The effect of ad libitum oral-administration of (-)catechin solution on ischemia-reperfusion-induced cell death of hippocampal CA1 in the gerbil was histologically examined. When (-)catechin solution instead of drinking water was orally administered ad libitum for 2 weeks, dose-dependent protection against neuronal death following by transient ischemia and reperfusion was observed. To evaluate the involvement of reduction of reactive-oxygen-species (ROIs) by the antioxidant activity of (-)catechin in this protection, the superoxide scavenging activity of the brain in catechin-treated gerbils was measured by ESR and spin-trapping using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). The superoxide scavenging activities of the brains obtained from catechin-treated gerbils were significantly higher than those of catechin-untreated animals. From these results, it was suggested that orally administered (-)catechin was absorbed, passed through the blood-brain barrier and that delayed neuronal death of hippocampal CA1 after ischemia-reperfusion was prevented due to its antioxidant activities.

Recently, the second mammalian chitinase, designated acidic mammalian chitinase (AMCase), has been identified in human, mouse, and cow. In contrast to the earlier identified macrophage-derived chitinase (chitotriosidase), this chitinase is richly expressed in the gastrointestinal (GI) tract, suggesting its role in digestion of chitin-containing foods as well as defense against chitin-coated microorganisms and parasites. This in situ hybridization study first revealed cellular localization of the gut-type chitinase in the mouse and chicken. In adult mice, the parotid gland, von Ebner's gland, and gastric chief cells, all of which are exocrine cells of the serous type, expressed the gut chitinase mRNA. In the chicken, oxyntico-peptic cells in glandular stomach (proventriculus) and hepatocytes expressed the chitinase mRNA. Because cattle produce the gut chitinase (chitin-binding protein b04) only in the liver, the gut chitinases in mammals and birds have three major sources of production, i.e., the salivary gland, stomach, and liver. During ontogenetic development, the expression level in the parotid gland and stomach of mice increased to the adult level before weaning, whereas in the stomach of chickens intense signals were detectable in embryos from incubation day 7.

ABSTRACT. Urinary excretion of N-acetyl-β-D-glucosaminidase (NAG) was examined in healthy dogs and dogs with urinary diseases, and its clinical usefulness as an indicator of urinary diseases was discussed. Twenty-eight healthy dogs and 20 dogs with urinary diseases were used. Urinary NAG activity was measured using p-nitrophenyl N-acetyl-β-D-glucosaminide as substrate, and expressed as units per gram of urinary creatinine (NAG index). Urinary NAG index in urine of healthy dogs was 3.2 ± 2.4 U/g, and NAG index in the dogs with chronic renal failure or lower urinary tract infection accompanied by pyelonephritis was higher than that in healthy dogs. However, the dogs with lower urinary tract infection without pyelonephritis showed normal values of NAG index. Some dogs with diabetic mellitus showed elevated values of NAG index when control of blood sugar was not successful. Increase of NAG index was observed in some dogs with pyometra before increases of BUN and serum creatinine concentration. Therefore, NAG index in urine seems to be a good indicator for urinary diseases in dogs. KEY WORDS: canine, N-acetyl-β-D-glucosaminidase (NAG), urinary disease, urine.J. Vet. Med. Sci. 64(4): 361-365, 2002 N-Acetyl-β-D-glucosaminidase (NAG; EC 3.2.1.30) is a lysosomal enzyme found predominantly in the proximal renal tubular cells. Urinary NAG activity has been reported to increase under conditions of renal pathologic damage in both humans [2,6,[8][9][10]20] and other animals [1,4,15]. Urinary NAG activity also has been proposed as a sensitive marker of the progression of renal diseases [2,6,8,9] and the rejection of renal allografts [13,21]. Its activity increases prior to abnormal changes of other renal function test results [8]. The usefulness of urinary NAG activity values in dogs with drug-induced proximal tubular damage has been reported [4]. We reported the usefulness of measurements of urinary NAG activity in cattle [14,15]. However, there is little information available about the measurement of urinary NAG activity in clinical cases of canine renal diseases.In the present study, to clarify the usefulness of measurements of urinary NAG activity, we evaluated urinary levels of NAG in healthy dogs and dogs with urinary diseases. MATERIALS AND METHODS Animals:Twenty-eight healthy dogs (18 males and 10 females, 1-8 years old) and 20 dogs with urinary diseases (10 males and 10 females, 1-17 years old ) were studied. The clinical conditions of the dogs with urinary disease are shown in Table 1, and included chronic renal failure (7 cases), lower urinary tract infection accompanied by pyelonephritis (2 cases), lower urinary tract infection without pyelonephritis (4 cases), diabetes mellitus (3 cases) and pyometra (4 cases). All of these dogs were sexually intact. Clinical diagnoses in diseased dogs were decided based on physical examinations, urinalysis, CBC, serum biochemistry, ultrasonography and radiography (plain and excretory urography).Urine preparation: Untimed, freely caught urine samples were collected from the do...

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A procedure is described for the purification of hemagglutinin-free Clostridium botulinum type C toxin. The toxin was purified approximately 1,000-fold from the original culture supernatant in an overall yield of 60% to a final specific toxicity of 4.4 x 107 minimal lethal doses/mg of protein. The toxin had a molecular weight of 141,000 and consisted of a heavy and a light chain. The molecular weights of the subunits were approximately 98,000 and 53,000. When comparing the molecular size and composition of type C toxin to that of botulinum toxins of different types, some common features may be suggested; i.e., the toxin has a molecular weight between 141,000 to 160,000 and is comprised of a heavy and a light chain linked by disulfide bonds (or bond.

ABSTRACT-The effects of exoenzyme C3 of Clostridium botulinum on Ca"-and drug-induced tension developments were investigated in j3-escin skinned smooth muscle of guinea pig ileum to test the involvement of a small G-protein in the regulation of myofilament Ca" sensitivity. C3 is known to ADP-ribosylate the rho p21 family of small G-proteins. Treatment with C3 (0.35 tug/ml, for 30 min) shifted the pCa-tension curve rightward along the Ca 21 concentration axis, indicating a decrease in Ca 21 sensitivity of the contractile elements. The inhibitory effect of C3 was not preserved after treatment with GDP(3S (1 mM), an antagonist of GTP for the binding to G-proteins. Stimulation of muscarinic receptors with carbachol (CCh, 100 ttM) shifted the pCa-tension curve leftward, indicating Ca 21 sensitization of tension development. The Ca2+-sensitizing effect of CCh was not observed after C3 treatment. When GTPrS (10 ttM), an activator of G-proteins, was applied at a plateau of tension development produced by a moderate concentration of Ca2+, further increase in tension was elicited and the effect of GTPrS was inhibited by C3 treatment. The results suggest the possible involvement of a rho p21-like small G-protein in the regulation of Ca 21 sensitivity of smooth muscle myofilaments. Keywords:Carbachol, Ca 2+-sensitization, Smooth muscle, GTP-binding protein, ContractionThe primary mechanism underlying smooth muscle contraction is phosphorylation of the 20-kD myosin light chain (MLC20) by MLC20 kinase that is activated by Ca 2+-calmodulin (1). It is well known that various receptor agonists can produce a greater tension development than high KCl solution even if cytosolic Ca 21 concentration ([Ca 2+];) is increased to the same level in intact smooth muscle (2, 3). This phenomenon was clearly demonstrated in [Ca 2+];-clamped, permeabilized smooth muscle preparations (4, 5). The greater tension development is associated with an increase in MLC20 phosphorylation (6-8), and thus an increase in the ratio of MLC20 kinase activity to MLC phosphatase activity has been suggested (9, 10). Heterotrimetric G-proteins have been suggested to serve as transmembrane signal transducers for receptors by which the Ca2+-sensitizing effect is mediated (5, 7), but signaling pathways responsible for the receptor/G-protein-mediated Ca 2+-sensitizing effect have not been clarified yet. Recent studies indicate that C3 and EDIN, exoenzymes of Clostridium botulinum and Staphylococcus aureus, respectively, selectively ADP-ribosylate the rho p21 family of a superfamily of ras p21 and its related small G-proteins (11 -13). Hirata et al. (14) found that EDIN and C3 blocked GTPTS-induced Ca 21 sensitization of tension development and caused ADP-ribosylation of a rho p21-like protein in saponin-skinned arterial smooth muscle, and they suggested involvement of a member of the rho p21 family, rho A p21, in the Ca 21 sensitization. Current knowledge suggests that it would be attractive to test the possibility that Ca" -sensitizing effects of agonists can be blo...

ABSTRACT. Mammary tumors are the most common neoplasm in female dogs, Canis canis, and in women. Mutations in human Brca2 confer an increased risk of female breast cancer. Previous studies have shown that the Brca2 tumor suppressor protein interacts with the recombinational repair protein Rad51. We cloned the full-length cDNA of the canine homologues of Brca2 and Rad51 to obtain a basis for studying their relationship with susceptibility to mammary tumors. The canine Brca2 and Rad51 cDNAs are 11 and 1.5 kb long, encoding 3,471 and 339 amino acids, respectively. The amino acid sequence of canine Brca2 showed 68% homology with the human protein, and 58% homology with a murine protein. There were highly conserved regions in the C-terminus of all three proteins, where the Rad51 interacting domain and putative nuclear localization signals are located. Comparing with the partial genomic sequence previously reported, we found possible nuclear polymorphisms in exon 11, some of which result in amino acid substitutions. On the other hand, canine Rad51 protein had extremely high homology (99%) to the human and murine proteins. Expression of both Brca2 and Rad51 was detected in the mammary gland, suggesting that these two genes interact in the canine mammary gland. KEY WORDS: Brca2, genetic instability, mammary tumor, Rad51, tumor suppressor gene.