Ultra-low dose chest CT for the diagnosis of pulmonary arteriovenous malformation in patients with hereditary hemorrhagic telangiectasia

PURPOSE

The purpose of this study was to compare ultra-low dose (ULD) and standard low-dose (SLD) chest computed tomography (CT) in terms of radiation exposure, image quality and diagnostic value for diagnosing pulmonary arteriovenous malformation (AVM) in patients with hereditary hemorrhagic telangiectasia (HHT).

MATERIALS AND METHODS

In this prospective board-approved study consecutive patients with HHT referred to a reference center for screening and/or follow-up chest CT examination were prospectively included from December 2020 to January 2022. Patients underwent two consecutive non-contrast chest CTs without dose modulation (i.e., one ULD protocol [80 kVp or 100 kVp, CTDIvol of 0.3 mGy or 0.6 mGy] and one SLD protocol [140 kVp, CTDIvol of 1.3 mGy]). Objective image noises measured at the level of tracheal carina were compared between the two protocols. Overall image quality and diagnostic confidence were scored on a 4-point Likert scale (1 = insufficient to 4 = excellent). Sensitivity, specificity, positive predictive value and negative predictive value of ULD CT for diagnosing pulmonary AVM with a feeding artery of over 2 mm in diameter were calculated along with their 95% confidence intervals (CI) using SLD images as the standard of reference.

RESULTS

A total of 44 consecutive patients with HHT (31 women; mean age, 42 ± 16 [standard deviation (SD)] years; body mass index, 23.2 ± 4.5 [SD] kg/m2) were included. Thirty-four pulmonary AVMs with a feeding artery of over 2 mm in diameter were found with SLD images versus 35 with ULD images. Sensitivity, specificity, predictive positive value, and predictive negative value of ULD CT for the diagnosis of PAVM were 100% (34/34; 95% CI: 90-100), 96% (18/19; 95% CI: 74-100), 97% (34/35; 95% CI: 85-100) and 100% (18/18; 95% CI: 81-100), respectively. A significant difference in diagnostic confidence scores was found between ULD (3.8 ± 0.4 [SD]) and SLD (3.9 ± 0.1 [SD]) CT images (P = 0.03). No differences in overall image quality scores were found between ULD CT examinations (3.9 ± 0.2 [SD]) and SLD (4 ± 0 [SD]) CT examinations (P = 0.77). Effective radiation dose decreased significantly by 78.8% with ULD protocol, with no significant differences in noise values between ULD CT images (16.7 ± 5.0 [SD] HU) and SLD images (17.7 ± 6.6 [SD] HU) (P = 0.07).

CONCLUSION

ULD chest CT provides 100% sensitivity and 96% specificity for the diagnosis of treatable pulmonary AVM with a feeding artery of over 2 mm in diameter, leading to a 78.8% dose-saving compared with a standard low-dose protocol.

Ozone spectroscopy in the terahertz range from first high-resolution Synchrotron SOLEIL experiments combined with far-infrared measurements and ab initio intensity calculations

Ozone is one of the important molecules in terms of the impact on the atmospheric chemistry, climate changes, bio- and eco-systems and human health. It has a strong absorption in the microwave, terahertz and far-infrared spectral ranges where a large part of the Earth's outgoing longwave radiation to space is located. In this work, the observations, and analyses of the ozone high-resolution spectra in the THz range recorded using the Synchrotron light source of the SOLEIL CNRS equipment are reported for the first time. Thanks to the exceptional brightness of the Synchrotron radiation and to the signal/noise ratio, it was possible to observe many more ozone transitions of the cold rotational band and the hot ν2-ν2 band in the range 0.9-6 THz compared to the previous works. In addition, we have carried out new measurements and assignments for the ν2 band. The simultaneous fit of the rotational band GS-GS, the hot band ν2-ν2 and the FIR ν2 band yielded an overall weighted standard deviation of 0.68 for 13,466 line positions within the experimental accuracy. This includes all previously available MW (with the best uncertainty 0.1 - 10 kHz), FIR data and the original SOLEIL measurements that provided experimental accuracy of 0.00005 - 0.0001 cm-1 for the best lines. Significant deviations in new experimental spectra compared to available spectroscopic databases were evidenced, particularly for the line positions and energy levels at high J, Ka rotational quantum numbers that are the most pronounced in the 4.5 - 6 THz range. Accurate ab initio calculations of line intensities combined with empirically fitted line positions were used to create new linelists that permit theoretical modelling of the transmittance in a good agreement with the Synchrotron spectra in the entire range of observations for various pressures and optical paths. The region near 100 cm-1 and above appears to be more sensitive to the temperature conditions that should be considered in atmospheric observation for the currently operational and future ground based and space missions.

Simultaneous Nitrite/Nitrate Imagery at Millimeter Scale through the Water-Sediment Interface

The present study describes new procedures to obtain at millimeter resolution the spatial distribution of nitrite and nitrate in porewaters, combining diffusive equilibrium in thin films (DET), colorimetry and hyperspectral imagery. Nitrite distribution can be easily achieved by adapting the well-known colorimetric method from Griess (1879) and using a common flatbed scanner with a limit of detection about 1.7 μmol L(-1). Nitrate distribution can be obtained after reduction into nitrite by a vanadium chloride reagent. However, the concentration of vanadium chloride used in this protocol brings coloration with a wide spectral signature that creates interference only deconvolvable by imaging treatment from an entire visible spectrum for each pixel (spectral analysis). This can be achieved by hyperspectral imaging. The protocol retained in the present study allows obtaining a nitrite/nitrate image with micromolar limit of detection. The methods were applied in sediments from the Loire Estuary after different treatments and allowed to precisely describe two-dimensional millimeter features. The present technique adds to the combination of gel-colorimetry and hyperspectral imagery a very promising new application of wide interest for environmental issues in the context of early diagenesis and benthic fluxes.

Does the "reef structure" at the ozone transition state towards the dissociation exist? New insight from calculations and ultrasensitive spectroscopy experiments

Since the discovery of anomalies in ozone isotope enrichment, several fundamental issues in the dynamics linked to the shape of the potential energy surface in the transition state region have been raised. The role of the reeflike structure on the minimum energy path is an intricate question previously discussed in the context of chemical experiments. In this Letter, we bring strong arguments in favor of the absence of a submerged barrier from ultrasensitive laser spectroscopy experiments combined with accurate predictions of highly excited vibrations up to nearly 95% of the dissociation threshold.

Analysis of High-Resolution Spectra of (18)O(3)

The analysis of high-resolution spectra of (18)O(3) is reported here for the range 3100-5000 cm(-1). Eight sets of polyads, corresponding to eight newly observed bands and accounting for resonance perturbations with eight other "dark" states, are analyzed for the first time. These analyses lead to eight sets of spectroscopic parameters, band centers, and rotational and centrifugal distortion constants, as well as transition moment parameters. In addition, various resonances are studied and compared to the similar ones for (16)O(3). This study allows us to check the work on (16)O(3) and to confirm that the accidentally strong high-order Deltav=8 anharmonic resonance for bands 5 nu(3)<-->3nu(1)+nu(2)+nu(3) was an exceptional case of the major isotopic species. Copyright 2001 Academic Press.

Analysis of High-Resolution Spectra of (18)O(3)

Using a Fourier transform spectrometer, we have recorded the spectra of the (18)O(3) species of ozone in the region 1300-3100 cm(-1), with a resolution of 0.003 cm(-1). The large product pathlength x pressure enable us to record 18 bands, 14 for the first time. The analysis has been performed using effective Hamiltonians for polyads of strongly interacting states for ozone, accounting for Coriolis and anharmonic resonances. The spectral parameters are derived for 16 vibrational states, including the two "dark" states (040) and (130). Various resonances are studied through the mixing coefficients of rovibrational wavefunctions. Systematic intensity measurements allow determination of transition moment parameters for 16 bands. Finally, a complete list of all transitions from 1300 to 3100 cm(-1), with cutoffs 10(-26) cm(-1)/mol cm(-2) (296 K), is calculated. Copyright 2001 Academic Press.

Absolute Intensities of the 10-µm Bands of (16)O(3)

Two hundred ninety experimental absolute intensities of nu(1) and nu(3) transitions of ozone have been measured, with good accuracy (<2%). They are used to derive the transition-moment parameters for these bands. The agreement between our observed and calculated line intensities is satisfactory. This work shows that the intensities of these two bands are on average 4% smaller than those used in the literature. In addition, 20 intensities of the nu(2) + nu(3) - nu(2) band confirm this value. Also, 42 line intensities of the 2nu(1)-nu(3) band are reported. Copyright 2001 Academic Press.

Determination of the Effective Ground State Potential Energy Function of Ozone from High-Resolution Infrared Spectra

The effective ground state potential energy function of the ozone molecule near the C(2v) equilibrium configuration was obtained in a least-squares fit to the largest sample of experimental, high-resolution vibration-rotation data used for this purpose so far. The fitting is based on variational calculations carried out with the extended Morse Oscillator Rigid Bender Internal Dynamics model. The potential function is expanded in Morse-type functions of the stretching variables and in cosine of the bending angle. The present calculation produces results in significantly better agreement with experiment than previous determinations of the potential energy surface, and the energies predicted with the new surface are sufficiently accurate to be useful for the assignment of new high-resolution spectra. The rms (root-mean-square) deviation of the fit of rovibrational data up to J = 5 is 0.02 cm(-1). For the set of all 60 band centers of the (16)O(3) molecule included in the Atlas of Ozone Line Parameters, the rms deviation is 0.025 cm(-1), and for all band centers determined so far from high-resolution spectra, including those recently observed and assigned in Reims corresponding to highly excited stretching and bending vibrations (v(1) + v(2) + v(3) = 6), the rms deviation is 0.1 cm(-1). The "dark states" that produce resonance perturbations in the observed bands are described with experimental accuracy up to the (v(1)v(2)v(3)) = (080) state. Extrapolation tests demonstrate the predictive power of the potential function obtained: rotational extrapolation up to J = 10 for the 11 lowest vibrational states results in an rms deviation of 0.06cm(-1). Also, vibrational energies measured by low-resolution Raman spectroscopy (which were not included in the input data for the fit) are calculated within the experimental accuracy (rms = 1.6 cm(-1)) of the experimental values up to the dissociation limit. The statistical analysis suggests that the accuracy of the equilibrium geometry and force constants of the molecule is considerably improved relative to previous determinations. The long-range behavior of the fitted potential at the dissociation limit O(3) --> O(2) + O shows very good agreement with experimental data. The new potential energy surface was used to predict the band centers of the isotopomers (17)O(3) and (18)O(3). Copyright 1999 Academic Press.

New Analysis of 2nu1 + nu2, nu1 + nu2 + nu3, and nu2 + 2nu3 Bands of Ozone in the 2600-2900 cm-1 Region

The 2600-2900 cm-1 spectral range is revisited for an accurate determination of line intensities of the 2nu1 + nu2, nu1 + nu2 + nu3, and nu2 + 2nu3 bands of ozone. The fit on 1702 energy levels of (012), (111), and (210) states determined from observed transitions with Jmax </= 61 and Ka max </= 17 gives a rms = 5.6 x 10(-4) cm-1 and provides a satisfactory agreement between calculated and observed line positions. Line intensities have been measured and fitted, leading to the determination of transition moment parameters for the three bands. Using these parameters, we have obtained the following estimations for the integrated band intensities S(nu1 + nu2 + nu3) = 2.509 x 10(-20), S(nu2 + 2nu3) = 0.330 x 10(-20), and S(2nu1 + nu2) = 0.0802 x 10(-20) cm-1/mol cm-2 at 296 K, with a cutoff of 10(-26) cm-1/mol cm-2. The value of the µ(210)-(000)1 parameter associated with the &phi;x operator for 2nu1 + nu2 band obtained in our analysis appears to be eight times smaller than the previously determined value of this parameter [M. A. H. Smith, C. P. Rinsland, J. M. Flaud, C. Camy-Peyret, and A. Barbe, J. Mol. Spectrosc. 139, 171-181 (1990)]. The general line listing of the 2nu1 + nu2, nu1 + nu2 + nu3, and nu2 + 2nu3 bands (up to Jmax = 70 and Ka max = 23) has been generated with an intensity cutoff 10(-26) cm-1/mol cm-2. The perturbations of (111) and (012) states by the (040) state are discussed. Copyright 1999 Academic Press.

The 2nu1 + nu2 + 3nu3 Band of 16O3: Line Positions and Intensities

The 2nu1 + nu2 + 3nu3 band of ozone, which occurs in the 5700-cm-1 region, has been observed for the first time using a Fourier Transform Spectrometer, operating at 0.008 cm-1 resolution and with a large pathlength x pressure product (3216 cm x 28.3 Torr). The assignment of rotation-vibration transitions has been done for J up to 38 and Ka up to 11, respectively, after many difficulties due to a Coriolis coupling between (213) and (420) states. In this work we show how this one, which occurs between closed band centers (4 cm-1) but corresponds to summation operatoriDelta vi = 6, strongly perturbs energy levels and leads to a difficulty in assignments. In particular we show the deviations for various types of J and Ka as large as 1 cm-1, with respect to the calculations performed without account of this resonance. The final calculation for the 212 rovibrational states is very satisfactory, as the r.m.s. is 2.5 x 10(-3) cm-1, near the experimental accuracy, with meaningful spectroscopic Hamiltonian parameters. Rovibrational lines intensities of the 2nu1 + nu2 + 3nu3 band were measured, and the value of the transition moment has been recovered. Finally a complete list of line positions and intensities was calculated (with a cut-off of 3 x 10(-26) cm-1/molecule cm-1) leading to a total band intensity of Sv = 3.118 10(-23) cm-1/molecule cm-2 at 296 K. Copyright 1998 Academic Press.

Lambda-Splittings and Line Intensities in the 3 <-- 1 Hot Band of 14N16O: The Spectrum of Nitric Oxide in the First Overtone Region

Intensities and Lambda-splittings have been measured for lines belonging to the 3 <-- 1 hot band of 14N16O. The vibrational transition moment and the Herman-Wallis coefficient have been determined. Hamiltonian constants have been calculated for the four vibrational states v = 0, 1, 2, and 3, and a synthetic spectrum has been generated in the first overtone region of NO, taking into account the hyperfine structure for the 2 <-- 0 band. Copyright 1998 Academic Press. Copyright 1998Academic Press

First Study of the v2 = 3 Dyad {(130), (031)} of Ozone through the Analysis of Hot Bands in the 2300-2600 cm-1 Region

Hot bands nu1 + 3nu2 - nu2 and 3nu2 + nu3 - nu2 of 16O3 in the region 2300-2600 cm-1 and the cold band 3nu2 + nu3 in the region 3050-3110 cm-1, corresponding to the v2 = 3 dyad {(130), (031)}, have been observed for the first time, using the Fourier Transform Spectrometer (FTS) at Reims and the usual experimental setup providing a large product pressure x path length, p x l. Three hundred sixty-five rovibration energy levels of the upper states were obtained with J and Ka up to 46 and 9, respectively. The fit of these data gives a r.m.s. deviation of 1.93 x 10(-3) cm-1. The v2 dependence of the rotational parameters A, B, and C for the (1v20) and (0v21) states is discussed. Copyright 1998 Academic Press. Copyright 1998Academic Press

Lambda-Splittings and Line Intensities in the First Overtone of Nitric Oxide

Using Fourier transform spectra, absolute line parameters (positions, Lambda splittings, and intensities) have been measured in the two allowed subbands 2Pi1/2-2Pi1/2 and 2Pi3/2-2Pi3/2 of the 2 <-- 0 vibrational band of the 14N16O molecule. These line parameters have been compared with previous experimental results and with the values available in the current HITRAN database. The measured line intensities led to the determination of the transition dipole moment as well as the Herman-Wallis coefficients. Improved spectroscopic constants were also obtained for the v = 2 vibrational state. Copyright 1997 Academic Press. Copyright 1997Academic Press

Infrared Spectrum of Ozone in the 4600 and 5300 cm-1 Regions: High Order Accidental Resonances through the Analysis of nu1 + 2nu2 + 3nu3 - nu2, nu1 + 2nu2 + 3nu3, and 4nu1 + nu3 Bands

The very weak bands nu1 + 2nu2 + 3nu3 and 4nu1 + nu3 of 16O3 have been observed for the first time, using the Fourier transform spectrometer (FTS) of Reims and the usual experimental setup providing a large product p x l of approximately 38 Torr x 36 m. The upper levels of these A-type bands which are rather close in energy (they appear respectively at 5291.722 and 5307.790 cm-1) belong to two different sets of interacting polyads. To correctly reproduce the rotation-vibration energy levels and account for the observed perturbations, both bands are treated in a dyad approximation: the (123) state in the Coriolis resonance with the (330) state, and the (401) state in the Coriolis resonance with the (024) state. The assignments of the rotation-vibration levels of the (123) state are confirmed by measurements of line positions of the hot band nu1 + 2nu2 + 3nu3 - nu2 which has also been observed for the first time. The fits are very satisfactory: the r.m.s. deviation for 249 energy levels of the (123) state is 2.4 x 10(-3) cm-1 and is 2.0 x 10(-3) cm-1 for 266 levels of the (401) state. These r.m.s. are near experimental accuracy. Transition moments for the three observed bands are determined from measured line intensities. Copyright 1997 Academic Press. Copyright 1997Academic Press

Analysis of the 2nu1 + nu2 + 2nu3 Band of Ozone

The 2nu1 + nu2 + 2nu3 band of ozone, occurring in the 4780 cm-1 region, has been observed for the first time, using a Fourier transform spectrometer, at 0.008 cm-1 resolution and using a large path length pressure product. Assignments of vibration-rotational transitions have been made up to J = 48 and Ka = 9. As a few levels with Ka = 1 or 2 are perturbed, it has been necessary to take into account the Coriolis resonance between the (212) and (141) vibrational states. With the effective Hamiltonian explicitly accounting for the interaction between these two states, the fit on 165 energy levels leads to the rms deviation of 1.9 x 10(-3) cm-1, which is near the experimental accuracy. Line intensities of the 2nu1 + nu2 + 2nu3 band have been measured and calculated. The set of spectroscopic parameters for interacting bands, as well as transition moment constants, is given. A complete list of line positions and intensities, with a cutoff of 1 x 10(-26) cm-1/molecule.cm-2 at 296 K up to J = 65 and Ka = 15, has been generated, which leads to the integrated band intensity Sv (2nu1 + nu2 + 2nu3) = (5.1 +/- 2.0) x 10(-23) cm-1/molecule.cm-2. Copyright 1997Academic Press

Electron microscopic serial analysis of GABA presynaptic terminals on the axon hillock and initial segment of labeled abducens motoneurons in the rat

The aim of the present study was to provide a quantitative analysis of the synapses made onto the axon hillock and initial segment of rat abducens motoneurons retrogradely or intracellularly stained with HRP. GABA-immunoreactive terminals contacting these axons were visualized using a postembedding procedure. The presynaptic terminals contained either spherical or pleomorphic vesicles. gamma-Aminobutyric acid (GABA)-immunoreactive axon terminals, which belonged to this last category, were distributed both onto axon hillocks and the proximal part of initial segments. The percentage of axonal membrane covered by synapses ranged from 44.1 to 68.2%. A quantitative analysis performed on a series of ultrathin sectioned terminals contacting the axon of an intracellularly labeled motoneuron revealed a significant correlation between the length of membrane apposition of the terminals and their perimeter or surface area, and also between the area of membrane apposition and terminal volume. GABA-immunoreactive terminals had a mean perimeter and volume that were larger than those of unlabeled axon terminals. The number of active zones was correlated with the area of apposition. Some hypotheses concerning the functional role of the GABAergic innervation of this particular part of the neuron are discussed.

Line Positions and Intensities of the nu1 + nu2 + 3nu3, nu2 + 4nu3, and 3nu1 + 2nu2 Bands of Ozone

Using a Fourier transform spectrometer, we have recorded the spectra of ozone in the region of 4600 cm-1, with a resolution of 0.008 cm-1. The strongest absorption in this region is due to the nu1 + nu2 + 3nu3 band which is in Coriolis interaction with the nu2 + 4nu3 band. We have been able to assign more than 1700 transitions for these two bands. To correctly reproduce the calculation of energy levels, it has been necessary to introduce the (320) state which strongly perturbs the (113) and (014) states through Coriolis- and Fermi-type resonances. Seventy transitions of the 3nu1 + 2nu2 band have also been observed. The final fit on 926 energy levels with Jmax = 50 and Kmax = 16 gives rms = 3.1 x 10(-3) cm-1 and provides a satisfactory agreement of calculated and observed upper levels for most of the transitions. The following values for band centers are derived: nu0(nu1 + nu2 + 3nu3) = 4658.950 cm-1, nu0(3nu1 + 2nu2) = 4643.821 cm-1, and nu0(nu2 + 4nu3) = 4632.888 cm-1. Line intensities have been measured and fitted, leading to the determination of transition moment parameters for the two bands nu1 + nu2 + 3nu3 and nu2 + 4nu3. Using these parameters we have obtained the following estimations for the integrated band intensities, SV(nu1 + nu2 + 3nu3) = 8.84 x 10(-22), SV(nu2 + 4nu3) = 1.70 x 10(-22), and SV(3nu1 + 2nu2) = 0.49 x 10(-22) cm-1/molecule cm-2 at 296 K, which correspond to a cutoff of 10(-26) cm-1/molecule cm-2.

Evidence for colocalization of GABA and glycine in afferents to retrogradely labelled rat abducens motoneurones

The coexistence of gamma-aminobutyric acid (GABA) and glycine in axon terminals impinging on rat abducens motoneurones was investigated using a double staining procedure combining retrograde labelling of the motoneurones with HRP and post-embedding immunocytochemical staining of axon terminals. Adjacent ultrathin sections of cell bodies of identified motoneurones were individually treated with GABA or glycine antibodies. The terminals single labelled for GABA represented 11.4% of the terminals analyzed, while 8% of them were glycine immunoreactive and 9% were both GABA and glycine immunoreactive. All the labelled terminals contained pleomorphic vesicles. The mean length of apposition of the double labelled terminals was statistically larger (2.20 +/- 0.97 microns) than the GABA (1.65 +/- 0.57 microns) or glycine immunoreactive ones (1.37 +/- 0.35 microns).

Clonazepam in acute mania: time-blind evaluation of clinical response and concentrations in plasma

This study was performed to evaluate the optimal doses and clinical efficacy of clonazepam as a first-line drug in acute mania, as well as to determine its effective plasma concentrations. Clonazepam was administered orally to 11 newly admitted inpatients. On day 0, the loading dose was titrated upward according to the clinical global impression; the maintenance dose was calculated with intent to maintain the plasma level that had been achieved after initial dose escalation. Clinically based dose adjustments were allowed on days 4 and 7. Manic symptoms were scored on days 0, 4 and 14 according to a time-blind procedure; clonazepam plasma levels were measured by HPLC. On day 14, there was a significant decrease in manic symptoms and 66.7% of the patients who completed the trial were markedly improved. Steady-state plasma levels of clonazepam were significantly correlated with daily doses (rs = 0.795, P < 0.005) and therapeutic concentrations ranged between 6.5-83.9 micrograms/l. At the onset of therapy, the clinically titrated loading dose resulted in plasma concentrations within the narrow range of 18.9-34.0 micrograms/l. These results support the potential value of clonazepam in the short-term management of acute mania; the initial control of agitation was achieved with plasma drug levels in a remarkably narrow range as compared with the further control of mania.

GABAergic innervation of rat abducens motoneurons retrogradely labelled with HRP: quantitative ultrastuctural analysis of cell bodies and proximal dendrites

In this quantitative electron microscopic study we investigated the distribution of GABA axon terminals on rat abducens motoneurons by combining retrograde labelling of montoneurons with post-embedding immunodetection of GABA. We analysed the synapses on 13 cell bodies and 60 proximal dendritic profiles distributed along the entire rostro-caudal extent of the nucleus. For each of these two compartments, we analysed 1754 and 1176 axon terminals in contact with 6042 and 3299 microns of postsynaptic membrane. The axon terminals were classified as Sv-type (containing spherical vesicles) or Pv-type (containing pleomorphic vesicles). The GABAergic terminals contained pleomorphic vesicles and established mainly symmetrical synaptic contacts. Their apposition lengths were greater than those of unlabelled terminals. On cell bodies, the percentage of GABAergic synaptic covering varied from 2.5% to 14.1% and the synaptic frequency of GABAergic axon terminals varied from 0.6% to 8.9%. These two parameters were significantly correlated with the diameter of the motoneurons. The percentage of synaptic covering and synaptic frequency were smaller on dendrites of small motoneurons than on those of large ones. The proximal dendrites of small motoneurons had a lesser GABAergic innervation than large ones. The total synaptic covering and frequency were smaller on somata than on dendrites. However, the percentage of synaptic covering by GABA terminals was higher on cell bodies than on proximal dendrites.

Ultrastructural organization of the interstitial subnucleus of the nucleus of the tractus solitarius in the cat: identification of vagal afferents

This electron microscopic study, based on serial section analysis, describes the synaptic organization of the interstitial subnucleus of the nucleus of the solitary tract and identifies the terminals of the vagal primary afferents utilizing degeneration and HRP transport. The interstitial subnucleus contains sparsely scattered cell bodies, numerous dendrites and axon terminals, and bundles of unmyelinated and myelinated axons. The cell bodies which are small in diameter have an organelle poor cytoplasm and a large invaginated nucleus. Axon terminals can be classified into two main types according to their vesicular shape. The first type contains clear, round vesicles and can be further subdivided into two subgroups on the basis of their morphology and the size of their vesicles. In the first subgroup the terminals are small, contain a few mitochondria and their vesicles are densely packed with an homogeneous size. In the second subgroup the terminals which vary from small to large, contain many mitochondria and contain round vesicles which are heterogeneous in size. The second main terminal type consists of axon terminals containing pleomorphic vesicles which are associated with asymmetrical or symmetrical synaptic contacts on dendrites. Axo-axonic contacts are present in the interstitial subnucleus. In general, the presynaptic axon terminals contain pleomorphic vesicles and the postsynaptic elements contain round vesicles of varying size. In some dendrites, identified by the presence of ribosomes, groups of round and/or pleomorphic vesicles are found associated with synaptic contacts. These dendrites are presynaptic to conventional dendrites and postsynaptic to axon terminals. After removal of the nodose ganglion, degenerative alterations are seen only at the caudal and middle levels of the interstitial subnucleus. Degeneration occurs in a few myelinated axons and in axon terminals which usually contain a mixture of small and larger round, clear vesicles. After HRP injection into the vagus nerve, the HRP reaction product is visible in axon terminals filled with clear, round vesicles which are heterogeneous in size. The labelled axon terminals establish single or multiple synaptic contacts. This study demonstrates that terminals of vagal primary afferents consist principally of terminals of the second subgroup. The morphology of these terminals are compared to primary afferents in the brainstem and spinal cord.

Pressure shifts of O(3) broadened by N(2) and O(2)

High resolution infrared spectra of O(3) have been recorded with an FT spectrometer at Reims University with a resolution of 0.002 cm(-1) and a SNR of the order of 800. The 2100-cm(-1) region corresponding to the v(1) + v(3) band has been analyzed. A large number of spectra, with ozone pressure varying from 5 to 50 Torr and foreign gas from 80 to 700 Torr, were recorded. The CO lines were recorded simultaneously and used as the standard to obtain the shifts, which have been measured for about 150 lines. We note a linear variation of the shifts with the J quantum number.

The HITRAN database: 1986 edition

A description and summary of the latest edition of the AFGL HITRAN molecular absorption parameters database are presented. This new database combines the information for the seven principal atmospheric absorbers and twenty-one additional molecular species previously contained on the AFGL atmospheric absorption line parameter compilation and on the trace gas compilation. In addition to updating the parameters on earlier editions of the compilation, new parameters have been added to this edition such as the self-broadened halfwidth, the temperature dependence of the air-broadened halfwidth, and the transition probability. The database contains 348043 entries between 0 and 17,900 cm(-1). A FORTRAN program is now furnished to allow rapid access to the molecular transitions and for the creation of customized output. A separate file of molecular cross sections of eleven heavy molecular species, applicable for qualitative simulation of transmission and emission in the atmosphere, has also been provided.

AFGL atmospheric absorption line parameters compilation: 1982 edition

The latest edition of the AFGL atmospheric absorption line parameters compilation for the seven most active infrared terrestrial absorbers is described. Major modifications to the atlas for this edition include updating of water-vapor parameters from 0 to 4300 cm(-1), improvements to line positions for carbon dioxide, substantial modifications to the ozone bands in the middle to far infrared, and improvements to the 7- and 2.3-microm bands of methane. The atlas now contains approximately 181,000 rotation and vibration-rotation transitions between 0 and 17,900 cm(-1). The sources of the absorption parameters are summarized.