclimated male individuals (mean ± SD age, 23 ± 4 yr; stature, 181 ± 7 cm; body mass, 76.1 ± 5.9 kg; peak oxygen uptake, 4.1 ± 0.5 L·min) performed a peak oxygen uptake test, two familiarization trials, then four experimental trials in a randomized order separated by 7 d. Before exercise, subjects drank 2 × 300 mL sugar-free drinks delivering 0 (PLA), 150 (LOW), 300 (MED), or 400 (HIGH) mg·kg body mass tyrosine in a double-blind fashion. Subjects performed a 60-min constant intensity cycling then a simulated time trial in 30°C and 60% relative humidity. Time trial performance (P = 0.579) was not influenced by tyrosine ingestion. The plasma ratio of tyrosine/∑(free-tryptophan, leucine, isoleucine, valine, phenylalanine, methionine), a key determinant of brain tyrosine influx, increased relative to PLA (P < 0.001). The increase was similar (P > 0.05) in MED (7.7-fold) and HIGH (8.2-fold), and greater than that in LOW (5.3-fold; P < 0.05). No differences existed between trials in core and skin temperature, heart rate, RPE, or thermal sensation (P > 0.05). Exercise performance in a warm environment was not influenced by tyrosine availability in recreationally trained male individuals. The results provide novel data informing future studies, on the tyrosine dose maximizing the circulating ratio of tyrosine/amino acids competing for brain uptake.