Everyday Impact of Cognitive Interventions in Mild Cognitive Impairment: a Systematic Review and Meta-Analysis

Cognitive interventions in Mild Cognitive Impairment (MCI) seek to ameliorate cognitive symptoms in the condition. Cognitive interventions may or may not generalize beyond cognitive outcomes to everyday life. This systematic review and meta-analysis sought to assess the effect of cognitive interventions compared to a control group in MCI on generalizability outcome measures [activities of daily living (ADLs), mood, quality of life (QOL), and metacognition] rather than cognitive outcomes alone. PRISMA guidelines were followed. MEDLINE and PsychInfo were utilized as data sources to locate references related to cognitive interventions in individuals with MCI. The cognitive intervention study was required to have a control or alternative treatment comparison group to be included. Thirty articles met criteria, including six computerized cognitive interventions, 14 therapist-based interventions, and 10 multimodal (i.e., cognitive intervention plus an additional intervention) studies. Small, but significant overall median effects were seen for ADLs (d = 0.23), mood (d = 0.16), and metacognitive outcomes (d = 0.30), but not for QOL (d = 0.10). Computerized studies appeared to benefit mood (depression, anxiety, and apathy) compared to controls, while therapist-based interventions and multimodal interventions had more impact on ADLs and metacognitive outcomes than control conditions. The results are encouraging that cognitive interventions in MCI may impact everyday life, but considerably more research is needed. The current review and meta-analysis is limited by our use of only PsychInfo and MEDLINE databases, our inability to read full text non-English articles, and our reliance on only published data to complete effect sizes.

A total score for the CERAD neuropsychological battery

OBJECTIVE

To develop a total or composite score for the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) neuropsychological battery.

METHOD

CERAD total scores were obtained by summing scores from the individual CERAD subtests (excluding the Mini-Mental State Examination [MMSE]) into a total composite (maximum score = 100). The method of tabulating the total score was constructed using normal controls (NCs; n = 424) and patients with AD (n = 835) from the CERAD registry database. The utility of the total score was further tested in independent samples of mild AD (n = 95), mild cognitive impairment (MCI; n = 60), and NC (n = 95) subjects.

RESULTS

The CERAD total score was highly accurate in differentiating NC and AD subjects in the CERAD registry. Age, gender, and education effects were observed, and demographic correction scores were derived through multiple regression analysis. Demographically corrected CERAD total scores showed excellent test-retest reliability across samples (r = 0.95) and were highly correlated with the MMSE (r = 0.89) and Clinical Dementia Rating Scale (r = -0.83) in mixed AD and NC samples and with the Blessed Dementia Rating Scale in an AD sample (r = -0.40). The CERAD total score was highly accurate in differentiating independent samples of NC, MCI, and AD subjects.

CONCLUSION

Results provide support for the validity of a Consortium to Establish a Registry for Alzheimer's Disease (CERAD) total score that can be used along with the normative data to provide an index of overall level of cognitive functioning from the CERAD neuropsychological battery.

Chemical activation of C(1)-C(2) spinal neurons modulates activity of thoracic respiratory interneurons in rats

Discharge patterns of thoracic dorsal horn neurons are influenced by chemical activation of cell bodies in cervical spinal segments C(1)-C(2). The present aim was to examine whether such activation would specifically affect thoracic respiratory interneurons (TRINs) of the deep dorsal horn and intermediate zone in pentobarbital sodium-anesthetized, paralyzed, artificially ventilated rats. We also characterized discharge patterns and pathways of TRIN activation in rats. A total of 77 cells were classified as TRINs by location, continued burst activity related to phrenic discharge when the respirator was stopped, and lack of antidromic response from selected pathways. A variety of respiration-phased discharge patterns was documented whose pathways were interrupted by ipsilateral C(1) transection. Glutamate pledgets (1 M, 1 min) on the dorsal surface of the spinal cord inhibited 22/49, excited 15/49, or excited/inhibited 3/49 tested cells. Incidence of responses did not depend on whether the phase of TRIN discharge was inspiratory, expiratory, or biphasic. Phrenic nerve activity was unaffected by chemical activation of C(1)-C(2) in this preparation. Besides supraspinal input, TRIN activity may be influenced by upper cervical modulatory pathways.

Therapy of metabolic disorders with intravenous (IV) access ports and long term intravenous L-carnitine therapy

With the expansion of newborn screening to include many organic acidurias and fatty acid oxidation defects, effective therapies of these disorders will be needed. Currently severe disorders such as methylmalonic and propionic aciduria. conventional therapy with diet and oral L-camitine often prove ineffective in preventing failure to thrive and recurrent metabolic decompensations. L-carnitine provides a natural pathway for removal of the toxic metabolites in these disorders and is life saving therapy but, with poor oral absorption (25%), it is difficult to supply adequate carnitine to meet the metabolic needs of these patients. Long term intravenous L-carnitine therapy, administered through a subcutaneous venous access port in 5 patients with organic acidurias [propionic aciduria (2), methylmalonic aciduria (2), 3 methylglutaconic aciduria(1)] resulted in improved growth, lower frequency of metabolic decompensations and increased tolerance of natural protein in the diet. An added benefit was the ability to initiate fluid. electrolytes, and antibiotics during metabolic decompensations at home thus averting hospitalizations.

Responses and afferent pathways of superficial and deeper c(1)-c(2) spinal cells to intrapericardial algogenic chemicals in rats

Electrical stimulation of vagal afferents or cardiopulmonary sympathetic afferent fibers excites C(1)--C(2) spinal neurons. The purposes of this study were to compare the responses of superficial (depth <0.35 mm) and deeper C(1)--C(2) spinal neurons to noxious chemical stimulation of cardiac afferents and determine the relative contribution of vagal and sympathetic afferent pathways for transmission of noxious cardiac afferent input to C(1)--C(2) neurons. Extracellular potentials of single C(1)--C(2) neurons were recorded in pentobarbital anesthetized and paralyzed male rats. A catheter was placed in the pericardial sac to administer a mixture of algogenic chemicals (0.2 ml) that contained adenosine (10(-3) M), bradykinin, histamine, serotonin, and prostaglandin E(2) (10(-5) M each). Intrapericardial chemicals changed the activity of 20/106 (19%) C(1)--C(2) spinal neurons in the superficial laminae, whereas 76/147 (52%) deeper neurons responded to cardiac noxious input (P < 0.01). Of 96 neurons responsive to cardiac inputs, 48 (50%) were excited (E), 41 (43%) were inhibited (I), and 7 were excited/inhibited (E-I) by intrapericardial chemicals. E or I neurons responsive to intrapericardial chemicals were subdivided into two groups: short-lasting (SL) and long-lasting (LL) response patterns. In superficial gray matter, excitatory responses to cardiac inputs were more likely to be LL-E than SL-E neurons. Mechanical stimulation of the somatic field from the head, neck, and shoulder areas excited 85 of 95 (89%) C(1)--C(2) spinal neurons that responded to intrapericardial chemicals; 31 neurons were classified as wide dynamic range, 49 were high threshold, 5 responded only to joint movement, and no neuron was classified as low threshold. For superficial neurons, 53% had small somatic fields and 21% had bilateral fields. In contrast, 31% of the deeper neurons had small somatic fields and 46% had bilateral fields. Ipsilateral cervical vagotomy interrupted cardiac noxious input to 8/30 (6 E, 2 I) neurons; sequential transection of the contralateral cervical vagus nerve (bilateral vagotomy) eliminated the responses to intrapericardial chemicals in 4/22 (3 E, 1 I) neurons. Spinal transection at C(6)--C(7) segments to interrupt effects of sympathetic afferent input abolished responses to cardiac input in 10/10 (7 E, 3 I) neurons that still responded after bilateral vagotomy. Results of this study support the concept that C(1)-C(2) superficial and deeper spinal neurons play a role in integrating cardiac noxious inputs that travel in both the cervical vagal and/or thoracic sympathetic afferent nerves.

Low intensity spinal cord stimulation may induce cutaneous vasodilation via CGRP release

This study examined whether spinal cord stimulation (SCS) at intensities below motor threshold (MT) produces cutaneous vasodilation through sympathetic inhibition and/or antidromic activation of sensory fibers. SCS was applied to anesthetized rats with stimulus parameters used clinically, i.e. 50 Hz, 0.2 ms and stimulus intensities at 30, 60 or 90% of MT. SCS-induced vasodilation was not attenuated by hexamethonium, an autonomic ganglion blocking agent, but was abolished by CGRP-(8-37), an antagonist of the calcitonin gene-related peptide (CGRP) receptor. We concluded that SCS-induced vasodilation under the conditions of this study was mediated by peripheral release of CGRP via antidromic activation of sensory fibers.

Intrapericardiac injections of algogenic chemicals excite primate C1-C2 spinothalamic tract neurons

Extracellular potentials of 38 C1-C2 spinothalamic tract (STT) neurons in anesthetized monkeys (Macaca fascicularis) were examined for responses to intrapericardiac injections of an algogenic chemical mixture (adenosine, 10(-3) M; bradykinin, prostaglandin E(2), serotonin, histamine, each 10(-5) M). Chemical stimulation of cardiac/pericardiac receptors increased activity of 21 cells, decreased activity of 5 cells, and did not change activity of 12 cells. Cells excited by chemical stimuli received input from noxious mechanical stimulation of somatic fields; most receptive fields included the neck, inferior jaw, or head areas. Nerve ablations in 11 cells excited by intrapericardiac chemicals showed that cardiac input activated by algogenic chemicals traveled primarily in vagal afferent fibers to C1-C2 segments; phrenic or cardiopulmonary sympathetic inputs were predominant in 2 of 11 cells. These results supported the concept that activation of cardiac vagal afferents might lead to the production of referred pain sensation in somatic fields innervated from high cervical segments.

Modulation of intrinsic cardiac neurons by spinal cord stimulation: implications for its therapeutic use in angina pectoris

OBJECTIVE

Electrical stimulation of the dorsal aspect of the upper thoracic spinal cord is used increasingly to treat patients with severe angina pectoris refractory to conventional therapeutic strategies. Clinical studies show that spinal cord stimulation (SCS) is a safe adjunct therapy for cardiac patients, producing anti-anginal as well as anti-ischemic effects. However, little information is yet available about the underlying mechanisms involved.

METHODS

In order to determine its mechanism of action, the effects of SCS on the final common integrator of cardiac function, the intrinsic cardiac nervous system, was studied during basal states as well as during transient (2 min) myocardial ischemia. Activity generated by intrinsic cardiac neurons was recorded in 9 anesthetized dogs in the absence and presence of myocardial ischemia before, during and after stimulating the dorsal T1-T2 segments of the spinal cord at 66 and 90% of motor threshold using epidural bipolar electrodes (50 Hz; 0.2 ms; parameters within the therapeutic range used in humans).

RESULTS

The SCS suppressed activity generated by intrinsic cardiac neurons. No concomitant change in monitored cardiovascular indices was detected. Neuronal activity increased during transient ventricular ischemia (46%), as well as during the early reperfusion period (68% compared to control). Despite that, activity was suppressed during both states by SCS.

CONCLUSIONS

SCS modifies the capacity of intrinsic cardiac neurons to generate activity. SCS also acts to suppress the excitatory effects that local myocardial ischemia exerts on such neurons. Since no significant changes in monitored cardiovascular indices were observed during SCS, it is concluded that modulation of the intrinsic cardiac nervous system might contribute to the therapeutic effects of SCS in patients with angina pectoris.

Effects of abdominal or cardiopulmonary sympathetic afferents on upper cervical inspiratory neurons

Responses of upper cervical inspiratory neurons (UCINs) to abdominal visceral or cardiopulmonary sympathetic stimulation were studied using extracellular recordings from 213 UCINs in 54 pentobarbital sodium-anesthetized and paralyzed rats. Phrenic nerve activity was used to assess inspiration. The UCINs discharging during inspiration only were mainly in the C(1) segment, whereas phase-spanning UCINs were mostly in the C(2) segment. Phase-spanning activity was typically retained after overventilation or vagotomy. When greater splanchnic nerve (GSN) or cardiopulmonary sympathetic afferent (CPSA) fibers were electrically stimulated, augmented UCIN activity was observed in 65% of cells responding to CPSA stimulation but in only 17% of cells responding to GSN. Response latencies were 10.7 +/- 0.5 and 20.6 +/- 1.5 (SE) ms, respectively. Many augmented responses to CPSA stimulation (64%) and all augmented responses to GSN stimulation were followed by suppression of UCIN discharge (biphasic response). Phrenic nerve activity was suppressed by both GSN and CPSA stimulation, but with shorter latency for the latter (29 +/- 0.7 vs. 14.0 +/- 0.7 ms). Excitation of UCINs using CPSA stimulation occurs more often and by a more direct pathway than for GSN input.

Beliefs about truth and beliefs about rightness

Children's developing conceptions of what is right or proper are commonly studied without reference to concomitant changes in their understanding of beliefs, just as studies of young people's maturing grasp of the belief entitlement process ordinarily proceed separately from any examination of the value considerations that invest beliefs with meaning. In an effort to reverse these isolationist practices, a case is made for rereading the fact-value dichotomy that currently works to divide the contemporaneous literatures dealing with children's moral reasoning development and their evolving theories of mind. Findings from two research programs, in which children's beliefs about truth and rightness are combined, serve to illustrate the natural interdependence of these moral and epistemic matters.

Chemical activation of cervical cell bodies: effects on responses to colorectal distension in lumbosacral spinal cord of rats

We have shown that stimulation of cardiopulmonary sympathetic afferent fibers activates relays in upper cervical segments to suppress activity of lumbosacral spinal cells. The purpose of this study was to determine if chemical excitation (glutamate) of upper cervical cell bodies changes the spontaneous activity and evoked responses of lumbosacral spinal cells to colorectal distension (CRD). Extracellular potentials were recorded in pentobarbital-anesthetized male rats. CRD (80 mmHg) was produced by inflating a balloon inserted in the descending colon and rectum. A total of 135 cells in the lumbosacral segments (L(6)-S(2)) were activated by CRD. Seventy-five percent (95/126) of tested cells received convergent somatic input from the scrotum, perianal region, hindlimb, and tail; 99/135 (73%) cells were excited or excited/inhibited by CRD; and 36 (27%) cells were inhibited or inhibited/excited by CRD. A glutamate (1 M) pledget placed on the surface of C(1)-C(2) segments decreased spontaneous activity and excitatory CRD responses of 33/56 cells and increased spontaneous activity of 13/19 cells inhibited by CRD. Glutamate applied to C(6)-C(7) segments decreased activity of 10/18 cells excited by CRD, and 9 of these also were inhibited by glutamate at C(1)-C(2) segments. Glutamate at C(6)-C(7) increased activity of 4/6 cells inhibited by CRD and excited by glutamate at C(1)-C(2) segments. After transection at rostral C(1) segment, glutamate at C(1)-C(2) still reduced excitatory responses of 7/10 cells. Further, inhibitory effects of C(6)-C(7) glutamate on excitatory responses to CRD still occurred after rostral C(1) transection but were abolished after a rostral C(6) transection in 4/4 cells. These data showed that C(1)-C(2) cells activated with glutamate primarily produced inhibition of evoked responses to visceral stimulation of lumbosacral spinal cells. Inhibition resulting from activation of cells in C(6)-C(7) segments required connections in the upper cervical segments. These results provide evidence that upper cervical cells integrate information that modulates activity of distant spinal neurons responding to visceral input.

Convergence of trigeminal input with visceral and phrenic inputs on primate C1-C2 spinothalamic tract neurons

Trigeminal, spinal and vagal afferent fibers overlap in C1-C2 segments. We hypothesized that trigeminal input from the superior sagittal sinus (SSS) can excite C1-C2 spinothalamic tract (STT) neurons receiving thoracic visceral or phrenic inputs. Effects of SSS stimulation were evenly divided among cells responding to each nerve stimulus; magnitude of responses to ipsilateral vagal input was greater in neurons excited by SSS input. Somatic fields of 80% of neurons responding to SSS stimulation included face areas innervated by the trigeminal nerve, whereas somatic fields of 89% of neurons unaffected by SSS stimulation were located only on areas innervated by cervical spinal nerves. Results are consistent with the idea that pain referred to trigeminal areas could originate in thoracic organs.

Spinal integration of antidromic mediated cutaneous vasodilation during dorsal spinal cord stimulation in the rat

The purpose of this study was to determine the involvement of supraspinal centers and spinal synaptic integration in cutaneous vasodilation mediated by dorsal spinal cord stimulation (DCS). Laser Doppler flowmetry was used to assess cutaneous blood flow changes in the rat hindpaw during DCS with a unipolar ball electrode placed at the L2-L3 spinal level. Results demonstrated that transecting the spinal cord at the T10 spinal segment did not alter the DCS response while T13 spinal transection abolished the DCS-induced vasodilation. Inhibition of synaptic activity with topical application of muscimol (0.2 mM) on the dorsal surface of the spinal cord markedly attenuated the DCS response. In conclusion DCS-induced vasodilation involved synaptic integration but did not require input from rostral spinal sites or supraspinal areas.

Propriospinal neurons in the C1-C2 spinal segments project to the L5-S1 segments of the rat spinal cord

Physiological studies indicate that neurons in the upper cervical spinal cord have descending projections to the lumbosacral spinal cord and mediate inhibition of dorsal horn neurons activated from afferent input. In the present study, retrograde tracing techniques were used to examine the distribution of propriospinal neurons in C1-C2 spinal segments that project to lumbosacral spinal segments. Fluorogold or horseradish peroxidase were injected unilaterally or bilaterally into the L5-S1 spinal segments. After 2-4 days, rats were perfused with fixative and C1-C2 spinal segments were processed for retrograde labeling. Numerous neurons were found in the C1-C2 segments. In unilaterally and bilaterally injected rats, retrogradely labeled neurons were located on both the ipsilateral and contralateral sides. Retrogradely labeled neurons were located in the following locations: lateral cervical and spinal nuclei, nucleus proprius, ventral horn and the central gray region (area X). These studies demonstrate a descending projection from C1-C2 segments to the lower lumbar and sacral spinal cord. We hypothesize that many of these C1-C2 propriospinal neurons are important in modulating responses of spinal neurons at lower segmental levels to various peripheral stimuli.

Cardiopulmonary sympathetic input excites primate cuneothalamic neurons: comparison with spinothalamic tract neurons

Stimulation of cardiopulmonary sympathetic afferent fibers excites thoracic and cervical spinothalamic tract (STT) cells that respond primarily to noxious somatic stimuli. Neurons in dorsal column nuclei respond primarily to innocuous somatic inputs, but noxious stimulation of pelvic viscera activates gracile neurons. The purpose of this study was to compare effects of thoracic visceral input on cuneothalamic and STT neurons. Stellate ganglia of 17 anesthetized monkeys (Macaca fascicularis) were stimulated electrically to activate cardiopulmonary sympathetic afferent fibers. Somatic receptive fields were manipulated with brush, tap, and pinch stimuli. Extracellular discharge rate was recorded for neurons antidromically activated from ventroposterolateral (VPL) thalamus. Stimulation of the ipsilateral stellate ganglion increased activity of 17 of 38 cuneothalamic neurons and of 1 gracilothalamic neuron with an upper body somatic field. Spinal cord transections showed that cardiopulmonary input to cuneothalamic neurons traveled in ipsilateral dorsal column and probably in dorsolateral funiculus. One of eight gracilothalamic neurons with lower body fields was inhibited by cardiopulmonary input, and none were excited. Stimulation of the ipsilateral stellate ganglion increased activity in 10 of 10 T3-T4 STT neurons. Evoked discharge rates, latencies to activation and durations of peristimulus histogram peaks were significantly less for cuneothalamic neurons compared with STT neurons. Furthermore, additional long latency peaks of activity developed in histograms for 6 of 10 STT neurons but never for cuneothalamic neurons. Contralateral cardiopulmonary sympathetic input did not excite cuneothalamic neurons but increased activity of 7 of 10 T3-T4 STT neurons. Most cuneothalamic neurons (24 of 31 cells tested) responded primarily to innocuous somatic stimuli, whereas STT neurons responded primarily or solely to noxious pinch of somatic fields. Neurons that responded to cardiopulmonary input most often had somatic fields located on proximal arm and chest. Results of this study showed that cardiopulmonary input was transmitted in dorsal pathways to cuneate nucleus and then to VPL thalamus and confirmed that STT neurons transmit nociceptive cardiopulmonary input to VPL thalamus. Differences in neuronal responses to noxious stimulation of cardiopulmonary sympathetic afferent fibers suggest that dorsal and ventrolateral pathways to VPL thalamus play different roles in the transmission and integration of nociceptive cardiac information.

Phrenic nerve inputs to upper cervical (C1-C3) spinothalamic tract neurons in monkeys

Afferent input from the phrenic nerve enters mid-cervical spinal segments, and previous results in monkeys show that mid-cervical spinothalamic (STT) neurons are activated by groups II and III phrenic afferent input arising from the diaphragm. In rats, dorsal horn neurons in C1-C2 segments receive phrenic input stimulated above the heart, but are not activated by phrenic input arising from diaphragm or abdomen. It is not known if this differential organization occurs in primate STT neurons. We hypothesized that high cervical STT neurons in monkeys also would be preferentially activated by phrenic inputs from thoracic structures, such as the pericardium. We examined extracellular discharge rate of C1-C3 STT neurons for responses to electrical stimulation of phrenic nerve fibers. Responses to stimulation of ipsilateral phrenic fibers above the heart were compared to effects of input stimulated below the heart and also to effects of contralateral phrenic input. We concluded that upper cervical STT neurons are most strongly excited by ipsilateral input from small diameter phrenic fibers arising from thoracic structures, but that group III and IV input from diaphragmatic fibers as well as input from contralateral phrenic fibers have a lesser effect on C1-C3 STT neurons and thus might be involved in nociceptive processing.

Cardiopulmonary sympathetic afferent input does not require dorsal column pathways to excite C1-C3 spinal cells in rats

Effects of electrically stimulating the left stellate ganglion to activate cardiopulmonary sympathetic afferent (CPSA) fibers were determined on C1-C3 dorsal horn neurons in anaesthetized rats. Fifty-two of 53 dorsal horn neurons affected by CPSA stimulation were excited and one neuron was inhibited. In 6 experiments, dorsal columns and ventrolateral funiculi were sequentially lesioned to determine neuronal pathways involved in CPSA activation of C1-C3 neurons. In 6 additional experiments, spinal transection at rostral C1 was used to determine the contribution of supraspinal relays. We concluded that CPSA input to C1-C3 segments travelled bilaterally in ventrolateral pathways, and that supraspinal relays were not required for CPSA excitation of C1-C3 neurons. These results suggest that neurons in C1-C3 segments might play an important role in processing visceral spinal afferent information.

Role of nitric oxide in cutaneous blood flow increases in the rat hindpaw during dorsal column stimulation

OBJECTIVE

Dorsal column stimulation (DCS) increases blood flow to the extremities and may produce a limb-saving effect in addition to treatment of refractory chronic pain in patients with peripheral vascular disease. The purpose of this study was to examine the importance of nitric oxide in cutaneous vasodilation caused by DCS.

METHODS

Male Sprague-Dawley rats were anesthetized with pentobarbital (60 mg/kg, intraperitoneally). A unipolar ball electrode was placed on the left-side of the exposed spinal cord at approximately L1-L2. Blood flow was concurrently recorded from both hindpaw foot pads with laser doppler flowmeters. Blood flow responses were assessed during 1 minute of DCS (0.6 mA at 50 Hz, 0.2-ms pulse) at 10-minute intervals. Nitric oxide synthase was inhibited with NG-nitro-L-arginine methyl ester (L-NAME). Four groups of animals were examined. The first and second groups involved examination of the effects of DCS after 2 and 10 mg/kg L-NAME, respectively. In the third group, the effect of another nitric oxide synthase inhibitor, NG-monomethyl-L-arginine (10 mg/kg), was examined on the responses to DCS. The fourth group of animals entailed comparison of the effects of DCS under control conditions, after the nicotinic receptor antagonist, hexamethonium (10 mg/kg), and during the combined presence of hexamethonium and L-NAME (10 mg/kg).

RESULTS

L-NAME markedly attenuated the cutaneous blood flow increases caused by DCS at doses of 2 or 10 mg/kg. Similarly, NG-monomethyl-L-arginine also attenuated the DCS response. Hexamethonium did not affect the cutaneous vasodilation caused by DCS. After hexamethonium, L-NAME no longer attenuated the DCS response.

CONCLUSION

Our results demonstrated that nitric oxide played a significant role in producing the DCS-induced increase in rat cutaneous hindpaw blood flow. The involvement of nitric oxide does not require the presence of autonomic efferent function; however, ganglionic blockade may unmask a mechanism for vasodilation during DCS that is independent of nitric oxide release.

Cutaneous vasodilation during dorsal column stimulation is mediated by dorsal roots and CGRP

Dorsal column stimulation (DCS) is used clinically to provide pain relief from peripheral vascular disease and has the benefit of increasing cutaneous blood flow to the affected lower extremities. The purpose of this study was to examine the role of dorsal roots, calcitonin gene-related peptide (CGRP), and substance P in the cutaneous vasodilation induced by DCS. Male rats were anesthetized with pentobarbital sodium (60 mg/kg ip). A unipolar ball electrode was placed unilaterally on the spinal cord at the L1-L2 spinal segment. Blood flow was recorded in each hindpaw foot pad with laser Doppler flowmeters. Blood flow responses were assessed during 1 min of DCS (either 0.2 mA subdural or 0.6 mA epidural at 50 Hz, 0.2-ms pulse duration). Dorsal rhizotomy of L3-L5 (n = 5) abolished the cutaneous vasodilation to subdural DCS, whereas removal of T10-T12 (n = 5) and T13-L2 dorsal roots (n = 5) did not attenuate the DCS-induced vasodilation. The CGRP antagonist, CGRP-(8-37) (2.6 mg/kg iv, n = 7), eliminated the epidural DCS-induced vasodilation, whereas the substance P receptor antagonist, CP-96345 (1 mg/kg iv, n = 6), had no effect. In summary, L3-L5 dorsal roots and CGRP are essential for the DCS-induced vasodilation. We propose that DCS antidromically activates afferent fibers in the dorsal roots, thus causing peripheral release of CGRP, which produces cutaneous vasodilation.

Vagal, sympathetic and somatic sensory inputs to upper cervical (C1-C3) spinothalamic tract neurons in monkeys

1. Myocardial ischemia activates vagal and sympathetic cardiac afferent fibers. The purpose of this study was to determine a neuro physiological basis for cardiac pain referred to C1-C3 somatic dermatomes. We hypothesized that afferent fibers traveling in vagal or sympathetic nerves transmit nociceptive information to C1-C3 spinothalamic tract (STT) neurons. 2. Electrical stimulation of the left stellate ganglion to excite cardiopulmonary sympathetic afferent fibers increased extracellular activity of 44 of 77 C1-C3 STT neurons examined in 33 anesthetized male monkeys (Macaca fascicularis); responses increased as stimulus strength increased. Additionally, this stimulus inhibited 5 cells, increased/decreased activity of 2 cells, and did not affect 26 cells. 3. Electrical stimulation of the left (ipsilateral) thoracic vagus nerve excited 41 of 78 C1-C3 STT neurons, inhibited 4 neurons, increased/decreased activity of 2 neurons, and did not affect 31 neurons. Responses increased with increasing stimulus strength Contralateral vagal stimulation excited 7 of 39 cells tested, inhibited 4 cells and did not affect 28 cells. 4. Effects of stimulating one or more vagal branches were examined on 22 C1-C3 STT neurons excited by input from left thoracic vagus nerve. Stimulation of the cardiac branch excited 11 of 16 cells tested; stimulation of the recurrent laryngeal nerve excited 11 of 18 cells; stimulation of vagal fibers just rostral to the diaphragm excited 8 of 19 cells. 5. Excitatory somatic receptive fields ranged from small ipsilateral fields to large, sometimes bilateral or noncontinuous fields. Many fields included the ipsilateral neck and/or inferior jaw. Thirty-nine of 74 neurons examined were wide dynamic range (WDR), 21 were high threshold (HT), 6 were low threshold (LT), and 8 did not respond to brushing or noxious pinching of somatic tissues. Most (38 of 39) WDR cells responded to stimulation of the stellate ganglion or vagal fibers, as did 18 of 21 HT cells, 3 of 6 LT cells, and 2 of 8 cells unresponsive to brush or pinch stimuli. 6. Results of this study supported the concept that vagal and/ or sympathetic afferent activation of C1-C3 STT neurons might provide a neural mechanism for referred pain that originates in the heart or other visceral organs but is perceived in the neck and jaw region. Additionally, C1-C3 STT neurons processed sensory information from widespread regions of the body.

Cutaneous blood flow increases in the rat hindpaw during dorsal column stimulation

The purpose of this study was to determine the optimal stimulation site and parameters that result in the greatest changes in cutaneous blood flow during dorsal column stimulation (DCS). Laser Doppler flowmetry was used to assess cutaneous blood flow changes in both rat hindpaws during DCS with a unipolar ball electrode. We found that stimulating the dorsal column at the L2 spinal segment at 0.6 mA at either 25 or 50 Hz with a pulse duration of 0.2 ms resulted in the largest cutaneous blood flow increases in the rat hindpaw. In addition, the DCS response appeared to be limited primarily to the hindpaw ipsilateral to the site of DCS.

Thoracic visceral inputs use upper cervical segments to inhibit lumbar spinal neurons in rats

We tested the hypothesis that cardiopulmonary sympathetic afferent (CPSA) input entering upper thoracic spinal segments relays in the cervical spinal cord to inhibit activity of lumbar spinothalamic tract (SST) cells and dorsal horn (DH) cells. Two sequential spinal transections in the same animal were made, one at rostral C1 and one at C4-C6 segments, to determine neuronal pathways involved in the inhibition. We concluded that inhibitory effects induced by CPSA and somatic stimulation might be mediated by propriospinal mechanisms located in upper cervical segments. Vagal inhibition required supraspinal pathways.

Responses of feline raphespinal neurons to urinary bladder distension

Effects of distending the urinary bladder were studied on extracellular activity of 77 raphespinal neurons in 19 alpha-chloralose anesthetized cats. Neurons were activated antidromically from thoracic spinal cord; recording sites were located in nucleus raphe magnus (NRM). Mean conduction velocity was 48 +/- 2 m/s. Urinary bladder distension (UBD) increased activity in 12 cells and decreased activity in 17 cells. Spontaneous bladder contractions also affected activity in raphespinal neurons responsive to UBD. Noxious pinch stimulus applied to proximal hindlimbs or forelimbs either increased or decreased activity in 28 raphespinal neurons. No cells were excited both by UBD and pinching of skin and deep tissues of the limbs. Thus, excitatory viscerosomatic convergence was not observed with the stimuli tested in raphespinal neurons examined in this study. Urinary bladder input to descending projection neurons in NRM might participate in descending modulation of dorsal horn neurons. In addition, micturition reflexes might be affected by urinary bladder input to these neurons.

A mechanism of cardiac pain suppression by spinal cord stimulation: implications for patients with angina pectoris

Clinical reports show that electrical stimulation of the spinal cord reduces symptoms of angina pectoris, but so far have not provided evidence on the mechanisms involved. The hypothesis for this study was that inhibition of spinothalamic tract transmission may account for this result. Extracellular potentials of 28 spinothalamic tract neurons were recorded in anaesthetized monkeys, and the effects of dorsal column stimulation were determined on activity evoked by cardiac and somatic stimuli. Dorsal column stimulation reduced the number of cell potentials evoked by electrical stimulation of cardiopulmonary sympathetic afferent fibres in 11 spinothalamic tract cells tested. Activity evoked by intracardiac injection of bradykinin was decreased by dorsal column stimulation in six of seven neurons that responded to chemical stimulation of afferents. Differential effects of dorsal column stimulation were correlated to the cell responses to somatic field stimulation. Dorsal column stimulation inhibited activity in 12 of 12 neurons which were excited only by noxious pinch of somatic fields, whereas eight of 16 neurons which were excited by innocuous brushing of somatic fields were unaffected or excited. Transection of the dorsal column showed that the pathway transmitting inhibitory impulses descended from the stimulation site to the spinothalamic tract neurons examined. Results of this study are consistent with the concept that spinal cord stimulation reduces pain by decreasing the firing of spinothalamic tract cells which are activated by small fibre afferents. The paresthesias associated with nerve stimulation techniques may result from activation of spinothalamic tract cells which are excited by large fibre afferents. The clinical decision to employ spinal cord stimulation in patients with angina should balance the obvious benefit of pain relief against the risk of depriving the patient of an important warning signal while active myocardial ischaemia is in progress.

Segmental organization of visceral and somatic input onto C3-T6 spinothalamic tract cells of the monkey

1. Referred pain of visceral origin has three major characteristics: visceral pain is referred to somatic areas that are innervated from the same spinal segments as the diseased organ; visceral pain is referred to proximal body regions and not to distal body areas; and visceral pain is felt as deep pain and not as cutaneous pain. The neurophysiological basis for these phenomena is poorly understood. The purpose of this study was to examine the organization of viscerosomatic response characteristics of spinothalamic tract (STT) neurons in the rostral spinal cord. Interactions were determined among the following: 1) segmental location, 2) effects of input by cardiopulmonary sympathetic, greater splanchnic, lumbar sympathetic, and urinary bladder afferent fibers, 3) location of excitatory somatic field, e.g., hand, forearm, proximal arm, or chest, 4) magnitude of response to hair, skin, and deep mechanoreceptor afferent input, and 5) regional specificity of thalamic projection sites. 2. A total of 89 STT neurons in segments C3-T6 were characterized for responses to visceral and somatic stimuli. Neurons were activated antidromically from the contralateral ventroposterolateral oralis or caudalis nuclei of the thalamus. Cell responses to visceral and somatic stimuli were not different on the basis of the thalamic site of antidromic activation. Recording sites for 61 neurons were located histologically; 87% of lesion sites were located in laminae IV-VII or X. There was no relationship between response properties of the neurons and spinal laminar location. 3. Different responses to visceral stimuli were observed in three zones of the rostral spinal cord: C3-C6, C7-C8, and T1-T6. In C3-C6, urinary bladder distension (UBD) and electrical stimulation of greater splanchnic and lumbar sympathetic afferent fibers inhibited STT cells. Electrical stimulation of cardiopulmonary sympathetic afferents increased cell activity in C5 and C6 and either excited or inhibited STT cells in C3 and C4. In the cervical enlargement (C7-C8), STT cells generally were either inhibited or showed little response to stimulation of visceral afferent fibers. In T1-T6, input from greater splanchnic and cardiopulmonary sympathetic afferent nerves increased activity of STT cells. Lumbar sympathetic afferent input inhibited cells in T1-T2 and had little effect on cells in T3-T6, whereas UBD decreased cell activity in all segments studied. 4. In general, stimulation of somatic structures increased activity of STT neurons in segments that received primary afferent innervation from the excitatory somatic receptive field or in the segments immediately adjacent to these segments. Only input from the forelimb, especially the hand, markedly excited cells in C7 and C8.+

Intracardiac phenylbiguanide causes excitation of spinal neurons by activation of cardiac sympathetic afferents

The responses of spinothalamic, spinoreticular, and unidentified spinal neurons to intracardiac administration of phenylbiguanide, a 5-HT3 receptor agonist, were examined in anesthetized cats and monkeys. Eighteen neurons were excited, 5 were inhibited, and 12 were unresponsive to this stimulus. Results suggest that cardiac sympathetic afferents mediate the excitatory responses produced by phenylbiguanide, because bilateral cervical vagotomy failed to block these responses, and aortic injections of phenylbiguanide had little effect on cell activity.

Evidence that C1 and C2 propriospinal neurons mediate the inhibitory effects of viscerosomatic spinal afferent input on primate spinothalamic tract neurons

1. Lumbosacral spinothalamic tract (STT) neurons can be inhibited by noxious pinch of the contralateral hindlimb or either forelimb and by electrical stimulation of cardiopulmonary sympathetic, splanchnic, and hypogastric afferents. A previous study found that spinal transections between C2 and C4 sometimes abolished the inhibitory effect of spinal afferent input and sometimes left it intact. This suggested that propriospinal neurons in the C1 and C2 segments might mediate this effect. To test whether neurons in the C1 and C2 segments were involved in producing this inhibitory effect, the magnitude of the reduction in neural activity was measured in the same STT neuron before and after spinal transection at C1 or between C3 and C7. 2. All neurons were antidromically activated from the contralateral thalamus and thoracic spinal cord. For us to accept a neuron for analysis, the characteristics of the somatic input and the latency and shape of the antidromatic spike produced by spinal cord stimulation had to be the same before and after the spinal transection. Also, spinal transection often causes a marked increase in spontaneous cell activity, which may affect the magnitude of an inhibitory response. To avoid this confounding problem, a cell was accepted for analysis only if it showed marked inhibition of high cell activity evoked by somatic pinch before spinal transection. For analysis 13 STT neurons met these criteria: 6 neurons were in monkeys with C1 transections, and 7 neurons were in animals with transections between C3 and C7.(ABSTRACT TRUNCATED AT 250 WORDS)

Responses of neurons in ventroposterolateral nucleus of primate thalamus to urinary bladder distension

The purpose of this study was to examine effects of a noxious visceral stimulus, urinary bladder distension (UBD), on cells in the ventroposterolateral (VPL) nucleus of anesthetized monkeys. We hypothesized that processing of visceral information in the VPL nucleus of the thalamus is similar to spinothalamic tract (STT) organization of visceral afferent input. Urinary bladder distension excites sacral and upper-lumbar STT cells that have somatic input from proximal somatic fields; whereas, thoracic STT cells are inhibited by UBD. Extracellular action potentials of 67 neurons were recorded in VPL nucleus. Urinary bladder distension excited 22 cells, inhibited 9 cells, and did not affect activity of 36 cells. Seventeen of 22 cells excited by UBD also received convergent somatic input from noxious squeeze of the hip, groin, or perineal regions. No cells activated only by innocuous somatic stimuli were excited by UBD. Five of 9 cells inhibited by UBD had upper-body somatic fields. There was a significant tendency for VPL neurons excited by UBD to have proximal lower-body somatic fields that were excited by noxious stimulation of skin and underlying muscle (P less than 0.001). Antidromic activation of 4 thalamic neurons affected by UBD showed that visceral input stimulated by UBD reached the primary somatosensory (SI) cortex.

Inhibitory effects of phrenic afferent fibers on primate lumbosacral spinothalamic tract neurons

Studies were conducted to determine if electrical or mechanical stimulation of phrenic afferent fibers (PHR) would inhibit the activity of lumbosacral spinothalamic tract (STT) neurons. Twelve monkeys were anesthetized, paralyzed, and artificially ventilated. Extracellular action potentials were recorded from 78 STT neurons located in L2-S3 spinal segments. Electrical stimulation of PHR reduced the activity of 65%, did not affect 33%, and excited 1% of STT neurons. Mechanical stimulation of the diaphragm reduced the activity of 63%, did not effect 34%, and excited 1% of lumbosacral STT neurons. Distention of the urinary bladder (UBD) inhibited 52%, did not affect 23%, excited 23%, and elicited a biphasic response in 1% of STT neurons. However, there was no correlation between the effect of PHR and UBD or somatic classification of the neurons. We conclude that electrical or mechanical stimulation of PHR can produce a generalized inhibition of lumbosacral STT neurons. This inhibitory effect of PHR is similar to inhibitory effects reported for a variety of other afferent systems.

Projection of nodose ganglion cells to the upper cervical spinal cord in the rat

Afferent fibers mediating pain from myocardial ischemia classically are believed to travel in sympathetic nerves to enter the thoracic spinal cord. After sympathectomies, angina pectoris still may radiate to the neck and inferior jaw. Sensory fibers from those regions are thought to enter the central nervous system through upper spinal cord segments. We postulated that axons from nodose ganglion cells might project to cervical cord segments. The purpose of this study was to determine the density and pathway of vagal afferent innervation to the upper cervical spinal cord. Following an injection of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) into the upper cervical spinal cord, approximately 5.8% of cells in the nodose ganglion contained reaction product. Cervical vagotomy did not diminish the density of WGA-HRP labeled cells in the nodose ganglion. However, a spinal cord hemisection cranial to the injection site eliminated labeling of nodose cells. These data indicate that a portion of vagal afferent neurons project from the nodose ganglion to the upper cervical spinal cord. In addition, vagal afferent fibers reach the spinal cord via a central route rather than through dorsal root ganglia.

Convergence of phrenic and cardiopulmonary spinal afferent information on cervical and thoracic spinothalamic tract neurons in the monkey: implications for referred pain from the diaphragm and heart

1. Spinothalamic tract (STT) neurons in the C3-T6 spinal segments were studied for their responses to stimulation of phrenic and cardiopulmonary spinal afferent fibers. A total of 142 STT neurons were studied in 44 anesthetized, paralyzed monkeys (Macaca fascicularis). All neurons were antidromically activated from the ventroposterolateral nucleus and/or medial thalamus. 2. Electrical stimulation of phrenic afferent fibers (PHR) excited 43/58 (74%), inhibited 2/58 (3%), and did not affect 13/58 (13%) of cervical STT neurons. Neurons with excitatory somatic fields confined to the proximal limb or encompassing the whole limb were excited to a significantly greater extent by electrical stimulation of PHR than were neurons with somatic fields confined to the distal limb. Mechanical stimulation of PHR by probing the exposed diaphragm excited 11/22 (50%), inhibited 3/22 (14%), and did not affect 8/22 (36%) cervical STT neurons. 3. The technique of minimum afferent conduction velocity (MACV) was used to obtain information about the identity of the PHR that excited 35 cervical STT neurons. Evidence was obtained for excitation of these neurons by group II and III PHR. The mean +/- SE MACV for all neurons was 14 +/- 2 m/s. 4. Electrical stimulation of cardiopulmonary spinal afferent fibers excited 41/57 (72%), inhibited 8/57 (14%), and did not affect 8/57 (14%) of cervical STT neurons. Neurons with excitatory somatic fields confined to the proximal limb or encompassing the whole limb were excited to a significantly greater extent by electrical stimulation of cardiopulmonary spinal afferents than were neurons with somatic fields confined to the distal limb. 5. Excitatory convergence of PHR and cardiopulmonary spinal afferent input was observed for 36/57 (63%) cervical STT neurons. 6. Electrical stimulation of PHR excited 36/84 (43%), inhibited 25/84 (30%), and did not affect 23/84 (27%) of thoracic STT neurons. All of these neurons received excitatory cardiopulmonary spinal afferent input. 7. Neurons were more likely to be excited by electrical stimulation of PHR if they were located in C3-C6 spinal segments. Furthermore, the net excitatory effect of PHR input decreased in more caudal segments, such that thoracic STT neurons were weakly excited relative to cervical STT neurons. 8. We conclude that cervical STT neurons with excitatory somatic fields that include or are restricted to proximal sites are excited by electrical or mechanical stimulation of PHR. Those effects demonstrate a physiological substrate for pain referred from the diaphragm to the shoulder in patients with pleural effusions or subphrenic abscesses.(ABSTRACT TRUNCATED AT 400 WORDS)

Urinary bladder and hindlimb stimuli inhibit T1-T6 spinal and spinoreticular cells

Upper thoracic spinal neurons are primarily excited by cardiopulmonary spinal afferent input but are excited and inhibited by splanchnic afferent input. These data suggest that the greater the number of segments between a spinal neuron and spinal afferent input the greater the probability that the afferent input will inhibit the spinal neuron. Based on this idea we hypothesized that visceral (urinary bladder) and somatic (hindlimb) afferent input would inhibit upper thoracic spinal neurons. To test this hypothesis the activities of 69 spinal and 27 spinoreticular tract neurons in 45 alpha-chloralose-anesthetized cats were studied. Only neurons excited by both visceral and somatic thoracic afferent input were studied. Urinary bladder distension (UBD) inhibited 48 (50%), excited 6 (6%), and did not affect 41 (43%) of these neurons. Also, UBD inhibited the excitatory responses of these cells to noxious visceral and somatic stimuli. Hindlimb pinch also inhibited greater than 50% of the neurons. These data indicate that visceral and somatic afferent input to the lumbosacral spinal cord inhibits the activity of upper thoracic neurons. This inhibitory effect may play a role in localization of sensory and motor responses to noxious stimuli.

Effects of intracardiac bradykinin and capsaicin on spinal and spinoreticular neurons

The responses of thoracic spinal and spinoreticular tract (SRT) neurons to activation of cardiac spinal afferents by injections of bradykinin (BK) and capsaicin (CAP) into the left atrium or pericardial sac were determined in vagotomized cats anesthetized with alpha-chloralose. Activities of spinal and SRT neurons in the T1-T5 spinal cord were recorded extracellularly. All neurons received excitatory somatic and cardiopulmonary sympathetic afferent input. Application of BK and CAP to the heart excited most SRT neurons and many spinal neurons but also inhibited some spinal neurons. The two drugs often affected spinal but not SRT neurons differently. Capsaicin excited high threshold and high threshold inhibitory neurons but not wide-dynamic range spinal neurons. In contrast, BK excited all three categories of spinal and SRT neurons. The differential responses of spinal neurons to intracardiac BK and CAP suggested that these compounds can stimulate functionally different populations of cardiac sympathetic afferents.

Cardiac and abdominal vagal afferent inhibition of primate T9-S1 spinothalamic cells

Effects of electrically stimulating vagal afferents were determined on lumbosacral spinothalamic tract (STT) neurons in the T9-S1 segments. Stimulating left or right vagal afferents inhibited 20 (50%) and excited 4 (10%) of 40 STT neurons. Vagal stimulation reduced activity of the 20 inhibited cells by 71 +/- 6% and reduced the average activity of all 40 STT neurons by 28% from 11.5 +/- 1.3 to 8.3 +/- 1.4 impulses/s (P less than 0.01). Effects of activating thoracic and abdominal or just abdominal vagal afferents were also determined. Stimulating right abdominal vagal afferents inhibited 4 (11%), excited 1 (3%), and did not affect 30 (86%) of the STT neurons and overall did not significantly affect STT cell activity. In contrast, in 33 of these cells stimulation of afferents in the right cervical vagus inhibited 16 (48%), excited 2 (6%), and did not affect 15 (45%) neurons and overall significantly reduced cell activity by 29% (P less than 0.01). These data and those of Ammons et al. (J. Neurophysiol. 50: 926-940, 1983; Circ Res. 53: 603-612, 1983; J. Neurophysiol. 54: 73-89, 1985) suggest that cardiopulmonary but not abdominal vagal afferent input reduces STT cell activity in many spinal segments. This inhibitory vagal reflex may play a role in protecting the heart.

Effects of chemical and electrical stimulation of the midbrain on feline T2-T6 spinoreticular and spinal cell activity evoked by cardiopulmonary afferent input

Responses to electrical and chemical stimulation of the periaqueductal gray (PAG) and midbrain reticular formation (RF) were examined on extracellular activity of 28 spinoreticular tract (SRT) and 56 spinal neurons in T2-T6 segments of anesthetized cats. All cells received excitatory viscerosomatic convergent input from the left forelimb triceps region and from cardiopulmonary sympathetic afferents. Evoked activity that resulted from pinching the left triceps was reduced by PAG and midbrain RF stimulation (100 Hz, 100 microseconds, 50-500 microA). Visceral afferent input to the neurons was elicited during electrical stimulation of cardiopulmonary sympathetic afferent fibers and following injection of bradykinin into the left atrium of the heart. Electrical stimulation of the PAG and adjacent RF decreased A-delta and C-fiber activation of these neurons produced during electrical stimulation of cardiopulmonary afferents and decreased the activity of cells during excitatory responses to intracardiac bradykinin. Electrical stimulation of the PAG or midbrain RF similarly decreased spontaneous and evoked cell activity. Selective activation of cell bodies with microinjection of glutamate into the PAG reduced the activity of 6 of 8 cells whereas glutamate injections into midbrain RF reduced the activity of only 3 of 13 neurons. This difference in the effectiveness of chemically stimulating the PAG vs midbrain RF was significant (P less than 0.05). These data demonstrate that (1) neuronal activity evoked by visceral afferent input from the heart was decreased by electrical stimulation of the PAG and midbrain RF and (2) a portion of this descending inhibition may be mediated by cell bodies in the PAG.

Establishing clinical and immunologic criteria for diagnosis of occupational immunologic lung disease with phthalic anhydride and tetrachlorophthalic anhydride exposures as a model

Using a questionnaire and serum antibody studies, we evaluated 13 workers exposed to phthalic anhydride (PA) and tetrachlorophthalic anhydride (TCPA). The questionnaire was designed to identify symptoms compatible with anhydride-induced immunologic or irritant syndromes. Specific IgG and IgE for both PA-human serum albumin (PA-HSA) and TCPA-HSA were determined by enzyme-linked immunosorbent assay in two different laboratories. In addition, 11 workers had cutaneous testing with PA-HSA and TCPA-HSA, and nine workers were interviewed. One worker was found to have PA-associated asthma and rhinitis. We conclude that a questionnaire and serologic assays for specific IgG and IgE are helpful to identify workers who have or are at risk for developing occupational immunologic lung disease such as those induced by anhydrides. However, additional evaluation may be necessary in those workers with such diseases as intrinsic asthma that may be difficult to differentiate from occupational immunologic lung disease.

Prevention of chymopapain anaphylaxis by screening chemonucleolysis candidates with cutaneous chymopapain testing. A preliminary report

The risk of anaphylaxis in candidates for chemonucleolysis for herniated lumbar discs is approximately 1%. An investigation was designed to eliminate or reduce the incidence of chymopapain anaphylaxis. The procedure was to restrict chemonucleolysis to patients who are prick test-negative to chymopapain at a concentration of 10 mg/ml. The authors skin-tested 292 chemonucleolysis candidates; five were positive and 287 were negative. None of the positive patients were injected with chymopapain. There were no instances of unequivocal chymopapain anaphylaxis in the skin test-negative group. This 0% incidence of anaphylaxis in skin test-negative patients was compared with a population estimate of 1%, based on historical data. The resulting value of p = 0.08 value fell short of the conventional level of significance of 0.05. The p value will reach 0.05 when the series of skin test-negative patients without anaphylaxis reaches 360. It is important that this information is readily available to physicians concerned about anaphylactic reactions to chymopapain.

Levels and specificity of antibody in bronchoalveolar lavage (BAL) and serum in an animal model of trimellitic anhydride-induced lung injury

A study was undertaken to characterize the antibody response in rats exposed to trimellitic anhydride (TMA) by inhalation. Total antibody levels directed to trimellitic rat serum albumin (TM-RSA) from TMA-exposed rats were assayed by an ammonium sulfate technique. Total antibody levels in bronchoalveolar lavage (BAL) and the matched serum were compared by correction for the albumin content of each. An ELISA was developed to detect IgG, IgA, and IgM directed toward TM-RSA in BAL and serum and to compare class-specific antibody levels in BAL and serum by normalizing for albumin content. The specificity of the rat IgG response was determined by ELISA inhibition with TM-RSA and TM-human serum albumin (TM-HSA) and compared with reciprocal inhibition studies with serum from TMA-exposed workers. The levels of total antibody in BAL were three to 15 times greater than the levels found in the matched serum pair. IgG, IgA, and IgM antibodies were detected in the BAL and the serum of TMA-exposed rats but not in control rats. In each of the four rats tested, all antibody classes were present in equal or greater amounts in the BAL than in the serum. Complete inhibition of the rat IgG binding in ELISA was observed when TM-RSA or TM-HSA were added as inhibitors. Human IgG was inhibited in ELISA only by TM-HSA. In an animal model of human lung disease, the levels of total antibody as well as class-specific antibodies directed against TM-RSA were greater in BAL than in serum.(ABSTRACT TRUNCATED AT 250 WORDS)

Provocative challenge with local anesthetics in patients with a prior history of reaction

Possible allergic sensitivity to local anesthetic agents remains problematic for some patients who could benefit from their use. We retrospectively reviewed all our consultations for evaluation of local anesthetic allergy from 1965 to 1985 to assess the safety and efficacy of skin testing and provocative test dosing with a variety of local anesthetic agents. Fifty-nine patients reported 70 reactions from the administration of six different local anesthetics. Fifty-four patients could name one or more local anesthetic agents they believed were responsible, and five patients named only "caine" drugs. Multiple reactions of the same type to the same agent were considered as one reaction. On the basis of their history of reaction, the patients were categorized as follows: anaphylactoid reactions (urticaria, angioedema, wheezing, or hypotension within 1 to 2 hours of exposure), possible anaphylactoid reactions (tachycardia, dizziness, syncope, breathlessness, or pruritus occurring within 1 to 2 hours of exposure), contact dermatitis (a typical eczematous skin eruption after appropriate cutaneous sensitization), and other reactions (nonanaphylactoid reactions other than those already described or those occurring more than 2 hours after exposure). Fifty-nine patients were administered local anesthetics after skin testing and provocative test dosing, including two patients who required intravenous lidocaine (Xylocaine; Astra Pharmaceutical Products, Inc., Westboro, Mass.) acutely to control cardiac arrhythmias. These two patients had reported anaphylactoid reactions to oral antiarrhythmic drugs of the local anesthetic class. Despite the history of previous reactions, there were no positive skin tests or positive provocative drug challenges in any patients.(ABSTRACT TRUNCATED AT 250 WORDS)

A model of immunologic lung injury induced by trimellitic anhydride inhalation: antibody response

We studied lung injury induced in Sprague-Dawley rats by trimellitic anhydride (TMA) inhalation. Groups of 40 male and 20 female rats were exposed to TMA by inhalation at target concentrations of 0, 10, 30, 100, and 300 micrograms/m3, 6 hours per day, 5 days per week, for 2 weeks. Rats in each exposure group were sacrificed after 10 exposures or rested for 12 days and either sacrificed or received a 6-hour TMA challenge at their initial exposure levels and sacrificed at 24 hours. At each sacrifice, serum antibody to radiolabeled trimellityl rat serum albumin (RSA-TM) was measured by an ammonium sulfate technique, and lung pathology was determined. After 10 days of exposure, external hemorrhagic lung foci were directly related to the exposure concentration of TMA. Serum antibody binding of RSA-TM correlated with exposure concentration, hemorrhagic lung foci, and lung weight. There was healing of lung lesions 12 days after exposure with a return of lung lesions only 18 hours after the 6-hour inhalation challenge. A correlation between serum antibody to RSA-TM, hemorrhagic foci, and lung weight existed after challenge. This model clarifies two clinical entities observed in exposed workers, the late respiratory systemic and the pulmonary disease-anemia syndromes.

Psychosomatic nasal disorder

Present day allergy therapy can provide substantial symptomatic relief to patients with allergic and nonallergic rhinitis. Available measures are so effective that treatment failures with our most potent medications should raise the question of the presence of genuine pathology. Psychosomatic symptoms often involve nasal function. We present three such cases in which failure to relieve symptoms suggested a neurotic fixation on the condition of the nose and no demonstrable nasal pathology.

Noncompliance and prevarication in life threatening adolescent asthma

Four cases of noncompliant steroid dependent adolescent asthmatics who intentionally lied about their compliance are presented. All four were followed in the Allergy Clinic at Northwestern Memorial Hospital. Each had psychosocial or family problems which contributed to deliberate failure to take necessary medications and then to lie about it. Frequent E. R. visits, missed school, and hospitalizations for life threatening asthma attacks were seen in these patients. Changes in personal patient patterns of asthma, lack of predicted response to adequate therapeutic regimens, and obvious lack of proper parental supervision were the clues to the correct diagnosis. Undetectable serum prednisolone levels confirmed the diagnosis in one case. We describe the clinical course of these patients including confrontation about noncompliance and therapeutic regimens that have resulted in control of their asthma.

Adenylate cyclase activity and motor behavior following cerebral ischemia in the unanesthetized gerbil

Five minutes of bilateral carotid occlusion in unanesthetized gerbils produced substantial changes in spontaneous locomotor activity. Behavior was decreased after 1 hr of reperfusion and was increased at 24 hrs post-ischemia. Adenylate cyclase activity was measured in homogenates of frontal cortex and hippocampus at 90 min and 24 hrs following 5 min of cerebral ischemia. Enzyme activity was determined in the absence and presence of the activators guanosine-5'-triphosphate (GTP), guanylyl-5'-imidodiphosphate (GppNHp), isoproterenol (Iso) plus GTP, and forskolin (Fors) plus GTP. Homogenates responded with expected increases over basal adenylate cyclase activity with addition of all activators. An additional small increase in isoproterenol-stimulated activity was observed in frontal cortex homogenates at 90 min post-ischemia. No other significant changes in adenylate cyclase activity were observed after either 90 min or 24 hrs of reperfusion. The substantial increases in locomotor activity evident at 24 hrs after transient ischemia are not associated with measurable changes in adenylate cyclase activity in homogenates of frontal cortex or hippocampus.

An unanesthetized-gerbil model of cerebral ischemia-induced behavioral changes

A surgical procedure has been developed to study the effects of cerebral ischemia in the unanesthetized Mongolian gerbil. The methodology is based upon the surgical isolation and instrumentation of both common carotid arteries. A loop of dental floss is placed around each carotid artery and passed through double lumen catheter material; this allows for later occlusion of the carotid arteries and their release in unanesthetized subjects. Functional changes following transient carotid artery occlusion are readily demonstrated by the occurrence of altered spontaneous locomotor activity at various times postischemia. This model should be useful in the evaluation of potential therapeutic agents in the treatment of cerebral ischemia.