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Objective Ultrasonography has been used to measure the cross-sectional area (CSA) of peripheral nerves, but the CSA of the brachial plexus has not previously been reported. The purpose of this study was to establish a reference range of values for the CSA of the brachial plexus, subclavian artery, and peak systolic velocity (PSV) of the subclavian artery in healthy subjects using ultrasonography. Methods Thirty-two asymptomatic subjects (19 men, 13 women) from a chiropractic college with an average age of 29.5 ± 9.6 participated in the study. The brachial plexus and subclavian artery CSA were measured at 3 locations: interscalene, first rib, and infraclavicular. The PSV of the subclavian artery was measured in both supraclavicular and infraclavicular locations. Each subject was imaged bilaterally. Means and 95% confidence intervals were calculated. Interexaminer reliability was evaluated between 2 examiners on 15 randomly selected subjects. Results The average CSA for the brachial plexus at the interscalene space, first rib, and infraclavicular location was 0.75 ± 0.05, 0.96 ± 0.07, and 0.98 ± 0.07 cm 2 , respectively. The average CSA for the subclavian artery at the same locations was 0.35 ± 0.03, 0.38 ± 0.03, 0.35 ± 0.03 cm 2 , respectively. The average subclavian artery PSV in supraclavicular and infraclavicular locations was 98 ± 8 and 93 ± 7 cm/s, respectively. The overall interexaminer reliability was poor at 0.39 (0.20-0.55). Conclusions This is the first study to obtain normative CSA measurements of the brachial plexus and subclavian artery in multiple locations of the thoracic outlet as well as interexaminer reliability data. These data may be beneficial in future studies designed to assess the brachial plexus and subclavian artery in patients with thoracic outlet syndrome.

Objective This study sought to use high-resolution ultrasound to measure changes in plantar fascia thickness as a result of tissue creep generated by walking and running. Methods Independent samples of participants were obtained. Thirty-six walkers and 25 runners walked on a treadmill for 10 minutes or ran for 30 minutes, respectively. Standardized measures of the thickness of the plantar fascia were obtained in both groups using high-resolution ultrasound. Results The mean thickness of the plantar fascia was measured immediately before and after participation. The mean plantar fascia thickness was decreased by 0.06 ± 0.33 mm SD after running and 0.03 ± 0.22 mm SD after walking. The difference between groups was not significant. Conclusion Although the parameters of this study did not produce significant changes in the plantar fascia thickness, a slightly higher change in the mean thickness of the plantar fascia in the running group deserves further investigation.

Background. To use sonography to measure the cross-sectional area (CSA) of the greater occipital nerve (GON) and the adjacent obliquus capi- tis inferior muscle (OCI) in normal subjects. Methods. Data from 30 asymptomatic subjects between the ages of 22 and 35 were collected. CSA and circumference of the GON and CSA of OCI were measured using sonography. Interexaminer reliability analysis was performed using the intraclass correla- tion coefficient. Results. The CSA of the GON and OCI were 2 mm 2 6 1m m 2 and 1.86 cm 2 6 0.51 cm 2 , respectively. The average circumference of the GON was 4.8 mm 6 1.3 mm. The interexaminer reliability of the measure- ments was excellent with intraclass correlation coeffi- cient coefficients of 0.91, 0.84, and 0.73 for the GON CSA, GON circumference, and OCI CSA, respectively. Conclusion. We report the normal values of the CSA of the GON and OCI. Knowledge of these normal values may facilitate the diagnosis of GON entrap- ment and provide outcome measures in therapeutic interventions. V

Noradrenergic function may be altered in depressive illness and thereby contribute to decreased pineal production of melatonin levels, as previously described in some depressed subjects. In the present study, the hypothesis was tested that pineal beta-adrenergic binding would be increased in persons committing suicide with evidence of depressive disorders, reflecting diminished noradrenergic input. Initially, post-mortem human pineal glands were obtained at autopsy. Diagnostic and symptomatic information was then systematically collected from family members using standardized interview techniques. Seven subjects who committed suicide and suffered from major depression, and without exposure to treatment for depressive symptoms were age- and sex-matched with control subjects. Pineal beta-adrenergic binding was assessed by quantitative autoradiography employing four concentrations of [125I]pindolol. Because of possibly complex adrenergic regulation of the pineal, beta-adrenergic receptor binding were subtyped using the selective blocker ICI 89406. No differences in beta-adrenergic receptors were detected between subjects with major depression compared to the matched controls.

Objective : This study tested the hypothesis that cocaine depletes dopamine levels in the brain. Method : Levels of dopamine, serotonin, and their metabolites in the frontal cortex and striatum of nine cocaine users and nine matched control subjects who had never used cocaine were determined from postmortem autopsy material. Results : The cocaine users had significantly lower dopamine levels and higher serotonin levels in the frontal cortex than the control subjects. Levels in other brain areas did not differ between the two groups. Conclusions: Alterations of dopamine and serotonin levels might contribute to symptoms of cocaine withdrawal and craving.

Animal studies suggest that chronic cocaine exposure may increase the function and/or synthesis of the dopamine transporter (DAT) under certain conditions, but the literature is complex. In order to test the hypothesis that cocaine exposure alters the DAT in humans, preliminary studies were done characterizing [3H]WIN 35428 binding in human striatum from normal controls. Following these experiments, the effects of chronic cocaine were examined in post mortem striatal specimens from 7 cocaine users and 7 controls matched for age and post mortem interval, employing quantitative autoradiography. Initial saturation experiments indicated that a one-site model was preferred with a Kd of 11 +/- 4 nM. [3H]WIN 35420 binding was then examined in cocaine users and controls at 0.5, 5, 10, and 50 nM radioligand concentrations. At each concentration of [3H]WIN 35420, optical densities for cocaine-exposed subjects were increased in caudate, putamen, and accumbens. The results suggest that total numbers of binding sites were increased in cocaine users. Based on the present and previous results, it appears that the regulation of the DAT is fairly plastic, and is highly sensitive to cocaine dosing regimes and withdrawal intervals. Chronic adaptations induced by cocaine in the DAT could contribute to the symptoms of binging, withdrawal depression, and/or craving.

Beta-adrenergic binding in frontal cortex samples from suicide victims has been reported to be increased, unaltered, and decreased compared to matched controls. Subject's diagnoses and drug exposures in these studies were not equivalently documented and were possibly different. In the present study, diagnostic and symptomatic information was systematically collected from family members of 15 subjects committing suicide and 15 matched controls using standardized interview techniques. The goal was to test the hypothesis that alterations in beta-adrenergic binding were more likely to be found in subjects with evidence of depressive disorders. [125I]pindolol binding in frontal cortex was found to be significantly lower in the group committing suicide compared to the matched controls (21.1 +/- 1.1 fmol/mg protein vs. 24.8 +/- 0.8 fmol/mg protein, p.02). However, no diagnostic subgroup among the suicide victims appeared distinct.

Amino acids have markedly different taste properties depending upon their chirality and the structure of their side chains. They can modify the taste quality of foods in which they are found naturally or to which they are added depending on their concentrations. In this study, the influence of chirality of amino acids on the growth in perceived taste intensity with concentration was examined. Serial dilutions of 19 D-amino acids were presented to young subjects who indicated the relative intensities of the dilutions using the magnitude estimation procedure. The slopes of the psychophysical functions for 13 of the 19 D-amino acids which related log concentration and log perceived intensity were greater than the slopes for L-amino acids that have been reported in a previous study. The ratio (average slope D-amino acids)/(average slope L-amino acids) was found to be 1.21. The ratio of the slopes for individual enantiomers bears some relationship to taste quality. No conclusive relationships between the slopes of the psychophysical functions were found with chemical structure or thresholds, however. Implications for receptor mechanisms and nutrition are discussed.

Serial dilutions of twenty-three amino acids were presented to young and elderly subjects who rated the relative intensities of the dilutions using the magnitude estimation procedure. In each case the slope of the psychophysical function relating concentration and perceived intensity was flatter for the elderly subjects: the mean ratio (slope (young)/slope (elderly)) was 2.55. This result could be due to an age-related decline in gustatory apparatus or associated central areas as well as memory loss and decline in performance often found in the elderly. No conclusive relationships between the slopes of the psychophysical functions were found with chemical structure, taste quality, or solubility.

Seventeen sweeteners varying widely in chemical structure were arranged in a three-dimensional space by two multidimensional scaling procedures, INDSCAL and ALSCAL. Fructose, glucose, sorbose, xylitol and xylose tended to fall near one another. Two sweeteners with a syrupy component, maltose and sorbitol, fell further away. Ca cyclamate and the dipeptide aspartame were the two artificial sweeteners which fell closest to and thus tasted most like the sugars. The proteins monellin and thaumatin, as well as the chalcone glycoside, neohesperidin dihydrochalcone, all have long aftertastes and thus tended to fall proximate to one another. Stimuli with the highest metallic and bitter ratings (acetosulfam, sodium saccharin, rebaudioside and stevioside) tended to fall near one another with the amino acid d-tryptophan located a little farther away. Adjective scales were related to the spatial arrangement. Wide variability in the patterns of intensity ratings over subjects suggests that the sweet taste may be mediated by several peripheral receptor mechanisms.

Taste detection thresholds for 11 sweeteners varying widely in chemical structure were determined for young and elderly subjects. The rank orders of the thresholds for young and elderly were highly correlated (Spearman's rho=0.976) although the thresholds were 2.72 times higher on the average for the elderly when compared with the young. This decreased sensitivity was statistically highly significant, p=0.000266. Sweeteners with the lowest detection thresholds tended to have the greatest number of units (AH-B systems) capable of intermolecular hydrogen bonding. In addition, use of the method of magnitude estimation with 10 sweeteners revealed that the elderly perceived less growth in intensity with increasing concentration than young subjects. The slopes of the psychophysical functions relating concentration and perceived intensity were flatter in all cases for elderly subjects; the mean ratio, slope(young)/slope(elderly), was 2.06. The largest relative decline in slope was found for those stimuli with the greatest number of possible AH-B types, suggesting that the possibilities for concerted intermolecular hydrogen bonding may decline with age. If the elderly compensate for their diminished taste acuity with increased consumption, they may constitute a population with higher than average risk of any adverse dose-related biological effects of artificial sweeteners.