[Rehabilitation after flexor tendon injuries of the hand]. / Rehabilitation nach Beugesehnenverletzungen an der Hand.

BACKGROUND: Advances in basic research evaluating suture material, techniques, and maximum tendon load with regard to repair site failure help to decide between rehabilitation protocols after the repair of flexor tendon injuries. OBJECTIVES: The presentation and choice of rehabilitation protocols depending on the mechanism of injury and knowledge of the influencing factors concerning tendon load. Expected outcome after flexor tendon repair. METHODS: Evaluating recent literature and basic research investigations, and presenting expert opinions. RESULTS: Based on the mechanism of injury, the suture technique, the compliance of the patient, and the latest knowledge on tendon capacity help to choose from the basic principles of rehabilitation protocols: passive or early motion protocols, such as those described by Duran-Houser and Kleinert, in the majority of cases lead to good and fair results according to the Hand Functional Score of the American Society for Surgery of the Hand. A larger number of excellent functional results are seen after the rehabilitation of flexor tendon injuries using combined passive/active or completely active motion protocols, e.g., according to Small. In addition to choosing a specific protocol and considering different zones of injury, it is essential to thoroughly supervise therapy and to monitor the adjustment of splints. It is widely recommended that patients should be provided with additional scar treatment and physical therapy throughout their entire rehabilitation. CONCLUSIONS: Flexor tendon injuries, especially in zone 2, are still a challenge with regard to operative treatment and rehabilitation, with an unpredictable outcome. Further knowledge and advances in suture techniques and material will support the use of active motion protocols and improve functional results in the future.

High-Pressure Bail-out Coronary Stenting Without Anticoagulation: Early Outcome and Follow-up Results.

PURPOSE:The purpose of this study is to assess the immediate outcome and long-term results of high pressure bail-out coronary stenting without subsequent anticoagulation. PATIENTS AND METHODS: Between June 1994 and September 1996, 32 consecutive patients (males 24, mean age 55 +/- 9.3 years) underwent bail-out stenting at a mean deployment pressure of 15.5 +/- 2.3 mmHg because of complicated PTCA. A total of 54 stents (Palmaz-Schatz, Micro, Gianturco Roubin and Wiktor) were implanted, from one to four stents into each vessel. After the procedure all patients were treated with ticlopidine 500 mg/day and acetylosalicylic acid 300 mg/day only. RESULTS: Stents were successfully delivered in all patients. In the cath lab procedural success was 96.9%. During the in-hospital phase, there was one (3.1%) acute stent thrombosis followed by urgent bypass surgery (CABG). Four (12.5%) non-Q wave myocardial infarctions occurred. There were no subacute stent thrombosis or hemorrhagic complications. Six month angiographic restudy in 28 patients showed restenosis in 13 (46.4%): 9 patients were treated successfully by rePTCA. At one year 13 (40.6%) major adverse cardiac events occurred: eleven (34.4%) target lesion revascularizations (9 PTCA, 2 CABG), one (3.1%) elective CABG surgery and one (3.1%) late cardiac death. Event-free survival was 93.8% at one month, 65.6% at six months, and 59.4% at one year. CONCLUSIONS: High pressure bail-out coronary stenting with antiplatelet regimen is an effective and safe procedure for treating complicated PTCA. Although the restenosis rate is high, in most cases in-stent restenosis can be treated by rePTCA. In 60% of patients clinical course at one year was uneventful.

Prolongation in expiration evoked from ventrolateral pons of adult rats.

Activation of neurons in the ventrolateral (vl) pons was hypothesized to alter the breathing pattern because previous studies demonstrated apneusis after inhibiting neuronal activity with bilateral muscimol (10 mM) microinjections into the vl pons (17). The excitatory amino acid L-glutamate (10 mM) was microinjected (10-100 nl) into the vl pons in anesthetized, vagotomized, paralyzed, and ventilated adult rats (n = 8). In four of these animals, the target site was approached from the ventral surface of the pons to avoid penetrating the dorsolateral (dl) pons. The expiratory phase was prolonged transiently and concurrently with the microinjection. The location of the injection sites included the A5 area, was independent of the approach, and was distinct from the dl pons. These results complement our previous data and indicate that neurons located in the vl pons influence respiration specifically by prolonging expiration when activated and by delaying the inspiratory-to-expiratory phase transition when inhibited.

[Early and long-term outcome after coronary artery patency]. / Wczesne I odlegle wyniki po udroznieniu tetnic wiencowych.

The role of percutaneous transluminal coronary angioplasty (PTCA) in the management of chronically occluded coronary arteries is still controversial. Percutaneous transluminal coronary angioplasty of chronic total occlusion is associated with relatively low success rates and a high incidence of restenosis. The purpose of this analysis was to determine, from the records of our institution, the efficacy and long-term outcome of angioplasty performed for chronic total occlusion defined as complete occlusion (Thrombolysis in Myocardial Infraction [TIMI] grade 0). PTCA was performed in 212 consecutive patients with chronically occluded coronary arteries and was successful in 125 (59%) patients. Complications were not observed. Successful initial PTCA was related to the clinical duration of occlusion and the type of guidewire (the primary success rate with the conventional guidewire was 49 (48%) versus 76 (69.1%) with Magnum Meier System p < 0.01). Repeat angiography was performed for 65 (52.0%) consecutive patients with successful initial PTCA and demonstrated restenosis in 34 (52.3%). 17 patients were successfully treated by a second PTCA. Restenosis or reocclusion was not clearly related to the residual stenosis post PTCA. In addition, the grade of collateral supply was not different in the vessels with and without restenosis.

Reversal of ischaemic systolic and diastolic left ventricular dysfunction by successful coronary angioplasty in patients with non-Q wave anterior myocardial infarction.

The effect of PTCA on global and regional left ventricular systolic function, isovolumic relaxation, chamber and muscle stiffness were studied in 30 patients with angina pectoris, previous non-Q wave anterior myocardial infarction (AMI) and significant stenosis of the left anterior descending coronary artery (LAD). In 11 of the 30 patients the condition was stable, but it was unstable in 19. Left ventricular angiograms were obtained before and 4.85 +/- 3.67 months after PTCA. The RAO was in the 30 degree projection, with the silhouette of the left ventricle sliced into 90 regions; changes in left ventricular volume, pressure and anterior wall thickness during the full cardiac cycle, together with dp/dt were demonstrated. After PTCA, global ejection fraction increased from 68.77 +/- 5.96% to 76.57 +/- 3.18%, P < 0.001. Impaired contractility was found in 29/90 (32.2%) regions before PTCA and in 5/90 (5.6%) after PTCA, P < 0.001. The time constant of the isovolumic pressure fall decreased after PTCA (52.56 +/- 17.40 ms vs 39.61 +/- 11.26 ms, P < 0.01). Elastic chamber stiffness coefficient decreased (0.022 +/- 0.003 vs 0.008 +/- 0.004, P < 0.001) and peak rate of left ventricular filling increased (319.0 +/- 107.9 ml.min-1 vs 396.8 +/- 201.4 ml.min-1, P < 0.05) after PTCA. The muscle stiffness coefficient was within normal values before and did not change after PTCA. The study findings show that in patients with persistent angina pectoris after non-Q wave AMI, complex systolic and diastolic ischaemic dysfunction occurs. This dysfunction can be reversed after successful PTCA of LAD.

A 'pneumotaxic centre' in rats.

Electrical and chemical lesions in the ventrolateral pons produced apneustic breathing in anesthetized, vagotomized, paralyzed, ventilated adult rats (n = 13). Apneustic breathing did not develop if the vagi remained intact and was reversed partially with vagal (proximal end) stimulation. Physiologically, these data are similar to those obtained following dorsolateral pontine lesion in rat and other mammalian species and support the hypothesis that pontine neurons influence breathing similarly across mammalian species.

[Long term observations of patients after percutaneous inferior vena cava filter placement for recurrent pulmonary embolism]. / Odlegle obserwacje chorych po przezskórnym zalozeniu filtru do zyly glównej dolnej z powodu nawracajacych zatorów plucnych.

Pulmonary embolism remains an important cause of mortality despite recent advances in medical therapy. The inferior vena cava filter has been devised for treatment of pulmonary embolism. The Gunter inferior vena cava filter was inserted percutaneously in 6 patients with recurrent pulmonary embolism despite anticoagulation therapy. No complications were observed during this procedure. Two patients died after filter placement (one after six weeks one after 1.5 year) because of right heart failure observed before procedure. The other four patients showed no signs of pulmonary embolism during four years follow-up. We conclude that percutaneous insertion of the Gunter filter is a safe and effective technique for prevention of recurrent pulmonary embolism.

[Coronary ultrasonography. More exact than coronary angiography? Description of two case histories]. / Ultrasonografia sródnaczyniowa tetnic wiencowych. Dokladniejsza niz koronarografia? Opis dwóch przypadków.

Coronary angiography as the "golden standard" in diagnostic imaging, guiding and assessing the results of interventional therapy has well known limitations inherent to the two dimensional imaging of three dimensional structures. Intravascular ultrasonography provides cross-sectional images of coronary artery, allowing an accurate calculation of cross-sectional luminal area and assessment of the degree of eccentricity of plaque and its structure including fissures, dissections and intracoronary thrombi. Case 1: Coronary angiography was performed in a 60 y. male patient with unstable angina revealing only a 40% stenosis in proximal LAD. The inconsistency of clinical presentation with angiography findings led to perform an intravascular ultrasound (IVUS) examination of LAD. The angiographic 40% stenosis was found to be over 80% on IVUS. Subsequent PTCA procedure led to a good IVUS and clinical result with no obvious changes in angiography. Case 2: PTCA of 80% Cx stenosis was performed with good immediate angiographic result, without dissection nor residual stenosis. However, IVUS immediately after PTCA assessed a dissection of the plaque with a flap protruding into the lumen. The patient was sent back to coronary angiography several hours later with clinical and ecg symptoms of acute myocardial ischemia. An important, occlusive dissection was found at the PTCA site. Angioplasty was performed again restoring a wide lumen at intervention site. IVUS was able to clarify the ambiguous angiographic findings with an important impact on interventional therapy. The immediate results of invasive procedures were readily and safely assessed by intravascular ultrasound.

[Treatment of 3 patients with arrhythmias using "radiofrequency" ablation]. / Leczenie 3 chorych z zaburzeniami rytmu serca metada "radiofrequency".

In 3 patients radiofrequency (RF) ablation of AV node (n = 2) and left sided accessory pathway (n = 1) was performed because of intractable tachyarrhythmias. RF ablation was made in the first patient (ablation of AV node) using 135 Watts during 72 sec., in the second patient (AV node ablation) 331 Watts during 185 sec., and in the last patient 883 Watts during 695 sec. In the last patient ablation of accessory pathway was unsuccessful and the patient has been successfully operated. AV conduction was interrupted in 2 cases. No complications were noted. General anesthesia was not required. All the patients were discharged in a good state.

[Complications of percutaneous transluminal coronary angioplasty (PTCA)]. / Powiklania zabiegów przezskórnej sródnaczyniowej koronaroplastyki (PTCA).

Between 1981 and 1990, 714 patients underwent 756 percutaneous transluminal coronary angioplasty (PTCA) procedures. A total of 52 patients (6.9%) had major in-hospital complications: 5 patients (0.66%) died, Q-wave or non Q-wave myocardial infarction were observed in 13 patients (1.66%) during procedure and in 8 (1%) outside the catheterization laboratory, before discharge. Because of periprocedural occlusion 11 patients (1.5%) were managed with bypass surgery, 8 (1%) had a transient occlusion that was reopened with PTCA. 21 patients (2.8%) were not ++re-dilated but managed pharmacologically. Dissection, intracoronary thrombus and previous thrombolytic treatment were often associated with occlusion. The risk of dissection was related to lesion morphology. Long-(more than 1 cm) lesion, eccentric stenosis and tortuosity of the vessel segment undergoing dilatation were risk factors for occlusive dissection. There was a high risk of side branch occlusion if its take-off was narrowed and side branch originated from the target lesion. One of the most important risk predictors is the amount of jeopardized myocardium supplied by the target coronary artery. Acute closure of an artery supplying large amount of myocardium may cause abrupt hemodynamic collapse. Hypotension secondary to the artery occlusion may cause a decrease of the flow in the other coronary arteries, leading to cardiogenic shock. Although it is important to note that patients with unstable angina, intracoronary thrombus, long and complex lesion, severe multivessel disease and compromised left ventricular function are at higher risk of acute complication, PTCA is a relatively safe procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

[Percutaneous transluminal coronary angioplasty in patients with high risk bypass surgery]. / Przezskórna angioplastyka wiencowa u chorych z wysokim ryzykiem leczenia operacyjnego.

The purpose of this study was to assess the immediate and long-term results of incomplete percutaneous transluminal coronary angioplasty (PTCA) in high-risk coronary artery bypass surgery (CABG) patients. 24 pts (male-22, female-2, age - 39-60 years) were divided into 2 groups: I-8 pts with unstable angina pectoris who were definitely not CABG candidates because of very low ejection fraction (LVEF < 24%) and/or diffuse coronary atherosclerosis; II-16 pts selected for CABG only after failed PTCA. From this group 12 pts with unstable angina pectoris and history of myocardial infarction were at higher CABG risk because of LVEF < 40% and diffuse coronary atherosclerosis. 4 pts were poor surgical candidates because of coexistent medical disorders. The strategy of PTCA was to dilate first the most critical (culprit) lesion, responsible for the patient symptoms, usually situated in the artery supplying large area of viable myocardium. We did not achieve: complete revascularization in all our pts (incomplete revascularization by intent). Initial success rate of the PTCA in both groups was 100%. There were no serious complications. During follow-up (6 months--4 yrs) long-term clinical improvement was observed in 7 pts from group I (87.5%) and 14 pts from group II (87.5%). We conclude, that in most pts with unstable angina pectoris and with high-risk of CABG good immediate and long-term results of incomplete PTCA can be achieved.

Morphometric analysis of phrenic motoneurons in the cat during postnatal development.

The dendritic geometry of 20 phrenic motoneurons from four postnatal ages (2 weeks, 1 and 2 months, and adult) was examined by using intracellular injection of horseradish peroxidase. The number of primary dendrites (approximately 11-12) remained constant throughout postnatal development. In general, postnatal growth of the dendrites resulted from an increase in the branching and in the length and diameter of segments at all orders of the dendritic tree. There was one exception. Between 2 weeks and 1 month, the maximum extent of the dendrites increased in parallel with the growth of the spinal cord; however, there was no increase in either combined dendritic length or total membrane surface area. In addition, there was a significant decrease in the number of dendritic terminals per cell (59.8 +/- 9.3 vs. 46.4 +/- 7.4 for 2 weeks and 1 month, respectively). The distance from the soma, where the peak number of dendritic terminals per cell occurred, ranged from 700-900 microns at 2 weeks and 2 months to 1,300-1,700 microns in the adult. The diameter of dendrites as a function of distance from the soma along the dendritic path increased with age. The process of maturation tended to increase the distance from the soma over which the surface area and dendritic trunk parameter (sigma d1.5/D1.5) remained constant. The three-dimensional distribution of dendrites was analyzed by dividing space into six equal volumes or hexants. This analysis revealed that the postnatal growth in surface area in the rostral and caudal hexants was proportionately larger than that in either the medial, lateral, dorsal, or ventral hexants. Strong linear correlations were found between the diameter of the primary dendrite and the combined length, surface area, volume, and number of terminals of the dendrite at all ages studied.

Electrophysiological properties of developing phrenic motoneurons in the cat.

1. Intracellular recordings were made in 427 phrenic motoneurons from kittens (in four stages of postnatal development, ranging from 2 to 14 wk) and in 72 motoneurons from adult cats. These experiments were performed to determine how the pattern of spontaneous discharge changes in phrenic motoneurons during development and how these changes might be influenced by alterations in the electrophysiological properties of these neurons. 2. The mean axonal conduction velocity increased significantly (P less than 0.0001) throughout this period of development, with the most rapid increase occurring between weeks 2 and 5 (18.5 +/- 5.4 and 32.4 +/- 5.6 m/s, respectively, mean +/- SD). 3. There was no change in the magnitude of the membrane potential, antidromic action potential, or positive overshoot; whereas there was a decrease in the half-width of the action potential from 2 (652 +/- 184 ms) to 14 (525 +/- 116 ms) wk postnatal. 4. The mean duration of the afterhyperpolarization (AHPdur) decreased from 69 +/- 20 ms at 2 wk to 60 +/- 16 ms by 9 wk, then increased to 66 +/- 18 ms by 14 wk of age and to 75 +/- 21 ms in the adult. The mean amplitude of the afterhyperpolarization (AHPamp) in the 2-wk-old group (4.9 +/- 1.8 mV) was larger than that at weeks 5 (3.9 +/- 1.7 mV) and 9 (3.9 +/- 1.6 mV), whereas the mean AHPamp of the adult (3.1 +/- 1.2 mV) was significantly smaller than the mean of any younger group. A significant negative correlation was found between AHPdur and axonal conduction velocity in all age groups studied, including the adult.(ABSTRACT TRUNCATED AT 250 WORDS)

[Complex angioplasty (PTCA) in the treatment of coronary artery stenosis]. / Kompleksowa koronaroplastyka (PTCA) w leczeniu kilku zwezen tetnic wiencowych.

56 patients with more than one stenotic coronary artery were treated by complex PTCA with success rate of 96.4%. Complications occurred in 3.6% of pts. Restenoses were found in 9.4% of pts; only one of the dilated arteries were restenosed. 11.3% of pts had repeated PTCA, because of progression of stenosis in other than previously treated artery. Angina occurred earlier in pts with restenoses than in pts with progression of stenoses. Late efficacy (mean 19 months) of complex PTCA was high (90.7%).

The activity pattern of phrenic motoneurons during the aspiration reflex: an intracellular study.

Membrane potential trajectories and discharge characteristics were measured intracellularly in 29 phrenic motoneurons of anesthesized, paralyzed and artificially ventilated cats during hypercapnic respiration and the aspiration reflex. Fifteen 'active' cells discharged spontaneously during inspiration, and the remaining 14 'quiescent' cells exhibited no discharge in spite of strong central respiratory drive. The mean membrane potential of the quiescent cells during inspiration (-62 +/- 4 mV) was significantly lower than the threshold level determined for the active cells -52 +/- 4 mV). The mean axonal conduction velocity was slower for the active (60.4 +/- 8.7 m/s) than quiescent cells (67.4 +/- 6.9 m/s). All phrenic motoneurons discharged during the aspiration reflex with maximum instantaneous frequencies ranging from 6 to 357 Hz. No differences were found for the maximum discharge frequency during the reflex between the active and quiescent cells. Although there were differences in the slopes of the depolarization during inspiration between the groups of cells, no such difference existed in the slopes during the aspiration reflex. The threshold level for the first spike during the reflex was the same as that during inspiration but the level for successive spikes became progressively less negative while spike amplitude decreased and duration increased. Stimulation of the nasopharynx to elicit the aspiration reflex was found to alter the timing of the subsequent respiratory cycles.

[Angioplasty in acute and chronic occlusion of the coronary arteries]. / Angioplastyka w ostrej i przewleklej niedroznosci tetnic wiencowych.

An attempt of mechanical restoration of coronary artery patency and its angioplasty was carried out in 37 patients including 9 with acute myocardial infarction within 5 hours after the onset of an angina pain. The procedure was effective in 17 patients (45.9%), including 6 with acute myocardial infarction (66.7%). Mean time of a coronary artery occlusion was 5.1 weeks in the group with a good result in comparison with 17.2 weeks in the group with the unsuccessful procedure. In patients in whom restoration of a coronary artery patency was carried out within up to 3 months after its occlusion the procedure was effective in 64 per cent of them. Effectiveness of restoration of a coronary artery patency and its dilatation depends on the time from its occlusion to the procedure. The early attempt of the restoration of a coronary artery patency is effective in the majority of patients. In cases of the unsuccessful recanalization of a coronary artery occluded for a short time the main limitation of the procedure effectiveness was the vessel anatomy. The follow-up of 17 patients after a successful procedure showed restenosis or reocclussion in 6 of them (35%). It was referred in 1 case to the patient in whom restoration of a vessel patency was carried out during acute myocardial infarction (17%), and in 5 others to patients with a chronic occlusion of a coronary artery (45.5%).

Repetitive firing properties of phrenic motoneurons in the cat.

1. Using both rectangular- and ramp-shaped intracellularly injected currents, the repetitive firing properties of 23 antidromically identified phrenic motoneurons were determined in anesthetized, paralyzed, and artificially ventilated cats during hypocapnic apnea. In response to rectangular depolarizing current injections, regular repetitive firing was observed in all cells. 2. At the beginning of a rectangular current pulse, the firing pattern was characterized by high frequency of firing that rapidly adapted to a much lower steady-state value. The relationship between the reciprocal of the first interspike interval (F1-2) and injected current was described by an initial linear portion of shallow slope, followed by a much steeper segment that smoothly reached a plateau value. The plateau value of F1-2 did not change with further increase in injected current. 3. The steady-state firing frequency versus injected current relationship was represented by a line of shallow slope over the entire range of injected currents. The slope of this line ranged between 1.1 and 4.5 Hz/nA. 4. A weaker correlation between minimal firing frequency for continuous activity and the reciprocal of the after hyperpolarization duration (1/AHPdur) was found for phrenic motoneurons than exists for lumbosacral motoneurons (26). Comparison of AHP shape at different levels of repetitive firing revealed that the slopes of the ascending portions of the AHP were similar except at the higher injected currents. Further, in the same cells during natural inspiratory activity the ascending part of the AHP was similar to that observed during current injection. 5. Depolarizing current ramps (approximately 1-s duration) were injected into 11 phrenic motoneurons. Instantaneous firing frequency was directly proportional to the intensity of the instantaneous injected current and independent of the rate of change of current for the range of ramp slopes tested (5-80 nA/s). Ramp-and-hold current injections were done in three motoneurons, and the peak instantaneous firing frequency showed little adaptation during the hold maneuver. 6. During hypocapnic apnea, we mimicked the expiratory-phase inhibition and inspiratory-phase excitation of phrenic motoneurons by injecting a 1-s depolarizing current ramp that was immediately preceded by a 1-s hyperpolarizing current ramp of the same absolute peak current intensity. Compared with the effects of positive current ramps alone the spike onsets during the negative-positive current ramp paradigm were either facilitated or retarded. Various ionic mechanisms are suggested for these effects as well as their function in determining the onset of firing during natur

Projections and terminations of single respiratory axons in the cervical spinal cord of cat.

Position, divergence, branching, and termination patterns of single, respiratory axons were studied in cat cervical spinal cord by injecting horseradish peroxidase (HRP) intra-axonally. We stained 12 axons which were characterized by their firing patterns and by electrical stimulation. Five axons discharged during inspiration (I); the remaining 7 discharged during expiration (E). No injected axon was evoked by stimulating ipsilateral phrenic nerve roots while 7 (4 I, 3 E) of 12 were excited at a short latency from stimulating at a medullary site (on the midline, 1-2 mm rostral to the obex, approximately 3 mm below the dorsal medullary surface) where many bulbospinal respiratory axons decussate. All injected stem axons were located in the ventral and ventrolateral funiculi, traversed in a rostrocaudal direction, and were stained for lengths ranging from 3.6 to 12.4 mm. Mean axonal diameter was 2.9 microns. In 6 axons (4 I, 2 E), 14 collaterals were stained: 1 on each E axon, 2 on one I axon, 3 each on 2 others and 4 on another I axon. Collaterals emerged perpendicularly from the descending stem axon and projected directly to the ventral horn. The average distance between neighboring collaterals was 1.0 mm (n = 7). Collaterals did not arborize until they were near or within the ventral horn. Both en passant and terminaux types of presynaptic boutons were found primarily within the rostrocaudal cylinder that defined the phrenic motor column. In addition, some boutons were located dorsomedial to the phrenic motor column. We conclude that I axons, presumably of medullary origin, have multiple collaterals which terminate primarily in the phrenic motor column. However, the same axon can have terminals in different regions of the ventral horn, which are known to contain dendrites of phrenic motoneurons.

Influences from laryngeal afferents on expiratory bulbospinal neurons and motoneurons.

The purpose of this study is to analyze the reflex effects of laryngeal afferent activation on respiratory patterns in anesthetized, vagotomized, paralyzed, ventilated cats. We recorded simultaneously from the phrenic nerve, T10 internal intercostal nerve, and single bulbospinal expiratory neurons of the caudal ventral respiratory group (VRG). Laryngeal afferents were activated by electrical stimulation of the superior laryngeal nerve (SLN) or by cold-water infusion into the larynx. Both types of stimuli caused inhibition of phrenic activity and facilitation of internal intercostal nerve activity, indicating expiratory effort. The activity of 46 bulbospinal expiratory cells was depressed during SLN electrical stimulation, and 13 of them were completely inhibited. In 44 of 56 neurons tested, mean firing frequency (FFmean) was decreased in response to cold-water infusion and 8 others responded with increased FFmean; in the remaining 4 neurons, FFmean was unchanged. Possible reasons for different neuronal responses to SLN electrical stimulation and water infusion are discussed. We conclude that bulbospinal expiratory neurons of VRG were not the source of the reflex motoneuronal expiratory-like activity produced by SLN stimulation. Other, not yet identified inputs to spinal expiratory motoneurons are activated during this experimental condition.