Pilomyxoid astrocytoma: expanding the imaging spectrum.

BACKGROUND AND PURPOSE: Pilomyxoid astrocytoma (PMA) is a recently described variant of pilocytic astrocytoma (PA) with unique clinical and histopathologic characteristics. Because the histopathology of PMA is distinct from that of PA, we hypothesized that PMAs would display distinctive imaging characteristics. We retrospectively reviewed the imaging findings in a large number of patients with PMA to identify these characteristics. MATERIALS AND METHODS: CT and MR images, pathology reports, and clinical information from 21 patients with pathology-confirmed PMA from 7 institutions were retrospectively reviewed. CT and MR imaging findings, including location, size, signal intensity, hemorrhage, and enhancement pattern, were tabulated. RESULTS: Patients ranged in age from 9 months to 46 years at initial diagnosis. Sex ratio was 12:9 (M/F). Twelve of 21 (57%) tumors were located in the hypothalamic/chiasmatic/third ventricular region. Nine (43%) occurred in other locations, including the parietal lobe (2/21), temporal lobe (2/21), cerebellum (2/21), basal ganglia (2/21), and fourth ventricle (1/21). Ten (48%) tumors showed heterogeneous rim enhancement, 9 (43%) showed uniform enhancement, and 2 (9%) showed no enhancement. Five (24%) masses demonstrated intratumoral hemorrhage. CONCLUSION: This series expands the clinical and imaging spectrum of PMA and identifies characteristics that should suggest consideration of this uncommon diagnosis. One third of patients were older children and adults. Almost half of all tumors were located outside the typical hypothalamic/chiasmatic region. Intratumoral hemorrhage occurred in one quarter of patients. PMA remains a histologic diagnosis without definitive imaging findings that distinguish it from PA.

The Crohn's disease-associated bacterial protein I2 is a novel enteric t cell superantigen.

An aberrant T cell response to enteric bacteria is important in inflammatory bowel disease. However, the identity of relevant microbial antigens is unknown. Here, we report the presence of I2, a Crohn's disease-associated microbial gene, in the murine intestine. The I2 protein induced a proliferative and IL-10 response by CD4(+) T cells from unimmunized mice. The I2 response was dependent on MHC class II-mediated recognition but did not require antigen processing. Selective activation was observed for the TCR-Vbeta5 subpopulation. These findings indicate that the I2 protein is a new class of T cell superantigen and suggest that colonization by the I2 microorganism in susceptible hosts may provide a superantigenic stimulus pertinent to Crohn's disease pathogenesis.

Identification of a novel bacterial sequence associated with Crohn's disease.

BACKGROUND & AIMS: Enteric microorganisms are implicated in the pathogenesis of Crohn's disease (CD), but no clear bacterial or viral species has been identified. In this study, representational difference analysis (RDA) was used to isolate DNA segments preferentially abundant in lamina propria mononuclear cells of lesional mucosa vs. adjacent uninvolved mucosa. METHODS: Two RDA-derived microbial sequences were isolated (I1 and I2) and identified as novel homologues of the ptxR and tetR bacterial transcription-factor families. RESULTS: Quantitative competitive polymerase chain reaction of paraffin-embedded intestinal specimens from 212 patients showed that I2 DNA was present in many CD colonic lesions (43%), but was infrequent in other colonic specimens (9% of ulcerative colitis lesions and 5% of non-inflammatory bowel disease diseases; P<0.0001). I2 was prevalent in ileal specimens, regardless of disease status (43%-54%). Enzyme-linked immunosorbent assay analysis of 150 individuals with an I2 glutathione-S-transferase fusion protein showed frequent immunoglobulin A seroreactivity in CD (54% of patients), but infrequent seroreactivity in patients with ulcerative colitis, other inflammatory enteric diseases, or normals (10%, 19%, and 4%, respectively; P<0.001 to 0.00001). CONCLUSIONS: These findings relate CD to a novel lesion-localized and immunologically associated bacterial sequence, suggesting that the microorganism expressing the I2 gene product may be related to CD pathogenesis.

Familial expression of anti-Saccharomyces cerevisiae mannan antibodies in affected and unaffected relatives of patients with Crohn's disease.

BACKGROUND: Crohn's disease is a familial disorder, and antiglycan antibodies to the cell wall mannan of Saccharomyces cerevisiae (ASCA) are highly correlated with Crohn's disease. AIMS: To determine whether there is a familial pattern for expression of serum levels of anti-mannan Ig, and whether this trait is expressed in clinically unaffected Crohn's disease family members. METHODS: 349 patients with Crohn's disease, 87 Crohn's disease affected relatives, 333 inflammatory bowel disease (IBD) free relatives, 58 spouses, and 190 healthy control patients were studied. Serum IgG and IgA binding activity to S cerevisiae cell wall mannan was quantitated by ELISA. RESULTS: A high percentage of patients with Crohn's disease (51.9%) and affected family members (56.3%) were seropositive for anti-mannan Ig, compared with the normal control population (3.7%). Seropositive and seronegative phenotypes of Crohn's disease probands were correlated among all affected relatives, and this association was stronger in affected first degree relatives. Statistical intraclass correlations of quantitative anti-mannan Ig levels revealed significantly less variation within, rather than between families. A significant familial aggregation was observed for affected relatives; this was even stronger for unaffected relatives. While a significant familial aggregation was observed among unaffected siblings pairs, there was no significant correlation among marital pairs. CONCLUSION: Results show that anti-mannan Ig in family members affected and unaffected with Crohn's disease is a familial trait for both affected and unaffected relatives. The lack of concordance in marital pairs indicates that familiality is due in part to a genetic factor or childhood environmental exposure.

Moyamoya disease in the United States.

The epidemiology and radiological features of Moyamoya disease (MMD) in the US were investigated. This study encompassed 98 cases; 26 were newly collected from eight US institutions and 72 were previously reported in the US literature. The patients ranged in age from 6 months to 67 years with age peaks in the first, third and fourth decades. MMD was seen in various ethnic groups and females were more commonly involved (71%) than males. A specific etiology could not be determined in most cases but arteriosclerosis and use of oral contraceptives were occasional associations. On angiography and/or magnetic resonance angiography (MRA), carotid arterial stenosis or occlusion was seen bilaterally in 95 cases (97%) and unilaterally in three. On MR or MRA, internal carotid steno-occlusive lesions were well demonstrated in all cases but Moyamoya collateral vessels (MMVs) were visualized in only 65% of the patients. MMVs in the basal ganglia and thalami were best demonstrated on T1 weighted images. Parenchymal lesions were seen in all patients and were often bilateral. With advances in MR techniques and increasing awareness of diagnostic guidelines, MMD will be diagnosed more frequently than before in the US.

Tumoral calcium pyrophosphate dihydrate deposition disease mimicking a cervical spine neoplasm: case report.

A case of tumoral calcium pyrophosphate dihydrate crystal deposition disease involving the upper cervical spine is reported. It presented clinically, radiographically, and by preliminary intraoperative pathological evaluation as a possible malignant soft tissue tumor. An aggressive resection of the lesion was performed. This case differs from previous reports of calcium pyrophosphate dihydrate crystal deposition disease of the cervical spine by the size, location, and radiographic appearance of the lesion. We suggest that radical surgical procedures should not be performed without consideration of this diagnosis in lesions with similar presentations. A brief review of spinal and tumoral calcium pyrophosphate dihydrate crystal deposition is presented.

Transforming the Escherichia coli Trp repressor into a site-specific nuclease.

The Escherichia coli Trp repressor has been converted into an operator-specific nuclease by alkylating cysteine-49, inserted by site-directed mutagenesis, with 5-(iodoacetamido)-1,10-phenanthroline. In the presence of copper ion and thiol, high yields (> 50%) of double-stranded breaks of DNA are observed after a 20-min reaction. The high cleavage efficiency of this derivatized protein (Trp repressor E49C-OP) can be attributed to the proximity of cysteine-49 to the minor groove, the site of the C-1H of the deoxyribose and the target of the oxidative nuclease activity of (1,10-phenanthroline)copper. Since sequence position 49 is close to the protein's C2 dyad axis and adjacent to the minor groove, Trp repressor E49C-OP reacts with the operator DNA near the binding site of this symmetry locus of the protein. The patterns of scission of the trpR, aroH, and trpEDCBA operators (a) confirm the orientation of the repressor to the operator predicted from the X-ray study of a cocrystal (Otwinowski et al., 1988) and (b) support the model for tandem binding of the repressor to the trpR, aroH, and trpEDCBA operators based on DNase I footprinting and methylation interference (Kumamoto et al., 1987). There are one, two, and three binding sites for the repressor on the trpR, aroH, and trpEDCBA operators, respectively. In addition to providing a novel approach to studying the interactions of DNA binding proteins, 1,10-phenanthroline-derivatized proteins such as Trp repressor E49C-OP may be useful as rare cutters in the analysis of high molecular weight DNAs, especially if their binding specificities can be altered.

Asymmetric radiographic findings in the pediatric chest: approach to early diagnosis.

Several conditions in children produce a mass effect within one hemithorax, which may be life threatening. The different radiographic appearances of these conditions provide a basis on which they can be classified. The three major categories include a large cystic hemithorax, a large lucent hemithorax, and a large opaque hemithorax. Some disorders may be seen within more than one major group. Within the large cystic hemithorax group, congenital cystic adenomatoid malformation and congenital diaphragmatic hernia may be life-threatening conditions that require emergency surgery. The large lucent hemithorax is usually caused by pneumothorax, partial bronchial occlusion, or compensatory hyperinflation of the unobstructed lung. The majority of cases within the large opaque hemithorax group involve pleural fluid collections. Because many conditions that cause a mass effect require intervention or surgery, accurate interpretation of the plain chest radiograph is essential for an early diagnosis. Classification of radiographic features into these three groups often allows accurate diagnosis without additional studies.

Ovarian masses revisited: radiologic and pathologic correlation.

Diagnosis of ovarian masses can be difficult because many pathologic conditions can affect the ovary and have similar clinical and radiologic manifestations. Knowledge of pathologic, age-specific characteristics can help refine the differential diagnosis. Ovarian masses are nonneoplastic (ovarian functional cysts, polycystic ovary disease, and ovarian torsion) or neoplastic (surface epithelial, sex cord-stromal, germ cell, and metastatic tumors). Functional cysts, if complicated by hemorrhage, can have a confusing ultrasonographic (US) appearance. Polycystic disease and torsion are easily diagnosed with US. Benign and malignant forms of serous and mucinous surface epithelial tumors can usually be differentiated with US. Imaging features of surface epithelial tumors of low malignant potential are nonspecific, resembling those of benign serous and mucinous tumors. Mature (benign) teratomas are usually cystic, with components of fat, soft tissue, and calcium, and are sonographically distinct from immature (malignant) teratomas, which are mostly solid. Sex cord-stromal tumors occur more often in menopausal or postmenopausal women and are typically solid. Metastatic disease is less common than other ovarian tumors; however, its radiologic appearance may resemble those of other masses.