Chronic interstitial nephritis in cattle with cardiomyopathy

We tried to characterize the chronic interstitial nephritis as it occurs in bovine cardiomyopathy (CMP). For that reason conventional analysis methods were applied to urine of healthy and CMP-diseased cattle. With all the sick animals used for this study a nephritis of the mentioned type was diagnosed pathologically. By discriminant analysis of our data we were able to show, that the chronic interstitial nephritis due to CMP was best described by the variables protein (precipitation by heat), renal epithelial cells and leukocytes. In 73% of all the affected cattle one or more variables were changed pathologically to a minor to moderate degree. In the remaining 27% they were within the normal range. A possible microhematuria was secondary. Using identification analysis all the healthy animals and 69% of the diseased ones were made out correctly. As a consequence of this study we conclude, that further methods are necessary in order to recognize the different forms of nephritis more reliably.     

Pathologic and clinical features of infectious endocarditis

Infectious endocarditis is a systemic disease associated with high morbidity and mortality. Clinical recognition and effective management is challenging, but insights can be gleaned from relevant pathologic features. Risk factors include subaortic stenosis, possibly certain other congenital anomalies, and bacteremia. Auscultation can provide clues regarding valvular involvment, particularly when a diastolic left basilar murmur of aortic valve regurgitation is present. Aortic valve vegetations and insufficiency may also alter femoral arterial pulse characteristics. Echocardiography may facilitate diagnosis, particularly with aortic valve lesions, but may not be able to distinguish between small mitral valve vegetations and early chronic degenerative valve disease. Vegetative lesions develop along edges of valve closure on the ventricular aspect of the aortic valve and the atrial surface of atrioventricular valves. They may extend across valve leaflet, from valves to adjacent left atrial endocardium, interventricular or interatrial septum, or chordae tendineae. Vegetations can be friable and frequently embolize to spleen, kidney, and left ventricle — often before clinical recognition of the disease. Valvular insufficiency develops as a consequence of valvular vegetations, necrosis, perforation, or rupture of the chordae tendineae. Histopathologic appearance varies with respect to duration of disease and antimicrobial therapy. These factors influence the amount of necrotic material, blood clot, fibrin, and inflammatory cells which make up the vegetations. Bacteria are not always identified in valvular lesions, especially following antibacterial therapy, but may be detected in other organs. Common sequellae include congestive heart failure, sepsis, arrhythmias, and systemic organ infarction.     

Infectious agents identified in pigs with multifocal interstitial nephritis at slaughter

One kidney was taken from each of 100 pigs at slaughter; 50 had gross lesions of multifocal interstitial nephritis and 50 had no gross lesions. Forty-nine of the affected kidneys had lesions that were characterised by the presence of either a few randomly distributed or numerous widely disseminated pale foci, 1 to 3 mm in diameter, on the cortical surface (white-dotted kidneys). Microscopically, these focal inflammatory lesions often had a distinct lymphofollicular pattern (follicular nephritis). Lesions of chronic vasculitis were observed in 21 of the affected kidneys. Histologically, the control kidneys had only small and sparse inflammatory foci. Standard bacterial cultures of kidneys of both groups were not significant, and cultures for the isolation of leptospires were all negative. Virological examination of the kidney homogenates by PCR did not reveal any porcine reproductive and respiratory syndrome virus and only a few cases were positive for the porcine circovirus type 1. However, porcine parvovirus (PPV) and porcine circovirus type 2 (PCV-2) were detected in many kidneys of both groups but in a significantly higher proportion of the kidneys with interstitial nephritis. There was a significant association between the lesions and the presence of PPV and PCV-2 with odds ratios of 7.5 (P<0.0001) and 3.4 (P=0.0074), respectively, and the odds ratio increased to 22.7 (P<0.0001) when both viruses were identified in the same kidney. However, a subsample of kidneys taken from both groups were negative by immunohistochemistry for the presence of PPV and PCV-2 antigens.     

Pathological and aetiological studies of multifocal interstitial nephritis in wasted pigs at slaughter

Multifocal interstitial nephritis in pigs has been associated with several infectious agents. The objective of the present study was to investigate several different potential infectious agents associated with "white-spotted" kidneys in pigs suffering from wasting at slaughter (aged 6-8 months). Twenty-nine case kidneys (with a "white-spotted" gross appearance) classified into 3 macroscopic lesional grades, and 15 control kidneys (lacking gross lesions), were obtained from a pig abattoir. Laboratory analyses to detect potential associations with the aforementioned pathological condition with Leptospira spp., porcine circovirus type 2 (PCV2), porcine parvovirus (PPV), porcine reproductive and respiratory syndrome virus (PRRSV), and bacteria, were carried out. Microscopically, interstitial nephritis with a lymphofollicular inflammatory pattern (follicular nephritis) was observed in both case and control kidneys, with a higher frequency seen in the former ones. No leptospires were identified, although antibodies to the Pomona and Bratislava serovars were detected. Some pyogenic bacteria were also isolated from both case and control kidneys. PCV2 nucleic acid was only detected in 1 case kidney. PRRSV antigen was not found in any tested sample. Some pigs were tested positive for PPV by serology. Apparently, none of the studied agents were specifically associated as being the potential cause of the renal lesions in the studied wasted pigs. The fact that these chronic lesions may have been the consequence of a previous infection with one of these studied microorganisms, or more, and eventually with other non-tested infectious agents during the growing-finishing period, cannot be ruled out.     

Characterization of interstitial nephritis in pigs with naturally occurring postweaning multisystemic wasting syndrome

Kidney samples with interstitial nephritis from 26 pigs affected by postweaning multisystemic wasting syndrome (PMWS) were selected. A histologic evaluation was carried out to describe the type of inflammation and its relationship with viral load, as assessed by in situ hybridization (ISH). Of 26 cases, 10 revealed a tubulointerstitial, lymphoplasmacytic nephritis, 11 an interstitial granulomatous nephritis, and 5 both types of inflammation (mixed type). In 4 cases of granulomatous inflammation, the pattern was not classically nodular, and a population of macrophages and lymphocytes was present (interstitial lymphohistiocytic nephritis). ISH confirmed the presence of porcine circovirus type 2 (PCV2) nucleic acid in all cases. The epithelium of the renal tubules was the most constantly ISH-positive structure. In tubulointerstitial nephritis, the higher the number of positive inflammatory cells, the more severe the inflammation. The ISH reaction was more heterogeneous and unpredictable in granulomatous nephritis, with some epithelioid and giant cells positive by ISH. To quantify macrophages distributed in the three patterns of nephritis, immunohistochemical methods using anti-major histocompatibility complex II (anti-MHC-II) and anti-lysozyme antibodies were undertaken, and semiquantitative evaluation was carried out. MHC-II was mainly expressed by lymphocytes in tubulointerstitial nephritis, but did not always stain macrophages in cases of granulomatous (including lymphohistiocytic) nephritis; the anti-lysozyme antibody revealed macrophages when present in tissues. The amount of PCV2 nucleic acid was not apparently associated with the pattern of inflammation (tubulointerstitial or granulomatous). PCV2 load seems to reflect the severity of the lymphoplasmacytic inflammation but not that of granulomatous and lympho histiocytic types.     

Pathologic features of adriamycin toxicosis in young pigs: nonskeletal lesions

In ten experiments, 53 castrated male 4- to 8-week-old weanling pigs were given adriamycin (ADR) IV at mean dosages of 0.64, 1.0, 1.6, 3.2, or 6.4 mg/kg/week at various frequencies for up to 20 weeks. Mortalities in pigs given these dosages were 0% after 112 days, 100% after 134 days (survival time was 48 to 134 days), 91% after 75 days (survival time was 5 to 75 days), 100% after 28 days (survival time was 23 to 28 days), and 100% after 14 days (survival time was 10 to 14 days), respectively. Survival time was prolonged in younger pigs and in pigs given smaller but more frequent dosages of ADR. Characteristic gross and histopathologic alterations of ADR toxicosis were observed in pigs given 1.0, 1.6, 3.2, or 6.4 mg/kg/week mean dosages. The most frequent lesions were in the alimentary tract, myeloid and lymphoid tissues, skin, and perivascular tissues at injection sites. Alimentary tract lesions were mucosal epithelial atrophy, with secondary fibrinonecrotic inflammation in the oral cavity and large intestine. Marked hypoplasia was seen in bone marrow and lymphoid tissues, with frequent terminal hemorrhagic diathesis and septicemia. Several days before death, the pigs developed severe dermatitis over the ventral portion of the abdomen and inner surfaces of the limbs. Perivascular necrosis and cellulitis produced by extravasation of ADR was a frequent complication of treatment. Terminal severe acute pneumonia occurred in most pigs. Pericarditis or cardiomyopathy (or both) developed in 14 pigs, given 0.64, 1.0, or 1.6 mg/kg each week (mean cumulative dosage 520.5 mg/m2 of body surface). Characteristic histopathologic and ultrastructural alterations in affected cardiac muscle cells were vacuolar degeneration, myocytolysis, and hyaline necrosis. Nephrotoxicosis also was in pigs with chronic ADR toxicosis. Systemic antibiotic treatment did not prolong survival of ADR-treated pigs in two experiments, but did in one other experiment.     

Pathologic features of horses given avirulent equine arteritis virus intramuscularly

Twenty horses that were seronegative for equine arteritis virus antibodies were inoculated IM with live equine arteritis virus vaccine. The inoculation did not cause clinical signs of disease. A mild, transient febrile reaction developed in 6 horses, 3 of which were in poor condition before inoculation. Six horses, 2 of which were in poor condition before inoculation, experienced mild lymphopenia. Necropsy revealed mild lesions in the lymph nodes of 6 horses (3 of which were in poor condition before inoculation). Maximum concentrations of virus were detected in the lymph nodes and were consistently present from postvaccination day 3 through 8. Lesser concentrations of virus were detected in the spleen of 5 horses, liver and kidney of 4, abdominal fluid of 3, pleural fluid of 2, and lungs and urine of 1, between postvaccination days 3 and 7. Virus was not detected in the brain, nasal tract, or serum of any of the horses.     

Studies on the aetiology of non-suppurative encephalitis in pigs

Thirty-eight natural cases of aetiologically unclear non-suppurative encephalitis in pigs were studied retrospectively. Brain samples were examined for the presence of porcine circovirus type 2 (PCV-2), porcine respiratory and reproductive syndrome virus (PRRSV), porcine enteroviruses (PEVS), ovine herpesvirus type 2 (OvHV-2), Borna disease virus (BDV) and suid herpesvirus type 1 (SuHV-1) by molecular biological and immunohistochemical methods. Histological examination of the brains revealed variable degrees of lymphohistiocytic encephalitis or meningoencephalitis, characterised predominantly by perivascular mononuclear infiltrates. Two cases could be attributed to PCV-2 infection by in situ hybridisation: viral nucleic acid was found in the mesencephalon, the cerebellum and the medulla oblongata, mainly in the cytoplasm of macrophages, endothelial cells and some glial cells, which were predominantly found in the meninges and around blood vessels. Real-time PCR detected PCV-2 dna in brain samples from seven other pigs. There was no evidence of PRRSV, BDV, SuHV-1, PEVS or OvHV-2 in any of the brain samples examined.     

Pathologic features of polybrominated biphenyl toxicosis in the rat and guinea pig.

Young male rats were fed a diet containing 0, 1, 10, 100, or 500 ppm of a commercial mixture of polybrominated biphenyls (PBB) that had been accidentally incorporated into a mineral mixture and fed to Michigan livestock and poultry. After 30 days, 9 of the 12 rats in each group were killed and tissues were examined. Liver weight to body weight ratios were significantly increased at all feeding levels; at 500 ppm, liver weight had more than doubled. Kidney weight was not affected. Microscopic lesions were mostly confined to the liver and consisted of extensive swelling and vacuolation of hepatocytes in rats fed diets containing 100 and 500 ppm of PBB. Slight swelling and vacuolation were seen in rats fed the diet containing 10 ppm, and lesions were not found at 0 or 1 ppm. There was a significant increase in hepatic mitochondrial size at 1 ppm, and smooth endoplasmic reticulum was markedly increased at 100 and 500 ppm. Myelin bodies were present at 100 and 500 ppm, and vacuoles were numerous. Rats killed at 60 days had similar lesions. The activity of hepatic microsomal enzymes increased at all levels of feeding of PBB. Rat pups nursing dams fed a diet containing 10 ppm of PBB had microscopic and ultrastructural hepatic lesions. When guinea pigs were fed PBB at the same amounts as were rats, the results were strikingly different. Guinea pigs fed a diet containing 500 ppm of PBB died within 15 days; at 100 ppm, only 2 of 6 survived for 30 days. Effects on liver weight were inconsistent, but 2 of 6 fed a diet containing 10 ppm had enlarged livers.     

Pathologic features of abdominal and thoracic paragangliomas in F344/N rats

Seventeen paragangliomas were identified in a retrospective review of 200 NTP/NCI carcinogenicity studies in F344/N rats that served either as control or treated animals. Most tumors were grossly visible and located in the retroperitoneum adjacent to the vertebrae and aorta near the kidneys. Three microscopically detected paragangliomas were found at the base of the heart. Microscopically, neoplastic cells were in nests separated by reticulin fibers and capillaries. Argyrophil granules were in the cytoplasm of the retroperitoneal and mediastinal paravertebral tumors. Dense granules were found in the one tumor examined ultrastructurally. Some tumors had areas of necrosis and tumor emboli were present in the lumen of the abdominal aorta and vena cava adjacent to the tumor with metastases present in pulmonary vessels. The incidence of retroperitoneal neoplasms was 3 times more frequent in male than in female F344/N rats.