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Aspergillus fumigatus is a life-threatening and increasingly frequent pathogen of the immunocompromised. Like ether filamentous fungi A. fumigatus grows in a highly polar manner, adding new cell wall to the apical region of hyphae, mAbs were raised against isolated A. fumigatus cell walls. Fifteen antibodies bound reproducibly to isolated cell walls in ELISAs and to the walls of intact cells in immunofluorescence experiments. Surprisingly, individual mAbs showed distinct patterns of localization. Six antibodies labelled exclusively conidial or basal regions, seven labelled apical regions and a single antibody labelled both basal and apical regions of hyphae. Ten antibodies did not label the walls adjacent to septa. In double labelling experiments with representative mAbs there was little or no overlap between epitopes recognized. These labelling patterns suggest that the wall is made up of basal and apical domains that differ in composition or organization and that the wall region flanking septa differs from other regions of the lateral wall. In time-course experiments of early A. fumigatus growth, mAb16C4 failed to label isotropically expanding cells and labelled emerging germ tubes and branches. The same mAb failed to label the Aspergillus nidulans swoC mutant, which is defective in polarity establishment. However, mAb16C4 did label the A. nidulans swoA mutant, which completes polarity establishment, but is defective in polarity maintenance. Thus, mAb16C4 appears to recognize a cell wall change that occurs during polarity establishment. In immunogold labelling and transmission electron microscopy (TEM) experiments, conidia, basal regions and apical regions of thin-sectioned cells labelled with mAb16C4. That only apical regions labelled in intact cells (immunofluorescence) while conidial, basal and apical regions labelled in thin-sectioned cells (TEM) suggests that the 16C4 epitope is present along the whole hypha, but is masked everywhere except the tip until polarity establishment. That is to say, some remodelling of the wall during polarity establishment exposes the 16C4 epitope. The 16C4 epitope was partially purified from A. fumigatus total protein by passage through hydrophobic interaction and anion-exchange columns. The resulting single ELISA-positive fraction showed relatively few bands by SDS-PAGE and silver staining and a strong band by Western blotting with the 16C4 mAb. Sequencing of the fraction yielded a predicted peptide with a 6-amino acid exact match to a region of the Cat1 protein previously identified as an immunodominant A. fumigatus catalase that localizes to the cell wall and is secreted to the medium. Experiments are under way to determine if mAb16C4 recognizes Cat1 or another protein that co-purifies with Cat1.

Polymorphous low-grade adenocarcinoma (PLGA) of the parotid gland is rare. We describe a new case in which the patient underwent parotidectomy only to experience an extensive recurrence 2 years later. The recurrence was treated with radical surgical excision and radiation therapy, and the patient remained disease-free at 5 years of follow-up. We also review the literature on primary parotid PLGA. [ABSTRACT FROM AUTHOR]

Discusses several topics related to neuropathology. Variants of medulloblastoma; Clinical features of oligodendroglioma and mixed oligoastrocytoma; Difference between anaplastic gangliomas and desmoplastic infantile gangliomas; Features of pathogen free inflammatory pseudotumors of the central nervous system.

Introduction: Decreased expression of syndecan-1 has been reported in dysplasia and squamous cell carcinoma (SCCA) of the oral cavity and appears to correlate with decreasing histological differentiation and poor clinical outcome. Assays of syndecan-1 expression to date have utilized manual microscopic analysis with qualitative grading of immunohistochemical staining intensity, which may introduce observer bias. We evaluated syndecan-1 expression in dysplasia and squamous cell carcinoma (SCCA) of the oral cavity, using a novel automated cellular imaging system that incorporates both staining intensity as well as the percentage of positively stained cells to yield a quantitative value for syndecan-1 expression., Materials and Methods: We performed a quantitative immunohistochemical analysis of syndecan-1 expression using an automated cellular image analysis system. We analyzed specimens from cases of mild dysplasia (N = 55), moderate dysplasia (N = 38), severe dysplasia (N = 25), carcinoma in situ (CIS) (N = 43), and SCCA of the oral cavity (N = 45), using normal mucosal epithelium (N = 21) as a positive control. The SCCA specimens were further subdivided by degree of differentiation. We retrospectively reviewed patient charts to identify tumor stage at diagnosis, recurrence, and disease-specific survival., Results: Syndecan-1 expression was significantly greater in normal controls than in specimens of mild, moderate, or severe dysplasia, CIS, or invasive SCCA (P < .05). Syndecan-1 expression did not differ significantly among specimens of mild, moderate, or severe dysplasia, CIS or SCCA. There was no significant difference in syndecan-1 expression between specimens from patients with no evidence of disease at 3 years follow-up and patients with local, regional, or distant recurrence., Conclusions: Syndecan-1 expression does not appear to be useful as a marker of differentiation or as a prognostic indicator in dysplasia and SCCA of the oral cavity. The search for a suitable and reliable marker of biological aggressiveness is ongoing.

Polymorphous low-grade adenocarcinoma (PLGA) of the parotid gland is rare. We describe a new case in which the patient underwent parotidectomy only to experience an extensive recurrence 2 years later. The recurrence was treated with radical surgical excision and radiation therapy, and the patient remained disease-free at 5 years of follow-up. We also review the literature on primary parotid PLGA.

We herein describe two cases of patients with epilepsy with occipital lobe cortical dysplasia who were studied with both MR spectroscopy and MR diffusion imaging in addition to conventional MR imaging. Greater diffusion abnormalities, as well as more marked decreases in N-acetylaspartate, were observed to occur in the patient harboring a low grade neoplasm within an area of cortical dysplasia than in the patient with cortical dysplasia alone.

Primary leiomyosarcoma of the central nervous system is rare and has been described both de novo and following temporally remote radiotherapy for a different unrelated malignancy. The authors report the case of a 42-year-old man in whom 60Co radiation treatment had been performed for an unknown primary mass in the brainstem 25 years previously. He presented with progressive neurological deterioration after undergoing many years of conservative therapy. A stereotactic biopsy sampling procedure was performed, and examination of the left cerebral pedunculopontine lesion revealed a spindle cell neoplasm. Histopathological and immunohistochemical examination of the tumor obtained from definitive resection suggested leiomyosarcomatous transformation of ganglioglioma.