Imaging and quantitation of dopamine transporters with iodine-123-IPT in normal and Parkinson's disease subjects

Iodine-123-N-(3-iodopropene-2-yl)-2beta-carbomethoxy-3beta-( 4-chlorophenyl) tropane (123I-IPT) is a new dopamine transporter ligand that selectively binds the dopamine reuptake sites. Transporter concentrations have been known to decrease in Parkinson's disease patients. The purpose of this study was to evaluate the usefulness of IPT as an imaging agent for measuring changes in transporter concentrations in Parkinson's disease. METHODS: IPT labeled with 6.78 +/- 0.67 mCi 123I was injected intravenously as a bolus into eight normal controls (mean age 41 +/- 12 yr) and 17 Parkinson's disease patients (mean age 55 +/- 9 yr). Dynamic SPECT scans of the brain were then performed for 5 min each over 120 min on a triple-headed gamma camera equipped with medium-energy collimators. Regions of interest were drawn on the middle set of the image at the level of the basal ganglia (BG) for each subject. Time-activity curves were generated for the left BG, right BG and occipital cortex (OCC). The empirical ratios between BG-OCC and OCC, which represent specific-to-nonspecific binding ratios, were computed at various time points. The statistical parameter k3/k4 was estimated by two methods: a variation of the graphic method that derives the ratio of ligand distribution volumes (R[V]) and the area ratio method (R[A]), in which the ratio is calculated from the areas under the specific and nonspecific binding activity curves. RESULTS: The mean (BG-OCC)/OCC ratio for normal controls (3.07 +/- 0.73) was significantly higher than that for Parkinson's disease patients at 115 min (1.10 +/- 0.56) (p = 2.76 x 10[-5]). The mean R(V) and R(A) for normal controls were 2.06 +/- 0.27 and 1.50 +/- 0.15, respectively. The mean R(V) and R(A) for Parkinson's disease patients were 0.78 +/- 0.31 and 0.65 +/- 0.24, respectively. Both R(V) and R(A) for normal controls were significantly higher than those for Parkinson's disease patients (p values for R(V) and R(A) were 1.91 x 10(-8) and 3.46 x 10(-10), respectively). The R(V) has linear relationships with both R(A) and (BG-OCC)/OCC ratio at 115 min. The R(V) has a higher correlation (r = 0.99) with R(A) than it does with (BG-OCC)/OCC (r = 0.93). CONCLUSION: The R(V), R(A) and (BG-OCC)/OCC for Parkinson's disease patients were clearly separated from those of normal controls, and they may be useful outcome measures for clinical diagnosis. The simplest (BG-OCC)/OCC ratio, requiring a single late time point, could be useful in clinical situations, whereas R(V) or R(A) is preferred when the dynamic data are available. The findings suggest that 123I-IPT is a useful tracer for diagnosing Parkinson's disease and studying dopamine reuptake sites.     

Effects of decarburization and normalizing heat treatment in boron-silicon iron alloys

Effects of carbon content and various heat treatments on the secondary recrystallization in boronsilicon iron have been studied by measurement of induction at a magnetizing force of 800 A/m and examination of microstructures at various stages of sample preparation process. Carbon was varied before and after hot rolling by adding carbon to the melts and by oxide decarburization of hot bands at 700 °C. Results show that complete secondary recrystallization and high induction (1.92 Tesla) are obtained from heats whose hot bands have been decarburized at 700 °C to a level of 30 to 40 ppm provided the heats contained 0.039 to 0.049 wt Pct carbon during heating for hot rolling. From these facts and analysis of microstructures of cross-sectional area of specimens at various stages of process it can be said that one of the major roles that carbon plays is to introduce, through transformation of austenite, a nonuniform layer-like microstructure during hot rolling and during the normalizing heat treatment of the hot band. This structure continues to exist in the final cold rolled sheet and results in anisotropic growth of secondary grains, and plays a significant role in the secondary recrystallization of boron-silicon iron. This paper is based on a presentation made at the symposium “Physical Metallurgy of Electrical Steels” held at the 1985 annual AIME meeting in New York on February 24–28, 1985, under the auspices of the TMS Ferrous Metallurgy Committee.     

Shear yielding modes of polycarbonate

The modes of shear yielding in edge-notched sheets of polycarbonate have been studied under slow tensile loading. Optical microscope techniques were used to characterize the flow lines through the thickness of the plastically deformed region. Three modes are observed, namely core yielding, hinge shear and intersecting shear. Core yielding consists of two families of shear flow lines contained in the centre region where the stress is highest. In the nearly plane strain condition, the dominating shear mode is hinge shear which is through-thickness yielding on inclined planes above and below the notch. Intersecting shear dominates in the nearly plane stress condition. In this case, yielding occurs through the entire thickness by slip along planes parallel to the width direction that make an angle with the plane of the sheet. It produces a necking effect in front of the notch. The thickness dependent transition from hinge shear to intersecting shear follows conditions suggested by Hahn and Rosenfield.     

The effect of melt-flow properties of PVC plastisols during fusion cycle on flooring wear layer surface quality

A rheological test to characterize the melt in various vinyl coating resins in a flooring wear layer formulation shows that the surface quality (absence of orange-peel) of the resilient foamed flooring is associated with the viscoelastic nature of the wear layer resin during the cure cycle: Resins with high molecular weight of a sufficiently high melt viscosity showed no entrapment of air bubbles or tendency to orange-peel, while resins with low melt viscosity produced very severe orange-peel. Orange-peel is independent of the type of foam resin used. For a given formulation, the proper selection of wear layer resin or resin mixtures that will develop the desired hot melt strength to contain the gases given off by the decomposition of the blowing agent, will help to alleviate or minimize orange-peel.     

Tuberculous abscess in retromammary region: CT findings

PURPOSE: Our goal was to evaluate CT findings of tuberculous abscess in the retromammary region of the breast. METHOD: Four patients with tuberculosis extending from the retromammary region to the pleura were examined by CT and the findings were evaluated. All cases were also examined with mammography and two cases were evaluated with sonography. Diagnosis was confirmed by acid-fast bacillus stain, culture, and histologic examination. RESULTS: Mammography showed relatively smoothly marginated, round mass density in two cases, nodular density in one, and focal bulging of the pectoral wall in one. A sonogram demonstrated in two cases a fistulous connection from the heterogeneous, fluid-containing lesion with floating internal debris in the retromammary region to the thoracic cavity. In all four cases, CT showed relatively smoothly marginated, inhomogeneous, hypodense lesions with surrounding rims of the cold abscess type. A direct fistulous connection from the retromammary lesion through the thoracic wall into the pleura was seen in two cases. Destroyed rib fragments within the abscess were noted in two cases. CONCLUSION: A tuberculous abscess in the retromammary region usually showed on CT a focal, smoothly marginated, inhomogeneous, hypodense lesion with a surrounding enhancing rim. A direct fistulous connection with the pleura or a destroyed rib fragment in the abscess as revealed by CT can be helpful in the differential diagnosis of other infectious types of retromammary abscess.     

Observation of a fast-formed absorption grating and a slowly formed phase grating in undeveloped dichromated gelatin

Real-time diffraction efficiency is measured during hologram formation in undeveloped dichromated gelatin (DCG) film. The main features of real-time diffraction efficiency of undeveloped DCG reveal double peaks with increasing exposure time. Adopting the grating translation technique, we show that the first peak originates from the absorption grating and that the latter is related to the phase grating. To explain such complicated hologram-formation dynamics, we present a phenomenological model for mixed gratings associated with photoinduced refractive-index changes and absorption changes. We have compared the model results with the experimental results, which show good agreement.