First demonstration of velocity selective recording from the pig vagus using a nerve cuff shows respiration afferents.

Neural interfaces have great potential to treat disease and disability by modulating the electrical signals within the nervous system. However, whilst neural stimulation is a well-established technique, current neural interfaces are limited by poor recording ability. Low signal amplitudes necessitate the use of highly invasive techniques that divide or penetrate the nerve, and as such are unsuitable for chronic implantation. In this paper, we present the first application of the velocity selective recording technique to the detection of respiration activity in the vagus nerve, which is involved with treatments for epilepsy, depression, and rheumatoid arthritis. Further, we show this using a chronically implantable interface that does not divide the nerve. We also validate our recording setup using electrical stimulation and we present an analysis of the recorded signal amplitudes. The recording interface was formed from a cuff containing ten electrodes implanted around the intact right vagus nerve of a Danish Landrace pig. Nine differential amplifiers were connected to adjacent electrodes, and the resulting signals were processed to discriminate neural activity based on conduction velocity. Despite the average single channel signal-to-noise ratio of - 5.8 dB, it was possible to observe distinct action potentials travelling in both directions along the nerve. Further, contrary to expectation given the low signal-to-noise ratio, we have shown that it was possible to identify afferent neural activity that encoded respiration. The significance of this is the demonstration of a chronically implantable method for neural recording, a result that will transform the capabilities of future neuroprostheses.

An experimental demonstration of a new type of proton computed tomography using a novel silicon tracking detector.

PURPOSE: Radiography and tomography using proton beams promise benefit to image guidance and treatment planning for proton therapy. A novel proton tracking detector is described and experimental demonstrations at a therapy facility are reported. A new type of proton CT reconstructing relative "scattering power" rather than "stopping power" is also demonstrated. Notably, this new type of imaging does not require the measurement of the residual energies of the protons. METHODS: A large area, silicon microstrip tracker with high spatial and temporal resolution has been developed by the Proton Radiotherapy Verification and Dosimetry Applications consortium and commissioned using beams of protons at iThemba LABS, Medical Radiation Department, South Africa. The tracker comprises twelve planes of silicon developed using technology from high energy physics with each plane having an active area of ∼10 × 10 cm segmented into 2048 microstrips. The tracker is organized into four separate units each containing three detectors at 60° to one another creating an x-u-v coordinate system. Pairs of tracking units are used to reconstruct vertices for protons entering and exiting a phantom containing tissue equivalent inserts. By measuring the position and direction of each proton before and after the phantom, the nonlinear path for each proton through an object can be reconstructed. RESULTS: Experimental results are reported for tracking the path of protons with initial energies of 125 and 191 MeV. A spherical phantom of 75 mm diameter was imaged by positioning it between the entrance and exit detectors of the tracker. Positions and directions of individual protons were used to create angular distributions and 2D fluence maps of the beam. These results were acquired for 36 equally spaced projections spanning 180°, allowing, for the first time, an experimental CT image based upon the relative scattering power of protons to be reconstructed. CONCLUSIONS: Successful tracking of protons through a thick target (phantom) has demonstrated that the tracker discussed in this paper can provide the precise directional information needed to perform proton radiography and tomography. When synchronized with a range telescope, this could enable the reconstruction of proton CT images of stopping power. Furthermore, by measuring the deflection of many protons through a phantom, it was demonstrated that it is possible to reconstruct a new kind of CT image (scattering power) based upon this tracking information alone.

A new silicon tracker for proton imaging and dosimetry.

For many years, silicon micro-strip detectors have been successfully used as tracking detectors for particle and nuclear physics experiments. A new application of this technology is to the field of particle therapy where radiotherapy is carried out by use of charged particles such as protons or carbon ions. Such a treatment has been shown to have advantages over standard x-ray radiotherapy and as a result of this, many new centres offering particle therapy are currently under construction around the world today. The Proton Radiotherapy, Verification and Dosimetry Applications (PRaVDA) consortium are developing instrumentation for particle therapy based upon technology from high-energy physics. The characteristics of a new silicon micro-strip tracker for particle therapy will be presented. The array uses specifically designed, large area sensors with technology choices that follow closely those taken for the ATLAS experiment at the HL-LHC. These detectors will be arranged into four units each with three layers in an x-u-v configuration to be suitable for fast proton tracking with minimal ambiguities. The sensors will form a tracker capable of tracing the path of ~200 MeV protons entering and exiting a patient allowing a new mode of imaging known as proton computed tomography (pCT). This will aid the accurate delivery of treatment doses and in addition, the tracker will also be used to monitor the beam profile and total dose delivered during the high fluences used for treatment. We present here details of the design, construction and assembly of one of the four units that will make up the complete tracker along with its characterisation using radiation tests carried out using a 90Sr source in the laboratory and a 60 MeV proton beam at the Clatterbridge Cancer Centre.

A new method for spike extraction using velocity selective recording demonstrated with physiological ENG in Rat.

BACKGROUND: This paper describes a series of experiments designed to verify a new method of electroneurogram (ENG) recording that enables the rate of neural firing within prescribed bands of propagation velocity to be determined in real time. Velocity selective recording (VSR) has been proposed as a solution to the problem of increasing the information available from an implantable neural interface (typically with electrodes in circumferential nerve cuffs) and has been successful in transforming compound action potentials into the velocity domain. NEW METHOD: The new method extends VSR to naturally-evoked (physiological) ENG in which the rate of neural firing at particular velocities is required in addition to a knowledge of the velocities present in the recording. RESULTS: The experiments, carried out in rats required individual spikes to be distinct and non-overlapping, which could be achieved by a microchannel or small-bore cuff. In these experiments, strands of rat nerve were laid on ten hook electrodes in oil to demonstrate the principle. COMPARISON WITH EXISTING METHOD: The new method generates a detailed overview of the firing rates of neurons based on their conduction velocity and direction of propagation. In addition it allows real time working in contrast to existing spike sorting methods using statistical pattern processing techniques. CONCLUSIONS: Results show that by isolating neural activity based purely on conduction velocity it was possible to determine the onset of direct cutaneous stimulation of the L5 dermatome.

Proton tracking for medical imaging and dosimetry.

For many years, silicon micro-strip detectors have been successfully used as tracking detectors for particle and nuclear physics experiments. A new application of this technology is to the field of particle therapy, where radiotherapy is carried out by use of charged particles such as protons or carbon ions. Such a treatment has been shown to have advantages over standard x-ray radiotherapy and as a result of this, many new centres offering particle therapy are currently under construction - including two in the U.K.. The characteristics of a new silicon micro-strip detector based system for this application will be presented. The array uses specifically designed large area sensors in several stations in an x-u-v co-ordinate configuration suitable for very fast proton tracking with minimal ambiguities. The sensors will form a tracker capable of giving information on the path of high energy protons entering and exiting a patient. This will allow proton computed tomography (pCT) to aid the accurate delivery of treatment dose with tuned beam profile and energy. The tracker will also be capable of proton counting and position measurement at the higher fluences and full range of energies used during treatment allowing monitoring of the beam profile and total dose. Results and initial characterisation of sensors will be presented along with details of the proposed readout electronics. Radiation tests and studies with different electronics at the Clatterbridge Cancer Centre and the higher energy proton therapy facility of iThemba LABS in South Africa will also be shown.

Novel role for the transient receptor potential channel TRPM2 in prostate cancer cell proliferation.

We have identified a novel function for a member of the transient receptor potential (TRP) protein super-family, TRPM2, in prostate cancer cell proliferation. TRPM2 encodes a non-selective cation-permeable ion channel. We found that selectively knocking down TRPM2 with the small interfering RNA technique inhibited the growth of prostate cancer cells but not of non-cancerous cells. The subcellular localization of this protein is also remarkably different between cancerous and non-cancerous cells. In BPH-1 (benign), TRPM2 protein is homogenously located near the plasma membrane and in the cytoplasm, whereas in the cancerous cells (PC-3 and DU-145), a significant amount of the TRPM2 protein is located in the nuclei in a clustered pattern. Furthermore, we have found that TRPM2 inhibited nuclear ADP-ribosylation in prostate cancer cells. However, TRPM2 knockdown-induced inhibition of proliferation is independent of the activity of poly(ADP-ribose) polymerases. We conclude that TRPM2 is essential for prostate cancer cell proliferation and may be a potential target for the selective treatment of prostate cancer.

AVP (4-8) improves concept learning in PFC-damaged but not hippocampal-damaged rats.

A position reversal task was used to test the memory-enhancing effects of the arginine vasopressin analog [pGlu4, Cyt6] AVP (4-8) at a dose of 1.5 microg/kg. Rats received either sham operations (SHM), medial prefrontal cortex lesions (PFC), or hippocampal lesions (HIP). The peptide was administered daily, via s.c. injection, 30 min prior to training to half of the animals in each group. As expected, all animals performed equally well on the initial position habit and the first reversal. Overall, it was found that AVP (4-8)-treated animals performed significantly better across trials than saline (SAL)-treated animals. Further analysis showed that PFC animals that received AVP (4-8) (PFC+AVP) performed significantly better (at the level of controls) across trials than saline-treated PFC (PFC+SAL) animals. Sham animals that received the AVP (4-8) analog (SHM+AVP) only showed significant improvement on the last two reversals when compared to the sham saline-treated animals (SHM+SAL), which was likely due to a ceiling effect as performance reached high levels early in the reversal task. Trial 2 analysis across reversals revealed enhanced cognitive abilities in both sham groups (SHM+SAL, SHM+AVP) and the PFC+AVP group, but not in the PFC+SAL, HIP+AVP or the HIP+SAL groups. Hippocampal lesioned animals performed poorly on the task and injections of AVP (4-8) did not improve their performance. It is thus concluded that AVP (4-8) enhanced the acquisition of concept learning (win-stay/loose-shift) in this paradigm in PFC-damaged animals and ameliorated the perseverance habit that is often seen in PFC animals on this task. It is suggested that AVP (4-8) might have an enhancing effect on general cognitive abilities that is not limited to memory processes.

Cloning of a receptor for amphibian [Phe13]bombesin distinct from the receptor for gastrin-releasing peptide: identification of a fourth bombesin receptor subtype (BB4).

Bombesin is a tetradecapeptide originally isolated from frog skin and demonstrated to have a wide range of actions in mammals. Based on structural homology and similar biological activities, gastrin-releasing peptide (GRP) has been considered the mammalian equivalent of bombesin. We previously reported that frogs have both GRP and bombesin, which therefore are distinct peptides. We now report the cloning of a bombesin receptor subtype (BB4) that has higher affinity for bombesin than GRP. PCR was used to amplify cDNAs related to the known bombesin receptors from frog brain. Sequence analysis of the amplified cDNAs revealed 3 classes of receptor subtypes. Based on amino acid homology, two classes were clearly the amphibian homologs of the GRP and neuromedin B receptors. The third class was unusual and a full-length clone was isolated from a Bombina orientalis brain cDNA library. Expression of the receptor in Xenopus oocytes demonstrated that the receptor responded to picomolar concentrations of [Phe13]-bombesin, the form of bombesin most prevalent in frog brain. The relative rank potency of bombesin-like peptides for this receptor was [Phe13]bombesin > [Leu13]bombesin > GRP > neuromedin B. In contrast, the rank potency for the GRP receptor is GRP > [Leu13]bombesin > [Phe13]bombesin > neuromedin B. Transient expression in CHOP cells gave a Ki for [Phe13]bombesin of 0.2 nM versus a Ki of 2.1 nM for GRP. Distribution analysis showed that this receptor was expressed only in brain, consistent with the distribution of [Phe13]-bombesin. Thus, based on distribution and affinity, this bombesin receptor is the receptor for [Phe13]bombesin. Phylogenetic analysis suggests that this receptor separated prior to separation of the GRP and neuromedin B receptors; thus, BB4 receptors and their cognate ligands may also exist in mammals.

A 5' portion of the ICAM-1 gene confers tissue-specific differential expression levels and cytokine responsiveness.

Intercellular adhesion molecule-1 (ICAM-1), a cell-adhesion molecule critically involved in leukocyte trafficking and adherence, displays tissue-specific and cytokine-specific expression profiles. Although human dermal microvascular endothelial cells (HDMEC) constitutively express ICAM-1, keratinocytes (HK) do not. Interleukin-1 (IL-1) upregulates ICAM-1 expression in HDMEC, but fails to do so in either HK or A431, a human squamous carcinoma cell line, even though both have IL-1 receptors and express ICAM-1 on exposure to other cytokines. We have previously characterized a human ICAM-1 genomic clone that contains the 5' flanking transcriptional regulatory region. To test the hypothesis that tissue- and cytokine-specific ICAM-1 gene expression results from the interaction of constitutive and inducible tissue-specific trans-acting factors with distinct cis-elements of the ICAM-1 gene, various ICAM-1-based reporter gene (CAT) plasmids were constructed. Transcriptional activity of these various constructs was assessed after transient transfection into HDMEC and A431. A critical ICAM-1 region was identified that conferred enhanced expression of CAT in HDMEC and suppressed expression of CAT in A431. This same region further enhanced CAT expression in transfected HDMEC treated with IL-1 alpha, yet no such enhancement was seen with IL-1 treatment of identically transfected A431. However, treatment of A431 transfectants with IFN gamma did result in enhanced CAT expression, demonstrating reversal of A431 cell context suppression of the ICAM-1-based reporter gene construct. These data implicate the existence of both tissue- and cytokine-specific responsive elements in the 5' flanking region of the ICAM-1 gene and demonstrate that regulatory effects directed by such elements are dependent upon their cellular context. Moreover, they provide the basis for identification of specific cis-acting genetic elements, the trans-acting factors with which they interact, and the molecular mechanisms by which they regulate transcription of the ICAM-1 gene.

Documentation of cost savings from decentralized clinical pharmacy services at a community hospital.

A pilot program designed to justify the costs of clinical pharmacy services through the use of workload documentation cards is described. At this community hospital, defining a philosophy of care was the first step in developing and implementing decentralized services. A patient-specific care model was chosen, and principles of patient-oriented service were outlined. Daily workload documentation cards were designed for recording pharmacist activities; distribution functions were noted on one side, clinical activities on the other. Direct cost savings that could be attributed to the clinical pharmacists' drug therapy recommendations were quantified and recorded on a second form. Sixty-three beds in four hospital units were chosen as sites of the pilot effort. At the end of the six-month study, an analysis of the cost-savings forms documented that clinical pharmacist activities produced an average savings of $1.49 per patient day. The break-even point at which pharmacist salary expenses would equal direct cost savings was determined to be one clinical pharmacist per 80 patient beds. A request to expand clinical services at the hospital was granted. By documenting clinical and distributive activities on a simple form and quantifying the savings associated with clinical interventions, this pilot program demonstrated the cost-effectiveness of clinical pharmacy services.

Fabrication of a teaching aid for dental soft tissue management and suturing.

A technique for fabrication of a model to aid in teaching surgical management and suturing is presented. The model, which simulates dentition, supporting periodontium, and gingival soft tissue, can be made inexpensively in a dental laboratory.

Liquid chromatography at 3-methoxy-4-hydroxyphenylethylene glycol in urine with fluorescence detection.

We describe a liquid-chromatographic procedure for determining low concentrations of 3-methoxy-4-hydroxyphenylethylene glycol in urine. After liquid-liquid extraction and cleanup of the sample, an aliquot of the extract is injected onto a reversed-phase chromatographic column, with isocratic elution with an acetonitrile/acetate buffer mobile phase. An on-line fluorescence detector is used for measuring the natural fluorescence of the compound. The method gives a relatively clean extract, which is suitable for measuring the less-than-normal concentrations associated with mentally depressed patients. Although a liquid-chromatographic technique has been recently described for measuring this compound in urine, the method involves electrochemical detection, which may not be available in many clinical laboratories, and, because of its nonspecificity, the method is only suitable for detecting the increased amounts of 3-methoxy-4-hydroxyphenylethylene glycol excreted by patients with pheochromocytoma.

Determination of urinary placental estriol by reversed-phase liquid chromatography with fluorescence detection.

Ww describe a liquid-chromatographic procedure for determining urinary estriol concentrations. The urine sample, after enzymatic hydrolysis to free the conjugated estrogen, is extracted with ether, and an aliquot of the resulting extraction residue is injected into the liquid chromatograph. Sample components are separated with a reversed-phase C18 column and isocratic elution with an acetonitrile/water mobile phase. Using a far-ultraviolet excitation wavelength, we measure the natural fluorescence of the eluted estrogen with a fluorescence detector. The procedure provides excellent sensitivity for determing near-term pregnancy concentrations of urinary estriol. The selectivity of the method limits the effect of potentially interfering compounds.