Systemic atherosclerosis in dogs: histopathological and immunohistochemical studies of atherosclerotic lesions

Histopathological and immunohistochemical studies were carried out on five cases of canine systemic atherosclerosis. The five animals were male, and showed hypercholesterolaemia and hypertriglyceridaemia on biochemical analysis of plasma. Histopathologically, atherosclerotic lesions were seen in the aorta and muscular arteries in many organs, including the heart, spleen, kidneys, lungs, pancreas, alimentary tract, urogenital organs, eyes, prostate and urinary bladder. The lesions were characterized by the deposition of lipids and infiltration of lipid-laden foamy cells in the tunica intima and tunica media, sometimes forming fibrofatty plaques, containing abundant sudanophilic material, cholesterol clefts and mineralized material. The lesions started in the tunica intima and extended to the tunica media and tunica adventitia. Immunohistochemical examination with canine apolipoprotein B-100 (CApoB-100) antibody identified the lipids containing low density lipoprotein. Immunoreactivity to CApoB-100 antibody was recognized in the tunica intima, lipid-laden foamy cell cytoplasm and smooth muscle cells in the tunica media, and fibrofatty plaque. These histopathological and immunohistochemical features were similar to those of human atherosclerotic lesions.

Anti-obesity effects of selective agonists to the beta 3-adrenergic receptor in dogs. I. The presence of canine beta 3-adrenergic receptor and in vivo lipomobilization by its agonists

It is known that in rodents and humans the beta 3-adrenergic receptor (beta 3-AR) is present primarily in adipocytes and plays a significant role in the adrenergic stimulation of lipolysis. We examined the expression of beta 3-AR mRNA in the dog and the lipomobilizing effects of beta 3-AR-selective agonists in vivo. Reverse transcription polymerase chain reaction of RNA extracted from dog adipose tissue produced a cDNA fragment, the nucleotide sequence of which was highly homologous to the corresponding regions of human (86.4%) and mouse (79.5%) beta 3-AR cDNA. The beta 3-AR mRNA was present at high levels in subcutaneous and visceral adipose tissues, but undetectable in other organs. When a selective beta 3-AR agonist, CL316,243, was infused intravenously into beagle dogs, the plasma level of free fatty acid increased in 30 min and persisted at higher levels for several hours. ICI D7114, another beta 3-AR agonist, also showed a similar lipomobilizing effect, but with lower potency. beta 3-AR agonist infusion also increased the plasma insulin level. These results suggested that functional beta 3-AR is present in adipose tissues of the dog and that it is effective for in vivo lipomobilization.

Anti-obesity effects of selective agonists to the beta 3-adrenergic receptor in dogs. II. Recruitment of thermogenic brown adipocytes and reduction of adiposity after chronic treatment with a beta 3-adrenergic agonist

The aim of this study was to evaluate the effectiveness of beta 3-adrenergic agonists for the treatment and prevention of obesity in the dog. When a selective beta 3-adrenergic agonist, CL316,243 (0.1 mg/kg), was given orally to adult beagles every day for 5-7 weeks, body weight and girth were decreased compared with control placebo-treated dogs. Gross anatomical examinations revealed no noticeable abnormalities in CL316,243-treated dogs, except an apparent decrease in abdominal fat. Immunohistochemical examination of perirenal adipose tissue showed a remarkable increase in brown adipocytes expressing a thermogenic protein, uncoupling protein (UCP). The increased expression of UCP and its mRNA in CL316,243-treated dogs was also confirmed by Western blot and reverse transcription polymerase chain reaction analyses. It was concluded that treatment with a beta 3-adrenergic agonist stimulates UCP expression, which may lead to an increase in energy expenditure, and thereby is useful for the treatment and prevention of obesity in the dog.

Open reduction and stabilisation of coxofemoral joint luxation in dogs and cats, using a stainless steel rope inserted via a ventral approach to the hip joint

Open reduction and stabilisation of coxofemoral joint luxation was made via a ventral approach to the hip joint in dogs and cats, using a transarticular stainless steel rope. A feature of the procedure is transarticular penetration of the rope from the pelvic cavity to the femoral neck by guidance with a guide wire which was previously inserted from the femoral neck into the pelvic cavity and by detection of the guide wire in the pelvic cavity by use of forceps connected to an alarm-ohmmeter. Forty-seven animals (37 dogs and 10 cats) with acute and simple coxofemoral luxation were treated and postoperatively maintained in cage rest without external fixation. Most of the animals regained an almost normal gait within several days.

Polyacrylamide gel electrophoretic serum protein patterns of acute inflammation induced by intramuscular injection of turpentine in young broiler chickens

Changes in the serum protein patterns accompanying inflammation in young broilers were examined by polyacrylamide gradient gel electrophoresis. Sera were obtained from blood of 4-week-old male broilers after induction of acute inflammation by an injection of 0.5 ml/kg turpentine. Electrophoretic patterns at 48 hr after injection, showed an increase in transferrin (Tf) and a segment containing albumin (Alb) with multiple peaks. The unbound iron binding capacity (UIBC) increased by 10 times, and the serum iron (SI) concentration in acute inflammation was reduced to one-half its initial value. These are considered to be typical changes in serum proteins and iron after acute inflammation.

Polyacrylamide gel electrophoretic patterns of chicken serum in acute inflammation induced by intramuscular injection of turpentine

To develop a method to detect hidden inflammation using serum protein in chickens, changes in serum proteins with acute inflammation were analyzed using a turpentine-induced inflammation model. Inflammation in the pectoral muscle of a 14-wk-old White Leghorn became apparent 3 h after the injection of turpentine and became more severe thereafter. Coincident with the development of inflammation, changes in serum proteins were analyzed by electrophoresis on polyacrylamide gradient gels. The electrophoretic patterns were divided into 21 segments. Two of these segments increased remarkably. These were located near the center of the electrophoretic pattern and were identified as transferrin due to iron staining, correlation of movement against a commercial transferrin sample in SDS-PAGE, and immunoblotting. These results suggest that transferrin may serve as a marker for inflammation in chicken.

Purification and identification of a serum protein increased by anthelmintic drugs for Dirofilaria immitis in dogs

Polyacrylamide gel electrophoretic analysis of canine serum protein has revealed that the administration of anthelmintics elicits an increase in a certain serum protein. This protein, named PT60, was partially purified by ammonium sulfate fractionation and preparative electrophoresis. The purified PT60 gave a single band with the molecular size of 53 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis under non-reducing conditions. After reduction with 2-mercaptoethanol, two bands appeared at 35 kDa and 17 kDa, indicating that PT60 consists of two subunits which are linked with each other by disulfide bonds. PT60 had the capacity to bind to hemoglobin. In an immunodiffusion test, an antiserum against PT60 cross-reacted with canine haptoglobin (Hp). N-terminal amino acid sequences of two PT60 subunits were identical to those of alpha and beta subunits of canine Hp, respectively. Thus, PT60 was identified as Hp.

Comparison of pancreatic exocrine secretion via endogenous secretin by intestinal infusion of hydrochloric acid and monocarboxylic acid in anesthetized piglets

The secretory response of the exocrine pancreas via endogenous secretin (IRS) by intraduodenal instillation of hydrochloric acid (HCl) and various monocarboxylic acid solutions was studied in anesthetized piglets. The secretion induced by HCl solutions of various concentrations containing 250 mM NaCl occurred when pH of the solutions was lower than 1.5. After instillation of the HCl solution of pH 1.0, juice flow and protein output increased 26 times and 9 times, respectively, as compared with basal levels. Such pancreatic responses paralleled an increase in plasma IRS concentration in the portal vein. The pancreatic response induced by a lactic acid solution occurred when pH of the solutions was lower than 3.8. The juice flow and protein output stimulated by a lactic acid solution of 250 mM and pH 2.0 were 16 and 8 times higher than the basal levels. The responses to the lactic acid solution of pH 2.0 increased concentration dependently, and were followed by an increase in IRS concentration in the portal vein. The pancreatic exocrine responses induced by other monocarboxylic acid solutions (250 mM) of pH 2.0 were in the following order: formic acid greater than lactic acid greater than pyruvic acid much greater than acetic acid greater than butyric acid greater than propionic acid. Lactamide, an analogous substance of lactic acid, did not evoke any pancreatic secretion. The results indicate the possibility that pancreatic exocrine response induced by HCl is dependent upon hydrogen ion, while the response induced by monocarboxylic acid is not always dependent on dissociation constant of acid.

Hepatic bile and pancreatic exocrine secretions evoked by gastrointestinal peptides in sheep

The secretory response of hepatic bile and exocrine pancreas to gastrointestinal peptides has been studied in chronically cannulated sheep. Pancreatic juice flow and protein output were evoked dose dependently by intraportal injection of secretin, CCK-8, caerulein, VIP and neurotensin. However, biliary secretion was evoked by only secretin. Biliary and pancreatic exocrine secretions were enhanced by delivered gastric juice into the duodenum as followed by the increased plasma concentration of immunoreactive secretin (IRS). Results suggest that secretin is the major peptide that regulates pancreatic exocrine secretion and hepatic bile production in the sheep.

Incorporation of nitrogen-15 from dietary [15N] diammonium citrate into amino acids of liver and muscle proteins in germfree and specific-pathogen-free neonatal pigs

Incorporation of 15N from dietary [15N]diammonium citrate ([15N]DAC) into amino acids isolated from hydrolyzed tissue proteins was investigated in the presence or absence of intestinal flora in neonatal pigs. The 15N was incorporated into all of the essential and nonessential amino acids from liver and muscles in one of two germfree pigs and two specific-pathogen-free pigs which were killed on the 5th day after the administration of [15N]DAC. But, a higher 15N concentration than natural abundance of 15N was not detected in histidine, lysine, and threonine from these tissues in another germfree pig killed the next day. Nitrogen transfer from DAC into all amino acids, including these three essential amino acids, may be possible in the specific-pathogen-free pig and even in the germfree pig.

Appearance of 15N-labeled intestinal microbial amino acids in the venous blood of the pig colon

Two experiments were done to determine whether pigs possess the ability to absorb amino acids synthesized from urea nitrogen by indigenous microbes in the large intestine. Incorporation of [15N]urea into amino acid fractions of bacterial cells from the rectum and of the deproteinized incubated medium were examined in an experiment in vitro. The isotope was incorporated into 17 amino acids and the ammonia fraction of these samples. The absorption of the microbial amino acids from the colon was investigated by determination of the 15N concentration of the free amino acids in the venous blood of the colon after infusion of the 15N-labeled microorganisms into the cecum. The increase of 15N concentration was also observed in the plasma-free amino acids (threonine, isoleucine, phenylalanine, lysine, histidine, arginine, aspartic acid, serine, alanine, cystine) of the blood from the colic branch of the ileocolic vein. The results of these experiments indicated that pigs have the ability to utilize the microbial amino acids synthesized from urea nitrogen in the large intestine.

Catheterization of the colic branch of the ileocolic vein in swine

A surgical procedure for repeated collection of blood from the colic branch of the ileocolic vein was established as an aid for nutritional studies on the colon in swine. With the animal in the dorsal position, a cannula was inserted from the ileal vein into the colic branch with a median incision at the lower part of the abdomen under a general anesthsia. Blood samples were collected intermittently every hour for 7 hours.