Scent‐Mark Identification and Scent‐Marking Behaviour in African Wild Dogs (Lycaon pictus)

Scent‐marking is common in mammals, but where signals are carried by urine and faeces, distinguishing between scent‐marking and mere elimination is problematic. To do so, we documented behaviours and context variables associated with urination and defecation in free‐ranging endangered African wild dogs (Lycaon pictus) and tested whether these were related to the responses of other dogs to deposits. We found that distinct postures were almost uniquely associated with deposits by dominant wild dogs, were more common during urination than defecation, and increased the likelihood that these deposits would be investigated by other wild dogs. The likelihood of investigation depended on the sex and dominance status of the depositor, the type of deposit and the substrate. Urine from dominant females was more likely to be investigated by other wild dogs than any other deposits, and deposits placed on vegetation were more likely to be investigated than those on bare ground. The likelihood that a deposit would be overmarked was affected by the deposit type and the sex and dominance status of the last depositor. Collectively, these results suggest that dominant wild dog urine is of greatest interest to other dogs. Our results show that some deposits by African wild dogs are not scent‐marks and that detailed observations of behaviours and context variables during elimination events can be used to distinguish deposits that are likely to be of communication value.     

Peritoneal effusion in a dog secondary to visceral mast cell tumor. A case report

BACKGROUND: Mast cell tumor, one of the most common skin tumors in dogs, may also be found in visceral sites (mainly spleen and liver). When a visceral mast cell tumor is present, neoplastic mast cells may be found in any effusion secondary to the tumor. Therefore, the diagnosis may be made by cytologic analysis of the effusion. CASE: An 8-year-old, spayed, female Siberian husky presented with a peritoneal effusion secondary to a visceral mast cell tumor. Seven months earlier, the dog had presented with a cutaneous nodule diagnosed as a well-differentiated mast cell tumor. The peritoneal fluid was classified as a transudate. Numerous neoplastic mast cells were found in the effusion. Although the mast cell tumor presented with characteristics of the well-differentiated tumor, its biologic behavior was that of a malignant tumor. CONCLUSION: Care should be taken to evaluate the prognosis of mast cell tumors in dogs since their biologic behavior is extremely variable.     

Experimental hepatic cryosurgery

In 28 dogs, a major portion of a lobe of the liver was frozen, either by contact with a cryoprobe or by spraying liquid nitrogen (?196 °C) over the exposed liver or by pouring liquid nitrogen into a plastic barrel placed on the lobe of the liver, which was wrapped in a Dacron velour cloth. With the probe technique, the amount of tissue that could he frozen was not as great as with direct application of liquid nitrogen to the liver. The spray technique allowed freezing of a larger area but with cracking of the liver substance with considerable mortality from bleeding. With the pour technique, even a larger area of liver could be frozen and bleeding was much less because of the protection afforded by the Dacron cloth. There were no toxic effects from the devitalized liver which was left to be resorbed. These techniques are applicable for treating localized lesions in the liver in humans, but the experiments demonstrate the difficulty of achieving great depth of freezing with any currently available technique of freezing tissue in situ. Clearly, advances in cryosurgical equipment are needed.     

Light microscopic localization of glycosyltransferase activities in cells and tissues

We describe an assay for light microscopic visualization of specific glycosyltransferases on tissue sections or on cells. The assay uses a sequence of enzyme reactions that yields two moles of NADH for each mole of the uridine-5'-diphosphate (UDP) released during transfer of a monosaccharide from a UDP sugar to an acceptor. When diaphorase and tetrazolium salts are present in the incubation mixture, the tetrazolium salts are reduced to colored diformazans, which precipitate at the sites of glycosyltransferase activity. The validity of the assay was established by applying the technique to spermatozoa and liver, in which some glycosyltransferases have previously been localized. When suspensions of mouse spermatozoa were assayed for galactosyltransferase (GalTase) activity, diformazan precipitates appeared on the plasma membranes overlying the anterior heads of the spermatozoa, in agreement with immunochemical localizations. In mouse liver slices assayed with bilirubin as acceptor for glucuronyltransferase (GluTase) activity, dense diformazan deposits appeared on the hepatocytes but not on endothelial cells, also in agreement with immunochemical data. In the absence of acceptor or UDP sugar donor, diformazan deposits were minimal and random in all tissues tested. The assay's versatility was tested by incubating tissues with different sugar donors and acceptors to localize other sites of transferase activity. In mouse frozen liver sections, GalTase activity occurred in both hepatocytes and endothelial cells; in sections of rat submaxillary glands, GalTase activity was detected in mast cells. In liver sections, GlcuTase activity with o-aminophenol as acceptor was located primarily on the endothelial cells. With the appropriate sugar donor and acceptor, this assay should detect any transferase, other than the glucosyltransferases, that utilizes UDP sugars.     

Accumulation of hydroxyapatite in the kidney of streptozotocin-induced diabetic rat fed a low-zinc diet

Calcification occurred in the kidney of streptozotocin (STZ)-induced diabetic rats fed a low-zinc diet. The deposits were stained by the von Kossa method and were detected intracellularly in the tubular cells, mainly in the cortico-medullar region. The deposits were found to be a heterogenous substance on electron microscopy. There were various sizes of deposits, and the surfactant was very much distorted. Many deposits grew up to bind small particles, and the core-like substance was observed in the center of the deposit. The component of the deposit was analyzed by an X-ray microanalyzer, and was found to be calcium and phosphorus. The ratio of calcium to phosphorus was 2.159, which coincided with the ratio of standard hydroxyapatite. From these observations, the deposit is believed to be hydroxyapatite. It is thought that the core is formed at first, many particles are then bound to the core, and deposits grow up.     

Assessment of prevalence of hydatidosis in slaughtered Sawakny sheep in Riyadh city,Saudi Arabia

Hydatidosis, or echincoccosis, is a serious medical and veterinary problem in many countries, particularly those with rural communities where there is a greater contact between dogs and domestic animals. Domestic livestock act as intermediate hosts which are the main reservoir for the disease in humans. It is therefore very important to estimate the prevalence of hydatid cysts in slaughtered animals since it can be transmitted to humans through dogs, which act as the final host for the disease. From this point of view, the present study was suggested to determine the prevalence of hydatidosis in Sawakny sheep slaughtered in Riyadh city, Saudi Arabia. During the course of the study 12,569 Sawakny sheep were inspected for hydatidosis infection. An overall prevalence of 1.06% was detected among the examined sheep, with the highest prevalence occurring in winter (1.38%) and lowest prevalence in summer (0.67%). Sheep aged 6–12 months had a higher rate of infection than older animals, and males were the predominant carriers of infection (97.7%) compared to females (2.3%). The liver was the most infected organ (79.1%), followed by the lungs (14.6%), while concurrent infections of both the liver and the lungs occurred in 6% of cases. The fertility and viability rates of hydatid cysts in the liver (70.1% and 85.1% respectively) were higher than that in any other organs. In conclusion, it is evident that fertile cysts in slaughtered sheep could have an important role in the continuation of hydatid cyst transmission to humans through dogs. Considerable effort should be devoted to controlling the transmission of cysts from abattoirs by the secure disposal of infected offal. In addition, plans are required for further epidemiological studies and control programs.     

Catalase is the bacteria-derived detoxifying substance against paramecia-killing toxin in wheat grass powder infusion

Paramecium cells are usually cultured in a wheat grass powder infusion inoculated with Klebsiella pneumoniae. However, non-bacterized wheat grass powder infusion is toxic to paramecia, and bacteria-derived substance detoxifies the toxic substance. Here, the detoxifying substance from K. pneumoniae, which was found to be proteinaceous, was purified to homogeneity. The protein had an apparent molecular mass of about 200 kDa by gel filtration and 92 kDa by SDS-polyacrylamide gel electrophoresis. Although the amino acid sequence of the amino terminal region did not show a high sequence homology with any reported proteins, amino acid sequences of internal regions of the protein were nearly identical to catalase HPII from Escherichia coli. When the wheat grass powder infusion was treated at 25 degrees C for 1 h with commercially available catalase from bovine liver, the toxicity of the infusion against paramecia was completely abolished. The initial concentration of hydrogen peroxide in the wheat grass powder infusion was about 30 microM and was completely decomposed by the catalase treatment. Therefore, the toxic substance in the wheat grass powder infusion and the detoxifying substance from K. pneumoniae are considered as hydrogen peroxide and catalase, respectively.     

Microanalytical study of thorium 232 deposits in bone marrow and liver

Summary Analytical microscopy was used to study the distribution and chemical composition of thorium deposits in bone marrow and liver after injection of thorium dioxide and thorium nitrate. Thorotrast (thorium dioxide) was identified as being localized in bone marrow macrophages of a patient who had undergone cerebral arteriography forty two years ago. Large thorotrast deposits were also present in liver cells. We show that non-colloidal thorium (thorium nitrate) injected in rats concentrates in a non soluble form in bone marrow macrophages, heptocytes and Kupffer cells. These deposits of thorium associated with phosphorus can be explained by the formation of thorium phosphate in lysosomes and we demonstrate that they remain in tissue for a long time. Microanalysis was performed with ion microscopy, and electron probe microanalysis by X ray spectrometry, which can identify and localize thorium and associated elements at cellular or intracellular level.     

Interruption of antifungal secondary prophylaxis in AIDS-related histoplasmosis

The clinical data of 21 patients, suffering AIDS-related histoplasmosis, who were able to interrupt antifungal secondary prophylaxis, after achieving a partial restoration of the cell mediated immunity by HAART administration, are presented. They were 16 males and five females, whose ages varied between 32 and 54 years (mean = 38.5 years). All of them presented disseminated progressive forms of histoplasmosis, with multiple locations (skin, mucous membranes, liver, spleen, lymph nodes and lungs). The majority of the cases suffered other concomitant diseases (specially tuberculosis and Kaposi sarcoma), 66.6 % of the patients had less than 50 CD4+ cells/microl at the start of treatment and the average viral burden was 278,385 RNA copies/ml. The initial treatment consisted in 400 mg/day of itraconazole, by oral route, in 14 cases and the remaining seven patients were treated with amphotericin B, intravenously, at a daily dose of 0.7 mg/kg of body weight. One patient who did not tolerate amphotericin B and presented a partial response to itraconazole, was treated with posaconazole orally at a daily dose of 800 mg. Fourteen patients received oral itraconazole at a daily dose of 200 mg as a secondary prophylaxis, the remaining three patients were treated with intravenous amphotericin B, 50 mg twice a week. After HAART for an average lapse of 16.7 months (10 to 32 months), five cases showed CD4+ cells counts above 150 cells/microl and the remaining 16 presented more than 200 cells/microl; 18 of them had undetectable viral burden and all cases were asymptomatic. The follow up after secondary prophylaxis discontinuation varied between six months and six years (mean= 33.6 months). Twenty out of 21 patients (95 %) were clinically stable, without any manifestation of relapses, including two patients who abandoned HAART. One patient, who discontinued HAART, contracted a fatal bacterial pneumonia. Even though the limited number of cases, the data presented in this study seem to suggest that it is possible to interrupt antifungal secondary prophylaxis of histoplasmosis, when the patient is clinically asymptomatic and the CD4+ cells counts are above 150 cells/microl.     

Glucocorticoid hepatopathy: effect on receptor-mediated endocytosis of asialoglycoproteins.

Histologic and electron microscopic examination of liver tissue from glucocorticoid-treated dogs (GT dogs) showed a markedly abnormal hepatocellular morphology which consisted of severe hepatocellular swelling, vacuolation, and peripheral displacement of subcellular organelles. The abnormal cell morphology was typical of that seen in clinical cases of canine Cushing's Syndrome. The hepatocyte isolation procedure used here works equally well for the preparation of viable hepatocytes from both normal and GT dogs even though GT dogs displayed a pronounced hepatopathy. Cell yields (10(9) cells from a 30-cm3 section of liver) are similar to those reported for rat hepatocytes using whole liver in situ perfusion and cell viability is routinely greater than 85%. The isolation procedure preserved the "abnormal" state or swollen morphology of the hepatocytes from GT dogs and thus can be used in pathophysiological studies of glucocorticoid-induced hepatopathy. The isolated hepatocytes were 3.2 times greater in cell volume than normal hepatocytes. We also observed over a 12.3-fold increase in alkaline phosphatase activity and the appearance in both the liver and the serum of GT dogs of the unique, corticosteroid alkaline phosphatase isozyme (CALP). In spite of the obvious abnormal liver morphology and elevated serum and liver alkaline phosphatase activities, the function of the hepatic cell surface carbohydrate binding protein, the Gal/GalNAc or asialoglycoprotein receptor, was not impaired. We found a trend of about a 1.5-fold increase in the initial rate of ligand uptake as well as 1.6-fold more receptors on GT dog hepatocytes compared to normal hepatocytes. The ligand binding affinity of these receptors, as well as the rate of ligand degradation, was identical in hepatocytes isolated from normal and diseased dogs. When intestinal alkaline phosphatase (IALP) is used as the ligand, approximately 25% was exocytosed intact following endocytosis. These results demonstrate that dogs with glucocorticoid hepatopathy possess a normally functioning Gal/GalNAc receptor. Furthermore, these data are consistent with the hypothesis that structurally related IALP and CALP isozymes may also be metabolically related through the Gal/GalNAc receptor endocytosis pathway. That is, a portion of the IALP normally endocytosed through the Gal/GalNAc receptor pathway in glucocorticoid-treated dogs may be recycled and converted (hyperglycosylated) to the abnormal serum CALP isozyme rather than being degraded.     

Electron microscopic studies of the parathyroid gland of senile dogs.

The parathyroid gland of healthy senile dogs aged 8.5 to 15 years was compared with that of mature control dogs by examination with the electron microscope. Preparations fixed by perfusion with glutaraldehyde showed the cytoplasmic matrix of most parenchymal cells to be uniformly dense. None of the cells were of the extremely light type and dark cells were much less frequently noted than in preparations fixed by immersion in glutaraldehyde or osmium tetroxide. Syncytial cells and so-called coloid follicles were more frequent in senile dogs than in control dogs. It was suggested that the content of the latter structures is not colloid but necrotic substance hiving origin from the parenchymal cells and that perhaps the occasional cells containing large, membrane-bound inclusions may be degenerating cells which ultimately produce this necrotic substance. Oxyphil cells and mitochondria-rich cells of another type were found in all senile dogs, but not in the controls. These cells, especially the mitochondria-rich cells, frequently contained bizarre mitochondria that were modified in shape, size and arrangement. The most striking feature of these mitochondria was the concentric arrangement of elongated mitochondria which seemed to consist of densely layered cup-shaped mitochondria. Such mitochondria were noted in all senile dogs aged ten years and over. The significance of mitochondrial ple-morphism in the parathyroid gland of senile dogs was discussed.     

Lesions in the liver and kidney of Dirofilaria immitis-infected dogs following treatment with ivermectin

Six dogs with spontaneous heartworm disease were injected with a single dose of ivermectin. After 48 h of treatment, microfilariae counts were reduced by 92%-98% of pretreatment counts. In pretreatment biopsies examined by light and electron microscopy, microfilariae were unaltered in the sinusoids of the liver and also in the glomerular capillaries and interstitial blood vessels of the kidney. However, there was irregular thickening and dense deposits in the basement membranes of glomerular capillaries, along with a modest increase in mesangial cells and matrix. In post-treatment liver biopsies examined by light microscopy, there were numerous granulomas in the sinusoids which contained degenerated microfilariae. In post-treatment kidney biopsies there was moderate thickening of glomerular basement membranes along with pronounced proliferation of mesangial cells and matrix. Glomerular capillaries were partially or completely occluded by degenerated microfilariae. In addition, there were interstitial granulomas in the kidney. It was observed with the aid of electron microscopy that highly vacuolated and degenerated microfilariae were incorporated into granulomas in the liver sinusoids of post-treatment biopsies. In post-treatment kidney biopsies glomerular capillaries were usually occluded by degenerated microfilariae. Basement membranes were thickened and contained dense deposits. Mesangial cells and matrix were extensively increased. Interstitial granulomas in the kidney contained dead microfilariae.     

Blastic OKT6-positive proliferation preceding malignant histiocytosis

A 45-year old male presented latero-cervical lymphoadenopathy. Biopsy revealed a malignant proliferation of immature "lymphoid" cells bearing T6 antigen and HLA-DR but negative for other lymphoid markers, suggesting a phenotype similar to Langerhans cells. The patient did not receive any therapy and six months later developed a histologically typical malignant histiocytosis, involving spleen and liver. Other reported cases of lymphoid malignancies (two bearing the T6 antigen on blast cells) preceding malignant histiocytosis were found and compared with ours. Most of these cases were characterized by the pediatric age of the patients and were presented as acute leukemias exhibiting, in at least some of them, reliable T-cell markers. Our case appears to represent, on the other hand, a blastic proliferation of precursors of both histiocytes and Langerhans dendritic cells which eventually progressed to malignant histiocytosis. The relevance of this observation in the debate on the origin of Langerhans cells and the relationships existing between macrophages and dendritic cells is discussed.     

COMMD1-Deficient Dogs Accumulate Copper in Hepatocytes and Provide a Good Model for Chronic Hepatitis and Fibrosis

New therapeutic concepts developed in rodent models should ideally be evaluated in large animal models prior to human clinical application. COMMD1-deficiency in dogs leads to hepatic copper accumulation and chronic hepatitis representing a Wilson's disease like phenotype. Detailed understanding of the pathogenesis and time course of this animal model is required to test its feasibility as a large animal model for chronic hepatitis. In addition to mouse models, true longitudinal studies are possible due to the size of these dogs permitting detailed analysis of the sequence of events from initial insult to final cirrhosis. Therefore, liver biopsies were taken each half year from five new born COMMD1-deficient dogs over a period of 42 months. Biopsies were used for H&E, reticulin, and rubeanic acid (copper) staining. Immunohistochemistry was performed on hepatic stellate cell (HSC) activation marker (alpha-smooth muscle actin, α-SMA), proliferation (Ki67), apoptosis (caspase-3), and bile duct and liver progenitor cell (LPC) markers keratin (K) 19 and 7. Quantitative RT-PCR and Western Blots were performed on gene products involved in the regenerative and fibrotic pathways. Maximum copper accumulation was reached at 12 months of age, which coincided with the first signs of hepatitis. HSCs were activated (α-SMA) from 18 months onwards, with increasing reticulin deposition and hepatocytic proliferation in later stages. Hepatitis and caspase-3 activity (first noticed at 18 months) increased over time. Both HGF and TGF-β1 gene expression peaked at 24 months, and thereafter decreased gradually. Both STAT3 and c-MET showed an increased time-dependent activation. Smad2/3 phosphorylation, indicative for fibrogenesis, was present at all time-points. COMMD1-deficient dogs develop chronic liver disease and cirrhosis comparable to human chronic hepatitis, although at much higher pace. Therefore they represent a genetically-defined large animal model to test clinical applicability of new therapeutics developed in rodent models.     

Stress proteins expression in rat kidney and liver chronically exposed to aluminium sulphate

Aluminium (Al) is the third most widespread metal in the environment. It is toxic for the brain, bone and haematological system but unfortunately very little data exist for other organs. Stress proteins are induced or enhanced against metal toxicity with an essential role in the recovery of organules and other cellular proteins. This immunohistochemical study was performed to analyze the distribution of three stress proteins (HSP25, HSP72, GRP75) in rat kidney and liver orally exposed to Al sulphate daily for 3 and 6 months. Al-induced alterations were further studied by histopathology (H-E, PAS, Perl's, Masson) and ultrastructural morphometry. In the kidney: HSP25 was enhanced in proximal tubules after 6 months Al-exposure when abnormal brush borders were observed; HSP72 was induced in proximal tubules only after long Al-treatment; GRP75 was raised in midcortical area sometimes within nuclei. Furthermore, lysosomal and lipofuscins densities increased in the juxtamedullary tubules after 3 months Al exposure with respect to controls. In the liver: Perl's-positive deposits and fibrosis became evident after Al treatment. HSP25 was very weak; HSP72 focal in pericentral hepatocytes at 3 months and induced also in Kupffer cells at 6 months; GRP75 diffuse in periportal hepatocytes and non parenchymal cells at 6 months. Prolonged Al exposure stimulated stress proteins strictly organ-dependently in the rat. Their distribution in kidney and liver seems related to cumulative sublethal effects induced by metal and could be a sensitive index of Al susceptibility of these organs.     

Effect of aging on neurogenesis in the canine brain

An age-dependent decline in hippocampal neurogenesis has been reported in laboratory rodents. Environmental enrichment proved to be a strong trigger of neurogenesis in young and aged laboratory rodents, which are generally kept in facilities with a paucity of environmental stimuli. These data raise the question whether an age-dependent decline in hippocampal cell proliferation and neurogenesis can also be observed in individuals exposed to diversified and varying surroundings. Therefore, we determined rates of canine hippocampal neurogenesis using post-mortem tissue from 37 nonlaboratory dogs that were exposed to a variety of environmental conditions throughout their life. Expression of the neuronal progenitor cell marker doublecortin clearly correlated with age. The analysis of doublecortin-labeled cells in dogs aged > 133 months indicated a 96% drop in the aged canine brain as compared to young adults. Expression of the proliferation marker Ki-67 in the subgranular zone decreased until dogs were aged 85-132 months. In the aging canine brain amyloid-beta peptide deposits have been described that might resemble an early pathophysiological change in the course of human Alzheimer's disease. Comparison of Ki-67 and doublecortin expression in canine brain tissue with or without diffuse plaques revealed no differences. The data indicate that occurrence of diffuse plaques in the aging brain is not sufficient to trigger enhanced proliferation or enhanced neurogenesis such as described in human Alzheimer's disease. In addition, this study gives first proof that an age-dependent decline also dominates hippocampal neurogenesis rates in individuals living in diversified environments.     

Senile Cardiac Amyloidosis in The Dog

Thirty-two cases of senile cardiac amyloidosis from a routine necropsy material of 594 dogs were studied. The age of the affected dogs ranged from 10 to 16 years. Amyloid was observed in the intramural arteries and arterioles, predominantly in the ventricular myocardium. The vessels were often obturated with amyloid, and myocardial necroses and fibroses were common consequences of the vascular lesions. In three cases amyloid deposits were also observed in the main subepicardial coronary arteries. In contrast to man, only slight interstitial amyloid degeneration was found in four of the dogs observed. Amyloid in the mitral valves, tricuspid valves and aortic cusps was observed in six, two and three cases respectively. It was concluded that the distribution of senile cardiac amyloidosis in the heart of the dog differs considerably from that in man.     

生物血管异种移植的初步研究

目的为了寻求一种新的小口径血管代用品,建立异种移植的动物实验模型,以观察异种移植物的安全性、可靠性、通畅性及组织学改变。方法共采用17只杂种雌性犬,实验组10只,植入经环氧化物处理的猪血管移植物;对照组7只,植入人造血管。手术方法为右侧股动静脉瘘。术后通过超声和血管造影方法来观察移植血管的通畅性,并在术后3月将移植物取出,进行病理学检查,观察移植前后移植物的组织学改变。结果术后第一周、二周行Doppler超声检查结果,两组动静脉瘘均通畅,2周内血管通畅率为100%。术后3个月动脉造影检查后,生物血管组(PG)通畅5只,通畅率62.5%,e-PTFE组通畅4只,通畅率66.7%。两组数据统计学处理,差异无显著性(P>0.05)。术后3月对移植物取材,进行光镜及扫描电镜病理学检查,通畅的生物血管吻合口无狭窄,吻合部位有新的内膜覆盖,周围组织无钙化,有新生的内皮细胞覆盖。结论经环氧化物处理的猪的血管移植物(PG)生物血管作为异种移植物,生物相容性好,具有一定的可行性。     

Cytological and cytochemical effects of a liver extract from an adult rat on chick embryo hepatocytes and fibroblasts cultivated in vitro]

The effects of an extract from adult liver on chick embryo hepatocytes and fibroblasts cultivated in vitro are studied with cytological and quantitative cytochemical methods. This substance inhibits the multiplication of hepatocytes adn prevents these cells from entering into the S phase of the cycle. No effect is observed on the chick embryo fibroblasts. Not any morphological alterations are observed in the two cell types.