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The Gemini Planet Imager Exoplanet Survey (GPIES) is a multiyear direct imaging survey of 600 stars to discover and characterize young Jovian exoplanets and their environments. We have developed an automated data architecture to process and index all data related to the survey uniformly. An automated and flexible data processing framework, which we term the Data Cruncher, combines multiple data reduction pipelines (DRPs) together to process all spectroscopic, polarimetric, and calibration data taken with GPIES. With no human intervention, fully reduced and calibrated data products are available less than an hour after the data are taken to expedite follow up on potential objects of interest. The Data Cruncher can run on a supercomputer to reprocess all GPIES data in a single day as improvements are made to our DRPs. A backend MySQL database indexes all files, which are synced to the cloud, and a front-end web server allows for easy browsing of all files associated with GPIES. To help observers, quicklook displays show reduced data as they are processed in real time, and chatbots on Slack post observing information as well as reduced data products. Together, the GPIES automated data processing architecture reduces our workload, provides real-Time data reduction, optimizes our observing strategy, and maintains a homogeneously reduced dataset to study planet occurrence and instrument performance.

We present new observations of the low-mass companion to HD 984 taken with the Gemini Planet Imager (GPI) as a part of the GPI Exoplanet Survey campaign. Images of HD 984 B were obtained in the J (1.12-1.3 μm) and H (1.50-1.80 μm) bands. Combined with archival epochs from 2012 and 2014, we fit the first orbit to the companion to find an 18 au (70-year) orbit with a 68% confidence interval between 14 and 28 au, an eccentricity of 0.18 with a 68% confidence interval between 0.05 and 0.47, and an inclination of 119°with a 68% confidence interval between 114°and 125°. To address the considerable spectral covariance in both spectra, we present a method of splitting the spectra into low and high frequencies to analyze the spectral structure at different spatial frequencies with the proper spectral noise correlation. Using the split spectra, we compare them to known spectral types using field brown dwarf and low-mass star spectra and find a best-fit match of a field gravity M6.5 ±1.5 spectral type with a corresponding temperature of K. Photometry of the companion yields a luminosity of log(Lbol/L⊙)=2.88 ± 0.07 dex with DUSTY models. Mass estimates, again from DUSTY models, find an age-dependent mass of 34 ±1 to 95 ±4 M Jup. These results are consistent with previous measurements of the object.

We present new spatially resolved astrometry and photometry from the Gemini Planet Imager of the inner binary of the young multiple star system V343 Normae, which is a member of the β Pictoris (β Pic) moving group. V343 Normae comprises a K0 and mid-M star in a ∼4.5 year orbit (AaAb) and a wide 10″ M5 companion (B). By combining these data with archival astrometry and radial velocities we fit the orbit and measure individual masses for both components of MAa = 1.10 ± 0.10 M⊙ and MAb = 0.290 ± 0.018 M⊙. Comparing to theoretical isochrones, we find good agreement for the measured masses and JHK band magnitudes of the two components consistent with the age of the β Pic moving group. We derive a model-dependent age for the β Pic moving group of 26 ±3 Myr by combining our results for V343 Normae with literature measurements for GJ 3305, which is another group member with resolved binary components and dynamical masses.

A principal scientific goal of the Gemini Planet Imager (GPI) is obtaining milliarcsecond astrometry to constrain exoplanet orbits. However, astrometry of directly imaged exoplanets is subject to biases, systematic errors, and speckle noise. Here, we describe an analytical procedure to forward model the signal of an exoplanet that accounts for both the observing strategy (angular and spectral differential imaging) and the data reduction method (Karhunen-Loève Image Projection algorithm). We use this forward model to measure the position of an exoplanet in a Bayesian framework employing Gaussian processes and Markov-chain Monte Carlo to account for correlated noise. In the case of GPI data on β Pic b, this technique, which we call Bayesian KLIP-FM Astrometry (BKA), outperforms previous techniques and yields 1σ errors at or below the one milliarcsecond level. We validate BKA by fitting a Keplerian orbit to 12 GPI observations along with previous astrometry from other instruments. The statistical properties of the residuals confirm that BKA is accurate and correctly estimates astrometric errors. Our constraints on the orbit of β Pic b firmly rule out the possibility of a transit of the planet at 10-σ significance. However, we confirm that the Hill sphere of β Pic b will transit, giving us a rare chance to probe the circumplanetary environment of a young, evolving exoplanet. We provide an ephemeris for photometric monitoring of the Hill sphere transit event, which will begin at the start of April in 2017 and finish at the end of January in 2018.

We present the discovery of a brown dwarf companion to the debris disk host star HR 2562. This object, discovered with the Gemini Planet Imager (GPI), has a projected separation of 20.3 ± 0.3 au (0.″618 ± 0. ″004) from the star. With the high astrometric precision afforded by GPI, we have confirmed, to more than 5?, the common proper motion of HR 2562B with the star, with only a month-long time baseline between observations. Spectral data in the J-, H-, and K-bands show a morphological similarity to L/T transition objects. We assign a spectral type of L7 ± 3 to HR 2562Band derive a luminosity of log(Lbol/L⊙) = -4.62 ± 0.12, corresponding to a mass of 30 ± 15 MJup from evolutionary models at an estimated age of the system of 300-900 Myr. Although the uncertainty in the age of the host star is significant, the spectra and photometry exhibit several indications of youth for HR 2562B. The source has a position angle that is consistent with an orbit in the same plane as the debris disk recently resolved with Herschel. Additionally, it appears to be interior to the debris disk. Though the extent of the inner hole is currently too uncertain to place limits on the mass of HR 2562B, future observations of the disk with higher spatial resolution may be able to provide mass constraints. This is the first brown-dwarf-mass object found to reside in the inner hole of a debris disk, offering the opportunity to search for evidence of formation above the deuterium burning limit in a circumstellar disk.

Directly detecting thermal emission from young extrasolar planets allows measurement of their atmospheric compositions and luminosities, which are influenced by their formation mechanisms. Using the Gemini Planet Imager, we discovered a planet orbiting the ~20-million-year-old star 51 Eridani at a projected separation of 13 astronomical units. Near-infrared observations show a spectrum with strong methane and water-vapor absorption. Modeling of the spectra and photometry yields a luminosity (normalized by the luminosity of the Sun) of 1.6 to 4.0 × 10(-6) and an effective temperature of 600 to 750 kelvin. For this age and luminosity, "hot-start" formation models indicate a mass twice that of Jupiter. This planet also has a sufficiently low luminosity to be consistent with the "cold-start" core-accretion process that may have formed Jupiter.

We present H-band observations of β Pic with the Gemini Planet Imager's (GPI's) polarimetry mode that reveal the debris disk between ∼0.″3 (6 AU) and ∼1.″7 (33 AU), while simultaneously detecting β Pic b. The polarized disk image was fit with a dust density model combined with a Henyey-Greenstein scattering phase function. The best-fit model indicates a disk inclined to the line of sight () with a position angle (PA) (slightly offset from the main outer disk, ), that extends from an inner disk radius of to well outside GPI's field of view. In addition, we present an updated orbit for β Pic b based on new astrometric measurements taken in GPI's spectroscopic mode spanning 14 months. The planet has a semimajor axis of , with an eccentricity The PA of the ascending node is offset from both the outer main disk and the inner disk seen in the GPI image. The orbital fit constrains the stellar mass of β Pic to Dynamical sculpting by β Pic b cannot easily account for the following three aspects of the inferred disk properties: (1) the modeled inner radius of the disk is farther out than expected if caused by β Pic b; (2) the mutual inclination of the inner disk and β Pic b is when it is expected to be closer to zero; and (3) the aspect ratio of the disk () is larger than expected from interactions with β Pic b or self-stirring by the disk's parent bodies.

We present the first results from the polarimetry mode of the Gemini Planet Imager (GPI), which uses anew integral field polarimetry architecture to provide high contrast linear polarimetry with minimal systematic biases between the orthogonal polarizations. We describe the design, data reduction methods, and performance of polarimetry with GPI. Point-spread function (PSF) subtraction via differential polarimetry suppresses unpolarized starlight by a factor of over 100, and provides sensitivity to circumstellar dust reaching the photon noise limit for these observations. in the case of the circumstellar disk around HR 4796A,GPI's advanced adaptive optics system reveals the disk clearly even prior to PSF subtraction. In polarized light, the disk is seen all the way in to its semi-minor axis for the first time. The disk exhibits surprisingly strong asymmetry in polarized intensity, with the west side ≳9 times brighter than the east side despite the fact that the east side is slightly brighter in total intensity. Based on a synthesis of the total and polarized intensities, we now believe that the west side is closer to us, contrary to most prior interpretations. Forward scattering by relatively large silicate dust particles leads to the strong polarized intensity on thewest side, and the ring must be slightly optically thick in order to explain the lower brightness in total intensity there. These findings suggest that the ring is geometrically narrow and dynamically cold, perhaps shepherded by larger bodies in the same manner as Saturn's Fring.

During the first-light run of the Gemini Planet Imager we obtained K-band spectra of exoplanets HR 8799 c and d. Analysis of the spectra indicates that planet d may be warmer than planet c. Comparisons to recent patchy cloud models and previously obtained observations over multiple wavelengths confirm that thick clouds combined with horizontal variation in the cloud cover generally reproduce the planets' spectral energy distributions. When combined with the 3 to 4 μm photometric data points, the observations provide strong constraints on the atmospheric methane content for both planets. The data also provide further evidence that future modeling efforts must include cloud opacity, possibly including cloud holes, disequilibrium chemistry, and super-solar metallicity.

We present the retinal plenoptoscope, a novel light field retinal imaging device designed to overcome many of the problems that limit the use of portable non-mydriatic fundus cameras, including image quality and lack of stereopsis. The design and prototype construction of this device is detailed and the ideal relationship between the eye pupil, system aperture stop and micro-image separation is investigated. A comparison of the theoretical entrance pupil size, multi-view baseline and depth resolution indicates that a higher degree of stereopsis is possible than with stereo fundus cameras. We also show that the effects of corneal backscatter on image quality can be removed through a novel method of glare identification and selective image rendering. This method is then extended to produce glare-free depth maps from densely estimated depth fields, creating representations of retinal topography from a single exposure. These methods are demonstrated on physical models and live human eyes using a prototype device based on a Lytro Illum consumer light field camera. The Retinal Plenoptoscope offers a viable, robust modality for non-mydriatic color and 3-D retinal imaging., Competing Interests: The authors declare that there are no conflicts of interest related to this article.

The Gemini Planet Imager's adaptive optics (AO) subsystem was designed specifically to facilitate high-contrast imaging. A definitive description of the system's algorithms and technologies as built is given. 564 AO telemetry measurements from the Gemini Planet Imager Exoplanet Survey campaign are analyzed. The modal gain optimizer tracks changes in atmospheric conditions. Science observations show that image quality can be improved with the use of both the spatially filtered wavefront sensor and linear-quadratic-Gaussian control of vibration. The error budget indicates that for all targets and atmospheric conditions AO bandwidth error is the largest term.

We have investigated using density functional theory the effect of fluorine termination of a (001) diamond surface on the electronic energy levels of an NV- centre buried beneath the surface. We find that, like OH termination, fluorine passivates the surface and reduces the influence of the surface on the electronic properties of the NV- centre. The results have significance for the optical properties of NV- defects in nanodiamonds.

It has been an accepted fact for more than 40 years that the E center in Si (the group-V impurity--vacancy pair)--one of the most studied defects in semiconductors--has only one energy level in the band gap: namely, the acceptor level at about 0.45 eV below the conduction band. We now demonstrate that it has a second level, situated in the lower half of the band gap at 0.27 eV above the valence band. The existence of this level, having a donor character, is disclosed by a combination of different transient-capacitance techniques and electronic-structure calculations. The finding seriously questions some diffusion-modeling approaches performed in the past.

The formation mechanism and properties of the boron-oxygen center responsible for the degradation of Czochralski-grown Si(B) solar cells during operation is investigated using density functional calculations. We find that boron traps an oxygen dimer to form a bistable defect with a donor level in the upper half of the band gap. The activation energy for its dissociation is found to be 1.2 eV. The formation of the defect from mobile oxygen dimers, which are shown to migrate by a Bourgoin mechanism under minority carrier injection, has a calculated activation energy of 0.3 eV. These energies and the dependence of the generation rate of the recombination center on boron concentration are in good agreement with observations.

Objective: To quantify inorganic pyrophosphate (PPi) production from extracellular adenosine triphosphate (ATP) by human serum or plasma., Methods: Serial measurements of ATP hydrolysis (t1/2) were performed by the luciferase method from a starting concentration of 1 microM in serum or platelet-poor plasma incubated under physiologic conditions. ATP was then pumped into another sample of each specimen using the rate constant derived from the ATP t1/2 of that specimen. Trace (32P) gamma ATP was added at the start of the infusion; conversion to (32P) inorganic orthophosphate (Pi) and to (32P) PPi was determined by precipitation of Pi as reduced phosphomolybdate before and after treatment with yeast pyrophosphatase., Results: ATP was hydrolyzed by all serum and plasma specimens; the rate of hydrolysis in serum and plasma from the same blood sample was nearly identical. PPi was the major product, averaging 71%., Conclusion: PPi is the major product of ATP catabolism in serum and platelet-poor plasma.

Left ventricular hypertrophy (LVH) is frequently present in patients referred for radionuclide ventriculography (RVG) for evaluation of left ventricular function. During interpretation of these studies, the nuclear medicine physician may have the subjective impression that increased septal thickening is present because of the abnormally prominent separation of the right and left ventricular blood pools. To examine the diagnostic reliability of this finding, we retrospectively reviewed the RVG studies of 43 consecutive patients and correlated the finding of subjectively increased septal thickness with established echocardiographic (ECHO) criteria and commonly used electrocardiographic (ECG) indices of LVH. Using standard ECHO measurements of septal thickness as a gold standard, RVG interpretation of septal thickening demonstrated a sensitivity of 0.69, specificity of 0.70, and accuracy of 0.70. When compared with standard ECG criteria for LVH, RVG performed quite favorably in the diagnosis of LVH confirmed by ECHO left ventricular mass index. We conclude that scintigraphic evidence of LVH should be reported when RVG studies are interpreted.

A technique for simultaneously measuring pulsation, translation and diffusion of a radioactive tracer in the spinal cerebrospinal fluid (CSF) has been described. To evaluate the accuracy and precision of this method for measuring CSF oscillation in the spine, an apparatus was designed that moved a radioactive source sinusoidally with known amplitude along a line. With list mode acquisition of radioactive emissions, the amplitude of oscillation was measured for a series of peak-to-peak amplitudes ranging from 0.01 mm to 3.8 mm. For oscillations larger than 0.35 mm peak-to-peak, measured values were within 6.1 percent of the expected values. For the spinal CSF, oscillation larger than 0.4 mm should be measured accurately with this technique.

Antibodies specific for polyriboadenylic acid (poly rA) are present in sera from patients with systemic lupus erythematosus and from NZB/NZW F1 mice. The specificity of these antibodies was established by inhibition of [3H]poly rA binding and by affinity chromatography. Poly rA binding was associated with the 19S and 7S regions when serum was fractionated by sucrose density gradient untracentrifugation. Young NZB/NZW F1 mice (1-5 months) had only 19S anti-poly rA, whereas old NZB/NZW F1 mice (2 years) had activity in both 19S and 7S regions, suggesting a possible age-dependent switching mechanism in the spontaneous development of antibodies to nucleic acids. The gamma-globulin fraction from an SLE patient was subjected to affinity chromatography on a column of poly rA covalently linked to Sepharose. An enriched population of IgG antibodies binding only poly rA, but not native or denatured DNA, was isolated in this manner. This procedure may have broad biological applicability for the preparation of isolated immunospecific anti-nucleic acid antibodies.

Although [99mTc] diethylenetriaminepentaacetic acid (DTPA) is currently the most widely used radioaerosol, rapid alveolar clearance limits its usefulness for single photon emission computed tomography (SPECT) ventilation lung imaging. Previous research has shown that [99mTc]phosphate compounds have high alveolar deposition and slow clearance and thus provide suitable aerosols for pulmonary ventilation studies. We have compared the pulmonary retention and blood levels of [99mTc]pyrophosphate (PYP) and [99mTc]DTPA in eight normal nonsmoking male volunteers. These two radioaerosols have comparable pulmonary deposition. Technetium-99m PYP, however, has a much slower pulmonary clearance which allows sufficient time (20 or more minutes) for SPECT data acquisition using a single-headed rotating gamma camera. While the radiation absorbed dose to the lungs for [99mTc]PYP (0.31 rad/mCi) is greater than for [99mTc]DTPA (0.11 rad/mCi), it is at a clinically acceptable and safe level.

The one-way mixed lymphocyte reaction was employed to study proliferative responses to antigens by mature, immunocompetent T cells from NZB mice 3 weeks to 4 months old. Compared to cells from control mice of the same H-2 type, thymus, spleen and lymph node cells from NZB mice were hyperactive in this response. The results are discussed in relation to possible effects of chronic stimulation by endogenous type C leukaemia virus upon differentiation of functional T cells or upon regulation by T cells of other T-cell functions, including augmentation of antibody responses.

To enable a more quantitative diagnosis of senile dementia of the Alzheimer type (SDAT), the authors developed and tested a semiautomated method to define regions of interest (ROIs) to be used in quantitating results from single photon emission computed tomography (SPECT) of regional cerebral blood flow performed with N-isopropyl iodine-123-iodoamphetamine. SPECT/IMP imaging was performed in ten patients with probable SDAT and seven healthy subjects. Multiple ROIs were manually and semiautomatically generated, and uptake was quantitated for each ROI. Mean cortical activity was estimated as the average of the mean activity in 24 semiautomatically generated ROIs; mean cerebellar activity was determined from the mean activity in separate ROIs. A ratio of parietal to cerebellar activity less than 0.60 and a ratio of parietal to mean cortical activity less than 0.90 allowed correct categorization of nine of ten and eight of ten patients, respectively, with SDAT and all control subjects. The degree of diminished mental status observed in patients with SDAT correlated with both global and regional changes in IMP uptake.

The knee of a boy with sickle-cell thalassemia became infected with Salmonella enteritidis, sensitive to ampicillin. Doses of ampicillin that achieved anti-bacterial titers of 32 in synovial fluid failed to eradicate the organism. The synovial fluid exhibited severe hypoxia, hypercapnia, and lactic acidosis. Methods were developed to estimate the oxygen saturation of blood in regional venous capillaries, the degree of periarticular sickling, changes in the viscosity of local blood, and the articular ratio of blood flow to oxygen utilization. The results suggest that local vascular insufficiency associated with sickling may affect host response to infection and efficacy of antibiotics. The Salmonella C1 readily transformed to an L form on hypertonic medium, thus acquiring resistance to ampicillin and other cell-wall inhibitors.

The clearance rate of isotopically labeled synthetic triclinic calcium pyrophosphate dihydrate (CPPD) crystals injection into rabbit joints was estimated by serial counting. Kinetic analysis using a four compartment model showed that half of the injected dose was cleared from 4 rabbit knee joints in 19.1 +/- 0.42 (SEM) days. Profound hypomagnesemia, produced in 2 rabbits with a low magnesium diet, did not affect the rate of crystal clearance detectably. Lavage of joints with solutions known to promote CPPD crystal solubility failed to remove detectable radioactivity. The previous finding of CPPD crystals in synovial phagocytes by electron microscopy, together with the finding of nuclide activity in the synovium and the failure to remove such activity by joint lavage, suggests that endocytosis by synovial cells is an important, effective mechanism controlling the synovial fluid concentration of crystals in patients with CPPD crystal deposition disease.

Two patients with sickle cell disorders developed gram-negative septic arthritis and responded poorly to conventional managment. Unfavorable factors included (1) confusion with the nonseptic arthropathy of a sickle crisis; (2) impaired articular perfusion, perhaps related to local sickling; (3) conversion of an infecting organism to an L-form in the presence of cell-wall inhibitors; and (4) interference with cultures and antibacterial titrations of synovial fluid caused by intro-articular administration of antibiotics. Prolonged treatment with very high doses of antibiotics was required to eradicate infection in both patients. Because sickling and local hypoxia apparently interfere with defenses against infection, anemia should be corrected by transfusion. One patient had had Reiter's syndrome; the dysenteric form of this disease may be a cause of arthritis in some sicklemic patients.

The diagnostic accuracy of both planar and single-photon emission computed tomography (SPECT) bone scintigraphy, radionuclide angiography, arthrography, and conventional radiography was evaluated in 36 patients with temporomandibular joint (TMJ) dysfunction undergoing preoperative testing. The sensitivity of SPECT bone scintigraphy (0.94) was comparable with arthrography (0.96) and significantly better than planar bone scintigraphy (0.76), radionuclide angiography (0.35), and transcranial lateral radiographs (0.04). While data for a larger asymptomatic control population are needed, preliminary results give SPECT a diagnostic specificity of 0.70 for internal derangements of the TMJ requiring surgical correction. It is concluded that SPECT bone scintigraphy is a useful noninvasive imaging test to screen for internal derangement of the TMJ.

The proliferative response of NZB and DBA/2 thymocytes and spleen cells to allogeneic cells and mitogens was studied in intact and lethally irradiated bone marrow-repopulated syngeneic recipients. The major findings were complete recovery of function in NZB spleen cells and premature recovery in thymocytes compared to the control DBA/2 strain. This recovery was not influenced by the administration of thymosin to the recipients, and was not due to functional thymocytes present in the donor marrow inoculum. These results suggest normal or increased support of T cell differentiation by the radioresistant thymus in 4-month-old NZB mice. Thymic epithelial cell products regulating T cell maturation may be disordered or unbalanced but do not appear to be broadly deficient at this age.

The authors devised a new technique for measuring cerebrospinal fluid movement in the spine. With gated list mode acquisition of radioactive emissions, bulk flow, oscillations, and dispersion of a bolus of isotope can be measured. The accuracy of the technique was measured in a simulation in which fluid oscillated at 71 cycles/minute and displaced at 6.5 cm/minute. With this method, the measured oscillation frequency and amplitude and the rate of translation were within 10% of actual values.

Iodine-123 (123I) produced by the 124Te(p,2n)123I reaction contains several percent 124I radionuclidic contamination at the time of imaging. Since 124I degrades the quality of the images and causes unnecessary radiation absorbed dose to the patient, it is important to know the amount present in radiopharmaceuticals at the time of administration. A simple approach is described which uses a radionuclide dose calibrator and lead shield. The sample is assayed both shielded and unshielded and the ratio of readings depends uniquely upon the percent 124I present. The technique can be adopted for any type of dose calibrator, sample container, and Pb shield, but use of the numeric constants reported here should be restricted to the specified equipment.

A thyroid fluorescent scanner has proven to be useful for imaging thyroids in cases where isotope scans are contraindicated. Minor modifications of a commercially available scanner make possible total intrathyroidal quantification, which aids in the differentiation between primary and secondary hypothyroidism and in the diagnosis of thyroiditis.

We studied clearance of acid from the esophagus and esophageal emptying in normal subjects. A 15-ml bolus of 0.1 N hydrochloric acid (pH 1.2) radiolabeled with [99mTc]sulfur colloid was injected into the esophagus, and the subject swallowed every 30 seconds. Concurrent manometry and radionuclide imaging showed nearly complete emptying of acid from the esophagus by an immediate secondary peristaltic sequence, although esophageal pH did not rise until the first swallow 30 seconds later. Esophageal pH then returned to normal by a series of step increases, each associated with a swallow-induced peristaltic sequence. Saliva stimulation by an oral lozenge shortened the time required for acid clearance, whereas aspiration of saliva from the mouth abolished acid clearance. Saliva stimulation or aspiration did not affect the virtually complete emptying of acid volume by the initial peristaltic sequence. We conclude that esophageal acid clearance normally occurs as a two-step process: (1) Virtually all acid volume is emptied from the esophagus by one or two peristaltic sequences, leaving a minimal residual amount that sustains a low pH, and (2) residual acid is neutralized by swallowed saliva.

Twenty patients with Stage I or II breast cancer, all of whom had undergone radiation therapy planning, were examined with internal mammary lymphoscintigraphy (IMLS) and computed tomography (CT). Based on the results of IMLS, radiation fields were revised in 12 cases (60%). The mean number of nodes identified by IMLS in each patient was 7.8, which is in agreement with previously published autopsy and scintigraphic data. CT identified 243 possible nodes of normal size, but only 49 of them were within 10 mm of regions shown to be positive on the scintigram. The authors conclude that IMLS is the method of choice for defining parasternal lymphatic drainage and identifying those internal mammary nodes that are normal in both size and function.

Regional CBF (rCBF) images obtained from xenon-enhanced computed tomography (XeCT) and single-photon emission computed tomography (SPECT) with N-isopropyl-p-[123I]iodoamphetamine (IMP) done with a rotating gamma-camera were compared in nine patients. Both XeCT and SPECT/IMP demonstrated flow abnormalities at all sites of infarction identified by CT, while detecting reduced rCBF in areas normal by CT in eight of the nine patients. All areas that were abnormal on XeCT were abnormal on the comparable SPECT/IMP images. The major advantages of XeCT are its greater resolution and potential for noninvasive quantitation of rCBF, while the major advantage of SPECT/IMP is its visualization of the entire brain on transverse, coronal, and sagittal sections.

Splenic lymphocytes from both normal and autoimmune mice bind significant quantities of polyriboadenylic acid (poly rA) when incubated with radiolabeled poly rA for 40 min at 37 degrees C. This poly rA binding is specifically inhibited by an excess of nonradioactive poly rA and by anti-mouse immunoglobulin. Poly rA binding is decreased by exposing spleen cells to Pronase and is restored by subsequent culture for 18 to 72 hr. Poly rA-binding activity is associated more with bone marrow-derived than with thymus-derived lymphocytes. These results suggest the presence of autoantigen-binding lymphocytes in normal as well as autoimmune mice. Furthermore, spleen cells from normal and autoimmune mice cultured for 72 hr synthesize and secrete antibodies to poly rA and DNA. These antibodies can be recovered from the culture supernatants by a solid immunoadsorbent technique and antibody immunoprecipitation. The synthesis of antibodies to nucleic acids by normal spleen cells suggests that autoreactive lymphocytes may be released from normal immunoregulatory control during in vitro culture conditions.

We evaluated whether chronic nausea and vomiting in diabetic patients correlate with abnormal gastric emptying of liquid or solid, or both liquid and solid, radiolabeled meals and recorded the acute effects of metoclopramide. last, we compared several methods of analyzing gastric emptying data obtained using the gamma-camera. Eighteen healthy control subjects and 16 insulin-dependent diabetics with neuropathy were investigated. Ten of the patients suffered from chronic nausea and vomiting; the remaining 6 served as disease controls. Gastric emptying of solid and liquid meals could best be described by the slopes of two linear components and their intercept. Liquid meals generally were handled normally, while solid meals were emptied slowly by both groups of diabetics. A single dose of metoclopramide frequently corrected the delayed onset of the second, more rapidly emptying phase, that is, the major abnormality of solid emptying. The radiologic findings during a barium meal did not distinguish symptomatic from asymptomatic patients. We conclude that abnormal gastric motor function, manifested by delayed emptying of a solid meal or barium suspension, or both, is common in diabetics with neuropathy and that this motor abnormality is not the only cause of chronic vomiting. The beneficial, often short-term symptomatic effects of metoclopramide in these patients appear to be mediated by a combination of normalization of gastric emptying and a central antiemetic action.

By raising the lower threshold of the Tc-99m energy window, rejection of scattered photons can be made more efficient. Unfortunately, with most gamma cameras significant nonuniformities are produced when the window is changed to an asymmetric setting. Recently introduced designs with gain stabilization of the photomultiplier tubes and improved energy correction maintain field uniformity even for an asymmetric window. To assess the impact of an asymmetric energy window on clinical images, 33 Tc-99m-MDP scintigrams of the lumbar spine were taken with symmetrical (126-154 keV) and asymmetric windows (135-154 keV). Bone:soft tissue ratios improved with the asymmetric window, and the resulting images were preferred by the physicians questioned.

Synthetic triclinic calcium pyrophosphate dihydrate crystals were uniformly trace-labeled with Ytterbium-169 (169Yb), a pure gamma-emitting isotope with a halflife of 31 days. The solubility of the labeled crystals was similar to that of cold synthetic crystals. The clearance rate of labeled sterile crystals, sieved to obtain the desired size, was determined after injection of microgram quantities into 4 arthritic huuman and 3 normal adult rabbit joints and corrected by the observed rate of clearance of free 169Yb. The derived rate constants were then used to calculate the time required for half of the injected dose of CPPD to be cleared from the joint. Crystal clearance was found in all instances. Crystal removal from normal rabbit joints was much more rapid than from the much larger human arthritic joints and was inversely proportional to the size of the crystals injected.

A spontaneous lymphoma (141) producing monoclonal IgM is established in NZB/NZW F(1) (B/W) mice who spontaneously develop an autoimmune disease. Idiotypic determinants of 141 IgM are present on the lymphoma cell surface as shown by indirect immunofluorescence and specific cytotoxicity with rabbit anti-idiotypic antiserum. Fluorescence and cytotoxicity are inhibited by 141 IgM but not by 104E IgM, a monoclonal IgM produced by a BALB/c plasmacytoma. Immunization of B/W mice with 141 IgM before transplantation of lymphoma 141 confers protective immunity. No such protection occurs after immunization with 104E IgM or other unrelated proteins. Protected mice contain spleen cells cytotoxic for 141 lymphoma cells. This cytotoxicity is blocked by incubation of spleen cells with 141 IgM but not with 104E IgM. Moreover, splenic lymphocytes from protected mice are stimulated to synthesize DNA by 141 IgM but not by 104E IgM. These results suggest that specific cellular immune responses to idiotypic determinants may participate in the observed protection against challenge with the corresponding B-cell tumor.