Complete Genome Sequence of Anaeromyxobacter sp. Fw109-5, an Anaerobic, Metal-Reducing Bacterium Isolated from a Contaminated Subsurface Environment.

We report the genome sequence of Anaeromyxobacter sp. Fw109-5, isolated from nitrate- and uranium-contaminated subsurface sediment of the Oak Ridge Integrated Field-Scale Subsurface Research Challenge (IFC) site, Oak Ridge Reservation, TN. The bacterium's genome sequence will elucidate its physiological potential in subsurface sediments undergoing in situ uranium bioremediation and natural attenuation.

Detecting nitrous oxide reductase (NosZ) genes in soil metagenomes: method development and implications for the nitrogen cycle.

UNLABELLED: Microbial activities in soils, such as (incomplete) denitrification, represent major sources of nitrous oxide (N2O), a potent greenhouse gas. The key enzyme for mitigating N2O emissions is NosZ, which catalyzes N2O reduction to N2. We recently described "atypical" functional NosZ proteins encoded by both denitrifiers and nondenitrifiers, which were missed in previous environmental surveys (R. A. Sanford et al., Proc. Natl. Acad. Sci. U. S. A. 109:19709-19714, 2012, doi:10.1073/pnas.1211238109). Here, we analyzed the abundance and diversity of both nosZ types in whole-genome shotgun metagenomes from sandy and silty loam agricultural soils that typify the U.S. Midwest corn belt. First, different search algorithms and parameters for detecting nosZ metagenomic reads were evaluated based on in silico-generated (mock) metagenomes. Using the derived cutoffs, 71 distinct alleles (95% amino acid identity level) encoding typical or atypical NosZ proteins were detected in both soil types. Remarkably, more than 70% of the total nosZ reads in both soils were classified as atypical, emphasizing that prior surveys underestimated nosZ abundance. Approximately 15% of the total nosZ reads were taxonomically related to Anaeromyxobacter, which was the most abundant genus encoding atypical NosZ-type proteins in both soil types. Further analyses revealed that atypical nosZ genes outnumbered typical nosZ genes in most publicly available soil metagenomes, underscoring their potential role in mediating N2O consumption in soils. Therefore, this study provides a bioinformatics strategy to reliably detect target genes in complex short-read metagenomes and suggests that the analysis of both typical and atypical nosZ sequences is required to understand and predict N2O flux in soils. IMPORTANCE: Nitrous oxide (N2O) is a potent greenhouse gas with ozone layer destruction potential. Microbial activities control both the production and the consumption of N2O, i.e., its conversion to innocuous dinitrogen gas (N2). Until recently, consumption of N2O was attributed to bacteria encoding "typical" nitrous oxide reductase (NosZ). However, recent phylogenetic and physiological studies have shown that previously uncharacterized, functional, "atypical" NosZ proteins are encoded in genomes of diverse bacterial groups. The present study revealed that atypical nosZ genes outnumbered their typical counterparts, highlighting their potential role in N2O consumption in soils and possibly other environments. These findings advance our understanding of the diversity of microbes and functional genes involved in the nitrogen cycle and provide the means (e.g., gene sequences) to study N2O fluxes to the atmosphere and associated climate change.

Diffusion tensor imaging of tract involvement in children with pontine tumors.

BACKGROUND AND PURPOSE: Conventional MR imaging permits subcategorization of brain stem tumors by location and focality; however, assessment of white matter tract involvement by tumor is limited. Diffusion tensor imaging (DTI) is a promising method for visualizing white matter tract tumor involvement supratentorially. We investigated the ability of DTI to visualize and quantify white matter tract involvement in pontine tumors. METHODS AND MATERIALS: DTI data (echo-planar, 1.5T) were retrospectively analyzed in 7 patients with pontine tumors (6 diffuse, 1 focal), 4 patient controls, and 5 normal volunteers. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were calculated from the diffusion tensor in 6 regions of interest: bilateral corticospinal tracts, transverse pontine fibers, and medial lemnisci. Relationships between FA and ADC values and results of the neurologic examinations were evaluated. RESULTS: The corticospinal tracts and transverse pontine fibers were affected more often than the medial lemnisci. The DTI parameters (FA and ADC) were significantly altered in all tracts of patients with pontine tumors (P < .05), compared with those values in the control groups. A marginally significant (P = .057) association was seen between the severity of cranial nerve deficit and decreased FA. CONCLUSION: DTI provided superior visualization and quantification of tumor involvement in motor, sensory, and transverse pontine tracts, compared with information provided by conventional MR imaging. Thus, DTI may be a sensitive measure of tract invasion. Further prospective studies are warranted to assess the ability of DTI to delineate tumor focality and improve risk stratification in children with pontine tumors.

Morbidity of second-look surgery in pediatric central nervous system tumors.

The extent of brain tumor resection affects survival. Second-look surgery (resection of residual tumor before radiographic progression) may improve survival by reducing the tumor burden, but the morbidity of the procedure is not known. On chart review of 280 patients with two or more brain tumor operations treated between January 1985 and June 1998, we identified 47 patients with second-look surgery. Lansky and Eastern Cooperative Oncology Group (ECOG) performance scores, as well as perioperative complications were recorded. There were 21 gliomas (6 malignant), 12 medulloblastomas, 3 craniopharyngiomas, 3 ependymomas and 8 miscellaneous tumors. Median time to second surgery was 50 days. Perioperative complications occurred in 45% of patients. There was no significant change in the mean Lansky and ECOG scores 4 and 24 weeks after surgery. Gross total resection (GTR) was achieved in 62% of patients and near total resection (NTR) in 23%, and 15% of patients had subtotal resection. GTR or NTR was achieved in 66% of medulloblastomas and 100% of gliomas. We conclude that second-look surgery by experienced pediatric neurosurgeons has an acceptable morbidity and should be considered in patients with residual tumors.

Isolation and characterization of Desulfovibrio dechloracetivorans sp. nov., a marine dechlorinating bacterium growing by coupling the oxidation of acetate to the reductive dechlorination of 2-chlorophenol.

Strain SF3, a gram-negative, anaerobic, motile, short curved rod that grows by coupling the reductive dechlorination of 2-chlorophenol (2-CP) to the oxidation of acetate, was isolated from San Francisco Bay sediment. Strain SF3 grew at concentrations of NaCl ranging from 0.16 to 2.5%, but concentrations of KCl above 0. 32% inhibited growth. The isolate used acetate, fumarate, lactate, propionate, pyruvate, alanine, and ethanol as electron donors for growth coupled to reductive dechlorination. Among the halogenated aromatic compounds tested, only the ortho position of chlorophenols was reductively dechlorinated, and additional chlorines at other positions blocked ortho dechlorination. Sulfate, sulfite, thiosulfate, and nitrate were also used as electron acceptors for growth. The optimal temperature for growth was 30 degrees C, and no growth or dechlorination activity was observed at 37 degrees C. Growth by reductive dechlorination was revealed by a growth yield of about 1 g of protein per mol of 2-CP dechlorinated, and about 2.7 g of protein per mole of 2,6-dichlorophenol dechlorinated. The physiological features and 16S ribosomal DNA sequence suggest that the organism is a novel species of the genus Desulfovibrio and which we have designated Desulfovibrio dechloracetivorans. The unusual physiological feature of this strain is that it uses acetate as an electron donor and carbon source for growth with 2-CP but not with sulfate.

A detrimental effect of a combined chemotherapy-radiotherapy approach in children with diffuse intrinsic brain stem gliomas?

PURPOSE: To compare the proportion of patients that survive at least 1 year following treatment with hyper-fractionated radiotherapy (HRT) to a dose of 70.2 Gy on Pediatric Oncology Group (POG) study #8495 with that of patients treated with similar radiotherapy plus cisplatinum given by continuous infusion on weeks 1, 3, and 5 of radiotherapy on POG #9239. METHODS AND MATERIALS: The eligibility criteria for the two studies were identical and included age 3 to 21 years, previously untreated tumor involving the brain stem of which two-thirds was in the pons, history less than 6 months, and clinical findings typical for diffuse intrinsic brain stem glioma, including cranial nerve deficits, long tract signs, and ataxia. The outcome of 57 patients who were treated at the 70.2 Gy dose level of POG #8495 between May 1986 and February 1988 was compared with that of 64 patients treated with identical radiotherapy plus cisplatinum on POG #9239 between June 1992 and March 1996. RESULTS: The number of patients accrued to POG #9239 was determined to guarantee that the probability was at least 0.80 of correctly detecting that the 1-year survival rate exceeded that of patients on POG #8495 by 0.2. However, the z value for this test was -1.564, giving a p value of 0.9411. That is, there is almost sufficient evidence to conclude that survival for patients receiving HRT plus cisplatinum on POG #9239 was worse than that for patients receiving the same radiotherapy alone on POG #8495. CONCLUSION: The finding that patients who received cisplatinum given as a radiosensitizing agent concurrent with HRT fared less well than those receiving the same dose of HRT alone was unexpected and is clearly a cause for concern as many current protocols for patients with diffuse intrinsic brain stem gliomas call for use of chemotherapeutic and/or biological agents given concurrent with radiotherapy.

Pediatric low-grade and ependymal spinal cord tumors.

Our institutional experience with pediatric spinal cord tumors includes 25 patients with the diagnosis of ependymoma (EP; n = 4), myxopapillary ependymoma (MPEP; n = 4), juvenile pilocytic astrocytoma (JPA; n = 5), nonpilocytic astrocytoma (WHO grade I or II, n = 6), and other nonastrocytic spinal cord tumors (n = 6) treated during the period 1974-1999. Nineteen patients required radiation therapy (RT). The median progression-free survival following RT was 65 months (range 1-206 months). Seven patients recurred at an average of 22 months. The EP patients recurred at an average of 8.5 months, while the patients with low-grade astrocytoma recurred at an average of 42 months. Including the 6 nonsurviving patients, the median overall survival was 96 months. Two EP patients died with a progression-free survival of 9 months. One patient with MPEP died of other causes at 7 months. The treatment of pediatric spinal cord tumors should be individualized based on the histologic type. Radical surgery is indicated for nonmyxopapillary EP and low-grade astrocytic tumors. The need for adjuvant therapy most often depends on the extent of resection as well as the tumor type. Patients with disseminated EP, MPEP, JPA and nonpilocytic astrocytoma may achieve long-term progression-free survival with craniospinal irradiation.

Anaerobic naphthalene degradation by microbial pure cultures under nitrate-reducing conditions.

Pure bacterial cultures were isolated from a highly enriched denitrifying consortium previously shown to anaerobically biodegrade naphthalene. The isolates were screened for the ability to grow anaerobically in liquid culture with naphthalene as the sole source of carbon and energy in the presence of nitrate. Three naphthalene-degrading pure cultures were obtained, designated NAP-3-1, NAP-3-2, and NAP-4. Isolate NAP-3-1 tested positive for denitrification using a standard denitrification assay. Neither isolate NAP-3-2 nor isolate NAP-4 produced gas in the assay, but both consumed nitrate and NAP-4 produced significant amounts of nitrite. Isolates NAP-4 and NAP-3-1 transformed 70 to 90% of added naphthalene, and the transformation was nitrate dependent. No significant removal of naphthalene occurred under nitrate-limited conditions or in cell-free controls. Both cultures exhibited partial mineralization of naphthalene, representing 7 to 20% of the initial added (14)C-labeled naphthalene. After 57 days of incubation, the largest fraction of the radiolabel in both cultures was recovered in the cell mass (30 to 50%), with minor amounts recovered as unknown soluble metabolites. Nitrate consumption, along with the results from the (14)C radiolabel study, are consistent with the oxidation of naphthalene coupled to denitrification for NAP-3-1 and nitrate reduction to nitrite for NAP-4. Phylogenetic analyses based on 16S ribosomal DNA sequences of NAP-3-1 showed that it was closely related to Pseudomonas stutzeri and that NAP-4 was closely related to Vibrio pelagius. This is the first report we know of that demonstrates nitrate-dependent anaerobic degradation and mineralization of naphthalene by pure cultures.

CNS germinoma: disease control and long-term functional outcome for 12 children treated with craniospinal irradiation.

PURPOSE: To provide evidence that radiation therapy alone in the form of craniospinal irradiation (CSI) and a boost to the primary site of disease provides effective disease control and limited additional morbidity for patients with CNS germinoma. METHODS AND MATERIALS: Twelve patients with a median age of 12 years (range 9-16 years) with CNS germinoma were treated with CSI (median 25.6 Gy, range 23.4-32 Gy) and a boost to the primary site of disease (50.4 Gy, range 45-54 Gy) between January 1987 and June 1998. All patients were biopsied prior to radiation therapy and none received chemotherapy. No patients were lost to follow-up and the majority had long-term (> 45 month) pre- and postirradiation endocrine and psychology assessment. RESULTS: All 12 patients are alive and no failures have occurred with a median follow-up of 69 months (range 14-143 months). Preirradiation endocrine deficiencies were present in 6 of 6 suprasellar tumors and 1 of 6 pineal tumors; with follow-up there was no substantial difference between age and gender adjusted pre- and postirradiation stature and weight. With long-term follow-up, there were no significant differences between pre- and postirradiation full-scale, verbal, and performance IQ scores. CONCLUSIONS: This study confirms the ability of radiation therapy alone to achieve disease control with a high rate of success in pediatric patients and demonstrates that the treatment toxicity faced by these patients may be less than anticipated. Because these patients present with substantial preexisting morbidity at diagnosis and may be of an age where the potential for radiation-related side effects is relatively small, the superiority of treatment alternatives may be difficult to prove.

Survival and neurodevelopmental outcome of young children with medulloblastoma at St Jude Children's Research Hospital.

PURPOSE: Young children treated for medulloblastoma are at especially high risk for morbidity and mortality from their disease and therapy. This study sought to assess the relationship, if any, between patient outcome and M stage. Neuropsychologic and endocrine outcomes were also assessed. PATIENTS AND METHODS: Twenty-nine consecutively diagnosed infants and young children were treated for medulloblastoma at St Jude Children's Research Hospital between November 1984 and December 1995. All patients were treated with the intent of using postoperative chemotherapy to delay planned irradiation. RESULTS: The median age at diagnosis was 2.6 years. Six patients completed planned chemotherapy without progressive disease and underwent irradiation at completion of chemotherapy. Twenty-three children experienced disease progression during chemotherapy and underwent irradiation at the time of progression. The 5-year overall survival rate for the entire cohort was 51% +/- 10%. The 5-year progression-free survival rate was 21% +/- 8%. M stage did not impact survival. All patients lost cognitive function during and after therapy at a rate of -3.9 intelligence quotient points per year (P =.0028). Sensory functions declined significantly after therapy (P =.007). All long-term survivors required hormone replacement therapy and had growth abnormalities. CONCLUSION: The majority of infants treated for medulloblastoma experienced disease progression during initial chemotherapy. However, more than half of these patients can be cured with salvage radiation therapy, regardless of M stage. The presence of metastatic disease did not increase the risk of dying from medulloblastoma. All patients treated in this fashion have significant neuropsychologic deficits. Our experience demonstrates that medulloblastoma in infancy is a curable disease, albeit at a significant cost.

Fraction of electrons consumed in electron acceptor reduction and hydrogen thresholds as indicators of halorespiratory physiology.

Measurements of the hydrogen consumption threshold and the tracking of electrons transferred to the chlorinated electron acceptor (f(e)) reliably detected chlororespiratory physiology in both mixed cultures and pure cultures capable of using tetrachloroethene, cis-1, 2-dichloroethene, vinyl chloride, 2-chlorophenol, 3-chlorobenzoate, 3-chloro-4-hydroxybenzoate, or 1,2-dichloropropane as an electron acceptor. Hydrogen was consumed to significantly lower threshold concentrations of less than 0.4 ppmv compared with the values obtained for the same cultures without a chlorinated compound as an electron acceptor. The f(e) values ranged from 0.63 to 0.7, values which are in good agreement with theoretical calculations based on the thermodynamics of reductive dechlorination as the terminal electron-accepting process. In contrast, a mixed methanogenic culture that cometabolized 3-chlorophenol exhibited a significantly lower f(e) value, 0.012.

High-grade pediatric spinal cord tumors.

Our institutional experience with high-grade pediatric spinal cord tumors includes 11 children treated during the period of 1981-1997. All patients underwent a biopsy or an attempt at resection and received postoperative radiation therapy. Three patients had a gross-total resection of their primary tumor, 6 patients had a subtotal resection and the remaining 2 were biopsied. Histologically, these tumors were characterized as anaplastic astrocytoma (n = 6), glioblastoma multiforme (n = 3) or anaplastic oligodendroglioma (n = 2). Three patients were treated with craniospinal irradiation (38-48 Gy) in addition to a boost to the residual tumor. The median dose to the primary site for all patients was 48.6 Gy (range 38-55 Gy). The median overall survival was 13 months (range 8-149 months). Only 2 patients were alive at 138 and 149 months following radiation therapy. The median progression-free survival following radiation therapy was 10 months (range 2-80 months). There was no difference in progression-free or overall survival for those diagnosed with glioblastoma multiforme when compared to patients diagnosed with anaplastic astrocytoma or anaplastic oligodendroglioma. The pattern of failure was either diffuse or local. For the patients who failed diffusely (n = 6), the median progression-free survival was 2 months compared to 23 months for those whose failure was entirely local (p < 0.01). The median overall survival was significantly shorter for those who failed diffusely compared to those who failed locally (10 vs. 37 months, p < 0.01). High-grade spinal cord tumors in children have a poor prognosis based on this report. It is important to document the extent of disease accurately prior to the initiation of radiation therapy, since a subset of these patients progress rapidly outside of the field of irradiation.

There is no role for hyperfractionated radiotherapy in the management of children with newly diagnosed diffuse intrinsic brainstem tumors: results of a Pediatric Oncology Group phase III trial comparing conventional vs. hyperfractionated radiotherapy.

PURPOSE: In June 1992, POG began accrual to a phase III study, POG-9239, designed to compare the time to disease progression, overall survival, and toxicities observed in children with newly diagnosed brainstem tumor treated with 100 mg/m2 of infusional cisplatin and randomized to either conventional vs. hyperfractionated radiotherapy. METHODS AND MATERIALS: Patients eligible for study were those between 3 and 21 years of age with previously untreated tumors arising in the pons. Histologic confirmation of diagnosis was not mandatory, provided that the clinical and MRI scan findings were typical for a diffusely infiltrating pontine lesion. Treatment consisted of a six-week course of local field radiotherapy with either once a day treatment of 180 cGy per fraction to a total dose of 5400 cGy (arm 1) or a twice a day regimen of 117 cGy per fraction to a total dose of 7020 cGy (the second of the three hyperfractionated dose escalation levels of POG-8495) (arm 2). Because of previously reported poor results with conventional radiotherapy alone, cisplatin was included as a potential radiosensitizer in an attempt to improve progression-free and ultimate survival rates. Based on results of the phase I cisplatin dose escalation trial, POG-9139, 100 mg/m2 was chosen for this trial and was delivered by continuous infusion over a 120-hour period, beginning on the first day of radiotherapy and repeated during weeks 3 and 5. One hundred thirty eligible patients were treated on protocol, 66 on arm 1 and 64 on arm 2. RESULTS: The results we report are from time of diagnosis through October 1997. For patients treated on arm 1, the median time to disease progression (defined as time to off study) was 6 months (range 2-15 months) and the median time to death 8.5 months (range 3-24 months); survival at 1 year was 30.9% and at 2 years, 7.1%. For patients treated on arm 2, the corresponding values were 5 months (range 1-12 months) and 8 months (range 1-23 months), with 1- and 2-year survival rates at 27.0% and 6.7%, respectively. Evaluation of response by MRI at 4 or 8 wks post treatment was available in 108 patients and revealed a complete response in 1 patient of each Rx arm, a partial response (> 50% decrease in size) in 18 patients of arm 1 and 15 patients of arm 2, minimal to no response (stable) in 25 patients of arm 1 and 23 patients of arm 2, and progressive disease in 13 patients of arm 1 and 12 patients of arm 2. The pattern of failure was local in all patients. Morbidity of treatment was similar in both Rx arms, with no significant toxicity (including hearing loss) reported. Autopsy was performed in 6 patients, and confirmed the presence of extensive residual tumor in these cases. CONCLUSION: The major conclusion from this trial is that the hyperfractionated method of Rx 2 did not improve event-free survival (p = 0.96) nor did it improve survival (p = 0.65) over that of the conventional fractionation regimen of Rx 1, and that both treatments are associated with a poor disease-free and survival outcome.

Pediatric choroid plexus neoplasms.

PURPOSE: Choroid plexus tumors (CPT) are rare childhood neoplasms. The relatively small number of reported cases and the controversies surrounding the clinical and pathological classification of these tumors have made it difficult to define a standard of care for these patients. Our intention is to contribute to the body of knowledge of these tumors and further define the role of adjuvant therapy. METHODS AND MATERIALS: We performed a retrospective review of 14 children with choroid plexus neoplasms referred to St. Jude Children's Research Hospital between October 1985 and December 1987. Ten patients had choroid plexus carcinoma (CPC) based on pathologic criteria and evidence of brain invasion at surgery or leptomeningeal disease (M+); 4 patients had choroid plexus papilloma (CPP). Patients with CPP were initially treated with surgery alone whereas patients with CPC were generally treated with postoperative therapy that included chemotherapy (CT) and/or craniospinal irradiation (CSI) with a focal boost to the primary site. For most patients CT consisted of combinations of cyclophosphamide, etoposide, vincristine, and a platinum agent. The median CSI dose was 35.2 Gy (range 24-46.2 Gy). The median primary site dose was 55.2 Gy (range 49.6-64 Gy). RESULTS: Seven of the 10 CPC cases presented with leptomeningeal dissemination; two of these patients have succumbed to disease. Of the 3 patients with M0 status, all are alive with no evidence of disease (NED). The medial time to relapse from the time of surgery was 5.3 mo (range 3-25 mo). Seven CPC patients were treated with gross total resection (GTR). Three of these patients (2 M0, 1 M+) received CT without CSI and are currently NED (27, 69, and 60 mo respectively). One M+ patient progressed on CT and has stable disease after CSI (6 mo), one (M0) received CT and CSI and is NED (120 mo), one (M+) is currently on CT with objective response (3 mo) and one (M+) died of progressive disease (24.5 mo) despite CT and CSI. Three patients with CPC had subtotal resection (STR). One of these patients (M+) received CT and CSI and is NED (23 mo), one (M0) had an elective second resection GTR alone and is currently NED (153 mo), and one (M+) developed progressive disease (13.5 mo) while on CT and died despite CSI. Among the 4 CPP patients, GTR was performed in two; both were NED at 54 and 81 mo. Two patients with CPP (one with focal atypia) were treated with STR initially; both transformed to CPC at 7 and 27 mo, respectively. Both were currently NED following salvage with (1) GTR and CSI alone (98 mo) or (2) STR, CT, and CSI (62 mo). Six of the 12 survivors in this series had significant neuropsychological sequelae. CONCLUSION: The prognosis of CPP is good for patients treated with GTR. Malignant transformation occurred in 2 CPP patients with less than GTR. Patients with localized CPC who undergo GTR have had a favorable outcome with the addition of chemotherapy or irradiation. CSI may not be routinely indicated in M0 children following GTR. There is evidence that salvage with radiation therapy may be successful following progression on chemotherapy. For patients treated with STR, the use of CT and CSI appears to be necessary.

Malignant evolution of choroid plexus papilloma.

Choroid plexus tumors are rare CNS neoplasms. The distinction between choroid plexus papilloma (CPP) and choroid plexus carcinoma (CPC) is made on the basis of clinical and histological criteria. Malignant evolution of CPP may occur, and the presence of mitotic figures in CPP may predict the likelihood of recurrence or malignant evolution. Close surveillance is mandated for these patients. We report on two such cases of CPP that transformed to CPC at the time of recurrence.

Bithalamic involvement predicts poor outcome among children with thalamic glial tumors.

Clinical features and treatment of 36 consecutive pediatric patients with thalamic glial tumors confirmed by histology and characterized by neuroimaging were reviewed to identify prognostic factors. The median age at diagnosis was 10 years (range 1-18 years). Twenty-four patients had low-grade tumors (juvenile pilocytic astrocytoma n = 9, fibrillary astrocytoma n = 6, astrocytomas not otherwise specified n = 6, ganglioglioma n = 2 and oligodendroglioma n = 1) and 12 patients had high-grade tumors (glioblastoma multiforme n = 7, anaplastic astrocytoma n = 4 and unclassified malignant tumor n = 1). With a median follow-up of 4.3 years among survivors, estimates of 4-year progression-free survival (PFS) and overall survival (OS) for the entire group are 28+/-10 and 37 +/- 10%, respectively. Low-grade tumors were associated with a significantly better 4-year PFS (36 +/- 12 vs. 0% for the high-grade group; p = 0.03) and OS (52 +/- 12 vs. 0%; p < 0.001). This review identified that bithalamic involvement, characterized by neuroimaging, exerted an independent and significant negative impact on PFS and OS for patients with low-grade tumors. Estimates of 4-year PFS and OS among patients with tow-grade bithalamic versus monothalamic tumors were 58 +/- 15 vs. 0% and 85 +/- 11 vs. 0% (p < 0.00001), respectively. The presence of bithalamic involvement did not affect outcome among patients with high-grade tumors. Additionally, age at diagnosis, enhancement with neuroimaging contrast, extension beyond the thalamus and extent of surgical resection did not correlate with overall outcome. Because treatment approaches varied during the study period, the impact of radiation therapy or chemotherapy could not be assessed. This contemporary, single-institution series of pediatric thalamic glial tumors demonstrates, for the First time, the statistical significance of bithalamic involvement as a marker of poor prognosis among patients with low-grade glial lesions.

Prognostic factors in infants and very young children with intracranial ependymomas.

The Pediatric Oncology Group (1986-1990) conducted a study in which 48 children <3 years of age with intracranial ependymomas were treated with prolonged postoperative chemotherapy (CT) and delayed RT. Thirty-one children, 0-23 months of age at diagnosis (Gp A) received 2 years of CT followed by RT; while 17 children, 24-36 months of age at diagnosis (Gp B) received CT for 1 year followed by radiation. One-year survivals were 87% (Gp A) and 94% (Gp B) and 2-year survivals were 67% (Gp A) and 82% (Gp B). In subsequent years a significant divergence in survivals according to age has been noted (p = 0.04). Five-year survivals were 25.7% (Gp A) vs. 63.3% (Gp B). The curves began to diverge 1 year following diagnosis. Other than age, the only significant prognostic factor was degree of surgical resection: 5-year survivals were 66% (total resection) vs. 25% (subtotal resection). Neither the presence of metastases, degree of anaplasia nor the degree of surgical resection varied significantly according to age at diagnosis. The most likely reason for the difference in survivals between the two age groups relates to the timing of radiation following CT, i.e., 1-year delay in children 24-36 months of age compared to a 2-year delay in children 0-23 months of age. An alternative but less likely hypothesis is that ependymomas in the younger children have a more aggressive biology. In contrast, survivals in the 24- to 36-month group are much better than previous reports in the literature suggesting that prolonged postoperative CT may allow both a delay in CRT as well as provide improved survivals. Based on these results, future treatment trials should emphasize maximal surgical resection and a delay in radiation of no more than 1 year.

Antibiotic prophylaxis in dental patients with ventriculo-peritoneal shunts: a pilot study.

Fourteen hydrocephalic children with ventriculo-peritoneal shunts received routine dental prophylaxis and topical fluoride application. No antibiotics were administered to these children for any reason during the three months before treatment or during the twelve months after treatment. None of these children presented with any signs of shunt infection during the twelve-month posttreatment period. In spite of the small sample size, this prospective pilot study suggests that patients with ventriculo-peritoneal shunts are not susceptible to shunt infection following a bacteremia induced by a dental prophylaxis and topical fluoride treatment. Dental prophylaxis without antibiotic coverage in patients with V-P shunts, therefore, does appear safe. We recommend that further study with a larger population, or a collaborative study by several medical centers, be performed to establish more conclusively that prophylactic antibiotics are not necessary for patients with ventriculo-peritoneal shunts who receive dental procedures. In addition, other investigations are needed to determine the risk of shunt infection with more invasive dental procedures, such as periodontal surgery or tooth extraction.