Increasing F2-isoprostanes in the first month after birth predicts poor respiratory and neurodevelopmental outcomes in very preterm infants.

OBJECTIVE: This study examined the association between increased early oxidative stress, measured by F2-isoprostanes (IsoPs), and respiratory morbidity at term equivalent age and neurological impairment at 12 months of corrected age (CA). STUDY DESIGN: Plasma samples were collected from 136 premature infants on days 14 and 28 after birth. All participants were infants born at ⩽28 weeks of gestational age enrolled into the Prematurity and Respiratory Outcomes Program (PROP) study. Respiratory morbidity was determined at 40 weeks of postmenstrual age (PMA) by the Respiratory Severity Index (RSI), a composite measure of oxygen and pressure support. Neurodevelopmental assessment was performed using the Developmental Assessment of Young Children (DAYC) at 12 months of CA. Multivariable logistic regression models estimated associations between IsoP change, RSI and DAYC scores. Mediation analysis was performed to determine the relationship between IsoPs and later outcomes. RESULTS: Developmental data were available for 121 patients (90% of enrolled) at 12 months. For each 50-unit increase in IsoPs, regression modeling predicted decreases in cognitive, communication and motor scores of -1.9, -1.2 and -2.4 points, respectively (P<0.001). IsoP increase was also associated with increased RSI at 40 weeks of PMA (odds ratio=1.23; P=0.01). RSI mediated 25% of the IsoP effect on DAYC motor scores (P=0.02) and had no significant impact on cognitive or communication scores. CONCLUSIONS: In the first month after birth, increases in plasma IsoPs identify preterm infants at risk for respiratory morbidity at term equivalent age and worse developmental outcomes at 12 months of CA. Poor neurodevelopment is largely independent of respiratory morbidity.

A revised and unified pressure-clamp/relaxation theory for studying plant cell water relations with pressure probes: in-situ determination of cell volume for calculation of volumetric elastic modulus and hydraulic conductivity.

The cell-pressure-probe is a unique tool to study plant water relations in-situ. Inaccuracy in the estimation of cell volume (νo) is the major source of error in the calculation of both cell volumetric elastic modulus (ε) and cell hydraulic conductivity (Lp). Estimates of νo and Lp can be obtained with the pressure-clamp (PC) and pressure-relaxation (PR) methods. In theory, both methods should result in comparable νo and Lp estimates, but this has not been the case. In this study, the existing νo-theories for PC and PR methods were reviewed and clarified. A revised νo-theory was developed that is equally valid for the PC and PR methods. The revised theory was used to determine νo for two extreme scenarios of solute mixing between the experimental cell and sap in the pressure probe microcapillary. Using a fully automated cell-pressure-probe (ACPP) on leaf epidermal cells of Tradescantia virginiana, the validity of the revised theory was tested with experimental data. Calculated νo values from both methods were in the range of optically determined νo (=1.1-5.0nL) for T. virginiana. However, the PC method produced a systematically lower (21%) calculated νo compared to the PR method. Effects of solute mixing could only explain a potential error in calculated νo of <3%. For both methods, this discrepancy in νo was almost identical to the discrepancy in the measured ratio of ΔV/ΔP (total change in microcapillary sap volume versus corresponding change in cell turgor) of 19%, which is a fundamental parameter in calculating νo. It followed from the revised theory that the ratio of ΔV/ΔP was inversely related to the solute reflection coefficient. This highlighted that treating the experimental cell as an ideal osmometer in both methods is potentially not correct. Effects of non-ideal osmotic behavior by transmembrane solute movement may be minimized in the PR as compared to the PC method.

The relationship between root hydraulics and scion vigour across Vitis rootstocks: what role do root aquaporins play?

Vitis vinifera scions are commonly grafted onto rootstocks of other grape species to influence scion vigour and provide resistance to soil-borne pests and abiotic stress; however, the mechanisms by which rootstocks affect scion physiology remain unknown. This study characterized the hydraulic physiology of Vitis rootstocks that vary in vigour classification by investigating aquaporin (VvPIP) gene expression, fine-root hydraulic conductivity (Lp(r)), % aquaporin contribution to Lp(r), scion transpiration, and the size of root systems. Expression of several VvPIP genes was consistently greater in higher-vigour rootstocks under favourable growing conditions in a variety of media and in root tips compared to mature fine roots. Similar to VvPIP expression patterns, fine-root Lp(r) and % aquaporin contribution to Lp(r) determined under both osmotic (Lp(r)(Osm)) and hydrostatic (Lp(r)(Hyd)) pressure gradients were consistently greater in high-vigour rootstocks. Interestingly, the % aquaporin contribution was nearly identical for Lp(r)(Osm) and Lp(r)(Hyd) even though a hydrostatic gradient would induce a predominant flow across the apoplastic pathway. In common scion greenhouse experiments, leaf area-specific transpiration (E) and total leaf area increased with rootstock vigour and were positively correlated with fine-root Lp(r). These results suggest that increased canopy water demands for scion grafted onto high-vigour rootstocks are matched by adjustments in root-system hydraulic conductivity through the combination of fine-root Lp(r) and increased root surface area.

Evaluation of CO2-based cold sterilization of a model hydrogel.

The purpose of the present work is to evaluate a novel CO(2)-based cold sterilization process in terms of both its killing efficiency and its effects on the physical properties of a model hydrogel, poly(acrylic acid-co-acrylamide) potassium salt. Suspensions of Staphylococcus aureus and Escherichia coli were prepared for hydration and inoculation of the gel. The hydrogels were treated with supercritical CO(2) (40 degrees C, 27.6 MPa). The amount of bacteria was quantified before and after treatment. With pure CO(2), complete killing of S. aureus and E. coli was achieved for treatment times as low as 60 min. After treatment with CO(2) plus trace amounts of H(2)O(2) at the same experimental conditions, complete bacteria kill was also achieved. For times less than 30 min, incomplete kill was noted. Several physical properties of the gel were evaluated before and after SC-CO(2) treatment. These were largely unaffected by the CO(2) process. Drying curves showed no significant change between treated (pure CO(2) and CO(2) plus 30% H(2)O(2)) and untreated samples. The average equilibrium swelling ratios were also very similar. No changes in the dry hydrogel particle structure were evident from SEM micrographs.

Leaf scorch symptoms are not correlated with bacterial populations during Pierce's disease.

Xylella fastidiosa (Xf) is a xylem-limited bacterium that lives as a harmless endophyte in most plant species but is pathogenic in several agriculturally important crops such as coffee, citrus, and grapevine (Vitis vinifera L.). In susceptible cultivars of grapevine, Xf infection results in leaf scorch, premature leaf senescence, and eventually vine death; a suite of symptoms collectively referred to as Pierce's disease. A qPCR assay was developed to determine bacterial concentrations in planta and these concentrations were related to the development of leaf-scorch symptoms. The concentration of Xf in leaves of experimental grapevines grown in the greenhouse was similar to the concentration of Xf in leaves of naturally infected plants in the field. The distribution of Xf was patchy within and among leaves. Some whole leaves exhibited severe leaf-scorch symptoms in the absence of high concentrations of Xf. Despite a highly sensitive assay and a range of Xf concentrations from 10(2) to 10(9) cells g(-1) fresh weight, no clear relationship between bacterial population and symptom development during Pierce's disease was revealed. Thus, high and localized concentrations of Xf are not necessary for the formation of leaf-scorch symptoms. The results are interpreted as being consistent with an atiology that involves a systemic plant response.

Compatibility of Medical-Grade Polymers with Dense CO(2).

This study reports the effect of exposure to liquid carbon dioxide on the mechanical properties of selected medical polymers. The tensile strengths and moduli of fourteen polymers are reported. Materials were exposed to liquid CO(2), or CO(2) + trace amounts of aqueous H(2)O(2), at 6.5 MPa and ambient temperature. Carbon dioxide uptake, swelling, and distortion were observed for the more amorphous polymers while polymers with higher crystallinity showed little effect from CO(2) exposure. Changes in tensile strength were not statistically significant for most plastics, and most indicated good tolerance to liquid CO(2). These results are relevant to evaluating the potential of liquid CO(2)-based sterilization technology.

Biocompatibility of supercritical CO2-treated titanium implants in a rat model.

Supercritical phase CO2 is a promising method for sterilizing implantable devices and tissue grafts. The goal of this study is to evaluate the biocompatibility of titanium implants sterilized by supercritical phase CO2 in a rat subcutaneous implantation model. At 5 weeks post implantation titanium implants sterilized by supercritical phase CO2 produce a soft tissue reaction that is comparable to other methods of sterilization (steam autoclave, ultraviolet light radiation, ethylene oxide gas, and radio-frequency glow-discharge), as indicated by the thickness and density of the foreign body capsule, although there were some differences on the capillary density. Overall the soft tissue response to the implants was similar among all methods of sterilization, indicating supercritical phase CO2 treatment did not compromise the biocompatibility of the titanium implant.

Effects of sterilization on implant mechanical property and biocompatibility.

This article concisely reviews the effects of sterilization on the mechanical properties and surface chemistries of implantable biomaterials. This article also summarizes the biological effects of the sterilization-related changes in the implant. Because there are so many different types of implant materials currently in use (including metals, polymers, and diverse biological materials), the response of tissue to these different materials varies dramatically. This review further discusses the effects of sterilization on in vivo and in vitro tissue response specifically to implantable metals and polyethylene, with the possibility of future biocompatibility testing of the implants sterilized with supercritical phase carbon dioxide sterilization.

Structural diversity in metal ion chelation and the structure of uroporphyrinogen III synthase.

All tetrapyrroles are synthesized through a branched pathway, and although each tetrapyrrole receives unique modifications around the ring periphery, they all share the unifying feature of a central metal ion. Each pathway maintains a unique metal ion chelatase, and several tertiary structures have been determined, including those of the protoporphyrin ferrochelatase from both human and Bacillus subtilus, and the cobalt chelatase CbiK. These enzymes exhibit strong structural similarity and appear to function by a similar mechanism. Met8p, from Saccharomyces cerevisiae, catalyses ferrochelation during the synthesis of sirohaem, and the structure reveals a novel chelatase architecture whereby both ferrochelation and NAD(+)-dependent dehydrogenation take place in a single bifunctional active site. Asp-141 appears to participate in both catalytic reactions. The final common biosynthetic step in tetrapyrrole biosynthesis is the generation of uroporphyrinogen by uroporphyrinogen III synthase, whereby the D ring of hydroxymethylbilane is flipped during ring closure to generate the asymmetrical structure of uroporphyrinogen III. The recently derived structure of uroporphyrinogen III synthase reveals a bi-lobed structure in which the active site lies between the domains.

Changes in grape seed polyphenols during fruit ripening.

The quantity and characterization of extracted flavan-3-ol monomers and procyanidins was determined in seeds from Vitis vinifera cv. Cabernet Sauvignon berries, over the course of ripening and at different levels of vine water status. The per berry extractive yield of all polyphenols decreased with maturity, and followed second-order kinetics. The flavan-3-ol monomers decreased most rapidly, followed by the procyanidin extension units and finally, the terminal units. The relative proportion of procyanidin extension units did not vary with maturity. During fruit ripening, the mean degree of polymerization of extracted procyanidins is unchanged when analyzed intact by HPLC, but decreases by thiolytic degradation. The proportion of extracted procyanidins resistant to acid catalyzed thiolysis increased with maturity. Changes in vine water status affected polyphenol amounts, indicating that cultural practices can be used to influence composition. Oxidation of the seed polyphenols during fruit ripening, could explain these observations.

Comparison between supercritical carbon dioxide extraction and aqueous surfactant washing of an oily machining waste.

Mathematical models are developed to compare aqueous surfactant washing to supercritical carbon dioxide (SCCO2) extraction. These two cleaning processes are potentially competitive technologies which can be used to remove oily contaminants from a solid waste. In both processes, the cleaning efficiency for a batch of waste is evaluated by quantifying the residual oil content in the treated sample. A mass transfer model is used to simulate a semi-continuous washing process, and the experimental data, obtained in a batch operation, are used to estimate the equilibrium parameters in the model. For SCCO2 extraction, a linear desorption model is used to describe the supercritical desorption of oil from the solid phase into the CO2 phase and the simulated results agreed very well with the experimental data. The oil removal in aqueous surfactant washing is viewed to be controlled primarily by the diffusional transport of oil from the interiors of the waste elements to the surface, thus, it can be significantly affected by the size of the particles. A pre-cleaning pulverization is then recommended to improve the cleaning efficiency without increasing any other operation costs. In SCCO2 extraction, the desorption of oil from the solid waste is the controlling step and consequently, the solvent flow rate has no influence on oil removal. Our theoretical studies show that the difference between the cleaning efficiencies of these two technologies is not significant, with the oil concentration in the washing products approximately 5% lower than that in the extraction products.

The impact of federal and state laws on children exposed to domestic violence.

Until recently, few federal and state laws specifically addressed the needs of children in families in which there is domestic violence. Yet, many laws, particularly in the areas of domestic violence, family law, child welfare, welfare reform, and immigration, can have profound effects on the well-being of these children. The growing understanding by legislators and policymakers of the potential harms of domestic violence to children has resulted in recent years in statutory changes, particularly at the state level. However, laws that are enacted and implemented with inadequate knowledge of the complex dynamics of domestic violence and the unique issues battered parents and their children face may have unintended negative consequences for the children these laws are designed to protect. Collaboration across public and private social service agencies and domestic violence training for court personnel are examples of efforts that can bridge this knowledge gap and increase the likelihood that the protective intent of the laws is carried out in practice. This article analyzes current and proposed federal and state civil laws to better understand their potential impact on children affected by domestic violence. A companion article by Lemon in this journal issue examines court decisions related to these laws.

Focal brain injury and its effects on cerebral mantle, neurons, and fiber tracks.

Following a mild cortical impact injury delivered by a piston to the right sensorimotor cortex of the anesthetized rat, we evaluated mantle loss, neuronal changes, and fiber track degeneration by deOlmos silver stains up to 8 weeks after injury. Darkened neurons indicating damage (chromatolysis) occurred widely throughout both hemispheres and were seen from 1 h to 8 weeks after injury. This effect might have occurred from pressure wave damage from piston impact, brain displacement or deafferentation. Cerebral mantle loss was variable but fiber track degeneration related to projection and corticofugal descending tracks associated with the right sensorimotor system was rather constant. Unexpectedly, considerable fiber track degeneration occurred within the cerebellum, especially the inferior vermis. Cells directly under the piston face were surprisingly well-preserved but axon degeneration studies showed that these apparently intact neuronal cell bodies were surrounded by a dense network of degenerating fiber tracks. The intact cells, therefore, may have been functionally cut off from the rest of the brain owing to interruption of their efferents and afferents. The increased susceptibility of axons compared to cell bodies seen with this focal injury is similar to that observed with diffuse brain injury. The early appearing, severe and widespread axon damage we observed suggests that amelioration of focal traumatic brain injury will have to be directed promptly to the preservation of axons as well as cell bodies.

Reference memory and allocentric spatial localization deficits after unilateral cortical brain injury in the rat.

Traumatic brain injury (TBI) produces learning and memory impairments in humans. This study investigated the effects of TBI on memory and spatial localization strategies in rats. Prior to TBI, separate groups of rats were trained in an 8-arm radial maze with either all 8 arms baited (Expt. 1) or only 4 of the 8 arms baited (Expt. 2). TBI was produced by a controlled pneumatic impactor striking the entire right sensorimotor cortex of the anesthetized rat. Rats used in Expt. 1 were selected because they did not use a stereotypic response strategy (going to adjacent arms) in performing the maze before injury. After TBI the rats were not different from control rats in the number of working memory (WM) errors made. They did, however, display a distinct propensity to go to adjacent arms, i.e., exhibit stereotypic behavior, with a right-handed (ipsiversive) bias (P < 0.005). After TBI, rats which were trained with only 4 of 8 arms baited committed more reference memory (RM) errors than control rats (P < 0.05). They did not differ from controls on WM errors. Injured rats took longer to re-attain criteria than controls (P < 0.0001). Injured rats also initially displayed a propensity to enter the adjacent arm sequentially before re-attaining criteria. Further analysis indicated that injured rats re-learned the maze with a right-hand bias (P < 0.0001). The results of both experiments suggest that after TBI, rats shifted from an allocentric to an egocentric strategy to re-learn the maze. It was suggested that damage to the parietal cortex may have been responsible for both RM errors and the shift away from an allocentric strategy to an egocentric strategy. Possibly, the ipsiversive (right-hand) bias may be the result of a behaviorally or injury-induced neurochemical asymmetry within the motor system.

Traumatic brain injury of the forelimb and hindlimb sensorimotor areas in the rat: physiological, histological and behavioral correlates.

This study characterizes physiological, histological and behavioral effects of traumatic brain injury (TBI) produced by a controlled pneumatic impactor striking the entire right sensorimotor cortex of the anesthetized rat. Damage to both the fore- and hindlimb sensorimotor areas resulted in a hemiparetic animal which allowed us to use four sensitive behavioral/neurological tests to track the recovery sequelae after injury. Initial experiments measured cardiovascular and respiratory effects after cortical impact which depressed the dura to varying depths. Both 0.5 mm and 1 mm cortical depressions produced a momentary decrease (P < 0.05) in mean arterial blood pressure (MABP) while cortical impacts to depths of 2 mm or 3 mm produced a momentary increase (P < 0.05) in MABP. Normotension was re-established within 30 s after the initial response at all injury levels. Respiratory rate was affected only following 3 mm cortical depressions. A 1 mm cortical depression appeared ideal in terms of minimal cardiorespiratory effects, low mortality and lasting behavioral effects. For behavioral and histologic studies, therefore, additional rats were injured by a 1 mm cortical impact and tested for 8 weeks after TBI using four behavioral tests. Injured rats displayed both fore- and hindlimb deficits up to 56 days while traversing a narrow beam (P < 0.001) and up to 28 days when crossing a pegged beam (P < 0.05). Forelimb deficits evaluated on a wire grid platform were evident for 28 days (P < 0.05). Forepaw preference measured in a non-test setting indicated a bias to use the unaffected forepaw for 35 days (P < 0.05). A biphasic pattern of functional recovery was seen on all tests. A period of rapid functional recovery lasting 7 to 10 days was followed by a slower period of functional recovery lasting many weeks. Possible meanings of this biphasic recovery are discussed as issues of behavioral compensation/adaptation versus true neural recovery. Eight weeks after TBI histological analyses indicated that axonal degeneration was present in the areas adjacent to the ipsilateral cortical injury site. Degenerating fibers also extended across the corpus callosum into the homologous area in the contralateral cortex and were seen in the ipsilateral striatum, somatosensory and motor thalamic nuclei and substantia nigra. Significant axonal degeneration occurred bilaterally around the deep cerebellar nuclei. Degenerating fibers extended into the folia and terminated in the cerebellar granule cell layer. Thus the entire sensorimotor control system appeared to have been affected by a cortical injury.

Transactivation by the human T-cell leukemia virus Tax protein is mediated through enhanced binding of activating transcription factor-2 (ATF-2) ATF-2 response and cAMP element-binding protein (CREB).

The human T-cell leukemia virus type I (HTLV-I)-encoded transcriptional activator protein Tax is strongly implicated in HTLV-I pathogenesis. Tax regulates HTLV-I gene expression through three 21-base pair (bp) repeat enhancer elements located in the transcriptional control region of the virus. Tax does not bind these elements directly, but mediates transactivation through the cellular transcription factors that recognize a cAMP response element (CRE)-like sequence centered within each of the 21-bp repeats. In this report, we identify activating transcription factor-2 (ATF-2) and CRE-binding protein (CREB) as the principal T-cell proteins that bind the three 21-bp repeats in vitro. Purified Tax protein augments the level of RNA synthesis induced by ATF-2 and CREB in a cell-free transcription assay, providing evidence that Tax cooperates with these cellular proteins to activate HTLV-I transcription. Furthermore, Tax dramatically increases the binding of both the T-cell-derived and recombinant forms of ATF-2 and CREB to each of the 21-bp repeats. The target sequences for this enhancement reside within the DNA binding/dimerization domains of these proteins. These data suggest that Tax transactivates HTLV-I gene expression by increasing the number of bound ATF-2 and CREB molecules at the viral promoter.

Rapid Changes in Cell Wall Yielding of Elongating Begonia argenteo-guttata L. Leaves in Response to Changes in Plant Water Status.

Elongation and epidermal cell turgor (P) of Begonia argenteoguttata L. leaves were simultaneously measured to determine the wall-yielding behavior of growing leaf cells in response to changes in plant water status. Rapid changes in plant water status were imposed by irrigating the rooting media with solutions of -0.20 and -0.30 MPa mannitol. These treatments caused decreases in P of 0.09 and 0.17 MPa, respectively. The decreases in P were complete within 10 min, and P did not change thereafter. Following treatments, leaf elongation was nil for periods of 25 to 38 min. Subsequently, elongation recovered to steady rates that were 45 or 75% lower than in the well-watered controls. Leaves of plants that were pretreated with -0.30 MPa of mannitol and rewatered showed an increase in P of 0.19 MPa, which was complete within 15 min; P did not change thereafter. Rewatering caused a several-fold increase in leaf elongation rates, which subsequently declined while P was increasing, to reach steady rates similar to that of the controls. Several estimates of elastic deformation indicated that most of the elongation responses to altered P were due to changes in irreversible deformation. The results showed that the initial effects of changes in P on leaf elongation were partially compensated for by changes in the cell wall-yielding properties. We conclude that linear relationships between P and adjusted growth rates are not necessarily indicative of constant wall-yielding properties. Instead, these relationships may reflect the effect of P on wall-loosening processes.

In vitro activation of transcription by the human T-cell leukemia virus type I Tax protein.

The human T-cell leukemia virus type I (HTLV-I) regulatory protein Tax activates transcription of the proviral long terminal repeats and a number of cellular promoters. We have developed an in vitro system to characterize the mechanism by which Tax interacts with the host cell transcription machinery. Tax was purified from cells infected with a baculovirus expression vector. Addition of these Tax preparations to nuclear extracts from uninfected human T lymphocytes activated transcription of the HTLV-I long terminal repeat approximately 10-fold. Transcription-stimulatory activity copurified with the immunoreactive 40-kDa Tax polypeptide on gel filtration chromatography, and, as expected, the effect of recombinant Tax was diminished in HTLV-I-infected T-lymphocyte extracts containing endogenous Tax. Tax-mediated transactivation in vivo has been previously shown to require 21-bp-repeat Tax-responsive elements (TxREs) in the promoter DNA. Stimulation of transcription in vitro was also strongly dependent on these sequences. To investigate the mechanism of Tax transactivation, cellular proteins that bind the 21-bp-repeat TxREs were prepared by DNA affinity chromatography. Recombinant Tax markedly increased the formation of a specific host protein-DNA complex detected in an electrophoretic mobility shift assay. These data suggest that Tax activates transcription through a direct interaction with cellular proteins that bind to the 21-bp-repeat TxREs.

Selective deafferentation of convergent inputs to trigeminal subnucleus caudalis: effects on calcitonin gene-related peptide distribution.

Electrophysiological studies (Sessle, 1987, 1991) suggest that trigeminal deafferenting injuries can cause an "unmasking" of existing but normally suppressed convergent inputs to the spinal trigeminal nucleus, including many that arise from the cervical spinal cord. However, the spatial arrangement of this projection has not been examined, particularly with reference to nociceptive components that might become involved in pathological changes leading to chronic pain. Therefore, the purpose of this study was to apply selective interruptions of the trigeminal and/or cervical primary afferent inputs to the spinal trigeminal subnucleus caudalis (Vc) in the cat, followed by (1) demonstration and quantification of axonal degeneration in the spinal trigeminal tract to determine the extent of trigeminal-cervical primary afferent overlap; and (2) an analysis of lesion-induced alterations in the distribution of calcitonin gene-related peptide immunoreactivity (CGRP-IR) in laminae I and II of Vc, since recent evidence strongly suggests that CGRP is involved in pathophysiological elevations of central nervous system neuronal excitability. Degenerating fibers were found throughout the spinal tract following a trigeminal rhizotomy or tractotomy, with the largest numbers adjacent to the rostral two-thirds of Vc, but with a significant number extending caudally to at least the level of C2. CGRP-IR was reduced or eliminated from the rostral one-third and periobex region of Vc, except for a dorsomedial zone that was minimally affected. Retention of CGRP-IR was greater at more caudal levels. Following a combined trigmeninal and cervical tractotomy, fiber degeneration was massive throughout the spinal tract, yet a population of small myelinated fibers persisted at 60 days after surgery. Concomitantly, CGRP-IR was profoundly reduced throughout Vc, except for a small dorsomedial zone of retention, which became more extensive caudally. A cervical tractotomy resulted in moderate numbers of degenerating fibers adjacent to the caudal one-third of Vc, and this number declined rostrally; however, degenerating fibers could be seen at the level of the obex. CGRP-IR was reduced in the dorsomedial and ventrolateral zones of Vc, particularly in its caudal one-third. Electron-microscopic analysis revealed a population of CGRP-IR boutons, most of which were of the simple axodendritic type with asymmetrical contacts. A few examples of axoaxonic contacts were observed. Loss of labeled boutons observed with the electron microscope was consistent with light-microscopic quantitative results. Those boutons that were retained were variable in size and displayed simple axodendritic contacts.(ABSTRACT TRUNCATED AT 400 WORDS)