The natural history of Wolff-Parkinson-White syndrome in 228 military aviators: a long-term follow-up of 22 years

BACKGROUND

Wolff-Parkinson-White (WPW) syndrome poses a risk for tachyarrhythmias and sudden cardiac death. Most WPW studies have relatively limited numbers of subjects and brief follow-up periods.

METHODS

We reviewed records of 238 consecutive military aviators with WPW syndrome evaluated from 1955 to 1999. Follow-up was by questionnaires, telephone interviews, or death certificates. Events included sudden cardiac death and supraventricular tachycardia (SVT) (by electrocardiographic [ECG] documentation or suggestive symptoms).

RESULTS

The mean age was 34.3 years (range 17-56 years). Forty-two (42/238, 17.6%) had SVT (WPW syndrome) and 196 of 238 (82.4%) had the WPW ECG pattern only. The mean follow-up of 21.8 years (range 2-41 years) was obtained on 228 of 238 (96%) for a total of 4906 patient-years. Sudden cardiac death occurred in 1 of 228, an incidence of 0.0002 per patient-year (95% confidence interval 0.0-0.001). SVT occurred in 47 of 228 (20.6%) or 0.01 per patient-year. One hundred eighty-seven (187/228, 82%) initially had the WPW ECG pattern only; 28 of 187 (15.0%) reported SVT during follow-up. Forty-one (41/228, 18%) initially had WPW syndrome; 19 of 41(46.3%) reported additional SVT during follow-up.

CONCLUSION

Sudden cardiac death risk was low (0.02%/patient-year) in this WPW population. The SVT incidence was 1% per patient-year. Referral bias and some characteristics of the unique military aviator population may partly account for these low event rates. However, these results may be more applicable to unselected populations than are tertiary referral-based studies.

Parkinsonism: differential age-trend in Helicobacter pylori antibody

BACKGROUND

Parkinsonism is associated with prodromal peptic ulceration. Dopamine antagonists provoke experimental ulcer, dopaminergic agents protect, and might inhibit growth of Helicobacter pylori.

OBJECTIVE

To describe the relationship between H. pylori serology and parkinsonism.

METHODS

Serum H. pylori anti-urease-IgG antibody was measured in 105 people with (idiopathic) parkinsonism, 210 without, from same locality. None had received specific eradication therapy.

RESULTS

Controls showed a birth-cohort effect: antibody titre rose from 30 to 90 years (P < 0. 001). Parkinsonism obliterated this (disease status. age interaction, P < 0.05), the differential age trend not being attributable to social class. Those with diagnosed parkinsonism were more likely to be seropositive (odds ratio 2.04 (95% CI: 1.04, 4.22) P < 0.04) before 72.5 years. Overall, titre fell (P=0.01) by 5 (1, 9)% per unit increase in a global, 30-point rating (median 14 (interquartile range 10.5, 17)) of disease severity. No individual category of anti-parkinsonian medication (92% taking) had a differential lowering effect.

CONCLUSIONS

Higher prevalence of seropositivity in parkinsonism, before 8th decade, may be due to host susceptibility/reaction, or, conversely, infection with particular H. pylori strain(s) lowering dopaminergic status. Absence of a birth cohort effect in parkinsonism, despite similar social class representation, may be consequent on eradication, spontaneous (gastric atrophy) or by anti-parkinsonian medication.

Association of circulating TNF-alpha and IL-6 with ageing and parkinsonism

INTRODUCTION

We propose that the increase in TNF-alpha and IL-6 in the brain in idiopathic parkinsonism is in response to a peripheral immune/ inflammatory process, so ubiquitous as to be responsible for the resemblance between ageing and parkinsonism.

METHODS

Circulating cytokine was measured in 78 subjects with idiopathic parkinsonism and 140 without, aged 30 to 90 years, all obeying inclusion/exclusion criteria.

RESULTS

Serum TNF-alpha increased (P<0.0001) by 1.37 (95% CI 0.75, 2.00)% x y(-1), IL-6 by 2.63 (1.75, 3.52) (P<0.0005). TNF-alpha appeared elevated in parkinsonians whose postural and psychomotor responses were abnormal, being suppressed where they were normal: trends which contrasted with those in controls (P = 0.015 and 0.05, respectively). Parkinsonism appeared (P = 0.08) to have an effect on IL-6, equivalent to that of >10 years of ageing (28(-3, 69)%), but was not immediately related to between-subject differences in performance.

CONCLUSION

Ageing and pathogenetic insult may be confounded, age being a progression, not a risk, factor.

Parkinsonism: siblings share Helicobacter pylori seropositivity and facets of syndrome

OBJECTIVE

Given a history of peptic ulcer is more frequent in parkinsonism, to investigate the role of Helicobacter pylori in its pathogenesis and of cross-infection in familial aggregation.

METHODS

Facets of parkinsonism were quantified in 33 elderly subjects with idiopathic parkinsonism and in their 39 siblings with double the number of controls, all obeying inclusion/exclusion criteria. Specific-IgG antibody was assayed.

RESULTS

Siblings, compared with controls, had brady/hypokinesia of gait (P< or =0.002), bradykinesia of hands (P = 0.01), abnormal posture (P = 0.001), rigidity (P < 0.001) and seborrhoea/seborrhoeic dermatitis (P = 0.02). Both parkinsonians and siblings differed from controls in the odds of being H. pylori seropositive [odds ratios 3.04 (95% C.I.: 1.22, 7.63) and 2.94 (1.26, 6.86) respectively, P < 0.02], seropositivity being found in 0.70 of sufferers.

CONCLUSION

Familial transmission of chronic infection plus part of syndrome links Helicobacter with causality. Seropositivity not being universal throughout parkinsonism, consequent on gastric atrophy +/- sporadic antibiotic exposure, might explain less aggressive disease in older sufferers.

Cortisol is higher in parkinsonism and associated with gait deficit

INTRODUCTION

We propose an active pathogenic mechanism, involving circulating cortisol, in parkinsonism.

MATERIALS AND METHODS

Serum cortisol was measured in 96 subjects with idiopathic parkinsonism, 170 without, and in 17 spouses and 36 siblings of elderly sufferers with double the number of controls, all obeying inclusion/exclusion criteria.

RESULTS

Cortisol, adjusted for sampling time, was greater (17%, on average, P<0.001) in parkinsonians, but not in relatives. The central cortisol lowering effect of anti-muscarinics was seen (P=0.025). Selegiline may attenuate the disease, and parkinsonism is less frequent in tobacco smokers. Selegiline was associated with a lower cortisol (P=0.03): chronic smoking appeared (P=0.08) to be, irrespective of parkinsonism. Bowel stasis has been implicated in the pathogenesis: cortisol was higher in parkinsonians requiring laxatives (P=0.05). In controls, cortisol was lower, the longer the stride (P=0.02): in parkinsonians, this relationship was numerically reversed. A similar (P=0.01) group performance interaction was seen for deterioration, over 4 years, in gait.

CONCLUSION

Cortisol is doing harm or mirroring something which is. A common pathway for neuronal protection/rescue emerges.

Complications of warfarin therapy monitored by the International Normalized Ratio versus the prothrombin time ratio

The objective of our study was to determine the rates of bleeding complications and thromboembolic events in patients receiving oral anticoagulant therapy monitored with the prothrombin time (PT) ratio versus therapy monitored with the International Normalized Ratio (INR) using a retrospective time-series study design. Over 650 patients enrolled in a large anticoagulation clinic were studied during two time periods corresponding to the use of the PT ratio versus the INR to guide anticoagulant therapy, with over 400 patient-years of follow-up for each time period. The rate of bleeding complications using the PT ratio to guide therapy was 6.7% (1.2% major, 5.5% minor) per patient-year, compared with 2.9% (0% major, 2.9% minor) using the INR (p = 0.02). The rate of thromboembolic complications was 1.0% using the PT ratio, compared with 0.2% using the INR (p = NS). Therapy monitored with the INR required 19.8 visits per year, compared with 20.7 visits per year using the PT ratio. We conclude that the INR should be used to monitor oral anticoagulant therapy in an effort to reduce bleeding complications while maintaining an acceptable rate of thromboembolic events.

Anthropometric norms for the dialysis population

Although norms are available for healthy subjects, it is preferable, when interpreting anthropometry in individual dialysis patients, to compare measurements with norms for the stable dialysis population. The purpose of this study was to develop these reference anthropometric norms for dialysis patients. Triceps skinfold (TSF), subscapular skinfold (SSF), and mid-upper arm circumference (MUAC) measurements were made in 925 patients with no major illness, who were being treated by chronic maintenance dialysis in 27 dialysis facilities. Of these, 609 patients treated by hemodialysis (HD) were in subgroups large enough to compare with those from the National Health and Nutrition Examination Survey (NHANES) II. Diabetic patients were significantly different from nondiabetic patients; therefore, the two groups were analyzed separately. Male HD patients (diabetic and nondiabetic) did not differ significantly from the NHANES II data. Diabetic HD females did not differ significantly from the NHANES II data, except for the TSF of black women older than 55 years. Measurements of nondiabetic HD females (black and white) were significantly below the NHANES II data. In 138 continuous ambulatory peritoneal dialysis (CAPD) patients, measurements were similar to those of HD patients.

Normal extracellular calcium levels block kindled seizures

Seizures induced in animals by the kindling procedure have been described as an effective model of human epilepsy, principally because of the long lasting nature of this phenomenon (J. O. McNamara, 1984, Ann. Neurol. 16: 572-576). Permanent changes in the central nervous system associated with kindling should therefore provide insight onto of some forms of naturally occurring epilepsy. We report here the observation that in rats with fully developed kindled seizures, the exposure of the stimulation site to artificial cerebral spinal fluid (CSF) containing normal levels of calcium is able to block completely the seizure event. Exposure of the stimulation site to artificial CSF without calcium resulted in the return of the complete seizure. This implies that extracellular calcium levels are chronically reduced at the stimulation site of kindled rats and that this change in ion levels is necessary for the expression of the seizure.

The computer in quality control of hemodialysis patient care

A computerized, custom-designed medical information system (MIS) has been used for more than eight years in the care of patients with chronic renal failure treated by hemodialysis in a Cincinnati medical center. A comprehensive clinical data base that forms the core of the system readily serves the need for sophisticated quality control analysis. Application of the MIS in the day-to-day management of patients in one limited care dialysis clinic is detailed, with particular attention to its capacity to contribute to the quality of care of the individual patient. Data can be stored in the system periodically with relative ease; this enables physicians, nurses, and other personnel concerned with patient care to monitor the quality of procedures and treatments used in their patients. The system is shown to be cost-effective.

Effect of first and subsequent use of hemodialyzers on patient well-being. Analysis of the incidence of symptoms and events and description of a syndrome associated with new dialyzer use

To determine the effect of multiple dialyzer use on intradialytic symptoms, data from 26,592 successive dialyses on 147 patients were analyzed. Over the 26-month period of study 4,933 new dialyzers were used. All symptoms, considered together, occurred 1.3 times more frequently during the initial than during the subsequent use of the dialyzer. No symptom occurred more frequently in the second or subsequent use of the dialyzer. Concurrent chest and back pain were 41 times more frequent when the dialyzer was used for the first time. A syndrome associated with the first use of the dialyzer is described.

Lack of dihydrofolate reductase in human tumor and leukemia cells in vivo

Dihydrofolate reductase (DHFR), the main target for methotrexate and other antifolate compounds was found to be present in 100-200 times higher concentration in human cell lines grown in vitro than in human tumors or cells obtained in situ. The DHFR content of human cell lines in vitro however were equivalent to rodent tumor lines also measured in vitro. The enzyme was quantitated by [3H]methotrexate binding, [3H]dihydrofolate reduction to [3H]tetrahydrofolate, and immunoprecipitation with a monospecific anti-serum to DHFR. Additional studies revealed only a liver sample to contain significant amounts of an inhibitor of DHFR activity. It is postulated either that low levels of DHFR in fresh human tissue reflect low cell turnover or conversely that high levels in vitro and in animal tissues reflect high levels of enzyme due to selection because of high levels of folic acid in culture medium and prepared feeds.

Anticonvulsant action of amino acid antagonists against kindled hippocampal seizures

Electrical stimulation of the ventral hippocampus 5 times daily produced significant seizure activity (stage 4), but further stimulations seldom produced full motor seizures (stage 5). Blockade of these seizures with amino acid antagonists, phosphonocarboxylic acids, was achieved but with a reverse order of potency to that seen with the kindled amygdala. Thus APB was the most potent and APH the least potent analog tested. These results indicate that the kindling of different limbic brain areas may involve different neuronal substrates even if the development of the seizure activities are similar.

The kindled amygdala model of epilepsy: anticonvulsant action of amino acid antagonists

The amygdalas of rats were stimulated daily to produce kindled epilepsy. Superfusion of the ipsilateral ventricle allowed collection of amino acids before, during and after stimulation. At the stage where stimulation evoked full seizures there was a correlated increase in the extent of glutamate release. Other amino acids, including aspartate, showed no significant changes at this time. Aspartate, threonine and serine showed smaller responses not significantly different from those seen at the pre-kindled stage. Antagonists of excitatory amino acids (omega-phosphono-alpha-amino dicarboxylic acids) effectively antagonized both the behavioral and electrical components of the kindled seizures.

Actions of a tremorgenic mycotoxin on amino acid transmitter release in vivo

The tremorgenic mycotoxin verruculogen was administered directly into the brain of freely moving rats by the use of cannula systems that superfused either the cortical surface or the lateral ventricular space. The tremor produced by these CNS routes was compared with that produced by i.p. administration of the toxin or the dried mycelium of the fungus that synthesizes the verruculogen. The nature and degree of tremor produced by the central vs peripheral routes suggest that the site of action of verruculogen is not immediately adjacent to the cannula sites in the brain. Measures of the amino acids in the superfusates collected during the verruculogen-induced tremor showed an increase in the excitatory neurotransmitters, glutamate and aspartate in superfusates from the lateral ventricle but not in superfusates from the cortical surface. The differential effect on transmitter release suggests that a subcortical action of verruculogen is responsible for its tremorgenic activity.

A comparative study of sheep and pigs given the tremorgenic mycotoxins verruculogen and penitrem A

The moulds Penicillium simplicissimum and P crustosum and the tremorgenic mycotoxins, verruculogen and penitrem A, isolated from them, were given to sheep and pigs to compare their potencies. Pigs were generally less susceptible and in both species penitrem A was less potent than verruculogen. Five-month-old lambs seemed more susceptible to mycelium containing verruculogen than were 15-month-old sheep given a similar oral dose relative to bodyweight. Repeated daily dosing of lambs and sheep for five days with P simplicissimum failed to enhance the effect, indicating that verruculogen toxicity was not cumulative. Long and short acting barbiturate anaesthesia blocked the effects of lethal doses of tremorgens. Sedation with diazepam diminished, but did not block, mycotoxin-induced tremors suggesting that there was no specific action of this anticonvulsant sedative on tremorgens.

Total body water measurement in humans with 18O and 2H labeled water

Deuterium or tritium labeled water traditionally has been used for the measurement of total body water by application of the dilution principle. However, these methods have not enjoyed wide clinical use. The use of deuterium is hampered by the tedious and time consuming nature of the analysis while the use of tritium involves a radiation hazard. In addition, exchange of the label with nonaqueous hydrogen in the body raises questions about the accuracy of total body water values. To determine if water labeled with the stable isotope 18O can yield faster and more accurate results, total body water was measured simultaneously using water labeled with both 18O and 2H. The 18O and 3H dilutions were measured by mass spectrometry. The relative precision of the body water value using the 18O method was 2% for both serum and breath analysis. The 18O was fully equilibrated within 2 to 3 hr after administration, and results from the analysis of breath CO2 could be readily obtained within 1 hr after sampling. The H2(18)O dilution space averaged 3.0% (SE = 0.4) less than the 2HHO dilution space, because the latter exchanges with nonaqueous hydrogen. For this reason, the H2(18)O dilution should be a more accurate measure of total body water than the 3HHO dilution.

Spontaneous mechanical alternans in papillary muscles from atherosclerotic rabbits

Mechanical alternans developed spontaneously in 5 of 17 right ventricular papillary muscles from atherosclerotic rabbits. The rabbits had eaten an atherogenic diet of 5% lard, 5% peanut oil, 0.5% cholesterol, and 89.5% rabbit pellets for 116-184 days. In one muscle mechanical alternans developed slowly and persisted. When the condition had developed fully, in the weaker contraction the muscle shortened only 20% as far when contracting isotonically and developed only 38% as much tension when contracting isometrically. Added to the superfusate, calcium (5.0 mM) or norepinephrine (1.5 X 10(-5) M) abolished the alternans. In four muscles mechanical alternans was only temporary. Compared with the 12 muscles that did not develop alternans, these 4, when contracting isometrically 12 times/min but not in alternans, had longer latency and required more time to develop tension at the maximum rate and to develop peak tension. Contracting isotonically, they required more time to accelerate to maximum velocity of shortening and to shorten maximally. Raising the contraction frequency to 24/min decreased the differences in performance between the two groups. Norepinephrine (1.5 X 10(-5) M) made the differences smaller still. We think that both the mechanical alternans and the differences in performance between the muscles that developed alteranans and those that did not resulted from a defect in the cardiac cell's handling of calcium. Diet-induced changes in the lipid composition of the sarcoplasmic reticulum or sarcolemma or both seem probable causes.

Decreased myocardial contractility in papillary muscles from atherosclerotic rabbits

To determine the effect atherosclerosis has on myocardial contractility, we studied the contractile properties of right ventricular papillary muscles from 34 atherosclerotic and 17 control rabbits. We produced atherosclerosis by feeding for 2 to 8 months a diet of 5% lard, 5% peanut oil, 0.5% cholesterol, and 89.5% rabbit pellets. The controls received only rabbit pellets during the same time interval. Contracting isometrically 12 times per minute at 25 degrees C, muscles from the atherosclerotic rabbits developed tension at a lower maximum rate (max dT/dt), had a longer latency, and required longer to develop tension at the maximum rate and to develop peak tension. In isotonic contractions, they shortened with lower maximum velocities and required longer to accelerate to maximum velocity and to shorten maximally. We found no evidence that developed tension or distance shortened differed between the two groups of muscles. Raising the contraction frequency to 24 contractions per minute between the two groups of muscles. Raising the contraction frequency to 24 contractions per minute brought performance of the two groups of muscles closer in both types of contraction. Norepinephrine (1.5 x 10-5 M) nearly abolished differences between performance of the two groups. The loss of contractility correlates poorly with coronary and aortic atherosclerosis. It occurred early in the feeding of the atherogenic diet. We think it was due to a lipid-induced defect in the cardiac cell's handling of calcium.

Noninvasively and invasively measured pulsatile haemodynamics with graded arterial stenosis

Pulsatile haemodynamics associated with graded degrees of experimentally produced stenosis were studied in the canine femoral artery. Invasively determined pulsatile blood flow and noninvasively determined blood velocity with Doppler ultrasound were measured an average of 1.3 and 2.3 cm proximal to the stenosis, respectively. Pulsatile blood pressure was measured 0.6 cm proximal and 3.7 cm distal to the stenosis. With increasing severity of stenosis there were progressive increases in the femoral artery hydraulic input impedance moduli and in the ratio of the impedance moduli to the zero harmonic impedance (or total resistance). This resulted in: a) a progressive reduction in the Fourier harmonic moduli and pulsewave amplitudes of flow, velocity, and distal pressure; b) a progressive increase in the fifth-seventh proximal pressure harmonic moduli; but c) little change in mean proximal pressure or its first 4 harmonic moduli. The data confirm the well known phenomena of a 'critical stenosis' in that there is little decrease in resting mean blood flow until there is a 70 to 80 stenosis (area reduction). Also the oscillatory portions of the femoral artery data were more sensitive to the changes in stenosis than were the nonoscillatory parameters, which confirms previously reported findings from the thoracic aorta. However, the femoral artery haemodynamics exhibited a greater amount of frequency dependent behaviour than the thoracic aorta which is probably the result of a more complex interaction of reflections from the stenosis and from the periphery in the femoral artery than in the thoracic aorta. The sensitive changes in oscillatory haemodynamics may provide a useful basis for noninvasive and invasive physiological assessment of human peripheral atherosclerotic stenosis and of experimental stenosis in animals.

Brief communication. Inability of hexamethonium to block the discriminative stimulus (SD) property of nicotine

Rats were trained to discriminate between levers on a white or black wall to obtain food reinforcement, using nicotine or saline administration as the discriminative stimulus (SD). When hexamethonium was administered, either peripherally or intraventricularly, before the nicotine injection these rats responded as though they had received nicotine alone. This indicates that nicotine receptors responsible for its SD property are not blocked by hexamethonium, or alternatively that it is necessary to block the peripheral and central actions simultaneously to completely eliminate the cueing effect of the nicotine injection.

Lymphoepithelioma of the vocal cord

Lymphoepithelioma is a predominantly nasopharyngeal tumor with some incidence elsewhere in the pharynx. Occurrence in other sites is unusual. This report presents an example of a lymphoepithelioma arising in the vocal cord. The basal cells of the squamous epithelium lining the tonsillar crypts bear a close resemblance to the cells of this tumor, and they are intimately related to lymphoid tissue. It is our belief that lymphoepitheliomas arise from the basal zone and that the basal layer of epithelium even further afield might on occasion produce the lesion.

Composition of and cholesterol in Araucana and commercial eggs

Araucana eggs from six sources and commercial-type white eggs of two major supermarket brands and from the University of California flock were collected and analyzed for cholesterol content of the yolk. The yolks of Araucana eggs were significantly higher in cholesterol than those of commercial white eggs.

Operant behavioural and neurochemical effects after neonatal 6-hydroxydopamine treatment

Newborn rats were treated at 1 and 2 days after birth with 100 mg/kg 6-hydroxydopamine (60HDA), s.c. Testing on several operant behavioural tasks was begun at 6 months of age. On a fixed ratio 30 (FR 30) schedule of food reinforcement, the neonatal 60HDA treated rats responded at a significantly higher rate. Further analysis of the FR 30 response pattern indicated that the higher rate was due to a decrease in the amount of time spent pausing after the receipt of each reinforcer. The 60HDA treatment failed to alter the rat's behaviour during the extinction of the FR 30 response and on the progressive ratio or variable interval schedules of food reinforcement. Biochemical analysis of several brain areas at 9 months of age showed a decrease in noradrenaline (NA) levels in the cerebral cortex and hippocampus, while in the pons-medulla NA content was doubled. The tyrosine hydroxylase activity in these same brain areas was not significantly altered, but there appeared to be some decrease in the activity of this enzyme in the hippocampus. Comparison of the operant behavioural effects seen after various lesioning procedures in this and other studies, suggest the effects on FR performance are a result of destruction of NA neurons in the hippocampus and/or the apparent regeneration of neurons in the pons-medulla.

Differential actions of d- and 1-amphetamine on the metabolism of 3H-norepinephrine in rat brain

Approximately equieffective doses of d- and l-amphetamine, using suppression of operant fixed-ratio responding for food reinforcement as the determinant of potency, were compared for their ability to alter the disposition of the major and minor metabolites of NE in push-pull perfusates from rat brain lateral ventricle. While 3 mg d-amphetamine/kg and 6 mg l-amphetamine/kg both increased total 3H and the relative amounts of the minor metabolites 3H-normetanephrine and 3H-dihydroxymandelic acid, only 1-amphetamine caused a significant increase in the major 3H-NE metabolite, methoxyhydroxyphenylethylene-glycol. The data is discussed in relation to the abilities of the isomers of amphetamine to stereoselectively interact with noradrenergic neurons at doses that produce similar effects upon operant behavior.

Lipid composition and synthesis in the muscles of normal and dystrophic chickens

The lipids of the superficial pectoral muscle of 5-week-old normal and dystrophic New Hampshire chickens were fractionated by thin-layer chromatography procedures. Total lipid in the dystrophic muscle was fivefold greater than in normal muscle with the triglycerides 15-fold greater and the phospholipids 1.5-fold greater (wet weight basis). The relative proportions of phospholipids were quite similar except for significantly less phosphatidylcholine and phosphatidic acid in the dystrophic muscle. In another study acetate-2-14C was injected intraperitoneally into normal and dystrophic chickens which were killed at various times up to 7 days after the administration. The dystrophic birds incorporated acetate-2-14C to a greater extent into total lipids, triglycerides, and phospholipids of the muscle than normal chickens. The turnover times for both triglycerides and phospholipids were much greater in dystrophic than in normal chickens with the triglycerides showing a longer time than the phospholipids. In vitro incubation of acetate-2-14C with muscle slices showed a greater rate of incorporation into lipid by dystrophic than by normal muscle. These results indicate that the difference in acetate incorporation between normal and dystrophic muscle was due to metabolism in the muscle itself and not entirely a result of mobilization of lipid from other tissues.