Cyclical relationship between depressive symptoms and diabetes distress in people with Type 2 diabetes mellitus: results from the Montreal Evaluation of Diabetes Treatment Cohort Study

AIMS

To determine if longitudinal cyclical relationships exist between depressive symptoms and diabetes distress in people with Type 2 diabetes mellitus.

METHODS

Data were obtained from the Montreal Evaluation of Diabetes Treatment study, a cohort study of 1691 people with Type 2 diabetes mellitus. Depressive symptoms and diabetes distress, measured with the Patient Health Questionnaire and Diabetes Distress Scale, respectively, were assessed at baseline, 1 year and 2 years. A cross-lagged path model analysis with all autoregressive associations was used. Paths and indirect associations were examined.

RESULTS

All paths in the model were significant. Depressive symptoms were positively associated with diabetes distress across consecutive time points and diabetes distress was positively associated with depressive symptoms across consecutive time points. The association between depressive symptoms at baseline and depressive symptoms at 2 years was mediated by both depressive symptoms and diabetes distress at 1 year. The association between diabetes distress at baseline and diabetes distress at 2 years was also mediated by both depressive symptoms and diabetes distress.

CONCLUSIONS

Depressive symptoms and diabetes distress are cyclically related; results suggest that depressive symptoms influence diabetes distress, which, in turn, influences depressive symptoms. Although many studies focus on the differences between depressive symptoms and diabetes distress, the present study is the first to provide longitudinal evidence that these constructs are cyclically related.

SUMO-1 marks the nuclear inclusions in familial neuronal intranuclear inclusion disease

Neuronal intranuclear inclusion disease (NIID) is a rare neurodegenerative disorder characterized by progressive ataxia and neuronal nuclear inclusions (NIs), similar to the inclusions found in expanded CAG repeat diseases. NIID may be familial or sporadic. The cause of familial NIID is poorly understood, as no CAG expansion has been detected. We examined three cases, from two unrelated families, who had autosomal dominant NIID but normal CAG repeats in genes involved in polyglutamine neurodegenerative diseases. We found that NIs in all three cases were intensely immunopositive for SUMO-1, a protein which covalently conjugates to other proteins and targets them to the nuclear regions (nuclear bodies) responsible for nuclear proteasomal degradation. Electron microscopy demonstrated that SUMO-1 was located on the 10-nm fibrils of NIs. In cultured PC12 cells, we found that inhibition of proteasome function by specific inhibitors resulted in the appearance of SUMO-1-immunopositive nuclear inclusions. Our study suggests that recruitment of SUMO-1 modified proteins into insoluble nuclear inclusions and proteasomal dysfunction may be involved in the pathogenesis of NIs in familial NIID cases.

Positron emission tomography and recovery following revascularization (PARR-1): the importance of scar and the development of a prediction rule for the degree of recovery of left ventricular function

OBJECTIVES

The aim of this study was to determine whether the extent of viability or scar is important in the amount of recovery of left ventricular (LV) function, and to develop a model for predicting recovery after revascularization that could be tested in a randomized trial.

BACKGROUND

F-18-fluorodeoxyglucose (FDG) positron emission tomography (PET) is used to define viable myocardium in patients with coronary artery disease (CAD) and severe LV dysfunction and to guide revascularization decisions. Whether this approach improves clinical outcomes has not been tested in a randomized trial. Before doing so, an objective model for prediction of recovery is required.

METHODS

A total of 82 patients with CAD and an ejection fraction (EF) < or =35% had FDG PET perfusion imaging before revascularization. Complete follow-up was available on 70 patients (86%). Patients had radionuclide angiograms at baseline and three months post-revascularization.

RESULTS

Diabetes (p = 0.029), time to operation (p = 0.008), and scar score (p = 0.001) were significant independent predictors of the change in EF. Previous coronary artery bypass graft confounded the effect of age. There was a significant interaction between the perfusion tracer used and mismatch score (p = 0.02). The multivariable prediction model incorporating PET and clinical variables had a goodness of fit with p = 0.001. Across tertiles of scar scores (I, small: 0% to 16%; II, moderate: 16% to 27.5%; III, large: 27.5% to 47%), the changes in EFs were 9.0 +/- 1.9%, 3.7 +/- 1.6%, and 1.3 +/- 1.5% (p = 0.003: I vs. III), respectively.

CONCLUSIONS

In patients with severe LV dysfunction, the amount of scar was a significant independent predictor of LV function recovery after revascularization. A combination of PET and clinical parameters predicts the degree of recovery. This model is being applied in a large randomized controlled trial to determine the effectiveness of therapy guided by FDG PET.

The relationships of left ventricular ejection fraction, end-systolic volume index and infarct size to six-month mortality after hospital discharge following myocardial infarction treated by thrombolysis

OBJECTIVES

We sought to relate left ventricular ejection fraction (EF), end-systolic volume index (ESVI) and infarct size (IS), as measured in a single randomized trial, to six-month mortality after myocardial infarction (MI) treated with thrombolysis.

BACKGROUND

These three prognostic indicators have never been compared in the same study group.

METHODS

Radionuclide angiographic and single-photon emission computed tomographic sestamibi measurements of IS were performed in 1,194 and 1,181 patients, respectively, of the 2,948 patients enrolled in the Collaborative Organization for RheothRx Evaluation (CORE) trial. Ejection fraction, ESVI and IS, as measured by central laboratories in these radionuclide substudies, were tested for their association with six-month mortality.

RESULTS

Ejection fraction (n = 1,137; p < 0.0001), ESVI (n = 945; p = 0.055) and IS (n = 1,164; p = 0.03) were all associated with six-month mortality. Each of these measurements was significantly correlated with the other two, regardless of MI location. In an "overlap" group of 753 patients (25.5% of the population; 13 deaths) in whom all three measurements were available, EF (p = 0.001) was a stronger predictor than ESVI (p = 0.005) or IS (p = 0.01). Neither of the other two measurements added independent prognostic information. The highest risk subgroup (EF < 30%) had an 11% six-month mortality, but comprised only 95 patients (8.3%).

CONCLUSIONS

Ejection fraction, ESVI and IS measurements performed one to two weeks after MI can each predict six-month mortality. Ejection fraction was superior to the other two measurements. However, this study had limited power to detect independent significance of ESVI or IS.

Single photon emission computed tomography dual isotope myocardial perfusion imaging in women with systemic lupus erythematosus. I. Prevalence and distribution of abnormalities

OBJECTIVE

To determine the prevalence of myocardial perfusion abnormalities in women with systemic lupus erythematosus (SLE) using single photon emission computed tomography (SPECT) dual isotope myocardial perfusion imaging (DIMPI).

METHODS

Consecutive female patients registered at the University of Toronto Lupus Clinic were offered DIMPI evaluation and all who accepted were studied. Patients underwent SPECT DIMPI using dipyridamole stress. Resting and stress images were acquired using thallium-201 (201TI) and technetium 99m-sestamibi (99mTc sestamibi), respectively. We recorded segmental perfusion abnormalities, severity and reversibility of any abnormality, and number of vessel territories involved. Ejection fraction was also measured.

RESULTS

One hundred thirty patients were studied. Mean (SD) age and disease duration at study were 45.1 (11.1) years and 14.6 (9.4) years, respectively. Thirteen patients (10%) had a history of angina pectoris or myocardial infarction. Overall, 52 (40%) patients had an abnormality of myocardial perfusion, including 11 (85%) with a history of angina or myocardial infarction. In those with no history of coronary artery disease, 41 (35%) had an abnormality detected. The perfusion defect was reversible in 47 (90%). In 37 (71%) cases perfusion defects were seen in the region of a single vessel territory. Eighteen (13.8%) patients had an ejection fraction (EF) < 50%.

CONCLUSION

Using SPECT DIMPI, 40% of all women with SLE and 35% of women with SLE with no history of coronary artery disease had abnormalities of myocardial perfusion, suggesting a high prevalence of early coronary artery disease. The early detection of disease will facilitate study of atherosclerotic risk factors; such women can also be targeted for a focused program of risk factor management.

Glucose and insulin abnormalities relate to functional capacity in patients with congestive heart failure

AIMS

In addition to diabetes mellitus, less severe abnormalities of glucose and insulin metabolism may be related to functional status in patients with heart failure. We examined the relationship of hyperglycaemia (> or =6.1 mmol. l(-1)) and hyperinsulinaemia (> or =11.2 mU. l(-1)) to functional status and cardiac function in patients with heart failure.

METHODS AND RESULTS

Fasting plasma glucose and insulin levels were obtained in 663 heart failure patients. The average left ventricular ejection fraction was 0.28+/-0.07, 63% were in New York Heart Association Functional Class (NYHA-FC) I/II and 37% were in NYHA-FC III/IV. Twenty seven percent had diabetes mellitus, but an additional 8% had undiagnosed diabetes mellitus (glucose > or =7 mmol. l(-1)) and 9% had glucose levels between 6.1 and 7 mmol. l(-1), so that a total of 43% (287) of patients had elevated glucose levels (> or =6.1 mmol. l(-1)). In general, more diabetic patients had NYHA-FC III/IV symptoms, shorter 6 min walk distances, but similar left ventricular ejection fractions compared to non-diabetic patients. The non-diabetic patients in NYHA-FC III/IV had higher glucose and insulin levels than patients in NYHA-FC I/II (6.3+/-0.2 vs 5.6+/-0.1 mmol. l(-1), P<0.001 and 19.6+/-2.3 vs 10. 2+/-0.6 mU. l(-1), P<0.001). Non-diabetic patients with elevated glucose levels had shorter 6 min walk distances compared to those with normal glucose levels (368.2+/-8 m vs 389.+/-4 m, P=0.02), however, left ventricular ejection fraction was similar.

CONCLUSION

Glucose abnormalities are extremely common in heart failure patients (43% of patients). Diabetes mellitus and hyperglycaemia or hyperlinsulinaemia in non-diabetic patients were related to worse symptomatic status but not worsening left ventricular ejection fraction compared to patients with normal glucose and insulin levels.

Autologous porcine heart cell transplantation improved heart function after a myocardial infarction

OBJECTIVE

Fetal cardiomyocyte transplantation improved heart function after cardiac injury. However, cellular allografts were rejected despite cyclosporine (INN: ciclosporin) therapy. We therefore evaluated autologous heart cell transplantation in an adult swine model of a myocardial infarction.

METHODS

In 16 adult swine a myocardial infarction was created by occlusion of the distal left anterior descending coronary artery by an intraluminal coil. Four weeks after infarction, technetium 99m-sestamibi single photon emission tomography showed minimal perfusion and viability in the infarcted region. Porcine heart cells were isolated and cultured from the interventricular septum at the time of infarction and grown in vitro for 4 weeks. Through a left thoracotomy, either cells (N = 8) or culture medium (N = 8) was injected into the infarct zone.

RESULTS

Four weeks after cell transplantation, technetium 99m-sestamibi single photon emission tomography demonstrated greater wall motion scores in the pigs receiving transplantation than in control animals (P =.01). Pigs receiving transplantation were more likely to have an improvement in perfusion scores (P =.03). Preload recruitable stroke work (P =.009) and end-systolic elastance (P =. 02) were greater in the pigs receiving transplantation than in control animals. Scar areas were not different, but scar thickness was greater (P =.02) in pigs receiving transplantation. Cells labeled with bromodeoxyuridine in vitro could be identified in the infarct zone 4 weeks after transplantation. Swine receiving transplantation gained more weight than control animals (P =.02).

CONCLUSION

Autologous porcine heart cell transplantation improved regional perfusion and global ventricular function after a myocardial infarction.

Absence of heart rate increase during inferoposterior left ventricular hypoperfusion caused by dipyridamole infusion

BACKGROUND

Stimuli such as inferoposterior myocardial infarction and right coronary injection with radiographic contrast media evoke a vasodepressor reflex characterized by bradycardia and hypotension (Bezold-Jarisch reflex). Dipyridamole acts by adenosine-mediated coronary vasodilation to disclose myocardial perfusion heterogeneity for thallium-201 scintigraphy.

OBJECTIVE

To determine whether there is a relationship between the site of left ventricular hypoperfusion and the heart rate response to dipyridamole.

DESIGN

One thousand eight hundred consecutive dipyridamole-thallium studies performed between 1985 and 1993 were reviewed to identify 48 subjects who met prespecified selection criteria.

SETTING

Nuclear cardiology laboratory of a university teaching hospital.

PATIENTS

Group 1 (n=26) had less than 5% pretest likelihood of coronary artery disease and normal thallium perfusion, group 2 (n=10) had isolated, completely reversible anterior perfusion abnormalities, and group 3 (n=12) had analogous inferoposterior perfusion abnormalities.

INTERVENTIONS

Heart rate and blood pressure were recorded at baseline and each minute of supine dipyridamole infusion.

MAIN RESULTS

After 4 mins of dipyridamole infusion, a significant increase in heart rate was observed in group 1 (+12 beats/min, P<0.05) and group 2 subjects (+12 beats/min, P<0.05) but not in group 3 subjects (+3 beats/min, not significant; P=0.016 compared with responses in the other two groups). Blood pressure was not affected by dipyridamole infusion in any group.

CONCLUSIONS

Isolated, moderate or severe inferoposterior hypoperfusion in response to dipyridamole is not accompanied by an increase in heart rate, suggesting that the chronotropic response to dipyridamole is modulated by the presence and location of myocardial perfusion abnormalities. This observation is consistent with the concept that inhibition of adenosine reuptake by dipyridamole, leading to local increases of adenosine concentration, exerts direct and/or reflex effects on heart rate that are site specific. The absence of a rise in heart rate during dipyridamole infusion may be a marker of impaired coronary flow reserve in the inferoposterior left ventricular wall.

Comparison of candesartan, enalapril, and their combination in congestive heart failure: randomized evaluation of strategies for left ventricular dysfunction (RESOLVD) pilot study. The RESOLVD Pilot Study Investigators

BACKGROUND

We investigated the effects of candesartan (an angiotensin II antagonist) alone, enalapril alone, and their combination on exercise tolerance, ventricular function, quality of life (QOL), neurohormone levels, and tolerability in congestive heart failure (CHF).

METHODS AND RESULTS

Seven hundred sixty-eight patients in New York Heart Association functional class (NYHA-FC) II to IV with ejection fraction (EF) <0.40 and a 6-minute walk distance (6MWD) <500 m received either candesartan (4, 8, or 16 mg), candesartan (4 or 8 mg) plus 20 mg of enalapril, or 20 mg of enalapril for 43 weeks. There were no differences among groups with regard to 6MWD, NYHA-FC, or QOL. EF increased (P=NS) more with candesartan-plus-enalapril therapy (0.025+/-0.004) than with candesartan alone (0.015+/-0.004) or enalapril alone(0.015+/-0.005). End-diastolic (EDV) and end-systolic (ESV) volumes increased less with combination therapy (EDV 8+/-4 mL; ESV 1+/-4 mL; P<0.01) than with candesartan alone (EDV 27+/-4 mL; ESV 18+/-3 mL) or enalapril alone (EDV 23+/-7 mL; ESV 14+/-6 mL). Blood pressure decreased with combination therapy (6+/-1/4+/-1 mm Hg) compared with candesartan or enalapril alone (P<0.05). Aldosterone decreased (P<0.05) with combination therapy (23.2+/-5.3 pg/mL) at 17 but not 43 weeks compared with candesartan (0.7+/-7.8 pg/mL) or enalapril (-0.8+/-11. 3 pg/mL). Brain natriuretic peptide decreased with combination therapy (5.8+/-2.7 pmol/L; P<0.01) compared with candesartan (4. 4+/-3.8 pmol/L) and enalapril alone (4.0+/-5.0 pmol/L).

CONCLUSIONS

Candesartan alone was as effective, safe, and tolerable as enalapril. The combination of candesartan and enalapril was more beneficial for preventing left ventricular remodeling than either candesartan or enalapril alone.

Labeling of mitochondrial proteins in living cells by the thiol probe thiobutyltriphenylphosphonium bromide

Alterations to the redox state of mitochondrial thiols is a particularly important response to oxidative stress, because mitochondria are a major source of reactive oxygen species within cells. To investigate these changes we designed and synthesized a novel probe for mitochondrial thiols, thiobutyltriphenylphosphonium bromide [TBTP; R. J. Burns, R. A. J. Smith, and M. P. Murphy (1995) Arch. Biochem. Biophys. 322, 60-68]. This lipophilic cation was accumulated several hundred-fold into the negatively charged matrix of isolated mitochondria, where it equilibrated with endogenous thiols and during oxidative stress formed disulfide bonds to exposed protein thiols. In this paper we show that TBTP can also selectively react with mitochondrial protein thiols in living cells. Since TBTP localizes specifically to mitochondria and forms disulfide bonds selectively with mitochondrial proteins during oxidative stress, we conclude that TBTP has utility for investigating changes in mitochondrial thiols, independently of alterations occurring in the cytoplasm.

Synthesis and characterization of thiobutyltriphenylphosphonium bromide, a novel thiol reagent targeted to the mitochondrial matrix

Mitochondria are continually exposed to oxidative stress due to superoxide formation by the respiratory chain which increases in pathological situations such as ischemia reperfusion and neurodegeneration. During oxidative stress there are a number of changes in mitochondrial low-molecular-weight and protein thiols. In particular, the mitochondrial glutathione pool becomes oxidized and forms mixed disulfides with protein thiols. To investigate changes in the redox state and conjugation of mitochondrial glutathione, and other mitochondrial thiols, we designed and characterized a thiol probe specifically targeted to the mitochondrial matrix. This molecule, thiobutyltriphenylphosphonium bromide, contains a thiol group linked to a lipophilic triphenylphosphonium cation which causes it to accumulate in the negatively charged mitochondrial matrix. Using [14C]thiobutyltriphenylphosphonium bromide we confirmed that it was selectively accumulated by isolated mitochondria. In the mitochondrial matrix the thiol group equilibrated with endogenous thiols and during oxidative stress became disulfide-bonded to protein and nonprotein thiols. Therefore, this novel thiol probe can be used to label protein thiol groups and to investigate changes in conjugation and redox state of mitochondrial thiols during oxidative stress.

Prognostic significance of increased thallium-201 lung uptake during dipyridamole myocardial scintigraphy: comparison with exercise scintigraphy

OBJECTIVE

To compare the incidence of cardiac events among patients with increased lung uptake of thallium after dipyridamole stress, matched subjects without such uptake and matched subjects with increased lung uptake during exercise stress.

DESIGN

Retrospective case control study based on quantitative and semiquantitative visual consensus analysis of thallium scintigraphy.

SETTING

Nuclear cardiology laboratory of a university teaching hospital.

PATIENTS

Thirty-six patients with increased lung activity after dipyridamole stress and two groups of matched control subjects identified from 3150 consecutive thallium single photon emission computed tomography studies.

INTERVENTIONS

Telephone follow-up and chart reviews to determine the incidence of cardiac events.

MAIN RESULTS

Cardiac events were significantly less frequent in the study group with increased lung uptake after dipyridamole stress (two of 36,5%) than in the control group with increased thallium lung uptake at exercise scintigraphy (nine of 36,25%; P = 0.046).

CONCLUSIONS

Increased lung uptake of thallium has less ominous short term prognostic significance when observed in association with dipyridamole stress rather than with exercise.

Identification of viable myocardium with technetium-99m-MIBI infusion

A 50-yr-old man was evaluated using standard stress/rest 99mTc-methoxyisobutylisonitrile (MIBI) perfusion imaging, rest thallium infusion imaging and rest 99mTc-MIBI infusion imaging prior to revascularization. Resting 99mTc-MIBI infusion imaging demonstrated hibernating myocardium which was not detected with standard stress/rest 99mTc-MIBI imaging. The implication from this observation is that resting 99mTc-MIBI infusion scintigraphy can provide useful information when evaluating patients for the presence of hibernating myocardium. A prospective comparison of resting 99mTc-MIBI infusion scintigraphy with other noninvasive techniques used to identify viable myocardium may be warranted.

The Canadian exercise technetium 99m-labeled teboroxime single-photon emission computed tomographic study. Canadian Exercise Teboroxime SPECT Study Investigators

BACKGROUND

99mTc-labeled teboroxime undergoes rapid washout from the myocardium. For this reason, its use has been favored in conjunction with pharmacologic stress, which enables patient positioning before tracer administration, and multidetector single-photon emission computed tomography (SPECT), which enables rapid acquisition. We evaluated treadmill exercise 99mTc-labeled teboroxime SPECT with single-detector systems for the detection of coronary artery disease.

METHODS AND RESULTS

Treadmill exercise 99mTc-labeled teboroxime SPECT was compared with analogous 201Tl-labeled imaging in 108 patients. Teboroxime was injected first during exercise and then at rest. Nine myocardial segments per study were scored with respect to uptake of activity during stress and at rest (teboroxime) or after redistribution (201Tl). Perfusion was defined as normal, reversible, or fixed. Overall agreement of 201Tl versus teboroxime segmental perfusion (normal vs abnormal) was 772/961 (80.3%; chi 2 = 258; p < 0.001; kappa = 0.51) or (normal vs reversible vs fixed) 711/961 (74.0%; chi 2 = 296; p < 0.001; kappa = 0.42). Fifty-six patients also underwent selective coronary angiography. Stenoses greater than 50% of lumenal diameter were drawn on individualized coronary artery diagrams applied to polar plots of scintigraphic segments to compare detection of coronary artery disease. Sensitivity and accuracy of teboroxime were 0.80 and 0.79, respectively, compared with 0.84 and 0.82 for 201Tl (difference not significant). Mean imaging procedure time was 113.6 minutes for teboroxime and 240.5 minutes for 201Tl (p < 0.001).

CONCLUSIONS

99mTc-labeled teboroxime is amenable to simple modifications of routine treadmill exercise SPECT myocardial perfusion imaging protocols with widely available single-detector SPECT systems. This modality provides results similar to those of exercise 201Tl SPECT and is significantly faster.

Toxicity of Compound 1080 livestock protection collars to sheep

The toxicity of Compound 1080 (sodium fluoroacetate) livestock protection collars (LPCs) to sheep was investigated. Lambs wearing punctured LPCs were observed to determine dermal toxicity, sheep were fed hay treated with LPC solution to find a lethal concentration, hay treated with a lethal concentration was subjected to sun and simulated rain to assess weathering influences, and sheep were held on pasture treated with LPC solution to evaluate grazing effects. Five lambs that wore punctured LPCs for up to seven days showed no dermal erythema or edema, but three died after ingesting 1080 from LPCs. All sheep died after eating 1.0 kg of hay treated with 3.75 ml, or more, of 1.0% LPC solution. Weathering 1.0 kg of hay treated with 3.75 ml of LPC solution in the sun for up to 12 weeks, reduced, but did not eliminate, toxicity; one inch or more of simulated rain eliminated toxicity. Survival of sheep in 250 m2 pens containing 1.1 m2 of forage treated with different amounts of LPC solution depended on the treatment and amount of treated forage consumed. LPC solution poses no dermal toxicity or irritation to sheep, and toxic effects on sheep from LPC solution on hay and forage was variable and situation dependent. Under conditions of exaggerated hazard, sheep can be poisoned by ingesting LPC solution, but adverse effects from normal LPC use are rare.

Late hemodynamic effects of the preserved papillary muscles during mitral valve replacement

BACKGROUND

The late hemodynamic effects of preserving the papillary muscles during mitral valve replacement have not been evaluated.

METHODS AND RESULTS

Sixteen patients who had chronic mitral regurgitation due to myxomatous degeneration were randomized to preservation (Pres group, n = 8) or no preservation (No Pres group, n = 8) of the chordae tendineae and papillary muscles during mitral valve replacement. Rest and exercise nuclear ventriculograms were performed early (3 months) and late (5 years) after surgery. Early after surgery, the No Pres group had lower ejection fractions and stroke work indexes (P < .05 by repeated-measures [rm] ANOVA) than the Pres group did at similar end-diastolic volume indexes. The No Pres group had similar cardiac indexes after exercise because heart rate increased (P < .005 by rm ANOVA). Late after surgery, ejection fraction was greater at similar end-diastolic volume indexes (P < .005 by rm ANCOVA), and preload recruitable stroke work indexes (P < .001 by rm ANCOVA) were better in the Pres group.

CONCLUSIONS

Preserving chordal attachments enhanced the late hemodynamic recovery after mitral valve replacement for mitral regurgitation.

Benign familial disease with muscle mounding and rippling

Four members of a family in three generations exhibited unusual clinical features of localised transient swelling of muscle induced by percussion (muscle mounding or myoedema) and were able, voluntarily, to induce rhythmic waves of contraction in certain muscles (muscle rippling or rolling). All had raised serum creatine kinase activity. Muscle biopsy in two members showed no specific abnormality. Experimental studies performed on excised intercostal muscle showed that abnormal "after-contractions" and increased sarcolemmal excitability could be demonstrated in vitro.

Protracted form of encephalitis with good outcome

OBJECTIVE

To present four patients seen over a five-year period who developed severe protracted encephalitic illnesses but whose outcomes were favourable.

CLINICAL FEATURES

Of the four patients, aged 18, 22, 34 and 19, three presented with acute psychosis, and all had a prolonged clinical course requiring intensive care management. One patient had residual generalised seizures and the other three recovered fully. No infective or toxic agent could be identified but viral encephalitis was considered most likely.

OUTCOME

Despite the protracted courses, the outcomes were favourable. This is in contrast to the generally poor outcomes in encephalitis caused by established infective agents such as herpes simplex type 1.

CONCLUSIONS

When the aetiology and hence the natural history of the encephalitis is unknown, long-term intensive support is appropriate.

Reverse redistribution on exercise thallium scintigraphy: relationship to coronary patency and ventricular function after myocardial infarction

OBJECTIVE

To define prevalence, pathophysiology and relation to thrombolytic therapy of reverse redistribution (appearance of a new, or worsening of an existing, scintigraphic defect on 4 h delayed images compared with the stress thallium image).

DESIGN

Randomized, double-blind, placebo-controlled trial.

SETTING

Referral centre.

PATIENTS

Sixty-three patients with acute myocardial infarction.

INTERVENTIONS

Tomographic exercise thallium scintigraphy, radionuclide angiography, and quantitative coronary angiography.

MAIN RESULTS

Tomographic exercise thallium scintigraphy performed at day 10 revealed fixed defects in 15 patients, reversible defects in 22 patients and reverse redistribution in 26 patients; no difference in treatment assignment (tissue plasminogen activator versus placebo) was found among the three groups. Left ventricular function was similar in patients with fixed or reversible defects and reverse redistribution; global ejection fraction was 48 +/- 14, 51 +/- 10 and 48 +/- 5%, respectively, and regional infarct ejection fraction was 36 +/- 15, 40 +/- 13 and 37 +/- 18%, respectively. However, nitroglycerin administration resulted in a significantly greater improvement in regional ejection fraction in reverse redistribution patients (5 +/- 4%) than that in patients with fixed defect (2 +/- 5%, P < 0.05) or reversible defects (3 +/- 5%, P < 0.05). The infarct-related artery had a greater cross-sectional area in reverse redistribution patients (1.5 +/- 1.42 mm2) compared with those with reversible defects (0.50 +/- 0.26 mm2, P < 0.05), but was similar to fixed defect patients (1.04 +/- 0.88).

CONCLUSIONS

Reverse redistribution on tomographic thallium scintigraphy is a frequent phenomenon (occurring in 40% of patients following acute myocardial infarction) and is independent of thrombolytic therapy. Patients with reverse redistribution have a more widely patent infarct-related artery and similar ventricular function, but significantly greater functional improvement following nitroglycerin administration compared with those with reversible or fixed defects. These data suggest myocardial salvage within the infarct zone in some patients with reverse redistribution.

Postoperative haemodynamic and pharmacological responses in patients with positive technetium pyrophosphate single-photon emission computed tomography following CABG

The aim of this prospective study was to evaluate the postoperative haemodynamic variables and medication requirements in patients with perioperative myocardial infarction (PMI), following elective coronary artery bypass graft (CABG) surgery, as documented by technetium pyrophosphate scintigraphy using single-photon emission computed tomography (TcPPi-SPECT). A high-dose fentanyl anaesthetic technique was applied. Twelve of 58 patients (21%) developed PMI with an infarcted myocardial mass of 35.7 +/- 3.9 g. Over the 48 hr postoperative period, patients with positive TcPPi-SPECT (n = 12) did not differ from those with negative TcPPi-SPECT (n = 46) in mean heart rate (below 100 bpm), systolic blood pressure (100-120 mmHg) or central venous pressure (8-16 mmHg). However, patients with positive TcPPi-SPECT had higher pulmonary artery diastolic pressures at 5-8 hr after surgery. No differences were found in the incidence and dosage requirements for postoperative sedative or vasoactive drugs (morphine, diazepam, propranolol, lidocaine, nitroglycerin and nitroprusside) between the two groups. There was no difference in the incidence of dopamine requirement between the groups (positive-scan: 16.7%, negative-scan: 13.0%). However, the dopamine dosage for inotropic support was higher in the positive TcPPi-SPECT group over 24 hr (318.5 +/- 125.2 mg vs 71.2 +/- 24.7 mg, P less than 0.05) and 48 hr (869.1 +/- 19.0 mg vs 142.3 +/- 49.4 mg, P less than 0.001) periods after surgery. We postulate that careful control of postoperative haemodynamic variables did not prevent but may limit the extent of PMI in elective CABG patients.

Improved specificity of myocardial thallium-201 single-photon emission computed tomography in patients with left bundle branch block by dipyridamole

Reduced septal uptake of thallium-201 during exercise is frequently observed in patients with left bundle branch block (LBBB) and normal coronary arteries. This may reflect normal coronary autoregulation in response to lower septal oxygen demand; thus, dipyridamole, which uniformly exploits flow reserve, would be more accurate for diagnosis of coronary artery disease (CAD). Sixteen patients with LBBB underwent exercise and dipyridamole thallium-201 single-photon emission computed tomography and coronary angiography within 3 months. Sensitivity for detection of left anterior descending CAD (greater than 50% stenosis) was 0.83 for exercise and 1.00 for dipyridamole. Specificity was 0.30 (visual) or 0.20 (quantitative analysis) for exercise and 0.80 (visual) or 0.90 (quantitative) for dipyridamole (p less than 0.05). Dipyridamole combined with quantitative analysis also improved specificity of CAD detection overall (p less than 0.01). These data demonstrate that pharmacologic vasodilation is more accurate than exercise when diagnosing CAD by myocardial perfusion scintigraphy in patients with LBBB.

Controlled release levodopa/carbidopa (Sinemet CR4) in Parkinson's disease--an open evaluation of efficacy and safety

Twenty patients with moderately severe Parkinson's disease entered an open study of the efficacy and safety of a slow release preparation containing levodopa 200 mg and carbidopa 50 mg per tablet ('Sinemet CR4'). Following an initial four week baseline stabilisation period on conventional 'Sinemet' tablets, the patients were transferred to 'Sinemet CR4' and observed at intervals over the next 12 months. Fifteen patients completed the full year observation period. When compared with the baseline period, treatment with 'Sinemet CR4' was associated with longer periods of functional improvement and less fluctuation of response following each dose. The median (range) dose frequency was reduced from three (three-12) to two (two-seven) times daily (p less than 0.001) on 'Sinemet CR4' although median (range) total daily dose of levodopa was increased from 700 (375-2525) to 800 (400-2800) mg without any increase in adverse effects. Three patients developed peripheral neuropathy while receiving Sinemet CR4, but the association with this therapy is unclear. Overall 'Sinemet CR4' allowed a longer dosage interval and provided more stable control of disease manifestations than conventional 'Sinemet'.

Cardiac effects of prazosin in chronic aortic insufficiency

Eight patients with chronic moderate to severe aortic insufficiency were assessed by radionuclide angiography at rest and during maximal bicycle exercise after six weeks of placebo, six weeks of prazosin titration up to 10 mg bid and 12 weeks of prazosin maintenance therapy. Prazosin was well tolerated and the final dose amounted to 18.6 +/- 0.7 mg/day. Exercise performance tended to increase (from 8.9 +/- 1.1 to 9.6 +/- 0.8 mins). Resting and exercise blood pressure and heart rate were not affected by prazosin. Left ventricular volumes were decreased and exercise ejection fraction increased by prazosin. Total left ventricular output decreased, whereas regurgitant index improved. The authors conclude that in patients with chronic moderate to severe aortic insufficiency, chronic prazosin therapy causes persistent improvements in left ventricular anatomy and function both at rest and during exercise.

South Australian carotid endarterectomy study

OBJECTIVE

To determine the operative morbidity and mortality of carotid endarterectomy in South Australia.

DESIGN

This was a prospective study on consecutive patients already selected independently by their treating clinicians for carotid endarterectomy. Patients were assessed before and after the operation by independent neurologists.

SETTING AND PARTICIPANTS

The study involved all patients undergoing carotid endarterectomy in South Australia in public and private hospitals over the 20-months period of the study. All vascular surgeons agreed to participate.

INTERVENTION

Two hundred and thirty-nine carotid endarterectomies were performed on 223 patients, always as primary procedures.

MAIN OUTCOME MEASURES

Patient characteristics, angiographic findings and indications for surgery were documented before the operation by neurologists who then carried out postoperative assessments and determined neurological status at discharge. Follow-up at six and twelve months was by letter and telephone enquiry to general practitioners or direct to patients.

RESULTS

The perioperative death and stroke rate was 6.3% including one stroke after angiography and before endarterectomy. Fourteen patients (5.9%) had strokes after the operation and three died as a result (1.3%). Three patients had reversible ischaemic neurological deficits. In 58 asymptomatic patients, operative morbidity was 3.4%. However, in 42 patients who had had a stroke before the operation, there were seven who had operative complications (16.7%). Neurological complication rates for individual surgeons varied from 0 to 13.8%. In the subsequent 12 months, follow-up of 214 patients revealed nine additional deaths (three known to be caused by stroke, four not caused by stroke and two of unknown cause) and six more cerebral infarctions (involving both operated and unoperated sides), an annual mortality plus stroke morbidity rate of 4.2%-5.1%.

CONCLUSIONS

The morbidity and mortality of carotid endarterectomy in South Australia is acceptable by world standards but is high in the subgroup with a preceding stroke. In this audit, carotid endarterectomy had an average risk at least equal to one year of untreated carotid artery disease and did not diminish the expected stroke and death incidence after one year.

Creutzfeldt-Jakob disease in a recipient of human pituitary-derived gonadotrophin

A forty-year-old female presented with an unsteady gait 13 years after receiving an eight-month course of human pituitary-derived gonadotrophin injections as treatment for infertility. Over the next ten months the patient subsequently developed generalised myoclonic jerks and dementia and finally died. Neuropathological examination revealed changes in the brain consistent with Creutzfeldt-Jakob disease. This is the first reported case of Creutzfeldt-Jakob disease in a recipient of human derived gonadotrophin.

Effects of nifedipine versus hydralazine on sympathetic activity and cardiac function in patients with hypertension persisting on diuretic plus beta-blocker therapy

In patients with hypertension persisting on combined diuretic and beta-blocker therapy, the effects of an additional 9-week therapy with a calcium antagonist (nifedipine) versus a classical arterial vasodilator (hydralazine) were compared for changes in blood pressure (BP), plasma catecholamines (n = 15), and left ventricular (LV) systolic and diastolic function (n = 6). Both drugs lowered BP, but nifedipine was significantly more effective in lowering systolic BP. Hydralazine increased both supine and standing plasma norepinephrine, nifedipine increased them only in the standing position and to a lesser extent. Patients on beta1-selective (n = 5) versus nonselective (n = 10) blockade showed similar responses. Left ventricular systolic function was not affected by hydralazine, whereas nifedipine increased the rate of ejection. In contrast, LV diastolic function was not affected by nifedipine, whereas hydralazine improved the peak filling rate. We conclude that arterial vasodilation by a calcium antagonist causes less sympathetic activation than caused by a classical arterial vasodilator. However, during short-term therapy in patients already on a diuretic and a beta blocker, nifedipine appears not to improve decreased LV diastolic function.

Covert orientation of visual attention in Parkinson's disease: an impairment in the maintenance of attention

Covert orientation of attention was studied in a group of patients with idiopathic Parkinson's disease and compared to a matched control group using a cued reaction time task which measured disengagement, covert movement and engagement of attention. Parkinson patients had an increased response latency and disengaged from attended locations more readily than controls. This impairment in the maintenance of attention in Parkinson's disease was comparable to that produced in a previous study by pharmacological blockade of brain catecholamines in normal subjects. It is suggested that an impairment in the maintenance of oriented attention may underlie some of the cognitive deficits reported in Parkinson's disease.

Postoperative myocardial infarction documented by technetium pyrophosphate scan using single-photon emission computed tomography: significance of intraoperative myocardial ischemia and hemodynamic control

The aim of this prospective study was to document postoperative myocardial infarction (PMI) by technetium pyrophosphate scan using single-photon emission computed tomography (TcPPi-SPECT) in 28 patients undergoing elective coronary bypass grafting (CABG). The relationships of intraoperative electrocardiographic myocardial ischemia, hemodynamic responses, and pharmacological requirements to this incidence of PMI were correlated. Radionuclide cardioangiography and TcPPi-SPECT were performed 24 h preoperatively and 48 h postoperatively. A standard high-dose fentanyl anesthetic protocol was used. Twenty-five percent of elective CABG patients were complicated with PMI, as documented by TcPPi-SPECT with an infarcted mass of 38.0 +/- 5.5 g. No significant difference in demographic, preoperative right and left ventricular function, number of coronary vessels grafted, or aortic cross-clamp time was observed between the PMI and non-PMI groups. The distribution of patients using preoperative beta-adrenergic blocking drugs or calcium channel blocking drugs was found to have no correlation with the outcome of PMI. As well, no significant differences in hemodynamic changes or pharmacological requirements were observed in the PMI and non-PMI groups during prebypass or postbypass periods, indicating careful intraoperative control of hemodynamic indices did not prevent the outcome of PMI in these patients. However, the incidence of prebypass ischemia was 39.3% and significantly correlated with the outcome of positive TcPPi-SPECT, denoting a 3.9-fold increased risk of developing PMI. Prebypass ischemic changes in leads II and V5 were shown to correlate with increased CPK-MB release (P less than 0.05) and tends to occur more frequently with lateral myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Myocardial infarction determined by technetium-99m pyrophosphate single-photon tomography complicating elective coronary artery bypass grafting for angina pectoris

The incidence of acute myocardial infarction (AMI) complicating coronary artery bypass grafting (CABG) has previously been based on concordance of electrocardiographic, enzymatic and scintigraphic criteria. Technetium-99m pyrophosphate (Tc-PPi) single-photon emission computed tomography now enables detection of AMI with high sensitivity and specificity. Using this technique, perioperative AMI was detected in 12 of 58 patients (21%) undergoing successful elective CABG for stable angina pectoris. Stepwise multivariate logistic regression analysis was performed to compare the predictive value of preoperative (New York Heart Association class, left ventricular ejection fraction and use of beta blockers) and intraoperative (number of grafts constructed, use of internal mammary anastomoses, use of sequential saphenous vein grafts, smallest grafted distal vessel lumen caliber and aortic cross-clamp time) variables. Preoperative New York Association class (p = 0.04) and smallest grafted distal vessel lumen caliber (p = 0.03) were significant multivariate predictors of perioperative AMI. Only 1 perioperative patient with AMI (and 1 pyrophosphate-negative patient) developed new Q waves. Serum creatine kinase-MB was higher in patients with AMI by repeated measures analysis of variance (p = 0.0003). Five AMIs occurred in myocardial segments revascularized using sequential saphenous vein grafts, and 7 in segments perfused by significantly stenosed epicardial vessels with distal lumen diameter and perfusion territory considered too small to warrant CABG. At 6-month follow-up, the mean left ventricular ejection fraction increased from 0.61 to 0.65 in Tc-PPI-negative patients (p = 0.01), but not in perioperative patients with AMI.(ABSTRACT TRUNCATED AT 250 WORDS)

Mitral valve annuloplasty: the effect of the type on left ventricular function

This study was undertaken to determine whether rigid-ring annuloplasty and flexible-ring annuloplasty have the same effect on left ventricular function in patients with chronic mitral regurgitation secondary to degenerative disease of the mitral valve. Twenty-five patients who underwent isolated mitral valve repair and required annuloplasty were randomized into two groups: rigid-ring and flexible-ring annuloplasty. Left ventricular function was assessed by echocardiography and radionuclide angiography on the day before operation and 2 to 3 months later. Preoperative left ventricular function was similar in the two groups of patients. Postoperatively, left ventricular end-diastolic diameter and volume decreased significantly in both groups. The left ventricular end-systolic diameter and volume decreased significantly only in patients with a flexible annuloplasty ring. Left ventricular systolic function as assessed by pressure-volume relationships was significantly better in patients with a flexible ring (p less than 0.02 by analysis of covariance), and left ventricular performance measured by stroke volume-end-diastolic volume relationships was also better in these patients (p less than 0.05 by analysis of covariance). These data indicate that patients with a flexible annuloplasty ring have better left ventricular systolic function than patients with a rigid annuloplasty ring 2 to 3 months after mitral valve reconstruction for chronic mitral regurgitation secondary to degenerative disease of the mitral valve.

Effect of antianginal medications on the prognostic value of exercise thallium scintigraphy

Whether administration of antianginal medications at the time of exercise thallium scintigraphy reduces the prognostic value of this test was retrospectively examined using two year follow-up of 201 patients. Sensitivity, specificity, positive and negative predictive values and accuracy of five test outcomes for prediction of coronary events (unstable angina, myocardial infarction, cardiac death) were compared between groups of patients either taking or not taking antianginal medications. Specificity and negative predictive value of exercise and redistribution thallium scores for prediction of coronary events were greater in patients not taking antianginal medication (P less than 0.05). It was concluded that normal exercise thallium scintigraphy affords greater assurance against future coronary events in patients tested while not taking antianginal medications.

Calcium channel blockade does not offer adequate protection from perioperative myocardial ischemia

This study aimed to detect the difference in hemodynamic and electrocardiographic responses during the prebypass period in patients undergoing coronary bypass grafting who were receiving beta-adrenergic blocking drugs, calcium entry blocking drugs, or both beta-adrenergic and calcium entry blocking drugs. Electrocardiographic evidence of myocardial ischemia was noted significantly more frequently in patients receiving calcium entry blocking drugs alone at induction of anesthesia (P less than 0.03), skin incision (P less than 0.05), and sternotomy (P less than 0.002). Heart rate at sternotomy was significantly higher in patients receiving calcium entry blocking drugs (P less than 0.02) as compared to patients receiving beta-adrenergic blocking drugs or the combination of both drugs. In conclusion, patients treated with calcium entry blocking drugs alone had significantly higher incidence of perioperative ischemic ECG changes compared with patients receiving beta-adrenergic blocking drugs alone or in combination with calcium channel blocking drugs.

Prenatal and adult presymptomatic testing for Huntington's disease

The discovery of a fragment of DNA that is linked closely to the Huntington's-disease autosomal locus offers the opportunity for the presymptomatic diagnosis of this dominantly-inherited neurodegenerative disorder. Presymptomatic testing will present individuals and society with difficult choices and responsibilities. A pilot adult presymptomatic test programme is under way for SA families. Presymptomatic testing requires intensive counselling both before and after the test. A form of prenatal test, which is applicable to a significant proportion of couples with one partner at risk of Huntington's disease, is available also. As this form of prenatal test does not change the risk status of the parent, less extensive counselling is required and testing is available nationally through the SA programme. It is anticipated that other states will develop their own diagnostic programmes in the near future. This article explains the basis for the test, its accuracy and the importance of obtaining DNA from key individuals in pedigrees of Huntington's disease.

Usefulness of radionuclide angiocardiography in predicting stenotic mitral orifice area

Fifteen patients with pure mitral stenosis (MS) underwent high-temporal-resolution radionuclide angiocardiography for calculation of the ratio of peak left ventricular (LV) filling rate divided by mean LV filling rate (filling ratio). Whereas LV filling normally occurs in 3 phases, in MS it is more uniform. Thus, in 13 patients the filling ratio was below the normal range of 2.21 to 2.88 (p less than 0.001). In 11 patients in atrial fibrillation, filling ratio divided by mean cardiac cycle length and by LV ejection fraction provided good correlation (r = 0.85) with modified Gorlin formula derived mitral area and excellent correlation with echocardiographic mitral area (r = 0.95). Significant MS can be detected using radionuclide angiocardiography to calculate filling ratio. In the absence of the confounding influence of atrial systole calculation of 0.14 (filling ratio divided by cardiac cycle length divided by LV ejection fraction) + 0.40 cm2 enables accurate prediction of mitral area (+/- 4%). Our data support the contention that the modified Gorlin formula, based on steady-state hemodynamics, provides less certain estimates of mitral area for patients with MS and atrial fibrillation, in whom echocardiography and radionuclide angiocardiography may be more accurate.

Validation of cardiac single photon emission tomography of labeled intracoronary microspheres as a method to measure changes in distribution of coronary blood flow

Single photon emission tomography (SPECT) combined with intracoronary dual-labelled microspheres (Tc-99m and In-111) is a technique that can potentially measure changes in regional coronary blood distribution. To validate the ability of microspheres to measure regional coronary flow distribution, we studied this method in 5 pigs to evaluate 3 specific questions: Does the lack of attenuation correction affect the calculation of relative concentrations of microspheres? Do Tc and In microspheres have similar imaging characteristics? Is there correlation between tomographic concentrations of tracer activity and tissue concentration of microspheres? Tc and In albumin microspheres were injected selectively down the left anterior descending coronary artery, and dual-isotope SPECT imaging of the whole heart was carried out. The heart was then sliced and the slices imaged directly on the collimator. Finally the slice was sectioned and well counted. The correlation coefficient (R) between SPECT profiles and direct camera profiles was 0.91. The R between In and Tc counts was also excellent at 0.93. Comparing SPECT profiles and well counting, the R was 0.79 for Tc and 0.72 for In microspheres, with the standard error of estimate less than 8.7% and 14.5% respectively about the mean value. Therefore; SPECT of intracoronary microspheres does correspond to tissue concentrations of microspheres, lack of attenuation correction does affect the correlation but not to a significant extent, In and Tc microspheres have very similar imaging characteristics. SPECT of dual intracoronary microspheres may provide a potentially useful tool to assess distribution of regional coronary blood flow.

Cardiovascular effects of enprofylline and theophylline

The cardiovascular effects of enprofylline (with no adenosine receptor antagonism) and of theophylline (with adenosine receptor antagonism) were compared in six normal subjects in a double-blind trial at steady-state concentrations of theophylline (12.5 +/- 1.6 mg/L) and enprofylline (2.7 +/- 0.3 mg/L). The mean (+/- SD) recumbent heart rate (HR) was higher (P less than 0.04) after enprofylline (70 +/- 14 bpm) than after theophylline (58 +/- 13 bpm) or saline solution (57 +/- 10 bpm). Forearm arterial resistance determined by plethysmography was lowered (P less than 0.01) by theophylline (-37% +/- 14%) and enprofylline (-43% +/- 24%) but not by saline solution (-6% +/- 16%). In the semiupright position, the mean arterial pressure was lower (P less than 0.01) after enprofylline (93 +/- 15 mm Hg) than after theophylline (108 +/- 16 mm Hg). The cardiac index (CI) and left ventricular ejection fraction (LVEF) determined by radionuclide angiocardiography and the left ventricular end-systolic pressure/volume ratio were not different for any regimen. During maximal exercise, HR was higher (P less than 0.01) after both enprofylline (176 bpm) and theophylline (175 bpm) than after saline solution (161 bpm), but the increases in mean arterial pressure (18% to 32%), CI (153% to 167%), and LVEF (34% to 74%) were similar for all three regimens. Both theophylline and enprofylline lowered forearm arterial resistance without an increase in CI, LVEF, or cardiac inotropy, although enprofylline tended to cause a lower blood pressure and higher HR than did theophylline.