Comparison of diagnostic techniques for porcine proliferative enteropathy (Lawsonia intracellularis infection)

In studying the post-mortem diagnosis of porcine proliferative enteropathy (PPE) a "double-blind" study was performed on 77 apparently healthy "finisher" pigs at the time of slaughter, to compare the results of a polymerase chain reaction (PCR) technique with those of (1) an indirect immunofluorescence assay (IFA), (2) examination for gross proliferative lesions at slaughter, (3) histopathological study of sections stained with haematoxylin and eosin (HE), and (4) Warthin-Starry (WS) silver staining for intracellular bacteria. The IFA, with a sensitivity of 89% and a specificity of 97% (positive "likelihood ratio"=30) and an agreement of 82% with PCR, is suggested as an alternative to the PCR in the post-mortem diagnosis of PPE. Histopathological examination was shown to be of little use as a principal diagnostic method, although it appeared to be effective in diagnosing infection by Lawsonia intracellularis in cases with proliferative-type lesions (positive likelihood ratio=29.6). Finally, the values obtained from an examination of gross lesions (k=0.075; positive likelihood ratio of 1.3) and WS staining (k=0.42; positive likelihood ratio of 5.3) demonstrated the lack of validity of these tests for the diagnosis of L. intracellularis infection.

Acral arteriovenous tumor developed within a nevus flammeus in a patient with Sturge-Weber syndrome

The Sturge-Weber syndrome consists of a large facial nevus flammeus in the distribution of the ophthalmologic division of the trigeminal nerve accompanied by ipsilateral leptomeningeal angiomatosis. Usually, when angiomatous nodules develop in a nevus flammeus of a patient with Sturge-Weber syndrome they are pyogenic granulomas. We describe an acral arteriovenous tumor developed within the nevus flammeus of a patient with Sturge-Weber syndrome. To our knowledge, acral arteriovenous tumor has not been previously described in the cutaneous vascular malformation of patients with Sturge-Weber syndrome. The development of acral arteriovenous tumor within the vascular malformation of a nevus flammeus in this patient with Sturge-Weber syndrome probably results from a vascular proliferation secondary to underlying arteriovenous shunts.

Coinfection by Cryptosporidium parvum and porcine circovirus type 2 in weaned pigs

Routine histopathological diagnosis of one representative 3-month-old pig from a group suffering from diarrhoea revealed a massive degree of parasitation by Cryptosporidium parvum, with a concomitant infection by porcine circovirus type 2 (PCV2), that was confirmed by immunohistochemical procedures. The areas of intestine where parasites were more numerous presented abundant PCV2 infected cells in mucosa and submucosa. The concurrence of C. parvum, a rare primary intestinal pathogen in post-weaning and growing pigs, and PCV2 infections suggest an increased susceptibility as a result of an immunosuppression state.

A histopathologic, immunohistochemical, and ultrastructural study of the intestine in pigs inoculated with classical swine fever virus

The aim of this study was to report on the lesions occurring in the intestine during experimental classical swine fever (CSF) and to clarify the nature of infected cells and the distribution of viral antigen. Thirty-two pigs were inoculated with the virulent CSF virus (CSFV) isolate Alfort 187 and slaughtered from 2 to 15 postinoculation days; four animals of similar background served as a control group. Immunohistochemistry, electron microscopy, and the transferase-mediated deoxyuridine triphosphate nick-end labeling method were used to detect viral antigens and apoptosis. The results showed progressive lymphoid depletion and mucosal necrosis. The lymphoid depletion could have been caused by apoptosis of lymphocytes but could not be directly attributed to the effect of CSFV on these cells. Vascular changes, pathogenic bacteria, and viral infection of epithelial cells were ruled out as causes of necrotic lesions. However, large virally infected monocytes-macrophages with ultrastructural changes indicative of activation were observed in the intestine. This suggests that monocytes-macrophages play an important role in the pathogenesis of intestinal lesions. An understanding of the function of these cells will require additional study.

African swine fever and classical swine fever: a review of the pathogenesis

This paper describes major pathogenetic mechanisms of African and Classical Swine Fever virus infections. The interactions between both viruses and the monocyte-macrophage-system result in the release of mediator molecules, which are important for the further progression of the diseases. The causes of the thrombocytopenia and the mechanisms of the haemorrhages, which are characteristic in both infections, are described. Apoptotic cell death is regarded as the predominant cause of lymphopenia in both virus infections.

Interstitial granulomatous dermatitis with histiocytic pseudorosettes: a new histopathologic pattern in cutaneous borreliosis. Detection of Borrelia burgdorferi DNA sequences by a highly sensitive PCR-ELISA

BACKGROUND

The cutaneous manifestations of Borrelia burgdorferi infection include an early phase of erythema chronicum migrans and a late stage of acrodermatitis chronica atrophicans lesions.

OBJECTIVE

We describe 11 patients with peculiar cutaneous manifestations and distinctive histopathologic findings as the result of B burgdorferi infection.

METHODS

Eleven patients with B burgdorferi detected by polymerase chain reaction or polymerase chain reaction enzyme-linked immunosorbent assay in their cutaneous lesions were included in this study. We analyzed clinical data and histopathologic findings in all patients. The inflammatory infiltrate was also immunohistochemically investigated.

RESULTS

Most patients showed a peculiar clinical setting of morphea, and a few cases presented the characteristic appearance of erythema chronicum migrans instead of acrodermatitis chronica atrophicans, as would be expected in a late phase of B burgdorferi infection. The histopathologic findings were similar in all cases and consisted of an interstitial inflammatory infiltrate mostly composed of histiocytes dispersed among the collagen bundles of the dermis and focal areas of small pseudorosette formation, characterized by small histiocytes radially disposed around thick collagen bundles. In some cases there were also a few plasma cells intermingled with the histiocytes.

CONCLUSION

Cutaneous lesions with clinical appearance similar to that of morphea and histopathologic features closely resembling those of the interstitial type of granuloma annular may be seen in intermediate-stage cutaneous lesions of B burgdorferi infection. These clinical and histopathologic findings represent a constellation of findings that have not been previously characterized as a cutaneous manifestation of B burgdorferi infection.

Pathology of AA amyloidosis in domestic sheep and goats

We describe the main pathologic changes in small ruminants affected by AA amyloidosis, together with the partial sequence of the protein involved. Twenty-one sheep and one goat were selected for presenting macroscopic kidney lesions compatible with systemic amyloidosis. Available tissue samples were studied by histologic, immunopathologic, and ultrastructural means. Renal lesions were characterized grossly by pale cortical surfaces with scattered, miliary, whitish-yellow foci and on cut cortical surfaces by straight, whitish-yellow striations. Gangrenous pneumonia was observed in 16 out of 21 affected sheep (76.2%), although other chronic inflammations were also observed. Amyloid was detected in all grossly affected kidneys using Congo red staining, lesions being most remarkable in glomeruli, affecting 95.5% of animals studied. Congophilic deposits were also observed in intertubular interstitium (68.2%) and medulla (57.1%). All amyloid-affected animals presented proximal convoluted tubule lesions, mostly characterized by an increase in diameter and by hyaline granular degeneration that were responsible for the macroscopic appearance of the kidney. Histologically, amyloid was also seen in blood vessels, spleen, liver, lymph nodes, gastrointestinal tract, and adrenal glands. All amyloid deposits demonstrated greenish-yellow birefringence with polarized light, and the antisera prepared against goat amyloid extracts specifically reacted with birefringent congophilic deposits of both sheep and goats. Ultrastructurally, these deposits were formed by masses of straight, nonbranching fibrils located predominantly in the basement membranes of glomerular capillaries and in the mesangium. Partial sequence of the protein in sheep and goats indicated a high degree of homology with the previously reported sequence of sheep Serum Amyloid A.

Immune complex-associated thrombocytopenic purpura syndrome in sexually mature Göttingen minipigs

Eleven cases of thrombocytopenic purpura (TP) in sexually mature male or female Göttingen minipigs occurred sporadically over 3 1/2 years in a closed breeding colony protected by strict barrier conditions. Typical clinical signs of TP, including extensive subcutaneous haemorrhages, were seen in all affected animals. Haematological abnormalities included marked thrombocytopenia and anaemia. A consistent histopathological finding was the presence of membranoproliferative lesions in the renal glomeruli. Immunohistochemically, glomerular deposits were positively labelled for complement factor C1q and often also for immunoglobulins. Bone marrow findings consisting of increased numbers of immature and apoptotic megakaryocytes were compatible with a state of increased platelet consumption. Based on the combined presence of thrombocytopenia and renal immune complexes, it is suggested that the syndrome was related to a type III hypersensitivity reaction. However, further studies are needed to verify this hypothesis.

Mercury release from dental amalgams into continuously replenished liquids

OBJECTIVE

Studies have been performed using high- and low-copper amalgams to measure the amounts of mercury dissolution from dental amalgam in liquids such as artificial saliva; however, in most cases, mercury dissolution has been measured under static conditions and as such, may be self-limiting. This study measured the mercury release from low- and high-copper amalgams into flowing aqueous solutions to determine whether the total amounts of dissolution vary under these conditions when tested at neutral and acidic pH.

METHODS

High- and low-copper amalgam specimens were prepared and kept for 3 days. They were then longitudinally suspended in dissolution cells with an outlet at the bottom. Deionized water or acidic solution (pH1) was pumped through the cell. Test solutions were collected at several time periods up to 6 days or 1 month and then analyzed with a cold vapor atomic absorption spectrophotometer. After dissolution testing, the specimens were examined using SEM/XEDA for any selective degradation of the phases in the amalgam.

RESULTS

Except for the high-copper amalgam in the pH1 solution, the dissolution rates were found to decrease exponentially with time. The rate for the high-copper amalgam in pH1 solution slowly increased for 1 month. The total amounts (microgram/cm(2)) of mercury released over 6 days or 1 month from both types of amalgam in deionized water were not significantly different (p>/=0.05). The high-copper amalgam released significantly more mercury than the low-copper amalgam in the pH1 solution at both time periods. For both amalgams, the dissolution in pH1 was significantly higher than in deionized water.

SIGNIFICANCE

Mercury dissolution from amalgam under dynamic conditions is enhanced in an acidic media, and most prominently for a high-copper formulation.

Changes in macrophages in spleen and lymph nodes during acute African swine fever: expression of cytokines

To gain further insight into the pathogenesis of African swine fever (ASF), the cytokine expression by macrophages in spleen and lymph nodes were examined. Twenty-one piglets were inoculated with the highly virulent isolate Spain-70 of ASF virus and killed in groups at 1-7 post-inoculation days (pid). An increase in the immunohistochemical detection of proinflammatory monokines in spleen and renal and gastrohepatic lymph nodes is reported, along with an increase in the serum levels of TNF-alpha and IL-1 beta. The expression of these cytokines is detected simultaneously in time and space with the viral protein 73 (vp 73) of the ASF virus detection. Our results demonstrate that mononuclear phagocyte system cell activation results in the release of several cytokines that could induce apoptosis of lymphocytes and haemodynamic changes.

Glomerulonephritis associated with simultaneous canine adenovirus-1 and Dirofilaria immitis infection in a dog

This article describes a case of glomerulonephritis and immunocomplex (IgM, IgG and C3c) deposition in the mesangium and basement membranes of a 2-year-old dog with canine viral hepatitis and dirofilariasis. The deposits observed in the mesangium were in the vicinity of cells with viral replication. However, no clear relationship was found between viral replication and the deposition of immunocomplexes in the glomerular capillary basement membranes, which may be the reason why these deposits have only been tentatively related to the concomitant infestation by Dirofilaria immitis.

Chloracne: histopathologic findings in one case

BACKGROUND

Chloracne is an acneiform eruption due to poisoning by halogenated aromatic compounds having a specific molecular shape. This condition is always a symptom of systemic poisoning by chemical chloracnegens and not just a cutaneous disorder.

METHODS

We have studied a patient with severe chloracne who showed cutaneous lesions involving mostly the face and the axillae.

RESULTS

Histopathologic study of the facial lesions demonstrated that almost every vellus hair follicle was involved, showing a dilated infundibulum filled by a keratotic plug. This keratotic material was mostly composed of orthokeratotic basket-weave basophilic corneocytes, namely infundibular keratin, although there were also some dilated infundibula containing eosinophilic laminated or granular sebum at their center. Small infundibular cysts were more numerous than comedones. Mature and well-developed sebaceous glands were seen at the base of many of the dilated infundibula and no squamous metaplasia of the sebaceous glands or ducts could be demonstrated. Hyperpigmentation of the lesions resulted from hyperproduction of melanin by a normal number of melanocytes along the basal layer of the epidermis and infundibular epithelium. Abundant melanin granules also impregnated the corneocytes of the infundibular plugs.

CONCLUSIONS

Our findings support the notion that tiny infundibular cysts rather than comedones represent the basic lesions of chloracne.

Drug eruption secondary to aciclovir with recall phenomenon in a dermatome previously affected by herpes zoster

Classically, recall dermatitis refers to chemotherapy-induced reactivation of skin damage caused by radiotherapy months, or even years, earlier. The concept of recall dermatitis has now been extended to include radiation recall dermatitis induced by other drugs, ultraviolet radiation, extravasation of drugs, and allergic contact dermatitis. We now describe recall dermatitis along the residual cutaneous lesions of a previous thoracic herpes zoster in a patient who developed a drug eruption after oral administration of aciclovir. The most striking feature consisted of confluent linear erythema along the dermatomes previously involved by the herpes zoster episode. Histopathologic study demonstrated small foci of spongiosis, vacuolar changes involving the basal layer of the epidermis and single necrotic keratinocytes scattered within the epidermis. The papillary dermis appeared oedematous and with dilated blood capillaries surrounded by a sparse inflammatory infiltrate composed mainly of lymphocytes. Serial sections failed to demonstrate cytologic changes of herpes varicella zoster infection. We interpreted this case as an example of recall dermatitis because the widespread cutaneous eruption secondary to aciclovir was more intense in skin previously compromised by herpes varicella zoster infection. To the best of our knowledge, recall dermatitis has not been described before at the site of previous involvement by herpes zoster.

Cutaneous metastases from Ewing's sarcoma: report of two cases

Ewing's sarcoma is a malignant osseous neoplasm that affects mostly children and young adult males. Clinically, the neoplasm presents with oedema, swelling, and pain of the involved area. Histopathologically, Ewing's sarcoma consists of solid sheets of small round cells, with vesicular nuclei and scant cytoplasm, arranged in irregular masses separated by strands of fibrous tissue, with areas of necrosis en masse intermingled with intratumoural haemorrhage. Ewing's sarcoma is an extremely aggressive neoplasm and metastases to sites such as lung, pleura, other bones, central nervous system, liver, and regional lymph nodes frequently develop in early stages of the disease. Surprisingly, despite the highly aggressive biological behaviour of this neoplasm, cutaneous metastases from Ewing's sarcoma are very uncommon. We report two patients with Ewing's sarcoma of the bone who developed cutaneous metastases. As in other internal malignancies, the onset of cutaneous metastases in patients with Ewing's sarcoma indicates a poor prognosis.

Immunolocalization of the smooth muscle-specific protein calponin in complex and mixed tumors of the mammary gland of the dog: assessment of the morphogenetic role of the myoepithelium

The immunohistochemical expression of the smooth muscle-specific protein calponin was studied to assess the contribution of myoepithelial cells to the histogenesis of spindle cells of complex and mixed tumors of the mammary gland of the dog and the origin of cartilage and bone in mixed tumors. Formalin-fixed tissues from 55 benign and malignant tumors (49 also containing surrounding normal mammary gland) were evaluated. Periacinar and periductal myoepithelial cells of all the 49 normal mammary glands were diffusely stained by the anti-human calponin monoclonal antibody. Calponin was found in 53 (98%) of the tumors studied, reacting with the myoepithelium-like cells of 86% of benign tumors and their remnants in 85% of malignant tumors. Five different types of calponin-immunoreactive myoepithelial cells were identified: hypertrophic myoepithelial cells. fusiform cells, stellate myoepithelial cells, rounded (myoepithelial) cells, and chondroblasts. Differences in staining intensity and staining pattern among these five types of cells suggested a transition of myoepithelial cells to chondroblasts. Stromal myofibroblasts also showed calponin immunoreactivity, but they did not react with a cytokeratin 14 monoclonal antibody, which recognizes myoepithelial cells in mammary gland. Calponin appears to be a very sensitive marker of normal and neoplastic myoepithelium in the canine mammary gland, and its identification in different cell types of complex and mixed tumors of the mammary gland of the dog suggests a major histogenetic role for myoepithelial cells.

Hepatitis associated with herpes viral infection in the tortoise (Testudo horsfieldii)

Herpesvirus infection in tortoises is largely characterized by the development of respiratory clinical signs. Usually lesions develop in the respiratory, oral pharyngeal, intestinal tract and are accompanied by cutaneous and ocular lesions. In chelonids affected by herpesvirus, systemic-type lesions in organs such as the liver and spleen are commonly observed. In this paper we describe a case of multifocal necrotic hepatitis associated with herpesviruses in an adult female land tortoise of the species Testudo horsfieldii. This article is the first description of a viral hepatitis in Testudo spp. with lesions compatible with herpesvirus infection, with no clinical signs or lesions in the respiratory system, oral cavity or other organs.

African swine fever: Expression of interleukin-1 alpha and tumour necrosis factor-alpha by pulmonary intravascular macrophages

To determine, in the acute form of African swine fever (ASF), the relationship between the appearance of pulmonary oedema and viral replication and expression of cytokines by pulmonary intravascular macrophages (PIMs), 14 pigs were inoculated intramuscularly with ASF virus (strain España'70) and killed in pairs on days 1-7 post-inoculation. Samples of lung were examined immunohistochemically and ultrastructurally. The immunohistochemical study was carried out with antibodies against interleukin-1 alpha (IL-1alpha), tumour necrosis factor-alpha (TNF-alpha), viral antigen of ASF (Vp73) and a myeloid marker (SWC3). Viral replication was observed mainly in PIMs, which at the same time showed intense activation, accompanied by the expression of IL-1alpha and TNF-alpha. The occurrence of interstitial oedema, neutrophil sequestration and fibrin microthrombi in septal capillaries coincided with high degrees of cytokine expression by infected PIMs. Alveolar macrophages did not show a significant change in cytokine expression as a result of ASF infection, and viral replication was detected in only a low percentage of these cells.

Early platelet aggregation as a cause of thrombocytopenia in classical swine fever

Twenty pigs were inoculated with a virulent classical swine fever virus isolate to determine the mechanism responsible for thrombocytopenia using histopathologic, ultrastructural, and immunohistochemical (detection of viral antigens gp55 and FVIII-rag) techniques. In animals euthanatized at 2, 4, and 6 days postinoculation (dpi), clusters of granular material staining positive for FVIII-rag were observed in splenic cords, the marginal zone, hepatic sinusoids, and the perisinusoidal space. Moreover, numerous macrophages in these areas were swollen and displayed an intensely positive granular and cytoplasmic reaction. Cell alterations indicative of platelet activation and secretory and phagocytic activation of resident macrophages were also observed in these sites at 2 and 4 dpi. These results suggest that the thrombocytopenia observed in pigs is caused in the first instance by massive activation and subsequent phagocytosis of platelets secondary to the release of platelet-activating factors by activated macrophages.

Olmsted syndrome: report of a case with study of the cellular proliferation in keratoderma

Olmsted syndrome is a rare disorder that consists of sharply marginated keratoderma of the palms and soles, constriction of digits and toes that may result in spontaneous amputation of the distal phalanges, hyperkeratotic plaques around the body orifices, onychodystrophy, and other less common cutaneous and extracutaneous anomalies. Although some patients had other affected family members, most cases of Olmsted syndrome seem to be of sporadic occurrence. We describe a patient with the characteristic features of Olmsted syndrome. The symptoms consisted of diffuse transgrediens palmoplantar keratoderma and keratotic plaques around the mouth and nose. Our patient also had the associated anomalies of hyperhidrosis of the palms and soles and congenital deaf-mutism. Histopathologic study of the keratoderma demonstrated epidermal hyperplasia with acanthosis, papillomatosis, and orthokeratotic hyperkeratosis. Immunohistochemical study showed more basal and suprabasal keratinocytes of the epidermis with immunoreactivity for Ki-67 marker when compared with the keratinocytes of the epidermis of the adjacent non-involved skin. These results support the notion that Olmsted syndrome is a hyperproliferative disorder of the epidermis.

HIV-1 protease cleaves eukaryotic initiation factor 4G and inhibits cap-dependent translation

Several animal viruses inhibit host protein synthesis, but only some members of the picornavirus group are known to do so by cleaving translation initiation factor eIF4G. Here we report that infection of human CD4(+) cells with HIV-1 also leads to proteolysis of eIF4G and profound inhibition of cellular translation. Purified HIV-1 protease directly cleaves eIF4GI at positions 678, 681, and 1086, separating the three domains of this initiation factor. Proteolysis of eIF4GI by HIV-1 protease, as with poliovirus 2A protease, inhibits protein synthesis directed by capped mRNAs but allows internal ribosome entry site-driven translation. These findings indicate that HIV-1, a member of retrovirus group, shares with picornaviruses the capacity to proteolyze eIF4G.