Urinary felinine excretion in intact male cats is increased by dietary cystine

Felinine is a branched-chain sulfur amino acid present in the urine of certain Felidae, including domestic cats. The objective of the present study was to determine if additional cystine and/or dietary N would increase felinine and N-acetylfelinine excretion by intact male cats fed a low-protein (LP) diet. Feeding five adult intact male cats an LP diet (18·8% of metabolisable energy (ME) as protein) v. a high-protein diet (38·6% of ME as protein) resulted in a trend (P¼0·08) for decreased urinary felinine and no change in N-acetylfelinine excretion. In a 23 d study, when the LP diet was supplemented with L-cystine at 9·3 g/kg DM, urinary felinine:creatinine ratio showed a linear two-fold (121 %) increase (P,0·01) from 0·24 (SEM 0·05) to 0·53 (SEM 0·13) after 10 d. Subsequent feeding of the LP diet resulted in a decrease in felinine excretion to base levels. Plasma gglutamylfelinylglycine concentrations were consistent with the excretion of felinine. Supplementation of the LP diet with L-cystine (9·3 g/kg DM), dispensable amino acids and arginine to a second group (n 5) also resulted in a significant (P,0·01) but smaller (þ72 %) increase in the daily felinine:creatinine ratio (0·25 (SEM 0·04) to 0·43 (SEM 0·05)). The degree of felinine N-acetylation within groups was unaffected by dietary addition and withdrawal of amino acids. The results indicate that felinine synthesis is regulated by cystine availability, and that arginine may be physiologically important in decreasing felinine biosynthesis in intact male cats

the potential for enhancement of immunity in cats by dietary supplementation

This study was conducted to examine the potential benefits of dietary supplementation on the feline immune system. Forty three cats (8 or 9 per group) were fed a low protein control diet (22.7% DM basis), the same diet supplemented with yeast-derived nucleotides, salmon oil or l-arginine or a commercial moist high protein diet (53.0% DM basis) for a period of five weeks. The low protein diets were formulated using a commercial moist diet base with added fat and starch and fed ad libitum, along with water. Specific immune assays showed that supplementation with arginine caused a significant enhancement of lymphocyte proliferative responses to the T-cell mitogen PHA after 35 days (P = 0.018), while supplementation with either nucleotides or salmon oil resulted in significant enhancement after both 14 (P = 0.0048, P <0.0001 respectively) and 35 days (both P <0.0001). Dietary supplementation with arginine, nucleotides or salmon oil each led to significant increases in blood leucocyte phagocytic activity after both 14 (P = 0.0003, P = 0.0077, P <0.0001 respectively) and 35 days (P <0.0001). This indicates that a number of dietary ingredients have the ability to modulate the immune system of healthy cats possibly resulting in a greater ability to fight infection and diseas

Testosterone increases urinary free felinine, N-acetylfelinine and methylbutanolglutathione excretion in cats (Felis catus)

Two days after castration, urinary free felinine plus N-acetylfelinine decreased 24% in male cats, but, by day 5, the concentration had not decreased to that routinely found in males that have been castrated for several months. In a second experiment, three groups of castrated adult male cats received different subcutaneous injections: control (carrier), testosterone, testosterone plus estradiol. A fourth group of intact adult female cats received a testosterone injection. Urine was collected and analysed for free felinine, N-acetylfelinine and 3-methylbutanolglutathione. Baseline blood testosterone and estradiol concentrations were low during the pre-period, but increased sharply after hormone injections. The concentration of all three urinary metabolites increased as a result of testosterone injections with estradiol not modulating the effect. The effect of testosterone was not gender dependent. The concentration of free felinine, N-acetylfelinine and 3-methylbutanolglutathione in the urine remained low in the placebo control group throughout the study. The relative molar contribution of free felinine to the total amount of felinine containing compounds increased due to testosterone treatment, while the contribution of 3-methylbutanolglutathione and N-acetylfelinine decreased. Testosterone increases free felinine, N-acetylfelinine and 3-methylbutanolglutathione excretion in castrated adult male and intact female cats, whereas estradiol does not modulate this effect

Relationship between lower limb vascular characteristics, peripheral arterial disease and gait in rheumatoid arthritis

Objectives: Rheumatoid arthritis (RA) is associated with higher risk of atherosclerotic vascular disease, including peripheral arterial disease (PAD). The aim of this study was to measure lower limb vascular characteristics (indicative of PAD), using non-invasive chairside testing methods, in people with RA compared to matched controls, and to determine the association between vascular characteristics and gait velocity as a measure of functional capacity in people with RA. Methods: This was a cross-sectional pilot study which measured lower limb vascular characteristics (bilateral continuous wave Doppler, toe brachial index [TBI] and ankle brachial index [ABI]) and gait velocity (6-m walk test) in people with RA and controls. Differences in vascular characteristics between groups were determined using linear regression models, and associations between vascular characteristics and gait were determined using logistic regression models. Results: Seventy-two participants were included: 34 participants with RA mean disease duration 26.2 (SD 12.1) and 38 age- and sex-matched controls. The control group contained 30 females (79%), and the RA group had 28 females (82%). There were no significant differences between the RA and control groups for lower limb vascular characteristics. People with RA walked significantly slower compared to controls (1.10 m/s vs 0.91 m/s, P <.001). People with RA who had abnormal TBI, or abnormal qualitative Doppler walked significantly slower compared to those with normal TBI (0.86 m/s vs 0.95 m/s, P =.043 and 0.81 m/s, vs 0.93 m/s, P =.028). There was no significant association between ABI and gait velocity. Conclusion: This study did not identify different lower limb vascular characteristics in people with RA compared to matched controls. However, in people with RA, abnormal Doppler and TBI results are associated with slower walking velocity

Amino Acid Analysis

Amino acid analysis is used to determine the amino acid content of amino acid–, peptide- and protein-containing samples. With minor exceptions, proteins are long linear polymers of amino acids connected to each other via peptide bonds. The first step of amino acid analysis involves hydrolyzing these peptide bonds. The liberated amino acids are then separated, detected, and quantified. The method was first developed by Moore, Stein and coworkers in the 1950s using HCl acid hydrolysis, and, despite considerable effort by many workers, the basic methodology remains relatively unchanged. This unit provides an overview and strategic planning for amino acid analysis, discussing a range of methodologies and issues. In addition, several common methods used for analysis of l-amino acids are described in detail, including: HCl acid hydrolysis, performic acid oxidation for methionine and cysteine analysis, base hydrolysis for tryptophan analysis, analysis of free amino acids, and analysis of reactive lysine