Clinical analysis of two-level compression of the cauda equina and the nerve roots in lumbar spinal canal stenosis

STUDY DESIGN: This study is a prospective, clinical study assessing the efficacy of selective decompression of the responsible level in two-level stenosis in accordance with neurologic findings defined by the gait load test, and functional diagnosis based on selective nerve root block. OBJECTIVE: To clarify the clinical features of two-level stenosis regarding the neurologic level responsible for the symptoms, neurogenic intermittent claudication, and the outcome of selective decompression. SUMMARY OF BACKGROUND DATA: Experimental studies have indicated that double-level compression of the cauda equina induces a more severe impairment of nerve function than does single-level compression. However, few studies have focused on the clinical importance of two-level stenosis. The clinical effects of two-level stenosis on the cauda equina and nerve roots are unknown. METHODS: A total of 81 patients with lumbar spinal canal stenosis due to spondylosis and degenerative spondylolisthesis were divided into two groups, two-level stenosis at L3-L4 and L4-L5, and one-level stenosis at L4-L5, based on myelography. The types of neurogenic intermittent claudication, the level responsible for neurologic findings, and the postsurgical outcome were compared between both groups. The level responsible for the symptoms in two-level stenosis was determined in accordance with neurologic findings on the gait load test and functional diagnosis based on a selective nerve root block. All patients underwent a prospective, selective decompression at the neurologically responsible level only. The average follow-up period was 4.6 years (range, 1-8 years). RESULTS: The patients with two-level stenosis more frequently had cauda equina symptoms than those with one-level stenosis, except patients with degenerative spondylolisthesis. It was therefore assumed that two-level stenosis was associated with cauda equina impairment, Changes in neurologic condition before and after the gait test were observed in four patients with two-level stenosis. Finally, for 28 patients with two-level stenosis, the levels responsible for the neurologic symptoms were the caudal level (L4-L5) in 22 patients, the cranial level (L3-L4) in 1 patient, and both cranial and caudal levels (L3-L4 and L4-L5) in 5 patients. All stenotic levels on the myelogram were not always symptomatic in two-level stenosis. However, in one-level stenosis, all of the responsible levels completely corresponded to the myelogram. Selective decompression only at the neurologically responsible level improved neurogenic intermittent claudication in all patients. The asymptomatic levels at which the stenotic condition was left unchanged at surgery did not become symptomatic at follow-up; in addition, there was no significant difference in the postoperative outcome between two-level stenosis and one-level stenosis. CONCLUSIONS: Two-level stenosis in patients with lumbar spondylosis is associated with production of cauda equina lesions. The gait load test provides information regarding changes in symptoms and neurologic condition during exercise. The responsible levels should be determined based on neurologic findings after the gait load test and a selective nerve root block. It is uncommon for both stenotic levels to be symptomatic in patients with two-level stenosis. Less invasive surgery such as selective decompression for the responsible level in patients with two-level stenosis is a useful technique with a good potential for long-term success.     

Communication between the left ventricle and the right atrium in infectious endocarditis. Diagnosis using Doppler-echocardiography

OBJECTIVE: To examine regional distribution of blood flow in the brain of horses at rest and during exercise. ANIMALS: 9 clinically normal horses. PROCEDURE: Regional brain blood flow was measured using radionuclide-labeled 15-microns-diameter microspheres injected into the left ventricle, while reference blood samples were obtained from the aorta. RESULTS: At rest, cerebral cortex and caudate nuclei received significantly higher blood flow, compared with cerebral white matter. A similar perfusion heterogeneity existed in the cerebellum. In the brain stem, a gradual tapering of blood flow from thalamus-hypothalamus towards medulla was observed in standing horses. Progressive significant increases in heart rate and in aortic and right atrial pressures occurred during exercise at 8 and 13 m/s, and horses developed significant arterial hypoxemia and hypercapnia. Cerebral and cerebellar gray- to white-matter perfusion heterogeneity was maintained during exercise, indicating differential metabolic O2 needs. Despite arterial hypoxemia, hypercapnia, and hypertension, exercise did not result in significant changes in blood flow to the cerebral cortex and caudate nuclei whereas, in cerebral white matter, a significant decrease in blood flow was observed. In all cerebral tissues, vascular resistance increased during exercise, indicating autoregulation of cerebral blood flow. In the cerebellar cortex, blood flow increased significantly with strenuous exercise as vasodilation occurred. Vascular resistance in cerebellar white matter increased during exercise at 13 m/s. Blood flow in the medulla, pons, midbrain, and thalamus-hypothalamus was not significantly altered during exercise from that at rest. CONCLUSION: Despite arterial hypoxemia, hypercapnia, and hypertension, autoregulation of cerebral and cerebellar blood flow is maintained in horses during exercise.     

Lumbar spine stenosis: a common cause of back and leg pain

Lumbar spine stenosis most commonly affects the middle-aged and elderly population. Entrapment of the cauda equina roots by hypertrophy of the osseous and soft tissue structures surrounding the lumbar spinal canal is often associated with incapacitating pain in the back and lower extremities, difficulty ambulating, leg paresthesias and weakness and, in severe cases, bowel or bladder disturbances. The characteristic syndrome associated with lumbar stenosis is termed neurogenic intermittent claudication. This condition must be differentiated from true claudication, which is caused by atherosclerosis of the pelvofemoral vessels. Although many conditions may be associated with lumbar canal stenosis, most cases are idiopathic. Imaging of the lumbar spine performed with computed tomography or magnetic resonance imaging often demonstrates narrowing of the lumbar canal with compression of the cauda equina nerve roots by thickened posterior vertebral elements, facet joints, marginal osteophytes or soft tissue structures such as the ligamentum flavum or herniated discs. Treatment for symptomatic lumbar stenosis is usually surgical decompression. Medical treatment alternatives, such as bed rest, pain management and physical therapy, should be reserved for use in debilitated patients or patients whose surgical risk is prohibitive as a result of concomitant medical conditions.     

Occult lumbar lateral spinal stenosis in neural foramina subjected to physiologic loading

PURPOSE: To measure the effect of extension, flexion, lateral bending, and axial rotation loads applied to the spine on the anatomic relationship of the spinal nerves in the neural foramen to the ligamentum flavum and the intervertebral disk, anc to determine the effect of disk degeneration on the response to loading. METHODS: Cadaveric lumbar motion segments were examined with CT and MR imaging, loaded with pure moment forces, frozen in situ, reexamined with CT, and sectioned with a cryomicrotome. The morphology of the intervertebral disks was classified on the basis of the appearance of the cryomicrotome sections. The neural foramina were classified as having no evident stenosis, as being stenotic, as having occult stenosis, or as showing resolved stenosis on the basis of the images and sections before and after loading. The stenotic and nonstenotic foramina were stratified by disk level, intervertebral disk classification, and type of loading applied. The effect of spinal level, disk type, and load type on the prevalence of stenosis was studied. RESULTS: On average, extension, flexion, lateral bending, and axial rotation resulted in the ligamentum flavum or intervertebral disk contacting or compressing the spinal nerve in 18% of the neural foramina. Extension loading produced the most cases of nerve root contact, and lateral bending produced the fewest cases. Each of the loading types resulted also in diminished contact between the spinal nerve and the intervertebral disk or ligamentum flavum in some cases. Disk degeneration significantly increased the prevalence of spinal stenosis. All foramina associated with advanced disk degeneration and half of the foramina associated with disks having radial tears of the annulus fibrosus either developed occult stenosis or were stenotic before loading. CONCLUSIONS: The study supports the concept of dynamic spinal stenosis; that is, intermittent stenosis of the neural foramina. Flexion, extension, lateral bending, and axial rotation significantly changed the anatomic relationships of the ligamentum flavum and intervertebral disk to the spinal nerve roots.     

Dynamic effects on the lumbar spinal canal: axially loaded CT-myelography and MRI in patients with sciatica and/or neurogenic claudication

STUDY DESIGN: In patients with sciatica or neurogenic claudication, the structures in and adjacent to the lumbar spinal canal were observed by computed tomographic myelography or magnetic resonance imaging in psoas-relaxed position and during axial compression in slight extension of the lumbar spine. OBJECTIVES: To determine the mechanical effects on the lumbar spinal canal in a simulated upright position. SUMMARY OF BACKGROUND DATA: For years, functional myelographic investigation techniques were shown to be of value in the evaluation of suspected encroachment of the spinal canal. Since the advent of computed tomography and magnetic resonance imaging, there have been few clinical and experimental attempts that have imitated these techniques. The data indicate that the space within the canal is posture dependent. METHODS: Portable devices for axial loading of the lumbar spine in computed tomographic and magnetic resonance examinations were developed. Fifty patients (94 sites) were studied with computed tomographic myelography, and 34 patients (80 sites) with magnetic resonance in psoas-relaxed position followed by axial compression in slight extension. The dural sac cross-sectional area at L2 to S1, the deformation of the dural sac and the nerve roots, and the changes of the tissues surrounding the canal were observed. RESULTS: In 66 of the investigated 84 patients, there was a statistically significant reduction of the dural sac cross-sectional area in at least one site during axial compression in slight extension. Of the investigated patients, 29 passed the borderlines for relative (100 mm2) or absolute stenosis (75 mm2) in 40 sites. In 30 patients, there was deformation of the dural sac in 46 sites. In 11 of the patients investigated with magnetic resonance imaging, there was a narrowing of the lateral recess in 13 sites, during axial compression in slight extension. CONCLUSIONS: Axial loading of the lumbar spine in computed tomographic scanning and magnetic resonance imaging is recommended in patients with sciatica or neurogenic claudication when the dural sac cross-sectional area at any disc location is below 130 mm2 in conventional psoas-relaxed position and when there is a suspected narrowing of the dural sac or the nerve roots, especially in the ventrolateral part of the spinal canal in psoas-relaxed position. The diagnostic specificity of the spinal stenosis will increase considerably when the patient is subjected to an axial load.     

Functional assessment of coronary-artery stenosis (author's transl)

Left-ventricular angiography was performed in 28 patients after measuring ascending aortic and left ventricular pressures and during isometric exercise (hand grip, 0.3-0.4 kg/cm2 for 3 min). In 13 patients coronary blood flow was measured at rest and during hand-grip exercise by means of the argon method. Eight patients without heart disease served as controls. In 14 patients with coronary heart disease abnormal left-ventricular kinetics, demonstrated already at rest, got worse during hand-grip exercise. In five patients with normal left-ventricular angiograms at rest hypokinesia and dyskinesia occurred during isometric exercise. The coronary artery supplying the abnormal ventricular wall had a 50-75% decrease in diameter. One patients with isolated 25% stenosis had normal left-ventricular kinetics both at rest and on hand-grip exercise. In all patients coronary blood flow rose by 60-90% during isometric exercise. It iducing a significant rise in myocardial oxygen demand and increased coronary blood flow.     

Neuropathic pain in rats is associated with altered nitric oxide synthase activity in neural tissue

Peripheral nerve injury may lead to a chronic neuropathic pain state that results from an increase in excitability of central neurons. This central sensitization is mediated via an N-methyl-D-aspartic acid (NMDA) receptor and may involve the production of nitric oxide (NO). As NO is suggested to play a role in nociceptive transmission following nerve injury, we examined for altered NO synthase activity at multiple levels of peripheral and spinal neural tissue in a rat model of neuropathic pain. Peripheral neuropathy was induced in rats (N = 12) by ligation of the left L5 and L6 nerve roots. Six other rats had sham surgery. An ipsilateral decrease in paw withdrawal threshold to mechanical stimuli confirmed the presence of a neuropathic pain state. Samples of the lumbar and thoracic spinal cords, L4, L5, and L6 dorsal root ganglia (DRGs), and the sciatic nerves were obtained from the lesioned and contralateral sides at 2 and 4 weeks after neuropathic surgery (N = 6 per group). In the lumbar spinal cord, a bilateral decrease in nitric oxide synthase (NOS) activity was observed 2 and 4 weeks after neuropathic surgery. NOS activity was increased in the ipsilateral L5 and 6 DRGs 2 weeks following neuropathic surgery. An increase in NOS activity in the DRG may be an early mechanism for inducing more central changes. The bilaterally decreased NOS activity in the lumbar spinal cord may be secondary to a negative feedback mechanism resulting from increased NO production in the spinal dorsal root ganglia. Multiple alterations in expression of NOS activity that occur in both peripheral and central processing may play a role in the pain behavior resulting from peripheral nerve injury. (Preliminary results of these studies have been presented in abstract form at the annual meetings of the Society for Neuroscience, 1994, and the American Society of Anesthesiologists, 1994).     

Renal and intrarenal blood flow distribution in swine during severe exercise

It is known that a compensatory reduction and diversion of renal flow occurs in severe exercise in humans but not in dogs. We investigated this in miniature swine by measuring changes in total renal blood flow (TRF) and intra-renal blood flow (IRBF) distribution with tracer microspheres (15 +/- 5 mum) at rest and during steady-state exercise at 4.8-7.2 kph and 0% grade, and during severe exercise at 4.8-7.2 kph and 10% grade. We measured heart rate and cardiac output (Q) via implanted probes. TRF was determined as a percent of Q and as ml/100 g per min. IRBF was determined for the outer cortex, inner cortex, outer medulla, and inner medulla. Our results show that renal blood flow is significantly (P less than 0.05) reduced in pigs with exercise. Steady-state exercise reduced flow to about 66% of control and severe exercise reduced renal flow to 30% of control. IRBF was unchanged throughout. These results show that the exercising pig augments blood flow to skeletal muscle by reducing blood flow to kidneys, a response known to occur in man.     

Computer analysis system of blood oxygen saturation in an animal hypoxia model

Forearm blood flow (ml/min/100 ml) was determined with strain-gauge venous occlusion plethysmography at rest and in response to handgrip exercise in 7 patients with congestive heart failure and in 9 normal subjects before and after regional administration of endothelin-1 in the brachial artery. Administration of endothelin-1 significantly decreased forearm blood flow at rest and during exercise in normal subjects but did not change it at rest or during exercise in patients with congestive heart failure.     

Stenosis of the lumber spine. Clinical picture, diagnosis, treatment (author's transl)

Disc herniation is the most common reason for sciatica followed by osseous entrapment syndromes of the cauda equina. The osseous entrapment of nervous structures is possible within 3 segments of the spinal canal, the center, the recess and the intervertebral foramen. In all cases there is a disproportion of the size of the nervous structures and osseous gliding space. Central lumbar spinal stenosis is associated in 70% with limping (neurogenic claudication) which is often misinterpreted as vascular claudication. Clinic, diagnosis, therapy of lumbar spinal stenosis is described.     

Skeletal muscle blood flow in humans and its regulation during exercise

Regional limb blood flow has been measured with dilution techniques (cardio-green or thermodilution) and ultrasound Doppler. When applied to the femoral artery and vein at rest and during dynamical exercise these methods give similar reproducible results. The blood flow in the femoral artery is approximately 0.3 L min(-1) at rest and increases linearly with dynamical knee-extensor exercise as a function of the power output to 6-10 L min[-1] (Q= 1.94 + 0.07 load). Considering the size of the knee-extensor muscles, perfusion during peak effort may amount to 2-3 L kg(-1) min(-1), i.e. approximately 100-fold elevation from rest. The onset of hyperaemia is very fast at the start of exercise with T 1/2 of 2-10 s related to the power output with the muscle pump bringing about the very first increase in blood flow. A steady level is reached within approximately 10-150 s of exercise. At all exercise intensities the blood flow fluctuates primarily due to the variation in intramuscular pressure, resulting in a phase shift with the pulse pressure as a superimposed minor influence. Among the many vasoactive compounds likely to contribute to the vasodilation after the first contraction adenosine is a primary candidate as it can be demonstrated to (1) cause a change in limb blood flow when infused i.a., that is similar in time and magnitude as observed in exercise, and (2) become elevated in the interstitial space (microdialysis technique) during exercise to levels inducing vasodilation. NO appears less likely since NOS blockade with L-NMMA causing a reduced blood flow at rest and during recovery, it has no effect during exercise. Muscle contraction causes with some delay (60 s) an elevation in muscle sympathetic nerve activity (MSNA), related to the exercise intensity. The compounds produced in the contracting muscle activating the group IIl-IV sensory nerves (the muscle reflex) are unknown. In small muscle group exercise an elevation in MSNA may not cause vasoconstriction (functional sympatholysis). The mechanism for functional sympatholysis is still unknown. However, when engaging a large fraction of the muscle mass more intensely during exercise, the MSNA has an important functional role in maintaining blood pressure by limiting blood flow also to exercising muscles.     

L5 root compression caused by degenerative spinal stenosis of the L1-L2 and L2-L3 spaces

STUDY DESIGN: A severe bilateral L5 root lesion associated with spinal stenosis at L1-L2 and L2-L3 is described. OBJECTIVE: To describe clinical findings and the difficulty in obtaining a correct diagnosis of L5 Root Compression. SUMMARY OF BACKGROUND DATA: The disorder reported in this study has not been reported previously. Only one similar case has been described in the literature: an L5 root compression at L1-L2 caused by disc herniation. METHODS: Diagnosis was obtained by using computed tomography scanning, magnetic resonance imaging, and computed tomography myelography. The findings at L5-S1 were minimal to justify the patient's clinical symptoms, but a detailed study of the upper levels revealed spinal stenosis at L1-L2 and L2-L3, which could have been causing L5 and S1 root compression. A decompressive laminectomy and partial facetectomy in both levels were performed. RESULTS: The patient's pain and claudication disappeared, and clinical symptoms associated with the right L5 root improved. The left L5 root deficit remained stable. CONCLUSION: An unusual case of L5 root compression caused by degenerative stenosis of L1-L2 and L2-L3 is described.     

Innervation of the lumbar facet joints. Origins and functions

STUDY DESIGN: The levels of dorsal root ganglia and paravertebral sympathetic ganglia innervating the lumbar facet joint were investigated in rats using the retrograde transport method. The pathways and functions of the nerve fibers supplying the lumbar facet joint were determined immunohistochemically. OBJECTIVES: To study lumbar facet pain in relation to its innervation. SUMMARY OF BACKGROUND DATA: The lumbar facet joints have been reported to be innervated segmentally. Little is known, however, about the origins and functions of the nerve fibers. METHODS: Cholera toxin B subunit, a neural tracer, was placed in the L5-L6 facet joint, and the bilateral dorsal root ganglia and paravertebral sympathetic ganglia were examined immunohistochemically. The serial sections of lumbar vertebrae of newborn rats and the sections of the facet joint capsules, dorsal root ganglia, and paravertebral sympathetic ganglia of adult rats were investigated immunohistochemically. The pathways of the nerve fibers supplying the facet joint were reconstituted. RESULTS: Labeled neurons existed in ipsilateral dorsal root ganglia from L1 to L5 and in paravertebral sympathetic ganglia from T12 to L6. The dorsal ramus of the spinal nerve and rami communicantes were connected to each other by calcitonin gene-related peptide immunoreactive fibers and dopamine beta-hydroxylase immunoreactive fibers. CONCLUSIONS: The L5-L6 facet joint was innervated by ipsilateral dorsal root ganglia and paravertebral sympathetic ganglia, segmentally and nonsegmentally. Some of the sensory fibers from the facet joint may pass through the paravertebral sympathetic trunk, reaching L1 and/or L2 dorsal root ganglia. Inguinal and/or anterior thigh pain with lower lumbar facet joint lesions may be explained as referred pain.     

A prospective and consecutive study of surgically treated lumbar spinal stenosis. Part I: Clinical features related to radiographic findings

STUDY DESIGN: A prospective and consecutive study of surgical results obtained during serial follow-up investigations in patients who underwent surgery for central lumbar spinal stenosis. OBJECTIVES: To evaluate the result after surgical decompression for lumbar spinal stenosis, at regular intervals after surgery, and to correlate these results with values for preoperative parameters; special interest was focused on the results in relation to the degree of constriction of the spinal canal. SUMMARY OF BACKGROUND DATA: The outcome after surgery for spinal stenosis is debatable; long-term follow-up investigations have indicated deterioration with passing time. Results of studies in nonsurgical patients have demonstrated that the symptoms do not progress with time. Results of a meta-analysis of the literature on surgical results have demonstrated a wide variation of outcomes. MATERIAL AND METHODS: In a prospective study, 105 consecutive patients who underwent surgical decompression (laminectomy with facet-preserving technique, but no fusion) were evaluated at follow-up examinations 4 months and 1, 2, and 5 years after surgery. At the follow-up examinations, the patient's opinion on the surgical result was registered, using a four-grade scale. The occurrence of pain at rest and at night was registered, as well as the patient's walking ability. Statistical analysis was performed, relating the surgical results to patient age, gender, preoperative duration of symptoms and radiographically observed constriction as described in Part I of this study. The radiologist was blinded to patient outcome. Logistic regression analysis was performed. RESULTS: During the follow-up period, 19 patients underwent reoperation, consisting of fusion to treat lumbar pain (n = 4), repeat decompression because of progressive stenosis (n = 13), and repairs in response to surgical complications (n = 2). Follow-up results: The result, related to the recurrence of leg symptoms, deteriorated with passing time. Excellent results were reported by 63% to 67% at 4-month and 2-year follow-ups compared with 52% at the 5-year follow-up. There was a correlation between the constriction of the spinal canal and the outcome at all intervals. Patients with an anteroposterior diameter of 6 mm or less at the narrowest site had significantly better results. The logistic regression analysis demonstrated a significant correlation between a severe reduction of the anteroposterior diameter and excellent results and a tendency toward better results in patients with a shorter preoperative duration of symptoms. Improvement of walking ability was also associated with a pronounced constriction of the spinal canal. CONCLUSION: The results after surgical decompression in patients with central spinal stenosis deteriorated with time. There was a significant correlation between good result and pronounced constriction of the spinal canal. Patients with a preoperative duration of symptoms of less than 4 years and patients with no preoperative back pain tended to have better surgical outcomes. The reoperation rate was 18% within 5 years. When surgery for spinal stenosis is contemplated, these prognostic factors should be taken into consideration: The "ideal patient" has a pronounced constriction of the spinal canal, insignificant lower back pain, no concomitant disease affecting walking ability, and a symptom duration of less than 4 years.     

Rat liver transport and biotransformation of a cytostatic complex of bis-cholylglycinate and platinum (II)

Dobutamine is used as an alternative to exercise in conjunction with 99mTc-sestamibi SPECT perfusion imaging for detection of coronary artery disease. However, the use of quantitative dobutamine 99mTc-sestamibi SPECT imaging for enhanced detection of coronary stenosis has not been established. The goal of this study is to examine the effects of dobutamine stress on regional myocardial blood flow and relative myocardial 99mTc-sestamibi activity in the presence of a single-vessel stenosis. METHODS: In six open-chest dogs with left circumflex artery stenosis, radiolabeled microspheres were injected during baseline, severe stenosis and peak dobutamine stress (10 microg/kg/min). Technetium-99m-sestamibi was injected intravenously at peak dobutamine. Hearts were excised 20 min after 99mTc-sestamibi injection for SPECT imaging and post-mortem gamma-well counting. RESULTS: Dobutamine significantly increased heart rate, rate-pressure product and the first derivative of left ventricular pressure. Ischemic zone (left circumflex) myocardial blood flows (in ml/min/g) were: baseline, 0.92 +/- 0.15; stenosis, 0.65 +/- 0.16; and dobutamine, 1.19 +/- 0.38. Nonischemic zone myocardial blood flows were: baseline, 0.99 +/- 0.18; stenosis, 1.01 +/- 0.12; and dobutamine, 1.94 +/- 0.32 (p < 0.01 versus stenosis). Ischemic flows, expressed as percentages of nonischemic flows, were: baseline, 94% +/- 2%; stenosis, 63% +/- 11% (p < 0.05 versus baseline) and dobutamine, 60% +/- 12% (p was not significant versus stenosis). Technetium-99m-sestamibi activity in the ischemic zone (75% +/- 6% nonischemic) underestimated the relative flow deficit produced during dobutamine stress (p = 0.056). Myocardial 99mTc-sestamibi activity correlated with flow when flow was less than 1.0 ml/min/g. At higher flow ranges (1.0 ml/min/g-3.5 ml/min/g), 99mTc-sestamibi did not track flow. CONCLUSION: In a canine model of flow-limiting, single-vessel stenosis, dobutamine (10 microg/kg/min) did not augment flow heterogeneity. In addition, relative myocardial 99mTc-sestamibi activity underestimated microsphere flow at higher flows induced by dobutamine, leading to underestimation of ischemia. These findings suggest that dobutamine stress 99mTc-sestamibi scintigraphy may underestimate the relative flow deficit.     

Blood flow in different adipose tissue depots during prolonged exercise in dogs

Adipose tissue blood flow was measured by the microsphere technique in all major adipose tissue depots in dogs during exercise. The measurements were done during rest, after 1 and 2 h of exercise and after a postexercise rest period. It was found that the blood flow to the inguinal, subcutaneous adipose tissue increased from about 6 ml/(100 g . min) during rest to about 10 ml/(100 g.min) during exercise. This increase in flow was significantly smaller than the increase found in the perirenal, the mesenteric and the pericardial depots. In these depots the resting blood flow was about 10 ml/(100 g . min) increasing to about 30 ml/(100 g . min) during exercise. It is concluded that the increase in adipose tissue blood flow during exercise is a general phenomenon for all major adipose tissue depots. The increase in flow in the inguinal, subcutaneous fat pad was comparable to the previously described increase in flow in abdominal, subcutaneous tissue in man. Blood flow to abdominal skin was constant during exercise, while the flow in tissues from the gastrointestinal canal and in the kidneys decreased. The flow in the tongue and in the Achilles tendon significantly increased during exercise.     

Reduction by indobufen of neutrophil activation in peripheral arterial occlusive disease

We evaluated the effectiveness of indobufen administration in reducing neutrophil activation in a clinical model of ischemia-reperfusion. Thirty stable patients with intermittent claudication due to occlusive peripheral arterial disease of the leg were randomly assigned to two groups. Patients in group I were treated with indobufen [200 mg orally twice daily (p.o. b.i.d.) for a week]; patients in group II received a placebo. Both groups of patients were submitted to standardized treadmill exercise until onset of claudication. Plasma levels of thromboxane B2 (TxB2) and 6-keto-prostaglandin F1alpha(6-k-PGF1alpha) neutrophil filterability, and neutrophil activation (by nitro-blue tetrazolium test) were assessed in blood samples from the femoral vein draining the ischemic leg. The values were obtained at rest and 5, 30, and 60 min after onset of claudication. Urinary albumin excretion was measured at rest and 1 h after onset of claudication. Plasma levels of TxB2 and 6-k-PGF1alpha increased significantly in the placebo group 5 min after onset of claudication, whereas only a slight nonsignificant increase was observed in the indobufen-treated group at the same timepoint.     

Spinal tumour due to primary hyperparathyroidism causing sciatica: case report

We report a unilateral intraspinal cyst-like lesion adjacent to the lamina and facet joint at the L4-L5 level producing sciatica. Histological examination revealed multinucleate giant cells suggesting a brown tumour. Further studies disclosed primary hyperparathyroidism, whose first manifestation was the lumbar nerve root compression. Previous cases of compression of neural structures by spinal brown tumours are reviewed and a radiological differential diagnosis is presented.     

Myocardial blood flow distribution in miniature pigs during exercise

Total and regional myocardial blood flow was measured in miniature pigs at rest and during two levels of treadmill exercise, including maximal exercise. Exercise increased the myocardial blood flow in a linear manner with heart rate (r = 0.87). At rest the endocardial/epicardial blood flow ratio was significantly greater than unity with flow favoring the endocardium. Exercise failed to appreciably alter the distribution of coronary blood flow. Thus the myocardium was capable of further dilatation and perfusion of blood without compromising endocardial flow even during the most severe level of exercise when maximal heart rates were attained.