Evaluation of kidney injury through early markers in canine pyometra / Avaliação de lesão renal através de marcadores precoce em piometra canina

Fourteen female dogs diagnosed with pyometra were studied at three separate times: at diagnosis (T0) and 24 h (T1) and 10-15 days (T2) after ovariohysterectomy (OH). The means of the markers, symmetric dimethylarginine (SDMA) (17.71 to 26.54 µg/dL) and the urinary gamma-glutamyl transferase to creatinine ratio (uGGT/uCr) (1.06 to 2.62 U/mg), varied, showing an increase with time. Further, the elevation of gamma-glutamyl transferase (uGGT) (56.61 to 128.12 U/L) and the urinary protein to creatinine ratio (RPC) (0.26 to 1.24) was evident at T0 and T1. A reduction in the means of RPC, uGGT, and uGGT/uCr was observed 10-15 days after OH. Despite the elevation of these markers, the concentration of creatinine (1.11 to 1.40 mg/dL), urea (40.07 to 67.16 mg/dL), and urinary specific gravity (1.027 to 1.028) only presented slight variation. In canine pyometra, complications secondary to acute renal injury may be present that may be mild and transient in most treated animals. As elevation in SDMA and RPC preceded changes in creatinine levels for the evaluation of glomerular filtration, tubular markers could assist in the early identification of renal damage in canine pyometra.(AU)

Catorze cadelas com diagnóstico de piometra foram estudadas em três tempos distintos, sendo no momento do diagnóstico (T0), 24 horas (T1) e 10 a 15 dias (T2) após a ovário-histerectomia (OH). O objetivo foi avaliar o uso de diferentes biomarcadores renais em cadelas com piometra e estimar suas precocidades diante do agravo. As médias em dimetilarginina simétrica (SDMA) (17,71 a 26,54µg/dL) e relação gama-glutamil transferase e creatinina urinária (uGGT/uCr) (1,06 a 2,62U/mg) variara, apresentando aumento em todos os momentos. Já a elevação do gama-glutamil transferase (uGGT) (56,61 a 128,12 U/L) e da razão proteína e creatinina urinárias (RPC) (0,26 a 1,24) foram evidenciadas nos dois primeiros tempos. Uma redução na média do RPC, uGGT e uGGT/uCr foi observada 10-15 dias após a implantação do tratamento (OH). Apesar da elevação desses marcadores, a concentração de creatinina (1,11 a 1,40mg/dL), ureia (40,07 a 67,16mg/dL) e densidade urinária (1,027 a 1,028) sofreram poucas variações. Em piometra canina, as complicações renais agudas secundárias podem estar presentes, ainda que leve e transitória nos animais tratados. Os marcadores tubulares foram considerados precoces na injúria renal aguda. Além disso, a SDMA e o RPC antecederam as alterações de creatinina em todos os tempos analisados.(AU)

Contribution of Ser463 residue to the enzymatic and autoprocessing activities of Escherichia coli -glutamyltranspeptidase.

A serine residue Ser463, required for proper function of E. coli -glutamyltranspeptidase (EcGGT) was identified by site-directed mutagenesis on the basis of sequence alignment of human, pig, rat, and three bacterial enzymes. Thr-, Asp-, and Lys-substituted variants were overexpressed in E. coli M15 cells and the recombinant proteins were purified to near homogeneity by nickel-chelate chromatography. With the exception of S463T, the other two variants completely lost GGT activity, implying the importance of this residue in EcGGT. Moreover, substitution of Ser463 with either Lys or Asp impaired the capability of autocatalytic processing of the precursor into - and -subunit. Computer modeling showed that the critical bonding distance of Gln390 C-Thr391 OG1 was significantly increased in S463D and S463K, indicating that these distance changes might be responsible for the lack of enzyme maturation. Measurements of intrinsic tryptophan fluorescence revealed alteration of the microenvironment of aromatic amino acid residues in S463D and S463K, while circular dichroism (CD) spectra were nearly identical for wild-type and all mutant enzymes. The temperature-dependent signal in the far-UV region for S463T was consistent with that of wild-type enzyme, but S463D and S463K showed a different sensitivity towards temperature-induced denaturation. These results implied that a significant conformational change occurred as a result of Asp- and Lys-substitution.

Comparative study on the activity of 5'-nucleotidase 5-nt and gamma glutamyl transferase [GGT] in some tissues of donkeys, calves and goats [the effect of freezing and thawing] [with one table and 2 figures]

5'-nucleotidase [5'-NT] and Gamma glutamyl transferase [GGT] activity was measured in the tissues of four 2-6 years old donkeys; four 6-9 month old castrated male goats and four 6-9 month old male calves. In donkeys the lung is the richest source of the enzyme 5'-NT, whereas in goats the liver contains a higher activity of the enzyme compared with other species. Generally the values of 5'-NT activities in tissues of calves and goats are higher than those of donkeys. GGT is mainly located in the kidneys, pancreas and liver of all the species studied. 20-25% loss in activity of GGT occurred after thawing and freezing of tissues for 2 weeks whereas more than 50% loss in activity of the enzyme occurred in four weeks period. The fall in the activity of 5'-NT in tissues was not consistent in all tissues during the first two weeks, but after four weeks period 50% loss of activity was observed