Ductal Plate Malformation in the Liver of Boxer Dogs: Clinical and Histological Features.

Ductal plate malformations (DPMs) represent developmental biliary disorders with a wide phenotypic spectrum. This study characterizes DPM in 30 Boxer dogs. Median age was 1.5 (range, 0.3-10.0) years, with 12 dogs <1 year. Clinical features included increased serum levels of liver enzymes (28), gastrointestinal signs (16), poor body condition (14), abdominal effusion (9), and hepatic encephalopathy (2). Additional malformations included gallbladder atresia (8), atrophied left liver (2), absent quadrate lobe with left-displaced gallbladder (1), portal vasculature atresia (left liver, 1), intrahepatic portosystemic shunt (1), and complex intrahepatic arteriovenous malformation (1). All dogs had portal tracts dimensionally expanded by a moderate-to-severe multiple small bile duct phenotype embedded in abundant extracellular matrix; 80% displayed variable portal-to-portal bridging. Quantitative analysis confirmed significantly increased fibrillar collagen and a 3-fold increased portal tract area relative to 6 Boxer and 10 non-Boxer controls. Biliary phenotype was dominated by tightly formed CK19-positive ductules, typically 10 to 15 µm in diameter, with 3 to >30 profiles per portal tract, reduced luminal apertures, and negative Ki-67 immunoreactivity. CK19-positive biliary epithelium intersected directly with zone 1 hepatocytes as a signature feature when considered with other DPM characteristics. Phenotypic variation included a multiple small bile duct phenotype (all dogs), predominantly thin-walled sacculated ducts (4), well-formed saccular ducts (4), and sacculated segmental, interlobular, and intralobular ducts (Caroli malformation, 2 dogs, one with bridging portal fibrosis). Histologic evidence of portal venous hypoperfusion accompanied increased biliary profiles in every case. We propose that this spectrum of disorders be referred to as DPM with appropriate modifiers to characterize the unique phenotypes.

Agrometeorology and models for the parasite cycle forecast.

Insects are strongly influenced by meteorological variables in their natural environment. In agriculture, mathematical models have been developed to understand and forecast the cycle of pests based on climate data. By this manner, with the goal of reduce and rationalize plant chemical treatments, agrometeorological models have been realized to estimate the length and starting times of parasites phenological phases. In Sicily a new network of 95 GSM meteorological stations and a specific mathematical model for Aonidiella aurantii are used by Sicilian Agrometeorological Information System (SIAS) for the integrated pest management program of citrus orchards in the Island. As the plants parasites, vector borne diseases are influenced by climate in their appearance and abundance. In lights of the benefits that could derive from a model for the control of Leishmania vectors, SIAS experiences in modelling were used to develop a deductive model for Phlebotomus perniciosus which represents the major vector of human and canine leishmaniasis in Sicily.

Pathogenesis of single right coronary artery and pulmonic stenosis in English Bulldogs.

English Bulldogs are the most common breed to have pulmonic stenosis. Previous studies showed that this congenital heart abnormality in Bulldogs frequently is caused by a circumpulmonary left coronary artery originating from a single right coronary artery. Fetal anasarca also occurs often in Bulldogs and might represent congestive heart failure, but the cause is unknown. To determine if fetal anasarca is associated with a coronary anomaly and pulmonic stenosis, major coronary arteries were studied in 6 bulldog puppies with fetal anasarca. Five of the puppies had normal coronary arteries, and this led to the conclusion that fetal anasarca usually is not associated with major coronary abnormalities or pulmonic stenosis. The 6th puppy had single right coronary artery with circumpulmonary left coronary artery and moderate subvalvular pulmonic stenosis. Serial section histology suggests that the underlying cause of this syndrome is malformation of the left aortic sinus (of Valsalva) and inversion of the proximal segment of the left main coronary artery.

Diagnosis of canine fetal health by ultrasonography.

The detection of fetal pathology is important for the care of puppies in the postnatal period. The objective of this study was to identify parameters of fetal distress by determining fetal heart rate and bowel movements, and also to detect early pathology by means of fetal biometry, which involves determination of the biparietal and abdominal diameters. Ultrasonographic examinations were carried out on 30 pregnant bitches of different breeds and ages at least three times, including examination at days 40-47, days 48-57, and days 58-62 after coitus, and subsequently every 12-14 h for 3 days before parturition. Fetuses that had biparietal:abdominal diameter ratios of < 2 at the second and third series of ultrasonography, or after birth were considered to have intrauterine growth retardation. The average weight of each litter was calculated and puppies that weighed < 20% of the average weight were also considered to have experienced intrauterine growth retardation. Intrauterine growth retardation occurred in 39.6% of the bitches studied. Fetuses were considered to be normal when heart rate, determined by a Doppler flowmeter was > 220 beats min-1; suffering from slight fetal distress when heart rate was between 180 and 220 beats min-1; suffering from severe fetal distress when heart rate was < 180 beats min-1. Some level of distress was observed in 33.0% of puppies. In 86.7% of bitches, bowel movements were observed in at least one puppy, and appeared to be correlated with fetal distress. Bowel movements were observed in all of the puppies that had severe fetal distress (heart rate < 180 beats min-1), whereas bowel movements were observed in only 40.0% of puppies with slight fetal distress (heart rate 180-200 beats min-1). In conclusion, ultrasonographic evaluation allowed identification of fetuses with intrauterine growth retardation, and bowel movements were a reliable indicator of fetal distress; these conditions are presumed to indicate a greater perinatal risk.

Molecular analysis of glial cell development in the canine 'shaking pup' mutant.

The shaking pup, a canine mutant, carries a point mutation in the myelin proteolipid protein (PLP) gene that causes dysmyelination of the central nervous system (CNS) with resultant tremor, seizures, and other persistent neurological deficits. The developmental potential of glial cells in the shaking pup CNS and peripheral nervous system (PNS) was evaluated by quantitative analysis of the expression of several glial-specific genes. All of the myelin-associated genes demonstrated developmental patterns of expression similar to those observed in the controls, but at significantly reduced levels. Expression of the genes for the major CNS myelin proteins, PLP and the myelin basic protein, are most dramatically affected in the shaking pup, although reduced expression levels are observed for other oligodendrocyte-specific genes such as 2',3'-cyclic nucleotide 3'phosphodiesterase and glucose phosphate dehydrogenase. The pattern of gene expression in the shaking pup indicates that the oligodendrocytes experience an inhibition in development after the myelination program has begun. There appears to be little evidence for an astrocytic response to the dysmyelinating condition at the RNA level, but we present evidence for ectopic expression of P0 mRNA in the CNS. Expression of the P0 and PLP genes in the sciatic nerve appears to be normal, reinforcing previous reports that PNS myelination is unaffected by the mutation in the PLP gene.

Comparative prenatal development of the spinal cord in normal and dysraphic dogs: embryonic stage.

The prenatal development of the canine spinal cord was examined by light microscopy in 8 normal embryos and compared with the development of the spinal cord in 10 embryos obtained by mating severely dysraphic Weimaraner dogs. Dysraphic lesions were found in 80% of the embryos examined from dysraphic matings. The primary lesion was aberrantly positioned mantle cells ventrad to the central canal in the floor plate area. In 30% of the embryos of this group, there was a division of the terminal neural tube. The dysraphic embryos had significantly shorter gray matter and spinal cord transverse diameters. This confirmed the observation that the mantle cells in the dysraphic specimens were less differentiated, being more compact and appearing more basophilic when hematoxylin and eosin stains were used.

Pathogenesis of persistent truncus arteriosus in light of observations made in a dog embryo with the anomaly.

Among 36 embryos obtained from a strain of Keeshond dogs in which there is a large incidence of spontaneously occurring conotruncal anomalies, a specimen with persistent truncus arteriosus, type 1 was found. The embryo had a crown-rump length of 20 mm. The specimen was serially sectioned and a wax plate reconstruction was made of the heart and proximal great vessels at a magnification of X100. The truncal valve was quadricuspid and dysplastic; associated anomalies were a right subclavian artery arising anomalously from the descending aorta, a single coronary artery, an absent ductus arteriosus and a small persistent left cranial (superior) vena cava. The truncus cushions were hypoplastic, had failed to fuse and each had simply produced an arterial cusp. The observations made on this embryo support the view that in persistent truncus arteriosus there is failure of septation of the truncus arteriosus. No evidence was found in favor of the concept that persistent truncus arteriosus represents a form of tetralogy of Fallot with atresia of the subpulmonary infundibulum and partial or complete absence of the aorticopulmonary septum.