Post-prandial serum bile acid concentrations and ammonia tolerance in Maltese dogs with and without hepatic vascular anomalies

SUMMARY: Post-prandial serum bile acid concentrations were measured in 200 Maltese dogs in an attempt to identify those with subclinical portosystemic shunts. Five of these were later shown to have hepatic pathology or abnormal liver function. In the other 195 Maltese bile acid concentrations ranged from 1 to 362 μmol.L^-1 (mean ± SD, 70 ±50 μmol.L^-1; median, 65.0 μmol.L^-1). Of these, 79% were above the reference range (0 to 31 μmol.L^-1) established from 23 mixed-breed control dogs. It was therefore not possible to determine the prevalence of subclinical portosystemic shunts on the basis of bile acid determinations.
Further investigation of liver function was performed to investigate why bile acid concentrations were increased in these dogs. Rectal ammonia tolerance tests were normal in 102 of 106 Maltese tested and liver samples (11 dogs) and plasma biochemistry profiles (9 dogs) demonstrated no significant hepatic disease or dysfunction.
Of 2 Maltese with hyperammonaemia after administration of ammonium chloride, one had a large congenital portosystemic shunt that was confirmed at surgery. In the other there were no macroscopic portosystemic communications, but a liver biopsy showed histological changes consistent with microscopic portovascular dysplasia.
Total serum bile acid concentrations were consistently lower when assessed by highperformance liquid chromatography than by an enzymatic spectrophotometric method. This discrepancy was substantially larger in Maltese than in control dogs, suggesting the presence of an additional reacting substance in the serum of Maltese dogs.     

Glomerulopathy in dogs with congenital portosystemic shunts

Kidney specimens from 12 dogs with congenital portosystemic shunts were examined histologically. Glomerulopathy of variable severity was present in the kidney sections of all 12. Marked irregular thickening of the glomerular capillary wall was the most prominent pathological change, the renal interstitium being largely unaffected. The severity of lesions was not correlated with the age of dogs at the time of necropsy. An immunoperoxidase technique failed to demonstrate significant IgA or IgG deposition in affected glomeruli. Proteinuria was generally mild or absent despite significant glomerular lesions, except in dogs with concurrent urinary tract infection.     

Congenital Interruption of the Portal Vein and Caudal Vena Cava in Dogs: Six Case Reports and a Review of the Literature

Objective —To describe six dogs with congenital abnormalities involving the portal vein, caudal vena cava, or both.
Animals —Six client-owned dogs with congenital interruption of the portal vein or the caudal vena cava, or both.
Methods —Portal vein and caudal vena cava anatomy was evaluated by contrast radiography and visualization at surgery. Vascular casts or plastinated specimens were obtained in three animals.
Results —Portal blood shunted into the caudal vena cava in four dogs and the left hepatic vein in one. Two of these five dogs also had interruption of the caudal vena cava with continuation as azygous vein, as did an additional dog, in which the portal vein was normally formed. Portal vein interruption was present in 5 of 74 (6.8%) dogs with congenital portosystemic shunts evaluated at the Veterinary Teaching Hospital during the study period.
Conclusions —Serious malformations of the abdominal veins were present in more than 1 in 20 dogs with single congenital portosystemic shunts.
Clinical Relevance —Veterinarians involved in diagnosis and surgery for portosystemic shunts should be aware of these potential malformations, and portal vein continuity should be evaluated in all dogs before attempting shunt attenuation.     

Congenital portosystemic shunts in Maltese and Australian Cattle Dogs

SUMMARY Congenital portosystemic shunts were definitively diagnosed in 62 dogs over a period of 15 years. Maltese and Australian Cattle Dogs were significantly over-represented, accounting for 14 and 13 cases, respectively. Maltese invariably had a single extrahepatic shunt derived from the left gastric or gastrosplenic vein, whereas Cattle Dogs usually had large intrahepatic shunts involving the right liver lobes. The clinical syndromes resulting from anomalous portosystemic communications were indistinguishable in the 2 breeds. Fasting blood ammonia concentration was elevated in 20 of 22 dogs tested, providing a minimally invasive and effective means of diagnosis. Complete or partial shunt attenuation was performed successfully in all 9 Maltese and in 2 of 6 Cattle Dogs in which it was attempted.     

Organic matter and water-stable aggregates in soils

The water-stability of aggregates in many soils is shown to depend on organic materials. The organic binding agents have been classified into (a) transient, mainly polysaccharides, (b), temporary, roots and fungal hyphae, and (c) persistent, resistant aromatic components associated with polyvalent metal cations, and strongly sorbed polymers. The effectiveness of various binding agents at different stages in the structural organization of aggregates is described and forms the basis of a model which illustrates the architecture of an aggregate. Roots and hyphae stabilize macro-aggregates, defined as > 250 μm diameter; consequently, macroaggregation is controlled by soil management (i.e. crop rotations), as management influences the growth of plant roots, and the oxidation of organic carbon. The water-stability of micro-aggregates depends on the persistent organic binding agents and appears to be a characteristic of the soil, independent of management.     

刨花板调供胶PLC自动控制系统的设计

概述了用可编程序控制器（ＰＬＣ）自动控制刨花板调供胶系统。首先分析了系统的生产工艺，指出了控制系统的主要设备和功能，并着重叙述了硬件、软件的设计。