Canine carotid allograft changes after photochemotherapy and external polyester sheathing.

BACKGROUND: The purpose of this study is to define and refine the changes in canine carotid allografts after photochemotherapy and polyester sheathing. Photochemotherapy with 8-methoxy psoralen (8MOP) and UVA (PUVA) was given alone or combined with intraluminal visible light (VL) 450 nm in proper dosages to speed the depopulation of endothelial (EC) and smooth muscle cells (SMC) and to modulate the immune response. METHODS: Novel apparati were made for photochemotherapy of 19 right canine carotid arterial allografts with 19 paired untreated controls in the left carotid. External UVA and internal visible light (VL 450 nm) were used with 8-methoxy psoralen (8-MOP) as a sensitizer. RESULTS: With moderate dosage of 8-MOP (1 microg/cc) and 2-4 J/cm2 of external UVA (PUVA), smooth muscle cells (SMC) disappeared faster from the media and fibroblasts (FB) appeared earlier in the adventitia of the treated right allografts, reducing but not eliminating the immune response. Intraluminal VL did not enhance the PUVA effect. At 68 days, treated and control allografts showed similar dimensions with subsided immune reactions. The media thickness was reduced from 0.38 mm to 0.18 mm and the host adventitia increased from 0.22 to 0.60 mm. Variable reactions peaked between two and three weeks and subsided after one month. All allografts remained open with canine carotid i.d.s of 2-3 mm and 80 to 100 cc/ minute arterial flows. Although the UVA dosage was moderate) similar doses sterilized log 7 of staph aureus cultures in saline. The allografts without smooth muscle showed moderate but stable cylindrical dilatation without spasm or stenosis and with an adequate adventitial buttress for a small vessel. A polyester sleeve around four treated grafts was inseparable from the allograft in less than 3 weeks and tolerated well over a 70-day period. CONCLUSIONS: Biodegradable graft sheaths with bioerodible hydrogels with growth factors (FGF) for local delivery may provide a faster and more complete matrix remodeling for a superior conduit in the future.

The use of monoclonal antibody R92F6 and polymerase chain reaction to confirm the presence of parvovirus B19 in bone marrow specimens of patients with acquired immunodeficiency syndrome.

BACKGROUND: Parvovirus B19 infection is a cause of chronic anemia and red cell aplasia in patients with acquired immunodeficiency syndrome (AIDS) and in other immunocompromised hosts. Anemia in AIDS patients has a multifactorial etiology, with parvovirus B19 infection being an infrequent but nevertheless treatable cause. Therapy with intravenous immune globulin can result in rapid improvement of parvovirus-induced anemia. This treatment is expensive, therefore accurate and rapid confirmation of parvovirus infection is important in providing appropriate and cost-effective therapy. METHODS: Bone marrow samples from 2 AIDS patients with severe anemia and reticulocytopenia were studied. Bone marrow morphology and serologic studies were evaluated for parvovirus B19 infection. An immunohistochemical method using a monoclonal antibody, R92F6, to B19 capsid proteins was utilized on decalcified, B5-fixed, paraffin-embedded bone marrow biopsies. Bone marrow aspirate cells were examined by electron microscopy for evidence of viral particles. In addition, polymerase chain reaction (PCR) studies using a nested PCR assay to the parvovirus B19 viral genome were performed in a case for which fresh cells were available. RESULTS: Bone marrow findings included marked erythroid hypoplasia with characteristic giant pronormoblasts and intranuclear inclusions. Serologic studies were negative in one case, while the second case showed positive parvovirus B19 immunoglobulin M antibody. Immunohistochemical studies for parvovirus B19 were positive in both cases. The presence of intranuclear virions was demonstrated by electron microscopy and was confirmed by PCR analysis. Both patients were treated with intravenous immune globulin, and subsequent improvement was noted. CONCLUSIONS: Both immunohistochemistry and PCR studies on bone marrow specimens from AIDS patients with anemia are rapid and sensitive methods for the confirmation of parvovirus B19 infection. They are valuable tools, particularly when serologic studies are negative. When PCR is not available, immunohistochemical methods can be useful. The rapid confirmation of parvovirus B19 infection will allow for early and cost-effective therapy.

Comparison of cardiac troponin I, creatine kinase-MB, and myoglobin for detection of acute ischemic myocardial injury in a swine model.

To study the comparative value of the levels of cardiac troponin I (cTnI), creatine kinase-MB isoenzyme (CK-MB), and myoglobin in the detection of acute ischemic myocardial injury, we serially measured plasma concentrations of these cardiac proteins in 12 pigs with myocardial ischemia subtending severe coronary artery stenoses and in 5 pigs with a sham operation performed, but without coronary artery stenosis. In the stenosis group, flow in the left anterior descending (LAD) artery was reduced by 36% and maintained for 24 hours (n = 3), 7 days (n = 6), or 4 weeks (n = 3). Flow in the coronary artery was measured by a flowmeter, and regional left ventricular dysfunction was monitored by echocardiography. Myocardial infarction was identified with triphenyltetrazolium chloride staining. All pigs with stenosis of the LAD had significant ultrastructural abnormalities consisting of loss of myofibrils and an increase in mitochondria and glycogen deposition. Cardiac proteins were released in all pigs with stenosis of the LAD artery during the development of myocardial ischemia; the levels of cTnI, CK-MB, and myoglobin increased significantly relative to the baseline. The sensitivity and specificity for cTnI were higher than for CK-MB or myoglobin. Results of this study show that cTnI is the better marker for the detection of acute ischemic myocardial injury. Increased levels of cTnI can be found in reversible and irreversible myocardial ischemic injury in this model.

Lymphangioma of the kidney: a pathologic entity distinct from solitary multilocular cyst.

A case of primary renal lymphangioma is reported. This represents the first documented example of such a lesion confirmed by immunocytochemical and ultrastructural studies. Whereas previously regarded as synonymous terms, the recognition of lymphangioma as a pathologic entity distinct from solitary multilocular cyst of the kidney appears warranted. Although rare, lymphangioma should be considered in the differential diagnosis of multicystic lesions of the kidney.

Intraductal carcinoma of major salivary gland.

The clinicopathologic features of the cases of three patients with intraductal carcinoma of major salivary gland are described. As in the breast, these lesions of salivary ducts appear to represent an in situ or preinvasive phase of the disease. On follow-up, one patient had a local recurrence, and in another patient, the tumor subsequently became invasive. This experience suggests that wide surgical excision (preferably total parotidectomy) may be curative but that resections limited to grossly visible disease will result in local recurrence and/or the development of invasive ductal adenocarcinoma.

Malignant primitive neuroectodermal tumor presenting as a scalp nodule.

We report a case of a 20-year-old woman who presented with a 3-year history of a stable cystic nodule on the scalp. Light microscopy of the excised nodule demonstrated a malignant small round cell undifferentiated neoplasm. Immunohistochemical studies suggested a neural crest origin, while ultrastructural examination revealed characteristics of schwannian differentiation. Both of these special techniques were essential in establishing the diagnosis of a malignant epithelioid schwannoma of superficial tissue (neurotropic melanoma, desmoplastic melanoma). We discuss the differential diagnoses and describe the immunohistochemical and ultrastructural characteristics of this tumor. This case illustrates the difficulty of diagnosing this rare malignant tumor, which masqueraded as a benign-appearing scalp lesion.

Glial fibrillary acidic protein expression in pleomorphic adenoma of salivary gland: an immunoelectron microscopic study.

Previous immunocytochemical studies of pleomorphic adenomas have demonstrated consistent labeling with glial fibrillary acidic protein (GFAP). Cross-reactivity with other intermediate filaments of similar structure and chemical composition has been suggested to account for this seemingly inappropriate pattern of immunoreactivity. To investigate further this phenomenon, we examined five pleomorphic adenomas by immunoelectron microscopy. Ultrastructural features were similar to those described by other investigators, with ductal epithelium being surrounded by myoepithelial cells and modified cells becoming detached to form the isolated stellate and spindle cells of the stroma. As part of this process, many neoplastic myoepithelial cells appeared to lose their specialized ultrastructural features, assuming a rather undifferentiated appearance. Single and double immunoelectron microscopic labeling showed vimentin filaments in all these neoplastic myoepithelial cells. In contrast, GFAP filaments were identified only in the most undifferentiated cells. Such restriction of GFAP filaments to an ultrastructurally definable subset of neoplastic cells provides strong evidence against nonspecific staining due to cross-reactivity. Given the previously described coexpression of vimentin and GFAP by neoplastic cartilage, it appears likely that this immunophenotype in neoplastic myoepithelial cells reflects early chondroid differentiation.

Intranasal dermal analogue tumor (membranous basal cell adenoma). Ultrastructure and immunohistochemistry.

To our knowledge, this is the first case of an intranasal monomorphic salivary gland adenoma (dermal analogue type) arising in a man exhibiting the salivary gland-skin adnexal tumor diathesis. Ultrastructurally, this tumor is composed of cells displaying squamous, secretory, luminal, and, very rarely, myoepithelial differentiation. Additionally, this is the first ultrastructural demonstration of intralobular Langerhans' cells in a dermal analogue tumor from any site. These Langerhans' cells can be demonstrated histologically by S-100 protein immunostaining. Epithelial tumor cells per se display no glial fibrillary acidic protein immunoreactivity, but rare epithelial cells stain faintly for S-100 protein. These findings seem to be distinct from pleomorphic adenoma and adenoid cystic carcinoma, the principal histologic differential diagnosis.