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Objective: To examine the impact of electroacupuncture (EA) at the 'four sacral points' on urge urinary incontinence (UUI)., Methods: Twenty-five patients diagnosed with UUI or urgency-predominant mixed urinary incontinence (MUI) were treated by EA at the 'four sacral points'. EA was performed in the sacrococcygeal region using disposable sterile 0.40-mm-diameter acupuncture needles that were either 100 or 125 mm in length. Treatments were delivered once every other day. Before and after treatment, a questionnaire measuring symptom severity and quality of life associated with UUI was administered., Results: The median total score (interquartile range) from the severity of symptoms and the quality of life questionnaire (Q-score) of the participants was significantly reduced from 12 (7.5, 15) before treatment to 3 (0, 6) after 6 (6, 12) EA treatments. The Q-score of urgency-predominant MUI and UUI was 8 (5, 14.5) and 12.5 (11, 15), respectively, before treatment; after treatment these were reduced to 2 (0, 7.5) and 4.5 (2, 6), respectively. There was no statistically significant difference in the Q-score between urgency-predominant MUI and UUI before and after treatment. Upon treatment completion, seven patients (28%) were 'cured' (improvement rate 100%). Treatments were considered 'markedly effective' (improvement rate 75% to <100%) in four patients (16%), 'effective' (improvement rate 50% to <75%) in eight patients (32%), 'minimally effective' (improvement rate 25% to <50%) in three patients (12%), and 'ineffective' (improvement rate <25%) in three patients (12%). The overall success rate (comprising 'cured', 'markedly effective' and 'effective' categories) was 76%, and no adverse effects associated with acupuncture treatment were reported., Conclusion: EA at the 'four sacral points' was associated with statistically significant improvements in UUI.

Introduction: Prolonged surgery is a known risk of pressure ulcer formation. Pressure ulcers affect the quality of life, are a significant cause of morbidity and mortality, and pose a burden on the healthcare system. This study aimed to compare the effectiveness of an alternating pressure (AP) overlay with Gel pad against the Gel pad in reducing interface pressure (IP) during prolonged surgery., Methods: A total of 180 participants from a tertiary hospital were randomized to AP overlay with Gel pad group (n = 90) and Gel pad group (n = 90). Patients were placed supine on the pressure redistributing surfaces, and IP data under the sacrum and ischial tuberosities were collected at an interval of 30 min from 0 min up to a maximum of 570 min., Results: Based on data from 133 participants, the average IPs during all the deflation cycles of the AP overlay (with Gel pad) were significantly lower than the average continuous IP recorded for Gel pad throughout the measuring period (p < 0.001). Only three patients (2.26% of study participants) - Gel pad group (n = 2; 2.99%) and AP overlay with Gel pad group (n = 1; 1.52%) developed post-operative pressure ulcer (p = 0.5687)., Conclusions: The lower IP during deflation cycles of the AP overlay (with Gel pad) suggests its potential effectiveness in preventing pressure ulcer formation in patients undergoing prolonged surgery. The prevention and reduction of pressure ulcers will have a considerable impact on the improved quality of life and cost savings for the patient. The study findings may facilitate the formulation of policies for preventing pressure ulcer development in the perioperative setting., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Aim: To evaluate the changes that take place in the perfusion, oxygenation and local temperature of the skin of the sacrum and trochanter when subjected to direct pressure for 2 h., Methods: Quasi-experimental study in the preclinical phase with healthy subjects acting as their own controls (intrasubject control). The outcome variables were measured with a laser Doppler system (local temperature and oxygenation) and by near-infrared spectroscopy (perfusion). The pressure exerted was measured with a capacitive pressure sensor. No more than one week elapsed between the sacrum and trochanter measurements., Results: The study sample consisted of 18 persons. The comparative analysis of the fluctuations in the parameters measured on the skin of the trochanters and sacrum, according to the time elapsed, revealed a statistically significant increase in temperature and in the pressure exerted. On the other hand, the changes in capillary blood flow and in SaO2 were not statistically significant., Conclusion: Our study results show that changes found in terms of temperature and pressure should be taking into account when planning personalised repositioning to patients according to biomechanical and biological situations that vary between anatomical areas. In future research, the changes reported could be evaluated in patients with risk factors for the development of pressure ulcers, thus facilitating the introduction of more personalised planning in the care and prevention of these injuries., (Copyright © 2021 Tissue Viability Society. Published by Elsevier Ltd. All rights reserved.)

Introduction: Chondromalacia patella is the degeneration of articular cartilage on the posterior facet of the patella and may indicate the onset of osteoarthritis. Conservative management is the main treatment option, and surgical intervention is considered the last option in a small percentage of patients. Perineural Injection Treatment (PIT) is a recently developed treatment option that is directed adjacent to the peripheral nerves that are the source of pathology causing neurogenic inflammation and pain. Objective: The objective of this study was to evaluate the efficacy of PIT combined with a home physical therapy program in patients with a diagnosis of chondromalacia patella compared with a control group receiving physical therapy only. Methods: Two patient groups were involved in this randomized clinical trial. The first received PIT combined with physical therapy (PIT + PT group) and the second was managed with physical therapy alone (PT group). Both groups were indicated to follow a 6-week home therapy plan afterward. The Western Ontario and McMaster Osteoarthritis Index was used to assess the patients at baseline and 6 months after therapy interventions. Results: Fifty patients (38 women and 12 men, median age 54.7 ± 14.8 years) were included; sex distribution and age did not differ between groups. Both groups had chondromalacia grade II or III, but the degree of gonarthrosis did not differ significantly between groups. The PIT + PT group outperformed PT group for pain (7.3 ± 3.5 vs. 3.2 ± 2.9 points; p  < 0.010), stiffness (3 ± 1.69 vs. 1.6 ± 1.5 points; p  < 0.010), and functional capacity (23.2 ± 10.7 vs. 11.1 ± 8.9 points; p  < 0.010). Conclusions: Compared with physical therapy alone, PIT plus physical therapy reduced pain and stiffness and restored functional capacity. ClinicalTrials.gov Register Number #NCT03515720.

Introduction: Pressure ulcers present significant trauma to patients and are expensive to manage. In medical imaging (MI), no study has been conducted to rigorously investigate interface pressure (IP) risk on MI table surfaces. IP is defined as the pressure between human body and a supporting surface. The aims of this research were to investigate whether IP risks exist on MI table surfaces and to assess pain and comfort when lying on MI table surfaces., Methods: A calibrated XSENSOR mat was used to measure IP for three jeopardy areas (head, sacrum, and heels) in healthy volunteers on an x-ray table surface with no mattress, an x-ray table surface with a thin radiolucent mattress, and a computed tomography table surface, after which they completed a pain and comfort questionnaire., Results: The sample consisted of 26 females and 23 males aged 18-59 years (mean = 34.6; standard deviation [SD] = 10.5). Analysis of variance identified statistically significant differences in the mean IP for the jeopardy areas across the three MI table surfaces (P ≤ .001). Results also indicated high mean IP value for the head (75.9 mmHg; SD = 6.9) on the x-ray table with no mattress. Seventy percent of the volunteers found lying on the x-ray table with no mattress to be very uncomfortable. Sixty-seven percent experienced most pain whilst lying on the x-ray table with no mattress and over 81% of the pain occurred at the head., Conclusion: IP risk exists on x-ray tables with no mattress. This could increase the risk of developing pressure ulcers in patients accessing prolonged radiography/radiology procedures., (Copyright © 2018. Published by Elsevier Inc.)

Background: One of the most common orthopedic problems is the incidence of pressure ulcer followed by immobility. This study aimed to investigate the effect of Aloe Vera gel on the prevention of pressure ulcer in patients hospitalized in the orthopedic ward., Method: This study is a randomized, triple-blind clinical trial which was done on 80 purposefully selected patients in orthopedic ward in Arak town, Iran, 2016. Patients were randomly assigned into two intervention and control groups based on blocking sampling method. In each group the routine daily cares to prevent bed sores were performed by nurses. In the intervention group in addition to routine nursing care to prevent bed sores, twice a day (hours of 9 and 21) pure Aloe Vera gel on the areas of hip, sacrum and heel were rubbed, but in the control group placebo (gel of water and starch) were used. Then sacral, hip and heel of both groups on days 3, 7 and 10 for of signs of pressure ulcers was evaluated., Results: The mean age of patients in the control group was (42.34 ± 12.19) and in the intervention group Was (41.71 ± 11.50) years, respectively. In the intervention group 1 patient afflicted with sore of hip and two people with sacral pressure ulcer. In the control group 3 patients affiliated with sore of hip, 8 people with sacral pressure ulcer, and 1 person had pressure sore of heel. Analysis of the data showed that both groups had statistically significant differences in the incidence of pressure ulcers (P = 0.047). This means that Aloe Vera gel could prevent the occurrence of pressure ulcers in the intervention group., Conclusion: Due to the effect of Aloe Vera gel to prevent a rise in temperature, non-blanchable redness, swelling and pain of the skin of regions under study in hospitalized patients in the orthopedic ward, applying of it toward the prevention of pressure ulcers in patients at risk of pressure ulcer development is recommended., Trial Registration: This study was registered in Iranian Registry of Clinical. Trials in 07/09/2016 with the IRCT ID: IRCT2016051027825N1 .

Purpose: The sacrum is the most common location of pressure injuries (PIs) in bedridden patients. The purpose of this study was to measure the effect of specific pressure preventive devices on sacral skeletal muscle, subcutaneous fat, and skin tissue deformations., Subjects and Setting: The sample comprised 3 healthy adults residing in a community setting in Tel Aviv, Israel., Design: Descriptive, comparative design., Methods: Tissue thickness changes of 3 healthy adults were measured using magnetic resonance imaging (MRI) in weight-bearing sacral skin, subcutaneous fat, and muscle. Changes in tissue thickness were compared under the following conditions: (1) lying supine on a rigid surface (unpadded MRI table), (2) lying on a standard foam mattress, (3) lying on a mattress after application of a prophylactic multilayer dressing, and (4) lying on a standard foam mattress with a prophylactic multilayer dressing and a positioning system. One-way analysis of variance and post hoc Tukey-Kramer multiple pairwise comparisons were used to compare outcomes., Results: The mattress, the prophylactic multilayer dressing, and the turning and positioning device when applied together resulted in significantly lower deformation levels of each of the soft tissue layers (ie, skin, subcutaneous fat, and muscle separately) as well as of the total soft tissue bulk, with respect to the rigid MRI table (P < .05)., Conclusion: Study findings suggest that a combination of preventive interventions may reduce the risk of developing a sacral PI.

We reviewed the available studies on efficacy and safety of percutaneous tibial nerve stimulation (PTNS) and sacral nerve modulation (SNM) for overactive bladder (OAB) symptoms not responsive to conservative treatments. We limited our search to randomized trials, in English, with at least 20 adult patients, and 6 mo and 12 wk of follow-up for SNM and PTNS, respectively, published between January 1998 and December 2017. Therapeutic success ranges from 61% to 90% for SNM and from 54% to 79% for PTNS. Both techniques are effective and safe, with no life-threatening adverse effects. PTNS is a less invasive technique that gives good results in short time with fewer side effects., Patient Summary: Sacral nerve modulation and percutaneous tibial nerve stimulation are effective and safe in patients with overactive bladder syndrome not responsive to standard medical therapy., (Copyright © 2018 European Association of Urology. Published by Elsevier B.V. All rights reserved.)

The ability to improve motor function in spinal cord injury patients by reactivating spinal central pattern generators (CPGs) requires the elucidation of neurons and pathways involved in activation and modulation of spinal networks in accessible experimental models. Previously we reported on adrenoceptor-dependent sacral control of lumbar flexor motoneuron firing in newborn rats. The current work focuses on clarification of the circuitry and connectivity involved in this unique modulation and its potential use. Using surgical manipulations of the spinal gray and white matter, electrophysiological recordings, and confocal microscopy mapping, we found that methoxamine (METH) activation of sacral networks within the ventral aspect of S2 segments was sufficient to produce alternating rhythmic bursting (0.15-1 Hz) in lumbar flexor motoneurons. This lumbar rhythm depended on continuity of the ventral funiculus (VF) along the S2-L2 segments. Interrupting the VF abolished the rhythm and replaced it by slow unstable bursting. Calcium imaging of S1-S2 neurons, back-labeled via the VF, revealed that ∼40% responded to METH, mostly by rhythmic firing. All uncrossed projecting METH responders and ∼70% of crossed projecting METH responders fired with the concurrent ipsilateral motor output, while the rest (∼30%) fired with the contralateral motor output. We suggest that METH-activated sacral CPGs excite ventral clusters of sacral VF neurons to deliver the ascending drive required for direct rhythmic activation of lumbar flexor motoneurons. The capacity of noradrenergic-activated sacral CPGs to modulate the activity of lumbar networks via sacral VF neurons provides a novel way to recruit rostral lumbar motoneurons and modulate the output required to execute various motor behaviors., Significance Statement: Spinal central pattern generators (CPGs) produce the rhythmic output required for coordinating stepping and stabilizing the body axis during movements. Electrical stimulation and exogenous drugs can reactivate the spinal CPGs and improve the motor function in the absence of descending supraspinal control. Since the body-stabilizing sacral networks can activate and modulate the limb-moving lumbar circuitry, it is important to clarify the functional organization of sacral and lumbar networks and their linking pathways. Here we decipher the ascending circuitry linking adrenoceptor-activated sacral CPGs and lumbar flexor motoneurons, thereby providing novel insights into mechanisms by which sacral circuitry recruits lumbar flexors, and enhances the motor output during lumbar afferent-induced locomotor rhythms. Moreover, our findings might help to improve drug/electrical stimulation-based therapy to accelerate locomotor-based rehabilitation., (Copyright © 2017 the authors 0270-6474/17/371294-18$15.00/0.)

Objectives: To investigate the between-day and within-day reliability of a sacral mounted accelerometer to quantify balance performance and different balance metrics., Design: Experimental, cross-sectional., Setting: Laboratorial experiment., Participants: Thirty healthy volunteers., Main Outcome Measures: Balance tasks were double leg stance, tandem stance and single leg stance with eyes open and closed. Performance was measured by converting accelerations into path length (PL, length of the sway trace), jerk (jerkiness of sway trace) and root mean square (RMS) of the accelerations., Results: Within-day ICC for PL were excellent (mean 0.78 95%CI 0.68-0.89), with Jerk and RMS demonstrating means of 0.60 and 0.47, respectively. The mean percentage minimal detectable change (MDC) within-day were small for PL (mean 6.7%, 95%CI 5.3-8.1). Between-day ICC were good for PL (mean 0.61, 95%CI 0.50-0.71), but more varied for Jerk and RMS. The mean percentage MDC was small for PL (mean 6.1%, 95%CI 5.0-7.2). No significant differences were determined for measurements between-days for any metric or task. PL had the highest discriminatory value between the 8 tasks., Conclusions: The sacral mounted accelerometer reliably measured balance performance within- and between-days. The PL is the recommended metric as it was the most reliable, most discriminatory and most sensitive to change., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Purpose: The objective of this study was to quantify tissue interface pressures that occurred in the sacrum, shoulder, and buttock/thigh regions while using (1) pillows or (2) a wedge system for off-loading of sacral pressures., Subjects and Setting: Twenty-one volunteers (11 females and 10 males) residing near a Midwestern, university community consented to participate in the study. Testing was conducted in a hospital bed with pillows and a commercially available wedge system., Methods: Pressures were measured under 3 test conditions: (1) bed alone, (2) pillows positioned above and below the sacral region, and (3) wedges positioned above and below the sacral region. Each condition was tested with the elevation of the head of the bed at 3 different angles with respect to the foot of the bed (0°, 20°, and 30°). Two pressure mats were used to capture data; one was located in the shoulder region and the other in the sacral/buttocks/thigh region., Results: Between the pillows and the wedge, the wedge system was the most effective in reducing pressures on the sacral area. In comparison to the bed condition, both the pillow and wedge conditions produced significantly lower mean sacral pressures than the bed alone (P < .05). Because the pillow and wedge systems tilted the body onto one side, higher pressures were identified on the buttock/thigh when compared to the bed alone (P < .05)., Conclusions: Pressure reduction occurred in the sacral region with the pillow and wedge systems; however, this reduction resulted in increased pressures in the posterior-lateral regions of the buttocks and thighs. When using off-loading devices, consideration should be given to all factors, including tissue interface pressures on the sacrum, increased pressures on other body locations, and the likelihood that these increased pressures will result in tissue damage.

Understanding the central nervous system (CNS) response strategy to trunk perturbations could help in prevention of back injuries and development of rehabilitation and treatment programs. This study aimed to investigate biomechanical response of the trunk musculoskeletal system under sudden forward loads, accounting for pre-perturbation conditions (preloading, initial posture and abdominal antagonistic coactivation) and perturbation magnitudes. Using a trunk kinematics-driven iterative finite element (FE) model, temporal profiles of measured kinematics and external load along with subjects' weights were prescribed to predict thoracolumbar muscle forces/latencies and spinal loads for twelve healthy subjects when tested in six conditions during pre- and post-perturbation periods. Results demonstrated that preloading the trunk significantly (i.e., p<0.05) increased pre-perturbation back muscle forces but significantly decreased post-perturbation peak muscle active forces and muscle latencies. Initial trunk flexion significantly increased muscle active and passive forces before the perturbation and their peak values after the perturbation, which in turn caused much larger spinal loads. Abdominal muscles antagonistic pre-activation did not alter the internal variables investigated in this study. Increase in sudden applied load increased muscle reflex activities and spinal forces; a 50 N increase in sudden load (i.e., when comparing 50 N to 100 N) increased the L5-S1 compression force by 1327 N under 5 N preload and by 1374 N under 50 N preload. Overall, forces on the spine and hence risk of failure substantially increased in sudden forward loading when the magnitude of sudden load increased and when the trunk was initially in a flexed posture. In contrast, a higher initial preload diminished reflex latencies and compression forces., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Aims: Pudendal afferent fibers can be excited using electrical stimulation to evoke reflex bladder activity. While this approach shows promise for restoring bladder function, stimulation of desired pathways, and integration of afferent signals for sensory feedback remains challenging. At sacral dorsal root ganglia (DRG), the convergence of pelvic and pudendal afferent fibers provides a unique location for access to lower urinary tract neurons. Our goal in this study was to demonstrate the potential of microstimulation in sacral DRG for evoking reflex bladder responses., Methods: Penetrating microelectrode arrays were inserted in the left S1 and S2 DRG of six anesthetized adult male cats. While the bladder volume was held at a level below the leak volume, single and multiple channel stimulation was performed using various stimulation patterns., Results: Reflex bladder excitation was observed in five cats, for stimulation in either S1 or S2 DRG at 1 Hz and 30-33 Hz with a pulse amplitude of 10-50 µA. Bladder relaxation was observed during a few trials. Adjacent electrodes frequently elicited very different responses., Conclusions: These results demonstrate the potential of low-current microstimulation to recruit reflexive bladder responses. An approach such as this could be integrated with DRG recordings of bladder afferents to provide a closed-loop bladder neuroprosthesis., (© 2014 Wiley Periodicals, Inc.)

Objective: Clinicians commonly recommend that power wheelchair users with spinal cord injury perform wheelchair tilt and recline maneuvers to redistribute seating loads away from the ischial tuberosities. However, ischial pressure reduction may be accompanied by coccygeal pressure increases. Although the coccyx is among the most common sites of pressure ulcers, few studies have reported coccygeal interface pressure. The purpose of this study was to investigate both ischial and coccygeal interface pressures in response to changes in wheelchair tilt and recline angles., Design: Thirteen power wheelchair users were recruited into this study. Six combinations of wheelchair tilt (15, 25, and 35 degrees) and recline (10 and 30 degrees, corresponding to traditional recline conventions of 100 and 120 degrees, respectively) angles were tested in random order. Each combination was tested with 5 mins of upright sitting, 5 mins of tilt and recline, as well as 5 mins of maximal pressure relief recovery. Peak pressure indices were calculated at the ischial and coccygeal sites., Results: Ischial pressures monotonically decreased in response to increasing combinations of tilt and recline. Increments of 15 degrees of tilt did not produce significant differences under either recline angle, whereas increments of 25 degrees of tilt produced significant differences under both recline angles. Coccygeal pressures increased in response to the four smallest (of six) combinations of tilt and recline, whereas they decreased in response to the largest two combinations., Conclusions: Ischial pressures seemed to be redistributed to the coccyx in response to the four smallest angle combinations and redistributed to the back support in response to the two largest angle combinations. Future work should confirm this pressure redistribution to the back support and determine the back support locations of redistribution.

A common method of genotyping mice is via tissue obtained from tail biopsies. However, there is no available information on the temporal development of sensory neurons in the tail and how their presence or absence might affect the age for performing tail biopsies. The goals of this study were to determine if afferent sensory neurons, and in particular nociceptive neurons, are present in the coccygeal vertebrae at or near the time of birth and if not, when they first can be visualized on or in those vertebrae. Using toluidine blue neuronal staining, transmission electron microscopy, and calcitonin-related gene peptide immunostaining, we found proximal to distal maturation of coccygeal nerve growth in the C57BL/6J mouse. Single nerve bundles were first seen on postpartum day (PPD) 0. On PPD 3 presumptive nociceptive sensory nerve fibers were seen entering the vertebral perichondrium. Neural development continued through the last time point (PPD 7) but at no time were neural fibers seen entering the body of the vertebrae. The effect of age on the development of pain perception in the neonatal mouse is discussed.

Various pelvic floor conditions, including overactive bladder syndrome and chronic pelvic pain, have been successfully managed with the neuromodulation of sacral nerves. Sacral neuromodulation is a minimally invasive procedure involving the implantation of a programmable pulse generator that delivers low-amplitude electrical current via quadripolar tined leads through the S3 foramen. Durable efficacy has been demonstrated in retrospective studies, but questions regarding ideal patient candidacy and optimal technical considerations remain unanswered., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background: Most posture problems encountered in persons who use wheelchairs in a seated posture for extended periods are related to sacral sitting due to posterior pelvic tilt. Posterior pelvic tilt places pressure and shearing force on the sacrococcygeal area that can lead to pressure ulcers, but the relationship between pelvic tilt and force applied to the sacrococcygeal and ischial tuberosity areas has not yet been investigated., Objective: To investigate the relationships of posterior pelvic tilt in a seated posture with vertical force and horizontal force on the sacrococcygeal and ischial tuberosity areas., Study Design: Repeated measures design., Methods: Thirty male and female subjects aged ≥60 years sat in a measurement chair at varying pelvic tilt angles, and force on the sacrococcygeal and ischial tuberosity areas was measured., Results: The pressure on the sacrococcygeal area increased with pelvic tilt in all subjects, with vertical force averaging 19% of the body weight at a pelvic tilt angle of 30°. The horizontal force on the sacrococcygeal area increased in 93% of the subjects, with an average increase equal to 3% of the body weight., Conclusions: We confirmed changes in vertical and horizontal forces on the sacrococcygeal and ischial tuberosity areas with a change in seated posture (pelvic tilt)., Clinical Relevance: We propose guidelines for rehabilitation practitioners working with wheelchair users to suggest improved ways of sitting in wheelchairs that avoid pelvic tilt angles that might promote pressure ulcers on the buttocks.

The purpose of this investigation was conducted to determine the acute effect of passive static stretching (PSS) of the lower-body musculature on lower-body strength in a 1 repetition maximum (1RM) squat exercise in young (18-24 years.) moderately trained men (n = 17). Two supervised warm-up treatments were applied before each performance testing session using a counterbalanced design on nonconsecutive days. The first treatment consisted of an active dynamic warm-up (AD) with resistance machines (i.e., leg extension/leg flexion) and free weights (i.e., barbell squat), whereas the second treatment added PSS of the lower body plus the AD treatment. One repetition maximum was determined using the maximum barbell squat following a progressive loading protocol. Subjects were also asked to subjectively evaluate their lower-body stability during 1RM testing sessions for both the AD and PSS treatments. A significant decrease in 1RM (8.36%) and lower-body stability (22.68%) was observed after the PSS treatment. Plausible explanations for this observation may be related to a more compliant muscle tendon unit and/or altered or impaired neurologic function in the active musculature. It is also possible that strength was impaired by the PSS because of joint instability. The findings of this study suggest that intensive stretching such as lower-body PSS should be avoided before training the lower body or performing the 1RM in the squat exercise in favor of an AD dynamic warm-up using resistance training equipment in the lower-body musculature.

Background: A longitudinal repeated measures design over pregnancy and post-birth, with a control group would provide insight into the mechanical adaptations of the body under conditions of changing load during a common female human lifespan condition, while minimizing the influences of inter human differences. The objective was to investigate systematic changes in the range of motion for the pelvic and thoracic segments of the spine, the motion between these segments (thoracolumbar spine) and temporospatial characteristics of step width, stride length and velocity during walking as pregnancy progresses and post-birth., Methods: Nine pregnant women were investigated when walking along a walkway at a self-selected velocity using an 8 camera motion analysis system on four occasions throughout pregnancy and once post birth. A control group of twelve non-pregnant nulliparous women were tested on three occasions over the same time period. The existence of linear trends for change was investigated., Results: As pregnancy progresses there was a significant linear trend for increase in step width (p = 0.05) and a significant linear trend for decrease in stride length (p = 0.05). Concurrently there was a significant linear trend for decrease in the range of motion of the pelvic segment (p = 0.03) and thoracolumbar spine (p = 0.01) about a vertical axis (side to side rotation), and the pelvic segment (p = 0.04) range of motion around an anterio-posterior axis (side tilt). Post-birth, step width readapted whereas pelvic (p = 0.02) and thoracic (p < 0.001) segment flexion-extension range of motion decreased and increased respectively. The magnitude of all changes was greater than that accounted for with natural variability with re testing., Conclusions: As pregnancy progressed and post-birth there were significant linear trends seen in biomechanical changes when walking at a self-determined natural speed that were greater than that accounted for by natural variability with repeated testing. Not all adaptations were resolved by eight weeks post birth.

Identification of the neural pathways involved in retraining the spinal central pattern generators (CPGs) by afferent input in the absence of descending supraspinal control is feasible in isolated rodent spinal cords where the locomotor CPGs are potently activated by sacrocaudal afferent (SCA) input. Here we study the involvement of sacral neurons projecting rostrally through the ventral funiculi (VF) in activation of the CPGs by sensory stimulation. Fluorescent labeling and immunostaining showed that VF neurons are innervated by primary afferents immunoreactive for vesicular glutamate transporters 1 and 2 and by intraspinal neurons. Calcium imaging revealed that 55% of the VF neurons were activated by SCA stimulation. The activity of VF neurons and the sacral and lumbar CPGs was abolished when non-NMDA receptors in the sacral segments were blocked by the antagonist CNQX. When sacral NMDA receptors were blocked by APV, the sacral CPGs were suppressed, VF neurons with nonrhythmic activity were recruited and a moderate-drive locomotor rhythm developed during SCA stimulation. In contrast, when the sacral CPGs were activated by SCA stimulation, rhythmic and nonrhythmic VF neurons were recruited and the locomotor rhythm was most powerful. The activity of 73 and 27% of the rhythmic VF neurons was in-phase with the ipsilateral and contralateral motor output, respectively. Collectively, our studies indicate that sacral VF neurons serve as a major link between SCA and the hindlimb CPGs and that the ability of SCA to induce stepping can be enhanced by the sacral CPGs. The nature of the ascending drive to lumbar CPGs, the identity of subpopulations of VF neurons, and their potential role in activating the locomotor rhythm are discussed.

Effective quadrupedal locomotion requires a close coordination between the spatially distant central pattern generators (CPGs) controlling forelimb and hindlimb movements. Using isolated preparations of the neonatal rat spinal cord, we explore the role of intervening thoracic circuitry in cervicolumbar CPG coordination and the contribution to this remote coupling of limb somatosensory inputs. In preparations activated with bath-applied N-methyl-D,L-aspartate, serotonin, and dopamine, the coordination between locomotor-related bursts recorded in cervical and lumbar ventral roots was substantially weakened, although not abolished, when the thoracic segments were selectively withheld from neurochemical stimulation or were exposed to a low Ca(2+) solution to block synaptic transmission. Moreover, cervicolumbar CPG coordination was reduced after a thoracic midsagittal section, suggesting that cross-cord projections participate in the anteroposterior coupling. In quiescent preparations, either cyclic or tonic electrical stimulation of low-threshold afferent pathways in C8 or L2 dorsal roots (DRs) could elicit coordinated ventral root bursting at both cervical and lumbar levels via an activation of the underlying CPG networks. When lumbar rhythmogenesis was prevented by local synaptic transmission blockade, L2 DR stimulation could still drive left-right alternating cervical bursting in preparations otherwise exposed to normal bathing medium. In contrast, when the cervical generators were selectively blocked, C8 DR stimulation was unable to activate the lumbar CPGs. Thus, in the newborn rat, anteroposterior limb coordination relies on active burst generation within midcord thoracic circuitry that additionally conveys ascending and weaker descending coupling influences of distant limb proprioceptive inputs to the cervical and lumbar generators, respectively.

In the South American abelisaurids Carnotaurus sastrei, Aucasaurus garridoi, and, to a lesser extent Skorpiovenator bustingorryi, the anterior caudal ribs project at a high dorsolateral inclination and have interlocking lateral tips. This unique morphology facilitated the expansion of the caudal hypaxial musculature at the expense of the epaxial musculature. Distinct ridges on the ventrolateral surfaces of the caudal ribs of Aucasaurus garridoi are interpreted as attachment scars from the intra caudofemoralis/ilio-ischiocaudalis septa, and confirm that the M. caudofemoralis of advanced South American abelisaurids originated from a portion of the caudal ribs. Digital muscle models indicate that, relative to its overall body size, Carnotaurus sastrei had a substantially larger M. caudofemoralis than any other theropod yet studied. In most non-avian theropods, as in many extant sauropsids, the M. caudofemoralis served as the primary femoral retractor muscle during the locomotive power stroke. This large investment in the M. caudofemoralis suggests that Carnotaurus sastrei had the potential for great cursorial abilities, particularly short-burst sprinting. However, the tightly interlocking morphology of the anterior caudal vertebrae implies a reduced ability to make tight turns. Examination of these vertebral traits in evolutionary context reveals a progressive sequence of increasing caudofemoral mass and tail rigidity among the Abelisauridae of South America.

Introduction: Immobilization of patients utilizing rigid spine boards (RSBs) is standard practice in the management of trauma patients. Pressure ulcers have been associated with prolonged immobilization, and the possibility exists that formation may begin when the patient is initially immobilized on the RSB. The effects may not be fully recognized because of limited research on the direct tissue effects of prolonged immobilization. Near-infrared spectroscopy is an emerging tool to measure peripheral tissue oxygen saturation (StO(2)). The purpose of this research was to study the effects of prolonged spinal immobilization on an RSB on sacral tissue oxygenation of healthy volunteers., Methods: This experimental study measured StO(2) in healthy volunteers at baseline and again after 30 minutes of immobilization on an RSB at two sites: the sacral area (intervention) and 8-10 cm above the buttocks (control). Tissue oxygenation was measured with the InSpectra Tissue Oxygenation Monitor (Hutchinson Technology, Hutchinson, MN) by placing the probe at the measurement site and waiting for 15 seconds for equilibration prior to recording StO(2). Data were analyzed utilizing mixed-model and within-subjects analysis of variance (ANOVA), chi-square, and t-tests., Results: Seventy-three participants were included in the analysis. A slight majority of participants were female (55%), the average age was 38 years, the average height was 170 cm, and the average weight was 82 kg. There was a significant increase in the StO(2) percentage at the sacral (intervention) area following immobilization, p < 0.001, point biserial correlation (r(pb)) = 0.48. Significant changes in oxygenation were not noted at the control site., Conclusion: An increase in sacral tissue oxygenation following immobilization was a finding consistent with other research. This is likely a result of initial, rapid tissue reperfusion at the time of pressure release. Rapid reperfusion indicates that a period of previous hypoperfusion has occurred. This research indicates that there are detrimental effects of spine board immobilization in healthy volunteers, which suggests that pressure ulcer formation may begin prior to hospital admission with immobilization on an RSB.

Objective: To determine the effect of IV administration of a bolus of 50% dextrose solution on electrolyte and energy balance and effect of blood collection site on serum electrolyte values in postparturient dairy cows., Animals: 24 clinically normal multiparous cows., Procedures: A bolus of 50% dextrose solution (0.5 L [n=8 cows]), 50% dextrose solution (1.0 L [8]), or saline (0.9% NaCl) solution (1.0 L, control treatment [8]) was administered via jugular venipuncture 5 to 10 days after parturition. Pretreatment and posttreatment blood samples were analyzed for concentrations of calcium, magnesium, phosphorus, potassium, glucose, insulin, beta-hydroxybutyric acid (BHBA), and nonesterified fatty acids. Coccygeal vessel and jugular vein blood samples were obtained prior to treatment, and electrolyte concentrations were compared., Results: Treatment with 50% dextrose decreased phosphorus concentration in serum, compared with the control treatment. Suppression of BHBA and nonesterified fatty acid concentrations following dextrose treatment lasted for <12 hours; mean BHBA concentrations in all groups were increased 24 hours after treatment. Mean serum phosphorus concentration in coccygeal vessel blood samples was 0.67 mg/dL greater than the concentration in jugular vein blood samples., Conclusions and Clinical Relevance: Postpartum cows treated with dextrose solution may be at risk for hypophosphatemia, and 1 treatment with 0.5 or 1 L of 50% dextrose solution is unlikely to prevent or resolve acetonemia (ketosis). The risk of hypophosphatemia may be underestimated when coccygeal vessel blood samples are used for diagnosis.

Magnetoencephalography (MEG) was used to measure the somatosensory evoked fields in six healthy males undergoing sacral surface therapeutic electrical stimulation, a recently introduced treatment for chronic urinary dysfunction. This study was performed to investigate the utility of MEG to optimize the stimulation parameters. Strong or weak electrical stimuli were applied to small or large surface electrodes placed over the bilateral sacral surfaces. The peak latency and strength of the equivalent current dipole were evaluated at the first peak originating from the primary somatosensory cortex (M30). There was no difference in M30 latency in response to stimulation intensity or electrode size. However, a larger equivalent current dipole strength was obtained in response to higher stimulus intensities, which indicated a more effective stimulus on the sacral surface. The present MEG study shows that stronger stimuli given through large electrodes evoke larger responses than small stimuli through small electrodes. The study also suggests that MEG can be used as an objective tool to monitor whether therapeutic stimulation parameters are appropriate.

Urinary retention without an identifiable urological cause presents a diagnostic and therapeutic challenge. Patients with nonobstructive chronic urinary retention usually have to rely on intermittent self-catheterization or indwelling suprapubic or transurethral catheters, which significantly affect quality of life. For some patients, however, sacral neuromodulation (SNM) offers an effective therapeutic alternative, and women with primary disorder of urethral sphincter relaxation (Fowler's syndrome) seem to respond particularly well to this treatment. Although the mechanism of action of SNM is not well understood and requires further investigation, it seems to involve afferent mediation of spinal cord reflexes and brain networks. The evolution of SNM devices and improvements in surgical and testing techniques, especially the introduction of the two-stage tined lead procedure, have considerably reduced the failure, adverse event and surgical revision rates associated with SNM, ensuring that this modality is an effective minimally invasive treatment for urinary retention.

The purpose of this study was to examine the extent of activation in various trunk muscles during dynamic weight-training and isometric instability exercises. Sixteen subjects performed squats and deadlifts with 80% 1 repetition maximum (1RM), as well as with body weight as resistance and 2 unstable calisthenic-type exercises (superman and sidebridge). Electromyographic (EMG) activity was measured from the lower abdominals (LA), external obliques (EO), upper lumbar erector spinae (ULES), and lumbar-sacral erector spinae (LSES) muscle groups. Results indicated that the LSES EMG activity during the 80% 1RM squat significantly exceeded 80% 1RM deadlift LSES EMG activity by 34.5%. The LSES EMG activity of the 80% 1RM squat also exceeded the body weight squat, deadlift, superman, and sidebridge by 56, 56.6, 65.5, and 53.1%, respectively. The 80% 1RM deadlift ULES EMG activity significantly exceeded the 80% 1RM squat exercise by 12.9%. In addition, the 80% 1RM deadlift ULES EMG activity also exceeded the body weight squat, deadlift, superman, and sidebridge exercises by 66.7, 65.5, 69.3, and 68.6%, respectively. There were no significant changes in EO or LA activity. Therefore, the augmented activity of the LSES and ULES during 80% 1RM squat and deadlift resistance exercises exceeded the activation levels achieved with the same exercises performed with body weight and selected instability exercises. Individuals performing upright, resisted, dynamic exercises can achieve high trunk muscle activation and thus may not need to add instability device exercises to augment core stability training.

In acute experiments on urethane-anaesthetized cats, motor responses of different parts of the colon (the proximal and descending parts as well the rectum) to microstimulation of neurons of the sacral parasympathetic nucleus (SPN) were investigated. The stimulation was carried out by rectangle pulses of current with intensity 100-1000 microA, pulse width 0.5 ms and frequency 10 Hz. It was shown that the microstimulation of the SPN neurons located within SI-SIII segments of spinal cord induced mainly the excitatory motor responses of all regions of the colon. However the most pronounced responses were obtained when the neurons of SII segments were stimulated. On the whole, the responses of rectum to stimulation were greater than responses of the proximal part of the colon. Our results suggest that the SPN neurons located within SII segments play the most important role in reflex control of colon motility.

Retrograde labeling with horseradish peroxidase conjugated to wheat germ agglutinin showed that the pubococcygeus muscles of the female rat are innervated by a population of motoneurons located in a column approximately 2 mm in length in the central region of lamina IX of the sixth lumbar-first sacral spinal cord segments. These neurons have a dendritic distribution that projects to the lateral, medial and ventral regions of the gray matter. Values for soma size, primary dendrite length and arborization area obtained from intact animals that were in diestrous-2, were significantly reduced following ovariectomy. After hormone priming of the ovariectomized animals with estradiol benzoate and progesterone, an additional injection of estradiol benzoate alone or followed by progesterone increased the labeled length of the primary dendrites distributed to the lateral, but not to the medial or ventral regions of the gray matter in the spinal cord. However, dendritic labeling was not significantly increased when only progesterone was additionally injected. It therefore seems that pubococcygeus muscle motoneurons of the female rat are sensitive to the effects of gonadal hormones.

Because the disc and facets work together to constrain spinal kinematics, changes in the instant axis of rotation associated with disc degeneration or disc replacement may adversely influence risk for facet overloading and arthritis. The relationships between L5/S1 segmental kinematics and facet forces are not well defined, since previous studies have separated investigations of spinal motion and facet force. The goal of this cadaveric biomechanical study was to report and correlate a measure of intervertebral kinematics (the centrode, or the path of the instant axis of rotation) and the facet forces at the L5/S1 motion segment while under a physiologic combination of compression and anterior shear loading. Twelve fresh-frozen human cadaveric L5/S1 joints (age range 50-64 years) were tested biomechanically under semi-constrained conditions by applying compression plus shear forces in several postures: neutral, and 3 degrees and 6 degrees of flexion, extension and lateral bending. The experimental boundary conditions imposed compression and shear representative of in vivo conditions during upright stance. The 3-D instantaneous axis of rotation (IAR) was calculated between two consecutive postures. The facet joint force was simultaneously measured using thin-film sensors placed between both facet surfaces. Variations of IAR location and facet force during motion were analyzed. During flexion and extension, the IAR was oriented laterally. The IAR intersection with the mid-sagittal plane moved cephalad relative to S1 endplate during flexion (P=0.010), and posterior during extension (P=0.001). The facet force did not correlate with posture (P=0.844). However, changes in the facet force between postures did correlate with IAR position: higher IAR's during flexion correlated with lower facet forces and vice versa (P=0.04). During lateral bending, the IAR was oblique relative to the main plane of motion and translated parallel to S1 endplate, toward the side of the bending. Overall, the facet force was increased on the ipsilateral side of bending (P=0.002). The IAR positions demonstrate that the L5 vertebral body primarily rotates forward during flexion (IAR close to vertebral body center) and rotates/translates backward during extension (IAR at or below the L5/S1 intervertebral disc). In lateral bending, the IAR obliquity demonstrated coupling with axial torsion due to resistance of the ipsilateral facet.

The aim of this study was to investigate whether it is possible to reduce a charge per pulse, which is needed for selective nerve stimulation. Simulation is performed using a two-part simulation model: a volume conductor model to calculate the electrical potential distribution inside a tripolar cuff electrode and a human fiber model to simulate the fiber response to simulation. Selective stimulation is obtained by anodal block. To obtain anodal block of large fibers, long square pulses (> 350 micros) with a relatively high currents (1-2.5 mA) are usually required. These pulses might not be safe for a long-term application because of a high charge per pulse. In this study, several pulse shapes are proposed that have less charge per pulse compared with the conventional square pulse and would therefore be safer in a chronic application. Compared with the conventional square pulse, it was possible to reduce the charge with all proposed pulse shapes, but the best results are obtained with a combination of a square depolarizing pulse and a blocking pulse. The charge per pulse was up to 32% less with that pulse shape than with a square pulse. Using a hyperpolarizing anodal prepulse preceding a square pulse, it was not possible to block nerve fibers in a whole nerve bundle and to obtain reduction of a charge per phase. Reduction of the charge could be achieved only with spatially selective blocking. The charge per phase was larger for the combination of a hyperpolarizing anodal prepulse and a two-step pulse than for the two-step pulse alone.

After chronic spinal injury, motoneurons spontaneously develop two persistent inward currents (PICs): a TTX-sensitive persistent sodium current (sodium PIC) and a nimodipine-sensitive persistent calcium current (calcium PIC). In the present paper, we examined how these PICs contributed to motoneuron firing. Adult rats were spinalized at the S(2) sacral level, and after 2 months intracellular recordings were made from sacrocaudal motoneurons in vitro. The PICs and repetitive firing were measured with slow triangular voltage and current ramps, respectively. The sodium PIC was examined after blocking the calcium PIC with nimodipine (20 microM; n = 12). It was always activated subthreshold, and during current ramps in nimodipine, it produced a sodium plateau that assisted in initiating and maintaining firing (self-sustained firing). The sodium PIC oscillated off and on during firing and helped initiate each spike, and near threshold this caused abnormally slow firing (2.82 +/- 1.21 Hz). A low dose of TTX (0.5 microM) blocked the sodium PIC, sodium plateau, and very slow firing prior to affecting the spike itself. The calcium PIC was estimated as the current blocked by nimodipine or current remaining in TTX (2 microM; n = 13). In 59% of motoneurons, the calcium PIC was activated subthreshold to firing and produced a plateau that assisted in initiating and sustaining firing because nimodipine significantly increased the firing threshold current and decreased the self-sustained firing. In the remaining motoneurons (41%), the calcium PIC was activated suprathreshold to firing and during current ramps did not initially affect firing but eventually was activated and caused an acceleration in firing followed by self-sustained firing, which were blocked by nimodipine. The frequency-current (F-I) slope was 3.0 +/- 1.0 Hz/nA before the calcium PIC activation (primary range), 6.3 +/- 3.6 Hz/nA during the calcium PIC onset (secondary range; acceleration), and 2.1 +/- 1.3 Hz/nA with the calcium PIC steadily activated (tertiary range). Nimodipine eliminated the secondary and tertiary ranges, leaving a linear F-I slope of 3.7 +/- 1.0 Hz/nA. A single low-threshold shock to the dorsal root evoked a many-second-long discharge, the counterpart of a muscle spasm in the awake chronic spinal rat. This long-lasting reflex was caused by the motoneuron PICs because when the activation of the voltage-dependent PICs was prevented by hyperpolarization, the same dorsal root stimulation only produced a brief excitatory postsynaptic potential (<1 s). Both the calcium and sodium PIC were involved because nimodipine only partly reduced the reflex and there remained very slow firing mediated by the sodium PIC.

The aim was to determine whether blockade of store-operated Ca(2+) entry, or inhibition of Ca(2+) sensitisation, is the predominant mechanism by which neuronally released nitric oxide mediates relaxation of the mouse anococcygeus. Nitrergic relaxations to field stimulation (10 Hz, 10 s trains) were unaffected by the sarcoplasmic reticulum Ca(2+) ATPase blocking agent thapsigargin (100 nM), known to prevent nitric-oxide-induced inhibition of store-operated Ca(2+) entry. Conversely, the myosin phosphatase inhibitor calyculin-A (1 microM) caused almost complete abolition of nitrergic relaxations. The results provide evidence that inhibition of Ca(2+) sensitisation is the major cellular mechanism underlying nitrergic relaxation of the mouse anococcygeus.

1. The effects of copper chelators were investigated on the relaxant actions of the S-nitrosothiols S-nitrosoglutathione (GSNO) and S-nitroso-N-acetyl-d,l-penicillamine (SNAP), the non-S-nitrosothiol nitric oxide (NO) donor sodium nitroprusside (SNP), free radical NO (NO.) and the nitrergic neurotransmitter in rat isolated anococcygeus muscle. 2. Cumulative additions of GSNO (0.01-100 micro mol/L), SNAP (0.001-10 micro mol/L), SNP (0.001-1 micro mol/L) and NO. (0.5-5 micro mol/L) and electrical field stimulation (EFS; 1-5 Hz, 10 s) of nitrergic nerves in preparations precontracted with guanethidine (10-30 micro mol/L) and clonidine (0.01-0.3 micro mol/L) produced concentration-dependent relaxations. 3. The Cu[I] chelator neocuproine (10-30 micro mol/L) produced concentration-dependent inhibitions of the relaxations to GSNO and SNAP. At 30 micro mol/L, neocuprinone had no effect on relaxations to SNP (0.001-1 micro mol/L), NO. (0.5-5 micro mol/L) or EFS (1-5 Hz, 10 s). 4. The Cu[II] chelator cuprizone (30 micro mol/L) slightly and significantly enhanced relaxations to GSNO and NO., but had no effect on relaxations to SNAP, SNP or EFS. 5. In conclusion, the results indicate that Cu[I], but not Cu[II], may be involved in the relaxant actions of GSNO and SNAP in the rat anococcygeus muscle.

The purpose of the present study was to characterize the transmitter content of structures in presynaptic apposition to the central terminals of cutaneous afferent fibers in the dorsal horn of the spinal cord. Axons in the Aalphabeta conduction velocity range were identified in adult cats, stained intra-axonally with horseradish peroxidase, and prepared for combined light and electron microscopy. In total, we labeled two slowly adapting (Type 1) axons, two hair-follicle afferents, and one rapidly adapting (Krause) afferent. Ninety-nine labeled boutons were examined through complete series of serial sections. Approximately 80% of boutons originating from rapidly adapting and hair-follicle afferents were postsynaptic to other axons, but only 50% of boutons from slowly adapting axons were associated with this type of arrangement. Postembedding immunogold reactions revealed that between 80% (for slowly adapting axons) and 100% (for rapidly adapting axons) of boutons presynaptic to primary afferents were immunoreactive for gamma-aminobutyric acid (GABA). The vast majority of these terminals (in excess of 80%) were also enriched with glycine. Therefore, presynaptic inhibition of these three functional classes of Aalphabeta cutaneous primary afferents is mediated principally by the subgroup of GABAergic interneuron that also contains glycine., (Copyright 2002 Wiley-Liss, Inc.)

The rhythmogenic capacity of the tail-innervating segments (L4-Co3) of the spinal cord was studied in isolated spinal cord and tail-spinal cord preparations of neonatal rats. Bath-applied serotonin/N-methyl-D-aspartate (NMDA) failed to produce a robust sacrococcygeal rhythmicity following midlumbar transection of the spinal cord. By contrast, a regular alternating left-right rhythm could be induced in the sacrococcygeal segments by application of noradrenaline (NA) or NA and NMDA before and after midlumbar transection of the cord. This rhythm was accelerated with the concentration of NMDA and was blocked by alpha1 or alpha2 adrenoceptor antagonists. The efferent bursts induced by NA/NMDA were accompanied by rhythmic tail movements produced by alternating activation of the left and right tail muscles and by coactivation of flexors, extensors, and abductors on a given side of the tail. This coactivation implies that reciprocal inhibitory pathways were not activated during the rhythm. Lesion experiments revealed that the rhythmogenic circuitry is distributed along all or most of the sacrococcygeal segments. The NA/NMDA-induced rhythm persisted in the isolated sacrococcygeal (S1-Co3), sacral (S1-S4), coccygeal (Co1-Co3), and smaller isolated regions of the sacrococcygeal cord. The rhythm also could be maintained in longitudinally split sacrococcygeal hemicords in which flexor, extensor, and abductor motoneurons are coactivated. This finding indicates that neither left/right nor flexor/extensor inhibitory interactions are required for rhythmogenesis in the sacrococcygeal cord. A slow rhythm lacking the alternating left-right pattern was induced by NA/NMDA in tail-innervating caudal lumbar segments of isolated L4-Co3 preparations. This rhythm was independent of the concurrent sacrococcygeal rhythm and the activity pattern of the tail musculature and it does not seem to contribute to rhythmic tail movements under these conditions. Comparative studies of the rhythm produced in the isolated caudal lumbar, sacrococcygeal cord, and caudal thoracic-rostral lumbar segments revealed that the S1-Co3 rhythm was faster than the L4-L6 pattern and slower than the T6-L3 rhythm. It is suggested that the caudal lumbar and sacrococcygeal segments of the cord are normally driven by the faster rostral lumbar central pattern generators. The relevance of the findings described above to pattern generation in the mammalian spinal cord is discussed.

Parasympathetic preganglionic neurons in the cat sacral spinal cord innervate intraspinal neurons and pelvic target organs. Retrograde tracing studies have revealed little of the morphology of their axons including their origin, initial segments, or their myelin, due to methodological limitations. Intracellular labeling of single neurons with neurobiotin or HRP has overcome these problems. Axons were studied in 24 preganglionic neurons. In 21 neurons the axon originated as a branch of a dendrite, without a detectable axon hillock, at distances from the soma ranging from 10 to 110 microm (average 34.1 microm ). In 3 neurons the axon was derived from the soma. Initial segments, present in all cells, ranged from 15 to 40 microm (average 26.8 microm). Nearly all axons followed the initial segment with unmyelinated segments that varied between 59 to 630 microm, followed by myelin and nodes of Ranvier. Internodal distances were variable and relatively short (average 93 microm). Axonal diameters measured over the intraspinal course in 18 axons averaged 1.3 microm (range 0.6-2.4 microm) and were relatively constant compared with other neurons. Spine-like protrusions were observed on the initial segments of 12 cells. Axon collaterals originated from unmyelinated sections and nodes of Ranvier. Antidromic action potentials showing initial segment, soma-dendritic inflections, did not differentiate between soma-derived and dendrite-derived axons. The data suggest that axons originating from a dendrite are the normal structure of preganglionic neurons in the lateral sacral parasympathetic nucleus. It is proposed that the particular structure of these axons may be part of a timing mechanism that coordinates preganglionic neurons with other spinal neurons involved in target organ reflexes.

We examined the ability of the isolated lumbosacral spinal cord of the neonatal mouse (P0-7) to generate rhythmic motor activity under several different conditions. In the absence of electrical or pharmacological stimulation, we recorded several patterns of spontaneous ventral root depolarization and discharge. Spontaneous, alternating discharge between contralateral ventral roots could occur two to three times over a 10-min interval. We also observed other patterns, including left-right synchrony and rhythmic activity restricted to one side of the cord. Trains of stimuli delivered to the lumbar/coccygeal dorsal roots or the sural nerve reliably evoked episodes of rhythmic activity. During these evoked episodes, rhythmic ventral root discharges could occur on one side of the cord or could alternate from side to side. Bath application of a combination of N-methyl-D,L-aspartate (NMA), serotonin, and dopamine produced rhythmic activity that could last for several hours. Under these conditions, the discharge recorded from the left and right L(1)-L(3) ventral roots alternated. In the L(4)-L(5) segments, the discharge had two peaks in each cycle, coincident with discharge of the ipsilateral and contralateral L(1)-L(3) roots. The L(6) ventral root discharge alternated with that recorded from the ipsilateral L(1)-L(3) roots. We established that the drug-induced rhythm was locomotor-like by recording an alternating pattern of discharge between ipsilateral flexor and extensor hindlimb muscle nerves. In addition, by recording simultaneously from ventral roots and muscle nerves, we established that ankle flexor discharge was in phase with ipsilateral L(1)/L(2) ventral root discharge, while extensor discharge was in phase with ipsilateral L(6) ventral root discharge. Rhythmic patterns of ventral root discharge were preserved following mid-sagittal section of the spinal cord, demonstrating that reciprocal inhibitory connections between the left and right sides of the cord are not essential for rhythmogenesis in the neonatal mouse cord. Blocking N-methyl-D-aspartate receptors, in both the intact and the hemisected preparation, revealed that these receptors contribute to but are not essential for rhythmogenesis. In contrast, the rhythm was abolished following blockade of kainate/AMPA receptors with 6-cyano-7-nitroquinoxalene-2,3-dione. These findings demonstrate that the isolated mouse spinal cord can produce a variety of coordinated activities, including locomotor-like activity. The ability to study these behaviors under a variety of different conditions offers promise for future studies of rhythmogenic mechanisms in this preparation.

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.

Electrical stimulation of the urethral sensory pudendal nerve in decerebrate or acute spinal cats was used to evoke micturition reflexes in animals that failed to respond to bladder distension. In the decerebrate animals, stimulation of urethral afferents evoked voiding characterized by a large bladder pressure increase coordinated with a simultaneous decrease in external urethral sphincter activity. In animals in which the spinal cord was transected between T10 and L6, electrical stimulation of the urethral afferents evoked small increases in bladder pressure that were insufficient to expel fluid but the contractions were coordinated with a decrease in external urethral sphincter activity. It was concluded that in addition to interacting with spinobulbospinal micturition pathways, urethral pudendal afferents may have direct access to a spinal circuitry that can coordinate bladder and sphincter activity.

The purpose of this study was to investigate the feasibility of selective detrusor activation without activation of the urethral sphincter by sacral root stimulation in patients. The sacral roots were stimulated using a tripolar electrode. An anodal block was used to prevent the urethral sphincter from contraction. Using square current pulses (700 microseconds, 6-7 mA), no increase in intraurethral pressure was measured, while a normal increase in intravesical pressure occurred. The minimum pulse duration to obtain a complete block was 550 microseconds. The study shows that anodal blocking of action potentials is possible in humans and can result in selective detrusor activation when used in sacral root stimulation.

Objective: To investigate the predictive value of sacral nervous function, result of pelvic examination and hormonal status on sexuality before and after subtotal hysterectomy., Material and Method: One hundred and four women were examined and interviewed one month before and one year after hysterectomy for non-malignant diseases. Genital examination, sacral nervous function testing including vibrotactility were performed, and sex hormone levels were estimated at each occasion. The results were evaluated and compared using multivariate analyses., Results: Postoperative experience of multiple orgasm was negatively correlated to three out of five measured factors for pelvic sacral function: i.e. vibrotactility of the clitoris, the external anal reflex and the levator muscle strength. No correlations were found between tests for sacral nervous function and a latent factor for sexuality before and after the operation. Preoperative uterine size did not show correlation to either preoperative or postoperative sexual parameters nor did uterine pain during vaginal examination. The preoperative sex hormone levels, and the result of histopathological examination showed no correlation to sexual variables., Conclusion: Preoperative somatic findings including sacral nervous function and pelvic muscular strength cannot be used as predictors for sexuality after subtotal hysterectomy.

The mechanism of canine penile erection was studied in 6 'chronic' and 15 'acute' male dogs by means of sacral root stimulation combined with pharmacologic studies. The basic mechanism of erection cannot be explained by a pure increase in arterial perfusion of the cavernous spaces due to neural vasomotor regulation. The vasomotor mechanism, whether pure arteriolar vasodilation, or venous drainage impairment, or secondary to as yet undefined behavior of the corporal smooth muscle, can be activated by stimulation of the parasympathetic outflow. Those preganglionic fibers may synapse to noncholinergic and non-beta-adrenergic neurons, which release a yet unidentified vasodilator neurotransmitter mediating the neurovascular effect.