AMPK activation regulates neuronal structure in developing hippocampal neurons

AMP-activated protein kinase (AMPK) is a serine/threonine kinase that functions as a cellular and whole organism energy sensor to regulate ATP-consuming (anabolic) and ATP-generating (catabolic) pathways. The heterotrimeric AMPK complex consists of a catalytic α-subunit, regulatory β-subunit, and an AMP/ATP-binding γ-subunit. Several alternate isoforms exist for each subunit (α1, α2, β1, β2, γ1, γ2 and γ3). However, little is known of the expression pattern or function of the individual catalytic complexes in regulating neuronal structure. In this study, we examined the role of AMPK subunits in differentiating hippocampal neurons. We found that during development, the expression of AMPK subunits increase and that activation of AMPK by energetic stress inhibits neuronal development at multiple stages, not only during axon outgrowth, but also during dendrite growth and arborization. The presence of a single functional AMPK catalytic complex was sufficient to mediate these inhibitory effects of energetic stress. Activation of AMPK mediates these effects by suppressing both the mTOR and Akt signaling pathways. These findings demonstrate that the energy-sensing AMPK pathway regulates neuronal structure in distinct regions of developing neurons at multiple stages of development.

Normal mitral cell dendritic development in the setting of Mecp2 mutation

Rett syndrome (RTT) is an autism spectrum disorder caused by mutation in the gene encoding methyl CpG binding protein 2 (MECP2). Evidence to date suggests that these disorders display defects in synaptic organization and plasticity. A hallmark of the pathology in RTT has been identified as decreased dendritic arborization, which has been interpreted to represent abnormal dendritic formation and pruning during development. Our previous studies revealed that olfactory axons display defective pathfinding and targeting in the setting of Mecp2 mutation. In the present work, we use Mecp2 mutant mouse models and the olfactory system to investigate dendritic development. Here, we demonstrate that mitral cell dendritic development proceeds normally in mutant mice, resulting in typical dendritic morphology at early postnatal ages. We also failed to detect abnormalities in dendritic inputs at symptomatic stages when glomeruli from mutant mice appear smaller in area than the wild type (WT) (6 weeks postnatally). Collectively, these findings suggest that the initial defects in glomeruli impairment seen with Mecp2 mutation do not result from abnormal dendritic development. Our results using the olfactory system indicate that dendritic abnormalities are not an early feature in the abnormalities incurred by Mecp2 mutation.

Percutaneous coronary intervention for persistent complete heart block complicating inferior myocardial infarction

Current guidelines recommend implantation of permanent pacemakers for advanced atrioventricular block complicating acute myocardial infarction (MI) when the block is present beyond the usual hospital course. In patients with inferior MI, such blocks are usually transient, but they can also be persistent. However, they are not considered as primary indications for early reperfusion by percutaneous coronary intervention (PCI) in the absence of ongoing ischemia. We describe a patient with inferior MI in whom a successful PCI was effective in reversing persistent complete heart block, thus avoiding implantation of a permanent pacemaker. In selected patients with inferior MI and advanced atrioventricular block, PCI should be considered as a treatment option before recommending permanent pacemaker implantation.

Clinical Evaluation of an Indigenous Paclitaxel-Eluting Stent in De NovoCoronary Artery Stenosis

BACKGROUND, Drug-eluting stents have enabled considerable reduction in restenosis in patients subjected to angioplasty. However, in view of high cost of drug-eluting stents, efforts to develop medicated stents at reduced cost using alternative polymers in Indian setting are imperative. Hence a multi-center study was undertaken to evaluate the safety and efficacy of the indigenously developed paclitaxel-eluting RELEASE-T stent. METHODS, The study included 100 patients (male:86, Female:14) who were undergoing angioplasty for various indications at four centres viz. Delhi, Hyderabad, Pune and Warangal. The age range was 29 - 76 years; 37 patients were diabetic. All patients were pre-treated with aspirin 150-325 mg plus clopidogrel 75 mg daily four days before procedure or clopidogrel alone. Aspirin was continued indefinitely. RESULTS, Direct stenting ws done in majority of patients. One patient, in whom stent could not be delivered, received only baloon angioplasty. Sixty-four patients had stenting of left anterior descending artery. The stent diameter ranged from 2.5 to 3.5 mm, and the length, 15 to 20 mm. All patients were followed up at 1,3 and 6 months. There was two deaths: one had subacute thrombosis on both stents, and the other (who was HIV positive) had sudden cardiac death. The 6-month rate of major adverse cardiac events was 4% and target lesion revascularization rate ws 2%. CONCLUSION, This ulti-locational study brings out that the use of indigenously developed paclitaxel-eluting stent is safe and clinically efficacious.

Sulfatides: targets for anti-phospholipid antibodies

BACKGROUND

Sulfatides are sulfated glycosphingolipids expressed on the surface of erythrocytes, leukocytes, and platelets. Sulfatides interact with several cell adhesion molecules involved in hemostasis. Beta2-glycoprotein I is an anionic phospholipid-binding plasma protein, and the phospholipid-bound form is the target for most anti-phospholipid antibodies that are associated with recurrent thrombosis, miscarriages, and neurological symptoms. In this study, we examined whether beta2-glycoprotein I forms a complex with sulfatides and thereby becomes a target for anti-phospholipid antibodies.

METHODS AND RESULTS

Beta2-glycoprotein I binds to surface-bound sulfatides but not to other glycolipids, such as ceramide, cerebrosides, sphingomyelin, or ganglioside. At a sulfatide coating density of 1 microg/well, beta2-glycoprotein I reaches half-maximal binding at 2.5 microg/mL, and the binding is saturated at 10 microg/mL. The binding of beta2-glycoprotein I also depends on the coating density of sulfatides in the well. At a constant beta2-glycoprotein I concentration of 5 microg/mL, maximal binding of beta2-glycoprotein I is observed at a coating density of 1 mug/well. The serum from 14 patients with anti-cardiolipin antibodies, a subset of anti-phospholipid antibodies, bound to sulfatide-bound beta2-glycoprotein I and previous absorption on cardiolipin-coated surfaces decreased the immunoreactivity toward sulfatide-beta2-glycoprotein I complex by >50% in 12 of 14 patients. Furthermore, immunoaffinity-purified anti-cardiolipin antibodies from 4 of 5 patients reacted with sulfatide-bound beta2-glycoprotein I.

CONCLUSIONS

These results show that not only anionic phospholipids, as commonly known, but also sulfatides are targets for most anti-phospholipid antibodies. We therefore postulate that interactions of these antibodies with sulfatides may contribute to some of the clinical symptoms of the anti-phospholipid antibody syndrome.

Risk factors for recurrence of atrial fibrillation in patients undergoing hybrid therapy for antiarrhythmic drug-induced atrial flutter

AIMS

Catheter ablation of the inferior vena cava-tricuspid annulus isthmus and continuation of antiarrhythmic drug therapy have been shown to be an effective hybrid therapy for atrial flutter which results from antiarrhythmic drug treatment of atrial fibrillation. The aim of this study was to determine the risk factors for recurrence of atrial fibrillation in patients undergoing hybrid therapy for antiarrhythmic drug-induced atrial flutter.

METHODS AND RESULTS

90 patients with paroxysmal (n=46) or persistent atrial fibrillation (n=44) developed atrial flutter due to the administration of amiodarone (n=48), flecainide (n=22), propafenone (n=14) or sotalol (n=6). Recurrence of atrial fibrillation after ablation was assessed during follow-up on continued antiarrhythmic drug therapy and during long-term follow-up, irrespective of the initial antiarrhythmic medication. During the follow-up on continued antiarrhythmic drug therapy (16+/-13 months), recurrence of atrial fibrillation was documented in 24 of 90 patients (27%). The presence of accompanying pre-ablation episodes of atrial fibrillation on antiarrhythmic treatment (Odds ratio 7.1, 95% confidence interval 2.3 to 25, p=0.001) and decreased left ventricular ejection fraction (Odds ratio 3.7, 95% confidence interval 1.01 to 12.5, p=0.048) were significant and independent predictors of post-ablation atrial fibrillation. Antiarrhythmic medication was discontinued during long-term follow-up due to adverse drug effects (amiodarone, n=12; flecainide, n=1) in 13 patients (14%). During the long-term follow-up, irrespective of the initial antiarrhythmic medication (21+/-15 months), stable sinus rhythm was maintained in 60 of 90 patients (67%). CONCLUSION Hybrid therapy can be considered as the first line therapy for patients with antiarrhythmic drug-induced atrial flutter but patients should be carefully evaluated for accompanying pre-ablation episodes of atrial fibrillation and possible adverse drug effects before initiation of hybrid therapy.

Extensive dissection requiring multiple stents following balloon angioplasty for non-specific aorto-arteritis

Discrete stenoses of the thoraco-abdominal aorta in non-specific aorto-arteritis are considered favorable lesions for balloon angioplasty characterized by good results without major complications. Herein, we describe one such case manifesting with severe hypertension, left ventricular dysfunction and congestive heart failure treated by angioplasty. Balloon dilatation, however, resulted in extensive dissection requiring implantation of two Wallstents. Over a follow-up of one year, hypertension remained under good control with fewer drugs and symptom relief was maintained. Left ventricular ejection fraction improved from 35% to 61%.

Successful inoue balloon valvotomy in a difficult case of mitral stenosis using multiple modifications of technique: alternative method for loop formation of the Inoue balloon catheter

Transseptal puncture was accomplished with difficulty at an unfavorable site in a case of severe mitral stenosis with distorted atrial and septal anatomy. Septal balloon entrapment could not be avoided during attempts to cross the mitral valve using the standard technique. This problem was circumvented by resorting to the loop method and the left ventricle was entered first with a guidewire, which then supported the balloon catheter. Successful mitral valve dilatation could thus be performed. A simple alternative method that was used to form the Inoue balloon catheter into a loop is also described.

Percutaneous transseptal mitral commissurotomy in pregnant women with critical mitral stenosis

BACKGROUND

Percutaneous transseptal mitral commissurotomy has been successfully performed in selected pregnant patients with severe symptomatic mitral stenosis. Its safety and efficacy needs to be evaluated in a large number of cases.

METHODS AND RESULTS

Percutaneous transseptal mitral commissurotomy was performed in 85 severely symptomatic (New York Heart Association functional class III or IV) pregnant women aged 22.7+/-4.1 years (range 18-39 years) with critical mitral stenosis at 24.8+/-4.7 weeks (range 20-34 weeks) of gestation. Percutaneous valvotomy was performed using a flow-guided Inoue balloon in all the patients. The procedure was considered successful in 80 (94%) patients. The hemodynamic mean end-diastolic gradient decreased from 26.7+/-6.8 mm Hg (range 16-35 mmHg) to 4.5+/-3.8 mmHg (range 0-14 mmHg) (p<0.001). The mean diastolic gradient decreased from 29.1+/-9.1 mmHg (range 18-38 mmHg) to 7.2+/-4.1 mmHg (range 4.1-18 mmHg) (p<0.001). The mean mitral valve area assessed by echocardiography increased from 0.75+/-0.5 cm2 (range 0.4-1.0 cm2) to 2.0+/-0.5 (range 1.0-2.7 cm2) (p<0.001). The mean fluoroscopy time was 3.6+/-3.2 minutes. The results of the mitral valvotomy were considered suboptimal in 4 patients. Mitral regurgitation increased by 1 grade in 16 patients and more than 2 grades in 2 patients. One patient developed pericardial tamponade during the procedure and was managed by catheter drainage. Percutaneous mitral valve dilatation was then successfully performed in this patient. No fetal abortion occurred after the procedure.

CONCLUSIONS

The results of this study indicate that percutaneous transseptal mitral commissurotomy is a safe and effective procedure for severe symptomatic mitral stenosis in pregnancy.

Reduced rearing temperature augments responses in sympathetic outflow to brown adipose tissue

Sympathetic outflow to brown adipose tissue (BAT) contributes to both thermoregulation and energy expenditure in rats through regulation of BAT thermogenesis. Acute cold exposure in mature animals augments BAT thermogenesis; however, the enhanced BAT thermogenic response returns to normal shortly after cessation of the cold exposure. In this study, we sought to determine whether cold exposure in early neonatal life could induce enhanced responses in the sympathetic outflow to BAT and whether this altered sympathetic regulation would be sustained after the cold stimulus was removed. BAT sympathetic nerve activity (SNA) was recorded in urethane-chloralose-anesthetized, artificially ventilated rats that were raised from birth in either 18 or 30 degrees C environments and then, at 8 weeks of age, were maintained in 23 degrees C for at least 4 weeks. An acute hypothermic stimulus, disinhibition of a brainstem thermogenic network in the raphe pallidus, or electrical stimulation in this raphe site produced increases in BAT SNA that were twice as great in rats reared at 18 degrees C as in those reared at 30 degrees C. The norepinephrine content of the interscapular BAT (IBAT) and the number of sympathetic ganglion cells projecting to interscapular BAT were 70% greater in the 18 degrees C-reared rats. We conclude that neonatal exposure to a cold environment induces a permanent developmental alteration in the capacity for sympathetic stimulation of BAT thermogenesis that may be mediated, in part, by a greater number of sympathetic ganglion cells innervating BAT in cold-reared animals.

Vibrio cholerae O139 in Calcutta, 1992-1998: incidence, antibiograms, and genotypes

We report results of surveillance for cholera caused by Vibrio cholerae O139 from September 1992, when it was first identified, to December 1998. V. cholerae O139 dominated as the causative agent of cholera in Calcutta during 1992-93 and 1996- 97, while the O1 strains dominated during the rest of the period. Dramatic shifts in patterns of resistance to cotrimoxazole, neomycin, and streptomycin were observed. Molecular epidemiologic studies showed clonal diversity among the O139 strains and continuous emergence of new epidemic clones, reflected by changes in the structure, organization, and location of the CTX prophages in the V. cholerae O139

Utility of coaxial technique for renal angioplasty in patients with a difficult-to-cross stenosis

The aim of this study was to evaluate the feasibility of coaxial approach in difficult-to-cross lesions in patients with failed percutaneous transluminal renal angioplasty by conventional over-the-wire exchange technique. Twelve stenoses in 10 patients (six women and four men; age range 19 +/- 7 years) with uncontrolled hypertension were treated by this method. The stenosis was caused by nonspecific aortoarteritis in 8 patients and fibromuscular dysplasia in 2 patients. It was ostial in seven and post-ostial in five vessels. Conventional exchange technique was unsuccessful in all of them. All procedures were done by femoral route. Technical success was seen in 11 (92%), without complication. The stenosis improved from 90 +/- 2.1% (range 80-100%) to 6 +/- 7% (range 0-20%), blood pressure decreased from 198 +/- 12.3 mm Hg (range 180-220 mm Hg)/130 +/- 6.7 mm Hg (range 120-140 mm Hg) to 119 +/- 5.7 mm Hg (range 110-130 mm Hg)/83 +/- 3.9 mm Hg (range 80-90 mm Hg), and number of drug treatments for hypertension fell from 3.6 +/- 0.52 (range 3-4) to 1 +/- 0.94 (range 0-3; p < 0.01). Percutaneous transluminal renal angioplasty resulted in "cure" in 3 patients and "improvement" in 7 patients. Follow-up period was 3-21 months (mean 6.4 months). No restenosis was detected. Coaxial approach is safe and effective in treating difficult-to-cross lesions in which renal angioplasty by conventional exchange technique is unsuccessful.

Isolated congenital anterior mitral leaflet cleft: a rare cause of mitral insufficiency

BACKGROUND AND AIM OF THE STUDY

Isolated cleft of the anterior mitral leaflet is a rare cause of mitral insufficiency. Although an established entity, due to its rarity the exact anatomic diagnosis is difficult to establish unless sought specifically.

METHODS

Four patients (age range: 16 to 26 years) with isolated cleft of the anterior mitral leaflet were treated at the authors' institute. Clinical symptoms were typical of mitral insufficiency; the exact anatomic diagnosis was not established preoperatively in any patient. The cleft was directly sutured in all four patients and additional annuloplasty was performed in three.

RESULTS

Postoperative echocardiography confirmed satisfactory results. After a mean follow up of 46.7 months (range: 3 to 84 months), one patient had mild mitral insufficiency and the remaining patients had no mitral regurgitation.

CONCLUSION

In severe mitral insufficiency with no obvious mitral valve pathology and an intact atrial septum, a cleft of the anterior mitral leaflet should be sought. Repair of the cleft can restore normal mitral valve function.

Incidence of genitofemoral nerve block during lumbar sympathetic block: comparison of two lumbar injection sites

BACKGROUND AND OBJECTIVES

Genitofemoral nerve (GFN) block is a known side effect of a lumbar sympathetic block (LSB), although the incidence has not been well documented. Furthermore, genitofemoral neuralgia can occur following neurolytic LSB. Because the level at which the GFN exits the psoas sheath varies, this study was designed to identify differences in the incidence of GFN block following LSB at the level of the second versus the fourth lumbar vertebrae.

METHODS

Patients requiring LSB to evaluate chronic lower extremity pain were prospectively studied. Patients were injected at the second lumbar (L2 group) or fourth lumbar (L4 group) vertebral body depending on the location of the pain syndrome in the lower extremity. Lumbar sympathetic blocks were performed using 10 mL of a 0.5% bupivacaine solution with radiocontrast; spread of injectate was verified using fluoroscopy. An observer evaluating for presence of GFN block was blinded to the lumbar level of injection.

RESULTS

Thirty patients were enrolled (L2 group, n = 15; L4 group, n = 15). Spread of local anesthetic/radiocontrast solution was limited to approximately one vertebral body above and one below the target level. There was no difference in the ability to achieve a LSB; success rates were 66% and 73% using L2 and L4, respectively. The incidence of GFN block was 0% (0/15) in the L2 group versus 40% (6/15) in the L4 group; this was statistically significant (P = .017, Fisher's exact test).

CONCLUSIONS

The GFN is less likely to be blocked when the LSB is performed near the second lumbar vertebra as compared with the fourth lumbar vertebra.

Effect of pre-treatment with transdermal glyceryl trinitrate on myocardial ischaemia during coronary angioplasty

OBJECTIVE

In the light of the reported inconsistent anti-ischaemic and antianginal effects of transdermal glyceryl trinitrate, its efficacy and influence on the effects of intracoronary glyceryl trinitrate were examined during coronary angioplasty, which provides a model of controlled, reversible ischaemia.

DESIGN

Double blind, randomised study of the effect of transdermal and intracoronary glyceryl trinitrate on ischaemia during coronary angioplasty.

PATIENTS

40 patients with isolated severe stenosis of the left anterior descending coronary artery.

INTERVENTIONS

Patients were randomised (double blind) to transdermal glyceryl trinitrate (10 mg per day) and placebo, starting four to six hours before angioplasty. After 4 one-minute balloon inflations intracoronary glyceryl trinitrate was injected (0.2 mg) and then 4 further one-minute inflations were performed.

MAIN OUTCOME MEASURES

The time to angina and the time to > 0.2 mV ST shift on surface electrocardiogram (ECG) or intracoronary ECG during the individual inflations.

RESULTS

These times did not significantly differ during initial inflations between transdermal glyceryl trinitrate (27 (11), 25 (9), and 19 (9) s, respectively) and placebo (34 (11), 30 (8), and 21 (7) s. After intracoronary glyceryl trinitrate, they were significantly prolonged compared with the initial values, without differences between patients with transdermal glyceryl trinitrate (37 (10), 30 (8), and 23 (8) s, respectively) or placebo (39 (15), 36 (11), and 28 (12) s). Ischaemic preconditioning was not seen.

CONCLUSIONS

Transdermal glyceryl trinitrate (10 mg per day), unlike intracoronary glyceryl trinitrate, did not alleviate the myocardial ischaemia produced by balloon inflation during coronary angioplasty.

Obstruction to venous outflow from the left lower extremity after renal transplantation

Three patients with acute massive swelling of the left lower extremity occurring soon after placement of a renal allograft in the left iliac fossa are described. In each patient, obstruction to venous outflow from the left lower limb was documented by venography. We surmise that venous obstruction resulted principally from a combination of extrinsic compression of the left iliac vein by the right common iliac artery or by the allograft, and enhanced venous return from the allograft.

Intravenous regional guanethidine in the treatment of reflex sympathetic dystrophy/causalgia: a randomized, double-blind study. Guanethidine Study Group

This double-blind, randomized, multicenter study was designed to determine the short-term and long-term efficacy of intravenous regional block with guanethidine in patients with reflex sympathetic dystrophy (RSD)/causalgia. Sixty patients were enrolled to receive four intravenous regional blocks at 4-day intervals with either guanethidine or placebo in 0.5% lidocaine. Each patient was randomized to receive either one, two, or four blocks with guanethidine. Follow-up visits were scheduled for 4 days, 1 mo, 3 mo, and 6 mo after their final block. At 4 days after the initial block, the group treated with placebo experienced a greater decrease in pain scores than those treated with guanethidine, although this difference was not statistically significant. On long-term followup there was no difference in pain scores between groups receiving one, two, or four guanethidine blocks. Overall, only 35% of patients experienced clinically significant relief on long-term followup even though all were treated early in the evolution of RSD.

A survey of physician knowledge of drug costs

Previous studies have indicated that physicians have inadequate knowledge of drug costs. This study was designed to determine actual pharmacy prices of 12 nonsteroidal anti-inflammatory drugs (NSAIDs) and physicians' knowledge of these prices. Pharmacists (N = 67) in a large urban area were surveyed to determine the lowest retail price of commonly prescribed medications. Pain clinic and orthopedic physicians (N = 95) were surveyed to determine their knowledge of prices for 12 NSAIDs. There was wide variation between pharmacies in the cost of medications. Eighty-one percent of physicians agreed that cost is an important factor to consider. Only 25% of physicians estimated at least one-half of the medications between the highest and lowest pharmacy price. The results of this study indicate that physicians need more information about prices of medications they prescribe.

Collateral arteries in the presence of obstructive coronary disease

BACKGROUND

The clinical importance of coronary collaterals in the presence of obstructive coronary artery disease is not clearly defined.

METHODS

We retrospectively analysed the clinical and angiographic features of 100 patients with > or = 90% luminal diameter stenosis involving at least one major coronary artery. Coronary collaterals were graded 0 to 4 (Nitzberg's classification) and studied to determine their influence on clinical parameters.

RESULTS

Thirty patients had no collaterals (group I) and 70 showed collaterals (group II). There were no significant differences between groups I and II in age and sex distribution, prevalence of risk factors of coronary artery disease (hypertension, diabetes, smoking, hypercholesterolaemia), duration of symptoms of coronary artery disease and prior myocardial infarction. Groups I and II had similar types (left anterior descending 73% v. 71%; left circumflex 50% v. 50% and right coronary 37% v. 56%) and numbers of arteries involved (one 47% v. 41%; two 47% v. 40%; three 7% v. 19%). Group II had a significantly lower prevalence of rest angina (14% v. 47%, p = 0.002). This difference was also evident when the patients were re-classified according to the extent of flow through the collaterals. Those with good collateralization (Nitzberg grades 3 and 4) had a lower prevalence of rest angina (13%) compared to those with poor collateralization (Nitzberg grades 0 to 2; 35%, p = 0.02).

CONCLUSION

Coronary artery collaterals may reduce the incidence of rest angina in patients with obstructive coronary artery disease.

Comparison of the clinical efficacy of three perivascular techniques for axillary brachial plexus block

BACKGROUND AND OBJECTIVES

This study compared the efficacy of three perivascular techniques of axillary block.

METHODS

In group 1, all of the local anesthetic was injected after advancing the needle through the axillary artery (back of artery, n = 20); in group 2, after withdrawing slightly from the artery (front of artery, n = 20); and in group 3, half of the anesthetic was injected after advancing through and half after withdrawing from the axillary artery (half and half, n = 20). The local anesthetic used for the axillary block was 50 ml of 1.5% mepivacaine with epinephrine 1:200,000.

RESULTS

The groups did not differ significantly in the incidence of analgesia or anesthesia expected in the median nerve distribution, where there was a significantly lower incidence of anesthesia in the back of the artery group. This group also had a slower onset of anesthesia for the median and the medial antebrachial cutaneous nerves.

CONCLUSIONS

There was no significant difference in the number of patients requiring supplementation, with five patients in the back group (25%), three patients in the front group (15%), and one patient in the half and half group (5%) requiring supplementation for the surgical procedure.

Clinical profile of biopsy proven idiopathic myocarditis

We studied 20 patients in detail (age: 27 months to 45 years, mean 22 years; 15 males, 5 females) of idiopathic myocarditis histologically confirmed by endomyocardial biopsy. None of these patients had evidence of active or previous rheumatic fever. The commonest mode of presentation was congestive heart failure (16 patients) followed by arrhythmias (seven patients--five of whom had associated congestive heart failure) and chest pain resembling myocardial infarction (two patients). Ten patients had a history of preceding upper respiratory infection. Only one of these patients had a significant rising serum titre for Coxsackie B3 virus. Throat and rectal swabs for virus culture were negative in all patients. The electrocardiogram was abnormal in all patients, with a prolonged corrected QT-interval being the commonest abnormality (14 patients). Serial electrocardiographic patterns of evolving myocardial infarction occurred in three patients. Echocardiographic left ventricular end diastolic dimension (4.15 +/- 1.01 cm/m2) and end systolic dimension (3.37 +/- 1.03 cm/m2) were increased in 15 of the 18 patients studied. Pericardial involvement occurred in only one patient. Radionuclide ventriculography showed a reduced left ventricular ejection fraction (< 50%) in 17 patients, global hypokinesia in 12 patients and regional wall motion abnormalities in five patients. Left ventricular and right ventricular end diastolic pressures were elevated in 15 and 11 patients, respectively.

Effect of sympathetic block demonstrated by triple-phase bone scan

The triple-phase bone scan is frequently used in the diagnosis of reflex sympathetic dystrophy although the etiology of the abnormal findings is not well established. This study evaluated the effect of increased blood flow secondary to sympathetic block on the triple-phase bone scan. In 15 reflex sympathetic dystrophy patients, all of whom had significant relief with sympathetic block, baseline and postsympathetic block bone scans were analyzed. There was a significant linear relationship between change in counts from baseline to postsympathetic block on the blood pool image and bone uptake image. As the blood pool and bone uptake counts increased, the likelihood of typical reflex sympathetic dystrophy findings on visual inspection also increased. These results strongly support the concept of increased vascular flow as the cause of increased periarticular uptake.