Isolation and identification of Legionella spp. from non-hospital facilities: a preliminary one-year surveillance study in the urban area of Pesaro-Urbino (Central Italy).

BACKGROUND: Legionella is considered one of the most important causes of potentially preventable morbid-ity and mortality. These microorganisms are ubiquitous, but incomplete information is available on the geographic distribution of Legionella species in our region. STUDY DESIGN: For the mentioned reasons, in this work the distribution of Legionella spp. in non-hospital facilities of the urban area of Pesaro-Urbino (Central Italy), including public fountains, residential build-ings, public and private offices and retirement homes, was investigated. METHODS: A total of 298 water samples were collected from the different facilities and subjected to standard Legionella isolation and identification protocols. RESULTS: As reported, 17.8% of the collected water samples resulted positive for Legionella spp. (28.6% from retirement homes, 21.3% from residential buildings, 15.3% from private and public offices). The highest per-centage of positive samples (14.4%) was found in hot water from retirements homes (58.8%) and residential buildings (31.8%); the most frequent isolated serogroups were L. pneumophila 2-14 (71.7%). CONCLUSIONS: This work is the first describing the distribution of Legionella spp. in non-hospital facilities in the province of Pesaro-Urbino, and highlights a condition of potential risk for susceptible categories. From our data, we can point that a regular and constant control to prevent microbiological risk from legionellosis, particularly in facilities housing the elderly, is recommended.

Prevalence and characteristics of positional plagiocephaly in healthy full-term infants at 8-12 weeks of life.

Positional plagiocephaly (PP) denotes flattening of the skull that occurs frequently in healthy infants. Aim of this study was to estimate the prevalence of positional plagiocephaly and to identify the risk factors in a cohort of healthy infants in order to help prevention of PP. In a prospective design, all healthy full-term infants, ranging from 8 to 12 weeks of age, who presented at the public immunization clinic in Ferrara, were eligible for the study. After obtaining informed consent, we interviewed the parents and examined the infants using the Argenta's assessment tool. Of 283 infants examined, 107 (37.8%) were found to have PP at 8-12 weeks of age. In 64.5%, PP was on the right side, 50.5% were male and 15% presented also with brachycephaly. Risk factors significantly associated were lower head circumference, advanced maternal age, Italian compared to African, and supine sleep position, in particular for infants born at 37 weeks, preference for one side of the head. In logistic regression, risk factors significantly associated were lower birth weight, advanced maternal age, and supine sleep position. CONCLUSIONS: Positional plagiocephaly is a common issue faced by pediatricians; our results reinforce the need of improving prevention both of sudden infant death and positional plagiocephaly, through uniform messages provided prenatally and postnatally by different health professionals. "What is Known:" •The incidence of positional plagiocephaly varies due to population studied and measuring methods. •Different factors are considered in the literature as being associated to positional plagiocephaly (infant factors, obstetric factors, infant care practices, sociodemographic factors). "What is New:" •This is one of the few European studies quantifying positional plagiocephaly prevalence in a population of unselected healthy infants. •In this study, positional plagiocephaly is confirmed as a common issue, related to some factor (as supine sleep position and positional head prevalence) that should be addressed in pre and postnatal counseling. •The prone sleepers rate in our population highlight the need to improve parental awareness regarding SIDS prevention, in particular in borderline gestational age.

Ultraviolet germicidal irradiation in tap water contaminated by Aspergillus spp.

We investigated the effect of ultraviolet germicidal irradiation (UVI) from a low-pressure mercury lamp on several pathogenic Aspergillus spp. including A. flavipes, A. flavus, A. fumigatus, A. glaucus, A. nidulans, A. niger, A. terreus, A. ustus and A. versicolor suspended in tap water under laboratory-scale conditions. It was shown that within 10 s of exposure, time species such as A. glaucus, A. niudulans and A. ustus were completely inactivated, while 40 s were needed for the elimination of all the species tested. A. flavus and A. niger were found to be less susceptible than other species. Based on these results we conclude that UV disinfection could effectively inactivate Aspergillus spp. in tap water. Such disinfection could be used to reduce potential exposure of high-risk patients to fungal aerosols, particularly in hospital settings, where point-of-use (POU) UV light devices could be installed to provide safe water at a very low cost.

Nuclear lipid droplets: a novel nuclear domain.

We investigated nuclear neutral-lipid (NL) composition and organization, as NL may represent an alternative source for providing fatty acids and cholesterol (C) to membranes, signaling paths, and transcription factors in the nucleus. We show here that nuclear NL were organized into nonpolar domains in the form of nuclear-lipid droplets (nLD). By fluorescent confocal microscopy, representative nLD were observed in situ within the nuclei of rat hepatocytes in vivo and HepG2 cells, maintained under standard conditions in culture, and within nuclei isolated from rat liver. nLD were resistant to Triton X-100 and became stained with Sudan Red, OsO4, and BODIPY493/503. nLD and control cytosolic-lipid droplets (cLD) were isolated from rat-liver nuclei and from homogenates, respectively, by sucrose-gradient sedimentation. Lipids were extracted, separated by thin-layer chromatography, and quantified. nLD were composed of 37% lipids and 63% proteins. The nLD lipid composition was as follows: 19% triacylglycerols (TAG), 39% cholesteryl esters, 27% C, and 15% polar lipids; whereas the cLD composition contained different proportions of these same lipid classes, in particular 91% TAG. The TAG fatty acids from both lipid droplets were enriched in oleic, linoleic, and palmitic acids. The TAG from the nLD corresponded to a small pool, whereas the TAG from the cLD constituted the main cellular pool (at about 100% yield from the total homogenate). In conclusion, nLD are a domain within the nucleus where NL are stored and organized and may be involved in nuclear lipid homeostasis.

A phase 2, randomized, blinded, dose-finding, controlled clinical trial to evaluate the safety, tolerability, and immunogenicity of a 24-valent pneumococcal conjugate vaccine (VAX-24) in healthy adults 65 years and older.

Despite current polysaccharide and conjugate vaccine use, pneumococcal diseases remain prevalent in older adults. VAX-24 is a 24-valent pneumococcal conjugate vaccine (PCV) containing eCRM, a proprietary carrier protein with non-native amino acids (para-azidomethyl-L-phenylalanine) that undergo site-specific conjugation to pneumococcal polysaccharides that have been activated with a small-molecule linker (dibenzocyclooctyne). Site-specific conjugation utilizing click chemistry enables consistent exposure of T-cell epitopes, reduction in carrier protein to pneumococcal polysaccharide ratio, and enhances manufacturing process consistency to improve PCVs by increasing serotype coverage while minimizing carrier suppression. Healthy adults aged 65 or older were randomized in a 1:1:1:1 ratio to receive a single injection of VAX-24 at 1 of 3 dose levels (1.1, 2.2, or a mixed dose of 2.2 or 4.4 mcg) or Prevnar 20® (PCV20) in a phase 2, blinded study. Primary outcome measures were solicited local and systemic events within 7 days post-vaccination, unsolicited adverse events (AEs) within 1 month, and serious AEs, medically attended AEs, or new onset of chronic disease within 6 months of vaccination. Serotype-specific opsonophagocytic activity (OPA) and immunoglobulin G (IgG) were measured pre-vaccination and at 1 month post-vaccination. Of 207 participants enrolled, 200 completed the trial. Safety profiles were comparable across the three VAX-24 doses and PCV20. Robust OPA and IgG immune responses were seen for all 24 serotypes. On average, immune responses to VAX-24 2.2 mcg dose were similar or higher compared to PCV20. In adults ≥ 65 years, VAX-24 had a safety profile similar to PCV20 through six months post-vaccination and induced robust OPA and IgG responses to all 24 serotypes, supporting prior data showing that site-specific conjugation allows for increased serotype coverage with similar or higher immune response vs other PCVs. The outcome of this phase 2 study further supports use of VAX-24 2.2 mcg dose in phase 3 trials. Clinicaltrials.gov: NCT05297578.

First measurement of the partial widths of 209Bi decay to the ground and to the first excited states.

209Bi alpha decay to the ground and to the first excited state have been recently observed for the first time with a large BGO scintillating bolometer. The half-life of 209Bi is determined to be τ(1/2)=(2.01±0.08)×10(19) yr while the branching ratio for the ground-state to ground-state transition is (98.8±0.3)%.

Asynchrony in Peritumoral Resting-State Blood Oxygen Level-Dependent fMRI Predicts Meningioma Grade and Invasion.

BACKGROUND AND PURPOSE: Meningioma grade is determined by histologic analysis, with detectable brain invasion resulting in a diagnosis of grade II or III tumor. However, tissue undersampling is a common problem, and invasive parts of the tumor can be missed, resulting in the incorrect assignment of a lower grade. Radiographic biomarkers may be able to improve the diagnosis of grade and identify targets for biopsy. Prior work in patients with gliomas has shown that the resting-state blood oxygen level-dependent fMRI signal within these tumors is not synchronous with normal brain. We hypothesized that blood oxygen level-dependent asynchrony, a functional marker of vascular dysregulation, could predict meningioma grade. MATERIALS AND METHODS: We identified 25 patients with grade I and 11 patients with grade II or III meningiomas. Blood oxygen level-dependent time-series were extracted from the tumor and the radiographically normal control hemisphere and were included as predictors in a multiple linear regression to generate a blood oxygen level-dependent asynchrony map, in which negative values signify synchronous and positive values signify asynchronous activity relative to healthy brain. Masks of blood oxygen level-dependent asynchrony were created for each patient, and the fraction of the mask that extended beyond the contrast-enhancing tumor was computed. RESULTS: The spatial extent of blood oxygen level-dependent asynchrony was greater in high (grades II and III) than in low (I) grade tumors (P < 0.001) and could discriminate grade with high accuracy (area under the curve = 0.88). CONCLUSIONS: Blood oxygen level-dependent asynchrony radiographically discriminates meningioma grade and may provide targets for biopsy collection to aid in histologic diagnosis.

A Multiparametric Model for Mapping Cellularity in Glioblastoma Using Radiographically Localized Biopsies.

BACKGROUND AND PURPOSE: The complex MR imaging appearance of glioblastoma is a function of underlying histopathologic heterogeneity. A better understanding of these correlations, particularly the influence of infiltrating glioma cells and vasogenic edema on T2 and diffusivity signal in nonenhancing areas, has important implications in the management of these patients. With localized biopsies, the objective of this study was to generate a model capable of predicting cellularity at each voxel within an entire tumor volume as a function of signal intensity, thus providing a means of quantifying tumor infiltration into surrounding brain tissue. MATERIALS AND METHODS: Ninety-one localized biopsies were obtained from 36 patients with glioblastoma. Signal intensities corresponding to these samples were derived from T1-postcontrast subtraction, T2-FLAIR, and ADC sequences by using an automated coregistration algorithm. Cell density was calculated for each specimen by using an automated cell-counting algorithm. Signal intensity was plotted against cell density for each MR image. RESULTS: T2-FLAIR (r = -0.61) and ADC (r = -0.63) sequences were inversely correlated with cell density. T1-postcontrast (r = 0.69) subtraction was directly correlated with cell density. Combining these relationships yielded a multiparametric model with improved correlation (r = 0.74), suggesting that each sequence offers different and complementary information. CONCLUSIONS: Using localized biopsies, we have generated a model that illustrates a quantitative and significant relationship between MR signal and cell density. Projecting this relationship over the entire tumor volume allows mapping of the intratumoral heterogeneity in both the contrast-enhancing tumor core and nonenhancing margins of glioblastoma and may be used to guide extended surgical resection, localized biopsies, and radiation field mapping.

[Disinfection efficiency of peracetic acid, alone and in combination with hypochlorite, against Mycobacterium avium in drinking water]. / Efficacia disinfettante dell'acido peracetico (PAA), da solo o in combinazione con il cloro, nei confronti di Mycobacterium avium in acqua destinata al consumo umano.

Peracetic acid (PAA) is a disinfectant with a wide spectrum of antimicrobial activity, but little is known about the feasibility of using it in the field of drinking water treatment. The aim of this study has been assess disinfectant efficacy of PAA, alone or in combination with hypochlorite, against M. avium in drinking water M. avium is a common opportunistic pathogen in immunocompromised subjects that is able to survive and grow in drinking water distribution systems. In this study PAA did not show appreciable activity against the greater number of tested strains (16/21) up to 5 ppm of PAA, a weak activity was seen on 4 strains, while a significant reduction in viable cells (about 50%) was seen only on 1 strain after 48 h of treatment with 5 ppm of PAA. We also evidenced that M. avium was unaffected by chlorine concentration usually present in drinking water distribution system. Finally, the combination of PAA and sodium hypochlorite did not promote enhanced antimicrobial efficacy respect to the single disinfectants. In conclusion, our result would indicate that PAA is an unlikely candidate for the disinfection of drinking water from M. avium and further strategies are required to eliminate M. avium from drinking water system.

Peak exercise oxygen consumption in chronic heart failure: toward efficient use in the individual patient.

OBJECTIVES: This study sought to 1) assess the short-, medium-and long-term prognostic power of peak oxygen consumption (VO2) in patients with heart failure; 2) verify the consistency of a nonmeasurable anaerobic threshold (AT) as a criterion of nonapplicability of peak VO2; 3) develop simple rules for the efficient use of peak VO2 in individualized prognostic stratification and clinical decision making. BACKGROUND: Peak VO2, when AT is identified, is among the indicators for heart transplant eligibility. However, in clinical practice the application of defined peak VO2 cutoff values to all patients could be inappropriate and misleading. METHODS: Six hundred fifty-three patients consecutively considered for eligibility for heart transplantation were followed up. Outcomes (cardiac death and urgent transplantation) were determined when all survivors had a minimum of 6 months of follow-up. RESULTS: Contraindication to the exercise test identified very high risk patients. The relatively small sample of women did not allow inferences to be drawn. In men, peak VO2 stratified into three levels (< or = 10, 10 to 18 and >18 ml/kg per min) identified groups at high, medium and low risk, respectively. The prognostic power of peak VO2 < or = 10 ml/kg per min was maintained even when the AT was not detected. In patients in New York Heart Association functional class III or IV, peak VO2 did not have prognostic power. In patients in functional class I or II, peak VO2 stratification was prognostically valuable, but less so at 6 than at 12 or 24 months. Age did not influence peak VO2 prognostic stratification. CONCLUSIONS: A contraindication to exercise testing should be considered a priority for listing patients for heart transplantation. Only in less symptomatic male patients does a peak VO2 < or = 10 ml/kg per min identify short-, medium- and long-term high risk groups. A peak VO2 >18 ml/kg per min implies good prognosis with medical therapy.

HOLMES: The electron capture decay of [Formula: see text]Ho to measure the electron neutrino mass with sub-eV sensitivity.

The European Research Council has recently funded HOLMES, a new experiment to directly measure the neutrino mass. HOLMES will perform a calorimetric measurement of the energy released in the decay of [Formula: see text]Ho. The calorimetric measurement eliminates systematic uncertainties arising from the use of external beta sources, as in experiments with beta spectrometers. This measurement was proposed in 1982 by A. De Rujula and M. Lusignoli, but only recently the detector technological progress allowed to design a sensitive experiment. HOLMES will deploy a large array of low temperature microcalorimeters with implanted [Formula: see text]Ho nuclei. The resulting mass sensitivity will be as low as 0.4 eV. HOLMES will be an important step forward in the direct neutrino mass measurement with a calorimetric approach as an alternative to spectrometry. It will also establish the potential of this approach to extend the sensitivity down to 0.1 eV. We outline here the project with its technical challenges and perspectives.

Developmental deficits in adult patients with arteriovenous malformations.

BACKGROUND: Cerebral arteriovenous malformations (AVMs) are congenital masses of arteries and veins that appear to undergo an unclear "maturation" for many years. Using structured interviews, we compared developmental history of adult patients with AVM with a comparison group of patients with cerebral tumor or aneurysm. OBJECTIVE: To determine whether a remote history of developmental abnormality in adult patients with AVM might be an early marker of cerebral status. DESIGN: Adult patients with AVM and a comparison group of patients with cerebral aneurysm or low-grade tumor participated in a survey. SETTING: Urban medical school-based tertiary care center. PATIENTS: Forty-four randomly selected patients with AVM from the Columbia-Presbyterian AVM Database. There were 32 comparison patients:15 randomly chosen patients from the institution's Cerebral Aneurysm Database and all 17 patients who underwent a biopsy from 1990 to 1995 with a diagnosis of low-grade tumor and who could be contacted. MAIN OUTCOME MEASURES: A brief, structured interview adapted from the Centers for Disease Control and Prevention for its 1994 study of the prevalence of learning disabilities in American children. We defined the positive occurrence of a condition as an affirmative answer to the question, " Did have (condition) during his/her school-age years?" Each patient was also asked if there had been any problems in the following skill areas: reading, writing, listening, speaking, attention, impulsivity, organization, mathematics, or drawing. The AVM size was calculated on the angiographic film by measuring its longest diameter in any dimension. RESULTS: Patients with AVM were significantly more likely to report a positive occurrence to any survey question (P<.05). Two thirds of all patients with AVM (66%) reported at least 1 skill difficulty during their school years, significantly more than the comparison group (P<.001). Neither the maximum AVM diameter nor the occurrence of hemorrhage as an adult differed between patients with AVM with and without early skill difficulty. CONCLUSIONS: Patients with AVM are more likely to report a developmental learning disorder than patients with tumor or aneurysm despite the absence of other neurologic symptoms of diseases not diagnosed for another 20 years. These data support the notion that disorders of behavioral and intellectual function are sensitive markers of early cerebral status.

[GdPCP2A(H(2)O)(2)](-): a paramagnetic contrast agent designed for improved applications in magnetic resonance imaging.

A novel ligand based on a pyridine-containing macrocycle bearing two acetic and one methylenephosphonic arms (PCP2A) has been synthesized. An efficient synthesis of PCP2A is based on the macrocyclization reaction between 2,6-bis(chloromethyl)pyridine and a 1,4, 7-triazaheptane derivative bearing a methylenephosphonate group on N-4. The Gd(III) complex of PCP2A displays characteristic properties which make it a very promising contrast agent for improved applications in magnetic resonance imaging. In fact it shows (i) a very high stability constant (log K(GdPCP2A) = 23.4) which should guarantee against the in vivo release of toxic free Gd(III) ions and free ligand molecules and (ii) a relaxivity that is about 2 times higher than the values reported for contrast agents currently used in the clinical practice. Its high relaxivity is the result of the presence of two water molecules in the inner coordination sphere and a significant contribution from water molecule(s) hydrogen bonded to the phosphonate group. Moreover, the inner sphere water molecules are involved in an exchange with the bulk water which is relatively fast. This property is important for the attainment of an even higher relaxivity once the molecular reorientation rate of the [GdPCP2A(H(2)O)(2)](-) moiety is lengthened by means of conjugation to a macromolecular substrate.

Progressive multifocal leukoencephalopathy in patients with human immunodeficiency virus.

Lesions of progressive multifocal leukoencephalopathy (PML) in patients infected with the human immunodeficiency virus (HIV) often have mononuclear cell infiltrates so intense that they obscure the nature of the lesion. This response may be especially prominent in stereotactic biopsies of contrast-enhancing areas. Of 10 consecutive PML lesions biopsied stereotactically, three were markedly, two were moderately, and five were mildly inflamed. There were few to no enlarged oligodendrocytic nuclei with inclusions in the markedly and moderately inflamed lesions. We investigated all biopsies with immunoperoxidase, DNA in situ hybridization, polymerase chain reaction, and Southern immunoblot methodologies for toxoplasmosis and the following viruses: JC, cytomegalovirus, herpes simplex viruses I and II, and human T-cell lymphotropic viruses I, II, and III. We confirmed the presence of JC virus in each lesion; polymerase chain reaction revealed HIV genome only in one. Inflammatory PML lesions in HIV+ patients do not reflect co-infection with toxoplasmosis or viruses commonly seen in these patients. The mononuclear cells are primarily T lymphocytes. Patients with severely inflamed PML lesions, whether HIV+ or not, often show stabilization of symptoms with or without antiviral treatment and have longer lengths of survival than patients with less inflamed lesions.

High-dose thiotepa and etoposide-based regimens with autologous hematopoietic support for high-risk or recurrent CNS tumors in children and adults.

The prognosis in patients with primary brain tumors treated with surgery, radiotherapy and conventional chemotherapy remains poor. To improve outcome, combination high-dose chemotherapy (HDC) has been explored in children, but rarely in adults. This study was performed to determine the tolerability of three-drug combination high-dose thiotepa (T) and etoposide (E)-based regimens in pediatric and adult patients with high-risk or recurrent primary brain tumors. Thirty-one patients (13 children and 18 adults) with brain tumors were treated with high-dose chemotherapy: 19 with BCNU (B) and TE (BTE regimen), and 12 with carboplatin (C) and TE (CTE regimen). Patients received growth factors and hematopoietic support with marrow (n = 15), peripheral blood progenitor cells (PBPC) (n = 11) or both (n = 5). The 100 day toxic mortality rate was 3% (1/31). Grade III/IV toxicities included mucositis (58%), hepatitis (39%) and diarrhea (42%). Five patients had seizures and two had transient encephalopathy (23%). All patients had neutropenic fever and all pediatric patients required hyperalimentation. Median time to engraftment with absolute neutrophil count (ANC) >0.5 x 10(9)/l was 11 days (range 8-37 days). Time to ANC engraftment was significantly longer (P = 0.0001) in patients receiving marrow (median 14 days, range 10-37) than for PBPC (median 9.5 days, range 8-10). Platelet engraftment >50 x 10(9)/l was 24 days (range 14-53 days) in children. In adults, platelet engraftment >20 x 10(9)/l was 12 days (range 9-65 days). In 11 patients supported with PBPC, there was a significant inverse correlation between CD34+ dose and days to ANC (rho = -0.87, P = 0.009) and platelet engraftment (rho = -0.85, P = 0.005), with CD34+ dose predicting time to engraftment following HDC. Overall, 30% of evaluable patients (7/24) had a complete response (CR) (n = 3) or partial response (PR) (n = 4). Median time to tumor progression (TTP) was 7 months, with an overall median survival of 12 months. These TE-based BCNU or carboplatin three-drug combination HDC regimens are safe and tolerable with promising response rates in both children and older adults.

Efficacy of macrolides used in combination with ethambutol, with or without other drugs, against Mycobacterium avium within human macrophages.

The activities of clarithromycin or roxithromicin used in combination with other antimicrobial drugs were tested in human macrophages experimentally infected with 23 strains of Mycobacterium avium. Overall, clarithromycin-ethambutol-rifampicin was the most active combination tested. The reduction in intracellular viable bacilli was found to be more than 1 log(10) for 95% and more than 2 logs(10) for 65% of the strains. The second most active combination was roxithromycin-ethambutol-rifampicin, which was found to be bactericidal for about 80% and highly bactericidal for 20% of the strains. Others combinations were only bacteriostatic or weakly bactericidal for many of the strains. The addition of a third drug did not necessarily promote enhanced bacterial killing inside the macrophage.

Rapid dose calculations for stereotactic radiosurgery.

A three-dimensional dose calculation algorithm is described for stereotactic radiosurgery using multiple noncoplanar beam arcs. Precalculated dose libraries of 20-deg arc segments, or mini arcs, are stored in computer memory which permits rapid calculation of complete, high resolution, three-dimensional isodose distributions and dose volume histograms. Three-dimensional patient contours and target volumes are obtained from CT scans and angiographic x rays. Rapid dose calculations are made possible by the use of arc libraries and an improved algorithm for mapping beam doses to the dose calculation grid. This permits more flexibility in designing optimum treatment plans, as five-six complete plans can be generated in less than 1 h. Thus many possible treatment options can be tested in the 3-4-h time period typically available in stereotactic procedures between CT scanning and treatment.

Intracerebral solitary plasmacytoma.

We report a rare occurrence of intraparenchymal plasmacytoma and review the literature. The clonal nature of the neoplasm is demonstrated by immunohistochemical and molecular techniques. The importance of the latter techniques in ruling out other pathological entities is stressed.

Radiosurgery for the treatment of recurrent central neurocytomas.

OBJECTIVE: Central neurocytomas are benign neoplasms with neuronal differentiation typically located in the lateral ventricles of young adults. Although the treatment of choice is complete surgical excision, patients may experience local recurrence. Adjuvant therapy for patients with residual or recurrent tumor has included reoperation, radiotherapy, or chemotherapy. To avoid the side effects of conventional radiotherapy in young patients, we present a series of patients with clear evidence of tumor progression who were treated with gamma knife radiosurgery. METHODS: Four patients (ages 20-49 yr; mean, 28 yr) who presented with an intraventricular mass on magnetic resonance imaging scans and underwent craniotomy for tumor resection were reviewed retrospectively. Histopathological analysis confirmed central neurocytoma in all cases. Each patient was followed up clinically and radiographically with serial magnetic resonance imaging. When radiographic signs of tumor progression were evident, patients were treated with radiosurgery. RESULTS: Complete radiographic tumor resection was achieved in all patients. There were no major postoperative complications. Local tumor progression was detected on magnetic resonance imaging scans 9 to 25 months after surgery (median, 17.5 mo). All patients achieved complete response to radiosurgery with reduction in tumor size. There have been no complications from radiosurgery. Follow-up ranged from 12 to 28 months (mean, 16.5 mo) after radiosurgery, and from 24 to 84 months (mean, 54.5 mo) after initial presentation. CONCLUSION: Radiosurgery with the gamma knife unit provides safe and effective adjuvant therapy after surgical resection of central neurocytomas. Radiosurgery may eliminate the need for reoperation and avoid the possible long-term side effects from conventional radiotherapy in young patients.

The effect of arteriovenous malformation resection on cerebrovascular reactivity to carbon dioxide.

To investigate the cerebral hemodynamic changes associated with obliteration of arteriovenous malformations (AVMs), we studied 26 patients undergoing total microsurgical AVM resection during isoflurane and N2/O2 anesthesia. Detectors were placed 5 to 6 cm from the margin of the lesion and in a homologous contralateral position. Cerebral blood flow (CBF) was measured using the intravenous xenon-133 technique before and after AVM resection, during both hypocapnia and normocapnia at each stage. Intraoperative changes in CBF were related to a risk score system based on the patient's history and preoperative angiograms. Seven otherwise healthy patients undergoing spinal surgery were studied to control for anesthetic effects. Patient demographic and clinical data for the AVM group conformed to the expected strata of a large AVM population. The CBF increased after excision (22 +/- 1 ml/100 g/min before excision to 30 +/- 2 ml/100 g/min after excision; mean +/- SE, n = 25, P less than 0.002) without a hemispheric difference. CO2 reactivity increased slightly after excision (4.2 +/- 0.3% change/mm Hg before excision to 4.7 +/- 0.3% change/mm Hg after excision; n = 14, P less than 0.02). The baseline CBF and CO2 reactivity were not different from the control group. There was a weak correlation between the risk score and the percentage of change in the ipsilateral CBF, with a trend for the patients with the lowest risk to have the lowest CBF changes after resection. There was no relationship between CO2 reactivity and risk grade. None of the patients awoke from anesthesia with unexpected neurological deficits. The highest CBF increases were associated with postoperative brain swelling in one patient and fatal intracerebral hemorrhage in another. Both patients had normal CO2 reactivity before excision. One patient suffered postoperative intracerebral hemorrhage, attributable to technical problems, and had no increase in CBF. We conclude that, with an acute increase in the arteriovenous pressure gradient (and cerebral perfusion pressure) that results from shunt obliteration, there is an immediate global effect of AVM resection to increase CBF. Cerebrovascular reactivity to CO2 remains intact both before and after excision.