Analysis of human T cell and B cell responses against U small nuclear ribonucleoprotein 70-kd, B, and D polypeptides among patients with systemic lupus erythematosus and mixed connective tissue disease

OBJECTIVE

To analyze T and B cell reactivity with U small nuclear RNP (snRNP) 70-kd, B, and D polypeptides among patients with connective tissue disease (CTD) and to examine the functional characteristics of snRNP-reactive T cell clones.

METHODS

We used an snRNP enzyme-linked immunosorbent assay and immunoblotting to characterize antibodies in patients' sera. We used human recombinant fusion proteins 70 kd, B, and D to stimulate and clone snRNP-reactive T cells from CTD patients. We analyzed the cell surface phenotype, antigenic specificity, and cytokine profiles of T cell clones.

RESULTS

Patients showed T cell responsiveness to snRNP polypeptides that paralleled their autoantibody reactivities. A total of 256 clones were generated, and clones were identified which were specific for the 70-kd, B, or D polypeptides. Clones expressed a T helper cell phenotype, and were found to produce substantial quantities of both interleukin-4 (IL-4) and interferon-gamma, and lesser quantities of IL-2 and IL-6.

CONCLUSION

These results show that CTD patients have clonable circulating snRNP-reactive T cells that parallel the specificity of snRNP-reactive antibodies in their sera. The snRNP-reactive T cells exhibit a helper cell phenotype and produce cytokines which are important in B cell help and differentiation.

Comparison and evaluation of retrospective intermodality brain image registration techniques

PURPOSE

The primary objective of this study is to perform a blinded evaluation of a group of retrospective image registration techniques using as a gold standard a prospective, marker-based registration method. To ensure blindedness, all retrospective registrations were performed by participants who had no knowledge of the gold standard results until after their results had been submitted. A secondary goal of the project is to evaluate the importance of correcting geometrical distortion in MR images by comparing the retrospective registration error in the rectified images, i.e., those that have had the distortion correction applied, with that of the same images before rectification.

METHOD

Image volumes of three modalities (CT, MR, and PET) were obtained from patients undergoing neurosurgery at Vanderbilt University Medical Center on whom bone-implanted fiducial markers were mounted. These volumes had all traces of the markers removed and were provided via the Internet to project collaborators outside Vanderbilt, who then performed retrospective registrations on the volumes, calculating transformations from CT to MR and/ or from PET to MR. These investigators communicated their transformations again via the Internet to Vanderbilt, where the accuracy of each registration was evaluated. In this evaluation, the accuracy is measured at multiple volumes of interest (VOIs), i.e., areas in the brain that would commonly be areas of neurological interest. A VOI is defined in the MR image and its centroid c is determined. Then, the prospective registration is used to obtain the corresponding point c' in CT or PET. To this point, the retrospective registration is then applied, producing c" in MR. Statistics are gathered on the target registration error (TRE), which is the distance between the original point c and its corresponding point c".

RESULTS

This article presents statistics on the TRE calculated for each registration technique in this study and provides a brief description of each technique and an estimate of both preparation and execution time needed to perform the registration.

CONCLUSION

Our results indicate that retrospective techniques have the potential to produce satisfactory results much of the time, but that visual inspection is necessary to guard against large errors.

Metabolism of 14C-labelled sucrose esters of stearic acid in rats

Rats were dosed by oral gavage (250 mg/kg) with compounds containing sucrose esterified in four, six or eight positions with stearic acid. For each compound, rats excreted greater than 95% of the dose in the faeces. The extent of absorption and metabolism of radioactivity was inversely related to the degree of esterification. For rats dosed with sucrose esters labelled in the fatty acid moieties, the degree of absorption of radioactivity was highest for the tetraesterified compound (5.9% of the dose). At 120 hr after dosing with this derivative, the highest concentrations of radioactivity, aside from tissues of the gastrointestinal tract, were found in fat (183 micrograms-equivalents/g tissue), lymph nodes (117 micrograms-equivalents/g tissue) and the liver (88 micrograms-equivalents/g tissue); appreciable radioactivity appeared in the blood (3.9 micrograms-equivalents/g tissue) and collected lymph (5.0-7.6% of the dose). For rats dosed with esters labelled in the sucrose moiety, the amounts of radioactivity absorbed were lower than after dosing with the corresponding sucrose derivatives labelled in the fatty acid moieties; the absorbed radioactivity was greatest following administration of the tetraesterified compound (3.0%). Relatively little radioactivity was found in tissue samples collected from these rats. These results are consistent with limited hydrolysis of the sucrose esters, presumably to sucrose and fatty acids, prior to intestinal absorption.

Early prenatal critical period for chorda tympani nerve terminal field development

In order to determine whether the developing central gustatory system responds to dietary manipulation during restricted developmental periods, terminal fields of the chorda tympani nerve within the nucleus of the solitary tract were investigated via anterograde transport of horseradish peroxidase in control rats and in rats in which a low sodium diet was systematically fed during specific periods of development. Rats fed a low sodium diet (0.03% NaCl) from embryonic day 3 (E3) to day E12 and then fed a sodium replete diet to at least 60 days postnatal exhibited enlarged and irregularly shaped chorda tympani terminal fields. Specifically, the dorsal zone of the field was the smallest in controls, whereas it was the largest in restricted rats, occupying more territory within the nucleus. This alteration in the terminal field was apparent in all groups of rats fed the low-NaCl diet beginning at E3, and continuing beyond E12. In contrast, no effects of the dietary manipulation on the developing chorda tympani field was evident when it occurred from E3 to day E9, from E0 to day E9 or when it occurred at adulthood only. Therefore, only 9 days of maternal exposure to a sodium-restricted diet is required for a permanent expansion of the chorda tympani terminal field in the offspring. Moreover, a brief period from E9 to E12 must be included within the 9-day dietary restriction to yield the expanded field. Since this period is before taste receptors appear on the tongue, it is likely that nonactivity-dependent factors determine the formation of the chorda tympani terminal field during later development.

Retinyl ethers as cancer chemopreventive agents. Suppression of mammary cancer

It had been demonstrated previously that retinyl methyl ether (RME) can suppress carcinogen-induced mammary cancers in vivo. It had also been shown that RME is demethylated enzymatically to retinol and produces the toxic effects of retinol; however, a rationale was developed for further investigations of retinyl ethers and was the basis for the synthesis and biological evaluations of new retinyl ethers for the chemoprevention of mammary cancer, reported herein. Two of the new retinyl ethers, retinyl 3-methyl-2-butenyl ether (RMBE) and retinyl 2-propynyl ether (RPE), were evaluated for the suppression of mammary cancers in vivo. RMBE, RPE, RME, the 2,3,6-trimethyl-4-methoxyphenyl analogue of RME, and retinyl acetate (a positive control) were incorporated individually into the feed of rats that had been injected with N-methyl-N-nitrosourea to induce mammary cancers. Ninety-day tests of these compounds for suppression of mammary cancer showed that RPE has significant cancer chemopreventive activity, comparable to that of retinyl acetate in simultaneous tests. RMBE demonstrated borderline activity. Both RPE and RMBE were less toxic than retinyl acetate or RME and, in contrast to the other retinoids, did not cause accumulation of large amounts of retinyl palmitate in the liver. Further investigations of RPE showed that it accumulated in mammary tissue after a single oral dose was administered to female rats, reached maximum concentrations within 24 h, and was still present at 75-80% of maximum concentrations after 72 h. In ethanol at 25 degrees C, RPE slowly underwent intramolecular cyclization; small amounts of the cyclized product also appeared in mammary tissue of rats dosed with RPE. During the mammary cancer bioassay, however, RPE was essentially stable in the feed. Some of the new retinyl ethers, as well as RME, bind to cellular retinol-binding protein.

Nonenzymatic isomerization of 9-cis-retinoic acid catalyzed by sulfhydryl compounds

Certain thiol-containing compounds catalyze, in a chemical reaction, the isomerization of 9-cis-retinoic acid to a mixture of all-trans-retinoic acid, 9-cis-retinoic acid, 13-cis-retinoic acid, and 9,13-dicis-retinoic acid. In the presence of such catalysts, all-trans-retinoic acid gives rise to the same mixture. Reactions approaching equilibrium contain more all-trans-retinoic acid than either of the other isomers. Small molecules effective as catalysts are mercaptoethanol, L-cysteine methyl ester, glutathione, and N-acetyl-L-cysteine. Apoferritin (a thiol-containing protein), native microsomes, and, to a lesser extent, boiled microsomes catalyze the reaction. In intact cells, these interconversions also occur in a process inhibited by a sulfhydryl-specific reagent. The thiol-catalyzed isomerization of 9-cis-retinoic acid may be relevant in the biological activity of this compound.

New perspectives in a gustatory physiology: transduction, development, and plasticity

Major advances in the understanding of mammalian gustatory transduction mechanisms have occurred in the past decade. Recent research has revealed that a remarkable diversity of cellular mechanisms are involved in taste stimulus reception. These mechanisms range from G protein-and second messenger-linked receptor systems to stimulus-gated and stimulus-admitting ion channels. Contrary to widely held ideas, new data show that some taste stimuli interact with receptive sites that are localized on both the apical and basolateral membranes of taste cells. Studies of taste system development in several species indicate that the transduction pathways for some stimuli are modulated significantly during the early postnatal period. In addition, recent investigations of adult peripheral gustatory system plasticity strongly suggest that the function of the Na+ sensing system can be modulated by circulating hormones, growth factors, or cytokines.

Automated three-dimensional registration of magnetic resonance and positron emission tomography brain images by multiresolution optimization of voxel similarity measures

Approaches using measures of voxel intensity similarity are showing promise in fully automating magnetic resonance (MR) and positron emission tomography (PET) image registration in the head, without requiring extraction and identification of corresponding structures. In this paper a method of multiresolution optimization of these measures is described and five alternative measures are compared: cross correlation, minimization of corresponding PET intensity variation, moments of the distribution of values in the intensity feature space, entropy of the intensity feature space and mutual information. Their ability to recover registration is examined for ten clinically acquired image pairs with respect to the size of initial misregistration, the precision of the final result, and the accuracy assessed by visual inspection. The mutual information measure proved the most robust to initial starting estimate, successfully registering 98.8% of 900 trial misregistrations. Success is defined as providing a visually acceptable solution to a trained observer. A high resolution search (1/16 mm step size) of 30 trial misregistrations showed that optimization using the mutual information measure provided solutions with 0.13 mm, 0.11 mm and 0.17 mm standard deviations in the three Cartesian axes of the translation vector and 0.2 degree, 0.3 degree and 0.2 degree standard deviations for rotations about the three axes. The algorithm takes between 4 and 8 minutes to run on a typical workstation, including visual inspection of the result.

Novel regulation of peripheral gustatory function by the immune system

Soon after adult rats receive unilateral chorda tympani nerve section in combination with dietary sodium restriction, neural taste responses recorded from the intact, contralateral chorda tympani nerve are substantially reduced. We hypothesized that the immune system is compromised in sodium-restricted rats, which leads to functional alterations in the peripheral taste system after neural injury. Here, immune function was stimulated with a systemic injection of lipopolysaccharide (LPS), and neurophysiological responses were recorded from the uncut chorda tympani 4-10 days after nerve section to determine if normal sodium sensitivity was restored. Rats receiving nerve section, dietary sodium restriction, and LPS exhibited normal sodium responses. In intact rats, injection of LPS alone or LPS injection combined with sodium restriction had no effect on taste responses to sodium stimuli. Surprisingly, combining nerve section, LPS injection, and maintenance of rats on a normal diet induced supersensitive responses to sodium. These findings are the first to demonstrate that the immune system can regulate peripheral gustatory function.

Conformationally defined 6-s-trans-retinoic acid analogs. 3. Structure-activity relationships for nuclear receptor binding, transcriptional activity, and cancer chemopreventive activity

We recently demonstrated that conformationally defined 6-s-trans-retinoic acid (RA) analogs were effective in the prevention of skin papillomas (Vaezi et al. J. Med. Chem. 1994, 37, 4499-4507) and selective agonists for nuclear receptor binding and activation (Alam et al. J. Med. Chem. 1995, 38, 2302-2310). In order to probe important structure-activity relationships, we evaluated a homologous series of four 6-s-trans-retinoids that are 8-(2'-cyclohexen-1'-ylidene)-3,7-dimethyl-2,4,6-octatrienoic acids with different substituents at 2' (R2) and 3' (R1) positions on the cyclohexene ring. UAB1 (R1 = R2 = H), UAB4 (R1 = R2 = Me), UAB7 (R1 = Me, R2 = iPr), and UAB8 (R1 = Et, R2 = iPr) contain alkyl R groups that mimic, to different extents, portions of the trimethylcyclohexenyl ring of RA. Both 9Z- and all-E-isomers of these retinoids were evaluated in binding assays for cellular retinoic acid-binding proteins (CRABP-I and CRABP-II), a nuclear retinoic acid receptor (RAR alpha), and a nuclear retinoid X receptor (RXR alpha). The all-E-isomers of UAB retinoids bound tightly to CRABPs and RAR alpha, the binding affinity of the all-E-isomer increased systematically from UAB1 to UAB8, and binding for the latter was comparable to that of all-E-RA. In contrast to RA, the (9Z)-UAB retinoids were at least 200-fold less active than the all-E-isomers in binding to RAR alpha. The (9Z)-UAB isomers exhibited increasingly stronger binding to RXR alpha, and (9Z)-UAB8 was nearly as effective as (9Z)-RA in binding affinity. The retinoids were also evaluated in gene expression assays mediated by RAR alpha and RXR alpha homodimers or RAR alpha/RXR alpha heterodimers. Consistent with the binding affinities, the (all-E)-UAB retinoids activated gene transciption mediated by RAR alpha homodimers or RAR alpha/RXR alpha heterodimers, while the (9Z)-UAB isomers activated only the RXR alpha homodimer-mediated transcription. The all-E- and 9Z-isomers of the UAB retinoids were further evaluated for their capacity to prevent the induction of mouse skin papillomas. When compared to RA, only the (all-E)-UAB retinoids containing bulky R1 and R2 groups were effective in this chemoprevention assay. (9Z)-RA displayed equal capacity as RA to prevent papillomas, while the 9Z-isomers of the UAB retinoids were much less effective. Taken together, these studies demonstrate that the cyclohexenyl ring substituents of 6-s-trans-UAB retinoids are important for their biological activities and that the chemopreventive effect of the all-E-isomers of these retinoids correlates well with their capacity to bind to RARs and activate RAR/RXR-mediated transcription.

Melatonin levels in idiopathic scoliosis. Diurnal and nocturnal serum melatonin levels in girls with adolescent idiopathic scoliosis

STUDY DESIGN

Matched pairs of adolescent girls were used to compare serum melatonin levels in adolescent patients and control subjects with idiopathic scoliosis during the day and in the middle of the night.

OBJECTIVES

To compare serum melatonin levels in patients with adolescent idiopathic scoliosis and matched control subjects during the day and in the middle of the night.

SUMMARY OF BACKGROUND DATA

Recent studies using the chick as the animal model have suggested that the pineal gland and its main product, melatonin, might be involved in the cause of scoliosis. There have been no studies of melatonin levels in patients with adolescent idiopathic scoliosis.

METHODS

Blood was collected from seven adolescent girls with idiopathic scoliosis and a group of seven age-matched control subjects. Two samples were collected, one in the middle of the day and one in the middle of the night, to examine the diurnal variation of melatonin production. Serum melatonin levels were measured using a radioimmunoassay technique.

RESULTS

No significant differences were found in serum melatonin levels between experimental and control groups either during the day, when melatonin levels were low, or during the night, when melatonin levels were high.

CONCLUSIONS

Whereas pinealectomy in young chickens leads to reduced melatonin levels and the development of scoliosis, the results of this study suggest that melatonin levels in mature patients who already have severe scoliosis do not differ from healthy subjects. Whether melatonin levels differ in humans between healthy subjects and patients with scoliosis at the time of onset of the disease remains to be seen.

Murine toxicology and pharmacology of UAB-8, a conformationally constrained analog of retinoic acid

(2E, 4E, 6E)-8-[3'-Ethyl-2'-(1-methylethyl)-2'-cyclohexen-1'-ylidene] -3, 7-dimethyl-2,4,6-octatrienoic acid (UAB-8) has potent activity in preventing papillomas on the skin of mice similar to that determined in a previous study for the homolog containing one less carbon atom. To evaluate the toxicological profile for UAB-8, relative to all-trans-retinoic acid (RA), female mice were dosed by oral gavage for 29 days with amounts of 0.05, 0.1, or 0.2 mmol/kg/day. For the two compounds, the effects on body weights were similar. Mice dosed with UAB-8, however, had a lower incidence of clinical signs of toxicity (alopecia, scaly skin, and limping). At necropsy, bone fractures, skin abnormalities, and splenomegaly were observed in some mice dosed with RA but not in any dosed with UAB-8. Lymph node hyperplasia was noted in some mice dosed with either dose of RA but only in those dosed with the highest dose of UAB-8. All dose levels of RA produced microscopic lesions in the bones of mice; only the highest dose of UAB-8 had this effect. RA and UAB-8 had similar effects on chondrogenesis in cultures of cells from mouse limb buds, an indication of comparable teratogenic effects. For mice dosed i.v. (10 mg/kg), there was a saturated phase of elimination of RA from plasma (Km = 0.61 microgram/ml and Vmax = 2572 micrograms/hr); no such phase was noted when UAB-8 was administered. UAB-8 had values for t1/2 alpha and t1/2 beta of 0.47 and 17.1 hr, respectively. Relative to RA, UAB-8 has a favorable toxicological profile and different pharmacokinetics.

Retinyl methyl ether: binding to transport proteins and effect on transcriptional regulation

Retinyl methyl ether (RME) which prevents cancers of the rat mammary gland, binds to cellular retinol-binding protein and serum retinol-binding protein but not to cellular retinoic acid-binding protein or to the nuclear retinoid receptors, RARs/RXRs. Since the biochemical effects of retinoids likely involve activation or suppression of RAR/RXR-mediated gene transcription, we evaluated such activity of RME by performing cotransfection assays involving CV-1 cells, expression vectors containing RAR and/or RXR cDNA, and an appropriate reporter vector. In the concentration range of 10(-9)-10(-6), RME did not activate transcription by either of the heterodimers (RARalpha, beta or gamma/RXR alpha) or the homodimer (RARalpha/RARalpha). The retinoid, however, exhibited concentration-dependent inhibitory effects on the basal level of transcriptional activity (no other retinoid added) of both the RAR beta- and RARgamma/RXRalpha heterodimers and of the retinoic acid-induced transcriptional activation of the RARgamma/RXRalpha receptors. Thus, RME acted as a retinoic acid antagonist, a role possibly involved in its cancer preventive activity.

Automated 3-D registration of MR and CT images of the head

This paper discusses the application of voxel similarity measures in the automated registration of clinically acquired MR and CT data of the head. We describe a novel single-start multi-resolution approach to the optimization of these measures, and the issues involved in applying this to data having a range of different fields of view and sampling resolution. We compare four proposed measures of voxel similarity using the same optimization scheme when presented with 10 pairs of images with a range of initial misregistrations. The registration estimates are compared with those provided by manual point-based registration and evaluated by visual inspection to give an assessment of the robustness and accuracy of the different measures. One full-volume CT image set is used to investigate the performance of each measure when used to align truncated images from different regions in the head. The soft tissue correlation and mutual information measures were found to provide the most robust measures of misregistration, providing results comparable to or better than those from manual point-based registration for all but the most truncated image volumes.

Biochemical characteristics and differentiating activity of 4-oxo analogs of retinoic acid

3-Methyl-4-oxoretinoic acid and 3-cinnamyl-4-oxoretinoic acid bind to a cellular retinoic acid-binding protein (CRABP-II) and to a retinoic acid-receptor protein (RARa). These analogs of 4-oxoretinoic acid, as well as the parent compound, have less binding affinity than retinoic acid. Cotransfection assays in CV-1 cells with plasmids containing cDNAs for RAR alpha, RAR beta and RAR gamma (homodimers) and RAR alpha-RXR alpha and RAR beta-RXR alpha (heterodimers), indicate that 3-cinnamyl-4-oxoretinoic acid induces relatively less transcriptional activity than 4-oxoretinoic acid and its 3-methyl analog, both of which are less effective than retinoic acid. In differentiating mouse F9 embryocarcarcinoma cells, the order of effectiveness is retinoic acid > 4-oxoretinoic acid = 3-methyl-4-oxoretinoic acid > 3-cinnamyl-4-oxoretinoic acid. This order of potency is similar to that for inhibition of induction of ornithine decarboxylase (ODC) activity and for prevention of papillomas on the skin of mice. Binding to CRABP-II and activation of RARs appear to be important factors for expression of differentiating activity, inhibition of induction of ODC activity and prevention of papillomas on the skin of mice.

Time course of saline-induced recovery of the gustatory system in sodium-restricted rats

Placing pregnant rats on a Na(+)-restricted diet (0.03% NaCl) results in greatly reduced chorda tympani nerve responses to Na+ stimuli in the offspring. Normal responses can be permanently restored by providing offspring one-time access to saline. We tested whether saline-induced recovery occurs in taste receptor cells present at the time of saline intake. Chorda tympani responses were recorded 2 h, 6 h, 24 h, 10 days, and 20 days after saline ingestion. Chorda tympani Na+ responses from Na(+)-restricted rats at 2 h, 6 h, 24 h, and 10 days after saline intake were comparable to responses from control Na(+)-restricted rats. Twenty days after saline consumption, responses to Na+ were significantly elevated compared with control Na(+)-restricted rats. The results indicate that extant taste receptor cells are not substantially influenced by the saline ingestion. Instead, the delayed recovery suggests that taste receptor stem cells exclusively are influenced by saline intake.

Craniotomy guidance using a stereo-video-based tracking system

In open intracranial neurosurgery, it is desirable to minimize exposure and to approach the target in the most accurate way possible. The VISLAN system described here employs a completely passive hand-held locator which is tracked by a video system and does not require a mechanical linkage nor cables. The system also tracks easily recognizable, constant, anatomical landmarks of the patient. By this means the initial registration of pre-operative imaging and the detection of, and correction for, patient movement can be accomplished. High-resolution MRI segmented interactively is used to define external surface and brain anatomy. Thus, a pre-operative patient representation (POPR) is planned. During the surgical procedure the patient's head is illuminated by structured light and stereo-video pictures obtained from two television cameras mounted above the head. The system is calibrated and registered with the POPR using a chamfered matching algorithm. The locator is also tracked in space by the video system, and its tip position shown in relation to the POPR on the video monitor.

N-(4-hydroxyphenyl)retinamide: interactions with retinoid-binding proteins/receptors

The cellular transport, metabolism and biological activity of retinoids are mediated by their specific binding proteins and nuclear receptors. For an understanding of the mode of action of retinoids with potential cancer chemopreventive or other biological activity, it is important to study their interactions with these binding proteins and receptors. In our attempts to understand the action of N-(4-hydroxyphenyl)retinamide (4HPR) and other retinamides in the prevention of cancer, we observed that 4HPR binds to a serum protein with a molecular size of approximately 20,000. The retinoid, however, did not show any binding affinity for cellular retinol-binding protein (CRABP) or for cellular retinoic acid-binding protein (CRABP). However, it showed binding affinity for the nuclear receptors of retinoic acid (RARs) equivalent to 15% of that of retinoic acid. The physicochemical properties of the 4HPR binding protein in the serum were identical to those of serum retinol binding protein (RBP). Antibodies against RBP quantitatively immunoprecipitated the protein-4HPR complex, confirming that the retinoid specifically binds to RBP. Although retinol and 4HPR cross-competed for RBP binding, N-phenylretinamide, in which the 4-hydroxyl group is absent, and N-(4-methoxyphenyl)retinamide, a major cellular metabolite of 4HPR, in which the hydroxyl group is blocked, did not show affinity for the binding protein. The results indicate that the hydroxyl group of 4HPR is essential for binding of this type of retinoid to RBP. Thus, our studies suggest that serum transport of 4HPR may be facilitated by RBP. To bind more efficiently to CRBP, CRABP, or RARs/RXRs, the retinoid may require further metabolic change.

Cross fostering between normal and sodium-restricted rats: effects on peripheral gustatory function

Rats restricted of dietary NaCl prenatally and thereafter exhibit abnormally low electrophysiological chorda tympani taste responses to sodium stimuli as adults. Recovery of responses can be induced by ingestion of NaCl, even at adulthood. To examine whether milk from sodium-replete mothers enables functional recovery in sodium-restricted rats, we recorded multifiber chorda tympani responses in adult animals that had been cross fostered during the suckling period. Sodium-restricted animals cross fostered to control dams for postnatal weeks 1 and 2 did not recover normal sodium sensitivity. Surprisingly, control pups crossed to sodium-restricted mothers from postnatal days 1 to 14 showed an exaggerated response to NaCl as adults. These results indicate that milk from normal mothers ingested during postnatal weeks 1 and 2 is not sufficient to restore gustatory function in sodium-restricted rats. Importantly, it also appears that events occurring during the early suckling period of control rats determine long-term taste sensitivities to sodium.

The nature and distribution of the innervation of human supraspinal and interspinal ligaments

STUDY DESIGN

To use fresh, human supraspinal and interspinal ligaments and document their innervation.

OBJECTIVES

To characterize the innervation of the human supraspinal and interspinal ligaments.

SUMMARY OF BACKGROUND DATA

The nature and distribution of the innervation of spinal ligaments remains unknown.

METHODS

Sections of spinal ligaments were labeled with a fluorescent antibody against neurofilament proteins and observed with a confocal microscope.

RESULTS

The ligaments were found to be well innervated. Innervation was equally distributed along the ligament, symmetrically distributed between left and right sides, and more densely distributed in the periphery. Pacinian corpuscles were scattered randomly, close to blood vessels, whereas Ruffini corpuscles were in the periphery, close to the collagen bundles.

CONCLUSIONS

Human supraspinal and interspinal ligaments are well innervated. This innervation might form the basis of neurologic feedback mechanisms for the protection and stability of the spine. These mechanisms might also be important in the development of diseases such as scoliosis.

Immunohistochemical correlates of peripheral gustatory sensitivity to sodium and amiloride

In mammals, transduction of sodium stimuli occurs via amiloride-sensitive sodium channels. In rat, gustatory physiological sensitivity to sodium stimuli develops gradually during the early postnatal period. In addition, if pregnant rats are subjected to dietary sodium restriction during gestation, their offspring fail to develop normal gustatory physiological responses to sodium and sensitivity to amiloride. In the present study, we used polyclonal antibodies raised against amiloride-sensitive sodium channels to ascertain whether gustatory function is correlated with the immunological presence of the transduction apparatus for sodium stimuli in the taste buds of neonatal rats and adult offspring of sodium-restricted dams. The results indicate that antiamiloride-sensitive sodium channel antisera bind cells within taste buds of neonatal and adult rats, regardless of maternal dietary condition. Therefore, despite the functional absence of taste system amiloride-sensitive sodium channels, the antigenic determinants of these channels are expressed. These data suggest that the onset of normal gustatory sodium sensitivity in neonatal normal rats results from the progressive activation of existing, quiescent channels. Furthermore, they rule out the possibility that the failure to synthesize channel protein underlies the lack of gustatory sodium and amiloride sensitivity in the offspring of sodium-restricted rats.

Augmentation of reality using an operating microscope for otolaryngology and neurosurgical guidance

The operating microscope is an integral part of many neurosurgery and otolaryngology procedures; the surgeon often uses the microscopic view for a large portion of the operation. Information from preoperative radiological images is often viewed only on X-ray films. The surgeon then has the difficult task of relating this information to the appearance of the surgical view. Image guidance techniques attempt to relate these two sets of information by registering the patient in the operating room to preoperative images using locating devices. Conventionally, image data are presented on a computer monitor, which requires the surgeon to look away from the operative scene. We describe a guidance system, for procedures in which the operating microscope is used, which super-imposes image-derived data upon the operative scene. We create a model of relevant structures (e.g., tumor volume, blood vessels, and nerves) from multimodality preoperative images. By calibrating microscope optics, registering the patient to image coordinates, and tracking the microscope and patient intraoperatively, we can generate stereo projections of the three-dimensional model and project them into the microscope eyepieces, allowing critical structures to be overlaid on the operative scene in the correct position. Measurements with a head phantom gave a root mean square (RMS) error of 1.08 mm, and the estimated error for a human volunteer is between 2 and 3 mm. Initial evaluation in the operating room was very promising.

A conformationally defined 6-s-trans-retinoic acid isomer: synthesis, chemopreventive activity, and toxicity

A conformationally defined retinoic acid analog (1) which contains a dimethylene bridge to maintain the 6-s-trans orientation for two terminal double bonds in the polyene chain was synthesized. A Reformatsky reaction was utilized to extend the polyene chain of the starting enone, which provided exclusively the 9Z-configuration for the intermediate aldehyde. A Horners-Emmons condensation with this aldehyde then produced retinoic acid analogs with both 9Z- and 9Z,13Z-configurations. An I2-catalyzed isomerization of the intermediate 9Z-aldehyde yielded the all-E-aldehyde, which was olefinated as above to yield the (all-E)- and (13Z)-retinoic acid analogs of 1. Each configurational isomer of 1 was evaluated for its ability to inhibit the binding of retinoic acid to CRABP (chick skin) and to inhibit the chemical induction of ornithine decarboxylase in mouse skin. In each assay (all-E)-1 was the most active isomer, and this activity was comparable to or better than that for (all-E)-retinoic acid. (all-E)-1 and (13Z)-1 were both shown to be equally effective as (13Z)-retinoic acid in suppressing the proliferation of human sebaceous cells in vitro. (all-E)-1 was further evaluated for its ability to prevent the induction of mouse skin papillomas and to induce signs of vitamin A toxicity in mice. The cancer chemopreventive activity of (all-E)-1 was comparable to that of (all-E)-retinoic acid, and the toxicity was comparable to or slightly better than that of the natural vitamin.