CT-compatible system for stereotactic biopsy and brachytherapy of infratentorial tumors

Teletherapy of nonresectable radiosensitive brain tumors is the mainstay of adjunctive treatment. In the past two decades brachytherapy has begun to play an ever-increasing role, particularly on the European continent. Yet this attention has been addressed almost exclusively to lesions of the supratentorial space. This article describes modifications of the Riechert-Mundinger stereotactic system which were made by one of us (P.D.) to allow an unencumbered yet precisely computerized stereotactic approach to posterior fossa lesions for biopsy and interstitial radiation with iridium 192. A case report is described to illustrate the technical details involved in such an undertaking.     

Host-supplied connective tissue as a guide for proliferating tumor cells in human tumor xenografts

The morphologic alterations of 7 human tumors of different origin and various histologic types, heterotransplanted to athymic nude mice, were investigated in the present study. Constant patterns of histologic and ultrastructural changes were observed in all 7 tumors. Following the initial dying of most inoculated tumor cells, host-supplied inflammatory cells invaded the xenografts and phagocytosed necrotic tumor cells. Fibroblasts which vivaciously produced collagenous material invaded the xenografts and built up solid strands of connective tissue which tightly contacted surviving tumor cells. These stands were used as guide-rails for ingrowing blood vessels. Immediately after their immigration, the first mitoses of tumor cells occurred in close proximity to capillary-conducting strands of connective tissue resulting in a revival of tumor cell proliferation near to the fibrous cords and a spreading of newly formed tumor cells along the strands of connective tissue. These results point to the host-supplied connective tissue as playing an important role for tumor proliferation and local tumor expansion.     

Cytology of neuroectodermal tumors of the brain in crush preparations. A review of 56 cases of deep-seated tumors sampled by CT-guided stereotactic needle biopsy

Fifty-six brain tumors of neuroectodermal origin were sampled by computed tomographic stereotactic needle biopsy. Crush preparations prepared from tiny tissue fragments displayed distinctive cytologic characteristics of different tumor types in 77% of the cases. The adjunctival value of crush preparations to frozen section diagnosis is discussed, and the cytologic features of different types of neuroectodermal brain tumors in crush preparations are illustrated.     

Proton-transfer-reaction mass spectrometry as a new tool for real time analysis of root-secreted volatile organic compounds in Arabidopsis

Plant roots release about 5% to 20% of all photosynthetically-fixed carbon, and as a result create a carbon-rich environment for numerous rhizosphere organisms, including plant pathogens and symbiotic microbes. Although some characterization of root exudates has been achieved, especially of secondary metabolites and proteins, much less is known about volatile organic compounds (VOCs) released by roots. In this communication, we describe a novel approach to exploring these rhizosphere VOCs and their induction by biotic stresses. The VOC formation of Arabidopsis roots was analyzed using proton-transfer-reaction mass spectrometry (PTR-MS), a new technology that allows rapid and real time analysis of most biogenic VOCs without preconcentration or chromatography. Our studies revealed that the major VOCs released and identified by both PTR-MS and gas chromatography-mass spectrometry were either simple metabolites, ethanol, acetaldehyde, acetic acid, ethyl acetate, 2-butanone, 2,3,-butanedione, and acetone, or the monoterpene, 1,8-cineole. Some VOCs were found to be produced constitutively regardless of the treatment; other VOCs were induced specifically as a result of different compatible and noncompatible interactions between microbes and insects and Arabidopsis roots. Compatible interactions of Pseudomonas syringae DC3000 and Diuraphis noxia with Arabidopsis roots resulted in the rapid release of 1,8-cineole, a monoterpene that has not been previously reported in Arabidopsis. Mechanical injuries to Arabidopsis roots did not produce 1,8-cineole nor any C6 wound-VOCs; compatible interactions between Arabidopsis roots and Diuraphis noxia did not produce any wound compounds. This suggests that Arabidopsis roots respond to wounding differently from above-ground plant organs. Trials with incompatible interactions did not reveal a set of compounds that was significantly different compared to the noninfected roots. The PTR-MS method may open the way for functional root VOC analysis that will complement genomic investigations in Arabidopsis.     

Use of hair as a biopsy tissue for calcium

Experimental and literature values for hair calcium levels were evaluated to identify their physiological significance. The distribution of values obtained from different populations indicates that the calcium content of scalp hair reflects calcium metabolism in the body. Correlations between the hair calcium concentrations from different anatomical sites support this indication.     

An integrated method for reproducible and accurate image-guided stereotactic cranial irradiation of brain tumors using the small animal radiation research platform

Preclinical studies of cranial radiation therapy (RT) using animal brain tumor models have been hampered by technical limitations in the delivery of clinically relevant RT. We established a bioimageable mouse model of glioblastoma multiforme (GBM) and an image-guided radiation delivery system that facilitated precise tumor localization and treatment and which closely resembled clinical RT. Our novel radiation system makes use of magnetic resonance imaging (MRI) and bioluminescent imaging (BLI) to define tumor volumes, computed tomographic (CT) imaging for accurate treatment planning, a novel mouse immobilization system, and precise treatments delivered with the Small Animal Radiation Research Platform. We demonstrated that, in vivo, BLI correlated well with MRI for defining tumor volumes. Our novel restraint system enhanced setup reproducibility and precision, was atraumatic, and minimized artifacts on CT imaging used for treatment planning. We confirmed precise radiation delivery through immunofluorescent analysis of the phosphorylation of histone H2AX in irradiated brains and brain tumors. Assays with an intravenous near-infrared fluorescent probe confirmed that radiation of orthografts increased disruption of the tumor blood-brain barrier (BBB). This integrated model system, which facilitated delivery of precise, reproducible, stereotactic cranial RT in mice and confirmed RT's resultant histologic and BBB changes, may aid future brain tumor research.     

FDTD analysis of a noninvasive hyperthermia system for brain tumors

ABSTRACT: BACKGROUND: Hyperthermia is considered one of the new therapeutic modalities for cancer treatment and is based on the difference in thermal sensitivity between healthy tissues and tumors. During hyperthermia treatment, the temperature of the tumor is raised to 40--4[DEGREE SIGN]C for a definite period resulting in the destruction of cancer cells. This paper investigates design, modeling and simulation of a new non-invasive hyperthermia applicator system capable of effectively heating deep seated as well as superficial brain tumors using inexpensive, simple, and easy to fabricate components without harming surrounding healthy brain tissues. METHODS: The proposed hyperthermia applicator system is composed of an air filled partial half ellipsoidal chamber, a patch antenna, and a head model with an embedded tumor at an arbitrary location. The irradiating antenna is placed at one of the foci of the hyperthermia chamber while the center of the brain tumor is placed at the other focus. The finite difference time domain (FDTD) method is used to compute both the SAR patterns and the temperature distribution in three different head models due to two different patch antennas at a frequency of 915 MHz. RESULTS: The obtained results suggest that by using the proposed noninvasive hyperthermia system it is feasible to achieve sufficient and focused energy deposition and temperature rise to therapeutic values in deep seated as well as superficial brain tumors without harming surrounding healthy tissue. CONCLUSIONS: The proposed noninvasive hyperthermia system proved suitable for raising the temperature in tumors embedded in the brain to therapeutic values by carefully selecting the systems components. The operator of the system only needs to place the center of the brain tumor at a pre-specified location and excite the antenna at a single frequency of 915 MHz. Our study may provide a basis for a clinical applicator prototype capable of heating brain tumors.     

Generic method for quantification of FLAG-tagged fusion proteins by a real time biosensor

Availability of rapid quantitative protein-expression analysis is often the bottleneck in high throughput screening applications. A real time biosensor was employed to establish a quantitative assay for FLAG fusion proteins using FLAG-tagged bacterial alkaline phosphatase as standard. A range of FLAG-tagged bacterial alkaline phosphatase concentrations were injected over the anti-FLAG M2 antibody surface of the biosensor and used as standards to determine the concentration of different FLAG-tagged proteins with a molecular mass of 18.1 kDa respectively 49.3 kDa from yeast culture supernatants. The M2 immobilized chip was found to retain binding capacity following regeneration for at least 120 cycles. This real time biosensor method allows the quantitation of proteins from culture supernatants using a calibration curve obtained with a different protein. Further benefits include the short assay time of approximately 5 min, the small amount of sample required (35 microl per injection) and the ability to monitor the binding event in real time.     

Decrease in human growth hormone (HGH) levels during transsphenoidal surgery for acromegaly as a guide for prognosis

To evaluate the clinical significance of human growth hormone (HGH) dynamics during transsphenoidal microsurgery for acromegaly, serial HGH levels during the surgery were compared with the post-operative basal HGH levels in 15 acromegalic patients, retrospectively. In all patients, in whom the HGH level immediately after tumor resection was reduced below 5 ng/ml or the decreasing rate which stood for the magnitude of decrease of HGH during resection procedure was above 80%, postoperative permanent HGH levels fell to below 5 ng/ml, namely, within the normal range. The rapid radioimmunoassay (RIA) of HGH was developed by the use of high affinity antibody in order to inform the surgeons of plasma HGH levels quickly during the surgery. It is now possible to know HGH levels about 1 hour after submitting the samples. It was verified that HGH levels measured in the rapid RIA correlated well with those obtained in the conventional way. The rapid RIA method was applied to 6 patients and the correlation between HGH levels during the surgery and post operative levels was also studied prospectively. The results were essentially identical to those in a retrospective study. It was suggested that the HGH level immediately after tumor resection and the extent of the decrease in HGH during the resection procedure were good indicators of the prognosis of surgical results in acromegaly and the rapid RIA method was useful in order to judge HGH levels quickly during the surgery.     

Development of a perchlorate reductase-based biosensor for real time analysis of perchlorate in water

Perchlorate (ClO4-) contamination of ground water is a widespread problem in the U.S., which can adversely affect human health and wildlife. Current methods for detecting and quantifying ClO4- in water are time consuming, expensive and sometimes subject to complex procedures. This study reports the construction of a ClO4- reductase-based biosensor for rapid determination of ClO4- in water. Using a 3 mm GCE (glass carbon electrode), a ClO4- sensing bio-electrode was constructed by coating an aliquot of a Dechlorosoma sp. ClO4- reductase on nafion (ion-exchange matrix) layer pre-coated on the polished surface of the GCE. The response time to ClO4- was approximately 111+/-28 s. Kinetic evaluation of the sensor response to ClO4- revealed linear increases (r2>99%) in 10 min with k values of 10.3, 24.2, 33.9 and 48.2 at 25, 50, 75 and 100 microg/L, respectively. A strong linear correlation was established between biosensor response (nA) and ion-chromatography conductivity readings (microS). Biosensor response to ClO4- was maximal at applied potential range of -0.6 to -1.0 V. ClO4- reduction was maximal in the range of 7.6 to 8.0. The ClO4- biosensor was significantly stable after repeated use (24 analyses conducted on day 1 over a 10-h period at room temperature). This study indicates great potential for the development of a portable biosensor for real time analysis of ClO4- in water.     

Development of a real time polymerase chain reaction for quantitation of Schistosoma mansoni DNA

This report describes the development of a SYBR Green I based real time polymerase chain reaction (PCR) protocol for detection on the ABI Prism 7000 instrument. Primers targeting the gene encoding the SSU rRNA were designed to amplify with high specificity DNA from Schistosoma mansoni, in a real time quantitative PCR system. The limit of detection of parasite DNA for the system was 10 fg of purified genomic DNA, that means less than the equivalent to one parasite cell (genome ~580 fg DNA). The efficiency was 0.99 and the correlation coefficient (R(2)) was 0.97. When different copy numbers of the target amplicon were used as standards, the assay could detect at least 10 copies of the specific target. The primers used were designed to amplify a 106 bp DNA fragment (Tm 83 degrees C). The assay was highly specific for S. mansoni, and did not recognize DNA from closely related non-schistosome trematodes. The real time PCR allowed for accurate quantification of S. mansoni DNA and no time-consuming post-PCR detection of amplification products by gel electrophoresis was required. The assay is potentially able to quantify S. mansoni DNA (and indirectly parasite burden) in a number of samples, such as snail tissue, serum and feces from patients, and cercaria infested water. Thus, these PCR protocols have potential to be used as tools for monitoring of schistosome transmission and quantitative diagnosis of human infection.     

Using BRAFV600E as a marker of autophagy dependence in pediatric brain tumors

Autophagy inhibition is a potential therapeutic strategy in central nervous system (CNS) tumors. The BRAF^V600E mutation is known to affect autophagy. Our studies indicate CNS tumor cells with BRAF^V600E mutant cells (but not wild type) display high rates of induced autophagy, are sensitive to autophagy inhibition, and display synergy when chloroquine is combined with the RAF kinase inhibitor vemurafenib or standard chemotherapeutics. Our studies also indicate chloroquine can improve vemurafenib sensitivity in intrinsically resistant cells and in a patient with induced-vemurafenib resistance. These findings suggest CNS tumors with BRAF^V600E are autophagy-dependent and that identification of BRAF^V600E may be a marker to identify pediatric patients with the best potential response to autophagy inhibition.     

Using BRAFV600E as a marker of autophagy dependence in pediatric brain tumors

Autophagy inhibition is a potential therapeutic strategy in central nervous system (CNS) tumors. The BRAF^V600E mutation is known to affect autophagy. Our studies indicate CNS tumor cells with BRAF^V600E mutant cells (but not wild type) display high rates of induced autophagy, are sensitive to autophagy inhibition, and display synergy when chloroquine is combined with the RAF kinase inhibitor vemurafenib or standard chemotherapeutics. Our studies also indicate chloroquine can improve vemurafenib sensitivity in intrinsically resistant cells and in a patient with induced-vemurafenib resistance. These findings suggest CNS tumors with BRAF^V600E are autophagy-dependent and that identification of BRAF^V600E may be a marker to identify pediatric patients with the best potential response to autophagy inhibition.     

Reaction time impairments in decision-making networks as a diagnostic marker for traumatic brain injuries and neurological diseases

The presence of diffuse Focal Axonal Swellings (FAS) is a hallmark cellular feature in many neurological diseases and traumatic brain injury. Among other things, the FAS have a significant impact on spike-train encodings that propagate through the affected neurons, leading to compromised signal processing on a neuronal network level. This work merges, for the first time, three fields of study: (i) signal processing in excitatory-inhibitory (EI) networks of neurons via population codes, (ii) decision-making theory driven by the production of evidence from stimulus, and (iii) compromised spike-train propagation through FAS. As such, we demonstrate a mathematical architecture capable of characterizing compromised decision-making driven by cellular mechanisms. The computational model also leads to several novel predictions and diagnostics for understanding injury level and cognitive deficits, including a key finding that decision-making reaction times, rather than accuracy, are indicative of network level damage. The results have a number of translational implications, including that the level of network damage can be characterized by the reaction times in simple cognitive and motor tests.     

Visualizing the store-operated channel complex assembly in real time: Identification of SERCA2 as a new member

Depletion of intracellular calcium stores leads to the activation of calcium influx via the so-called store-operated channels (SOCs). Recent evidence positions Orai proteins as the putative channels responsible for this process. The stromal interacting molecule (STIM1) has been recently identified as the calcium sensor located at the endoplasmic reticulum (ER), and responsible for communicating the deplete state of calcium stores to Orai at the plasma membrane (PM). However, recent experimental findings suggest that Orai and STIM1 are only part of a larger molecular complex required to modulate store-operated calcium entry (SOCE). In the present study we describe the assembly of the several of the components from the SOC complex in real-time, utilizing a novel imaging method. Using FRET imaging we show that under resting conditions (with calcium stores replenished) STIM1 travels continuously through the ER associated to the microtubule tracking protein, EB1. Upon depletion of the ER STIM1 dissociates from EB1 and aggregates into macromolecular complexes at the ER which includes the microsomal calcium ATPase. This association follows the assembly of Orai into macromolecular aggregates at the PM. We show that STIM1–Orai association follows a similar time course as that of Orai aggregation at the PM. During this last step of the process, calcium-selective, whole-cell inward currents developed, simultaneously. We show that this process is fully reversible. Replenishing intracellular calcium stores induces STIM1–Orai complex dissociation and shuts down inward currents. Under these conditions STIM1 re-associates to EB1, and reinitiates its travel through the ER.