High and Low Strength Nonsynchronized Shocks Given During Canine Ventricular Tachycardia

Cardioversion shocks given during ventricular tachycardia may cause ventricular fibrillation or acceleration of ventricular tachycardia, or arrest the tachycardia. A recently proposed theory may explain why the former two phenomena may occur. Briefly, this theory states that potential gradient shock fields of a critical strength delivered to tissue with a critical degree of refractoriness will cause circulating wave fronts of ventricular activation ("rotors") manifest as ventricular arrhythmia. We tested this theory by delivering nonsynchronized shocks 50% higher than defibrillation threshold or 50% lower than defibrillation threshold during 275 episodes of ventricular tachycardia in eight dogs with 5- to 7-day-old myocardial infarcts. Shocks stronger than the defibrillation threshold are likely to create shock fields in the ventricles everywhere stronger than this critical value, and therefore would not generate rotors. Shocks less strong than the defibrillation threshold may create shock fields within the ventricles that include the critical value, and therefore cause rotors if given when critically refractory tissue is present. Nonsynchronized shocks were used to increase the likelihood of encountering tissue with a critical degree of refractoriness. Ventricular fibrillation or acceleration of ventricular tachycardia occurred following 83 of 138 (60%) low strength shocks and following 20 of 137 (14.6%) high strength shocks. The pooled odds ratio for induction of ventricular fibrillation or accelerated ventricular tachycardia after low strength shocks as compared to high strength shocks was 8.9. Conclusion: when given during ventricular tachycardia, low strength shocks are much more likely to cause ventricular fibrillation or accelerated ventricular tachycardia than are high strength shocks (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Benzodiazepine use among heroin users: Baseline use,current use and clinical outcome

Introduction and Aims. Benzodiazepine use is associated with elevated levels of harm. The current study aimed to ascertain the long‐term nature of the relationship between benzodiazepine use and clinical profile among heroin users. Design and Methods. Longitudinal cohort, with follow‐up at 3, 12, 24 and 36 months. Participants were 615 heroin users recruited for the Australian Treatment Outcome Study. Results. At baseline, current benzodiazepine users were more likely to be committing crime, had poorer psychological health and poorer physical health. Baseline benzodiazepine use was not associated with the likelihood across follow‐up of heroin use (P = 0.44), committing crime (P = 0.17), poorer psychological health (P = 0.31) or poorer physical health (P = 0.48). Current benzodiazepine use was, however, associated with a greater likelihood of concurrent heroin use (OR 2.77), crime (OR 2.04), poorer psychological health (β = −4.47) and poorer physical health (β = −2.33). Discussion and Conclusions. Clinicians should be aware that reductions in benzodiazepine use are associated with reductions in harm, and that baseline benzodiazepine status does not equate to poor long‐term outcome. [Darke S, Ross J, Mills K, Teesson M, Williamson A, Havard A. Benzodiazepine use among heroin users: Baseline use, current use and clinical outcome. Drug Alcohol Rev 2009]     

Maternal Intake of Cruciferous Vegetables and Other Foods and Colic Symptoms in Exclusively Breast-Fed Infants

Objective We sought to assess relationships among components of maternal diet and the presence of colic symptoms among exclusively breast-fed infants aged ≤4 months.Design Data were collected by means of a mailed questionnaire that solicited information on the presence of symptoms of colic in infants and maternal intake of 15 foods (including four cruciferous vegetables) during the week before completion of the questionnaire.Subjects Exclusively breast-feeding women (n=272) and their 273 infants aged ≤4 months.Statistical analyses performed Dietary variables were analyzed categorically by logistic regression. Two-by-two tables were used to calculate relative risks.Results Relative risks (RRs) and 95% confidence intervals (CIs) for colic symptoms by food items the mothers consumed ranged from 0.7 (CI=0.3 to 1.5) for beef to 2.0 (01=1.1 to 3.5) for cow's milk. Maternal intake of cabbage (RR=1.3, CI=1.1 to 1.5), cauliflower (RR=1.2, CI=1.0 to 1.4), broccoli (RR=1.3, CI=1.0 to 2.2), cow's milk (RR=2.0, CI=1.1 to 3.5), onion (RR=1.7, CI=1.1 to 2.5), and chocolate (RR=1.5, CI=1.0 to 2.2) were significantly related to colic symptoms. Maternal intake of more than one cruciferous vegetable was associated with an RR of 1.6 (CI=1.1 to 2.4) for infants experiencing one or more colic symptoms.Conclusion Results of this study provide initial evidence that maternal intake of cruciferous vegetables, cow's milk, onion, or chocolate during exclusive breast-feeding is associated with colic symptoms in young infants. J Am Diet Assoc. 1996; 96:47-48.     

Cross-Validation of Prediction Equations for Resting Energy Expenditure in Young, Healthy Children

Objective To examine the accuracy of several prediction equations for resting energy expenditure (REE) in children.Design REE was measured in 113 prepubertal children (60 girls and 53 boys aged 3.9 to 7.8 years old, weighing 14.7 to 30.0 kg) using indirect calorimetry and compared with values estimated from the prediction equations of Altman and Dittmer, The Food and Agriculture Organization/World Health Organization/United Nations University (FAO/WHO/UNU), Maffeis et al, and Harris and Benedict.Statistical analysis Measured REE (MREE) was compared with predicted REE (FREE) by means of regression analysis. Prediction equations were considered accurate if the regression of MREE vs FREE was not significantly different from the line of identity (slope=l.0; INTERCEPT=0). Precision was assessed by the multiple correlation coefficient of the regression of MREE vs FREE.Results MREE was 938±119 kcal/day, and FREE was 1,057+224 kcal/day for the Altman and Dittmer equations, 956±84 kcal/day for the FAO/WHO/UNU equations, 948±64 kcal/day for the equations of Maffeis et al, and 954+102 kcal/day for the Harris-Benedict equations. The regression of MREE vs FREE was significantly different from the line of identity for all prediction equations except the FAO/WHO/UNU equations (slope=0.96, P=.735; INTERCEPT=–15 kcal/day, P=.885 for girls and SLOPE=1.08, P=.635; INTERCEPT=-62 kcal/day, P=.635 for boys). None of the equations was precise for MREE vs FREE (for all, R²<.6). For the FAO/WHO/UNU equations, less than half of the predictions were within ±50 kcal/day but 99% were within 200 kcal/day.Conclusion Most prediction equations for REE in children do not accurately or precisely estimate REEs. The exception is the FAO/WHO/UNU equations, which are reasonably accurate and precise for practical purposes. J Am Diet Assoc. 1997;97: 140–145.     

Synthesis of human β-endorphinyl-thiolglycine and its use for the preparation of affinity columns of β-endorphin

The peptide human β-endorphinyl-thiolglycine (I) has been synthesized by the solid-phase method. The citraconyl derivative of peptide I was coupled to aminohexyl-Sepharose by reaction with silver nitrate/N-hydroxysuccinimide in water. The citraconyl groups were removed in aqueous acetic acid and the resulting resin was used in affinity chromatography for the purification of antisera to β-lipotropin and β-endorphin.     

Unusual skin eruption with eosinophilia associated with hyperthyroidism

An unusual skin manifestation of Graves disease is described which varied from exfoliative dermatitis to toxic erythema and to more circumscribed ‘fixed urticaria’. There were also lichenoid lesions. Persistent pyrexia, eosinophilia and a raised ESR were also present. Other features of hyperthyroidism included myopathy and arthropathy. It is suggested that an immunological mechanism could account for the unusual manifestations in this patient.     

Semiquantitative analysis of collagen types in the hypertrophied left ventricle

Cardiac fibrosis is a characteristic feature of left ventricular hypertrophy. The aim of this study was to develop a simple and accurate method to analyse collagen accumulation, taking into account the variation in cardiac muscle fibre orientation and nonuniform collagen distribution. This technique was used to determine the amount and types of collagen that accumulate during pressure overload cardiac hypertrophy. These data were correlated with myocyte size, and with the diastolic stress–strain relationship of the intact myocardium. Myocyte size was significantly increased in the hypertrophied hearts, compared with age and sex matched controls (control 363±25 μm² vs experimental 244μm²; mean± S.E. , P < 0.05). No overall collagen accumulation was observed in the hypertrophied hearts, but a significant increase in collagen I was found with a reduction in the amount of collagen III in experimental animals. Since no increase in diastolic stiffness of the hearts was observed, these results indicate that an increase in the overall collagen content of the heart, rather than the upregulation of a specific type, may be necessary to cause diastolic dysfunction.     

Immunization with irradiated Plasmodium berghei sporozoites induces IL-2 and IFNγ but not IL-4

Protective immunity against Plasmodium induced by immunization with irradiated sporozoites (SPZ) depends on both humoral and cellular responses. Although circumsporozoite protein (CSP)-specific cytolytic T lymphocyte responses have been established as an effector system, other cell types are required for protection. We have previously demonstrated that although protective immunity and T cell proliferative reactivity to SPZ are mouse strain- and SPZ dose-dependent, no correlation between the two responses could be found. Since protective immunity involves functionally diverse T cell subsets, we asked whether the discordance between proliferative responses to SPZ and protective immunity might have resulted from selective activation of either the Th1 or Th2 cell subset. Protective immunity, in vitro proliferative responses, and lymphokine production were tested in BALB/c, C57Bl/6, and C3H/HeN mice immunized according to different SPZ regimens. The levels of IL-2 paralleled the proliferative reactivities in each mouse strain examined. Although IFNγ levels were present in the unprimed lymphocyte cultures, they increased following each SPZ immunization, in C57Bl/6, moderate in C3H/ HeN, and lowest in BALB/c splenic cultures. Surprisingly. no IL-4 was detected in splenic cultures from any mouse strain during proliferative activity or protective immunity. In contrast, elevated IL-6 production was noted after each immunization, regardless of the protective status and it correlated with anti-CSP IgG serum levels. These data establish that lymphokine profiles corresponding primarily to the Th1 cells were induced by immunization with P. berghei SPZ and that IL-4 secreting T cells were not induced by the SPZ-stage berghei antigens.