Effect of cervical spinal adjustments on lumbar paraspinal muscle tone: evidence for facilitation of intersegmental tonic neck reflexes.

OBJECTIVES: To determine whether spinal adjustments, delivered to the upper vs. lower cervical spine, might result in tonic neck reflex-induced alterations in the activity of the lumbar paraspinal musculature. DESIGN: Randomized, double-blind, before/after treatment comparisons. SETTING: Cervical Ergonomics Laboratory, Palmer College of Chiropractic-West, Sunnyvale, CA. SUBJECTS: Healthy, nonsymptomatic chiropractic college students, about evenly divided with respect to gender and ranging from 23-38 yr of age. INTERVENTION: Modified "diversified" spinal adjustments, delivered bilaterally to either the upper (C2) or lower (C7) cervical region. MAIN OUTCOME MEASURE: Tissue compliance measures using a tissue compliance meter, obtained from each subject at sites 2 cm on either side of the spinous processes of L1, L2, L3, L4 and L5 both prior to and within 15 min following treatments. RESULTS: Upper cervical adjustments produced changes in lumbar tissue compliance which were only slight (p < .05) and not significantly different from that which occurred following upper cervical sham manipulation (p > .1). However, lower cervical adjustments induced increases in tissue compliance (decreases in tone) which were highly significant (p < .001) and relatively robust compared to those found following upper cervical adjustments (p < .01). Furthermore, the greatest effects were observed on either side of the L4 and L5 spinous processes, suggesting influences on the gluteal musculature in particular. CONCLUSIONS: Results indicate that cervical spinal manipulation can have significant effects on the tone of the lumbopelvic musculature, presumably by facilitating tonic neck reflexes involving intersegmental spinal pathways.

Comparisons between active vs. passive end-range assessments in subjects exhibiting cervical range of motion asymmetries.

OBJECTIVE: To compare cervical range of motion values following active (nonpractitioner-assisted) vs. passive (practitioner-assisted) movement of the head to end range. DESIGN: Randomized, double-blind, within-subject comparisons. SETTING: Cervical Ergonomics Laboratory, Palmer College of Chiropractic-West, Sunnyvale, CA. SUBJECTS: Pain-free chiropractic college students, nearly evenly divided with respect to gender and ranging from 22-38 yr of age, were used in the study. Subjects exhibiting goniometrically determined cervical lateral-flexion or rotational passive end-range asymmetries of 10 degrees or greater were selected for experimentation. INTERVENTION: None. MAIN OUTCOME MEASURE: A goniometric (inclinometric) device was used for active and passive cervical end-range assessments. Active assessments were performed first, followed immediately by passive assessments in each subject. RESULTS: Results demonstrated that the magnitudes of end-range asymmetry detected following active assessment were only about half of those observed following passive assessments. Moreover, whereas active end-range values were about 5 degrees less than passive on the most restricted side of passive movement, active end-range values were about 10 degrees less than passive on the least restricted side of passive end range. CONCLUSIONS: These results are consistent with the notion that cortical influences mediating active movement are rather intolerant of asymmetric states involving end-range capability. This results in compensatory reductions in active movement on the side of greatest potential passive end range, thereby acting to preserve symmetry at the expense of overall range of motion. Results also suggest that measures obtained following active movement may be far more difficult to interpret than those obtained following passive assessments, particularly when information regarding possible asymmetry of end-range capability is considered to be of primary clinical and/or experimental importance.

Effectiveness of upper versus lower cervical adjustments with respect to the amelioration of passive rotational versus lateral-flexion end-range asymmetries in otherwise asymptomatic subjects.

The effects of cervical spinal adjustments delivered bilaterally either to the upper cervical region (C2-C3) or to the lower cervical region (C6-C7), were compared in groups of asymptomatic subjects exhibiting goniometrically verified left-right rotational or left-right lateral-flexion passive end-range asymmetries of greater than 10 degrees. Goniometric evaluation both prior to, and again within 30 min following treatments revealed that lower cervical adjustments were far more effective for the amelioration of lateral-flexion asymmetries than were upper cervical ones, whereas upper cervical adjustments were found to be more effective for the amelioration of rotational asymmetries than those delivered to the lower cervical region. These results are consistent with the view that passive movement restriction exhibited along the rotational axis is attributable to factors related primarily to the upper cervical region, whereas restrictions of passive movement along the lateral axis are more attributable to factors related to the lower cervical region. Further support for the regional independence of these axis-specific relationships is provided by similar results obtained in groups of subjects who happened to exhibit both rotational as well as lateral-flexion asymmetries of greater than 10 degrees on the day of the experiment.

The comparative assessment of paraspinal tissue compliance in asymptomatic female and male subjects in both prone and standing positions.

Segmental bilateral paraspinal tissue compliance measures were obtained from 50 male and 50 female asymptomatic subjects (vertebral segments C7-L5). Interexaminer concordance for the taking of the measure was found to be extremely high (r greater than .90). Additionally, test-retest measures obtained from the same subjects initially, and again 15 min or 2 wk later indicated fairly low short-term as well as long-term temporal variabilities for the measure. The greatest levels of variability were encountered at lumbar segments, particularly with 2 wk intervals between assessments, and when measures were obtained with subjects in the standing, rather than prone, position. Data generated by this study suggest that tissue compliance assessments may provide useful information with respect to the contractile state of the paraspinal musculature at various regions or segmental levels.

Power spectral and microvector frequency analysis of dynamic standing foot force patterns in a normal male subject.

Power spectral and microvector frequency analyses of dynamic standing foot force patterns in a normal male subject were performed using a multiple-trial experimental protocol. Power spectral analysis of eight eyes-open vs. eyes-closed 50-sec trials revealed significant power increases in the 0.14 to 0.66 Hz range with eye closure, which were repeatable in trials performed on the same subject 2 wk later. Since power spectral differences are difficult to interpret biomechanically, a (micro)vector analysis of 1/20 sec changes in proportional weight transfer was employed. This methodology was able to reveal that foot force weight transfer exhibited a distinct preferred directionality, and that the eyes-closed condition was characterized by significant increases in both the occurrence and average magnitudes of these preferred microvectors.

Analysis of dynamic standing foot force patterns in a normal male subject by characterization of microvector weight transfer sequences.

Previous foot forceplate analyses in our laboratory have shown that postural sway in a normal male subject induces net weight transfers (microvectors) which have preferred directionalities, and that eye closure is characterized by increases in both the occurrence and magnitudes of these preferred microvectors. The same data generated from 8 x 8 blocks of eyes-open and eyes-closed trials were reanalyzed to examine microvector temporal sequences (i.e., macrovectors). Macrovectors were defined by the number of successive microvectors occurring along the same general direction, (anterior, posterior, right or left). Results suggest that with eye-closure, proprioceptive systems are unable to maintain lateral sway deviations within eyes-open limits. This instability increases lateral macrovector durations while only marginally affecting sagittal macrovector durations.

Normal paraspinal tissue compliance: the reliability of a new clinical and experimental instrument.

Test-retest reliability of a hand-held tissue compliance meter was evaluated in 20 normal subjects at four paraspinal locations to determine possible effects of probe response or other sources of variability on measurements taken 10 min later at exactly the same location. If tissue compliance, as measured by this instrument, is to be used in a pre-post context to evaluate treatment effects, caution is urged, since 26% of the sites were significantly (+/- 1.96 SD) different on 10 min retest though subjects remained supine and without intervention. In addition, since 85% of these normal subjects displayed at least one paraspinal compliance asymmetry large enough to qualify as pathological by Fischer's criteria, revision of these criteria may be appropriate, at least for these paraspinal locations.

Effect of unilateral spinal adjustments on goniometrically-assessed cervical lateral-flexion end-range asymmetries in otherwise asymptomatic subjects.

A triple blinded, multiple-measure, experimental protocol was employed in order to investigate the effectiveness of unilateral cervical adjustments on goniometrically assessed cervical lateral-flexion asymmetries. On pretest, subjects selected for the experiments exhibited mean left-right lateral-flexion differences of approximately 14 degrees. In subjects which either received no intervention, or had been subjected only to preliminary palpatory and set-up procedures but no thrust, asymmetry magnitudes were found to be unchanged on goniometric posttesting done 30-45 min later. However, in subjects which received lower cervical adjustments performed on the side of most restricted end-range, there was a dramatic reduction in asymmetry magnitudes. Furthermore, the adjustment procedure used in this investigation appeared to be relatively side-specific, since adjustments, when delivered to the less restricted side, were only marginally effective in ameliorating the asymmetries. Potential clinical relevance as well as the possible structural or physiological mechanisms responsible for the results obtained in the study are discussed.

Interexaminer concordance in detecting joint-play asymmetries in the cervical spines of otherwise asymptomatic subjects.

Interexaminer concordance for motion-based palpation of the middle and lower cervical spine was investigated. The palpatory task consisted of determining whether end-range joint resistance on lateral flexion was greater on one side of a given cervical segment when compared to that of the contralateral joint. Palpators also were asked to indicate the relative magnitude of the asymmetry, when detected. All experiments were carried out using reasonably healthy, pain-free, chiropractic college students. Three series of experiments involving two pairs of practitioners and a total of 270 subjects were carried out. Interexaminer agreement rates with respect to the side of greatest fixation were not found to be significantly different from those expected by chance alone. Furthermore, this was the case regardless of whether palpators had rated the magnitude of the asymmetry as being slight, moderate or severe. These poor agreement rates did not appear to be due to significant interexaminer differences with respect to the distributions of right vs. left calls, to a preponderance of agreements occurring more on one side over the other, or to differences with respect to the distribution of severity ratings. More importantly, there appeared to be no consistent relationships between the degree of severity indicated by the first examiner and that indicated by the second, nor were there any significant correlations between right vs. left agreement rates obtained for various combinations of severity ratings.(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnostic illusions: the reliability of random chance.

A "Monte Carlo" experiment was performed in order to determine chance concordance rates for multiple test scenarios often encountered in chiropractic diagnosis. The Monte Carlo simulation took into account the following variables: the number of tests involved in the diagnosis; the number of vertebral segments implicated by each test; the proportion of tests in agreement relative to the number of tests performed; and the segmental margin of error accepted. Random data for up to five diagnostic tests performed on 500 "patients" were computer generated and a wide variety of test scenarios analyzed. One typical analysis asked: if four diagnostic tests are performed on each patient, each test implicating on average three vertebral segments, and a plus or minus one segment error margin is accepted, what are the chance odds that any three out of the four tests will implicate the same vertebral segment? The answer, determined by simply counting how often this happened in the 500 "patients," was 89%. Many test scenarios yielded chance levels much higher than might have been expected. High probability situations as well as those test criteria yielding relatively low chance concordance rates are identified.

Concordance between galvanic skin response and spinal palpation findings in pain-free males.

The concordance between areas of paraspinal low resistance, i.e., galvanic skin response (GSR) and positive palpatory findings in pain-free male subjects was investigated. The concordance between vertebral segments implicated by GSR and by palpation was not found to be significantly different from chance concordance as determined by a t-test comparison of experimental results to randomly generated simulations, and by the application of Cohen's Kappa index of concordance to experimental data. This was true even when the locations of low resistance areas along the dorsal trunk were compared to only those vertebral palpatory findings rated as "severe." When test-retest reliability of GSR was examined, only 27% of vertebral segments implicated by GSR on initial examination were also implicated in the same subjects 4 h later. It was noted that low resistance areas detected by GSR were always punctate in nature and appeared to correspond well to known acupuncture loci. Further investigation revealed that, indeed, the GSR unit was not only effective in locating those acupuncture points that happened to be in a state of lowered resistance at the time but was also able, within about 5 sec, to decrease the resistance of any particular point not already in its lowest state of resistance to a level sufficient to generate a positive and persistent GSR reading where none had been detected previously. It is suggested that GSR may not be a reliable predictor of the location of vertebral pathology, at least as assessed by palpation in pain-free subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

A new clonal strain of rat pituitary tumour cells: a model for non-regulated secretion of prolactin.

A new clonal strain of Prl-secreting cells derived from the transplantable rat pituitary tumour, 7315a, has been established in culture. The cells of this strain, designed 235-1, have a highly developed Golgi complex, an extensive rough endoplasmic reticulum, and a few small but no large dense-core granules. When inoculated into athymic mice and rats of the Buffalo strain, the 235-1 cells produce tumours, and the host animals have hypertrophied mammary glands that produce milk, indicating that Prl secreted by these cells has mammotrophic activity. In monolayer culture, the doubling time of 235-1 cells is 31 +/- 1 h (mean +/- SE). The cells secrete Prl, a trace quantity of GH, but no LH, FSH, TSH, ACTH, or alpha-MSH. Prl is released at a rate of 257 +/- 12 fg per h per cell. The cellular content of Prl is 424 +/- 23 fg per cell. Prl secretion by 235-1 cells is not affected by dopaminergic agonists and antagonists, TRH, or oestradiol-17 beta but is inhibited in the presence of EGTA or monensin, an ionophore that is believed to act at the level of the Golgi complex. The subcellular distribution of Prl in 235-1 cells is different from that in rat pituitary cells. In 235-1 cells, Prl is associated not with a single set of dense particles as it is in pituitary cells but with 2 sets of subcellular particles, of which 1 set cosedimented with particles having lysosomal enzyme activity. These findings suggest that Prl secretion by 235-1 cells involves secretory pathways that are different from those seen in normal lactotrophs.

Estrogen alters the responsiveness of the anterior pituitary gland to the actions of dopamine on lysosomal enzyme activity and prolactin release.

The effects of dopamine on PRL secretion and lysosomal enzyme activity in anterior pituitary tissue from rats selected during various stages of the estrous cycle were examined under in vitro conditions. During the estrous cycle, there was a marked variation in the capacity of dopamine to stimulate the activity of the lysosomal enzyme beta-glucuronidase in the anterior pituitary gland. Moreover, this variation in the responsiveness of pituitary tissue to the stimulatory action of dopamine on beta-glucuronidase activity was accompanied by a similar variation in the responsiveness of the tissue to the inhibitory action of dopamine on PRL release. Anterior pituitary glands from diestrous rats were the most sensitive to the actions of dopamine on beta-glucuronidase activity and PRL release, whereas glands from estrous animals were the least sensitive. Ovariectomy on the day of diestrus prevented the decline in the responsiveness of the anterior lobe to the actions of dopamine normally seen 2 days later (on the presumptive day of estrus). On the other hand, when animals were treated with estradiol benzoate during the 2 days after ovariectomy, the responsiveness of the pituitary tissue to dopamine was markedly suppressed and was similar to that of tissue from estrous rats. When rats were treated with progesterone during the 2 days after ovariectomy, the responsiveness of the anterior lobe to dopamine was similar to that in ovariectomized controls. It is suggested that the decrease in the responsiveness of the anterior pituitary gland to the actions of dopamine on lysosomal enzyme activity and PRL release that occurs between diestrus and estrus is estrogen mediated. It is also suggested that the ability of estrogen to antagonize the inhibitory effect of dopamine on PRL release may be mediated through an estrogen-induced reduction in the capacity of dopamine to stimulate lysosomal enzyme activity in the anterior pituitary gland.

Role of estrogen in the dopaminergic control of prolactin secretion.

The effect of estrogen on the dopaminergic control of PRL secretion was investigated. Treatment of ovariectomized rats with estradiol benzoate (25 microgram/kg, sc) daily for 5 days resulted in a marked elevation of the serum PRL concentration. This estrogen-induced increase in serum PRL levels was apparently not the result of a suppressed release of dopamine into hypophysial portal blood, since the mean dopamine concentration in hypophysial portal plasma in estrogen-treated rats was 2.5 times that in vehicle-treated animals. It was found that under in vitro conditions, dopamine was much less effective in inhibiting the release of PRL from pituitary glands of estrogen-treated rats than from glands of vehicle-treated controls. The capacity of PRL cells to internalize dopamine and incorporate it into PRL secretory granules was evaluated in anterior pituitary tissue obtained from estrogen- or vehicle-treated animals. When tissue fragments of the anterior pituitary gland were incubated in the presence of dopamine (10(-5) M) for 30 min at 37 C and then homogenized and fractionated by means of continuous sucrose density gradient centrifugation, it was found that the amount of dopamine associated with PRL granules from anterior lobe tissue of estrogen-treated rats was only 40% of that from the tissue of vehicle-treated controls. These results are supportive of the hypothesis that the ability of estrogen to antagonize the inhibitory action of dopamine on PRL secretion is mediated through an estrogen-induced reduction in the capacity of the PRL cell to incorporate dopamine into PRL secretory granules. (Endocrinology 108: 440, 1981)

Neuroendocrine control of gonadotropin secretion.

Luteinizing hormone releasing hormone (LHRH), a hypothalmic peptide that is concentrated in granules of neurons, has the capacity to release gonadotropins (luteinizing hormone (LH) and follicle stimulating hormone) from the pituitary gland. LHRH has been found in hypophysial portal blood of rats, monkeys, and rabbits. Antibodies to LHRH depress plasma LH concentrations in castrated animals and evoke testicular atrophy, but passive immunization against LHRH does not block the LH surge induced by estrogen in monkeys. Estrogens, progestin, prolactin, and dopamine have marked effects on LH secretion, yet an association between these effects and altered hypophysial portal blood concentrations of LHRH is not established. In view of the paucity of evidence demonstrating such a cause and effect relationship, two alternative proposals have become tenable. One, hormones and neurotransmitters may not alter the levels of portal blood LHRH, but rather alter the frequency of pulsatile LHRH secretion. Two, hormones, such as estrogens, progesterone, and prolactin, may alter the responsiveness of the gonadotropin-secreting cells to LHRH by affecting the secretion of dopamine.

Subcellular localization of dopamine in the anterior pituitary gland of the rat: apparent association of dopamine with prolactin secretory granules.

The subcellular compartmentalization of endogenous dopamine in the anterior pituitary gland of the rat was investigated using continuous sucrose density gradient centrifugation. When anterior pituitary homogenates were layered on continuous sucrose density gradients (1.0--2.0 M) and centrifuged for 60 min at 40,000 X g, dopamine recovered from the gradients was associated with two sets of subcellular particles. The particles in one set were recovered near the top of the gradient, whereas those in the other set were recovered near the bottom of the gradient in the region where particles containing PRL were also found. In fact, these dense dopamine-containing particles could not be separated from those particles which contained PRL. These findings were suggestive that dopamine and PRL were present in the same particle, viz. the PRL secretory granule. This interpretation was further strengthened when it was established that the PRL-containing granules were separable on the gradient from granules which contained GH, LH, FSH, ACTH, and TSH. When [3H]dopamine was added to the solution in which the anterior lobes were homogenized, no radio-activity was found to be associated with the dense dopamine-containing particles. Also, the addition of a large excess of nonradiolabeled dopamine at the time of homogenization did not influence the amount of dopamine associated with the dense particles. Thus, the apparent association of dopamine with PRL secretory granules was not an artifact of the homogenization process per se. Therefore, it is concluded that an association exists between intracellular dopamine and the PRL secretory granule.