Background and Purpose-Atherosclerotic middle cerebral arteries are frequent sites of thrombosis, leading to stroke.Previous studies have suggested a role for Chlamydia pneumoniae in the pathogenesis of atherosclerosis. However, the presence of this pathogen in atherosclerotic middle cerebral arteries has heretofore not been documented. In the present study, we analyzed atheromatous plaques from middle cerebral arteries for the presence of C pneumoniae. Methods-Atherosclerotic middle cerebral arteries from 15 cadavers who died of natural causes and corresponding nonatherosclerotic arteries from 4 otherwise healthy trauma victims were examined. Assays for C pneumoniae DNA were carried out by nested polymerase chain reaction (nPCR) specific for the C pneumoniae ompA gene. The presence of the bacterium was assessed by transmission electron microscopy. Results-Five of the 15 atherosclerotic arterial samples and none of the control tissues were positive for C pneumoniae by nPCR. Particles similar in morphology and size to C pneumoniae elementary bodies were detected by transmission electron microscopy in 4 of the 5 nPCR-positive atherosclerotic samples. Conclusions-The demonstration of C pneumoniae in atherosclerotic middle cerebral arteries is consistent with the hypothesis that this bacterium is involved in acute and chronic cerebrovascular diseases. Key Words: atherosclerosis Ⅲ C pneumoniae Ⅲ cerebrovascular disorders A therosclerosis is a multifactorial disease. The various explanations of the pathogenic process include chronic infection with certain pathogens. The microorganism most strongly implicated in the initiation/progression of atherosclerosis is the obligate intracellular bacterium Chlamydia pneumoniae, which commonly causes respiratory infections.Evidence for a possible link between C pneumoniae infection and atherosclerosis at different vascular sites has come from seroepidemiology, analysis by polymerase chain reaction (PCR), electron microscopy, in situ hybridization, immunohistochemistry, culturing, and animal models. [1][2][3][4] However, the association of chronic C pneumoniae infection and cerebrovascular diseases has not been well investigated. Case-control studies revealed that specific anti-C pneumoniae antibody levels were significantly higher in patients with cerebrovascular disease than in control patients, [5][6][7] and a follow-up study indicated that high antibody titers to C pneumoniae were associated with an increased risk of future stroke. 8 Immunoreactivity to C pneumoniae-specific antigen was recently demonstrated in a low percentage of anterior and posterior cerebral arteries but not in middle cerebral arteries. 9 The middle cerebral artery and internal carotid artery are frequent sites of thrombosis leading to stroke. One of the See Editorial Comment, page 1976 most important factors in the development of local thrombosis is the underlying atherosclerosis of the vessel wall. In the present study, we used nested PCR (nPCR) and transmission electron microscopy (TEM) to examine sa...

Objective To describe the cytopathological method used in the analysis of vitreous samples in the diagnosis of primary intraocular lymphoma (PIOL). Participants Seven patients with refractory posterior uveitis referred to a regional ocular inflammatory service were diagnosed as having PIOL between 1999 and 2006. Methods Clinical features of the uveitis and cytopathological preparation of the samples were described. All patients underwent vitrectomy and samples were placed in formal saline or prepared fresh. Following paraffin embedding generating a cell block, immunostaining, and polymerase chain reactions were performed. Results Five women (71.4%) and two men (28.6%) (mean age 67.7 years) were included. Five patients had diagnostic vitrectomy performed within 6 months of presentation, but in two patients diagnosis was delayed up to 2 years. Uveitis was bilateral in two patients. Cytologic and immunohistochemical staining prepared from the vitreous specimens showed PIOL in all patients, and PCR displayed single band of immunoglobulin heavy chain rearrangement in five out of six samples tested. Conclusions Diagnosis of PIOL is difficult due to small volume of sample with low number of malignant cells and inadequate preparation of samples. Our method of analysis with fresh samples together with immunohistochemistry and PCR analysis demonstrates a high yield of diagnosis reducing diagnostic delay.

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