Chronic posttraumatic movement disorder alleviated by insertion of meso-diencephalic deep brain stimulating electrode

Incapacitating and drug-resistant posttraumatic movement disorders have successfully been treated by stereotactic thalamotomy. We describe the case of a young man with a posttraumatic hemiballismoid type movement disorder of the left arm, persistent for 2 years, who was selected for treatment with a thalamic deep brain stimulator. However, placement of the stimulating electrode tip at the junction of the zona incerta and subthalamic regions caused abolition of the movement disorder, and the pulse generator was not required. Reassessment over a 44-month period using multiple clinical and functional tests has confirmed continued benefit. This case adds to the reports of alleviation of movement disorders following either stereotactic thalamic mapping or placement of stimulating electrodes without macroscopic thalamic lesioning.

Trends in the number and administrative characteristics of medical school health promotion programmes

Over the course of almost 10 years, 1988-97, there has been a significant decline in the number of United States and Canadian medical schools offering health promotion programmes for students. All efforts should be made to enhance the overall health and well-being of medical students and to increase the number of health promotion programmes for them.

The expanded human kallikrein (KLK) gene family: genomic organisation, tissue-specific expression and potential functions

The tissue kallikreins are serine proteases encoded by highly conserved multi-gene families. The rodent kallikrein (KLK) families are particularly large, consisting of 13-26 genes clustered in one chromosomal locus. It has been recently recognised that the human KLK gene family is of a similar size (15 genes) with the identification of another 12 related genes (KLK4-KLK15) within and adjacent to the original human KLK locus (KLK1-3) on chromosome 19q13.4. The structural organisation and size of these new genes is similar to that of other KLK genes except for additional exons encoding 5' or 3' untranslated regions. Moreover, many of these genes have multiple mRNA transcripts, a trait not observed with rodent genes. Unlike all other kallikreins, the KLK4-KLK15 encoded proteases are less related (25-44%) and do not contain a conventional kallikrein loop. Clusters of genes exhibit high prostatic (KLK2-4, KLK15) or pancreatic (KLK6-13) expression, suggesting evolutionary conservation of elements conferring tissue specificity. These genes are also expressed, to varying degrees, in a wider range of tissues suggesting a functional involvement of these newer human kallikrein proteases in a diverse range of physiological processes.

Plasma cytokine parameters and mortality in patients with chronic heart failure

BACKGROUND

Inflammatory immune activation is an important feature in chronic heart failure (CHF). Little is known about the prognostic importance of tumor necrosis factor-alpha (TNF-alpha), soluble TNF-receptor 1 and 2 (sTNF-R1/sTNF-R2), interleukin-6 (IL-6), and soluble CD14 receptors (sCD14) in CHF patients.

METHODS AND RESULTS

In 152 CHF patients (age 61+/-1 years, New York Heart Association [NYHA] class 2.6+/-0.1, peak VO(2) 17.3+/-0.6 mL. kg(-1). min(-1), mean+/-SEM) plasma concentrations of immune variables were prospectively assessed. During a mean follow-up of 34 months (>12 months in all patients), 62 patients (41%) died. Cumulative mortality was 28% at 24 months. In univariate analyses, increased total and trimeric TNF-alpha, sTNF-R1, and sTNF-R2 (all P</=0.0001), sCD14 (P=0.0007), and IL-6 (P=0.005) predicted 24-month mortality. With multivariate analysis and receiver operating characteristics, sTNF-R1 emerged among all cytokine parameters as the strongest and most accurate prognosticator in this CHF population, regardless of follow-up duration and independently of NYHA class, peak VO(2), VE/VCO(2) slope, left ventricular ejection fraction, and wasting (P<0.001). The receiver operating characteristic area under the curve for sTNF-R1 was greater than for sTNF-R2 at 6, 12, and 18 months (all P<0.05).

CONCLUSIONS

sTNF-R1 was the strongest and most accurate prognosticator, independent of established markers of CHF severity. Assessment of sTNF-R1 may be useful in identifying patients who are at high risk of death and in monitoring patients undergoing anti-TNF-alpha treatment.

Delay in calling for help during myocardial infarction: reasons for the delay and subsequent pattern of accessing care

OBJECTIVE

To determine the reasons for delay in calling for help during acute myocardial infarction and the reasons for choice of first medical contact.

DESIGN

Review of routine medical records and one to one semi-structured interviews.

SETTING

Community survey in city of Glasgow, north of the river Clyde.

PATIENTS

228 men and 85 women aged between 25 and 65 years, respectively, who survived acute myocardial infarction between October 1994 and December 1996.

RESULTS

Only 25% of the subjects made a call for help within one hour of the onset of coronary symptoms; in 40% the delay was greater than four hours. Symptoms were not recognised as coronary in origin in the majority of cases. In all cases where delay was more than one hour the main reasons for the delay were thinking that symptoms would go away or that they were not serious. Requesting the attendance of a general practitioner was the first course of action in the majority of cases (55%); the main reason given was that the patient believed this should always be the first course of action. Reluctance to call the emergency services reflected the belief that the symptoms were not serious enough to warrant an ambulance.

CONCLUSIONS

Strategies to reduce patient delay times in this deprived urban population must focus on educating the public on the recognition and diversity of coronary symptoms and the benefits of presenting promptly to hospital by way of the emergency ambulance service.

Superiority of endothelin-1 over norepinephrine in exercise-induced alterations of the conduit artery tone of the non-exercised arm in patients with chronic heart failure

This study is aimed at examining the relative importance of norepinephrine and endothelin-1 in treadmill exercise-induced changes in brachial arterial tone of the non-exercised arm in patients with chronic heart failure (CHF). Brachial artery diameter and blood flow were measured before and after exercise in eight healthy volunteers and 18 patients with stable chronic heart failure by high-resolution ultrasound. Maximal exercise resulted in brachial artery dilatation in controls (4.42+/-0.39 vs. 4.77+/-0.39 mm; P<0. 0001) in contrast to constriction seen in the patients (5.27+/-0.67 vs. 5.12+/-0.66 mm; P=0.07). Both groups demonstrated a significant increase in blood flow after exercise. The pre-exercise (2.83+/-0.76 vs. 1.69+/-0.15 pmol/l; P=0.0004), post-exercise (4.15+/-1.5 vs. 2. 02+/-0.34 pmol/l; P=0.0004) and the percent increase (47.15+/-32.5 vs. 19.0+/-10.5%; P=0.02) in endothelin-1 levels were significantly greater in patients than in controls. In contrast to endothelin-1, the exercise-induced percent increase in norepinephrine was greater in controls than patients (100.7+/-51.8 vs. 49.8+/-43.4%; P=0.01). The percent change in the diameter of the brachial artery in response to maximal exercise was significantly correlated to pre- (r=0.634; P=0.003) and post-exercise (r=0.467; P=0.05) endothelin-1 levels in patients but not in controls [pre-exercise (r=0.07; P=0. 86), post-exercise (r=0.310; P=0.47)]. The change in the diameter of the brachial artery did not correlate with pre- or post-exercise plasma norepinephrine levels in either group. These findings suggest that endothelin-1 is potentially more important than norepinephrine in contributing exercise-induced brachial artery constriction in patients with chronic heart failure.

Treatment with nasal CPAP decreases automobile accidents in patients with sleep apnea

We studied 50 consecutive patients to test the hypothesis that successful treatment of obstructive sleep apnea with nasal continuous positive airway pressure (nasal CPAP) will decrease automobile accidents in patients with sleep apnea. Thirty-six (72%) of the patients reported using nasal CPAP regularly during 2 yr. Fourteen patients reported they had not used CPAP during 2 yr. The patients with sleep apnea in this study had a higher automobile crash rate than all drivers in the state of Colorado (0.07 versus 0. 01 crash per driver per year, p < 0.02). Patients who were treated with nasal CPAP had a lower crash rate while being treated than before treatment (0.07 versus 0 crash per driver per year, p < 0.03). Untreated patients with sleep apnea continued to have a high crash rate (0.07 crash per driver before and after diagnosis). Drivers with sleep apnea were reluctant to report their automobile crashes, for the drivers in this study reported only one-third of the crashes in which they were involved. This is the first study to confirm with traffic records that patients with sleep apnea have fewer automobile crashes while being treated with nasal CPAP.

Plasma homocysteine concentrations and risk of coronary heart disease in UK Indian Asian and European men

BACKGROUND

Reasons for the increase in mortality due to coronary heart disease (CHD) in UK Indian Asians are not well understood. In this study, we tested the hypotheses that elevated plasma homocysteine concentrations are a risk factor for CHD in Indian Asians, and explain part of their increased CHD risk, compared with Europeans.

METHODS

We undertook two parallel case-control studies, one in Europeans and one in Indian Asians. We recruited 551 male cases (294 European, 257 Indian Asian) and 1025 healthy male controls (507 European, 518 Indian Asian). Fasting and post-methionine load homocysteine, vitamin B12 and folate concentrations, and conventional CHD risk factors were measured.

FINDINGS

Fasting homocysteine concentrations were 8% higher (95% CI 3-14) in cases compared with controls, in both ethnic groups. The odds ratio of CHD for a 5 micromol/L increment in fasting plasma homocysteine was 1.3 (1.1-1.6) in Europeans and 1.2 (1.0-1.4) in Indian Asians. The association between fasting plasma homocysteine and CHD was independent of conventional CHD risk factors in both ethnic groups. Post-load homocysteine concentrations were not significantly different in cases compared with controls. Among the controls, fasting homocysteine concentrations were 6% (2-10) higher in Indian Asians than in Europeans. From the results we estimate that elevated homocysteine may contribute to twice as many CHD deaths in Indian Asians, compared with Europeans. The differences in homocysteine concentrations between the two ethnic groups were explained by lower vitamin B12 and folate levels in Asians.

INTERPRETATION

Plasma homocysteine is a novel and independent risk factor for CHD in Indian Asians, and may contribute to their increased CHD risk. Raised homocysteine concentrations in Indian Asians may be related to their reduced vitamin B12 and folate levels, implying that the increased CHD risk in this group may be reduced by dietary vitamin supplementation.

Private sector worksite health promotion programs in Missouri: a comparison with national survey findings and Healthy People recommendations

Questionnaries with 22 multiple-choice questions were mailed to a random sample of 450 Missouri employers with 250 or more employees to determine the prevalence and types of workplace health promotion programs; 262 (58%) responded. Only 34% of the responding companies offered any kind of program and 65% of these offered only awareness programs, but most offered programs on all 18 topics listed in the questionnaire; 48% had a full-time program manager, 79% had some form of evaluation, and 36% had some form of financial incentives.

Patient perceptions of rheumatoid arthritis

Rheumatoid arthritis is rarely seen as a serious public health issue, yet it is the single largest cause of disability in the UK (Badley and Tennant 1993). In this qualitative study patients were interviewed about the physical and social effects of the disease.

Acute right ventricular restrictive physiology after repair of tetralogy of Fallot: association with myocardial injury and oxidative stress

BACKGROUND

Acute right ventricular (RV) restrictive physiology after tetralogy of Fallot repair results in low cardiac output and a prolonged stay in the intensive care unit (ICU). However, its mechanism remains uncertain.

METHODS AND RESULTS

In the first 24 hours after tetralogy of Fallot repair (n=11 patients), serial prospective measurements were performed of cardiac troponin T, indexes of NO production (NO(2)(-) and NO(3)(-) combined as NOx), and iron metabolism and antioxidants. RV diastolic function was assessed by transthoracic Doppler echocardiography. Patients who had a long stay in the ICU were characterized by restrictive RV physiology (nonrestrictive group [n=7]: 3.0+/-0.6 days [mean+/-SD]; restrictive group [n=4]: 10.7+/-3.1 days). Troponin T peak concentration and the area under its concentration-time curve (AUC) were higher in the restrictive RV group (peak: restrictive group 17. 0+/-2.8 microg/L, nonrestrictive group 10.4+/-4.6 microg/L, P<0.03; AUC: restrictive group 268.8+/-73.6 microg. h(-1). L(-1), nonrestrictive group 136.2+/-48.3 microg. h(-1). L(-1), P<0.03). Plasma NOx/creatinine concentrations were higher in the restrictive group than the nonrestrictive group at 2 hours after bypass (restrictive group 1.3+/-0.4, nonrestrictive group 0.8+/-0.2; P=0. 04) but were similar by 24 hours. Iron loading peaked 2 to 10 hours after bypass and was more severe in the restrictive group (peak transferrin saturation: restrictive group 83.9+/-13.0%, nonrestrictive group 58.3+/-16.2%, P=0.05; minimum total iron-binding capacity: restrictive group 0.59+/-0.21%, nonrestrictive group 0.76+/-0.06%, P=0.04; minimum iron-binding antioxidant activity to oxyorganic radicals: restrictive group 9. 5+/-22.4%, nonrestrictive group 50.6+/-11.4%, P=0.01).

CONCLUSIONS

After tetralogy of Fallot repair, acute restrictive RV physiology is associated with greater intraoperative myocardial injury and postoperative oxidative stress with severe iron loading of transferrin.

Tourniquet inflation during arthroscopic knee ligament surgery does not increase postoperative pain

PURPOSE

A double-blind clinical trial was conducted to determine the effect of inflation of a thigh tourniquet during anterior cruciate ligament repair on arthroscopic visibility, duration of procedure, postoperative pain and opioid consumption.

METHODS

Thirty patients were randomly allocated into two groups; Group I had the thigh tourniquet inflated during surgery whereas the tourniquet was not inflated in Group II patients. All patients received standardized general anesthesia and postoperative pain management. Supplemental analgesia was provided with i.v. morphine via a patient-controlled analgesia (PCA) apparatus. Verbal pain rating scores (0-10) were obtained after surgery.

RESULTS

Arthroscopic visibility was impaired in Group II patients (P < 0.0001), but this was ameliorated by increased irrigation flow or addition of epinephrine. Duration of surgery was similar in both groups. There was no difference between groups in postoperative morphine consumption (9.8 +/- 7.1 mg in Group I vs 11.4 +/- 10.2 mg in Group II) or in postoperative pain scores between groups.

CONCLUSION

Inflation of a thigh tourniquet did not result in increased pain or opioid consumption after arthroscopic ACL surgery. Arthroscopic visibility was somewhat impaired in some patients without the use of tourniquet. Finally, the duration of the surgical procedure was not increased in patients where the tourniquet was not inflated during the ACL repair.

Cytokines and neurohormones relating to body composition alterations in the wasting syndrome of chronic heart failure

BACKGROUND

Chronic heart failure is one of a number of disorders associated with the development of a wasting syndrome. The precise mechanisms of this remain unknown, but previous studies have suggested a role for immune and neurohormonal factors.

METHODS

We aimed to investigate in detail the differences in body composition (dual X-ray absorptiometry) and the relationship to candidate biochemical factors of the immune, neurohormonal and metabolic systems in 15 healthy controls, 36 stable non-cachectic and 18 cachectic patients with chronic heart failure.

RESULTS

Non-cachectic patients showed reduced leg lean tissue (-9.1%, P<0.01) compared to controls. Cachectic patients had significantly reduced lean (-21.0% vs controls, -19.9% vs non-cachectics), fat (-33.0% vs controls, -37. 0% vs non-cachectics) and bone tissue (-17.5% vs controls, -15.9% vs non-cachectics) (all P<0.0001). Cachectic patients showed a significantly increased cortisol/dehydroepiandrosterone ratio (+203% vs controls, P<0.0001; +89% vs non-cachectics, P=0.0011) and increased cytokine levels (TNF-alpha, soluble TNF-receptor 1, interleukin-6). The levels of catabolic hormones and cytokines correlated significantly with reduced muscle and fat tissue content and reduced bone mass.

CONCLUSION

Peripheral loss of muscle tissue is a general finding in chronic heart failure. The wasting in cardiac cachexia affects all tissue compartments and is significantly related to neurohormonal and immunological abnormalities.

Intraoperative cardiac troponin T release and lactate metabolism during coronary artery surgery: comparison of beating heart with conventional coronary artery surgery with cardiopulmonary bypass

OBJECTIVE

To compare cardiac troponin T release and lactate metabolism in coronary sinus and arterial blood during uncomplicated coronary grafting on the beating heart with conventional coronary grafting using cardiopulmonary bypass.

DESIGN

A prospective observational study with simultaneous sampling of coronary sinus and arterial blood: before and 1, 4, 10, and 20 minutes after reperfusion for analysis of cardiac troponin T and lactate. Cardiac troponin T was also analysed in venous samples taken 3, 6, 24, 48, and 72 hours after surgery.

SETTING

Cardiac surgical unit in a tertiary referral centre.

PATIENTS

18 patients undergoing coronary grafting on the beating heart (10 single vessel and eight two-vessel grafting) and eight undergoing two-vessel grafting with cardiopulmonary bypass.

RESULTS

Cardiac troponin T was detected in coronary sinus blood in all patients by 20 minutes after beating heart coronary artery surgery before arterial concentrations were consistently increased. Peak arterial and coronary sinus cardiac troponin T values on the beating heart during single (0.03 (0 to 0. 05) and 0.09 (0.07 to 0.16 microg/l, respectively) and two-vessel grafting (0.1 (0.07 to 0.11) and 0.19 (0.14 to 0.25) microg/l) were lower than the values obtained during cardiopulmonary bypass (0.64 (0.52 to 0.72) and 1.4 (0.9 to 2.0) microg/l) (p < 0.05). The area under the curve of venous cardiac troponin T over 72 hours for two-vessel grafting on the beating heart was less than with cardiopulmonary bypass (13 (10 to 16) v 68 (26 to 102) microg.h/l) (p < 0.001). Lactate extraction began within one minute of snare release during beating heart coronary surgery while lactate was still being produced 20 minutes after cross clamp release following cardiopulmonary bypass.

CONCLUSIONS

Lower intraoperative and serial venous cardiac troponin T concentrations suggest a lesser degree of myocyte injury during beating heart coronary artery surgery than during cardiopulmonary bypass. Oxidative metabolism also recovers more rapidly with beating heart coronary artery surgery than with conventional coronary grafting. Coronary sinus cardiac troponin T concentrations increased earlier and were greater than arterial concentrations during beating heart surgery, suggesting that this may be a more sensitive method of intraoperative assessment of myocardial injury.

Comparison of the scope of allopathic and osteopathic medical school health promotion programs for students

PURPOSE

To compare the number and scope of health promotion programs for students in allopathic and osteopathic medical schools in the U.S. and Canada.

DESIGN

A one-time cross-sectional survey design was applied in this study.

SETTING

This study was conducted in 141 accredited allopathic and 17 accredited osteopathic medical schools.

SUBJECTS

A total of 158 representatives from the allopathic and osteopathic medical schools participated in this study. The response rate for the survey was 100%.

MEASURES

A structured telephone interview was conducted to survey representatives from the medical schools. The survey contained 85 multiple-choice questions organized into four sections: administrative characteristics, types of institutional and health promotion program policies, participation incentives and facilities, and type/scope of health promotion program activities. Chi-square analysis was used to analyze survey variables by type of medical education and level of intervention.

RESULTS

Of the 158 medical schools, only 20% (n = 32) provided a health promotion program for students. Although osteopathic institutions (29.4%) had a greater percentage of programs than allopathic schools (19.2%), there was no significant difference in scope of program offerings by type of medical education. Allopathic programs offered exercise and nutrition/weight management significantly more often and at a higher level of intervention. Lastly, allopathic programs had significantly more monetary resources available for programming. Following prudent research protocol, investigators should be mindful of the limitations of this study. In this study, some school representatives chose not to answer personnel- and finance-related questions. Additionally, because of the self-report nature of the survey, the responses given to the questions may not have been accurate.

CONCLUSION

Allopathic and osteopathic medical school health promotion programs for students were very similar in scope.

Diagnosis of cystic fibrosis related diabetes: a selective approach in performing the oral glucose tolerance test based on a combination of clinical and biochemical criteria

BACKGROUND

Cystic fibrosis related diabetes (CFRD) has become increasingly common with the increasing longevity of patients with cystic fibrosis. The diagnosis of CFRD is important as its development may lead to a clinical deterioration which may be reversed with treatment. The oral glucose tolerance test (OGTT) is the method of choice in the diagnosis of CFRD, but performing OGTTs on all patients is inconvenient for patients and labour intensive for staff. The aim of this study was to identify a more selective approach in performing OGTTs in the diagnosis of CFRD based on the use of a combination of clinical and biochemical criteria.

METHODS

Clinically stable adult patients with cystic fibrosis not known to be diabetic attending the Royal Brompton Hospital Cystic Fibrosis Clinic for their annual review were invited to return within a month to have an OGTT. The result of the OGTT was compared with the results of tests performed during the annual review. The sensitivities and specificities of various methods used in the screening or diagnosis of CFRD were determined using OGTT as the "gold standard" diagnostic method. The combination of clinical and biochemical criteria which resulted in the highest sensitivity and specificity in the diagnosis of CFRD was determined.

RESULTS

Between August 1996 and May 1997 122 patients became eligible for the study, 91 of whom agreed to take part. The number of patients with normal, impaired, and diabetic glucose tolerance was 58 (64%), 21 (23%), and 12 (13%), respectively. When used alone, abnormal glycosylated haemoglobin (HbA1c) was found to have the highest sensitivity (83%; 95% CI 62 to 100) in the diagnosis of CFRD. The combination of an abnormal random blood glucose and/or abnormal HbA1c and/or symptoms of hyperglycaemia or weight loss was found to have the highest sensitivity (92%; 95% CI 76 to 100) in the diagnosis of CFRD. The specificity of this combination in the diagnosis of CFRD was 79% (95% CI 70 to 88). By selectively performing OGTTs in patients with one or more of the criteria cited above, 11 of the 12 patients with OGTT defined diabetes would have been identified.

CONCLUSIONS

Patients with cystic fibrosis already have to undergo a large number of routine investigations. The selective approach in performing OGTTs described here has the potential to identify the majority of patients with CFRD without the need to perform this investigation on all patients. This approach is likely to be welcomed by patients and will lead to significant savings in terms of time and resources for patients and staff. Further larger studies are warranted to validate this selective approach in the diagnosis of CFRD.

Dopamine clearance in critically ill patients

OBJECTIVE

To examine the validity of the low-dose "renal" dopamine regimen in critically ill patients by investigating the steady-state clearance of dopamine.

DESIGN

A prospective clinical study.

SETTING

Teaching hospital intensive care unit.

PATIENTS

48 haemodynamically stable patients receiving a dopamine infusion.

INTERVENTIONS

Sampling of arterial blood and dopamine infusates.

MEASUREMENT AND RESULTS

Plasma and infusate dopamine levels were measured by liquid chromatography with electrochemical detection. Steady-state clearance was determined by dividing the actual infusion rate by the steady-state plasma concentration. Dopamine clearance for the whole group was 46.4 +/- 35.9 ml/kg per min (mean +/- SD), which is significantly lower than 70 +/- 15.2 ml/kg per min reported for elective surgical patients (p = 0.01). Twelve patients with renal dysfunction had significantly lower dopamine clearances (36 +/- 16.6 ml/kg per min) than the remaining 36 patients (61 +/- 38.5 ml/kg per min, p = 0.022). There was a very poor correlation between plasma dopamine level and infusion rate for the group as a whole (r = 0.47), and this worsened (r = 0.31) when only those patients on a "renal" dose of 2-5 microg/kg per min were considered (n = 30).

CONCLUSION

Plasma dopamine clearance is lower in critically ill patients and there is a large interindividual variation. It is therefore impossible to predict the plasma level from the infusion rate. Consequently, the concept of a selective renovascular low-dose dopamine infusion is invalid in critically ill patients.

Intraoperative release of troponin T in coronary venous and arterial blood and its relation to recovery of left ventricular function and oxidative metabolism following coronary artery surgery

OBJECTIVE

To investigate the intraoperative release of troponin T during uncomplicated coronary artery surgery and to determine its relation to ischaemic time and to recovery of left ventricular function and oxidative metabolism.

DESIGN

A prospective observational study.

SETTING

Cardiac surgical unit in a tertiary referral centre.

METHODS

Troponin T, creatine kinase, and lactate were analysed from arterial and coronary sinus samples taken before operation, and 1, 4, 6, 10, 20, 35, and 45 minutes after cross clamp release. Net myocardial troponin T release and lactate extraction were derived from their respective arteriovenous differences. Haemodynamic measurements were made using a thermodilution pulmonary artery catheter.

PATIENTS

45 patients, mean (SD) age 62 (9) years, with two or three vessel coronary artery disease and chronic stable angina undergoing routine coronary artery surgery.

RESULTS

Before operation, troponin T concentrations were not raised, but within one minute of cross clamp release they increased progressively in both coronary sinus and arterial blood for the entire 45 minutes of reperfusion studied. Coronary sinus troponin T concentrations were consistently higher than arterial concentrations at all time points (p < 0.001), indicating net troponin T release by the myocardium. Peak net troponin T release and area under the curve of net troponin T release correlated closely with ischaemic time (r = 0.58 and r = 0.61, p < 0.0001 for both). Area under the curve of arterial troponin T concentration was also significantly correlated with ischaemic time (r = 0.44, p < 0.01). Patients with cross clamp times longer than 72 minutes (upper quartile for ischaemic time) had greater troponin T release, delayed reversion to lactate extraction, and lower left ventricular stroke work index three hours after surgery, compared with patients who had short (< 50 minutes, lower quartile) and intermediate (51-71 minutes, interquartile) cross clamp times. Peak net troponin T release and area under the curve of arterial troponin T concentration were inversely correlated with left ventricular stroke work index three hours after surgery (r = -0.57, r = -0.38, p < 0.01).

CONCLUSIONS

Troponin T concentrations increased in every patient after cross clamp release, and were consistently higher in coronary sinus blood than in arterial blood, indicating net myocardial release of troponin T during the period of reperfusion. Intraoperative net troponin T release has functional significance, as it is closely related to ischaemic time and reflects delayed recovery of left ventricular function and oxidative metabolism; therefore, its measurement may contribute to the perioperative assessment of myocardial injury sustained during coronary artery surgery.

Rater reliability of Fahn's tremor rating scale in patients with multiple sclerosis

OBJECTIVE

Assessment of movement disorders in patients with multiple sclerosis (MS) is difficult because of the complex nature of the movement disorders. The aim of this study was to determine the reliability of Fahn's Tremor Rating Scale (FTRS) in assessing movement disorders in patients with MS.

METHOD

Videos were made of 10 patients with MS showing their rest, postural, action/intention, and goal-related movement disorders as well as their performance of spirometry, a volumetric task, and timed functional tasks. Ratings of tremor were carried out by one rater on two occasions 3 months apart and by 8 raters on one occasion using FTRS.

RESULTS

Intrarater reliability was generally very good, with no significant "drift" in ratings over time. Interrater reliability was generally good, with some variation in interpretation of scoring criteria that may reflect raters' backgrounds.

CONCLUSION

The FTRS is a reliable and potentially useful tool with which to assess movement disorders in patients with MS.

Deficient insulin-like growth factor I in chronic heart failure predicts altered body composition, anabolic deficiency, cytokine and neurohormonal activation

BACKGROUND

Recent studies of growth hormone supplementation in chronic heart failure have been associated with variable results. Acquired abnormalities of biochemical parameters of the growth hormone insulin-like growth factor I axis have been associated with severe chronic heart failure. There are suggestions of an acquired growth hormone resistance with deficient insulin-like growth factor I in some patients.

OBJECTIVES

Therefore, we set out to investigate the clinical and functional status and the degree of cytokine and neurohormonal alteration of chronic heart failure patients with deficient insulin-like growth factor I responses.

METHODS

Patients with chronic heart failure were divided into two groups according to their insulin-like growth factor I levels (classified according to the manufacturer's assay range in normal controls): low insulin-like growth factor I <104 (n = 20; 89 +/- 9.6 ng/ml), and normal/high >104 ng/ml (n = 32; 169 +/- 52 ng/ml). Between groups there was no difference in age (low versus high: 65.3 +/- 12.1 versus 61.6 +/- 9.1 years, p = 0.21), body mass index, aerobic capacity (peak oxygen consumption: low versus high: 15.5 +/- 5.2 versus 17.3 +/- 6.3 mL/kg/min, p = 0.23), left ventricular ejection fraction, New York Heart Association classification.

RESULTS

During quadriceps strength testing, patients with low insulin-like growth factor I had reduced absolute strength (-24%), and strength per unit area muscle (- 14%) than patients with normal/high insulin-like growth factor I. Leg muscle cross-sectional area was lower in the low insulin-like growth factor I group (-12% and -13% for right and left legs, respectively). These alterations were accompanied by increased levels of growth hormone (+145%), tumor necrosis factor-alpha (+46%), cortisol/ dehydroepiandrosterone ratio (+60%), noradrenaline (+49%) and adrenaline (+136%) (all at least p < 0.05).

CONCLUSIONS

Patients with low insulin-like growth factor I levels show signs of altered body composition, cytokine and neuroendocrine activation, to a greater extent than patients with normal/high levels.

Can C reactive protein or troponins T and I predict outcome in patients with intractable unstable angina?

OBJECTIVE

To determine whether a single blood test for the measurement of C reactive protein, or troponin I or T concentrations could be used to stratify patients with intractable unstable angina awaiting transfer for coronary angiography by correlating these values with coronary anatomy and transient myocardial ischaemia.

DESIGN

Prospective study.

SETTING

Tertiary cardiac unit.

PATIENTS

All patients admitted to their local hospital with ischaemic chest pain, uncontrolled by medical treatment, in whom acute myocardial infarction had been excluded by serial measurement of creatine kinase and lack of Q waves on ECG.

INTERVENTION

Coronary angiography and ST segment monitoring for 24 hours.

MAIN OUTCOME MEASURES

Concentrations of C reactive protein, troponins T and I, coronary anatomy, presence of transient myocardial ischaemia.

RESULTS

Median C reactive protein, troponin I, and troponin T concentrations were 17.1 mg/dl (4.8 to 203.9), 0.05 microgram/l (0 to 7.8), and 0.0 microgram/l (0 to 2.51), respectively. Seven patients (10%) had normal coronaries and 14, 20, and 31 had one, two, or three vessel coronary disease, respectively. Nineteen (26%) had transient myocardial ischaemia, 33 (46%) had complex lesion morphology, and six (8%) had intracoronary thrombus. Of the three markers, troponin T alone was higher in patients with multivessel disease (p < 0.05) and in those with transient myocardial ischaemia (p < 0.05), but there was no significant relation between C reactive protein, troponin T or I and lesion morphology or thrombus.

CONCLUSIONS

In patients transferred to a tertiary centre with intractable chest pain, C reactive protein and troponin I are not predictive of transient myocardial ischaemia or lesion morphology, both of which are surrogate markers of outcome. Troponin T is, however, raised in patients with multivessel disease or transient myocardial ischaemia. These serum protein assays cannot be used to stratify the risk of patients with unstable angina who are awaiting transfer to the tertiary centre.

Gastro-intestinal protein loss in late survivors of Fontan surgery and other congenital heart disease

AIMS

Protein losing enteropathy is a serious complication of Fontan surgery. The aim of this study was to investigate gastro-intestinal protein loss in adults with congenital heart disease, both with and without Fontan surgery, and to correlate findings with systemic venous pressure.

METHODS AND RESULTS

Forty eight patients were studied. The first group included adult survivors of Fontan surgery. The second and third groups were control patients with congenital heart disease who had not had Fontan surgery and had either normal or chronically elevated systemic venous pressure. Gastro-intestinal protein loss was assessed by measurement of faecal alpha-1-antitrypsin. Faecal alpha-1-antitrypsin levels were significantly higher in the Fontan group (0.55 +/- 0.15 mg. g-1 faeces, P = 0.002) and the control group with chronically elevated venous pressure (0.60 +/- 0.30 mg. g-1 faeces, P < 0.001) compared to the controls with normal venous pressure (0.29 = 0.12 mg. g-1 faeces). Of the 15 subjects who were found to have increased gastro-intestinal protein loss, only four had clinical protein-losing enteropathy. The degree of gastro-intestinal protein loss correlated significantly with venous pressure (P = 0.01) and with serum aspartate transaminase (P = 0.04).

CONCLUSION

Increased gastro-intestinal protein loss is common in this select group of late survivors of Fontan surgery and in other subjects with congenital heart disease and chronic elevation of systemic venous pressure, and was present in patients who did not have protein-losing enteropathy. Increased faecal alpha-1-antitrypsin is an important finding in these patients as intervention at this stage, before the onset of florid protein-losing enteropathy, might prevent the development of further complications.

Treatment of milrinone-associated tachycardia with beta-blockers

PURPOSE

To describe a case of milrinone-associated tachycardia that was successfully treated with two beta-blockers.

CLINICAL FEATURES

A 74-yr-old male patient underwent elective abdominal aortic aneurysm repair under combined epidural/general anaesthesia. He had a history of alcohol abuse, controlled hypertension and ischaemic heart disease. Postoperatively, the patient had persistent sinus tachycardia that was initially unsuccessfully treated with metoprolol. Subsequently, the patient's blood pressure and cardiac index decreased with an associated increase in pulmonary artery pressure. Analysis of the ST-segment revealed no evidence of myocardial ischaemia or infarction. These haemodynamic changes were treated with milrinone which exacerbated the baseline tachycardia without adverse blood pressure response. The subsequent administration of beta-blockers (esmolol and metoprolol) was successful in controlling the heart rate response to milrinone without adversely affecting the patient's haemodynamic profile.

CONCLUSION

This report demonstrates the efficacy of esmolol and metoprolol for the treatment of milrinone-associated tachycardia, without compromising the haemodynamic effects of milrinone.

Log-jam in acid-base education and investigation: why make it so difficult?

Medical students frequently have difficulty in interpreting acid-base data particularly when pH values are used. The difficulty persists when students qualify and has implications for the safe management of patients who require investigation of acid-base status. Simplification of tuition is required together with a change of practice in the reporting of acid-base data by the laboratories. To improve understanding, we recommend that the teaching and reporting of acid-base status should be changed to use [H+] instead of pH, and a greater emphasis placed on the logical interpretation of primary measurements--that is [H+] and PCO2--with less reliance on derived variables.

Plasma brain natriuretic peptide concentrations in patients with chronic mitral regurgitation

BACKGROUND AND AIMS OF THE STUDY

Patients with chronic mitral regurgitation (MR) are often referred for surgery only after irreversible left ventricular (LV) dysfunction has developed. Our aim was to determine whether plasma brain natriuretic peptide (BNP) concentrations could serve as a marker for early LV dysfunction in this condition.

METHODS

Twenty-two patients with isolated chronic MR and echocardiographic evidence of at least moderate regurgitation were studied.

RESULTS

Plasma BNP concentrations were significantly higher in patients than in normal volunteers (20.85 +/- 16.9 versus 3.37 +/- 0.9 pmol/l; p = 0.007). Concentrations increased with increasing severity of symptoms and were highest in those in NYHA class IV, but did not correlate with LV dimensions, fractional shortening or left atrial size. Of note, two asymptomatic patients with high BNP concentrations were referred for surgery within the 12-month follow up period due to symptom progression.

CONCLUSIONS

Plasma BNP concentrations are elevated in most patients with isolated chronic MR, including those who are asymptomatic with normal LV dimensions. The significance of these findings is uncertain, but they suggest that changes in ventricular physiology occur early in the disease process and before they can be detected echocardiographically. Longitudinal studies are required to determine if patients with high BNP levels have an adverse prognosis and if this can be altered by earlier surgical intervention.

Ischaemic preconditioning reduces troponin T release in patients undergoing coronary artery bypass surgery

OBJECTIVE

To investigate whether ischaemic preconditioning could reduce myocardial injury, as manifest by troponin T release, in patients undergoing elective coronary artery bypass surgery.

DESIGN

Randomised controlled trial.

SETTING

Cardiothoracic unit of a tertiary care centre.

PATIENTS

Patients with three vessel coronary artery disease and stable angina admitted for first time elective coronary artery bypass surgery were invited to take part in the study; 33 patients were randomised into control or preconditioning groups.

INTERVENTION

Patients in the preconditioning group were exposed to two additional three minute periods of myocardial ischaemia at the beginning of the revascularisation operation, before the ischaemic period used for the first coronary artery bypass graft distal anastomosis.

MAIN OUTCOME MEASURE

Serum troponin T concentration at 72 hours after cardiopulmonary bypass.

RESULTS

The troponin T assays were performed by blinded observers at a different hospital. All patients had undetectable serum troponin T (< 0.1 microgram/l) before cardiopulmonary bypass, and troponin T was raised postoperatively in all patients. At 72 hours, serum troponin T was lower (P = 0.05) in the preconditioned group (median 0.3 microgram/l) than in the control group (median 1.4 micrograms/l).

CONCLUSIONS

The direct application of a preconditioning stimulus in clinical practice has been shown, for the first time, to protect patients against irreversible myocyte injury.

Effects of age and ischemic times on biochemical evidence of myocardial injury after pediatric cardiac operations

INTRODUCTION

The vulnerability of pediatric myocardium to ischemia is poorly documented in the clinical setting.

METHODS

Serial measurements of serum concentrations of myoglobin, the MB isoenzyme of creatine kinase, and cardiac troponins T and I and their respective areas under the curve were obtained, with particular reference to age and ischemic time, in 80 children undergoing cardiac operations. Sixteen (the control group) did not require cardiopulmonary bypass and 64 did.

RESULTS

In the control group there were increases (p < 0.01) in myoglobin and creatine kinase MB isoenzyme but no increase in cardiac troponin T or I; by contrast, the group treated with cardiopulmonary bypass had significant increases in all four markers but with differing temporal patterns. Younger age (especially < 12 months) was a highly significant explanatory variable only for the release of cardiac troponins T and I, and ischemic time was a significant explanatory variable for the release of creatine kinase MB isoenzyme, cardiac troponins T and I, but not myoglobin. In comparison with previous studies in adults, creatine kinase MB and cardiac troponin T concentrations were three times greater in children than in adults.

CONCLUSIONS

This study supports the specificity of cardiac troponins T and I as markers of myocardial injury after pediatric cardiac operations and defines the importance of age and ischemic time in determining their release. In comparison with previous data in adults, our results raise the possibility that the pediatric heart may be more vulnerable to the effects of ischemia and reperfusion. Cardiac troponins will permit comparison of new myocardial protective strategies or other potentially therapeutic myocardial interventions.

Does activated neutrophil depletion on bypass by leukocyte filtration reduce myocardial damage? A preliminary report

An important factor in the production of myocardial damage following cardiopulmonary bypass in the creation of oxygen derived free radicals. Few sources for these radicals have been identified but experimentally activated neutrophils are known to release free radical which contribute to myocyte necrosis. The aim of this pilot study was to identify whether, by depleting patients of leukocytes and particularly neutrophils on bypass, a better degree of myocardial protection could be observed using specific identifiers of myocardial damage. Ten patients undergoing urgent coronary artery bypass for unstable angina with impaired left ventricular function were leuko-depleted using a PALL medical leukocyte filter in the extra corporeal circulation together with leukocyte depletion of all transfused blood. A similar group of matched controls had only an arterial line filter without leukodepletion. All patients were operated by one surgeon using identical techniques of intermittent cross clamping and fibrillation at moderate hypothermia. Full blood count, Glutathione, Troponin T and CPK/MB were measured before, during and at identified intervals up to 72 hour after bypass. Preliminary results show little change in the total leukocyte count but the Troponin T and CPK/MB values were lower in the filtered group than in the control group and an increased level of total Glutathione in the filter group showed that there was less oxidated stress on the myocardium. Currently this filter is an expensive addition to bypass surgery but these preliminary results suggest that activated neutrophil depletion on bypass may be of benefit to patients with unstable angina, impending myocardial necrosis and low ejection fraction.

Hyperchloraemic acidosis during recovery from hyperglycemic diabetic emergencies

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Vulnerability of paediatric myocardium to cardiac surgery

OBJECTIVE

Myocardial injury is an important cause of mortality and morbidity after paediatric cardiac surgery. Data obtained from studies in animals imply that juvenile myocardium is more resistant to the effects of ischaemia and reperfusion than adult myocardium but there is little confirmatory evidence in the clinical setting.

DESIGN

Prospective observational study of biochemical markers of myocardial injury in a paediatric population undergoing cardiac surgery.

SETTING

Tertiary referral centre for paediatric cardiac surgery.

PATIENTS

Forty patients undergoing paediatric cardiac surgery of varying complexity including closure of atrial and ventricular septal defects and arterial switch for simple transposition. A control group included patients undergoing thoracotomy for closure of a patent ductus arteriosus or repair of a coarctation.

INTERVENTIONS

Serial measurements of myoglobin, the MB isoenzyme of creatine kinase (CK-MB), and the highly specific markers of myocardial damage cardiac troponin T (cTnT) and I (cTnI) were made before and 1, 6, 24, and 48 to 72 hours after operation.

RESULTS

There were significant increases in myoglobin and CK-MB, but not cTnT or cTnI, in the control group. There were significant increases in the four biochemical markers in all the cardiac operations but especially in the ventricular septal defect and transposition group. Increases in CK-MB and cTnT were about five times greater than those previously reported in adult patients.

CONCLUSIONS

(i) Cardiac troponins are more specific markers of myocardial injury in paediatric cardiac surgery than myoglobin and CK-MB. (ii) Paediatric myocardium seems to be more vulnerable to injury during cardiac surgery than adult myocardium.

Leg blood flow, metabolism and exercise capacity in chronic stable heart failure

OBJECTIVES

To assess the metabolic state of skeletal muscle during exercise in patients with chronic heart failure (CHF) and relate this to exercise capacity.

BACKGROUND

During exercise in CHF, there is little relation between exercise capacity and central haemodynamic function. Skeletal muscle and limb blood flow are abnormal in CHF. We investigated the relationship between leg blood flow, metabolism and exercise capacity and ventilation in 10 patients (average age 63.3 +/- 6.0 years; 3 female) with stable CHF.

METHODS

Patients undertook maximal exercise testing. Peak oxygen consumption (VO2) and the slope of the relationship between ventilation and carbon dioxide production (VE/CO2 slope) were derived. During a supine cycle exercise test, cardiac output (CO) by Doppler echocardiography, femoral blood flow (FBF) by thermodilution, pulse and blood pressure were recorded, and radial arterial and femoral venous blood samples taken for catecholamine, lactate and potassium estimation every 3 min.

RESULTS

The average peak VO2 was 19.7 (+/- 5.2; range 11.3-29.0) ml/kg/min. The proportion of CO to the right leg increased from 0.08 (+/- 0.03) to 0.22 (+/- 0.06) (P < 0.001) at 3 min, with no further significant change thereafter. There was a liner increase in leg VO2 reaching a plateau towards peak. At peak, femoral venous saturation was 22.79% +/- 7.20%. Venous lactate and potassium were higher than arterial (P < 0.001 for each comparison). There was no correlation between exercise performance and any of the measured metabolites either in absolute measurements, expressed as change from rest to peak exercise or as arterio-venous difference. The closest correlate of leg VO2 was leg hydrogen ion production, V[H+]. Change in femoral venous lactate from rest to peak exercise correlated with VE/VCO2 slope even when calculated from before the anaerobic threshold (r = -0.80; P = 0.025).

CONCLUSIONS

In CHF, exercise capacity is not determined by individual haemodynamic events, and does not seem to be determined by the possible humoral signals we investigated. Ventilation is abnormal before anaerobic threshold, and predicts subsequent lactate rise, suggesting that skeletal muscle is the origin of excessive ventilation.

Medical education: challenges and opportunities

New curricula and educational methods are needed in medical education to take account of changes in the material taught, and the way in which education is delivered. We describe two approaches to these challenges--an internationally developed slide-text-based program and a multimedia clinical case-based CD-ROM project.

Effects of short-term supplementation with coenzyme Q10 on myocardial protection during cardiac operations

BACKGROUND

Coenzyme Q10 (CoQ10) is a naturally occurring vitamin-like substance that may have a beneficial role in ischemia-reperfusion injury. Coenzyme Q10 administered either as an additive to cardioplegia or as long-term preoperative oral supplementation has been reported to ameliorate myocardial injury after cardiac operations.

METHODS

To determine whether short-term supplementation with large doses of CoQ10 (600 mg in divided doses 12 hours before operation) was effective in myocardial protection, 20 patients with well-preserved left ventricular function (ejection fraction greater than 0.50) undergoing elective coronary revascularization were enrolled in a prospective, double-blind, placebo-controlled randomized trial. Serial concentrations of CoQ10, myoglobin, creatine kinase MD fraction, and cardiac troponin T were measured preoperatively and 1, 6, 24, 72, and 120 hours postoperatively. Efficacy of myocardial protection was also assessed by clinical outcome and serial changes in electrocardiographic indices.

RESULTS

The patient groups were similar with respect to preoperative and intraoperative characteristics. There was no significant difference in the preoperative plasma levels of CoQ10. These levels fell significantly in both groups after operation, although the magnitude of the decrease was less in the CoQ10-supplemented group (43% versus 60%). In both groups, there were significant postoperative increases in myoglobin, creatine kinase MB fraction, and cardiac troponin T. The magnitude of increases in cardiac troponin T was greater in the CoQ10-supplemented group, reaching marginal overall statistical significance (p = 0.06).

CONCLUSIONS

Short-term supplementation with large doses of CoQ10 does not lead to improved myocardial protection in patients undergoing coronary revascularization with well-preserved ventricular function and relatively short ischemic times.

Tutorial software for clinical chemistry incorporating interactive multimedia clinical cases

We have developed computer-based clinical case histories incorporating multimedia elements to aid the learning of medicine in a problem-based manner. Topics have been developed in the specialty of Clinical Biochemistry but the approach used is suitable for any branch of clinical medicine. Each topic has material aimed at medical students and also postgraduate candidates for professional examinations. A browser program is also incorporated. Emphasis is made on interaction through the case and modeling of real-life decisions in diagnosis and treatment. Advantages of the program are self-paced learning, assessment of understanding, feedback, and emphasis on deep understanding of the basic physiological and biochemical processes underlying clinical problems.

Tutorial software for clinical chemistry incorporating interactive multimedia clinical cases

We have developed computer-based clinical case histories incorporating multimedia elements to aid the learning of medicine in a problem-based manner. Topics have been developed in the specialty of Clinical Biochemistry but the approach used is suitable for any branch of clinical medicine. Each topic has material aimed at medical students and also postgraduate candidates for professional examinations. A browser program is also incorporated. Emphasis is made on interaction through the case and modeling of real-life decisions in diagnosis and treatment. Advantages of the program are self-paced learning, assessment of understanding, feedback, and emphasis on deep understanding of the basic physiological and biochemical processes underlying clinical problems.

Three-point restraints as a risk factor for chest injury in the elderly

As the number of drivers over the age of 65 years increases, new trauma patterns are emerging. The use of lap-shoulder restraints, in this population, is beginning to play an important role in new findings about their injuries. Restraint use in motor vehicle crash victims, in relation to average AIS score, ISS, and number of hospital and ICU days, was studied at a level I trauma center. The control group consisted of 100 patients between the ages of 35 and 45 years, who were involved in motor vehicle impacts (MVIs) from January 1990 through January 1992. The study group consisted of 120 patients over the age of 65 years who were involved in MVIs from January 1987 through January 1992. In the control group, restraint use was associated with a lower average AIS score--3.39 versus 7.35 for the unrestrained victims. In addition, the restrained victims spent fewer days in the ICU--0.08 versus 0.30 days for the unrestrained victims; and fewer hospital days--1.08 versus 2.0 days for the unrestrained victims. The general pattern of lower average AIS scores in restrained victims was also seen in the study group. However, in the study group, lap-shoulder belt-restrained patients had higher average AIS scores, in the chest region, than unrestrained patients--0.92 (SE 1.60) versus 0.71 (SE 1.47), respectively. These findings indicate that physicians must be aware of restraint patterns of chest injury in elderly patients. Aggressive triage criteria and vigorous pulmonary toilet, especially in patients with rib fractures, sternal fractures, and pulmonary contusions, should become integral parts of trauma resuscitation protocols in elderly patients.