A randomized comparison of three post-tonsillectomy diets*

Traditionally, soft cold foods have been recommended after tonsillectomy to aid comfort and haemostasis but, more recently, rougher foods have been advocated to promote physiologically normal deglutition. This trial was designed to discover whether post-tonsillectomy dietary advice has any influence on recovery. 150 patients due to undergo tonsillectomy were prospectively randomized to 1 of 3 diets: mainly rough food, mainly soft food, and no advice except to eat regularly. Food consumption, analgesia intake and pain levels were recorded daily by each patient. Tonsillar fossa slough and secondary haemorrhage were evaluated 1 and 2 weeks after surgery. Results of 137 patients were obtained. There were no significant differences between the diets regarding post-operative pain, analgesic required, healing rates or secondary haemorrhage. Specific post-tonsillectomy dietary advice need not be given, other than to encourage regular eating.     

Inappropriate ICD Discharges in Single-Chamber Versus Dual-Chamber Devices in the Pediatric and Young Adult Population

Background: Implantable cardioverter defibrillator (ICD) use is increasing in young patients and is frequently complicated by inappropriate device discharges (IDs), leading to discomfort, anxiety and, potentially, proarrhythmia. Dual-chamber (DC) ICDs may decrease IDs by improving rhythm discrimination, but are associated with increased size, expense, and implant complications. We examined whether the frequency of IDs was the same in dual- and single-chamber (SC) ICDs in young patients.
Methods: A multicenter review of patients ≤30 years of age with ICDs was performed. Demographic data and number of appropriate discharges (ADs) and IDs were collected. ADs and IDs were categorized after review of the episode by the primary electrophysiologist.
Results: Of 168 subjects (SC = 52; female = 76), 41 patients received 139 ADs, while 35 patients received 159 IDs. There were no differences related to gender or primary diagnosis, but patients with SC versus DC devices were younger (12.3 ± 5.0 years vs 14.9 ± 4.4 years, P < 0.0001) at implant. SC and DC devices were implanted with the same frequency for primary and secondary prevention. There were no significant differences in the incidence of IDs or ADs between the patients with SC or DC devices (AD: 12/52 SC vs 29/116 DC, P = 0.79; ID 7/52 SC vs 28/116 DC, P = 0.13).
Conclusion: In this cohort of young patients, DC ICDs did not provide added protection from IDs. Hence, the added complexity and cost of an atrial lead appear unwarranted if used solely for assistance with rhythm discrimination in young patients.     

Delusions of Pregnancy in the Elderly

We present five case reports of elderly ladies with delusions of pregnancy. This symptom is discussed with reference to the cases and a review of the literature. © 1997 by John Wiley & Sons, Ltd.     

AN EMPIRICAL COMPARISON OF STATISTICAL TESTS FOR ASSESSING THE PROPORTIONAL HAZARDS ASSUMPTION OF COX'S MODEL

In the analysis of survival data using the Cox proportional hazard (PH) model, it is important to verify that the explanatory variables analysed satisfy the proportional hazard assumption of the model. This paper presents results of a simulation study that compares five test statistics to check the proportional hazard assumption of Cox's model. The test statistics were evaluated under proportional hazards and the following types of departures from the proportional hazard assumption: increasing relative hazards; decreasing relative hazards; crossing hazards; diverging hazards, and non-monotonic hazards. The test statistics compared include those based on partitioning of failure time and those that do not require partitioning of failure time. The simulation results demonstrate that the time-dependent covariate test, the weighted residuals score test and the linear correlation test have equally good power for detection of non-proportionality in the varieties of non-proportional hazards studied. Using illustrative data from the literature, these test statistics performed similarly. © 1997 by John Wiley & Sons, Ltd.     

Random coil conformation for extended polyglutamine stretches in aqueous soluble monomeric peptides

Several neurodegenerative diseases have been found to be strongly associated with proteins containing a polyglutamine stretch which is greatly expanded from approximately 20 glutamines in normal individuals to more than 40 in affected individuals. A conformational change in the expanded polyglutamine stretch has been suggested to form the molecular basis for disease onset. Model peptides containing polyglutamine tend to aggregate and become insoluble. We have synthesized readily water-soluble monomeric peptides by flanking polyglutamine stretches with sequences rich in alanine and lysine. Circular dichroism measurements show that polyglutamine stretches of length 9 or 17 adopt a random coil configuration in aqueous solution. We think that in the disease-associated peptides for normal individuals the stretches of ～20 glutamines are in a random coil conformation, whereas in affected individuals the polyglutamine stretch may be in some other conformation. Our method to design soluble monomeric peptides containing extended polyglutamine stretches may be generally useful in studying other highly aggregating peptides.     

Correlation of Spontaneous and Induced Premature Atrial Complexes Initiating Atrial Fibrillation in Humans: Electrophysiologic Parameters for Guiding Therapy

INTRODUCTION: The low frequency of spontaneous premature atrial contractions (PACs) may be an impediment to mapping and ablation of atrial fibrillation (AF). It has been shown that PACs following external or internal cardioversion of AF can initiate AF. If this method could reproducibly induce PACs from the same location as spontaneous PACs, it would be clinically significant. High-resolution noncontact mapping can map a single beat, should help identify the sites of spontaneously occurring PACs and PACs induced following cardioversion of spontaneous or induced AF, and could help correlate the trigger sites for AF induction. METHODS AND RESULTS: Twelve patients (8 men and 4 women; mean age 49+/-10 years) with spontaneous PACs were included in the study. In all patients, AF was induced and subsequently cardioverted to assess and map isolated PACs or PACs that induced AF. Using the EnSite 3000 noncontact mapping system, mapping was performed of spontaneously occurring isolated PACs and PACs that induced AF and PACs (both with and without AF) that occurred on at least two different occasions following cardioversion. The locations of the spontaneous and the induced PACs were similar; 97% of induced PACs came from the same locations as those of spontaneous PACs (P = 0.5). Radiofrequency lesions guided by this mapping technique were delivered at 14 pulmonary vein sites. Following a single ablation attempt during a mean follow-up of 19+/-4 weeks, 42% of the patients were in sinus rhythm and drug-free, whereas an additional 24% of patients could be maintained in sinus rhythm on drugs that had failed before. CONCLUSION: There is a high degree of correlation between spontaneous and induced PACs as the trigger sites for AF initiation. Cardioversion of spontaneous or induced AF could be used as an electrophysiologic parameter for guiding therapy.     

Slope‐only glomerular filtration rate and single‐sample glomerular filtration rate as measurements of the ratio of glomerular filtration rate to extracellular fluid volume

Aims: The Jacobsson single‐sample equation for measuring glomerular filtration rate (GFR) after bolus injection is based on two factors of questionable theoretical validity for correcting the single‐compartment assumption. The aims were to redevelop a more transparent equation, show its fundamental similarity with ‘slope‐only’ GFR and compare it with the original equation and with slope‐only GFR. Methodology: The modified Jacobsson equation is k = (1/t).ln[V(t)/V(0)], where k is the rate constant of the terminal exponential and V(0) and V(t) are distribution volumes at times 0 and t. V(0) exceeds extracellular fluid volume (ECV): that is k′ = (1/t).ln[V(t)/ECV], where k′ > k. Moreover, [GFR/ECV] >k (= k + [15.4.k²]). The ratio k/k′ was determined in 476 patients to calculate single‐sample k (3 or 4 h post‐injection). Slope‐only and single‐sample GFR/ECV were measured using Cr‐51‐EDTA in 105 further studies, multiplied by ECV (estimated from weight), scaled to 1.73 m² and compared with GFR/1.73 m² from the original Jacobsson equation against reference multi‐sample GFR/1.73 m² simultaneously and independently measured with iohexol. Results: The relation between k and k′ was linear. k/k′ was 0.827 at 3 h and 0.864 at 4 h. There was no difference in bias or precision between the original Jacobsson and modified equations. In both, precision was better than slope‐only GFR/BSA. When GFR remained scaled to ECV, slope‐only GFR showed marginally better precision against reference GFR/ECV. Conclusions: Single‐sample and slope‐only techniques give GFR as k. Although the theory of the modified Jacobsson equation is more transparent than the original equation, it gives the same result. It is, however, easier to use.