More on Effects of Storage Time and Temperature on
Urinary Enzymes: A 1-Year Study

Matteucci, Elena; Pellegrini, Luisa; Uncini-Manganelli, C; Cecere, M; Saviozzi, Michela; Giampietro, Ottavio

doi:10.1159/000468796

Cited by 12 publications

(12 citation statements)

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“…Previous validation studies using human urine have shown NAG activity to be stable at À70 1C for a period of 1 year. 24 Urine NAG activity (U/L) was standardized to urine creatinine concentration to give the NAG index. Urine samples were excluded from analysis of proteinuria, albuminuria, and NAG index, if there was evidence of a urinary tract infection, bacteriuria, pyuria, or gross hematuria.…”

Section: Protocol For Collection and Storage Of Blood And Urine Samplesmentioning

confidence: 99%

Evaluation of Predictors of the Development of Azotemia in Cats

Jepson¹,

Brodbelt

Vallance³

et al. 2009

Veterinary Internal Medicne

128

136

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Background: Chronic kidney disease (CKD) is a common condition in geriatric cats. Diagnosis is based on the development of persistent azotemia with inadequate urine concentrating ability. Biomarkers are sought for early identification.Hypothesis: Clinical variables, urine concentrating ability, proteinuria, and N‐acetyl‐β‐d‐glucosaminidase (NAG) index will be predictive of cats at risk of developing azotemia within 12 months.Animals: Client‐owned nonazotemic geriatric (≥9 years) cats.Methods: Prospective longitudinal cohort study monitoring a population of healthy nonazotemic geriatric cats every 6 months until development of azotemia, death, or the study end point (September 30, 2007). Multivariable logistic regression analysis was used to assess baseline clinical, biochemical, and urinalysis variables, urine protein to creatinine ratio (UP/C), urine albumin to creatinine (UA/C) ratio, and urinary NAG index as predictors of development of azotemia.Results: One hundred and eighteen cats were recruited with a median age of 13 years. Ninety‐five cats (80.5%) had been followed or reached the study end point by 12 months of which 30.5% (29/95) developed azotemia. Age, systolic blood pressure, plasma creatinine concentration, urine specific gravity, UP/C, UA/C, and NAG index were significantly associated with development of azotemia in the univariable analysis (P≤ .05). However, in the multivariable analysis, only plasma creatinine concentration with either UP/C (Model 1) or UA/C (Model 2) remained significant.Conclusions and Clinical Importance: This study demonstrates a high incidence of azotemia in a population of previously healthy geriatric cats. Proteinuria at presentation was significantly associated with development of azotemia although causal association cannot be inferred. Evaluation of NAG index offered no additional benefit.

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Section: Protocol For Collection and Storage Of Blood And Urine Samplesmentioning

confidence: 99%

Evaluation of Predictors of the Development of Azotemia in Cats

Jepson¹,

Brodbelt

Vallance³

et al. 2009

Veterinary Internal Medicne

128

136

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“…Analysis of covariance (ANCOVA) models also controlled for age [17,[27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42], gender [16,17,20,22,[36][37][38][39][40][41][42][43][44][45][46], race [35][36][37][45][46][47][48][49], lean body mass, and storage time [50][51][52][53][54][55][56][57][58][59][60][61], as effects of these factors ...…”

Section: Discussionmentioning

confidence: 99%

The influence of urinary flow rate in children on excretion of markers used for assessment of renal damage: albumin, γ-glutamyl transpeptidase, N-acetyl-β-D-glucosaminidase, and alpha1-microglobulin

2007

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The aim of the present study was to examine the influence of urinary flow rate on markers of renal function in children. A sub-study of the New England Children's Amalgam Trial collected 82 pairs of urine samples from children aged 10-16 years: a timed overnight collection and a spot daytime sample collected the following day. These samples were analyzed for albumin, gamma-glutamyl transpeptidase (gamma-GT), N-acetyl-beta-D-glucosaminidase (NAG), alpha1-microglobulin (A1M), and creatinine concentration. Regression analysis was used to model the effect of urinary flow rate in the timed overnight samples. A paired t-test compared concentrations and creatinine-corrected renal markers between overnight and daytime samples. Albumin, gamma-GT, NAG, and A1M excretion rates increased significantly with urinary flow rate. Their corresponding creatinine-corrected markers did not vary significantly with urinary flow rate, but the creatinine-corrected excretions of albumin, gamma-GT, and NAG were significantly higher in daytime samples than in overnight samples, with the same (non-significant) trend for A1M. The influence of urinary flow rate on creatinine-corrected markers of renal function was markedly less than its influence on excretion rates. Therefore, the use of creatinine-corrected markers seems to be a good choice in practice, with the caveat that daytime and overnight samples are not comparable.

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“…In practice, storage at or below 4°C will slow down the degradation of sample constituents. However, loss of enzyme activity after low-temperature storage (Matteucci et al, 1991) would indicate that there are perceptible changes to the macromolecules. By and large, the effects of storage depend on the nature of chemical species and the storage conditions.…”

Section: Sample Storagementioning

confidence: 99%