Selective preoperative endoscopic retrograde cholangiography with sphincterotomy avoids bile duct exploration during laparoscopic cholecystectomy

A policy of preoperative endoscopic retrograde cholangiography (ERC) for suspected bile duct stones was used in 1507 patients considered for laparoscopic cholecystectomy in three district general hospitals. Altogether 306 patients underwent ERC, and bile duct cannulation was achieved in 276 (90%). Bile ducts were cleared by endoscopic sphincterotomy in 128 of 161 patients (79%) with proven duct stones. Laparoscopic cholecystectomy was completed in 1396 patients. Ten laparotomies were necessary for complications of laparoscopic cholecystectomy. The complication rate for endoscopic sphincterotomy/laparoscopic cholecystectomy was 2.7%, with no mortality. Overall, a combined endoscopic/laparoscopic approach succeeded in 1386 patients (92%). Fourteen patients (1%) had retained stones during a median of 14 months (range 1-42) follow up, all of which were removed by ERC/endoscopic sphincterotomy. If a policy of selective ERC before laparoscopic cholecystectomy is used for all patients with symptomatic gall stones, most will avoid an open operation and laparoscopic exploration of the bile duct is not necessary.

Sinus node reentrant tachycardia

This review article discusses the electrophysiological basis of sinus node reentry, clinical features of sinus node reentry, and the management of this uncommon tachycardia with drugs and ablative therapy. It also proposes the use of the term "sinoatrial reentrant tachycardia" for this form of tachycardia.

Subpectoral implantation of ICD generators: long-term follow-up

A nonthoracotomy surgical approach using an endocardial electrode and combined implantation of a subcutaneous patch and the implantable cardioverter defibrillator (ICD) generator in a subpectoral pocket has been described. We report the long-term follow-up results in patients undergoing implantation using this approach. The patient population consisted of 28 patients (22 men and 6 women) with a mean age of 59 +/- 12 years. The underlying heart disease consisted of coronary artery disease in 20 patients and dilated cardiomyopathy in 8 patients. Sustained ventricular tachycardia was the mode of presentation in 16 patients and sudden cardiac death in 12 patients. The mean left ventricular ejection fraction was 31% +/- 6%. The lead system consisted of an 8 French bipolar passive fixation rate sensing lead positioned at the right ventricular apex, an 11 French spring coil electrode positioned at the superior vena cava-right atrial junction (surface area 700 mm2), and submuscular placement of a large patch (surface area 28 cm2) on the anterolateral chest wall near the cardiac apex via a submammary incision. A defibrillation threshold of < or = 15 joules (J) was required for implantation. This criterion was not satisfied in five patients; thus, a limited thoracotomy was performed via the submammary incision, and the large patch was placed epicardially. The mean R wave amplitude was 12 +/- 3 mV, the mean pacing threshold was 1.0 +/- 0.5 V at 0.5 msec, and the mean defibrillation threshold was 12.6 +/- 3 J. ICD generators implanted were the Ventak-P in 17, PCD-7217 in 5, and the Cadence V-100 in 6 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Short-term effect of epidermal growth factor (EGF) on sodium and glucose cotransport of isolated jejunal epithelial cells

This study was undertaken to assess the short-term effects of EGF on sodium and glucose uptake, glucose metabolism and Na+/K(+)-ATPase activity in isolated enterocytes of rats. Jejunal cells exposed to EGF had a significantly greater total uptake of sodium compared to controls after 6 min. Kinetic analysis of glucose transport across BBMV's demonstrated similar Km values but a significant increase of the Vmax in vesicles prepared from cells first exposed to EGF as compared to controls. EGF was also associated with a significant increase in glucose metabolism of jejunal enterocytes after 15 min. The activity of Na+/K(+)-ATPase increased in jejunal enterocytes exposed to EGF. The increase in Na+/K(+)-ATPase activity of the cells following EGF exposure was not accompanied by an increase in immunodetectable total or assembled Na+/K(+)-ATPase protein. EGF's effect on enzyme activity was abolished by removing NaCl from the incubation solution, and by preincubating the enterocytes with phlorizin prior to addition of EGF. Preincubation with amiloride did not inhibit the effect of EGF on Na+/K(+)-ATPase. The results confirm that EGF promotes uptake of both sodium and glucose by the jejunal mucosal cells, and suggest the effect of EGF on glucose and sodium is mediated through the brush-border membrane glucose-sodium transporter. The increase in Na+/K(+)-ATPase activity that occurs with EGF appears to be secondary to a rise in intracellular Na+ concentration. The short-term effects of EGF on glucose and sodium transport by the small intestine may have potential therapeutic implications.

Prevalence of fetal exposure to cocaine in Toronto, 1990-1991

There has been an increasing use of cocaine in North America among women of reproductive age. The potential effects of cocaine on the fetus have raised serious concerns about the health of large numbers of children exposed in utero to the drug. Using neonatal hair and urine tests for benzoylegconine (BE), we quantified the incidence of fetal exposure to cocaine among 600 babies born in 3 nurseries in Toronto from 1990-91. A total of 37 babies (6.25%) tested positive for cocaine exposure by either hair test, urine test, or both. The hair test detected 33 cases and failed to identify 4 babies who had low urine concentrations of BE. The urine test failed to identify 76% of the cases. In downtown Toronto, the overall rate of fetal exposure to cocaine was 12.5% (25/200), significantly higher than in the 2 suburban nurseries (3%; 12/400). Babies are born with hair which has grown during the last trimester of pregnancy; hence, our analysis identifies women who have used cocaine long after they became aware of pregnancy. Our figures translate to more than 5,000 babies annually in the greater Toronto area who are cared for postnatally by mothers regularly using cocaine. Because history and urine testing during delivery fail to identify the majority of these cases, most of these children are not likely to receive the appropriate medical and social services and follow-up.

Histopathological changes following laser ablation of a left-sided accessory pathway in a human

Laser ablation was performed intraoperatively in a patient with coronary artery disease and Wolff-Parkinson-White syndrome. Histopathological evaluation of the laser ablation site revealed a transverse laser incision in the left atrial septum and mitral valve annulus. There was hemorrhage in the atrioventricular (AV) groove with interruption of a posterolateral AV connection. The laser lesion was confined largely to the atrial aspect of the AV annulus. We conclude that laser catheter ablation of accessory pathways is feasible in humans.

Ventricular tachycardias of right ventricular origin: markers of subclinical right ventricular disease

The diagnosis of subclinical myocardial disease in patients with ventricular tachycardias of right ventricular (RV) origin and no overt cardiac abnormalities is important, inasmuch as the presence of RV cardiomyopathy or arrhythmogenic dysplasia can be associated with a poor prognosis. To this end the relative value of symptoms, ECG features of ventricular tachycardia, signal-averaged ECGs, and RV echocardiograms as compared with endomyocardial biopsy findings was prospectively evaluated. Twenty-seven patients with chronic ventricular tachycardias with a left bundle branch block-like morphology, presumed to be of RV origin, were studied. Clinical examination findings, 12-lead ECGs in sinus rhythm, radiographs of the chest, coronary angiograms, and left ventricular cineangiograms were normal in all patients. RV biopsies were abnormal in 11 patients (41%) with findings suggestive of RV dysplasia or cardiomyopathy. A multivariate analysis showed a significant correlation between an abnormal biopsy and sustained ventricular tachycardia (p < 0.05), tachycardia with a superior frontal plane axis (p < 0.001), an abnormal signal-averaged ECG (p < 0.05), and an abnormal RV echocardiogram (p < 0.001). An abnormal RV echocardiogram was both a sensitive (73%) and a specific (94%) indicator of an abnormal RV biopsy. Sustained tachycardia although sensitive (90%) had a low specificity (56%). In comparison, a superior frontal plane axis of ventricular tachycardia and an abnormal signal-averaged ECG were indicative of high specificity and low sensitivity for abnormal myocardial histologic findings.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum lipase levels in nonpancreatic abdominal pain versus acute pancreatitis

OBJECTIVE

1) To determine whether serum lipase is elevated in patients with nonpancreatic abdominal pain, and 2) to compare the levels of serum lipase and serum amylase found in patients with nonpancreatic abdominal pain with those found in acute pancreatitis in order to differentiate between the two groups.

METHODS

Serum lipase and amylase levels were estimated in 95 patients with nonpancreatic abdominal pain (group A). These levels were then compared with those found in 75 patients with acute pancreatitis (group P).

RESULTS

Serum amylase in group A ranged from 11 to 416 U/L [mean 58 +/- 46 (SD)]. Three patients (3.3%) had raised amylase levels. The maximum elevation noted in this group was 416 U/L. Serum amylase in group P ranged from 124 to 13,000 U/L (mean 1620 +/- 1976). Twenty of the 75 patients (27%) in group P had levels that overlapped those found in group A. The serum lipase in group A ranged from 3 to 680 U/L (mean 111 +/- 101). Ten of the 93 patients (11%) had elevated lipase levels. The maximum elevation noted was roughly 3 times normal (680 U/L). Serum lipase in group P ranged from 711 to 31,153 (mean 6705 +/- 7022). None of the patients in group P had levels that overlapped those found in group A. The sensitivity of a serum lipase level > 3 normal in detecting acute pancreatitis was 100% and the specificity was 99%. The corresponding figures for serum amylase were 72% and 99%, respectively.

CONCLUSION

A serum lipase level > 3 normal has a better diagnostic accuracy than serum amylase in differentiating nonpancreatic abdominal pain from acute pancreatitis.

Metoclopramide decreases thiopental hypnotic requirements

We compared the effect of metoclopramide (MCA) with droperidol (DPD) on thiopental hypnotic requirements in 96 unpremedicated female patients. The study was randomized, double-blind, and placebo-controlled. The response to the verbal command was used as an end-point of anesthesia. Two methods of determination of thiopental hypnotic requirements were used: titration (infusion of thiopental at a rate of 0.5 mg.kg-1 x min-1) until the end-point was reached and construction of the dose-response curve based on bolus injections of predetermined doses of thiopental (with the use of probit analysis). The ED50 value of thiopental determined by probit analysis was reduced after the 0.2 mg/kg MCA administration by 44% (P < 0.0001). The thiopental hypnotic requirements obtained with the titration method were as follows: 5.3 +/- 0.3 mg/kg in control, 4.5 +/- 0.2 mg/kg (delta 14%, P < 0.03) with 0.1 mg/kg MCA, 3.2 +/- 0.2 mg/kg (delta 39%, P < 0.0001) with 0.2 mg/kg MCA, and 2.9 +/- 0.2 mg/kg (delta 45%, P < 0.0001) with 0.4 mg/kg MCA. DPD decreased thiopental hypnotic requirements almost to the same degree as MCA, with the ceiling effect observed at doses of 0.01 and 0.02 mg/kg (delta 44%, P < 0.0001). The results indicate that MCA causes a profound decrease in thiopental hypnotic requirements. The similarity between the thiopental sparing effects of MCA and DPD suggests that the blockade of D2 receptors is the main mechanism underlying this effect.

Total pectoral implantation: a new technique for implantation of transvenous defibrillator lead systems and implantable cardioverter defibrillator

We describe a new approach to total pectoral implantation of cardioverter defibrillators with an endocardial defibrillation lead system. Endocardial lead configuration used was an FDA approved right atrial-superior vena cava defibrillation spring electrode, right ventricular bipolar sensing electrode, and a pectoral patch. Endocardial leads were implanted via a cephalic or an axillary venesection. Pectoral patch was placed in a submuscular position. In case of failure to obtain satisfactory thresholds, a small intercostal thoracotomy was performed via the same skin incision and patch placed over the epicardium instead of submuscular position and used with the right atrial spring electrode. The device was implanted in the pectoral region, submuscularly, over the patch. Sixteen consecutive patients underwent this approach. With a submuscular patch, adequate defibrillation thresholds (< or = 15 joules [J]) were obtained in 14 (87.5%) patients. In the other two, defibrillation thresholds of < or = 15 J were obtained with a epicardial patch. Pectoral implantation of the device was feasible in all 16 patients and none needed repositioning. Average postimplant hospital stay was 5 days. During follow-up period (average 5 months), none of the patients reported any major local symptoms and no problems have been encountered in device interrogation. Thus, total pectoral implantation of the cardioverter defibrillator including the patch, leads, and the device is feasible. Furthermore, in case of failure to obtain adequate defibrillation thresholds with submuscular patch, an epicardial patch can easily be implanted and allows 100% successful defibrillation at energy levels of < or = 15 J with right atrial patch configuration.

Probable de novo 17q duplication (q11.2-->q21.1): a newly recognised chromosomal syndrome in a child with Klinefelter's syndrome

A child is described with a previously unreported probable trisomy for a segment of the long arm of chromosome 17 responsible for some distinct clinical features. These include craniofacial and skin abnormalities, failure to thrive, partial malrotation of the gut, malabsorption, gastro-oesophageal reflux, neurodevelopmental delay, autonomic disturbance, and cardiac and CNS abnormalities. The coexistence of Klinefelter's syndrome (47,XXY) is of minor significance in relation to this child's phenotype.

The reduced canine pancreas to study the effects of intra-operative radiotherapy

A canine model is described to study the tolerance of the pancreas to intra-operative radiotherapy (IORT). The canine pancreas is a horseshoe-shaped organ. To create a homogeneous delivery of IORT to the whole pancreas surgical manipulation is necessary which may induce pancreatitis. A resection of the left and right lobes of the pancreas facilitates the delivery of IORT, reduces the risk of pancreatitis and will demonstrate, eventually, minimal functional changes in the exocrine and endocrine pancreas at an earlier stage. Sixteen beagles were used. Investigations before and after the reduction procedure were intravenous glucose tolerance tests, serum insulin levels, faecal fat excretion, blood chemistry tests and body weight. Eight weeks after the pancreas reduction 15 dogs underwent an IORT procedure in which 25, 30 or 35 Gy IORT was delivered to the pancreatic remnant. We conclude that the pancreas reduction technique used to study the effects of IORT to the canine pancreas is feasible without mortality or morbidity. Endocrine and exocrine pancreatic function remained normal with a minimal follow-up of 3 months.

Device use patterns and clinical outcome of implantable cardioverter defibrillator patients with moderate and severe impairment of left ventricular function

The beneficial effects of implanted cardioverter defibrillator (ICD) therapy in patients with malignant ventricular tachyarrhythmias and variable degrees of left ventricular (LV) dysfunction are debated. ICD use and patient survival were examined in 128 patients with malignant ventricular arrhythmias and moderate or severe LV dysfunction. Group I included 64 patients with moderate LV dysfunction (LV ejection fraction of > 30%) and group II, 64 patients with severe LV dysfunction (LV ejection fraction of < or = 30%). Follow-up period ranged from 1 to 78 months. The two groups were similar in age, incidence of coronary artery disease and presenting arrhythmia. The mean LV ejection fraction in group I was 44% +/- 8% and group II was 22% +/- 5% (P < 0.0001). At 4 years of follow-up, 66% of patients from group I and 62% from group II (P = NS) had ICD activation for presumed ventricular tachyarrhythmia. Survival was calculated using actuarial analysis. Arrhythmic or sudden death mortality at 4 years of follow-up was 4% in group I and 7% in group II (P = NS). Cardiac mortality was for group I, 7% (P < 0.05), 12% (P < 0.01), 15% (P < 0.01), and 15% (P < 0.01) for follow-up years 1, 2, 3, and 4, respectively. For group II, cardiac mortality was 27%, 36%, 41%, and 41% for follow-up years for 1, 2, 3, and 4, respectively. The majority of cardiac deaths in both groups was observed in the first 2 years of follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Survival of implantable cardioverter-defibrillator recipients: role of left ventricular function and its relationship to device use

The quantitative benefit of ICD therapy in patients with malignant ventricular tachyarrhythmia with different degrees of left ventricular dysfunction is unclear. We evaluated patterns of ICD use and survival in 112 patients with moderate to severe left ventricular dysfunction. Group 1 included 57 patients with moderate left ventricular dysfunction (defined as left ventricular ejection fraction greater than 30%) and group 2 comprised 55 patients with severe left ventricular dysfunction (defined as ejection fraction equal to or less than 30%). The follow-up period ranged from 1 to 78 months. Age, incidence of coronary artery disease, and presenting arrhythmia in the two groups were similar. The mean left ventricular ejection fraction in group 1 was 44.6 +/- 8.2% and in group 2 was 21.6 +/- 6% (p < 0.0001). At 3 years of follow-up 65% of the patients in group 1 and 71% in group 2 (p = NS) had ICD activation for presumed ventricular tachycardia. Survival was calculated by means of actuarial analysis. Arrhythmia or sudden death mortality at 4 years of follow-up was 5% in group 1 and 9% in group 2 (NS). Cardiac mortality was higher in patients with severe left ventricular dysfunction reaching levels of statistical significance at 2 years of follow-up. At 2 years of follow-up it was 12% in group 1 and 40% in group 2 (p = 0.05), and at 4 years of follow-up it was 15% in group 1 and 43% in group 2 (p < 0.01). In both groups there was no difference in cardiac mortality in patients who did and did not have appropriate ICD shocks.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy of flecainide, sotalol, and verapamil in the treatment of right ventricular tachycardia in patients without overt cardiac abnormality

OBJECTIVE

A comparison of the efficacy of verapamil, sotalol, and flecainide to suppress right ventricular tachycardia (VT) in patients with a clinically normal heart.

DESIGN

Patients underwent treatment serially with verapamil (360 mg daily), sotalol (240 or 320 mg daily), and flecainide (200 or 300 mg daily), (the larger dose was for patients heavier than 80 kg) to suppress tachycardia. Each drug was given orally for five half lives before testing.

PATIENTS

23 patients with right VT associated with a clinically normal heart were studied.

OUTCOME MEASURES

The effects of drug treatment were examined by the number of ventricular events on 24 hour Holter monitoring, and the ability of tachycardia to be induced by treadmill exercise testing (Bruce protocol) and programmed ventricular stimulation (Wellens protocol), compared with drug free baseline tests.

SETTING

Patients were studied in a tertiary referral centre.

RESULTS

All three drugs suppressed ventricular salvos (> 3, < 5 consecutive ventricular premature contractions) (p < 0.01) and VT (p < 0.05) on Holter monitoring and did not differ statistically in effect. Exercise induced VT was also suppressed by all three drugs (p < 0.01), and of these sotalol was the most effective although this was not statistically significant (14/23 inducible when drug free, 4/23 on flecainide, 2/23 on sotalol, 5/23 on verapamil). Sustained and non-sustained VT induced by programmed stimulation was also suppressed by the three drugs (p < 0.01) and again sotalol was the best of these though the differences did not achieve statistical significance (17/23 inducible when drug free, 4/17 on flecainide, 2/17 on sotalol, and 6/17 on verapamil). Proarrhythmic effects of drugs were found in a few patients. There was no difference in the efficacy of the drugs in patients with histological abnormalities of the myocardium when compared with those of normal histology.

CONCLUSIONS

Ventricular tachycardia associated with a clinically normal heart can be suppressed by flecainide, sotalol, or verapamil. In individual patients sotalol was the most frequently effective drug (effective in > 89% of patients) and is a suitable choice for first line treatment.

Comparison of clinical benefits and outcome in patients with programmable and nonprogrammable implantable cardioverter defibrillators

Technological advances in implantable cardioverter defibrillators (ICDs) have provided a variety of programmable parameters and antitachycardia therapies whose utility and impact on clinical outcome is presently unknown. ICDs have capabilities for cardioversion defibrillation alone (first generation ICDs), or in conjunction with demand ventricular pacing (second generation ICDs), or with demand pacing and antitachycardia pacing (third generation ICDs). We examined the pattern of antitachycardia therapy use and long-term survival in 110 patients with sustained ventricular tachycardia (VT) or ventricular fibrillation (VF). Group I included 62 patients with nonprogrammable first generation ICDs that delivered committed shock therapy after ventricular tachyarrhythmia detection based on electrogram rate and/or morphology was satisfied. Group II included 48 patients with multiprogrammable ICDs (including second and third generation ICDs) that had programmable tachyarrhythmia detection based on rate and tachycardia confirmation prior to delivery of electrical treatment with either programmable shocks and/or, as in the third generation ICDs, antitachycardia pacing. Incidence and patterns of antitachycardia therapy use and long-term survival were compared in the two groups. The incidence of appropriate shocks in patients who completed 1 year of follow-up was significantly greater in group I (30 of 43 patients = 70% vs 11 of 26 patients = 42%; P less than 0.05). In the total follow-up period, a significantly larger proportion of group I patients as compared to group II patients used the shock therapies (46 of 62 patients = 74% vs 25 of 48 patients = 52%; P less than 0.01), with the majority doing so within the first year of implantation (96% and 92%, respectively). Although the frequency of antitachycardia therapy activation was similar, the number of shocks delivered per patient was lower in group II, particularly in the initial 3 months of follow-up (P = 0.06). No clinical variable aided in identifying users from nonusers of antitachycardia therapy. Arrhythmic mortality was virtually eliminated in both groups. Two-year actuarial cardiac survival in the two groups was similar (group I = 78% vs group II = 84%; P greater than 0.2). Survival from cardiac mortality in users and nonusers of antitachycardia therapies was also similar in both groups (P greater than 0.2) and in the total patient group (P greater than 0.2). We conclude that programmable ICDs continue to confer advantages in prevention of sudden death that were observed with nonprogrammable ICDs and can be expected to improve patient tolerance and physician acceptance of device therapy for VT/VF.

Prospective comparison of biphasic and monophasic shocks for implantable cardioverter-defibrillators using endocardial leads

Bidirectional shocks using 2 current pathways have been used in endocardial lead systems for implantable cardioverter-defibrillators, but the optimal shock waveform for endocardial defibrillation is unknown. The clinical efficacy and electrical characteristics of bidirectional monophasic and biphasic shocks for endocardial cardioversion-defibrillation of fast monomorphic or polymorphic ventricular tachycardia (VT), or ventricular fibrillation (VF) were evaluated. Thirty-three patients (mean age 60 +/- 12 years, and mean left ventricular ejection fraction 34 +/- 13%) were studied. Defibrillation catheter electrodes were located in the right ventricular apex and superior vena cava/right atrial junction. A triple-electrode configuration including the 2 catheter electrodes and a left thoracic patch was used to deliver bidirectional shocks from the right ventricular cathode to an atrial anode (pathway 1) and the thoracic patch (pathway 2). The shock waveforms examined were sequential and simultaneous monophasic, and simultaneous biphasic. The efficacy of 580 V (20 J) shocks for fast monomorphic VT were comparable for the 3 waveforms (73% for sequential monophasic, 73% for simultaneous monophasic, and 100% for simultaneous biphasic). However, for polymorphic VT and VF, 580 V sequential monophasic shocks had a significantly lower efficacy (25%) than did simultaneous monophasic (75%; p = 0.01) or biphasic (89%; p less than 0.001) shocks. Single-shock defibrillation thresholds with simultaneous biphasic shocks were significantly lower (9 +/- 5 J) than were those with simultaneous monophasic shocks (15 +/- 4 J; p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Streptococcus associated toxic shock

In the past few years, there appears to have been a change in the spectrum of disease caused by group A beta-haemolytic streptococcus (GABHS), and a toxic shock-like syndrome caused by this organism has recently been described in adults. We report four children with an acute illness characterised by rapid progression of shock, erythematous rash, multisystem organ involvement, electrolyte derangements, and desquamation who fulfil the previously established diagnostic criteria for toxic shock syndrome. Three of the children had extensive cutaneous and soft tissue infection and the fourth had peritonitis. All four developed bacteraemia. Treatment included aggressive cardiovascular resuscitation and antibiotic therapy. Although no patient died, they suffered multiple and severe complications requiring prolonged treatment and hospitalisation. Streptococcal toxic shock syndrome is a separate and clearly defined entity occurring in previously healthy children.

Effect of automobile exhaust on the distribution of trace elements and its modulation following Fe, Cu, and Zn supplementation

The effect of automobile exhaust on the distribution of trace elements with special reference to Pb and its modulation following Cu, Zn, and Fe supplementation, in mouse organs, has been studied using Energy Dispersive X-ray Fluorescence technique. Seven elements, namely K, Fe, Cu, Zn, Br, Rb, and Pb, were detected in all the organs. The maximum concentration of Pb was found in lungs followed by that in liver and kidney. The effect of automobile exhaust was found to be significant on the concentrations of Fe and Pb; their concentrations were found to increase in all the organs. However, the concentrations of Cu and Zn were found to be decreased significantly in the liver. In the animals given Fe, Cu, or Zn supplementation along with motor exhaust, the percentage change in the concentration of Pb in lungs was decreased, and that of Fe was increased significantly. In kidney, no significant change was observed for the animals given Cu and Zn, whereas for animals given Fe, the level of Pb decreased significantly. In liver, the reduction in the level of Zn in the exhaust-exposed animals was made up and the level of Pb was reduced following Zn supplementation. These results clearly indicate that Fe and Zn play an important role in Pb metabolism and tend to lower the absorption of Pb. The effect of Fe is more pronounced than that of Zn, whereas the effect of Cu seems to be insignificant.

Effect of alfentanil on hypnotic and antinociceptive components of thiopental sodium anesthesia

STUDY OBJECTIVE

To determine the effects of alfentanil on the hypnotic and antinociceptive components of thiopental sodium anesthesia.

DESIGN

Randomized double-blind study.

SETTING

Inpatients at a university-affiliated county hospital.

PATIENTS

Eighty unpremedicated ASA physical status I or II female patients aged 18 to 60 years, with a weight range of 50 to 90 kg.

INTERVENTIONS

Intravenous injection of thiopental sodium in doses ranging from 1.0 mg/kg to 6.0 mg/kg with or without the addition of alfentanil, 0.01 mg/kg.

MEASUREMENTS AND MAIN RESULTS

Dose-response curves were determined for the following three endpoints of anesthesia: eye opening in the response to voice command; eye opening in the response to noxious stimulation induced by pressure on the trapezius muscle; and purposeful movement in the response to the same type of noxious stimulation. The addition of alfentanil, 0.01 mg/kg, markedly decreased thiopental ED50 values for all three endpoints: from 2.6 mg/kg to 1.9 mg/kg (p less than 0.02) for eye opening to voice command, from 3.2 mg/kg to 1.9 mg/kg (p less than 0.0005) for eye opening to noxious pressure, and from 4.2 mg/kg to 2.4 mg/kg (p less than 0.0001) for purposeful movement to noxious pressure. The alfentanil-induced increase in thiopental potency for the antinociceptive effect was greater than that for the hypnotic effect (75% vs 36%, p = 0.02).

CONCLUSIONS

Alfentanil strengthened both the hypnotic and antinociceptive components of thiopental anesthesia, although to a different degree: the antinociceptive component more so than the hypnotic, possibly because each component of anesthesia has different underlying mechanisms.

Signal averaging of the electrocardiogram in the remote differential diagnosis of broad complex tachycardias

The diagnosis of the origin of a broad complex tachycardia may be difficult, especially in the absence of a 12-lead electrocardiogram of the tachycardia. This study investigates the value of signal averaging in the differential diagnosis of broad complex tachycardia. Signal averaging during sinus rhythm was performed in 102 consecutive patients who presented with broad complex tachycardia (QRS width greater than 110 ms), in whom a definitive electrophysiological diagnosis was made. The presence of late potentials was determined on the basis of two definitions, the second including total QRS duration. The patients studied included 75 with ventricular tachycardia; 33 of these patients had suffered previous myocardial infarction, five had dilated cardiomyopathy, and 37 had a 'normal' heart. Of the 27 patients with supraventricular tachycardia, 22 had an atrioventricular accessory pathway (seven with a delta wave in sinus rhythm), three had atrioventricular nodal tachycardia and two had atrial tachycardia. The sensitivity of late potentials for the diagnosis of ventricular tachycardia was low utilizing both definitions (28% and 45%) although specificity was high (96% and 95%). The sensitivity for the diagnosis of ventricular tachycardia was higher for patients with ischaemic heart disease (43% and 70%) but very low for patients with ventricular tachycardia and a normal heart (16% and 22%). In conclusion, signal averaging in the remote diagnosis of broad complex tachycardia is specific but not sensitive for ventricular tachycardia, which limits its usefulness in selecting patients for electrophysiological study.

Experience with a third-generation implantable cardioverter-defibrillator

A Medtronic 7216A pacemaker cardioverter-defibrillator was implanted in 16 patients (mean age 56 years) with sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) and organic heart disease with a mean left ventricular ejection fraction of 33%. Endocardial and epicardial defibrillation shock efficacy was evaluated before or at implant using 1 to 3 shock patterns, i.e., monophasic single, sequential or simultaneous shocks with dual and triple electrode configurations. Endocardial leads used a common right ventricular cathode and dual anodes, whereas epicardial leads used 2 or 3 helical coil patches. VT termination was evaluated using pacing or shock therapy, or both, whereas only shocks were used in VF. Programmable bradycardia pacing, individual zones for VT and VF detection and individualized pacing and shock therapy for VT and VF were used. Monophasic shocks had epicardial defibrillation thresholds ranging from 3 to 18 (mean 10) J and were comparable for sequential and simultaneous shocks (p greater than 0.2). VT detection rates ranged from 340 to 470 ms and VF detection rates from 270 to 330 ms. VT or VF induction, or both, was performed noninvasively in 13 patients after implant and was reproducibly terminated by rapid pacing alone (5 patients), low-energy shocks (2 patients), high-energy shocks (3 patients) and combined therapy (3 patients). Intermediate or high-energy shocks terminated all induced VF episodes. During follow-up (2 to 12 months), there have been 2 noncardiac deaths. Electrical therapy was delivered in 7 patients, for VT (3 patients), VT and VF (3 patients) and indeterminate tachyarrhythmia (1 patient). All VT/VF episodes were successfully terminated, with 78 of 96 (81%) spontaneous VT episodes terminated by pacing. Follow-up reprogramming was required in 5 patients. It is concluded that successful application of individualized electrical therapy prescriptions in patients with VT/VF is feasible. Pacing therapies, which are effective for induced VT, can be reliably used for effective long-term spontaneous VT termination in conjunction with shock therapy and can permit reduced patient exposure to shock therapy. Thus, a programmable hybrid pacemaker cardioverter-defibrillator system provides nonthoracotomy implantation, effective VT/VF termination, demand ventricular pacing and noninvasive modes for arrhythmia induction, event monitoring and clinical trouble-shooting.

Density-dependent regulation of epidermal growth factor receptor expression

Previous studies have demonstrated that binding of peptide growth factors such as epidermal growth factor (EGF) decreases as cell density increases. We now report that binding of EGF to MDA 468 breast carcinoma cells is reduced as cells increase in density with time in culture. Cells at low density bound more EGF per cell than cells at higher density. The reduction of EGF binding was due to a reduction in receptor number. Metabolic labeling of MDA 468 cells with [35S]-methionine followed by immunoprecipitation of the EGF receptor (EGFR) indicated that the amount of total receptor protein was decreased. Using RNA blot hybridization, we found that high-density cells contained decreased amounts of EGFR transcripts. Northern analysis revealed that both the 10- and 5.6-kilobase mRNA transcripts encoding the EGFR were decreased. These data suggest that increasing cell density with time in culture results in modulation of EGFR content, with changes at the level of both protein and mRNA expression.

Modulation of epidermal growth factor receptors by gamma interferon in a breast cancer cell line

Interferons (IFNs) may inhibit cell growth via their interaction with growth factors and their receptors. We examined the ability of IFN to modulate Epidermal Growth Factor (EGF) receptor binding in a human breast carcinoma cell line, MDA 468. Gamma interferon and alpha interferon inhibited growth of MDA 468 cells in a dose and time-dependent manner. IFN-gamma and Epidermal Growth Factor (EGF), a known inhibitor of MDA 468 growth, inhibited growth in an additive fashion. Growth inhibition by gamma but not alpha interferon was associated with a decrease in the number of EGF receptors (EGFRs) after 5 days. Scatchard analysis of receptor binding data revealed that gamma but not alpha interferon reduced the number of available EGF receptor binding sites without any change in the affinity of the receptor. IFN significantly affected EGF receptor expression, and the decrease in receptor expression was associated with growth inhibition.

Prospective evaluation of a protocol for induction of sustained ventricular tachycardia in patients referred to a tertiary centre

All eight stages of a stimulation protocol that used one then two extrastimuli from the right ventricular apex in sinus rhythm and three ventricular drive rates (100, 120, and 140 beats/min) were performed in 24 patients with recurrent spontaneous sustained ventricular tachycardia despite drug treatment. Twenty two of the patients had sustained a previous myocardial infarct and 18 were on long term treatment with amiodarone. Sustained (greater than 30 s) ventricular tachycardia was induced in all patients. Two extrastimuli were significantly more likely to induce sustained ventricular tachycardia than one extrastimulus, both overall and individually for the three ventricular drive rates. A ventricular drive rate of 140 beats/min was significantly more likely to induce ventricular tachycardia than ventricular drive rates of 100 and 120 beats/min which were significantly more effective than sinus rhythm. A ventricular drive rate of 140 beats/min with one or two extrastimuli induced ventricular tachycardia in 23/24 (95%) of the patients in this study. The full eight stage protocol was progressive separately for both extrastimuli and ventricular drive rate but the last two stages (ventricular drive rate of 140 beats/min with one or two extrastimuli) were as effective as the entire protocol in inducing ventricular tachycardia.

Acute electrophysiologic effects of an HT2-serotonin antagonist, ketanserin, in humans

The acute electrophysiologic effects of an intravenous bolus of ketanserin, a 5HT2 serotonin blocker, were studied in ten patients (four females, six males) during invasive electrophysiology. Following baseline electrophysiologic measurements during sinus rhythm and fixed-rate atrial pacing at 600 ms, a bolus of 0.2 mg/kg ketanserin was given over a 3-minute period. After 30 minutes all measurements were repeated. Systemic blood pressure was measured at regular intervals throughout. During sinus rhythm, there was no significant change in the basic cycle length or in the PA, AH, HV, QRS, QT, and QTc intervals. During atrial pacing there was a nonsignificant increase in the QT interval, from 342 +/- 13 ms to 366 +/- 16 ms, and a significant increase in the QTc interval, from 422 +/- 27 ms to 449 +/- 29 ms (p less than 0.05). There was no reduction in blood pressure. Thus ketanserin produced a significant prolongation of the QTc interval, in the absence of hypokalemia, in humans.

Increased leukocyte phospholipase A2 activity and plasma lysophosphatidylcholine levels in asthma and rhinitis and their relationship to airway sensitivity to histamine

This study was carried out to determine leukocyte phospholipase A2 (PLA2) activity and plasma lysophosphatidylcholine (LPC) levels in normal subjects and in patients with asthma and rhinitis and to examine their relationship to airway sensitivity to histamine. Leukocyte PLA2 activity and plasma LPC levels were highly correlated (rs = 0.90), and were found significantly raised in both the disease groups, more so in the asthmatics. Both PLA2 activity and LPC levels showed overall negative correlations with the log dose of histamine producing a 35% fall in specific airway conductance (PD35 histamine) when the patients and the normal subjects were examined together (rs = -0.77 and rs = -0.83, respectively). The patients with leukocyte PLA2 activity more than 1.8 U (nmol 14C-AA released/mg protein/10 min at 30 degrees C) or plasma LPC levels more than 8.7% of total phospholipids (mostly asthmatics) showed high airway sensitivity to histamine (PD35 histamine less than or equal to 1 mg/ml). On the other hand, the PD35 histamine values of patients with leukocyte PLA2 activity equal to or less than 1.96 U or plasma LPC levels equal to or less than 8.7% overlapped with those of normal subjects in the range of 1.2 to 10 mg/ml. Lowering of plasma LPC levels, which probably reflect tracheobronchial LPC content as shown in guinea pigs, seems to be an essential step in the return of airway reactivity toward normal.

Ephedrine as a marker of intravascular injection in laboring parturients

Thirty healthy laboring parturients were randomly chosen to receive either normal saline (NS), ephedrine 10 mg (EPH-10), or ephedrine 15 mg (EPH-15) intravenously. Changes in maternal heart rate and blood pressure and fetal heart rate were monitored. A clinically useful and statistically significant (less than 0.001) increase in systolic blood pressure of 10 torr or more occurred in all 10 patients in the EPH-15 group. There was no adverse fetal outcome. Transient fetal tachycardia was seen in three fetuses in the EPH-15 group.

Respiratory responses to sustained isometric muscle contractions in man: the effect of muscle mass

1. Respiratory responses to sustained isometric contractions of a small mass of muscle (the finger flexors) during handgripping, and of a larger mass of muscle (the quadriceps) during extension of the leg at the knee, have been studied in man. 2. For both masses of muscle the increases of ventilation and of oxygen consumption were greater for contractions at 40% maximum voluntary contraction (MVC) than for contractions at 20% MVC. 3. The increase of ventilation was not related to the mass of muscle involved. 4. At 20% MVC oxygen consumption during contraction of the quadriceps was greater than that during handgripping. At 40% MVC the oxygen consumptions were similar. The oxygen debts following both handgrip and knee extensor contractions at 20% MVC were negligible. Following 40% MVC contractions of the quadriceps a significant oxygen debt was recorded but no debt was apparent following 40% MVC contractions of the finger flexors. 5. The increases of ventilation during isometric exercise were generally inappropriately high for the increases of gas exchange. This led to reductions of the end-tidal carbon dioxide pressure (PET,CO2), especially towards the end of exercise. 6. Following 40% MVC handgripping hyperventilation continued despite the reduced alveolar PCO2. By contrast, following 40% MVC knee extension PET,CO2 transiently rose above the resting level, but did not stimulate ventilation. 7. It appears that following fatiguing isometric contractions hyperventilation continues and appears to be independent of alveolar PCO2. It is suggested that stimuli which increase ventilation during exercise may continue to act during the early phase of recovery.

Significance of signal-averaged electrocardiography in relation to endomyocardial biopsy and ventricular stimulation studies in patients with ventricular tachycardia without clinically apparent heart disease

Signal-averaged electrocardiography (ECG) was performed in 38 patients (mean age 38 years, range 15 to 70) with ventricular tachycardia who had no clinical evidence of structural heart disease. Spontaneous ventricular tachycardia was nonsustained in 23 patients and sustained in 15. None of the patients had symptoms of heart failure or ischemic heart disease, and at cardiac catheterization none had significant coronary artery disease or left ventricular wall motion abnormalities. In addition, all patients underwent left and right ventricular endomyocardial biopsy and ventricular stimulation studies. Signal-averaged ECG was performed and late QRS potentials were defined with use of Simson's method. Late QRS potentials were detected in a minority (18%) of patients including 2 of 23 with nonsustained and 5 of 15 with sustained (p = NS) ventricular tachycardia. Fifteen patients (40%) had abnormal endomyocardial biopsy results and these findings were more common in patients with sustained than in those with nonsustained ventricular tachycardia (9 of 15 versus 6 of 23, p less than 0.05). Late potentials were associated with abnormal endomyocardial biopsy findings (6 of 15 versus 1 of 23, p less than 0.01). An increase in fibrous tissue was the most frequent histopathologic abnormality; this increase was quantified by morphometric methods and compared with biopsy findings in normal control subjects. In the control group the proportion of collagen in relation to myocytes was less than 10%. All patients with both late potentials and abnormal biopsy findings had a greater than 15% ratio of collagen to myocytes in at least one specimen and the biopsies revealed marked interstitial fibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Signal-averaged electrocardiography and the significance of late potentials in patients with "idiopathic" ventricular tachycardia: a review

High-frequency, low-amplitude electrical activity during and in continuation with the ventricular electrogram in sinus rhythm is now accepted as an indirect marker for reentrant pathways in ventricular muscle. Because the amplitude of these signals is low, much effort has recently been directed toward finding methods of recording these noninvasively. This essentially involves averaging the electrocardiogram, amplifying it, and filtering out the low frequency and nonrepetitive signals. This review discusses the methods presently available for signal-averaged electrocardiography and their background. The clinical application of signal-averaged electrocardiograms in patients with or suspected to have ventricular tachycardia is summarized. Data regarding the incidence of abnormal signal-averaged electrocardiography in patients with "idiopathic" ventricular tachycardia compared with normal subjects and patients with ventricular tachycardia related to ischemic heart disease are presented.

Echocardiographic and histologic evaluation of the right ventricle in ventricular tachycardias of left bundle branch block morphology without overt cardiac abnormality

The right ventricle was investigated by multiple biopsies and detailed echocardiographic evaluation, including measurement of cavity dimensions at the level of the inflow, body and outflow tract, in 27 patients with right ventricular tachycardia who had no clinical evidence of an underlying morphologic abnormality. Nine (33%) patients had abnormal biopsy results, with a quantifiable increase in interstitial fibrosis. Abnormal echocardiograms, defined as an increase in greater than or equal to 2 dimensions of the right ventricular cavity or wall motion abnormalities or both, were seen in 9 patients. There was a strong association between abnormal myocardial histologies and abnormal right ventricular echocardiograms (p less than 0.001). An abnormal echocardiogram was 94% specific and 80% sensitive for an abnormal biopsy. The findings of echocardiography and biopsy were correlated with the electrocardiographic features of the tachycardia. Evidence of right ventricular disease was seen in all 6 patients with superior frontal plane axis of clinical tachycardia as compared with 4 of 21 with inferior axis (p less than 0.001). Thus, 2-dimensional echocardiography is a sensitive means of diagnosing right ventricular disease in patients with nonischemic tachycardias of left bundle branch block morphology. A superior frontal plane axis of ventricular tachycardia in this group strongly suggests right ventricular disease, whereas an inferior frontal plane axis is frequently not associated with any morphologic or histologic abnormality of the right ventricle.

Megaprostheses in the treatment of primary malignant and metastatic tumors in the hip region

Twenty patients with malignant bone tumors of the hip region were treated surgically by resection and reconstruction with an endoprosthesis. Histologic types included five primary bone tumors and 15 metastatic lesions. At review four primary bone tumor patients are still alive without evidence of disease. The length of the observation period varied from 26 to 104 months. Eleven patients with metastatic bone disease died. The average postsurgical survival time was 23 months. All patients were able to walk with or without a cane. Failure of an endoprosthesis occurred in one case. According to the Enneking Evaluation System 11 patients had a good and 9 a fair result.

Optimal atrioventricular delay at rest and during exercise in patients with dual chamber pacemakers: a non-invasive assessment by continuous wave Doppler

The optimal atrioventricular delay at rest and during exercise was investigated in nine patients with heart block and implanted dual chamber pacemakers. All patients studied had normal left ventricular function and a normal sinus node rate response to exercise. Cardiac output was measured by continuous wave Doppler and was calculated as the product of stroke distance measured by Doppler at the left ventricular outflow, aortic root area measured by M mode echocardiography, and heart rate. Pacemakers were programmed in the DDD mode. Cardiac output was measured with the patient at rest while supine and while erect and at the peak of submaximal exercise (the end of stage 1 of the Bruce protocol) with the pacemakers programmed to the following atrioventricular intervals: 75-80 ms, 100-110 ms, 140-150 ms, and 200 ms. During exercise the basic pacing rate was programmed to 70 beats/min. Cardiac output at rest while supine and erect was greatest with an atrioventricular delay of 140-150 ms and it was significantly higher than that with an atrioventricular delay of 75-80 ms. On average there was a 31% decrease in cardiac output when patients stood up. During treadmill exercise, however, cardiac output was greatest when the atrioventricular delay was 75-80 ms, and this was significantly higher than the cardiac output with atrioventricular delays of 150 and 200 ms. During exercise 1:1 atrioventricular relations were maintained in patients at all atrioventricular intervals. In patients with atrioventricular sequential pacemakers cardiac output at rest is greatest with an atrioventricular delay of 140-150 ms but during exercise the optimal atrioventricular delay is shorter. Rate modulation of the atrioventricular interval may improve the haemodynamic response and possibly exercise tolerance in patients with dual chamber pacemakers.

Comparative evaluation of chronotropic responses of QT sensing and activity sensing rate responsive pacemakers

The rate responses of activity sensing (ATS) and QT sensing (QTS) rate responsive pacemakers to different forms and durations of exercises were compared. Nine patients with ATS and five with QTS were studied. All had complete heart block and atrial arrhythmias. At the onset, the pacemakers were programmed to achieve a pacing rate of 100-110 bpm by the end of stage 1 of the Bruce protocol, and to a pacing rate range of 70-150 bpm. With progressive exercise, using a treadmill (Bruce protocol), the maximum pacing rates in the two groups were not significantly different (mean +/- SD: 123 +/- 18 vs 129 +/- 23 bpm, ATS vs QTS). The time taken to return to the baseline pacing rate during recovery was significantly longer with QTS (178 +/- 70 vs 264 +/- 68 s, p less than 0.05). Brief exercise tests on a treadmill were performed for 3 min each with different combinations of treadmill speeds (1.2 and 2.5 mph) and gradients (0, 5, 10 and 15%). In both groups of patients, faster walking speed was associated with a faster pacing rate at each gradient. However, with increasing gradients, at each speed, there was a rise in the maximum pacing rate only in patients with QTS. During brief exercise tests, the maximum rate was achieved by the end of exercise in patients with ATS, but was delayed by 33 +/- 20 s after exercise in patients with QTS.(ABSTRACT TRUNCATED AT 250 WORDS)

Recurrent paroxysmal complete heart block induced by vomiting

A woman had a 40-year history of vomiting associated with syncope. Spontaneous and induced vomiting was predictably associated with sinus bradycardia, paroxysmal atrioventricular block, and ventricular asystole. The clinical and laboratory studies carried out to illustrate the mechanism of this unusual complication of vomiting demonstrated it to be due to a vagovagal reflex initiated by distension of upper esophagus.

Mucoepidermoid carcinoma of the lung with intracranial metastases

Discussed is the first roentgenographic and post-mortem description of a patient with mucoepidermoid carcinoma of the lung who presented with intracranial metastases. The patient's primary tumor eluded physical diagnosis and bronchoscopic delineation. The autopsy confirmed minimal tumor involvement of the bronchial wall despite bulky regional and distant metastases.

Relative efficacy of various physical manoeuvres in the termination of junctional tachycardia

The ability of four vagotonic physical manoeuvres to terminate paroxysmal junctional tachycardias was tested in 35 patients with inducible and sustained arrhythmia. Each manoeuvre was used up to three times in an attempt to terminate an induced tachycardia and was judged to be effective if it terminated two out of the three induced episodes. The Valsalva manoeuvre in the supine position was effective in 19 (54%), right carotid sinus massage in 6 (17%), left carotid sinus massage in 2 (5%), and the diving reflex in 6 (17%) cases. 4 of the 6 patients who responded to right carotid sinus massage and all patients who responded to the diving reflex also responded to the Valsalva manoeuvre. The Valsalva manoeuvre while standing was effective in 9 (20%) patients only. Patients in whom the manoeuvres terminated the tachycardias were significantly younger than those who did not respond (median age: 30 vs 45 years, p less than 0.01). Physical manoeuvres were much more successful in terminating atrioventricular re-entry tachycardias (19/24) than atrioventricular nodal re-entry tachycardias (3/11, p less than 0.01). Efficacy of the manoeuvres was related to their bradycardic effect in sinus rhythm.